Ineffective stormwater management is a serious problem nationwide. Conventional strategies based around “gray” collection and conveyance systems—networks of gutters, storm drains, and sewers—have not solved persistent stormwater problems. Instead they have shifted, and in many cases exacerbated, the impacts of stormwater runoff, trading urban flooding for pollution and physical alteration of nearby rivers, streams, lakes, and estuaries. Communities searching for cost-effective solutions to their stormwater woes are increasingly recognizing the benefits of a more holistic management approach that employs a locally tailored mix of stormwater control measures, including green stormwater infrastructure (GSI). Well-implemented GSI keeps stormwater local. It works by infiltrating or evaporating precipitation where it falls or capturing it for later use. The goal is to minimize the quantity and maximize the quality of urban runoff that flows to local waters. GSI is a critical tool for solving stormwater management challenges. However, it is evolving technology with inconsistent performance and uncertain costs. Addressing knowledge gaps through enhanced learning from local implementation efforts would speed cost-effective deployment. The EPA and state water quality authorities are already beginning to require GSI for Clean Water Act compliance in some stormwater permits and combined sewer overflow (CSO) consent decrees. A natural extension would be to add or expand associated monitoring and reporting requirements.
This report outlines key actions regulators can take to drive GSI information collection and sharing to accelerate cost-effective GSI deployment.
Action 1: Incentivize and highlight the importance of voluntary GSI monitoring and data contributions to the International Stormwater Best Management Practices Database (ISBMPD).
Action 2: Identify quantitative and qualitative GSI monitoring priorities at the national, regional, and watershed level.
Action 3: Adopt standardized GSI monitoring and reporting protocols and guidance.
Action 4: Attach specific monitoring and reporting requirements to GSI required by National Pollutant Discharge Elimination System (NPDES) permits and consent decrees. Some requirements would be broadly applicable (e.g., context, cost, maintenance, and qualitative performance data and lessons learned). However, a limited subset of GSI installations (consistent with the priorities identified in Action 2) would also require quantitative performance monitoring.
Action 5: Capture required GSI monitoring data in the ISBMPD. This could involve requiring individual implementers to submit data directly to the ISBMPD, collecting information first in state or regional databases that regularly feed accumulated data into the ISBMPD, or coordinating data submission with implementation of the NPDES Electronic Reporting Rule by redesigning the NPDES Integrated Compliance Information System to facilitate carryover of monitoring data to the ISBMPD.
Action 6: Feed water-quality related GSI monitoring data into the National Stormwater Quality Database (NSQD).
Action 7: Prioritize ongoing support for quantitative GSI performance monitoring, database upkeep, and timely meta-analysis of accumulated monitoring data.
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Contact Nell Green Nylen, Senior Research Fellow, Wheeler Water Institute, Center for Law, Energy & the Environment