CEC Leverages Low-Tech Process-Based Restoration Strategies for Mitigation in Summit County, CO

This is a view of Soda Creek after the restoration project.
(Photo courtesy of the National Forest Foundation)

Beavers have long been known as “ecosystem engineers.” These busy creatures alter, manage, and often improve the ecosystems in which they live. In Summit County, along Soda Creek, near Keystone, Colorado, the beavers did a pretty good job managing the ecosystem, until people arrived and disrupted the delicate balance.

Now, CEC and its teaming partners have a hand in returning that ecosystem back into the paws and teeth of the beavers.

The Soda Creek Mitigation & Wetland Restoration Project focuses on ecological restoration and habitat enhancement. It aims to address environmental impacts from development or land use changes, involving wetlands, streams, and the surrounding ecosystem. The land is owned by the National Forest Foundation (NFF).

Westervelt Ecological Services (WES) handled the resource delineation, groundwater well installation and monitoring, permitting, and construction for the project working closely with CEC and the NFF.

Pre-construction stream bank erosion and incision was measured.

Comprehensive Data Collection and Engineering Design

Contracted by WES, CEC performed baseline design data collection, survey including an aerial flight with drone technology to collect topographic data, on-the-ground geomorphic survey, engineering, and design plans, and two-dimensional hydrologic and hydraulic modeling within the headwaters of Soda Creek. The project generated compensatory wetland mitigation credits for the first In-Lieu Fee Program in Colorado referred to as the Western Slope ILF program, sponsored by the NFF.

This is a relic beaver dam area.

Christy Mower, a Certified Ecological Restoration Practitioner and leader of the stream restoration group in CEC’s Ecological Sciences practice in Pittsburgh, says this project is one of the first low-tech process-based restoration projects used for mitigation purposes in Colorado, which will add significant ecological value and benefit to the watershed. She and the survey team were on site in July 2022, walking the property and gathering information to begin the design and engineering process.

Key components of the project include:

1. Habitat Restoration: Rehabilitating native plant communities and improving biodiversity.
2. Water Quality Improvement: Enhancing and re-establishing wetland complexes by reactivating the adjacent floodplain to store and filter sediments and water.
3. Wildlife Protection: Creating and maintaining habitats for local wildlife species, including aquatic and terrestrial organisms, as well as adding benefits to wildfire protection.
4. Monitoring and Maintenance: Establishing long-term monitoring to evaluate the project’s performance criteria to meet goals and to adaptively manage the site.

This approach is a simple, cost-effective restoration technique using hand-built solutions to repair degraded systems. The strategy included the design of simplified structures with limited equipment, including predominately manual or hydraulic post ponders and existing on-site woody materials to build the structures.

This is the area before the restoration project.

This is the area after restoration.
(Photo courtesy of Westervelt)

The aim was to install Beaver Dam Analog (BDA) and Post-Assisted Log Structures (PALS) — human-made structures designed to mimic the form and function of a natural beaver dam.

A team of volunteers and Westervelt employees has constructed 153 structures on site. According to Mower, relic beaver dams were found upstream in the Soda Creek watershed immediately adjacent to the project, providing an ideal reference condition to model and gear the design strategy. The locations of the new structures were determined by analyzing the number, size, and spacing of these relic dams.

BDAs allow sediment and water to be stored and trapped, sealing the structure, while the adjacent floodplain and valley floor naturally floods to reactivate the floodplain surface.

By reactivating the floodplain surface, primary vegetation production will naturally recruit and reproduce native species, flooding out invasive species. 

Monitoring for Sustainable Ecosystem Management

Mower says there will be 5-10 years of monitoring to evaluate aspects of the project to determine if they are functioning as designed. “The goal is to eventually relocate beavers back into the watershed to effectively manage the ecosystem again and make our human-made structures even better,” she adds.

With the success of the Soda Creek project, CEC is actively involved in similar projects in Ohio and Pennsylvania.

“This approach provides another tool in our toolbox for restoration,” Mower concludes.