Dams and Salmon on the Klamath River
hydroelectric dams, in conjunction with the drainage of two large lakes at the river's source for agriculture, impeded the flow of water and prevented the natural migration of salmon to their breeding grounds; conflict over water use between farmers, fish
distribution of water on Earth
97% saltwater, 3% freshwater (1/4 underground, almost 3/4 frozen, remaining <1% accessible for human consumption)
aquifer
small spaces found within permeable layers of rock and sediment where groundwater is located
unconfined aquifer
porous rock covered by soil which water can easily flow in and out of; rapidly recharged by percolation of precipitation
confined aquifer
aquifer surrounded by a layer of impermeable rock or clay that impedes water flow and causes water pressure to build up underground
water table
uppermost level at which the water in a given area fully saturates the rock or soil
groundwater recharge
the input proces by which water from precipitation percolates through the soil into an aquifer
recharge area
opening at the surface of the otherwise impermeable layer covering a confined aquifer
spring
source where water naturally percolates up to the ground surface; crucial to the organisms in freshwater aquatic biomes and can be used by humans for consumption
artesian well
formed when a well is drilled into a confined aquifer and the natural pressure released causes water to rise toward the ground surface (often without any need for pumps)
Ogallala aquifer
largest aquifer in the United States, covering the Great Plains; its rate of recharge is not keeping pace with the rate of water withdrawal = unsustainable
cone of depression
an area where there is no longer any groundwater, caused by the rapid pumping of a deep well which causes adjacent, shallower ones to go dry as the water table lowers
saltwater intrusion
rapid pumping of wells drilled in aquifers along a coastline can lower the water table, which reduces water pressure and allows nearby saltwater to infiltrate the aquifer and contaminate it with salt
floodplain
land adjacent to the river that receives deposits of nutrient-rich sediment from seasonal floodwaters, making the soil fertile
oligotrophic lake
lake with low productivity due to low amounts of nutrients such as phosphorus and nitrogen
mesotrophic lake
lake with a moderate level of productivity
eutrophic lake
lake with a high level of primary productivity
impermeable surfaces
pavement or buildings that do not allow water penetration, typically found in urban and suburban areas (anthropogenic contribution to flooding)
levee
enlarged bank built up on each side of the river to prevent flooding (PROS: flood protection, enables development. CONS: no sediment deposition on floodplains; sediment settling downstream, clogging estuary; forces floodwater to different location downstr
dike
structures built on the shore to prevent ocean waters from flooding adjacent land, especially areas below sea level; can be combined with electric/diesel powered pumps to combat any water that does intrude
dam
barrier that runs across a river or stream to control the flow of water (PROS: hydroelectricity, flood control, water source, recreation. CONS: uses resources and energy; displaces residents; tampers with migratory organisms and their dependents; some rar
reservoir
large body of water stored behind a dam (used for consumption/recreation; can experience adverse environmental effects such as increased temperatures and low dissolved oxygen conditions.)
fish ladders
structures added to a dam that are built like set of stairs with water flowing over them to allow migrating fish to reach their traditional breeding grounds
aqueducts
canals or ditches used to carry water from a location of abundance to a location of need; modern construction includes concrete canals and pressurized steel pipes above or under ground. (PROS: alleviates lack of water; clean; enables persistence of people
desalination
obtaining fresh water by removing the salt from salt water, through distillation or reverse osmosis (currently mainly attempted in Middle East; can be expensive/energy consuming, + brine issue.)
distillation
desalination process where heat is used to boil water which leaves its salts behind as it evaporates; the steam produced is then captured and condensed, yielding pure water
reverse osmosis
desalination process where water is forced through a thin semipermeable membrane at high pressure; water can pass through the memberane but the salts cannot.
furrow irrigation
easy and inexpensive; 65% efficient; farmer digs trenches along the crop rows and fills them with water, which seeps into the ground and provides moisture to plant roots
flood irrigation
more disruptive to vegetation; 70-80% efficient; involves flooding an entire field with water and letting the water soak in evenly
spray irrigation
expensive and energy-consuming; 75-95% efficient; water is pumped from a well into an apparatus that contains a series of spray nozzles that spray water across the field
drip irrigation
reduces weed growth; 95% efficient; uses a slowly dripping hose that is either laid on the ground or buried beneath the soil to water plant roots.
hydroponic agriculture
cultivation of crop plants under greenhouse conditions with their roots immersed in a nutrient-rich solution, but no soil. (PROS: recycles water so is 95% more efficient than traditional irrigation; yields more crops per hectare; because controlled, can g
contaminated water
wastewater from toilets, kitchen sinks, and dishwashers that contain waste/contaminants/bacteria and should be disposed of (sewage treatment plant)
industrial water use
withdrawn and consumed by electricity generation, refining of metals such as copper, aluminum, and steel, and paper
household water use
depends on level of development and consequent appliance/bathroom fixture use; used for purposes (listed from greatest to least consumption) of toilet flushing, bathing, laundry, cooking and drinking
grey water
wastewater from baths, showers, bathroom sinks, washing machines that can be recycled for household uses other than drinking