The Stormwater Blog 

The low impact development (LID) movement seeks to provide solutions that reduce impervious area and restore predevelopment hydrology. It is understood that small storms (with a frequency less than 6 months) are responsible for most annual urban runoff and groundwater recharge, and LID facilities are designed to reduce the volume and peak rate of the urban runoff from these small storm events using small-scale, engineered on-site hydrologic controls featuring natural components.

Stormwater policy is put in place to control non-point source pollution and is usually tied to the National Pollution Discharge Elimination System Permit (NPDES). Implementation tends to take a while – not for a lack of desire to protect our water resources, but because it is often challenging to integrate stormwater policy through the existing local political structure. Planning and zoning codes, public work drainage infrastructure requirements, and public health and safety standards (to name a few) can all potentially be affected by changes to stormwater policy.

Having worked in the field of stormwater management for almost 20 years, and seeing the conceptual and technological development of stormwater management and BMPs, it is clear we have had successes and failures. We need to learn from both, especially with USEPA’s national rulemaking activities to establish a program to reduce stormwater discharges and to make other regulatory improvements to strengthen its existing stormwater program .

The intent of LEED Sustainable Sites Credit 6.2 is “to limit disruption and pollution of natural water flows by managing stormwater runoff,” and the requirements necessary for meeting this intent are clearly spelled out: capture 90% of the average annual rainfall and treat it by removing 80% of the total suspended solids (TSS). While the rating system does not define TSS it does recommend reliance on field monitoring data that is compliant with the Technology Acceptance Reciprocity Partnership (TARP) protocol or the Technology Acceptance Protocol-Ecology (TAPE) when screening stormwater best management practices (BMPs). Seemingly straightforward, but...