Enhancement and Validation of a Stormwater Pond Assessment Tool

This project is focused on testing and improving an existing Pond Assessment Tool, which was developed by the authors in a previous project and designed to use readily-available spatial, water quality, and pond data to indicate risk and provide estimates of high water column phosphorus,sediment phosphate release, and anoxia in ponds treating stormwater. A beta version of the Tool was well-received by that project’s Technical Advisory Panel, but further workshops were not feasible underthat project. To make the Tool truly useful to stormwater practitioners, we see three research activities as particularly necessary: (1) additional analysis of existing data to develop a pond water balance component in the Assessment Tool; (2) validation of the Tool by testing on ponds with sufficient data and independent estimates of key outputs (pond total phosphorus concentration, anoxia, sediment phosphorus release); and (3) additional workshops to reach a wider audience and solicit feedback to improve the usability and outputs of the Tool, including a framework for using the Tool in prioritizing monitoring and maintenance of ponds. A key output of the proposed work would be a public version of the Pond Assessment Tool; with components for dissolved oxygen status and hydrologic retention of ponds, the Tool has potential applicability to runoff pollutants other than phosphorus as well. We will partner with the city of Minneapolis in all project tasks, making use of their intensive pond data collection efforts, which are relevant to both development and testing of the Tool's components.

Project Outcomes:

  • An initial public release of a spreadsheet-based Pond Assessment Tool that will provide stormwater practitioners in the state with a robust, straightforward means to assess a large number of stormwater ponds efficiently, using readily available spatial data, water quality data, and other pond information to predict pond water TP concentrations, oxygen levels, sediment phosphate release, and hydrology (retention or water level dynamics).
  • A better understanding of hydrologic behavior of stormwater ponds from analysis of time series of water level data in roughly 15-20 ponds in Minneapolis (MN) and surrounding cities, to be incorporated into the Pond Assessment Tool and provide a more comprehensive assessment of pond phosphorus removal efficiency.
  • Workshops with groups of potential Pond Assessment Tool users (stormwater practitioners) that will guide development of a framework to use the Tool to prioritize pond monitoring, maintenance, and/or management activities, providing benefits to practitioners in terms of more efficient and effective use of their limited resources.