Agenda - Council Work Session - 02/23/2021

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The LRRWMO is within the area included in the MPCA's Rum River Watershed Restoration and Protection Strategies report (Rum River WRAPS, 2017). In support of this study, the MPCA and its partners conducted intensive watershed monitoring in the Rum River Watershed in 2013 and 2014 to determine the overall health of water resources, identify impaired waters, and to identify waters in need of additional protection. This data was combined with other available data collected in the previous 10 years for the purpose of waterbody health assessment. This information is documented in the MPCA's Rum River Watershed Monitoring and Assessment Report (October, 2016) and the MPCA's Rum River Watershed Stressor Identification Study (August, 2016). As part of the WRAPS analysis, the MPCA performed water quality modeling of the watershed to estimate phosphorus, nitrogen, and sediment loading throughout the watershed (including the LRRWMO). Relative to the greater Rum River watershed, the watersheds in the LRRWMO contribute lower phosphorus, moderate nitrogen, and greater sediment loads (MPCA, 2017). The analysis included in the WRAPS is performed at spatial resolution that is too coarse to be used to target specific projects. Generally, however, the WRAPS identifies strategies to be implemented within the Lower Rum River watershed to reduce pollutant loading and protect or improve water quality. The LRRWMO has considered these strategies in developing and prioritizing its implementation program (see Section 5) More information about the MPCA's water quality analysis of the Rum River watershed is available at: tt s:// c .st t n s/ tr/ tars . • s/ru-riv*.r The area within the LRRWMO includes a mix of urban, suburban, and rural land use (see Section 2.3). In developed areas, pre -settlement drainage patterns have been significantly altered as part of development activity, resulting in networks of stormwater management infrastructure designed to collect stormwater and convey it downstream. The stormwater system includes pipes, ponds, lakes, wetlands, ditches, streams, swales, and other drainageways. Ultimately, all stormwater in the LRRWMO is routed to the Mississippi River, either directly or via the Rum River. Various units of government and private entities have jurisdiction over different parts of the stormwater system within the watershed. The Minnesota Department of Transportation (MNDOT) is responsible for maintaining the stormwater systems within their rights -of -way, such U.S. highways (e.g., Highway 10), and state highways (e.g., Highway 47). Anoka County is responsible for maintaining at least part of the stormwater systems within their rights -of -way, such as county roads and county state aid highways. Each city within the LRRWMO has jurisdiction and maintenance responsibility over its own stormwater management systems. These systems include lateral (also called primary) stormwater systems (i.e., street gutters, pipes, and ditches) and outflow (also called main, trunk, or secondary) conveyors, which collect flows from city lateral systems and move the water downstream. Cities generally design lateral stormwater systems with capacity to convey runoff from 5- or 10-year frequency storms without significant flooding and protecting public health and safety for storms up to the 100-year frequency interval (these design 2-33