Admin Order 58-12-14 - Laserfiche WebLink

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Lane County Fairgrounds). Development in approximate A Zones is required to meet the same City and County development standards as those in areas where detailed studies have been conducted, with just a few differences. Where detailed studies have been conducted, the hundred year water surface elevation is determined by FEMA (the expected water surface elevation corresponding to a statistical flooding event that has a one percent chance of occurring in any given year), and a floodway is designated. For approximate A Zones, the best available data from an authoritative source is used where possible to determine the 100 -year water surface elevation, and when good data is not available the applicant is responsible for determining the 100 -year elevation using a FEMA approved method, which is then evaluated by City staff. Larger developments, such as subdivisions over five acres or fifty lots are required to provide detailed hydrological analyses. Floodplain development regulations are the same in either case (detailed study areas vs. approximate A Zone areas) except that approximate A Zone areas do not have designated floodways. Floodways are intended to remain unobstructed to convey floodwaters out of our community, are typically associated with high velocity flows, and have significant encroachment provisions. The City and County floodplain development standards would not significantly change as a result of a detailed floodplain analysis in areas now designated as approximate A Zones, with the exception of floodway development prohibitions. However, for the City of Eugene, regulations regarding watercourse alterations at Eugene Code Section 9.6707 protect the flood carrying capacity of some rivers and streams that have no designated floodway. Other regulations often apply to development within the floodplain such as federal and state wetland regulations, and local natural resource and water quality waterway protections. Topic; Development Standards /Low Impact Development No development standards proposed in the Basin Plan for future development. Instead of collecting and treating stormwater on a municipal scale, maximize on -site infiltration, and require that post - development flows equal pre - development flows for new development. Require prioritization of non - structural BMPs over engineered facilities. Basin plan does not assess or recommend LID standards. Require low impact development standards [RR -11, [RR -21, [SC -101, [SC -141 The RR -SC Plan supports the implementation of city -wide Stormwater Development Standards, for much the same reasons they were proposed by the other 2002 basin plans: mainly, that on- site stormwater controls are the most cost - effective way to deal with the water quality impacts of new development. Municipal -scale collection and treatment of stormwater is not being proposed. Retrofitting the existing municipal system through capital projects is another element of the city -wide water quality strategy, but it is more targeted to collection /treatment in high pollutant source areas and opportunistic restoration /rehabilitation of the open and piped system to incorporate water quality features, and is not wholesale collection and treatment. RR -SC Stormwater Basin Plan Comments Pg.6 of 17