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03/07/95 09:43 V503 224 7820 WOODWARD -CLYDE Wj ulsiuf: <br /> For guidance on selection, design, installation, landscaping and maintenance of ponds <br /> and marshes, it is recommended that Eugene use the City of Portland's new document: <br /> Stormwater Quality Facilities: A Design Manual (March 1995). Tom Schueler of the <br /> Centey for Watershed Protection was a key contributor to this documenuland compiled <br /> information from a variety of sources around the U.S. to develop Chapters 3 <br /> (Stormwater Ponds) and 4 (Stormwater Marshes). Schueler and his associates appear <br /> to be the most current on the subject, having recently researched numerous ongoing <br /> performance studies. The new Portland manual provides an excellent general <br /> overview, as well as general design criteria and guidelines for landscaping, <br /> construction and maintenance. Eugene will need to adapt the vegetation information <br /> to local conditions (e.g., incorporate the approved Eugene plant list). The Portland <br /> manual does not contain cost information; EPA's Guidance for Specifying <br /> Management Measures for Sources of Nonpoint Pollution in the Coastal Zone (1993) - <br /> Chapter 4-1I, Table 4 -7 should be utilized. More detail on detention design, including <br /> good examples of detention basin sizing, is contained in Stormwater Detention for <br /> Water Quality, Drainage, and CSO Management (1993)- Chapters 18, 20 and 23. <br /> Additional references which the City of Eugene should have on hand for more detailed <br /> background on these facilities and detailed (pollutant removal efficiencies are The Use <br /> of Wetlands for Controlling Storm Water Pollution (1992)- Chapter 2 and 10% Rule <br /> Compliance: Urban Stormwater Quality Guidance for the Maryland Chesapeake Bay <br /> Critical Area in Intensely Developed Areas (May 1993) - Appendix A. Schueler and <br /> his associates at the Center for Watershed Protection also continue to present the most <br /> recent findings and guidance related to ponds and marshes in the periodic publication, <br /> Watershed Protection Techniques_ <br /> Structural Facilities for Oil and Grease and Sediment Control <br /> There are four types of structural facilities which could be utilized for on -site control <br /> of oil and grease, sediments, or other debris: <br /> • OiUwater separators — multi- cham devices designed to remove <br /> hydrocarbons from urban runoff as it moves through the device. There are <br /> three basic variations of separators:: the simple spill control (SC) separator with <br /> one chamber designed to trap small spills, the American Petroleum Institute <br /> (API) separator with three chambers designed to remove sediment and <br /> hydrocarbon loadings from runoff, and the coalescing plate (CP) separator <br /> which encourages separation of materials of different densities. <br /> • Trapped catch basins — inlets to the storm drain located between the curb and <br /> the underground storm drain line. They include a small trap below the pipe <br /> S \945042na \task0200 \onsite controls \techmcm.ck 112 <br />