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Page 5of10 <br />permanent? <br />g. On page 2.05 -19 the phrase "west DWDA" is used several times. To avoid ambiguity it <br />would be preferable to refer to development waste piles as: DWDA 1, or DWP, (the <br />reclaimed development waste pile); DWDA2 (the newer development waste pile <br />immediately to the east of DWDA 1); and DWDA3 (the approved, but not as yet <br />bonded or constructed, development waste pile at the west end of the site. Currently <br />some development waste is stored in the soil storage area — this was approved as a <br />temporary measure only, therefore the Division's preference is that this area is referred <br />to explicitly as the "temporary DWDA ". These comments also apply to page 2.05 -46. <br />h. On page 2.05 -20 there is confusion regarding the description of surface water routing. <br />Ditch D-32 is erroneously described as part of the storm water system. In the passage <br />below, D -32 has been missed out between culvert C -13 and pond 007. <br />I. On page 2.05 -21 the passage beginning "An erosion estimate..." appears to be out of <br />logical place. The culvert should be identified by number (presumably C -13) to avoid <br />ambiguity. Presumably "invert" should be "inlet ". <br />J. The passage beginning "Culverts C -21 through C-25... " needs to be revised. Based on <br />the location of C -21, it presumably refers to the west portal fan and substation. C -25 is <br />not identified on the currently approved version of Map -14. <br />k. On pages 2.05 -21 and 2.05 -22, a passage was appended to the paragraph discussing <br />pond 4, seeking to make the pond a permanent impoundment. The Division <br />acknowledges the comments of Colorado Division of Parks and Wildlife, in <br />informational exhibit A. Rule 4.05.9(13) sets out six criteria that must be met before an <br />impoundment may be approved as permanent. Underlying those criteria is the <br />expectation that the permanent impoundment actually impounds water. In the case of <br />pond 4 that is not really the case; even in the unusually wet summer of 2013 the level <br />of water in the pond never exceeded a puddle in one comer. The Division suggests that <br />it would be appropriate to remove the embankment containing the spillways, restoring <br />the approximate original contour and unimpeded access to the river. <br />1. On page 2.05-22, in the paragraph beginning "Exhibit 19..." there are multiple <br />typographical errors, and multiple versions of the "acre- foot" unit. For brevity the <br />paragraph is copied below, with errors and inconsistencies highlighted: <br />Exhibit 19- Sediment Design Specifications and West Portal Drainage Plan, confirm <br />that Pond 007 (as- built) has sufficient storage capacity to contain 10 year 24 hour storm <br />even runoff fi om pond 006 and 007 drainage areas a total of 6.6 acre feet. In addition <br />the Universal Soil Loss equation was used to estimate sediment yield from these areas at <br />0.3 acre -Ft lyr. (0.9 acre feet for three years) at a conservative 1.0 sediment delivery <br />ratio The total required capacity for Pond 7 is therefore 7.5 acre feet. Construction of <br />the Bates Portal will add in incremental amount of water (0.21 A -F) and sediment (0.01 <br />A -F) to pond 7. Therefore the required storage volume for sediment pond 007 is 7.7 acre - <br />ft. As shown by the stage volume curve for Pond 007, 9.2 acre ft. of storage is available <br />in Pond 007. The emergency spillway is adequate for passing peak 25-year 24 -hour <br />flows from both drainage areas while maintaining 1 foot freeboard. <br />m. On page 2.05 -23 there are several typographical errors and inconsistencies: <br />