Is the drought over?
You might view that as an insane question given the near record snowfall for modern times in the Sierra and the fact the runoff will be testing levees for the coming months.
But before you get too giddy and think its ok to revert to old water use patterns and plant water guzzling turf all over creation, you might want to remember that there is a lot more to California water than meets the eye.
uThe Central Valley water aquifers during the past four years lost a third of what they did during the previous 50 years according to the United States Geological Survey California Water Service Center.
uDuring four years of drought 37.5 percent of all wells in the state dropped 10 to 49.9 feet with another 12 percent falling 50 feet or more. Among those some plunged over 100 feet.
uIn normal water years, 38 percent of the state’s water supplies come from groundwater. During the drought we took 60 percent of our water from aquifers.
uFrom 2013 to 2016 ground water fell by more than 40 million acre feet. Storage in the state’s largest reservoirs during the same time period fell in the highest years of loss to as much as a third of average. If the loss were a third of average for ever year that would translate to 20 million acre feet of water loss in reservoirs from 2013 to 2016.
uWhile one heavy year of snow and rain as we are now experiencing can bounce surface water reservoirs and lakes all the way up to the brim, it takes years to decades for underground water to be replenished according to the Center for Watershed Sciences at the University of California, Davis.
uIn some cases, the loss of water leads to severe soil compaction meaning some ground permanently losses the ability to hold water.
What this means is simple. The meteorologist on TV may tell you the drought is over and so may your own eyes.
But a hydrologist who looks at the entire water system that includes manmade as well as nature both above and below ground will tell you different.
Then there are other nagging little issues we all like to ignore when lakes are full and it’s a sunny semi-warm day with fluffy clouds in the sky and 20 feet of skiable snow in the Sierra.
Scientific research on tree rings point to the past 200 years of being abnormal for the West in terms of the abundance of precipitation. Mega-droughts historically are more the norm. They typically run 50 years or more with slight disruptions of one to three years.
Then there are the manmade problems. Decisions regarding the timing of water releases and how it is used can create manmade droughts. We view these in a vacuum as no one ever stops and thinks where fish or the environment would be if it wasn’t for manmade storage and levees. The endangered Chinook salmon, as an example, would likely be extinct.
If you live in Manteca, Ripon, or Lathrop why should this concern you? After all, if you turn on the tap, water flows out.
Ripon happens to get every drop of its water from wells. Manteca gets all of its winter and early spring water from wells and just under half from the ground during the rest of the year. Lathrop relies on ground water mixed with surface water year round with the added problem that dropping ground water increases salt water intrusion from aquifers beneath the Delta.
While local groundwater tables sustained more modest drops — typically under 10 feet — they are not going to bounce back in one year.
There are several reasons for that. The most obvious but the one most can’t comprehend is how water is replenished. Most potable water tables are 100 feet or deeper. That means its source of water — whether it percolates downwards originates in the Sierra or locally — takes a while to reach the aquifer. That translates into years and even decades depending upon the soil and location.
This is the reason the Groundwater Sustainability Act was passed in Sacramento that created a mandate to various groundwater basins throughout the state to strike a balance between what is taken out of aquifers and what flows in. That means a zero change over the course of a year.
In future droughts such a mandate will be impossible to reach without significantly more drastic water use curtailments than California has been under for the past five years.
It also means unless we change our water use patterns for good, growth will be impossible to support especially in communities such as Stockton that rely 100 percent on groundwater without reducing per capita consumption.
That means even if surface water is plentiful, groundwater won’t be. This is a big deal when 38 percent of our water in a non-drought year comes from beneath the surface.
This will also lead to an increase in pressure to switch to surface water that could put demands on reservoirs in normal water years that mimic the pressures we’ve seen over the past five years.
There are only five viable solutions: Recycle and use treated wastewater, recharge groundwater with treated recycled wastewater, desalination, create more surface storage, and further per capita water use reductions through passive and non-passive conservation measures.
Again, is the drought over?
Despite the epic snow and rain it’s just only starting.