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Technical Memorandum <br />Hydraulic Model Review <br />March 9, 2018 <br /> <br /> <br /> Page 5 of 5 <br /> <br /> <br />x Water storage analysis <br />- Tank levels in Figure 2E show improved storage levels within all of the <br />water tower were able to maintain a minimum level of approximately <br />50% capacity to allow for fire and emergency storage. <br />- As shown in Figure 2F, the system was able to provide capacity for a <br />5,000 gpm fire over duration of 4 hours. <br />Key items to note: <br />1. Under maximum day demand conditions, there is adequate capacity in the proposed system to <br />maintain 50% storage within the water towers with the remaining 50% storage available for fire <br />protection and emergency conditions such as pump station outage or main transmission <br />pipeline break. The top 50% of the storage is used to meet peak hour demands and is typically <br />referred to as equalization storage. <br />2. Analysis showed that the system has the capability to provide 5,000 gpm of fire flow for a <br />duration of 4 hours before the TCAAP water tower would be empty. <br />Conclusions/Recommendations <br />1. The existing system with only water main improvements to the TCAAP site and minimal initial <br />demands has the ability to provide 3,500 gpm of available fire flow for a duration of 3 hours <br />during maximum day demands. Pressures and available fire flows are adequate to meet initial <br />growth within the TCAAP area allowing the ability to phase in the new pump station and future <br />water tower over the next few years as development occurs. <br />2. The existing overall storage capacity within the North and South Water Towers is adequate to <br />provide emergency storage in meeting one average day demand. There is adequate capacity to <br />move water between the two storage facilities. <br />3. Analysis showed that a 12-inch water main along Snelling Avenue was beneficial for maintaining <br />adequate pressures and available fire flow south of the new pump station. The additional <br />capacity is necessary during the operation of the pump station. Along with the improved <br />capacity, the water main will also provide redundancy to this area as well as to the new pump <br />station. <br />4. Water storage analysis based on future growth showed that a 1.0 million gallon water tower in <br />the TCAAP area would provide adequate water storage for daily demand fluctuations during <br />maximum day demand. The capacity would also provide the ability for fighting a 5,000 gpm fire <br />for a period of 4 hours. <br />5. It is recommended that additional analysis be completed to determine the most effective <br />capacity improvements within the Arden Hills and Roseville systems to improve the ability to <br />move water from the Roseville system to the Arden Hills South Water Tower.