Stream restoration is the the return of an ecosystem to a close approximation of its condition prior to disturbance. However, given the amount of development in Lake County, stream restoration is generally not feasible with the changes in hydrology that have occurred. Therefore, SMC uses the term stream restoration to refer to streambank stabilization and stream naturalization that may also incorporate pool riffle complexes. In many cases when streambanks are being stabilized it’s also a good time to incorporate pool riffle complexes into the stream.
- Improves water quality.
- Increases and improves aquatic habitat.
- Slows water down to allow sediment to drop out.
Streambank erosion is a major contributor to poor water quality, increased risk of flooding, and poor aquatic habitat for Lake County streams. However, a number of techniques that range from soft, naturalized solutions such as native vegetation to hard solutions like rip-rap are being used to stabilize eroding streambanks.
The preferred technique combines both soft and hard. Soil bioengineering utilizes deep-rooted native plants as the primary component. Native vegetation in combination with structural measures (such as coconut rolls, A-jacks and lunkers) are used to stabilize where higher volumes and velocities are seen. In cases where the volume and energy of the stormwater flow is extreme, rock outlet protection or riprap may be the most effective technique.
Pool riffle complexes are designed to direct the flow towards the center of the channel. Pool riffles can increase the diversity of habitat available in the stream by adding deeper water pools and by adding oxygen to the water as it flows over the riffle. A riffle allows the flow to slow and sediment to drop out of the water column.
Permits are likely to be required for streambank stabilization projects and instream pool riffles. These types of projects should be designed and installed by professionals.
- Streambank Stabilization Manual
Stream restoration before/after: Seavey Ditch Restoration Project, Vernon Hills, IL
A-jacks: Cunniff Park, Highland Park, IL
Pool riffle: Bull Creek, Beach Park, IL