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<br />., <br />1. The location of the SDH#4 process pond is not shown on Map 138. Please add the <br />pond to the map. <br />2. From the drawing entitled "SDH #4 Discharge Layout", we are unable to determine <br />the size of the watershed from which runoff will be diverted through the use of "V" <br />ditches in the vicinity of the drill pad and process pond: The scale of Map 138 is too <br />small to accurately determine the drainage area. Please revise the SDH#4 discharge <br />layout drawing so that it shows the entire watershed and includes any structures which <br />may affect the volume of runoff. <br />3. The work sheets entitled "'V' Ditch Design Detail and Calculations" include a value for <br />Manning's "n" of .3, based on some grass or weed protection. We believe a value of <br />.045 may be more appropriate since at the time of initial construction, there will likely <br />be no vegetation in the channel. <br />4. The design calculations for the "V" ditch do not appear to include the freeboard <br />(minimum .3 feet) required by Rule 4.05.3(7)(b). Please revise the calculations as <br />necessary to include the required freeboard. <br />5. We did not receive drawings which depict the embankment of the SDH#4 process <br />pond, and so were unable to determine what type of dischazge structures are proposed. <br />Please submit a drawing which shows the location, elevation, and characteristics ofboth <br />the primary and secondary spillways. <br />6. With the information given, we are unable to determine the volume of the SDH#4 <br />process pond. Please submit a drawing or narrative which would enable us to <br />determine its capacity. A detailed topographic map would be ideal. <br />7. The process pond must be constructed under the supervision of and construction <br />certified by a registered professional engineer, as required by Rules 4.05.9(2) and <br />4.05.6(10). WFU should include such a commitment on Page IV-54A, or other <br />appropriate location as they see fit. <br />8. From the SDH#4 discharge layout drawing, we are unable to determine how discharge <br />will be conveyed from SDH#4 to the process pond. Please provide that information. <br />9. The design calculations for the culvert in the dry wash indicate that the area of the <br />watershed draining to the culvert is 58 acres. Examination of Map 138 indicates that <br />the watershed is at least 80 acres, with an additional unknown area off the eastern <br />border of the map. Please provide us with a detailed topographic map which shows the <br />entire watershed draining to the culvert. Please also include any structures <br />(impoundments, culverts, etc.) which would affect the amount of flow into the culvert. <br />Janet Binns <br />2 <br />February 24, 1993 <br />