20190998 Ver 1_SIA_2019-06-20_20190724

STORMWATER IMPACT ANALYSIS
PARK APARTMENTS / WDF-17000 / JUNE 2019
PARK APARTMENTS
CHAPEL HILL, NC
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NARRATIVE > WDF-17000
2905 Meridian Parkway, Durham, NC 27713 / 919. 361. 5000creatingexperiences through experience
PARK APARTMENTS
Stormwater Impact Analysis
GENERAL DESCRIPTION
Park Apartments is an approximately 13.66-acre proposed multi-family development off Ephesus Church Road in Chapel
Hill, North Carolina. The proposed project is an existing site to be redeveloped, The Park at Chapel Hill Apartments.
Existing buildings, parking lots, utilities, and other supporting infrastructure will be removed and replaced with new
buildings, parking, and associated utilities and infrastructure.
The proposed development is located within the Cape Fear River basin, with stormwater runoff from the proposed
development draining to Brooker Creek. According to the N.C. Division of Water Resources’ NC Surface Water
Classifications Map, Brooker Creek (Stream Index #16-41-1-15-2-(5)) is classified as WS-IV;NSW at this location.
Per City of Chapel Hill regulations, stormwater management on this site shall meet the stormwater management
performance standards for development set forth in Chapel Hill “Land Use Management Ordinance (LUMO) Sec. 3.11
Ephesus/Fordham Form District – Version March 6, 2017”.
The regulations are as follows:
Applicability (Chapel Hill Land Use Management Ordinance (LUMO) Sec. 3.11.4.3.C Ephesus/Fordham Form District).
1.This section applies to all new development and redevelopment projects for which a form district permit is required.
No development or redevelopments for which a form district permit is required pursuant to this section shall occur
except in compliance with the provisions, conditions, and limitations of the permit.
Design and Performance Standards (Chapel Hill Land Use Management Ordinance (LUMO) Sec. 3.11.4.3.F Ephesus/Fordham
Form District).
1.Stormwater treatment shall be designed to achieve average annual 85% total suspended solids (TSS) removal and must
apply to the volume of post-development runoff resulting from the one-inch of precipitation. Alternative treatment
methods to achieve 85% annual TSS removal may be acceptable. The 85% requirement applies to 85% of the additional;
suspended solids that are the result of the new development.
2.The stormwater runoff volume leaving the site post-development shall not exceed the stormwater runoff volume
leaving the site pre-development (existing conditions) for the local 2-year frequency, 24-hour duration storm event for
all development. This may be achieved by hydrologic abstraction, recycling and/or reuse, or any other accepted
scientific method.
3.The stormwater runoff rate leaving the site post-development shall not exceed the stormwater runoff rate leaving the
site pre-development (existing conditions) for the local 1-year, 2-year, and 25-year 24-hours storm events.
4.Notwithstanding subsection 3.11.4.3.F.1, the minimum impervious area treated for eighty-five (85) percent average
annual TSS removal shall be fifty (50) percent of the post-construction total impervious area.
To meet the above Town of Chapel Hill standards, one dry detention pond and a StormFilter system are proposed.
This report contains the calculations detailing the expected stormwater impacts as a result of the proposed
NARRATIVE > WDF-17000
creating experiences through experience 2 of 3
development, along with the final design of the dry detention pond and StormFilter system that will be used to
mitigate impacts. Please refer to the appropriate section of this report for additional information.
CALCULATION METHODOLOGY
§Rainfall data for this area in the Chapel Hill, NC, region is from NOAA Atlas 14. This data contains a depth-
duration-frequency (DDF) table describing rainfall depth versus time for varying return periods in the area.
These rainfall depths are input into the meteorological model within PondPack for peak flow rate calculations.
Please reference the precipitation information section within this report for additional information.
§A composite SCS Curve Number was calculated for the post-development condition for each subbasin using
SCS curve numbers and land cover conditions. Land cover conditions for the pre-development condition were
taken from a combination of field survey information and aerial imagery. Land cover conditions for the post-
development condition were taken from the proposed development plan.
§Using WebSoil Survey, the on-site soils were determined to be hydrologic soil group (HSG) ‘D’ soils. Since the
method chosen to compute pre- and post-development peak flow rates and runoff volumes is dependent upon
the soil type, care was taken when selecting the appropriate Soil Conservation Service Curve Number (SCS CN).
-Within each sub-basin, an approximate proportion of each soil group was determined using Web Soil Survey
Maps. Once an approximate proportion was determined, a composite SCS CN was computed for each cover
condition.
§The time of concentration was calculated using SCS TR-55 (Segmental Approach, 1986). The Tc flow path can
be divided into three segments: overland flow, concentrated flow, and channel flow. The travel time was then
computed for each segment, from which the overall time of concentration was determined by taking the sum
of each segmental time.
§Existing topographic information used in this analysis is from an onsite survey conducted by McAdams Company
and Orange County GIS for offsite drainage areas.
§The lot west of Street ‘A’ and north of Elliot Road will not be built-out in the current phase of the project, as
such it is modeled as open space in post-development hydrologic condition (referred to as ‘Subbasin 1B-
Bypass’ in this report).
§PondPack Version V8i was used in determining the post-development peak flow rates for the 1-year, 2-year,
25-year, and 100-year storm event, as well as routing calculations for the proposed stormwater control
measure.
§A dry pond is proposed on this site to manage peak flows from stormwater runoff from the proposed
development in Subbasins 1-to SCMA and 1-SCM B. Contech StormFilter is proposed to meet water quality
requirements.
NARRATIVE > WDF-17000
creating experiences through experience 3 of 3
§The runoff volume difference Pre- to Post-development in the 2-year 24-hour storm event is greater than the
volume from the Water Quality event captured in the Stormfilter system. This volume difference will be
captured and treated within the proposed dry detention pond. To ensure adequate treatment within the dry
detention pond, the 2-year Volume Storage will be detained by a 4.0” orifice on the outlet riser structure that
will slowly release the 2-year Volume Storage.
§The Ephesus/Fordham District requires that a minimum of 50% of proposed development must be treated for
TSS removal. All impervious allocated on the proposed future phase lot must be treated for TSS removal.
§TN-Export and TP-Export calculations were computed using the Stormwater Nitrogen and Phosphorous Tool
v4.0.
DISCUSSION OF RESULTS
PEAK RUNOFF CONTROL REQUIREMENTS
The peak flow for the 1-yr, 2-yr, and 25-yr storm meets peak flow requirements at POA#1. Please refer to the Summary
of Results for the reduction in flows from the pre- to post-development condition.
POLLUTANT AND NUTRIENT CONTROL REQUIREMENTS
The site meets the 10 lbs/ac/yr maximum nitrogen loading rate using the proposed on-site StormFilter system.
Additionally, 85% TSS removal requirements are met by the StormFilter system. Water quality calculations will need to
be amended with the future development of the remaining lot.
CONCLUSION
If the development on this tract is built as proposed within this report, then the requirements set forth in
Ephesus/Fordham regulations will be met without additional stormwater control measures. However, modifications to
the proposed development may require that this analysis be revised. Some modifications that would require this
analysis to be revised include:
1.The proposed site impervious surface exceeds the amount accounted for in this report.
2.The post-development watershed breaks change significantly from those used to prepare this report.
The above modifications may result in the assumptions within this report becoming invalid. The computations within
this report will need to be revisited if any of the above conditions become apparent as development of the proposed
site moves forward.
7 NUTRIENT LOADING CALCULATIONS
1 SUMMARY OF RESULTS
2 MISCELLANEOUS SITE INFORMATION
6 STORMWATER CONTROL MEASURE 'B'
CALCULATIONS
5 STORMWATER CONTROL MEASURE 'A'
CALCULATIONS
3 PRE-DEVELOPMENT HYDROLOGIC
CALCULATIONS
4 POST-DEVELOPMENT HYDROLOGIC
CALCULATIONS
PARK APARTMENTS
WDF-17000
SUMMARY OF RESULTS
PARK APARTMENTS
WDF-17000
SUMMARY OF RESULTS C. BALLARD
6/20/2019
RELEASE RATE MANAGEMENT RESULTS
Return Period Pre-Dev Post-Dev Post-Dev % Increase
without SCM with SCM
[cfs][cfs][cfs][%]
1-Year 34.20 52.39 34.03 -0.5%
2-Year 43.80 64.61 41.53 -5.2%
25-Year 72.32 98.69 70.33 -2.8%
Return Period Pre-Dev Post-Dev Post-Dev % Increase
without SCM with SCM
[cfs][cfs][cfs][%]
1-Year 0.90 0.00 0.00 -100%
2-Year 1.16 0.00 0.00 -100%
25-Year 1.91 0.00 0.00 -100%
POINT OF ANALYSIS #1
POINT OF ANALYSIS #2
PARK APARTMENTS
WDF-17000
SUMMARY OF RESULTS
Runoff Volume Management
C. BALLARD
6/20/2019
==> 2-YEAR VOLUME MANAGEMENT RESULTS
PRE-DEVELOPMENT 2YR-24HR VOLUME SUMMARY
Total On-Site Area =13.66 acres
Area Weighted On-site SCS CN =88
S =1.37
P (2-yr / 24-hour) =3.57 inches
Q* =2.33 inches
On-site Run-off Volume =2.65 acre-feet
=115,489 cf
POST-DEVELOPMENT 2YR-24HR VOLUME SUMMARY
Total On-Site Area =13.66 acres
Area Weighted On-site SCS CN =92
S =0.90
P (2-yr / 24-hour) =3.57 inches
Q* =2.68 inches
Total On-site Run-off Volume =3.05 acre-feet
=132,823 cf
PRE TO POST-DEVELOPMENT 2YR-24HR VOLUME DIFFERENCE
Pre-Post 2yr Runoff Volume Difference =17,334 cf
SUMMARY OF 2YR-24HR VOLUME CAPTURE
SCM A - Dry Pond Volume Captured =4,409 cf
SCM B - Stormfilter System Volume Captured =12,965 cf
Total Pre-Post 2yr Runoff Volume Detained =17,374 cf
PARK APARTMENTS
WDF-17000
SUMMARY OF RESULTS
SCM A - Dry Pond
C. BALLARD
6/20/2019
STORMWATER CONTROL MEASURE SUMMARY
Design Drainage Area =8.64 ac
Design Impervious Area =5.99 ac
% Impervious =69.3%
Top of Dam =262.00 ft
Bottom of Pond =256.50 ft
Orifice Diameter =4.00 in
Orifice Invert Elevation =256.50 ft
Number of Area Orifices =3
Area Orifice Dimensions =1.5' (L) x 1.0' (H)
Area Orifice Invert Elevation =257.30 ft
Riser Size =5' x 5'
Riser Crest =260.20 ft
Barrel Diameter =30 in
# of Barrels =1
Upstream Invert =256.50 ft
Downstream Invert =256.00 ft
Length =26 ft
Slope =0.0192 ft/ft
STORMWATER CONTROL MEASURE ROUTING RESULTS
Return Period Inflow Outflow Max. WSE Freeboard
[cfs][cfs][ft][ft]
1-Year 31.99 16.42 259.25 2.75
2-Year 39.40 19.64 259.74 2.26
10-Year 53.45 31.46 260.55 1.45
25-Year 59.67 38.42 260.81 1.19
100-Year 68.08 43.15 261.23 0.77
100-Year - Worst Case***68.08 43.29 261.25 0.75
*** See narrative for explanation of the modeled worst case scenario
*Dry Pond sized for both
Subbasins 1 to SCM A
and 1 to SCM B
PARK APARTMENTS
WDF-17000
ONSITE IMPERVIOUS TRACKING K.GARCIA, PE
6/19/2019
Park Apartments Impervious Treatment
Total Onsite Impervious* =474,666 sf
Required Imp Treatment* =237,333 sf 50% treatment requirment
Onsite Imp Treated =282,874 sf
Onsite Imp Treated Over Req. =45,541 sf
Onsite Elliot Rd ROW Imp = 76,940 sf
Elliot Rd ROW Treated = 39,750 sf
Elliot Rd ROW Imp Bypass =37,443 sf
Oniste Imp. Percentage Treated =59.6%
Elliot Rd Bypass Imp Percentage =7.9%
* For future lot, assumed 90% onsite impervious area and all impervious area treated
New Graph
POA 1 - Pre-Dev 1yr-24hr - Flow POA 1 - Post-Dev 1yr-24hr - FlowFlow (ft³/s)35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
Time (min)
1,440.001,296.001,152.001,008.00864.00720.00576.00432.00288.00144.000.00
New Graph
POA 1 - Pre-Dev 2 yr-24 hr - Flow POA 1 - Post-Dev 2 yr-24 hr - FlowFlow (ft³/s)45.00
40.00
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
Time (min)
1,440.001,296.001,152.001,008.00864.00720.00576.00432.00288.00144.000.00
New Graph
POA 1 - Pre-Dev 25 yr-24 hr - Flow POA 1 - Post-Dev 25 yr-24 hr - FlowFlow (ft³/s)75.00
68.75
62.50
56.25
50.00
43.75
37.50
31.25
25.00
18.75
12.50
6.25
0.00
Time (min)
1,440.001,296.001,152.001,008.00864.00720.00576.00432.00288.00144.000.00
New Graph
POA-2 - Pre-Dev 1yr-24hr - Flow POA-2 - Post-Dev 1yr-24hr - FlowFlow (ft³/s)1.00
0.88
0.75
0.63
0.50
0.38
0.25
0.13
0.00
Time (min)
1,440.001,296.001,152.001,008.00864.00720.00576.00432.00288.00144.000.00
New Graph
POA-2 - Pre-Dev 2 yr-24 hr - Flow POA-2 - Post-Dev 2 yr-24 hr - FlowFlow (ft³/s)1.25
1.13
1.00
0.88
0.75
0.63
0.50
0.38
0.25
0.13
0.00
Time (min)
1,440.001,296.001,152.001,008.00864.00720.00576.00432.00288.00144.000.00
New Graph
POA-2 - Pre-Dev 25 yr-24 hr - Flow POA-2 - Post-Dev 25 yr-24 hr - FlowFlow (ft³/s)2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0.00
Time (min)
1,440.001,296.001,152.001,008.00864.00720.00576.00432.00288.00144.000.00
PARK APARTMENTS
WDF-17000
MISCELLANEOUS SITE INFORMATION
NC Center for Geographic Information & Analysis, Esri, HERE, Garmin, ©OpenStreetMap contributors
0 500 1,000250Feet1 inch = 500 feet
¯PARK APARTMENTSSITE AERIAL MAPPROJECT #: WDF-17000
CHAPEL HILL, NORTH CAROLINA
Copyright:© 2013 National Geographic Society, i-cubed
0 2,000 4,0001,000 Feet1 inch = 2,000 feet
¯PARK APARTMENTSUSGS TOPO MAPPROJECT #: WDF-17000CHAPEL HILL, NORTH CAROLINA
Hydrologic Soil Group—Orange County, North Carolina
(PROPERTY)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/13/2018
Page 1 of 439781903978240397829039783403978390397844039784903978190397824039782903978340397839039784403978490678270678320678370678420678470678520678570678620678670678720678770
678270 678320 678370 678420 678470 678520 678570 678620 678670 678720 678770
35° 56' 4'' N 79° 1' 26'' W35° 56' 4'' N79° 1' 5'' W35° 55' 53'' N
79° 1' 26'' W35° 55' 53'' N
79° 1' 5'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 17N WGS84
0 100 200 400 600
Feet
0 35 70 140 210
Meters
Map Scale: 1:2,460 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:20,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Orange County, North Carolina
Survey Area Data: Version 18, Sep 10, 2018
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Apr 27, 2014—May
6, 2014
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Hydrologic Soil Group—Orange County, North Carolina
(PROPERTY)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/13/2018
Page 2 of 4
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
Ch Chewacla loam, 0 to 2
percent slopes,
frequently flooded
B/D 0.5 3.5%
Ur Urban land 1.3 9.3%
WtC2 White Store clay loam, 6
to 15 percent slopes,
moderately eroded
D 0.5 3.5%
WwC White Store-Urban land
complex, 2 to 8
percent slopes
D 11.4 83.7%
Totals for Area of Interest 13.7 100.0%
Hydrologic Soil Group—Orange County, North Carolina PROPERTY
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/13/2018
Page 3 of 4
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Orange County, North Carolina PROPERTY
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
11/13/2018
Page 4 of 4
NC DENR - DIVISON OF WATER RESOURCES
Name of Stream Description Class Class Date Index No.
2B .0300
. 0311 CAPE FEAR RIVER BASIN
Cedar Fork WS-V,B;NSW 08/11/09 16-41-1-15-2-3From source to Eastwood Lake,
Booker Creek
Unnamed Tributary at Wright
Mobile Homes
WS-V,B;NSW 08/11/09 16-41-1-15-2-3-1From source to Cedar Fork
Booker Creek WS-V;NSW 08/11/09 16-41-1-15-2-(4)From dam at Eastwood Lake to U.S.
Hwy. 15
Booker Creek WS-IV;NSW 08/03/92 16-41-1-15-2-(5)From U.S. Hwy. 15 to Little Creek
Little Creek WS-IV;NSW,CA 08/03/92 16-41-1-15-(3)From a point 0.7 mile downstream of
Durham County SR 1110 to New
Hope Creek
Crooked Creek WS-V;NSW 08/03/92 16-41-1-16-(1)From source to a point 0.7 mile
upstream of mouth
Crooked Creek WS-IV;NSW,CA 08/03/92 16-41-1-16-(2)From a point 0.7 mile upstream of
mouth to New Hope Creek Arm of B.
Everett Jordan Lake
Northeast Creek WS-V;NSW 08/11/09 16-41-1-17-(0.3)From source to N.C. Hwy. 55
Northeast Creek WS-IV;NSW 08/03/92 16-41-1-17-(0.7)From N.C. Hwy. 55 to a point 0.5
mile downstream of Panther Creek
Burdens Creek WS-V;NSW 08/11/09 16-41-1-17-1-
(0.3)
From source to Durham County SR
2028
Burdens Creek WS-IV;NSW 08/03/92 16-41-1-17-1-
(0.7)
From Durham County SR 2028 to
Northeast Creek
Buck Branch WS-IV;NSW 08/03/92 16-41-1-17-1-1From source to Burdens Creek
Kit Creek WS-V;NSW 08/11/09 16-41-1-17-2-
(0.3)
From source to a point 1.3 miles
upstream of N.C. Hwy. 55
Kit Creek WS-IV;NSW 08/03/92 16-41-1-17-2-
(0.7)
From a point 1.3 miles upstream of
N.C. Hwy. 55 to Northeast Creek
Long Branch WS-IV;NSW 08/03/92 16-41-1-17-2-1From source to Kit Creek
Panther Creek WS-IV;NSW 08/03/92 16-41-1-17-3From source to New Hope Creek
Morris Branch WS-IV;NSW 08/03/92 16-41-1-17-3-1From source to Panther Creek
Nancy Branch WS-IV;NSW 08/03/92 16-41-1-17-3-2From source to Panther Creek
Northeast Creek WS-IV;NSW,CA 08/03/92 16-41-1-17-(4)From a point 0.5 mile downstream of
Panther Creek to New Hope Creek
Arm of B. Everett Jordan Lake
Indian Creek WS-IV;NSW 08/03/92 16-41-1-18-(1)From source to a point 0.4 mile
upstream of N.C. Hwy. 751
Indian Creek WS-IV;NSW,CA 08/03/92 16-41-1-18-(2)From a point 0.4 mile upstream of
N.C. Hwy. 751 to New Hope Creek
Arm of New Hope River Arm of B.
Everett Jordan Lake
Morgan Creek WS-II;HQW,NSW 08/03/92 16-41-2-(1)From source to a point 1.4 miles
downstream of N.C. Hwy. 54
Morgan Creek (University Lake)WS-II;HQW,NSW,
CA
08/03/92 16-41-2-(1.5)From a point 1.4 miles downstream
of N.C. Hwy. 54 to dam at University
Lake
Phils Creek WS-II;HQW,NSW 08/03/92 16-41-2-2-(0.3)From source to a point 0.2 mile
downstream of Orange County SR
1005
Phils Creek WS-II;HQW,NSW,
CA
08/03/92 16-41-2-2-(0.7)From a point 0.2 mile downstream of
Orange County SR 1005 to University
Lake, Morgan Creek
10
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1
FEMA'SCCOPERATIN6 TEr-HKCALPAMNER
This digital Flood Insurance Rate Map (FIRM) was produced through a unique
cooperative partnership between the State of North Carolina and the Federal
Emergency Management Agency (FEMA). The State of North Carolina has
implemented a long term approach to floodplain management to decrease the
costs associated with flooding. This is demonstrated by the State's commitment
to map flood hazard areas at the local level. As a part of this effort, the State of
North Carolina has joined in a Cooperating Technical State agreement with
FEMA to produce and maintain this digital FIRM.
FLOOD HAZARD INFORMATION NOTES TO USERS SCALE
SEE FIS REPORT FOR ZONE DESCRIPTIONS AND INDEX MAP
THE INFORMATION DEPICTED ON THIS MAP AND SUPPORTING
DOCUMENTATION ARE ALSO AVAILABLE IN DIGITAL FORMAT AT
HTTP://FPIS.NG.G0V/ F'P1S
SPECIAL FLOOD
HAZARD AREAS
OTHER AREAS OF
FLOOD HAZARD
OTHER
AREAS
GENERAL
STRU CTU R ES
OTHER
FEATURES
Without Base Flood Elevation (BFE)
Zane A, V, A99
With BFE or Depth Zone AL. AO, ars, VE, AR
Regulatory Floodway
. 0.2% Annual Chance Flood Hazard, Areas
of 1% Annual Chance Flood with Average
Depth Less Than One Foot or With Drainage
Areas of Less Than One Square Mile zone X
Future Conditions 1% Annual
Chance Flood Hazard Zone x
Area with Reduced Flood Risk due to Levee
See Notes zooX
Areas Determined to be Outside the
0.2%Q Annual Chance Floodplain zone x
------------- Channel, Culvert, or Storm Sewer
- Accredited or Provisionally Accredited
Levee, Dike, or Floodwall
I I i I l r I k I l l a l Nan -accredited Levee, Dike, Lir FloodwaII
BM5510 x
North Carolina Geodetic Survey bench mark
BM5510&
National Geodetic Survey bench mark
BM5510�
Contractor Est. NCFMP Survey bench mark
01 1'8-2—
Cross Sections with 1% Annual Chance
I
Water Surface Elevation (BFE)
(s - - - - - - Coastal Transect
- - - - - Coastal Transect Baseline
Profile Baseline
11 Hydrographic Feature
Limit of Study
Jurisdiction Bou
For information and questions about this map, available products associated with this FIRM including
historic versions of this FIRM, how to order products or the National Flood Insurance Program in general,
please call the FEMA Map Information eXchange at 1 -877 -FEMA -MAP (1-877-336-2627) or visit the FEMA Map
Service Center website at http:llmsc.fema.gov. An accompanying Flood Insurance Study report, Letter of Map
Revision (LOMB) or Letter of Map Amendment (LOMA) revising portions of this panel, and digital versions of this
FIRM may be available. Visit the North Carolina Floodplain Mapping Program website at http:llwww.ncflocdrnap
or contact the FEMA Map Service Center.
Communities annexing land on adjacent FIRM panels must obtain a current copy of the adjacent panel as well as
the current FIRM index. These may be ordered directly from the Map Service Center at the number listed above.
For community and countywide map dates refer to the Flood Insurance Study report for this jurisdiction.
To determine if flood insurance is available in the community, contact your Insurance agent or call the National
Flood Insurance Program at 1-800-638-6620.
Flood Insurance Study (FIS) means an examination, evaluation, and determination of flood hazards, corresponding
water surface elevations, flood hazard risk zones, and other flood data in a community issued by the North Carolina
Floodplain Mapping Program (NCFMP). The Flood Insurance Study (FIS) is comprised of the following products
used together: the Digital Flood Hazard Database, the Water Surface Elevation Rasters, the digitally derived,
autogenerated Flood Insurance Rate Map and the Flood Insurance Survey Report. AFlood Insurance Survey is a
compilation and presentation of flood risk data for specific watercourses, lakes, and coastal flood hazard areas within
a community. This report contains detailed flood elevation data, data tables and FIRM indices- When a flood study is
completed for the NFIP, the digital information, reports and maps are assembled into an FIS. Information shown on
this FIRM is provided In digital format by the NCFMP. Base map information shown on this FIRM was provided in
digital format by the NCFMP. The source of this information can be determined from the metadata available in the
digita€ FLOOD database and in the Technical Support Data Notebook (ISDN).
ACCREDITED LEVEE NOTES TO USERS: If an accredited levee note appears on this panel check with your local
community to obtain more information, such as the estimated level of protection provided (which may exceed the
1 -percent -annual -chance level) and Emergency Action Plan, on the levee system(s) shown as providing protection.
To mitigate flood risk in residual risk areas. property owners and residents are encouraged to consider flood
insurance and floodproofing or other protective measures. For more information on flood insurance, interested
parties should visit the FEMA Website at http:llwww.fema.gov/b usInessfnfip/index.shtm.
PROVISIONALLY ACCREDITED LEVEE NOTES TO USERS: If a Provisionally Accredited Levee (PAL) note
appears on this panel, check with your local community to obtain more information, such as the estimated level of
protection provided (which may exceed the 1 -percent -annual -chance level) and Emergency Action Plan, on the
Levee system(s) shown as providing protection. To maintain accreditation, the levee owner or community is
required to submit the data and documentation necessary to comply with Section 65.10 of the NFIP regulations.
If the community or owner does not provide the necessary data and documentation or if the data and documentation
provided indicates the levee system does not comply with Section 65.10 requirements, FEMA will revise the flood
hazard and risk information for this area to reflect de -accreditation of the levee system. To mitigate flood risk in
residual risk areas, property owners and residents are encouraged to consider flood insurance and floodproofing
or other protective measures. For more information on flood insurance, interested parties should visit the FEMA
Website at http:llwww.fema.gov/business/nfip/index.shtm.
LIMIT OF MODERATE WAVE ACTION NOTES TO USERS: For some coastal flooding zones the AE Zone
category has been divided by a Limit of Moderate Wave Action (LiMWA)- The LiMWA represents the approximate
landward limit of the 1.5 -foot breaking wave. The effects of wave hazards between the VE Zone and the JMWA
(or between the shoreline and the LiMWA for areas where VE Zones are not identified) will be similar to, but less
severe than those in the VE Zone.
Limit of Moderate Wave Action (LiMWA)
COASTAL BARRIER RESOURCES SYSTEM (CBRS) NOTE
This map may include approximate boundaries of the CBRS for informational purposes only. Flood insurance is not
available within CBRS areas for structures that are newly built or substantially improved on or after the date($)
indicated on the map. For more information see http:l/www.fws.gov/Gbra, the FIS Report, or call the U.S. Fish
and Wildlife Service Customer Service Center at 1 -900 -344 -WILD.
CBRS Area ti .; Otherwise Protected Area
Map Projection:
North Carolina State Plane Projection Feet (Zone 3200)
Datum: NAD 1983 (Horizontal), NAVID 1988 (Vertical)
1 inch = 500 feet 1:6,000
0 250 500 1,000
Feet
Meters
0 75 150 300
PANEL LO CATO R
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NORTH CAROLINA FLOODPLAIN MAPPING PROGRAM
NATIONAL FLOOD INSURANCE PROGRAM
FLOOD INSURANCE RATE MAP
NORTH CAROLINA
PANEL 9799
FEMA
Panel Contains:
COMMUNITY
CHAPEL HILL, TOWN OF
DURHAM, CITY OF
CID PANEL SUFFIX
370180 9799 L
370086 9799 L
VERSION NUMBER
2.3.3.2
MAP NUMBER
3710979900L
MAP REVISED
January 19, 2019

11/13/2018 Precipitation Frequency Data Server
NOAA Atlas 14, Volume 2, Version 3
' Location name: Chapel Hill, North Carolina, USA*
Latitude: 35.9331°, Longitude: -79.0213°
, vk�m
Elevation: 268.1 ft**
* source: ESRI Maps
"source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular i PF graphical i Maps & aerials
PF tabular
PDS -based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Average
recurrence interval (years)
1
2
5
10
25
50
100
200
500
1000
0.409
-O-.4-81---IF-O-.5-52---JF-O-.6-1
1
0.671
0.715
0.753
0.786
0.821
0.849
5 -min
1(0.374-0.447)11(0.441-0.525)
(0.506-0.602)
(0.559-0.666)
1(0.611-0.731)11(0.649-0.779)
(0.680-0.821)
(0.705-0.858)
(0.730-0.896)
(0.748-0.929)
0.653
-O-.7-69---JF-O-.8-84---JF-O-.9-77-
1.07
1.14
1.20
1.25
1.30
1.34
10 -min
1(0.598-0.714)11(0.705-0.840)1(0.810-0.964)1(0.894-1.07)
(0.974-1.17)
(1.03-1.24)
1 (1.08-1.30)
1 (1.12-1.36)
1 (1.16-1.42) 11
(1.18-1.46)
0.817
0.966
1.12
1.24
1.36
1.44
1.51
1.57
1.63
1.68
15 -min
(0.748-0.892)
(0.886-1.06)
(1.02-1.22)
(1.13-1.35)
1 (1.24-1.48) 11
(1.31-1.57)
1 (1.37-1.65)
1 (1.41-1.72)
1 (1.45-1.78) 11
(1.48-1.84)
2.72
1.12
1.34
1.59
1.79
2.01
2.17
2.32
2.45
2.60
30 -min
(1.02-1.22)
(1.22-1.46)
(1.46-1.73)
1 (1.83-2.19)
1 (1.97-2.37)
1 (2.09-2.53)
1 (2.19-2.67)
(2.31-2.84)
(2.40-2.97)
1.40
1.68
2.04
2.33
2.68
2.94
3.19
3A3
3.73
3.97
60 -min
(1.28-1.53)
(1.54-1.83)
(1.87-2.22)
1 (2.44-2.91)
1 (2.67-3.20) 11
(2.88-3.48)
1 (3.08-3.75)
(3.32-4.07)
(3.50-4.34)
F 5.25
1.67
2.01
2.47
2.85
3.31
3.68
4.04
4.40
4.87
2 -hr
(1.52-1.84)
(1.84-2.20)
(2.25-2.70)
(2.59-3.12)
(2.99-3.62)
(3.32-4.03)
(3.62-4.42)
1 (3.91-4.81)
1 (4.28-5.32) 11
(4.58-5.76)
1.78
2.14
2.64
3.06
3.59
4.03
4.45
4.89
5.47
5.97
3 -hr
(1.6 3-1.95)
(1.97-2.35)
(2.42-2.89)
(2.80-3.35)
(3.25-3.92)
(3.63-4.39)
(3.98-4.86)
1 (4.34-5.34)
(4.80-5.98) 11
(5.18-6.54)
2.14
2.57
3.17
3.69
4.35
4.91
5.46
6.04
6.81
7.48
6 -hr
(1.97-2.34)
(2.37-2.81)
(2.91-3.46)1
(3.38-4.02)
(3.96-4.73)
(4.43-5.33)
(4.89-5.93)
(5.35-6.55)
(5.95-7.40)
(6.45-8.14)
2.53
--505--]3.77
4.42
5.26
5.98
6.71
7.48
8.55
9.48
12 -hr
(2.34-2.76) 11
(2.81-3.32)
1 (4.05-4.80)
(4.78-5.69)
(5.39-6.45)
(5.99-7.23)
(6.60-8.06)
(7.41-9.21)
(8.09-10.2)
24 -hr
2.779616
3. 5 3?82
(4. 8 4677
(4.82-5.51)
(5.68-6.52)
(6.36-7.32)
(7.04-8.14)
(7.74-8.99)
(8.68-10.2)
(9.41-11.1)
3.46
4.17
5.17
5.93
6.96
7.77
8.59
9.43
10.6
11.5
2 -day
(3.24-3.70) 1(3.91-4.46)
(4.84-5.53)1
(5.55-6.34)
(6.48-7.44) 1(7.22-8.32)1
1 (6.80-7.81) 11
(7.95-9.22)
1 (8.69-10.1)
1 (9.70-11.4)
(10.5-12.4)
3 -day
3.66
(3.43-3.91) 11
4.40
(4.13-4.70)
5.43
1 (5.09-5.80)
--6.-23--]F-7-.30-77-8.-15-
1 (5.82-6.65)
(7.57-8.73)
9.02
1 (8.34-9.67)
9.90
1 (9.12-10.6)
11.1
1 (10.2-12.0) 11
12.1
(11.0-13.0)
4 -day
3.86
(3.62-4.13)
4.63
(4.34-4.95)
5.69
(5.33-6.07)
6.52
(6.10-6.97)
7.65
(7.12-8.18)
8.53
(7.92-9.14)
9.44
(8.73-10.1)
10.4
(9.55-11.1)
11.7
( 10.7-12.6)
12.7
( 11.5-13.7)
4.43
5.29
6.42
7.31
8.53
9.49
10.5
11.5
12.9
14.0
7 -day
(4.18-4.72)
(4.99-5.63)
1 (6.05-6.84)
(6.88-7.79)
(8.00-9.10)
(8.87-10.1)
(9.75-11.2)
(10.6-12.3)
(11.9-13.8)
(12.8-15.0)
14.9
5.04
--51.99--]7.19
8.13
9.39
10.4
11.4
12.4
13.8
10 -day
(4.76-5.36)
(5.65-6.36)
1 (7.65-8.64) 11
(8.82-9.99)
(9.72-11.1)
(10.6-12.2)
(11.6-13.3)
(12.8-14.8)
1 (13.7-16.0)
20 -day
(6.36-7.13)
7.51 8 40(8.85-9.92)
(9.92-11.1)
(11.3-12.8)
12.14- 4.1
13.16-15.5
14.17- 6.8
1612-18.7)
(17.18 0.2
9.85
11.4
12.7
14.3
15.6
16.8
18.1
19.7
21.0
30-day8.36
(7.93-8.85)
(9.32-10.4)
1 (13.5-15.1) 11
(14.6-16.5)
(15.7-17.8)
(16.9-19.2)
1 (18.3-21.0)
(19.5-22.4)
18.9
20.3
21.6
23.4
24.8
10.7
12.5
14.3
15.7
17.5
45 -day
(10.2-11.2)j
1 (16.6-18.4) 11
(17.9-19.9)
1 (19.1-21.4)
1 (20.3-22.8)
1 (21.9-24.8) 11
(23.1-26.3)
FI
-11 6-.18-7.6
60 -day
2.7
12.12-1$3.4
14.3- 5.6
16
17.1819.2
(19 2021.2
2 61
21?8- 4.2
23 04 5.7
24?6-27.5
25?8- 9.0
Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a
given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not
checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical
https:Hhdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=35.9331 &Ion=-79.0213&data=depth&units=english&series=pds 1/4

Storm Data Detailed
Report: WDF-17000
Element Details
33ID Notes
WDF-17000Label
1 yr-24 hr
1 yr-24 hrLabel min5.00Increment
years1Return Event min1,440.00End Time
min0.00Start Time CumulativeStorm Event Depth Type
1 yr-24 hr
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Time
(min)
0.0120.0090.0060.0030.0000.00
0.0270.0240.0210.0180.01525.00
0.0420.0390.0360.0330.03050.00
0.0570.0540.0510.0480.04575.00
0.0720.0690.0660.0630.060100.00
0.0870.0840.0810.0780.075125.00
0.1020.0990.0960.0930.090150.00
0.1160.1130.1100.1080.105175.00
0.1310.1280.1250.1220.119200.00
0.1460.1430.1400.1370.134225.00
0.1610.1580.1550.1520.149250.00
0.1760.1730.1700.1670.164275.00
0.1910.1880.1850.1820.179300.00
0.2060.2030.2000.1970.194325.00
0.2260.2200.2150.2120.209350.00
0.2530.2480.2420.2370.231375.00
0.2800.2750.2690.2640.258400.00
0.3070.3020.2960.2910.285425.00
0.3340.3290.3230.3180.313450.00
0.3610.3560.3500.3450.340475.00
0.3880.3830.3780.3720.367500.00
0.4200.4100.4050.3990.394525.00
0.4700.4600.4500.4400.430550.00
0.5200.5100.5000.4900.480575.00
0.5700.5600.5500.5400.530600.00
0.6180.6080.5990.5900.580625.00
0.6900.6680.6450.6360.627650.00
0.8450.7800.7580.7350.713675.00
1.6521.2431.0390.9740.910700.00
2.1152.0501.9861.9211.856725.00
2.2702.2482.2252.2032.180750.00
2.3432.3332.3242.3152.293775.00
2.3902.3802.3702.3612.352800.00
2.4402.4302.4202.4102.400825.00
2.4902.4802.4702.4602.450850.00
2.5402.5302.5202.5102.500875.00
2.5722.5662.5612.5552.550900.00
2/21/2019WDF-17000.ppc
C. BallardParks Apartments
Storm Data Detailed
Report: WDF-17000
1 yr-24 hr
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Time
(min)
2.5992.5932.5882.5832.577925.00
2.6262.6202.6152.6102.604950.00
2.6532.6482.6422.6372.631975.00
2.6802.6752.6692.6642.6581,000.00
2.7072.7022.6962.6912.6851,025.00
2.7342.7292.7232.7182.7131,050.00
2.7542.7512.7482.7452.7401,075.00
2.7692.7662.7632.7602.7571,100.00
2.7842.7812.7782.7752.7721,125.00
2.7992.7962.7932.7902.7871,150.00
2.8142.8112.8082.8052.8021,175.00
2.8292.8262.8232.8202.8171,200.00
2.8442.8412.8382.8352.8321,225.00
2.8582.8552.8532.8502.8471,250.00
2.8732.8702.8672.8642.8611,275.00
2.8882.8852.8822.8792.8761,300.00
2.9032.9002.8972.8942.8911,325.00
2.9182.9152.9122.9092.9061,350.00
2.9332.9302.9272.9242.9211,375.00
2.9482.9452.9422.9392.9361,400.00
(N/A)2.9602.9572.9542.9511,425.00
2 yr-24 hr
2 yr-24 hrLabel min5.00Increment
years2Return Event min1,440.00End Time
min0.00Start Time CumulativeStorm Event Depth Type
2 yr-24 hr
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Time
(min)
0.0140.0110.0070.0040.0000.00
0.0330.0290.0250.0220.01825.00
0.0510.0470.0430.0400.03650.00
0.0690.0650.0610.0580.05475.00
0.0870.0830.0790.0760.072100.00
0.1050.1010.0970.0940.090125.00
0.1230.1190.1160.1120.108150.00
0.1410.1370.1340.1300.126175.00
0.1590.1550.1520.1480.144200.00
0.1770.1730.1700.1660.163225.00
0.1950.1910.1880.1840.181250.00
0.2130.2090.2060.2020.199275.00
0.2310.2280.2240.2200.217300.00
0.2490.2460.2420.2380.235325.00
0.2730.2670.2600.2560.253350.00
0.3070.3000.2930.2870.280375.00
2/21/2019WDF-17000.ppc
C. BallardParks Apartments
Storm Data Detailed
Report: WDF-17000
2 yr-24 hr
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Time
(min)
0.3400.3330.3270.3200.313400.00
0.3730.3670.3600.3530.347425.00
0.4070.4000.3930.3870.380450.00
0.4400.4330.4270.4200.413475.00
0.4730.4670.4600.4530.447500.00
0.5120.5000.4930.4870.480525.00
0.5720.5600.5480.5360.524550.00
0.6310.6190.6080.5960.584575.00
0.6910.6790.6670.6550.643600.00
0.7480.7370.7260.7150.703625.00
0.8350.8080.7800.7690.758650.00
1.0240.9450.9180.8900.863675.00
1.9861.5051.2621.1831.104700.00
2.5462.4662.3872.3082.228725.00
2.7352.7082.6802.6532.625750.00
2.8232.8122.8012.7902.763775.00
2.8792.8672.8552.8442.833800.00
2.9392.9272.9152.9032.891825.00
2.9982.9862.9742.9632.951850.00
3.0583.0463.0343.0223.010875.00
3.0973.0903.0833.0773.070900.00
3.1303.1233.1173.1103.103925.00
3.1633.1573.1503.1433.137950.00
3.1973.1903.1833.1773.170975.00
3.2303.2233.2173.2103.2031,000.00
3.2633.2573.2503.2433.2371,025.00
3.2973.2903.2833.2773.2701,050.00
3.3213.3173.3143.3103.3031,075.00
3.3393.3353.3323.3283.3241,100.00
3.3573.3533.3503.3463.3431,125.00
3.3753.3713.3683.3643.3611,150.00
3.3933.3893.3863.3823.3791,175.00
3.4113.4083.4043.4003.3971,200.00
3.4293.4263.4223.4183.4151,225.00
3.4473.4443.4403.4363.4331,250.00
3.4653.4623.4583.4543.4511,275.00
3.4833.4803.4763.4733.4691,300.00
3.5013.4983.4943.4913.4871,325.00
3.5193.5163.5123.5093.5051,350.00
3.5383.5343.5303.5273.5231,375.00
3.5563.5523.5483.5453.5411,400.00
(N/A)3.5703.5663.5633.5591,425.00
10 yr-24 hr
10 yr-24 hrLabel min5.00Increment
years10Return Event min1,440.00End Time
2/21/2019WDF-17000.ppc
C. BallardParks Apartments
Storm Data Detailed
Report: WDF-17000
10 yr-24 hr
min0.00Start Time CumulativeStorm Event Depth Type
10 yr-24 hr
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Time
(min)
0.0150.0100.0050.0000.0000.00
0.0410.0360.0310.0260.02125.00
0.0670.0620.0570.0510.04650.00
0.0930.0870.0820.0770.07275.00
0.1180.1130.1080.1030.098100.00
0.1440.1390.1340.1280.123125.00
0.1700.1640.1590.1540.149150.00
0.1950.1900.1850.1800.175175.00
0.2210.2160.2110.2060.200200.00
0.2470.2420.2360.2310.226225.00
0.2720.2670.2620.2570.252250.00
0.2980.2930.2880.2830.278275.00
0.3240.3190.3130.3080.303300.00
0.3490.3440.3390.3340.329325.00
0.3800.3700.3650.3600.355350.00
0.4310.4210.4110.4000.390375.00
0.4820.4710.4610.4510.441400.00
0.5320.5220.5120.5020.492425.00
0.5830.5730.5630.5530.542450.00
0.6340.6230.6130.6030.593475.00
0.6840.6740.6640.6540.644500.00
0.7350.7250.7150.7050.694525.00
0.8230.8050.7880.7700.753550.00
0.9100.8930.8750.8580.840575.00
0.9980.9800.9630.9450.928600.00
1.0851.0681.0501.0331.015625.00
1.1981.1551.1381.1201.103650.00
1.4151.3721.3281.2851.242675.00
2.2141.8991.7781.6571.536700.00
3.5033.3823.2613.1392.825725.00
3.8753.8323.7883.7453.624750.00
4.0404.0234.0053.9623.918775.00
4.1284.1104.0934.0754.058800.00
4.2154.1984.1804.1634.145825.00
4.3034.2854.2684.2504.233850.00
4.3904.3734.3554.3384.320875.00
4.4554.4454.4354.4254.408900.00
4.5064.4964.4864.4764.466925.00
4.5574.5474.5374.5264.516950.00
4.6084.5974.5874.5774.567975.00
4.6584.6484.6384.6284.6181,000.00
4.7094.6994.6894.6784.6681,025.00
4.7604.7494.7394.7294.7191,050.00
2/21/2019WDF-17000.ppc
C. BallardParks Apartments
Storm Data Detailed
Report: WDF-17000
10 yr-24 hr
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Time
(min)
4.8004.7954.7904.7804.7701,075.00
4.8264.8214.8164.8114.8051,100.00
4.8524.8474.8414.8364.8311,125.00
4.8774.8724.8674.8624.8571,150.00
4.9034.8984.8934.8884.8831,175.00
4.9294.9244.9184.9134.9081,200.00
4.9544.9494.9444.9394.9341,225.00
4.9804.9754.9704.9654.9601,250.00
5.0065.0014.9964.9904.9851,275.00
5.0325.0265.0215.0165.0111,300.00
5.0575.0525.0475.0425.0371,325.00
5.0835.0785.0735.0685.0621,350.00
5.1095.1035.0985.0935.0881,375.00
5.1345.1295.1245.1195.1141,400.00
(N/A)5.1555.1505.1455.1391,425.00
25 yr-24 hr
25 yr-24 hrLabel min5.00Increment
years25Return Event min1,440.00End Time
min0.00Start Time CumulativeStorm Event Depth Type
25 yr-24 hr
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Time
(min)
0.0230.0180.0120.0060.0000.00
0.0530.0470.0410.0350.02925.00
0.0820.0760.0700.0640.05850.00
0.1110.1050.0990.0930.08875.00
0.1400.1340.1280.1230.117100.00
0.1690.1630.1580.1520.146125.00
0.1980.1930.1870.1810.175150.00
0.2280.2220.2160.2100.204175.00
0.2570.2510.2450.2390.233200.00
0.2860.2800.2740.2680.263225.00
0.3150.3090.3030.2980.292250.00
0.3440.3380.3330.3270.321275.00
0.3730.3680.3620.3560.350300.00
0.4030.3970.3910.3850.379325.00
0.4450.4330.4200.4140.408350.00
0.5080.4960.4830.4710.458375.00
0.5720.5590.5460.5340.521400.00
0.6350.6220.6100.5970.584425.00
0.6980.6850.6730.6600.648450.00
0.7610.7490.7360.7230.711475.00
0.8240.8120.7990.7870.774500.00
0.8960.8750.8620.8500.837525.00
2/21/2019WDF-17000.ppc
C. BallardParks Apartments
Storm Data Detailed
Report: WDF-17000
25 yr-24 hr
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Time
(min)
1.0020.9810.9590.9380.917550.00
1.1071.0861.0651.0441.023575.00
1.2131.1921.1711.1491.128600.00
1.3251.3021.2781.2551.234625.00
1.5001.4481.3951.3721.348650.00
1.8571.7101.6581.6051.553675.00
3.3122.6412.2972.1502.003700.00
4.2434.0973.9503.8033.657725.00
4.6004.5484.4954.4434.390750.00
4.7754.7524.7284.7054.653775.00
4.8874.8664.8454.8224.798800.00
4.9934.9724.9514.9294.908825.00
5.0985.0775.0565.0355.014850.00
5.2045.1835.1625.1415.119875.00
5.2765.2635.2505.2385.225900.00
5.3395.3265.3135.3015.288925.00
5.4025.3895.3775.3645.351950.00
5.4655.4535.4405.4275.415975.00
5.5285.5165.5035.4905.4781,000.00
5.5925.5795.5665.5545.5411,025.00
5.6555.6425.6295.6175.6041,050.00
5.6985.6925.6865.6805.6671,075.00
5.7275.7215.7155.7095.7031,100.00
5.7565.7505.7445.7385.7331,125.00
5.7855.7795.7735.7685.7621,150.00
5.8145.8085.8035.7975.7911,175.00
5.8435.8385.8325.8265.8201,200.00
5.8735.8675.8615.8555.8491,225.00
5.9025.8965.8905.8845.8781,250.00
5.9315.9255.9195.9135.9081,275.00
5.9605.9545.9485.9435.9371,300.00
5.9895.9835.9785.9725.9661,325.00
6.0186.0136.0076.0015.9951,350.00
6.0486.0426.0366.0306.0241,375.00
6.0776.0716.0656.0596.0531,400.00
(N/A)6.1006.0946.0886.0831,425.00
100 yr-24 hr
100 yr-24 hrLabel min5.00Increment
years100Return Event min1,440.00End Time
min0.00Start Time CumulativeStorm Event Depth Type
100 yr-24 hr
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Time
(min)
0.0250.0190.0120.0060.0000.00
2/21/2019WDF-17000.ppc
C. BallardParks Apartments
Storm Data Detailed
Report: WDF-17000
100 yr-24 hr
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Time
(min)
0.0560.0490.0430.0370.03125.00
0.0870.0800.0740.0680.06250.00
0.1170.1110.1050.0990.09375.00
0.1480.1420.1360.1300.124100.00
0.1790.1730.1670.1610.155125.00
0.2100.2040.1980.1920.185150.00
0.2410.2350.2290.2220.216175.00
0.2720.2660.2600.2530.247200.00
0.3030.2970.2900.2840.278225.00
0.3340.3280.3210.3150.309250.00
0.3650.3580.3520.3460.340275.00
0.3960.3890.3830.3770.371300.00
0.4260.4200.4140.4080.402325.00
0.4800.4620.4450.4390.433350.00
0.5670.5490.5320.5140.497375.00
0.6530.6360.6190.6010.584400.00
0.7400.7230.7050.6880.671425.00
0.8270.8100.7920.7750.757450.00
0.9140.8960.8790.8620.844475.00
1.0010.9830.9660.9480.931500.00
1.0981.0701.0531.0351.018525.00
1.2381.2101.1821.1541.126550.00
1.3791.3511.3231.2941.266575.00
1.5191.4911.4631.4351.407600.00
1.6781.6431.6091.5751.547625.00
1.9221.8511.7801.7461.712650.00
2.3922.2052.1342.0631.993675.00
4.0833.3302.9522.7652.578700.00
5.2085.0224.8354.6484.462725.00
5.6785.6085.5375.4665.395750.00
5.9225.8885.8545.8205.749775.00
6.0816.0536.0255.9915.957800.00
6.2216.1936.1656.1376.109825.00
6.3626.3346.3066.2776.249850.00
6.5026.4746.4466.4186.390875.00
6.5996.5826.5656.5476.530900.00
6.6866.6696.6526.6346.617925.00
6.7736.7566.7386.7216.704950.00
6.8606.8426.8256.8086.790975.00
6.9476.9296.9126.8956.8771,000.00
7.0337.0166.9996.9816.9641,025.00
7.1207.1037.0867.0687.0511,050.00
7.1747.1677.1617.1557.1381,075.00
7.2047.1987.1927.1867.1801,100.00
7.2357.2297.2237.2177.2111,125.00
7.2667.2607.2547.2487.2421,150.00
7.2977.2917.2857.2797.2721,175.00
2/21/2019WDF-17000.ppc
C. BallardParks Apartments
Storm Data Detailed
Report: WDF-17000
100 yr-24 hr
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Depth
(in)
Time
(min)
7.3287.3227.3167.3107.3031,200.00
7.3597.3537.3477.3407.3341,225.00
7.3907.3847.3777.3717.3651,250.00
7.4217.4157.4087.4027.3961,275.00
7.4527.4457.4397.4337.4271,300.00
7.4837.4767.4707.4647.4581,325.00
7.5137.5077.5017.4957.4891,350.00
7.5447.5387.5327.5267.5201,375.00
7.5757.5697.5637.5577.5511,400.00
(N/A)7.6007.5947.5887.5811,425.00
100 yr-24 hr 25 yr-24 hr 10 yr-24 hr 2 yr-24 hr
1 yr-24 hrDepth(in)8.750
7.500
6.250
5.000
3.750
2.500
1.250
0.000
Time (min)
1,400.001,200.001,000.00800.00600.00400.00200.000.00
2/21/2019WDF-17000.ppc
C. BallardParks Apartments
PARK APARTMENTS
WDF-17000
PRE-DEVELOPMENT
HYDROLOGIC CALCULATIONS
PARK APARTMENTS
WDF-17000
PRE-DEVELOPMENT HYDROLOGY
Summary of Results
C. BALLARD
5/2/2019
HYDROLOGY INPUT SUMMARY
Impervious Open Wooded Pond Total Impervious Open Wooded Pond Total
1 6.51 6.06 1.00 0.00 13.57 0.29 0.50 0.81 0.00 1.60 15.17 88 12.96
2 0.00 0.09 0.00 0.00 0.09 0.11 0.10 0.00 0.00 0.21 0.30 87 5.00
Totals =6.51 6.15 1.00 0.00 13.66 0.40 0.60 0.81 0.00 1.81 15.47
NUTRIENT INPUT SUMMARY
***Jordan/Falls Lake Stormwater Nitrogen and Phosphorus Tool
Land Use Area (sf)Area (ac)
Roof Area 80,221 1.84
Roadway Area 0 0.00
Parking/Driveway/Sidewalk 203,320 4.67
Wooded 43,635 1.00
Open 268,021 6.15
Pond 0 0.00
Total 595,197 13.66
2-YEAR / 24-HOUR VOLUME SUMMARY
Total On-Site Area =13.66 acres
Area Weighted On-site SCS CN =88
S =1.37
P (2-yr / 24-hour) =3.57 inches
Q* =2.33 inches
Total On-site Run-off Volume =2.65 acre-feet
=115,489 cf
Sub-basin ID Onsite Area [acres]Tc [min]Offsite Area [acres]Total Area
[acres]SCS CN
PARKS APARTMENTS
WDF-17000
PRE-DEVELOPMENT HYDROLOGY
Subbasin 1
C. BALLARD
5/2/2019
I. SCS CURVE NUMBERS
HSG Impervious Open Wooded
A 98 39 30
B 98 61 55
C 98 74 70
D 98 80 77
Assume:HSG 'A' =0.0%
HSG 'B' =0.0%
HSG 'C' =0.0%
HSG 'D' =100.0%
Cover Condition SCS CN
Impervious 98
Open 80
Wooded 77
II. PRE-DEVELOPMENT
A. Onsite Impervious Breakdown
Contributing Area Area [sf]Area [ac]
Roadway Area 0 0.00
Driveway / Parking Lot 155,275 3.56
Roof 80,221 1.84
Sidewalk / Patio 47,873 1.10
Other 0 0.00
Totals 283,369 6.51
B. Watershed Land Use Breakdown
Contributing Area SCS CN Area [sf]Area [acres]
Onsite impervious 98 283,369 6.51
Onsite open 80 264,167 6.06
Onsite wooded 77 43,635 1.00
Onsite pond 100 0 0.00
Offsite impervious 98 12,548 0.29
Offsite open 80 21,946 0.50
Offsite wooded 77 35,272 0.81
Offsite pond 100 0 0.00
Total area =15.17 acres
660,937 sf
Composite SCS CN =88
% Impervious =44.8%
Comments
-
Assume good condition
Assume good condition
-
-
Assume good condition
Assume good condition
-
Comments
-
Assume good condition
Assume good condition
PARKS APARTMENTS
WDF-17000
PRE-DEVELOPMENT HYDROLOGY
Subbasin 1
C. BALLARD
5/2/2019
C. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55).
Segment 1: Overland Flow Segment 2: Concentrated Flow
Length =100 ft Length =94 ft
Top Elev =293.00 ft Top Elev =286.00 ft
Bot Elev =286.00 ft Bot Elev =282.91 ft
Height =7 ft Height =3 ft
Slope =0.0700 ft/ft Slope =0.0329 ft/ft
Manning's n =0.24 dense grass Paved ? =No
P (2-year/24-hour) =3.57 inches (Chapel Hill, NC)Velocity =2.93 ft/sec
Segment Time =8.19 minutes Segment Time =0.54 minutes
Segment 3: Pipe Flow Segment 4: Channel Flow
Length =304 ft Length =126 ft
Top Elev =282.91 ft Top Elev =273.99 ft
Bot Elev =273.99 ft Bot Elev =267.21 ft
Height =8.92 ft Height =6.78 ft
Slope =0.0293 ft/ft Slope =0.0538 ft/ft
Manning's n =0.013 concrete pipe Manning's n =0.045 natural channel
Pipe Diameter=12.00 in Flow Area =2.00 sf (assume 2'W x 1'H)
Flow Area =0.79 sf Wetted Perimeter =4.00 lf (assume 2'W x 1'H)
Wetted Perimeter =3.14 lf (1 ft ID pipe)Channel Velocity =4.84 ft/sec
Channel Velocity =7.79 ft/sec Segment Time =0.43 minutes
Segment Time =0.65 minutes
Segment 5: Pipe Flow Segment 6: Channel Flow
Length =574 ft Length =490 ft
Top Elev =267.21 ft Top Elev =254.90 ft
Bot Elev =254.90 ft Bot Elev =250.00 ft
Height =12.31 ft Height =4.9 ft
Slope =0.0214 ft/ft Slope =0.0100 ft/ft
Manning's n =0.013 concrete pipe Manning's n =0.045 natural channel
Pipe Diameter=12.00 in Flow Area =24.00 sf (assume 6'W x 4'H)
Flow Area =0.79 sf Wetted Perimeter =14.00 lf (assume 6'W x 4'H)
Wetted Perimeter =3.14 lf (1 ft ID pipe)Channel Velocity =4.74 ft/sec
Channel Velocity =6.66 ft/sec Segment Time =1.72 minutes
Segment Time =1.44 minutes
Time of Concentration =12.96 minutes
SCS Lag Time =7.78 minutes (SCS Lag = 0.6* Tc)
Time Increment =2.26 minutes (= 0.29*SCS Lag)
D. 2-Year Runoff Volume Calculation
Pre-development runoff volume calculations are based upon the SCS Method. The equation for this method is as follows:
Q* = ((P-0.2*S)2)/ (P+0.8*S)
where,
Q* =Direct Runoff [inches]
S =Potential Abstraction => (1000 / SCS Curve Number) - 10
P =Accumulated Storm Rainfall [inches]
Per Town of Chapel Hill ordinance requirements, the increase in volume between pre- and post-development for the 2-year
24-hour storm shall be treated within the proposed stormwater management facility.
On-Site Area =13.57
On-site SCS CN =88
S =1.36
P (2-yr / 24-hour) =3.57
Q* =2.33
On-site Run-off Volume =2.64 acre-feet
=114,913 cf
PARKS APARTMENTS
WDF-17000
PRE-DEVELOPMENT HYDROLOGY
Subbasin 2
C. BALLARD
5/2/2019
I. SCS CURVE NUMBERS
HSG Impervious Open Wooded
A 98 39 30
B 98 61 55
C 98 74 70
D 98 80 77
Assume:HSG 'A' =0.0%
HSG 'B' =0.0%
HSG 'C' =0.0%
HSG 'D' =100.0%
Cover Condition SCS CN
Impervious 98
Open 80
Wooded 77
II. PRE-DEVELOPMENT
A. Onsite Impervious Breakdown
Contributing Area Area [sf]Area [ac]
Roadway Area 0 0.00
Driveway / Parking Lot 0 0.00
Roof 0 0.00
Sidewalk / Patio 172 0.00
Other 0 0.00
Totals 172 0.00
B. Watershed Land Use Breakdown
Contributing Area SCS CN Area [sf]Area [acres]
Onsite impervious 98 172 0.00
Onsite open 80 3,854 0.09
Onsite wooded 77 0 0.00
Onsite pond 100 0 0.00
Offsite impervious 98 4,873 0.11
Offsite open 80 4,170 0.10
Offsite wooded 77 0 0.00
Offsite pond 100 0 0.00
Total area =0.30 acres
13,069 sf
Composite SCS CN =87
% Impervious =38.6%
C. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55).
Time of Concentration =5.00 minutes
SCS Lag Time =3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment =0.87 minutes (= 0.29*SCS Lag)
D. 2-Year Runoff Volume Calculation
Pre-development runoff volume calculations are based upon the SCS Method. The equation for this method is as follows:
Q* = ((P-0.2*S)2)/ (P+0.8*S)
where,
Q* =Direct Runoff [inches]
S =Potential Abstraction => (1000 / SCS Curve Number) - 10
P =Accumulated Storm Rainfall [inches]
Per Town of Chapel Hill ordinance requirements, the increase in volume between pre- and post-development for the 2-year
24-hour storm shall be treated within the proposed stormwater management facility.
On-Site Area =0.09
On-site SCS CN =81
S =2.35
P (2-yr / 24-hour) =3.57
Q* =1.77
On-site Run-off Volume =0.01 acre-feet
=592 cf
Comments
-
Assume good condition
Assume good condition
Comments
-
-
Assume good condition
Assume good condition
-
-
Assume good condition
Assume good condition
Scenario: Pre-
Development
2/28/2019WDF-17000.ppc
C. BallardParks Apartments
FlexTable: Catchment
Table (WDF-17000.ppc)
Current Time: 0.00 min
NotesTime of
Concentration
(min)
SCS CNArea
(ft²)
Outflow NodeLabel
PRE12.9688.0660,937POA 1SUB 1
PRE5.0087.013,069POA-2SUB 2
5/2/2019WDF-17000.ppc
C. BallardParks Apartments
Subsection: Master Network Summary
Catchments Summary
Peak Flow
(ft³/s)
Time to Peak
(min)
Hydrograph
Volume
(ft³)
Return
Event
(years)
ScenarioLabel
34.20726.0097,8861Pre-Dev 1yr-24hrSUB 1
43.80726.00128,1002Pre-Dev 2 yr-24 hrSUB 1
72.32726.00259,45325Pre-Dev 25 yr-24 hrSUB 1
0.90721.001,8541Pre-Dev 1yr-24hrSUB 2
1.16721.002,4422Pre-Dev 2 yr-24 hrSUB 2
1.91721.005,01925Pre-Dev 25 yr-24 hrSUB 2
Node Summary
Peak Flow
(ft³/s)
Time to Peak
(min)
Hydrograph
Volume
(ft³)
Return
Event
(years)
ScenarioLabel
34.20726.0097,8861Pre-Dev 1yr-24hrPOA 1
43.80726.00128,1002Pre-Dev 2 yr-24 hrPOA 1
72.32726.00259,45325Pre-Dev 25 yr-24 hrPOA 1
0.90721.001,8541Pre-Dev 1yr-24hrPOA-2
1.16721.002,4422Pre-Dev 2 yr-24 hrPOA-2
1.91721.005,01925Pre-Dev 25 yr-24 hrPOA-2
5/2/2019WDF-17000.ppc
C. BallardParks Apartments
CLIENT
REVISIONS
PROJECT NO.
FILENAME
CHECKED BY
DRAWN BY
SCALE
DATE 02. 28. 2019
N0.DATE
\\johnrmcadams.com\dfsrt1\Projects\WDF\WDF-17000\Storm\Form District Permit\Current Drawings\WDF17000-PRE.dwg, 5/2/2019 11:16:30 AM, Ballard, CraigThe John R. McAdams Company, Inc.
2905 Meridian Parkway
Durham, NC 27713
phone [phone]
fax [phone]
license number: C-0293
www.mcadamsco.com
PARK APARTMENTSFORM DISTRICT PERMIT1250 EPHESUS CHURCH ROADCHAPEL HILL, NORTH CAROLINA, 27517SHEET
PLAN INFORMATION
WOODFIELD INVESTMENTS
11425 HORSEMAN'S TRAIL
RALEIGH, NC 27613
PHONE: [phone]
FINAL DRAWING - NOT RELEASED FOR CONSTRUCTION
WDF-17000
1 05. 03. 2019 PER CHAPEL HILL AND OWASA COMMENTS
SUB 1
AREA = 15.17 ac.S1S2TC PAT
H
S3
POA 1 WDF17000-PRE
KEG
SCB
1" = 50'
PRE DEVELOPMENT
HYDROLOGY MAP
PRE
GRAPHIC SCALE
0 25 50 100
1 inch = 50 ft.S4
S5
E
P
H
E
S
U
S

C
H
U
R
C
H

R
D
FRANC
E
S
S
T
REGULATORY
FLOODWAY
POA 2
SUB 2
AREA = 0.30 ac.
1% ANNUAL CHANCE
FLOODPLAIN
1% ANNUAL CHANCE
FLOODPLAIN
PROPERTY LINE
AREA = 13.66 ac.
BOO
K
E
R

C
R
E
E
K
50' JORDAN LAKE
WATERSHED BUFFERS6
PARK APARTMENTS
WDF-17000
POST-DEVELOPMENT
HYDROLOGIC CALCULATIONS
PARK APARTMENTS
WDF-17000
POST-DEVELOPMENT HYDROLOGY
Summary of Results
C. BALLARD, EI
6/19/2019
HYDROLOGY INPUT SUMMARY
Impervious Open Wooded Pond Total Impervious Open Wooded Pond Total
1A - Bypass 3.31 0.88 0.09 0.00 4.28 0.30 0.04 0.00 0.00 0.34 4.63 94 5.00
1B - Bypass 0.00 2.19 0.00 0.00 2.19 0.00 0.00 0.00 0.00 0.00 2.19 80 13.34
1 - to SCM A 1.09 0.50 0.00 0.00 1.59 0.00 0.00 0.00 0.00 0.00 1.59 92 5.00
1- to SCM B 4.52 1.08 0.00 0.00 5.59 0.38 0.29 0.78 0.00 1.45 7.05 92 5.00
Totals =8.92 4.66 0.09 0.00 13.66 0.68 0.33 0.78 0.00 1.80 15.46
ONSITE IMPERVIOUS SUMMARY
Contributing Area Area [sf]Area [ac]
Roof 132,389 3.04
Road 80,801 1.85
Parking/Driveway/Sidewalk 175,436 4.03
Wooded 3,791 0.09
Open 202,780 4.66
Pond 0 0.00
Totals 595,197 13.66
2-YEAR / 24-HOUR VOLUME SUMMARY
Total On-Site Area =13.66 acres
Area Weighted On-site SCS CN =92
S =0.90
P (2-yr / 24-hour) =3.57 inches
Q* =2.68 inches
Total On-site Run-off Volume =3.05 acre-feet
=132,823 cf
Tc [min]Offsite Area [acres]Total Area
[acres]SCS CNSub-basin ID Onsite Area [acres]
PARK APARTMENTS
WDF-17000
POST-DEVELOPMENT HYDROLOGY
Subbasin 1A - Bypass
C. BALLARD, EI
6/19/2019
I. SCS CURVE NUMBERS
HSG Impervious Open Wooded
A 98 39 30
B 98 61 55
C 98 74 70
D 98 80 77
Assume:HSG 'A' =0.0%
HSG 'B' =0.0%
HSG 'C' =0.0%
HSG 'D' =100.0%
Cover Condition SCS CN
Impervious 98
Open 80
Wooded 77
II. POST-DEVELOPMENT
A. Onsite Impervious Breakdown
Contributing Area Area [sf]Area [acres]
Roof 34,990 0.80
Road 52,253 1.20
Parking/Driveway/Sidewalk 57,111 1.31
Totals 144,354 3.31
B. Watershed Breakdown
Contributing Area SCS CN Area [sf]Area [acres]
Onsite impervious 98 144,354 3.31
Onsite open 80 38,378 0.88
Onsite wooded 77 3,791 0.09
Onsite pond 100 0 0.00
Offsite impervious 98 13,052 0.30
Offsite open 80 1,936 0.04
Offsite wooded 77 0 0.00
Offsite pond 100 0 0.00
Total area =4.63 acres
201,511 sq.ft.
Composite SCS CN =94
% Impervious =78.1%
C. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55).
Time of Concentration =5.00 minutes
SCS Lag Time =3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment =0.87 minutes (= 0.29*SCS Lag)
D. Runoff Volume Calculations
Pre-development runoff volume calculations are based upon the SCS Method. The equation for this method is as follows:
Q* = ((P-0.2*S)2) / (P+0.8*S)
where,
Q* =Direct Runoff [inches]
S =Potential Abstraction => (1000 / SCS Curve Number) - 10
P =Accumulated Storm Rainfall [inches]
On-Site Area =4.28 acres
On-site SCS CN =94
S =0.65
P (2-yr / 24-hour) =3.57 inches (Chapel Hill, NC)
Q* =2.89 inches
Onsite Run-off Volume =1.03 acre-feet
=44929 cf
Comments
-
Assume good condition
Assume good condition
-
-
Assume good condition
Comments
Assume good condition
-
-
Assume good condition
Assume good condition
PARK APARTMENTS
WDF-17000
POST-DEVELOPMENT HYDROLOGY
Subbasin 1B - Bypass
C. BALLARD, EI
6/19/2019
I. SCS CURVE NUMBERS
HSG Impervious Open Wooded
A 98 39 30
B 98 61 55
C 98 74 70
D 98 80 77
Assume:HSG 'A' =0.0%
HSG 'B' =0.0%
HSG 'C' =0.0%
HSG 'D' =100.0%
Cover Condition SCS CN
Impervious 98
Open 80
Wooded 77
II. POST-DEVELOPMENT
A. Onsite Impervious Breakdown
Contributing Area Area [sf]Area [acres]
Roof 0 0.00
Road 0 0.00
Parking/Driveway/Sidewalk 0 0.00
Totals 0 0.00
B. Watershed Breakdown
Contributing Area SCS CN Area [sf]Area [acres]
Onsite impervious 98 0 0.00
Onsite open 80 95,600 2.19
Onsite wooded 77 0 0.00
Onsite pond 100 0 0.00
Offsite impervious 98 0 0.00
Offsite open 80 0 0.00
Offsite wooded 77 0 0.00
Offsite pond 100 0 0.00
Total area =2.19 acres
95,600 sq.ft.
Composite SCS CN =80
% Impervious =0.0%
Comments
-
Assume good condition
Assume good condition
Comments
-
-
Assume good condition
Assume good condition
-
-
Assume good condition
Assume good condition
PARK APARTMENTS
WDF-17000
POST-DEVELOPMENT HYDROLOGY
Subbasin 1B - Bypass
C. BALLARD, EI
6/19/2019
C. Time of Concentration Information
Time of concentration is calculated using the SCS Segmental Approach (TR-55).
Segment 1: Overland Flow Segment 2: Concentrated Flow
Length =100 ft Length =367 ft
Top Elev =268.00 ft Top Elev =266.00 ft
Bot Elev =266.00 ft Bot Elev =262.00 ft
Height =2 ft Height =4 ft
Slope =0.0200 ft/ft Slope =0.0109 ft/ft
Manning's n =0.15 short grass Paved ? =No
P (2-year/24-hour) =3.57 inches (Chapel Hill, NC)Velocity =1.68 ft/sec
Segment Time =9.28 minutes Segment Time =3.63 minutes
Segment 3: Pipe Flow Segment 4: Channel Flow
Length =178 ft Length =47 ft
Top Elev =258.00 ft Top Elev =252.00 ft
Bot Elev =252.00 ft Bot Elev =250.00 ft
Height =6 ft Height =2 ft
Slope =0.0337 ft/ft Slope =0.0426 ft/ft
Manning's n =0.013 concrete pipe Manning's n =0.045 natural channel
Pipe Diameter=18.00 in Flow Area =3.00 sf (assume 3'W x 1'H)
Flow Area =1.77 sf Wetted Perimeter =5.00 lf (assume 3'W x 1'H)
Wetted Perimeter =4.71 lf (1 ft ID pipe)Channel Velocity =4.86 ft/sec
Channel Velocity =10.94 ft/sec Segment Time =0.16 minutes
Segment Time =0.27 minutes
Time of Concentration =13.34 minutes
SCS Lag Time =8.00 minutes (SCS Lag = 0.6* Tc)
Time Increment =2.32 minutes (= 0.29*SCS Lag)
D. Runoff Volume Calculations
Pre-development runoff volume calculations are based upon the SCS Method. The equation for this method is as follows:
Q* = ((P-0.2*S)2) / (P+0.8*S)
where,
Q* =Direct Runoff [inches]
S =Potential Abstraction => (1000 / SCS Curve Number) - 10
P =Accumulated Storm Rainfall [inches]
On-Site Area =2.19 acres
On-site SCS CN =80
S =2.50
P (2-yr / 24-hour) =3.57 inches (Chapel Hill, NC)
Q* =1.69 inches
Onsite Run-off Volume =0.31 acre-feet
=13480 cf
PARK APARTMENTS
WDF-17000
POST-DEVELOPMENT HYDROLOGY
Subbasin 1 - to SCM A
C. BALLARD, EI
6/19/2019
I. SCS CURVE NUMBERS
HSG Impervious Open Wooded
A 98 39 30
B 98 61 55
C 98 74 70
D 98 80 77
Assume:HSG 'A' =0.0%
HSG 'B' =0.0%
HSG 'C' =0.0%
HSG 'D' =100.0%
Cover Condition SCS CN
Impervious 98
Open 80
Wooded 77
II. POST-DEVELOPMENT
A. Onsite Impervious Breakdown
Contributing Area Area [sf]Area [acres]
Roof 18,177 0.42
Road 0 0.00
Parking/Driveway/Sidewalk 29,261 0.67
Totals 47,438 1.09
B. Watershed Breakdown
Contributing Area SCS CN Area [sf]Area [acres]
Onsite impervious 98 47,438 1.09
Onsite open 80 21,974 0.50
Onsite wooded 77 0 0.00
Onsite pond 100 0 0.00
Offsite impervious 98 0 0.00
Offsite open 80 0 0.00
Offsite wooded 77 0 0.00
Offsite pond 100 0 0.00
Total area =1.59 acres
69,412 sq.ft.
Composite SCS CN =92
% Impervious =68.3%
C. Time of Concentration Information
Time of concentration is assumed to be 5 minutes.
Time of Concentration =5.00 minutes
SCS Lag Time =3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment =0.87 minutes (= 0.29*SCS Lag)
D. Runoff Volume Calculations
Pre-development runoff volume calculations are based upon the SCS Method. The equation for this method is as follows:
Q* = ((P-0.2*S)2) / (P+0.8*S)
where,
Q* =Direct Runoff [inches]
S =Potential Abstraction => (1000 / SCS Curve Number) - 10
P =Accumulated Storm Rainfall [inches]
On-Site Area =1.59 acres
On-site SCS CN =92
S =0.83
P (2-yr / 24-hour) =3.57 inches (Chapel Hill, NC)
Q* =2.73 inches
Onsite Run-off Volume =0.36 acre-feet
=15810 cf
-
Assume good condition
Assume good condition
-
-
Assume good condition
Assume good condition
Comments
-
Assume good condition
Assume good condition
Comments
-
PARK APARTMENTS
WDF-17000
POST-DEVELOPMENT HYDROLOGY
Subbasin 1 - to SCM B
C. BALLARD, EI
6/19/2019
I. SCS CURVE NUMBERS
HSG Impervious Open Wooded
A 98 39 30
B 98 61 55
C 98 74 70
D 98 80 77
Assume:HSG 'A' =0.0%
HSG 'B' =0.0%
HSG 'C' =0.0%
HSG 'D' =100.0%
Cover Condition SCS CN
Impervious 98
Open 80
Wooded 77
II. POST-DEVELOPMENT
A. Onsite Impervious Breakdown
Contributing Area Area [sf]Area [acres]
Roof 79,222 1.82
Road 28,548 0.66
Parking/Driveway/Sidewalk 89,064 2.04
Totals 196,834 4.52
B. Watershed Breakdown
Contributing Area SCS CN Area [sf]Area [acres]
Onsite impervious 98 196,834 4.52
Onsite open 80 46,828 1.08
Onsite wooded 77 0 0.00
Onsite pond 100 0 0.00
Offsite impervious 98 16,604 0.38
Offsite open 80 12,610 0.29
Offsite wooded 77 34,106 0.78
Offsite pond 100 0 0.00
Total area =7.05 acres
306,982 sq.ft.
Composite SCS CN =92
% Impervious =69.5%
C. Time of Concentration Information
Time of concentration is assumed to be 5 minutes.
Time of Concentration =5.00 minutes
SCS Lag Time =3.00 minutes (SCS Lag = 0.6* Tc)
Time Increment =0.87 minutes (= 0.29*SCS Lag)
D. Runoff Volume Calculations
Pre-development runoff volume calculations are based upon the SCS Method. The equation for this method is as follows:
Q* = ((P-0.2*S)2) / (P+0.8*S)
where,
Q* =Direct Runoff [inches]
S =Potential Abstraction => (1000 / SCS Curve Number) - 10
P =Accumulated Storm Rainfall [inches]
On-Site Area =5.59 acres
On-site SCS CN =95
S =0.58
P (2-yr / 24-hour) =3.57 inches (Chapel Hill, NC)
Q* =2.96 inches
Onsite Run-off Volume =1.38 acre-feet
=60098 cf
Comments
-
Assume good condition
Assume good condition
Comments
-
-
Assume good condition
Assume good condition
-
-
Assume good condition
Assume good condition
Scenario: Post-
Development
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
FlexTable: Catchment
Table (WDF-17000.ppc)
Current Time: 0.00 min
NotesTime of
Concentration
(min)
SCS CNArea (User Defined)
(ft²)
Outflow NodeLabel
POST13.3480.095,600POA 1SUB 1B Bypass
POST5.0092.069,412SCM ASUB 1 to SCM A
POST5.0094.0201,511POA 1SUB 1A Bypass
POST5.0092.0306,982SCM BSUB 1 to SCM B
6/19/2019WDF-17000.ppc
C. BallardParks Apartments
Subsection: Master Network Summary
Catchments Summary
Peak Flow
(ft³/s)
Time to Peak
(min)
Hydrograph
Volume
(ft³)
Return
Event
(years)
ScenarioLabel
3.26727.009,6821Post-Dev 1yr-24hrSUB 1B Bypass
4.51727.0013,4322Post-Dev 2 yr-24 hrSUB 1B Bypass
8.67727.0030,75525Post-Dev 25 yr-24 hrSUB 1B Bypass
5.90721.0012,2691Post-Dev 1yr-24hrSUB 1 to SCM A
7.27721.0015,6232Post-Dev 2 yr-24 hrSUB 1 to SCM A
11.00721.0029,86525Post-Dev 25 yr-24 hrSUB 1 to SCM A
18.34721.0038,7771Post-Dev 1yr-24hrSUB 1A Bypass
22.25721.0048,7142Post-Dev 2 yr-24 hrSUB 1A Bypass
32.72721.0090,52925Post-Dev 25 yr-24 hrSUB 1A Bypass
26.09721.0054,2631Post-Dev 1yr-24hrSUB 1 to SCM B
32.13721.0069,0932Post-Dev 2 yr-24 hrSUB 1 to SCM B
48.67721.00132,08325Post-Dev 25 yr-24 hrSUB 1 to SCM B
Node Summary
Peak Flow
(ft³/s)
Time to Peak
(min)
Hydrograph
Volume
(ft³)
Return
Event
(years)
ScenarioLabel
34.04722.00110,4911Post-Dev 1yr-24hrPOA 1
41.53722.00142,1372Post-Dev 2 yr-24 hrPOA 1
70.33724.00278,15125Post-Dev 25 yr-24 hrPOA 1
26.09721.0054,2631Post-Dev 1yr-24hrSCM B
32.13721.0069,0932Post-Dev 2 yr-24 hrSCM B
48.67721.00132,08325Post-Dev 25 yr-24 hrSCM B
Pond Summary
Maximum
Pond Storage
(ft³)
Maximum
Water
Surface
Elevation
(ft)
Peak Flow
(ft³/s)
Time to Peak
(min)
Hydrograph
Volume
(ft³)
Return
Event
(years)
ScenarioLabel
(N/A)(N/A)31.99721.0066,5321Post-Dev 1yr-
24hr
SCM A (IN)
17,539259.2516.42728.0062,0321Post-Dev 1yr-
24hr
SCM A
(OUT)
(N/A)(N/A)39.40721.0084,7162Post-Dev 2 yr-
24 hr
SCM A (IN)
21,082259.7419.64728.0079,9912Post-Dev 2 yr-
24 hr
SCM A
(OUT)
(N/A)(N/A)59.67721.00161,94925Post-Dev 25 yr
-24 hr
SCM A (IN)
29,331260.8138.42726.00156,86825Post-Dev 25 yr
-24 hr
SCM A
(OUT)
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
GRAPHIC SCALE
0 25 50 100
1 inch = 50 ft.
WDF17000-POST
KEG
BMS
1" = 50'
SUB 1 to SCM A
AREA = 1.59 ac.
POA 1
POST DEVELOPMENT
HYDROLOGY MAP
POST-DA
FRANCE
S
S
T
REGULATORY
FLOODWAY
1% ANNUAL CHANCE
FLOODPLAIN
1% ANNUAL CHANCE
FLOODPLAIN
SUB 1A BYPASS
AREA = 4.63 ac.
SUB 1B BYPASS
AREA = 2.19 ac.
ELLIOT
T
R
D
(VARIA
B
L
E
WI
D
T
H
P
U
B
LI
C
R
/
W
)
DESIGN
E
D
B
Y
KI
M
L
E
Y
H
O
R
N
EPHESUS CHURCH RD.
(VARIABLE WIDTH PUBLIC R/W)
DESIGNED BY KIMLEY HORN
STREET "B"(60' PUBLIC R/
W)
S
T
R
E
E
T

"
A
"
(
6
0
'

P
U
B
L
I
C

R
/W
)
SCM A
DRY DETENTION
POND SCM B
CMP / STORMFILTER SYSTEM
BOOK
ER

CR
E
E
K
PROPERTY LINE
AREA = 13.66 ac.
SUB 1 to SCM B
AREA = 7.05 ac.
50' JORDAN LAKE
WATERSHED BUFFERS1S2TC PATHS3S4CLIENT
REVISIONS
PROJECT NO.
FILENAME
CHECKED BY
DRAWN BY
SCALE
DATE 02. 28. 2019
N0.DATE
X:\Projects\WDF\WDF-17000\Storm\Form District Permit\Current Drawings\WDF17000-POST.dwg, 6/20/2019 8:27:21 AM, Saur, BrieanaThe John R. McAdams Company, Inc.
2905 Meridian Parkway
Durham, NC 27713
phone [phone]
fax [phone]
license number: C-0293
www.mcadamsco.com
PARK APARTMENTSFORM DISTRICT PERMIT1250 EPHESUS CHURCH ROADCHAPEL HILL, NORTH CAROLINA, 27517SHEET
PLAN INFORMATION
WOODFIELD INVESTMENTS
11425 HORSEMAN'S TRAIL
RALEIGH, NC 27613
PHONE: [phone]
FINAL DRAWING - NOT RELEASED FOR CONSTRUCTION
WDF-17000
1 05. 03. 2019 PER CHAPEL HILL AND OWASA COMMENTS
2 06. 20. 2019 PER CHAPEL HILL AND OWASA COMMENTS
06-18-2019
PARK APARTMENTS
WDF-17000
STORMWATER CONTROL MEASURE ‘A’
DESIGN CALCULATIONS
PARK APARTMENTS
WDF-17000
STORMWATER CONTROL MEASURE 'A'
Stage-Storage Function
C. BALLARD
5/1/2019
STAGE-STORAGE FUNCTION
Average Incremental Accumulated Estimated
Contour Contour Contour Contour Stage
Contour Stage Area Area Volume Volume w/ S-S Fxn
(feet)(feet)(SF)(SF)(CF)(CF)(feet)
256.50 0.00 5,584
258.00 1.50 6,455 6020 9029 9029 1.51
260.00 3.50 7,573 7014 14028 23057 3.45
262.00 5.50 8,835 8204 16408 39465 5.55
1.131517164 8.643956893
5675.743759
KS =5676
b =1.1315
y = 5675.7x1.1315
R² = 0.9997
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
0.00 1.00 2.00 3.00 4.00 5.00 6.00Storage(CF)Stage (feet)
Storage vs. Stage
PARK APARTMENTS
WDF-17000
STORMWATER CONTROL MEASURE 'A'
Detained Volume Calculations
C. BALLARD
5/1/2019
ASSOCIATED DEPTH IN POND
Volume Detained =4409 cf.
Stage / Storage Data:
Ks =5676
b =1.132
Zo =256.50
Calculated values:
Depth in Basin =0.80 ft
=9.60 inches
Elevation =257.30 ft
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A
Return Event: 1 yearsSubsection: Elevation-Area Volume Curve
Volume (Total)
(ft³)
Volume
(ft³)
A1+A2+sqr
(A1*A2)
(ft²)
Area
(ft²)
Planimeter
(ft²)
Elevation
(ft)
0005,5840.000256.50
9,0219,02118,0436,4550.000258.00
23,03414,01321,0207,5730.000260.00
39,42616,39224,5888,8350.000262.00
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A
Return Event: 1 yearsSubsection: Outlet Input Data
Requested Pond Water Surface Elevations
ft256.50Minimum (Headwater)
ft0.10Increment (Headwater)
ft262.00Maximum (Headwater)
Outlet Connectivity
E2
(ft)
E1
(ft)
OutfallDirectionOutlet IDStructure Type
258.30257.30CulvertForwardWeir - 1cRectangular Weir
258.30257.30CulvertForwardWeir - 1bRectangular Weir
258.30257.30CulvertForwardWeir - 1aRectangular Weir
262.00258.30CulvertForwardOrifice - 1Orifice-Area
262.00260.20CulvertForwardRiserInlet Box
262.00256.50CulvertForwardOrifice -
2yr Volume
Orifice-Circular
262.00256.50TWForwardCulvertCulvert-Circular
(N/A)(N/A)TailwaterTailwater Settings
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A
Return Event: 1 yearsSubsection: Outlet Input Data
Structure ID: Riser
Structure Type: Inlet Box
1Number of Openings
ft260.20Elevation
ft²25.000Orifice Area
0.6Orifice Coefficient
ft20.00Weir Length
(ft^0.5)/s3.00Weir Coefficient
1.0K Reverse
0.0Manning's n
0.0Kev, Charged Riser
FalseWeir Submergence
FalseOrifice H to crest
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A
Return Event: 1 yearsSubsection: Outlet Input Data
Structure ID: Culvert
Structure Type: Culvert-Circular
1Number of Barrels
in30.00Diameter
ft26.00Length
ft26.00Length (Computed Barrel)
ft/ft0.019Slope (Computed)
Outlet Control Data
0.013Manning's n
0.5Ke
0.0Kb
0.5Kr
ft0.00Convergence Tolerance
Inlet Control Data
Form 1Equation Form
0.0098K
2.0000M
0.0398C
0.6700Y
0.0T1 ratio (HW/D)
1.3T2 ratio (HW/D)
-0.5Slope Correction Factor
Use unsubmerged inlet control 0 equation below T1 elevation.
Use submerged inlet control 0 equation above T2 elevation
In transition zone between unsubmerged and submerged inlet
control,
interpolate between flows at T1 & T2...
ft256.50T1 Elevation ft³/s27.16T1 Flow
ft259.74T2 Elevation ft³/s31.05T2 Flow
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A
Return Event: 1 yearsSubsection: Outlet Input Data
Structure ID: Orifice - 1
Structure Type: Orifice-Area
3Number of Openings
ft257.30Elevation
ft²1.500Orifice Area
ft258.30Top Elevation
ft257.80Datum Elevation
0.6Orifice Coefficient
Structure ID: Weir - 1a
Structure Type: Rectangular Weir
1Number of Openings
ft257.30Elevation
ft1.50Weir Length
(ft^0.5)/s3.00Weir Coefficient
Structure ID: Weir - 1b
Structure Type: Rectangular Weir
1Number of Openings
ft257.30Elevation
ft1.50Weir Length
(ft^0.5)/s3.00Weir Coefficient
Structure ID: Weir - 1c
Structure Type: Rectangular Weir
1Number of Openings
ft257.30Elevation
ft1.50Weir Length
(ft^0.5)/s3.00Weir Coefficient
Structure ID: Orifice - 2yr Volume
Structure Type: Orifice-Circular
1Number of Openings
ft256.50Elevation
in4.00Orifice Diameter
0.6Orifice Coefficient
Structure ID: TW
Structure Type: TW Setup, DS Channel
Free OutfallTailwater Type
Convergence Tolerances
30Maximum Iterations
ft0.01Tailwater Tolerance
(Minimum)
ft0.50Tailwater Tolerance
(Maximum)
ft0.01Headwater Tolerance
(Minimum)
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A
Return Event: 1 yearsSubsection: Outlet Input Data
Convergence Tolerances
ft0.50Headwater Tolerance
(Maximum)
ft³/s0.001Flow Tolerance (Minimum)
ft³/s10.000Flow Tolerance (Maximum)
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A
Return Event: 1 yearsSubsection: Composite Rating Curve
Composite Outflow Summary
Contributing StructuresConvergence Error
(ft)
Tailwater Elevation
(ft)
Flow
(ft³/s)
Water Surface
Elevation
(ft)
(no Q: Weir - 1c,Weir -
1b,Weir - 1a,Orifice -
1,Riser,Orifice - 2yr
Volume,Culvert)
0.00(N/A)0.00256.50
Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 1,Riser)
0.00(N/A)0.02256.60
Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 1,Riser)
0.00(N/A)0.05256.70
Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 1,Riser)
0.00(N/A)0.13256.80
Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 1,Riser)
0.00(N/A)0.18256.90
Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 1,Riser)
0.00(N/A)0.22257.00
Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 1,Riser)
0.00(N/A)0.25257.10
Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 1,Riser)
0.00(N/A)0.28257.20
Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 1,Riser)
0.00(N/A)0.31257.30
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 2yr
Volume,Culvert (no Q:
Orifice - 1,Riser)
0.00(N/A)0.71257.40
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 2yr
Volume,Culvert (no Q:
Orifice - 1,Riser)
0.00(N/A)1.44257.50
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 2yr
Volume,Culvert (no Q:
Orifice - 1,Riser)
0.00(N/A)2.37257.60
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 2yr
Volume,Culvert (no Q:
Orifice - 1,Riser)
0.00(N/A)3.28257.70
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A
Return Event: 1 yearsSubsection: Composite Rating Curve
Composite Outflow Summary
Contributing StructuresConvergence Error
(ft)
Tailwater Elevation
(ft)
Flow
(ft³/s)
Water Surface
Elevation
(ft)
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 2yr
Volume,Culvert (no Q:
Orifice - 1,Riser)
0.00(N/A)4.11257.80
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 2yr
Volume,Culvert (no Q:
Orifice - 1,Riser)
0.00(N/A)4.94257.90
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 2yr
Volume,Culvert (no Q:
Orifice - 1,Riser)
0.00(N/A)5.79258.00
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 2yr
Volume,Culvert (no Q:
Orifice - 1,Riser)
0.00(N/A)6.67258.10
Weir - 1c,Weir - 1b,Weir -
1a,Orifice - 2yr
Volume,Culvert (no Q:
Orifice - 1,Riser)
0.00(N/A)7.56258.20
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)9.55258.30
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)10.29258.40
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)11.04258.50
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)11.78258.60
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)12.52258.70
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)13.24258.80
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)13.96258.90
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)14.67259.00
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A
Return Event: 1 yearsSubsection: Composite Rating Curve
Composite Outflow Summary
Contributing StructuresConvergence Error
(ft)
Tailwater Elevation
(ft)
Flow
(ft³/s)
Water Surface
Elevation
(ft)
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)15.38259.10
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)16.05259.20
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)16.74259.30
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)17.41259.40
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)18.08259.50
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)18.75259.60
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)19.39259.70
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)20.03259.80
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)20.65259.90
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)21.26260.00
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)21.88260.10
Orifice - 1,Orifice - 2yr
Volume,Culvert (no Q:
Weir - 1c,Weir - 1b,Weir -
1a,Riser)
0.00(N/A)22.47260.20
Orifice - 1,Riser,Orifice -
2yr Volume,Culvert (no
Q: Weir - 1c,Weir -
1b,Weir - 1a)
0.00(N/A)24.12260.30
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A
Return Event: 1 yearsSubsection: Composite Rating Curve
Composite Outflow Summary
Contributing StructuresConvergence Error
(ft)
Tailwater Elevation
(ft)
Flow
(ft³/s)
Water Surface
Elevation
(ft)
Orifice - 1,Riser,Orifice -
2yr Volume,Culvert (no
Q: Weir - 1c,Weir -
1b,Weir - 1a)
0.00(N/A)26.64260.40
Orifice - 1,Riser,Orifice -
2yr Volume,Culvert (no
Q: Weir - 1c,Weir -
1b,Weir - 1a)
0.00(N/A)29.66260.50
Orifice - 1,Riser,Orifice -
2yr Volume,Culvert (no
Q: Weir - 1c,Weir -
1b,Weir - 1a)
0.00(N/A)32.96260.60
Orifice - 1,Riser,Orifice -
2yr Volume,Culvert (no
Q: Weir - 1c,Weir -
1b,Weir - 1a)
0.00(N/A)35.72260.70
Orifice - 1,Riser,Orifice -
2yr Volume,Culvert (no
Q: Weir - 1c,Weir -
1b,Weir - 1a)
0.00(N/A)38.31260.80
Orifice - 1,Riser,Orifice -
2yr Volume,Culvert (no
Q: Weir - 1c,Weir -
1b,Weir - 1a)
0.00(N/A)40.35260.90
Riser,Culvert (no Q: Weir
- 1c,Weir - 1b,Weir -
1a,Orifice - 1,Orifice - 2yr
Volume)
0.00(N/A)41.53261.00
Riser,Culvert (no Q: Weir
- 1c,Weir - 1b,Weir -
1a,Orifice - 1,Orifice - 2yr
Volume)
0.00(N/A)42.25261.10
Riser,Culvert (no Q: Weir
- 1c,Weir - 1b,Weir -
1a,Orifice - 1,Orifice - 2yr
Volume)
0.00(N/A)42.96261.20
Riser,Culvert (no Q: Weir
- 1c,Weir - 1b,Weir -
1a,Orifice - 1,Orifice - 2yr
Volume)
0.00(N/A)43.67261.30
Riser,Culvert (no Q: Weir
- 1c,Weir - 1b,Weir -
1a,Orifice - 1,Orifice - 2yr
Volume)
0.00(N/A)44.35261.40
Riser,Culvert (no Q: Weir
- 1c,Weir - 1b,Weir -
1a,Orifice - 1,Orifice - 2yr
Volume)
0.00(N/A)45.03261.50
Riser,Culvert (no Q: Weir
- 1c,Weir - 1b,Weir -
1a,Orifice - 1,Orifice - 2yr
Volume)
0.00(N/A)45.69261.60
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A
Return Event: 1 yearsSubsection: Composite Rating Curve
Composite Outflow Summary
Contributing StructuresConvergence Error
(ft)
Tailwater Elevation
(ft)
Flow
(ft³/s)
Water Surface
Elevation
(ft)
Riser,Culvert (no Q: Weir
- 1c,Weir - 1b,Weir -
1a,Orifice - 1,Orifice - 2yr
Volume)
0.00(N/A)46.35261.70
Riser,Culvert (no Q: Weir
- 1c,Weir - 1b,Weir -
1a,Orifice - 1,Orifice - 2yr
Volume)
0.00(N/A)47.00261.80
Riser,Culvert (no Q: Weir
- 1c,Weir - 1b,Weir -
1a,Orifice - 1,Orifice - 2yr
Volume)
0.00(N/A)47.64261.90
Riser,Culvert (no Q: Weir
- 1c,Weir - 1b,Weir -
1a,Orifice - 1,Orifice - 2yr
Volume)
0.00(N/A)48.27262.00
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 1 yr-24 hrLabel: SCM A (IN)
Return Event: 1 yearsSubsection: Level Pool Pond Routing Summary
Infiltration
No InfiltrationInfiltration Method
(Computed)
Initial Conditions
ft256.50Elevation (Water Surface,
Initial)
ft³0Volume (Initial)
ft³/s0.00Flow (Initial Outlet)
ft³/s0.00Flow (Initial Infiltration)
ft³/s0.00Flow (Initial, Total)
min1.00Time Increment
Inflow/Outflow Hydrograph Summary
ft³/s31.99Flow (Peak In)min721.00Time to Peak (Flow, In)
ft³/s16.42Flow (Peak Outlet)min728.00Time to Peak (Flow, Outlet)
ft259.25Elevation (Water Surface,
Peak)
ft³17,539Volume (Peak)
Mass Balance (ft³)
ft³0Volume (Initial)
ft³66,532Volume (Total Inflow)
ft³0Volume (Total Infiltration)
ft³62,032Volume (Total Outlet
Outflow)
ft³4,481Volume (Retained)
ft³-19Volume (Unrouted)
%0.0Error (Mass Balance)
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 2 yr-24 hrLabel: SCM A (IN)
Return Event: 2 yearsSubsection: Level Pool Pond Routing Summary
Infiltration
No InfiltrationInfiltration Method
(Computed)
Initial Conditions
ft256.50Elevation (Water Surface,
Initial)
ft³0Volume (Initial)
ft³/s0.00Flow (Initial Outlet)
ft³/s0.00Flow (Initial Infiltration)
ft³/s0.00Flow (Initial, Total)
min1.00Time Increment
Inflow/Outflow Hydrograph Summary
ft³/s39.40Flow (Peak In)min721.00Time to Peak (Flow, In)
ft³/s19.64Flow (Peak Outlet)min728.00Time to Peak (Flow, Outlet)
ft259.74Elevation (Water Surface,
Peak)
ft³21,082Volume (Peak)
Mass Balance (ft³)
ft³0Volume (Initial)
ft³84,716Volume (Total Inflow)
ft³0Volume (Total Infiltration)
ft³79,991Volume (Total Outlet
Outflow)
ft³4,703Volume (Retained)
ft³-21Volume (Unrouted)
%0.0Error (Mass Balance)
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 10 yr-24 hrLabel: SCM A (IN)
Return Event: 10 yearsSubsection: Level Pool Pond Routing Summary
Infiltration
No InfiltrationInfiltration Method
(Computed)
Initial Conditions
ft256.50Elevation (Water Surface,
Initial)
ft³0Volume (Initial)
ft³/s0.00Flow (Initial Outlet)
ft³/s0.00Flow (Initial Infiltration)
ft³/s0.00Flow (Initial, Total)
min1.00Time Increment
Inflow/Outflow Hydrograph Summary
ft³/s53.45Flow (Peak In)min726.00Time to Peak (Flow, In)
ft³/s31.46Flow (Peak Outlet)min732.00Time to Peak (Flow, Outlet)
ft260.55Elevation (Water Surface,
Peak)
ft³27,327Volume (Peak)
Mass Balance (ft³)
ft³0Volume (Initial)
ft³132,894Volume (Total Inflow)
ft³0Volume (Total Infiltration)
ft³127,911Volume (Total Outlet
Outflow)
ft³4,951Volume (Retained)
ft³-32Volume (Unrouted)
%0.0Error (Mass Balance)
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 25 yr-24 hrLabel: SCM A (IN)
Return Event: 25 yearsSubsection: Level Pool Pond Routing Summary
Infiltration
No InfiltrationInfiltration Method
(Computed)
Initial Conditions
ft256.50Elevation (Water Surface,
Initial)
ft³0Volume (Initial)
ft³/s0.00Flow (Initial Outlet)
ft³/s0.00Flow (Initial Infiltration)
ft³/s0.00Flow (Initial, Total)
min1.00Time Increment
Inflow/Outflow Hydrograph Summary
ft³/s59.67Flow (Peak In)min721.00Time to Peak (Flow, In)
ft³/s38.42Flow (Peak Outlet)min726.00Time to Peak (Flow, Outlet)
ft260.81Elevation (Water Surface,
Peak)
ft³29,331Volume (Peak)
Mass Balance (ft³)
ft³0Volume (Initial)
ft³161,949Volume (Total Inflow)
ft³0Volume (Total Infiltration)
ft³156,868Volume (Total Outlet
Outflow)
ft³5,045Volume (Retained)
ft³-36Volume (Unrouted)
%0.0Error (Mass Balance)
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 100 yr-24 hrLabel: SCM A (IN)
Return Event: 100 yearsSubsection: Level Pool Pond Routing Summary
Infiltration
No InfiltrationInfiltration Method
(Computed)
Initial Conditions
ft256.50Elevation (Water Surface,
Initial)
ft³0Volume (Initial)
ft³/s0.00Flow (Initial Outlet)
ft³/s0.00Flow (Initial Infiltration)
ft³/s0.00Flow (Initial, Total)
min1.00Time Increment
Inflow/Outflow Hydrograph Summary
ft³/s68.08Flow (Peak In)min721.00Time to Peak (Flow, In)
ft³/s43.15Flow (Peak Outlet)min726.00Time to Peak (Flow, Outlet)
ft261.23Elevation (Water Surface,
Peak)
ft³32,789Volume (Peak)
Mass Balance (ft³)
ft³0Volume (Initial)
ft³208,366Volume (Total Inflow)
ft³0Volume (Total Infiltration)
ft³203,217Volume (Total Outlet
Outflow)
ft³5,111Volume (Retained)
ft³-38Volume (Unrouted)
%0.0Error (Mass Balance)
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 100 yr-24 hrLabel: SCM A - WC
Return Event: 100 yearsSubsection: Outlet Input Data
Requested Pond Water Surface Elevations
ft256.50Minimum (Headwater)
ft0.10Increment (Headwater)
ft262.00Maximum (Headwater)
Outlet Connectivity
E2
(ft)
E1
(ft)
OutfallDirectionOutlet IDStructure Type
258.30257.30CulvertForwardWeir - 1bRectangular Weir
258.30257.30CulvertForwardWeir - 1aRectangular Weir
262.00258.30CulvertForwardOrifice - 1Orifice-Area
262.00260.20CulvertForwardRiserInlet Box
258.30257.30CulvertForwardWeir - 1cRectangular Weir
262.00256.50TWForwardCulvertCulvert-Circular
(N/A)(N/A)TailwaterTailwater Settings
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 100 yr-24 hrLabel: SCM A - WC
Return Event: 100 yearsSubsection: Outlet Input Data
Structure ID: Riser
Structure Type: Inlet Box
1Number of Openings
ft260.20Elevation
ft²25.000Orifice Area
0.6Orifice Coefficient
ft20.00Weir Length
(ft^0.5)/s3.00Weir Coefficient
1.0K Reverse
0.0Manning's n
0.0Kev, Charged Riser
FalseWeir Submergence
FalseOrifice H to crest
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 100 yr-24 hrLabel: SCM A - WC
Return Event: 100 yearsSubsection: Outlet Input Data
Structure ID: Culvert
Structure Type: Culvert-Circular
1Number of Barrels
in30.00Diameter
ft26.00Length
ft26.00Length (Computed Barrel)
ft/ft0.019Slope (Computed)
Outlet Control Data
0.013Manning's n
0.5Ke
0.0Kb
0.5Kr
ft0.00Convergence Tolerance
Inlet Control Data
Form 1Equation Form
0.0098K
2.0000M
0.0398C
0.6700Y
1.2T1 ratio (HW/D)
1.3T2 ratio (HW/D)
-0.5Slope Correction Factor
Use unsubmerged inlet control 0 equation below T1 elevation.
Use submerged inlet control 0 equation above T2 elevation
In transition zone between unsubmerged and submerged inlet
control,
interpolate between flows at T1 & T2...
ft259.38T1 Elevation ft³/s27.16T1 Flow
ft259.74T2 Elevation ft³/s31.05T2 Flow
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 100 yr-24 hrLabel: SCM A - WC
Return Event: 100 yearsSubsection: Outlet Input Data
Structure ID: Orifice - 1
Structure Type: Orifice-Area
3Number of Openings
ft257.30Elevation
ft²1.500Orifice Area
ft258.30Top Elevation
ft257.80Datum Elevation
0.6Orifice Coefficient
Structure ID: Weir - 1a
Structure Type: Rectangular Weir
1Number of Openings
ft257.30Elevation
ft1.50Weir Length
(ft^0.5)/s3.00Weir Coefficient
Structure ID: Weir - 1b
Structure Type: Rectangular Weir
1Number of Openings
ft257.30Elevation
ft1.50Weir Length
(ft^0.5)/s3.00Weir Coefficient
Structure ID: Weir - 1c
Structure Type: Rectangular Weir
1Number of Openings
ft257.30Elevation
ft1.50Weir Length
(ft^0.5)/s3.00Weir Coefficient
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 100 yr-24 hrLabel: SCM A - WC
Return Event: 100 yearsSubsection: Composite Rating Curve
Composite Outflow Summary
Contributing StructuresConvergence Error
(ft)
Tailwater Elevation
(ft)
Flow
(ft³/s)
Water Surface
Elevation
(ft)
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00256.50
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00256.60
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00256.70
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00256.80
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00256.90
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00257.00
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00257.10
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00257.20
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00257.30
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00257.40
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00257.50
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00257.60
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00257.70
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00257.80
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00257.90
(no Q: Weir - 1b,Weir -
1a,Orifice - 1,Riser,Weir -
1c,Culvert)
0.00258.000.00258.00
Weir - 1b,Weir - 1a,Weir
- 1c,Culvert (no Q: Orifice
- 1,Riser)
0.00258.003.91258.10
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 100 yr-24 hrLabel: SCM A - WC
Return Event: 100 yearsSubsection: Composite Rating Curve
Composite Outflow Summary
Contributing StructuresConvergence Error
(ft)
Tailwater Elevation
(ft)
Flow
(ft³/s)
Water Surface
Elevation
(ft)
Weir - 1b,Weir - 1a,Weir
- 1c,Culvert (no Q: Orifice
- 1,Riser)
0.00258.005.66258.20
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.008.51258.30
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.009.79258.40
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0010.89258.50
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0011.83258.60
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0012.65258.70
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0013.21258.80
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0013.85258.90
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0014.55259.00
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0015.24259.10
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0015.91259.20
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0016.58259.30
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0017.25259.40
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0017.91259.50
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0018.56259.60
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0019.19259.70
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0019.81259.80
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 100 yr-24 hrLabel: SCM A - WC
Return Event: 100 yearsSubsection: Composite Rating Curve
Composite Outflow Summary
Contributing StructuresConvergence Error
(ft)
Tailwater Elevation
(ft)
Flow
(ft³/s)
Water Surface
Elevation
(ft)
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0020.44259.90
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0021.04260.00
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0021.66260.10
Orifice - 1,Culvert (no Q:
Weir - 1b,Weir -
1a,Riser,Weir - 1c)
0.00258.0022.25260.20
Orifice - 1,Riser,Culvert
(no Q: Weir - 1b,Weir -
1a,Weir - 1c)
0.00258.0023.90260.30
Orifice - 1,Riser,Culvert
(no Q: Weir - 1b,Weir -
1a,Weir - 1c)
0.00258.0026.43260.40
Orifice - 1,Riser,Culvert
(no Q: Weir - 1b,Weir -
1a,Weir - 1c)
0.00258.0029.46260.50
Orifice - 1,Riser,Culvert
(no Q: Weir - 1b,Weir -
1a,Weir - 1c)
0.00258.0032.80260.60
Orifice - 1,Riser,Culvert
(no Q: Weir - 1b,Weir -
1a,Weir - 1c)
0.00258.0035.63260.70
Orifice - 1,Riser,Culvert
(no Q: Weir - 1b,Weir -
1a,Weir - 1c)
0.00258.0038.27260.80
Orifice - 1,Riser,Culvert
(no Q: Weir - 1b,Weir -
1a,Weir - 1c)
0.00258.0040.32260.90
Riser,Culvert (no Q: Weir
- 1b,Weir - 1a,Orifice -
1,Weir - 1c)
0.00258.0041.53261.00
Riser,Culvert (no Q: Weir
- 1b,Weir - 1a,Orifice -
1,Weir - 1c)
0.00258.0042.25261.10
Riser,Culvert (no Q: Weir
- 1b,Weir - 1a,Orifice -
1,Weir - 1c)
0.00258.0042.96261.20
Riser,Culvert (no Q: Weir
- 1b,Weir - 1a,Orifice -
1,Weir - 1c)
0.00258.0043.67261.30
Riser,Culvert (no Q: Weir
- 1b,Weir - 1a,Orifice -
1,Weir - 1c)
0.00258.0044.35261.40
Riser,Culvert (no Q: Weir
- 1b,Weir - 1a,Orifice -
1,Weir - 1c)
0.00258.0045.03261.50
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 100 yr-24 hrLabel: SCM A - WC
Return Event: 100 yearsSubsection: Composite Rating Curve
Composite Outflow Summary
Contributing StructuresConvergence Error
(ft)
Tailwater Elevation
(ft)
Flow
(ft³/s)
Water Surface
Elevation
(ft)
Riser,Culvert (no Q: Weir
- 1b,Weir - 1a,Orifice -
1,Weir - 1c)
0.00258.0045.69261.60
Riser,Culvert (no Q: Weir
- 1b,Weir - 1a,Orifice -
1,Weir - 1c)
0.00258.0046.35261.70
Riser,Culvert (no Q: Weir
- 1b,Weir - 1a,Orifice -
1,Weir - 1c)
0.00258.0047.00261.80
Riser,Culvert (no Q: Weir
- 1b,Weir - 1a,Orifice -
1,Weir - 1c)
0.00258.0047.64261.90
Riser,Culvert (no Q: Weir
- 1b,Weir - 1a,Orifice -
1,Weir - 1c)
0.00258.0048.27262.00
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
Parks Apartments
Storm Event: 100 yr-24 hrLabel: SCM A (IN)
Return Event: 100 yearsSubsection: Level Pool Pond Routing Summary
Infiltration
No InfiltrationInfiltration Method
(Computed)
Initial Conditions
ft257.30Elevation (Water Surface,
Initial)
ft³4,649Volume (Initial)
ft³/s0.00Flow (Initial Outlet)
ft³/s0.00Flow (Initial Infiltration)
ft³/s0.00Flow (Initial, Total)
min1.00Time Increment
Inflow/Outflow Hydrograph Summary
ft³/s68.08Flow (Peak In)min721.00Time to Peak (Flow, In)
ft³/s43.29Flow (Peak Outlet)min726.00Time to Peak (Flow, Outlet)
ft261.25Elevation (Water Surface,
Peak)
ft³32,956Volume (Peak)
Mass Balance (ft³)
ft³4,649Volume (Initial)
ft³208,366Volume (Total Inflow)
ft³0Volume (Total Infiltration)
ft³203,889Volume (Total Outlet
Outflow)
ft³9,094Volume (Retained)
ft³-32Volume (Unrouted)
%0.0Error (Mass Balance)
5/1/2019WDF-17000.ppc
C. BallardParks Apartments
PARK APARTMENTS
WDF-17000
STORMWATER CONTORL MEASURE 'A'
Anti-Flotation Block Calculations
K.GARCIA, PE
6/10/2019
RISER ANTI-FLOTATION CALCULATION
Input Data ==>
Safety Factor:
Safety factor to use =1.15 (recommend 1.15 or higher)
Concrete:
Concrete unit weight =142.0 PCF Note: NC Products lists unit wt. of
manhole concrete at 142 PCF.
Riser:
Inside height of Riser =3.70 feet
Inside length of riser =5.00 feet
Inside width of riser =5.00 feet
Wall thickness of riser =6.00 inches
Base thickness of riser =6.00 inches
Base length of riser =6.00 feet
Base width of riser =6.00 feet
Openings:
Total Orifice Area = 4.587 SF
OD of barrel exiting manhole =38.50 inches
Size of drain pipe (if present) =6.0 inches
Trash Rack:
Bottom Length = 8.40 feet
Bottom Width = 8.40 feet
Top Length = 2.10 feet
Top Width = 2.10 feet
Height = 2.00 feet
Trash Rack water displacement =61.74 CF
Concrete Present in Riser Structure ==>
Total amount of concrete:
Base of Riser =18.00 CF
Riser Walls =40.70 CF
Adjust for openings:
Opening for Orifices = 2.29 CF
Opening for barrel =4.04 CF
Opening for drain pipe =0.10 CF
Total Concrete present, adjusted for openings =52.266 CF
Weight of concrete present =7,422 lbs
PARK APARTMENTS
WDF-17000
STORMWATER CONTORL MEASURE 'A'
Anti-Flotation Block Calculations
K.GARCIA, PE
6/10/2019
Amount of water displaced by Riser Structure ==>
Displacement by concrete =52.27 CF
Displacement by open air in riser =92.50 CF
Displacement by trash rack =61.74 CF
Total water displaced by riser/barrel structure =206.51 CF
Weight of water displaced =12,886 lbs
Calculate size of base for riser assembly ==>
Length =9.00 feet
Width =9.00 feet
Thickness =18 inches
Concrete Present =121.50 CF
Check validity of base as designed ==>
Total Water Displaced =310.01 CF
Total Concrete Present =173.77 CF
Total Water Displaced =19,344 lbs
Total Concrete Present =24,675 lbs
Actual safety factor =1.28 OK
Results of design ==>
Base length =9.00 feet
Base width =9.00 feet
Base Thickness =18.00 inches
CY of concrete total in base =4.50 CY
Concrete unit weight in added base >=142.0 PCF
PARK APARTMENTS
WDF-17000
STORMWATER CONTORL MEASURE 'A'
Anti-Flotation Block Calculations
K.GARCIA, PE
6/10/2019
II. CALCULATION FOR RISER ANTI-FLOTATION STEEL
Input Data ==>
Anti-Floatation Block Length =9.0 feet
Anti-Floatation Block Width =9.0 feet
Anti-Floatation Block Thickness =18 inches
Asteel to Aconcrete Ratio =0.0020 (recommend 0.0018 or higher)
Cross-Section Calculations==>
Cross-Section Area* =13.50 SF
Minimum Steel Area Required =0.027 SF
3.89 SI
*Note: Assumes a "square" x-sec (L and W same)
Rebar Calculations ==>
Bar Size 4 5 6 7 8
Diameter (inches)0.500 0.625 0.750 0.875 1.000
X-Sec Area (SI)0.196 0.307 0.442 0.601 0.785
Minimum Number of Bars Each X-Sec 20 13 9 7 5
Project Date 5/1/2019
Project No.Designer SCB
Outlet ID
Flow, Q10-yr 31.46 cfs
Slope, S 1.92 %
Pipe Diameter, Do 30 inches
Pipe Diameter, Do 2.5 feet
Number of pipes 1
Pipe separation 0 feet
Manning's n 0.013
Zone from graph above =3
Outlet pipe diameter 30 in.Length =20.0 ft.
Outlet flowrate 31.5 cfs Width =7.5 ft.
Outlet velocity 11.9 ft/sec Stone diameter =13 in.
Material =Class I Thickness =22 in.
Zone Material Diameter Thickness Length Width
1 Class A 3 9 4 x D(o)3 x D(o)
2 Class B 6 22 6 x D(o)3 x D(o)
3 Class I 13 22 8 x D(o)3 x D(o)
4 Class I 13 22 8 x D(o)3 x D(o)
5 Class II 23 27 10 x D(o)3 x D(o)
6 Class II 23 27 10 x D(o)3 x D(o)
7
1. Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual
2. Outlet velocity based on full-flow velocity
DESIGN OF RIPRAP OUTLET PROTECTION WORKSHEET
PARK APARTMENTS
WDF-17000
SCM A
Special study required
11.9 ft/sec
0
5
10
15
20
25
0 1 2 3 4 5 6 7 8 9 10Velocity(ft/sec)Pipe diameter (ft)
Figure 8.06.b.1
Zone 1 Zone 2
Zone 3
Zone 4
Zone 5
Zone 6 Zone 7
SCM A - Rip Rap Outlet Protection Design5/1/2019
PARK APARTMENTS
WDF-17000
STORMWATER CONTROL MEASURE ‘B’
DESIGN CALCULATIONS
PARK APARTMENTS
WDF-17000
STORM FILTER DESIGN
SCM B
K.GARCIA, PE
6/19/2019
Determination of Water Quality Volume (WQV)
Note: The following design calculations are based upon requirements from the 2007 NCDENR BMP Manual.
where,
WQV= water quality volume (CF)
RV = 0.05+0.009(I) where I is percent impervious cover
A = area in acres
P = rainfall (in inches)
Input data:
Total area, A =7.05 acres
Impervious area =4.90 acres
Percent impervious cover, I =69.5 %
Rainfall, P =1.0 inches
Calculated values:
RV =0.68
WQV =0.40 acre-ft
=17287 cf.
Sizing is based upon the adjusted water quality volume, WQV adj (75% of the total WQV).
WQVadj =12965 cf.(Volume contained between the sedimentation chamber and the
sand filter - above the sand)
WQvol Storage Pipe Size Estimate
Number of pipes =3
Pipe diameter =60 inch
Pipe length =220 feet
Number of Cartridges =32
WQV = (P)(RV)(A)/12 x 43,560
©2008 CONTECH Stormwater Solutions
contechstormwater.com 1 of 1
Design Engineer:LRS Blue Cells =Input
Date 5/1/2019 Black Cells =Calculation
Site Information
Project Name Park Apartments REV1
Project State North Carolina
Project Location Chapel Hill
Drainage Area, Ad 7.05 ac
Impervious Area, Ai 4.88 ac
Pervious Area, Ap 2.17
% Impervious 69%
Runoff Coefficient, Rv 0.67 =0.05+0.9*(Ai/Ad)
Water Quality Volume Calculations
Design storm rainfall depth, Rd 1.0 in
Water quality volume, WQV 17222.5 ft3 =Ad*Rv*Rd*(43560/12)
Storage Component Calculations
Capture 75% of WQV 12916.9 ft3 =0.75*WQV
Pretreatment credit (estimated or calculated), %pre 30%
Mass loading calculations
Mean Annual Rainfall, P 46 in
Agency required % removal 85%
Percent Runoff Capture (% capture)90%
Mean Annual Runoff,Vt 713,013 ft3 =P*Ad*Rv*(43560/12)*%capture
Event Mean Concentration of Pollutant, EMC 70.0 mg/l (Suggestion: Use 60 for residential, 70 for Commercial, 100 for Industrial)
Annual Mass Load, Mtotal 3113.95 lbs =EMC*Vt*(28.3)*(0.000001)*(2.2046)
Filter System
Filtration brand StormFilter
Cartridge height 27 in
Cartridge Quantity Calculation
Mass removed by pretreatment system, Mpre 934 lbs =Mtotal * %removal
Mass load to filters after pretreatment, Mpass1 2180 lbs =Mtotal - Mpre
Estimate the required filter efficiency, Efilter 79%=1+(%removal - 1)/(1 - %pre)
Mass to be captured by filters, Mfilter 1713 lbs =Mpass1 * Efilter
Maximum Cartridge Flow rate, Qcart 7.5 gpm =q * (7.5 ft2/cartridge)
Mass load per cartridge, Mcart (lbs)54 lbs =lookup mass load per cartridge
Number of Cartridges required, Nmass 32 =ROUNDUP(Mfilter/Mcart,0)
Maximum Treatment Capacity 0.53 =Nmass*(Qcart/449)
SUMMARY
Maximum Treatment Flow Rate, cfs 0.53 Target Pollutant(s):TSS, N & P
Cartridge Flow Rate, gpm 7.5 Media:Phosphosorb
Number of Cartridges 32
Determining Number of
Cartridges for Volume-Based
Design in NC
PARK APARTMENTS
WDF-17000
NUTRIENT LOADING CALCULATIONS

Jordan Nutrient Load Reporting Form. September 12, 2012
Jordan Lake Developer Nutrient Reporting Form
(Note: A separate form is available for Neuse, Tar-Pamlico, and Falls Lake reporting.)

Please complete and submit the following information to the local government permitting your development project to
characterize it and assess the need to purchase nutrient offsets. Contact and rule implementation information can be
found online at http://portal.ncdenr.org/web/wq/ps/nps/nutrientoffsetintro.

PROJECT INFORMATION (for Jordan Lake)
Applicant Name:
Woodfield Investments
Project Name:
Park Apartments
Project Address (if available): Street: Ephesus Church Road City/Town: Chapel Hill County: Orange

Date: (mo/d/yr)
06/20/2019
Project
Location :
Lat: (decimal degrees)
35.933139

Long: (decimal degrees)
-79.021256
Is this Redevelopment? - Yes
- No Development Type (Please check all that apply)
Impervious Cover (%):
(Pre-Construction)
47.64%

Commercial
Industrial
Institutional

Mixed-Use
Duplex Residential

Single Fam. Residential
Multi-Fam. Residential
Impervious Cover (%):
(Post-Construction)
65.30%
JORDAN WATERSHED INFORMATION
Small Watershed ID (6 digits): (See next page or online map.)

New Development Load Requirements (See individual rules
for a full description of nutrient requirements.)
Jordan Subwatershed (Please check one) Loading Rate Targets
Nitrogen (N) & Phosphorus (P) Offsite Thresholds
Haw River 3.8 N lb/ac/yr
1.43 P lb/ac/yr 6 N lbs/ac Residential;
10 N lbs/ac Commercial
(must meet all onsite treatment
requirements)
Upper New Hope 2.2 N lb/ac/yr
0.82 P lb/ac/yr
Lower New Hope 4.4 N lb/ac/yr
0.78 P lb/ac/yr
NUTRIENT OFFSET REQUEST(Must meet the offsite thresholds – see above)
Nitrogen Loading / Offset Needs
(A) (B) (C) (D) (E) (F) (G) (H) (I) (Where Applicable)
Untreated
Loading Rate
(lbs/ac/yr)
Treated
Loading Rate
(lbs/ac/yr)
Loading Rate
Target
(lbs/ac/yr)
Reduction Need
(lbs/ac/yr)
B - C
Project
Size (ac)
Offset
Duration (yrs)
Delivery
Factor (%)
State Buy Down
Amount (lbs)
D * E * F * G
Local Gov’t Buy Down
Amount (lbs)
8.70 6.26 2.20 4.06 13.66 30 97% 1613.87
Phosphorus Loading / Offset Needs
(A) (B) (C) (D) (E) (F) (G) (H) (I) (Where Applicable)
Untreated
Load Rate
(lbs/ac/yr)
Treated
Load Rate
(lbs/ac/yr)
Loading Rate
Target
(lbs/ac/yr)
Reduction Need
(lbs/ac/yr)
B - C
Project
Size (ac)

Offset
Duration (yrs)
Delivery
Factor (%)
State Buy Down
Amount (lbs)
D * E * F * G
Local Gov’t Buy Down
Amount (lbs)
1.31 0.89 0.82 0.07 13.66 30 96% 27.54
Authorizing Local Government Name:
Staff Name:
Staff Email: Phone:

Jordan Nutrient Load Reporting Form. September 12, 2012

Project Information
Project Name:Park Apartments
Submission Date:06/20/2019
Project Area (ft2):595,197 ft2
Disturbed Area (ft2):595,197 ft2
Development Land Use Type:Multi-Family Residential
Development Activity Type:Development - Expansion
Designated Downtown Area?no
Project Location/Address:Elliot Road
County:Orange
Local Jurisdiction:Chapel Hill
Project Latitude Coordinates:35.933139 N
Project Longitude Coordinates:-79.021256 W
Precipitation Station:Chapel Hill
Physiographic Region:Piedmont
Nutrient Management Watershed:Jordan Lake
Subwatershed:Jordan - Upper New Hope
Phosphorus Delivery Zone:Jordan Zone 10
Nitrogen Delivery Zone:Jordan Zone 10
Project Designer and Contact Phone
Number / Email:Kelli Garcia / [e-mail]
Part of Common Development Plan?no
Project Owner Type:Private
Project Description:
Green cells require data for
NUTRIENT TARGETS,
BUYDOWN, & CREDIT/DEBIT
calculations
Yellow cells require data for
PROJECT AREA RUNOFF and
NUTRIENT TREATMENT
calculations
Roof 1.18 0.11 80,221 132,389
Roadway 1.64 0.34 80,801
Parking/Driveway/Sidewalk 1.42 0.18 203,320 175,436
Protected Forest 0.97 0.03 43,635 3,791
Other Pervious/Landscaping 2.48 1.07 268,021 202,780
CUSTOM LAND COVER 1
CUSTOM LAND COVER 2
CUSTOM LAND COVER 3
LAND TAKEN UP BY SCM 1.18 0.11
SIMPLE METHOD Stormwater Runoff Volume Generated, V
Runoff Coefficient, R v V =Pj * Rv * (P/12) * A
Rv = 0.05 + (0.009 *I)where A =drainage area (ft2)
where I =percent impervious (%)Pj =
Average Annual Pollutant Load, L P =
L =
where C =
Pre-Project:Post-Project:
A = 13.6638 ac A =13.6638 ac
P = 47.31 in.P =47.31 in.
V = 1011062 ft3 V =1346643 ft3
I = 48%I = 65%
Rv = 0.48 Rv = 0.64
Pj = 0.9 Pj = 0.9
CTN = 1.40 mg/L CTN = 1.41 mg/L
CTP = 0.20 mg/L CTP = 0.21 mg/L
LTN = 88.53 lb/yr LTN = 118.82 lb/yr
LTP = 12.75 lb/yr LTP = 17.90 lb/yr
Net Change of Land Covers (ft2):132,969
Total Pre-Project Calculated Area (ft2):
Total Post-Project Calculated Area (ft2):
Total Project Area Entered (ft2):595,197
595,197
595,197
LAND COVER AREA CHECK
PROJECT AREA LAND COVERS
TN
EMC
(mg/L)
TP
EMC
(mg/L)
Post-
Project
Area (ft2)
Pre-
Project
Area (ft2)
event mean concentration (mg/L)
Equations Used and Project Area Calculations
fraction of rain events with runoff
average annual rainfall depth (in)
(Pj * Rv * (P/12 )) * (C * A * 2.72)
3. SCM Characteristics
Catchment ID 1 1 1
SCM ID 101 102 103
Type of SCM StormFilter per MDC
Predominant hydrologic soil
group at SCM location D
SCM Description SCM B
Design Storm Size (inches/24hrs)1.00
Percent of Full Size 100%
Hydrologic Value - Percent
Annual Effluent 90%
Hydrologic Value - Percent
Annual Overflow 10%
Hydrologic Value - Percent
Annual ET/Infiltrated 0%
SCM Effluent TP EMC (mg/L)0.03
SCM Effluent TN EMC (mg/L)0.48
SCM Land Cover TP EMC (mg/L)0.11
SCM Land Cover TN EMC (mg/L)1.18
Drains to SCM ID 0
Catchment Routing
(Source Catchment)Catchments Draining to
SCM 101
Catchments Draining to
SCM 102
Catchments Draining to
SCM 103
Catchment 1
Catchment 2
Catchment 3
Catchment 4
Catchment 5
Catchment 6
SCM ID:101 102 103
SCM Drainage Area Land Covers Area Draining Directly to
SCM 101 (ft2)
Area Draining Directly to
SCM 102 (ft2)
Area Draining Directly to
SCM 103 (ft2)
Total Land Use Area
Treated By All SCMs (ft2)
Allowable Total Land Use
Area to be Treated Based
on Post-Project Areas (ft2)
Post-Project Untreated
Land Area (ft2)
Roof 79,222 79,222 132,389 53,167
Roadway 28,548 28,548 80,801 52,253
Parking/Driveway/Sidewalk 89,064 89,064 175,436 86,372
Protected Forest 0 3,791 3,791
Other Pervious/Landscaping 46,828 46,828 202,780 155,952
CUSTOM LAND COVER 1 0 0 0
CUSTOM LAND COVER 2 0 0 0
CUSTOM LAND COVER 3 0 0 0
LAND TAKEN UP BY SCM 0 0 0
TOTAL AREA DRAINING TO SCM
(ft2):
243,662 0 0 243,662 595,197 351,535
CATCHMENT AREA (ft2):243,662
Project Summary
595,197 ft2 13.6638 acres
595,197 ft2 13.6638 acres
96%97%
0.82 2.20
11.20 30.06
12.18 85.50
10.00
6.70 88.76
0.97 55.44
0.94 53.78
Nutrient Export Summary
Pre-Project
Whole Site
Conditions
Post-Project
Whole Site
without SCMs
Post-Project
Whole Site with
SCMs
Post-Project
SCM-Treated
Area
Post-Project
Untreated Area
47.6%65.3%65.3%80.8%54.6%
47.6%65.3%65.3%80.8%54.6%
1,011,062 1,346,643 1,346,643 671,803 674,840
0%33%33%
1.40 1.41 1.02 0.58 1.46
88.53 118.82 85.50 24.13 61.37
6.48 8.70 6.26 4.31 7.60
0%34%-3%
0.20 0.21 0.14 0.05 0.24
12.75 17.90 12.18 2.09 10.09
0.93 1.31 0.89 0.37 1.25
0%40%-4%
Orange Local Jurisdiction:Chapel Hill
Total Phosphorus % Change (relative to pre-D)
Total P Load Reduction Needed (lb/yr):
Nitrogen Loading Rate Target (lb/ac/yr):
Nitrogen Load Target at Site (lb/yr):
Nitrogen Load Leaving Site w/SCMs (lb/yr):
N Offsite Buy-Down Threshold Load (lb/ac/yr):
Total N Load Reduction Needed (lb/yr):
Private
Submission Date:
June 20, 2019
Total Phosphorus Load Leaving Site (lb/yr)
Total Phosphorus Loading Rate (lb/ac/yr)
Percent Built-Upon Area (BUA) (%)
Annual Runoff Volume (ft3)
Annual Runoff % Change (relative to pre-D)
Total Nitrogen EMC (mg/L)
Total Nitrogen Load Leaving Site (lb/yr)
Development Activity Type:
Percent Impervious (for runoff calculation) (%)
Total Phosphorus EMC (mg/L)
Phosphorus Loading Rate Target (lb/ac/yr):
Phosphorus Load Target at Site (lb/yr):
Phosphorus Load Leaving Site w/SCMs (lb/yr):
P Offsite Buy-Down Threshold Load (lb/ac/yr):
Park Apartments
Total Nitrogen Loading Rate (lb/ac/yr)
Total Nitrogen % Change (relative to pre-D)
Project Name:
Project Area (ft2):
Disturbed Area (ft2):
County:
Development Land Use Type:
P Load Treatment Balance at Lake (lb/yr):N Load Treatment Balance at Lake (lb/yr):
Nutrient Management Watershed:
Phosphorus Delivery Zone:
N Load Treatment Balance at Site (lb/yr):
Phosphorus Delivery Factor (%):
P Load Treatment Balance at Site (lb/yr):
Nitrogen Delivery Factor (%):
Owner Type:
Designated Downtown Area?
Subwatershed:
Nitrogen Delivery Zone:
Multi-Family Residential
no
Jordan - Upper New Hope
Jordan Zone 10
Jordan Lake
Jordan Zone 10
Development - Expansion
CLIENT
REVISIONS
PROJECT NO.
FILENAME
CHECKED BY
DRAWN BY
SCALE
DATE 02. 28. 2019
N0.DATE
\\johnrmcadams.com\dfsrt1\Projects\WDF\WDF-17000\Storm\Form District Permit\Current Drawings\WDF17000-PRE.dwg, 5/2/2019 11:15:53 AM, Ballard, CraigThe John R. McAdams Company, Inc.
2905 Meridian Parkway
Durham, NC 27713
phone [phone]
fax [phone]
license number: C-0293
www.mcadamsco.com
PARK APARTMENTSFORM DISTRICT PERMIT1250 EPHESUS CHURCH ROADCHAPEL HILL, NORTH CAROLINA, 27517SHEET
PLAN INFORMATION
WOODFIELD INVESTMENTS
11425 HORSEMAN'S TRAIL
RALEIGH, NC 27613
PHONE: [phone]
FINAL DRAWING - NOT RELEASED FOR CONSTRUCTION
WDF-17000
1 05. 03. 2019 PER CHAPEL HILL AND OWASA COMMENTS
GRAPHIC SCALE
0 25 50 100
1 inch = 50 ft.
WDF17000-PRE
KEG
SCB
1" = 50'
PRE DEVELOPMENT
NUTRIENT MAP
PRE-TN
LEGEND
PROPERTY AREA
TOTAL: 595,197 sf
NUTRIENT BOUNDARY
TOTAL: 595,197 sf
IMPERVIOUS AREA - ROOF
TOTAL: 80,221 sf
IMPERVIOUS AREA - PARKING/DRIVEWAY/SIDEWALK
TOTAL: 203,320 sf
WOODED AREA
TOTAL: 43,635 sf
OPEN AREA
TOTAL: 268,021 sf
E
P
H
E
S
U
S

C
H
U
R
C
H

R
D
FRANC
E
S
S
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GRAPHIC SCALE025501001 inch = 50 ft.WDF17000-POSTJESBMS1" = 50'POST DEVELOPMENTNUTRIENT MAPPOST-TNFRANCES STEPHESUS CHURCH RD.(VARIABLE WIDTH PUBLIC R/W)DESIGNED BY KIMLEY HORNELLIOTT RD(VARIABLE WIDTH PUBLIC R/W)DESIGNED BY KIMLEY HORNCLIENTREVISIONSPROJECT NO.FILENAMECHECKED BYDRAWN BYSCALEDATE02. 28. 2019N0.DATEX:\Projects\WDF\WDF-17000\Storm\Form District Permit\Current Drawings\WDF17000-POST.dwg, 6/20/2019 8:40:59 AM, Saur, Brieana
The John R. McAdams Company, Inc.2905 Meridian ParkwayDurham, NC 27713phone [phone]fax [phone]license number: C-0293www.mcadamsco.comPARK APARTMENTS
FORM DISTRICT PERMIT
1250 EPHESUS CHURCH ROAD
CHAPEL HILL, NORTH CAROLINA, 27517SHEETPLAN INFORMATIONWOODFIELD INVESTMENTS11425 HORSEMAN'S TRAILRALEIGH, NC 27613PHONE: [phone]FINAL DRAWING - NOT RELEASED FOR CONSTRUCTIONWDF-17000105. 03. 2019PER CHAPEL HILL AND OWASA COMMENTS206. 20. 2019PER CHAPEL HILL AND OWASA COMMENTSLEGENDPROPERTY AREATOTAL: 595,197 sfNUTRIENT BOUNDARYTOTAL: 595,197 sfIMPERVIOUS AREA - PARKING/DRIVEWAY/SIDEWALK (TREATED)TOTAL: 89,064 sfWOODED AREA - (BYPASS)TOTAL: 3,791 sfOPEN AREA - (TREATED)TOTAL: 46,828 sfIMPERVIOUS AREA - ROOF (BYPASS)TOTAL: 53,167 sfIMPERVIOUS AREA - PARKING/DRIVEWAY/SIDEWALK (BYPASS)TOTAL: 86,372 sfSUB-BASINS TO TREATMENT SCMSIMPERVIOUS AREA - ROADWAY (BYPASS)TOTAL: 52,253 sfOPEN AREA - (BYPASS)TOTAL: 155,952 sfIMPERVIOUS AREA - ROOF (TREATED)TOTAL: 79,222 sfIMPERVIOUS AREA - ROADWAY (TREATED)TOTAL: 28,548 sf06-20-2019