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Page 2 of 4 <br />Diversion Ditch. The design information for these culverts, located in Exhibit 19(19) <br />indicates that the drainage area is 25.9 acres and the runoff is 51.82 cfs (again, this <br />would be modeled on the 100y /24hr event); <br />Exhibit 20 includes a discussion of the RDA "contour ditch" designs. Table 9 of the <br />exhibit provides ditch details. In Table 9, the minimum contour ditch depth for a 50 cfs <br />flow, allowing for 1.0' of freeboard is 3.5'. The ditches will be triangular in shape and <br />will not require rip rap; <br />The overall gradient of the segment is approximately 2 %, draining to the east. <br />It appears that at one time there was an approved design specific to the RDA Clean Water <br />Diversion Ditch, but that it may have been inadvertently removed. <br />Please either identify the location in the permit application package of the approved <br />design for the RDA Clean Water Diversion Ditch, or provide a new design for the ditch. <br />If NECC is unable to locate the design, a new design could be based on the existing design <br />information for Culverts C75 and C76 (currently approved pages 24 -26 of Exhibit <br />19(24)). NECC would need only to submit a proposed channel design (such as a SEDCAD <br />channel utility output) for inclusion in Exhibit 19. <br />Notice of Violation CV- 2013 -009 was issued for "failure to construct and maintain the RDA <br />upland diversion ditch in compliance with the approved design ". The abatement of the <br />violation required construction of the ditch so that it is in compliance with the approved design. <br />In response, NECC has: <br />• Proposed to revise the permit to remove the specifications for Ditch D -55 (page 2.05- <br />I la); <br />• Provided a typical cross section for the constructed ditch (shown on the RDA -Ditch <br />Profile drawing), and; <br />Provided plan and profile information on Ditch D -55 and the RDA Clean Water <br />Diversion Ditch. <br />NECC has not adequately addressed the requirement to construct the RDA upland diversion <br />ditch as designed. <br />a. Please provide surveyed ditch cross - sections, for the entire constructed RDA <br />upland diversion ditch (i.e. both segments) to indicate that the ditch has been <br />constructed as designed. <br />b. Please restore the previously approved page 20.5 -11a that lists the design <br />information for Ditch D -55. <br />The as —built locations of ditches D -55 and the RDA Clean Water Diversion Ditch on the "RDA <br />Ditch D55 Plan" drawing are consistent with the approved design. The title of this drawing, <br />however, is somewhat misleading. <br />Please revise the title of the drawing to clarify that two ditches, Ditch D -55 and the RDA <br />Clean Water Diversion Ditch, are depicted. (You may choose to redesignate what I have <br />been referring to as the "RDA Clean Water Diversion Ditch ") <br />4. The "RDA — Ditch Profile" drawing includes a light weight dashed line (most evident between <br />stations 27 +00 and 29 +00) that is not identified on the drawing. <br />Please revise the drawing to include a legend that identifies all lines and symbols used, <br />and revise the title consistent with Item 3, above. <br />5. After reviewing the October 8, 2013 as -built information for the RDA upland diversion ditch, <br />