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5.9.4.3 For embankment dams, the following design considerations must be addressed <br />and documented in the Design Report. <br />5.9.4.3.1 Geometric and Design Requirements - Dam geometry shall be supported by <br />the slope stability and seismic analysis, and shall meet the following minimum <br />requirements: <br />5.9.4.3.1.1 The crest width shall be equal to the jurisdictional height of the dam <br />in feet divided by 5, plus 10 feet. The maximum crest width required shall be 25 <br />feet. <br />5.9.4.3.1.2 The crest shall have a camber sufficient to maintain the design <br />freeboard, based on the anticipated magnitude of crest settlement. The anticipated <br />magnitude of crest settlement shall be based on engineering analyses. In no case <br />shall the camber be less than 0.5 feet. <br />5.9.4.3.1.3 Guidelines for minimum dimensions of impervious core zones for <br />zoned embankment dams up to 50 feet high are defined in the "Design of Small <br />Dams," United States Department of the Interior, Bureau of Reclamation, Third <br />Edition, 1987, U.S. Government Printing Office, Washington, D.C., 20402, (later <br />amendments, editions or subsequent publications not included). Zone <br />dimensioning for dams over 50 feet shall be evaluated using industry standard <br />analyses. <br />5.9.4.3.1.4 Roads located on the dam crest shall have appropriate surfacing to <br />provide a stable base that resists rutting and provides adequate traction for safety <br />in wet conditions. <br />5.9.4.3.1.5 The crest design shall include details to protect impervious cores from <br />desiccation or frost penetration, as approved by the State Engineer. <br />5.9.4.3.1.6 The crest shall be provided with adequate cross slopes to the upstream <br />edge to prevent ponding. <br />5.9.4.3.1.7 Minimum dimensions for internal granular filter and drain zones shall <br />meet requirements of Rule 5.9.4.2. <br />5.9.4.3.1.8 The embankment shall be protected against external erosion. <br />5.9.4.3.1.9 The downstream slope of the embankment dams shall be provided <br />with a well maintained vegetative. cover to prevent surface erosion from <br />occurring. No landscaping or planting of trees or large vegetation shall be <br />permitted within 25 feet of the footprint of the dam. <br />5.9.4.3.1.10 The shear strengths of the foundation soils (including suitable factors <br />of safety) shall not be exceeded under any foreseeable loading conditions. <br />28