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<br />e <br /> <br />e <br /> <br />5.1 CONSTRUCTION PLAN REQUIREMENTS <br /> <br />5.2.1 A drainage map shall be included in the construction plans. The drainage area map shall <br />include: <br /> <br />A. Drainage areas, including areas draining from off-site onto or adjoining the project. <br /> <br />B. Design storm runoff, based on the type of facility and storm frequency listed in Section <br />5.4. <br /> <br />C. 100 - year runoff <br /> <br />D. Route of overland flow including the overflow to a drainage channel or detention <br />facility. <br /> <br />E. Water surface profiles for the 25-year and/or 100-year storms in the outfall channel. All <br />available information will be considered when making this determination. <br /> <br />F. Flow per inlet. <br /> <br />G. Maximum ponding elevation <br /> <br />5.2.2 Detailed drainage calculations shall be submitted with the construction plans. <br /> <br />5.2.3 A lot grading plan should demonstrate that the finished grading plan will drain to approved <br />collection and discharge points and that the overland flow of water from adjacent properties <br />will not be impeded. <br /> <br />5.2.4 The hydraulic gradient for the design storm may be shown on the construction drawings. <br />Calculations for the elevation of the hydraulic gradient shall be provided with the design storm <br />drainage calculations. The hydraulic gradient must be below the gutter line for the design <br />storm. The tailwater elevations based on a 25-year frequency in the outfall channel shall be <br />used for calculations of the hydraulic gradient <br /> <br />5.3 USE OF PREVIOUSLY DESIGNED AND INSTALLED INFRASTRUCTURE <br /> <br />Situations where previously installed infrastructure is in place but not yet utilized to its design <br />capacity will be considered on a case by case basis. The developers engineer shall after <br />consultation with the City, prepare a report that: <br /> <br />a. outline the original design criteria. <br /> <br />b. evaluates the impact of the original design on the receiving stream, adjoining <br />properties and/or the 100 year Floodplain. <br /> <br />Based on the report, the City Engineer may allow full or partial use of the previously installed <br />infrastructure and may require it to be supplemented with detention or other facilities. <br /> <br />Stormwater Criteria 2 of 12 <br />