NID board pushes ahead with mercury removal project at Lake of the Pines |

NID board pushes ahead with mercury removal project at Lake of the Pines

The Nevada Irrigation District board of directors unanimously approved a $5.5 million agreement with the Department of Water Resources’ Riverine Stewardship Program for the Combie Sediment and Mercury Removal Project.

The Combie project is a pilot water supply maintenance project that removes sediment from the reservoir while extracting mercury using an innovative centrifuge technology. This pilot project is estimated to take three to four years to complete.

If the project demonstrates mercury can be effectively removed from river sediments, the process can be applied at other reservoirs throughout the Sierra Nevada, according to NID.

The project actually got under way in July of last year.

NID had been testing the new technology that suctions sediment from waterways and funnels it into a centrifuge machine, which spins and cleans the sediment and removes 98 percent of mercury.

The Combie project puts that new technology to use on a large scale. The district plans to remove and clean 150,000 cubic yards of sediment from the reservoir. The cleaned sediment then will be sold.

Mercury was introduced to the Sierra Nevada during the Gold Rush era, when miners would use it to extract gold from the mountains. Much of the highly toxic metal was left behind, and has led to widespread contamination of sediments throughout the Sierra and Central Valley watersheds, according to NID.

The $5.5 million will be used in site construction and sediment removal and mercury recovery operations. NID will spend nearly $2.2 million on the project, including project management and biological research.

That state funding is reimbursable to NID back-dated to July 1, 2017, the staff report states. The project, including post-project monitoring, will last through 2021.

Raw Water master plan

The board voted unanimously to approve $500,000 to update the Raw Water Master Plan, which charts NID’s course for the next 50 years. The plan is the foundation for future improvements and future service standards for the district. The update process will include public participation to evaluate impacts and alternatives and develop community solutions for short-term and long-term needs.

The general manager reported district water storage is 255,660 acre-feet, which is 95 percent of maximum capacity. As of April 18, Bowman Lake had received 66 inches of precipitation for the season, which is 106 percent of average. Snowpack is well below average for the year.

The next regular meeting of the NID Board of Directors, will be held at 9 a.m. on May 23 (the May 9 meeting has been cancelled) at the NID Business Center located at 1036 West Main St., Grass Valley. NID Board meetings are open to the public.

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