Agenda - Environmental Policy Board - 08/04/2014

Home

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] (f) (i) (i) (2) Where vehicle fueling and maintenance occur (3) With less than three (3) feet of separation distance from the bottom of the infiltration system to the elevation of seasonally saturated soils or the top of bedrock (4) Where high levels of contaminants in soil or groundwater will be mobilized by the infiltrating stormwater (e) All calculations and information used in determining these peak storm discharge rates shall be submitted along with the stormwater pollution control plan. The applicant shall consider reducing the need for stormwater management facilities by incorporating the use of natural topography and land cover such as natural swales and depressions as they exist before development to the degree that they can accommodate the additional flow of treated (e.g., settled) water without compromising the integrity or quality of the wetland or pond. (Commentary: The sensitivity of a wetland to degradation varies with the type of vegetation. Sedge meadows, open bogs and swamps, coniferous bogs, calcareous fens, low prairies, lowland hardwood swamps, and seasonally flooded basins are highly sensitive to degradation. Floodplain forests, reed canary grass meadows, shallow (reed canary grass, cattail, giant reed or purple loosestrife) marshes are only slightly sensitive to degradation. See the current version of the Minnesota Pollution Control Agency's publication "Storm -Water and Wetlands: Planning and Evaluation Guidelines for Addressing Potential Impacts of Urban Storm -Water and Snow -Melt Runoff on Wetlands" for details.) (g) The following stormwater management practices must be investigated in developing the stormwater management part of the stormwater pollution control plan in the following descending order of preference: (1) Protect and preserve as much natural or vegetated area on the site as possible, minimizing impervious surfaces, and directing runoff to vegetated areas rather than to adjoining streets, storm sewers and ditches; (2) Flow attenuation of treated stormwater by use of open vegetated swales and natural depressions; (3) Stormwater wet detention facilities (including percolation facilities); and (4) A combination of successive practices may be used to achieve the applicable minimum control requirements specified in subsection (a) of this section. The applicant shall provide justification for the method selected. (h) The stormwater controls for new development sites shall also provide no net increase in stormwater discharges of Total Suspended Solids (TSS) and Total Phosphorus (TP). The stormwater controls for redevelopment projects shall achieve a net reduction from pre - project conditions (on an annual average basis) of: (1) Stormwater Discharge Volume (2) Stormwater Discharges of TSS (3) Stormwater Discharges of TP The City will evaluate requests for a variance to the volume reduction goals when site conditions preclude infiltration. The developer shall implement to the maximum extent practicable other volume reduction techniques on site. The Lower Rum River Watershed Management Organization has adopted procedures for making a financial contribution when volume reduction goals cannot be met. The variance approval and Ramsey, Minnesota, Code of Ordinances Page 9