07/13/2016 P&Z Packet - Laserfiche WebLink

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Ms. Katie Larsen July 7, 2016 Page 2 3. A note needs to be added detailing precautions to be taken around infiltration basin during construction to prevent machinery from damaging the basin. 4. The applicant is to label the FEMA floodplain 2015 DFIRM limits on grading plans. 5. The applicant shall review FES 104 and determine if it can be raised to save the existing tree line. The adjacent rear yard high points could be moved into the mid lots. The FES could be a CB. 6. The applicant is to label proposed high points between lots, and proposed elevations at property corners. 7. The applicant shall address the EOF elevations of the ponding areas verses the top of berm elevations. 8. Show EOF extents on plans. 9. There are areas within the site that will require 4 — 6.5 feet of soil replacement to support the proposed infrastructure and buildings. This will be reviewed during construction of the infrastructure and per specifications replaced. The City's Building Inspector shall ensure the buildings are addressed through the building permit. 10. Drainage narrative states there will be no wetland impacts from the proposed project; however the plans show a delineated wetland "Area A" on Enid Trail and Block 1 Lot 11. Please resolve. STORMWATER MANAGEMENT We reviewed the Site Drainage Narrative and Stormwater Calculations for St. Clair Estates, dated May 9, 2016, and revised June 24, 2016, provided by Plowe Engineering, Inc. and have the following comments: No drainage area map provided. Time of concentration for Subcatchment 1 seems high for developed conditions, please verify. 2. Missing result Tables 1 through 4 (rate control results and wetland bounce results). 3. Site Drainage Narrative indicates an increase in 2-year runoff rates to Rice Lake, but HydroCAD indicates runoff rate control is being met in aggregate from the site. 4. Emergency overflow not modeled for Ponds 1, 2, or 3, even though the high water elevations are at, or exceeding, the EOF elevation. Please update HydroCAD to include EOFs and provide scour protection on downstream side of EOF to prevent washouts. 5. Please provide the 10-day snowmelt HydroCAD results. 6. All water quality requirements are being met. S:\CommwityDevelopmmt\Projeas\Plwning Cases\St. Clair Estates\Staff Reports\20160713 PZ (continued Pl3)\2 20160707 Engineering Review No 2 St Clair