2003-04-09 CC Packet - Laserfiche WebLink

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be difficult to re-fill the tower in a timely manner. Also, the length of main would put the tower ,-- somewhat at risk from isolation in the event of a main break. At a minimum, it is recommended that the p~JLsed water main improvements from Eagle Trail and Brian Drive be constructed to the JLast to tie into the existing 12-inch main on 20th Ave North. With this improvement in place, the tower would be looped and the fire flow capabilities between the tower and City Hall would be greatly improved. As a further improvement, it is recommended that a 12-inch main be placed '---- along Dupree Road and Center Stree~ to fully complete a 12-inch loop. This last improvement would increase fire flow capability to the area west and south of the city hall. The proposed Outlot A tower site has had some fill imported but still remains relatively low. It will be necessary to construct the top of foundation at an elevation of at least 3-ft. above the 100-year high water level. We believe that this elevation will put the top of footing elevation approximately level with 20th Ave North which is approximately 4 ft. above the current site elevation. Borings taken in the fall of 1998 indicate that the site consists of several feet offill overlying at least 12 feet of lean clay with blow counts ranging from 4 to 11. The clay material should provide adequate bearing strength for a 500,000 gallon tank. The second potential tower location is ?irectly south of City Hall. This location will also work for a future elevated tower. There are some restrictions, however, on this tower's construction as related to watermain improvements. If this tower is constructed in conjunction with all of the watermains recommended in the previous paragraph, then this tower location also provides excellent fire flow to the Industrial Park area as well as improved fire flow to the areas west and northwest of the City Hall. However, if this tower is constructed prior to the other watermain improvements, then this tower provides marginal fire protection to the industrial park. In general, it is desirable to have up to 3,500 gallons per minute to an industrial park area. If the City Hall tower is constructed prior to either the 12-inch main on Center Street or the 8 and lO-inch mains east of Eagle Trail, then this will not be achieved. If the tower is constructed after the installation of the 8 and lO-inch mains east of Eagle trail, then most of the industrial park area will be able to receive 3,500 gallons per minute. If the tower is constructed after the Center Street 12-inch connection main, then all of the industrial park will be able to receive 3,500 gallons per minute of fire flow. There is an open site behind City Hall that provides sufficient room for construction of the proposed water tower. The site elevation is approximately 2 ft. below the City Hall elevation. This elevation