Low Impact Development

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Low Impact Development Guidance Document

View or download the Sarasota County Low Impact Development Guidance Document.

 

Low Impact Development

Low Impact Development (LID) is a stormwater management approach that uses a suite of hydrologic controls (structural and non-structural) distributed throughout the site and integrated as a treatment train (i.e., in series) to replicate the natural hydrologic functioning of the predevelopment landscape.

Unlike conventional systems, which typically control and treat runoff using a single engineered stormwater pond located at the “bottom of the hill,” LID systems are designed to promote volume attenuation and treatment at or near the source of stormwater runoff via distributed retention, detention, infiltration, treatment, and reuse mechanisms. The fundamental goal of applying LID concepts, design, and practice is to improve the overall effectiveness and efficiency of stormwater management relative to conventional systems, reducing total and peak runoff volumes and improving the quality of waters discharged from the site.
 
A site-specific suite of LID integrated management practices can be applied to most if not all development scenarios in Sarasota County. Regardless of the project context, LID requires consideration of the following core site planning and design objectives:
  1. Preserve or conserve existing site features and assets that facilitate predevelopment hydrologic function.
  2. Minimize generation of runoff from impervious surfaces (i.e., use peak and total volume controls) and contamination (i.e., use load controls) as close to the source as possible.
  3. Promote distributed retention, detention, treatment, and infiltration of runoff.
  4. Capture and reuse stormwater on site.
  5. Minimize site disturbance and compaction of soils through low impact clearing, grading, and construction measures.

The toolbox of LID integrated management practices to facilitate these objectives is extensive, including structural and non-structural designs, and LID projects are most effective when applied in a treatment train, or series of complementary stormwater management tools and techniques.
 
In addition, an LID stormwater management approach is most effective when sites are evaluated for LID compatibility as early as possible in the planning process and site considerations are considered carefully in the design and construction of each LID practice. This manual supports Sarasota County’s goal of applying the LID concept and design where feasible to enhance existing stormwater management measures and reduce the adverse impacts of land development projects on the county’s natural resources.