Urban Impaired Stream Standard

1
Urban Impaired Stream Standard

• Project cannot cause or contribute to an
  impairment of a waterbody
• Standard BMPs dont get 100 removal
• Impaired Stream Standard provides a means for
  mitigation.

2
Urban Impaired Stream Standard

• Projects with 3 acres of impervious area
  located within the direct watershed of an urban
  impaired stream must meet the standard
• Chapter 502 identifies 32 urban impaired streams

3
Urban Impaired Stream Watershed Maps
http//www.maine.gov/dep/blwq/docstand/stormwater/
stream_map_1.htm
S. Portland West S. Portland East
Portland
4
Urban Impaired Stream Standard

• Projects must either
• Pay a compensation fee
• or
• Treat, reduce or eliminate an off-site or on-site
  pre-development stormwater source

5
Urban Impaired Stream Standard

• Exceptions
• Disturbed areas neither impervious or landscaped
• Redevelopment of equivalent use

6
Urban Impaired Stream Standard
Fees for partial acreage are prorated
7
Urban Impaired Stream Standard

• Example
• 3 acres parking, 1 acre roof, 2 acres lawn
• Required compensation fee calcualtion
• Fee (3 X 5000) (1 X 2000) (2 X 1000)
• Fee 19,000
• Reqired credit calcualtion
• Credits (3 X 0.5) (1 X 0.2) (2 X 0.1)
• Credits 1.9

8
Urban Impaired Stream Standard
9
Urban Impaired Stream Standard

• Example 3acre