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<br />Page 41 <br /> <br />2. Runoff (developed) <br />a. Off-site + site for as many design points as required <br />1. Separate time of concentration (Tc) for each design <br />point (Rational Method) <br />2. Runoff coeff. or permeability coeff. from Table III <br />3. Existing drainage facilities carrying flows - must <br />include flow for entire tributary area for each <br />design point <br />4. Irrigation ditch flows <br /> <br />3. Detention <br />a. Storage VolUJDes - 5 year and 100 year; Release Rates - <br />5-year and 100-year. <br />*b. Pond Outlet - Control Structures <br />1. Outlet control structure type <br />2. Use appropriate outlet discharge calculatlons <br />Include offsite flows <br />3. Consider head at entrance <br />4. Provide excess capacity for grates <br />5. Use restricter plate to reduce inlet area when neces- <br />sary <br />6. Compute outlet velocity and provide energy dissipator <br />if velocity exceeds maximum permissable channel <br />velocity <br />7. Check excess storm water passage effects <br /> <br />*c. Size outlet structures for parking areas <br /> <br />*d. Depths of ponding in parking areas, durations of storage <br />for each storm <br /> <br />*4. Streets <br />a. Compute depths and velocity of flow, for initial & major <br />storm unless flow is less than that allowed by Figure 12. <br />b. Inlet capaci ties and depths at inlet. <br />c. Meet street standards in Table VII. <br /> <br />c. <br />d. <br /> <br />Channel Flow <br />Roughness coefficient <br />Trickle channel <br />Depth and velocity for initial and major storms <br />Channel protection <br />Minimum freeboard <br />Hydraulic grade line <br /> <br />*5. <br /> <br />Open <br />a. <br />b. <br /> <br />e. <br /> <br />g. <br /> <br />*6. Hydraulic Structures - pipes, culverts, inlets, etc. <br />a. Culvert capacity using standard nomographs (Fig 7 to ll) <br />b. Storm sewer capacity at each design section <br />c. Inlet capacity <br />d. Flow depth or headwater depth at inlet <br />e. Drops <br />f. Weirs <br />g. Streets, gutters, and crosspans <br />