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What is Low Impact Development?
What is the role of local government in stormwater management?
Question ~ What is Low Impact Development and how has it been used in the Nashua Region?
Answer ~Development has a major impact on our water resources by replacing natural ground cover with manmade, impervious surfaces. Low Impact Development (LID) is an innovative stormwater management approach that minimizes this impact. LID techniques focus on a specific site and can be applied to new as well as existing developments. These techniques are used to mimic a site’s pre-development hydrology by infiltrating, filtering, storing, evaporating, and detaining runoff close to its source. LID preserves the hydrologic cycle, protects drinking water quality & quantity, benefits fish & wildlife, reduces flooding & property damage, and saves communities money.
Question ~ Can Low Impact Development techniques be used in cold weather climates, such as NH? Have they been tried in the Nashua region?
Answer ~ Absolutely! There are several on-the-ground studies begin conducted in NH to test low impact development techniques throughout the year. Use the links below to view studies from the UNH Stormwater Center and the World Water Congress.
"LID demonstrates superior cold climate performance..."
"LID less prone to seasonal performance variation..."
"Barriers to implementing porous asphalt pavement..."
"LID & bioretention areas in cold climates"Pennichuck Square on Rt. 101A in Merrimack provides a good example of LID techniques in action. Design elements at the site include raingardens, biofilter/bio-retention areas, leaching catch basins, and permeable pavers/porous asphalt. These features help to achieve project goals of natural water quality treatment, on-site infiltration, groundwater recharge, decreased onsite flooding, and reduced stormwater runoff.
Question ~ What is the role of local government in stormwater management?
Answer ~ As part of the National Pollutant Discharge and Elimination System Permit, the Phase II stormwater rule requires operators of municipal separate storm sewer systems (MS4s) in urbanized areas to develop and implement a stormwater management program that addresses six minimum control measures. Operators are generally local municipal governments (cities and towns) and the six minimum control measures include:
1. Public Education – Informing individuals about ways to reduce stormwater pollution in their own neighborhoods and activities.
2. Public Involvement – Involving the public in the development, implementation, and review of the stormwater management program.
3. Illicit Discharge Detection & Elimination – Identifying and eliminating illicit discharges to storm sewer systems.
4. Construction Practices – Requiring construction site operators to address stormwater runoff from active construction sites.
5. Post-construction Activities - Requiring developers, homeowners associations, and property owners to address stormwater runoff after construction activities have ended.
6. Pollution Prevention/Good Housekeeping – Acting as a good example and community steward by addressing stormwater runoff at municipal facilities.
In essence, local governments are responsible for making continual progress on each of these six minimum controls in order to be in compliance with their NPDES permit. These responsibilities may include the development of ordinances, voluntary programs, outreach, and Best Management Practices to prevent pollutants from entering stormwater and ending up in public water bodies. The Environmental Protection Agency has created an extensive menu of Best Management Practices, organized by the six minimum control measures, to help local governments fulfill the requirements of the Phase II program.
Page updated 3/18/08
