Tuolumne Utilities District (TUD) is constructing a project to improve water quality and delivery for residents of Columbia. The TUD Board of Directors authorized the construction agreement for the project with Sutton Enterprises of Vallecito, for $479,165, at its June 8th Board meeting and construction started later that month. The project entails installing approximately 1,670 linear feet of 14-inch raw water pipeline, a new reservoir outlet structure, and appurtenances.
The Matelot Ditch, which supplies water to the Columbia Water Treatment Plant (WTP), currently experiences high levels of sediment and other bacteriological contamination. As a result, the WTP must increase the level of treatment to produce water that meets state standards. In addition, much of the sediment, or turbidity, and bacteriological contamination entering the WTP originates from the segment of the ditch that connects the Matelot Reservoir to the WTP. The water delivered to the plant through the pipeline will be less turbid and less susceptible to bacteriological contamination.
Another challenge with the Matelot ditch is a lack of flow control. The ditch operates at a flow rate that exceeds the demands of the WTP, and consequently, large volumes of water flow past the WTP, exceeding the amount needed for downstream users. The new pipeline will allow the District to supply the Columbia WTP with only the volume of water to meet treatment demands, saving as much as 300 ac‑ft per year.
The new raw water pipeline will improve water quality delivered to Columbia Water Treatment Plant and reduce operational water loss in the Matelot Ditch. The Columbia Water Treatment Plant serves the areas of Columbia, Gold Springs, Gibbs Estates, and Saratoga. The District will continue to use the Matelot Ditch to provide water to downstream ditch users. The project is anticipated to be completed by August 31, 2021.