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03/07/95 09 :38 TT 503 224 7820 WUUDWAKV -CLYVt WJ V 3i v... <br /> 2_ The increase in volume and peak rates of runoff caused by the transition from <br /> natural surfaces to impervious surfaces in newly developed areas creates <br /> downstream water quality and flood control problems. <br /> — <br /> 3. �+r The City of Eugene currently has standards for stormwater quantity (i.e., flood) <br /> control, but has no standards 'for water quality control. An interim water <br /> quality control recommendation (e.g., a water quality design storm, so that <br /> applicants can compute the water quality treatment volume) should be <br /> developed and made available to permit applicants when the interim guidance is <br /> used by City staff. The design storm standard should then be in place when <br /> the final technical guidance manual is published. <br /> 4. There is a need to provide a consistent set of guidance to developers, engineers <br /> and designers in the private sector regarding the selection and design of on -site <br /> controls for water quality and flood control. Currently, permit applicants <br /> receive varying responses depending on the City staffperson that they talk to. <br /> 5. There is a need to provide guidance to contractors and property owners <br /> regarding proper construction and maintenance of the facilities to ensure <br /> optimum continued performance. <br /> 6. There is a need to provide guidance to property owners (particularly <br /> commercial property owners) who wish to disconnect impervious areas on their <br /> sites as a means of lowering their stormwater fees. For instance, where are dry <br /> wells acceptable; how should they be designed, installed and maintained? <br /> 7. Engineers and designers are well- accustomed to designing on -site facilities to <br /> control stormwater quantity (i.e., flood control), but have less experience <br /> designing and using water quality facilities. In general, permit applicants and <br /> public agency staff are hesitant to design and construct innovative facilities that <br /> don't have a great deal of proven performance data or that have not yet been <br /> applied locally. *As a result, a few "well- known" water quality facilities (e.g., <br /> oil /water separators) are used extensively; perhaps there needs to be <br /> consideration of other alternatives for the unique site conditions. <br /> 8. Design of water quality facilities is a rapidly evolving practice and numerous <br /> performance studies are being conducted in the U.S. at this time. When the first <br /> technical manuals were published in the 1980s, our expectations about <br /> performance were based largely on theory. These expectations have since <br /> changed due to an increased understanding from practical field application. For <br /> this reason, state -of- the -art guidance is required and there needs to be a <br /> S\945042na \task0200 \onsite controls \techmem.ck 3 <br />