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Calculate Composite Curve Number With An Unconnected Impervious Area And Total Impervious Area of less than 30%:
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*Referencing TR-55, Appendix F, this calculation is to be used for calculating the composite CN for area with an unconnected impervious area and a total impervious area of less than 30%. |
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Calculation: |
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Designer/Checker: |
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Input: |
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Pervious runoff curve number (CNp) |
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Percent imperviousness (Pimp - %) |
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Ratio of unconnected impervious area to total impervious area, (R) |
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Output: |
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Composite runoff curve number, CNc = |
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