04-22-2019 Council Packet - Laserfiche WebLink

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4. The applicant shall label storm structures. Storm structures are labeled on the final plans and noted on the grading. 5. The applicant shall provide explanation as to why they HydroCAD model includes “Pond 400” which is not shown on the drainage map. The location shall be confirmed within the drainage maps if applicable. Pond 400 is the downstream pond in Northpointe Development and was added for the tailwater conditions of the pond. 6. The applicant shall povide 2.0 feet of freeboard from the 100-yr HWL existing adjacent walk out property low entry elevations. The HWL elevation of the pond is 917.4 which is a 1 foot freeboard. At the time the existing houses were constructed the pond was modeled pre Atlas 14. This was approved with the Northpointe PUD. Eastside villas lowers the 100-YR HWL from 917.5 to 917.4 (Atlas 14). 7. The applicant shall provide catch basin spacing calculations, and include structure size information on the utility sheets Spread calcs have been submitted. As discussed with Diane, double catch basin will not be needed at the center low point. Structure size is shown on the storm sewer schedule on the plans. 8. The applicant shall indicate in Table 2 of the SWMP what HydroCAD nodes are associated with each row, and verify all inputs in the table are correct. S-NW is the subcatchment discharging northwest for proposed and existing conditions. Pond 500 is the discharge to the south for proposed and existing conditions. Reach 5R is the discharge to the northeast for proposed and existing conditions. SWMP updated. 9. The applicant shall Provide a detailed explanation in the SWMP describing why volume reduction requirements are not being met. Refencing other developments is not adequate explanation for rule variances. a Use the RCWD “Required Water Quality Treatment Volume (ft3)” equation to quantify the required water quality volume Section 2.5 of the SWMP discusses the clayey and silty soils located onsite. Northpoint referenced as the borings were similar and the sites are adjacent to each other. • Water Supply 8- inch watermain would be extended from an existing stub on Dogwood Street with 1-inch Type K copper services extended to each lot. A temporary hydrant would be installed on the northwest stub street for future looping and expansion on Butternut Street. Comments: 1. The applicant shall show the locations of water services with final construction plans. Services are shown on final plans. 2. The applicant shall provide pipe profiles with final construction plans. Pipe profiles are shown on the final plans. 3. The applicant shall show a minimum of 10’ of separation between water main and sanitary sewer (except for services). This is shown on the plans (note near STA. 4+00) 4. The applicant shall specify that ductile iron pipe (DIP) water main shall be encased in polyethylene wrap. Note added to plans. 5. The applicant shall label the bend at Sta. 8+75, adjacent to MH 3. As discussed, GV moved to the bend location. (pipe deflection is only 4° so bend not necessary) 6. The applicant shall include road stationing in the profile view of the proposed utilities. As discussed, the pipe alignment doesn’t follow the centerline alignment. MH centerline station denoted in the profile view. • Sanitary Sewer 8- inch Polyvinyl Chloride (PVC) Pipe would be extended from existing stub on Dogwood Street with 4-inch Schedule 40 PVC services extended to each lot. The development proposes ending with a stub for future extension and service of Butternut Street. Comments: 1. The applicant shall show the locations of sanitary services with final construction plans. Services are shown on final plans. 2. The applicant shall provide pipe profiles with final construction plans. Pipe profiles are shown on the final plans. 3. The applicant should adjust sanitary sewer main and services to avoid services that are longer than 100 feet in length. If any services are required to be greater than 100 feet, then the applicant shall add a note that clean outs are required on all sanitary services that are longer than 100 feet in