C153773 Feasibility Study - Laserfiche WebLink

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I I I I I I I I I I I I I I I I I I I not reached its useful service life. Analyses it1dicate this 3,000 lineal feet of 12-inch CIP is in good condition and should have an additional 50 years of useful service life. The 12-inch CIP terminates atthe water treatment plant located at the mouth of the canyon, west of the Town. Raw water is either treated and !:Jumped into the distribution systems, pumped to storage in the operating reservoir, or overflowed back into Bear Creek. Raw water pumped to the reservoir is conveyed through approximately 1,000 lineal feet of 6-inch pipe and 1,000 lineal feet of 4-inch pipe. Both the 4 and 6-inch pipes are corroded, and the reported pumped flow rate is less than 200 gpm. The Operating Reservoir was constructed in 1981(6), This reservoir is located downstream (easterly) of the water treatment plant. Altho\Jgh the site did not provide an efficient reservoir (from a cost-to-volume standpoint), it is in a very strategic location for Morrison in that it provides both needed water source storage and also results in reliability of the raw water delivery system - to be used in case of outage of the intake Or transmission facilities. Present fill rate is limited by the old 4 and 6-inch lines. A 10 horsepower low-head pump delivers water back to the plant through the same line. G. WATER TREATMENT PLANT The Morrison water Treatment Plant was constructed in 1974(3). It is a 0.5 MGD rapid filtration plant, built in a modular fashion to allow expansion to an ultimate 2.0 MGD capacity. The water plant processes are chemical addition and flocculation, sedimentation, filtration, and chlorination. The chemicals typically added are powdered activated carbon, alum (aluminum sulfate), soda ash (sodium carbonate), and polymer (polyelectrolyte). The treated water pump lifts the water to the main storage tank. Water level in this tank automatically controls the plant operation. The quality of the water produced from this plant is good when operated carefully. The quality of raw water directly from Bear Creek can vary substantially from day to day, and even hour to hour, during certain times of the year. SUl11mer thunder storms create a very turbid water condition in Bear Creek in a matter of hours due to the steep slope of the stream basin. Snowmelt also creates poor water quality d\Jring the runoff season, particularly after sudden warming trends. During these periods, immediate attention must be given to the plant operation to properly adjust chemical additions to cOl11pensate for the poor raw water quality. During 70-0SO.035:MSTR:PLN II-IO