Streambank Stabilizations

Project Overview

Easter Lake was built in 1967 with a surface area covering approximately 178 acres. The watershed area that drains to the lake is comprised of approximately 6,500 acres. The lake is situated within Easter Lake Park, which is owned and managed by Polk County, and Ewing Park, which is owned and managed by the City of Des Moines. The lake and surrounding park offer a variety of quality of life opportunities including fishing, boating, picnicking, walking trails, wildlife watching, and swimming.

Over the years, water quality in Easter Lake declined to unsatisfactory levels. The surface area and water volume in the lake had shrunk considerably from its original size. Sedimentation and nutrients resulted in frequent algae blooms and low water clarity. One of the driving factors contributing to the degradation of Easter Lake is sediment erosion of the tributaries that feed into the lake.

Since its creation, Easter Lake has lost 30% of its volume due to siltation. Analysis of the watershed estimated nearly 60% of sediment deposited in Easter Lake resulted from stream bank erosion, primarily along Yeader Creek.

In an effort to prevent future sediment deposition into Easter Lake, the first phase of the Yeader Creek Stream Stabilization Project was completed in 2017. In total, an estimated $15-$18 million dollars will have been invested by the project partners for the improvements in the Easter Lake watershed once all major improvements have been completed.

Easter Lake Park Streambank Stabilization Project

In 2016, a basin was constructed near the historic covered bridge to capture sediment coming into Easter Lake from an unnamed tributary. While working on the sediment basin, project coordinators discovered severe erosion originating upstream in the tributary. Hidden by trees and overgrowth of invasive plants, the tributary was found to be very actively eroding sending large amounts of sediment directly into Easter Lake’s center arm. In 2017, project coordinators surveyed the eroding channel and found two large nick points with drops of an immediate 10 feet in elevation. Overall, the channel dropped nearly 30 feet in elevation over 110 yards. Honeysuckle, and other invasive species had taken over the area making the soil easily susceptible to erosion.

Yeader Creek Streambank Stabilizations

Yeader Creek is the main water source for Easter Lake. Starting near the Des Moines International Airport and Fleur Drive, Yeader Creek runs west to east through the middle of the Easter Lake Watershed all the way to Easter Lake. Most of the water in Yeader Creek comes from stormwater runoff from the surrounding urban landscape. As of 2017, two stabilization projects have been completed. The first of the two projects, YC-14, stabilized a total of 2,600 feet of stream bank. The stabilization of this section is estimated to reduce 234 tons of sediment loading per year and 304.2 pounds of phosphorus loading per year. The second project, YC-8, stabilized 2,200 feet of stream bank which will in turn help to reduce 396 tons of sediment loading per year and 514.8 pounds of phosphorus loading per year.