Soft Shoreline Engineering Case Studies
Rouge River at Shiawassee Park - Site #38
Farmington Hills, Michigan
Project Goals and Objectives: Stabilize the riverbank with soft engineering techniques and woody debris, create an adjacent buffer zone of native plants, and enhance aquatic habitat
Project Description: The Upper Branch of the Rouge River is home to the redside dace (Clinostomus elongatus), a state threatened minnow that requires cold, clear water and is found in only one other Rouge tributary, the Johnson Creek. Like most of the Rouge, the Upper Branch suffers from high flow variability and stormwater pollution. Land use changes with residential development replacing open land in the headwaters of the Upper Branch have increased the amount of impervious surfaces, reducing the land’s ability to absorb and filter stormwater, causing unstable flows. Increases in impervious surfaces can be directly linked to a decline in the biological integrity of streams, according to the Center for Watershed Protection. The huge surges in flow that follow rain and snow melts cause streambanks to erode and sediment to be deposited in the river and downstream. As stormwater pollution warms the water, reduces clarity and erodes away the vegetation that shades the river, the Upper Branch is losing its ability to support the redside dace.
Shiawassee Park in the City of Farmington encompasses about a half-mile of the Upper Branch of the Rouge River. It is a multi-use, 26-acre park which has a heavily-used walking trail along the river, tennis courts, a baseball field, and a heavily-used children’s playscape. Much of the park was mowed, providing little in the way of a buffer zone for the river. Streambanks were eroding and gabion baskets had been used to stabilize a section of stream.
Friends of the Rouge (FOTR), in conjunction with the City of Farmington, were awarded a grant from the Great Lakes Commission to create a buffer zone of native plants, eight meters wide (25 feet), along 23 meters (75 feet) of riverbank. Additionally, woody debris and soft bioengineering were used to stabilize the bank.
The City of Farmington prepared the site by re-grading the bank and creating a fascine shelf, removing turf grass and adding compost, and dropping a dead ash tree into the stream. FOTR volunteers moved the tree into position, secured it to the bank to stabilize the toe of the slope, and added additionally woody debris. Use of a dead ash tree demonstrates an inexpensive re-use of a readily-available material, made possible by the recent invasion of the Emerald Ash Borer that is killing most of the ash trees within Southeast Michigan.
In September 2004, a group of almost 50 volunteers including Master Gardeners, Boy Scouts, the Farmington Riparian Stewards, and FOTR volunteers installed over 900 native plants in the buffer zone. The City of Farmington Hills provided a Grow Zone sign. In November, a smaller group of volunteers installed a row of red-osier dogwood fascines in the re-graded bank and covered them with soil from the re-grading. The City of Farmington installed a split-rail fence around the buffer. This project improved the health of the stream at a minimal cost by creating a buffer zone and stabilizing the bank using natural materials that also provide wildlife habitat. Using volunteer labor and installing interpretive signs helped to educate local residents about good riparian practices. The cooperation of a local non-profit, a municipality, and local volunteers is an effective strategy at improving the health of the river while simultaneously creating better river stewards.
Cost: The total cost of the project was $10,723.00, matched with $2,950.00 in volunteer labor and City support, so that actual cash expenditures were $7,773.00. A grant from the Great Lakes Basin Program for Soil Erosion and Sediment Control covered the costs. The costs fall well below the industry average for this type of project due to the volunteer labor and support.
Partners: City of Farmington, City of Farmington Hills, Michigan Department of Environmental Quality, Friends of the Rouge, Farmington Riparian Stewards, Riparian Corridor Management Work Group, Master Gardeners, Environmental Consulting & Technology, Inc. and the Boy Scouts
Ecological effectiveness: Prior to restoration, the streambank was eroded with grass mowed to the edge. The buffer zone now includes 43 different species of native plants. Butterflies and other pollinators are now using the area. For the first time, a very sensitive type of dragonfly larvae (Gomphidae) was found at this site in a dragonfly survey. Invasive species in and around the site have been almost completely eliminated.
Restoration Contact: Friends of the Rouge at (313) 792-9621