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do <br /> <br />no objectionable secondary consequences. The NCSCC recognizes that <br />the management of Storm Water Runoff to minimize or control <br />downstream channel and bank Erosion is a developing technology. <br />Innovative techniques and ideas will be considered and may be used when <br />shown to have the potential to produce successful results. Some <br />alternatives are to: <br /> <br />Avoid increases in surface runoff volume and Velocity by including <br />measures to promote infiltration to compensate for increased runoff <br />from areas rendered impervious. <br /> <br />Avoid increases in Storm Water Runoff discharge Velocities by <br />using vegetated or roughened swells and waterways in lieu of <br />closed drains and high velocity paved sections. <br /> <br />° <br /> <br />Provide Energy Dissipaters at outlets of Storm Drainage Facilities <br />to reduce flow Velocities to the point of discharge. These may <br />range from simple rip-rapped sections to complex structures. <br /> <br />o <br /> <br />Protect watercourses subject to Accelerated Erosion by improving <br />cross sections and/or providing Erosion-resistant lining. <br /> <br />Exceptions - This rule shall not apply where it can be demonstrated that <br />storm water discharge Velocities will not create an Erosion problem in the <br />receiving watercourse. <br /> <br />The following is a table for maximum permissible Velocity for Storm <br />Water discharges: <br /> <br />Maximum Permissible Velocities <br /> <br />Material <br /> <br />Feet/ Meters/ <br />Second Second <br /> <br />Fine sand (noncolloidal) <br />Sandy loam (noncolloidal) <br />Silt loam (noncolloidal) <br />Ordinary firm loam <br />Fine gravel <br />Stiff clay (very colloidal) <br /> <br />2.5 O.8 <br />2.5 0.8 <br />3.0 O.9 <br />3.5 1.1 <br />5.0 1.5 <br />5.0 1.5 <br /> <br />12 <br /> <br /> <br />