Water Resources

Hydrologic Cycle Evaporation and transpiration Evaporation Precipitation Unconfined Aquifer Recharge Area Runoff Flowing artesian well Well requiring a pump Stream Water table Infiltration Lake Infiltration Unconfined aquifer Less permeable material such as clay Confined aquifer Confining impermeable rock layer Fig. 13-3, p. 316

Ocean water Saline-basically unusable to humans Ocean circulation

Thermohaline Currents—The great conveyor belt

Freshwater Resources Major limiting factor in modern world Access to freshwater divides the haves from the have-nots Plenty of water if we didn’t need electricity and food.

Groundwater: Ground water – Zone of saturation Water table – Aquifers

Use of Groundwater in Saudi Arabia

Ogallala Aquifer largest known aquifer- lies under 8 mid western states from South Dakota to Texas Irrigates the Great Plains Water table lowered more than 30m Cost of high pumping makes it too expensive to irrigate in certain areas. Amount of farmland decreased by 11% Government subsidies to continue farming deplete the aquifer further by encouraging the growth of water thirsty crops Biodiversity threatened in some areas

Freshwater Surface Water Surface runoff – Watershed (drainage) basin – Reliable runoff –

Freshwater conflict on the Klamath River

Fight over Klamath River water distribution in early 2000’s Tribes and environmental groups sued electric company to release water from reservoirs Result of decades of tension between stakeholders.

Historical Impacts of dams on the Klamath river

Stakeholders: Native Americans Traditional uses of salmon fisheries cut short Pollution Temperature change Eutrophication of streams Dams prevent movement

Agriculture Losses of farm income worth $73-$92 million, when government shut off irrigation because of a severe drought in 2000-2001. 13% of jobs in this region are related to agriculture. Irrigation from the Klamath River Basin accounts for half of the agricultural production in this area.

Electric Company Hydroelectric power is a clean way to fuel the area and removal of dams may increase pollution by increasing other means to generate power

Environmental Groups Agricultural runoff fosters massive fish kills. Cattle grazing on river basin land area and can cause eutrophication and contamination through cow feces. 80% of original wetlands lost Water quality degraded; quantity decreased during drought 80% of Pacific Flyway’s waterfowl supported by wetlands Area essential to seasonal migrations: Fall: waterfowl, peaks can reach 1 million birds Winter: bald eagles, largest concentration in contiguous U.S. Spring: waterfowl return, songbirds, shorebirds, one of the few remaining American white pelican breeding colonies Summer: waterfowl and marsh birds

Conclusion 1.1 billion people lack safe drinking water. 66% of total withdrawal of fresh water is used for irrigation, followed by industry, domestic households, and evaporation. Over 260 river basins are shared by two or more countries. Aral Sea, in Central Asia, has lost half its superficies, or 2/3 of its volume, leaving 36,000km2 of land covered by salt ater availability will cca

Dams Release runoff as needed to control: Floods Generate electricity Main goals of a dam and reservoir system Capture and store runoff Release runoff as needed to control: Floods Generate electricity Supply irrigation water Recreation (reservoirs)

Water Use Domestic Indistru Agriculture

Future Will need to begin desalination in near future to provide water VERY expensive