HomeMy WebLinkAbout04.1 StormwaterManagement-SWPPP e
STORMWATER MANAGEMENT
DESIGN MEMO
Project name Lake Hawkeye Conceptual Design
Project no. 1940113922
Client TeraWulf
Memo no. 1
Version 0
To TeraWulf
From Ramboll
Prepared by Carley Wood
Checked by Andrew Stering
Approved by Brian Whittaker
Date March 25, 2026
This memorandum is a summary with attachments, and is organized as
follows:
• Introduction
• Methodology
• Soils Ramboll
• Pre-developed Conditions 101 First Street4th Floor
• Post-developed Conditions Utica, NY 13501
• Stormwater Quality USA
• Runoff Reduction Volume
• Erosion and Sediment Controls T 315-956-6950
• Downstream Drainage Area Analysis F 315-790-5434
• Conclusion https://ramboll.com
• Attachments (Bound Separately)
• Attachment 1 - USGS Map
• Attachment 2 - Soil Survey Information
• Attachment 3 - Pre-developed and Post-Developed Drainage Area Maps
(See note 1 below)
• Attachment 4 - Pre-developed Conditions Stormwater Calculations (See
note 1 below)
• Attachment 5 - Post-developed Conditions Stormwater Management and
Water Quality Calculations
1. These attachments are still in development and will be produced and included
upon final design and SWPPP development prior to the submission for the
construction general permit.
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1 Introduction
The Developer, TeraWulf, has authorized Ramboll to design the storm sewer and stormwater
management facilities within the data center site. The purpose of this memorandum is to summarize
pre- and post-developed conditions including the stormwater quantity and quality measures to be
provided.
The TeraWulf data center is located in the Town of Lansing, NY, south of Genoa, NY, east of Interlaken,
NY, and west of Groton, NY. The site location is shown on the USGS Map (Attachment 1).
This site discharges directly to Cayuga Lake (a fifth order or higher water body) which according to
pages 4-6 and 4-7 of the stormwater design manual waives the requirement of Channel protection
volume (CPv), Overbank Flood Control Criteria (Qp), and Extreme Flood Control (Qf). As such, the site
will be designed focusing on water quality volume (WQv) and runoff reduction volume (RRv) with the
ultimate goal of providing RRv >_ WQv eliminating the need for additional Water Quality Treatment
practices on site.
2 Methodology
The Autodesk Storm and Sanitary Analysis (ASSA) Modeling Software which utilizes the United States
Department of Agriculture (USDA) Soil Conservation Service (SCS) Technical Release No. 55 (SCS TR-
55) and TR-20 (SCS TR-20) methodologies were utilized to determine pre- and post-development
stormwater runoff rates and to design the stormwater management facilities. The storm sewer system
will be designed to convey a 10-year storm and flood routes will be designed to convey a 100-year
frequency in accordance with the Town of Lansing standards.
Rainfall data was obtained from NRCC and NRCS joint collaborative website
(http://precip.eas.cornell.edu) Extreme Precipitation in New York & New England, An Interactive Web
Tool for Extreme Precipitation Analysis. The following is a summary of the 24-hour extreme precipitation
estimates for the site.
2-1. Summary of 24-hour Extreme Precipitation Estimates (inches)
2-year 5-year 10-year 25-year 50-year 100-year
Site 2.30 2.84 3.34 4.12 4.84 5.68
Source: Values were taken from http://precip.eas.cornell.edu website.
3 Soils
A USDA Web Soil Survey of the data center site in Tompkins County, New York identifies numerous soil
types on the site. The predominant soil types are Hudson-Cayuga silt loams, 2 to 6 percent slopes
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(HuB) and Hudson-Cayuga silt loams, 6 to 12 percent slopes, eroded (HuC3). See Attachment 2 for the
Soil Survey Information on the soils located on the project site.
4 Pre-developed Conditions
The 540-acre site generally consists of woods and brush with a retired power plant facility on site. The
site has been divided into two drainage areas under pre-developed conditions. The two drainage areas
are located at the west end of the site. The northernmost drainage area is a tributary discharging into
Cayuga Lake. The southern drainage area is located near the retired power plant facility and discharges
through an existing culvert into Cayuga Lake through two 54"diameter concrete pipes. The drainage
areas will be included as Attachment 3 (Pre-developed and Drainage Area Maps) upon completion and
development of the full SWPPP prior to the construction general permit application.
The following is a summary of the pre-developed peak stormwater runoff rates for various design
storms. The information and models used to estimate these rates can be found in Attachment 4 - Pre-
Developed Conditions Stormwater Calculations.
5 Post-developed Conditions
It is proposed to develop the site with a data center complex, replacing a portion of the northwestern
wooded areas of the site. As the project results in the disturbance of more than 1-acre of land a
NYSDEC SPDES Permit for Stormwater Discharges from Construction Activities must be obtained for the
project. The SPDES Permit requires stormwater quality measures be provided.
Under post-developed conditions the site will consist of twenty-eight (28) drainage areas that will be
directed to stormwater management areas (SMA's). The SMA's will provide the required stormwater
runoff reduction volume. The area that was tributary to the pre-developed Drainage Area upstream of
the site will be bypassed with swales of adequate size to be designed at a later date.
The SMA's are designed to provide mitigation for stormwater quality in accordance with NYSDEC
requirements and the stormwater design manual. Per the NYSDEC General Permit for Stormwater
Discharges from Construction Activity, Permit No. GP-0-25-001 (effective January 29, 2025 with an
expiration date of January 28, 2030) (CGP), the Channel Protection Volume (CPv), Overbank Flood
Control Criteria (Qp), and Extreme Flood Control Criteria (Qf) requirements do not apply as this site
discharges directly into a fifth order or larger water body. The points of discharge are required to be
adequately protected against scour and erosion.
The runoff reduction practices are all sized to store and infiltrate the WQv storm with overflow to each
practice being discharged through an on-site stormwater network. The discharge point for the proposed
stormwater network will be protected from erosion and discharge to the existing dual-54" culverts on
site that direct flow to Cayuga lake.
The post-developed condition calculations are provided in Attachment 5 (Post-Developed Conditions
Stormwater Management and Water Quality Calculations) and the post-developed drainage area map is
still in development but will be included as attachment 4 (Post-developed Drainage Area Maps) upon
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final SWPPP development and permit application. Conceptual level design drawings are included under
separate cover. A table of the post construction drainage areas (DA)'s is included below:
5-1. Summary of Post Construction Drainage Areas'
SMP Area
Impervious SMP Area Impervious
DA area DA area
Description (acres) Description (acres)
(acres) (acres)
Stormwater
1 1.22 1.22 15 Tree Trench (RR-3) 0.09 Yes
planters (RR-7)
Stormwater
2 1.22 1.22 16 Tree Trench (RR-3) 0.17 0.17
Planters (RR-7)
Stormwater 3 Planters ater ter 1.22 1.22 17 Tree Trench (RR-3) 0.16 0.16
Stormwater
4 1.22 1.22 18 Tree Trench (RR-3) 0.16 0.16
Planters (RR-7)
5 Stormwater 1.22 1.22 19 Tree Trench (RR-3) 0.08 0.08
Planters (RR-7)
Stormwater 6 Planters ater ter 1.22 1.22 20 Tree Trench (RR-3) 0.07 0.07
7 Stormwater 0.15 0.15 21 Tree Trench (RR-3) 0.17 0.17
Planters (RR-7)
8 Stormwater 0.15 0.15 22 Stormwater 4.71 4.71
Planters (RR-7) Planters (RR-7)
9 Stormwater 1.63 0.66 23 Stormwater 4.71 4.71
Planters (RR-7) Planters (RR-7)
10 Tree Trench 17.97 14.56 24 Stormwater 1.11 1.11
(RR-3) Planters (RR-7)
11 Tree Trench 0.24 0.24 25 Stormwater 1.11 1.11
(RR-3) Planters (RR-7)
12 Tree Trench 0.41 0.41 26 Tree Trench (RR-3) 7.89 3.44
(RR-3)
13 Tree Trench 0.34 0.34 27 Tree Trench (RR-3) 0.91 0.91
(RR-3)
Tree Trench
14 0.47 0.47 28 Tree Trench (RR-3) 1.91 1.91
(RR-3)
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6 Stormwater Quality
Stormwater quality measures in accordance with the requirements of the NYS Stormwater Management
Design Manual are provided by the SMPs. The following is a summary table of the WQv required for
each drainage area going towards a post-construction stormwater practice. No additional stormwater
treatment was required since the RRv was equal to the WQv required (see section 7). Calculations of
the stormwater quality volume for each SMA are provided in Attachment 5 (Post-developed Conditions
Stormwater Management and Water Quality Calculations).
6-1. Summary of WQv Required'
Post-construction Drainage WQv Required Post-construction WQv Required
Area (DA) (cubic ft) Drainage Area (DA) (cubic ft)
1 4,207 15 310
2 4,207 16 579
3 4,207 17 545
4 4,207 18 545
5 4,207 19 272
6 4,207 20 238
7 509 21 579
8 509 22 16,243
9 2,452 23 16,243
10 50,829 24 3,828
11 828 25 3,828
12 1,414 26 12,671
13 1,172 27 3,138
14 1,621 28 6,587
7 Runoff Reduction Volume
The proposed Stormwater Planters (RR-7) and tree trenches (RR-3) will provide RRv for the site. The
minimum required RRv was not calculated since RRv provided was >_ WQv. RRv practices and volumes
are shown below.
1 Note-several practices were consolidated on the attached stormwater calculations due to limitations in the excel sheet provided by NYSDEC which only
allows a maximum of 10 individual locations of each practice.For example,drainage areas 1&2 were consolidated into just 1 in the attached printouts.
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7-1. Summary of Required and Provided Runoff Reduction Volumes (RRv)
Runoff RRv Is Runoff RRv Is
Reduction Provided RRv Reduction Required RRv
DA Volume Practice (cubic aDA Volume (cubic >_
ft)Z WQv? Practice ft) WQv?
1 Stormwater planters 4,207 Yes 15 Tree Trench (RR-3) 310 Yes
(RR-7)
2 Stormwater Planters 4,207 Yes 16 Tree Trench (RR-3) 579 Yes
(RR-7)
3 Stormwater Planters 4,207 Yes 17 Tree Trench (RR-3) 545 Yes
(RR-7)
4 Stormwater Planters 4,207 Yes 18 Tree Trench (RR-3) 545 Yes
(RR-7)
5 Stormwater Planters 4,207 Yes 19 Tree Trench (RR-3) 272 Yes
(RR-7)
6 Stormwater Planters 4,207 Yes 20 Tree Trench (RR-3) 238 Yes
(RR-7)
7 Stormwater Planters 509 Yes 21 Tree Trench (RR-3) 579 Yes
(RR-7)
8 Stormwater Planters 509 Yes 22 Stormwater 16,243 Yes
(RR-7) Planters (RR-7)
9 Stormwater Planters 2,452 Yes 23 Stormwater 16,243 Yes
(RR-7) Planters (RR-7)
10 Tree Trench (RR-3) 50,829 Yes 24 Stormwater 3,828 Yes
Planters (RR-7)
11 Tree Trench (RR-3) 828 Yes 25 Stormwater 3,828 Yes
Planters (RR-7)
12 Tree Trench (RR-3) 1,414 Yes 26 Tree Trench (RR-3) 12,671 Yes
13 Tree Trench (RR-3) 1,172 Yes 27 Tree Trench (RR-3) 3,138 Yes
14 Tree Trench (RR-3) 1,621 Yes 28 Tree Trench (RR-3) 6,587 Yes
Of note - several of the stormwater planters are shown in the conceptual level plans as a consolidated
unit. The design intent of these is to divide the planters up into discrete areas receiving rooftop flow
through a spreader box so that the planters are able to treat and infiltrate the stormwater reaching
z Part of the calculation of RRv provided by each practice sets the maximum value to the WQv of the drainage area.All practices are sized greater than the
requirement to treat the WQv and would provide more RRv than shown if the maximum wasn't set.
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them. This meets design intent of the stormwater design manual and each practice where the drainage
area exceeds 15,000 should be seen as several discrete planters in a shared area.
8 Erosion and Sediment Controls
Contractors shall install erosion and sediment control measures to eliminate transport of sediment
offsite. Erosion and sediment control measures will be discussed in Section 5.1 of the SWPPP and
detailed in the Construction Drawings upon detailed design and permit applications. These measures will
be implemented by the Contractor and shall adhere to the specifications in the Contract Documents.
Unless specific approval has been obtained from the NYSDEC the Contractors shall only disturb up to 5
acres at one time, which may require phasing of the construction to stabilize completed areas prior to
disturbing additional areas. The construction sequence outlining the specific measures and sequence for
provision of the measures is provided in the Contract Drawings, which are bound separately from this
SWPPP. Development of a detention basin or other temporary erosion and sediment controls may be
required and are not shown on the conceptual level design plans.
9 Conclusion
Runoff reduction practices are distributed across the proposed development site to work as a
decentralized stormwater management system. The areas of the runoff reduction practices were set
during conceptual design to be greater than what would be required for the water quality volume of the
upstream area so that the entire water quality volume is reduced as part of the project. Since the
Runoff Reduction Volume is equal to the Water Quality Volume, no additional quality treatment practices
are required. Additionally, the stormwater runoff will be directed into a water body of order 5 or higher,
so there are no stormwater quantity management requirements for the site. The stormwater system
and drainage facilities were designed in accordance with the NYS DEC Stormwater Management Design
Manual, most recent edition. In total, the Water Quality Volume for the site was approximately 3.45
acre-feet, all of which is reduced using a combination of Tree Trenches (RR-3) & Stormwater Planters
(RR-7).
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ATTACHMENT 1
USGS Map
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ROAD CLASSIFICATION
IJW YORK
Produced by the United States Geological Survey Expressway Local Connector
North American Datum of 1983(NAD83) * SCALE 1:24 000 Secondary Hwy Local Road
World Geodetic System of 1984(WG584). Projection and MN Ramp 4WD
1 000-meter grid:UNIVERSAL TRANSVERSE MERCATOR,ZONE 18T G4 1 0.5 0 KILOMETERS 1 2
Data is provided by The National Map(TNM),is the best available at the time of map 11*32" QUADRANGLE LOCATION .Interstate Route C3 US Route O State Route
generation,and includes data content from supporting themes of Elevation, 205 MILS 1000 500 0 METERS 1000 2000
Hydrography,Geographic Names,Boundaries,Transportation,Structures,Land Cover, 1°6' 1 0.5 0 1
and Orthoimagery.Refer to associated Federal Geographic Data Committee(FGDC) 20 MILS
MILES
Metadata for additional source data information.
1000 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 Sheldrake Genoa
This map is not a legal document.Boundaries may be generalized for this map scale. UTM GRID AND 2026 MAGNETIC NORTH FEET
Private lands within government reservations may not be shown.Obtain permission DECLINATION AT CENTER OF SHEET
before entering private lands.Temporal changes may have occurred since these data
were collected and some data may no longer represent actual surface conditions. U.S.National Grid CONTOUR INTERVAL 10 FEET
100,000-m Square ID NORTH AMERICAN VERTICAL DATUM OF 1988
Learn About The National Map:https://nationalmap.gov CONTOUR SMOOTHNESS=Medium Trum nsburg Ludl w0lle 7.5-MINUTE TOPO, NY
UN
2026
Grid Zone Designation
18T
ADJOINING QUADRANGLES
ATTACHMENT 2
Soil Survey Information
Soil Map—Tompkins County, New York 3:
M
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3652M 365500 365800 366100 366400 366700 367000 367300 367600 367900
42o 36 48"N 42'36 48"N
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42o 35'47"N - 42o 35'47"N
365200 365500 36.5800 366100 366400 366700 367000 367300 367600 367900
3 3
Map Scale:1:13,200 i printed on A landscape(11"x 8.5")sheet.
Meters
NN 0 150 300 600 900
Feet
k0 500 1000 2000 3000
Map projection:Web Mercator Comer coordinates:WGS84 Edge tics:UTM Zone 18N WGS84
USDA Natural Resources Web Soil Survey 3/2/2026
Conservation Service National Cooperative Soil Survey Page 1 of 3
Soil Map—Tompkins County, New York
MAP LEGEND MAP INFORMATION
Area of Interest(AOI) Spoil Area The soil surveys that comprise your AOI were mapped at
Area of Interest(AOI) 1:20,000.
Stony Spot
Soils Please rely on the bar scale on each map sheet for map
Soil Map Unit Polygons Very Stony Spot measurements.
Soil Map Unit Lines Wet Spot Source of Map: Natural Resources Conservation Service
� •
Other Web Soil Survey URL:
O Soil Map Unit Points Coordinate System: Web Mercator(EPSG:3857)
«� Special Line Features
Special Point Features Maps from the Web Soil Survey are based on the Web Mercator
V Blowout Water Features projection,which preserves direction and shape but distorts
Streams and Canals distance and area.A projection that preserves area,such as the
Borrow Pit Albers equal-area conic projection,should be used if more
Transportation x Clay Spot accurate calculations of distance or area are required.
a-�-r Rails
Closed Depression This product is generated from the USDA-NRCS certified data as
..i Interstate Highways of the version date(s)listed below.
Gravel Pit US Routes
Soil Survey Area: Tompkins County, New York
Gravelly Spot Major Roads Survey Area Data: Version 21,Sep 2,2025
r Landfill Local Roads Soil map units are labeled(as space allows)for map scales
Lava Flow 1:50,000 or larger.
Background
Marsh or swamp Aerial Photography Date(s)aerial images were photographed: Apr 1,2020—Oct 1,
® 2020
Mine or Quarry
The orthophoto or other base map on which the soil lines were
Miscellaneous Water compiled and digitized probably differs from the background
imagery displayed on these maps.As a result,some minor
Perennial Water shifting of map unit boundaries may be evident.
Rock Outcrop
_ Saline Spot
Sandy Spot
.. Severely Eroded Spot
Sinkhole
Slide or Slip
oa Sodic Spot
USDA Natural Resources Web Soil Survey 3/2/2026
Conservation Service National Cooperative Soil Survey Page 2 of 3
Soil Map-Tompkins County,New York
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
Ab Alluvial land 3.3 0.4%
BtF Bath,Valois,and Lansing soils, 36.0 4.1%
35 to 60 percent slopes
CfB Conesus gravelly silt loam,3 to 23.6 2.7%
8 percent slopes
Gn Genesee silt loam 0.9 0.1%
HdC Howard gravelly loam,5 to 15 55.4 6.3%
percent simple slopes
HdCK Howard gravelly loam,5 to 15 10.0 1.1%
percent complex slopes
HpE Howard and Palmyra soils,25 1.7 0.2%
to 35 percent slopes
HsB Hudson silty clay loam,2 to 6 33.1 3.8%
percent slopes
HuB Hudson-Cayuga silt loams,2 154.3 17.6%
to 6 percent slopes
HuB3 Hudson-Cayuga silt loams,2 3.8 0.4%
to 6 percent slopes,eroded
HuC3 Hudson-Cayuga silt loams,6 139.9 16.0%
to 12 percent slopes,eroded
HuD Hudson-Cayuga silt loams, 12 28.3 3.2%
to 20 percent slopes
IcB Ilion silty clay loam,2 to 6 5.1 0.6%
percent slopes
LbB Lansing gravelly silt loam,3 to 37.6 4.3%1
8 percent slopes
LbC Lansing gravelly silt loam,8 to 9.8 1.1%
15 percent slopes
LmB Lima silt loam,3 to 8 percent 4.4 0.5%
slopes
Mc Made land 45.7 5.2%
OaA Ovid silt loam,0 to 6 percent 104.6 11.9%
slopes
RkB Rhinebeck silt loam,2 to 6 10.3 1.2%
percent slopes
Ro Rock outcrop 45.8 5.2%
W Water 121.7 13.9%
Totals for Area of Interest 875.2 100.0%
USDA Natural Resources Web Soil Survey 3/2/2026
Conservation Service National Cooperative Soil Survey Page 3 of 3
ATTACHMENT 5
Post-developed Conditions Stormwater Management
and Water Quality Calculations
Step 2 - Calculate Water Quality Volume
Is this project subject to Section 4.3 of the NYS Design Manual for Enhanced Phosphorus
Removal? No
What is the nature of this construction project? New Construction
Design Point:1 1 Enter 90% Rainfall Event as P
P=J 1.00 linches
Calculate Required WQv
Contributing Percent
Drainage Area Impervious Area WQv SMP
Number (ACr es) (Acres) Impeor ious Rv (cf) Description
1 2.44 2.44 100 0.95 8,414 Stormwater
Planter
2
3 2.44 2.44 100 0.95 8,414 Stormwater
Planter
4
5 2.44 2.44 100 0.95 8,414 Stormwater
Planter
6
7 0.30 0.30 100 0.95 1,017 Stormwater
Planter
8
9 1.63 0.66 40 0.41 2,452 Stormwater
Planter
10 17.97 14.56 81 0.78 50,829 Tree Trench
11 0.24 0.24 100 0.95 828 Tree Trench
12 0.41 0.41 100 0.95 1,414 Tree Trench
13 0.34 0.34 100 0.95 1,172 Tree Trench
14 0.47 0.47 100 0.95 1,621 Tree Trench
15 0.09 0.09 100 0.95 310 Tree Trench
16 0.80 0.80 100 0.95 2,759 Tree Trench
17
18
19
20
21
22 11.64 11.64 100 0.95 40,141 Stormwater
Planter
23
24
25
26 7.89 3.44 44 0.44 12,671 Tree Trench
27 0.91 0.91 100 0.95 3,138 Tree Trench
28 1.91 1.91 100 0.95 6,587 Tree Trench
29
30
Total 51.92 43.09 83 0.80 150181 Required WQv
Steps 3 and 5 - Apply RR Techniques and Standard SMPs
Runoff Rec!Ma , lume and Treated Volumes
Total Total 7
Runoff Reduction Techiques/Standard Co tributing Contributing Reduced WQv Treated
SMPs Area Impervious (RRv)
Area
(acres) (acres) (cf) (cf)
Conservation of Natural Areas RR-1 0.00 0
Sheet Flow to Riparian Buffer/Filter Strip RR-2 0.00 0.00 0
Tree Planting/Tree Pit/Tree Trench RR-3 31.03 23.17 81,329
Disconnection of Rooftop Runoff RR-4 0.00 0
2, Vegetated Swale RR-5 0.00 0.00 0
U
Rain Garden RR-6 0.00 0.00 0
H Stormwater Planter RR-7 20.89 19.92 68,852
Rainwater Harvesting Systems RR-8 0.00 0.00 0
Porous Pavement RR-9 0.00 0.00 0
Green Roof(Extensive & Intensive) RR-10 0.00 0.00 0
Stream Daylighting RR-11
_ Infiltration Trench 1-1 0.00 0.00 0 0
3 Infiltration Basin 1-2 0.00 0.00 0 0
0- 'M Dry Well 1-3 0.00 0.00 0 0
U) 0.
M Underground Infiltration System 1-4 0.00 0.00 0 0
� v Infiltration Bioretention F-4 0.00 0.00 0 0
_ Filtration Bioretention F-5 0.00 0.00 0 0
Bioslope F-6 0.00 0.00 0 0
CO
Dry swale 0-1 0.00 0.00 0 0
Micropool Extended Detention P-1 0.00 0.00 0
Wet Pond P-2 0.00 0.00 0
Wet Extended Detention P-3 0.00 0.00 0
Multiple Pond System P-4 0.00 0.00 0
a Shallow Wetland W-1 0.00 0.00 0
v�i Extended Detention Shallow Wetland W-2 0.00 0.00 0
M
Pond/Wetland System W-3 0.00 0.00 0
c
Pocket Wetland W-4 0.00 0.00 0
Gravel Wetland W-5 0.00 0.00 0
Surface Sand Filter F-1 0.00 0.00 0
Underground Sand Filter F-2 0.00 0.00 0
Perimeter Sand Filter F-3 0.00 0.00 0
Wet Swale 0-2 0.00 0.00 0
y Flow Based Alternative Practice - 0.00 0.00 0
Q Volume Based Alternative Practice -
Totals by RR Technique 51.92 43.09 150,181
Totals by Standard SMP w/RRV 0.00 0.00 0 0
Totals by Standard SMP 0.00 0.00 0
Totals by Alternative SMP 0.00 0.00 0
Totals ( RR Techniques + all SMPs) * 51.92 43.09 150,181 0
Tree Trench (RR-3)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number
Area Area Impervious Rv (cf) ( ) Description
(Acres) (Acres) % in
10 17.97 14.56 81 0.78 50,829 1.00 Tree Trench
Design Criteria
Is the contributing area a designated hotspot? No
Enter the slope of the contributing area (%) 10.00
Enter underlying soil infiltration rate (based on 0.50
geotechnical testing, refer to Appendix D)
Enter depth to seasonal high water table (ft) 40
Enter depth to bedrock (ft) 42
Enter surface layer depth (inches) 3
Enter filter media width (ft) 19
Enter drainage layer depth (inches) 24
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 50,829 cf
Enter Filter Bed Depth df 3.00 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.50 ft
Enter Filter Time tf 2 days
Required Filter Bed Surface Area Af 21784 sf
Provided Filter Bed Surface Area Af 24584 sf
Calculate Runoff Reduction
RRv Provided 50,829 cf
Tree Trench (RR-3)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number Area Area Impervious Rv (cf) (in) Description
(Acres) (Acres) %
11 0.24 0.24 100 0.95 828 1.00 Tree Trench
Design Criteria
Is the contributing area a designated hotspot? No
Enter the slope of the contributing area (%) 3.00
Enter underlying soil infiltration rate (based on 0.50
geotechnical testing, refer to Appendix D)
Enter depth to seasonal high water table (ft) 15
Enter depth to bedrock (ft) 15
Enter surface layer depth (inches) 3
Enter filter media width (ft) 10
Enter drainage layer depth (inches) 24
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 828 cf
Enter Filter Bed Depth df 3 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Enter Filter Time tf 2 days
Required Filter Bed Surface Area Af 355 sf
Provided Filter Bed Surface Area Af 400 sf
Calculate Runoff Reduction
RRv Provided 1 828 jcf
Tree Trench (RR-3)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number Area Area Impervious Rv (cf) (in) Description
(Acres) (Acres) %
12 1 0.41 1 0.41 1 100 1 0.95 1 1,414 1 1.00 1 Tree Trench
Design Criteria
Is the contributing area a designated hotspot? No
Enter the slope of the contributing area (%) 10
Enter underlying soil infiltration rate (based on
geotechnical testing, refer to Appendix D) 0.5
Enter depth to seasonal high water table (ft) 2
Enter depth to bedrock (ft) 2
Enter surface layer depth (inches) 3
Enter filter media width (ft) 10
Enter drainage layer depth (inches) 24
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 1,414 cf
Enter Filter Bed Depth df 3 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Enter Filter Time tf 2 days
Required Filter Bed Surface Area Af 606 sf
Provided Filter Bed Surface Area Af 893 sf
Calculate Runoff Reduction
RRv Provided 1 1,414 jcf
Tree Trench (RR-3)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number Area Area Impervious Rv (cf) (in) Description
(Acres) (Acres) %
13 1 0.34 1 0.34 1 100 1 0.95 1 1,172 1 1.00 1 Tree Trench
Design Criteria
Is the contributing area a designated hotspot? No
Enter the slope of the contributing area (%) 0.5
Enter underlying soil infiltration rate (based on
geotechnical testing, refer to Appendix D) 0.5
Enter depth to seasonal high water table (ft) 2
Enter depth to bedrock (ft) 2
Enter surface layer depth (inches) 3
Enter filter media width (ft) 10
Enter drainage layer depth (inches) 24
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 1,172 cf
Enter Filter Bed Depth df 3 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Enter Filter Time tf 2 days
Required Filter Bed Surface Area Af 502 sf
Provided Filter Bed Surface Area Af 797.9 sf
Calculate Runoff Reduction
RRv Provided 1 1,172 jcf
Tree Trench (RR-3)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number Area Area Impervious Rv (cf) (in) Description
(Acres) (Acres) %
14 0.47 0.47 100 0.95 1,621 1.00 Tree Trench
Design Criteria
Is the contributing area a designated hotspot? No
Enter the slope of the contributing area (%) 10
Enter underlying soil infiltration rate (based on 0.5
Enter depth to seasonal high water table (ft) 2
Enter depth to bedrock (ft) 2
Enter surface layer depth (inches) 3
Enter filter media width (ft) 10
Enter drainage layer depth (inches) 24
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 1,621 cf
Enter Filter Bed Depth df 3 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Enter Filter Time tf 2 days
Required Filter Bed Surface Area Af 695 Isf
Provided Filter Bed Surface Area Af 1 908 Isf
Calculate Runoff Reduction
RRv Provided 1 1,621 lcf
Tree Trench (RR-3)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number Area Area Impervious Rv (cf) (in) Description
(Acres) (Acres) %
15 0.09 0.09 100 0.95 310 11.64 Tree Trench
Design Criteria
Is the contributing area a designated hotspot? No
Enter the slope of the contributing area (%) 0.5
Enter underlying soil infiltration rate (based on 0.5
Enter depth to seasonal high water table (ft) 2
Enter depth to bedrock (ft) 2
Enter surface layer depth (inches) 3
Enter filter media width (ft) 10
Enter drainage layer depth (inches) 24
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 310 cf
Enter Filter Bed Depth df 3 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Enter Filter Time tf 2 days
Required Filter Bed Surface Area Af 133 sf
Provided Filter Bed Surface Area Af 400 sf
Calculate Runoff Reduction
RRv Provided 1 310 lcf
Tree Trench (RR-3)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number Area Area Impervious Rv (cf) (in) Description
(Acres) (Acres) %
16 0.80 0.80 100 0.95 2,759 0.00 Tree Trench
Design Criteria
Is the contributing area a designated hotspot? No
Enter the slope of the contributing area (%) 10
Enter underlying soil infiltration rate (based on 0.5
Enter depth to seasonal high water table (ft) 2
Enter depth to bedrock (ft) 2
Enter surface layer depth (inches) 3
Enter filter media width (ft) 10
Enter drainage layer depth (inches) 24
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 2,759 cf
Enter Filter Bed Depth df 3 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Enter Filter Time tf 2 days
Required Filter Bed Surface Area Af 1 1182 Isf
Provided Filter Bed Surface Area Af 1 2175 Isf
Calculate Runoff Reduction
RRv Provided 1 2,759 lcf
Tree Trench (RR-3)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number Area Area Impervious Rv (cf) (in) Description
(Acres) (Acres) %
26 1 7.89 1 3.44 1 44 1 0.44 1 12,671 1 0.00 1 Tree Trench
Design Criteria
Is the contributing area a designated hotspot? No
Enter the slope of the contributing area (%) 10
Enter underlying soil infiltration rate (based on 0.5
Enter depth to seasonal high water table (ft) 2
Enter depth to bedrock (ft) 2
Enter surface layer depth (inches) 3
Enter filter media width (ft) 10
Enter drainage layer depth (inches) 24
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 12,671 cf
Enter Filter Bed Depth df 3 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Enter Filter Time tf 2 days
Required Filter Bed Surface Area Af 5430 sf
Provided Filter Bed Surface Area Af 5475 sf
Calculate Runoff Reduction
RRv Provided 1 12,671 jcf
Tree Trench (RR-3)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number Area Area Impervious Rv (cf) (in) Description
(Acres) (Acres) %
27 0.91 0.91 100 0.95 3,138 0.00 Tree Trench
Design Criteria
Is the contributing area a designated hotspot? No
Enter the slope of the contributing area (%) 10
Enter underlying soil infiltration rate (based on 0.5
Enter depth to seasonal high water table (ft) 24
Enter depth to bedrock (ft) 26
Enter surface layer depth (inches) 3
Enter filter media width (ft) 10
Enter drainage layer depth (inches) 24
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 3,138 cf
Enter Filter Bed Depth df 3 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Enter Filter Time tf 2 days
Required Filter Bed Surface Area Af 1 1345 Isf
Provided Filter Bed Surface Area Af 1 1350 Isf
Calculate Runoff Reduction
RRv Provided 1 3,138 lcf
Tree Trench (RR-3)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number Area Area Impervious Rv (cf) (in) Description
(Acres) (Acres) %
28 1.91 1.91 100 0.95 6,587 0.00 Tree Trench
Design Criteria
Is the contributing area a designated hotspot? No
Enter the slope of the contributing area (%) 10
Enter underlying soil infiltration rate (based on 0.5
Enter depth to seasonal high water table (ft) 2
Enter depth to bedrock (ft) 2
Enter surface layer depth (inches) 3
Enter filter media width (ft) 10
Enter drainage layer depth (inches) 24
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 6,587 cf
Enter Filter Bed Depth df 3 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Enter Filter Time tf 2 days
Required Filter Bed Surface Area Af 1 2823 Isf
Provided Filter Bed Surface Area Af 1 2850 Isf
Calculate Runoff Reduction
RRv Provided 1 6,587 lcf
Stormwater Planter (RR-7)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number
Area Area Impervious Rv (cf) ( ) Description
(Acres) (Acres) % in
1 2.44 2.44 100 0.95 8,414 1.00 Stormwater
Planter
Select stormwater planter type Infiltration Stormwater Planter
Design Criteria
Enter underlying soil infiltration rate (based on
geotechnical testing, refer to Appendix D) 0.5
Is the contributing area a designated hotspot? No
Does the contributing area exceed 15,000 sf? Yes Does not meet design criteria as a single unit.Distribute flow into discrete planters
Does contributing area contain parking lot or
roadway runoff? No
Enter depth to seasonal high water table (ft) 13
(4 ft min separation in sole source aquifer)
Enter depth to bedrock (ft) 13
Enter depth of surface layer(inches) 3
Enter drainage layer depth (inches) 6
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 8,414 cf
Enter Depth of Soil Media df 2.5 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Filter Time tf 2 days
Required Filter Area Af 3506 sf
Enter Provided Filter Area Af 5503.89 sf
Recalculated Water Quality Volume (based on WQv calc 13209.336 cf
provided filter area)
Calculate Runoff Reduction
RRv Provided 8,414 cf
Stormwater Planter (RR-7)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number
Area Area Impervious Rv (cf) ( ) Description
(Acres) (Acres) % in
3 2.44 2.44 100 0.95 8,414 1.00 Stormwater
Planter
Select stormwater planter type j1nfilt-rafion Stormwater Planter
Design Criteria
Enter underlying soil infiltration rate (based on
geotechnical testing, refer to Appendix D) 0.5
Is the contributing area a designated hotspot? No
Does the contributing area exceed 15,000 sf? Yes Does not meet design criteria as a single unit.Distribute flow into discrete planters
Does contributing area contain parking lot or
roadway runoff? No
Enter depth to seasonal high water table (ft) 10
(4 ft min separation in sole source aquifer)
Enter depth to bedrock (ft) 12
Enter depth of surface layer (inches) 3
Enter drainage layer depth (inches) 6
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 8,414 cf
Enter Depth of Soil Media df 2.5 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Filter Time tf 2 days
Required Filter Area Af 3506 sf
Enter Provided Filter Area Af 5503.89 sf
Recalculated Water Quality Volume (based on WQv calc 13209.336 cf
provided filter area)
Calculate Runoff Reduction
RRv Provided 8,414 cf
Stormwater Planter (RR-7)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number
Area Area Impervious Rv (cf) ( ) Description
(Acres) (Acres) % in
5 2.44 2.44 100 0.95 8,414 1.00 Stormwater
Planter
Select stormwater planter type j1nfilt-rafion Stormwater Planter
Design Criteria
Enter underlying soil infiltration rate (based on
geotechnical testing, refer to Appendix D) 0.5
Is the contributing area a designated hotspot? No
Does the contributing area exceed 15,000 sf? Yes Does not meet design criteria as a single unit.Distribute flow into discrete planters
Does contributing area contain parking lot or
roadway runoff? No
Enter depth to seasonal high water table (ft) 5
(4 ft min separation in sole source aquifer)
Enter depth to bedrock (ft) 7
Enter depth of surface layer (inches) 3
Enter drainage layer depth (inches) 6
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 8,414 cf
Enter Depth of Soil Media df 2.5 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Filter Time tf 2 days
Required Filter Area Af 3506 sf
Enter Provided Filter Area Af 5503.89 sf
Recalculated Water Quality Volume (based on WQv calc 13209.336 cf
provided filter area)
Calculate Runoff Reduction
RRv Provided 8,414 cf
Stormwater Planter (RR-7)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number
Area Area Impervious Rv (cf) ( ) Description
(Acres) (Acres) % in
7 0.30 0.30 100 0.95 1,017 1.00 Stormwater
Planter
Select stormwater planter type j1nfilt-rafion Stormwater Planter
Design Criteria
Enter underlying soil infiltration rate (based on
geotechnical testing, refer to Appendix D) 0.5
Is the contributing area a designated hotspot? No
Does the contributing area exceed 15,000 sf? No
Does contributing area contain parking lot or
roadway runoff? No
Enter depth to seasonal high water table (ft) 2
(4 ft min separation in sole source aquifer)
Enter depth to bedrock (ft) 3
Enter depth of surface layer (inches) 3
Enter drainage layer depth (inches) 6
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 1,017 cf
Enter Depth of Soil Media df 2.5 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Filter Time tf 2 days
Required Filter Area Af 424 sf
Enter Provided Filter Area Af 707.5 sf
Recalculated Water Quality Volume (based on WQv calc 1698 cf
provided filter area)
Calculate Runoff Reduction
RRv Provided 1,017 cf
Stormwater Planter (RR-7)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number
Area Area Impervious Rv (cf) ( ) Description
(Acres) (Acres) % in
9 1.63 0.66 40 0.41 2,452 1.00 Stormwater
Planter
Select stormwater planter type Infiltration Stormwater Planter
Design Criteria
Enter underlying soil infiltration rate (based on
geotechnical testing, refer to Appendix D) 0.5
Is the contributing area a designated hotspot? No
Does the contributing area exceed 15,000 sf? Yes Does not meet design criteria as a single unit.Distribute flow into discrete planters
Does contributing area contain parking lot or
roadway runoff? No
Enter depth to seasonal high water table (ft) 2
4 ft min separation in sole source aquifer
Enter depth to bedrock (ft) 3
Enter depth of surface layer (inches) 3
Enter drainage layer depth (inches) 6
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 2,452 cf
Enter Depth of Soil Media df 2.5 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Filter Time tf 2 days
Required Filter Area Af 1022 sf
Enter Provided Filter Area Af 3150 sf
Recalculated Water Quality Volume (based on WQv calc 7560 cf
provided filter area)
Calculate Runoff Reduction
RRv Provided 2,452 cf
Stormwater Planter (RR-7)
Design Point: 1
Enter Site Data For Drainage Area to be Treated by Practice
Contributing Impervious Percent
Drainage Area WQv Precipitation
Number Area Area Impervious Rv (cf) (in) Description
(Acres) (Acres) %
22 11.64 11.64 100 0.95 40,141 0.00 Stormwater
Planter
Select stormwater planter type jinf—ilt-ration Stormwater Planter
Design Criteria
Enter underlying soil infiltration rate (based on 0.5
Is the contributing area a designated hotspot? No
Does not meet design criteria as a single unit.
Does the contributing area exceed 15,000 sf? Yes Distribute flow into discrete planters
Does contributing area contain parking lot or No
Enter depth to seasonal high water table (ft) 2
Enter depth to bedrock (ft) 2
Enter depth of surface layer (inches) 3
Enter drainage layer depth (inches) 6
Sizing Criteria
Value Units Notes
Water Quality Volume WQv 40,141 cf
Enter Depth of Soil Media df 2.5 ft
Permeability Flow Rate k 1 ft/day
Enter Average Height of Ponding hf 0.5 ft
Filter Time tf 2 days
Required Filter Area Af 16725 sf
Enter Provided Filter Area Af 17200 sf
Recalculated Water Quality Volume (based on WQv calc 41280 cf
Calculate Runoff Reduction
RRv Provided 40,141 lcf