1995-04-27_AgendaPacket - Laserfiche WebLink

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PART II. -PROJECTS Y Catch Basin Sediment Filter Bag Test Project This is a cooperative project between the City of Roseville and School District 623. Dalgren, Shardlow and Uban are the development consultants hired by School District 623 to represent the District's interests in this matter. The purpose of this project is to test the usefulness of a newly patented sediment retention device (U.S Patent No. 5372714) called the "Siltsack" for application as a BMP in Minnesota cities during residential construction. The device is designed to be installed in newly installed catch basins in curb and gutter applications to serve as a secondary treatment measure to compliment primary site erosion control measures. The Siltsack is made of durable nylon fabric and is designed to filter out sediment that enters a typical storm sewer catch basin. It is available in two flow capacities, 200 gpm and 40 gpm. The manufacturer claims that it has been used as a primary erosion control measure for some applications and as a long term BMP practice in some envronmenatally sensitive areas. The product has many potential beneficial attributes but has not been tested in the midwest to date. They include: 1. If properly maintained, it may prevent the need of having to do remove sediment deltas at discharge sites in wetlands and lakes that are difficult to maintain. 2. It provides an effective method of reducing sedimentation caused by new developments at the critical stage between when the curb and gutter is installed and when all the contributing watershed is not stabilized by permanent erosion control. 3. It affords easy access from the street using a backhoe. 4. Silt collected could be disposed of at the most probable nearby area that is the source of the sediment for areas under construction. 5. The product has possibilities of collecting sediment from street sanding and leaf litter during winter and spring runoff in small watershed areas that are environmentally sensitive. The project would be applied and tested over a two year period during the development of a 77.5 acre residential development Independent School District No. 623 will be constructing during the 1995 and 1996 construction seasons. The school district would install the sacks. Inspection and maintenance responsibilities would be shared between the city and the school district on a mutually agreeable schedule. Expected outcomes include the following: A. A practical critique from the perspective of a city engineering department and a developer on the value of the product as an erosion control BMP for urban areas of Minnesota.