Our local rivers and streams are under constant pressure from the urban and suburban environments they flow through. Historically, a combination of channelization, stormwater runoff, and wastewater effluent has severely impacted the health of our waterways. To make our waterways healthy again, stream restoration efforts are essential. In this blog post, we’ll explore why stream restoration is necessary and dive into several restoration techniques being used locally to revitalize our rivers and streams.
Why is Stream Restoration Necessary?
Human activity has heavily altered our streams. Urbanization straightened and disrupted their natural flow, leading to problems like erosion and loss of habitat for aquatic life. At the same time, a large amount of paved surface increases stormwater runoff, which carries pollutants like oil, fertilizers, and pesticides into our waterways. Wastewater treatment plants have made great strides in reducing contaminants in the treated water they discharge, but water quality alone doesn’t equate to a healthy stream.
Stream restoration restores the stream’s natural structure, which enhances water quality and creates habitat for fish, macroinvertebrates (aquatic insects), and other wildlife. In short, stream restoration tends to improve the overall health and resilience of a stream.
Techniques for Restoring Streams
Stream restoration projects use a variety of techniques, each designed to address specific problems caused by human modifications. Let’s take a closer look at some restoration techniques, along with local examples.
1. Dam Removal
Dams, especially small low-head dams, are major disruptors of stream ecosystems. They block the natural flow of water, prevent fish migration, and cause sediment to build up behind the dam, which degrades water quality. Removing dams allows streams to flow naturally and allows blocked fish to finally move upstream. Dam removal also eliminates dangerous water currents and enhances recreational opportunities like boating and fishing.
Local Example:
Two local dams have recently been removed: the Hammel Woods Dam on the DuPage River in Shorewood and the Fullersburg Woods Dam on Salt Creek in Oak Brook. These projects are restoring natural flow, increasing fish species, and creating more opportunities for recreation.
2. Stream Meandering
Many streams were straightened (or channelized) to speed up water flow and maximize usable land. However, straightening a stream increases streambank erosion and destroys habitat. Reintroducing natural curves, or meanders, slows water down, which reduces erosion and creates a variety of habitats for aquatic life.
Local Example: At Blackwell Forest Preserve and St. James Farm in DuPage County, the Spring Brook Creek restoration project reintroduced meanders to the stream.
3. Creating Riffles and Pools
One way to diversify a stream’s habitat is by creating riffles and pools. Riffles are shallow, fast-flowing sections of a stream where water tumbles over rocks, which helps add oxygen to the water and provides a habitat for fish and macroinvertebrates. Pools, on the other hand, are deeper, slower-moving sections that offer resting places for fish. Together, riffles and pools create a variety of habitats that benefit a wide range of species.
Local Example: The Fullersburg Woods restoration project constructed nine riffles in Salt Creek. These riffles diversify stream flow and habitat. Riffles are also a key component of the upcoming stream restoration project on the Lower DuPage River in Plainfield.
4. Streambank Stabilization and Habitat Creation
Eroding streambanks contribute to low water quality and habitat loss. Streambank stabilization techniques, like installing stream barbs or using rootwads (dead trees with roots attached), help prevent erosion and create new habitats for fish and other wildlife. Native plantings along the banks further stabilize the soil, make a natural buffer that filters pollutants from stormwater runoff, and provide necessary habitat for macroinvertebrates.
Local Example:
Streambank stabilization is a key priority of the upcoming restoration project on the DuPage River in Plainfield. The project aims to be “dynamically stable,” meaning the streambanks will be stabilized but allowed to naturally shift over time.
5. Floodplain Restoration
Floodplains are areas next to streams that naturally hold and absorb floodwater during heavy rains. Unfortunately, many of these areas have been developed. By restoring floodplains and wetlands, we can reduce flood risk and improve water quality by allowing excess water to filter through soil before re-entering the stream. Floodplains also provide vital habitats for plants and animals.
Local Example: The Spring Brook Creek restoration at Blackwell Forest Preserve in Warrenville connected the creek to the floodplain, which allows floodwaters to flow into the surrounding forest preserve. The Plainfield project on the DuPage River aims to control invasive species and restore native vegetation in the floodplain.
Stream Restoration: A Holistic Approach to Stream Health
Stream restoration aims to re-naturalize rivers and streams that have been heavily impacted by development. Locally, restoration projects on Salt Creek, Spring Brook Creek, and the DuPage River are already making a difference by improving water quality and diversifying habitat. Ultimately, stream restoration creates healthier, more resilient waterways that benefit both wildlife and the communities around them.
