Stormwater Pond Maintenance, and Wetland Management for Phosphorus Retention

Project summary:

This project defines, identifies, and evaluates risk factors for water bodies in the spectrum of constructed stormwater ponds to natural wetlands for water quality performance to guide their management. The main objectives are to 1) establish robust relationships between pond/wetland features and functionality through broad field assessment, directed laboratory studies and data synthesis, 2) develop a toolbox to evaluate site-specific indicators of functionality (or failure) for performance evaluation, and 3) recommend maintenance protocols for constructed stormwater ponds and constructed stormwater wetlands, and suggest management options for wetlands.

This project expands a limited understanding of stormwater pond, wetland effectiveness, and factors that affect effectiveness, and informs stormwater managers who need to evaluate and maintain constructed stormwater ponds and manage wetlands. Information from the research team's ongoing LRRB-funded "Wet Pond Maintenance for Phosphorus Retention" project also complements and supports this project.

Constructed stormwater ponds and constructed stormwater wetlands are waterbodies intentionally constructed in upland areas which retain water for flood control and settle particles and associated pollutants for burial in the sediments of the pond. Wetlands are natural water bodies. There is some evidence that wetlands and constructed stormwater ponds may not retain phosphorus deposited in the bottom sediments and are potentially exporting phosphorus to downstream lakes.

In addition to constructed stormwater ponds and constructed stormwater wetlands, there are a range of water bodies that serve the purpose of retaining stormwater, including wetlands, and un- or under-maintained constructed stormwater ponds that have abundant wetland vegetation. In areas developed without constructed stormwater ponds, wetlands can provide runoff treatment and share many characteristics with ponds, but little is known about their potential for phosphorus re-release.