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08,'22/95 TUE 09:40 FAX WOODWARD CLYDE 4j004 <br /> 2.0 ON -SITE AND REGIONAL CONTROLS <br /> Stormwater quantity /quality controls for new development generally consist of some type <br /> of storage and/or treatment facility such as retention basins, detention basins, ponds, <br /> infiltration facilities, grass swales, filters, and/or constructed marshes. These types of <br /> facilities can be constructed on -site to control drainage from a specific development or <br /> off -site at strategic regional locations to control drainage from several developments. <br /> Figure 1 provides an example which illustrates the difference between on- site and <br /> regional controls. <br /> On -site facilities are usually privately constructed and owned. They are typically <br /> constructed at upstream locations in a watershed, and they are used to control drainage, <br /> reduce the occurrence of flooding, and/or to treat pollutants from a specific development <br /> which includes a relatively small drainage area (i.e., approximately 1/2 to 20 acres). <br /> Regional facilities are usually publicly constructed, owned, and maintained. They are <br /> typically constructed at locations farther downstream in a watershed, and they are used to <br /> control drainage, reduce the occurrence of flooding, and/or to treat runoff from relatively <br /> large drainage areas (i.e., approximately 20 to several hundred acres). <br /> Hydrologic/hydraulic models of a watershed are typically used to find the most <br /> appropriate sites for these types of facilities. <br /> Currently, the City of Eugene does not have any policies regarding the application, use, <br /> location, and design standards for on -site and regional controls. As a first step in creating <br /> standards for new development, the City of Eugene would like to establish a policy <br /> framework to help guide the development of standards for the use of on -site and/or <br /> regional facilities for stormwater. There are many issues to consider with respect to the <br /> use of on -site facilities, regional facilities, or combinations of the two. These issues are <br /> described in the following section. <br /> 3.0 ISSUES ASSOCIATED WITH THE USE OF ON -SITE AND /OR <br /> REGIONAL CONTROLS <br /> The following text provides a summary of the significant issues with respect to the use of <br /> on -site and/or regional facilities. The issues described include: 1) finding suitable <br /> locations for facilities, 2) effectiveness of facilities for water quality control, 3) <br /> effectiveness of facilities for flood control, 4) maintenance of facilities, 5) inspections and <br /> enforcemept, and 6) funding. Descriptions of the advantages and disadvantages.. -- <br /> associated with each issue are based on technical literature and interviews with <br /> approximately fifteen jurisdictions that have been in the process of revising or have <br /> recently revised their stormwater standards for new development. A reference list of the <br /> jurisdictions is provided in Section 6.0 of this memo. (Note: A table which provides a <br /> bulleted summary of the advantages and disadvantages is provided in Attachment #1.) <br /> 3 <br />