The State of California continues to experience serious to extreme drought conditions. Rainfall during the past winter did little to remedy the situation. But, according to a recent article in the June 28 edition of the Washington Post, there may be light at the end of the drought tunnel.
Stanford University professors in a study published recently by the National Academy of Sciences indicate that previously unrecognized significant groundwater resources occur at depths of 1,000 to 10,000 feet below California’s Central Valley. One researcher indicated that there definitely is enough extra groundwater to make a difference for the drought and farmers.
The study was not based on new information but rather on an examination of oil and gas drilling records. The researchers examined data from nearly 35,000 deep test holes in the Central Valley and beyond. They claim that about 2,200 billion tons of fresh and moderately salty water exists within about 3,000 feet of the surface.
Other groundwater researchers questioned the findings. The water is likely to be salty. It may be very difficult and expensive to extract. Land subsidence (sinking) may be associated with its extraction.
So who cares about the discovery? I don’t. I’ll weigh in with a few scientific facts about groundwater and a few thoughts of my own. First the facts:
Most groundwater even deep groundwater had its origin on the surface and infiltrated to its present depth.
The deeper the groundwater, the longer time it has been in residence and the saltier it becomes.
Groundwater temperatures increase about one degree with each 100 feet of depth.
When large amounts of groundwater are withdrawn, land subsidence often occurs.
Now a few of my thoughts based on these facts and the study results:
Groundwater at 100 feet of depth in my home state of Nebraska has an average temperature of 55 degrees F. It’s safe to suggest that groundwater from the same depth in California would be about the same temperature. This would indicate that groundwater from a depth of 3000 feet would be about 85 degrees or from 5000 feet, 105 degrees. Both likely are too warm to use on crops even if the water wasn’t salty. Some method for cooling would be necessary. Cooling ponds perhaps? Cost: $$
Groundwater from 3000 to 5000 feet would be too salty for use on most crops. It would require salt removal. A desalination plant at each well site? I don’t think so. Cost: $$$$$
Even if desalination plants were feasible, brines from the plants would need to be removed. Where to? Trucked to the ocean? Disposed at greater depth than the water source? Cost: $$$
It would be necessary to drill a large number of new very deep wells throughout the valley.
Well installation costs including drilling, casing, and pump installation would be very expensive not to mention operation and maintenance costs. Cost: $$$$
Land subsidence would undoubtedly occur but not for several/many years. Cost: ????
I take no issue with the Stanford study. It adds important information to our body of knowledge of the groundwater of California. What I take issue with is the statement that it will make a difference to the drought and to farmers in the Central Valley. Based on the scientific facts I’ve laid out, it most likely will not make a difference either in regard to the drought or to the farmers. The bottom line is that this groundwater resource most likely is unfit for irrigating crops without creating an enormous financial burden for landowners and crop producers. Because of this, I seriously doubt that the deep groundwater will ever be developed.
This whole issue reminds me of lines from one of my favorite poems, Coleridge’s Rime of the Ancient Mariner, “Water water everywhere, Nor any drop to drink.”
As related to the Central Valley deep groundwater, I submit, “Groundwater, groundwater everywhere, but not a useable drop.”