“The Earth's surface is 71 percent covered in water, and water is the primary force shaping every element of the character of the planet — the geology, the weather, the range and variety of life, the planet's gleaming profile in space…”
…”The total water on the surface of Earth (the oceans, the ice caps, the atmospheric water) makes up 0.025 percent of the mass of the planet — 25/100,000ths of the stuff of Earth.”
“…Scientists don't agree on the precise age of the water on Earth, but it's certainly 4.3 or 4.4 or 4.5 billion years old. It's one of the more astonishing things about water — all the water on Earth was delivered here when Earth was formed, or shortly thereafter…in the first 100 million years or so. There is, in fact, no mechanism on Earth for creating or destroying large quantities of water. What we've got is what's been here, literally, forever…”
The quotes above are from Charles Fishman’s book, The Big Thirst: The Secret Life and Turbulent Future of Water. It is a very elegant and well researched story of how water is used throughout our economies and is the basis of all life and wealth. However, his discussion of water does not clearly focus on the sustainability of our water supply. Mr. Fishman clearly identifies that the water infrastructure is not being adequately maintained in the United States and does not adequately exist in much of the rest of the world. Vast amounts of water leaks from our delivery system, but is not necessarily lost from the water cycle. The real problem is that we are not only mining our water reserves, we are destroying the methods that nature stores fresh water that allows us to have a predictable and reliable supply of water. We as a nation and mankind need to address both problems. The need for water is constant it does not come and go with the weather. The need for water grows with population and wealth. All the ways that water supports our lives are discussed in the book making it well worth reading. There is adequate fresh water in the United States, but it is not delivered uniformly or when we need it. The Mississippi has flooded vast portions of the Midwest while Texas has been having a drought.
Water is our most valuable resource and how we manage its use or allow its abuse may determine the fate of our country and mankind. According to the US Geological Survey about 26 % of the freshwater used in the United States in 2000 came from ground-water sources; the other 74 % came from surface water. Groundwater is an important natural resource, especially in those parts of the country that don't have ample surface-water sources, such as the arid West and in times of drought. Groundwater is a renewable resource, but not in the way that sun light is. Groundwater recharges at various rates from precipitation. The actions of man can impact the recharge rate of groundwater. Changing land use and increasing the amount of impermeable area by paving or building can reduce groundwater recharge.
When you withdraw the groundwater from fine-grained compressible confining beds of sediments and do not replace it, the land subsides. In the pursuit of wealth the ground water in the incredibly fertile Central Valley was pumped to such an extent that the ground subsided more than 75 feet in some places. The area was identified by the research efforts of Joseph Poland as the location of maximum subsidence in the United States due to groundwater mining. Once the land subsides, it looses its water holding capacity and will never recover as an aquifer. Groundwater mining in the Central Valley was believed to have slowed in the past few decades, but it continues as documented by the recent data from the University of California’s Center for Hydrologic Modeling Gravity Recovery and Climate Experiment, GRACE.
The twin satellites of the GRACE program monitor each other while orbiting the Earth, and produce some of the most precise data ever collected on the planet’s gravitational variations. This information is used to determine the changes in ice, snow, groundwater basins, and surface water from season to season and over time. Though the amount of water on Earth is static, the location of the water and its availability for use by man does change. The GRACE program reports that from October 2003 to March 2010, aquifers under the state’s Central Valley were drawn down by 25 million acre-feet — almost enough to fill Lake Mead, California’s and the nation’s largest reservoir. The GRACE program also identified several other areas of the earth where groundwater levels have fallen. These areas include northern India, North Africa, and northeastern China.
California is my usual canary in the mine for water resource management and mismanagement. They have all the resources of knowledge and wealth available to mankind and yet struggle with the politics of addressing their impending water crisis. California local water agencies have invested in water recycling, conservation, groundwater storage and other strategies to stretch supplies, but the demand for cheap water exceeds supply as evidenced by the unsustainable groundwater usage. Year round agriculture that supplies food to the nation (grapes, almonds, avocados, lemons, melons, peaches, plums, and strawberries, oranges, apricots, dates, figs, kiwi fruit, nectarines, olives, pistachios, prunes, and walnuts, garlic, tomatoes, lettuce, cattle and calves) has been made possible by the ample supply of water used for irrigation. The limit to California’s agricultural bounty and the wealth of the ranch owners is water availability.
The water available is a combination of surface water diversions and groundwater pumping. In 2006 before the beginning of the last drought, California used almost 31 billion gallons of water a day for irrigation. This is 351 gallons of water a day for each agricultural dollar earned each year and represents almost 80% of the water used in the state each year (excluding non consumptive power usage). All attempts to reduce water usage have been directed to California residential communities to reduce their per capita water use 20% by 2020. The water that is allocated to agriculture remains cheap water. Food needs to reflect the real cost of the water and the permanent loss of ground water. There is not enough water to support the total level of agriculture in the state. Even as the per capita water usage falls the total water used will grow with the population, but there will be no growth in the water supply for the state and if climate projects are at all true, then there will be less water delivered by snowfall and rain. As documented by GRACE California has continued to make up the short fall in water by using more groundwater than recharges and the groundwater table continues to fall. Water is wealth and life. California is spending its wealth on agriculture in the Central Valley growing cheap walnuts for China and grapes and strawberries for me and when it is gone they will leave behind a desert with water pipes running south to Los Angeles.