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Attachment B Commercial & Industrial Stormwater Credit Program DRAFTver2 Purpose: The purpose of the Stormwater Credit Program is to encourage city property owners to manage rainwater in ways that help deal with problems arising from stormwater runoff in an urban environment. In Roseville, the large amount of impervious surfaces such as asphalt, concrete, roofs, sidewalks, etc., stop stormwater from naturally absorbing into the ground. The runoff from these areas transports pollutants like phosphorus, nitrogen, heavy metals, petrochemicals, fertilizer, pet waste and other common chemicals to receiving bodies of water and is a major source of water pollution in urban areas. In an urban environment, the amount of impervious area on a property is the most significant factor affecting the quality and quantity of stormwater runoff. By using stormwater Best Management Practices (BMPs) property owners can partially duplicate the effect of the open areas and wetlands that provided natural drainage prior to urbanization. The program offers Commercial & Industrial Property Owners credits based on the targeted rainfall volumes that can be kept on site. The credit will be based on capturing a 10 year (4.2 ") or 100 year (7.4 ") Type II rain event from the desired drainage area. Only the drainage area that is treated will be eligible for credit. This program does not provide credits for practices that are required by a permit. Practices that go above and beyond the permit are eligible for stormwater credits. Property owners that receive cost share funding from a watershed district, state agency, etc., are eligible for the stormwater credit program. Below is a partial list of stormwater BMPs approved for use in the Stormwater Credits Program: Raingardens, pervious pavers, wet ponds, dry wells, sand filters, filter strips, infiltration trenches, green roofs The installed BMP's will be certified by the property owner, or agent of the property owner, to show that the BMP is still functioning as designed. Certification will need to be provided, at a minimum, every 5 years after the city has approved the project. Commercial & Industrial Property owners can reduce a percentage of their annual stormwater fee by capturing these targeted rain events: 10 year, 4.2" event will reduce the annual fee by 25% 100 year, 7.4" event will reduce the annual fee by 75% Example: In 2014, a 50 acre industrial site is treating rainfall from 17 acres of their site with no discharge to the city storm sewer system. The annual stormwater fee for the 50 acre property is $36,220. Below is the breakdown of the annual reduction in stormwater fees depending on the rainfall that is captured from the 17 acres that is being captured: Stormwater Credit % Reduction $ Reduction 10 year (4.2 ") 25% $3,078.70 100 year (7.4 ") 75% $9,236.10 Updated: 19 March 2014 R: \PublicWorks\ Engineering\ Drainage \StormWaterUtility \Stormwater Credit Memo Draft ver2.docx