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year peak flows in accordance with the WSDOT Hydraulics Manual. Conveyance design <br />calculations shall be included in the Drainage Report required as a part of Core Element #1. <br />Stormwater conveyance systems consisting of catch basins and storm drain pipe are required for <br />roadways with curbs and gutters or thickened asphalt edges. Stormwater conveyance systems shall <br />be designed and constructed in accordance with the WSDOT Hydraulics Manual, all applicable <br />WSDOT Standard Plans, and the WSDOT Standard Specifications. See Section KCC 12.04.05.080 for <br />additional requirements for culverts. <br />12.04.05.070 Stormwater Site Plan Submittal Requirements for Subdivisions. <br />Submittal Requirements for Stormwater Site Plans (Reference Ch.3 of the SWMMEW) shall be as follows for <br />subdivision projects: <br />4. Preliminary Submittal Requirements <br />Collect and Analyze Information on Existing Conditions <br />a. Downstream Analysis <br />b. Identify areas of high erosion and sediment depositions <br />c. Locations of sensitive and critical areas <br />2. Determine Applicable Core Elements <br />3. Prepare a Conceptual Stormwater Control Plan <br />a. Identify Stormwater Conveyance System <br />b. Identify Stormwater Detention/Retention Area & Methods <br />5. Final Submittal Requirements <br />1. Apply preliminary subdivision conditions relating to stormwater <br />2. Prepare a Final Stormwater Control Plan <br />3. Provide a Drainage Report with supporting calculations <br />4. Prepare a Construction Stormwater Pollution Prevention Plan <br />6. Provide a copy of recorded Notice to Title — For maintaining private stormwater drainage <br />system prior to final project approval. The Notice to Title is available at the Public Works <br />Department. <br />12.04.05.080 Culverts. <br />Culverts with a minimum diameter of 18 inches and beveled ends with a 4:1 slope shall be installed at all <br />County road intersections, at all crossings of natural drainage courses, and at all locations where the <br />finished grade of the proposed roadway prism creates a collection point for stormwater. Culvert material <br />shall be as follows: <br />A. In fire prone areas, all culvert material shall be galvanized corrugated metal. <br />Title 12 Kittitas County Code I Draft No. 5 — Working Draft forAdoption 6/12/2018 <br />49 <br />