During this third year of drought in California, there understandably has been much concern expressed by the media and others over the volume of groundwater pumping and its effect on our aquifers.
The Oakdale Irrigation District recently completed its fall readings of the groundwater levels in 20 agricultural deep wells located throughout the district. I thought the public would be interested in the results.
OID, as well as all other irrigation districts, measures groundwater levels in the spring and fall each year. The data is then reported to the state.
The spring reading represents the “best” condition of the groundwater level, after it’s had a chance to rest and recharge over the winter. The fall reading represents the “worst” condition of the groundwater level, after up to seven months of pumping during the growing season.
Of the 20 wells OID monitors within its 82,000-acre service area in northeastern Stanislaus County, the average groundwater drop was 2.63 feet from the beginning to the end of the 2014 irrigation season. The worst well had a drop of 8.25 feet. The best well showed a rise of 7.66 feet.
In fact, of those 20 wells, seven ended the season at a higher groundwater level than when they started. Even to the laymen, this would suggest there is much more to learn about the location, characteristics and relationships between different aquifers in our region before we pass sweeping regulations that could limit pumping.
One of the seven wells that rose is near Valley Home, where a number of shallower domestic wells went dry this summer. It increased 1.08 feet from where it started in April. Just a mile and a half out of town, where a nest of other residential wells went dry, the water table around the OID Campbell Deep Well dropped 3.58 feet.
OID has two deep wells in the Paulsell Valley northeast of Waterford, another area in which concern has been expressed about groundwater pumping. Both wells are bounded by new tree plantings outside the OID service area that are dependent upon groundwater.
The well in the southeast corner of the valley showed a drop of 7.67 feet in elevation. OID’s other well, located in the north central area, showed a rise of 4 feet during this irrigation season. Go figure.
All the recent data about our well levels comes after a season in which OID pumped more than 16,000 acre feet of water, about 7 percent of its total water supply this year. Because of the drought, that number went up. In average years, groundwater makes up only 2 percent of OID’s water supply. A pittance in the water business.
In OID’s portion of Stanislaus County, our data shows that groundwater, on average, was 74 feet below the surface 10 years ago. Today, it’s at 88 feet. The underground resources beneath OID are falling about 1.4 feet per year. That’s not a positive trend and it’s one we need to address in the coming years, but it’s not an “emergency” situation as has been the focus of many media reports.
So what’s the take away? The sky is not falling, but concern over groundwater use and replenishment is valid. Water – from surface sources as well as what’s pumped from underground – is a fundamental part of the health of our cities and their residents, our farmers who are the backbone of the regional economy, and the rivers that sustain fisheries and provide recreation.
This issue is multifaceted; solutions will take time. We’re not going anywhere, so let’s make decisions with facts in our pockets and with an open mind. Efforts are underway locally to get to that endpoint.
I believe we have the resources to address and correct the drops in groundwater levels. The only big gorilla in the way of that success will be our own state government, which wants to take 40 percent of all water in our region and send it out to the ocean for fish. In the state’s mind, a healthy fishery is more important than a healthy economy. State water officials intend to start that effort in February. That’s an issue that has enormous economic implications for our region and will have a devastating effect on both our local surface and groundwater supplies. We urge everyone – farmers, public officials, business leaders and city residents -- to unite against this folly.
Steve Knell is general manager of the Oakdale Irrigation District.