10-10-2016 Council Packet - Laserfiche WebLink

Home Browse Search

Final Plat Application 16-3867 Tanager Estates Page 4 4.5. Grading for the outlet of Infiltration Basin -1 should be revised to indicate a weir, as defined on the Final Details Plan. 4.6. Grading for the outlet of the.Pond should be revised to incucate a pipe from the outlet control structure into the pond. 4.7. A berm should be provided around the Pond and Infiltration Basin -1, with the top of berm a minimum I' above the adjacent 100 year high water level. The emergency overflow for the Pond should be placed at the Pond's 100 year HWL (938.6) and be a minimum 10' wide. The access berm between the Pond and Infiltration Basin -1 should be a minimum 8' wide to allow for maintenance of the outlet control structure and emergency overflow. 4.8. Double siltfence must be provided for any work indicated within 50' of a wetland. 4.9. Erosion control blanket should be indicated on all slopes of 3:1 to be installed in conjunction with final stabilization. 4.10. Erosion control blanket should be provide between the curb cut on Lot 2's driveway and Rain Garden - 2 to minimize potential for erosion. Final Wetland Buffer Monument Pian 5.1. Tree Preservation Monuments, as required by the Preliminary Plat Approval resolution, should be included on the Monument Plan Final Details Plan 6.1. The outlet for Infiltration Basin -1 is indicated to be a 0.5' weir. A detail should be provided for the weir in order to verify adequate design. Due to the small opening, a poured concrete weir tied back into the earth bank on each side is recommended. The bottom of the weir should be placed at the starting water level indicated in the calculations (936.0). A 10' wide tier should be provided at the 100 year high water level (938.1) to provide an emergency overflow for extreme events. The top of the weir should be placed 1' above the 100 year HWL (939.1) to match the top of the berm. 6.2. The detail for the Standard Skimmer Structure (STO-8A) should be revised as follows: a. The Skimmer Opening should be replaced with a pipe flowing from the structure to the pond. Back slope on the pipe will allow for flushing during future pond maintenance. b. The sump should be removed from the structure, and the inlet pipe should be placed directly at the bottom. A sump in this location would be difficult to maintain. c. The lower rim of the structure should be placed at the 100 year high water level. 6.3. Notes should be added to the Infiltration Rain Garden Detail to provide direction regarding sequencing and construction. Infiltration areas should be constructed after all upstream areas are permanently stabilized. Construction should be performed by low impact equipment to minimize compaction. Please let me know if you have any questions or need additional information. Sincerely, BOLTON & MENK, INC. ,Qg 6-4 Robert E. Bean, Jr., P.E. Water Resources Engineer