Page 409 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

Low-Impact Development and Stormwater Issues 369

Erosion Prevention Practices Sediment Control Practices
Surface roughening Sediment basin
Mulching Multipurpose basin
Erosion control blankets (ECBs) Sediment dam (trap)
Turf reinforcement mats (TRMs) Silt fence
Dust control Ditch check
• Rock
• Sediment tube
Polyacrylamide (PAM) Stabilized construction entrance
Stabilization Inlet protection
• Temporary • Filter fabric
• Riprap for channel • Block and gravel
• Final • Hardware fabric and stone
• Block and gravel curb
• Prefabricated
Outlet protection Rock sediment dikes

TABLE 10.1.7 Typical Erosion Prevention and Sediment Control Practices Taught
in ESC Certification Classes (CEPSCI, 2005)

When the construction is nearing completion, additional measures are permanently
installed on the site so that erosion does not occur after construction. These range from
vegetative measures to using riprap or constructed erosion prevention devices.

LID
The main concepts of low-impact development (LID) are to minimize the impacts of
development, mainly the stormwater-related impacts. This is done usually by mimicking
the natural hydrologic cycle at the site or project as much as possible and mimicking the
natural hydrologic runoff cycle. So how does one implement the design goal of
mimicking the former site hydrology with LID features? There are essentially four main
parameters of site hydrology which can be used to do this:
• Storage
• Infiltration and the recharge of groundwater
• Evaporation and evapotranspiration
• Detention

And there are a series of many concepts that can help do this. The main ones as listed in
the Prince George’s County (1999) LID manual and as amended are as follows:

• Reduce added imperviousness.
• Conserve natural resources.
• Maintain natural drainage courses.
• Reduce use of pipes, use open-channel sections.