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  • Fig 20.3 Groundwater and surface water flow system. <br />
  • Drop tubes <br />

Water slides Water slides Presentation Transcript

  • Water Issues
  • What’s special about H2O? Heat capacity Universal solvent Exists in all 3 phases at normal Earth surface temperatures  Solid H2O is lighter than the liquid H2O  Sunlight penetrates water   
  • The earth is 71% covered by water... Earth is the only planet known to have water in all three phases (gas,liquid and solid) It never disappears, as it is perfectly recycled
  • A water shortage?  With a planet covered in water?  With perfect solar powered recycling taking place constantly?  HOW can one claim that water is a resource in crisis?
  • The Water Cycle... Perfect recycling Ecclesiastes 1:7  All the rivers run into the sea; yet the sea is not full; unto the place from whence the  rivers come, thither they return again
  • Precipitation Evapotranspiration Runoff Streamflow Recharge Recharge ater ndw u Gro Groundwater Terms
  •    Ocean water 97.2% Polar Ice 2.15% 97.2 + 2.15 = 99.35%  .65% of global water supply is the amount generally available for human use.
  • The problem(s) with water…  Uneven Distribution… some areas have too much water, others much less than necessary  Water Quality: When it is present, the water is often in a condition that makes it unacceptable for specific uses… e.g. salty or polluted or full of sediment
  • The approximate location of the 100th Meridian… the traditional dividing line between the humid east and the arid west
  • Comparison:  Florida – East, wet – Abundant water, groundwater  Southern California – West, dry – Scarce water, groundwater
  • Water Laws… east vs. west  East of the 100th Meridian in the US, water is generally abundant  The law governing water allocation in the East is the same as in Europe… the RIPARIAN DOCTRINE  West of the 100th Meridian, water is governed by an entirely different set of assumptions Prior Use doctrine or APPROPRIATION DOCTRINE
  • Riparian Doctrine  Water flowing in defined watercourses is treated under riparian doctrine.  Rights arise from ownership of real property underlying or bordering a stream or river.  A riparian right is the right to use water flowing in a stream on riparian land. No right to divert a specific quantity of water is obtained.  A riparian may use all water necessary for domestic use (drinking, bathing, cooking, laundry, livestock watering, and other uses essential to the preservation of life and health).  If there is insufficient flow to maintain all domestic and non-domestic uses, domestic uses have priority.
  • Riparian Doctrine contd.  Riparian users are entitled to "reasonable use" which may cause some diminution of streamflow so long as other riparians are not "unreasonably" harmed.  The landowner does not own the water itself but rather the right to use it on his riparian land.  Based on English ‘Common Law’ adjudicated in the courts
  • Appropriation (Prior Use) Doctrine  First in time of use is first in right (i.e., the earliest appropriator on a stream has the first right to use the water), and  Application of the water to a beneficial use is the basis and measure of the right.  The law in virtually all western states.
  • Water in the west…  Eighty percent of the Nation’s water is used in the West—most of it for agriculture  Water left in the stream is considered ‘wasted’  Water rights exist as a legal entity independent of the land.
  • BLUE states generally use riparian doctrine. GREEN states generally are considered regulated riparian. RED states generally use the prior appropriation doctrine. GRAY states use mixed approaches.
  • Defining ‘beneficial’  Beneficial use has two components: the nature or purpose of the use and the efficient or non-wasteful use of water.  Keeping water in the stream is considered ‘wasteful’  The issue of anadromous fish!
  • Water and Wildlife  The special case of Salmon in the Pacific Northwest  In the Columbia River basin, development was modeled on the Tennessee River system  The entire river system is controlled by a series of dams that provide hydroelectric power, make the river navigable and provide ‘recreation’ opportunities
  • Salmon…. More than resource… a spiritual identity for the region
  • “IN Stream flow”  There is a benefit to fish (esp. temperature sensitive fish species like salmon and trout) of keeping water in the stream  This benefit can be expressed in economic terms  Some of the most successful programs transfer $ from advocacy groups to ranchers to purchase forage crops for their cattle… forgoing using their water rights to irrigate pastures/hay fields.
  • Water...
  • Water Use: Withdrawal vs. consumption irrigation consumes the highest percent (81 percent) commercial the lowest (1 percent) The difference between the volume of water withdrawn and that consumed is the return flow.
  • Irrigation 81% of water used for Irrigation is ‘consumed’... Removed from the water system (evapo-transpiration) and it is by far the most consumptive use of water. Technology has made irrigation much more efficient.... Drip Irrigation has single emitters for each plant
  • Flood or Furrow Irrigation
  • Spray Irrigation
  • Center-Pivot Spray irrigation
  • Drip Irrigation
  • Domestic water use Our society consumes 50100 gallons per person, per day. This pie chart shows how an average home in Akron, OH uses water (src: USGS). Figure 15.28, S&S p. 538
  • How much water is consumed? How much is returned to the hydrologic cycle?
  • Point Nonpoint
  • Issues: non-point source pollution  The 1977 “Clean Water Act” provided federal guidelines and control over point source pollution.  Non-Point source pollution... Who is responsible? How can it be controlled?  Agricultural land use... The sacred institution of ‘the family farm’
  • Ground Water…  According to the USGS, in 2000 21% of water used in the United States  69.8 Billion gallons /day came from groundwater sources  68 percent, was used for irrigation  19 percent was used for public water supplies  99% of ‘self supplied’ water sources were ground water (a well)
  • Groundwater • Occurs below the water table, where the soil is saturated • Aquifer = underground zone where water can be extracted at useful rate • Depletion by wells causes drawdown a cone of depression in the water table S&S Figure 15.12, p. 519
  • Saturated zone, Saturated zone, Water Table
  • Groundwater & surface water flow system © 2003 John Wiley and Sons Publishers Water table
  • http://ga.water.usgs.gov/edu/wugw.html
  • Ground Water Withdrawals by State, 2000
  • Groundwater ‘mining’...  In some areas, notably the Ogallala Basin in the central great plains groundwater withdrawal has exceeded recharge of the aquifer.  Wells are constantly drilled deeper, bigger pumps installed... The end of a region?
  • The Ogallala Aquifer • Composed of water bearing sands and gravel, i.e. groundwater • …filled during melt of ice sheet in last ice age. • …current 20 x overdraft, -> 1.74 feet per year (1,082,631 acre ft). – North Plains Groundwater Conservation District (http:// www.npwd.org) “Ground water mining”
  • --(Guru 2000)
  • Cost of water?  Abundant water is available virtually everywhere on the planet…  Cheap water is available in only a limited number of places  Water will run uphill to $  The Los Angles Basin sits next to/on the largest body of water on the planet! But ocean water is salty…the technology to remove salt is simple and available… however it is expensive. It is cheaper to acquire water from other regions and ship it.
  • Cost of water…  If the cost of water is not reflected in its allocation then inefficiency is bound to occur.  Irrigation rights… no additional cost for the last water used…. There is no incentive to conserve.  Subsidized water… some estimates place the subsidy as high as 90% for American agriculture (the farmer pays just 10% of the cost of the water) … incentives to conserve are limited
  • Inter basin transfers  The Owens valley project  North American Water and Power Alliance [NAWAPA]  Making beneficial use of ‘excess’ or ‘wasted’ water.