The depletion of water was first noticed in the mid-1900s. In 1972, the Yellow River in China failed to reach the sea for the first time and this problem is only getting worse. The glaciers that replenish the river are depleting significantly. Ever since the mid-1900s, researchers have begun to notice the amount of drilling and usage has increased and consequently, our water levels have been decreasing. Water tables around the world are falling 3-10 feet per year.
The cause for this depletion stems from many different problems. For instance, farmers need to irrigate their fields, but this irrigation uses an enormous amount of water. The world’s agriculture uses 70% of our freshwater, but if farmers cut down on their irrigation we will be in danger of a food shortage. This is because 40% of the world’s grain is produced on irrigated land; it takes 1,000 tons of water to produce one ton of grain. According to the Earth Policy Institute, “roughly 160 million tons of the world’s grain supply is now being produced by over-pumping. “ That brings me to my next point; aquifers are being over-pumped and drilled deeper each year to supply the amount needed for irrigation and domestic use. According to the U.S. Geologic Survey, “If water is withdrawn from the ground at a faster rate that it is replenished by precipitation infiltration and seepage from streams, then the water table can become lower. The impact on the level of the water table can be short-lived or last for decades, and the water level can fall a small amount or many hundreds of feet.” Not only are aquifers being depleted for the use of irrigation, but residential overuse of water can also affect water levels. Even though only 10% of freshwater is used for residential use, we overuse our water constantly. Showers account for 20% of indoor use, and how many of you know you take a very long shower or could at least cut down on the time? In fact, there are many ways for us to cut down on water usage at home. Just think, the consumption of water is doubling every 20 years - more than twice the rate of increase in population. Also, water can be overused by what some think of as trivial reasons, such as watering a golf course. It takes 2.5 billion gallons of water per day to irrigate the world’s golf courses. It would take 2.5 billion gallons of water per day to support 4.7 billion people at the UN daily minimum. That kind of makes you think, doesn’t it?
Finally, credited as the number one cause of freshwater shortage and water depletion is global warming. It has been said by some scientists that a rise in average temperature in mountainous regions can alter the precipitation amount of rain/snow. This change means more flooding and more runoff during the rainy season, but also less water held as snow and ice in the mountains for use in the dry season. Snow/ice masses are now shrinking at an incredible rate. Many rivers across the world originate from these masses.
Sources:
"The Water Cycle: Groundwater Storage." USGS. 27 Dec. 2011. Web. 08 Feb. 2012. <http://ga.water.usgs.gov/edu/watercyclegwstorage.html>.
"Problem: Freshwater and Oceans in Danger." Web Of Creation. Web. 8 Feb. 2012. <http://www.webofcreation.org/Earth%20Problems/water.htm>.
"Groundwater." ENVIS Centre in Biogeochemistry. Web. 08 Feb. 2012. <http://jnuenvis.nic.in/subject/freshwater/groundwater.htm>.
Shepard, Kenton. "Groundwater Depletion." Peak to Prairie Inspection Service. Web. 08 Feb. 2012. <http://www.peaktoprairie.com/?D=192>.
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