To evaluate the effectiveness of BMPs in reducing pollutant (sediment, phosphorus) production on roads and delivery to streams, we are monitoring a set of road segments in the towns of Duxbury, Fayston, Waitsfield and Warren, Vermont. On each road segment, we have selected a site to be “treated” with a BMP, and a nearby segment to be held as a “control.” Over a period of 2-3 months, we are monitoring sediment runoff from the road segments by capturing material in a silt fence, positioned in the road ditch or at a culvert outlet. Following storm events, we visit sites, excavate sediment deposited in the fence, and return a subsample to the lab for analysis.
Following a pre-treatment monitoring period, we will install one of four BMPs (stone-lined ditch, check dams and turnouts, compost socks, hydro seeding application) on the “treatment” site, then continue monitoring here and at the control site. Any change in erosion at the treatment site, relative to the control, will be attributed to the effectiveness of the BMP.
Our silt fence design is shown below. Photos of project road segments and the silt fences in action are shown on the Road Sites tab.
The objective of this design is to catch the possible sediment running off the roads through their respective culvert outlets. Water will flow through as the filter fabric traps sediment back and allow it to settle.
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