Kewaunee Warehouse Expansion - 2016-090 SWMR

STORMWATER MANAGEMENT
REPORT

PREPARED FOR

Kewaunee Warehouse Expansion

2340 W. Front St.

Statesville, NC

August 27, 2018

By:

P. Scott Bell, PE

PROJECT NARRATIVE:

The site is located on the North side of W. Front Street, between Autec and Mt. Aire
Farms properties in West Statesville. The southern boundary is W. Front Street, and the
northern side of the site is bounded by Alexander RY rail site. Site soils are Urban Land
based on mapping from NRCS - Iredell. The site is predominantly developed, with a
berm along the railway right of way. This phase of development will be complete build
out for this parcel. The site currently has a 100,000 SF warehouse, associated docks
and parking as shown on existing conditions sheet C0.1. There is also an existing dry
detention pond between the building and W. Front Street. Design parameters for outlet
structure are shown on the existing conditions plan as well

Existing utilities (water, sewer, electricity, gas) are available onsite.

The storm drainage calculations are based on the rational method. Drainage area maps
for the pre-developed and post-developed conditions are attached (sheets D-1and D-2).
Following each map is a data table used to calculate the composite CN, and composite
rational “C” values. Calculations for peak discharge were determined using an excel
spreadsheet. These flow rates were then used in Carlson Hydraulic modeling software
to determine culvert size based on flowing 50% full during a 10 year storm event.

Permanent storm water quantity is being provided on this site by converting the dry
pond and existing outlet structure to a wet pond. Calculations for design are included
with this submittal. The proposed system attenuates the post-developed flows for the 1
year, 2 year, and 10 year storm events (see page 2 of the Hydraflow calculations for a
summary).

The site slopes from north to south, toward the existing dry pond. Earthworks for the site
will require export of structural fill and topsoil. Some topsoil from this site will be used on
fill and cut slopes to insure that vegetation is established promptly after work is
complete, excess will be transported to a nearby site, to be permitted separately, but
concurrently with this submittal.

Stormwater runoff shall be collected by use of swales, drainage piping, temporary slope
drains, catch basins, and ADS Nyoplast inlets. The storm drainage is designed for a 10-
year storm frequency. Silt fence, straw wattles, and sediment fence rock outlets will be
constructed and maintained in accordance with the plans and project details.

Erosion Control Plan has been to Iredell County Development Services, Planning
Division – Erosion Control Section on August 30, 2018.

Table of Contents 1:

USGS Quad, Statesville West EX-A
Pre-developed Drainage Area Map D-1
Pre-developed Composite CN 2
Post-developed Drainage Area Map D-2
Post-developed Composite CN 3
MDC Investigation 4
Current Deed 10
Deed Restrictions 13
Secretary of State LP filing 15
Storm EZ Application 17

Attachments:

Hydraflow pre-developed hydraulic analysis
Hydraflow post-developed hydraulic analysis

USGS Quad, Statesville West,

Exhibit A

Project: 2016-090 Kewaunee Warehouse ExpansionDate: 8/27/2018Title: Pre-developed Composite CNname total sub CN c composite Composite Tcacreage acreageCN C DI-2 0.57298 0.21 impervious 98 0.95 93 0.81 50.07 gravel 85 0.40.23 building 98 0.950.05 grass 61 0.20.00 wooded 55 0.15DI-3 1.33285 1.14 impervious 98 0.95 95 0.86 50.07 grass 61 0.20.13 gravel 85 0.4DI-4 0.81921 0.54 impervious 98 0.95 90 0.73 50.11 grass 61 0.20.18 gravel 85 0.4DI-5 2.06655 0.00 impervious 98 0.95 81 0.26 51.40 grass 79 0.20.66 gravel 85 0.4B-2 2.37796 1.24 impervious 98 0.95 83 0.60 50.00 gravel 85 0.41.14 grass 61 0.2OS-1 2.82153 0.25 impervious 98 0.95 72 0.33 51.64 grass 61 0.20.92 gravel 85 0.4pre-developed 9.99109 3.37 impervious 98 0.95 79 0.511.97 gravel 85 0.40.23 building 98 0.954.41 grass 61 0.20.00 wooded 55 0.15
Project: 2016-090 Kewaunee Warehouse ExpansionDate: 8/27/2018Title: Post-developed Composite CNname total sub CN c composite Composite Tcacreage acreageCN C DI-2 0.57298 0.21 impervious 98 0.95 93 0.81 50.07 gravel 85 0.40.23 building 98 0.950.05 grass 61 0.20.00 wooded 55 0.15DI-3 1.332851 1.14 impervious 98 0.95 95 0.86 50.07 grass 61 0.20.13 gravel 85 0.4DI-4 0.819215 0.54 impervious 98 0.95 90 0.73 50.11 grass 61 0.20.18 gravel 85 0.4DI-5 0.565427 0.47 impervious 98 0.95 94 0.84 50.05 grass 61 0.20.04 gravel 85 0.4B-2 3.310468 1.79 impervious 98 0.95 81 0.61 50.00 gravel 85 0.41.52 grass 61 0.2OS-1 2.150482 0.25 impervious 98 0.95 76 0.37 50.98 grass 61 0.20.92 gravel 85 0.40.00 wooded 55 0.15DI-6 1.267539 0.76 impervious 98 0.95 85 0.67 50.41 grass 61 0.20.10 gravel 85 0.4post-developed 10.01896 5.16 impervious 98 0.95 84 0.631.44 gravel 85 0.40.23 building 98 0.953.18 grass 61 0.20.00 wooded 55 0.15
MDC Investigation:

STORAGE VOLUME
CALCULATIONS

Drainage Area: 9.98 Ac.
Runoff Depth (Rd): 1.4 inch

RUNOFF VOLUME TO
TREAT:
Rv=0.05+0.9Ia

Pre-Development Area:
Impervious 3.6 Ac.
Gravel 1.97 Ac.
Grass: 4.41 Ac.
Woods: 0 Ac.
Total: 9.98 Ac.

Post-Development
Area:
Impervious 5.39 Ac.
Gravel 1.41 Ac.
Grass: 3.18 Ac.
Woods: Ac.

Total: 9.98 Ac.

Ia: 0.681
Rv= 0.663

Volume to Treat:

Minimum Temporary
Pool Volume
V=3630xRdxRvxA

V= 33,638 C.F.

Volume provided 34,809 cf

Permanent
Pool
Calculations

Average
Depth; dave =
[0.25x(1+Abs/App)] +
[(Abs+Abp)/2 x
(d/Abs)]

Abs:
Surface area at bottom
shelf (includes main
pond & forebay)
App:
Surface area at
permanent pool
(includes main pond &
forebay)
Abp:
Surface area at bottom
of pond excluding
sediment storage
d:
distance between
bottom of shelf &
bottom of pond exc.
sediment storage

Abs: 9,438 S.F.
App: 12,250 S.F.
Abp: 4,427 S.F.
d: 3.5 ft.

dave = 3.0 ft.

SA/DA
(Driscoll,
1986): 2.51

Drainage Area: 9.98 Ac.

Minimum
surface
required:
SA :

10,912

Surface Area
provided: 15,388

Minimum sediment storage in main pool and forebays is 1 ft

Pond has 2 forebays (hence, 2 inlets), and the outlet structure is placed midway
between the two inlets.

Volume of the main pool is 19,704 cf.
Volume of Forebay 1 = 1,974 cf
Volume of Forebay 2 = 2,692 cf

Vf/Vp >0.20, (2,692 cf + 1,974 cf)/19,704 cf = 0.236; 23.6 %

The main pool as designed has a 10' vegetated shelf around its perimeter, and has a
cross slope of 10% (10ft hor : 1 ft vert)

Orifice Equation

Q=CdA(2gH)1/2

Cd=0.6
A=∏r2
H=H/3

Pipe Size Area H H/3
(inches) (S.F.) (feet) (feet)
2 0.02 6.2 2.07

V= 38,119 cf
Temporary Pool
Volume
Q= 0.15 cfs
Drawdown= 252421 sec

Drawdown= 2.92 days

Discharge point for pond is an existing concrete drop inlet in the curb of West Front
Street.

There is no proposed fountain.

High Density Commercial Subdivisions
Deed Restrictions & Protective Convenances
Form DRPC-1 Rev.2 05Nov2009 Page 1 of 2

In accordance with Title 15 NCAC 2H.1000 and S.L. 2006-246, the Management Regulations, deed
restrictions and protective covenants are required for High Density Commercial Subdivisions where
lots will be subdivided and sold and runoff will be treated in an engineered stormwater control facility.
Deed restrictions and protective covenants are necessary to ensure that the development maintains a
built-upon area consistent with the design criteria used to size the stormwater control facility.

I, _Tom Wilson Sr._______________________________, acknowledge, affirm and agree by my
signature below, that I will cause the following deed restrictions and covenants to be recorded prior to
the sale of any lot within the project known as _Kewaunee Warehouse Addition__________________:

1. The following covenants are intended to ensure ongoing compliance with State Stormwater
Management Permit Number ________________, as issued by the Division of Energy, Mineral
and Land Resources under the Stormwater Management Regulations.

2. The State of North Carolina is made a beneficiary of these covenants to the extent necessary to
maintain compliance with the stormwater management permit.

3. These covenants are to run with the land and be binding on all persons and parties claiming
under them.

4. The covenants pertaining to stormwater may not be altered or rescinded without the express
written consent of the State of North Carolina, Division of Energy, Mineral and Land Resources.

5. Alteration of the drainage as shown on the approved plan may not take place without the
concurrence of the Division of Energy, Mineral and Land Resources.

6. The maximum allowable built-upon area per lot is ___n/a________square feet.

*Note: If the BUA per lot varies, please substitute the following statement for the one above and
provide a complete listing of the proposed BUA for each lot:

The maximum built-upon area per lot, in square feet, is as listed below:

Lot # BUA Lot # BUA Lot # BUA Lot # BUA
_____ _____ _____ _____ _____ _____ _____ _____

This allotted amount includes any built-upon area constructed within the lot property boundaries,
and that portion of the right-of-way between the front lot line and the edge of the pavement. Built
upon area includes, but is not limited to, structures, asphalt, concrete, gravel, brick, stone, slate,
coquina and parking areas, but does not include raised, open wood decking, or the water
surface of swimming pools.

7. All runoff from the built-upon areas on the lot must drain into the permitted system. This may be
accomplished through a variety of means including roof drain gutters which drain to the street,
grading the lot to drain toward the street, or grading perimeter swales to collect the lot runoff
and directing them into a component of the stormwater collection system. Lots that will naturally
drain into the system are not required to provide these additional measures.

8. The owner of each lot, whose ownership is not retained by the permittee, is required to submit a
separate stormwater permit application to the Division of Energy, Mineral and Land Resources
and receive a permit prior to construction.

9. The project and each lot will maintain a 30** foot wide vegetated buffer between all impervious
areas and surface waters.

**50 foot for projects located in the 20 coastal counties.

STATESVILLE, NC IREDELL County
n/a,
Type of application:
Initials
1
2 PSB
3 PSB
4 PSB
PSB
PSB
PSB
PSB
PSB
PSB
PSB
PSB
PSB
PSB
PSB
PSB
PSB
PSB
PSB
PSB
PSBLANDSCAPE PLAN (C3.0)
d. The boundaries of all surface waters, regulatory flood zones, and protected
riparian buffers or a note on the plans that none exist.
b. Location map with street names and SR numbers, legend, north arrow,
scale.
a. Project name, engineer and firm, revision number and dates.
N/A
GRADING PLAN (C2.0)
e. The boundaries of all vegetated or protected riparian buffers.
SITE PLAN (C1.0)
EXISTING CONDITIONS (C0.1)
SITE DETAILS (C1.1)
ATTACHED PSB
Click here for Express Permitting info
A PROPOSED EXPANSION FOR KEWAUNEE SCIENTIFIC
STATESVILLE, NC IREDELL County
A copy of the most current property deed.
Two copies of additional calculations (as needed). Sealed, signed and dated.
LOCATED IN CALCULATIONS
LOCATED IN CALCULATIONS
ATTACHED
Two sets of sealed, signed, & dated full-sized plans of the entire site at a
readable scale, including:
ATTACHED
Part I: Submittal Checklist
Application
New Permit
Notes / Comments
Original and one copy of this application form (all worksheets) and the permit
application fee. For applications submitted to the DEMLR regular permitting
program, the fee is $505 payable to NCDENR. For Express Review, click on the
link below for information and fee schedule. Contact the appropriate regional
office Express Review Coordinator to schedule the required pre-application
meeting.
A USGS map identifying the site location. If the receiving stream is reported as
class SA or the receiving stream drains to and is within 1/2 mile of SA waters,
then include the 1/2 mile radius on the map.
d. Specifications for applicable materials, such as planting media, aggregate,
sod, underdrains, outlet devices, etc.
SITE DETAILS (C1.1)
COVER (CVR)
EXISTING CONDITIONS (C0.1)
N/A
SITE PLAN (C1.0)
c. A table of elevations, incremental volumes and accumulated volumes (if
applicable).
a. Dimensions, side slopes, length to width ratios and elevations with a
benchmark for clean-out if appropriate.
b. All applicable conveyance devices, including: bypass structure,
pretreatment area, flow distribution device, underdrains, outlet device, outlet
dissipater and level spreader.
Two sets of sealed, signed, & dated full-sized plan details of each SCM (or
typical if appropriate) in both plan view and cross-section at a scale of 1" = 30' or
larger, including:
k. A construction sequence that shows how the SCMs will be protected from
sediment until the entire drainage area is stabilized.
c. Dimensioned property/project boundary with bearings & distances.
EROSION CONTROL PLAN
(C4.0)
LOCATED IN CALCULATIONS
f. Site layout showing all built-upon areas, drainage features, stormwater
collection systems (inlets, outlets, swales, pipe elevations, slopes and
diameters), and SCMs at ultimate build-out.
g. Existing contours, proposed contours, spot elevations, and finished floor
elevations.
h. Existing drainage (including off-site), drainage easements, pipe sizes,
runoff calculations.
ALL SHEETS
Only complete application packages will be accepted and reviewed. A complete package includes all of the items in the checklist
below. Add any comments, and indicate the page or plan sheet number where the following information can be found. Please
indicate that you have provided the following required information by initialing in the space provided next to each item.
Item
6
SHEET D-1 AND D-2
SITE DETAILS (C1.1)
5
i. Drainage area boundaries (included in the main set of plans, not as a
separate document).
j. Existing and proposed maintenance access routes, utility easements,
drainage easements, public rights-of-way etc.
STORM-EZ
Version 1.4 Application
9/6/2018
Page 1 of 17
STATESVILLE, NC IREDELL County
n/a,
PSB
PSB
PSB
PSB
PSB
8 PSB
9 PSB
10 PSB
11 PSB
12 PSB
LANDSCAPE PLAN (C3.0)
ATTACHED
7
For corporations and limited liability corporations (LLC): Documentation from the
NC Secretary of State or other official documentation, which supports the titles
and positions held by the persons listed in the Contact Information section. The
corporation or LLC must be listed as an active corporation in good standing with
the NC Secretary of State, otherwise the application will be returned.
N/A
N/A
ATTACHED
NCDENR Deed Restriction Forms
ATTACHED
c. The source nursery for the plants.
A copy of the signed and notarized operation and maintenance (O & M)
agreement.
a. The locations of each species and a planting detail.
b. A table summarizing the size, spacing and total quantity of each plant
species that should be used.
A copy of the lease agreement or pending sales agreement if applicable.
NC Dept. of the Secretary of State
A soils report based on field evaluation indicating the SHWT elevations within
the footprints of the proposed SCM(s). Provide a map of the boring locations
with the existing elevations and boring logs. For infiltration SCMs, the report
shall include the soil type, infiltration rate and method for determining the
infiltration rate. Soils information shall be signed and sealed by a licensed soil
scientist.
N/A
Two sealed, signed, & dated planting plans for each SCM (or typical) at a scale
of 1" = 20' or larger, as applicable, including:
N/A
LANDSCAPE PLAN (C3.0)
d. A one-time fertilizer specification to establish plants if necessary.
A copy of the proposed deed restrictions protecting the SCMs and limiting the
built-upon area so that it does not exceed the capacity of the SCM(s) or the high
density threshold (as applicable).
STORM-EZ
Version 1.4 Application
9/6/2018
Page 2 of 17
STATESVILLE, NC IREDELL County
n/a,
Date:
Lat:
Zip:Long:
County:
Project Applicant:
Owner / Signing Offical's Name:
Title:
Address:
City:
State:
Zip:
Phone:
Fax:
Email:
Status of applicant:
River Basin:
Receiving Stream(s):
Stream Class(es):
Surface Water Area (ac):Coastal wetland area (ac):
Total property area (ac):Total project area (ac):
Goals/characteristics:NO Volume Matching (LID) YES Drains to an offsite stormwater system
NO Low Density NO Within 575' of Saltwater ORW
YES High Density YES Within 5 miles of a public airport
Briefly summarize how the stormwater runoff will be treated:

Status of construction:
Other permits needed: YES Sedimentation & erosion control NO 404 Permit / 401 Certification
NO CAMA Major Permit NO Isolated Wetlands Permit
NO Threatened & Endangered Species NO NPDES Industrial Stormwater Permit
If an application for this project has been previously returned, provide the original project number and previous name of the project:
Provide the permit type, number and issue date for any permits that have already been obtained for this project:

If claiming vested rights, then identify (and attach) the supporting documents and approval dates:
NO Approval of a site-specific development plan or PUD Approval date:
NO Valid building permit Issue date:
NO Other Date:
Not Started
Point of Contact:Phone number:
6-Sep-18
IREDELL
2340 W FRONT STREET
n/a
Not Started
Project Name:
City:
Yadkin
(from nearest intersection)
(Identify the corporation, organization, property owner, designated
government official, etc. which owns the project .)
28677
704-872-2411
Owner
NON-COASTAL
c
n/a
n/a
n/a
9.9
UT to Third Creek
[e-mail]
28625
0
TOM WILSON SR
STATESVILLE
n/a
704-872-8281
NC
80-55-35
G.L. WILSON BUILDING CO.
Directions to Project:
A PROPOSED EXPANSION FOR KEWAUNEE SCIENTIFIC
35-47-32
Part III: Permit Information
ON W FRONT STREET, 1100 FEET WEST OF INTERSECTION OF W
FRONT ST AND MEACHAM RD
3.5
n/a
n/a
BMP Wet Pond
n/a
n/a
STATESVILLE
190 WILSON PARK RD
Project Street Address:
Part II: General Project and Applicant Information
STORM-EZ
Version 1.4 Application
9/6/2018
Page 3 of 17
1.00
1.40
1.86
2.78
3.36
4.89
5.80
6.53
7.27
Highlighted Storm is Design Storm
0.00 acres 5.16 acres
0.00 acres 52%
0.00 acres
Complete the breakdown of impervious area for the project
Yes
2-yr, 24-hr
Storm Event
10-yr, 24-hr
25-yr, 24-hr(Minimum Design Storm = P90 for non-SA, 1-yr, 24-hr for SA)
Loaded Rainfall:
0
156,816
Entire Site
Total Impervious Area
Project % impervious area
ALL AREAS ARE IN SQUARE FEET
100-yr, 24-hr
PROJECT INFORMATION
RAINFALL & CALCULATION DATA
Rainfall Source:
Project County:
Project City:
IREDELL
STATESVILLE
Charlotte
Design Storm:
Charlotte
1-yr, 24-hr
A PROPOSED EXPANSION FOR KEWAUNEE SCIENTIFIC
STATESVILLE, NC IREDELL County
Yadkin River Basin
Depth
(inches)
P90
First Flush / WQV
P90
P95
50-yr, 24-hr
Total Property Area
Total Coastal Wetlands Area
Total Surface Water Area
UT to Third Creek
c
Use Worksheet Data?
Total Drainage Area
On-Site Drainage Area (sf)
12-108-20-4
435,164
435,164
Data in italics is derived from application
forms and land use data worksheets and
cannot be changed by user.
Proposed Impervious Area (sf)
% Impervious Area (total)
0
224,866
52%
On-Site Buildings/Lots (sf)
On-Site Streets (sf)
50,000
0
Other On-Site (sf)
17,055
995
0
On-Site Parking (sf)
On-Site Sidewalks (sf)
Future (sf)
Off-site (sf)
Existing BUA (sf)
224,866Total
0
Impervious Surface Area
Offsite Drainage Area (sf)
Stream Index Number
Stream Class
Receiving Stream name
Basin Information Entire Site
NOTE: Please use the Storm-EZ calculation sheets to document the stormwater design
and create the O&M Agreement.
Discrete SCS Method,
Pre - PostCalculation Method
STORM-EZ
Version 1.4 Project Data
9/6/2018
Page 5 of 17
1 of 1
Pre-Development Land Use:
HSG CN %
B 61 63.89%
B 98 36.11%
Note: Enter BUA Draining to
Permeable Pavement Below
HSG
0.00 0.00%
0.00 0.00%
0.00 0.00%
0.00 0.00%
0.00 0.00%
9.99 36.11%
Existing Permeable Pavement (Infiltration):
Pavement Area Additional BUA
Soil
Infiltratio
n Rate
Gravel
Void Space
Total
Gravel
Depth
Orifice
Dia.
Orifice
Height
(sf) (sf) (in/hr) (%) (in) (in) (in)
100 0
DSD PAW Dgr
(in) (%) (in) (sf) (acres)
150 1.40 0.00
9.99 acres
0.00 acres
0.00 acres
0.00 acres
0.00 acres
9.99 acres
Pre-Development SCMs:
Imp. Open
(sf) (sf)
(cf) HSG 157135 277984
200 38119 B 146235 166071
Rainfall Volume =13.98 cf
Natural Infiltration & ET =-9.71 cf
Disconnected Impervious Surfaces =0.00 cf
SCM Infiltration =-0.20 cf
Permeable Pavement Infiltration =0.00 cf
Green Roof ET =0.00 cf
Post Filtration Discharge =0.00 cf
Total Runoff Reduction =-9.91 cf
Treated SCM Outflow =-1.99 cf
Untreated Surface Runoff =2.09 cf
435,119
0
0
-35,959
-35,237
0
-722
0
SCM Treatment:
acre-inches =7,589
The Pre-Development project area contains 157135 sf of built upon area, resulting in an overall density of 36.11%.
-7,216
acre-inches =
acre-inches =
acre-inches =
acre-inches =
acre-inches =
acre-inches =
BUA %
SCM #
SCM #
From Land Use Tables: 435,119
Preserved Surface Waters & Non-Coastal Wetlands :
0
Runoff Reduction Components:
acre-inches =
50,764acre-inches =
acre-inches =
Design Storm Runoff Fate Summary:
435,119
Subtotal:
A PROPOSED EXPANSION FOR KEWAUNEE SCIENTIFIC
(acres)
3.61Impervious
Pasture or Open Space 277,984
157,135
STATESVILLE, NC IREDELL County
Yadkin River Basin
PRE-DEVELOPMENT LAND USE CALCULATIONS
Drainage Area #
(sf)Land-use
6.38
Area
0
User Defined Drainage Areas:Comp.
CNDescription
Area
(ac.)Area (sf.)
Subtotal:
Area (sf.)
WQ Volume
Provided
% Imp
Drainage Area
435,119 9.99
0
Downstream
SCM
Description
Total Site Area:
Land Use Summary:
Description
Preserved Coastal Wetlands :
NotesSCM #
Area DS SCM #
Has Synthetic
Liner?
Permeable Pavement + Additional BUA:
Green Roofs :
0
Existing Green Roofs:
HSG
SCM Type
Dry Detention
D.S.
BMP
STORM-EZ
Version 1.4 Pre-Development
9/6/2018
Page 6 of 17
1 of 1
Permeable Pavement:
Infiltration
Rate Void Space
Total
Gravel
Depth
Orifice
Dia.
Orifice
Height
(sf) (acres) (sf) (acres) (in/hr) (%) (in)(in) (in)
500 0 0.00 0.00 No
DSD PAW Dgr
(in) (%) (in) (sf) (acres)
600 1.40 0% 0.00 No
Residential Lot CN Calculator (Excluding R/W and dedicated open spaces):
Max Imp / Lot Woods / Lot
(ac.)(sf) (sf)
0.00
Remaining Land Use:
HSG CN (sf) (acres) %
B 98.0 235,087 5.40 54.03%
B 61.0 200,032 4.59 45.97%
N/A 0 0.00 0.00%
N/A 0 0.00 0.00%
435,119 9.99 100.00%
Land Excluded, or Partially Excluded, from Volume Calculations:(sf.) (ac.)
0 0.00
0 0.00
435,119 9.99
Rainfall Volume =13.98 cf
Natural Infiltration & ET =-7.60 cf
Disconnected Impervious Surfaces =0.00 cf
SCM Infiltration =-0.58 cf
Permeable Pavement Infiltration =0.00 cf
Green Roof ET =0.00 cf
Post Filtration Discharge =0.00 cf
Total Runoff Reduction =-8.18 cf
Comments
Check PAW
Retrofit?
Drainage Area #
Down-
stream
SCM
Additional BUA
SCM #
Downstream
SCM #
HSG
Avg Lot Size
Pavement Area
Permeable Pavement + BUA:
Sub-Total:
Green Roofs:
# of Lots
Land-Use
Open Space (Managed Open Space)
% Imp.(sf.)
Lot Area
Impervious
Total Site Area:
Surface Waters & Non-Coastal Wetlands :
Green Roofs :
Coastal Wetlands :
acre-inches =
-2,105
0
-29,680
A PROPOSED EXPANSION FOR KEWAUNEE SCIENTIFIC
STATESVILLE, NC IREDELL County
Yadkin River Basin
Detention
Check
Has
Synthetic
Liner?
Infiltration
Check
POST-DEVELOPMENT LAND USE CALCULATIONS
Pvmt Type
SCM #
Area
Runoff Reduction Components:
Design Storm Runoff Fate Summary:
acre-inches =
acre-inches =
acre-inches =
acre-inches = -27,575
acre-inches =
0
0
acre-inches =
0
Area
Open Space / Lot
(sf)
50,764
acre-inches =
STORM-EZ
Version 1.4 Post Development 9/6/2018
Page 7 of 17
1 of 1Drainage Area #
A PROPOSED EXPANSION FOR KEWAUNEE SCIENTIFIC
STATESVILLE, NC IREDELL County
Yadkin River Basin
POST-DEVELOPMENT LAND USE CALCULATIONS
Treated SCM Outflow =-5.51 cf
Untreated Surface Runoff =0.30 cf
Pre-Development Runoff =2.09 cf
Difference =-1.79 cf
acre-inches =
acre-inches =-19,996
SCM Treatment:
1,088
acre-inches =-6,501
acre-inches =7,589
The Post-Development project area contains 235087 sf of built upon area, resulting in an overall density of 54.03%.
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Impervious
(sf)
235,087 (cf) (cf) (cf) (cf) (cf) (cf)
700 proposed pond Wet Detention B 224,197 95% 59%143835 22101 22101 2105 0 19996 15%
Rainfall Volume =13.98 acre-inches =cf
Natural Infiltration & ET =-7.60 acre-inches = cf
Disconnected Impervious Area =0.00 acre-inches = cf
SCM Infiltration =-0.58 acre-inches = cf
Permeable Pavement Infiltration =0.00 acre-inches = cf
Green Roof ET =0.00 acre-inches = cf
Post Filtration Discharge =0.00 acre-inches = cf
Total Runoff Reduction =-8.18 acre-inches =cf
SCM Treatment:
Treated SCM Outflow =-5.51 acre-inches =cf
Untreated Surface Runoff =0.30 acre-inches =cf
2.09 acre-inches =cf
-1.79 acre-inches =cf
STORMWATER CONTROL MEASURES
% of SCM
Volume
Utilized
Post
Filtration
Outflow
Treated
Outflow
Type of Device
SCM
#Name / Location
Contributing Area
HSG
Note: Large storage devices such as wet/dry detention ponds, constructed wetlands, or infiltration basins may require pond routing calculations. The routing calculations should be provided in addition to this spreadsheet.
117,247
% of Total
Impervious
Area
% of Total
Pervious
Area
Storage
Volume
Offsite Impervious
Area Treated
Infiltration &
ET
0 sf
Total
Inflow
Volume
Enter only runoff volume below that will be infiltrated or drawn down over 2 to 5 days. Additional volume provided in devices should not be entered in this worksheet.
Drawdown time requirement applies to all storm events.
Drainage Area #
PROPOSED SIPs & STRUCTURAL RUNOFF VOLUME CONTROLS
A PROPOSED EXPANSION FOR KEWAUNEE SCIENTIFIC
STATESVILLE, NC IREDELL County
Yadkin River Basin
0
117247 sf open space entered
compared to 200032 sf total
open space.
Pervious
(sf)
200,032
7,589
Warnings:
Design Storm Runoff Fate Summary:
The Post-Development project area contains 235087 sf of built upon area, resulting in an overall density of 54.03%.
0
0
**BASIC TREATMENT MET**
Difference =
Pre-Development Runoff =
-19,996
1,088
95% of total
impervious
area.
59% of total
pervious
area.
Runoff Reduction Components:
-27,575
224197 sf impervious area entered
compared to 235087 sf total impervious.
Down-
stream SCM
#
Drainage
Area Inflow
Volume
-6,501
-29,680
-2,105
0
50,764
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Compliance Storm = P90 Storm - Rainfall Depth = 1.4 inches
Drainage Area #
FATE OF RAINFALL
Select Storm:
The"Fate of Rainfall" charts display the hydrologic processes to which rainfall volumes are subjected based on the combinations of land use, soil type, and stormwater controls entered by the user. The charts are designed to display the stormwater
plan in a form which illustrates changes to the hydrologic cycle which result from urbanization and various stormwater management strategies.
STATESVILLE, NC IREDELL County
Yadkin River Basin
P90
A PROPOSED EXPANSION FOR KEWAUNEE SCIENTIFIC
P90 Storm - Rainfall Depth = 1.4 inches
VOLUME MATCHING SCALE
Volume Matching Threshold
Basic Treatment Threshold
BASIC TREATMENT SCALE
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Infiltration and ET - 29680 cf Treated Outflow from BMPs - 19996 cf Untreated Surface Runoff - 1088 cf% of Total Rainfall VolumePost Development Fates
Post Filtration Outflow - 0 cf
Other
Infiltration by BMPs - 2105 cf
Permeable Pavement Infiltration - 0 cf
Disconnected Impervious Infiltration - 0 cf
Green Roof Evapotranspiration - 0 cf
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Infiltration and ET - 36549 cf Treated Outflow from BMPs - 13120 cf Untreated Surface Runoff - 1094 cf% of Total Rainfall VolumePre Development Fates
Post Filtration Outflow - 0 cf Other
Infiltration by BMPs - 1312 cf Permeable Pavement Infiltration - 0 cf
Disconnected Impervious Infiltration - 0 cf Green Roof Evapotranspiration - 0 cf
Infiltration and ET - 35237 cf
FATE OF RAINFALL GRAPHS
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TIME OF CONCENTRATION CALCULATIONS:
Pre-Development
Length (ft) Slope (ft/ft)Tt (hrs)
85 0.03 0.17
125 0.05 0.01
Length (ft) Slope (ft/ft) n-value
Flow Area
(ft2)Tt (hrs)
Channel Flow:
Channel Flow:
Pre-development Tc =10.98 min (Minimum 5 minutes)
Post Development
Length (ft) Slope (ft/ft)Tt (hrs)
85 0.03 0.17
125 0.05 0.01
Length (ft) Slope (ft/ft) n-value
Flow Area
(ft2)Tt (hrs)
Channel Flow:
Channel Flow:
Post-development Tc =10.98 min (Minimum 5 minutes)
ADJUSTED CURVE NUMBER CALCULATIONS:
Pre-Development
F.F. P90 P95 1-Yr 2-Yr 10-Yr 25-Yr 50-Yr 100-Yr
Rainfall (in) = 1.00 1.40 1.86 2.78 3.36 4.89 5.80 6.53 7.27
Q*(in) =0.02 0.03 0.05 0.52 0.88 1.94 2.63 3.21 3.81
CNadj =73 67 61 68 69 70 70 70 70
Post Development
F.F. P90 P95 1-Yr 2-Yr 10-Yr 25-Yr 50-Yr 100-Yr
Rainfall (in) = 1.00 1.40 1.86 2.78 3.36 4.89 5.80 6.53 7.27
Q*(in) =0.02 0.03 0.05 0.12 0.18 0.36 0.50 0.61 0.97
CNadj =73 67 61 54 51 44 41 39 40
PEAK FLOW CALCULATIONS:
F.F.P90 P95 1-Yr 2-Yr 10-Yr 25-Yr 50-Yr 100-Yr
Pre-Development
Q* (in) 0.02 0.03 0.05 0.52 0.88 1.94 2.63 3.21 3.81
qu (csm/in)284.56 284.56 284.56 536.42 607.53 743.97 743.97 743.97 743.97
Q (cfs)0.09 0.13 0.24 4.39 8.32 22.47 30.50 37.24 44.27
Post Development
Q* (in) 0.02 0.03 0.05 0.12 0.18 0.36 0.50 0.61 0.97
qu (csm/in)284.56 284.56 284.56 284.56 284.56 284.56 284.56 284.56 454.27
Q (cfs) 0.09 0.13 0.22 0.52 0.78 1.62 2.20 2.70 6.85
0.0%0.0%-8.3%-88.2%-90.6%-92.8%-92.8%-92.7%-84.5%
Analysis Area = 9.99 Acres (0.016 sq. miles)
Sheet Flow:
Shallow Flow:
Sheet Flow:
Shallow Flow:
Unpaved
Wetted Perimeter (ft)
Sheet Flow:
Shallow Flow:
Wetted Perimeter (ft)
Sheet Flow: Grass
Surface Cover
Analysis Area = 9.99 Acres (0.016 sq. miles)
A PROPOSED EXPANSION FOR KEWAUNEE SCIENTIFIC
STATESVILLE, NC IREDELL County
Shallow Flow:
Drainage Area #
Surface Cover
Grass
Unpaved
Yadkin River Basin
ADDITIONAL CALCULATIONS
STORM-EZ
Version 1.4 Peak Flow Calcs
9/6/2018
Page 11 of 17
**Note: To decrease Post-development peak flows - increase storage volume being drawdown or infiltrated or lengthen post-
development time of concentration. See LID HELP for more information.
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9/6/2018
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STORM-EZ
Version 1.4 O&M Manual
9/6/2018
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-
-
-
-
-
Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately.
The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the vegetated filter if
one is provided.
Wet Detention Pond Maintenance Requirements
Important maintenance procedures:
Immediately after the wet detention basin is established, the plants on the vegetated shelf and perimeter of the
basin should be watered twice weekly if needed, until the plants become established (commonly six weeks).
The vegetated shelf Best professional practices
show that pruning is needed
to maintain optimal plant
health.
Prune according to best professional practices
Plants are dead, diseased or
dying.
Determine the source of the problem: soils, hydrology, disease, etc.
Remedy the problem and replace plants. Provide a one-time fertilizer
application to establish the ground cover if a soil test indicates it is
necessary.
Weeds are present. Remove the weeds, preferably by hand. If pesticide is used, wipe it
on the plants rather than spraying.
The forebay Sediment has accumulated to
a depth greater than the
original design depth for
sediment storage.
Search for the source of the sediment and remedy the problem if
possible. Remove the sediment and dispose of it in a location where it
will not cause impacts to streams or the BMP.
Erosion has occurred.Provide additional erosion protection such as reinforced turf matting or
riprap if needed to prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by hand. If pesticide is used, wipe it
on the plants rather than spraying.
The inlet device The pipe is clogged. Unclog the pipe. Dispose of the sediment off-site.
The pipe is cracked or
otherwise damaged.
Replace the pipe.
Erosion is occurring in the
swale.
Regrade the swale if necessary to smooth it over and provide erosion
control devices such as reinforced turf matting or riprap to avoid future
problems with erosion.
Stone verge is clogged or
covered in sediment (if
applicable).
Remove sediment and replace with clean stone.
If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the
emergency drain should be minimized to the maximum extent practical.
How I will remediate the problem:
The perimeter of the BMP Areas of bare soil and/or
erosive gullies have formed.
Regrade the soil if necessary to remove the gully, and then plant a
ground cover and water until it is established. Provide lime and a one-
time fertilizer application.
Vegetation is too short or too
long.
Maintain vegetation at a height of approximately six inches.
No portion of the wet detention pond should be fertilized after the first initial fertilization that is required to
establish the plants on the vegetated shelf.
Stable groundcover should be maintained in the drainage area to reduce the sediment load to the wet detention
basin.
Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and within 24 hours after every storm event
greater than 1.0 inches (or 1.5 inches if in a Coastal County). Records of operation and maintenance should be kept in a
known set location and must be available upon request.
BMP element: Potential problem:
The entire BMP Trash/debris is present. Remove the trash/debris.
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The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not
readily penetrate into accumulated sediments.
The outlet device Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
An annual inspection by an
appropriate professional
shows that the embankment
needs repair. (if applicable)
Make all needed repairs.
The main treatment area
The receiving water Erosion or other signs of
damage have occurred at the
outlet.
Contact the local NC Department of Environment and Natural
Resources Regional Office.
The embankment Shrubs have started to grow
on the embankment.
Remove shrubs immediately.
Evidence of muskrat or
beaver activity is present.
Use traps to remove muskrats and consult a professional to remove
beavers.
A tree has started to grow on
the embankment.
Consult a dam safety specialist to remove the tree.
Sediment has accumulated to
a depth greater than the
original design sediment
storage depth.
Search for the source of the sediment and remedy the problem if
possible. Remove the sediment and dispose of it in a location where it
will not cause impacts to streams or the BMP.
Algal growth covers over 50%
of the area.
Consult a professional to remove and control the algal growth.
Cattails, phragmites or other
invasive plants cover 50% of
the basin surface.
Remove the plants by wiping them with pesticide (do not spray).
Wet Detention Pond Maintenance Requirements (Continued)
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951.5 951.5
956.75 956.75
1' 1'
949 949
Yes 948 948
Sediment Storage El:
Bottom El: Bottom El:
Has Veg. Filter?
Pretreatment other
than forebay?No
Sediment Storage El:
Clean out depth:
Normal Pool El. Proposed Pond 1
Temporary Pool El:
Wet Detention Pond Design Summary
Normal Pool El.
Clean out depth:
WET POND ID FOREBAY MAIN POND
Temporary Pool El:
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Version 1.4 O&M Manual
9/6/2018
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