From the moment this project was first proposed in the Spring of 2013, neighbors and the Dudgeon-Monroe Neighborhood Association (DMNA) were concerned that sediment and phosphorous-laden storm water would drain off of the site above and run into the nearby beloved Lake Wingra which is within sight of, and just two blocks downhill from, this site on Monroe Street. Anyone familiar with the area knows that soil leaving the site will run down the nearest storm drain and directly into Lake Wingra.
Other neighborhood concerns included: 1) traffic congestion; 2) impacts of the development on the already-limited residential parking on the area’s tiny streets; and 3) intrusion of the commercial development into a residential community. To learn more about the controversial development click here for a background article and here for a more recent update.
Soil Erosion and Small Construction Sites (<5 acres)
Soil erosion from construction sites has long been recognized as a major source of soil sediment and other suspended solids found in storm water runoff in many parts of the country (Hagman and others, 1980). Historically, the focus of Federal and state erosion control regulations has been on sites 5 acres or larger. But since the 1990’s small construction sites–those of fewer than 5 acres–have been recognized for their significant contribution to the soil erosion and lake sedimentation problem. Starting in 2012, construction sites smaller than 5 acres are now subject to Federal and state regulations that mandate an erosion control plan. Even so, some sites smaller than 1 acre (like our project site on Monroe Street) may be exempted from these requirements by local (City of Madison) authorities. (See here for more information on this exemption clause)
Dane County Study Details Soil Erosion Contribution from Small Sites
Soil erosion is a concern during the active demolition and construction phases of projects on sites like the one above because the soil is bare and subject to wind and water erosion or being picked up on the tires of construction vehicles and tracked into city streets. In a 2000 study by the U.S. Geological Survey (USGS) designed to “evaluate the significance of erosion on construction sites less than 5 acres as a source of sediment to surface waters” examined a small residential site (0.34 acres) and a small commercial site (1.72 acres). The study concluded that the sites were a “potential source of large amounts of sediment erosion loads that were 10 times larger than typical loads from urban and rural land uses in Wisconsin.” USGS Fact Sheet FS-109-00 U.S. Geological Survey August 2000
Because of these concerns, contractors are now usually required by the City of Madison to file an erosion control plan and stipulate what measures they will take to prevent soil loss, unless perhaps the site is smaller than 1 acre. Common erosion prevention steps include silt fence, straw bales, or silt socks. But as demolition of the former Town & Country Auto Repair began last week there was no evidence of a single common-sense step to prevent soil erosion. Likewise there was no evidence of tracking pads, large industrial-strength door mats, designed to scrap soil from vehicles and keep it on site
Conclusions and Recommendations
Here on Monroe Street there is a construction site that may have fallen through the regulatory or supervisory cracks because it does not meet a minimum 1 acre size or because local authorities do not recognize the significance of the potential harm erosion from this site can cause to nearby and downstream Lake Wingra.
Because Lake Wingra drains to Lake Monona by way of Wingra Creek. And because the Wisconsin Department of Natural Resources (WIDNR) has proposed adding Lake Monona along with other lakes in the Yahara chain to the list of Impaired Waters it would seem prudent, if for no other reason than helping Lake Monona, that the City of Madison should do everything possible to limit sediment loads to Lake Wingra. Especially on an obvious and “easy call” like the Monroe Street project.
Hagman, B.B., Konrad, J.G., and Madison, F.W., 1980, Methods for controlling erosion and sedimentation from residential construction activities,in National Conference on Urban Erosion and Sediment ControlInstitutions and Technology, October 10-12, 1979, St. Paul, Minnesota: U.S. Environmental Protection Agency Report EPA-905/9-80-002, January, 1980.,p. 99105.
Soil Erosion from Two Small Construction Sites, Dane County, Wisconsin. U.S. Department of the Interior USGS Fact Sheet FS-109-00
U.S. Geological Survey August 2000