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2 <br /> <br />New Horizon Technical Revision TR80 Prepared by: R. Reilley <br />Date: September 2017 <br /> <br />New Horizon TR 80 Permanent Culverts <br /> <br />Rules 4.03.1 and 4.03.2 Culverts <br /> <br />The following questions relate to permanent culverts C134 and C137 in the New Horizon Permit <br />from DRMS review of the TR80 submittal: <br /> <br />September 2016 <br />Table 2.05.3.(3)-3 Permit Area Culvert Designs, C130 – C181 pg. 33 and associated SedCad Modeling <br /> <br />For C134, table 2.05.3 calls out 2 each 18 in pipes. However SedCad modeling submitted for this <br />culvert outputs a result of one 18 inch pipe. Also, the submitted modeling appears to have utilized <br />the design flow of 10.6 rather than the peak flow of 21.3 for culvert sizing. <br />1. Given that the design event is a 100 yr-24hr event as required by County road designs <br />please either, explain your rationale for using the lower design event, or submit modeling <br />utilizing the peak flow value for this culvert. <br /> <br />For C136, table 2.05.3 the submitted modeling appears to have utilized the design flow of 4.9 rather <br />than the peak flow of 14.7 for culvert sizing. <br />2. Given that the design event is a 100 yr-24hr event as required by County road designs please <br />either, explain your rationale for using the lower design event, or submit modeling utilizing the <br />peak flow value for this culvert. <br /> <br /> <br />Table 2.05.3.(3)-3 Permit Area Culvert Desig11s, CJ30-C181 & Associated Revised Pages 35-38 <br /> <br />Average Land Slope is characterized for each of the culverts C134-137. <br /> <br />I. Please clarify, for each of the above mentioned culverts, what slope that culvert lies at <br />and include that information in the culvert descriptions. <br />Response: SEDCAD culvert designs have been included in Attachment 2.05.3(3)-1 <br />for culverts C134-Cl37, which include the slope of the culvert. <br />DRMS SEPT 2017 <br /> Adequately addressed in submitted pages. <br /> <br />2. Please also include tai/water and maximum headwater (ft.) for Culverts 134-13 7. <br />Response: Tailwater and headwater information is included on the SEDCAD <br />culvert designs, which have been included in Attachment 2.05.3(3)-1 for culverts Cl34- <br />Cl37. <br />DRMS SEPT 2017 <br /> Adequately addressed in submitted pages. <br /> <br />3. Please explain how maximum headwater elevation is arrived at. <br />Response: The maximum headwater value for culverts C134-137 is the minimum depth for <br />which the SEDCAD culvert design calculates a minimum pipe diameter of 18 inches. <br />DRMS SEPT 2017 <br /> Adequately addressed in submitted pages. <br />