The fourth consecutive dry year in Northern California has illuminated the pressures on the Sacramento Valley’s water resources and the challenges we face in providing reliable water supplies for various beneficial purposes in the Valley.
Groundwater resources are critical in the Sacramento Valley, with groundwater providing almost 30% of the region’s water supplies in most years, with this percentage increasing during dry years such as 2015 when surface supplies are not available. Importantly, there have only been two wet years so far this century (2006, 2011), which means that our important aquifer systems have not been recharged, either directly or indirectly, as much as we would like.
The Sacramento Valley has historically been in balance with respect to its groundwater resources. In other words, the over-drafting of groundwater resources seen in other parts of the Central Valley have not taken place in the Sacramento Valley. To be sure, groundwater levels have and will continue to decline throughout the Sacramento Valley this summer, as you would expect during a dry period. This is not surprising as similar results were seen in previous dry periods, such as 1976-77 and in the early 1990s. The following map prepared by DWR shows the general well level declines over the past five years.
This map and other information is available at: Department of Water Resources – Groundwater Information Center.
The more important question as we look forward is whether the groundwater levels will recover when we have wetter years in the Sacramento Valley to maintain this balance? In other words, we will keep asking the fundamental question: are we at a tipping point on the sustainability of our groundwater resources in certain parts of the Sacramento Valley?
The counties and water resources managers in the Sacramento Valley are actively monitoring groundwater resources, particularly during this dry period, to better understand this invisible resource, bring greater awareness to its vulnerability, paint a picture of the real challenges we face in preserving our groundwater resources, and provide more sophisticated tools to actively manage our water and land resources for all the beneficial purposes described above.
The preservation of Northern California’s groundwater resources is critical to the economic, social and environmental fabric of the region. As part of ongoing efforts to achieve sustainability, water leaders in Northern California have made a concerted effort over the past several years to assess Sacramento Valley groundwater resources, both for groundwater levels and quality. Our objective is to help bring the region together to actively manage our water resources—both surface and groundwater—to assure sustainable water supplies for cities and rural communities, farms, fish, birds and recreation.