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Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook...
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Transcript of Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook...
![Page 1: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/1.jpg)
Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed
Bob Hartzel, CLM, CPESCSenior Water Resources Scientist
![Page 2: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/2.jpg)
Project funded through:
Provide planning to aid 5 subwatershed towns in promoting LID as part of master planning, project permitting and development of bylaws.
Organization for the Assabet River
Project Overview / Goals
![Page 3: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/3.jpg)
Project Overview / Goals
Develop model to evaluate the suitability and priority of developable parcels in the Nashoba Brook subwatershed for LID stormwater techniques.
Estimate the benefits and costs of LID stormwater management compared to “conventional” stormwater management.
Vine Brook
Nashoba Brook
![Page 4: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/4.jpg)
Low Impact Development (LID)
An ecosystem-based approach to land development and stormwater management.
Goal: Mimic pre-development site hydrology
![Page 5: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/5.jpg)
![Page 6: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/6.jpg)
![Page 7: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/7.jpg)
Conventional Development
Centralized Pipe Centralized Pipe and Pond Controland Pond Control
![Page 8: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/8.jpg)
LID Development
Disconnected Disconnected Decentralized Decentralized DistributedDistributed
Conservation Conservation Minimization Minimization Soil Amendments Soil Amendments Open Drainage Open Drainage Infiltration BMPsInfiltration BMPsVegetative BMPs Vegetative BMPs Rain Barrels Rain Barrels Pollution PreventionPollution Prevention
Multiple SystemsMultiple Systems
![Page 9: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/9.jpg)
Residential LID Site
![Page 10: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/10.jpg)
LID Stormwater Controls
Rain Garden Treatment Train Approach
Raingarden Cell
Storm Drain System
Raingarden Cell
Flow Path
Grass SwaleGrass Filter
Strip
![Page 11: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/11.jpg)
Low Impact Development Stormwater Controls
Bioretention Raingardens/barrels
Porous surfaces Bioretention
![Page 12: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/12.jpg)
RaingardensA bowl-shaped garden designed to
capture and absorb stormwater.
![Page 13: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/13.jpg)
Bioretention Cell
Similar to raingarden, more highly engineered:
• underdrain/riser pipe
• gravel bed
• engineered soils
![Page 14: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/14.jpg)
Street Edge Alternatives (SEA)
Functional Landscape
Reduced Impervious Area
98% Stormwater volume reduction for 2-year storm
![Page 15: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/15.jpg)
“SEA” Street: Maximized space for filtration, recharge and landscape elements
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![Page 17: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/17.jpg)
![Page 18: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/18.jpg)
Watershed Communities
Town % of watershed
Acton 43%
Westford 35%
Littleton 14%
Carlisle 5%
Concord 3%
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Subwatershed Delineation
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A. “Developable Parcel” Inventory / Map (Not Retrofits)
Unimproved lots > minimum lot size requirement
Municipally owned property that is for sale.
Parcels protected though open space preservation, deed restrictions, etc. = Not Developable
Any portion of a parcel within wetlands = Not Developable
Task 1: Evaluate Parcels Most Suitable for LID
Inventory developed with 5 town planning departments
![Page 21: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/21.jpg)
Developable Parcels Map
198 Parcels
11% of land in watershed
Summary Statistics:
• Size Range: 0.3 – 150 acres
• 50% of land comprised by largest 8% of parcels
• 178 residential parcels
• 12 commercial parcels
• 8 industrial parcels
![Page 22: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/22.jpg)
Task 1: Evaluate Parcels Most Suitable for LID
B. Develop Model to Rank Site Suitability / Priority
S = Soils
D = Distance to Receiving Water
B = Shallow Bedrock
Imp = Impervious Cover Analysis
PWS = Lands Critical to Public Water Supply Quality and Quantity
LID Priority Ranking = 2 (S) + 1 (D) + 1 (Imp) - 1 (PWS) – 1 (B)
![Page 23: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/23.jpg)
“…with proper design and maintenance, LID stormwater techniques can be used successfully at many sites with less than ideal initial conditions.”
Soil Amendments
Underdrains
Steep Slope Designs (Terraces, etc.)
“Not Enough Space”
![Page 24: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/24.jpg)
A newly planted bioretention cell installed in the Dudley Pond watershed (Wayland, MA).
![Page 25: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/25.jpg)
Lake Shirley Bioretention Cell
![Page 26: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/26.jpg)
Lake Shirley Bioretention Cell
Lake Shirley Bioretention Cell Lesson: Small is beautiful!
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Terraced bio-infiltration system (Plymouth, MA)
Lesson:
Sloped areas can be put to work!
![Page 28: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/28.jpg)
Soils
A: Sand, loamy sand or sandy loam soils. High infiltration rates!
B: Silt loam or loam. Moderate infiltration when fully wetted.
C: Sandy clay loam. Poor infiltration when thoroughly wetted.
D: Clay loam, silty clay loam, sandy clay, silty clay or clay. Highest runoff potential, very low infiltration when fully wetted.
Hydrologic Soil Groups
![Page 29: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/29.jpg)
Shallow Bedrock
![Page 30: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/30.jpg)
Impervious Cover Assessment
Total Subwatershed Imperviousness = 12.1%
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Impervious Cover Assessment
Total Subwatershed Imperviousness = 12.1%
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Range = 5.9% - 20.2%
Impervious Cover Assessment
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Public Water Supply Protection
Public Water Supply Wells
Interim Wellhead Protection Areas
Zone 2 Wellhead Protection Areas
Water quantity
Drinking water quality concerns
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Parcel Ranking
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Parcel Ranking
![Page 36: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/36.jpg)
Parcel Ranking…Wetlands
![Page 37: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/37.jpg)
Next Steps: Evaluate the Relative Benefits of LID Techniques
A. Create “Standardized” Development Scenarios LID Conventional Development Cluster / Open Space Development (Residential parcels only)
B. Compare LID vs. Traditional Stormwater Mgt. Water Quality / Quantity Benefits Cost
![Page 38: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/38.jpg)
Parcel Statistics: Choosing a “Representative” Parcel
Median (50th Percentile) Values: Size: 0.9 Acres % IMP: 8.4%
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Examples: “Representative” Residential Parcels
Size: ~0.9 acres Imperviousness: ~8%
![Page 40: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/40.jpg)
Examples: “Representative” Commercial/Industrial Parcels
Size: ~1.3 acres Imperviousness: ~30%
![Page 41: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/41.jpg)
PRECIPITATION
STORAGE
INFILTRATION
RUNOFF
EVAPORATION
SWMM(VOLUME)
EVENT MEAN CONCENTRATION
(QUALITY)
LOAD = RUNOFF VOLUME X EMC
Quantifying LID Benefits: Infiltration and Load Reduction
![Page 42: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/42.jpg)
Modeling Hydrologic Budget: EPA’s SWMM
INPUTS
Precipitation: 57 years of Boston rainfall data
Evaporation: data obtained from MassGIS
Subwatersheds based on surface types: roofs, pavement, lawn, wooded, etc.
Infiltration BMPs: drywells, bioinfiltration
OUTPUTS
Runoff totals from subwatersheds
Precipitation/Runoff statistics
![Page 43: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/43.jpg)
Single Family Lot vs. Residential Subdivision
Parcels with 1-4 buildable lots = “Single Family Lots” (138 parcels, 285 ac.)
Parcels with 5+ buildable lots = “Residential Subdivisions” (40 parcels, 920 ac.)
![Page 44: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/44.jpg)
Conceptual Single Family Lot: Conventional Development
Runoff: 8.9 in/yr Infiltration: 28.1 in/yr TSS: 213 lb/ac/yr TP: 0.72 lb/ac/yr
![Page 45: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/45.jpg)
Conceptual Single Family Lot: Low Impact Development
Runoff: 1.9 in/yr Infiltration: 35.2 in/yr TSS: 68 lb/ac/yr TP: 0.27 lb/ac/yr
Runoff: -7.0 in/yr
Infiltration: +7.1 in/yr
TSS: -145 lb/ac/yr (-68%)
TP: -0.44 lb/ac/yr (-63%)
![Page 46: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/46.jpg)
Conceptual Residential Subdivision: Conventional Development
Runoff: 11.8 in/yr Infiltration: 25.2 in/yr TSS: 330 lb/ac/yr TP: 0.92 lb/ac/yr
![Page 47: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/47.jpg)
Conceptual Residential Subdivision: Low Impact Development
Runoff: 0.7 in/yr Infiltration: 36.5 in/yr TSS: 38.4 lb/ac/yr TP: 0.06 lb/ac/yr
Runoff: -11.1 in/yr
Infiltration: +11.3 in/yr
TSS: -292 lb/ac/yr (-88%)
TP: -0.86 lb/ac/yr (-93%)
![Page 48: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/48.jpg)
Conceptual Commercial/Industrial: Conventional Development
Runoff: 16.3 in/yr Infiltration: 20.8 in/yr TSS: 415 lb/ac/yr TP: 1.73 lb/ac/yr
![Page 49: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/49.jpg)
Conceptual Residential Subdivision: Low Impact Development
Runoff: 1.1 in/yr Infiltration: 36.5 in/yr TSS: 24 lb/ac/yr TP: 0.07 lb/ac/yr
Runoff: -15.2 in/yr
Infiltration: +15.7 in/yr
TSS: -391 lb/ac/yr (-94%)
TP: -1.66 lb/ac/yr (-96%)
![Page 50: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/50.jpg)
LID Benefits: Infiltration
The added infiltration from LID being applied to developable parcels may be as high as:
… for the population of Acton, Littleton, and Westford (~51,500 people)
22 gal/person/day
0 5 10 15 20
Single Family Lot
Residential Subdivision
Commercial/Industrial
gal/person/day
Added Infiltration from LID
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2 extra toilet flushes (1.6 gal each) per person per day…
… for the population of Acton, Littleton, and Westford (~51,500 people)
1 5-minute shower (10 gal) per person per day…
1 dishwasher load (8 gal) per person per day…
22 gal/person/day = approximately…
LID Benefits: Infiltration
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LID Benefits: TSS
… entering Nashoba Brook
The reduction in weight of TSS from LID being applied to developable parcels may be as high as:
190 tons/year
0 50 100 150
Single Family Lot
Residential Subdivision
Commercial/Industrial
tons/yr
Reduction in TSS from LID
![Page 53: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/53.jpg)
LID Benefits: TSS
140 cubic yards of sand/sediment… entering Nashoba Brook each year
190 tons = approximately…
![Page 54: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/54.jpg)
LID Benefits: TP
… entering Nashoba Brook
The reduction in weight of TP from LID being applied to developable parcels may be as high as:
1190 lbs/year
0 400 800
Single Family Lot
Residential Subdivision
Commercial/Industrial
lbs/yr
Reduction in TP from LID
![Page 55: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/55.jpg)
1190 lbs/year of TP = approximately…
….growing per year in Nashoba Brook (and tributary ponds)*assuming 1 lb P : 1026 lb wet Phytoplankton, density Phytoplankton ~ density H20
14,760 cu. ft.
of algae
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COST: LID vs. Conventional Stormwater
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Thank you for your time!
![Page 58: Modeling the Benefits of LID Stormwater Techniques for Developable Parcels in the Nashoba Brook Subwatershed Bob Hartzel, CLM, CPESC Senior Water Resources.](https://reader036.fdocuments.us/reader036/viewer/2022062309/56649cd55503460f9499ca58/html5/thumbnails/58.jpg)
Conventional Design Low Impact Design
Units Unit Cost Qty. Total Qty. Total
LANDSCAPING
Item:
Tree Removal 1 ac $9,150 0.8 $7,320 0.3 $2,745
Clearing/Grubbing 1 ac $7,500 0.9 $6,750 0.38 $2,850
Grass Seed/Sod 1 sy $6 3900 $23,400 1328 $7,968
Native Trees/Shrubs 1,2 ea $30 0 $0 5 $150
Soil Amendment 2 cy $51 0 $0 12 $627
Raingarden/Bioretention 2,3 sf $11 0 $0 770 $8,470
INFRASTRUCTURE/CONVEYANCE/STORAGE
Item:
Standard Asphalt Driveway 2 sy $10 94 $940 0 $0
Porous Pavement Driveway 2,3 sy $108 0 $0 94 $10,152
Drywell - (including inst.) 2 ea $1,500 0 $0 1 $1,500
TOTAL $38,410 $34,462
-10.3%
Notes: Construction/Material costs only. Does not include maintenance or property values.
1. From PA DOT construction cost spreadsheet (ftp://ftp.dot.state.pa.us/public/Bureaus/design/Pub287/Pub%20287.pdf)
2. Geosyntec cost estimate data, past projects
3. "Evaluation of LID Best Management Practices (BMPs) Opportunities," Charles River Watershed Association
Single Family Home
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Residential Subdivision Conventional Design Low Impact Design Units Unit Cost Qty. Total Qty. TotalLANDSCAPING Item:
Tree Removal 1 ac $9,150 0.8 $7,320 3.6 $32,940
Clearing/Grubbing 1 ac $7,500 0.9 $6,750 4.6 $34,500
Grass Seed/Sod 1 sy $6 46800 $280,800 15936 $95,616
Native Trees/Shrubs (for bioretention areas) 1,2 ea $30 0 $0 200 $6,000
Soil Amendment 2 cy $51 0 $0 148 $7,525
Raingarden/Bioretention 2,3 sf $11 0 $0 19100 $210,100 INFRASTRUCTURE/CONVEYANCE/STORAGE Item:
Standard Asphalt Driveway 2 sy $10 1130 $11,300 0 $0
Standard Asphalt Roadway 2 sy $20 4670 $93,400 3090 $61,800
Porous Pavement Driveway 2,3 sy $108 0 $0 1130 $122,040
Drywell - (including inst.) 2 ea $1,500 0 $0 12 $18,000
Catch Basins 1,2 ea $3,000 7 $21,000 0 $0
CPP Storm Drain Pipe 1 lf $75 1710 $128,250 180 $13,500
Vegetated Swale 2 sf $2 0 $0 1840 $3,680
Detention Pond 2,4 cy $15 2450 $36,750 0 $0
Outlet Structure 2 ea $1,500 1 $1,500 0 $0 TOTAL $587,070 $605,701 3.2%
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Commercial / Industrial Conventional Design Low Impact Design
UnitsUnit Cost Qty. Total Qty. Total
LANDSCAPING Item: Tree Removal 1 ac $9,150 1.1 $10,065 0.8 $7,320 Clearing/Grubbing 1 ac $7,500 1.1 $8,250 0.8 $6,000 Grass Seed/Sod 1 sy $6 3390 $20,340 1940 $11,640 Native Trees/Shrubs (for bioretention areas) 1,2 ea $30 0 $0 24 $720 Soil Amendment 2 cy $51 0 $0 18 $916 Raingarden/Bioretention 2,3 sf $11 0 $0 1800 $19,800 INFRASTRUCTURE/CONVEYANCE/STORAGE Item: Standard Asphalt Parking 2 sy $10 1475 $14,750 1100 $11,000 Porous Pavement Parking 2,3 sy $108 0 $0 370 $39,960 Drywell - (including inst.) 2 ea $1,500 0 $0 1 $1,500 Catch Basins 1,2 ea $3,000 3 $9,000 0 $0 CPP Storm Drain Pipe 1 lf $75 325 $24,375 0 $0 Vegetated Swale 2 sf $2 0 $0 470 $940 Detention Pond 2,4 cy $15 340 $5,100 0 $0 Outlet Structure 2 ea $1,500 1 $1,500 0 $0 TOTAL $93,380 $99,796 6.9%
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Costs: Literature Review Comparison