Agenda - Environmental Policy Board - 08/04/2014

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Sec 117.384 -410 Revised July 29, 2014 to include 2013 Construction Stormwater Permit, 2013 MS4 Permit requirements and 2012 LRRWMO Third Generation Plan [ate, additions] filters, up -flow chambers, hydro - cyclones, swirl concentrators or other appropriate controls. Such water shall not be discharged in a manner that causes erosion or flooding of the site, receiving channels, adjacent property or a wetland. (18) All storm drain inlets must be protected during construction until control measures are in place with either silt fence or an equivalent barrier that meets accepted design criteria, standards and specifications as contained in the latest version of the Minnesota Pollution Control Agency's publication, "Protecting Water Quality in Urban Areas." (19) Roof drain leaders. All newly constructed and reconstructed buildings must route roof drain leaders to pervious areas (not natural wetlands) where the runoff can infiltrate. The discharge rate shall be controlled so that no erosion occurs in the pervious areas. (20) Follow -up inspections will be performed by the city on a regular basis and after a 0.5- inch rain event to ensure that erosion and sediment control measures are properly installed and maintained. In all cases the inspectors will attempt to work with the developer and /or builder to maintain proper erosion and sediment control at all sites. a. The city has established a system of notices for enforcing erosion control. b. In the event these notices are ignored, construction stop orders may be issued by the city, until erosion and sediment control measures meet specifications. A second erosion and sediment control /grading inspection must then be scheduled and passed before the final inspection will be done. (21) Removal of more than one acre of topsoil shall not be done, unless written permission is given by the city engineer. Excessive removal of topsoil can cause significant soil erosion problems. (22) Inspection and maintenance. All stormwater pollution control management facilities must be designed to minimize the need of maintenance, to provide easy vehicle and personnel access for maintenance purposes and be structurally sound. These facilities must have a plan of operation and maintenance that ensures continued effective removal of the pollutants carried in stormwater runoff. The city or its designated representative shall inspect all stormwater management facilities during construction, during the first year of operation and at least once every five years thereafter. The city will keep all inspection records on file for a period of six years. It shall be the responsibility of the applicant to obtain any necessary easements or other property interests to allow access to the stormwater management facilities for inspection and maintenance purpose. (Code 1978, § 9.27.10; Ord. No. 06 -32, § 1, 11 -28 -2006) Sec. 117 - 392. - Permanent stormwater pollution controls. (a) The applicant shall install, construct, or pay the city fees for all stormwater management facilities necessary to manage increased runoff from development. -SG that the discharge rates' from stormwater troatment basins . Hydrologic and hydraulic design calculations must be submitted for the pre - development and post - development conditions for the 2, 10, and 100 year events as well as the 10 day snow melt event. Such calculations shall include: (i) description of the design storm frequency, intensity and duration, (ii) time of concentration, (iii) Soil Curve Numbers or runoff coefficients, (iv) peak runoff rates and total runoff volumes for each watershed area, (v) infiltration rates, where applicable, (vi) culvert capacities, (vii) flow velocities, (viii) data on the increase in rate and volume of runoff for the design storms used, and (ix) documentation of sources for all computation methods and field test results. These predevelopment rates shall be based on the last ten years of how that land Ramsey, Minnesota, Code of Ordinances Page 7