6.2. SR 11-19-2007 - Laserfiche WebLink

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INTRODUCTION Since 2003, the MPCA has required municipalities with a population hetween 10,000 and 100,000 to secure a Minnesota Pollution Control Agency (MPCA) permit authorizing discharge of storm water from their municipal storm drainage system to waters of the state. This authorization occurs under the National Pollutant Discharge Elimination System (NPDES) program. These municipal systems are known as Municipal Separate Storm Sewer Systems or MS4s. In 2003, the MPCA was sued by the Minnesota Center for Environmental Advocacy aver the State's alleged noncompliance with its nondegradation rules. As part of the court action, the Minnesota Court of Appeals ruled specifically that the permit issued by MPCA to conditionally authorize storm water discharge from an M54 system under the NPDES program had to address nondegradation requirements in the rules. To comply with the court action, the MPCA revised the NPDES permit program in 2006 to require 30 municipalities across the state, whose storm water discharges are permitted through the M54 program, to complete additional work called a "Nondegradation Review" that will enable the state agency to determine if nondegradation rules are being met. MPCA selected these 30 MS4s based on their assessment of those communities most likely to have expanded storm water discharges to surface waters as reflected hy: 1. population changes since 1990, 2. current population, and 3. projected population growth to 2020. Elk River is one of the 30 permitted M54s to which this Nondegradation Review requirement applies, MS4s must complete a Nondegradation Report when their Loading Assessment indicates they have significant new and expanded discharges. Elk River's loading Assessment calculates new and expanded discharges of pollutants to certain water bodies. In some cases these new and expanded discharges are clearly significant. For this reason the City of Elk River includes this Nondegradation Report with its Loading Assessment. The Nondegradation Report must propose BMPs that address nondegradation far inclusion in Elk River's Storm Water Pollution Prevention Program or SWPPP. As a par[ of minimum control measure 5 in the City's existing SWPPP several BMP summary sheets were developed dealing with stormwater management for new development and redevelopment. Elk River's Nondegradation Report includes a discussion of potential BMPs to attain 1988 levels for total phosphorus (TP), total suspended solids (TSS), and water volume. Elk River has also developed new BMP summary sheets for inclusion in its SWPPP and these are attached to this Nondegradation Report. These BMP summary sheets are not for the actual landscape BMPs that attain 1988 pollutant loads. Rather these BMP summary sheets describe the development of official controls that lead to these landscape BMPs and build on the BMP summary sheets Sa-1, 5b-1 and 5c-1 already developed. These new official controls focus on new development, thus mitigating the impacts of future growth. These official controls also focus on redevelopment through the creation of a redevelopment ordinance that seeks water quality retrofits on a sliding scale. The city intends that the new development strategy apply uniformly throughout the city but that the retrofit strategy will be focused in areas where new and expanded discharges have occurred. E!k River 1482-0 70 0 1 Nondegradation Report page 1