SciSun: Everything but the kitchen Sinks   Leave a comment

Today many parts of California are in a deep depression. Not necessarily because the population is sad (although we know of a great resort on the coast you’d be a mad man not to visit); but because some land throughout the state, particularly in central California’s San Joaquin Valley, is sinking by as much as half an inch a month. As more and more groundwater is taken from underground aquifers, this vast storage area is slowly being depleted; and like a sponge set out to dry, as the amount of water in the soil is drained away the land falls into itself creating sinkholes, depressions, or entire areas where the ground is now many feet lower than it was just a few years ago. So for anyone who might be experiencing a sinking feeling, it’s not all in your head. You might really be sinking.

While the current severe drought is partially at cause for extreme water use, not all the blame can be placed on the past four years’ lack of snow and rain: Drought; climate change; increased housing and development; and water-intensive agricultural crops are just as responsible for underground water resources being used even in years when there’s no drought. In 2014, 65 percent of all California fresh water was estimated to come from groundwater sources; it’s projected that amount could reach 75 percent or higher this year, with some towns and areas relying on ground reserves as their only water source. Valuable – and thirsty – perennials like nut trees and grapevines thrive year-round in mild California weather, taking the place of row crops like alfalfa and corn that have shorter growing seasons, naturally use less water and after harvest allow land and reservoirs time to recover.

But even if actions were taken today, it may be too late to restore water resources that are the result of tens of thousands of years of rain and snowmelt. The largest aquifer, under the most stress from over-use, extends for about 400 miles beneath the central portion of California – some of the most productive farmland in America – and this basin is comprised of loosely-packed sand and clay particles, which in their usual state only lightly fit together, like an un-made jigsaw puzzle, forming microscopic cavities where water can be trapped and held. Aquifers; and the ‘water table‘ that is often referred to as available water supplies; is not an empty pool that can be used and re-filled, but a complex system of soil, rock, microscopic channels and individually small bits of water that together combine to form a dynamic system. As wells are dug and water is removed – more than 100,000 wells operating already, with more being dug down to 1,000 feet – the clay particles fall in on themselves, becoming compressed and resulting in subsidence – sinking – of the ground surface. (And, some scientists project, increased seismic – earthquake – activity). Even if water resources were recovered and the aquifer ‘filled’, the soil particles would be altered and stacked together, like a finished puzzle, permanently removing much of the space that previously held water. As the soil is compressed and changed, space for water is lost and the land will never hold as much water as it has in the past.

Sassie may be a very smart dog, but due to sinking ground levels she continually found herself confused and frustrated.

Sassie may be a very smart dog, but due to sinking ground levels she continually found herself confused and frustrated.

This isn’t the first time ground levels in California have sunk; from about the 1900’s when large-scale commercial farming was established; home and commercial development grew; and California was recognized (and advertised!) as the ‘Golden State’ – and continuing though the 1970’s – it’s estimated ground water pumping had reached 125 million acre-feet; an area about the size of the state of Connecticut. An acre-foot is the amount of water it would take to cover an acre of land in a foot of water; which either signifies a major flood, or a lot of water going to grow crops and grass and fill swimming pools. By the mid 1970’s more than 5,200 square miles of land surface was sinking by inches or feet, leading to stress on building foundations, loss of productive land, and bridge and road failures resulting in over 1.3 billion dollars in damages. The 1970’s also saw the skateboard culture, inspired by abandoned and dry swimming pools that owners could no longer afford to fill and maintain, springing up in Southern California. Coincidence?

To avoid a major catastrophe federal government programs including constructing pipelines and channels to bring surface water to the central valleys allowed the continued growth of California commerce and food production that the entire United States now relies upon. But, disaster averted, in a classic tale of ‘Out of sight, out of mind’ (literally!), few steps were taken toward preserving underground aquifers or responsible water use and until just a few months ago California was one of the few western states with no groundwater regulation or monitoring. Hundreds, or thousands, of gallons of water could be tapped without oversight or accountability. In a land of plenty, it’s really been more like first-come, first-serve.

Officially, vast underground aquifers have been considered an emergency resource for a ‘worse-case’ scenario. But today, when we’re facing drought, climate change, growing population, loss of surface water, and a reduction in rain and snowfall, that ‘worse case’ day may have arrived. And with the emergency water already at dangerously low levels, that’s enough to give anyone a sinking feeling.

http://ca.water.usgs.gov/projects/central-valley/land-subsidence-monitoring-network.html

http://newscenter.berkeley.edu/2014/05/14/central-valley-groundwater-depletion-raises-sierra-and-may-trigger-small-earthquakes/

^^^

Michonne Says: The water is under the ground? And the ground is sinking? Maybe the ground is trying to get to the water because when something falls on the water it sinks. But I don’t think water is really under the ground because then there would be nothing to walk on.  And your feet would get wet. 

Posted May 31, 2015 by ECOVIA eco-adventure® in SciSun

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