2012-08-28_PWETC_AgendaPacket - Laserfiche WebLink

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5.0 Issues Assessment 5.1 Resolved Issues & Past Project Examples The following sections provide descriptions of past example projects and resolved issues. Figure 18 identifies the locations of the following examples. 5.1.1 Rosewood Neighborhood Drainage Improvements The existing storm sewer system in the Rosewood neighborhood consists of a network of pipes that lead to a manhole at Draper Avenue and Midland Hills Road. From this manhole, the storm water runoff flows through a dual pipe system west to Walsh Lake. The existing storm sewer system was built in the 1970's and additional build -out of the neighborhood, which included the filling of wetlands, resulted in an under -sized storm sewer system for today's conditions. The pipe configuration at Draper Avenue and Midland Hills Road creates a bottleneck on the system, which causes localized street flooding. The streets in this neighborhood are in good condition; upsizing the entire storm sewer system wouldn't have been a cost- effective manner in which to improve the drainage conditions, as it would have required significant pavement removal and excavation. In addition to costs, upsizing the pipe would increase flow rates into Walsh Lake. Since the outlet of Walsh Lake is controlled by a lift station, increased flow to Walsh Lake could cause significant problems downstream and localized flooding Instead, the City of Roseville installed 19 neighborhood raingardens in the Walsh Lake area to encourage infiltration of stormwater runoff and alleviate frequent local flooding problems. Additionally, alarge underground storage /infiltration device was installed and Rosewood Wetland was expanded to provide additional stormwater storage and treatment capacity in this area. Creating additional storage possibilities throughout the existing storm sewer system alleviated the stress on the existing system; reduced the threat of flooding, while also improving water quality. By creating additional storage to reduce the risk of flooding, street flooding has also been reduced. 5.1.2 Aladdin Street Bioinflltrad on Basin Retrofit Installation A long urbanized area along Aladdin Street in Roseville drains to a wetland which is hydraulically connected to Lake Owasso. To provide water quality treatment for this area the Grass Lake Watershed Management Organization, in cooperation with the Ramsey Conservation District and City of Roseville, installed a bioinfiltration basin with funding provided by the Clean Water Land & Legacy Amendment Fund. 5.1.3 Arena Pond Reconstruction Arona pond is located within the Applewood Pointe redevelopment area. Prior to development, this pond was a landlocked basin. For years, the normal water level of the pond was governed by infiltration. As the surrounding area developed, the basin became a part of Comprehensive Surface Water Management Plan ROSEV120222 City of Roseville Page 27