Building Resilient Communities: With Low Impact Development (LID): - - PowerPoint PPT Presentation

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Building Resilient Communities: With Low Impact Development (LID): - - PowerPoint PPT Presentation

Dec 10, 2022 525 likes •969 views

Building Resilient Communities: With Low Impact Development (LID): Addressing Climate Change, SWMI and MS4 Stormwater Program Scott Horsley Horsley Witten Group, Inc. Sandwich Boston Providence

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Building Resilient Communities: With Low Impact Development (LID):

Addressing Climate Change, SWMI and MS4 Stormwater Program

Scott Horsley Horsley Witten Group, Inc.

Sandwich Boston Providence Newburyport

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Hydrologic Budget

Precipitation Recharge

Stream

Evapotranspiration Aquifer Runoff

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Septic System Road w/ Catchbasin Pumping Well Precipitation Recharge Aquifer Evapotranspiration

Hydrologic Budget

Stream

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100-Year Design Storms (inches)

Springfield Worcester Boston TP40 Design Storm (1930 – 1960) 6.5 6.5 6.6 Cornell Design Storm (1936 - 2008) 8.8 8.8 8.8 Hydrology Handbook for Conservation Commissions: Appendix F. Rainfall Data for Massachusetts from Rainfall Frequency Atlas of the United States (TP-40). Users of this Handbook should note that current MA DEP written guidance (see DEP Waterlines newsletter -- Fall 2000) requires the use of TP-40 Rainfall Data for calculations under the Wetlands Protection Regulations and the Stormwater Management Policy. More stringent design storms may be used under a local bylaw

  • r ordinance.
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Source: University of New Hampshire

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No building present on lot, 2005 photo

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FEMA 100-year flood, depth > 1 foot, at time building constructed FEMA 100-year flood, depth < 1 foot, at time building constructed Building constructed between 2005 and 2008, in location not designated as FEMA floodplain

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Building constructed between 2005 and 2008, now in regulated floodplain after 2010 FEMA re-study 100-year flood, depth >1 foot, from 2010 FEMA study Prior 100-year flood, depth > 1 foot

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Same building, March 2010 flood (approximately 40-year flood)

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The process begins with determining how many lots could be developed under conventional zoning; this is the base yield of the property. From that point, the plan development process follows four basic steps:

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Identify Conservation Value Areas on the site such as wetlands, significant trees or tracts of forest, habitat, cultural resources or buffer zones. Remove these from the “developable area”. 1.

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Place houses in the remaining area in a way that would maximize residents enjoyment of these areas by providing access to open space and preserving views. 2.

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Align roads and trails on the site to provide pedestrian and vehicle access. 3.

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  • 4. Draw lot lines around the homes.
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Key Stormwater Regulations

Federal Clean Water Act, National Pollutant Discharge Elimination System (NPDES):

  • EPA 2003 MS4 Permits
  • EPA General Stormwater Permit (MA) (expected 2013??)
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Key Stormwater Regulations

Federal Clean Water Act, National Pollutant Discharge Elimination System (NPDES):

  • EPA 2003 MS4 Permits
  • EPA General Stormwater Permit (MA) (expected 2013??)

Massachusetts Initiatives:

  • MA Stormwater Standards (jurisdiction under Wetlands

Protection Regulations)

  • MA Water Management Act (Sustainable Water Management

Initiative, SWMI)

  • MA Climate Change Adaptation Report/Regulatory Changes
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Key Stormwater Regulations

Federal Clean Water Act, National Pollutant Discharge Elimination System (NPDES):

  • EPA 2003 MS4 Permits
  • EPA General Stormwater Permit (MA) (expected 2013??)

Massachusetts Initiatives:

  • MA Stormwater Standards (jurisdiction under Wetlands Protection

Regulations)

  • MA Water Management Act (Sustainable Water Management

Initiative, SWMI)

  • MA Climate Change Adaptation Report/Regulatory Changes

Local Ordinance/Bylaw/Regulations (required MS4)

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LID Stormwater Management Techniques

  • Rain Barrels and Cisterns / Water Re-use
  • Stormwater Planters, Tree Planting
  • Permeable Paving
  • Open Channels
  • Bioretention
  • Stormwater Wetlands
  • Green Rooftop Systems
  • Vegetative Buffers
  • Infiltration
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Permeable Pavement

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Rain Barrels and Cisterns

Runoff Reduction & Water Conservation

  • Downspouts directed to

tanks or barrels

  • 50 –10,000 gallons
  • Excess diverted to

drywell or rain garden

  • Landscaping, car

washing, other non- potable uses

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Dry Well Infiltration of Roof Runoff Disconnection of Rooftop Runoff to Vegetated Swale

Source: CWP Source: Horsley Witten Group

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Permeable Pavement

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Vegetated Swales

Conveyance, Treatment, Infiltration

  • Roadside swales (“country

drainage”) for lower density and small-scale projects

  • For small parking lots
  • Mild side slopes and flat

longitudinal slopes

  • Provides area for snow

storage & snowmelt treatment

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Source: Larry Gavin

Bioretention Applications

  • Parking lot islands
  • Median strips
  • Residential lots
  • Office parks

Source: LID Center

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Rain Garden

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Green Roofs

  • Stormwater Runoff

absorption/collection

  • Reduced flooding of and

damage to urban streets

  • Interior heating and

cooling benefits of 10 degrees or more

  • Air purification
  • Recreational amenity
  • Improved aesthetics
  • Extended roof life,

estimated at 40 years

World Trade Center, Boston

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Stormwater Planters

  • Vegetative uptake of

stormwater pollutants

  • Pretreatment for

suspended solids before they reach water- treatment facilities

  • Aesthetically pleasing
  • Reduction of peak

discharge rate

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Pet Waste Management

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THANK YOU! QUESTIONS?