6.2. SR 06-19-2000 - Laserfiche WebLink

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Ms. McPherson June 14, 2000 Page 2 C. Storm 1. Do Street 1. 2. 3. 4. The minor adjustment to the road alignment has created a Iow spot in the front of Lot 3 Block 3. In order to drain this area, a pipe is shown under the road to the wetland complex in the center of Block 4. An easement will be necessary across Lot 3 Block 4 to accommodate this pipe and the drainage through it. A better solution, we believe, would be to just grade the Iow spot out of Lot 3. It does not appear .that Lot 3 is one of the wooded lots so grading in this area would not disturb existing vegetation. A previous comment letter indicated that Lots 6 and 7, Block 3 had lowest openings below the emergency overflow over Jarvis Street. The house elevations on Lot 6 have been raised to get the lowest opening elevation above one foot above the emergency overflow. However, a similar adjustment has not been made for Lot 7. An emergency overflow elevation needs to be provided for the culvert underneath the road near Lot 5 Block 1. The sedimentation pond located between Lots 2 and 3, Block 4 should have sufficient grading at the outlet to insure that drainage does not cross the house pad on Lot 2 Block 4. Drainage No calculations were included for the sedimentation ponds. These calculations should be included with the next submittal. Normal water elevation at high water elevation for each pond should be noted. Storm drainage calculation should be submitted with the drainage calculations. The colors on the drainage area map denoting the proposed drainage areas and existing areas should be reversed. Areas should be noted for the proposed drainage areas. Verify that the areas shown on the map and areas used in the TR20 program correspond. The 18-inch CMP outlet for Basin 1 should be shown on the plans when the drainage area map is resubmitted with the calculations. For the next submittal, please do not use yellow-colored font and submit a full- size plan. Construction All storm sewer piping should be noted as reinforced concrete pipe (RCP). All rip rap should be Class IV. A detail for the riser control structure should be included in the plans. The placement of the catch basins shown at the intersection of 226th Avenue on Sheet 4 should be revised or an additional catch basin should be added to capture water flowing south on 226th Avenue before the intersection depending on the storm water flows. MH 111 should be placed in the curb line, and an R-3067-V casting should be used. The storm sewer on 226th Circle should be labeled in plan view and shown in profile. Ltr--O61400-McPherson.doc Howard R. Green Company CONSULTING ENGINEERS