C153664 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 . 2. Groundwater Quality Raw water quality in Fort Lupton is generally considered to be poor because of high nitrate levels and total dissolved soli(js concentrations in excess of suggested levels, Though not confirmed by recent data, the City's 1986 Water Service Plan also reports sulfate levels to be in excess of suggested levels, In addition, uranium levels have been reported to exceed the proposed maximum contaminant level (MCL) of 30 pCi/L, The CDPHE has notified the City that Fort Lupton will be expected to comply with the uranium standard once it becomes effective in June 1995. Table 3-2 summarizes recent water quality characteristics measured in Fort Lupton's raw water supply and the MCLs allowed by the SDW A. According to the Water Service Plan, the suspected source of the elevated nitrate levels is the fertilizer used by the agricultural community surrounding the City. High nitrate levels are of concern since levels above 45 mg/L may playa role in c<lusing methemoglobinemia (blue babies) in infants under the age of six months. Consequently, water with elevated levels of nitrate should not be consumed by babies under six months of age or pregnant or breast-feeding women. Historical nitrate concentrations for Fort Lupton are summarized in Table 3-3. The City is required by law to publish quarterly notices that the nitrate concentration in the drinking water exceeds the 10 mg/L limit. Because of the high nitrate levels, the CDPHE has mandated the City take corrective action by contracting with the NCWCD to obtain a l1ew water supply. An enforcement order has been issued to the City for compliance. During the past five years, the average nitrate levels of the City's wells have decreased by approximately 1 to 2 mg/l. Historically, system operators have discovered that nitrate levels in City wells increase with increased pumping. To provide a mixture of water in the distriblltion system with a nitrate concentration below 10 mg/L, rotation of well usage has been practiced. Unfortunately, during the interim period between now and the end of 1996 when a treated water supply becomes available, the City has little rotation flexibility, particularly during times of peak demands when all City wells have to operate concurrently to keep up with the needs of Thermo and the City, The City carefully monitors water quality during this time and practices well rotation whenever possible in an attempt to manage nitrate levels. 25325,100; 12109/94 3-6