20150378 Ver 1 _Stormwater Impact Analysis w Caculations _20150420

STORMWATER IMPACT ANALYSIS/
STORMWATER NARRATIVE AND CALCULATIONS
FOR
6 Davis Drive Entrance Amendment
Durham County, North Carolina
Prepared for:
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AL E X A N D RIA®
ARE - NC Region No. 14, LLC
6 Davis Drive, P.O. Box 12137
Research Triangle Park, North Carolina 27709
Date: February 16, 2015
Prepared by:
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PROJECT DESCRIPTION
This project involves the construction of a new entry to the 6 Davis Drive campus in
Research Triangle Park, North Carolina. This project is a part of a long -term
masterplanned campus. An earlier site plan for the additions to the 6 Davis Drive
campus was approved previously under D1400055. It is assumed that the construction
approved on these plans will have been completed by the time construction begins on
the entrance drive.
The proposed entrance site is located on the west side of Davis Drive, approximately
0.25 miles north of the interchange where Davis Drive crosses 1 -40.
SITE DESCRIPTION
The existing site is approximately 56.2 acres of mixed hardwood forest which also
accommodates one building that is currently the corporate home for the Hamner
Institutes and is approximately 115,000 square feet. It is currently served by 194 total
parking spaces.
The site lies within the Burden's Creek sub - watershed of the Cape Fear River Basin and
does not lie within any of Durham County's Water Supply Watersheds. The site lies within
the Upper New Hope subwatershed of the overall Jordan Lake watershed.
Two jurisdictional perennial streams are found on the site. Both streams are unnamed
tributaries to Burden's Creek. One stream (Stream A) flows from north to south along
the western property line of the site. Once it exits the site, Stream A flows under 1 -40.
The other stream (Stream B) flows from northeast to southwest and crosses the
southeastern corner of the site. Stream B flows into the adjacent property to the south
and eventually under 1 -40. The two streams eventually converge approximately 0.25
miles downstream from where stream A crosses 1 -40.
Both streams have a 100 -year flood plain that encroaches onto the site. Beyond the
100 -year flood area, portions of the site are located in Zone "X," a 500 year flood area
(see FEMA FIRM Panel 0748 located in the "MAPS" section of this document.)
A ridgeline running from the northeast property corner towards the southwest generally
divides the drainage for the site. The western side of the side drains towards the existing
perennial stream flowing along the western property line. The eastern side of the site
drains towards the stream flowing across the southeastern portion of the site.
SOILS
According to the Durham County Generalized Soil Survey, the majority of uplands within
the site are classified as White Store sandy loam, ranging from 2% to 25% slopes (WsB,
WsC, WsE). Along the banks of the stream, soils are classified as Cartecay and
Chewacla soils, 0% to 2% slopes, frequently flooded (Cc). The following soil descriptions
are associated with the soils found on the site:
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Ws(X) - White Store sandy loam soils are often found in piedmont uplands, along
rounded divides and steep side slopes. These soils were created from
weathered Triassic Mudstone. Permeability is very slow and the soils are
moderately well drained. Soils have a high shrink /swell potential. The seasonal
high water is generally about 1.5 feet below the surface. These soils are in the
Hydrologic Soil Group (HSG) D in the City of Durham Public Works Reference
Guide for Development.
Cc - Cartecay and Chewacla soils are a mixture of approximately 60% Cartecay
and 30% Chewacla. These soils are often found along floodplains at slopes of Oho
to 2 %. Permeability is moderately rapid and the soils are poorly drained. Soils
have a low shrink /swell potential. The seasonal high water is perched and
generally 1.5 feet below the ground surface in the late winter and early spring.
These soils are in the HSG C.
EXISTING POINTS OF ANALYSIS
The existing site was broken into 8 points of analysis where most of the runoff will cross
the property line. Each point of analysis has a contributing drainage area which was
delineated and broken into areas of impervious, and various levels of vegetated cover.
The results are below:
The pre- and post - development runoff numbers for each of the analysis points is
summarized in the table below:
Point of
Analysis
PRE-
DEV.
1 -YR
DIS.
cfs
POST-
DEV.
1 -YR
DIS.
(cfs)
%
INC.
PRE-
DEV.
2 -YR
DIS.
(cfs)
POST-
DEV.
2 -YR
DIS.
(cfs)
%
INC.
PRE-
DEV.
10 -YR
DIS.
(cfs)
POST -
DEV.
10 -YR
DIS.
(cfs)
INC.
DET.
REQ
(Y /N)
A
3.78
3.78
0
5.57
5.57
0
10.60
10.60
0
N
B
5.95
9.19
54.4
8.56
12.89
50.5
15.78
22.93
45.3
Y
C
4.90
5.04
2.8
6.89
7.08
2.7
12.28
12.58
2.4
N
D
3.33
19.49
485.2
4.91
25.12
411.6
9.33
39.48
323.1
Y
E
18.50
16.94
-8.4
24.60
22.52
-8.5
40.45
37.03
-8.5
N
F
2.35
2.35
0
3.41
3.41
0
6.37
6.37
0
N
G
1.41
1.41
0
1.95
1.95
0
3.42
3.42
0
N
H
21.85
27.08
23.9
30.80
36.67
19.0
55.27
61.96
12.1
Y
The drainage areas contributing to Points of Analysis B, D, and H require measures to
attenuate peak flow.
For drainage area contributing to Point of Analysis B, the approved stormwater
collection system consists of installation of bio- retention facility with a design volume of
6,165 CF. The pre- and post - development runoff associated with this BMP are below:
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Storm Event cfs
Site Condition
1 -year cfs
2 -year cfs
10 -year cfs
100 -year cfs
Pre - Development
5.95
8.56
15.78
27.21
Post - Development
Analysis
Area (ac)
Conc.
Peak Runoff
without Detention
9.19
12.89
22.93
38.52
Post - Development
cfs
cfs
H
16.49
Post - Development
1,76
2.24
3.34
10.13
with Detention
121
1.61
10.08
35.54
For drainage area contributing to Point of Analysis D, the approved stormwater
collection system consists of installation of wet detention facility with a design volume of
13,589 CF. The pre- and post - development runoff associated with this BMP are below:
Storm Event cfs
Site Condition
1 -year (cfs)
2 -year (cfs)
10 -year (cfs)
100 -year (cfs)
Pre - Development
3.33
4.91
9.33
16.46
Post - Development
Analysis
Area (ac)
Conc.
Peak Runoff
Peak Runoff
19.49
25.12
39.48
60.67
without Detention
cfs
cfs
H
16.49
Post - Development
36.67
61.96
100.27
with Detention
121
1.61
10.08
35.54
with Detention
For drainage area contributing to Point of Analysis H, the approved stormwater
collection system consists of installation of two bio- retention facilities - one with a design
volume of 7,603 CF and the other with a design volume of 1,928 CF. The pre- and post -
development runoff associated with these BMPs are below:
Storm Event cfs
Site Condition
1- ear cfs
2-year cfs
10- ear cfs
100- ear cfs
Pre - Development
21.85
30.80
55.27
92.38
Post - Development
Analysis
Area (ac)
Conc.
Peak Runoff
Peak Runoff
27.08
36.67
61.96
100.27
without Detention
cfs
cfs
H
16.49
Post - Development
36.67
61.96
100.27
with Detention
14.75
18.85
36.48
65.80
The only point of analysis that is affected by the Entrance site construction is Point H.
Our analysis assumes the previously approved site plan (D1400055) will have been
constructed by the time construction begins at the Entrance.
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Existing
Time
Pre -Dev.
Pre -Dev.
Pre -Dev.
Point of
Drainage
of
2- Yr /24 -Hr
10- Yr /24 -Hr
100- Yr /24 -Hr
Analysis
Area (ac)
Conc.
Peak Runoff
Peak Runoff
Peak Runoff
min.
cfs
cfs
cfs
H
16.49
19.5
36.67
61.96
100.27
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POST - DEVELOPMENT POINT OF ANALYSIS
The developed site was analyzed at the previously defined 8 points of analysis. The
drainage area for point of analysis H will be affected by the new development.
RESULTS
PRE -DEV.
Time
Post -Dev.
Post -Dev.
Post -Dev.
Point of
New
of
2- Yr /24 -Hr
10- Yr /24 -Hr
100- Yr /24 -Hr
10 -YR
Drai age
DET.
Point of
DIS.
Analysis
Area (ac)
Conc.
Peak Runoff
Peak Runoff
Peak Runoff
Analysis
cfs )
min. )
(cfs)
(cfs)
(cfs
H
16.49
19.5
36.79
62.13
100.53
RESULTS
SUMMARY OF RESULTS
Point of Analysis H
Based on the above results, a measure would not need to be installed in the drainage
basin to attenuate the post - development peak runoff.
JORDAN LAKE STORMWATER NUTRIENT LOADING
Nutrient loading calculations were not performed for the initial phase of the 6 Davis
Drive development approved under D1400055 since it was amendment to an approved
site plan that was approved before the Jordan Lake rules were in effect. For the
entrance drive project, the nutrient offset results are summarized on the Jordan Lake
Developer Nutrient Reporting Form included in the appendix. No new stormwater BMPs
are being proposed for this project. The total required offset payment to be made to
EEP or a private nutrient offset bank is $48.07.
CONCLUSIONS
Based on Durham County's requirements set forth in the Durham County Stormwater
Ordinance, section 14- 153.c, all high density developments with greater than 240
impervious area and located outside the Neuse River Basin are required to control and
treat runoff from the first one inch of rainfall and remove 850 of the total suspended
solids, as well as show no net increase in peak flow leaving the site from pre -
development conditions for the one -year, 24 -hour storm event.
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PRE -DEV.
POST -DEV.
PRE -DEV.
POST -DEV.
2 -YR
2 -YR
10 -YR
10 -YR
DET.
Point of
DIS.
DIS.
%
DIS.
DIS.
%
REQ
Analysis
cfs )
(cfs)
INC.
cfs )
(cfs)
INC.
Y/N
H
36.67
36.79
0.31
61.96
62.13
0.28
N
SUMMARY OF RESULTS
Point of Analysis H
Based on the above results, a measure would not need to be installed in the drainage
basin to attenuate the post - development peak runoff.
JORDAN LAKE STORMWATER NUTRIENT LOADING
Nutrient loading calculations were not performed for the initial phase of the 6 Davis
Drive development approved under D1400055 since it was amendment to an approved
site plan that was approved before the Jordan Lake rules were in effect. For the
entrance drive project, the nutrient offset results are summarized on the Jordan Lake
Developer Nutrient Reporting Form included in the appendix. No new stormwater BMPs
are being proposed for this project. The total required offset payment to be made to
EEP or a private nutrient offset bank is $48.07.
CONCLUSIONS
Based on Durham County's requirements set forth in the Durham County Stormwater
Ordinance, section 14- 153.c, all high density developments with greater than 240
impervious area and located outside the Neuse River Basin are required to control and
treat runoff from the first one inch of rainfall and remove 850 of the total suspended
solids, as well as show no net increase in peak flow leaving the site from pre -
development conditions for the one -year, 24 -hour storm event.
5of6

No new stormwater BMPs are required for this project for peak flow attenuation and no
BMPs are being proposed for nutrient treatment due to the existing site conditions and
the small size of the project site area.
POINT OF ANALYSIS H
Research into the downstream system has shown that an existing 72" CMP culvert exists
on the adjacent site to the south. Because of the proximity Point of Analysis H and the
headwall of the 72" CMP pipe, very little additional runoff is received by Stream B
beyond this project's property line. Therefore, an analysis of the upstream runoff
combined with the onsite runoff should give a very close approximation of the runoff
that would be seen by the 72" CMP. This analysis yields the following results:
METHODOLOGIES AND PROCEDURES
These stormwater analyses were based on the guidelines set forth by the City of
Durham's Public Works "Reference Guide for Development."
All time of concentration calculations were made using the TR -55 Segmented
Approach, which is outlined in chapter 3 of "USDA NRCS Hydrologic Urban Hydrology
for Small Watersheds." See appendix for time of concentration calculations. All runoff
calculations are based on the Time of Concentration for a 2 -year, 24 -hour storm.
Runoff calculations were made using the Rational Equation analysis.
The downstream culvert was analyzed using Bentley CulvertMaster v3.3.
All soils were assumed to have a HSG D for simplicity of the calculation and as is
appropriate based on the majority of the soils found on the site as stated above.
CALCULATIONS
All stormwater calculations were based on the City of Durham Public Works Reference
Guide for Development and the NCDENR Stormwater BMP Manual.
All calculations are included in the appendix.
6of6
On -site Post-
Offsite
Total
Storm Event
Development
Drainage
Drainage to
Runoff (cfs)
Through Site
Point of
cfs
Analysis H
2- year /24 -hour
36.79
65.86
102.65
10- year /24 -hour
62.13
112.49
174.62
METHODOLOGIES AND PROCEDURES
These stormwater analyses were based on the guidelines set forth by the City of
Durham's Public Works "Reference Guide for Development."
All time of concentration calculations were made using the TR -55 Segmented
Approach, which is outlined in chapter 3 of "USDA NRCS Hydrologic Urban Hydrology
for Small Watersheds." See appendix for time of concentration calculations. All runoff
calculations are based on the Time of Concentration for a 2 -year, 24 -hour storm.
Runoff calculations were made using the Rational Equation analysis.
The downstream culvert was analyzed using Bentley CulvertMaster v3.3.
All soils were assumed to have a HSG D for simplicity of the calculation and as is
appropriate based on the majority of the soils found on the site as stated above.
CALCULATIONS
All stormwater calculations were based on the City of Durham Public Works Reference
Guide for Development and the NCDENR Stormwater BMP Manual.
All calculations are included in the appendix.
6of6

MAPS

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JORDAN LAKE NUTRIENT
FORMS AND SUMMARY

Jordan Lake Developer Nutrient Reporting Form
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 httD: / /Dortal.ncdenr.ore/ web /wa /Ds /nns /nutrientoffsetintro.
PROJECT INFORMATION (for Jordan take)
Applicant Name:
Project Name:
Project Address (if available): Street: City /Town: County:
Date: (mo/d/yr) Project Lat: (decimal degrees) Long: (decimal degrees)
Location :
Is this Redevelopment? ❑ - Yes
Development Type (Please check all that apply)
❑ - No
Impervious Cover ( %): ❑ Commercial E] Mixed -Use —
� Single Fam. Residential
(Pre- Construction) ❑ Industrial
❑ Duplex Residential ❑ Multi -Fam. Residential
Impervious Cover ( %): ❑ Institutional
(Post- Construction)
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 Offsite Thresholds
Nitrogen N) & Phosphorus P
2.2 N Ib /ac /yr 6 N Ibs /ac Residential;
❑ Upper New Hope 0.82 P Ib /ac /yr 10 N Ibs /ac Commercial
(must meet all onsite treatment
❑ Lower New Hope 4.4 N Ib /ac /yr requirements)
0.78 P Ib /ac /yr
NUTRIENT OFFSET REQUEST (must meet the offsite thresholds - see above)
Nitrogen Loading / Offset Needs
(A) (B) (C) (D) (t) (F) (G) (H)
Untreated Treated Loading Rate Reduction Need Project Offset Delivery State Buy Down
Loading Rate Loading Rate Target (Ibs /ac /yr) Size (ac) Duration (yrs) Factor ( %) Amount (Ibs)
(Ibs /ac /yr) (Ibs /ac /yr) (Ibs /ac /yr) B- C D* E* F* G
30
Phosphorus Loading / Offset Needs
(A) (B) (C) (D) (B) (F) (G) (H)
Untreated Treated Loading Rate Reduction Need Project Offset Delivery State Buy Down
Load Rate Load Rate Target (Ibs /ac /yr) Size (ac) Duration (yrs) Factor ( %) Amount (Ibs)
(Ibs /ac /yr) (Ibs /ac /yr) (Ibs /ac /yr) B- C D* E* F* G
30
Control of Peak Stormwater Flow (1 year 24 hour design storm)
Calculated Predevelopment Peak Flow Calculated Post Development Peak Flow Flow Control Method
Authorizing Local Government Name:
Staff Name:
Staff Email: Phone:
Jordan Nutrient Load Reporting Form. September 12, 2012

Jordan Lake Nutrient Stratega'
onpoint Source Delivery Factors
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Subwa#e�rehe6d aioe�a a161a i - Upper Hope
I I ubwah !'#1 1 Legend
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� �e � 06id4�4 0114
"ID's ' "M ,. °r -11D 0% 60% "Oro !
jM► 6 i4 6d*, V% 0MID M% W% W*i3490 Q M 660146
+64
4V% 90W M W% 611% Aft M. ffift
ris it9p70 3 lix 44 " ' Doom 1 4„+ 61680 6 + 50
FA M% Ar. Pam 05010 Kft r^ OKW 10 [5s 4% -1410 M 14% a'1% 67% Oi94167' aW% 0%
JO .111% 1^ Wk= Zv% k^ a9% x1% 461M M% �
aft 41% n% 61R asrlm airs R% mom so
1^ U% 040M >r% L% asaw 40% a� �n�a4 bs16 pip �p
1TM M DID= U% 54+5, r^ 73% GtiUl16J' frls 5 p 1 1
1,10 5+ft [%14 X lift Wk 10 03♦ 74% 0M 30, 6^ U% � 6q� �€lRf�
.110 WL *%% _ %1% M% %% v% � 67 tV, Ms% eFc t Aii Hr#kl6t�YM� `� -� "� y y Hope
aw 1W are► n1% 3, �o11 �r . � _ � 5� S�1�Mlla##ill
7P► a+,s bas �dbCiy4 �r► "160. � "%
Jordan Nutrient Load Reporting Form. September 12, 2012

I I A I B I C I D I E I F I G IHIIIJIKI L I M I N I o I P I Q I R I S I T I U I
18
19
Watershed Characteristics
Clear All Values l Return to Instructions I Proceed to BMP Characteristics I
Instructions
1. Select your physiographic /geologic region. (see map on 'instructions' page)
2. Enter the area of the entire development in square feet (ft).
3. Select the location that is most representative of the site's precipitation characteristics. (see map on 'instructions' page)
4. For each applicable land use, enter the total area of that land use that lies within the development under pre - development conditions.
5. For each applicable land use, enter the total area of that land use that lies within the development under post - development conditions, before BMP implementation.
6. Ensure that the sum of pre- and post - development areas entered equal the orginal development area.
7. Continue to "BMP Characteristics" tab.
Additional Guidelines
For non - residential watersheds, indicate acreages of each land use type in Column 1 for both pre- and post - development conditions.
For residential watersheds, complete the required information in Column 2 for both pre- and post - development conditions.
If a given land use is not present in the given watershed, leave the cell blank or enter a zero.
Ensure that land use areas entered for both pre- and post - development conditions match the total development area entered in cell 021.
Residential areas may be entered by average lot size (column, part A), or may be separated into individual land uses (column 2, part B) -- do NOT list out individual land uses within an
area already described by lot size.
Unless runoff flowing onto the development from offsite is routed separately around or through the site, the offsite catchment area draining in must be included in the acreage
values of the appropriate land use(s) and treated.
Physiographic /Geologic Region:
Piedmont
Soil Hydrologic Group
D
Precipitation location:
Raleigh
COLUMN 1 -- NON- RESIDENTIAL LAND USES
41,025
Development Name:
6 Davis Drive Entry Amendment
Model Prepared By:
re- P
Post-
TN EMC
TP EMC
Development
_
% -ac lots
-ac lots
Parking
Roof
1 -ac lots
Open /L
INDUSTRI
2 -ac lots
Parking
1.44
0.39
Multi-family
Roof
Open /L andscaped
2.24
TRANSPO
Custo m Lot Size
PART B
High De nsity (interstate, main)
3.67
0.43
Low De nsity (secondary, feeder)
1.4
0.52
Drive way
0.0
1.44
Rural
Parkin
Sidewal k
1.4
1.16
1,720
1,720
PERVIOUS
Roof
Manag ed pervious
3.06
0.59
Sidew
Unman aged (pasture)
3.61
1.56
Lawn
Mana ged pervious
Fores
Natur
Ripari an buffer*
Forest
JURISDICTI ONAL LANDS*
Natural wetland
Riparia
Open w ater
Open water*
LAND TA
LAND TAK EN UP BY BMPs
1.08
0.15
Development
(rng /L) (mg /L) W) )
CIAL
lot 1.44 0.16 7,633
1.08 0.15
andscaped 2.24 0.44 31,672
AL
lot
1.08 0.15
0.44
RTATI O N
1.14 0.47
1.47 0.25 20,528
-- --
nbuffer -- -- 18,777
-- --
*Jurisdictional land uses are not included in nutrient /flow calculations.
Skip to Development Summary
Total Development Area (ft ):
41,025
Development Name:
6 Davis Drive Entry Amendment
Model Prepared By:
DCR
_
% -ac lots
-ac lots
1 -ac lots
2 -ac lots
Multi-family
Town homes
Custo m Lot Size
PART B
Road
*Jurisdictional land uses are not included in nutrient /flow calculations.
Skip to Development Summary
Total Development Area (ft ):
41,025
Development Name:
6 Davis Drive Entry Amendment
Model Prepared By:
DCR
COLUMN 2 -- RESIDENTIAL LAND USES
Custom Pre- Post -
Lot Size Age TN EMC TP EMC Development Development
(ac) (yrs) (mg /L) (mg /L) (ftZ) (ftZ)
PART A
A -ac lots
_
% -ac lots
-ac lots
1 -ac lots
2 -ac lots
Multi-family
Town homes
Custo m Lot Size
PART B
Road
Drive way
0.0
1.44
0.39
Parkin
Roof
Sidew
Lawn
Mana ged pervious
Fores
Natur
Ripari an buffer*
Open water*
LAND TA
-- -- --
-- -- --
-- -- --
-- -- --
-- -- --
-- -- --
-- -- --
-- --
way 1.4 0.52
--
g lot -- 1.44 0.39
-- 1.08 0.15
alk /Patio 1.4 1.16
--
-- 2.24 0.44
-- 3.06 0.59
t -- 1.47 0.25
al wetland* -- -- --
-- -- --
-- -- --
KEN UP BY BMPs -- 1.08 0.15
LAND USE AREA CHECK
Total Development Area Entered (ft z): 41,025
Total Pre - Development Calculated Area (ft): (ft): 41,025
Total Post - Development Calculated Area (ft): 41,025
LAND USE AREA CHECK
Total Development Area Entered (ft z): 41,025
Total Pre - Development Calculated Area (ft): (ft): 41,025
Total Post - Development Calculated Area (ft): 41,025

3. Development Summary
6 Davis Drive Entry Amendment
Prepared By: DCR
Date: February 21, 2015
WATERSHED SUMMARY Ver2.0
REGION:
Piedmont
TOTAL DEVELOPMENT AREA (ft -):
41,025
Percent Impervious ( %)
15%
15%
0%
Pre - Development Conditions
Post - Development Conditions
Post - Development w/ BMPs
Percent Impervious
7.7%
22.8%
22.8%
( %)
Total Nitrogen Loading (lb /ac/yr)
133%
133%
Annual Runoff Volume
-56%
-561Y
(c.f.)
10,067
39,616
39,616
Total Nitrogen EMC
Grassed Swale
0%
1.21
(mg /L)
1.43
1.55
1.55
Total Nitrogen Loading
Level Spdr, Filter
(lb /ac /yr)
1.76
4.08
4.08
0.15
Permeable
Total Phosphorus EMC
(mg /L)
0.81
0.36
0.36
.0.39
Sand Filter
5%
Total Phosphorus Loading
(lb /ac /yr)
1.00
0.94
0.94
Percent Difference Between:
'Negative percent difference values indicate a decrease in runoff volume, pollutant concentration or pollutant loading. Positive values indicate an increase.
BMP SUMMARY Ver2.0
BMP VOLUME REDUCTIONS /EFFLUENT CONCENTRATIONS
Volume Reduction TN Effluent Concen.
Pre -Dev. &
Post -Dev. without BMPs
Pre - Development &
Post - Development with BMPs
Post -Dev without BMPs &
Post -Dev with BMPs
Percent Impervious ( %)
15%
15%
0%
Annual Runoff Volume (c.f.)
294%
294%
0%
Total Nitrogen EMC (mg/L)
9%
9%
0%
Total Nitrogen Loading (lb /ac/yr)
133%
133%
0%
Total Phosphorus EMC (mg /L)
-56%
-561Y
0%
Total Phosphorus Loading (lb /ac /yr)
-5%
-5%
0%
'Negative percent difference values indicate a decrease in runoff volume, pollutant concentration or pollutant loading. Positive values indicate an increase.
BMP SUMMARY Ver2.0
BMP VOLUME REDUCTIONS /EFFLUENT CONCENTRATIONS
Volume Reduction TN Effluent Concen.
TIP Effluent Concen.
( %) (mg/L)
(mg /L)
Bioretention with
CATCHMENT 6
BMP1
BMP2
IWS
50%
0.95
0.12
Bioretention
BMP2
BMP3
BMP1
BMP2
35%
1.00
0.12
without IWS
--
-
-
Dry Detention Pond
0%
1.20
0.20
Grassed Swale
0%
1.21
0.26
Green Roof
50%
1.08
0.15
Level Spdr, Filter
Strip
40%
1.20
0.15
Permeable
Pavement*
0%
1.44
.0.39
Sand Filter
5%
0.92
0.14
Water Harvesting user defined
1.08
0.15
1.01
0.11
Wet Detention Pond 10%
Wetland I 20%
1.08
0.12
•iftreating commercial parking lot, TP effluent concentration = 0.16 mg /L
LReturn to Instructions
Return to Watershed Characteristics
L Return to BMP Characteristics I
Print Summary
CATCHMENT 1
BMP1 BMP2 BMP3
CATCHMENT 2
CATCHMENT 3
CATCHMENT 4
CATCHMENTS
CATCHMENT 6
BMP1
BMP2
BMP3
BMP1
BMP2
BMP3
BMP1.
BMP2
BMP3
BMP1
BMP2
BMP3
BMPS
BMP2
BMP3
--
-
-
--
Catchment Outflow
Total Phosphorus(lb /ac /yr)
Percent Reduction in Phosphorus Load (%) --
--
--
-
--
--
Total Area Treated
(ac)
-
-
Total Inflow Volume
Percent Volume Reduced
--
--
--
--
-
--
--
-
--
--
--
--
-
-
-
--
--
--
Inflow Nitrogen EMC
(mg/L)
--
-
--
Total Inflow Nitrogen
(lb /ac /yr)
--
--
--
-
-
-
--
-
-
--
-
--
-
-
-
-
-
-
Inflow Phosphorus EMC
(mg/L)
-
Total Inflow Phosphorus
(lb /ac /yr)
BMP Outflow
Nitrogen (Ibs /ac /yr)
BMP Outflow
Phosphorus (Ibs /ac /yr)
Catchment Outflow Nitrogen EMC (mg /L) --
Catchment Outflow
Total Nitrogen (lb /ac /yr)
--
-
-
-
--
Percent Reduction in Nitrogen Load
--
Catchment Outflow Phosphorus EMC
(mg /L)
--
--
--
-
-
--
Catchment Outflow
Total Phosphorus(lb /ac /yr)
Percent Reduction in Phosphorus Load (%) --
--
--
-
--
--