Developed areas, as compared to undeveloped areas, generally have increased imperviousness, decreased infiltration rates, increased runoff rates, and increased concentrations of pollutants such as fertilizers, herbicides, greases, oil, salts and other pollutants. As new development and redevelopment continues in Town of Dyer, measures are needed to intercept and filter pollutants from stormwater runoff prior to reaching regional creeks, streams, and rivers. Through the use of Best Management Practices (BMP), the Town of Dyer has adopted a policy that the control of stormwater quality will be based on the management of Total Suspended Solids (TSS).
Another major source of pollution in many Indiana streams, including those within the corporate boundaries of the Town of Dyer, is the streambank erosion associated with urbanizing watersheds. Stream channels develop their shape in response to the volume and rate of runoff that they receive from their contributing watersheds. Research has shown that in hydrologically stable watersheds, the stream flow responsible for most of the shaping of the channel (called the bankfull flow) occurs between every one (1) to two (2) years. When land is developed, the volume and rate of runoff from that land increases for these comparatively small flooding events that are not normally addressed by the detention practices and the stream channel will adapt by changing its shape. As the stream channel works to reach a new stable shape, excess erosion occurs. As new development and re-development continues within the corporate boundaries of the Town of Dyer, measures are needed to minimize the impact of such development or re-development on streambank erosion. Through the use of appropriate Best Management Practices (BMP's), the volume and rate of runoff for channel forming flows will be reduced in an attempt to minimize increased streambank erosion in the receiving streams and channels.
The project site owner must submit to the Town of Dyer, a SWPPP that demonstrates placement of appropriate BMP(s) from a pre-approved list of BMPs specified in the Town of Dyer Stormwater Technical Standards Manual and SWQMP. The noted BMPs must be designed, constructed, and maintained according to guidelines provided or referenced in the Town of Dyer Stormwater Technical Standards Manual and SWQMP. Details regarding the procedures and criteria for consideration of acceptance of BMPs other than those specified in the pre-approved list are provided in the Town of Dyer Stormwater Technical Standards Manual and SWQMP.
Gasoline outlets and refueling areas must install appropriate practices to reduce lead, copper, zinc, and polyaromatic hydrocarbons in stormwater runoff. These requirements apply to all new facilities and existing facilities that replace their tanks, regardless of the size of the facility.
Discharges from new development and redevelopment sites are not allowed directly into karst features without pre-treatment. (Ord. No. 2021-32, §1, 11-10-21)