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<br />Mr. Dan Hernandez <br />September 25, 1989 <br />Paqe Two <br /> <br />1. A qualified drainage engineer should review the surface drainage within <br />the original permit area and the access road and provide the <br />appropriate designs to prevent erosion, sedimentation, and downstream <br />damage caused by flowrates off of the affected lands of the permitted <br />site. Specifically, along the access road the design should include <br />enough trench grates, culverts, water retention ponds, etc., to <br />replicate as closely as possible the natural drainage pattern. fhe <br />design would also need to incorporate the affects of berms, barriers, <br />curbs, or guardrail restraint as part of a total roadway design. <br />2. If berms are used for vehicular restraint, they should be compos~:d of <br />non-eroding, non-sediment producing material. The berms should Ise <br />placed far enough from the shoulder that they are not pushed or ~:roded <br />down the hillside. A berm type of restraint should only be used where a <br />geotechnical engineer indicates the slope stable enough to support the <br />added surcharge loading. Where berms can not be used the guardrail <br />concept should be implemented to comply with.MSIIA regulations. <br />3. Dosed upon current submittals by the operator's consultants, I w~~uld <br />leave the following questions and comments: <br />a. Where will the unstable fill materials and sludge from the <br />obstructed drainage channel be moved to? <br />b. In what manner will ttie silt-laden water be removed from the pond? <br />To allow the operator to pump or drain the water across private <br />property may be a liability. <br />c. The amount of sedimentation in the stream bed indicates a net;d for <br />a permanent, approved sedimentation pond within the phase I .area. <br />Also past correspondence speaks to this need, reference January <br />15, 1985, letter form Merk Ileifner to Philip Saletta, item 2, <br />which, describes gullying and erosion as a result of storms. The <br />sedimentation pond is discussed as a recommendation item on Faye two <br />of that letter, which is a reply to the corresponding inspecl:ien <br />report. The permanent sedimentation pond should be built <br />prior to the removal of the stream blockage. This would prevent <br />operating without this item during the remedial work. <br />