Construction Site Erosion Control Demonstration for Roads
Ashland Bayfield Douglas and Iron County Land Conservation Department
Basin Program Funds:
The unique red clayey till soil and steep slopes of the Lake Superior basin
combine to create an area that is highly susceptible to erosion. Given these
factors, road construction is a significant contributor of nonpoint source pollution
to Lake Superior and its tributaries. Cost-effective erosion control alternatives
for roadway stabilization in Wisconsin's Lake Superior coastal counties are
Road maintenance and construction have been an historic concern with resource
managers in the Lake Superior coastal counties of Ashland, Bayfield, Douglas
and Iron. Steep slopes combine with natural drainage ways and unstable red clayey
till soil to contribute to the instability of road construction sites. A number
of studies at the federal, regional and local levels have identified proper
planning and maintenance of road construction sites as a priority in controlling
nonpoint source pollution to the lake. Educational programs which promote proper
construction site design as well as application of construction site erosion
control best management practices (BMPs) were also identified as priority activities.
The Ashland, Bayfield, Douglas and Iron Land Conservation Department assembled
a review team to evaluate possible demonstration sites, of which five were reviewed.
The review team selected two sites, one in Douglas County and the other in Bayfield
The project team planned, designed and constructed erosion control measures
for the Douglas County site. This included 14,256 linear feet of road ditch
shaping and seedbed preparation, 6 ½ acres of roadside seeding and mulch, 1,420
and 1,800 linear feet, respectively, of high velocity and regular erosion control
matting placed and anchored, four culvert inlet and outlet protections of non-woven
geotextile, rock and matting, and 90 linear feet of channel lined with non-woven
geotextile and rock.
The Bayfield County site included 2,500 linear feet of road ditch shaping,
330 linear feet of silt fencing, 23.7 tons use as outlet protection, one culvert
replacement (rebedded and packed), one acre seeding and one acre of mulch, non-woven
geotextile for firm outlet bed, and erosion control matting placed and anchored.
The Douglas County road ditch deposited water and sediment directly into Lake
Superior, while the Bayfield County project formerly deposited sediment into
an intermittent stream, to a trout stream, and eventually to Lake Superior.
As a result of the project, road maintenance costs should be reduced. More importantly,
changes to road ditch engineering have reduced runoff peak flows, added vegetation
filters runoff and reduces the sediment load to the water. Results indicate
that at the Douglas County site an estimated 950 tons of soil were saved by
installing these erosion control practices, and an estimated 305 tons of soil
were saved on the Bayfield County site. Over 200 elected officials, road crews
and contractors have toured the two demonstration sites.
Contact: Ashland Bayfield Douglas and Iron County Land Conservation Department, (715) 682-7187