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Part II.C.2.b.i.2. documentation which demonstrates that all options were considered and for each option explains why it is considered infeasible. In no case shall the runoff reduction achieved from the newly constructed impervious areas be less than the Minimum RRv as calculated using the criteria in Section 4.5 of the DM. The remaining portion of the total WQv that cannot be reduced must be treated by application of standard SMPs. ii. Channel Protection Volume (CPv): Provide 24 hour extended detention of the post-developed 1-year, 24-hour storm event, remaining after runoff reduction. Where a CPv control orifice is provided, the minimum orifice size must be 3 inches, with acceptable external trash rack or orifice protection. The CPv requirement does not apply when: 1. Reduction of the entire CPv is achieved by application of runoff reduction techniques or infiltration systems; or 2. The 1-year post-development peak discharge is less than or equal to 2.0 cfs; or 3. The site directly discharges to tidal waters, or a fifth order or larger water body (stream, river, or lake) where the increase in smaller flows will not impact the stream bank or channel integrity. However, the point of discharge must be adequately protected against scour and erosion by the increased peak discharge. iii. Overbank Flood Control Criteria (Qp): Requires storage to attenuate the post-development 10-year, 24-hour peak discharge rate (Qp) to predevelopment rates. The Qp requirement does not apply when: 1. the site directly discharges to tidal waters or fifth order or larger streams; or 2. A downstream analysis reveals that overbank control is not required. 26 Page 732 of 849