Laserfiche WebLink
Page 5 of 5 <br />56. Under Rule 2.05.3(4), in the Sedcad designs for the west culverts, a curve number of zero <br />is used for the irrigated wetlands area, citing a ground cover of 100% as justification for <br />that curve number. If the wetlands are saturated or are comprised of standing water, a <br />precipitation event could produce runoff in spite of the vegetative cover. Please describe <br />the nature of the wetlands as it relates to the determination of the curve number. <br />In the submittal dated April 11, 2011, CAM had revised the curve number of the <br />wetlands to 74. However, the April 11, 2011 submittal had left out certain Sedcad design <br />pages for the culverts. In the submittal dated July 8, 2011, the Sedcad design pages <br />showing peak flows were provided. As far as the design pages showing the sizing of the <br />culverts, CAM elected to depend on a reference on page Exh 9 -2 to Figure 4 -18 of the <br />Handbook of Steel Drainage and Highway Construction Products. Since that reference <br />book may not be readily available to others, the Division requests that one generic copy <br />of Figure 4 -18 be included with the culvert designs. <br />58A. On revised page 2.05 -19 of the April 11, 2011 submittal, there is a statement that the <br />ponds will be cleaned out no later than when the ponds are 75% full of sediment. Please <br />revise this sentence to read that the ponds will be cleaned out when the sediment level <br />reaches no more than 75% of the designed sediment capacity. <br />The Division has no further concerns. The requested change was made on page 2.05 -20 <br />of the July 8, 2011 submittal. <br />97. In Table 2 — Surface Water, on page 2.05 -57 of Section 2.05.6(3)(b)(iv), CAM lists that <br />chromium (Cr) will be analyzed. CDPHE receiving stream standards require the analysis <br />of both chromium III (Cr +3 ) and chromium VI (Cr +6 ). Please include both chromium III <br />(Cr +3 ) and chromium VI (Cr +6 ) in Table 2. <br />The Division has no further concerns. CAM has elected to not change Table 2, citing the <br />Division's regulations concerning baseline water quality data. <br />98. Please add total hardness, flow, lab ph and lab conductivity to the list of surface water <br />sampling parameters in Table 2 on permit text page 2.05 -57 of Section 2.05.6(3)(b)(iv). <br />The Division has no further concerns. Table 2 on revised permit text page 2.05 -61 was <br />amended to include total hardness and flow. However, lab ph and lab conductivity were <br />not added by CAM to the table, citing the Division's regulations concerning baseline <br />water quality data. <br />c: /word2007 /fruita/newappmemo3 <br />