20050688 Ver 2_Stormwater Info_20070123

Stormwater Impact Analysis and Minimization
Evaluation 6 a a
UT to Bo d's Creek 2 ° 0 5 V ~
~ Y
Alamance County, North Carolina
Project ID No. 030602,16-16, C, NSW
Prepared for:
t,,
Martin Marietta Materials
Jti.=,'s
2700 Wycliff Road, Suite 104
Raleigh, North Carolina 27607 ~ ~~~~~
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Re-submitted: January 23, 2007
~.
~~~ Kimley-Hom '~,
~ and Associates, Inc,
©Kimley-Horn and Associates, Inc. 2007
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~~~ ~ ~, ~.

~ Kimley-Horn
~ and Associates, Inc.
January 22, 2007 0 ~~~~~~ D
Mr. Ian McMillan ~~N ~+ ~ ~~~7
NCDENR
Division of Water Quality '~
1650 Mail Service Center ~~~~
Raleigh, NC 27699-1650
Subject: Martin Marietta: East Alamance Quarry Expansion
UT to Boyd's Creek [030602, 16-16, C, NSW]
Dear Mr. Ian McMillan:
We are writing in response to the review comments made on December 21, 2006 for
the above referenced project. A list of your comments and our responses are as
follows:
Comments and Responses
^
P.O. Box 33068
Raleigh, North Carolina
27636-3068
1. Please contact the DWQ to schedule intermittent/perennial stream determinations
at the site.
Concur. An intermittent/perennial stream determination will be scheduled with the
DWQ.
2. Please specify the percent of project imperviousness area and provide an inventory
of all impervious surfaces.
The purpose of the subject project is to provide necessary expansion of the hard rock
quarry operation. The amount of imperviousness will increase by approximately 25 acres.
However, this imperviousness will be contained within the quarry pit and stormwater
runoff collected during rainfall events will be utilized as quarry processing water. Any
excess water not utilized for the quarry's processes will be discharged consistent with the
quarry's existing NPDES mine dewatering permit.
Please keep in mind that the dry pond and level spreader BMPs located along the western
boundary of the project are not intended for stormwater treatment as it pertains to
development, but rather are devices that are intended to provide hydration to the wetland
system below. There is no increase in imperviousness to the contributing drainage area
that is being conveyed to this wetland system. The contributing drainage area is located
offsite, and will remain in its existing condition. A majority of existing offsite
stormwater flow that currently runs through the quarry pit expansion area will be rerouted
around the future quarry pit expansion area, and into the wetland system B to the
southwest.
^
TEL [phone]
FAX [phone]

~ ^ Kimley-Horn
~ and Associates, Inc.
3. You indicated during our field meeting that bridging the perennial stream you are
proposing to culvert would not be feasible due to the weight of the haul trucks.
Please provide documentation supporting this assertion or alternative avoidance
and minimization for this crossing.
The loaded trucks that will be hauling material and utilizing the stream crossing will
weigh approximately 219,000 pounds compared to an Interstate highway design load of
80,000 pounds. It is clear that a reinforced concrete pipe crossing will be significantly
less expensive than constructing a concrete bridge system. The cost of such a structure
including girders (five to six feet deep), decking, end bents on piers and approach slabs
will be extremely expensive and is not justifiable for the crossing of interest.
4. The DWQ recommends utilization of the new level spreader guidelines for your
proposed level spreaders.
The level spreader design has been updated per the NC DWQ Level Spreader Design
Guidelines Final Version, Effective Date January 1, 2007. The design of the level
spreader is in accordance with the "Dry Detention Basin followed by Level Spreader"
option. The level spreader has been designed to be built on a maximum slope of 6% with
a 50-foot forested buffer with little to no ground cover. The level spreader will receive a
maximum of 1.63 cfs from a 5" PVC pipe, and will be 106 feet in length. For additional
information please refer to the attached level spreader calculations.
5. In regard to your stormwater plan, please specifically compute drawdown time,
stating "a few days" is not specific enough.
The "Stormwater Impact Analysis and Minimization Evaluation Memorandum" has been
edited to reflect the calculated drawdown time of 3.8 days for the temporary storage
volume (1"storm) through the 2-inch low flow orifice.
6. Please submit 401 BMP worksheets
Concur. The 401 BMP worksheets for the Dry Pond and Level Spreader have been
included. The BMPs have been designed per DWQ guidelines to ensure proper function.
Points B, C, and D which are summarized in your table within section, "Water
Quantity Calcs." Of your Stormwater Impact Analysis need to be shown on plan
sheets, not simply shown on marked-up topographic maps.
Points A, B, C, D, and E have been added to the "Overall Site Plan" sheet in the
Stormwater Plan. Drainage areas are not displayed within the "Stormwater Plan" due to
the size of the drainage areas compared to the available contour area.
8. Please re-submit your stormwater plan sheets at a scale of no smaller than 1"=50'.
The plan sheets have been adjusted to a Full-Size set with scales no smaller than 1"=50'
per your request.

^ ~ ^ Kimley-Horn
~ and Associates, Inc.
As requested, the following are enclosed to accompany this re-submittal:
^ Five (5) revised sets of Stormwater Plans;
^ Five (5) copies of the 401 BMP worksheets with copies of the Operation
and Maintenance Agreements (located within Stormwater Impact
Analysis);
^ One (1) copy of the original Operation and Maintenance Agreements
attached to this letter; and,
^ Five (5) revised copies of Stormwater Impact Analysis.
We trust this meets your needs at this time. Please feel free to contact me at [phone]
with any questions or concerns.
Sincerely,
KIMLEY-HORN AND ASSOCIATES, INC.
---~
_ __. _
i r.-.
Ryan T. Lewis, E.I.
Enclosures
T:\pn\011185028 MMM EAlamance\DWQ Response Letter 01-22-07.doc

DRY DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT
MARTIN MARIETTA MATERIALS
EAST ALAMANCE QUARRY
ALAMANCE COUNTY, NORTH CAROLINA
The dry detention basin system is defined as the dry detention basin, pretreatment including step pools
and the vegetated filter if one is provided.
Maintenance activities shall be performed as follows:
After every significant runoffproducing rainfall event and at least monthly:
a. Inspect the dry detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool
occurs within 2 to 5 days as designed.
2. Repair eroded areas immediately, re-seed as necessary to maintain good vegetative cover, mow
vegetative cover to maintain a maximum height of six inches, and remove trash as needed.
3. Inspect and repair the collection system (i.e. manholes, piping, swales, riprap, etc.) quarterly to
maintain proper functioning.
4. Remove accumulated sediment from the dry detention basin system semi-annually or when depth is
reduced to 75% of the original design depth (see diagram below). Removed sediment shall be
disposed of in an appropriate manner and shall be handled in a manner that will not adversely
impact water quality (i.e. stockpiling near a detention basin, wetland, or stream, etc.).
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.
When the pool depth from the top of the pond to the top of the sediment deposit reads 3.32 feet in
the main pond, the sediment shall be removed. (See diagram below for associated elevations)
DRY DETENTION BASIN DIAGRAM
TOP OF BANK = 590.00 FT
DEPTH = 3.32 FT ~ 75%
SEDIMENT REMOVAL ELEVATION = 586.68 FT
------------------ ----
BOTTOM ELEVATION = 585.00 FT
5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface.
These plants shall be encouraged to grow along the vegetated shelf and forebay berm.
Page 1 of 2

6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment
through the emergency drain shall be minimised to the maximum extent practical.
7. All components of the dry detention basin system shall be maintained in good working order.
8. Level spreaders or other structures that provide diffuse flow shall be maintained every six months.
All accumulated sediment and debris shall be removed from the structure, and a level elevation shall
be maintained across the entire flow spreading structure. Any down gradient erosion must be
repaired and/or replanted as necessary.
I acknowledge and agree by my signature below that I am responsible for the performance of the seven
maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior
to any changes to the system or responsible party.
Pr1Tlt name: Daniel G. Shephard
Executive Vice President
Arjrlracc• PO Box 30013, Raleigh, NC 27622-0013
Phone:
Signati
Date:
~aiiuary LL, ~vu i
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I Sarah M. LeCompte
North Carolina , County of Wake
Daniel G. Shephard
a Notary Public for the State of
do hereby certify that
personally appeared before me this 22 day of
January , 2007 ,and acknowledge the due execution of the forgoing dry detention basin
maintenance requirements. Witness my hand and official seal,
SEAL
My commission expires August 3, zoos
SGCah 'M ~ Le ~s (re~-2
Page 2 of 2

LEVEL SPREADER OPERATION AND MAINTENANCE AGREEMENT
MARTIN MARIETTA MATERIALS
EAST ALAMANCE QUARRY
ALAMANCE COUNTY, NORTH CAROLINA
The level spreader is defined as an elongated, level threshold, designed to diffuse stormwater
runoff.
Maintenance activities shall be performed as follows:
1. After construction and until vegetation has been established, level spreader shall be
inspected after every rainfall. Thereafter, level spreader shall be inspected at least every
month and more frequently during the fall season and after heavy rainfall events:
a. Accumulated sediment, leaves, and trash shall be removed, and repairs made if
required.
b. Inspect level spreader for evidence of scour, undercutting, settlement of the structure,
and concentrated flows downhill from the level spreader.
c. A level elevation shall be maintained across the entire flow-spreading structure at all
times. Repair or replace the level spreader if it is damaged.
d. Mow vegetative cover to a height of six (6) inches and prune plants if they cover over
half of the level spreader surface.
e. Repair eroded areas and replace/replant dead or damaged vegetation.
2. The contractor should avoid the placement of any material on and prevent construction
traffic across the structure. If the measure is damaged by construction traffic, it shall be
repaired immediately.
3. Inspect and repair the collection system (e.g., riser structure, manholes, pipes, swales,
riprap) four (4) times a year to maintain proper functioning.

I acknowledge and agree by my signature below that I am responsible for the performance of the
maintenance procedures listed above. I agree to notify DWQ of any problems with the system or
prior to any changes to the system or responsible party.
Prlnt name: Daniel G. Shephard
Tltle: Executive Vice President

Addre~~•
Phone
S ignat
Date:
I Sarah M. LeCompte , a Notary Public for the State of
North Carolina ,County Of wake , do hereby certify that
Daniel G. Shephard personally appeared before me this 22 day of
January ~ 2007 ,and acknowledge the due execution of the forgoing bioretention
area maintenance requirements. Witness my hand and officpial,seal,
~~~~h M ~ L~ ~ e
SEAL
My commission expires August 3, zooa
PO Box 30013, Raleigh, NC 27622-0013

i ^ ~ ~ Kimley-Horn
~ _ and Associates, Inc.
M e m o r a n d u m
Date: January 2007
Project: Martin Marietta Materials: East Alamance Quarry
Alamance County, North Carolina
Subject: Stormwater Impact Analysis and Minimization Evaluation for the expansion area
adjacent to the mine in support of Section 404/401 permitting.
OVERVIEW
This memorandum provides a limited Stormwater Impact Analysis and Minimization Evaluation
conducted for the proposed East Alamance Quarry expansion located in Alamance County, North
Carolina. It is intended that this analysis would be attached to the 401 water quality certification
• application for review by the NC Division of Water Quality (NCDWQ).
The East Alamance Quarry is located to the south of SR 1752 and west of NC State Highway 49,
northeast of Burlington, NC. The site is also located northeast of the Haw River and contains a portion
of Boyd's Creek, a tributary to the Haw River. For the expansion area within the quarry site, Boyd's
Creek serves as the eastern boundary. The site is primarily forested with some agricultural fields in the
northwest corner of the expansion area. A 90 foot wide power line corridor extends across the expansion
area from west to east. The 404/401 Permit Figures 1 through 3 (attached) show the expansion tract
permit area and referenced areas below.
Currently five streams and five wetlands have been identified within the subject property. Stream A
originates from Wetland A, near the northern boundary and flows southeast to Boyd's Creek located
along the southeastern boundary. Stream A is conveyed through culverts in two locations for distances
of approximately 437 and 104 feet. The total length of Stream A within the property is approximately
3,487 linear feet. Stream B is located in the southwestern corner of the property, entering south of the
power line, and flows southeast to the southern boundary of the property. The total length of Stream B
within the property is 1,746 linear feet. Stream C originates from Wetland B, within the property,
immediately south of the power line and flows southwest into Stream B just outside of the properly
boundary. The total length of Stream C within the property is 457 linear feet. Stream D originates south
of the power line, and flows southwest into Stream B near the western boundary of the property. The
total length of Stream D within the property is approximately 6941inear feet.
The proposed pit expansion project will directly impact Wetland A and Stream A from the pit expansion
and perimeter berm construction, and Boyd's Creek for an additional stream crossing for haul trucks into
the expanded pit area. A Mine Plan is included with the permit documentation, however, Figure 3 shows

Martin Marietta Materials
East Alan:ance Q~~arry
Stonnwater Impact Analysis antl Minimization
the approximate limit of the expanded pit north of the power line, and the berm would typically be north
and west of the expanded pit.
Since portions of the watersheds for Stream A and WetlandB/Stream C will be removed by expansion of
the mine, measures proposed for these areas are discussed below to avoid secondary impacts to receiving
waters while mining activities continue on the site. Also, the additional Boyd's Creek road crossing
design is discussed below.
Wetland B/Stream C
The proposed quarry expansion will expand along the eastern edge of Wetland B, removing a portion of
the existing drainage area flowing to this wetland stream system. To offset potential impacts associated
with the removal of a portion of the watershed, the proposed design is intended to provide supplementary
hydrology to Wetland B and Stream C. This will be accomplished by diverting flows from the off-site
farm pond into Wetland B. This diversion of stormwater will provide two benefits; it will supplement
the hydrology of Wetland B/Stream C to the south, as well as, divert the stormwater discharge from the
farm pond away from the quarry expansion area.
An evaluation ofpre-development vs. post-development hydrology of the Wetland B system and farm
pond was performed. The purpose was to determine the amount of stormwater discharge Wetland
• B/Stream C were receiving in predevelopment conditions, and evaluate post-development hydrology.
The 2-year, 24-hour storm event was chosen for the analysis because its frequency and resultant
discharge is close to the effective channel forming discharge.
In order to provide this supplemented hydrology, a new 36" CMP riser will be installed into the existing
farm pond to divert the excess stormwater. All existing structures within the farm pond will remain in
place, and the base flow that currently is released from the farm pond would be unaffected. The base
flow will continue to discharge from the existing 4" PVC riser, and a new 36" CMP riser will be set at
approximately 5.0 inches above the existing riser in the farm pond. This will allow the farm pond to
continue to recharge its volume, and continue to be used for irrigation purposes. It is estimated that the
36" CMP riser will begin to discharge during storm flows greater than 1.2 CFS. This flow will be
diverted through a 24" CMP culvert along the western edge of the site at an average slope of
approximately 0.7% (see Plan Sheet 1). This diversion will require approximately 1,300 linear feet of
24" CMP and 3 junction boxes, and a headwall to daylight the pipe. The 24" pipe system will then flow
through a trapezoidal grassed-lined channel to a dry detention pond located just west of Wetland B. The
dry detention pond will provide detention to reduce the post-development 2-year, 24-hour peak discharge
to apre-development level.
The dry pond will require a 18" CMP riser that will outfall to a level spreader through a 5" PVC pipe,
and will bypass larger flows through a 15" CMP that directly outfalls to Wetland B. The level spreader,
designed according to the North Carolina Division of Water Quality's "Level Spreader Design
Guidelines, Final Version, Effective Date January 1, 2007", will receive a maximum flow of 1.63 cfs
from the 5" PVC when the dry pond is full and will be required to be 106 feet in length. This is in
accordance with the "Dry Detention Basin followed by Level Spreader" option. The level spreader has
• been designed to be built on a maximum slope of 6% with a 50-foot forested buffer with little to no
ground cover. The majority of stormwater flowing to the level spreader will flow through a 2.0-inch low
2

Martin Marietta Materials
East Alamance Quarry
Stonnwater bnpact Analysis and Minimization
flow orifice before reaching the 5" PVC pipe. The low flow orifice will provide slow release of the
temporary storage volume detained under elevation 585.46 through the level spreader over a period of 3.8
days. This design will provide extended hydration and diffused flow to Wetland B/Stream C. Please
refer to the dry detention and level spreader calculations contained in the "Water Quantity" section, and
the 401 BMP worksheets found in the "401 BMP Worksheet" section of this report.
The pre-development 2-year, 24-hour storm event at Wetland B/Stream C has a discharge of
approximately 4.22 cfs, and the post-development 2-year, 24-hour storm event will have a discharge of
approximately 4.83 cfs. This will provide an increase of 14.45% between pre- and post- development
conditions. Please refer to the "Water Quantity", "Pre-development Stormwater Calculations", and
"Post-development Stormwater Calculations" sections of this report for more information regarding the
pre vs. post analysis.
Stream A Pumping Strategy
The expansion of the pit will remove contributing drainage area during active mine operations to Stream
A. To reduce this hydrologic impact, water is proposed to be diverted or pumped from Boyd's Creek
into the remaining 1,000 linear foot section of Stream A as a temporary measure until the area upslope
of the avoided segment of Stream A is developed for the mine expansion. Stream A is an intermittent
stream, so the intent is to provide supplemental periodic storm flow to the stream in addition to the
• watershed area to remain. Once this area of the mine is expanded, a modification to the mine's NPDES
permit will be requested to allow for a discharge to Stream A.
To accomplish this goal, a pumping station will be located between Boyd's Creek and Stream A. This
pumping station will be designed to convey the pre-development base flow of the Stream. The pre-
developmentbase flow for Stream A has been calculated to be approximately 0.54 cfs, which equates to
approximately 220 gallons/minute. Please refer to the "Water Quantity" section of this report for the
"Pump Sizing for the Unnamed Tributary". The pump will be automated by the water level within
Boyd's Creek. The pump will be set to turn on via a float gage when the water level in Boyd's Creek
reaches a field determined elevation, typically, 0.1 to 0.2 feet above mean base flow. The pump will be
set to turn off when Boyd's Creek recedes back towards base flow elevation. These elevations will need
to be determined in the field by an engineer once the final location of the pump has been determined.
The pump intake hose will be located in a deep pool within Boyd's Creek and will include a sediment
screen to protect the pump from sediment. The water will be conveyed through approximately 3041inear
feet of 4" ductile iron pipe located below the ground surface approximately 3 feet. The water will be
pumped approximately 22 feet in elevation, where the water will then flow downhill to Stream A at the
limit of the proposed pit expansion. Plan Sheet 2 shows the proposed design.
Road Crossin o~yd's Creek
In order to access the expanded pit, the proposed expansion will require an additional haul road crossing
• over Boyd's Creek, impacting of 98 feet of the stream. The design of the proposed crossing will closely
resemble the existing upstream haul road crossing. The crossing will require 581inear feet of dual 84"

Martini Marietta Materials
East Alantmice Quarry
Storrnwater Gnpact Aiia[ysis artd Minimization
corrugated metal pipes, buried to a 1 foot depth within Boyd's Creek. This design will not allow the 10-
year, 24-hour storm, to over-top the road, but does allow overtopping for the 100-year, 24-hour storm
event. The 100-year, 24-hour storm event has been designed to overtop the road to reduce the possibility
of failure within the embankment, and to comply with "no rise" requirements for the 100-year floodplain.
Plan Sheet 3 shows the proposed crossing design.
MPthnc~c
The proposed stormwater management facilities were sized using methods prescribed by the
aforementioned resources. The stormwater analysis was routed using "Pond Pack," a Haested Methods
computer software program that utilizes TR-55 methods of calculating time of concentration and SCS
methods of generating hydrographs.
Pipes were sized using "FlowMaster" a Haested Methods computer software program that utilizes the
Manning's equation for calculating pipe flow data.
The culverts for the road crossing were analyzed using "Culvert Master" a Bentley Inc. computer
software program that utilizes Manning's equation, weir equation, and the orifice equation for a designed
crossing to calculate flow, and water elevations for the crossing. Flow data was determined using the
National Flood Frequency Program computer program for the Blue Ridge/Piedmont Region of North
. Carolina based on the drainage area of Boyd's Creek at the road crossing.
Conclusion
Based on the analyses provided herein, the proposed system will be adequate to address the stormwater
requirements of the North Carolina Department of Environment and Natural Resources (NCDENR).
Attachments
• 404/401 Permit Figures:
Figure 1: Vicinity Map
Figure 2: USGS Topographic Map
Figure 3: Aerial Photograph and Jurisdictional Features Map
• Stormwater Analysis Figures:
Figure 1: Pre-Development Drainage Map
Figure 2: Post Development Drainage Map
• 401 BMP Worksheets:
401 Extended Dry Detention Basin Worksheet
401 Level Spreader Worksheet (1/2007)
• Water Quantity Calculations
• Pre-Development Stormwater Calculations
• Post-Development Stormwater Calculations
• Appendices
•
4

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Project East Alamance Quarry
Alamance County, North Carolina
Marlin Marietta /Mloriels /\ /~
v~ Date Project Number Figure
11/6/2006 011185024 2

T:\pn\011185024 E. Alamance\404 Permit\404_figures.doc Prepared by Chad Evenhouse [~~~ ~~1«,Irc.

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_ "~ °` ~ { ~ ~~ k:,~ ,, ~ Expansion Study Area
~, s ~ ~, , Proposed Mine Expansion Limits
~.'~~' ^k'~a~.~7+' ~ ~ Wetlands
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~ -°~-~- Boyd's Creek (Source:NCDWO)
~ Stream lengths and wetland areas are based on
the Jurisdictional Areas survey, signed by the ',.r Culvert
_ _ USACE on July 6, 2006.
0 250 5(:)t. Stream (GPS Surveyed)
~ - 2005 black and white aerial from Martin Marietta Materials ~ Stream Importantance Call
Feet 1998 color infrared aerial from NCDOT
y ,
Title Aerial Photograph and Jurisdictional Features Map

w..~m wren. LLU.falc
^n Project East Alamance Quarry
~ v" Date Project Number Figure
11/6/2006 011185024 3

T:\pn\011185024 E. Alamance\404 Permit\404_figures.doc Prepared by Chad Evenhouse [~~ ~,,,~

F'RE-DEVELOPMENT DRAINAGE AREAS
SQ. MI ACRES
DRAINAGEA AREA A 0.098 63
DRAINAGEA AREA B 0.022 14
DRAINAGEA AREA C 0.180 115
DI~AINAGEA AREA D 0.413 264
DRAINAGEA AREA E 3.236 2071
DRAINAGEA AREA F 4.297 2750
2ao5o s8s
vZ
2000
GRAPHIC SCALE
4G00 aooo
8000
( IN FEET )
1 inch = 2000ft.
Kimley-Horn u MAMATERIALSTTA
~~~ ~ a~ ~m ~n ~ and Associates, Inc, ,,,~ ~-
°~~"~ .A~ a~ ~-~~-~~~"'°" P,a,~OX_{~~~~~ PRE-DEVELOPMENT DRAINAGE MAP
gx.Ni.n as /rodep,, ~ r,a a wb-t wt~ ~o ~+•rwa~ as roda., ~
arM~ -.e ~.oa.a. ~. mos PF10PCt ~9N) d77~100G FAX (9N) QT1~l000
EAST ALAMANCE QUARRY
ALAMANCE COUNTY, NORTH CAROLINA
nwm immrc na au Mroe aar x.,Q
011185044 FIGURE t

,000
4000
POST-DEVELOPMENT DRAINAGE AREAS
SQ. MI ACRES
DRAINAGEAAREAA 0,098 63
DRAINAGEAAREAB 0.007 5
DRAINAGEA AREA C 0.119 76
DRAINAGEA AREA D 0.397 254
DRAINAGEA AREA E 3.236 2071
DRAINAGEA AREA F 4.297 2750
GRAPHIC SCALE
500 1000 2000
( IN FEET )
1 inch = 1000 ft.
ra~rulm w nE ama v:
~ Kimley-Horn
~ and Associates, I nc.
MARTIN MARIETTA - PRO~E~T.
MATERIALS EAST ALAMANCE QUARRY
~~
ALAMANCE COUNTY, NORTH CAROLINA
Rn
POST-DEVELOPMENT DRAINAGE MAP °"° Rn ~R,,~,~,~,~ A~ ~,.~
Sul: CWE 011185024 FIGURE2

Project No. DWQ
• DIVISION OF WATER QUALITY
401 EXTENDED DRY DETENTION BASIN WORKSHEET
DWQ Stormwater Management Plan Review:
At a minimum, a complete Stormwater management plan submittal includes a worksheet for each BMP, design calculations, plans and
specifications showing all BMPs and outlet structure details, a detailed drainage plan and a fully executed operation and maintenance
agreement. An incomplete submittal package will result in a request for additional information and will substantially delay final review and
approval of the project
PROJECT INFORMATION (please complete the following information):
Project Name
Contact Person:
Phone Number:
For projects with multiple basins, specify which basin this worksheet applies to:_
Drainage Area: f~acres Percent Impervious Area: y PP % E-- ~-u. Exts'r•i nl~ ~ nio P~~~Ea 1~/C.d.E~lf E
II. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices Manual (N.C. Department of
Environment, Health and Natural Resources, November 1995) and Administrative Code Section: 15 A NCAC 2H .1008. Initial in the space
provided to indicate the following design requirements have been met and supporting documentation is attached. If a requirement has not
been met, attach an explanation of why.
Applicants Initials
Either capture runoff from 1 yr., 24 hour storm and release over a 48 hour period, or (l ~~ 5-ra~[M ~ 3 • p' DAIS }
• (ZTL capture runoff from 1 inch storm and draw down over a period of 2 to 5 days.
Please provide routing for 1 yr. 24 hr. event or volume from 1 inch rain
-2-s1. The basin length to width ratio is greater than 3;1. (2 = t --~ (.in~~"rED 0`f Lockttoa of
~Tt_ The basin side slopes are no steeper than 3:1.
,2-R A small permanent pool at outlet orifice is provided to reduce clogging.
Q~TI.. An emergency drain to completely empty the basin is provided.
rLtt.. Vegetation plan prepared is specified on plans.
~2xt Basin to be stabilized within 14 days of construction is specified.
t.Tt- Sediment storage (20% of detention volume) in addition to detention volume is provided.
wE-r~n..+~ i Pd.ePrsrY riowa~..
~Yt. Inlet and outlet erosion control measures to prevent scour are provided.
YL'T L Additional treatment to meet the 85% TSS removal efficiency is provided. C (.EJf ~ SKKE~-n~ ; ~STE~ F«?EK- sTw ~~
KTL Access for clean-out and maintenance is provided.
2Tt. Inlet plunge pool or other energy dissipation is provided. (StEr Pool. tttitu cZV~ E,t'
YL'n.. Forebay is provided to capture sediment and minimize clean-out problems.( s~'EO Pacts Te q.L-~ q-s fac4,,~gR~
Tt_ Uncompacted natural soils are utilized to promote vegetation and reduce sedimentation.
~,.-rt_ Seasonal high water table is at least 1 foot below bottom of basin.
-2T~ If used as a temporary sediment basin, plans indicate clean-out prior to final operation.
~tt_ A site specific operation and maintenance plan with the following provisions is provided. ~ pExr p~~ 1
~.-tt.. The 0&M agreement is signed by the responsible party and notarized. /
?oa~osss
v2

• DRY DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT
MARTIN MARIETTA MATERIALS
EAST ALAMANCE QUARRY
ALAMANCE COUNTY, NORTH CAROLINA
The dry detention basin system is defined as the dry detention basin, pretreatment including step pools
and the vegetated filter if one is provided.
Maintenance activities shall be performed as follows:
1. After every significant runoffproducing rainfall event and at least monthly:
a. Inspect the dry detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice of any obstructions such that drawdown of the temporary pool
occurs within 2 to 5 days as designed.
2. Repair eroded areas immediately, re-seed as necessary to mauitain good vegetative cover, mow
vegetative cover to maintain a maximum height of six inches, and remove trash as needed.
3. Inspect and repair the collection system (i.e. manholes, piping, swales, riprap, etc.) quarterly to
• maintain proper functioning.
4. Remove accumulated sediment from the dry detention basin system semi-annually or when depth is
reduced to 75% of the original design depth (see diagram below). Removed sediment shall be
disposed of in an appropriate manner and shall be handled in a manner that will not adversely
impact water quality (i.e. stockpiling near a detention basin, wetland, or stream, etc.).
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.
When the pool depth from the top of the pond to the top of the sediment deposit reads 3.32 feet vl
the main pond, the sediment shall be removed. (See diagram below for associated elevations)
DRY DETENTION BASIN DIAGRAM
TOP OF BANK = 590.00 FT
DEPTH = 3.32 FT ~ 75%
SEDIMENT REMOVAL ELEVATION = 586.68 FT_
----------------- ----
BOTTOM ELEVATION = 585.00 FT
5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface.
These plants shall be encouraged to grow along the vegetated shelf and forebay berni.
•
Page 1 of 2

• 6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment
through the emergency drain shall be minimised to the maximum extent practical.
7. All components of the dry detention basin system shall be maintained in good working order.
8. Level spreaders or other structures that provide diffuse flow shall be maintained every six months.
All accumulated sediment and debris shall be removed from the structure, and a level elevation shall
be maintained across the entire flow spreading structure. Any down gradient erosion must be
repaired and/or replanted as necessary.
I acknowledge and agree by my signature below that I am responsible for the perforn~ance of the seven
maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior
to any changes to the system or responsible party.
Print name: Daniel G. Shephard
Title: Executive vice President
January 22, 2607
• Note: The legally responsible party should not be a homeowners association unless snore than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I Sarah M. LeCompte
North Carolina
Daniel G. Shephard
County of wake
a Notary Public for the State of
do hereby certify that
personally appeared before me this 22 day of
January ~ zoo7 ,and acknowledge the due execution of the forgoing dry detention basin
maintenance requirements. Witness my hand and official seal,
SEAL
~~~ ~
~G~ah 'M~ L2
My commission expires August 3, 2 0 o s
•
Page 2 of 2
f~(j(jl'P.CC' PO Box 30013, Raleigh, NC 27622-0013

DWO Project No.
• DIVISION OF WATER QUALITY -LEVEL SPREADER WORKSHEET (112007)
I. PROJECT INFORMATION (please complete the folloving information):
Project Name : E.4sr A~ANU-.~cE. Q~nc/at
Contact Person: Q.~~ - • lE~~s Phone Number: (9!9) ,~~~ - y I ~f8~
Level Spreader ID; LVL' DI
Level Spreader Length I Dte ft.
Drainage Area ca 3. v ac.
Impervious Area . v ac.
Forebay Area ~5 ~~. 2y o^'O cu ft.
Maximum Filter Strip/Buffer Slope ~ •v
grass
(perpendicular to flow)
(on-site and off-site drainage to the level spreader)
(on-site and off-site drainage to the level spreader)
(0.2% of the contributing impervious surface area)
(6% for forested, leaf littler cover, 8% for thick ground cover
Max. Discharge from 1 "/Hr Storm /`~~ o cfs
Max. Discharge to Level Spreader /. (0 3 cfs
Filter Strip/ Zone 2 Buffer Vegetation t=e~sr w f LF Af Ll7'r6s (thick ground cover or grass; canopied forest with leaf litter
groundcover)
Pre-treatment or Bypass Method Used 9(ul ~oa0
II. REQUIRED ITEMS CHECKLIST
Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. !f a
requirement has not been met, attach an explanation of why. At a minimum, a complete stormwater management plan submittal includes
• a worksheet for each BMP, design calculations, plans and specifications showing all BMPs and outlet structure details, a detailed
drainage plan and a fully executed operation and maintenance agreement. An incomplete submittal package will result in a request for
additional information and v~ill substantially delay final review and approval of the project.
A~olicants Initials
~'R Project Site was visited prior to designing level spreader.
P~•c~ Date of the Site visit. PLEASE ATTACH TIME-DATED DIGITAL PHOTO OF EXISTING BUFFER CONDITIONS.~Q~E>
RTL Level spreader is at least 13 ft. per cfs for thick ground cover or grass or 65 ft per cfs in canopied forest with leaf
litter for 50-foot buffer; 50 ft per cfs for 100-foot buffer, or 40 ft. per cfs for 150-foot buffer.
KT~- Pre-Formed Scour Holes are on flat slopes only.
tZ~st No structures are located in protected buffers (must meet no practical alternatives criteria).
Design Alternative (if any) and Bypass method used:
12TH.. Bypass conveyance method is specified and plan details and calculations are provided.
R-rt Alternative design option is specified and plan details and calculations are provided.
R~ Discharge to level spreader and subsequent filter strip is hydraulically and spatially separate from the bypass
discharge.
12.'n.. No structures are located in protected buffers.
Ksf~• Plan details .for the bypass and outlets are provided.
1C~ The operation and maintenance agreement includes annual erosion and vegetation repair. Fou.vw~ P~'C~ )
ra--R.. The operation and maintenance agreement signed and notarized by the responsible party is provided~f~

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Photo rag, ph 1: Existing conditions of level spreader (LVL-O1) forested buffer conditions. Standing on utility easement facing north-west. Wetland
located in center of utility easement (photo center), and the forest buffer is located to the north of the wetland. Photo taken May 2, 2006.
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Photograph 2: Existing conditions ol~ level shr~a~lF~r { Lti' L-O I j ~rL~ted butler e e~nditiuns. ~tandillg ot7 uliiity eascmel~t lacul* north. Wetland
located in center of utility easement (photo center), and the forest buffer is located to the north of the wetland. Photo taken May 2, 2006.
Title Level Spreader Buffer Existing Condition
East Alarrance Quarry
Prepared For Project ~ arra nce Count North Carolina
rtin 1V)irietta
1V)i t e r i a l s Date Project Number Page
1/18/07 011185028 1

T:\pn\011185028 1v1~4 EAlamance\Stoimwater Analysis\Buffer Photo page.doc Prepared by Ryan Lewis ~~~ Klmley-Horn
~ and Associates, Inc.

• LEVEL SPREADER OPERATION AND MAINTENANCE AGREEMENT
MARTIN MARIETTA MATERIALS
EAST ALAMANCE QUARRY
ALAMANCE COUNTY, NORTH CAROLINA
The level spreader is defined as an elongated, level threshold, designed to diffuse stormwater
runoff.
Maintenance activities shall be performed as follows:
1. After construction and until vegetation has been established, level spreader shall be
inspected after every rainfall. Thereafter, level spreader shall be inspected at least every
month and more frequently during the fall season and after heavy rainfall events:
a. Accumulated sediment, leaves, and trash shall be removed, and repairs made if
required.
b. Inspect level spreader for evidence of scour, undercutting, settlement of the structure,
and concentrated flows downhill from the level spreader.
c. A level elevation shall be maintained across the entire flow-spreading structure at all
times. Repair or replace the level spreader if it is damaged.
• d. Mow vegetative cover to a height of six (6) inches and prune plants if they cover over
half of the level spreader surface.
e. Repair eroded areas and replace/replant dead or damaged vegetation.
2. The contractor should avoid the placement of any material on and prevent construction
traffic across the structure. If the measure is damaged by construction traffic, it shall be
repaired immediately.
3. Inspect and repair the collection system (e.g., riser structure, manholes, pipes, swales,
riprap) four (4) times a year to maintain proper functioning.
•

• I acknowledge and agree by my signature below that I am responsible for the performance of the
maintenance procedures listed above. I agree to notify DWQ of any problems with the system or
prior to any changes to the system or responsible party.
Prlllt name: Daniel G. Shephard
T']tle: Executive vice President
Address: Po Box 30013, Raleigh, NC 27622-0013
Phone:
S ignat~
Date:
•
I Sarah M. LeCompte
e
a Notary Public for the State of
North Carolina , COUnty Of wake , do hereby certify that
Daniel G. Shephard personally appeared before me this 22 day of
January ~ zoo7 ,and acknowledge the due execution of the forgoing bioretention
area maintenance requirements. Witness my hand and official seal,
ed `'r ~SnF. ~?~~.
r ~ ~~ ~~
_,>.,.'~_ a' c
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'~ ` -
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. ~.~ ~ ~ C~'~~ 'jam
SEAL
My commission expires August 3, zoos

• • •
~ ~ KimleyHorn
\ ~ / and Associates, Inc.
EAST ALAMANCE
STORMWATER ROUTING SUMMARY
1/18/2007
Point of
Analysis Pre-Developed 2-year
Discharge (cfs) Post-Developed 2-year
Discharge (cfs)
Increase
Detention Required
Remarks
B 4.22 4.83 14.45% YES d and w/ level spreader
C 83.91 277.44 230.64% YES Within pit ex ansion area
D 122.92 117.74 -4.21 % NO See re and ost fi ures
Notes:
1. Drainage Areas A, E, and F not included. Drainage Areas unchanged by pit expansion
2. Stormwater draining to analysis point C will be detained within the pit and be subject to the East Alamance Quarry's NPDES permit
~_~
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•
^~^ Kimley-Horn
~ and Associates, Inc.
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Designed by ~T L Date $ ' Z`f ' ~ ~ Checked by Date _
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DRY DETENTION BASIN
Project Information
Project Name
KHA Project #
Designed by
Revised by:
Checked by:
Site Information
Sub Area Location
Drainage Area (DA) _
Impervious Area (IA) _
Percent Impervious (I) _
East Alamance Quarry
011185024
RTL Date: 7/26!2006
RTL Date: 1/4/2007
TWS Date: 1/4/2007
Bypass of Drainage Area A to
Drainage Area B
63 Acres
3.00 Acres
4.8
Required Storage Volume:
Design Storm = 1 inch (Project Does Not Drain to SA waters)
Determine Rv Value = 0.05 + .009 (I) = 0.09 in/in
Storage Volume Required = 21,236 cf
Elevations
Top of Berm Elevation = 590.00 ft
Temporary Pool Elevation = 585.46 ft
Bottom of Pond Elevation = 584.00 ft
Emergency Spillway Elevation = 589.00 ft
Bottom of Forebay = 583.00 ft
Wet Basin AreasNolumes
Area @ Top of Temporary Pool = 15,591 sf
Volume of Temporary Storage = 21,268 cf
Side Slopes of Pond = 3 : 1
Volume of Storage for 1" Storm = 21,268
Orifice Sizing
Forebay Sizing 1
Q2 Days = 0.123 CfS
Os Days = 0.082 Cfs
Orifice Size = 2.00 in
~+ orifice = 0.065 CfS
Drawdown Time = 3.8 days
less than 5 days (yes/no) ? yes
greater than 2 days (yeslno) 7 yes
Bottom of Forebay 1= 583.00 ft
Surface Area of Bottom= 120 sf
Top of Forebay 1 = 585.00 ft
Surface Area of Top = 342 sf
Forebay Depth = 2 ft
Forebay Volume = 462 cf
Anti-Flotation Device
(Elev = 585.46)
(Orifice Elev (584.00) to Emerg. Spillway Elev. (585.46))
Yes ( 21268 > 21236) cf
(Flowrate required fora 2 day drawdown)
(Flowrate required fora 5 day drawdown)
(Diameter)
Riser Diameter: 1.5 ft
Top Riser Elev.: 588 ft
Bottom Riser Elev.: 583 ft
Height of Riser: 5 ft
Area of Riser: 1.8 sf (Water Displaced)
Volume of Riser: 8.8 cf (Water Displaced)
Factor of Safety: 1.3
Weight: 551.3 Ibs
Weight Req'd from Anti-Flotation Device: 716.8 Ibs
Additional Volume of Concrete Req'd: 8.2 cf (Bouyant WT of Concrete = (150-62.4) pcf)
Depth of Anti-flotation: 4.75 ft
Volume Provided: 8.4 cf (Extend 18" riser pipe 4'-9" below invert)

• ~ / \ KimleyHorn
~ and Associates, Inc.
LEVEL SPREADER SUMMARY SHEET
Project Information
Project Name: East Alamance
KHA Project #: 011185024
Designed by: RTL Date: 7/26/2006
Revised by: RTL Date: 1/4/2007
Checked by: TWS Date: 1/4/2007
Level Spreader Design
Runoff 1"Ihour intensity:
t2=CIA
C =Rational Coefficient
Drainage Area = 63.00 ac
I = 1.00 in/hr
C value
Area (acres) C Composite
C
Impervious Area 3 0.95 0.04
Pervious Area 43.4 0.22 0.15
Wooded 16.8 0.10 0.03
Total 0.22
Q1-inch/hr = 14.0 cfs For 63 acre drainage
L~al~ = 908.9 ft * 50' Forested Slope (Q,-;ncn x 65ft/cfs)
• Lmin - 13 ft
Lmax = 130 ft
* Calculated length not within range
*Designed for 5" PVC pipe (Level Spreader Discharge Pipe Calcs)
QM,~ = 1.63 cfs
L~alc = 105.95 ft
* Actual flow from 5" PVC with 5.98 ft of head
* 50' Forested Slope (Q~-;non x 65ft/cfs)
Is Lcelc greater than Lm;n? Yes
Is L~al~ greater than Lmax? Yes
USE: 106 ft
106
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Culvert Sizing.txt
• National Flood Frequency Program
version 3.0
Based on water-Resources Investigations Report 02-4168
Equations from database c:\Program Files\NFF\NFFv3.2_2004-12-14.mdb
updated by kries 9/22/2004 at 4:03:24 PM fixed decimal place in constant
Equations for North_carolina developed using English units
Site: East Alamance, North_Carolina
User: ryan.lewis
Date: Tuesday, August O1, 2006 09:00 AM
Rural Estimate: Boyd's creek culvert
Basin Drainage Area: 3.24 mil
1 Region
Region: Blue_Ridge-Piedmont_Region
Drainage~4rea = 3.24 mil
Crippen & Bue Region 2
Flood Peak Discharges, in cubic feet per second
Recurrence Peak, Standard Equivalent
Estimate Interval, yrs cfs Error, % Years
Boyd's Creek Culvert _~ 2 308 41 2
~Y~ 5 53.E 41 3
sa-v~ µ P~,,_ 10 727 42 4.1
~ 25 1020 44 5.4
~" 50 1270 46 6.4
~-7100 15sn 47 7.2
~o,-yti ~~~ 200 1870 49 7.9
y~a~ 500 2360 52 8.7
F~-~'"' maximum: 12400 (for C&B region 2)
Page 1

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Exhibit 12
Culvert capacity under inlet control
Circular CMP
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190 10.000
166 8,000 EXAMPLE ~~~
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~opyrightH.R Malcom, 2003 [S-13J Exhibits

Culvert Designer/Analyzer Report
Boyd's Creek
• ~ j-~(~.. S~aen~ FvE,J~
Analysis Component
Storm Event S., ./~ Design Discharge 536.00 cfs <<- ~FJ4~ ~ts~~~(--~

Peak Discharge Method: User-Specified
Design Discharge 536.00 cfs Check Discharge 536.00 cfs
Tailwater properties: Irregular Channel
Roughness Segments
Start End Mannings
Station Station Coefficient
0+00 0+75 0.120
0+75 0+87 0.035
0+87 1+02 0.010
1+02 1+09 0.035
1+09 1+93 0.120
Natural Channel Points
Station Elevation
(ft) (ft)
• 0+00 567.00
0+12 560.40
0+35 558.80
0+75 558.50
0+80 557.10
p+87 554.50
0+98 553.40
1+02 557.40
1 +09 557.40
1+18 558.10
1+53 568.50
1+67 570.10
1 +93 579.20
Tailwater conditions for Design Storm.
Discharge 536.00 cfs Actual Depth 2.68 ft
Velocity 17.53 ft/s
Name Description Discharge HW Elev. Velocity
Culvert-1 2-84 inch Circular 535.94 cfs 560.36 ft 10.81 ft/s
Weir Roadway 0.00 cfs 560.36 ft N/A
Total -------- 535.94 cfs 560.36 ft N/A

Title: East Alamance Project Engineer: RTL
t:\...\stormwater analysis\culvert design.cvm CulvertMaster v3.1 [03.01.009.00)
10/10/06 02:26:04C~~ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 3

• Component:Culvert-1
Culvert Summary
Culvert Designer/Analyzer Report
Boyd's Creek
S -`ice STDRn,. ~v~lv~
t+E,4~,~1~~ ft
'~t.51/Prrr o ~
Computed Headwater Elev~ 560.36 ft Discharge 535.94 cfs
Inlet Control HW Elev. 559.98 ft Tailwater Elevation 556.08 ft ~ 'ffFi~w/t'CEA
Outlet Control HW Elev. 560.36 ft Control Type Outlet Control ~~~ k; ~~
Headwater Depth/Height 1.07
Grades
Upstream Invert 552.88 ft Downstream Invert 552.38 ft
Length 60.00 ft Constructed Slope 0.008333 ft/ft
Hydraulic Profile
Profile M2 Depth, Downstream 4.30 ft
Slope Type Mild Normal Depth 4.95 ft
Flow Regime Subcritical Critical Depth 4.30 ft
Velocity Downstream 10.81 ft/s Critical Slope 0.012392 ft/ft
Section
Section Shape Circular Mannings Coefficient 0.024
Section Material CMP Span 7.00 ft
• Section Size
Number Sections 84 inch
2 Rise 7.00 ft

Outlet Control Properties
Outlet Control HW Elev. 560.36 ft Upstream Velocity Head 1.42 ft
Ke 0.90 Entrance Loss 1.28 ft
Inlet Control Properties
Inlet Control HW Elev. 559.98 ft Flow Control Unsubmerged
Inlet Type Projecting Area Full 77.0 ftZ
K 0.03400 HDS 5 Chart 2
M 1.50000 HDS 5 Scale 3
C 0.05530 Equation Form 1
Y 0.54000
•
Title: East Alamance Project Engineer: RTL
t:\...\stormwater analysis\culvert design.cvm CulvertMaster v3.1 [03.01.009.00]
10/10/06 02:26:04C~~ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 2 of 3

Culvert Designer/Analyzer Report
Boyd's Creek

• Component:Weir

Hydraulic Component(s): Roadway
Discharge 0.00 cfs Allowable HW Elevation 560.36 ft
Roadway Width 22.00 ft Overtopping Coefficient 2.50 US
Low Point 563.00 ft Headwater Elevation N/A ft
Discharge Coefficient (Cr) 2.50 Submergence Factor (Kt) 1.00
Tailwater Elevation 556.08 ft
Sta (ft) Elev. (ft)
0.00 566.00
80.00 563.00
110.00 563.00
146.00 566.00
•
•
Title: East Alamance Project Engineer: RTL
t:\...\stormwater analysis\culvert design.cvm CulvertMaster v3.1 [03.01.009.00]
10/10/06 02:26:04C~f9~ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 3 of 3

•
Analysis Component
Culvert Designer/Analyzer Report
Boyd's Creek
Storm Event ~O• ~~ Design Discharge
727.00 cfs t-- QEA~L QISC~AYI-~~
~ o-- `L~ SAM
Peak Discharge Method: User-Specified
Design Discharge 727.00 cfs Check pischarge 727.00 cfs
Tailwater properties: Irregular Channel
Start End Mannings
Station Station Coefficient
0+00 0+75 0.120
0+75 0+87 0.035
p+g7 1+02 0.010
1 +02 1 +09 0.035
1+09 1+g3 0.120
Roughness Segments
Natural Channel Points
Station Elevation
(ft) (ft)
0+00 567.00
• 0+12 560.40
0+35 558.80
0+75 558.50
0+80 557.10
0+87 554.50
0+98 553.40
1+02 557.40
1 +09 557.40
1+18 558.10
1+53 568.50
1 +67 570.10
1+93 579.20
Tailwater conditions for Design Storm.
Discharge 727.00 cfs Actual Depth 2.91 ft
Velocity 20.84 ft/s
Name Description Discharge HW Elev. Velocity
Culvert-1 2-84 inch Circular 727.05 cfs 562.04 ft 12.29 ft/s
Weir Roadway 0.00 cfs 562.04 ft N/A
Total - 727.05 cfs 562.04 ft N/A
•
Title: East Alamance Project Engineer: RTL
t:\...\stormwater analysis\culvert design.cvm CulvertMaster v3.1 [03.01.009.00]
10/10/06 02:25:37C~~ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 3

Culvert Designer/Analyzer Report
Boyd's Creek
• Component:Culvert-1
Culvert Summary (.} ~pwAma,.7t_. ~~JHTr c..~
Computed Headwater Elev~ 562.04 ft Discharge 727.05 cfs
Inlet Control HW Elev. 561.85 ft Tailwater Elevation 556.31 ft ~ TA1L wf)`i ~
Outlet Control HW Elev. 562.04 ft Control Type Outlet Control E LEVA7Z o.-J
Headwater Depth/Height 1.31
Grades
Upstream Invert 552.88 ft Downstream Invert 552.38 ft
Length 60.00 ft Constructed Slope 0.008333 ft/ft

Hydraulic Profile
Profile M2 Depth, Downstream 5.03 ft
Slope Type Mild Normal Depth N/A ft
Flow Regime Subcritical Critical Depth 5.03 ft
Velocity Downstream 12.29 ft/s Critical Slope 0.014752 ft/ft

Section
Section Shape Circular Mannings Coefficient 0.024
Section Material CMP Span 7.00 ft
Section Size 84 inch Rise 7.00 ft
• Number Sections 2

Outlet Control Properties
Outlet Control HW Elev. 562.04 ft Upstream Velocity Head 1.75 ft
Ke 0.90 Entrance Loss 1.57 ft

Inlet Control Properties
Inlet Control HW Elev. 561.85 ft Flow Control Transition
Inlet Type Projecting Area Full 77.0 ftZ
K 0.03400 HDS 5 Chart 2
M 1.50000 HDS 5 Scale 3
C 0.05530 Equation Form 1
Y 0.54000
•
Title: East Alamance Project Engineer: RTL
t:\...\stormwater analysislculvert design.cvm CulvertMaster v3.1 [03.01.OD9.00]
10/10/06 02:25:37®~ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 2 of 3

Culvert Designer/Analyzer Report
Boyd's Creek

. Component:Weir
Hydraulic Component(s): Roadway
Discharge 0.00 cfs Allowable HW Elevation 562.04 ft
Roadway Width 22.00 ft Overtopping Coefficient 2.50 US
Low Point 563.00 ft Headwater Elevation N/A ft
Discharge Coefficient (Cr) 2.50 Submergence Factor (Kt) 1.00
Tailwater Elevation 556.31 ft
Sta (ft) Elev. (ft)
0.00 566.00
80.00 563.00
110.00 563.00
146.00 566.00
•
C7
Title: East Alamance Project Engineer: RTL
t:\...\stormwater analysis\culvert design.cvm CulvertMaster v3.1 [03.01.009.00]
10/10/06 02:25:37C~~ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 3 of 3

Culvert Designer/Analyzer Report
Boyd's Creek
(bc - v1 ~ STb'~e+ l-~~/~wT
• Analysis Component
Storm Event Design Discharge 1,550.00 cfs ~ ~EfttL ~ \S~ ~'~'~ ~
ova -YiG '
[ou - 4.Y~ S
(o~
Peak Discharge Method: User-Specified
Design Discharge 1,550.00 cfs Check Discharge 1,550.00 cfs
Tailwater properties: Irregular Channel
Roughness Segments
Start End Mannings
Station Station Coefficient
0+00 0+75 0.120
0+75 0+87 0.035
0+g7 1+02 0.010
1 +02 1 +09 0.035
1+09 1+93 0.120
Natural Channel Points
Station Elevation
(ft) (ft)
• 0+00 567.00
0+12 560.40
0+35 558.80
0+75 558.50
0+80 557.10
0+87 554.50
0+98 553.40
1 +02 557.40
1+09 557.40
1+18 558.10
1+53 568.50
1+67 570.10
1+93 579.20
Tailwater conditions for Design Storm.
Discharge 1,550.00 cfs Actual Depth 4.98 ft
Velocity 16.21 ft/s
Name Description Discharge HW Elev. Velocity
Culvert-1 2-84 inch Circular 960.02 cfs 565.23 ft 13.67 ft/s
Weir Roadway 589.70 cfs 565.23 ft N/A
Total -------- 1,549.72 cfs 565.23 ft N/A
•
Title: East Alamance Project Engineer: RTL
t:\...\stormwater analysis\culvert design.cvm CulvertMaster v3.1 [03.01.009.00]
10/10/06 02:25:13C~Bt:ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 3

Culvert Designer/Analyzer Report
Boyd's Creek
CO6 - `inL S'l~~lu '~J~T
• Component:Culvert-1
Culvert Summary itF~pu~~~lt- t;L~fi~~n~
Computed Headwater Elev< 565.23 ft Discharge 960.02 cfs
Inlet Control HW Elev. 565.23 ft Tailwater Elevation 558.38 ft c- 'Pf4~t,tlJ F~ 11~1~
Outlet Control HW Elev. 564.50 ft Control Type Inlet Control ~,~s V,pKa ,~
Headwater Depth/Height 1.76
Grades
Upstream Invert 552.88 ft Downstream Invert 552.38 ft
length 60.00 ft Constructed Slope 0.008333 ft/ft
Hydraulic Profile
Profile CompositeM2PressureProfile Depth, Downstream 6.00 ft
Slope Type Mild Normal Depth N/A ft
Flow Regime Subcritical Critical Depth 5.74 ft
Velocity Downstream 13.67 ft/s Critical Slope 0.019232 ft/ft
Section
Section Shape Circular Mannings Coefficient 0.024
Section Material CMP Span 7.00 ft
Section Size 84 inch Rise 7.00 ft
• Number Sections 2
Outlet Control Properties
Outlet Control HW Elev. 564.50 ft Upstream Velocity Head 2.42 ft
Ke 0.90 Entrance Loss 2.18 ft
Inlet Control Properties
Inlet Control HW Elev. 565.23 ft Flow Control Submerged
Inlet Type Projecting Area Full 77.0 ftZ
K 0.03400 HDS 5 Chart 2
M 1.50000 HDS 5 Scale 3
C 0.05530 Equation Form 1
Y 0.54000
•
Title: East Alamance Project Engineer: RTL
t:\...\stormwater analysis\culvert design.cvm CulvertMaster v3.1 [03.01.009.00]
10/10/06 02:25:13C~~ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 2 of 3

Culvert Designer/Analyzer Report
Boyd's Creek

• Component:Weir
Hydraulic Component(s): Roadway
pischarge 589.70 cfs Allowable HW Elevation 565.23 ft
Roadway Width 22.00 ft Overtopping Coefficient 2.92 US
Low Point 563.00 ft Headwater Elevation 565.23 ft
Discharge Coefficient (Cr) 2.92 Submergence Factor (Kt) 1.00
Tailwater Elevation 558.38 ft
Sta (ft) Elev. (ft)
0.00 566.00
80.00 563.00
110.00 563.00
146.00 566.00
•
•
Title: East Alamance Project Engineer: RTL
t:\...\stormwater analysis\culvert design.cvm CulvertMaster v3.1 [03.01.009.00]
10/10/06 02:25:13®Btrntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 3 of 3

~~C~DF.uow PNCB~+r
l~lov~. ,4PP~~"~-
•
`~ Addlink 20 _
Drainage Area B i'OA B
••~''~'~ Addlink 30 _ ~ Ex. Pond Outlet
Drainage Area A Fx. Farm Pond POA A
•
Addlink 40
Drainage Area C POA C
Addlink 50 _
Drainage Area D POA D
26050 688
vz
•

Type.... Master Network Summary _ Page 1.01
Name.... Watershed
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\PREDEVELOPMENT060309BTB.ppw
•
MASTER DESIGN STORM SUMMARY
Network Storm Collection: East Alamance Qu
Total
Depth
Return Event in
Pre 2 3.5000
Pre 10 5.3000
Pre 25 6.0000
Pre 50 6.8000
Pre100 7.6000
Rainfall
Type
----------------
Synthetic Curve
Synthetic Curve
Synthetic Curve
Synthetic Curve
Synthetic Curve
RNF ID
TypeII 24hr
TypeII 24hr
TypeII 24hr
TypeII 24hr
TypeII 24hr
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol Qpeak Qpeak Max WSEL
Node ID Type Event cu.ft Trun min cfs ft
----------
DRAINAGE -----
AREA --
A ----
AREA ----
2
283320
760.02
35.54
DRAINAGE AREA A AREA 10 595425 751.22 78.61
DRAINAGE AREA A AREA 25 727744 751.22 96.95
DRAINAGE AREA A AREA 50 883895 751.22 118.47
DRAINAGE AREA A AREA 100 1094142 751.22 140.41
DRAINAGE AREA B AREA 2 52684 796.92 4.22
DRAINAGE AREA B AREA 10 118185 783.42 10.41
DRAINAGE AREA B AREA 25 146604 783.42 13.10
DRAINAGE AREA B AREA 50 180450 783.92 16.30
DRAINAGE AREA B AREA 100 215452 783.42 19.59
DRAINAGE AREA C AREA 2 471902 738.71 83.91
DRAINAGE AREA C AREA 10 1023602 738.61 194.05
DRAINAGE AREA C AREA 25 1260140 738.61 240.73
DRAINAGE AREA C AREA 50 1540534 738.61 295.63
DRAINAGE AREA C AREA 100 1829350 738.61 351.73
•
Max
Pond Storage
cu.ft
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 2:03 PM 11/10/2006

Type.... Master Network Summary Paqe 1.02
Name.... Watershed
File:... T:\pn\011185024 E. Alamance\Stormwater Analysis\PREDEVELOPMENT060309BTB.ppw
•
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Max
Return HYG Vol Qpeak Qpeak Max WSEL Pond Storage
Node ID Type Event cu.ft Trun min cfs
- ft
-------- cu.ft
------------
----------
DRAINAGE -------
AREA D ----
AREA ------
2 ----------
1134520 -- ---------
766.22 -------
122.92
DRAINAGE AREA D AREA 10 2421732 766.22 278.89
DRAINAGE AREA D AREA 25 2970493 766.22 344.76
DRAINAGE AREA D AREA 50 3619518 766.22 422.12
DRAINAGE AREA D AREA 100 4286777 766.22 501.09
EX. FARM PONDIN POND 2 283320 760.02 35.54
EX. FARM PONDIN POND 10 595425 751.22 78.61
EX. FARM PONDIN POND 25 727744 751.22 96.95
f~
EX. FARM PONDIN POND 50 883895 751.22 118.47 ~a~ s~R
EX. FARM PONDIN POND 100 1044142 751.22 140.41 U~
~ `~ ~~j/.+~
EX. FARM PONDOUT POND 2 13096 1486.53 .81 616.53 / 274333
EX. FARM PONDOUT POND 10 321618 839.72 18.91 616.65 333104
EX. FARM PONDOUT POND 25 453483 814.22 34.14 617.02 364296
EX. FARM PONDOUT POND 50 609180 800.52 53.60 617.20 398570
•
EX. FARM PONDOUT POND 100 769006 785.42 86.98 617.35 425339
*POA A JCT 2 13095 1486.73 .81
*POA A JCT 10 321617 839.72 18.91
*POA A JCT 25 453482 814.22 34.14
*POA A JCT 50 609178 800.52 53.60
*POA A JCT 100 769005 785.42 86.98
*POA B JCT 2 52684 796.92 4.22
~~A~ m
Y+Stwf4iGdr'E-
*POA B JCT 10 118185 783.42 10.41
*POA B JCT 25 146604 783.42 13.10
*POA B JCT 50 180450 783.42 16.30
*POA B JCT 100 215452 783.42 19.59
*POA C JCT 2 471902 738.71 63.91
*POA C JCT 10 1023602 738.61 194.05
*POA C JCT 25 1260140 738.61 290.73
*POA C JCT 50 1540534 738.61 295.63
*POA C JCT 100 1829350 738.61 351.73
•
S/N: F FYXYWH38 3DA Kimley-Horn & Associates
PondPac k (10.00 .016.00) 2:03 PM 11/10/2006

Type.... Master Network Summary Page 1.03
Name.... Watershed
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\PREDEVELOPMENT060309BTB.ppw
•
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol
Node ID Type Event cu.ft Trun
---------- --
-----
*POA --------
D ---- ----
JCT ------
2 1134520
*POA D JCT 10 2421732
*POA D JCT 25 2970493
*POA D JCT 50 3619518
*POA D JCT 100 4286777
Max
Qpeak Qpeak Max WSEL Pond Storage
min cfs ft cu.ft
-
---------
---------
766.22 --------
122.92 -------- -
-
766.22 278.89 P~14C. ~Itt,Hh?~liE
766.22 344.76
766.22 422.12
766.22 501.09
•
•
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 2:03 PM 11/10/2006

Type.... Tc Calcs
Name.... DRAINAGE AREA A
...
Page 2.01
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\PREDEVELOPMENT060309BTB.p w
TIME OF CONCENTRATION CALCULATOR
Segment #1: Tc: TR-55 Sheet
Mannings n
Hydraulic Length
2yr, 24hr P
Slope
Avg.Velocity
08 ft/sec
Segment #1 Time: 59.92 min
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Shallow
Hydraulic Length 80.00 ft
Slope .025000 ft/ft
Unpaved
• Avg.Velocity 2.55 ft/sec
Segment #2 Time: .52 min
------------------------------------------------------------------------
Segment #3: Tc: TR-55 Channel
Flow Area
Wetted Perimeter
Hydraulic Radius
Slope
Mannings n
Hydraulic Length
Avg.Velocity
.4100
300.00 ft
3.5000 in
.013000 ft/ft
33.2500 sq.ft
18.15 ft
1.83 ft
.013000 ft/ft
.0250
920.00 ft
10.17 ft/sec
Segment #3 Time: 1.51 min
------------------------------------------------------------------------
•
S/N: FFYXYWH383DA
PondPack (10.00.016.00)
2:03 PM
Kimley-Horn & Associates
11/10/2006

Type.... Tc Calcs
~----~--
Name.... DRAINAGE AREA A
Page 2.02
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\PREDEVELOPMENT060309BTB.ppw
Segment #4: Tc: TR-55 Channel
Flow Area
Wetted Perimeter
Hydraulic Radius
Slope
Mannings n
Hydraulic Length
Avg.Velocity
9.6200 sq.ft
10.99 ft
.88 ft
020000 ft/ft
.0130
50.00 ft
14.83 ft/sec
Segment #4 Time: .06 min
------------------------------------------------------------------------
Segment #5: Tc: TR-55 Channel
Flow Area
Wetted Perimeter
Hydraulic Radius
Slope
Mannings n
Hydraulic Length
•

5.0000 sq.ft
8.32 ft
.60 ft
.016000 ft/ft
.0240
1700.00 ft
Avg.Velocity 5.59 ft/sec
Segment #5 Time: 5.07 min
------------------------------------------------------------------------
S/N: FFYXYWH383DA
PondPack (10.00.016.00)
Total Tc: 67.07 min ~-
2:03 PM
Kimley-Horn & Associates
11/10/2006

Type.... _Tc Calcs Page 2.03
Name.... DRAINAGE AREA B
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\PREDEVELOPMENT060309BTB.ppw
TIME OF CONCENTRATION CALCULATOR
Segment #1: Tc: TR-55 Sheet
Mannings n .4100
Hydraulic Length 300.00 ft
2yr, 24hr P 3.5000 in
Slope .003000 ft/ft
Avg.Velocity .05 ft/sec
Segment #1 Time: 107.72 min
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Shallow
Hydraulic Length 150.00 ft
Slope .060000 ft/ft

•
Unpaved
Avg.Velocity 3.95 ft/sec
Segment #2 Time: .63 min
------------------------------------------------------------------------
Segment #3: Tc: TR-55 Channel
Flow Area 4.5000 sq.ft
Wetted Perimeter 7.82 ft
Hydraulic Radius .58 ft
Slope .052000 ft/ft
Mannings n .1000
Hydraulic Length 655.00 ft
Avg.Velocity 2.35 ft/sec
Segment #3 Time: 4.64 min
------------------------------------------------------------------------
S/N: FFYXYWH383DA
PondPack (10.00.016.00)
Total Tc: 113.00 min '~-
2:03 PM
Kimley-Horn & Associates
11/10/2006

Type.... Tc Calcs Page 2.04
•_---
Name.... DRAINAGE AREA C
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\PREDEVELOPMENT060309BTB.ppw
TIME OF CONCENTRATION CALCULATOR
Segment #1: Tc: TR-55 Sheet
Mannings n .2400
Hydraulic Length 300.00 ft
2yr, 24hr P 3.5000 in
Slope .066700 ft/ft
Avg.Velocity .25 ft/sec
Segment #1 Time: 20.30 min
•
Segment #2: Tc: TR-55 Shallow
Hydraulic Length 540.00 ft
Slope .055600 ft/ft
Unpaved
Avg.Velocity 3.80 ft/sec
Segment #2 Time: 2.37 min
-----------------------------------------------------------------------
Segment #3: Tc: TR-55 Channel
Flow Area 2.0000
Wetted Perimeter 4.00
Hydraulic Radius .50
Slope .022000
Mannings n .1100
Hydraulic Length 1350.00
sq.ft
ft
ft
ft/ft
ft
Avg.Velocity 1.27 ft/sec
Segment #3 Time: 17.78 min
------------------------------------------------------------------------
Total Tc: 40.44 min C'-'-
•
S/N: FFYXYWH383DA
PondPack (10.00.016.00)
2:03 PM
Kimley-Horn & Associates
11/10/2006

Type.... Tc Calcs Page 2.05
Name.... DRAINAGE AREA D
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\PREDEVELOPMENT060309BTB.ppw
........................................................................
........................................................................
TIME OF CONCENTRATION CALCULATOR
........................................................................
........................................................................
Segment #1: Tc: TR-55 Sheet
Mannings n .8000
Hydraulic Length 300.00 ft
2yr, 24hr P 3.5000 in
Slope .033300 ft/ft
Avg.Velocity .07 ft/sec
Segment #1 Time: 70.21 min
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Shallow
Hydraulic Length 1440.00 ft
Slope .041700 ft/ft
Unpaved
• Avg.Velocity 3.29 ft/sec
Segment #2 Time: 7.28 min
------------------------------------------------------------------------
Segment #3: Tc:
Flow Area
Wetted Perimeter
Hydraulic Radius
Slope
Mannings n
Hydraulic Length
TR-55 Channel
2.5000 sq.ft
4.50 ft
.56 ft
.026100 ft/ft
.0110
3060.00 ft
Avg.Velocity 14.79 ft/sec
Segment #3 Time: 3.45 min
------------------------------------------------------------------------
-------------------------
-------------------------
Total Tc: 80.94 min ~~
-------------------------
-------------------------
S/N: FFYXYWH383DA
PondPack (10.00.016.00)
2:03 PM
Kimley-Horn & Associates
11/10/2006

Type.... Runoff CN-Area
Name.... DRAINAGE AREA A
Page 3.01
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\PREDEVELOPMENT060309BTB.ppw
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres $C oUC CN
-
--
-------------------------------- -
Open space (Lawns parks etc.) - Goo ---
74 ---------
43.350 ----- ----- -
--
74.00
Impervious Areas - Paved parking lO 98 2.860 98.00
Woods - good 70 16.750 70.00
COMPOSITE AREA & WEIGHTED CN --->
....................................
....................................
....
.... 62.960
..........
..........
............
............ 74.03 (74) ~-
.............
.............

•
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 2:03 PM 11/10/2006

Type.... Runoff CN-Area
Name.... DRAINAGE AREA B
Page 3.02
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\PREDEVELOPMENT060309BTB.ppw
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres $C RUC CN
-------------------------------- ---- --------- ----- ----- ------
Woods - good 70 13.100 70.00
Open space (Lawns,parks etc.) - Goo 74 1.300 74.00
COMPOSITE AREA & WEIGHTED CN ---> 14.900 70.36 (70) ~'--
. ..........................................................................
...........................................................................
•
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 2:03 PM 11/10/2006

Type.... Runoff CN-Area
Name.... DRAINAGE AREA C
Page 3.03
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\PREDEVELOPMENT060309BTB.ppw
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description
------------------------------ CN acres gC $UC CN
-- -
Open space (Lawns parks etc.) - Goo ---
74 ---------
23.000 ----- ----- ------
74.00
Impervious Areas - Paved parking lO 98 6.000 98.00
Woods - good 70 87.000 70.00
COMPOSITE AREA & WEIGHTED CN --->
....................................
....................................
....
.... 116.000
..........
.......... 72.24 (72) ~-
.........................
.........................

S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 2:03 PM 11/10/2006

Type.... Runoff CN-Area
Name.... DRAINAGE AREA D
Page 3.04
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres ~C $UC CN
-----
-------------------------------- -
Impervious Areas - Paved parking l0 ---
98 ---------
13.000 ----- ----- -
98.00
Open space (Lawns parks etc.) - Goo 74 94.000 74.00
Woods - good 70 158.000 70.00
COMPOSITE AREA & WEIGHTED CN ---> 265.000 72.79 (73) ~-
•
•
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 2:03 PM 11/10/2006

•
POST-DEVELOPMENT
STORMWATER
CALCULATIONS

20050 sss
v~

'Q• sr - Dto,J E ~oPnl Fitz'
M°9EL ,ApP/loacw
~~
~ J

Drainage Area A
•
Addlink
STEP POOL
Step Pool
Junc 10
Ex. Farm Pond
-o
o~
o-
O
G~
cow
POA A
STEP POOL SY S.
DRY PON[
m
v
a
OI
"~~:~~' Addlink 20
Drainage Area B
~'•~~:~~'~ Addlink 40
Drainage Area C POA C
~"~~i'~'~ Addlink 50
..~~
Drainage Area D POA D
POA B
•

Type.... Master Network Summary Page 2.01
Name.... Watershed
File.... T:\pn\011185028 MMM EAlamance\Stormwater Analysis\POSTDEVELOPMENT rev. 01-18-07.p
MASTER DESIGN STORM SUMMARY
Network Storm Collection: East Alamance Qu
Total
Depth Rainfall
Return Event in Type RNF ID
------------
Dev 2 ------
3.5000 ----------------
Synthetic Curve ----------------
TypeII 24hr
Dev 10 5.3000 Synthetic Curve TypeII 24hr
Dev100 7.6000 Synthetic Curve TypeII 24hr
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol Qpeak
Node ID Type Event cu.ft Trun min
-----
DRAINAGE -----
AREA --
-
A ----
AREA ------
2 ---------- --
283377 ---------
760.00
DRAINAGE AREA A AREA 10 595544 751.50
DRAINAGE AREA A AREA 100 1044352 751.50
DRAINAGE AREA B AREA 2 18662 745.00
DRAINAGE AREA B AREA 10 91865 744.50
DRAINAGE AREA B AREA 100 76322 744.50
DRAINAGE AREA C AREA 2 650303 715.50
DRAINAGE AREA C AREA 10 1120020 715.00
DRAINAGE AREA C AREA 100 1736604 715.00
DRAINAGE AREA D AREA 2 1087.654 766.50
DRAINAGE AREA D AREA 10 2321693 766.00
DRAINAGE AREA D AREA 100 4109689 766.00
DRY POND IN POND 2 187481 859.00
DRY POND IN POND 10 465821 833.00
DRY POND IN POND 100 576887 785.50

Max
Qpeak Max WSEL Pond Storage
--cfs--- ---ft--- ---cu~ft
35.54
78.59
140.34
2.85
6.93
12.91
277.44
466.08
705.01
117.74
267.09
480.04
7.70
13.23
13.47
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 2:26 PM 1/18/2007

Type.... Master Network Summary Page 2.02
Name.... Watershed
File.... T:\pn\011185028 MMM EAlamance\Stormwater Analysis\POSTDEVELOPMENT rev. O1-18-07.p
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol
Node ID Type Event cu.ft Trun
-----
DRY -----
POND -------
OUT ----
POND ------
2 ---------- --
164332
DRY POND OUT POND 10 435736
DRY POND OUT POND 100 540278
EX. FARM PONDIN POND 2 283377
EX. FARM PONDIN POND 10 595544
EX. FARM PONDIN POND 100 1044352
+EX. FARM PONDOUT POND
+EX. FARM PONDOUT POND
+EX. FARM PONDOUT POND
HEADWALL
HEADWALL
HEADWALL
• *POA A
*POA A
*POA A
JCT
JCT
JCT
JCT
JCT
JCT
*POA B
*POA B
*POA B
*POA C
*POA C
*POA C
*POA D
*POA D
* POA D
STEP POOLS
STEP POOLS
STEP POOLS
•
JCT
JCT
JCT
JCT
JCT
JCT
JCT
JCT
JCT
IN POND
IN POND
IN POND
2 194601
10 500873
100 943928
2 190208
10 468598
100 579613
2
10
100
4393
32324
364314
2
10
100
2
10
100
2
10
100
2
10
100
182984
477603
616598
650303
1120020
1736604
1087654
2321693
4109689
190206
468546
579611
Max
Qpeak Qpeak Max WSEL Pond Storage
min cfs ft cu.ft
---------
1042.50 --------
4.61 -------- ------------
587.48
55912
1034.50 13.10 ~
589.08 88504
1008.50 13.19 589.08 88581
760.00 35.54 v~-sE~L S~RFACr
751.50 78.59 EL~pT.~
751.50 140.34
856.50 7.79 615.8
143123
840.00 18.85 1
616.65 296515
788.00 81.78 617.24 406075
858.00 7.70
829.00 13.23
788.00 13.47
823.00 .09
839.50 5.62
768.00 68.31
1043.50 9.83
1029.50 13.53
990.00 13.93
715.5 0 2 7 7. 4 4 ~o ST 'DLJE~aP~E~T
715.00 466.08 QEAk 'D1SCp.MCtrE
715.00 705.01 AT ~E,SQEG'C\Vl`
~(SlS (~D1a~S
A.JAI
766.50 117.74 .
766.00 267.09
766.00 480.04
857.00 7.69
832.00 13.23
787.50 13.47
S/N: FFYXYWH383DA
PondPack (10.00.016.00)
2:26 PM
Kimley-Horn & Associates
1/18/2007

Type.... Master Network Summary Page 2.03
Name.... Watershed
File.... T:\pn\011185028 MMM EAlamance\Stormwater Analysis\POSTDEVELOPMENT rev. 01-18-07.p
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Max
Return HYG Vol Qpeak Qpeak Max WSEL Pond Storage
Node ID Type Event cu.ft Trun min cfs ft
-- cu.ft
-----------
------
STEP -------
POOLS ---- ----
OUT POND ------
2 ---------- --
187481 ---------
859.00 --------
7.70 ------
592.31 -
3327
STEP POOLS OUT POND 10 465821 833.00 13.23 592.44 3588
STEP POOLS OUT POND 100 576887 785.50 13.47 592.45 3599
•
•
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 2:26 PM 1/18/2007

Type.... Tc Calcs Page 1.01
Name.... DRAINAGE AREA A
• File.... T:\pn\011185029 E. Alamance\Stormwater Analysis\POSTDEVELOPMENT_RTL_ICPR.ppw
•
•
TIME OF CONCENTRATION CALCULATOR
Segment #1: Tc: TR-55 Sheet
Mannings n .4100
Hydraulic Length 300.00 ft
2yr, 24hr P 3.5000 in
Slope .013000 ft/ft
Avg.Velocity .08 ft/sec
Segment #2: Tc: TR-55 Shallow
Hydraulic Length 80.00 ft
Slope .025000 ft/ft
Unpaved
Avg.Velocity 2.55 ft/sec
Segment #2 Time: .52 min
------------------------------------------------------------------------
Segment #3: Tc: TR-55 Channel
Flow Area 33.2500 sq.ft
Wetted Perimeter 18.15 ft
Hydraulic Radius 1.83 ft
Slope .013000 ft/ft
Mannings n .0250
Hydraulic Length 920.00 ft
Avg.Velocity 10.17 ft/sec
Segment #3 Time: 1.51 min
------------------------------------------------------------------------
Segment #1 Time: 59.92 min
S/N: FFYXYWH383DA
PondPack (10.00.016.00)
1:56 PM
Kimley-Horn & Associates
11/10/2006

Type.... Tc Calcs
Name.... DRAINAGE AREA A
Page 1.02
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\POSTDEVELOPMENT_RTL_ICPR.ppw
Segment #4: Tc: TR-55 Channel
•
r~
-------------------------
Total Tc: 67.07 min ~-
S/N: FFYXYWH383DA
PondPack (10.00.016.00)
Flow Area
Wetted Perimeter
Hydraulic Radius
Slope
Mannings n
Hydraulic Length
Avg.Velocity
9.6200 sq.ft
10.99 ft
.88 ft
020000 ft/ft
.0130
50.00 ft
19.83 ft/sec
Segment #4 Time: .06 min
------------------------------------------------------------------------
Segment #5: Tc: TR-55 Channel
Flow Area 5.0000 sq.ft
Wetted Perimeter 8.32 ft
Hydraulic Radius .60 ft
Slope .016000 ft/ft
Mannings n .0240
Hydraulic Length 1700.00 ft
Avg.Velocity 5.59 ft/sec
Segment #5 Time: 5.07 min
1:56 PM
Kimley-Horn & Associates
11/10/2006

Type.... Tc Calcs
Name.... DRA AREA B
Segment #1: Tc: TR-55 Sheet
Mannings n .4100
Hydraulic Length 300.00 ft
2yr, 24hr P 3.5000 in
Slope .030000 ft/ft
• File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\POSTDEVELOPMENT_RTL_ICPR.ppw
TIME OF CONCENTRATION CALCULATOR
Avg.Velocity .12 ft/sec
Segment #1 Time: 42.88 min
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Shallow
•
[7
Hydraulic Length 150.00 ft
Slope .060000 ft/ft
Unpaved
Avg.Velocity 3.95 ft/sec
Segment #2 Time: .63 min
------------------------------------------------------------------------
Segment #3: Tc: TR-55 Channel
Flow Area 4.5000 sq.ft
Wetted Perimeter 7.82 ft
Hydraulic Radius .58 ft
Slope .052000 ft/ft
Mannings n .1000
Hydraulic Length 655.00 ft
Avg.Velocity 2.35 ft/sec
Page 1.05
Segment #3 Time: 4.64 min
------------------------------------------------------------------------
S/N:. FFYXYWH383DA
PondPack (10.00.016.00)
Total Tc: 48.16 min F---
1:56 PM
Kimley-Horn & Associates
11/10/2006

Type.... Tc Calcs
Name.... DRAINAGE AREA C
Page 1.07
• File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\POSTDEVELOPMENT_RTL_ICPR.ppw
........................................................................
........................................................................
TIME OF CONCENTRATION CALCULATOR
........................................................................
........................................................................
Segment #1: Tc: User Defined
Segment #1 Time: 5.00 min
------------------------------------------------------------------------
•

-------------------------
-------------------------
Tota.l Tc: 5.00 min ~-
-------------------------
-------------------------
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 1:56 PM 11/10/2006

Type.... Tc Calcs
Name.... DRAI REA D
Page 1.10
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\POSTDEVELOPMENT RTL ICPR.ppw
........................................................................
........................................................................
TIME OF CONCENTRATION CALCULATOR
........................................................................
........................................................................
Segment #1: Tc: TR-55 Sheet
Mannings n .8000
Hydraulic Length 300.00 ft
2yr, 24hr P 3.5000 in
Slope .033300 ft/ft
Avg.Velocity .07 ft/sec
Segment #1 Time: 70.21 min
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Shallow
Hydraulic Length 1440.00 ft
Slope .041700 ft/ft
Unpaved
• Avg.Velocity 3.29 ft/sec
Segment #2 Time: 7.28 min
------------------------------------------------------------------------
Segment #3: Tc: TR-55 Channel
Flow Area 2.5000 sq.ft
Wetted Perimeter 4.50 ft
Hydraulic Radius .56 ft
Slope .026100 ft/ft
Mannings n .0110
Hydraulic Length 3060.00 ft
Avg.Velocity 14.79 ft/sec
Segment #3 Time: 3.45 min
------------------------------------------------------------------------
------------------------
------------------------
Total Tc: 80.94 min E'-
------------------------
------------------------
•
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 1:56 PM 11/10/2006

Type.... Runoff CN-Area
Name.... DRAINAGE AREA A
Page 2.01
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\POSTDEVELOPMENT RTL ICPR.ppw
• - -
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description
-------------------------------- - CN
--- acres
-
- gC RUC CN

Open space (Lawns,parks etc.) - Goo
74 -
------
43.350 ----- ----- ------
74.00
Impervious Areas - Paved parking lO 98 2.860 98.00
Woods - good 70 16.750 70.00
COMPOSITE AREA & WEIGHTED CN --->
....................................
....................................
....
.... 62.960
..........
..........
............
............ 74.03 (74) E---
.............
.............

•
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 1:56 PM 11/10/2006

Type.... Runoff CN-Area
Name.... DRAINAGE AREA B
..~_
Page 2.03
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\POSTDEVELOPMENT RTL ICPR.ppw
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres $C $UC CN
-------------------------------- ---- --------- ----- ----- ------
Woods - good 70 4.500 70.00
Open space (Lawns,parks etc.) - Goo 74 .600 74.00
COMPOSITE AREA & WEIGHTED CN ---> 5.100 70.47 (70)
...........................................................................
...........................................................................
•
•
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 1:56 PM 11/10/2006

Type.... Runoff CN-Area
Name.... DRAINAGE AREA C
c_ -
Page 2.06
. File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\POSTDEVELOPMENT_RTL_ICPR.ppw
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description
-------------------------
- CN acres $C RUC CN
--
---- -
Open space (Lawns parks etc.) - Goo ---
74 ---------
15.000 ----- ----- ------
74.00
Impervious Areas - Paved parking lO 98 50.000 98.00
Woods - good 70 11.000 70.00
COMPOSITE AREA & WEIGHTED CN --->
....................................
....................................
....
.... 76.000
..........
..........
............
............ 89.21 (89) ~~
.............
.............
•
•
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 1:56 PM 11/10/2006

Type.... Runoff CN-Area
Name.... DRAINAGE AREA D
Page 2.07
File.... T:\pn\011185024 E. Alamance\Stormwater Analysis\POSTDEVELOPMENT RTL ICPR.ppw
- -
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres $C RUC CN
-------------------------------- -
Impervious Areas - Paved parking lO ---
98 ---------
13.000 ----- ----- ------
98.00
Open space (Lawns parks etc.) - Goo 74 94.000 74.00
Woods - good 70 197.000 70.00
COMPOSITE AREA & WEIGHTED CN --->
....................................
....................................
....
.... 259.000
..........
.......... 72.91 (73) ~~
.........................
.........................
•
S/N: FFYXYWH383DA Kimley-Horn & Associates
PondPack (10.00.016.00) 1:56 PM 11/10/2006

C7
APPENDICES
•
20450 ~~~
YZ

D
C
Table 8.03b
Runoff Curve Numbers (CN)
Hydrologic Soil Group ,
p B C D_
Land Use/Cover
Cultivated land
without conservation -
72
81
88
91
with conservation 62 71 78 81
Pasture land
poor condition
68
79
86
89
fair condition
~ ~ 49
39 69
61 79
74 84
80
good condition
Meadow '
good"condition
30
58
71
78
Wood orforest land
Thin stand -poor cover, no mulch
45
66
83
Good stand..- good cover 25 55 70 77
Open spaces; lawns, parks, golf courses, cemeteries, etc.
good condition:
grass cover on 75%
-
or more of the area 39 61 74 80
- fair condition:
grass cover on 50 .
to 75% of the area
49
69 -
79
84
Commercial and business
areas (85% impervious)
89
92
94
95
Industrial districts
(72% impervious)
81
88
91
93
ResidentiaL~ Development completed and vegetation established
Average lot size Average % Impervious' .
77
85
90
92
1/8 acre or less 65
1 /4 acre 38 6 t 75 83 87
1/3 acre 30 -"
1/2 acre- 25 57
54 72
70 81
80 .86
85
1 acre 20
' 2 acre 15 51
47 68
66 79
77 84
81
Paved parking lots, roofs,
98
98
driveways, etc. 98 98 .
Streets and roads
paved with curbs and _
~
98
98 ~
98
98
storm sewers
gravel ~
76
85
89 .
91
.dirt. 72 82 87 89
Newly graded area- 81 89 93 95
Residential: Development underway and no,vegetation
Lot sizes of 1!4 acre 88
85 93
91 95
94 97
96
Lot sizes of 1/2 acre
Lot sizes of 1 acre 82 90 93 95
Lot sizes of 2 acres 81 89 92- 94
~Curoe numbers are computed assuming the runoff from the house and driveway is directed toward the street.
source: USDA-SCS
•

5.0.10

Rev u193 .

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8.03.11

Appendices

Exhibit 3
•
rational runoff coefi:icients
- C C
Description of surface ASCE, 1975 Malcom
Viessman, et al, 1996
•
•
Business:
Downtown areas 0.70-0.95 0.85
Neighborhood areas 0:50-0.70
Residential: •
Single-family areas 0.30-0.50
6 dwellings/ac 0.55
4 dwellings/ac 0.50
2 dwellings/ac 0.40 -
Multiunits, detached 0.40-0.60
10 dwellings/ac 0.60 •
Multiunits, attached 0.60-0.75
Residential (suburban) 0.25-0.40
Apartment dwelling areas 0.50-0.70 0.60 -
Schools, churches 0.60
Industrial -
Light areas - 0.50-0.80
Heavy arias 0.60-0.90
Parks, cemeteries. 0.10-0.25 0.25
Playgrounds 0.20-0.35 0.35 •
Railroad yard areas. 0.20-0.40
Unimproved areas 0.10-0.30 - 0.35
Streets:
Asphaltic ~ 0.70-0.95 0.95 ~--
Concrete 0.80-0.95 0.95
Brick 0.7o-o.ss o.8s
Drives and walks 0.75-0.85 0.95- E--
Roofs ~ 0.75-0.95 '
Inclined 1.00
Flat 0.90
Lawns; sandy soil: .. '
Flat, 2% 0.05-0.10 0.10
Average, 2-7% 0.10-0.15 -,0.15
Steep, 7% . 0.15-0.20
Lawns; heavy soil:
Flat, 2°~ 0.13-0.17
Average, 2-7% 0.18-0.22 ~ 0.15
Steep, 7% 0.25-0.35 0.35 Q--
Wooded areas:
Sparse ground litter 0.20 ~
Deep ground litter 0.10
ASCE and Viessman suggest the above values for return periods of 2-10 years.
For more severe storms, the following multipliers are suggested for C:
Return aeriod furl Multiplier
- 25 1.1
50 1.2
100 1.25
CopyrightH.R Malcom, 2003
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MORPHOLOGICAL DATA
Martin Marietta Materials -East Atamance Quarry
•
•
•
Boyd's Creek
VARIABLES Existing Reach
1. Stream T e
Ros en E3/4
2. Draina a Area
s .mile 3.2
~
~~e ~-•
~~ _,~ _ ..,~.
4. Bankfull Mean Mean: 2.1
depth (db~) Range: 2.0 2.4
4"` yyldtfalt-e~ ado ~ N!
~7x e . . ~b~b..~ ^
6. Bankfull cross-sectional Mean: 53.9
Area (Aekr) Range: 45.6 59.5
~~:
._ ~ "_ L~Aeact ~ ei_..u. ea ; s

...g~ . ;
~

, R
8. Bankfull Discharge , cfs Mean: 308.0
(Q~„) Range: 248.6 32? 7
~,a5 Bankfiillt~tazimuni De thr~sn w~r'sn~' ` Meat1 ~` `'
.f .:'?-' /
ldmei) "~i~..yr.. ~Lv~~f,~l"~ r q ~. ~ yea ~. 9 ~~,
to Max d~,,,idG„ Mean: 1.5
ratio Range: 1.1 1.9
.i w~`~s~~. t':ow_Bank ei ht.:to t~a~x:~~~n'. M aii 's~k~.?
_
,

~)` del .~,.
.,
drk~F~atio" ,,,fi~:
~ ~. ,
.~~:._~
12. Width of Flood Prone Mean: 91 .8
Area (Wr„) Range: 73.1 147.1
~.
EntrepcFimenf :a~i ` ."
M n..
,

14. Meander Len th Mean: 55.3
(Lm) Range: 36.0 65.0
~ ~ati0~o~37v1 rid'ei~~n tt~~to, Me" n
., .
16. Radius of Gwvature Mean: 36.3
(R~) Range: 20.8 71.6
~=~'_~ at)o°pof?R~a~4us'I'of:~ur;7aturs. •. _ M ~:`
>;`;;a`~~ ~QBar,~"kfu111N,~dttj'~R~vVEki)_
18. Belt Width Mean: 23.6
(Wyk Range: 16.6 35.2
:~xa,19: t~t~aradeT~141adtfi'at~o ~~~';a `.':.. ea

20. Sinuosi k Mean: 1.01
Stream Len th /Valley den th Ran e: -- -

~ lilft s?•~' fly bt~DO~ ~~~
22 Avera e Stream Slo .e Mean: 0.0056
(Say) _ (S~e„Q,Jk) Range: 0.0050 0.0061
_ x'.23': Ritf1~~,SIC! r ~r t" ,ro r;', Mean_,
1 ~ ~'~~'~ ~~.. .., r . '~,: ~ p
~a, .. ~ v ~ 0 ~r
24. Ratio of Riffle Slo a to Av . Mean: 4.5
Slope (S,;~~/S„~) Range: 0.6 9.4
ti%T~r,<25. Rool;Slo ~.~,= ~=~r"'~~': w .ate ~ " a(1. -
~ ~'
26. Ratio of Pool Slo a to Av . Mean: 0.2
Slope (Sp„~lS,~) Range: 0.1 0.3
,~ ~:.~~275 ~flaXt"
X-~
. ;:
28. Ratio of Pool De th to Av Mean: 0.6
Depth (d,oo,/da„9) Range: 0.3 0.8
,c'3 ~ . ~.©A s~
~
,.;_
,, ~
~ ~, 9f
32. Ratio of Pool to Pool S acin Mean: 5
to Bankfull Width (p-p/Wbkr) Range: 1 18
'Based on The Reference Reach Field Book, Rosgen Stream type and Associated Manning's "n" Coefficient
C:1Documenls and Settingsyason.diaz\Desktop\EAlamance Morph.xls
8!1/2006

• • •
Boyd's Creek Profile
560.0
559.5
559.0
558.5
558.0
557.5
557.0
556.5
.-.
~ 556.0
C
~ 555.5
:~
(6
~ 555.0
W
554.5
554.0
553.5
553.0
552.5
552.0
551.5
551.0
550.5
550 0
~ CH
O WS
• BKF
• P1
O P2
+ P3
X P4
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400
Distance along stream (ft)

• •
Boyd's Creek Cross Section 1
O Ground Points • Bankfull Indicators • Water Surface Points
Wbkf = 22.2 Dbkf = 2.1 Abkf = 45.6
580
579
578
577
576
575
574
573
572
571
570
569
~-.
~ 568.
p 567
~ 566
~ 565
LLJ 564
563
562
561
560
559
558
557
556
555
554
553
552
551
550
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250
•
Horizontal Distance (ft)

• •
Boyd's Creek Cross Section 2
O Ground Points • Bankfull Indicators • Water Surface Points
Wbkf = 22.9 Dbkf = 2.9
4=
C
O
t6
N
W
/ Overlay
Abkf = 53.9
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250
580
579
578
577
576
575
574
573
572
571
570
569
568
567
566
565
564
563
562
561
560
559
558
557
556
555
554
553
552
551
550
~"
Horizontal Distance (ft)

• •
Boyd's Creek Cross Section 3
O Ground Points • Bankfull Indicators • Water Surface Points
Wbkf = 29.4 Dbkf = 2 Abkf = 59.4
580
579
578
577
576
575
574
573
572
571
570
569
...
~ 568
CO 567
~ 566
N 565
W 564
563
562
561
560
559
558
557
556
555
554
553
552
551
550
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250
•
Horizontal Distance (ft)