Appendix B (F-B) - Construction Stormwater Plan

ALBEMARLE" HL\TC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan—July 12, 2024
Albemarle Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan
KM 61-CI-RP-00101
Report Prepared for
Albemarle Corporation
4250 Congress St 1� Albemarle
Charlotte, NC 28209
AU gw,HI �,Sri.aUhcu-Wkerry, Ka�wqK KaZi e.r, Ti4�
2024-07-12 C Permitting S.Aluguvelli K.Wherry T. Kaiser
2024-04-04 B Review S.Aluguvelli K.Wherry T. Kaiser
2024-03-29 A Review S.Aluguvelli K. Wherry T. Kaiser
Date Rev. Status Prepared By I Checked By Approved By Approved B
HUTCH Client
H371132-4000-220-230-0001, Rev. C
Page
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.� L �� �: 1I.� �: LL HATCH
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan—July 12, 2024
Table of Contents
1. Introduction...........................................................................................................................................1
1.1 Purpose......................................................................................................................................... 1
1.2 Scope............................................................................................................................................ 1
2. Project Description...............................................................................................................................1
2.1 Project Facilities and Infrastructure .............................................................................................. 1
2.2 Existing Conditions .......................................................................................................................2
2.2.1 Climate............................................................................................................................2
2.2.2 Surface Water Conditions...............................................................................................3
2.3 Floodplain .....................................................................................................................................4
3. Applicable Legislation and Guidelines ..............................................................................................5
3.1 Regulatory Requirements and Guidelines....................................................................................5
3.1.1 Federal............................................................................................................................5
3.1.2 North Carolina.................................................................................................................5
4. Construction Schedule........................................................................................................................6
5. Stormwater Runoff Calculations for Erosion and Sediment Control (ESC) Best
Management Practices (BMPs)...........................................................................................................8
5.1 Design Objective...........................................................................................................................8
5.2 Design Criteria..............................................................................................................................8
5.2.1 Temporary Stormwater Controls.....................................................................................8
5.2.2 Permanent Stormwater Controls.....................................................................................8
5.3 Construction Phasing Stormwater Management Plans................................................................9
5.3.1 Stormwater Management BMPs................................................................................... 10
5.3.2 Culvert, Channel and Sewer Analysis........................................................................... 11
5.4 Design Basis and Assumptions.................................................................................................. 11
6. Construction Water Management Erosion and Sediment Control Best Management
Practices..............................................................................................................................................14
6.1 Rock Construction Entrance....................................................................................................... 14
6.1.1 Design Standards - Rock Construction Entrance ......................................................... 15
6.1.2 Maintenance - Rock Construction Entrance ................................................................. 15
6.2 Diversion Berms.......................................................................................................................... 16
6.2.1 Installation -Wedge Diversion Berms........................................................................... 16
6.2.2 Maintenance -Wedge Diversion Berms ....................................................................... 16
6.3 Compost Filter Socks and Sediment Fence ............................................................................... 16
6.3.1 Design Criteria —Compost Filter Socks........................................................................ 17
6.3.2 Installation —Compost Filter Socks............................................................................... 19
6.3.3 Maintenance—Compost Filter Socks ........................................................................... 19
6.4 Rolled Erosion Control Blankets.................................................................................................20
6.4.1 Installation - Erosion Control Blankets..........................................................................20
6.4.2 Maintenance— Erosion Control Blankets......................................................................21
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HATCH
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan -July 12, 2024
6.5 Pumps/ Pumped Water Filter Bags ............................................................................................21
6.5.1 Installation — Pumped Water Filter Bags.......................................................................22
6.5.2 Maintenance— Pumped Water Filter Bags ...................................................................22
6.6 Sediment Ponds..........................................................................................................................22
6.6.1 Maintenance—Sediment Ponds...................................................................................23
6.7 Rip-Rap Channels.......................................................................................................................23
6.8 Dust Control................................................................................................................................23
6.9 Temporary Seeding ....................................................................................................................23
6.9.1 Topsoil Application........................................................................................................24
6.9.2 Seed Mixtures ...............................................................................................................24
6.10 Inlet Protection............................................................................................................................27
6.10.1 Installation - Inlet Filter Bags.........................................................................................28
6.10.2 Maintenance— Inlet Filter Bags.....................................................................................28
6.10.3 Installation — Stone Inlet Protection ..............................................................................28
6.10.4 Maintenance—Stone Inlet Protection...........................................................................28
7. Construction Sequence for Erosion and Sediment Control Best Management Practices.........28
8. Sediment and Erosion Control Inspection and Maintenance Procedures, Operation and
MaintenancePlan ...............................................................................................................................29
8.1 Inspection Schedule ...................................................................................................................30
8.2 ESC BMP Maintenance Requirements.......................................................................................30
8.2.1 Maintenance— Inlet Filter Bags.....................................................................................30
8.2.2 Maintenance—Stone Inlet Protection...........................................................................30
8.2.3 Maintenance— Diversion Berms...................................................................................30
8.2.4 Maintenance— Rock Construction Entrance/Exit .........................................................31
8.2.5 Maintenance—Compost Filter Socks/Sediment Silt Fence..........................................31
8.2.6 Maintenance— Pumped Water Filter Bags ...................................................................32
8.2.7 Maintenance— Rolled Erosion Control Blankets...........................................................32
8.2.8 Maintenance— Rip-Rap Channels/ Rock Check Dams................................................32
8.2.9 Maintenance—Sediment Ponds...................................................................................33
8.2.10 Material Recycling and Disposal...................................................................................33
9. Water Quality Monitoring Program...................................................................................................34
10. Adaptive Management .......................................................................................................................35
11. References ..........................................................................................................................................35
List of Figures
Figure2-1 — Project Layout...........................................................................................................................2
Figure 2-2— Existing Streamflow Network....................................................................................................3
Figure 2-3— FEMA Floodplain Map..............................................................................................................5
Figure 4-1 — Construction Milestones ...........................................................................................................7
List of Tables
Table 5-1 —Onsite Drainage Basin Areas ..................................................................................................10
Table 5-2—Sediment Storage Volumes.....................................................................................................11
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HATCH
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan -July 12, 2024
List of Exhibits and Appendices
Exhibit A: Phase 1 - Construction Stormwater Management Plan
Exhibit B: Phase 2 - Construction Stormwater Management Plan
Exhibit C: Duke Substation Pad Construction Stormwater Management Plan
Exhibit D: Erosion and Sediment Control Details
Appendix A : Frequency Analysis Results from AWA& NOAA Atlas 14 Precipitation Map
Appendix B : Summary Peak Runoff Volume and Flowrate Calculations for Phase 1 BMPs
Appendix C : Proposed (Operational) Sediment Basins Sizing Calculations
Appendix D : Proposed Sewer Sizing Calculations
Appendix E : Channel and Culvert Capacity Analysis Results
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ALBEMARLE' HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan—July 12, 2024
List of Acronyms
AASHTO American Association of State Highway and Transportation Officials
BMP Best Management Practice
CSMP Construction Stormwater Management Plan
ESC Erosion and Sediment Control
of Degrees Fahrenheit
ft Feet
H Horizontal
1-85 Interstate Route 85
KMMP Kings Mountain Mine Project
Ktpa Kilo tonnes per annum
LHM Lithium Hydroxide Monohydrate
MDC Minimum Design Criteria
NC North Carolina
NCAC North Carlina Administrative Code
NCDEQ North Carolina Department of Environmental Quality
NPDES National Pollutant Discharge Elimination System
NPI Non-Process Infrastructure
O&M Operation and Maintenance
PPC Pollution Prevention Plan
Q1 First Quarter
ROM Run-Of-Mine
RSF Rock Storage Facility
SWMP Stormwater Management Plan
SWPPP Stormwater Pollution Prevention Plan
USEPA United States Environmental Protection Agency
NCDEQ North Carolina Department of Environmental Quality
PPC Pollution Prevention Contingency
V Vertical
WSB Water Storage Basin
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ALBEMARLE' HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
1. Introduction
The Kings Mountain Mine Project(KMMP) is located at a former mine site within the City of
Kings Mountain, North Carolina (NC). Mining and concentrating operations ceased at Kings
Mountain in the early 1990s, and the site infrastructure was decommissioned. The KMMP
aims to restart mining activities at the Kings Mountain Site and process ore to produce
sufficient spodumene concentrate to ship to offsite for further processing
The project facilities will be developed both north and south of the 1-85 and include an open
pit mine, rock storage facilities, run of mine (ROM) pad, crushing circuit, concentrator, north
and south non-process infrastructure (NPI) areas and associated infrastructure.
This document provides the construction sequencing and stormwater management controls
that will be implemented through the KMMP Construction Phase.
1.1 Purpose
The purpose of this document is to provide a phased approach for construction activities to
meet all applicable NC stormwater regulations as well as industry stormwater standards,
guidelines, and best management practices (BMPs). This plan is in alignment with the North
Carolina Erosion and Sediment Control Planning and Design Manual (North Carolina
Sedimentation Control Commission, May 2013).
Specific erosion control measures to be installed, prior to the commencement of construction
activities (clearing and grading) and following the completion of major earthwork activities,
have been identified to ensure erosion and sedimentation is controlled within the Project
area. It is anticipated that the erosion and sediment control (ESC)will be dynamic, changing
over time as conditions in the field change. Two specific plans or phases within the 2.5-year
construction phase were chosen for representation in this report. Specific plans for sediment
and erosion control are provided for the rock storage facilities, access/mine roads, and
process areas with a detailed sequence of installation and schedule for maintenance of the
measures. Engineering designs and calculations for these measures are also included.
1.2 Scope
This CSMP is applicable to the full Project site from commencement of construction through
to commissioning activities, approximately Year-2.5 to Year 0 with the completion of the
operational stormwater management infrastructure.
2. Project Description
2.1 Project Facilities and Infrastructure
This section describes the project facilities and associated infrastructure for KMMP that will
be developed during the Construction Phase. The main project facilities will include the Open
Pit, the Concentrator, ROM Pad/Crushing Circuit, South NPI, North NPI, 1-85 Bridge, Rock
Storage Facilities (RSF-X and RSF-A), Overburden/Stockpile Facilities (OSF), Concentrate
H371132-4000-220-230-0001, Rev. C
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Loadout, and Tailings Loadout. Additional infrastructure to support the facilities will consist of
haul roads, service roads, and site wide utilities. The project layout, including the mine and
processing areas is shown in Figure 2-1.
'... WPM—
"
OSf.) F
•r� r � vricme I r c
• L r
Figure 2-1 — Project Layout
2.2 Existing Conditions
2.2.1 Climate
The Project is located in southwestern North Carolina, where the climate is described as
continental without a dry season. Temperatures range from between 27 degrees Fahrenheit
(°F) and 65°F during the coldest months to above 720F during the warmest months. Average
annual precipitation is 42 inches, with an even distribution of rainfall throughout the year,
averaging between three and five inches per month. Average annual snowfall is four inches.
Southwestern North Carlina is prone to thunderstorms during the summer and ice storms
during the winter. The region is susceptible to extreme precipitation events, including tropical
storms and hurricanes, which can bring heavy rainfall and cause flooding
(SRK Consulting, 2023).
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
2.2.2 Surface Water Conditions
The site is in the Kings Creek watershed, part of the Broad River basin, which encompasses
1,513 square miles of western North Carolina and northwestern South Carolina. The
headwaters originate in the Blue Ridge Mountains and generally flow toward the southwest.
The Broad River basin has a varied landscape of forested land, pasture and row crop
agricultural land, and urban land, and is made up of 17 sub-watersheds, including Kings
Creek.
The existing drainage network is shown on Figure 2-2 and is summarized as follows. Kings
Creek enters the Project area from the northeast and is routed via a four-foot (ft) diameter
corrugated metal pipe culvert under the current Albemarle Research Building. Discharging
from the culvert, King Creek flows to the southwest and joins with the discharge from the
South Creek Reservoir before crossing under 1-85 in three, 7-ft wide by 10-ft high concrete
box culverts. Flowing south, Kings Creek joins with the discharge from Water Storage Basin-1
(WSB-1) before flowing off the Project area to the southwest.
-0
r
Y
t V7 T .►
Y: .1
i
Figure 2-2— Existing Streamflow Network
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ALBEMARLE' HATCH
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
South Creek Reservoir discharges to Kings Creek via a spillway consisting of two 32-inch
diameter culverts. Water Storage Basin 1 (WSB-1) is a shallow lake that collects runoff from
the watershed immediately upstream and discharges into a drainage that joins with Kings
Creek. The Kings Mountain Pit Lake does not discharge to the stream network, but
dewatering of the pit will discharge to Kings Creek when the Project is underway.
These drainage areas are currently a combination of partially cleared, grass covered and
wooded areas. The site can be described as undulating. Drainage patterns for the majority of
these drainage areas slope north to south and from east to west according to the contours of
the survey. Currently, there are sediment basins and roadside ditches along the northside of
1-85 that convey stormwater to Kings Creek.
Jurisdictional and non-jurisdictional wetlands are present at the site and are detailed in the
Wetland and Waterbody Delineation Report for the Albemarle Kings Mountain Lithium Mining
Project, Cleveland County, North Carolina (SWCA, 2022).
2.3 Floodplain
According to Federal Emergency Management Agency(FEMA)floodplain maps, a majority of
the project site is located in Zone"X" and lies outside of the 500-yr floodplain (i.e., outside of
1% and 0.2% annual probability floodplains). Flood Zone X is an area with low-to-moderate
flood risk as determined by FEMA. The FEMA FIRM Map Panel Number for the project site is
3710259400J. All project facilities are located outside of the FEMA 100-yr floodplain. The
FEMA floodplain's extents are shown in Figure 2-3. A copy of the FEMA National Flood
Hazard Layer FIRMette for the overall site is included in Appendix I. Stormwater conveyance
system management, collection, and detention facilities will be constructed to control the
increase in site runoff from the proposed development. The project construction activities will
disturb approximately 220 acres.
The location of the site area relative to the overall catchment area is shown in Figure 2-3.
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AALBEMARLE.' H LET C H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
r `;y- Legend
FIRM Pafiel
- ��r`.� 51re8rrl
- Zone AE-
1%Annual Chant
Flood Hazard
2aneX unshaded-
0.2%Annual Chance
Flood Hazard
.y
Map Source;FEMA National Flood Hazard Map,Panel P 37142594 Oj1
Map stale:NTS
Figure 2-3—FEMA Floodplain Map
3. Applicable Legislation and Guidelines
3.1 Regulatory Requirements and Guidelines
3.1.1 Federal
The Clean Water Act(40 CFR 122.44(d)(1)(vi)(B)), administered by the United States
Environmental Protection Agency (EPA), is the primary federal law governing water pollution,
requires the development of a Stormwater Management Plan (SWMP), and requires that
measures be put in place to prevent discharges of pollutants in stormwater runoff.
3.1.2 North Carolina
Applicable North Carolina regulations include:
• North Carolina Department of Environmental Quality (NCDEQ) Stormwater Rules North
Carolina Administrative Code Title 15A Subchapter 02H (15A NCAC 02H Stormwater
Rules).
• 15A NCAC Subchapter 02B - Surface Water and Wetland Standards, Section .0200
Classifications and Water Quality Standards Applicable to the Surface Waters and
Wetlands of North Carolina
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.�� ALBEMARLE"' HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
• 15A NCAC 02B.020815A NCAC 02B.0208 Standards for Toxic Substances and
Temperature - Specific and narrative standards for toxic substances in all North Carolina
waters
Applicable North Carolina guidance documents include:
• North Carolina Surface Mining Manual. A Guide for Permitting, Operation, and
Reclamation. State of North Carolina Department of Environmental, Health, and Natural
Resources. Division of Land Resources. Land Quality Section. February 1996
• Erosion and Sediment Control Planning and Design Manual. North Carolina. May 2013.
North Carolina Sedimentation Control Commission, North Carolina Department of
Environmental and Natural Resources, and the North Carolina Agricultural Extension
Services.
• The North Carolina Stormwater Design Manual is compatible with the minimum design
criteria (MDC)which are codified in the NCDEQ stormwater rules (15A NCAC 02H
Stormwater Rules).
4. Construction Schedule
The construction execution phase for the Project is anticipated to commence in August 2025
with an expected completion in the first quarter(Q1)of 2028, a time frame of approximately
2.5 years. Phase 1 construction commences at-2.5 years and continues to the completion of
earthworks, approximately 9 months. Phase 2 will commence with the remainder of the civil
works directly following completion of Phase 1.
The initial construction schedule has been developed based on the main facility areas to be
developed, activities within each area, and multiple work faces. The multiple work faces are
assumed to include the Open Pit, Concentrator, ROM Pad/Crushing Circuit, South NPI, North
NPI, 1-85 Concentrator Bridge, Kings Creek Haul Road crossing Rock Storage Facilities
(RSF-X and RSF-A), OSF 1 through 3, Concentrate Loadout, and Tailings Loadout. The
focus of the major construction activities will be the ROM Pad & Crushing Circuit as well as
the North NPI, South NPI and Concentrator areas.
A detailed construction schedule will be developed through subsequent project phases as
additional information related to engineering, and contracting and procurement schedules are
identified. The major construction milestones are provided in Figure 4-1 and are based on the
following assumptions:
• Permits required to allow work to commence in accordance with the schedule have been
obtained.
• Hours of Operation: 1 shift x 10 hours x 6-day work week.
Additional detail related to site-wide earthwork activities (black line) is provided for specific
project areas including the relevant sequencing and time frames for completion (brown lines).
H371132-4000-220-230-0001, Rev. C
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AALBEMARLE@ H AT C H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
NPI North lolil-651
Cnigslhmg Ci6to4 and ROM Pod[North of 1,95)
Cancentrarar[South of 1-851nciuchngw715and NPI South)
MrM1f Dey*komtrnk
Sde Wide Earthhvorks
Earthworks W5&1
Earthworks.North NPI
Earthworks erushff1Fmrn Rad
OorgyrQkn 5COSkpilf Facility$
dverlbwdleo%Kil lle Facility 2 1
dveribudlm Stockpile Facility 2
li FeSF-%
Earthworks Canrerhtratur
Earthworks RSF-A I
Earthwmrks Mire Reads
Atchdalf TSF-III
Site Development
"S Concentrator Bridge
Duke Easements
Duke Substation
Start rnanth
0 5 to i5 20 25 90 35 do =5 so
■End month
Mon"frgm$Kirk
Figure 4-1 —Construction Milestones
The sequence of activities in each of the area-specific work faces is as follows:
• Implement sediment and erosion control measures.
• Execute clearing and grubbing activities. Stockpile vegetation and woody debris
separately in designated areas, as per Environmental Management Plan.
• Develop access roads, temporary site service roads, and laydown areas.
• The mining fleet will begin moving bulk waste rock filling areas on the north side of the
interstate between Kings Creek and the interstate for facility locations.
• Commence grading to bulk cut-and-fill requirements.
• Place fill and install permanent drainage systems and erosion control structures [ROM
Pad wall].
• Develop utilities infrastructure.
• Develop permanent haul site service roads.
• Excavate for foundations and conduct piling as required.
• Construct permanent infrastructure.
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ALBEMARLE' HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Construction completion is the point where the permanent infrastructure has been
constructed in accordance with the job specifications and drawings to the extent that the
commissioning activities can commence.
5. Stormwater Runoff Calculations for Erosion & Sediment
Control (ESC) Best Management Practices (BMPs)
5.1 Design Objective
To collect, convey, and discharge clean stormwater safely into Kings Creek and South Creek
during various project construction activities utilizing a number of efficient stormwater ESC
BMPs such as diversion channels, riprap channels, sediment basins, culverts, outlet
structures, diversion berms, etc.
5.2 Design Criteria
The following standards and guidelines were utilized with respect to designing stormwater
runoff controls:
1. Erosion and Sediment Control Planning and Design Manual. North Carolina. May 2013.
North Carolina Sedimentation Control Commission, North Carolina Department of
Environment and Natural Reserves, and the North Carolina Agricultural Extension
Services
2. Surface Mining Manual. A Guide for Permitting, Operation, and Reclamation. State of
North Carolina Department of Environment, Health, and Natural Resources. Division of
Land Resources. Land Quality Section. February 1996
5.2.1 Temporary Stormwater Controls
For the design of temporary stormwater controls, the NC Surface Mining Manual (1996)
stipulates that:
1. Temporary diversions, those that function for less than a year, should be designed to
carry at least the 10-year design storm for the total drainage area.
2. Temporary diversions require erosion protection. Velocities over 2.5 ft per second may
require a temporary liner with supporting design calculations unless the soil is especially
erosion resistant.
3. Side slopes of the diversion berm should be constructed to 2 horizontal to 1 vertical
(2H:1V), or flatter. The slopes then should be immediately seeded.
5.2.2 Permanent Stormwater Controls
For the design of permanent stormwater controls, the NC Surface Mining Manual (1996)
stipulates that permanent stormwater controls such as ditches and channels, those
constructed to function for more than a year and to carry concentrated runoff non-erosively to
a predetermined destination, must be designed for the 25-year storm event for the total
drainage area, furthermore:
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ALBEMARLE' HATCH
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
1. Side slopes must be 2 horizontal (H)to 1 vertical (V), or flatter.
2. Grass-lined channels are generally used for slopes less than 5%.
3. Velocities should not exceed 5 ft per second for established grass lined channels.
4. Sharp bends and turns should be avoided.
5. Velocities over the maximum allowable design velocity for grass-lined channels require a
permanent structural lining such as riprap.
6. In cases where velocity allows, riprap may be installed in the bottom of the channel with
grass-lined side slopes to decrease the quantity of riprap needed. Filter fabric or a 6-inch-
deep sand gravel crushed stone filter must be installed under the riprap to prevent
undermining. The filter should extend under the entire area of the riprap lining.
7. The receiving channel or outlet must be protected from erosion by ensuring that the outlet
velocity is minimized.
8. Outlet protection should be included if necessary.
5.3 Construction Phasing Stormwater Management Plans
The proposed construction activities will occur in multiple phases as discussed in Section 4 -
Construction Schedule. The stormwater management controls shown in Phase-1 construction
SWMP supports earth disturbance/moving activities. The Phase 1 SWMP is included as
Exhibit-A in this report. The drainage area delineations and stormwater management controls
are shown in Phase 1 and Phase 2 Development Plans. The Phase 2 construction
stormwater management plan supports both temporary and operational stormwater
management facilities. The Phase 2 SWMP is included as Exhibit-B in this report.
The drainage areas labeled as Phase 1 A, Phase 1 B and Phase-1 C shown in the Phase 1
and 2 SWM plans are located on the north side of Interstate 1-85 in the ROM Pad and
Crusher areas. The drainage areas labeled as Phase 2A and Phase-213 are located on the
south side of Interstate 1-85 in the concentrator areas. The two (2)drainage areas depicted
Phase 3A and Phase-313 are located in the north NPI area. RSF-A and RSF-X are located on
the west side of crusher area. South creek bisects these RSF areas. There are three (3) Ore
Storage Facilities (OSF-1 through OSF-3) located on the north side of 1-85 as shown in the
construction SWM plans. OSF-1 is located to the west of the NPI area and north of RSF-A
area. OSF-2 is located to the south of the NPI area. OSF-3 is located south of RSF-A area.
Duke substation pad is located west of Water Storage Basin 1 (WSB-1)which abuts Galilee
Church Road on the north side The approximate areas of the onsite drainage catchment
areas as shown in the following Table 5-1.
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Table 5-1 —Onsite Drainage Basin Areas
Basin- ID Area (sq.ft.) Area (ac.$)
Phase-1A 191,664 4.4
Phase-1 B 1,197,900 27.5
Phase-1 C 914,760 21.0
Phase-2A 1,677,060 38.5
Phase-213 583,704 13.4
Phase-3A 2,744,280 63.0
Phase-313 962,676 22.1
OSF-2 1,519,746 34.9
OSF-1 1,067,753 24.5
OSF-3 373,247 8.6
Duke's Pad 461,562 10.6
5.3.1 Stormwater Management BMPs
In accordance with the requirements of the NCDEQ Stormwater Design manual, this project
proposes several construction stormwater management best management practices (BMPs).
Structural BMPs include retention basins, storm sewers, culverts, and riprap channels. The
primary surface runoff conveyance features during land disturbance activities are Riprap
Channels and Sediment ponds. The sediment ponds will discharge directly to Kings Creek.
Temporary sediment traps will be installed, to service areas less than 5 acres, for up to one
year. The storage capacity of the traps will be at least 1,800 cubic feet of storage per
disturbed acre of drainage area and will safely pass the 10-year, 24-hour design storm for the
total drainage area. Temporary channels will be designed to contain a minimum 10-yr storm.
Additional channels may be required to convey water from closed surfaces, which will be
developed during future phases of construction. Collection ponds adjacent to the two waste
rock dumps will receive surface runoff from the collection channels and may act to remove
sediments. Note that these collection ponds will transfer the water to the WSB-1 either
directly or through a water treatment plant (WTP)which will provide the final sediment control
capacity on contact water flow.
The sediment storage volumes required for proposed sediment basins in construction
SWMPs are shown in the following table:
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan -July 12, 2024
Table 5-2-Sediment Storage Volumes
Required Sediment Storage volume for Sediment Basins
Basin- 1D Area(sq_ft_) Area(ac_s) Req.Sed. Req. 10-fir Runoff Prodded Storage
Volume(cu.$) Volume(cu.ft) Volume(cu.ft)
Phase-1A 191.664 4.4 7.920 17.236 31.703
Phase-1B 1.197.900 27.5 49.500 121.911 13 8.57 8
Phase-1C 914.760 21.0 37.800 90.324 138.578
Phase-2A 1.677.060 38.5 69.300 200.849 219.780
Phase-2B 583.704 13.4 24.120 40.274 87.030
Phase-3A 2.744.280 63.0 113.400 250.773 301.530
Phase-3B 962.676 22.1 39.780 87.969 90.000
OSF-2 1.529.746 34.9 62.799 75.747 90.655
0SF-1 1.067.753 24.5 44.122 106.581 119:655
OSF-3 373.247 8.6 15.423 26.636 91.780
Duke's Pad 461.562 10.6 19.073 32.831 63.405
It should be noted that some of the BMPs (i.e. drainage channels, Sediment/detention
basins, outfall structures etc.) constructed during Phase 2 Construction as shown in Exhibit B
will serve as permanent or operational features. Specifically, ponds labeled as Sediment
Pond 1Awill serve as future Operational Pond M11, Sediment Pond 2A will serve as future
Operational Pond M12, Sediment Pond-213 will serve as future Operational Pond C01,
Sediment Pond 313 will serve as future Operational Pond M81 as shown in Appendix C.
Additionally, Duke sediment pond 1 with skimmer as shown in the construction SWM plan will
serve as future operational/permanent detention pond. Note that additional BMPs may be
require depending upon changes to construction staging and sequencing activities.
5.3.2 Culvert, Channel and Sewer Analysis
The Stormwater Calculations, Hydraulic and Hydrologic (H&H)Analysis Results for sizing
various BMPS that are shown in Phase 1 and Phase 2 construction SWM plans are included
in various Appendices of this report. The storm sewer analysis/culvert sizing was performed
by using Manning's Equation for analyzing sewer capacities, velocities, and hydraulic
gradient lines (HGL). The pipe material utilized in the hydraulic modeling is reinforced
concrete pipe. The Manning's roughness coefficient assumed is (n=0.013). The sewer
capacity analysis results are included in Appendix D. The pipe sizes, including sewer
alignment and design parameters will be finalized during final design and are contingent upon
the location of existing utilities, conflicts, and topographic field survey data. The channel and
culvert capacity analysis results are included in Appendix E.
5.4 Design Basis and Assumptions
In order to model both the existing and proposed site conditions, as well as to estimate the
approximate amount of storage/infiltration that will be required during construction and post
construction, several design methods were used:
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Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
1. Soil Conservation Service (SCS)TR-55 computer program, as implemented by
Hydraflow Hydrographs Extension from AutoCAD Civil 3D computer program (TR-55
Method), is used for determining the peak rates of runoff and their respective
hydrographs; storage estimation; and storm routing. Hydraflow Hydrographs Extension is
an application for urban hydro-systems engineering. It is designed primarily for hydrologic
analysis of both simple and complex drainage basins for determining runoff from various
historical and synthetic storms, and in planning or modeling flood control measures, such
as detention ponds, inlet, and outlet structures.
2. For pipe size estimating purposes, Rational Formula method is used for the design of the
storm sewer systems.
3. Hydraflow Express Extension tools from the Autodesk Civil 3D computer program is used
for determining single pipe culvert and drainage channel (i.e., grass, riprap etc.)
capacities. Hydraflow Express Extension is a computer program for performing hydraulics
and hydrology tasks, such as designing culverts, open channels, inlets, and weirs.
Hydraflow Express Extension enables you to quickly generate informative graphs, rating
curves, and on-screen reports as well as formal printed reports.
The computer programs listed above require input data consisting of several different
constants and variables. In order to obtain all of the information required by the programs,
certain assumptions were made concerning both existing and proposed site conditions. This
section discusses the input data and the assumptions used.
Because the rain events occurring at the project site vary significantly in both frequency and
intensity during any particular year, a site-specific storm depth duration frequency analysis
was developed for the Kings Mountain project site by Applied Weather Associates (AWA,
2022) and is utilized in hydrologic and hydraulic (H&H) models. It should be noted that this
precipitation data used in the computer models is more conservative than the storm data
obtained from Gastonia Station (31-3356) Kings Mountain NOAA Atlas 14 Point Frequency
Estimates. The Frequency Analysis Results table from AWA(2022), including precipitation
depths and rainfall intensities from NOAA are included in Appendix C for comparison
purposes.
Pre-Developed Runoff
The following information was utilized to determine the pre-developed runoff for the
watershed area:
Topography and site grading information has been taken from online mapping sources, such
as Google Earth Imagery, United States Geological Survey(USGS)topographic quadrangle
maps, three-dimensional (3D) contour data for Cleveland County received from Albemarle
and from specific verification surveys.
The land cover for the site is modeled as if the pre-developed conditions are wooded and
brush in good condition. This is a conservative approach versus what the existing or current
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ALBEMARLE' HATCH
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
conditions actually portray in order to determine the true runoff rates and volumes for the
proposed stormwater conveyance systems such as detention/retention systems and storm
sewer systems.
Based on soils data obtained from USDA Natural Resources Conservation Service (NRCS)
Web Soil Survey(WSS), the hydrologic soil classification for the vast majority of the site (up
to 70% of the site) in its existing condition is Udorthents, loamy, 0 to 15 percent slopes (UdC),
Uwharrie silty clay loam, 2 to 8 percent slopes, moderately eroded (UuB2). The soil type UdC
has been assumed to be Hydrologic Soil Group "B" and UuB2 as Hydrologic Soil Group "B"
based on the information furnished in the soil survey report. Therefore, an average for the
curve number is used between the two classes (both for pre- and post-developed conditions).
The Manning's Kinematic Equation as specified in TR-55 was used for estimating the
overland (sheet)flow travel time. Time of Concentration (Tc): Tc's for the drainage areas
were calculated based on sheet flow, shallow concentrated flow and open channel flow
regimes using TR-55 guidelines. An average precipitation of 3.41 inches (2-yr storm depth)
as required by TR-55 methodology is used for time of concentration computations. The
average velocities for estimating the travel time for shallow concentrated flow were from the
Average Velocity Chart adapted from National Engineering Handbook, Volume 4.
Post-Developed Runoff During Operations
The following information was utilized to determine the post-developed runoff for some of the
Phase 2 operational BMPs:
1. The primary collection systems for stormwater conveyance for the site drainage areas
are ditches, sewers, culverts, and sediment basins. Onsite stormwater runoff is primarily
captured and routed to sediment basins using these conveyance systems. The overflow
from sediment basins discharge by gravity to Kings Creek.
2. Ditches along the haul roads will collect storm runoff in small local sumps and will be
pumped to WSB-1.
3. The haul road channels, emergency spillways for sediment basins will be designed for
the 100-yr storm event for post construction.
4. Stormwater sediment/detention ponds are designed to accommodate 25-yr 24-hr storm
event storage volumes. The sediment basins are equipped with skimmers as well as
emergency spillways that are designed for a 100-yr rain event to discharge clean water
into Kings Creek. Skimmer surface drain floats on the surface of the sediment basin as it
fills and drains, releasing the clean water in the basin instead of draining from the bottom
as conventional outlets do. The skimmer drains the basin slowly over several days and at
a constant rate to maximize settling. The skimmer details are included in Exhibit-D,
Erosion and Sediment Control Detail Sheet, KM61-CI-DT-00101.
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
5. The sediment basin emergency overflow and outlet pipes will have proper outfall
protection for energy dissipation (i.e., rip-rap protection) prior to discharging into Kings
Creek.
6. The drainage areas for the proposed conditions are designated by the limits of
disturbance boundary. The existing pavement from parking, roadways, roof areas, and
parking areas are considered to be 100% impervious. The typical curve number value
that is utilized for impervious areas is 98 regardless of the underlying hydrologic soil
classification. For the post-development conditions model, we assumed a higher
percentage of impervious area (approximately 80%). Please note that this is a
conservative approach for this phase of the project. The percent (%) impervious areas for
the post development conditions will be refined and evaluated in greater detail during the
next design phase of the project.
7. The post-developed area time of concentration and travel times for each drainage area
are estimated based on the flows generated by the 2-year storm. Any other assumptions
used for the design of the stormwater management plan are discussed in the specific
areas of the report where they apply.
6. Construction Water Management Erosion and Sediment
Control Best Management Practices
The proposed construction activities will occur in multiple phases as discussed in Section 4 -
Construction Schedule. The stormwater management controls shown in the Phase1
construction SWMP is included as Exhibit A in this report. The construction stormwater
management controls shown in the Phase 2 construction stormwater management plan
supports both temporary and operational stormwater management facilities. The Phase-2
SWMP is included as Exhibit B in this report.
The proposed construction activities will utilize the Erosion & Sediment Control (ESC) BMPs
as shown in Exhibits A and B, and as described in this section, to control erosion and
sediment laden runoff from the site before, during, and after earth disturbance activities. The
proposed construction activities will utilize the following ESC BMPs outlined in the stormwater
construction plans to control erosion and sediment-laden runoff from the site before, during,
and after earth disturbance activities. The locations of the ESC BMPs are shown on
Construction Phase 1 and Phase 2 stormwater management plans (Drawings No. KM61-CI-
GA-00105 and Drawings No. KM61-CI-GA-00106). Standard construction erosion and control
details are provided on Drawing No.13 - KM61-CI-DT-001100 and Drawing No.13 - KM61-CI-
DT-001101.
6.1 Rock Construction Entrance
8. Several rock construction entrances (Practice 6.06 of NC ESC Planning and Design
Manual) are proposed at various locations for this project. The location of the stabilized
road entrance is shown Construction Stormwater Management plans. Rock construction
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
entrance details are shown on shown on Erosion & Sediment Control Detail Sheets,
Exhibit-D, Erosion and Sediment Control Detail Sheet, KM61-CI-DT-00100.
6.1.1 Design Standards - Rock Construction Entrance
General design standards followed are those of NCDEQ Bureau of Water Quality Protection.
Minimum design standards include:
1. The aggregate size for construction of the pad shall be American Association of State
Highway and Transportation Officials (AASHTO)#1 rock or equivalent. Place the rock to
the dimensions shown on the detail.
2. The thickness of the pad shall not be less than eight(8) inches. A geotextile fabric will be
used between the rock and existing soils.
3. The width of the pad shall not be less than the full width of all points of ingress or egress
and in any case shall not be less than 20 feet wide.
4. The length of the pad shall be as required, but not less than 50 feet.
5. Topsoil should be removed prior to installation of the rock construction entrance.
6. Runoff shall be diverted from the roadway to a suitable sediment removal BMP prior to
entering the rock construction entrance.
7. A mountable berm should be installed wherever the optional pipe is used. The pipe
should be sized according to the size of the ditch being crossed.
8. The entrance shall be maintained in a condition that will prevent tracking or flowing of
sediment onto public rights-of-way. This may require periodic top dressing with additional
stone as conditions demand, and repair and/or maintenance of any measures used to
trap sediment.
9. All sediment spilled, dropped, washed, or tracked onto public rights-of-way shall be
removed immediately. Washing the roadway or sweeping the deposits into roadway
ditches, sewer, culverts, or other drainageways is not acceptable.
10. All sediment shall be prevented from entering any storm drain, ditch, or watercourse
through use of sand bags, gravel, or other approved methods.
6.1.2 Maintenance - Rock Construction Entrance
Maintain the gravel pad in a condition to prevent mud or sediment from leaving the
construction site (i.e., thickness of the rock construction entrance to be maintained at eight(8)
inches by adding rock, as necessary).
Replace gravel material when surface voids are visible. The thickness of the rock
construction entrance shall be constantly maintained to the specified dimensions by adding
rock. A stockpile shall be maintained on-site for this purpose. If the rock construction entrance
becomes too clogged, it will have to be removed and replaced.
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ALBEMARLE' HATCH
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
After each rainfall, any structure used to trap sediment will be inspected and cleaned out as
necessary.
All objectionable materials spilled, washed, or tracked onto public roadways will be
immediately removed. All sediment deposited on paved roadways within the site limit of
disturbance will be removed within 24 hours. At the end of each construction day, all
sediment deposited on paved roadways shall be removed and returned to the construction
site. Washing the roadway or sweeping the deposits into roadway ditches, sewer, culverts or
other drainageways is not acceptable.
6.2 Diversion Berms
Wedge diversion berms will be utilized to direct flow away from disturbed areas and to the
existing/ proposed stormwater collection systems as shown on the Construction Stormwater
Management plans. The diversion berm details are shown on Erosion & Sediment Control
Detail Sheets (Exhibit-D).
6.2.1 Installation - Wedge Diversion Berms
The diversion berms shall be installed at the locations as shown on the Construction
Stormwater Management plans. Installation will be in accordance with the wedge berm detail
as shown on Erosion & Sediment Control Detail Sheets (Exhibit-D, Erosion and Sediment
Control Detail Sheet, KM61-CI-DT-00100)
6.2.2 Maintenance - Wedge Diversion Berms
Wedge diversion berms should be inspected on a weekly basis and after each runoff event.
Damaged installations shall be repaired or replaced immediately.
6.3 Compost Filter Socks and Sediment Fence
Compost filter socks (Practice 6.66) and or Sediment Fences (Practice 6.62)will be used at
locations downslope of disturbed areas as shown in the construction plans. Compost filter
socks will stay in full contact with the ground surface and thus function to retain sediment in
these areas. The locations of the compost filter socks are shown on the Construction
drawings. Details of the compost filter sock are also provided on shown on Erosion &
Sediment Control Detail Sheets.
Sock fabric shall meet standards of Manufacturer and NC DEQ Erosion Sediment Control
Manual. Traffic shall not be permitted to cross compost filter socks.
Biodegradable compost filter socks shall be replaced after 6 months; photodegradable socks
after 1 year. Polypropylene socks shall be replaced according to manufacturer's
recommendations. Upon stabilization of the area tributary to the sock, stakes shall be
removed and the sock removed from the site. Disposal shall be disposed in a city or NC
DEQ-approved landfill site.
The size of the compost filter sock selected for the locations shown on the drawings is based
on the manufacturer's recommendations (according to the table, shown below). Compost
filter socks shown and described are manufactured by Filtrexx (or approved equal).
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
6.3.1 Design Criteria - Compost Filter Socks
The sedimentation removal process associated with compost filter socks involves both
filtering and deposition from settling. This is different than other methods using only ponding
for deposition of sediment. Ponding occurs when water flowing to the compost filter socks
accumulates faster than it can flow through the sock. Typically, compost filter socks can
handle more water than silt fence. Other Design Considerations are as follows:
Level Contour
Place compost filter socks on level contours to assist in dissipating flow into sheet flow rather
than concentrated flows. Do not construct socks that concentrate runoff or channel water.
Sheet flow of water should be perpendicular to the sock at impact and relatively
unconcentrated.
Flat Slopes
When possible, place socks at a five (5)foot or greater distance away from the toe of the
slopes in order for the water coming from the slopes to maximize space available for
sediment deposit. When this five (5)foot distance is not available due to construction
restrictions, a second row of compost filter socks may be required.
Flow Around Ends
In order to prevent water flowing around the ends of compost filter socks, the ends of the
sock must be constructed pointing upslope at a 45-degree angle so the ends are at a higher
elevation. Be sure to stake the ends of the sock to prevent movement during high flow
events. Socks placed on earthen slopes should be anchored with stakes driven through the
center of the sock at intervals recommended by the manufacturer. When socks are placed on
paved surfaces, rebar shall be used in place of wooden stakes to help hold the sock in place.
Dispersing Flow
Sheet flow and runoff should not exceed height of the sock capacity in most storm events. If
overflow of the sock is a possibility, larger socks should be constructed, or other possible
sediment control tools may be used. Alternatively, a second set of socks may be constructed
or used in combination with compost blankets to prevent sediment from moving.
Slope-Slope Length /Compost Filter Sock Size:
The size of the compost filter sock is dependent on the slope of the ground and the slope
length above the sock. The following table provides the allowable ground slope and slope
length for given sock sizes (source: Filtrexx):
Slope Maximum Slope Length Above Silt Sock(Feet)*
Percent
8" Sock 12" Sock 18" Sock 24" Sock 32" Sock
2 (or less) 600 750 1000 1300 1650
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ALBEMARLE HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Slope Maximum Slope Length Above Silt Sock(Feet)*
Percent
8" Sock 12" Sock 18" Sock 24" Sock 32" Sock
5 400 500 550 650 750
10 200 250 300 400 500
15 140 170 200 325 450
20 100 125 140 260 400
25 80 100 110 200 275
30 60 75 90 130 200
35 60 75 80 115 150
40 60 75 80 100 125
45 40 50 60 80 100
50 40 50 55 65 75
" Based on a failure point of 36-inch super silt fence(wire reinforced)at 1,000 feet of slope,watershed
width equivalent to receiving length of sediment control device, one(1)inch/24 hour rain event.
Fabric Specifications
The fabric used for the compost filter sock shall meet the following minimum specifications
(unless alternate specifications are approved by the Engineer):
Minimum Fabric Specifications
Material Type 3 mil HDPE
Material Characteristics Photo-degradable
Mesh Opening 3/8 inch
Ultraviolet Stability % Original Strength (ASTM G-155) 23% @ 1,000
hours
Functional Longevity six (6) months
Composted Products
The compost used for the compost filter sock shall meet the following minimum specifications
(unless alternate specifications are approved by the Engineer):
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ALBEMARLE HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Minimum Compost Specifications
Organic Matter Content 80% - 100% (dry weight basis)
Organic Portion Fibrous and Elongated
pH 5.5- 8.0
Moisture Content 35% - 55%
Particle Size 98% pass through a one (1) inch
screen
Soluble Salt Concentration 5.0 dS Maximum
6.3.2 Installation— Compost Filter Socks
Compost filter socks will be placed at the locations indicated on the Construction SWMP.
Details of the compost filter sock are shown on Erosion & Sediment Control Detail Sheets.
Compost filter socks should be installed parallel to the base of the slope or other affected
area, perpendicular to sheet flow. Both ends of the compost filter sock shall be extended at
least eight (8)feet up slope at 45 degrees to the main alignment.
Loose compost may be backfilled / placed along the upslope side of the compost filter sock,
filling the seam between the surface and the device, improving filtration and sediment
retention. Traffic shall not be permitted to cross the compost filter socks.
Refer to details on the plan sheet for specifics related to compost filter sock installation.
6.3.3 Maintenance— Compost Filter Socks
The compost filter socks will be inspected weekly and after every stormwater runoff event.
Any necessary repairs will be made immediately. At a minimum, the compost filter socks will
be inspected weekly to ensure that the shape of the compost filter sock is maintained and is
producing adequate flow-through. Damaged compost filter socks shall be repaired according
to the manufacturer's specifications or replaced within 24 hours of inspection. If ponding
upslope of the compost filter socks becomes excessive, additional compost filter socks may
be required to reduce effective slope length.
Accumulated sediment will be removed as required to keep the compost filter sock functional.
In all cases, deposits will be removed when accumulations reach one-half the aboveground
height of the sock. Alternatively, a new compost filter sock may be placed on top of, and
slightly behind, the original compost filter sock creating more sediment storage capacity
without soil disturbance.
Sediment accumulated behind the silt socks will be removed and incorporated into the
grading at the project site. All sediment removed from behind the silt socks, which will not be
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
placed on-site, will be disposed of in a city or NC DEQ-approved landfill site. Manufacturer's
recommendations will be adhered to for replacing silt socks due to weathering.
6.4 Rolled Erosion Control Blankets
Rolled Erosion control blankets (Practice 6.06) are used to temporarily stabilize and protect
disturbed soil from raindrop impact and surface erosion, to increase infiltration, decrease
compaction and soil crusting, and to conserve soil moisture. Mulching with erosion control
blankets will increase the germination rates for grasses and legumes and promote vegetation
establishment. Erosion control blankets also protect seeds from predators, reduce
desiccation and evaporation by insulating the soil and seed environment.
Erosion control blankets aide the establishment of vegetation by reinforcing the soil and
vegetation to resist the forces of erosion during runoff events. Stems, roots, and rhizomes of
the vegetation becomes intertwined with the blanket, reinforcing the vegetation and anchoring
the mat. Erosion control blankets are generally a machine produced mat of organic,
biodegradable mulch such as straw, curled wood fiber(excelsior), coconut fiber or a
combination thereof, evenly distributed on or between photodegradable polypropylene or
biodegradable natural fiber netting. Synthetic erosion control blankets are a machine
produced mat of ultraviolet stabilized synthetic fibers and filaments. The nettings and mulch
material are stitched to ensure integrity and the blankets are provided in rolls for ease of
handling and installation.
Erosion control blankets shall be used on all constructed slopes at the subject site that are
greater than 3H:1 V. The locations of the erosion control blankets are shown on the
Construction Stage drawings. Installation details are shown on Erosion Control Plan -
Construction Details Sheets, Exhibit-D, Erosion and Sediment Control Detail Sheet, KM61-
CI-DT-00101.
6.4.1 Installation -Erosion Control Blankets
Installation of erosion control blankets shall be in accordance with the manufacturer's
recommendations/requirements and/or the following general installation requirements:
1. Proper site preparation is essential to ensure complete contact of the protection matting
with the soil.
2. Grade and shape area of installation. Remove all rocks, clods, vegetative or other
obstructions so that the installed blanket will have direct contact with the soil.
3. Prepare seedbed by loosening two (2)to three (3) inches of topsoil above final grade.
4. Incorporate amendments, such as lime and fertilizer, into soil according to soil test and
the seeding plan.
5. Seed the area before blanket installation for erosion control and re-vegetation. When
seeding prior to blanket installation, all check slots and other areas disturbed during
installation must be reseeded.
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ALBEMARLE' HATCH
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
6. Where soil filling is specified, seed the matting and the entire disturbed area after
installation and prior to filling the mat with soil.
7. U-shaped wire staples, metal geotextile stake pins, or triangular wooden stakes can be
used to anchor mats to the ground surface.
8. Wire staples should be a minimum of 11 gauge. Metal stake pins should be 3/16-inch
diameter steel with a 1-1/2 inch steel washer at the head of the pin. Wire staples and
metal stakes should be driven flush to the soil surface. All anchors should be six (6)to
eight (8) inches long and have sufficient ground penetration to resist pullout. Longer
anchors may be required for loose soils.
9. Begin at the top of the slope and anchor its blanket in a six (6) inch deep x six (6) inch
wide trench. Backfill trench and tamp earth firmly. Unroll blanket downslope in the
direction of the water flow.
10. The edges of adjacent parallel rolls must be overlapped two (2) to three (3) inches and be
stapled every three (3)feet.
11. When blankets must be spliced, place blankets end over end (shingle style)with six (6)
inch overlap. Staple through overlapped area, approximately 12 inches apart.
12. Lay blankets loosely and maintain direct contact with the soil - do not stretch.
13. Blankets shall be stapled sufficiently to anchor blanket and maintain contact with the soil.
Staples shall be placed down the center and staggered with the staples placed along the
edges. Steep slopes, 1 H:1 V to 2H:1 V, require two (2) staples per square yard. Moderate
slopes, 2H:1V to 3H:1V, require one (1)to two (2)staples per square yard (1 staple, 3
feet on center). Gentle slopes require one (1)staple per square yard.
6.4.2 Maintenance—Erosion Control Blankets
All erosion control blankets shall be inspected weekly following installation and after every
rainfall event. Any damaged blanket shall be repaired or replaced immediately.
Inspect installation after significant rainstorms to check for erosion and undermining. Any
failure should be repaired immediately.
If washout or breakage occurs, re-install the material after repairing the damage to the slope
or drainageway.
Any damaged blankets will be disposed of in a city or NC DEQ-approved landfill site.
6.5 Pumps/ Pumped Water Filter Bags
Pumped water filter bags will be utilized whenever excavated areas require dewatering. Filter
bags shall be installed according to the details shown on Erosion & Sediment Control Detail
Sheets.
Low volume filter bags shall be made from non-woven geotextile material sewn with high
strength, double stitched "J"type seams. They shall be capable of trapping particles larger
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
than 150 microns. High volume filter bags shall be made from woven geotextiles that meet
the following standards:
Property Test Method Minimum Standard
Avg. Wide Width Strength ASTM D-4884 60 lb/in
Grab Tensile ASTM D-4632 205 lb
Puncture ASTM D-4833 110 lb
Mullen Burst ASTM D-3786 350 psi
UV Resistance ASTM D-4355 70%
OS % Retained ASTM D-4751 80 Sieve
6.5.1 Installation— Pumped Water Filter Bags
A suitable means of accessing the bag with machinery required for disposal purposes shall
be provided. Filter bags shall be replaced when they become '/z full of sediment. Spare bags
shall be kept available for replacement of those that have failed or are filled. Bags shall be
placed on straps to facilitate removal unless bags come with lifting straps already attached.
Bags shall be located in well-vegetated (grassy) area, and discharge onto stable, erosion
resistant areas. Where this is not possible, a geotextile underlayment and flow path shall be
provided. Bags may be placed on filter stone to increase discharge capacity. Bags shall not
be placed on slopes greater than 5%. For slopes exceeding 5%, clean rock or other non-
erodible and non-polluting material may be placed under the bag to reduce slope steepness.
The pump discharge hose shall be inserted into the bags in the manner specified by the
manufacturer and securely clamped. A piece of PVC pipe is recommended for this purpose.
The pumping rate shall be no greater than 750 gpm or'/z the maximum specified by the
manufacturer, whichever is less. Pump intakes shall be floating and screened.
6.5.2 Maintenance—Pumped Water Filter Bags
A suitable means of accessing the bag with machinery required for disposal purposes shall
be provided. Pumped water filter bags shall be replaced when they become '/2 full of
sediment.
Spare bags shall be kept available for replacement of those that have failed or are filled. It is
recommended that pumped water filter bags be placed on straps to facilitate removal unless
bags come with lifting straps already attached. Pumped water filter bags shall be inspected
daily.
If any problem with the pumped water filter bag is detected, pumping shall cease immediately
and not resume until the problem is corrected. All spent pumped water filter bags will be
disposed in a city or NC DEQ-approved landfill site.
6.6 Sediment Ponds
Sediment protection will be provided by constructing sediment control ponds (Practice 6.61)
that will receive non-contact water flows from disturbed and undisturbed natural ground
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
collected by the perimeter channels as shown in the construction plans. The sediment ponds
will discharge directly to Kings Creek. Where appropriate, temporary sediment traps will be
installed, to service areas less than 5 acres, for up to one year. The storage capacity of the
traps will be at least 1,800 cubic feet(ft3) of storage per disturbed acre of drainage area and
will safely pass the 10-year, 24-hour design storm for the total drainage area. Skimmers can
be installed in each of the sediment ponds to discharge clear water from the ponds.
6.6.1 Maintenance— Sediment Ponds
All sediment ponds, seepage ponds, check dams, and silt curtains will be checked for stability
and operation in accordance with the standard practices outlined in the latest version of NC
ESC design and planning manual. Any needed repairs or adjustments will be implemented
immediately. Inspect installation after significant rainstorms to check for erosion and
undermining. Any failure should be repaired immediately.
6.7 Rip-Rap Channels
Rip-rap lined channels (Practice 6.31)will be required to provide adequate erosion resistance
to convey runoff to the sediment basins and outfall structures. Some of these channels may
require armoring (as shown in Exhibit E) depending on the velocities. Riprap channels will be
designed to contain the peak runoff from the 10-year storm as a minimum. in accordance with
the standard practices outlined in the latest version of NC ESC design and planning manual.
6.8 Dust Control
Haul traffic on dirt roads during construction activities will require regular application of water
for dust control (Practice 6.84). Air monitoring will be implemented at the site to evaluate the
effectiveness of the dust control and adjust sprinkling application rates as necessary to meet
Mine Safety and Health Administration (MSHA)guidelines.
6.9 Temporary Seeding
Temporary seeding (Practice 6.1) is used to protect earthen sediment control practices and to
stabilize denuded areas that will not be brought to final grade for several weeks or months.
Temporary seeding can provide a nurse crop for permanent vegetation, provide residue for
soil protection and seedbed preparation, and help prevent dust during construction.
Temporary seeding provides protection for no more than 1 year, during which time permanent
stabilization should be initiated.
All disturbed areas that have not otherwise been stabilized and have significant potential for
erosion shall be stabilized with vegetation in accordance with the standard practices (6.10
through 6.11)outlined in the latest version of NC ESC design and planning manual. This
includes graded areas where it is anticipated that future earth disturbance will take place
within the coming year. Areas that will be subject to earth disturbance within 12 months may
be stabilized with temporary seed mixtures (predominantly annual grasses). All others
should be stabilized with permanent seed mixtures (predominantly perennial grasses). When
final grade is achieved during non-germinating months, the area should be mulched until the
beginning of the next planting season. However, the area will not be considered stabilized
until a minimum uniform 70 percent vegetative cover of erosion resistant perennial species
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
has been achieved. Critical areas (erodible soils, within 50 feet of a surface water, etc.)
should be blanketed. Temporary ESC BMPs that were installed for the earth disturbance
phase of the project must remain in place and be maintained in working order until permanent
stabilization is achieved. Note, areas that do not receive sufficient sunlight to support
vegetation (e.g., under bridge decks) should be stabilized by some means other than
vegetation.
As disturbed areas within a project approach final grade, preparations should be made for
seeding and mulching to begin (i.e., anticipate the completion date and schedule the seeder).
In no case should an area exceeding 15,000 square feet, which is to be stabilized by
vegetation, reach final grade without being seeded and mulched. Waiting until earth
disturbance is completed before making preparations for seeding and mulching is not
acceptable. This requirement should be clearly stated in the seeding and mulching
specifications contained on the plan drawings.
Before the seeding begins, topsoil should be applied, and any required soil amendments
worked into the soil to a depth of six (6) inches. If compost is to be added to the topsoil, it
should be worked into the soil with the other soil amendments unless it is being applied as an
erosion control BMP.
6.9.1 Topsoil Application
Graded areas should be scarified or otherwise loosened to a depth of three (3)to five (5)
inches to permit bonding of the topsoil to the surface areas and to provide a roughened
surface to prevent topsoil from sliding down slope. Topsoil should be uniformly distributed
across the disturbed area to a depth of six (6) inches minimum. Spreading should be done in
such a manner that sodding or seeding can proceed with a minimum of additional preparation
or tillage. Irregularities in the surface resulting from topsoil placement should be corrected in
order to prevent formation of depressions.
Topsoil should not be placed while the topsoil or subsoil is in a frozen or muddy condition,
when the subsoil is excessively wet, or in a condition that may otherwise be detrimental to
proper grading and seedbed preparation.
6.9.2 Seed Mixtures
Depending on the time of the year, seed mixtures for the project are outlined in Table 6.10a,
Table 6.10b and Table 6.10c of the NC ESC design and planning manual.
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AALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Table 6.10a Seeding mixture
Temporary Seeding Species Rate (lb/acre)
Recommendations for Late Rye(grain) 120
Winter and Early Spring Annual lespedeza (Kobe in
Piedmont and Coastal Plain,
Korean in Mountains) 50
Omit annual lespedeza when duration of temporary cover is not to
extend beyond June.
Seeding dates
Mountains—Above 2500 feet: Feb. 15-May 15
Below 2500 feet: Feb. 1- May 1
Piedmont—Jan. 1 -May 1
Coastal Plain—Dec. 1 -Apr. 15
Soil amendments
Follow recommendations of soil tests or apply 2,000 Iblacre ground
agricultural limestone and 750 Iblacre 10-10-10 fertilizer.
Mulch
Apply 4,000 Iblacre straw. Anchor straw by tacking with asphalt,netting,
or a mulch anchoring tool. A disk with blades set nearly straight can be
used as a mulch anchoring tool.
Maintenance
Refertilize if growth is not fully adequate. Reseed, refertilize and mulch
immediately following erosion or other damage.
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AALBEMARLE' HUTCH
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Table 6.10b Seeding mixture
Temporary Seeding Species Rate (Ibfacre)
Recommendations for German millet 40
Summer
In the Piedmont and Mountains, a small-stemmed Sudangrass may be
substituted at a rate of 50 lb/acre.
Seeding dates
Mountains—May 15-Aug. 15
Piedmont—May 1 -Aug. 15
Coastal Plairw—Apr. 15 -Aug. 15
Soil amendments
Fallow recommendations of soil tests or apply 2,000 lb/acre ground
agricultural limestone and 750 Ibfacre 10-10-10 fertilizer.
Mulch
Apply 4,000 Ibfacre straw. Anchor straw bytacking with asphalt, netting,
or a mulch anchoring tool. A disk with blades set nearly straight can be
used as a mulch anchoring tool,
Maintenance
Refertilize if growth is not fully adequate. Reseed, refertilize and mulch
immediately following erosion or other damage.
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AALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Table 6.10c Seeding mixture
Temporary Seeding Species Rate(lb/acre)
Recommendations for Fall Rye(grain) 120
Seeding dates
Mountains—Aug. 15- Dec. 15
Coastal Plain and Piedmont—Aug. 15-Dec.30
Soil amendments
Follow soil tests or apply 2,000 lb/acre ground agricultural limestone
and 1,000 Nacre 10-10-10 fertilizer.
Mulch
Apply 4,000 Ib/acre straw. Anchor straw by tacking with asphalt,netting,
or a mulch anchoring tool. A disk with blades set nearly straight can be
used as a mulch anchoring tool.
Maintenance
Repair and refertilize damaged areas immediately. Topdress with 50
Iblacre of nitrogen in March. If it is necessary to extent temporary
cover beyond June 15, overseed with 50 Nacre Kobe (Piedmont and
Coastal Plain) or Korean (Mountains) lespedeza in late February or
early March.
Seeding rate shall be in accordance with the supplier's recommended application rate.
Utilize erosion control blankets for all seeded areas on slopes steeper than 3H:1 V. Soil
testing may be done prior to seeding and mulching to determine the proper soil amendments
and application rates for the proposed seed mixture(s). In the absence of a soil test, soil
amendments will be added at the rates specified by the selected seeding reference (see
below).
6.10 Inlet Protection
Inlet protection (Practices 6.50 through 6.55)will be provided at all inlets/catch basins on
existing (Holiday Inn Dr.)and proposed road that are downgradient of disturbed areas. The
locations of inlet protection are shown on the Construction Phase drawings. Inlet protection
details are shown on Erosion Control Plan - Construction Details Sheets. Due to the
variations in inlet/catch basin types across the project site, several types of inlet protection
are proposed for the project. The contractor shall be responsible for determining the specific
inlet protection detail required at each inlet/catch-basin.
The following is a general discussion for inlet protection:
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
6.10.1 Installation -Inlet Filter Bags
Wherever filter bags are used they should be installed according to the manufacturer's
specifications and the standard practices (6.50 through 6.55)outlined in the latest version of
NC ESC design and planning manual. NOTE: Filter bags designed to fit over the inlet grate
are not recommended for most storm sewer inlets. Use of such filter bags could result in a
severe reduction of the inlet capacity resulting in flooding or runoff bypassing the inlet.
Wherever such bags are used, they should be located at topographic low points and limited
to '/4 acre maximum drainage areas. Inlet filter bags are not acceptable as the primary BMP
to remove sediment from site runoff water.
6.10.2 Maintenance—Inlet Filter Bags
Inlet filter bags should be inspected on a weekly basis and after each runoff event. Filter bags
should be cleaned and/or replaced when the bag is half full or when flow capacity has been
reduced so as to cause flooding or bypassing of the inlet.
All sediment removed from inlet filter bags, which will not be placed on-site, will be disposed
of in a city or NC DEQ-approved landfill site.. Inlet filter bags shall not be re-used. Damaged
filter bags should be replaced. Needed repairs should be initiated immediately after the
inspection.
6.10.3 Installation— Stone Inlet Protection
Wherever stone and/or stone and concrete block inlet protection is proposed, it should be
installed according to the standard practices (6.50 through 6.55) outlined in the latest version
of NC ESC design and planning manual. This type of inlet protection should not be used
where ponding of water would cause a traffic hazard.
6.10.4 Maintenance— Stone Inlet Protection
Stone inlet protection should be inspected on a weekly basis and after each runoff event.
Sediment shall be removed when it reaches half the height of the stone. Damaged or clogged
installations shall be repaired or replaced immediately. All stone and sediment removed from
inlet, which will not be placed on-site, will be disposed of at a city or NC DEQ-approved
landfill site.
7. Construction Sequence for Erosion and Sediment Control
Best Management Practices
For work related to earth disturbance, the primary consideration for preventing sediment
release is the sequence and timing of operations. All BMPs shall be installed in accordance
with the standard details provided in this plan, including latest version of the North Carolina
ESC planning and design manual. The proposed construction activities will utilize various
ESC BMPs outlined in the stormwater construction plans to control erosion and sediment-
laden runoff from the site before, during, and after earth disturbance activities. The locations
of the ESC BMPs are shown on Construction Phase 1 and Phase 2 stormwater management
plans (Drawings No. KM61-CI-GA-00105 and Drawings No. KM61-CI-GA-00106). Standard
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
construction erosion and control details are provided on Drawing No.13 - KM61-CI-DT-
001100 and Drawing No.13 - KM61-CI-DT-001101.
A general sequence of construction activities is listed below:
1. Set up construction staging/laydown areas and use existing roads as identified on the
plans to access project areas. Install temporary construction fence around the access
roads as shown in the plans.
2. Field mark limits of disturbance areas.
3. Install wedge diversion berms as shown on the plan.
4. Install compost filter socks or silt fence as shown on the plan.
5. Install rock construction entrances as indicated on the plans.
6. Install erosion control blankets on slopes greater than three units horizontal for each one
unit vertical (31-1:1 V).
7. As disturbed areas reach final line and grade immediately place topsoil, revegetate with
approved seed mixture, and mulch.
8. Dewater work areas as necessary, utilizing sediment ponds, skimmers, pumps, or other
approved devices as shown in the plans.
As construction activities commence/continue through the life of the project, existing ESC
features will be evaluated for effectiveness. All damaged ESC features will be repaired or
replaced, as necessary. Under no circumstances shall ESC BMPs be used for temporary
storage of demolition materials or construction wastes.
8. Sediment and Erosion Control Inspection and Maintenance
Procedures, Operation and Maintenance Plan
The &SC BMPs shown on the plans are designed to manage stormwater runoff during
construction activities by collecting and filtering sediment-laden runoff from the disturbed
areas and/or reducing runoff by the revegetation of disturbed areas. This section details the
anticipated inspection, operation, and maintenance (O&M) of activities for the temporary ESC
measures and BMPs implemented at the project site. The program provides completion of a
written report documenting each inspection and all BMP repair or replacement activities.
Regular maintenance practices are critical to prevent any adverse negative impacts to the
environment. Routine inspections of all ESC facilities will be conducted at least once a week
and after every rainfall event that results in observable runoff on a regular basis and after
each stormwater event, including the repair or replacement of BMPs to ensure effective and
efficient operation. An inspection report template will be prepared.
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
8.1 Inspection Schedule
All ESC BMPs at the construction sites shall be inspected on a weekly basis and after each
stormwater runoff event. The contractor shall maintain an inspection log which documents the
BMPs which were inspected, their condition, and any needed repairs/replacements. The
inspection log shall also note any corrective actions taken as a result of the inspection. The
inspection log shall be kept on site and available at any time for review by the City of Kings
Mountain (city) and/or NCDEQ representative. All sediment removed from any ESC BMP,
which will not be placed on-site, will be disposed in a NC DEQ-approved landfill or a city
approved soil/rock disposal area.
The log shall contain the following items:
• Maximum sediment storage elevation/level in BMP's.
• The maximum sediment storage elevation/level in each ESC BMP is listed in the
maintenance section below.
• Disposal directions for sediment removed from BMPs.
8.2 ESC BMP Maintenance Requirements
8.2.1 Maintenance—Inlet Filter Bags
Inlet filter bags should be inspected on a weekly basis and after each runoff event. Filter bags
should be cleaned and/or replaced when the bag is half full or when flow capacity has been
reduced so as to cause flooding or bypassing of the inlet.
• All sediment removed from inlet filter bags, which will not be placed on-site, will be
disposed of in a NCDEQ-approved landfill or a city approved soil/rock disposal area.
• Inlet filter bags shall not be re-used.
• Damaged filter bags should be replaced.
• Needed repairs should be initiated immediately after the inspection.
8.2.2 Maintenance— Stone Inlet Protection
Stone inlet protection should be inspected on a weekly basis and after each runoff event.
Sediment shall be removed when it reaches half the height of the stone. Damaged or clogged
installations shall be repaired or replaced immediately.
All stone and sediment removed from inlet, which will not be placed on-site, will be disposed
in a NCDEQ-approved landfill or a city approved soil/rock disposal area.
8.2.3 Maintenance—Diversion Berms
Diversion berms should be inspected on a weekly basis and after each runoff event.
Damaged installations shall be repaired or replaced immediately.
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
8.2.4 Maintenance—Rock Construction Entrance/Exit
Maintain the gravel pad in a condition to prevent mud or sediment from leaving the
construction site (i.e., thickness of the rock construction entrance to be maintained at eight(8)
inches by adding rock, as necessary).
• Replace gravel material when surface voids are visible. The thickness of the rock
construction entrance shall be constantly maintained to the specified dimensions by
adding rock. A stockpile shall be maintained on-site for this purpose. If the rock
construction entrance becomes too clogged, it will have to be removed and replaced
immediately.
• After each rainfall, any structure used to trap sediment will be inspected and cleaned out,
as necessary.
• All objectionable materials spilled, washed, or tracked onto public roadways will be
immediately removed. All sediment deposited on paved roadways within the site limit of
disturbance will be removed within 24 hours.
• At the end of each construction day, all sediment deposited on paved roadways shall be
removed and returned to the construction site. Washing the roadway or sweeping the
deposits into roadway ditches, sewer, culverts or other drainageways and or waterways is
not acceptable.
8.2.5 Maintenance— Compost Filter Socks/Sediment Silt Fence
The compost filter socks/sediment fence will be inspected weekly and after every stormwater
runoff event. Any necessary repairs will be made immediately. At a minimum, the compost
filter socks/sediment fence will be inspected weekly to ensure that the shape of the compost
filter sock is maintained and is producing adequate flow-through. Damaged compost filter
socks/sediment fence shall be repaired according to the manufacturer's specifications or
replaced within 24 hours of inspection.
• If ponding upslope of the compost filter socks/sediment fence becomes excessive,
additional compost filter socks/sediment fence may be required to reduce effective slope
length.
• Accumulated sediment will be removed as required to keep the compost filter sock and
fence functional. In all cases, deposits will be removed when accumulations reach one-
half the aboveground height of the sock. Alternatively, a new compost filter sock/fence
may be placed on top of, and slightly behind, the original compost filter sock creating
more sediment storage capacity without soil disturbance.
• Sediment accumulated behind the silt socks will be removed and incorporated into the
grading at the project site.
• All sediment removed from behind the silt socks, which will not be placed on-site, will be
disposed in a NCDEQ-approved landfill or a city approved soil/rock disposal area.
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
• Manufacturer's recommendations will be adhered to for replacing silt socks due to
weathering.
8.2.6 Maintenance—Pumped Water Filter Bags
A suitable means of accessing the bag with machinery required for disposal purposes shall
be provided.
• Pumped water filter bags shall be replaced when they become half full of sediment.
• Spare bags shall be kept available for replacement of those that have failed or are filled.
• It is recommended that pumped water filter bags be placed on straps to facilitate removal
unless bags come with lifting straps already attached.
• Pumped water filter bags shall be inspected daily.
• If any problem with the pumped water filter bag is detected, pumping shall cease
immediately and not resume until the problem is corrected.
• All spent pumped water filter bags will be disposed in a city or NCDEQ-approved landfill
facility.
8.2.7 Maintenance— Rolled Erosion Control Blankets
All erosion control blankets shall be inspected weekly following installation and after every
rainfall event. Any damaged blanket shall be repaired or replaced immediately.
• Inspect installation after significant rainstorms to check for erosion and undermining. Any
failure should be repaired immediately.
• If washout or breakage occurs, re-install the material after repairing the damage to the
slope or drainageway.
• Any damaged blankets will be disposed in a NCDEQ-approved landfill or a city-approved
landfill.
8.2.8 Maintenance—Rip-Rap Channels/Rock Check Dams
Riprap channels and check dams will be inspected after every major storm event for
displaced stones, slumping, and erosion at edges, particularly in steeper segments. Woody
vegetation will be removed from the riprap regularly to avoid potential impacts associated with
the roots, such as dislodgement of the rocks.
• Repair ditch/channel areas where excessive downcutting or side scour have occurred.
• Remove sediment adjacent to and accumulated behind rock check dams before it
reaches halfway to the top of the dam.
• Make note of whether the selected configuration is preventing channel erosion. If not,
make necessary changes to the design, considering other materials or closer spacing in
areas experiencing the most problems.
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
• Restore dislodged or washed-out check dams to their original configuration. Fill in or
otherwise repair areas where check dam undercutting or bypasses have occurred.
• Add stones to dams as needed to maintain design height and cross section. Use larger
stone, if necessary, to counter higher-than-expected flow velocities.
• If significant erosion is observed between dams, install a protective turf reinforcement mat
or section of riprap liner in that portion of the channel.
• Replace rock weirs when filtering capacity is reduced by one-half.
8.2.9 Maintenance— Sediment Ponds
All sediment ponds, seepage ponds, check dams, and silt curtains will be checked for stability
and operation. Any needed repairs or adjustments will be implemented immediately. Inspect
installation after significant rainstorms to check for erosion and undermining. Any failure
should be repaired immediately.
• Ponds will be cleaned out when the sediment accumulation reaches 50% of the available
storage.
• If the sediment accumulation in the sediment basin exceeds 75% of capacity before they
are scheduled for removal, ponds will be cleaned out. For each facility the cleanout level
will be pre-determined in the inspection report.
• Floating trash and debris will be removed.
• Unwanted vegetation at the top and faces of the embankment will be removed.
• All outlet structures from the sediment ponds will be inspected for clogging and/or
structural damage. Debris will be removed, and any repairs needed will be done
immediately.
• Outflow locations will be inspected to make sure tailwater conditions are not impeding
discharge from the pond.
8.2.10 Material Recycling and Disposal
Recycling and disposal of materials procedures ensure that the proper measures for the
recycling or disposal of materials associated with or from the project site will be undertaken,
as follows:
• Waste management— building materials and other construction site wastes shall be
properly managed and disposed of to reduce potential for pollution to surface and ground
waters. Proper trash disposal, recycling of materials, proper materials handling, and spill
prevention and clean-up reduce the potential for construction site wastes to be mobilized
by stormwater runoff and conveyed to surface waters.
• Recyclable materials which may be generated by construction activities include concrete
and asphalt, piping, inlet grates, manhole covers, and aggregates. Recyclable materials
will be stockpiled on site upslope of ESC BMP's. Vehicles removing the recyclable
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ALBEMARLE' HATCH
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
materials shall utilize the site's rock construction entrance if access is through a disturbed
area. Recyclable materials shall be stockpiled on paved areas where there is no potential
for soil/mud to be tracked across the site or onto public roads and may be removed from
the site via existing driveways.
• Under no circumstances shall erosion control BMPs be used for temporary storage of
demolition materials or construction wastes.
• Wherever heavy equipment will be used during construction of the cuts and fills or
proposed buildings, a pollution prevention contingency (PPC) plan shall be available on
site.
• All applicable federal, state, and local laws and regulations shall be followed in the use,
handling, and disposal of potentially hazardous materials.
• Soil materials will be removed from the site as part of the general construction activities.
The contractor shall be responsible for obtaining all appropriate permit approvals
including a National Pollutant Discharge Elimination System (NPDES) Permit for
Stormwater Discharges Associated with Construction Activities for the selected soil/rock
disposal locations. Proof of such approvals shall be provided to the NCDEQ or the city
representative prior to the start of construction activities at the project site.
9. Water Quality Monitoring Program
Although there are not specific quantitative monitoring requirements, regular visual
assessment shall be conducted to ensure that the BMPs are effective. To complete a visual
assessment, a collect a sample in a clean, colorless glass or plastic container.
Visually inspect the sample for the following water quality characteristics, which may be
evidence that BMPs are not working effectively:
• Color,
• Odor,
• Diminished clarity,
• Floating, settled, or suspended solids,
• Oil sheen,
• Foam, and
• Other obvious indicators of stormwater pollution.
Record the visual observations and take photographs of the discharges at the time of
observation to help determine the effectiveness of the BMPs.
For anything but colorless and odorless stormwater in the discharge, investigate the area
contributing to the discharge to determine the source of the pollutant.
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ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Clean up any potential sources of potential contamination. Evaluate and modify BMPs to
prevent a recurrence.
10. Adaptive Management
Adaptive stormwater management promotes flexible decision making that can be adjusted in
the face of changing conditions or unexpected events, which could include extreme weather
conditions and spills. These sorts of issues and concerns will be addressed on a case-by-
case basis. Appropriate personnel will be consulted to determine the best course of action.
This CSMP will be updated as needed based on these events.
11. References
Hatch, December 2023, Preliminary Drainage Analysis Report for the NPI, Ore Mining and
Process Areas, Kings Mountain Mine Facility, Cleveland County, NC.
Hatch, January 2024, Civil Design Criteria.
North Carolina Sedimentation Control Committee, North Carolina Department of
Environmental and Natural Resources, and the North Carolina Agricultural Extension Service,
May 2013. Erosion and Sediment Control Planning and Design Manual.
SRK Consulting, Inc., September 2023. Surface Water Management Report— Kings
Mountain.
Soils Data from Web Soil Survey (WSS), USDA Natural Resources Conservation Service
(NRCS)
State of North Carolina, Department of Environment, Health and Natural Resources,
February 1996, Surface MINING Manual.
SWCA, 2022. Wetland and Waterbody Delineation Report for the Albemarle Kings Mountain
Lithium Mining Project, Cleveland County, North Carolina.
Trinity Consultants, May 2021. Stormwater Pollution Prevention Plan (SWPPP).
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Page 35
©Hatch 2024 All rights reserved,including all rights relating to the use of this document or its contents.

ALBEMARLE" HUTCH
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Exhibit A:
Phase 1 - Construction Stormwater
Management Plan
H371132-4000-220-230-0001, Rev. C
©Hatch 2024 All rights reserved,including all rights relating to the use of this document or its contents.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
TCF LEGEND:
(TYP.) S. BATTLEGROUND AVE.
PERIMETER RIP-RAP , i� PROPOSED TOE OF FILL SLOPE A
CHANNEL (TYP.) �% i� � ��� _
PROPOSED TOP OF CUT SLOPE
I
FLOW PATH
POND OUTLET PIPE
� DEVELOPMENT PHASE BOUNDAR
DISCHARGE TO
PHASE 3B /��� EXISTING GROUND — — —
t LIMITS OF DISTURBANCE
OVERBURDEN POND OUTLET PIPE �� I /��� (LOD)
STOCKPILE \\ DISCHARGE TO
FACILITY EXISTING CULVERT PHASE-3A f
�� �� --- C) (AREA=63 AC.) STOCKPILE I GROWTH MEDIA ----
J � ROCK CONSTRUCTION
(OSF-1)
/ t ENTRANCE & EXIT
SEDIMENT I I t (PRACTICE 6.06)
POND 3A I I
t EROSION CONTROL
BLANKET PRACTICE 6.17
SUPER SILT FENCE/COMPOST
TCF ��- �� �` / t - FILTER SOCK CFS
� , ? `r — ®t �/ SEDIMENT ( )
(TYP.) i PROPOSED 18" > PROPOSED 18 I_ �' POND 3B (PRACTICE 6.66.6.62)
/ CULVERT,` - �/ CULVERT 11
\ \\ / SEDIMENT BASIN WITH SKIMMER
CFS ;�_ - __ ��'/ \ POND OUTLET PIPE
1 �\ i OSF SEDIMENT (TYP.) �� _� PRACTICE 6.61
POND 1 / , - _ DISCHARGE TO ( )
/ �__ r _ , ___- EXISTING GROUND D
/ - - NOTE: STORMWATER ENTERING THE
-- RIPRAP LINED CHANNEL
PROPOSED 18" OPEN PIT IS DISCHARGED VIA (PRACTICE 6.21)
/ -_- - /
- I /j CULVERT PUMPS AS PER NPDES PERMIT
OVERBURDEN tt t1 PERIMETER RIP-RAP ���"�� OUTLET PROTECTION LEVEL
SPREADER (PRACTICE 6.4)
STOCKPILE tt t CHANNEL (TY.
------ DIVERSION BERM
SOUTH j �� ��( FACILITY (OSF-2)
t / CREEK / ,' / i�� V�� I 1 �'� (TYPFS ) DRAINAGE AREA
PIT PUMP AND PIPING E
� CONTRIBUTING TO
CULVERT 24-INCH CULVERT TEMPORARY CONSTRUCTION
DISCHARGE (5.7 ACRES) FENCE (TCF)
CULVERT DRAIN
/ I p RSF-A �. I INSTALL 24"
SRK ROAD _ STORMWATER l r /// / \�\���\ I CULVERT „ F
COLLECTION
CHANNEL \ / / ��� �� T-]
\ DITCH , RSF-X
SOUTH CREEK i / �,
STORMWATER �� , SEDIMENT
COLLECTION ��� �i POND n
DITCH
TIN MINE ROADo G
���� j� ��
/
RSF-X
POND OUTLET PIPE
DISCHARGE TO ;
KINGS CREEK 1
l EXISTING STORM
DRAINAGE FEATURE
CFS(TYP n
TECH CENTER
SEDIMENT POND WRC-61 �.�\ �� � / � � �, �' -
___
PROPOSED 24" / _1t� �� — ----- ____________ _ -------- RECB _ ---- -- __-- _RECB \
s
RECB
CULVERT \ �� .�_ \ ��_---- --- ---______________
_ - --
^SOUTH CREEK PHASE-1A I SEDIMENT
- \� t POND Al �� I SEDIMENT ���� HOLIDAY INN DRIVE
RESERVOIR ap I
PERIMETER RIP--RAP � � — / SEDIMENT POND A5 V 1 _
POND w 1 SEDIMENT
CHANNEL (TYP.) ��- -__ __- -l� WRC-51 11 POND A2 �_ PHASE-1 B SEDIMENT (AREA S21 1AC.)
--_ POND OUTLET PIPE DISCHARGE SEDIMPONDENT I A3 4■ ------------- (AREA=27.5 AC.) 1
OSF SEDIMENT TO SOUTH CREEK POND A4
OVERBURDEN STOCKPILE POND 3 POND OUTLET PIPE DISCHARGE _ __ __ __ _ _- --_-__------ 1� --- ------------
FACILITY OSF-3 TO SOUTH CREEK POND OUTLET PIPE POND-- 1 - RECB =_- - RECB __________________ ___ __ __________________----------------
DISCHARGE
TO
KINGS CREEK EC,P ) ��,P ) 1-85
--- -------1 --- _ _ K
KINGS CREEK ' I ,j INDUSTRIAL DRIVE
PHASE-2A 1
1
POND OUTLET PIPE ,� SEDIMENT PHASE-2B � (AREA=38.5 AC.)
DISCHARGE TO 1 POND 131 (AREA=13.4 AC.) \ \\\ 1
Z_ KINGS CREEK �� 1
L
SEDIMENT SEDIMENT/r' 1 1
MISC. WASTE ��_ \ ��\ POND B2 POND B3 l
STORAGE
- TOE OF -- INN-
----- I j
POND OUTLET PIPE 1 SLOPE
�- DISCHARGE TO �---- 1 -_----------------- — - -t
KINGS CREEK
KINGS CREEK -
� POND-CO2 �- �� � - -
( / POND OUTLET PIPE -_
i POND OUTLET PIPE - - ,�- _
11 DISCHARGE TO
_J_ J� EXISTING GROUND
DISCHARGE TO '� � WATER STORAGE _
J EXISTING GROUND �
( � - BASIN WSB-1 �
- i
r ----------------------------
-----------------
SEE ENLARGED DRAWING NUMBER t N
(H371132-5200-222-270-0002) FOR - -
I _ ------ CONSTRUCTION STORMWATER MANAGEMENT
L� -- PLAN FOR DUKE'S SUBSTATION PAD
GALILEE CHURCH
ROAD
OVERALL SITE DRAINAGE PLAN
SCALE: 1"=400'-O" �YORK ROAD P
HL\TCH ___
-- ALBEMARLETM KINGS MOUNTAIN
DRAFTSPERSON E. MOPENO NR 03 18 24 -- ___ C 0 R P 0 R A T 1 0 N 348 HOLIDAY INN DRIVE
DESIGNER E. MOPENO NR 03 1 8 24 --- --- KINGS MOUNTAIN, NC 28286
CHECKER S. ALUGUVELU This drawing is the confidential property of Albemarle Corporation and is issued with the express understanding and agreement that it
DESIGN COORD. T. KAISER --- is not to be copied or reproduced,or used in any way detrimental to the interest of Albemarle Corporation and is to be returned on request.
ISSUED F 0 R PERMITTING RESP. ENG. S ALUGUVE2u --- ___ MINING AND CONCENTRATOR FACILITY
LEAD DISC. ENG. S. ALUG_V-2u MINE SELECT PHASE
ENG. MANAGER PHASE 1 CONSTRUCTION
NOT FOR CONSTRUCTION PROD. MANAGER K HUNG C ISSUED FOR PERMITTING
ELM SRA TPK 07/11/24 STORMWATER PLAN
ROLE NAME SIGNATURE DATE B ISSUED FOR PERMITTING ELM SRA TPK 04/03/24 JOB NO. DRAFTER: DRAWING NO. SHT. 1 of 1 REVISION R
INTERNAL&CLIENT REVIEW KM22040 E. MORENO
A ELM SRA TPK 03/29/24 KM61 —Cl-GA-00105 C
HATCH DRAWING NUMBER: H371132-4000-222-270-0003 --- SCALE DATE
REV# DESCRIPTION CADD CHK'D APPR'D DATE AS NOTED 03/18/24

ALBEMARLE' HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Exhibit B:
Phase 2 - Construction Stormwater
Management Plan
H371132-4000-220-230-0001, Rev. C
©Hatch 2024 All rights reserved,including all rights relating to the use of this document or its contents.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
♦% ��� TCF
S. BATTLEGROUND AVE. LEGEND.
PERIMETER RIP-RAP ♦ / `���'��� PROPOSED TOE OF FILL SLOPE A
CHANNEL (TYP.) - PROPOSED TOP OF CUT SLOPE
FLOW PATH
_ POND OUTLET PIPE
PHASE 3B / DISCHARGE TO — — — DEVELOPMENT PHASE BOUNDAR
EXISTING GROUND
\ B
1 \ OVERBURDEN \ \ 1 �i LIMITS OF DISTURBANCE
\ \ \ POND OUTLET PIPE 1 �/� (LOD)
SFAOCILITYCK E DISCHARGE TO
\ \ EXISTING CULVERT PHASE-3A �� GROWTH MEDIA i �'_
(OSF-1) \ \�\\ --- Q (AREA=63 AC.) 1 STOCKPILE -- ROCK CONSTRUCTION
V 1 ) 1 - ENTRANCE & EXIT
SEDIMENT I I j
1 (PRACTICE 6.06)
1 POND 3A
EROSION CONTROL C
1 I 1 O BLANKET (PRACTICE 6.17)
1 '
OSF SEDIMENT �1% �— \
\`\ SUPER SILT FENCE/COMPOST
POND 1A 1
TCF �� ♦ I� 1 — � FILTER SOCK CFS
� � � ♦ I � SEDIMENT (CFS)
(TYP.) j PROPOSED 18 � � ® i�
PROPOSED 18 I .01
POND 36 (PRACTICE 6.66.6.62)
CULVERT CULVERT — i � If
CFS �� ��� �♦ / POND OUTLET PIPE SEDIMENT BASIN WITH SKIMMER
OSF PONDS SEDIMENT (TYP ); `�����===♦ \ PRACTICE 6.61
/ e \/ �_ �� \ DISCHARGE TO ., ( ) D
EXISTING GROUND -
NOTE: STORMWATER ENTERING THE
-- RIPRAP LINED CHANNEL
1 OPEN PIT PROPOSED 18" (PRACTICE 6.21)
CULVERT
�` PUMPS AS IS
DISCHARGED
NPDESG PDERMIT
OVERBURDEN PERIMETER RIP-RAP !ii� OUTLET PROTECTION LEVEL
/ / I SPREADER (PRACTICE 6.4)
1 STOCKPILE CHANNEL (TYP.)
1
- --------- DIVERSION BERM
SOUTH FACILITY (OSF-2) N
1 CFS DRAINAGE AREA PIT PUMP AND PIPING
CREEK /�N���/�/ \ (TYP CONTRIBUTING TO E
I CULVERT /� /� ` 1 I r- 24-INCH CULVERT TEMPORARY CONSTRUCTION
1 DISCHARGE (5.7 ACRES) FENCE (TCF)
1 % !SF-A' '��i/ // \ �`�
_ 0 CULVERT DRAIN
. , /o of J / /♦ /f j / RS�F-X�/�
� FRENCH DRAIN RSF-A
G I INSTALL 24"
STORMWATER
CULVERT
CHANNEL
SRK ROAD COLLECTION
DITCH STORM SEWER/OUTLET
/i o
\ SOUTH CREEK - / � ♦ ♦ STRUCTURE
// STORMWATER \ %N �__-♦ ♦ ♦ SEDIMENTSz
\ COLLECTION �� �� POND
DITCH .� ♦ ��
V A�
TIN MINE ROAD �
1
G
�� OSF SEDIMENT �
RSF-X � POND 2
POND OUTLET PIPE
�\ ��` '� ✓ 1 ! I DISCHARGE TO
���� �� / ♦I�� �� �� KINGS SEEK EXISTING STORM
DRAINAGE FEATURE
�` —„ �` i/ CFS 1 TECH CENTER H
SEDIMENT POND WRC-61 � / / _� (TYP.)o
wavg 1
PROPOSED 24" �` � / / I ' _ _ __ -------- % RECB _ --_____- = RECB
.� ,��� �� � RECB
CULVERT \ \ ------------ �w -- ------------------
- F
�� _
II♦ \��� �� 1 SOUTH CREEK PHASE-1A I —
___ FRENCH DRAIN \��
SEDIMENT RESERVOIR m SEDIMENT POND HOLIDAY INN DRIVE I
PERIMETER RIP-RAP �� ` —► / POND w 2A (FUTURE
CHANNEL (TYP.) �-� ` _ =�� WRC-51 SEDIMENT POND 1A m I PHASE-1 B j I L=::::::: PHASE-1C
\\
POND OUTLET PIPE DISCHARGE I OPERATIONAL I (AREA=27.5 AC.) I (AREA=21 AC.)
OSF SEDIMENT TO SOUTH CREEK (FUTURE OPERATIONAL \I I POND M-12 I -___-_-
OVERBURDEN STOCKPILE POND 3 POND M-1 1) I —� �_ I �----------
POND OUTLET PIPE DISCHARGE — __ __ __ _ ______ ______-- ----1- ------------------
POND OUTLET(OSF-3) TO SOUTH CREEK -___ _ RECB ______—__ ____ ______
POND OUTLET PIPE RECB -_-- -
DISCHARGE TO POND-M 1 1 ECB I I CFS LOD DIVERSION BERM
KINGS CREEK (TYP.) j� (TYP.) (TYP.) 1-85
------------ ----_-----I --- _ _ K
KINGS CREEK i I INDUSTRIAL DRIVE
CFS now- I �,
(TYP.)
— -— — PHASE-2A I I I
POND OUTLET PIPE
TEMP SEDIMENT \` (AREA=38.5 AC.) TOP OF
DISCHARGE TO I POND B1 \ \ I CUT CLOPE
KINGS CREEK - PHASE-2B ��\ I I
� - �� (AREA=13.4 AC.) I L
--- � ` TEMP SEDIMENT TEMP SEDIMENT/00 � l
MISC. WASTE I �� X �� POND B2 POND B3 I I
STORAGE ---- 1 `� i I
own
I
TOE OF - v _ --------------- -----
1 POND OUTLET PIPE SLOPE
DISCHARGE TO ---- I TOP OF
KINGS CREEK
KINGS CREEK ---J CUT CLOPE __ I TOE OF
SLOPE
POND-CO2 ,� ^ _ / - - _ _ M
-POND OUTLET PIPE
i POND OUTLET PIPE WATER STORAGE - _.�-DISCHARGE TO
DISCHARGE TO BASIN (WSB-1) EXISTING GROUND
EXISTING GROUND
SEE ENLARGED DRAWING NUMBER
(H371132-5200-222-270-0002) FOR -
N
CONSTRUCTION STORMWATER MANAGEMENT
1' PLAN FOR DUKE'S SUBSTATION PAD
GALILEE CHURCH
I
ROAD OVERALL SITE DRAINAGE PLAN
� �YORK ROAD P
-------------- SCALE: 1"=400'-0"
HATCH ___
-- ___ ALBEMARLETM KINGS MOUNTAIN
DRAFTSPERSON E. MOPENO NR 03 28 24 -- C 0 R P 0 R A T 1 0 N 348 HOLIDAY INN DRIVE
DESIGNER E. MOPENO NR 03 28 24 ___ --- KINGS MOUNTAIN, NC 28286
CHECKER S. ALUGUVELU This drawing is the confidential property of Albemarle Corporation and is issued with the express understanding and agreement that it
DESIGN COORD. T. KAISER --- is not to be copied or reproduced,or used in any way detrimental to the interest of Albemarle Corporation and is to be returned on request.
ISSUED F 0 R PERMITTING RESP. ENG. S ALUGUVE2u --- ___ MINING AND CONCENTRATOR FACILITY
LEAD DISC. ENG. S. ALUG_V-2u MINE SELECT PHASE
ENG. MANAGER PHASE 2 CONSTRUCTION
NOT FOR CONSTRUCTION PROD. MANAGER K. YOUNG C ISSUED FOR PERMITTING
ELM SRA TPK 07/11/24 STORMWATER PLAN
ROLE NAME SIGNATURE DATE B ISSUED FOR PERMITTING ELM SRA TPK 04/03/24 JOB NO. DRAFTER: DRAWING NO. SHT. 1 of 1 REVISION R
SCALE DATE
INTERNAL&CLIENT REVIEW KM22040 E. MORENO
A ELM SRA TPK 03/29/24 KM61 —Cl-GA-00106 C
HATCH DRAWING NUMBER: H371132-4000-222-270-0004
REV# r DESCRIPTION CADD CHK'D APPR'D DATE AS NOTED 03/28/24

ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Exhibit C:
Duke Substation Pad Construction
Stormwater Management Plan
H371132-4000-220-230-0001, Rev. C
©Hatch 2024 All rights reserved,including all rights relating to the use of this document or its contents.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
/
LEGEND:
FEMA 100-YR 60' PROPOSED TOE OF FILL SLOPE A
I FLOODPLAIN BOUNDARY WETLAND
WETLAND PROPOSED TOP OF CUT SLOPE
50' BUFFER
/ 50' BUFFER
FLOW PATH
/ WETLAND BOUNDARY — — — DEVELOPMENT PHASE BOUNDAR
/ RIP-RAP DETENTION POND OUTLET i B
/ PIPE DISCHARGE LOCATION LIMITS OF DISTURBANCE
(LOD)
/ ROCK CONSTRUCTION
ENTRANCE & EXIT
/ I (PRACTICE 6.06)
1 /
EROSION CONTROL
0 0 i RECB BLANKET (PRACTICE 6.17) C
LO
Lu r!.
SUPER SILT FENCE/COMPOST
" OUTLET PIPE FILTER SOCK (CFS)
two WEPPM 24
(PRACTICE 6.66.6.62)
18" OUTLET PIPE TEMPORARY SEDIMENT CDDROP CONNECTION MANHOLE POND-3 SEDIMENT BASIN WITH SKIMMER
-���•'�` (SEE DRAWING KM60-CI-PN-001 00 (PRACTICE 6.61)
FOR DROP CONNECTION DETAIL) _- '^---___--- _ --------- RIPRAP LINED CHANNEL D
(PRACTICE 6.21)
18" OUTLET PIPE----- 810,
__________ OUTLET PROTECTION LEVEL
�� �` SPREADER (PRACTICE 6.4)
TOP OF POND . RECB
EL. 830.00'-I RECB �20 ` M DUKE SUBSTATION 2 ��I\
------ DIVERSION BERM
DUKE SUBSTATION / ����\ �� SEDIMENT POND — 1 80'
SEDIMENT POND - 2 PIT PUMP AND PIPING E
f - , g0` \ \ /♦ ti6 i w SKIMMER �� POND LINER REQUIRED ON
w/ SKIMMER 1 '1 \ // r 830 ��
1 , , \ /� RECB �\ FILL SLOPE TO PREVENT
1 RECB / '� \ \ �,; 830' 830, \� TEMPORARY CONSTRUCTION
_ \� SLOPE DETERIORATION. FENCE (TCF)
�6' RISER 1 �• o ' �5gs�� -� �\`\ q, 6 1\ CULVERT DRAIN
1
RECB \\ \\ j INLET
RECB STRUCTURE BOTTOM OF POND i 60' FRENCH DRAIN
EL. 824.00' 1 F
840 RECB RECB STORM SEWER/OUTLET
RECB
STRUCTURE
850' 850'
PAD CONSTRUCTION
BY OTHERS G
RECB ' �CID
0
M o
H
RECB
rA
LAYDOWN AREA oho o FG EL. 850.00
RECB
RECB �0 J
PROPOSED 24" HDPE `840'
DRIVEWAY CULVERT
K
850' 850'
850'
0
rn
PROPOSED 24" HDPE _4% L
DRIVEWAY CULVERT
PROPOSED GRAVEL ROAD
PROPERTY LINE
860'
I
GALfLEE CHURCH ROgp I ROCK CONSTRUCTION
ENTRI M
1 PROPOSED 24" HDPE
DRIVEWAY CULVERT
OUTLET PROTECTION -\� �' �\
idi
LEVEL SPREADER j
N
PLAN - DUKE SUBSTATION PAD
SCALE: 1 "= 60'
P
HL\TCH ___ ___
__ ALBEMARLETM KINGS MOUNTAIN
DRAFTSPERSON E. MORENO NR 06 18 24 -- C 0 R P 0 R A T 1 0 N 348 HOLIDAY INN DRIVE
DESIGNER E. MORENO NR 06 1 8 24 -- -- KINGS MOUNTAIN, NC 28286 ^
CHECKER S. ALUGUVELD This drawing is the confidential property of Albemarle Corporation and is issued with the express understanding and agreement that it (�
DESIGN COORD. T. KAISER is not to be copied or reproduced,or used in any way detrimental to the interest of Albemarle Corporation and is to be returned on request.
ISSUED F 0 R PERMITTING RESP. ENG. S. ALUGuvELu =-_ ___ MINING AND CONCENTRATOR FACILITY
LEAD DISC. ENG. S. ALUGUVELu MINE SELECT PHASE
ENG. MANAGER --- DUKE SUBSTATION ENLARGED
NOT FOR CONSTRUCTION PROJ. MANAGERK. YOUNG =__
CONSTRUCTION STORM WATER PLAN
B ELM SRA TPK 07/11/24
ROLE NAME SIGNATURE DATE ISSUED FOR PERMITTING JOB NO. DRAFTER: DRAWING NO. SHT. 1 of 1 REVISION R
KM22040 E. MORENO
INTERNAL REVIEW
HATCH DRAWING NUMBER:
A ELM SRA TPK 07/10/24 SCALE- DATE KM60-CI-GA-00101 B REV# DESCRIPTION CADD CHK'D APPR'D DATE AS NOTED 06/18/24

ALBEMARLE' HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Exhibit D:
Erosion and Sediment Control Details
H371132-4000-220-230-0001, Rev. C
©Hatch 2024 All rights reserved,including all rights relating to the use of this document or its contents.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
A
3
FT. MOUNTABLE o
BERM (6 IN. MIN.)* L-2 COMPOST FILTER SOCK 2 IN. x 2 IN. WOODEN STAKES The maximum slope length above a compost filter sock should not exceed those shown in Figure 4.2. NOTE:
50' MIN. PLACED 10 FT ON CENTER Slope length is not addressed by use of multiple rows of compost socks. The anticipated functional life of a biodegradable filter
12 IN. DIA. SOCK BLOWN/PLACED sock should be 6 months; for photodegradable socks it is 1 year. Some other types may last longer.
EXISTING ROADWA Y FILTER MEDIA Projects with disturbances anticipated to last longer then the functional life of a sock should plan to replace
18 IN. DIA. SOCK the socks periodically or use another type of BMP.
UNDISTURBED AREA
DISTURBED AREA Upon stabilization of the tributary area, the filter sock may be left in place and vegetated or removed. In
GEOTEXTILE O EARTH FILL 24 IN. DIA. SOCK \�� the latter case, the mesh is typically cut open and the mulch spread as a soil supplement. In either case,
VAiiA�AA�2zVA VA v \ ��v�, the stakes should be removed.
EXISTING MIN 8" AASHTO #1 PIPE AS NECESSARY PLAN VIEW
GROUND Filter socks using other fillers may be approved on a case—by—case basis if sufficient supporting
(2)-2 IN. X 2 IN. X 48 IN. HARDWOOD STAKES, in formation(including manufacturers specs and independent test data) is provided. However, they might not
12 IN. WRAPPED TOGETHER WITH 16 GA. WIRE, 10 FT. O.C. \ SECTION qualify as ABACts. Whereever compost socks are used, Table 4.1 should be placed on a detail sheet.
PROFILE ABOVE SOCK 2 IN. X 2 IN. X 36 IN. HARDWOOD STAKE, 10 FT O.C. TABLE 4.1
STARTING 5 FT. FROM ANGLED STAKES \ i /
\ BLOWN/PLACED FILTER MEDIA ® �o� EI Compost Stock Fabric Minimum Specifications
REMOVE BRUSH AND WOODY DEBRIS DISTURBED AREA i
o ? �o� '— �o �o�� Multi-Filament Heavy Duty C
3 mil HDPE 5 mil HDPE 5 mil HDPE Multi-Filament
Type Polypropylene Polypropylene
Material T e
o ro ene
MFPP
MFPP
XISTING
O ao CONTOURS Material
Photo— Photo— Bio— Photo— Photo—
Characteristics degradable degradable degradable degradable degradable
R
N (3 UNDISTURBED GROUND
STAKING DETAIL 1 " 1 „ 1 „ 12„ 1 „
FILTER MSOCK UNDISTURBED AREA WOODEN STAKES Diameters POST IN. x 2 IN. Sock 188" 188 188 18 188
24" 24" 24" 24"
L4 DESIGN NOTES: PLACED 10 FT ON 32" 32" 32" 32"
PLAN VIEW — 1. COMPOST SOCK SEDIMENT TRAP SHALL BE SIZED TO PROVIDE 2000 CUBIC FEET OF STORAGE CAPACITY PLAN VIEW CENTER
FOR EACH ACRE TRIBUTARY TO THE TRAP. Mesh Opening 3/8" 3/8" 3/8" 3/8" 3/8"
2. MINIMUM BASE WIDTH IS EQUAL TO THE HEIGHT.
3. SEDIMENT ACCUMULATION SHALL NOT EXCEED 1/3 THE TOTAL HEIGHT OF THE TRAP. Tensile
4. SOCKS SHALL BE OF LARGER DIAMETER AT THE BASE OF THE TRAP AND DECREASE IN DIAMETER FOR NOES: Strength 26 psi 26 psi 44 psi 202 psi
SUCCESSIVE LAYERS AS SHOWN ON THE PLAN VIEW.
5. ENDS OF THE TRAP SHALL BE A MINIMUM OF 1 FOOT HIGHER IN ELEVATION THAN THE MID—SECTION, SOCK FABRIC AND COMPOST SHALL MEET STANDARDS OF NCDEQ STORMWATER BMP MANUAL Ultraviolet
* MOUNTABLE BERM USED TO PROVIDE PROPER COVER FOR PIPE WHICH SHALL BE LOCATED AT THE POINT OF DISCHARGE.
COMPOST FILTER SOCK SHALL BE PLACED AT EXISTING LEVEL GRADE. BOTH ENDS OF THE Stability% 23% at 23% at 100% at 100% at
NOTES: NOTES: BARRIER SHALL BE EXTENDED AT LEAST 8 FEET UP SLOPE AT 45 DEGREES TO THE MAIN Origianl Strength 1000 hr. 1000 hr. 1000 hr. 1000 hr. E
BARRIER ALIGNMENT. MAXIMUM SLOPE LENGTH ABOVE ANY BARRIER SHALL NOT EXCEED THAT (ASTM G-155)
REMOVE TOPSOIL PRIOR TO INSTALLATION OF ROCK CONSTRUCTION ENTRANCE. EXTEND ROCK SOCK FABRIC AND COMPOST SHALL MEET STANDARDS OF NCDEQ STORMWATER BMP MANUAL SPECIFIED FOR THE SIZE OF THE SOCK AND THE SLOPE OF ITS TRIBUTARY AREA.
OVER FULL WIDTH OF ENTRANCE. Minimum
COMPOST SOCK SEDIMENT TRAPS SHALL NOT EXCEED THREE SOCKS IN HEIGHT AND SHALL BE STACKED IN TRAFFIC SHALL NOT BE PERMITTED TO CROSS COMPOST FILTER SOCKS. Functional 6 months 9 months 6 months 1 year 2 years
PYRAMIDAL FORM AS SHOWN ABOVE. MINIMUM TRAP HEIGHT IS ONE 24" DIAMETER SOCK. ADDITIONAL STORAGE ACCUMULATED SEDIMENT SHALL BE REMOVED WHEN IT REACHES 1/2 THE ABOVE GROUND
RUNOFF SHALL BE DIVERTED FROM ROADWAY TO A SUITABLE SEDIMENT REMOVAL BMP PRIOR MAY BE PROVIDED BY MEANS OF AN EXCAVATED SUMP 12" DEEP EXTENDING 1 TO 3 FEET UPSLOPE OF THE HEIGHT OF THE BARRIER AND DISPOSED IN THE MANNER DESCRIBED ELSEWHERE IN THE PLAN. Longevity
TO ENTERING ROCK CONSTRUCTION ENTRANCE. SOCKS ALONG THE LOWER SIDE OF THE TRAP. COMPOST FILTER SOCKS SHALL BE INSPECTED WEEKLY AND AFTER EACH RUNOFF EVENT. Two-ply systems
DAMAGED SOCKS SHALL BE REPAIRED ACCORDING TO MANUFACTURER'S SPECIFICATIONS OR
MOUNTABLE BERM SHALL BE INSTALLED WHEREVER OPTIONAL CULVERT PIPE IS USED AND COMPOST SOCK SEDIMENT TRAPS SHALL PROVIDE 2,000 CUBIC FEET STORAGE CAPACITY WITH 12" FREEBOARD REPLACED WITHIN 24 HOURS OF INSPECTION. HDPE biaxial net
PROPER PIPE COVER AS SPECIFIED BY MANUFACTURER IS NOT OTHERWISE PROVIDED. PIPE FOR EACH TRIBUTARY DRAINAGE ACRE. (SEE MANUFACTURER FOR ANTICIPATED SETTLEMENT.) Inner Containment Netting Continuously wound
SHALL BE SIZED APPROPRIATELY FOR SIZE OF DITCH BEING CROSSED. BIODEGRADABLE COMPOST FILTER SOCKS SHALL BE REPLACED AFTER 6 MONTHS; Fuson-welded junctures
THE MAXIMUM TRIBUTARY DRAINAGE AREA IS 5.0 ACRES. SINCE COMPOST SOCKS ARE "FLOW—THROUGH," NO PHOTODEGRADABLE SOCKS AFTER 1 YEAR. POLYPROPYLENE SOCKS SHALL BE REPLACED SPILLWAY IS REQUIRED. ACCORDING TO MANUFACTURERS RECOMMENDATIONS. 3/4"x3/4" Max.aperture size F
MAINTENANCE: ROCK CONSTRUCTION ENTRANCE THICKNESS SHALL BE CONSTANTLY MAINTAINED Composite Polypropylene Fabric
TO THE SPECIFIED DIMENSIONS BY ADDING ROCK. A STOCKPILE SHALL BE MAINTAINED ON SITE COMPOST SOCK SEDIMENT TRAPS SHALL BE INSPECTED WEEKLY AND AFTER EACH RUNOFF EVENT. SEDIMENT UPON STABILIZATION OF THE AREA TRIBUTARY TO THE SOCK, STAKES SHALL BE REMOVED. THE (Woven layer and non-woven fleece
FOR THIS PURPOSE. ALL SEDIMENT DEPOSITED ON PAVED ROADWAYS SHALL BE REMOVED AND SHALL BE REMOVED WHEN IT REACHES 1/3 THE HEIGHT OF THE SOCKS. SOCK MAY BE LEFT IN PLACE AND VEGETATED OR REMOVED. IN THE LATTER CASE, THE MESH Outer Filtration Mesh mechanical) fused via needle punch)
RETURNED TO THE CONSTRUCTION SITE IMMEDIATELY. IF EXCESSIVE AMOUNTS OF SEDIMENT SHALL BE CUT OPEN AND THE MULCH SPREAD AS A SOIL SUPPLEMENT. y p )
ARE BEING DEPOSITED ON ROADWAY, EXTEND LENGTH OF ROCK CONSTRUCTION ENTRANCE BY PHOTODEGRADABLE AND BIODEGRADABLE SOCKS SHALL NOT BE USED FOR MORE THAN 1 YEAR. 3/16"Max.aperture size
50 FOOT INCREMENTS UNTIL CONDITION IS ALLEVIATED OR INSTALL WASH RACK. WASHING THE Sock fabrics composed of burlap may be used on projects lasting 6 months or less.
ROADWAY OR
IN SWEEPING THE DEPOSITS INTO ROADWAY DITCHES, SEWERS, CULVERTS, OR TEMPORARY COMPOST SOCK SEDIMENT TRAP p p g g p
OTHER DRAINAGE COURSES IS NOT ACCEPTABLE. COMPOST FILTER SOCK Compost should be a well decomposed, weed free organic matter derived from agriculture, food, stump
(PRACTICE 666A) grindings, and yard or wood/bark organic matter sources. The compost should be aerobically composted. The
(PRACTICE 6.60) . compost should possess no objectionable odors and shall be reasonable free
TEMPORARY ROCK CONSTRUCTION ENTRANCE/EXIT NOT TO SCALE NOT TO SCALE NOTE: G
(PRACTICE 6.6) INSTALLATION AND SPECIFICATIONS IN ACCORDANCE WITH NORTH CAROLINA
EROSION AND SEDIMENT CONTROL PLANNING AND DESIGN MANUAL.
NOT TO SCALE
INLET GRATE
Compost Sack - Co st Sack m� 1 IN. REBAR FOR
31N. 31N, .�,� XPANSION RESTRAINT
AREfITQBE L,. PROTECTED
BAG REMOVAL FROM
cat-�Vf PROTECTED
_I[j6+L+� I (1/4 IN. NYLON ROPE)
STAKE
--. PK�PECTEi] INLET
12 IN MIN. 'j 12 IN N IN. r 2 IN X 26IN. X 3/4 IN.
+ FinxZin —zInK24n 're>,
Qp�i�_ TAPLES
STAKES STAKES 2 IN. X 2 IN. X 36 IN. J
(t3/8 IN) WOOD STAKES * SECTION SECTION INSTALLATION DETAIL
JOINING FENCE SECTIONS .cr
SUPPORT STAKE
OMPACTEDh $
�ABRIC FENCE III BACKFILL FILL
2:1 MAX.
BALE BIND IN � ...J \ T BERM K
�� III � SLOPE
OMPACED FILL _ •
BACKFILL SLOPE
UNDISTURBED
UNDISTURBED ��\ ISOMETRIC VIEW FLOW
GROUND - i TRENCH INTO
L �T�� GROUND * 2 STAKES PER BALE 6ROUND EARTHEN BERM TO BE STABILIZED WI
4 IN.IV11N_ TEMPORARY OR PERMANENT VEGETATION 2:1 MAX %3:1
TOE ANCHOR TRENCHWOCD Iw1UIGNUR Ca7MIPDT FLOW (TYP.)
6 IN. * STAKES SPACED AT 8 FT. MAX. TO 1/7 HEIGHTOP LOG 6 IN.
USE 2 IN X 2 IN (t3/8 IN.) WOOD OR V STORM MIN.
EQUIVALENT STEEL (U OR T) STAKES UNTRIENCHE'D INSTALLATION ENTRENCHED INSTALLATION* INLET HEIGHT
SECTION VIEW *TH S APPLICATION MAY NOT'8e USED
WITH C€}tAFC6T SACKS SMALLER TkAN 13 IN. L
SECTION VIEW NOTES: SECTION VIEW PLAN VIEW
ISOMETRIC VI'E11V'
STRAW BALE BARRIERS SHALL NOT BE USED FOR PROJECTS EXTENDING MORE THAN 3 MONTHS. NOTES:
NOTES:
STRAW BALE BARRIERS SHALL BE PLACED AT EXISTING LEVEL GRADE WITH ENDS TIGHTLY ABUTTING MAXIMUM DRAINAGE AREA = 1/2 ACRE.
FABRIC SHALL HAVE THE MINIMUM PROPERTIES AS SHOWN IN TABLE 4.3 OF THE PA DEP EROSION THE ADJACENT BALES. FIRST STAKE OF EACH BALE SHALL BE ANGLED TOWARD ADJACENT BALE TO
CONTROL MANUAL. DRAW BALES TOGETHER. STAKES SHALL BE DRIVEN FLUSH WITH THE TOP OF THE BALE. BOTH ENDS INLET PROTECTION SHALL NOT BE REQUIRED FOR INLET TRIBUTARY TO SEDIMENT BASIN OR
OF THE BARRIER SHALL BE EXTENDED AT LEAST 8 FEET UP SLOPE AT 45 DEGREES TO THE MAIN 11Auhdi or Compost TRAP. BERMS SHALL BE REQUIRED FOR ALL INSTALLATIONS.
FABRIC WIDTH SHALL BE 30 IN. MINIMUM. STAKES SHALL BE HARDWOOD OR EQUIVALENT STEEL (U BARRIER ALIGNMENT. for Untrenched Sacks
OR T) STAKES. ROLLED EARTHEN BERM IN ROADWAY SHALL BE MAINTAINED UNTIL ROADWAY IS STONED. ROAD
COMPACTED BACKFILL SHALL EXTEND APPROXIMATELY 4 IN. ABOVE GROUND LEVEL. AREATORE SUBBASE BERM ON ROADWAY SHALL BE MAINTAINED UNTIL ROADWAY IS PAVED. EARTHEN M
SILT FENCE SHALL BE PLACED AT LEVEL EXISTING GRADE. BOTH ENDS OF THE FENCE SHALL BE PROTECTED BERM IN CHANNEL SHALL BE MAINTAINED UNTIL PERMANENT STABILIZATION IS COMPLETED OR
EXTENDED AT LEAST 8 FEET UP SLOPE AT 45 DEGREES TO THE MAIN FENCE ALIGNMENT. SEDIMENT SHALL BE REMOVED WHEN ACCUMULATIONS REACH 1/3 THE ABOVE GROUND HEIGHT OF REMAIN PERMANENTLY.
THE BARRIER. DAMAGED OR DETERIORATED BALES SHALL BE REPLACED IMMEDIATELY UPON Shrrt FIcjW
SEDIMENT SHALL BE REMOVED WHEN ACCUMULATIONS REACH HALF THE ABOVE GROUND HEIGHT OF INSPECTION. Compost sack AT A MINIMUM, THE FABRIC SHALL HAVE A MINIMUM GRAB TENSILE STRENGTH OF 120 LBS., A
THE FENCE. MINIMUM BURST STRENGTH OF 200 PSI, AND A MINIMUM TRAPEZOIDAL TEAR STRENGTH OF 50
ANY SECTION OF STRAW BALE BARRIER WHICH HAS BEEN UNDERMINED OR TOPPED SHALL BE LES. FILTER BAGS SHALL BE CAPABLE OF TRAPPING ALL PARTICLES NOT PASSING A NO. 40
ANY SECTION OF SILT FENCE WHICH HAS BEEN UNDERMINED OR TOPPED SHALL BE IMMEDIATELY IMMEDIATELY REPLACED WITH A ROCK FILTER OUTLET (STANDARD CONSTRUCTION DETAIL #4-6). SIEVE.
REPLACED WITH A ROCK FILTER OUTLET. Work Area
BALES SHALL BE REMOVED WHEN THE TRIBUTARY AREA HAS BEEN PERMANENTLY STABILIZED. INLET FILTER BAGS SHALL BE INSPECTED ON A WEEKLY BASIS AND AFTER EACH RUNOFF
FENCE SHALL BE REMOVED AND PROPERLY DISPOSED OF WHEN TRIBUTARY AREA IS PERMANENTLY EVENT. BAGS SHALL BE EMPTIED AND RINSED OR REPLACED WHEN HALF FULL OR WHEN FLOW
STABILIZED. CAPACITY HAS BEEN REDUCED SO AS TO CAUSE FLOODING OR BYPASSING OF THE INLET.
OR CLOGGE BAGS SHALL BEMAINTAINED ON
SILT FENCE NOTE: FOR EPLACEMENT OD BAGS. ALL NEEDEDE T REPAIRS SHALL BE INATEDA SUPPLY SHALLEIMMEDIATELY AFTERTE
STANDARD CONSTRUCTION DETAIL #4-13 N
PRACTICE 6.62 THE INSPECTION. DISPOSE ACCUMULATED SEDIMENT AS WELL AS ALL USED BAGS ACCORDING
( ) STRAW BALE BARRIER TO THE PLAN NOTES.
NOT TO SCALE PLAN INSTALLATION AND
NOT TO SCALE SPECIFICATIONS IN ACCORDANCE DO NOT USE ON MAJOR PAVED ROADWAYS WHERE PONDING MAY CAUSE TRAFFIC HAZARDS.
FILTER SOCK INSTALLATION WITH NORTH CAROLINA EROSION
AND SEDIMENT CONTROL FILTER BAG INLET PROTECTION
PLANNING AND DESIGN MANUAL.
NOT TO SCALE NOT TO SCALE
P
HL\TCH ___- J\ALBEMA LET. KINGS MOUNTAIN
DRAFTSPERSON D. EAMECH NR 083023 -- C 0 R P 0 R A T 1 0 N 348 HOLIDAY INN DRIVE
DESIGNER D. EAMECH NR 08-30-23 --- --- KINGS MOUNTAIN, NC 28286 CHECKER S. AFUGUVFLU This drawing is the confidential property of Albemarle Corporation and is issued with the express understanding and agreement that it Q
DESIGN COORD. T. KAISER
__ --- is not to be copied or reproduced,or used in any way detrimental to the interest of Albemarle Corporation and is to be returned on request.
RESP. ENG, S. AFUGUVFLU --- MINING AND CONCENTRATOR FACILITY
ISSUED F 0 R PERMITTING LEAD DISC' ENG' S AEUGUVELU E ISSUED FOR PERMITTING JT SA CC 04-03-24
MINE SELECT PHASE
ENG. MANAGER D ISSUED FOR SELECT JT SA cc 12-15-23 EROSION AND SEDIMENT CONTROL
PROJ. MANAGER K. YOUNG FOR CLIENT REVIEW
NOT FOR CONSTRUCTION C DL SA GC 11-30-23 TYPICAL DETAILS
_RGE NAME SIGNATURE DATE B DL SA CC 10-06-23 FOR INTERNAL REVIEW JOB NO. DRAFTER: DRAWING NO. SHT. 1 of 1 REVISION R
L
F KM22040 D. LAMECH
ORINTERNAL REVIEW
A DL SA CC 8-30-23 SCALE: DATE KM61 -CI-DT-001 00 E
HATCH DRAWING NUMBER: H371132-4100-222-292-0001
REV# DESCRIPTION CADD CHK'D APPR'D DATE NTS 08-30-23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
WELL VEGETATED, GRASSY AREA
DISCHARGE HOSE L = The distance such ,hat ooin:s
MAXIMUM DEPTH OF
CONTAMINATED WATER IS50%OF LAMPS BLANKET EDGES and2fP. O P.C�Ilcil P.It3v�11 (Ill A
STACKED FILTER RING-"HEIGHT INSTALL BEGINNING OF ROLL
2'x 2"x 36'WOODEN UMP STAPLED AND IN 6 IN. x 6 IN. ANCHOR
STACKED 18"DIAMETER
O.G. �FILTREXX@SOXX- NTAKE HOSE OVERLAPPED
STAKES PLACED 5' TRENCH, STAPLE, BACKFILL
(ALSO AVAILABLE INS^, FILTER BAG (4 IN. MIN.) AND COMPACT SOIL
A B
12"AND 24"DIAMETERS)
} STARTING AT TOP
SLOPE, ROLL BLANKETS IN ��.. -- 7-.
H DIRECTION OF WATER FLOW
1•
SECTION drs . _ _ . . .
11 i . . W W .
EAVY DUTY LIFTING STRAPS
�� \� ��i
NOTES: (RECOMMENDED) \ \i 1 V min
1. INSTALL ON FLAT GRADEFOR PLAN VIEW
OPTIMUM PERFORMANCE
2.FILTER SOXX-MAY BE DIRECT PUMP CONTAMINATED ISCHARGE HOSE Tin /
SEEDED AT THE TIME OF WATER INTO CONCRETE LAMPS PREPARE SEED BED _______ __ ________ __ ____ _ sJ
INSTALLATION =- — WASHOUT (INCLUDING APPLICATION OF LIME,
FERTILIZER AND SEED) PRIOR TO
BLANKET INSTALLATION >r '
—_��_ r FILTER BAG rr ,tvi
t C
18-DIAMETE R
FILTREXx&SOxx"' WELL VEGETATED, GRASSY AREA R
- (ALSO AVAILABLE IN \
8",12"AND24"
IIIII DIAMETERS) PUM INTAKE HOSE Filter Cloth
ELEVATION VIEW
NOTES: Plain View
THE BLANKET SHOULD OVERLAP BLANKET ENDS 6 IN. MIN. REFER TO MANUF. RECOMMENDED
LOW VOLUME FILTER BAGS SHALL BE MADE FROM NON-WOVEN GEOTEXTILE MATERIAL SEWN WITH HIGH NOT BE STRETCHED; WITH THE UPSLOPE BLANKED STAPLING PATTERN FOR
STRENGTH, DOUBLE STITCHED "J" TYPE SEAMS. THEY SHALL BE CAPABLE OF TRAPPING PARTICLES LARGER IT MUST MAINTAIN OVERLYING THE DOWNSLOPE BLANKET STEEPNESS AND LENGTH OF 12'of NCDOT#5 or#57
THAN 150 MICRONS. HIGH VOLUME FILTER BAGS SHALL BE MADE FROM WOVEN GEOTEXTILES THAT MEET THE GOOD SOIL CONTACT (SHINGLE STYLE). STAPLE SECURELY. SLOPE BEING BLANKETED washed stone 15, D
FOLLOWING STANDARDS:
{' PROPERTY TEST METHOD MINIMUM STANDARD y
AVG. WIDE WIDTH STRENGTH ASTM D-4884 60 LB/IN NOTES:
Class B Riprap
GRAB TENSILE ASTM D-4632 205 LB
SEED AND SOIL AMENDMENTS SHALL BE APPLIED ACCORDING TO THE RATES IN THE PLAN DRAWINGS PRIOR TO s 2' max
PUNCTURE ASTM D-4833 110 LB INSTALLING THE BLANKET. t cente
MULLEN BURST ASTM D-3786 350 PSI
`L PROVIDE ANCHOR TRENCH AT TOE OF SLOPE IN SIMILAR FASHION AS AT TOP OF SLOPE.
UV RESISTANCE ASTM D-4355 70% Filter Cloth � � / ,•
2'X 2*X 3W WOODEN AOS % RETAINED ASTM D-4751 80 SIEVE SLOPE SURFACE SHALL BE FREE OF ROCKS, CLODS, STICKS, AND GRASS.
PLAN , STAKES PLACED5'O _iG. A SUITABLE MEANS OF ACCESSING THE BAG WITH MACHINERY REQUIRED FOR DISPOSAL PURPOSES SHALL BE r -1 ' E
PROVIDED. FILTER BAGS SHALL BE REPLACED WHEN THEY BECOME 1/2 FULL OF SEDIMENT. SPARE BAGS SHALL BLANKET SHALL HAVE GOOD CONTINUOUS CONTACT WITH UNDERLYING SOIL THROUGHOUT ENTIRE LENGTH. LAY rr
BE KEPT AVAILABLE FOR REPLACEMENT OF THOSE THAT HAVE FAILED OR ARE FILLED. BAGS SHALL BE PLACED BLANKET LOOSELY AND STAKE OR STAPLE TO MAINTAIN DIRECT CONTACT WITH SOIL. DO NOT STRETCH
ON STRAPS TO FACILITATE REMOVAL UNLESS BAGS COME WITH LIFTING STRAPS ALREADY ATTACHED. BLANKET. -0 6
FILTREXX4 CONCRETE WASHOUT BAGS SHALL BE LOCATED IN WELL-VEGETATED (GRASSY) AREA, AND DISCHARGE ONTO STABLE, EROSION THE BLANKET SHALL BE STAPLED IN ACCORDANCE WITH THE MANUFACTURER'S RECOMMENDATIONS. Cf osS-5CC11on View
RESISTANT AREAS. WHERE THIS IS NOT POSSIBLE, A GEOTEXTILE UNDERLAYMENT AND FLOW PATH SHALL BE
NTS PROVIDED. BAGS MAY BE PLACED ON FILTER STONE TO INCREASE DISCHARGE CAPACITY. BAGS SHALL NOT BE BLANKETED AREAS SHALL BE INSPECTED WEEKLY AND AFTER EACH RUNOFF EVENT UNTIL PERENNIAL
PLACED ON SLOPES GREATER THAN 5%. FOR SLOPES EXCEEDING 5%, CLEAN ROCK OR OTHER NON-ERODIBLE VEGETATION IS ESTABLISHED A MINIMUM UNIFORM 70% COVERAGE THROUGHOUT THE BLANKETED AREA.
AND NON-POLLUTING MATERIAL MAY BE PLACED UNDER THE BAG TO REDUCE SLOPE STEEPNESS. DAMAGED OR DISPLACED BLANKETS
ETS SHALL BE RESTORED OR REPLACED WITHIN 4 CALENDAR DAYS.
ROCK CHECK DAM
NO DOWNSLOPE SEDIMENT BARRIER IS REQUIRED FOR MOST INSTALLATIONS. COMPOST BERM OR COMPOST ROLLED EROSION CONTROL BLANKET INSTALLATION (PRACTICE 6.83) F
FILTER SOCK SHALL BE INSTALLED BELOW BAGS LOCATED IN HQ OR EV WATERSHEDS, WITHIN 50 FEET OF ANY
RECEIVING SURFACE WATER OR WHERE GRASSY AREA IS NOT AVAILABLE. (PRACTICE 6.17) NOT TO SCALE
THE PUMP DISCHARGE HOSE SHALL BE INSERTED INTO THE BAGS IN THE MANNER SPECIFIED BY THE NOT TO SCALE
MANUFACTURER AND SECURELY CLAMPED. A PIECE OF PVC PIPE IS RECOMMENDED FOR THIS PURPOSE.
THE PUMPING RATE SHALL BE NO GREATER THAN 750 GPM OR 1/2 THE MAXIMUM SPECIFIED BY THE
MANUFACTURER, WHICHEVER IS LESS. PUMP INTAKES SHALL BE FLOATING AND SCREENED.
FILTER BAGS SHALL BE INSPECTED DAILY. IF ANY PROBLEM IS DETECTED, PUMPING SHALL CEASE IMMEDIATELY Trapezoidal Riprap Channel
AND NOT RESUME UNTIL THE PROBLEM IS CORRECTED. L)E" G
SI�I'l C0� rnrldlh ' ` I'
40
=1
TOE of yp. (MIN.) PUMPED WATER FILTER BAG Ly,, Design depth
SLOPE NOT TO SCALE
STANDARD SILT FENCE s I I ;� - RISER Sl;�UCt URL
( °(STD. CONST. DETAIL #4-7),
STRAW BALE BARRIER STEEL POSTS(QUANTITY VAR.) SKIMMER(SIZE VAR.)
(STD. CONST. DETAIL 4-13) Filter layer,, gravel
OR COMPOST FILTER SOCK fak}n k , H
EMBANKMENT
(STD. CONST. DETAIL #4-15) STONE ENERGY
40 ZSOIL INSTALL BARRIER WATER ENTRY UNIT PES STANDARD
DRAIN PIPE
STOCKPILE DOWNSLOPE OF RIP-RAP LINED CHANNEL (PRACTICACTICESNOARQ6.321 D1551PATOR
STOCKPILE OR WITH TRASH SCREEN . . OR-\
FOLLOW CONTOUR (PRACTICE 621 AND 631) GEOTEXTILE LINING
NOT TO SCALE
AROUND PILE IF ON
LEVEL GRADE ------
Pipe Outlet to Flat Area- R J
0 0 0 0 0 0 0 o No Well-defined Channel
00000000o TEMPORARYOR ,
0 0 0F7 71 El F1__ o o a PERMANENT DITCH
BORE
-- -4 .� EMERGENCY SPI_LlVAY
00 3dO A- _ A
do _ COIR FIBER BAFFLES
ORIFICE OPENING INSIDE THE r � VIEW
1 PRACTICE STANDARD 6.65 T NE PAD
NOTES: PLAN YIE�Y (below skimmer)HORIZONTAL TUBE WITH A WOOD STAKEK
Plan OR METAL POST
1. COVER SOIL STOCKPILE WITH MULCH OR CONSTANT HYDRAULIC HEAD
EROSION CONTROL FABRIC. TOP OF EMBANKMENT
2. IF STOCKPILE IS TO BE IN PLACE FOR r awl
AN EXCESS OF 20 DAYS, TEMPORARY a �'ar
,i RISER STRUCTURE
SEEDING MUST BE INSTALLED. 1'MIN-
►F Iter EMERGENCY SPILLWAY
Section AA Notes TRASH RACK _ a
3. AFTER COMPLETE UTILIZATION, RETURN bla 1k@: FREEBOARD- (A� I��►AIII✓��►A�
1.'Mlhl, I�IIiI�Rq�RR�RR����IIR�
1. La is the length of the nprap tt,PT �. � � �
STOCKPILE AREA TO NATURAL PRECONSTRUCTION apron. SKIMMER —!► a q� ��lfli kp�lfll IV -kN�Rk�NA-,{fN�11 '�s�oA
I�ua�Ill� u�l I�-uiI�Illllu
Pipe Outlet to nell•deiined �,* �`J11f 11 t
STATE, INCLUDING ALL NECESSARY GRADING SCHEDULE 40 PVC PIPE Channel 2 d=1.5 times the maximum �•� R!{�kp�ll�flt�Nlf�1"1J��1f.��ff��f.�Jrff�Np�Ulr��
AND REVEGETATION. stone diameter but not less(BARREL OR ARM)
IIil�uu�ullrullIll��uuuu uuull �Wu�uu�ll�=uu=
than 6". I i a H BARREL
4. WHERE POSSIBLE LOCATE STOCKPILE AREAS 3. In a well-defined channel ex- r r
ON UPSLOPE SIDE OF EXCAVATION, AWAY FROM tend the apron up the channel PIPE
NEARBY STREAMS, DRAINAGE DITCHES, OR banks to an elevation of 6'
WATER COURSES. - -
A A above the maximum tailwater
depth or to the top of the bank,
' whichever is less. CLASS BSTONE PAD
5. STOCKPILE HEIGHT MUST NOT EXCEED 35 FEET. -- }4'X4'X V MIN.) CUT-OFF ANTI-SEEP
4. A filter blanket or filter fabric ANTIFLOTATION 81_0_K SECTIONAL VlEV11 TRENCH COLLAR STABILIZED M
should be installed betvreen
STORAGE OF STOCKPILE SOIL Plan the riprap and soil foundation T pEEp OUTLET
NOT TO SCALE FLOAT
L, NOTES
1. SEED AND PLACE MATTING FOR EROSION CONTROL ON INTERIOR AND EXTERIOR SIDESLOPES.
2. INSTALL A MINIMUM OF 3 COIR FIBER BAFFLES IN ACCORDANCE WITH PRACTICE STANDARD 6.65,
l 1a90'9S 3. INSTALL SKIMMER AND COUPLING TO RISER STRUCTURE OR DIRECTLY INTO EMBANKMENT 1 FT. FROM BOTTOM OF BASIN, A'
4.THE ARM PIPE SHALL HAVE A MINIMUM LENGTH OF 6 FT. BETWEEN THE SKIMMER AND COUPLING. NOT TO SCALE I V
k1 Section AA
Filter
TOP VIEW OlOnnet
Figure 6.41t Rip•:p aY.lnl p,aocten imrJdwa hor+vz tiWi':':
SEDIMENT BASIN SKIMMER AND RISER DETAIL
SEDIMENT BASIN SKIMMER DETAIL PIPE OUTLET STABILIZATION STRUCTURE (PRACTICE 6.64)
(PRACTICE 6.41) NOT TO SCALE
NOT TO SCALE P
H LET C H ___
__ •�\\AL I� IE�M[I A IIRL IETM KINGS MOUNTAIN
DRAFTSPERSON D. LAMECH NR 8-30-23 --- C 0 R P 0 R A T 1 0 N 348 HOLIDAY INN DRIVE
DESIGNER D. LAMECH NR 8-30-23 --- KINGS MOUNTAIN, NC 28286 CHECKER S. ALUGUVELD This drawing is the confidential property of Albemarle Corporation and is issued with the express understanding and agreement that it Q
__ --- is not to be copied or reproduced,or used in any way detrimental to the interest of Albemarle Corporation and is to be returned on request.
RESP. ENNO.G.
ISSUED FOR PERMITTING DESIGN T. KAISER
S. ALUGuvELu MINING AND CONCENTRATOR FACILITY
LEAD DISC. EN .S. ALUGUVELD E ISSUED FOR PERMITTING JT SA CC 04-03-24
MINE SELECT PHASE
ENG. MANAGER D ISSUED FOR SELECT JT SA CC 12-15-23 EROSION AND SEDIMENT CONTROL
PROD. MANAGER K. YOUNG
C DL SA CC 11-30-23
FOR CLIENT REVIEW TYPICAL DETAILS
NOT FOR CONSTRUCTION
ROLE NAME SIGNATURE DATE B FOR DL SA CC 10-06-23
INTERNAL REVIEW JOB NO. DRAFTER: DRAWING NO. SHT. 1 of 1 REVISION R
F KM22040 D. LAMECH
ORINTERNAL REVIEW
A DL SA CC 8-30-23 SCALE: DATE K M 61 —C I—D T-0 0101 E
HATCH DRAWING NUMBER: H371132-4100-222-292-0002
REV# DESCRIPTION CADD CHK'D APPR'D DATE NTS 8-30-23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
A
FACE VIEW OF CONCRETE
OUTFALL ANCHOR
SLOPE ABOVE THE ANCHOR
B � CONCRETE BLOCK
REVETMENT SYSTEMS
B
C
Q� REFE ENCE
Q� POIN
D
SECTION VIEW E
OF CONCRETE
B �
NORMAL POOL
PERMANENT CONCRETE OUTFALL ANCHOR
F
ROLLED EROSION CONTROL
PRODUCT , 18'
NOTES: PLAN VIEW
1 . CLASS 1 EXCAVATION , CLASS A CONCRETE , TRIMMING OUTFALL PIPE , GEOTEXTILE CLASS 4 TYPE A AND 12 „ G
COMPACTED SUBGRAGE ARE INCIDENTAL TO THE DRAINAGE OUTFALL WITH CONCRETE BLOCK REVETMENT SYSTEMS. OUTFALL PIPE
2. PERMANENT EROSION CONTROL AND SEEDING IS INCIDENTAL TO THE OUTFALL CONSTRUCTION.
EXPOSED CONCRETE FACE CONCRETE OUTFALL
ANCHOR
VARIES
( MATCH CONCRETE OUTFALL ANCHOR H
EXISTING)
CLASS A CONCRETE ON
B �I TOP OF REVETMENT CONCRETE BLOCK
REVETMENT SYSTEMS
TRIM OUTFALL PIPE
FLUSH WITH SLOPE
GEOTEXTILE AS SPECIFIED
\ REFERENCE BY MANUFACTURER SECTION B-B
\ POINT ( AT ALL GROUND CONTACT)
OUTFALL PIPE
\ K
\ /o, 18
CLASS A CONCRETE �ij EXISTING GRADE CONCRETE BLOCK
( INCIDENTAL TO CONCRETE OUTFALL ANCHOR) 4; REVETMENT SYSTEM
D .• . D .• . D .• . D .• . D .• . D .• . D .• o D o D .• . D .• . D .• . D .• O D 1�" D.• . .• -
CONCRETE BLOCK - - -
D \ REVETMENT SYSTEMS =�II�I� II�I-ICI-I 18 " I�. I I� ,
\ VARIES
� D D D D D D e \ ( MATCH ,,;IIII I-II -II I I III L
�X 1ST 1 NG)
D D D • D D D ' III- - - - - -III
I �J \ BACKFILL OPEN AREA WITH bill iil-Ill—��I—lit-, -
• 1 ' D ' D ' D ' Do B TOPSOIL SEED AND MULCH
J1 2, ( AT ILE 9 CLASS 4 9 T) PE A
• D � D BACKFILL OPEN AREA WITH
1 SECTION A-A TOPSOIL , SEED AND MULCH
GEOTEXT I LE , CLASS 4 , TYPE A M
( AT ALL GROUND CONTACT)
COMPACTED SUBGRADE
NORMAL POOL
PROFILE \
(DRAINAGE OUTFALL) MATCH EXISTING INCONCRETE BLOCK REVETMENT SYSTEMS ,q�
(OR EQUIVALENT) TYPICAL DETAIL
NOT TO SCALE
P
HL\TCH ___ ___
ALBEMARLETM KINGS MOUNTAIN
DRAFTSPERSON E. 1MOREK0 NR 02 14 24 -- ___ I AC 0 R P 0 R A T 1 0 N 348 HOLIDAY INN DRIVE
DESIGNER E. MORERO NR C2 14 24 --- KINGS MOUNTAIN, NC 28286 Q
CHECKER S. 4,_000\,/-LU This drawing is the confidential property of Albemarle Corporation and is issued with the express understanding and agreement that it
DESIGN COORD. T. KAISER is not to be copied or reproduced,or used in any way detrimental to the interest of Albemarle Corporation and is to be returned on request.
ISSUED F 0 R PERMITTING RESP. ENG. S. A_u0u��-Eu -_- ___ MINING AND CONCENTRATOR FACILITY
LEAD DISC. ENG. S. ALUGUVLLU MINE SELECT PHASE
ENG. MANAGER --- EROSION AND SEDIMENT CONTROL
NOT FOR CONSTRUCTION PROD. MANAGER K. C YOUNG ISSUED FOR PERMITTING
ELM SRA TPK 04/03/24 TYPICAL DETAILS
ROLE NAME SIGNATURE DATE B ELM SRA TPK 04/02/24 INTERNAL&CLIENT REVIEW JOB NO. DRAFTER: DRAWING NO. SHT. 1 of 1 REVISION R
INTERNAL&CLIENT REVIEW KM22040 E. MORENO
A ELM SRA TPK 02/23/24 KM61 —CI-DT-00104 C
HATCH DRAWING NUMBER: H371132-4100-222-292-0004 --- SCALE: DATE
REV# DESCRIPTION CADD CHK'D APPR'D DATE AS NOTED 02/14/24

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
L
A A
NOTES:
1. USE FOR APRONS SERVING CULVERTS WITH SLOPES OF
LESS THAN 10%.
PROTECTIVE APRON DIMENSIONS AND ESTIMATED QUANTITIES 2. FOR ARCH OR ELLIPTICAL PIPES, USE EQUIVALENT
DIAMETER FOR (D) DIMENSION.
OUTLET WITHOUT 3. SEE TABLE BELOW FOR DIMENSIONS AND ESTIMATED
DITCH OUTLET WITH DITCH QUANTITIES.
HEADWALL AND LENGTH OF DEPTH OF ESTIMATED ESTIMATED ESTIMATED ESTIMATED
CULVERT RIPRAP APRON L RIPRAP GEOTEXTILE RIPRAP GEOTEXTILE
WINGWALL - SIZE (D) O APRON (H)
INCHES CLASS LNFT LNFT QUANTITY QUANTITY QUANTITY QUANTITY
CUYD SQYD CUYD SQYD C
12 2 4 1.5 1.6 6 1.1 6.3
_ 18 2 6 1.5 3 10 2.5 11.1
WITH HEADWALL 24 2 8 1.5 5.3 16 4.5 17
AND WINGWALL 30 3 12.5 2 15 32 11.6 32
B 36 3 15 2 21.7 43 16.7 42.6
D
o M o 42 4 21 2.5 47.6 73 34.1 68.4
N
48 4 24 2.5 62.2 91 44.5 84.9
- o
-- E
RADIUS = D (TYP.) F
G
A
PLAN VIEW H
SCALE: NTS
EXISTING GROUND VARIES J
4D (MIN.)
�qR EXISTING
4 GROUND
SLOP`Op£ L 1 H V•E .2
OR FLATTER
VARIABLE SLOPE
D/2 (min.)
L
H (min.)
GEOTEXTILE, CLASS 1, TYPE C
FLOWLINE
HEADWALL AND GEOTEXTILE, CLASS 1 , TYP C M
WINGWALL
SECTION B - B SECTION A-A
SCALE: NITS SCALE: NITS
N
CULVERT WITH HEADWALL AND WINGWALL
PROTECTIVE APRON AT CULVERT OUTLET WITH DITCH P
H LET C H ___ --
--- --- --- KINGS MOUNTAIN
DRAFTSPERSON D. LAMECH NR 1 1 —1 —202 J)1C 0 R P 0 R A T 1 0 N ALBEMARLE 348 HOLIDAY INN DRIVE
ISSUED FOR P E RM I TT I N DESIGNER D. LAMECH NR 1 1 —1 —202 --- KINGS MOUNTAIN, NC 28286
--- --- --- -- Q
CHECKER S. ALUGUVELLI ___ This drawing is the confidential property of Albemarle Corporation and is issued with the express understanding and agreement that it
- --- --- --- --- is not to be copied or reproduced,or used in any way detrimental to the interest of Albemarle Corporation and is to be returned on request.
DESIGN COORD. T. KAISER ---
RESP. ENG. S. ALUGUVELLI -- MINE AND CONCENTRATOR FACILITY
LEAD DISC. ENG. S. ALUGUVELLI
MINE SELECT PHASE
ENG. MANAGER C. CLARKE D DL SRA TPK 07-05-24 CLIENT REVIEW PROTECTIVE APRON AT CULVERT
&PERMITTING
NOT FOR CONSTRUCTION PROD. MANAGER K.YOUNG OUTLET WITH DITCH
C ISSUED FOR SELECT JT SA CC 12-15-23
ROLE NAME SIGNATURE DATE B FOR CLIENT REVIEW DL SA CC 11-30-23 JOB NO. DRAFTER: DRAWING NO. SHT. 1 of 1 REVISION R
KM22040 D. LAMECH
HATCH DRAWING NUMBER: H37113241002222920003 A FOR INTERNAL REVIEW DL SA CC 11-01-23 SCALE: DATE KM61 -CI-DT-00103 D
REV# DESCRIPTION CADD CHK'D APPR'D DATE NTS 11-1-2023

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
A
B
C
TRENCH
WIDTH AS LANE D
DEFINED BY �RovN
STD. NO. - 1
PROVIDE SUITABLE PROTECTION
UNDISTURBED I BEING WASHED TO PREVENT OUT
LBYFROM
EARTH I -
N SURFACE WATER
SUBDRA/N. EXTEND E
12 < 12" ABOVE FINISH GRADE. v (MIN)
MIN. MIN. w z CONCRETE ANCHOR „
BASIN RISER 18 PLANTING MIX (TYPICAL) — 3N 1
IF - TOP OF BASIN OUTLET STRUCTURE (MIN. 60 )
A I PIPE , I I I I < STORM WA TER
CONCRETE I - —— `3y'�l� EARTHEN BERM z INLET PIPE
ANCHOR L _ BELL OR III-III _ �j�j SUBDRAIN DISCHARGE F
N z WELDED SLEEVE 1-III-III-III-= ��
��—ITI=ITI=1 i I=1I�_— L o cA TioN � ------ ----
_ _ RIP—RAP
�I I MI
UNDISTURBED -III-III-III-I I I-I I MI I I 6" ----- ---------
EARTH 6" MIN. 12" FOR PIPES 12" IN DIA. OR LESS �-III-III-III-III-III-III
ADDITIONAL -III-III-III-III-III-III _ _
CONCRETE EXCAVATION 18" FOR PIPES 15" TO 21 " IN DIA. _ _
ANCHOR -1 I I-1 I I-I 11-I I I-I 11-1 I I (PONDIBASIN BOTTOMS " -1 I I— I I=1I
TBRENNCH 24" FOR PIPES 24" TO 30" IN DIA.ELOW �,I III=III=III=III=III �8 I1-_III G
-III-III-III-III-III CLASS 3 GEOTEXTILE FABRIC
TRENCH WALLT11.1-III-III-III-III - ,_2 -I
=1I1=III=1I1=1II=111 - - -
-
12" _
- - _- - j-
SECTION A-A III=1 11=1 11=1 11=1 11=1 11=1 I I=1 11=1 11=1 I MI 11-1 I I-I I I-1 I I-1 I I-1 I I-1 I I-1 I I-1 I I=1 I I=1 I I=1 I I=1 I I=1 I I=1 I I I I III=1 I I III=1 I I , ,I I 1=1 11=1 11=1 11=1 I I I I I
MIN.
=1 I=1 I I=1 I I=1 I I=1 "I I I-I 11-1 II ' 9 2" AGGREGATE STORAGE LAYER:
1=1 11=1 11=1 11=1 11=1 11=1 I I-1 I I-1 I I-1 I I-1 1511 I-1 11=1 11=1 11=1 11=1 11=1 11=1 11=1 11=1 11=1 11=1 I I-1 I I-1 I I-1 I I-1 I I-1 I I-1 I I-1 I I I I-1 I I III I I 1=1 I I I I 1=1 I I-I I-III III III III,; 9 CLASS 2 PERMEABLE WITH 3
,III, ,III ,III;III;III;III-1 I I-1 I I-1 I I-1 11-1 11-1 11-1 11-1 11-1 I I-III-III-I I I_I I I_I I I_I I I_I I I III-1 I I-III„ I I„I I I I-,III„ I I;,I 11, I I I I I I I I I i i I I I I I I I I I I I I I-
PEA GRAVEL FILTER COURSE H
CONCRETE ANCHORS FOR PIPES ON STEEP GRADES _III—III L30 MIL PVC LINER LAYER AT THE TOP. CLASS 3
OUTFLOW PIPE (IMPERMEABLE). PERMEABLE �c PEA GRAVEL SHALL
(CONCRETE ANCHORS TO BE SET AT JOINTS AS SHOWN): (TO KINGS CREEK) BE WASHED AND FREE OF FINES
PROVIDE NO ANCHORS ON GRADES LESS THAN 20% UNLESS NOTED BOTTOM MIN. 3" AGGREGATE
PROVIDE ANCHORS AT MAX. 36' C TO C ON GRADES BETWEEN 20% AND UP TO 35% BELOW SUBDRAIN J
PROVIDE ANCHORS AT MAX. 24' C TO C ON GRADES BETWEEN 35% AND UP TO 50%
PROVIDE ANCHORS AT MAX. 16' C TO C ON GRADES BETWEEN 50% AND 70% STORMWATER DETENTION BASIN DET141L SEC TI ON A - A
1 . FOR CONDITIONS OTHER THAN SHOWN HEREIN ANCHORS SHALL BE
PROVIDED AS REQUIRED BY THE CONTRACT PLANS OR ORDERED NOT TO SCALE
IN THE FIELD BY THE OWNER'S REPRESENTATIVE
2. FULL LENGTHS OF PIPE SHALL BE USED. PIPE SHALL BE CUT TO K
MEET THE C/C ANCHOR PLACEMENT REQUIREMENTS. MINIMUM LENGTH
OF CUT PIPE SHALL BE 6'.
3. EXCAVATE BEYOND TRENCH WIDTH AND DEPTH AS SHOWN ABOVE
AND POUR CONCRETE AGAINST UNDISTURBED EARTH
4. 4000 PSI AIR-ENTRAINED CONCRETE
L
M
N
P
HATCH ___ ___
ALBEMARLETM KINGS MOUNTAIN
DRAFTSPERSON E. MORENO NR 02 14 24 -- C 0 R P 0 R A T 1 0 N 348 HOLIDAY INN DRIVE
DESIGNER E. MORENO NR 02 1 4 24 --- --- KINGS MOUNTAIN, NC 28286 CHECKER S. ALUGUVELD This drawing is the confidential property of Albemarle Corporation and is issued with the express understanding and agreement that it Q
DESIGN COORD. T. KAISER --- --- is not to be copied or reproduced,or used in any way detrimental to the interest of Albemarle Corporation and is to be returned on request.
RESP. ENG. S. ALUGUVELD --- MINING AND CONCENTRATOR FACILITY
ISSUED F 0 R PERMITTING LEAD DISC. ENG. S. ALUGUVELD --- --- SITE WIDE
ENG. MANAGER --- STORMWATER DETENTION POND
NOT FOR CONSTRUCTION PROD. MANAGER K. YOUNG ISSUED FOR PERMITTING
C ELM SRA TPK 04/03/24 TYPICAL DETAILS
B ELM SRA TPK 04/02/24
ROLE NAME SIGNATURE DATE INTERNAL&CLIENT REVIEW JOB NO. DRAFTER: DRAWING NO. SHT. 1of1 REVISION R
INTERNAL&CLIENT REVIEW KM22040 E. MORENO
A ELM SRA TPK 02/23/24 SCALE: DATE KM61 —CI—DT-00105 C
HATCH DRAWING NUMBER: H371132-4100-222-292-0005
REV# DESCRIPTION CADD CHK'D APPR'D DATE AS NOTED 02/14/24

ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Appendix A:
Frequency Analysis Results from AWA &
NOAA Atlas 14 Precipitation Map
H371132-4000-220-230-0001, Rev. C
©Hatch 2024 All rights reserved,including all rights relating to the use of this document or its contents.

FREQUENCY ANALYSIS RESULTS FROM AWA (2022)
Table 10.5: Kings Mountain basin overall frequencN anaiN sis for 6-,24-,and 72-hour
Kings Mnt Frequency Analysis 6-hour 24-hour 72-hour
ARI & AEF AEP 50% 5% 95% 50% S% 95% 50% 5% 95%
1.01 0.913010 9.9- 1.0 0.9 1.1 2.o 1.8 2.2 2.4 2.2 2.6
2 0.50ma 5.0- 2.3 2.1 2.5 3.6 3.4 3.9 4.3 4.0 4.6
S 0.20000 2.0- 3.2 2.9 3.4 4.8 4.4 S.1 5.7 5.2 6.1
10 0.1-0000 1.0- 3.8 3.S 4.1 5.5 5.1 &0 6.6 6.1 7.1
25 0.04000 4.0"' 4.7 4.3 5.0 6.6 6.1 7.2 7.9 7.3 8.5
50 0.02000 2.0-' 5.3 4.9 5.8 7.5 6.9 8.2 8.9 9.2 9.7
100 0.01000 1.0-, &0 S.S 6.7 8.4 7.7 9.2 9.9 9.1 10.9
200 0.005o0 5.0'' 6.9 6.2 7.6 9.3 85 10.4 11.0 10.1 12.3
500 0.00200 2.0"' 7.9 7.1 8.9 10.6 9.6 12.1 12.6 11.4 14.3
1,000 0.00100 1.0" 9.7 7.8 10.1 11.7 10.4 13.5 13.9 12.4 16.0
5,000 0.00020 2.0-1 10.9 9.5 13.1 14.4 12.S 17.2 17.1 14.9 20.4
10,000 0.3H]010 1.0-` 11.9 10.3 14.5 15.7 13.S 19.1 18.6 16.0 22.6
100,000 0.00001 1.0" 15.9 13.1 20.5 20.4 16.9 26.5 24.2 20.0 31.3
1,000,000 0,000001 1.0"E 20.S 16.3 28.3 26.2 20.7 36.1 31.0 24.5 42.7
10,000,000 0.0000001 1.0" 26.2 19.9 38.7 33.1 25.0 48.8 39.1 29.7 57.8
100,000,000 0.00000001 1.0-` 33.1 24.0 52.5 41.3 29.9 65.5 48.9 35.4 77.6
1,000,000,000 0.000000001 1.0-' 41A 28.6 70.7 51.2 35.3 87.4 60.6 41.9 103.5
10,000,000,000 0.00001 1.0-" S1.4 339 94.7 63.1 41.S 116.1 74.7 49.2 137.5

www.nws.noaa.gov
* aA's Naboo a I Weather Service A EAr,
f Will
A.,/ Hydrometeorological Design Studies Cenli-ir
Precipitation Frequency Data Server (PFDS)
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General Information NOAA ATLAS 14 POINT PRECIPITATION FREQUENCY ESTIMATES: NC
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Glossary Data type: Precipitation depth v Units: English v Time series type: Partial duration V
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Kin9spgrt
contact us I�70 — Location information:
Inquiries i Johnzon{:I7'� 0 0 0 0 ■ ■ Name:Gastonia,North Carolina,
■ � USA'
L*.r 0 l 5
C1 [� 0p.1--�iora ++riill`I�0 �■ ■ ■ Station name:GASTONIA
KnaxWjEl � L'� 0.Rce Mount
-9 .. El 0 �,leit h b ■■ Site ID:31-3356
0�0 it• 00 ED% �� 0 El J 0 ■ Latitude:35.2625'
� 0 0 0 0 �en"' Longitude:-81.1219°
0 0 l� '� 0 t] El
0 ■El
Elevation:700 ft
El �, El 0 �.t.h a rl�tt=Cr ID 0
- m Lo 1�J::11 0.0 0 1.1' 0,$1}'ette':II�Ir. ■.
- Z*1 Grecri le ■ �+ 0 LI
a 0 0 0 0 Jackson
0 0 ■
Wilmington
mbis
Athens � a � ■
11 is outh
Ca�lina
__,,Aucgucta
ti `Source:ESRI Maps

I100km .. .ii North I - "Source:USGS
Charreston �J
60 m' Mt Pl easan t
POINT PRECIPITATION FREQUENCY (PF) ESTIMATES
WITH 90%CONFIDENCE INTERVALS AND SUPPLEMENTARY INFORMATION
NOAA Atlas 14,Volume 2,Version 3
PF tabular PF graphical Supplementary intormati
8 Print page
PDS-based precipitation frequency estimates with 90%confidence intervals(in inches)'
Average recurrence interval(years)
1 2 5 10 25 50 100 200 500 1000
5-min 0.394 0.466 0.544 0.601 0.669 0.717 0.761 0.802 0.850 0.885
(0.364-0.427) 1 (0.429-0.507) (0.500-0.591) 1 (0.552-0.652) (0.611-0.725) (0.651-0.776) (0.687-0.825) (0.719-0.871) (0.753-0.926) (0.777-0.967)
10-min 0.629 7F 0.744 7F 0.871 7F 0.962 7F 1.27 1.34 1.39
(0.581-0.682) (0.687-0.810) (0.801-0.947) (0.882-1.04) (0.973-1.16) (1.04-1.24) (1.09-1.31) (1.14-1.38) (1.19-1.46) (1.22-1.52)
5-min 0.787 0.936
1 1.10 1.22 1.35 1.44 1.53 1.60 1.69 1.75
(0.727-0.853) (0.863-1.02) (1.01-1.20) (1.12-1.32) (1.23-1.46) (1.31-1.57) (1.38-1.66) (1.44-1.74) (1.50-1.84)
30-min 1.08 1.29 1.56 1.76 2.00 2.18 2.34 2.50 2.69 2.83
(0.996-1.17) (1.19-1.41) (1.44-1.70) (1.62-1.91) (1.83-2.17) (1.98-2.36) (2.12-2.54) (2.24-2.71) (2.39-2.93) (2.49-3.10)
Ed1.34 1.62 2.01 2.30 2.66 2.95 3.23 3.50 3.86 4.14(1.24-1.46) (1.50-1.76) (1.84-2.18) (2.11-2.49) (2.43-2.89) (2.68-3.20) (2.91-3.50) (3.14-3.80) (3.42-4.21) (3.63-4.52)
2-hr 1.57 1.90 2.36 2.72 3.19 3.55 3.92 4.29 4.79 5.18
(1.44-1.72) (1.73-2.08)
3-hr 1 1.67 2.01 2.52 2.92 3.46 3.90 4.34 4.80 5.44 5.96(1.84-2.22) (2.30-2.77) (2.65-3.20) (3.13-3.80) (3.50-4.27) (3.87-4.76) (4.24-5.28) (4.74-6.00) (5.12-6.59)
6-hr 2.04 2.45 3.06 3.55 4.22 4.76 5.31 5.89 6.71 7.36
(1.87-2.23) (2.25-2.69) (2.81-3.36) (3.24-3.88) (3.83-4.60) (4.29-5.19) (4.75-5.80) (5.22-6.44) (5.85-7.34) (6.33-8.07)
12-hr 2.44 2.94 3.68 4.28 5.11 5.78 6.48 7.22 8.25 9.09
(2.25-2.66) (2.71-3.22) (3.38-4.02) (3.91-4.67) (4.64-5.56) (5.21-6.28) (5.79-7.03) (6.37-7.83) (7.17-8.95) (7.80-9.88)
24-hr 2.81F 3.39 4.26 4.94 5.87F 6.62 7.38 8.16 9.23 10.1
(2.62-3.02) (3.17-3.65) (3.97-4.57) (4.60-5.30) (5.45-6.30) (6.13-7.09) (6.81-7.90) (7.51-8.74) (8.46-9.89) .
2-day 3.31 3.98 4.97 5.74 6.80 7.64 8.49 9.36 10.6 115
(3.09-3.55) (3.72-4.28) (4.63-5.33) (5.34-6.16) (6.31-7.29) (7.07-8.18) (7.84-9.10) (8.63-10.0) (9.69-11.3) (10.5-12.4)
3-day 3.51F 4.22 F 6.03 F 7.99 F 9.78
(3.28-3.76) (3.95-4.52) (4.89-5.60) (5.62-6.46) (6.62-7.62) (7.41-8.55) (8.21-9.49) (9.02-10.5) 10.1-11.8 11.0-12.8
4-day 3.72 4.46 5.50 6.32 7.45F 8.34 9.25F 10.2 11.5 12.5
(3.48-3.97) (4.18-4.77) 1 (5.14-5.87) (5.90-6.75) (6.93-7.95) (7.74-8.91) (8.57-9.89) (9.42-10.9)
7-day 4 4.28 5.10 6.21 7.09 8.30 9.27 10.2 ) ( 11.3 ) ( 12.6 ) ( 13.7. )
(4.79-5.42) (5.83-6.59) (6.65-7.52) (7.76-8.81) (8.64-9.84) (9.54-10.9 10.4-12.0 11.7-13.4 12.6-146
10-day 4.90 5.82 7.00 7.92 9.16 10.1 11.1F 12.1 13.5 14.5
(4.62-5.21) (5.49-6.19) 1 (6.60-7.44) (7.46-8.41) (8.61-9.72) (9.50-10.8) (10.4-11.8) (11.3-12.9)
20-day 6.56 7.74 9.14 10.2 F 16.8 18.1
(6.21-6.94) (7.33-8.19) (8.64-9.66) (9.68-10.8) (11.0-12.4) (12.1-13.6) (13.2-14.9) (14.3-16.1) (15.7-17.9)
30-day 8.08 9.51 17.1 12.3 73.8 75.0 16.2 17.4F 19.0 20.2
(7.688.51) (9.02-10.0) (10.5-11.6) (11.6-12.9) (13.1-14.6) (14.2-15.8) (15.3-17.1) (16.4-18.4) (17.8-20.1) (18.9-21.4)
45-day 10.2 11.9 13.6 14.9 16.6 17.9 19.1 20.3 21.9 23.1
(9.71-10.6) (11.4-12.4) 11 (13.0-14.2) (14.2-15.6) 1 (15.8-17.3)
60-day 12.1 14.1 15.9 17.3 19.1 20.5 21.8 23.1 24.7 26.0
(116-12.6) (1314.1 7) (15.2-16.6) (16.6-18.1) (18.3-20.0) (19.6-21.4)
t Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS).

I100km .. .ii North I - "Source:USGS
Charreston �J
60 m' Mt Pl easan t
POINT PRECIPITATION FREQUENCY (PF) ESTIMATES
WITH 90%CONFIDENCE INTERVALS AND SUPPLEMENTARY INFORMATION
NOAA Atlas 14,Volume 2,Version 3
PF tabular PF graphical Supplementary information
8 Print page
PDS-based precipitation frequency estimates with 90%confidence intervals(in inches/hour)
Average recurrence interval(years)
1 2 5 10 25 50 100 200 500 1000
5-min 4.73 5.59 6.53 7.21 8.03 8.60 9.13 9.62 10.2 10.6
(4.37-5.12) (5.15-6.08) (6.00-7.09) (6.62-7.82) (7.33-8.70) (7.81-9.31) (8.24-9.90) (8.63-10.5) (9.04-11.1) (9.32-11.6)
10-min 3.77 4.46 7 F 6.40 6.85 F 8.07 7F 8.36
(3.49 4.09) (4.12-4.86) (4.81-5.68) (5.29-6.26) (5.84-6.93) (6.22-7.42) (6.55-7.87) (6.83-8.29) (7.15-8.79) 1 (7.34-9.14)
15-min 3.15 3.74 4.40 4.86 5.40 5.78 6.12 6.41 6.77F 7.00
(2.91-3.41) (3.454.07) (4.05-4.79) (4.46-5.28) (4.94-5.86) (5.25-6.26) (5.52-6.63) (5.75-6.97) (6.00-7.38) (6.14-7.65)
30-min 2.16 2.59 3.13 3.53 4.00 4.35 4.68 4.99 5.39 5.66
(1.99-2.34) (2.38-2.81) (2.88-3.40) (3.23-3.82) (3.65-4.34) (3.95-4.72) (4.23-5.08) (4.47-5.42) (4.77-5.87) (4.97-6.19)
60-min 1.34 1.62 2.01 2.30 2.66 F 3.50 3.86
(1.24-1.46) (1.50-1.76) (1.84-2.18) (2.11-2.49) 11 (2.43-2.89) (2.68-3.20) (2.91-3.50) (3.14-3.80) (3.42-4.21) (3.63-4.52
2-hr 0.783 0.948 1.18 1.36 1.59 1.78 1.96 2.15 2.40 2.59
(0.717-0.858) (0.867-1.04) (1.08-1.29) (1.24-1.48) (1.44-1.74) (1.60-1.94) (1.76-2.14) (1.91-2.35) (2.10-2.64) (2.25-2.86)
3-hr 0.556 0.670 0.838 0.970 1.15 1.30 F 1.60 F 1.98
(0.508-0.612) (0.613-0.737) (0.765-0.922) (0.883-1.06) (1.04-1.26) (1.16-1.42) (1.29-1.58) (1.41-1.76) (1.58-2.00) (1.70-2.19)
6-hr 0.340 0.408 0.511 0.592 0.704 0.794 0.887 0.984 1.12 1.23
(0.312-0.372) (0.375-0.448) (0.468-0.561) (0.541-0.648) (0.639-0.768) (0.716-0.866) (0.793-0.968) (0.871-1.08) (---1- (1.0.754 )
12-hr 0.202 0.243 0.305 0.355 0.423 0.479 0.537 0.598 0.684 0.754
(0.186-0.220) (0.224-0.267) (0.280-0.334) (0.324-0.387) (0.385-0.461) (0.432-0.521) (0.480-0.583) (0.528-0.649) (0.595-0.742) (0.647-0.819)
24-hr 0.117 0.141 0.177 0.206 0.244 0.275 0.307 0.340 0.384 0.419
(0.109-0.125) (0.132-0.151) (0.165-0.190) (0.191-0.220) (0.227-0.262) (0.255-0.295) (0.283-0.329) (0.312-0.364) (0.352-0.412) (0.383-0.449)
2-day 0.068 0.082 0.103 0.119 0.141 0.159 0.176 0.195 0.220 0.239
(0.064-0.073) (0.077-0.089) (0.096-0.111) (0.111-0.128) (0.131-0.151) (0.147-0.170) (0.163-0.189) (0.179-0.209) (0.201-0.236) (0.219-0.257)
3-day 0.048 0.058 0.072 0.083 0.098 0.110 0.123 0.135 0.152 0.166(0.045-0.052) (0.054-0.062) (0.067-0.077) (0.078-0.089) (0.091-0.105) (0.102-0.118) (0.113-0.131) (0.125-0.145) (0.140-0.163) (0.152-0.178)
4-day 0.038 0.046 0.057 0.065 0.077 0.086 0.096 0.106 0.119 0.129
(0.036-0.041) (0.043-0.049) (0.053-0.061) (0.061-0.070) (0.072-0.082) (0.080-0.092) (0.089-0.102) (0.098-0.113) (0.110-0.127) (0.119-0.138)
7-day 0.025 0.030 0.036 0.042 0.049 0.055 0.061 0.067 0.075 0.081(0.023-0.027) (0.028-0.032) (0.034-0.039) (0.039-0.044) (0.046-0.052) (0.051-0.058) (0.056-0.064) (0.062-0.071) (0.069-0.079) (0.075-0.086)
10-day 0.020 0.024 0.029 0.033 0.038 0.042 0.046 0.050 0.056 0.060
(0.019-0.021) (0.022-0.025) (0.027-0.030) (0.031-0.035) (0.035-0.040) (0.039-0.044) (0.043-0.049) (0.047-0.053) (0.052-0.059) (0.056-0.064)
20-day 0.013 0.016 0.019 0.021 0.024 0.026 0.029 0.031 0.035 0.037
(0.012-0.014) (0.015-0.017) (0.018-0.020) (0.020-0.022) (0.023-0.025) (0.025-0.028) (0.027-0.030) (0.029-0.033) (0.032-0.037) (0.034-0.039)
30-day 0.071 0.013 0.015 0.017 0.019 0.020 0.022 0.024 0.026 0.028
(0.010 0.011) (0.012-0.013) (0.014-0.016) (0.016-0.017) (0.018-0.020) (0.019-0.021) (0.021-0.023) (0.022-0.025) (0.024-0.027) (0.026-0.029)
5-day 0.009 0.011 0.012 0.013 0.015 0.016 0.017 0.018 0.020 0.021
4
(0.008-0.009) (0.010-0.011) (0.011-0.013) (0.013-0.014) (0.014-0.016) (0.015-0.017) (0.016-0.018) (0.017-0.019) (0.019-0.021) (0.020-0.022)
60-day 0.008 0.009 0.011 0.012 0.013 0.014 0.015 0.016 0.017 0.018 )
(0.008-0.008) (0.009-0.010) (0.010-0.011) (0.011-0.012) (0.012-0.013) (0.013-0.014) (0.014-0.015) (0.015-0.016) (0.016-0.017) (0.017-0.018
t Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS).

ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Appendix B:
Summary Peak Runoff Volume and Flowrate
Calculations for Phase 1 BMPs
H371132-4000-220-230-0001, Rev. C
©Hatch 2024 All rights reserved,including all rights relating to the use of this document or its contents.

1
Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
C5 C �
4
E5
ffx:5
Legend
Hyd• Origin Description
1 SCS Runoff Existing-Phase 1A
2 SCS Runoff Existing-Phase 1 B
3 SCS Runoff Existing-Phase 1C
4 Combine Existing Areas Combined
5 SCS Runoff Existing-Phase 2B
6 SCS Runoff Existing-Phase 2A
7 Reach DP at Basin 1
8 SCS Runoff Existing-Phase 2B1 9
9 Combine DA-4A and B
10 SCS Runoff Existing-3A(NPI)
11 SCS Runoff Existing-3B(NPI)
12 SCS Runoff OSF-1
13 SCS Runoff OSF-2
14 SCS Runoff OSF-3
15 SCS Runoff OSF-3
Project: Construction SWM-R1.gpw Wednesday, 07/ 10/2024

Hydraflow Table of Contents ConstructionSWM-R1.gpw
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Watershed Model Schematic...................................................................................... 1
Hydrograph Return Period Recap............................................................................. 2
2 - Year
SummaryReport......................................................................................................................... 3
HydrographReports................................................................................................................... 4
Hydrograph No. 1, SCS Runoff, Existing-Phase 1A................................................................. 4
TR-55 Tc Worksheet........................................................................................................... 5
Hydrograph No. 2, SCS Runoff, Existing-Phase 1 B................................................................. 6
TR-55 Tc Worksheet........................................................................................................... 7
Hydrograph No. 3, SCS Runoff, Existing-Phase 1 C................................................................ 8
TR-55 Tc Worksheet........................................................................................................... 9
Hydrograph No. 4, Combine, Existing Areas Combined........................................................ 10
Hydrograph No. 5, SCS Runoff, Existing-Phase 2B............................................................... 11
TR-55 Tc Worksheet......................................................................................................... 12
Hydrograph No. 6, SCS Runoff, Existing-Phase 2A............................................................... 13
TR-55 Tc Worksheet......................................................................................................... 14
Hydrograph No. 7, Reach, DP at Basin 1............................................................................... 15
Hydrograph No. 8, SCS Runoff, Existing-Phase 2B1............................................................. 16
TR-55 Tc Worksheet......................................................................................................... 17
Hydrograph No. 9, Combine, DA-4A and B............................................................................ 18
Hydrograph No. 10, SCS Runoff, Existing-3A (NPI)............................................................... 19
TR-55 Tc Worksheet......................................................................................................... 20
Hydrograph No. 11, SCS Runoff, Existing-3B(NPI)................................................................ 21
TR-55 Tc Worksheet......................................................................................................... 22
Hydrograph No. 12, SCS Runoff, OSF-1............................................................................... 23
TR-55 Tc Worksheet......................................................................................................... 24
Hydrograph No. 13, SCS Runoff, OSF-2............................................................................... 25
TR-55 Tc Worksheet......................................................................................................... 26
Hydrograph No. 14, SCS Runoff, OSF-3............................................................................... 27
TR-55 Tc Worksheet......................................................................................................... 28
Hydrograph No. 15, SCS Runoff, OSF-3............................................................................... 29
TR-55 Tc Worksheet......................................................................................................... 30
10 - Year
SummaryReport....................................................................................................................... 31
HydrographReports................................................................................................................. 32
Hydrograph No. 1, SCS Runoff, Existing-Phase 1A............................................................... 32
Hydrograph No. 2, SCS Runoff, Existing-Phase 1 B............................................................... 33
Hydrograph No. 3, SCS Runoff, Existing-Phase 1 C.............................................................. 34
Hydrograph No. 4, Combine, Existing Areas Combined........................................................ 35
Hydrograph No. 5, SCS Runoff, Existing-Phase 2B............................................................... 36
Hydrograph No. 6, SCS Runoff, Existing-Phase 2A............................................................... 37
Hydrograph No. 7, Reach, DP at Basin 1............................................................................... 38
Hydrograph No. 8, SCS Runoff, Existing-Phase 2B1............................................................. 39
Hydrograph No. 9, Combine, DA-4A and B............................................................................ 40
Hydrograph No. 10, SCS Runoff, Existing-3A (NPI)............................................................... 41

Contents Continued... ConstructionSWM-R1.gpw
Hydrograph No. 11, SCS Runoff, Existing-3B(NPI)................................................................ 42
Hydrograph No. 12, SCS Runoff, OSF-1............................................................................... 43
Hydrograph No. 13, SCS Runoff, OSF-2............................................................................... 44
Hydrograph No. 14, SCS Runoff, OSF-3............................................................................... 45
Hydrograph No. 15, SCS Runoff, OSF-3............................................................................... 46
25 - Year
SummaryReport....................................................................................................................... 47
HydrographReports................................................................................................................. 48
Hydrograph No. 1, SCS Runoff, Existing-Phase 1A............................................................... 48
Hydrograph No. 2, SCS Runoff, Existing-Phase 1 B............................................................... 49
Hydrograph No. 3, SCS Runoff, Existing-Phase 1 C.............................................................. 50
Hydrograph No. 4, Combine, Existing Areas Combined........................................................ 51
Hydrograph No. 5, SCS Runoff, Existing-Phase 2B............................................................... 52
Hydrograph No. 6, SCS Runoff, Existing-Phase 2A............................................................... 53
Hydrograph No. 7, Reach, DP at Basin 1............................................................................... 54
Hydrograph No. 8, SCS Runoff, Existing-Phase 2B1............................................................. 55
Hydrograph No. 9, Combine, DA-4A and B............................................................................ 56
Hydrograph No. 10, SCS Runoff, Existing-3A (NPI)............................................................... 57
Hydrograph No. 11, SCS Runoff, Existing-3B(NPI)................................................................ 58
Hydrograph No. 12, SCS Runoff, OSF-1............................................................................... 59
Hydrograph No. 13, SCS Runoff, OSF-2............................................................................... 60
Hydrograph No. 14, SCS Runoff, OSF-3............................................................................... 61
Hydrograph No. 15, SCS Runoff, OSF-3............................................................................... 62
100 - Year
SummaryReport....................................................................................................................... 63
HydrographReports................................................................................................................. 64
Hydrograph No. 1, SCS Runoff, Existing-Phase 1A............................................................... 64
Hydrograph No. 2, SCS Runoff, Existing-Phase 1 B............................................................... 65
Hydrograph No. 3, SCS Runoff, Existing-Phase 1 C.............................................................. 66
Hydrograph No. 4, Combine, Existing Areas Combined.............................................
Hydrograph No. 5, SCS Runoff, Existing-Phase 2B............................................................... 68
Hydrograph No. 6, SCS Runoff, Existing-Phase 2A............................................................... 69
Hydrograph No. 7, Reach, DP at Basin 1............................................................................... 70
Hydrograph No. 8, SCS Runoff, Existing-Phase 2B1............................................................. 71
Hydrograph No. 9, Combine, DA-4A and B............................................................................ 72
Hydrograph No. 10, SCS Runoff, Existing-3A (NPI)............................................................... 73
Hydrograph No. 11, SCS Runoff, Existing-3B(NPI)................................................................ 74
Hydrograph No. 12, SCS Runoff, OSF-1............................................................................... 75
Hydrograph No. 13, SCS Runoff, OSF-2............................................................................... 76
Hydrograph No. 14, SCS Runoff, OSF-3............................................................................... 77
Hydrograph No. 15, SCS Runoff, OSF-3............................................................................... 78

2
Hydrograph Return Period Recce
draflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. Hydrograph Inflow Peak Outflow(cfs) Hydrograph
No. type hyd(s) Description
(origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
1 SCS Runoff ------ 0.003 0.634 ------- ------- 5.052 8.674 ------- 15.46 Existing-Phase 1A
2 SCS Runoff ------ 0.050 4.763 ------- ------- 25.36 41.77 ------- 72.20 Existing-Phase 1B
3 SCS Runoff ------ 0.031 2.881 ------- ------- 16.80 28.30 ------- 49.96 Existing-Phase 1C
4 Combine 2, 3 0.525 6.746 ------- ------- 37.12 61.84 ------- 109.24 Existing Areas Combined
5 SCS Runoff ------ 0.000 0.558 ------- ------- 6.097 11.60 ------- 22.95 Existing-Phase 2B
6 SCS Runoff ------ 0.156 9.382 ------- ------- 38.89 60.85 ------- 100.88 Existing-Phase 2A
7 Reach 6 2.728 7.554 ------- ------- 30.12 47.93 ------- 80.89 DP at Basin 1
8 SCS Runoff ------ 0.000 0.153 ------- ------- 1.473 2.721 ------- 5.253 Existing-Phase 2131
9 Combine 5,8 0.088 0.448 ------- ------- 4.861 9.714 ------- 20.02 DA-4A and B
10 SCS Runoff ------ 0.065 4.466 ------- ------- 24.92 42.59 ------- 77.27 Existing-3A(NPI)
11 SCS Runoff ------ 0.023 1.567 ------- ------- 8.741 14.94 ------- 27.11 Existing-3B(NPI)
12 SCS Runoff ------ 0.000 1.252 ------- ------- 11.57 21.84 ------- 43.19 OSF-1
13 SCS Runoff ------ 0.000 0.902 ------- ------- 8.476 16.03 ------- 31.71 OSF-2
14 SCS Runoff ------ 0.000 0.340 ------- ------- 3.449 6.563 ------- 12.99 OSF-3
15 SCS Runoff ------ 0.000 0.419 ------- ------- 4.251 8.089 ------- 16.01 OSF-3
Proj. file: Construction SWM-R1.gpw Wednesday, 07/ 10/2024

3
Hydrograph Summary Report Hydraf low Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 0.634 2 728 4,658 ------ ------ ------ Existing-Phase 1A
2 SCS Runoff 4.763 2 736 37,355 ------ ------ ------ Existing-Phase 1B
3 SCS Runoff 2.881 2 740 26,647 ------ ------ ------ Existing-Phase 1C
4 Combine 6.746 2 738 59,203 2, 3 ------ ------ Existing Areas Combined
5 SCS Runoff 0.558 2 758 9,366 ------ ------ ------ Existing-Phase 2B
6 SCS Runoff 9.382 2 738 68,102 ------ ------ ------ Existing-Phase 2A
7 Reach 7.554 1 741 60,289 6 ------ ------ DP at Basin 1
8 SCS Runoff 0.153 2 752 2,196 ------ ------ ------ Existing-Phase 2131
9 Combine 0.448 2 764 8,978 5,8 ------ ------ DA-4A and B
10 SCS Runoff 4.466 2 784 70,784 ------ ------ ------ Existing-3A(NPI)
11 SCS Runoff 1.567 2 784 24,831 ------ ------ ------ Existing-3B(NPI)
12 SCS Runoff 1.252 2 780 24,362 ------ ------ ------ OSF-1
13 SCS Runoff 0.902 2 778 17,314 ------ ------ ------ OSF-2
14 SCS Runoff 0.340 2 766 6,088 ------ ------ ------ OSF-3
15 SCS Runoff 0.419 2 766 7,504 ------ ------ ------ OSF-3
Construction SWM-R1.gpw Return Period: 2 Year Wednesday, 07/ 10/2024

4
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 1
Existing-Phase 1A
Hydrograph type = SCS Runoff Peak discharge = 0.634 cfs
Storm frequency = 2 yrs Time to peak = 12.13 hrs
Time interval = 2 min Hyd. volume = 4,658 cuft
Drainage area = 4.700 ac Curve number = 52*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 15.40 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.350 x 55)+(2.350 x 48)]/4.700
Existing-Phase 1A
Q (cfs) Hyd. No. 1 --2 Year Q (cfs)
1.00 1.00
0.90 0.90
0.80 0.80
0.70 0.70
0.60 0.60
0.50 0.50
0.40 0.40
0.30 0.30
0.20 0.20
0.10 0.10
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

5
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 1
Existing-Phase 1A
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.41 0.00 0.00
Land slope (%) = 5.00 0.00 0.00
Travel Time (min) = 14.42 + 0.00 + 0.00 = 14.42
Shallow Concentrated Flow
Flow length (ft) = 150.00 120.00 0.00
Watercourse slope (%) = 7.30 11.00 0.00
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =4.36 5.35 0.00
Travel Time (min) = 0.57 + 0.37 + 0.00 = 0.95
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 15.40 min

6
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 2
Existing-Phase 1 B
Hydrograph type = SCS Runoff Peak discharge = 4.763 cfs
Storm frequency = 2 yrs Time to peak = 12.27 hrs
Time interval = 2 min Hyd. volume = 37,355 cuft
Drainage area = 27.100 ac Curve number = 55*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 29.10 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(19.300 x 55)+(8.270 x 56)]/27.100
Existing-Phase 1 B
Q (cfs) Hyd. No. 2 --2 Year Q (cfs)
5.00 5.00
4.00 4.00
3.00 lit 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

7
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 2
Existing-Phase 1 B
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.41 0.00 0.00
Land slope (%) = 4.00 0.00 0.00
Travel Time (min) = 15.77 + 0.00 + 0.00 = 15.77
Shallow Concentrated Flow
Flow length (ft) = 750.00 800.00 200.00
Watercourse slope (%) = 1.30 2.70 2.00
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =1.84 2.65 2.28
Travel Time (min) = 6.79 + 5.03 + 1.46 = 13.28
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 29.10 min

8
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 3
Existing-Phase 1 C
Hydrograph type = SCS Runoff Peak discharge = 2.881 cfs
Storm frequency = 2 yrs Time to peak = 12.33 hrs
Time interval = 2 min Hyd. volume = 26,647 cuft
Drainage area = 21.000 ac Curve number = 54*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 33.70 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(15.100 x 55)+(3.600 x 48)]/21.000
Existing-Phase 1 C
Q (cfs) Hyd. No. 3 --2 Year Q (cfs)
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 3 Time (hrs)

9
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 3
Existing-Phase 1 C
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 200.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.14 0.00 0.00
Land slope (%) = 4.00 0.00 0.00
Travel Time (min) = 28.60 + 0.00 + 0.00 = 28.60
Shallow Concentrated Flow
Flow length (ft) = 350.00 350.00 300.00
Watercourse slope (%) = 7.70 6.90 1.60
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =4.48 4.24 2.04
Travel Time (min) = 1.30 + 1.38 + 2.45 = 5.13
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 33.70 min

10
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 4
Existing Areas Combined
Hydrograph type = Combine Peak discharge = 6.746 cfs
Storm frequency = 2 yrs Time to peak = 12.30 hrs
Time interval = 2 min Hyd. volume = 59,203 cuft
Inflow hyds. = 2, 3 Contrib. drain. area = 48.100 ac
Existing Areas Combined
Q (cfs) Hyd. No. 4 --2 Year Q (cfs)
7.00 7.00
6.00 6.00
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 4 Hyd No. 2 Hyd No. 3

11
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 5
Existing-Phase 2B
Hydrograph type = SCS Runoff Peak discharge = 0.558 cfs
Storm frequency = 2 yrs Time to peak = 12.63 hrs
Time interval = 2 min Hyd. volume = 9,366 cuft
Drainage area = 13.510 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 36.00 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(11.300 x 48)+(2.210 x 56)]/13.510
Existing-Phase 2113
Q (cfs) Hyd. No. 5 --2 Year Q (cfs)
1.00 1.00
0.90 0.90
0.80 0.80
0.70 0.70
0.60 0.60
0.50 0.50
0.40 0.40
0.30 0.30
0.20 0.20
0.10 0.10
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 5 Time (hrs)

12
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 5
Existing-Phase 2B
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 200.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.41 0.00 0.00
Land slope (%) = 3.50 0.00 0.00
Travel Time (min) = 28.95 + 0.00 + 0.00 = 28.95
Shallow Concentrated Flow
Flow length (ft) = 400.00 500.00 375.00
Watercourse slope (%) = 6.50 9.00 1.10
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =4.11 4.84 1.69
Travel Time (min) = 1.62 + 1.72 + 3.69 = 7.04
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 36.00 min

13
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 6
Existing-Phase 2A
Hydrograph type = SCS Runoff Peak discharge = 9.382 cfs
Storm frequency = 2 yrs Time to peak = 12.30 hrs
Time interval = 2 min Hyd. volume = 68,102 cuft
Drainage area = 38.500 ac Curve number = 58*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 36.00 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(19.750 x 48)+(8.780 x 56)+(5.610 x 69)+(2.000 x 98)+(2.360 x 85)]/38.500
Existing-Phase 2A
Q (cfs) Hyd. No. 6 --2 Year Q (cfs)
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 6 Time (hrs)

14
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 6
Existing-Phase 2A
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 200.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.41 0.00 0.00
Land slope (%) = 3.50 0.00 0.00
Travel Time (min) = 28.95 + 0.00 + 0.00 = 28.95
Shallow Concentrated Flow
Flow length (ft) = 400.00 500.00 375.00
Watercourse slope (%) = 6.50 9.00 1.10
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =4.11 4.84 1.69
Travel Time (min) = 1.62 + 1.72 + 3.69 = 7.04
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 36.00 min

15
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 7
DP at Basin 1
Hydrograph type = Reach Peak discharge = 7.554 cfs
Storm frequency = 2 yrs Time to peak = 12.35 hrs
Time interval = 1 min Hyd. volume = 60,289 cuft
Inflow hyd. No. = 6 - Existing-Phase 2A Section type = Trapezoidal
Reach length = 400.0 ft Channel slope = 5.0 %
Manning's n = 0.015 Bottom width = 5.0 ft
Side slope = 4.0:1 Max. depth = 1.0 ft
Rating curve x = 7.592 Rating curve m = 1.135
Ave. velocity = 0.00 ft/s Routing coeff. = 0.7849
Modified Att-Kin routing method used.
DP at Basin 1
Q (cfs) Q (cfs)
Hyd. No. 7 --2 Year
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 7 Hyd No. 6

16
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 8
Existing-Phase 2B1
Hydrograph type = SCS Runoff Peak discharge = 0.153 cfs
Storm frequency = 2 yrs Time to peak = 12.53 hrs
Time interval = 2 min Hyd. volume = 2,196 cuft
Drainage area = 2.710 ac Curve number = 50*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 30.60 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.000 x 48)+(0.710 x 56)]/2.710
Existing-Phase 21131
Q (cfs) Hyd. No. 8 --2 Year Q (cfs)
0.50 0.50
0.45 0.45
0.40 0.40
0.35 0.35
0.30 0.30
0.25 0.25
0.20 0.20
0.15 0.15
Irk
0.10 0.10
0.05 0.05
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 8 Time (hrs)

17
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 8
Existing-Phase 2131
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 200.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.41 0.00 0.00
Land slope (%) = 3.50 0.00 0.00
Travel Time (min) = 28.95 + 0.00 + 0.00 = 28.95
Shallow Concentrated Flow
Flow length (ft) = 400.00 0.00 0.00
Watercourse slope (%) = 6.50 0.00 0.00
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =4.11 0.00 0.00
Travel Time (min) = 1.62 + 0.00 + 0.00 = 1.62
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 30.60 min

18
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 9
DA-4A and B
Hydrograph type = Combine Peak discharge = 0.448 cfs
Storm frequency = 2 yrs Time to peak = 12.73 hrs
Time interval = 2 min Hyd. volume = 8,978 cuft
Inflow hyds. = 5, 8 Contrib. drain. area = 16.220 ac
DA-4 and B
Q (cfs) Hyd. N It --2 Year Q (cfs)
0.50 0.50
0.45 0.45
0.40 0.40
It
0.35 0.35
0.30 0.30
0.25 0.25
0.20 0.20
0.15 0.15
0.10 0.10
0.05 0.05
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 9 Hyd No. 5 Hyd No. 8

19
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 10
Existing-3A (NPI)
Hydrograph type = SCS Runoff Peak discharge = 4.466 cfs
Storm frequency = 2 yrs Time to peak = 13.07 hrs
Time interval = 2 min Hyd. volume = 70,784 cuft
Drainage area = 63.000 ac Curve number = 53*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 75.70 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(28.000 x 55)+(22.500 x 56)+(51.000 x 48)+(3.500 x 98)]/63.000
Existing-3A (NPI)
Q (cfs) Hyd. No. 10 --2 Year Q (cfs)
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 10 Time (hrs)

20
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 10
Existing-3A (NPI)
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 300.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.41 0.00 0.00
Land slope (%) = 1.00 0.00 0.00
Travel Time (min) = 66.10 + 0.00 + 0.00 = 66.10
Shallow Concentrated Flow
Flow length (ft) = 490.00 750.00 475.00
Watercourse slope (%) = 2.20 6.70 2.30
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =2.39 4.18 2.45
Travel Time (min) = 3.41 + 2.99 + 3.24 = 9.64
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 75.70 min

21
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 11
Existing-3B(NPI)
Hydrograph type = SCS Runoff Peak discharge = 1.567 cfs
Storm frequency = 2 yrs Time to peak = 13.07 hrs
Time interval = 2 min Hyd. volume = 24,831 cuft
Drainage area = 22.100 ac Curve number = 53*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 75.70 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(28.000 x 55)+(22.500 x 56)+(51.000 x 48)+(3.500 x 98)]/22.100
Existing-3113(NPI)
Q (cfs) Hyd. No. 11 --2 Year Q (cfs)
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 11 Time (hrs)

22
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 11
Existing-3B(NPI)
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 300.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.41 0.00 0.00
Land slope (%) = 1.00 0.00 0.00
Travel Time (min) = 66.10 + 0.00 + 0.00 = 66.10
Shallow Concentrated Flow
Flow length (ft) = 490.00 750.00 475.00
Watercourse slope (%) = 2.20 6.70 2.30
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =2.39 4.18 2.45
Travel Time (min) = 3.41 + 2.99 + 3.24 = 9.64
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 75.70 min

23
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 12
OSF-1
Hydrograph type = SCS Runoff Peak discharge = 1.252 cfs
Storm frequency = 2 yrs Time to peak = 13.00 hrs
Time interval = 2 min Hyd. volume = 24,362 cuft
Drainage area = 35.000 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 56.00 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.500 x 55)+(2.400 x 56)+(30.100 x 48)]/35.000
OSF-1
Q (cfs) Hyd. No. 12 --2 Year Q (cfs)
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 12

24
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 12
OSF-1
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 200.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.41 0.00 0.00
Land slope (%) = 1.00 0.00 0.00
Travel Time (min) = 47.79 + 0.00 + 0.00 = 47.79
Shallow Concentrated Flow
Flow length (ft) = 250.00 300.00 350.00
Watercourse slope (%) = 1.50 1.00 1.50
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =1.98 1.61 1.98
Travel Time (min) = 2.11 + 3.10 + 2.95 = 8.16
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 56.00 min

25
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 13
OSF-2
Hydrograph type = SCS Runoff Peak discharge = 0.902 cfs
Storm frequency = 2 yrs Time to peak = 12.97 hrs
Time interval = 2 min Hyd. volume = 17,314 cuft
Drainage area = 24.500 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 53.20 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(1.500 x 55)+(2.500 x 56)+(20.500 x 48)]/24.500
OSF-2
Q (cfs) Hyd. No. 13 --2 Year Q (cfs)
1.00 1.00
0.90 0.90
0.80 0.80
0.70 0.70
0.60 0.60
0.50 V0.50
0.40 0.40
0.30 0.30
0.20 0.20
0.10 0.10
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 13

26
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 13
OSF-2
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 200.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.41 0.00 0.00
Land slope (%) = 1.00 0.00 0.00
Travel Time (min) = 47.79 + 0.00 + 0.00 = 47.79
Shallow Concentrated Flow
Flow length (ft) = 250.00 200.00 150.00
Watercourse slope (%) = 1.50 1.00 1.50
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =1.98 1.61 1.98
Travel Time (min) = 2.11 + 2.07 + 1.27 = 5.44
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 53.20 min

27
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 14
OSF-3
Hydrograph type = SCS Runoff Peak discharge = 0.340 cfs
Storm frequency = 2 yrs Time to peak = 12.77 hrs
Time interval = 2 min Hyd. volume = 6,088 cuft
Drainage area = 8.600 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 41.60 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(0.600 x 55)+(0.500 x 56)+(7.500 x 48)]/8.600
OSF-3
Q (cfs) Hyd. No. 14 --2 Year Q (cfs)
0.50 0.50
0.45 0.45
0.40 0.40
0.35 0.35
0.30 0.30
0.25 0.25
0.20 0.20
0.15 0.15
0.10 0.10
0.05 0.05
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 14

28
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 14
OSF-3
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 150.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.41 0.00 0.00
Land slope (%) = 1.00 0.00 0.00
Travel Time (min) = 37.97 + 0.00 + 0.00 = 37.97
Shallow Concentrated Flow
Flow length (ft) = 150.00 250.00 0.00
Watercourse slope (%) = 1.00 1.50 0.00
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =1.61 1.98 0.00
Travel Time (min) = 1.55 + 2.11 + 0.00 = 3.66
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 41.60 min

29
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 15
OSF-3
Hydrograph type = SCS Runoff Peak discharge = 0.419 cfs
Storm frequency = 2 yrs Time to peak = 12.77 hrs
Time interval = 2 min Hyd. volume = 7,504 cuft
Drainage area = 10.600 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 41.60 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(0.600 x 55)+(0.500 x 56)+(9.500 x 48)]/10.600
OSF-3
Q (cfs) Hyd. No. 15 --2 Year Q (cfs)
0.50 0.50
0.45 0.45
0.40 0.40
0.35 0.35
0.30 0.30
0.25 0.25
0.20 0.20
0.15 0.15
0.10 0.10
0.05 0.05
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 15

30
TR55 Tc Worksheet
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. No. 15
OSF-3
Description A B C Totals
Sheet Flow
Manning's n-value = 0.400 0.240 0.240
Flow length (ft) = 150.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.41 0.00 0.00
Land slope (%) = 1.00 0.00 0.00
Travel Time (min) = 37.97 + 0.00 + 0.00 = 37.97
Shallow Concentrated Flow
Flow length (ft) = 150.00 250.00 0.00
Watercourse slope (%) = 1.00 1.50 0.00
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =1.61 1.98 0.00
Travel Time (min) = 1.55 + 2.11 + 0.00 = 3.66
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.025 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 41.60 min

31
Hydrograph Summary Report Hydraf low Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 5.052 2 724 17,236 ------ ------ ------ Existing-Phase 1A
2 SCS Runoff 25.36 2 732 121,911 ------ ------ ------ Existing-Phase 1B
3 SCS Runoff 16.80 2 736 90,324 ------ ------ ------ Existing-Phase 1C
4 Combine 37.12 2 734 191,441 2, 3 ------ ------ Existing Areas Combined
5 SCS Runoff 6.097 2 738 40,974 ------ ------ ------ Existing-Phase 2B
6 SCS Runoff 38.89 2 736 200,849 ------ ------ ------ Existing-Phase 2A
7 Reach 30.12 1 739 166,163 6 ------ ------ DP at Basin 1
8 SCS Runoff 1.473 2 736 9,035 ------ ------ ------ Existing-Phase 2131
9 Combine 4.861 2 740 37,018 5,8 ------ ------ DA-4A and B
10 SCS Runoff 24.92 2 764 250,773 ------ ------ ------ Existing-3A(NPI)
11 SCS Runoff 8.741 2 764 87,969 ------ ------ ------ Existing-3B(NPI)
12 SCS Runoff 11.57 2 752 106,581 ------ ------ ------ OSF-1
13 SCS Runoff 8.476 2 750 75,747 ------ ------ ------ OSF-2
14 SCS Runoff 3.449 2 744 26,636 ------ ------ ------ OSF-3
15 SCS Runoff 4.251 2 744 32,831 ------ ------ ------ OSF-3
Construction SWM-R1.gpw Return Period: 10 Year Wednesday, 07/ 10/2024

32
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 1
Existing-Phase 1A
Hydrograph type = SCS Runoff Peak discharge = 5.052 cfs
Storm frequency = 10 yrs Time to peak = 12.07 hrs
Time interval = 2 min Hyd. volume = 17,236 cuft
Drainage area = 4.700 ac Curve number = 52*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 15.40 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.350 x 55)+(2.350 x 48)]/4.700
Existing-Phase 1A
Q (cfs) Hyd. No. 1 -- 10 Year Q (cfs)
6.00 6.00
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

33
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 2
Existing-Phase 1 B
Hydrograph type = SCS Runoff Peak discharge = 25.36 cfs
Storm frequency = 10 yrs Time to peak = 12.20 hrs
Time interval = 2 min Hyd. volume = 121,911 cuft
Drainage area = 27.100 ac Curve number = 55*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 29.10 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(19.300 x 55)+(8.270 x 56)]/27.100
Existing-Phase 1 B
Q (cfs) Hyd. No. 2 -- 10 Year Q (cfs)
28.00 28.00
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

34
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 3
Existing-Phase 1 C
Hydrograph type = SCS Runoff Peak discharge = 16.80 cfs
Storm frequency = 10 yrs Time to peak = 12.27 hrs
Time interval = 2 min Hyd. volume = 90,324 cuft
Drainage area = 21.000 ac Curve number = 54*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 33.70 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(15.100 x 55)+(3.600 x 48)]/21.000
Existing-Phase 1 C
Q (cfs) Hyd. No. 3 -- 10 Year Q (cfs)
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 3 Time (hrs)

35
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 4
Existing Areas Combined
Hydrograph type = Combine Peak discharge = 37.12 cfs
Storm frequency = 10 yrs Time to peak = 12.23 hrs
Time interval = 2 min Hyd. volume = 191,441 cuft
Inflow hyds. = 2, 3 Contrib. drain. area = 48.100 ac
Existing Areas Combined
Q (cfs) Hyd. No. 4 -- 10 Year Q (cfs)
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 - 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 4 Hyd No. 2 Hyd No. 3

36
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 5
Existing-Phase 2B
Hydrograph type = SCS Runoff Peak discharge = 6.097 cfs
Storm frequency = 10 yrs Time to peak = 12.30 hrs
Time interval = 2 min Hyd. volume = 40,974 cuft
Drainage area = 13.510 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 36.00 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(11.300 x 48)+(2.210 x 56)]/13.510
Existing-Phase 2113
Q (cfs) Hyd. No. 5 -- 10 Year Q (cfs)
7.00 7.00
6.00 A 6.00
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 5 Time (hrs)

37
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 6
Existing-Phase 2A
Hydrograph type = SCS Runoff Peak discharge = 38.89 cfs
Storm frequency = 10 yrs Time to peak = 12.27 hrs
Time interval = 2 min Hyd. volume = 200,849 cuft
Drainage area = 38.500 ac Curve number = 58*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 36.00 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(19.750 x 48)+(8.780 x 56)+(5.610 x 69)+(2.000 x 98)+(2.360 x 85)]/38.500
Existing-Phase 2A
Q (cfs) Hyd. No. 6 -- 10 Year Q (cfs)
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
77t77��
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 6 Time (hrs)

38
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 7
DP at Basin 1
Hydrograph type = Reach Peak discharge = 30.12 cfs
Storm frequency = 10 yrs Time to peak = 12.32 hrs
Time interval = 1 min Hyd. volume = 166,163 cuft
Inflow hyd. No. = 6 - Existing-Phase 2A Section type = Trapezoidal
Reach length = 400.0 ft Channel slope = 5.0 %
Manning's n = 0.015 Bottom width = 5.0 ft
Side slope = 4.0:1 Max. depth = 1.0 ft
Rating curve x = 7.592 Rating curve m = 1.135
Ave. velocity = 0.00 ft/s Routing coeff. = 0.8644
Modified Att-Kin routing method used.
DP at Basin 1
Q (cfs) Hyd. No. 7 -- 10 Year Q (cfs)
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 7 — Hyd No. 6

39
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 8
Existing-Phase 2B1
Hydrograph type = SCS Runoff Peak discharge = 1.473 cfs
Storm frequency = 10 yrs Time to peak = 12.27 hrs
Time interval = 2 min Hyd. volume = 9,035 cuft
Drainage area = 2.710 ac Curve number = 50*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 30.60 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.000 x 48)+(0.710 x 56)]/2.710
Existing-Phase 21131
Q (cfs) Hyd. No. 8 -- 10 Year Q (cfs)
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 8 Time (hrs)

40
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 9
DA-4A and B
Hydrograph type = Combine Peak discharge = 4.861 cfs
Storm frequency = 10 yrs Time to peak = 12.33 hrs
Time interval = 2 min Hyd. volume = 37,018 cuft
Inflow hyds. = 5, 8 Contrib. drain. area = 16.220 ac
DA- and B
Q (cfs) Hyd. N 9 -- 10 Year Q (cfs)
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 9 Hyd No. 5 Hyd No. 8

41
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 10
Existing-3A (NPI)
Hydrograph type = SCS Runoff Peak discharge = 24.92 cfs
Storm frequency = 10 yrs Time to peak = 12.73 hrs
Time interval = 2 min Hyd. volume = 250,773 cuft
Drainage area = 63.000 ac Curve number = 53*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 75.70 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(28.000 x 55)+(22.500 x 56)+(51.000 x 48)+(3.500 x 98)]/63.000
Existing-3A (NPI)
Q (cfs) Hyd. No. 10-- 10 Year Q (cfs)
28.00 28.00
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 10 Time (hrs)

42
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 11
Existing-3B(NPI)
Hydrograph type = SCS Runoff Peak discharge = 8.741 cfs
Storm frequency = 10 yrs Time to peak = 12.73 hrs
Time interval = 2 min Hyd. volume = 87,969 cuft
Drainage area = 22.100 ac Curve number = 53*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 75.70 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(28.000 x 55)+(22.500 x 56)+(51.000 x 48)+(3.500 x 98)]/22.100
Existing-3113(NPI)
Q (cfs) Hyd. No. 11 -- 10 Year Q (cfs)
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 11 Time (hrs)

43
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 12
OSF-1
Hydrograph type = SCS Runoff Peak discharge = 11.57 cfs
Storm frequency = 10 yrs Time to peak = 12.53 hrs
Time interval = 2 min Hyd. volume = 106,581 cuft
Drainage area = 35.000 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 56.00 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.500 x 55)+(2.400 x 56)+(30.100 x 48)]/35.000
OSF-1
Q (cfs) Hyd. No. 12-- 10 Year Q (cfs)
12.00 12.00
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 12

44
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 13
OSF-2
Hydrograph type = SCS Runoff Peak discharge = 8.476 cfs
Storm frequency = 10 yrs Time to peak = 12.50 hrs
Time interval = 2 min Hyd. volume = 75,747 cuft
Drainage area = 24.500 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 53.20 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(1.500 x 55)+(2.500 x 56)+(20.500 x 48)]/24.500
OSF-2
Q (cfs) Hyd. No. 13-- 10 Year Q (cfs)
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 13

45
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 14
OSF-3
Hydrograph type = SCS Runoff Peak discharge = 3.449 cfs
Storm frequency = 10 yrs Time to peak = 12.40 hrs
Time interval = 2 min Hyd. volume = 26,636 cuft
Drainage area = 8.600 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 41.60 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(0.600 x 55)+(0.500 x 56)+(7.500 x 48)]/8.600
OSF-3
Q (cfs) Hyd. No. 14 -- 10 Year Q (cfs)
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
— Hyd No. 14 Time (hrs)

46
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 15
OSF-3
Hydrograph type = SCS Runoff Peak discharge = 4.251 cfs
Storm frequency = 10 yrs Time to peak = 12.40 hrs
Time interval = 2 min Hyd. volume = 32,831 cuft
Drainage area = 10.600 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 41.60 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(0.600 x 55)+(0.500 x 56)+(9.500 x 48)]/10.600
OSF-3
Q (cfs) Hyd. No. 15-- 10 Year Q (cfs)
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 15

47
Hydrograph Summary Report Hydraf low Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 8.674 2 724 26,881 ------ ------ ------ Existing-Phase 1A
2 SCS Runoff 41.77 2 732 184,374 ------ ------ ------ Existing-Phase 1B
3 SCS Runoff 28.30 2 734 137,934 ------ ------ ------ Existing-Phase 1C
4 Combine 61.84 2 732 290,757 2, 3 ------ ------ Existing Areas Combined
5 SCS Runoff 11.60 2 738 66,309 ------ ------ ------ Existing-Phase 2B
6 SCS Runoff 60.85 2 736 295,889 ------ ------ ------ Existing-Phase 2A
7 Reach 47.93 1 738 244,393 6 ------ ------ DP at Basin 1
8 SCS Runoff 2.721 2 736 14,435 ------ ------ ------ Existing-Phase 2131
9 Combine 9.714 2 738 60,330 5,8 ------ ------ DA-4A and B
10 SCS Runoff 42.59 2 762 386,890 ------ ------ ------ Existing-3A(NPI)
11 SCS Runoff 14.94 2 762 135,719 ------ ------ ------ Existing-3B(NPI)
12 SCS Runoff 21.84 2 750 172,483 ------ ------ ------ OSF-1
13 SCS Runoff 16.03 2 748 122,582 ------ ------ ------ OSF-2
14 SCS Runoff 6.563 2 742 43,106 ------ ------ ------ OSF-3
15 SCS Runoff 8.089 2 742 53,131 ------ ------ ------ OSF-3
Construction SWM-R1.gpw Return Period: 25 Year Wednesday, 07/ 10/2024

48
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 1
Existing-Phase 1A
Hydrograph type = SCS Runoff Peak discharge = 8.674 cfs
Storm frequency = 25 yrs Time to peak = 12.07 hrs
Time interval = 2 min Hyd. volume = 26,881 cuft
Drainage area = 4.700 ac Curve number = 52*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 15.40 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.350 x 55)+(2.350 x 48)]/4.700
Existing-Phase 1A
Q (cfs) Hyd. No. 1 --25 Year Q (cfs)
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

49
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 2
Existing-Phase 1 B
Hydrograph type = SCS Runoff Peak discharge = 41.77 cfs
Storm frequency = 25 yrs Time to peak = 12.20 hrs
Time interval = 2 min Hyd. volume = 184,374 cuft
Drainage area = 27.100 ac Curve number = 55*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 29.10 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(19.300 x 55)+(8.270 x 56)]/27.100
Existing-Phase 1 B
Q (cfs) Hyd. No. 2 --25 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

50
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 3
Existing-Phase 1 C
Hydrograph type = SCS Runoff Peak discharge = 28.30 cfs
Storm frequency = 25 yrs Time to peak = 12.23 hrs
Time interval = 2 min Hyd. volume = 137,934 cuft
Drainage area = 21.000 ac Curve number = 54*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 33.70 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(15.100 x 55)+(3.600 x 48)]/21.000
Existing-Phase 1 C
Q (cfs) Hyd. No. 3 --25 Year Q (cfs)
30.00 30.00
25.00 25.00
20.00 20.00
15.00 15.00
10.00 10.00
5.00 5.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 3 Time (hrs)

51
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 4
Existing Areas Combined
Hydrograph type = Combine Peak discharge = 61.84 cfs
Storm frequency = 25 yrs Time to peak = 12.20 hrs
Time interval = 2 min Hyd. volume = 290,757 cuft
Inflow hyds. = 2, 3 Contrib. drain. area = 48.100 ac
Existing Areas Combined
Q (cfs) Hyd. No. 4 --25 Year Q (cfs)
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 4 Hyd No. 2 Hyd No. 3

52
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 5
Existing-Phase 2B
Hydrograph type = SCS Runoff Peak discharge = 11.60 cfs
Storm frequency = 25 yrs Time to peak = 12.30 hrs
Time interval = 2 min Hyd. volume = 66,309 cuft
Drainage area = 13.510 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 36.00 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(11.300 x 48)+(2.210 x 56)]/13.510
Existing-Phase 2113
Q (cfs) Hyd. No. 5 --25 Year Q (cfs)
12.00 12.00
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 5 Time (hrs)

53
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 6
Existing-Phase 2A
Hydrograph type = SCS Runoff Peak discharge = 60.85 cfs
Storm frequency = 25 yrs Time to peak = 12.27 hrs
Time interval = 2 min Hyd. volume = 295,889 cuft
Drainage area = 38.500 ac Curve number = 58*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 36.00 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(19.750 x 48)+(8.780 x 56)+(5.610 x 69)+(2.000 x 98)+(2.360 x 85)]/38.500
Existing-Phase 2A
Q (cfs) Hyd. No. 6 --25 Year Q (cfs)
70.00 70.00
60.00 A 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 6 Time (hrs)

54
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 7
DP at Basin 1
Hydrograph type = Reach Peak discharge = 47.93 cfs
Storm frequency = 25 yrs Time to peak = 12.30 hrs
Time interval = 1 min Hyd. volume = 244,393 cuft
Inflow hyd. No. = 6 - Existing-Phase 2A Section type = Trapezoidal
Reach length = 400.0 ft Channel slope = 5.0 %
Manning's n = 0.015 Bottom width = 5.0 ft
Side slope = 4.0:1 Max. depth = 1.0 ft
Rating curve x = 7.592 Rating curve m = 1.135
Ave. velocity = 0.00 ft/s Routing coeff. = 0.8916
Modified Att-Kin routing method used.
DP at Basin 1
Q (cfs) Hyd. No. 7 --25 Year Q (cfs)
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 7 Hyd No. 6

55
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 8
Existing-Phase 2B1
Hydrograph type = SCS Runoff Peak discharge = 2.721 cfs
Storm frequency = 25 yrs Time to peak = 12.27 hrs
Time interval = 2 min Hyd. volume = 14,435 cuft
Drainage area = 2.710 ac Curve number = 50*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 30.60 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.000 x 48)+(0.710 x 56)]/2.710
Existing-Phase 21131
Q (cfs) Hyd. No. 8 --25 Year Q (cfs)
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 8 Time (hrs)

56
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 9
DA-4A and B
Hydrograph type = Combine Peak discharge = 9.714 cfs
Storm frequency = 25 yrs Time to peak = 12.30 hrs
Time interval = 2 min Hyd. volume = 60,330 cuft
Inflow hyds. = 5, 8 Contrib. drain. area = 16.220 ac
DA- A and B
Q (cfs) Hyd. N 9 --25 Year Q (cfs)
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 9 Hyd No. 5 Hyd No. 8

57
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 10
Existing-3A (NPI)
Hydrograph type = SCS Runoff Peak discharge = 42.59 cfs
Storm frequency = 25 yrs Time to peak = 12.70 hrs
Time interval = 2 min Hyd. volume = 386,890 cuft
Drainage area = 63.000 ac Curve number = 53*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 75.70 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(28.000 x 55)+(22.500 x 56)+(51.000 x 48)+(3.500 x 98)]/63.000
Existing-3A (NPI)
Q (cfs) Hyd. No. 10--25 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 10 Time (hrs)

58
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 11
Existing-3B(NPI)
Hydrograph type = SCS Runoff Peak discharge = 14.94 cfs
Storm frequency = 25 yrs Time to peak = 12.70 hrs
Time interval = 2 min Hyd. volume = 135,719 cuft
Drainage area = 22.100 ac Curve number = 53*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 75.70 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(28.000 x 55)+(22.500 x 56)+(51.000 x 48)+(3.500 x 98)]/22.100
Existing-3113(NPI)
Q (cfs) Hyd. No. 11 --25 Year Q (cfs)
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 11 Time (hrs)

59
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 12
OSF-1
Hydrograph type = SCS Runoff Peak discharge = 21.84 cfs
Storm frequency = 25 yrs Time to peak = 12.50 hrs
Time interval = 2 min Hyd. volume = 172,483 cuft
Drainage area = 35.000 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 56.00 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.500 x 55)+(2.400 x 56)+(30.100 x 48)]/35.000
OSF-1
Q (cfs) Hyd. No. 12--25 Year Q (cfs)
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 12

60
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 13
OSF-2
Hydrograph type = SCS Runoff Peak discharge = 16.03 cfs
Storm frequency = 25 yrs Time to peak = 12.47 hrs
Time interval = 2 min Hyd. volume = 122,582 cuft
Drainage area = 24.500 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 53.20 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(1.500 x 55)+(2.500 x 56)+(20.500 x 48)]/24.500
OSF-2
Q (cfs) Hyd. No. 13--25 Year Q (cfs)
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 13

61
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 14
OSF-3
Hydrograph type = SCS Runoff Peak discharge = 6.563 cfs
Storm frequency = 25 yrs Time to peak = 12.37 hrs
Time interval = 2 min Hyd. volume = 43,106 cuft
Drainage area = 8.600 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 41.60 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(0.600 x 55)+(0.500 x 56)+(7.500 x 48)]/8.600
OSF-3
Q (cfs) Hyd. No. 14--25 Year Q (cfs)
7.00 7.00
6.00 6.00
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 14

62
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 15
OSF-3
Hydrograph type = SCS Runoff Peak discharge = 8.089 cfs
Storm frequency = 25 yrs Time to peak = 12.37 hrs
Time interval = 2 min Hyd. volume = 53,131 cuft
Drainage area = 10.600 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 41.60 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(0.600 x 55)+(0.500 x 56)+(9.500 x 48)]/10.600
OSF-3
Q (cfs) Hyd. No. 15--25 Year Q (cfs)
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 15

63
Hydrograph Summary Report Hydraf low Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 15.46 2 724 45,265 ------ ------ ------ Existing-Phase 1A
2 SCS Runoff 72.20 2 732 301,111 ------ ------ ------ Existing-Phase 1B
3 SCS Runoff 49.96 2 734 227,470 ------ ------ ------ Existing-Phase 1C
4 Combine 109.24 2 732 477,441 2, 3 ------ ------ Existing Areas Combined
5 SCS Runoff 22.95 2 736 115,718 ------ ------ ------ Existing-Phase 2B
6 SCS Runoff 100.88 2 736 470,448 ------ ------ ------ Existing-Phase 2A
7 Reach 80.89 1 737 389,187 6 ------ ------ DP at Basin 1
8 SCS Runoff 5.253 2 734 24,876 ------ ------ ------ Existing-Phase 2131
9 Combine 20.02 2 736 106,274 5,8 ------ ------ DA-4A and B
10 SCS Runoff 77.27 2 762 644,561 ------ ------ ------ Existing-3A(NPI)
11 SCS Runoff 27.11 2 762 226,108 ------ ------ ------ Existing-3B(NPI)
12 SCS Runoff 43.19 2 750 301,005 ------ ------ ------ OSF-1
13 SCS Runoff 31.71 2 748 213,922 ------ ------ ------ OSF-2
14 SCS Runoff 12.99 2 740 75,225 ------ ------ ------ OSF-3
15 SCS Runoff 16.01 2 740 92,720 ------ ------ ------ OSF-3
Construction SWM-R1.gpw Return Period: 100 Year Wednesday, 07/ 10/2024

64
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 1
Existing-Phase 1A
Hydrograph type = SCS Runoff Peak discharge = 15.46 cfs
Storm frequency = 100 yrs Time to peak = 12.07 hrs
Time interval = 2 min Hyd. volume = 45,265 cuft
Drainage area = 4.700 ac Curve number = 52*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 15.40 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.350 x 55)+(2.350 x 48)]/4.700
Existing-Phase 1A
Q (cfs) Hyd. No. 1 -- 100 Year Q (cfs)
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time (hrs)

65
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 2
Existing-Phase 1 B
Hydrograph type = SCS Runoff Peak discharge = 72.20 cfs
Storm frequency = 100 yrs Time to peak = 12.20 hrs
Time interval = 2 min Hyd. volume = 301,111 cuft
Drainage area = 27.100 ac Curve number = 55*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 29.10 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(19.300 x 55)+(8.270 x 56)]/27.100
Existing-Phase 1 B
Q (cfs) Hyd. No. 2-- 100 Year Q (cfs)
80.00 80.00
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 2 Time (hrs)

66
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 3
Existing-Phase 1 C
Hydrograph type = SCS Runoff Peak discharge = 49.96 cfs
Storm frequency = 100 yrs Time to peak = 12.23 hrs
Time interval = 2 min Hyd. volume = 227,470 cuft
Drainage area = 21.000 ac Curve number = 54*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 33.70 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(15.100 x 55)+(3.600 x 48)]/21.000
Existing-Phase 1 C
Q (cfs) Hyd. No. 3-- 100 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 3 Time (hrs)

67
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 4
Existing Areas Combined
Hydrograph type = Combine Peak discharge = 109.24 cfs
Storm frequency = 100 yrs Time to peak = 12.20 hrs
Time interval = 2 min Hyd. volume = 477,441 cuft
Inflow hyds. = 2, 3 Contrib. drain. area = 48.100 ac
Existing Areas Combined
Q (cfs) Hyd. No. 4-- 100 Year Q (cfs)
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 4 Hyd No. 2 Hyd No. 3

68
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 5
Existing-Phase 2B
Hydrograph type = SCS Runoff Peak discharge = 22.95 cfs
Storm frequency = 100 yrs Time to peak = 12.27 hrs
Time interval = 2 min Hyd. volume = 115,718 cuft
Drainage area = 13.510 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 36.00 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(11.300 x 48)+(2.210 x 56)]/13.510
Existing-Phase 2113
Q (cfs) Hyd. No. 5-- 100 Year Q (cfs)
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 5 Time (hrs)

69
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 6
Existing-Phase 2A
Hydrograph type = SCS Runoff Peak discharge = 100.88 cfs
Storm frequency = 100 yrs Time to peak = 12.27 hrs
Time interval = 2 min Hyd. volume = 470,448 cuft
Drainage area = 38.500 ac Curve number = 58*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 36.00 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(19.750 x 48)+(8.780 x 56)+(5.610 x 69)+(2.000 x 98)+(2.360 x 85)]/38.500
Existing-Phase 2A
Q (cfs) Hyd. No. 6-- 100 Year Q (cfs)
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 6 Time (hrs)

70
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 7
DP at Basin 1
Hydrograph type = Reach Peak discharge = 80.89 cfs
Storm frequency = 100 yrs Time to peak = 12.28 hrs
Time interval = 1 min Hyd. volume = 389,187 cuft
Inflow hyd. No. = 6 - Existing-Phase 2A Section type = Trapezoidal
Reach length = 400.0 ft Channel slope = 5.0 %
Manning's n = 0.015 Bottom width = 5.0 ft
Side slope = 4.0:1 Max. depth = 1.0 ft
Rating curve x = 7.592 Rating curve m = 1.135
Ave. velocity = 0.00 ft/s Routing coeff. = 0.9224
Modified Att-Kin routing method used.
DP at Basin 1
Q (cfs) Hyd. No. 7-- 100 Year Q (cfs)
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 1 40.00
20.00 20.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 7 Hyd No. 6

71
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 8
Existing-Phase 2B1
Hydrograph type = SCS Runoff Peak discharge = 5.253 cfs
Storm frequency = 100 yrs Time to peak = 12.23 hrs
Time interval = 2 min Hyd. volume = 24,876 cuft
Drainage area = 2.710 ac Curve number = 50*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 30.60 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.000 x 48)+(0.710 x 56)]/2.710
Existing-Phase 21131
Q (cfs) Hyd. No. 8-- 100 Year Q (cfs)
6.00 6.00
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 8 Time (hrs)

72
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 9
DA-4A and B
Hydrograph type = Combine Peak discharge = 20.02 cfs
Storm frequency = 100 yrs Time to peak = 12.27 hrs
Time interval = 2 min Hyd. volume = 106,274 cuft
Inflow hyds. = 5, 8 Contrib. drain. area = 16.220 ac
DA- A and B
Q (cfs) Hyd. N 9-- 100 Year Q (cfs)
21.00 21.00
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 9 Hyd No. 5 Hyd No. 8

73
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 10
Existing-3A (NPI)
Hydrograph type = SCS Runoff Peak discharge = 77.27 cfs
Storm frequency = 100 yrs Time to peak = 12.70 hrs
Time interval = 2 min Hyd. volume = 644,561 cuft
Drainage area = 63.000 ac Curve number = 53*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 75.70 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(28.000 x 55)+(22.500 x 56)+(51.000 x 48)+(3.500 x 98)]/63.000
Existing-3A (NPI)
Q (cfs) Hyd. No. 10 -- 100 Year Q (cfs)
80.00 80.00
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 10 Time (hrs)

74
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 11
Existing-3B(NPI)
Hydrograph type = SCS Runoff Peak discharge = 27.11 cfs
Storm frequency = 100 yrs Time to peak = 12.70 hrs
Time interval = 2 min Hyd. volume = 226,108 cuft
Drainage area = 22.100 ac Curve number = 53*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 75.70 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(28.000 x 55)+(22.500 x 56)+(51.000 x 48)+(3.500 x 98)]/22.100
Existing-3113(NPI)
Q (cfs) Hyd. No. 11 -- 100 Year Q (cfs)
28.00 28.00
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 11 Time (hrs)

75
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 12
OSF-1
Hydrograph type = SCS Runoff Peak discharge = 43.19 cfs
Storm frequency = 100 yrs Time to peak = 12.50 hrs
Time interval = 2 min Hyd. volume = 301,005 cuft
Drainage area = 35.000 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 56.00 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(2.500 x 55)+(2.400 x 56)+(30.100 x 48)]/35.000
OSF-1
Q (cfs) Hyd. No. 12 -- 100 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 12

76
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 13
OSF-2
Hydrograph type = SCS Runoff Peak discharge = 31.71 cfs
Storm frequency = 100 yrs Time to peak = 12.47 hrs
Time interval = 2 min Hyd. volume = 213,922 cuft
Drainage area = 24.500 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 53.20 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(1.500 x 55)+(2.500 x 56)+(20.500 x 48)]/24.500
OSF-2
Q (cfs) Hyd. No. 13 -- 100 Year Q (cfs)
35.00 35.00
30.00 30.00
25.00 25.00
20.00 20.00
15.00 15.00
10.00 10.00
5.00 5.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 13

77
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 14
OSF-3
Hydrograph type = SCS Runoff Peak discharge = 12.99 cfs
Storm frequency = 100 yrs Time to peak = 12.33 hrs
Time interval = 2 min Hyd. volume = 75,225 cuft
Drainage area = 8.600 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 41.60 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(0.600 x 55)+(0.500 x 56)+(7.500 x 48)]/8.600
OSF-3
Q (cfs) Hyd. No. 14 -- 100 Year Q (cfs)
14.00 14.00
12.00 12.00
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 14

78
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Wednesday,07/10/2024
Hyd. No. 15
OSF-3
Hydrograph type = SCS Runoff Peak discharge = 16.01 cfs
Storm frequency = 100 yrs Time to peak = 12.33 hrs
Time interval = 2 min Hyd. volume = 92,720 cuft
Drainage area = 10.600 ac Curve number = 49*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 41.60 min
Total precip. = 8.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Composite(Area/CN)_[(0.600 x 55)+(0.500 x 56)+(9.500 x 48)]/10.600
OSF-3
Q (cfs) Hyd. No. 15 -- 100 Year Q (cfs)
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 0.00
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Time (hrs)
Hyd No. 15

ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Appendix C:
Proposed (Operational) Sediment Basins
Sizing Calculations
H371132-4000-220-230-0001, Rev. C
©Hatch 2024 All rights reserved,including all rights relating to the use of this document or its contents.

Proposed Sed. Basin (POND-M11)for Post M10-1 Required Sediment Storage Vol. (cu.ft) = 79,400
ft Proposed Grade 845 ac- = 1.82
Proposed Bottom 839 Pond Embankment slo e: 3H:1 V
POND ELEV. AREA VOLUME VOLUME CUMM VOLUME CUMM VOLUME Stage/El. Length ft Width ft
FT. (sq.-ft.) cu.ft.) (ac.-ft.) (ac.-ft.) (cu.ft. 0 125 75
1 131 81
839 9375 0 2 137 87
840 10611 9993.00 0.23 0.23 9,993 3 143 93
841 11919 11265.00 0.26 0.49 21,258 4 149 1 99
842 13299 12609.00 0.29 0.78 33,867 5 155 1 105
843 14751 14025.00 0.32 1.10 47,892 6 161 111
844 16275 15513.00 0.36 1.46 63,405
845 17871 17073.00 0.39 1.85 80,478 ILength ft Width ft Area sft Area(ac)
161 1 111 1 17,871 0.41
Add 8 ft berm for maintenance
@ top of pond (845 ft)
Pond Excavation (cy) 107,226
SEDIMENT BASIN VOLUME REQUIREMENT-SUMMARY Pond Excavation (cf) 3,971
BASIN-ID AREA(AC.) SEDIMENT BASIN SEDIMENT VOL. POND AREA POND FOOTPRINT
ID READ.. CF) (SQ.FT.) (LXWxD FT
M10-1 4.7 POND-M11 17,024 17,871 (161 L, 111 W, 6D)
M10-2 27.6 94,875
POND-M12 70,596 (636 L, 111 W,6D)
M00-2 20.9 76,146
C00-1 13.4 POND-001 48,969 25,536 (106 L, 56W,6D)
C00-2 2.7 POND-CO2 9,837 5,936 (336 L, 76W,6D)
C00-3 38.5 POND-CO3 140,054 58,176 (606 L, 96W,6D)
M80-1 72.8 SRK-POND#1 264,264 71,796 (386 L, 186 W,6D)
M71-1 22.2 POND-M81 80586 18786 (186 L, 101 W,6D)

Proposed Sediment Basin(POND-M11)for Post M10-2&M00-2 Required Sediment Storage Vol.(cu.ft) =1 264,083
ac-ft 6.06
Proposed Grade Elev.= 870
Proposed Bottom El.= 864
Pond Embankment slope:3H:1V
POND ELEVATION AREA VOLUME VOLUME CUMM VOLUME CUMM VOLUME Stage/Elev. Length ft Width ft
(FT.) (sq.-ft.) 0 (cu.ft.) I (ac.-ft.) (ac.-ft.) (cu.ft.) 0 600 75
1 606 81
864 45,000 0 2 612 87
865 49,086 47,043 1.08 1.08 47,043 3 618 93
866 53,244 51,165 1.17 2.25 98,208 4 624 99
867 57,474 55,359 1.27 3.53 153,567 5 630 105
868 61,776 59,625 1.37 4.89 213,192 6 636 111
869 66,150 63,963 1.47 6.36 277,155
870 70,596 68,373 1.57 7.93 345,528 Length(ft) lWidth(ft) Area(sft) Area(ac)
636 1 111 70,596 1 1.62
Add 8 ft berm for maintenance @ top of pond(870 ft)

Proposed Sediment Basin(POND-001)for Post COO-1 Required Sediment Storage Vol. (cu.ft)=1 72,963
Proposed Grade Elev.= 860 ac-ft=1 1.68
Proposed Bottom El.= 854 Pond Embankment slo e:3H:1V
POND ELEV. AREA VOLUME VOLUME CUMM VOLUME CUMM VOLUME Sta a/Elev. Len th ft Width ft
(sq.-ft.) cu.ft.) (ac.-ft.) (ac.-ft.) (cu.ft. 0 300 40
1 306 46
854 12000 0 2 312 52
855 14076 13038.00 0.30 0.30 13,038 3 318 58
856 16224 15150.00 0.35 0.65 28,188 4 324 64
857 18444 17334.00 0.40 1.05 45,522 5 330 70
858 20736 19590.00 0.45 1.49 65,112 6 336 1 76
859 23100 21918.00 0.50 2.00 87,030
860 25536 24318.00 0.56 2.56 111,348 1 Length ft Width ft Area(sft) IArea ac
336 1 76 1 25,536 1 0.59
Add 8 ft berm for maintenance @ top of pond(845 ft)

Proposed Sediment Basin(POND-M81)for Post M71-1 Required Sediment Storage Vol.(cu.ft) =1 264,264
(ac-ft)l 6.07
Proposed Grade Elev.= 960
Proposed Bottom EI.= 954
Pond Embankment slope:3H:1V
POND ELEVATION AREA VOLUME VOLUME CUMM VOLUME CUMM VOLUME Stage/Elev. ILength(ft) Width(ft)
FT. (sq.-ft-) cu.ft. ac.-ft.) (ac.-ft.) (cu.ft. 0 350 150
1 356 156
960 52,500 0 2 362 162
961 55,536 54,018 1.24 1.24 54,018 3 368 168
962 58,644 57,090 1.31 2.55 111,108 4 374 174
963 61,824 60,234 1.38 3.93 171,342 5 1 380 180
964 65,076 63,450 1.46 5.39 234,792 6 386 186
965 68,400 66,738 1.53 6.92 301,530
966 71,796 70,098 1.61 8.53 371,628 Length(ft) lWidth(ft) Area(sft) jArea(ac)
386 1 186 1 71,796 1 1.65
Add 8 ft berm for maintenance @ top of pond(870 ft)

Proposed Sediment Basin OSF-1 Required Sediment Storage Vol.(cu.ft) =1 62,799
Proposed Grade Elev.= 925(Estimated) (ac-ft)= 1.44
Proposed Bottom El.= 914 Pond Embankment slope:3H:1V
POND ELEV. AREA VOLUME VOLUME CUMM VOLUME CUMM VOLUME Sta a/EI. Len th ft Width ft
(FT.) (sq.-ft.) (cu.ft.) (ac.-ft.) (ac.-ft.) (cu.ft.) 0 250 75
1 256 81
914 18750 0 2 262 87
915 20736 19743.00 0.45 0.45 19,743 3 268 93
916 22794 21765.00 0.50 0.95 41,508 4 274 99
917 24924 23859.00 0.55 1.50 65,367 5 280 105
918 27126 26025.00 0.60 2.10 91,392 6 286 111
919 29400 28263.00 0.65 2.75 119,655
920 31746 30573.00 0.70 3.45 150,228 ILength(ft)lWidth(ft) jArea(sft) jArea(ac)
286 111 31,746 0.73
Total Disturbed Area(LOD)=24.5 acres
19"OUTLET PIPE(Inv._) 914
WSE POND DEPTH
(ft.) b ORIFICE FLOW WEIR FLOW
(cfs) (cfs)
914
914.5 0.5
915 1 2.00 2.35
915.5 1.5 2.00 13.99 6.66
916 2 2.00 19.78 12.24
916.5 2.5 2.00 24.23 18.84
917 3 2.00 27.98 26.33
917.5 3.5 2.00 31.28 34.61
918 4 2.00 34.26 43.61
918.5 4.5 2.00 37.01 53.28
919 5 2.00 39.57 63.58
919.5 5.5 2.00 41.97 74.46
920 6 2.00 44.24 85.90

Proposed Sediment Basin OSF-2 Required Sediment Storage Vol.(cu.ft) =1 44,122
Proposed Grade Elev.= 925(Estimated) (ac-ft)= 1.01
Proposed Bottom El.= 914 Pond Embankment slope: 3H:1V
POND ELEV. AREA VOLUME VOLUME CUMM VOLUME CUMM VOLUME Stage/El. Length ft Width ft
FT. sq.-ft. cu.ft.) (ac.-ft.) (ac.-ft.) (cu.ft. 0 175 80
1 181 86
914 14000 0 2 187 92
915 15566 14783.00 0.34 0.34 14,783 3 193 98
916 17204 16385.00 0.38 0.72 31,168 4 199 104
917 18914 18059.00 0.41 1.13 49,227 5 205 110
918 20696 19805.00 0.45 1.58 69,032 6 211 116
919 22550 21623.00 0.50 2.08 90,655
920 24476 23513.00 0.54 2.62 114,168 1 Length ft Width ft Area sft Area ac
211 116 24,476 0.56
Total Disturbed Area(LOD)=34.9 acres
19"OUTLET PIPE(Inv. _) 914
WSE POND DEPTH
(ft.) b ORIFICE FLOW WEIR FLOW
(cfs) (cfs)
914
914.5 0.5
915 1 2.00 2.35
915.5 1.5 2.00 13.99 6.66
916 2 2.00 19.78 12.24
916.5 2.5 2.00 24.23 18.84
917 3 2.00 27.98 26.33
917.5 3.5 2.00 31.28 34.61
918 4 2.00 34.26 43.61
918.5 4.5 2.00 37.01 53.28
919 5 2.00 39.57 63.58
919.5 5.5 2.00 41.97 74.46
920 6 2.00 44.24 85.90

Proposed Sediment Basin OSF-3 Required Sediment Storage Vol.(cu.ft) =1 44,122
Proposed Grade Elev.= 900(Estimated) (ac-ft)= 1.01
Proposed Bottom El.= 875 Pond Embankment slope:31H:1V
POND ELEV. AREA VOLUME VOLUME CUMM VOLUME CUMM VOLUME Sta a/Elev.Len th ft Width ft
(FT.) (sq.-ft.) (cu.ft.) (ac.-ft.) (ac.-ft.) (cu.ft.) 0 200 70
1 206 76
875 14000 0 2 212 82
876 15656 14828.00 0.34 0.34 14,828 3 218 88
877 17384 16520.00 0.38 0.72 31,348 4 224 94
878 19184 18284.00 0.42 1.14 49,632 5 230 100
879 21056 20120.00 0.46 1.60 69,752 6 236 106
880 23000 22028.00 0.51 2.11 91,780
881 25016 24008.00 0.55 2.66 115,788 IlLength(ft)lWidth(ft) jArea(sft) jArea(ac)
236 1 106 1 25,016 1 0.57
Total Disturbed Area(LOD)=8.6 acres

Proposed Detention Basin Duke Pad(500 ftx500 ft) Required Sediment Storage Vol.(cu.ft) = 66,892
Proposed Grade Elev.= 830(Estimated) ac-ft= 1.54
Proposed Bottom El.= 825 Pond Embankment slope:3H:1V
POND ELEV. AREA VOLUME VOLUME CUMM VOLUME CUMM VOLUME Sta a/Elev Length(ft)Width ft
FT. sq.-ft. cu.ft.) (ac.-ft.) (ac.-ft.) (cu.ft. 0 125 75
1 131 81
825 9375 0 2 137 87
826 10611 9993.00 0.23 0.23 9,993 3 143 93
827 11919 11265.00 0.26 0.49 21,258 4 149 99
828 13299 12609.00 0.29 0.78 33,867 5 155 105
829 14751 14025.00 0.32 1.10 47,892 6 161 111
830 16275 15513.00 0.36 1.46 63,405
831 17871 17073.00 0.39 1.85 80.478 ILength ft Width ft Area sft Area ac
161 1 111 17,871 1 0.41
Add 8 ft berm for maintenance
on the top of pond @831 ft
Total Disturbed Area(LOD)=12.9 acres
Disturbed Area excluding accessroad and Laydown area=9.28 acres

ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Appendix D:
Proposed Sewer Sizing Calculations
H371132-4000-220-230-0001, Rev. C
©Hatch 2024 All rights reserved,including all rights relating to the use of this document or its contents.

Albemarle,Kings Mountain Drainage Study,NC
Pipe Flow Computation,Manning's Equation
Pipe Diameter 18 in
1.50 ft
Pipe Radius 9 in
0.75 ft/ft
Manning's"n" Reinforced Concrete Pipe 0.013
Pipe Slope 0.02 ft/ft
2.00%
Depth of Flow Wetted Hydraulic Top
Water theta Radius R2 Area Perimeter Radius Width Flow Velocity
h,in h,ft radians ft ft2 (R-h) (R-h/RCos-1 R-h/R 2Rh h2 2Rh-h2 2Rh-h2 A.5 Sq ft ft ft ft Cfs 9pm gpd fps
0.00 0.00 0.0000 0.7500 0.5625 0.7500 1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00 0.00 0.00 0.00 0 0 0.00
1.00 0.08 0.9518 0.7500 0.5625 0.6667 0.8889 0.4759 0.1250 0.0069 0.1181 0.3436 0.0386 0.71 0.05 0.69 0.09 40 57,722 2.31
3.00 0.25 1.6821 0.7500 0.5625 0.5000 0.6667 0.8411 0.3750 0.0625 0.3125 0.5590 0.1936 1.26 0.15 1.12 0.90 403 579,703 4.63
6.00 0.50 2.4619 0.7500 0.5625 0.2500 0.3333 1.2310 0.7500 0.2500 0.5000 0.7071 0.5156 1.85 0.28 1.41 3.56 1,598 2,301,569 6.91
8.00 0.67 1 2.91891 0.75001 0.56251 0.08331 0.1111 1 1.4595 1.0000 0.4444 0.5556 0.7454 0.7588 2.19 0.35 1.49 6.05 2,717 3,911,943 7.98
9.00 0.75 3.1416 0.7500 0.56251 0.00001 0.0000 1 1.5708 1.1250 0.5625 0.5625 0.7500 0.8836 2.36 0.38 1.50 7.43 3,334 4,800,307 8.41
12.00 1.00 3.8213 0.7500 0.5625 -0.2500 -0.3333 1.9106 1.5000 1.0000 0.5000 0.7071 1.2515 2.87 0.44 1.41 11.64 5,226 7,525,743 9.30
15.00 1.25 4.6010 0.7500 0.5625 -0.5000 -0.6667 2.3005 1.8750 1.5625 0.3125 0.5590 1.5736 3.45 0.46 1.12 15.07 6,763 9,739,340 9.58
18.00 1.50 6.2832 0.7500 0.5625 -0.7500 -1.0000 1 3.1416 2.2500 2.2500 0.0000 0.0000 1.7671 4.71 0.38 0.00 14.86 6,667 9,600,615 8.41

Albemarle,Kings Mountain Drainage Study,NC
Pipe Flow Computation,Manning's Equation
Pipe Diameter 24 in
2.00 ft
Pipe Radius 12 in
1.00 ft/ft
Manning's"n" Reinforced Concrete Pipe 0.013
Pipe Slope 0.02 ft/ft
2.00%
Depth of Flow Wetted Hydraulic Top
Water theta Radius R2 Area Perimeter Radius Width Flow Velocity
h,in h,ft radians ft ft2 (R-h) (R-h/RCos-1 R-h/R 2Rh h2 2Rh-h2 2Rh-h2 A.5 Sq ft ft ft ft Cfs gpm gpd fps
0.00 0.00 0.0000 1.0000 1.0000 1.0000 1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00 0.00 0.00 0.00 0 0 0.00
1.00 0.08 0.8223 1.0000 1.0000 0.9167 0.9167 0.4111 0.1667 0.0069 0.1597 0.3997 0.0448 0.82 0.05 0.80 0.10 47 67,239 2.32
3.00 0.25 1.4455 1.0000 1.0000 0.7500 0.7500 0.7227 0.5000 0.0625 0.4375 0.6614 0.2267 1.45 0.16 1.32 1.07 478 688,565 4.70
6.00 0.50 2.0944 1.0000 1.0000 0.5000 0.5000 1.0472 1.0000 0.2500 0.7500 0.8660 0.6142 2.09 0.29 1.73 4.38 1,967 2,832,252 7.14
8.00 0.67 2.4619 1.0000 1.0000 0.33331 0.3333 1.2310 1.3333 0.44441 0.8889 0.9428 0.9167 2.46 0.37 1.89 7.67 3,442 4,956,715 8.37
9.00 0.75 2.6362 1.0000 1.0000 0.2500 0.2500 1.3181 1.5000 0.5625 0.9375 0.9682 1.0761 2.64 0.41 1.94 9.57 4,296 6,185,962 8.90
12.00 1.00 3.1416 1.0000 1.0000 0.0000 0.0000 1.5708 2.0000 1.0000 1.0000 1.0000 1.5708 3.14 0.50 2.00 16.00 7,179 10,338,059 10.18
15.00 1.25 3.6470 1.0000 1.0000 -0.2500 -0.2500 1.8235 2.5000 1.5625 0.9375 0.9682 2.0655 3.65 0.57 1.94 22.86 10,258 14,772,058 11.07
18.00 1.50 4.1888 1.0000 1.0000 -0.5000 -0.5000 2.0944 3.0000 2.2500 0.7500 0.8660 2.5274 4.19 0.60 1.73 29.17 13,093 18,854,091 11.54
21.00 1.75 4.8377 1.0000 1.0000 -0.7500 -0.7500 2.4189 3.5000 3.0625 0.4375 0.6614 2.9149 4.84 0.60 1.32 33.62 15,087 21,725,047 11.53
24.00 2.00 6.2832 1.0000 1.0000 -1.0000 -1.0000 3.1416 1 4.0000 4.0000 0.0000 0.0000 3.1416 6.28 0.50 0.00 31.99 14,358 20,676,118 10.18

Albemarle,Kings Mountain Drainage Study,NC
Pipe Flow Computation,Manning's Equation
Pipe Diameter 30 in
2.50 ft
Pipe Radius 15 in
1.25 ft/ft
Manning's"n" Reinforced Concrete Pipe 0.013
Pipe Slope 0.02 ft/ft
2.00%
Depth of Flow Wetted Hydraulic Top
Water theta Radius R2 Area Perimeter Radius Width Flow Velocity
h,in h,ft radians ft ft2 (R-h) (R-h/RCos-1 R-h/R 2Rh h2 2Rh-h2 2Rh-h2 A.5 Sq ft ft ft ft Cfs gpm gpd fps
0.00 0.00 0.0000 1.2500 1.5625 1.2500 1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00 0.00 0.00 0.00 0 0 0.00
1.00 0.08 0.7344 1.2500 1.5625 1.1667 0.9333 0.3672 0.2083 0.0069 0.2014 0.4488 0.0502 0.92 0.05 0.90 0.12 52 75,570 2.33
3.00 0.25 1.2870 1.2500 1.5625 1.0000 0.8000 0.6435 0.6250 0.0625 0.5625 0.7500 0.2555 1.61 0.16 1.50 1.21 544 782,674 4.74
6.00 0.50 1.8546 1.2500 1.5625 0.7500 0.6000 0.9273 1.2500 0.2500 1.0000 1.0000 0.6989 2.32 0.30 2.00 5.08 2,280 3,282,899 7.27
8.00 0.67 2.1706 1.2500 1.5625 0.5833 0.4667 1.0853 1.66671 0.44441 1.2222 1.1055 1.0508 2.71 0.39 2.21 9.03 4,051 5,833,352 8.59
9.00 0.75 2.3186 1.2500 1.5625 0.5000 0.4000 1.1593 1.8750 0.5625 1.3125 1.1456 1.2386 2.90 0.43 2.29 11.36 5,098 7,341,378 9.17
12.00 1.00 2.7389 1.2500 1.5625 0.2500 0.2000 1.3694 2.5000 1.0000 1.5000 1.2247 1.8336 3.42 0.54 2.45 19.55 8,773 12,633,097 10.66
15.00 1.25 3.1416 1.2500 1.5625 0.0000 0.0000 1.5708 3.1250 1.5625 1.5625 1.2506 2.4544 3.93 0.63 2.50 29.00 13,017 18,744,148 11.82
18.00 1.50 3.5443 1.2500 1.5625 -0.2500 -0.2000 1.7722 3.7500 2.2500 1.5000 1.2247 3.0752 4.43 0.69 2.45 38.97 17,490 25,186,145 12.67
21.00 1.75 3.9646 1.2500 1.5625 -0.5000 -0.4000 1.9823 4.3750 3.0625 1.3125 1.1456 3.6702 4.96 0.74 2.29 48.57 21,796 31,386,614 13.23
24.00 2.00 4.4286 1.2500 1.5625 -0.7500 -0.6000 2.2143 5.0000 4.0000 1.0000 1.0000 4.2098 5.54 0.76 2.00 56.70 25,447 36,643,568 13.47
27.00 2.25 4.9962 1.2500 1.5625 -1.0000 -0.8000 2.4981 5.6250 5.0625 0.5625 0.7500 4.6533 6.25 0.75 1.50 61.82 27,746 39,954,927 13.29
30.00 2.50 6.2832 1.2500 1.5625 -1.2500 -1.0000 3.1416 6.2500 6.2500 0.0000 0.0000 4.9087 7.85 0.63 0.00 58.01 26,034 37,488,296 11.82

Albemarle,Kings Mountain Drainage Study,NC
Pipe Flow Computation,Manning's Equation
Pipe Diameter 36 in
3.00 ft
Pipe Radius 18 in
1.50 ft/ft
Manning's"n" Reinforced Concrete Pipe 0.013
Pipe Slope 0.0125 ft/ft
1.25%
Depth of Flow Wetted Hydraulic Top
Water theta Radius R2 Area Perimeter Radius Width Flow Velocity
h,in h,ft radians ft ft2 (R-h) (R-h/RCos-1 R-h/R 2Rh h2 2Rh-h2 2Rh-h2 A.5 Sq ft ft ft ft Cfs qpm gpd fps
0.00 0.00 0.0000 1.5000 2.2500 1.5000 1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00 0.00 0.00 0.00 0 0 0.00
1.00 0.08 0.6698 1.5000 2.2500 1.4167 0.9444 0.3349 0.2500 0.0069 0.2431 0.4930 0.0551 1.00 0.05 0.99 0.10 46 65,672 1.84
3.00 0.25 1.1714 1.5000 2.2500 1.2500 0.8333 0.5857 0.7500 0.0625 0.6875 0.8292 0.2813 1.76 0.16 1.66 1.06 476 685,214 3.77
6.00 0.50 1.6821 1.5000 2.2500 1.0000 0.6667 0.8411 1.5000 0.2500 1.2500 1.1180 0.7744 2.52 0.31 2.24 4.50 2,021 2,909,993 5.81
8.00 0.67 1.9635 1.5000 2.2500 0.83331 0.5556 0.9818 2.0000 0.44441 1.5556 1.2472 1.1696 2.95 0.40 2.49 8.08 3,624 5,219,187 6.90
9.00 0.75 2.0944 1.5000 2.2500 0.7500 0.5000 1.0472 2.2500 0.5625 1.6875 1.2990 1.3819 3.14 0.44 2.60 10.21 4,584 6,601,591 7.39
12.00 1.00 2.4619 1.5000 2.2500 0.5000 0.3333 1.2310 3.0000 1.0000 2.0000 1.4142 2.0626 3.69 0.56 2.83 17.88 8,023 11,553,422 8.67
15.00 1.25 2.8067 1.5000 2.2500 0.2500 0.1667 1.4033 3.7500 1.5625 2.1875 1.4790 2.7878 4.21 0.66 2.96 27.07 12,148 17,492,496 9.71
18.00 1.50 3.1416 1.5000 2.2500 0.0000 0.0000 1.5708 4.5000 2.2500 2.2500 1.5000 3.5343 4.71 0.75 3.00 37.29 16,734 24,096,597 10.55
21.00 1.75 3.4765 1.5000 2.2500 -0.2500 -0.1667 1.7382 5.2500 3.0625 2.1875 1.4790 4.2808 5.21 0.82 2.96 47.96 21,526 30,997,985 11.20
24.00 2.00 3.8213 1.5000 2.2500 -0.5000 -0.3333 1.9106 6.0000 4.0000 2.0000 1.4142 5.0060 5.73 0.87 2.83 58.45 26,235 37,777,747 11.68
27.00 2.25 4.1888 1.5000 2.2500 -0.7500 -0.5000 2.0944 6.7500 5.0625 1.6875 1.2990 5.6867 6.28 0.91 2.60 68.00 30,518 43,946,298 11.96
30.00 2.50 4.6010 1.5000 2.2500 -1.0000 -0.6667 2.3005 7.5000 6.2500 1.2500 1.1180 6.2942 6.90 0.91 2.24 75.65 33,951 48,889,566 12.02
33.00 2.75 5.1118 1.5000 2.2500 -1.2500 -0.8333 2.5559 8.2500 7.5625 0.6875 0.8292 6.7872 7.67 0.89 1.66 79.97 35,889 51,680,083 1 11.78
36.00 1 3.00 1 6.2832 1.50001 2.2500 -1.5000 -1.0000 1 3.1416 9.0000 1 9.00001 0.0000 0.0000 7.0686 1 9.42 0.75 0.00 1 74.57 33,467 48,193,193 1 10.55

Albemarle,Kings Mountain Drainage Study,INC
Pipe Flow Computation,Manning's Equation
Pipe Diameter 42 in
3.50 ft
Pipe Radius 21 in
1.75 ft/ft
Manning's"n" Reinforced Concrete Pipe 0.013
Pipe Slope 0.01 ft/ft
1.00%
Depth of Flow Wetted Hydraulic Top
Water theta Radius R2 Area Perimeter Radius Width Flow Velocity
h,in F h,ft radians ft ft2 (R-h) (R-h/R os-1 R-h/R 2Rh h2 2Rh-h2 2Rh-h2^.5 Sq ft ft ft ft cfs gpm gpd fps
0.00 0.00 0.0000 1.7500 3.0625 1.7500 1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00 0.00 0.00 0.00 0 0 0.00
1.00 0.08 0.6197 1.7500 3.0625 1.6667 0.9524 0.3098 0.2917 0.0069 0.2847 0.5336 0.0596 1.08 0.05 1.07 0.10 44 63,602 1.65
3.00 0.25 1.0822 1.7500 3.0625 1.5000 0.8571 0.5411 0.8750 0.0625 0.8125 0.9014 0.3050 1.89 0.16 1.80 1.03 463 667,080 3.38
6.00 0.50 1.5504 1.7500 3.0625 1.2500 0.7143 0.7752 1.7500 0.2500 1.5000 1.2247 0.8431 2.71 0.31 2.45 4.42 1,984 2,857,389 5.24
8.00 0.67 1 1.8065 1.75001 3.0625 1.08331 0.6190 0.9033 1 2.3333 0.4444 1.8889 1 1.3744 1.2774 1 3.16 0.40 2.75 1 7.98 3,581 5,157,284 6.25
9.00 0.75 1.9251 1.7500 3.0625 1.0000 0.5714 0.9626 2.6250 0.5625 2.0625 1.4361 1.5117 3.37 0.45 2.87 10.13 4,545 6,545,234 6.70
12.00 1.00 2.2558 1.7500 3.0625 0.7500 0.4286 1.1279 3.5000 1.0000 2.5000 1.5811 2.2683 3.95 0.57 3.16 17.92 8043 11,581582 7.90
15.00 1.25 2.5621 1.7500 3.0625 0.5000 0.2857 1.2810 4.3750 1.5625 2.8125 1.6771 3.0847 4.48 0.69 3.35 27.48 12,333 17,758,978 8.91
18.00 1.50 2.8549 1.7500 3.0625 0.2500 0.1429 1.4274 5.2500 2.2500 3.0000 1.7321 3.9385 5.00 0.79 3.46 38.42 17,243, 24,829 360 9.75
21.00 1.75 3.1416 1.7500 3.0625 0.0000 0.0000 1.5708 6.1250 3.0625 3.0625 1.7500 4.8106 5.50 0.88 3.50 50.30 22,5771 32,510,637 10.46
24.00 2.00 3.4283 1.7500 3.0625 -0.2500 -0.1429 1.7141 7.0000 4.0000 3.0000 1.7321 5.6826 6.00 0.95 3.46 62.65 28,1161 40,487 688 11.02
27.00 2.25 3.7211 1.7500 3.0625 -0.5000 -0.2857 1.8605 7.8750 5.0625 2.8125 1.6771 6.5365 6.51 1.00 3.35 74.90 33,617 48,408,524 11.46
30.00 2.50 4.0274 1.7500 3.0625 -0.7500 -0.4286 2.0137 8.7500 6.2500 2.5000 1.5811 7.3528 7.05 1.04 3.16 86.46 38,801 55,873 476 11.76
33.00 2.75 4.3581 1.7500 3.0625 -1.0000 -0.5714 2.1790 9.6250 7.5625 2.0625 1.4361 8.1095 7.63 1.06 2.87 96.57 43,340 62,410,064 11.91
36.00 3.00 4.7328 1.7500 3.0625 -1.2500 -0.7143 2.3664 10.5000 9.0000 1.5000 1.2247 8.7780 8.28 1.06 2.45 104.30 46,812 67,408 567 11.88
39.00 3.25 5.2010 1.7500 3.0625 -1.5000 -0.8571 2.6005 11.3750 10.5625 0.8125 0.9014 9.3161 9.10 1.02 1.80 108.16 48,540 69,897,971 11.61
42.00 3.50 6.2832 1.7500 3.0625 -1.7500 -1.0000 3.1416 12.2500 12.2500 0.0000 0.0000 9.6211 11.00 0.88 0.00 100.61 45154 65,091273 10.46

Albemarle,Kings Mountain Drainage Study,NC
Pipe Flow Computation,Manning's Equation
Pipe Diameter 54 in
4.50 ft
Pipe Radius 27 in
2.25 ft/ft
Manning's"n" Reinforced Concrete Pipe 0.013
Pipe Slope 0.0125 ft/ft
1.25%
Depth of Flow Wetted Hydraulic Top
Water theta Radius R2 Area Perimeter Radius Width Flow Velocity
h,in h,ft radians ft ft2 R-h R-h/R os-1 R-h/R 2Rh h2 2Rh-h2 2Rh-h2^.5 s ft ft ft ft m d fps
0.00 0.00 0.0000 2.2500 5.0625 2.2500 1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00 0.00 0.00 0.00 0 0 0.00
1.00 0.08 0.5460 2.2500 5.0625 2.1667 0.9630 0.2730 0.3750 0.0069 0.3681 0.6067 0.0677 1.23 0.06 1.21 0.13 56 80,896 1.85
3.00 0.25 0.9518 2.2500 5.0625 2.0000 0.8889 0.4759 1.1250 0.0625 1.0625 1.0308 0.3476 2.14 0.16 2.06 1.32 593 854,292 3.80
6.00 0.50 1.3593 2.2500 5.0625 1.7500 0.7778 0.6797 2.2500 0.2500 2.0000 1.4142 0.9660 3.06 0.32 2.83 5.73 2,570 3,700,101 5.93
8.00 0.67 1 1.5804 2.25001 5.0625 1.58331 0.7037 1 0.7902 3.0000 0.4444 2.5556 1 1.5986 1.4693 3.56 0.41 3.20 10.42 4,675 6,731,930 7.09
9.00 0.75 1.6821 2.2500 5.0625 1.5000 0.6667 0.8411 3.3750 0.5625 2.8125 1.6771 1.7423 3.78 0.46 3.35 13.28 5,958 8,579,633 7.62
12.00 1.00 1.9635 2.2500 5.0625 1.2500 0.5556 0.9818 4.5000 1.0000 3.5000 1.8708 2.6317 4.42 0.60 3.74 23.81 10,686 15,387 907 9.05
15.00 1.25 2.2205 2.2500 5.0625 1.0000 0.4444 1.1102 5.6250 1.5625 4.0625 2.0156 3.6050 5.00 0.72 4.03 37.06 16,635 23,953,845 10.28
18.00 1.50 2.4619 2.2500 5.0625 0.7500 0.3333 1.2310 6.7500 2.2500 4.5000 2.1213 4.6407 5.54 0.84 4.24 52.71 23,655 34,063 347 11.36
21.00 1.75 2.6934 2.2500 5.0625 0.5000 0.2222 1.3467 7.8750 3.0625 4.8125 2.1937 5.7208 6.06 0.94 4.39 70.36 31,576 45,469,409 12.30
24.00 2.00 2.9189 2.2500 5.0625 0.2500 0.1111 1.4595 9.0000 4.0000 5.0000 2.2361 6.8295 6.57 1.04 4.47 89.59 40,206 57,896 972 13.12
27.00 2.25 3.1416 2.2500 5.0625 0.0000 0.0000 1.5708 10.1250 5.0625 5.0625 2.2500 7.9522 7.07 1.13 4.50 109.93 49,337 71,044,817 13.82
30.00 2.50 3.3643 2.2500 5.0625 -0.2500 -0.1111 1.6821 11.2500 6.2500 5.0000 2.2361 9.0748 7.57 1.20 4.47 130.88 58,740 84,585 237 14.42
33.00 2.75 3.5898 2.2500 5.0625 -0.5000 -0.2222 1.7949 12.3750 7.5625 4.8125 2.1937 10.1835 8.08 1.26 4.39 151.89 68,168 98,161,379 14.92
36.00 3.00 3.8213 2.2500 5.0625 -0.7500 -0.3333 1.9106 13.5000 9.0000 4.5000 2.1213 11.2636 8.60 1.31 4.24 1 172.34 77,348 111 381,419 15.30
39.00 3.25 4.0627 2.2500 5.0625 -1.0000 -0.4444 2.0314 14.6250 10.5625 4.0625 2.0156 12.2993 9.14 1.35 4.03 191.57 85,977 123,807,453 15.58
42.00 3.50 4.3197 2.2500 5.0625 -1.2500 -0.5556 2.1598 15.7500 12.2500 3.5000 1.8708 13.2727 9.72 1.37 3.74 208.79 93,704 134 934,026 15.73
45.00 3.75 4.6010 2.2500 5.0625 -1.5000 -0.6667 2.3005 16.8750 14.0625 2.8125 1.6771 14.1620 10.35 1.37 3.35 223.04 100,099 144,142,772 15.75
48.00 4.00 4.9238 2.2500 5.0625 -1.7500 -0.7778 2.4619 18.0000 16.0000 2.0000 1.4142 14.9383 11.08 1.35 2.83 233.01 104,575 150 588,602 15.60
51.00 4.25 5.3314 2.2500 5.0625 -2.0000 -0.8889 2.6657 19.1250 18.0625 1.0625 1.0308 15.5567 12.00 1.30 2.06 236.43 106,112 152,800,634 15.20
54.00 4.50 6.2832 2.2500 5.0625 -2.2500 -1.0000 1 3.1416 1 20.2500 1 20.2500 0.0000 0.0000 15.9043 14.14 1.13 0.00 219.86 1 98,673 142 089,634 13.82

Albemarle,Kings Mountain Drainage Study,NC
Pipe Flow Computation,Manning's Equation
Pipe Diameter 60 in
5.00 ft
Pipe Radius 30 in
2.50 ft/ft
Manning's"n" Reinforced Concrete Pipe 0.013
Pipe Slope 0.0125 ft/ft
1.25%
Depth of Flow Wetted Hydraulic Top
Water theta Radius R2 Area Perimeter Radius Width Flow Velocity
h,in h,ft radians ft ft2 R-h R-h/R os-1 R-h/R 2Rh h2 2Rh-h2 2Rh-h2^.5 s ft ft ft ft m d fps
0.00 0.00 0.0000 2.5000 6.2500 2.5000 1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00 0.00 0.00 0.00 0 0 0.00
1.00 0.08 0.5178 2.5000 6.2500 2.4167 0.9667 0.2589 0.4167 0.0069 0.4097 0.6401 0.0714 1.29 0.06 1.28 0.13 59 85,369 1.85
3.00 0.25 0.9021 2.5000 6.2500 2.2500 0.9000 0.4510 1.2500 0.0625 1.1875 1.0897 0.3670 2.26 0.16 2.18 1.40 628 903,678 3.81
6.00 0.50 1.2870 2.5000 6.2500 2.0000 0.8000 0.6435 2.5000 0.2500 2.2500 1.5000 1.0219 3.22 0.32 3.00 6.08 2,728 3,928,868 5.95
8.00 0.67 1.4952 2.5000 6.2500 1.8333 0.7333 0.7476 3.3333 0.4444 2.8889 1.6997 1.5563 3.74 0.42 3.40 11.09 4,977 7167,439 7.13
9.00 0.75 1.5908 2.5000 6.2500 1.7500 0.7000 0.7954 3.7500 0.5625 3.1875 1.7854 1.8469 3.98 0.46 3.57 14.15 6,352 9,147,495 7.66
12.00 1.00 1.8546 2.5000 6.2500 1.5000 0.6000 0.9273 5.0000 1.0000 4.0000 2.0000 2.7956 4.64 0.60 4.00 25.50 11,444 1 16,479 508 9.12
15.00 1.25 2.0944 2.5000 6.2500 1.2500 0.5000 1.0472 6.2500 1.5625 4.6875 2.1651 3.8387 5.24 0.73 4.33 39.89 17,901 25,777,764 10.39
18.00 1.50 2.3186 2.5000 6.2500 1.0000 0.4000 1.1593 7.5000 2.2500 5.2500 2.2913 4.9542 5.80 0.85 4.58 57.02 25,592 36,852 269 11.51
21.00 1.75 2.5322 2.5000 6.2500 0.7500 0.3000 1.2661 8.7500 3.0625 5.6875 2.3848 6.1245 6.33 0.97 4.77 76.56 34,362 49,481,034 12.50
24.00 2.00 2.7389 2.5000 6.2500 0.5000 0.2000 1.3694 10.0000 4.0000 6.0000 2.4495 7.3342 6.85 1.07 4.90 98.13 44,039 63,415 658 13.38
27.00 2.25 2.9413 2.5000 6.2500 0.2500 0.1000 1.4706 11.2500 5.0625 6.1875 2.4875 8.5696 7.35 1.17 4.97 121.29 54,433 78,384,147 14.15
30.00 2.50 3.1416 2.5000 6.2500 0.0000 0.0000 1.5708 12.5000 6.2500 6.2500 2.5000 9.8175 7.85 1.25 5.00 145.59 65,342 94,091 929 14.83
33.00 2.75 3.3419 2.5000 6.2500 -0.2500 -0.1000 1.6710 13.7500 7.5625 6.1875 2.4875 11.0654 8.35 1.32 4.97 170.55 76,543 110,221,342 15.41
36.00 3.00 1 3.5443 2.50001 6.2500 -0.5000 -0.2000 1.7722 15.0000 9.0000 6.0000 2.4495 12.3007 1 8.86 1.39 4.90 1 195.63 87,798 1126,429,482 15.90
39.00 3.25 3.7510 2.5000 6.2500 -0.7500 -0.3000 1.8755 16.2500 10.5625 5.6875 2.3848 13.5104 9.38 1.44 4.77 220.25 98,850 142,343,856 16.30
42.00 3.50 3.9646 2.5000 6.2500 -1.0000 -0.4000 1.9823 17.5000 12.2500 5.2500 2.2913 14.6807 9.91 1.48 4.58 243.79 109,413 157 554,613 16.61
45.00 3.75 4.1888 2.5000 6.2500 -1.2500 -0.5000 2.0944 18.7500 14.0625 4.6875 2.1651 15.7963 10.47 1.51 4.33 265.52 119,167 171,600,662 16.81
48.00 4.00 4.4286 2.5000 6.2500 -1.5000 -0.6000 2.2143 20.0000 16.0000 4.0000 2.0000 16.8394 11.07 1.52 4.00 284.62 127,739 183 943,490 16.90
51.00 4.25 4.6924 2.5000 6.2500 -1.7500 -0.7000 2.3462 21.2500 18.0625 3.1875 1.7854 17.7881 11.73 1.52 3.57 300.05 134,661 193,912,255 16.87
54.00 4.50 4.9962 2.5000 6.2500 -2.0000 -0.8000 2.4981 22.5000 20.2500 2.2500 1.5000 18.6131 12.49 1.49 3.00 310.34 139,282 200 565,857 16.67
57.00 4.75 5.3811 2.5000 6.2500 -2.2500 -0.9000 2.6906 23.7500 22.5625 1.1875 1.0897 19.2679 13.45 1.43 2.18 312.88 140,421 202,206,294 16.24
60.00 5.00 1 6.2832 2.5000 6.2500 -2.5000 -1.0000 3.1416 1 25.0000 1 25.0000 0.0000 0.0000 19.6350 15.71 1.25 0.00 1 291.18 1 130,683 188183,859 14.83

Albemarle,Kings Mountain Drainage Study,NC
Pipe Flow Computation,Manning's Equation
Pipe Diameter 72 in
6.00 ft
Pipe Radius 36 in
3.00 ft/ft
Manning's"n" Reinforced Concrete Pipe 0.013
Pipe Slope 0.01 ft/ft
1.00%
Depth of Flow Wetted Hydraulic Top
Water theta Radius R2 Area Perimeter Radius Width Flow Velocity
h,in h,ft radians ft ft2 R-h R-h/R os-1 R-h/R 2Rh h2 2Rh-h2 2Rh-h2^.5 s ft ft ft ft m d fps
0.00 0.00 0.0000 3.0000 9.0000 3.0000 1.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00 0.00 0.00 0.00 0 0 0.00
1.00 0.08 0.4725 3.0000 9.0000 2.9167 0.9722 0.2363 0.5000 0.0069 0.4931 0.7022 0.0782 1.42 0.06 1.40 0.13 58 83,788 1.66
3.00 0.25 0.8223 3.0000 9.0000 2.7500 0.9167 0.4111 1.5000 0.0625 1.4375 1.1990 0.4031 2.47 0.16 2.40 1.38 618 890,085 3.42
6.00 0.50 1.1714 3.0000 9.0000 2.5000 0.8333 0.5857 3.0000 0.2500 2.7500 1.6583 1.1254 3.51 0.32 3.32 6.02 2,702 3,891,509 5.35
8.00 0.67 1.3593 3.0000 9.0000 2.3333 0.7778 0.6797 4.0000 0.4444 3.5556 1.8856 1.7173 4.08 0.42 3.77 11.03 4,950 7,127,357 6.42
9.00 0.75 1.4455 3.0000 9.0000 2.2500 0.7500 0.7227 4.5000 0.5625 3.9375 1.9843 2.0399 4.34 0.47 3.97 14.10 6,330 9,114,931 6.91
12.00 1.00 1.6821 3.0000 9.0000 2.0000 0.6667 0.8411 6.0000 1.0000 5.0000 2.2361 3.0975 5.05 0.61 4.47 25.57 1 11,477 16,526 606 8.26
15.00 1.25 1.8959 3.0000 9.0000 1.7500 0.5833 0.9480 7.5000 1.5625 5.9375 2.4367 4.2675 5.69 0.75 4.87 40.28 18,077 26,030,573 9.44
18.00 1.50 2.0944 3.0000 9.0000 1.5000 0.5000 1.0472 9.0000 2.2500 6.7500 2.5981 5.5277 6.28 0.88 5.20 58.01 26,036 37,492 140 10.50
21.00 1.75 2.2820 3.0000 9.0000 1.2500 0.4167 1.1410 10.5000 3.0625 7.4375 2.7272 6.8602 6.85 1.00 5.45 78.53 35,242 50,748,573 11.45
24.00 2.00 2.4619 3.0000 9.0000 1.0000 0.3333 1.2310 12.0000 4.0000 8.0000 2.8284 8.2502 7.39 1.12 5.66 101.53 45,566 65,614 870 12.31
27.00 2.25 2.6362 3.0000 9.0000 0.7500 0.2500 1.3181 13.5000 5.0625 8.4375 2.9047 9.6845 7.91 1.22 5.81 126.71 56,866 81,887,114 13.08
30.00 2.50 2.8067 3.0000 9.0000 0.5000 0.1667 1.4033 15.0000 6.2500 8.7500 2.9580 11.1511 8.42 1.32 5.92 153.72 68,989 99,344 411 13.79
33.00 2.75 2.9747 3.0000 9.0000 0.2500 0.0833 1.4874 16.5000 7.5625 8.9375 2.9896 12.6389 8.92 1.42 5.98 182.20 81,771 117,749,867 14.42
36.00 3.00 3.1416 3.0000 9.0000 0.00001 0.0000 1.5708 18.0000 9.0000 9.0000 3.0000 14.1372 9.42 1.50 6.00 211.75 95,035 1136,850,805 14.98
39.00 3.25 3.3085 3.0000 9.0000 -0.2500 -0.0833 1.6542 19.5000 10.5625 8.9375 2.9896 15.6354 9.93 1.58 5.98 241.97 108,596 156,378,245 15.48
42.00 3.50 3.4765 3.0000 9.0000 -0.5000 -0.1667 1.7382 21.0000 12.2500 8.7500 2.9580 17.1232 10.43 1.64 5.92 272.40 122,254 176 045,575 15.91
45.00 3.75 3.6470 3.0000 9.0000 -0.7500 -0.2500 1.8235 22.5000 14.0625 8.4375 2.9047 18.5898 10.94 1.70 5.81 302.58 135,796 195,546,186 16.28
48.00 4.00 3.8213 3.0000 9.0000 -1.0000 -0.3333 1.9106 24.0000 16.0000 8.0000 2.8284 20.0241 11.46 1.75 5.66 331.98 148,993 214 549,597 16.58
51.00 4.25 4.0011 3.0000 9.0000 -1.2500 -0.4167 2.0006 25.5000 18.0625 7.4375 2.7272 21.4141 12.00 1.78 5.45 360.06 161,594 232,695,261 16.81
54.00 4.50 4.1888 3.0000 9.0000 -1.5000 -0.5000 2.0944 27.0000 20.2500 6.7500 2.5981 22.7467 12.57 1.81 5.20 386.19 173,321 249 582,391 16.98
57.00 4.75 4.3872 3.0000 9.0000 -1.7500 -0.5833 2.1936 28.5000 22.5625 5.9375 2.4367 24.0068 13.16 1.82 4.87 409.66 183,856 264,752,440 17.06
60.00 5.00 4.6010 3.0000 9.0000 -2.0000 -0.6667 2.3005 30.0000 25.0000 5.0000 2.2361 1 25.1769 13.80 1.82 4.47 429.63 192,817 277 656,488 17.06
63.00 5.25 4.8377 3.0000 9.0000 -2.2500 -0.7500 2.4189 31.5000 27.5625 3.9375 1.9843 26.2344 14.51 1.81 3.97 444.99 199,713 287,586,888 16.96
66.00 5.50 5.1118 3.0000 9.0000 -2.5000 -0.8333 2.5559 33.0000 30.2500 2.7500 1.6583 27.1489 15.34 1.77 3.32 454.15 203,823 293 504,557 16.73
69.00 5.75 5.4609 3.0000 9.0000 -2.7500 -0.9167 2.7305 34.5000 33.0625 1.4375 1.1996 27.8712 16.38 1.70 2.40 454.02 203,766 293,422,531 16.29
72.00 6.00 6.2832 3.0000 9.0000 -3.0000 -1.0000 3.1416 36.0000 36.0000 0.0000 0.0000 28.2743 18.85 1.50 0.00 423.51 190,071 273 701,610 14.98

ALBEMARLE" HATC H
Albemarle- Kings Mountain Mine Select EPCM
Construction Stormwater Management Plan —July 12, 2024
Appendix E:
Channel and Culvert Capacity Analysis
Results
H371132-4000-220-230-0001, Rev. C
©Hatch 2024 All rights reserved,including all rights relating to the use of this document or its contents.

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Monday, Oct 9 2023
Grass Swale @ 1 % slope, 2.5 ft depth
Trapezoidal Highlighted
Bottom Width (ft) = 6.00 Depth (ft) = 2.00
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 108.96
Total Depth (ft) = 3.00 Area (sqft) = 24.00
Invert Elev (ft) = 850.00 Velocity (ft/s) = 4.54
Slope (%) = 0.60 Wetted Perim (ft) = 18.65
N-Value = 0.030 Crit Depth, Yc (ft) = 1.65
Top Width (ft) = 18.00
Calculations EGL (ft) = 2.32
Compute by: Q vs Depth
No. Increments = 3
Elev (ft) Section Depth (ft)
854.00 4.00
853.00 3.00
852.00 2.00
851.00 1.00
850.00 0.00
849.00 -1.00
0 5 10 15 20 25 30 35
Reach (ft)

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Monday, Oct 9 2023
Grass Swale @ 1 % slope, 2.5 ft depth
Trapezoidal Highlighted
Bottom Width (ft) = 6.00 Depth (ft) = 2.00
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 108.96
Total Depth (ft) = 3.00 Area (sqft) = 24.00
Invert Elev (ft) = 850.00 Velocity (ft/s) = 4.54
Slope (%) = 0.60 Wetted Perim (ft) = 18.65
N-Value = 0.030 Crit Depth, Yc (ft) = 1.65
Top Width (ft) = 18.00
Calculations EGL (ft) = 2.32
Compute by: Q vs Depth
No. Increments = 3
Depth (ft) Performance Curve Elev (ft)
4.00 854.00
3.00 853.00
2.00 852.00
0000/
1.00 851.00
0.0 25 50 75 100 125 150 175 200 225 250 275
Normal Depth Q (cfs)

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Monday, Oct 9 2023
Rip-Rap Channel @ 1.4% Slope, 3 ft depth
Trapezoidal Highlighted
Bottom Width (ft) = 5.00 Depth (ft) = 2.40
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 188.55
Total Depth (ft) = 3.00 Area (sqft) = 29.28
Invert Elev (ft) = 850.00 Velocity (ft/s) = 6.44
Slope (%) = 1.40 Wetted Perim (ft) = 20.18
N-Value = 0.035 Crit Depth, Yc (ft) = 2.31
Top Width (ft) = 19.40
Calculations EGL (ft) = 3.04
Compute by: Q vs Depth
No. Increments = 10
Elev (ft) Section Depth (ft)
854.00 4.00
853.00 3.00
v
852.00 2.00
851.00 1.00
850.00 0.00
849.00 -1.00
0 5 10 15 20 25 30 35
Reach (ft)

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Monday, Oct 9 2023
Rip-Rap Channel @ 1.4% Slope, 3 ft depth
Trapezoidal Highlighted
Bottom Width (ft) = 5.00 Depth (ft) = 2.40
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 188.55
Total Depth (ft) = 3.00 Area (sqft) = 29.28
Invert Elev (ft) = 850.00 Velocity (ft/s) = 6.44
Slope (%) = 1.40 Wetted Perim (ft) = 20.18
N-Value = 0.035 Crit Depth, Yc (ft) = 2.31
Top Width (ft) = 19.40
Calculations EGL (ft) = 3.04
Compute by: Q vs Depth
No. Increments = 10
Depth (ft) Performance Curve Elev (ft)
3.00 853.00
2.00 852.00
1.00 851.00
0.00 850.00
0.0 25 50 75 100 125 150 175 200 225 250 275 300 325
Normal Depth Q (cfs)