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Review File: Ramsey Elementary School <br />Site Plan Application <br />Engineering Review <br />December 21, 2017 <br />Page 4 of 6 <br />C1.61 <br />Silt Fence must be inspected and approved by the City prior to commencing any work on site. <br />Provide the SWPPP narrative for review prior to final plan submittal. <br />Email inspection logs to the City after every inspection. A complete set must be submitted before <br />Certificate of Occupancy is issued. <br />The City of Ramsey must approve the NOT before it is submitted. <br />Update sheet numbers in the narrative. Reference is made to sheets that are not in the current <br />submittal. <br />C2.11 <br />Revise outlet control structure per notes on C1.51 and Stormwater Management Plan <br />Stormwater Management Plan <br />The submitted Stormwater Management Plan consists of a summary sheet tabulating the existing <br />and proposed flows, drainage diagrams, HydroCAD printouts for existing and proposed conditions <br />and storm sewer design calculations. The manual also includes the geotechnical reports. <br />The stormwater plan does not include a narrative describing the stormwater treatment options <br />employed. This project is in the Lower Rum River Watershed Management Organization <br />(LRRWMO) jurisdiction. The LRRWMO stormwater requirements are: <br />• Infiltration of the first 1" of runoff from all new impervious surfaces. <br />• Stormwater treatment facilities shall provide at least an annual removal efficiency of 60% <br />phosphorus and at least an annual removal efficiency of 90% total suspended solids. <br />• Rate control to below or equal to existing runoff rates for the 2, 10 and 100 year storms as <br />determined using the Atlas 14 24 hour storms. <br />• This site is tributary to Trott Brook which has a TMDL for dissolved oxygen. <br />A MIDS model, P8 Model or other calculation method is required to demonstrate compliance with <br />the removal efficiencies and to aid the City in TMDL reporting requirements. <br />The HydroCAD model lists the pond as a wet pond with a starting elevation at the outlet elevation. <br />Wet ponds do not receive credit for infiltration. <br />The soils near the pond are generally sandy and the pond will most likely be dry. We commented <br />on the utility plan that the flared end section inverts need to be within 2 feet of the bottom of the <br />