Low Impact Development

Low Impact Development (LID) is a total site design approach that conserves and uses existing natural site features and systems integrated with distributed best management practices (BMP) stormwater management controls to mimic and recreate the natural water balance. By mimicking nature, BMPs are able to capture, treat, and infiltrate stormwater. LID site design typically disconnects impervious area flow paths as a broad example of a BMP, which also slows and infiltrates water. LID can be applied on various scales, 1) on site, 2) within a project, or 3) throughout a watershed. LID endeavors to mitigate the adverse impacts that development has on the hydrologic cycle and stormwater runoff by 1) decreasing peak flow rates, 2) reducing volume of runoff, 3) increasing the length of the runoff flow path, 4) increasing localized infiltration 5) reducing flooding frequency, and 6) filtering runoff and improving water quality to receiving waters.

LID's potential advantages incude flood hazard mitigation, water conservation and water quality enhancements. LID can be applied on various scales: on site, within a project, or throughout a watershed. Depending on the scale, HELM has the expertise to develop customized LID alternatives that includes features such as Bioretention Cells (rain gardens), Cisterns or Rain Barrels, Green Roots, Permeable Pavers and Bioswales. We also have the capability to model LID infrastructure within two-dimensional Hydrologic and Hydraulic Models to evaluate the hydraulic performance of LID measures.