Lake Renovations

Lake Impairments Overview

Since its creation in 1967, Easter Lake has faced diminishing water quality due to high sediment and phosphorus loads originating in its predominantly urban watershed. Over the years, water quality has become poor in Easter Lake. The lake has shrunk from its original size in both surface area and volume. Sedimentation and nutrients have resulted in frequent algae blooms and low water clarity. Elevated bacteria levels in the lake have resulted in swimming advisories for Easter Lake. The lake also has some undesirable fish species (Common Carp and Gizzard Shad) and has a stunted panfish population.

What is causing poor water quality?

Both external (watershed) and internal (lake) processes contribute phosphorus and sediment to Easter Lake decreasing water quality.

External sediment and nutrient sources (pollutant sources from the watershed)

Runoff and pollutants from urbanized, developing, and agricultural land
Stream bed and bank erosion

Internal sediment and nutrient sources (pollutant sources from within the lake)

Internal lake phosphorus loading
Shoreline erosion
Lake bottom re-suspension

Internal pollutant loads result from the re-suspension of lake-bottom sediment, decay of dead organisms such as fish and aquatic plants, and from the shoreline. Sediment re-suspension occurs naturally in lakes due to wind and wave action, but can be increased due to other factors, such as bottom feeding fish (e.g. carp and bullhead) that feed on lake bed vegetation. Easter Lake has also accumulated large amounts of sediment at the lake bottom over time. This increases the ability for phosphorus to mix into the water column.

In-Lake Solutions

Sediment & Nutrient Reduction

Construction of an in-lake silt dike on the western arm (Yeader Creek branch) of the lake to reduce sediment and nutrient pollution to the main body of the lake and improve overall water clarity.

Silt dike, western arm Easter Lake 2018

Shoreline Stabilization

Shoreline erosion in Easter Lake has contributed to the loss of surface acreage, depth, and habitat at Easter Lake. Shoreline erosion is a natural process that can be increased by physical factors such as wind/wave action, ice heave, recreational use, and lack of aquatic vegetation. To address shoreline erosion, key areas will be regraded and armored with a combination of riprap, Flexamat, and tall grass management and buffers.

Riprap placed near the Easte Lake boat ramp, summer 2018

riprap placed along Evergreen Ave. Rock piles for fish habitat also pictured, Summer 2018

Flexamat shoreline stabilization with vegetation starting to grow, Fall 2018

Targeted Dredging and Sediment Removal

Since its creation in 1967 Easter Lake has lost 30% of its volume. To address sediment in Easter Lake, a targeted dredging approach will be used. Targeted dredging is a vital component of the overall restoration of Easter Lake and will enhance a number of other water quality improvements. Benefits of targeted dredging include:

Increased depth in shallow areas will reduce sediment re-suspension and increase water clarity
Targeted dredging will improve fish habitat, thereby increasing the water quality benefits obtained with the fisheries renovation.

Hydraulic dredging, Easter Lake 2016

Mechanical dredging, Easter Lake

Fisheries Renovation

The Iowa DNR, Polk CCB, and Central Iowa Anglers are working to enhance the fishery at Easter Lake. These exciting improvements include shoreline stabilization and deepening, removal of excess sediment, and construction of an in-lake silt pond. Additionally, a fish rearing pond was constructed near the lake to rear Walleye fingerlings. The spillway has also been updated to include a fish barrier to prevent undesirable fish (Common Carp & Gizzard Shad) from reentering the lake. Fish habit (cedar trees, spawning beds, catfish hides, and rock piles) are currently being installed. To learn more about the fisheries renovation of Easter Lake, click here.

Fish Rearing Pond, Easter Lake

Improved Spillway, Easter Lake 2015

Catfish hides, Easter Lake 2018