Easter Lake Park Channel Restoration – Polk County Conservation

Polk County, IA | Water

Overview

Through a multi-partner effort between Polk County Conservation (PCC) and Polk County Soil and Water Conservation District, ISG developed a comprehensive restoration plan for the south entrance of Easter Lake Park to stabilize the channel.


Opportunity

Easter Lake Park provides an array of conservation and recreational opportunities. However, there were areas of concern that were impacting the integrity of the Park, including a degraded waterway, undermined banks, an entrenched channel, elevation drops, and sediment that was washed into the newly dredged lake.

Solution

ISG was the first firm in the state of Iowa to use the Iowa Department of Natural Resources (DNR) River Restoration Toolbox (Toolbox) in the natural channel design. The Toolbox integrates a series of best practices to assist designers in stream stabilization and restoration projects and utilizes techniques that emphasize the use of natural materials. Offering a consistent, relevant assessment method and reviewable design checklist, the Toolbox aided in decision-making among ISG’s multi-disciplinary team and stakeholders.

Offering a breadth of expertise, ISG’s water resource team combined specific elements that contributed to a cohesive park and lake design synthesis. For the gateway to Easter Lake Park, it was important to incorporate enhanced aesthetics and features that allowed visitors to engage with the whole environment. The design included trails and lookouts, boulder seating areas, and intentional native plantings. A bioretention basin was incorporated to provide water quality improvements and a designated space for educational opportunities.

Restoration of the channel focused on three main goals: 1) allow the channel to function and flow naturally, 2) reconnect the channel to a stable, active floodplain, and 3) integrate features that have the flexibility to evolve with the channel while still maintaining the integrity of the system. To achieve these goals, ISG performed a thorough investigation and analysis of the channel degradation and restored the channel by sizing the bankfull channel height and width, setting the bankfull elevation, and stabilizing the drop structure to reengage with the floodplain.

Today, visitors to Easter Lake Park no longer need to move beyond the entrance to find native wonder; instead, they are immediately immersed in nature’s magnificence. Native grasses spring up on the banks of the channel and Iowa wildflowers bloom on the plains. What was once a degraded eyesore has been transformed into a robust riparian system.


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