Groundwater’s importance to California extends far beyond wine grapes; it provides up to 60 percent of the total water supply in a dry year.  But after decades of groundwater reliance and insufficient recharge of water back into the ground, many such basins around California are overtapped.  It doesn’t help that groundwater is inherently hard to see, measure and understand. Passage of the Sustainable Groundwater Management Act (SGMA) in 2014 provided a framework to manage groundwater in California by requiring newly designated agencies to create plans to guide each groundwater basin to sustainability.  To implement SGMA, the California Department of Water Resources (DWR) recently released emergency regulationsthat will help local agencies shape the plans. 

But creating a good plan is only the start.  Monitoring is key to a successful outcome. One basic and crucial piece of information that must be gathered is groundwater elevations, or levels. Knowing if aquifer elevations are increasing, decreasing or stable, and where this is happening, alerts managers to the potential for a variety of problems and highlights where management efforts need to be focused. It is hard to overstate how fundamentally important groundwater levels data are to understanding aquifer health. 

DWR’s draft regulations underscore the importance of groundwater levels by calling for “a sufficient density of monitoring wells capable of collecting representative measurements through depth discrete perforated intervals to adequately characterize the potentiometric surface for each of the principal aquifers.”  This basically means having enough monitoring wells for each main aquifer in order to determine groundwater levels.  Understanding the health of each of the different aquifers in a system requires measuring each aquifer separately. This is what a dedicated monitoring well does: it is targeted and screened to a specific aquifer.

While simple in concept, developing a robust system of monitoring wells is not easy or cheap. Dedicated monitoring wells are expensive: one could easily run between $100,000 to $200,000.  Many groundwater basins in California have multiple aquifers at depth, which means that developing a dedicated monitoring well requires drilling separate wells “screened” or perforated to measure conditions for each aquifer. 

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