Thursday, February 4, 2010

California, What Are You Doing?

California’s natural hydrology is too limited to support growth in population, industry, and agriculture and possibly the current level of water use. Not only is California relative arid, but subject to, seasonal and climatic variability that threaten a reliable water supply. Approximately 70 percent of the State’s average annual rain and snow melt runoff occurs north of Sacramento, while about 75 percent of the State’s urban and agricultural water needs are to the south. Most of the State’s precipitation falls between October and April with half of it occurring December through February in average years. Yet, the peak demand for this water occurs in the summer months. Climatic variability includes dramatic deviations from average supply conditions by way of either droughts or flooding. California has dealt with the limitations resulting from its natural hydrology by developing an intricate system of reservoirs, canals, and pipelines under federal, State and local projects.
However, a significant portion of California’s water supply needs is also met by groundwater. Typically, groundwater supplies about 30 percent of California’s urban and agricultural uses. In dry years, groundwater use increases to about 40 percent statewide and 60% or more in some regions. California is mining its groundwater, using it at a rate higher than can be recharged. The groundwater in California may be a relic of the last ice age and is not being replaced or likely to be replaced under the current climate conditions.
For more than a half a century the Central Valley of California has been one of the most productive agriculture regions of the world. This has been made possible by the ample supply of water used for irrigation. On less than 1% of the total farmland in the U.S. the Central Valley produces 8% of the agricultural output (as measured by value). In 2002 this translated to $17 billion in crop value. This is all made possible by a combination of surface water diversions and groundwater pumping. Approximately one sixth of the irrigated land in the United States is in the Central Valley (Bureau of Reclamation, 1994) and approximately one eighth of all groundwater pumped in the United States is pumped in the Central Valley. It is possible that this irrigated agricultural model is not sustainable. California's current budget crisis have brought to the forefront the idea that federal taxes on the citizens of California support a disproportionate amount of the federal budget (an argument for smaller government). When will California realize that they have spent a sizable amount of their non-renewable water subsidizing the ranch landowners and cost of food in America.
When you withdraw the groundwater from fine-grained compressible confining beds of sediments and do not replace it, the land subsides. The incredibly fertile Central Valley was identified by the research efforts of Joseph Poland as the location of maximum subsidence in the United States. Once the land subsides, it looses its water holding capacity and will never recover as an aquifer. Groundwater mining in the Central Valley has slowed, at least until the recent water crisis. In 2007 the USGS estimated the rate of groundwater mining to be only 300 cubic feet per second. This change is due to the surface water agricultural deliveries of 13,000 cubic feet per second while groundwater irrigation deliveries are now (or at least were) at 5,900 cubic feet per second.
Nonetheless, the clock is running. California’s non renewable water resource has been subsidizing the food budgets of America. California has been using up their water to produce cheap food for America and make ranch owners (the term for the mega farmers in California) richer. California is squandering its future and making decisions that almost certainly will require desalinization to support the population unless they recognize the true cost of water and make realistic decisions on its allocation.

No comments:

Post a Comment