Water Supply Update - April 7
As the District continues its focus on increasing water supply for greater resiliency in the face of drought and future water shortages, the District is very happy to share news of the recent completion of the Kastania Pump Station Rehabilitation project which was underway late last year and through this past January. This critical project significantly increases the District’s access to supplemental water from Sonoma.
Maximizing Marin Water's Supply Allotment from Sonoma Water Agency
Marin Water has a longstanding partnership with the Sonoma Water Agency which historically provides up to 25 percent of the District’s potable water. The District has a contractual allocation of up to 14,300 acre feet per year of water from Sonoma but typically receives between 5,300 acre feet in normal years and up to 7,700 acre feet in dry years. The limitation in using supplemental water from Sonoma has previously been due to hydraulic constraints (too small of a pipeline) for summertime needs. Through the Kastania Pump station rehabilitation project, the District has enhanced its operational flexibility to accommodate an additional annual water delivery of up to 5,000-acre feet from Sonoma. To provide comparison, the 5,000-acre feet is equivalent to a new reservoir similar in size to the District’s Bon Tempe reservoir provides 4,019-acre feet and is one of the seven reservoirs which collectively make up 75 percent of Marin Water’s overall water supply. Having the operational flexibility via the restored Kastania pump station to receive this additional water greatly improves the overall long term resilience of our water supply.
Potential to Capture Winter Water
Rehabilitation of the Kastania Pump Station also helps provide the District with the potential capability to access extra available water supply from the Russian River during typically wetter months in the winter/spring. This water supply option is something the District is evaluating within the District’s Strategic Water Supply Assessment.
Under this option, the District – in collaboration with Sonoma Water – could look to use “winter water” as a means to drought proof the supply from Sonoma so that even in very dry years the District is able to optimize the volume of water received from Sonoma. Winter water refers to water in the Russian River that is above the minimum in stream flow requirements as a result of rainfall between the months of October and May. Even in very dry years, such as 2013 and 2020, there was considerable winter water flow in the Russian River following rainfall events. To pursue this option, the District and Sonoma Water would need to continue exploring the feasibility of capturing and using this winter water as drinking water during periods of drought.