The Nine Mile Creek Watershed District partnered with the City of Edina to implement stormwater improvements of the Lynmar Basin in Bristol & Mavelle Park in Edina.

Project Goals

  • Improve the water quality of Lake Edina and downstream water resources
  • Reduce flood risk in the South Cornelia neighborhood
  • Enhance natural resources, including improving pollinator habitat
  • Keep a portion of the space open for passive recreation

    Water pooled in swale, cloudy sky in the background. Water loving plants stick above the water line.
    Basin filled up with stormwater collected from France Avenue and other nearby roads following a rain storm. Within 24 hours, the stormwater infiltrated into the ground.

This project is part of the larger Lake Cornelia & Lake Edina Improvement Project.

Project Summary

Originally, Lynmar Basin was a dry pond that collected stormwater from an area of about 20 acres. A dry pond provides storage for flood waters, but provides few water quality benefits. Due to this, NMCWD and the City of Edina worked with the community to plan and design a basin retrofit. The basin retrofit not only treats stormwater but also provides additional flood storage capacity and creates native habitat.

The retrofit involved lowering the basin floor by about one foot so it is below the stormwater outlet pipe, in addition to other steps. This holds more stormwater in the basin which can then soak into the soil over a few days. Filtering the water through soil helps remove pollutants. Additional water was also directed to the basin to increase the treatment area from 20 acres to about 36 acres. See the treatment and water storage benefits below:

Table showing flood storage and pollution benefits of the retrofit

Legacy Logo

Studies and Reports

Lynmar Basin Feasibility Report


The District has received grant funds from the Minnesota Board of Water and Soil Resources through the Clean Water, Land and Legacy Amendment, for planning, design and construction work of the project to offset capital improvement funds used by the District to implement the project.

More information

Check out the Better Together Edina website for additional information on this project: bettertogetheredina.org/bristol-mavelle-park


Contact Brett Eidem, Natural Resources Project and Planning Manager, e: beidem@ninemilecreek.org  p: 952-356-1999.