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VI-4 The specific direct1o~ given for the Phase B work was as follows; Reaches 1, 2, 3, and 4 - Chatfield to Colfa~. Develop a prel im1nary design in accordance w1th the Phase A report recommendations. Reach 5 - Colfa~ to Cherry Creek. Develop a prel iminary design in accord. ance with the Pha~l:' A report recomendations; however, in the process, develop possible altern~tives to the use of a collapsible dam at the Farmers and Gardners diversion dam. A collapsible dam could result in costly operation and maintenance cost cormlitments that need to be further clar1fied Md other options evaluated before the preliminary design is complete<J. Reach 6 and 7 -Cherry Creek to Sand Creek. Developaprelim1narydesign in accordance with the Phase A report recommendations. Reach 8 - Sand Creek to Baseline Road. Develop a preliminary design in accordance with the Phase A report recommendations. As part of the pre- li'TIinary design, show the reCOll111ended alignment, profile, cross section South Platte River In this reach. Theprelirninarydesignshallbebasedon the minirnum rnaintenance alignment channel recommendations contained in the 'FirlJl Report, Streilrll Stability Investigation, South Platte River, Chat- field Dam to Baseline Road," November 1983 by M.A. Stevens. In addition to the specific direction given for each reach,more generic reQuirernentswereimposedbythesponsorsonthepreliminarydesign. These 12 items are listed below and supplemented the Qoals and criteri~ presented i~ Sectio~ VI. 1. [nfOfce tile ex ist i ng f1 oodpl ai n regul at ion~ and regul ate the identified 1aa-year floodplain. 1. There is a need for regulating theresidual1QO-year floodplain that remains after the Phase Bplan 1simplemented. Theexisting 1oo-year floodpl ain ha~ to be regul ated until such time it 1s mod- ified by physical changes to the exhting drainaqeway facilities. Planning for or anticipating such changes does Mt justify reguh_ ting anything other than the floodpl ain defined using e~istlnQ channel conditions. 3. Encourage purchase of flood insurance. 4. There must be adequate maintenance access to all reaches of the r 1 ver. Maintenance tra i 1s shaul d have a m 1 niml//Jl f1 ~t surface width of 12 feet and, if paved, the paved portion should co~sist of an R foot wide concrete surface. II s. Adequate erosion control for all chan~el improveme~ts and struc- tures is required. i, 6. All new development i~ the watershed must provide on-site erosion COntrol during construction to 1 imit the d01'Junt of fi~e sil t and topsoil washed into the drainagew<lY dur i~g the more fr~Quentl y occurring runoff events. ,. A recommended general prioritildtlon of improvements is necessary to assist local governments in implementation. 3. Where land adjacent to the river is subject to development or redevelopment, the development and redevelopment should follow master planreCO/lI11endations and be in accordance with floodplain reguldtio~s .