2013-10-07_REVISION - C1996083 (2)

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Susan Burgmaier -2- October 3, 2013 the third paragraph of page 10 must be omitted or revised to make clear that regard less of weather conditions, the maximum sediment and water levels will not be exceeded at any time. 80 W2; Please see revised pages 10 and 11. 11. DRMS: The copy of page App. B -17 that BRL submitted does not reflect a curve number of 90 for Ditch 5 (Structure 8) as indicated by BRL, and is inconsistent with the runoff volume and peak discharge shown on page App. B -36 and other pages of the design information. Please provide a revised Page App. 617 using a curve number of 90 for the Ditch 5 subwatershed. When the curve number is revised, other portions of the design will be affected (this change appears to have been carried through on the 100 yr run only). Please also revise page App B -6 through 5-9 (Pond sizing, sediment storage, and discharge structure sizing), B -13 (Sedcad structure summary for the 10 yr — 24 hr event), B -18 - 0-19 (complete subwatershed hydrology detail for the 10 yr — 24 hr event), B -23 (structure summary for the 25 yr - 24 hr event), and B -26 through B -29 (Sedcad outputs for the 100 yr — 24 hr event). BOW2: The correct flow for Ditch 5, since it is designed for the 100 -year event, is shown on page B-27 (100 -year SWS Summary). Please see revised pages B-13, 17- 21(10 -year Structure Summary and SWS were updated to reflect curve number revision of Structure 8). Please see revised page B-23 ( SedCad Structure Summary for 25 -year event). Please see revised pages B -6 through B-10 (Pond sizing, sediment storage and discharge structure sizing). Please note, on page B-6, the sediment storage went down as an error in the spreadsheet was discovered. Previously, 8 years was used to cdculate the required sediment storage volume. The volume was revised down toreflect a 3 -year sediment storage volume This change in required sediment storage is updated on Figure 3. Pages App. B-26 to B-29 (SWS Detail for 100 -year event) were revised and submitted as part of the first adequacy response. 13. DRMS: After review of the structure summary, it is apparent that the following structures will need to be redesigned to reflect the peak discharge values on revised page App. B -26: Ditch F4 (peak flow from page App. B -26 is 38.17 cfs, design is based on 37.75 cfs), Ditch F -7 (peak is 37.95 cfs, design is 37.43 cfs), Ditch F -7a (peak is 37.95 cfs, design is 37,43 cfs), Ditch F 14 (peak is 11.73 cfs, design is 11.22 cfs), and Culvert F2 (peak is 34.01 cfs, design is 33.50 cfs), Please also update page App. B -2 with the appropriate Peak Flow values from the Structure Summary table on page App, B -26 for structures Ditch F -4, Ditch F7, Ditch Fla, Ditch F14, and Culvert F2. 80 W2: The Ditch Summary page has been updated, please see revised page App. B-2. Please see revised pages App. B-35, 38, 39, 46, 47 & 62. 14. DRMS: BRL has provided the structure detail, as requested, but we are unable to verify the design discharge value of 4.44 cfs. The structure detail printout provided indicates that the West Diversion Ditch #1 is Structure #2 in the Sedcad run, but the Structure Networking table on page App. B -14 shows that Structure #2 is Pond F. The file name at the bottom of page App. B -58 indicates that this structure detail is part of a different design, and