09/02/2008 Council Packet - Laserfiche WebLink

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American Water Works Association (AWWA) standards for watermain materials and installation. Ten - States Standards recommend that the minimum size of watermain providing fire protection should be at least 6 inches in diameter. Existing watermains in Lino Lakes appear to conform to Ten States guidelines. While a majority of the distribution network is well looped, the trunk network is not. This is the result of the Rice Creek Chain of Lakes Regional Park being located in the center of the City. There is only a single run of large diameter (16 inch) trunk watermain to convey water from the water production facilities on the south and east side of Lino Lakes to the businesses and residents on the north and west of I -35W. This is the 16 inch watermain that runs along the southwest side of Rice Lake in Hodgson Road. Without the elevated tank on the north west side of I -35W, any disruption in service to the 16 inch watermain crossing would severely impair fire fighting ability on the northwest side of I -35W where there are no City wells as shown in figure 8 -1 above. There is, however, an 8 inch interconnect with the City of Blaine which will ensure an emergency supply of water to this area. Additional large diameter trunk watermain should be added to the system to strengthen and "loop" the existing trunk network. The 2008 Comprehensive Water Supply Plan recommends strengthening of the existing trunk distribution system and will guide the City during future watermain extensions. The Plan's recommendations are shown in Figure No. 8 -4, Proposed Water System. Trunk System: Figure 8 -1 shows the existing trunk system and all inter - community connections. Figure 8 -4 shows proposed water system with trunk lines, raw watermain and the existing interconnections. The redundant trunk lines along Birch Street and 20th Avenue shown on figure 8 -4 allow the City to put in place redundancy for the water distribution system. Redundancy and looping allows a water distribution system to serve all residents when a portion of the system fails or needs replacement. For the eastern part of the City two redundancy alternatives were evaluated 1) North Redundancy through the Regional Park from approximately 80th Street and 20th Avenue to the intersection of Main Street and Rondeau Lake Road West and 2) South Looping along Birch Street and 20th Avenue where a second trunk line of similar size will be installed parallel to the existing system allowing for the desired redundancy. The north redundancy would require crossing a large area of wetlands and low lying areas, which would cost a considerable amount and serve very few residents. While the south option would also have a significant cost this alternative is preferable because of the existing right -of -way and developable areas along Birch Street and 20th Avenue. Currently Blaine and Circle Pines water systems serve a small portion of Lino Lakes. One area known as West Oaks is proposed to be served by White Bear Township until such time that the City connects that area to the City water system. Once the City has connected to that area, an interconnection with White Bear Lake Township will be established. In 2006 White Bear Lake Township constructed water lines with the capacity to serve the approximately 90 homes in the West Oaks area. 8 -15 • •