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"...the CN approach is a runoff approach and not an infiltration approach. Certainly infiltration is a factor, but so is quick return flow and initial abstractions. Combining the CN approach with infiltration approaches such as minimum retention rates carries the CN concept beyond it(s) original intent and beyond the data on which CN's are based." p.83, B,W&H. In conclusion, this argument is not hydrologically valid for two reasons. The precipitation in the previous five days reflected average rainfall reflective of a Type II antecedent moisture condition. The method may be an inappropriate marriage of theory and empirically derived data. Quick return flows representative of our daily up slope thunderstorms are accommodated by the CN approach which is based on data acquired on studies from all over the United States. III. The peak flow from a 10-year 24-hour storm in the drainage basin at issue is 49 cfs using an antecedent moisture condition of II. The design in the permit application for this drainage showed a peak flow of 98 cfs. Joe Dudash replicated Mr. Lewicki's results on STORM and found that he could generate dramatically different peak flows based on the unit hydrograph type. Peak Flow Forested 49.3 Agriculture 84.5 Disturbed 101.0 Various hydology computer models utilize a parameter such as this to reflect fast, medium or slow runoff. Forested or brushy vegetation tends to slow the runoff down and retain more of the rainfall. This drainage basin is composed predominantly of reclaimed grassland which would suggest that the agriculture unit hydrograph should have been used. IV. Any flow which is greater than the peak flow from a 10-year 24-hour event should be exempted from the performance standards. I would accept this argument, but I would point out that ditches are required to have freeboard and to accommodate poor installation, deposition or a storm slightly larger than a 10-year 24-hour event. Y. Photographic documentation supports a flow of 56 cfs. I would accept this flow estimate, but I would point out that an 10-year 24-hour flow at this site is approximately 90 cfs. VI. Landowner intervention has resulted in additional disturbance at the site for which the operator should not be accountable. Rule 2.03.6 requires operators to maintain right-of-entry through the bond liability period and to have the consent of the landowner. 5347E/scg