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TECHNICAL MEMORANDUM <br /> July 13, 1995 <br /> Page 14 <br /> on -site detention, or some related means of reducing runoff from each property. Some <br /> consider detention on a case -by -case basis, depending upon the specifics of each development, <br /> the capacity of specific drainage basins, the history of flooding, and various other factors. <br /> For Medford a combined approach to detention that includes regional and on -site facilities is <br /> recommended. The current updating of the Drainage Master Plan will determine where each <br /> approach is appropriate. Where physically and economically feasible, regional detention <br /> facilities should be emphasized over more numerous on -site facilities. Clearly, the city has <br /> the responsibility and authority for managing, operating, and maintaining regional facilities. <br /> The city's authority to implement an inspection and maintenance program over privately <br /> owned facilities is less clear, but it is an issue that must be addressed. The city needs to <br /> acquire the authority to enforce maintenance of privately owned facilities in areas of the city <br /> where master planning efforts identify the need for on -site retention as part of the overall <br /> solution to citywide drainage problems. As a minimum, the city will need to inspect these <br /> facilities to determine if the owners are performing the required maintenance. If not, the city <br /> will need to legally enforce that the work be completed or provide city crews to do the work <br /> and obtain reimbursement for those services. <br /> Where detention facilities are required, every attempt should be made to include a water <br /> quality element into the design. A dual purpose for pond facilities is easy to accommodate. <br /> In addition, the water quality elements will most likely provide benefits to wildlife. <br /> Infiltration Systems <br /> Infiltration systems are not a recommended approach for stormwater management in the city <br /> of Medford area due to the generally impermeable nature of the soils. Infiltration systems <br /> should be accepted if engineering analyses demonstrate that the approach is feasible for a <br /> particular site. The most appropriate use of infiltration systems is in residential developments. <br /> Infiltration should not be used in commercial or industrial areas because of the potential for <br /> groundwater contamination. <br /> Erosion Control Criteria <br /> Many jurisdictions require formal erosion control plans for all development projects, including <br /> residential, commercial, and industrial construction. Table 3 -5 summarizes the basic <br /> provisions fweveral communities. Essentially all have adopted moderate to eaC.tgnsive <br /> requirements for erosion control. The city of Eugene is in the process of developing more <br /> stringent requirements and are adopting interim standards beginning July 1995. They <br /> anticipate more extensive requirements within the next two years. <br /> Many jurisdictions have comprehensive guidelines or manuals available for aiding developers <br /> and city personnel in the preparation of erosion control plans. These resources are excellent <br /> references for erosion control policy and procedure. For the city's reference, copies of the <br /> J:\211 1'ask3Vm31. DRAFT <br />