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Freshwater Resources. “The wars of the 21 st century will be fought over water” Ismail Serageldin. Freshwater is the most limited of the Earth’s water resources, at just 2.5% Freshwater systems include:. Rivers and Streams. Wetlands. Lakes and Ponds. Groundwater. Watersheds.
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“The wars of the 21st century will be fought over water” Ismail Serageldin
Freshwater is the most limited of the Earth’s water resources, at just 2.5% Freshwater systems include:
Water use differs depending on the country or region of the world.
Domestic use water used for drinking, air conditioning, washing clothes and dishes, flushing toilets, and watering lawns. The major problem is the maintenance of an adequate and suitable supply of water for growing metropolitan areas. Another problem involves the cost of treating wastewater. A lot of domestic water is wasted through leaking pipes and water mains.
Agricultural use principally for irrigation. However, some of this water is used very inefficiently (e.g., lots of evaporation of water in arid regions resulting in increased salination and desertification).
Industrial Use involves the use of water for cooling, and for the dissipation and transport of waste. Notice that in the U.S., the largest percent of our water is used for industry.
Drought the result of natural or human-induced events (sometimes both). A drought is rainfall that is 70% below average. When rainfall is inadequate, water tables in underground aquifers can drop. Droughts cause multiple problems: adverse effects on crops & livestock, water shortages for people, & water shortages for industry.
Excessive use Excessive ground water and surface water withdrawals especially if not replaced causes multiple problems (see above, extinctions of some species, salt water filling up aquifers, and sinkholes). Low-water conditions exist each year. Consequently, the threat of sea-water intrusion will recur with equal or greater severity as water demands increase, unless additional water is supplied to south Dade County.
Dams • Dams and reservoirs for human water consumption and for generating electricity have immense impacts fish and other wildlife. They also degrade recreational areas.
Sustainability Because water use at its current rate cannot continue, water conservation is necessary. Possible methods: lining open dirt-lined ditches used to deliver water to crops with concrete or plastic, using pipes, drip irrigation instead of sprinklers (where feasible), irrigating early in the morning or at night, change in government policies, and increase the organic content of the soil. Citizens could install also new pipes that do not leak in cities and use conservation practices.
How??? Restoration of watersheds and wetlands (e.g. replanting vegetation) could help. Conservation efforts need to be coupled with population stabilization. Municipal uses could be decreased by low flow faucets, more efficient washing machines and dishwashers, reducing showers reducing toilet flushing at home and fixing leaks. Desalination or desalinization involves the removal of salt from marine water. It works but it is very expensive. Reduction of water use for agriculture by lining irrigation canals, limiting runoff, and using efficient systems.
Water Pollution any physical or chemical change in water adversely affecting organisms, originating from both natural & anthropogenic sources [either point (from discrete locations) or nonpoint (from diffuse areas)
Industrial wastes are often toxic. Newer factories are usually equipped with waste water treatment facilities, older factories still discharge various wastes into the municipal water systems or they discharge directly into a stream or other body of water.
Thermal pollution involves the discharge of cold or heated water (latter used for cooling) into the environment. A nuclear power plant would produce thermal pollution.
Nutrient pollution includes organic nutrients (from sewers, feedlots etc which facilitate the growth of bacteria) & inorganic nutrients (e.g., N, P, Fe, S, Na, & K which facilitate the growth of aquatic plants; see figure 15.19 or 15.20
Question- So if the Clean Water Act was successful why change it? There are ongoing attempts to weaken the EPA and the Clean Water Act. See the links to the reading materials in your notes.
OTHER PROBLEMS WITH WATER
Infectious organisms can contaminate freshwater sources. Poorly treated or untreated water, runoff from feedlots with cattle or other animals, and a general lack of hygiene or sanitary methods result in the presence of disease causing organisms in water used for consumption, washing dishes etc. This is one of the biggest problems involving water in many parts of the world.
Sediment destroys spawning and feeding grounds for fish, impairs the growth of aquatic plants, and speeds up natural succession.
Wastewater is water that has been used in some way and thus could be contaminated in various ways. Thus, this water needs to undergo treatment before use. Water treatment plants use chemicals and filters to provide safe water to people within their municipalities.
Ground water and other parts of watersheds can also be polluted by toxic waste, nutrients, infectious organisms etc.
Of course prevention of pollution is better than cleaning up. Options include: • industries could “clean up” effluents before their release • regulations that prohibit dangerous levels forcing industry to be responsible for prevention • regulations regarding placement of industrial and agricultural areas where pollution of water is likely 4. others?
People who draw their water from wells should insure that their water is safe since it is not treated. For example, in Whatcom County there are areas where the nitrate levels are beyond safe levels and the people who live there use bottled water for drinking, washing dishes etc.
Healthy marine ecosystems are also necessary for humans and other organisms. Oceans and seas are home to a great deal of biodiversity (see figures 16.10-16.13 for 07; 16.9-16.12 for 08) Moreover, the phytoplankton (photosynthetic protists) are the primary producers of this environment and their presence is necessary for the other organisms of these marine environments.
As with the terrestrial and freshwater environments humans use and impact marine ecosystems. • We use these waters for transporting many materials via ships. • We drill for oil and extract other minerals offshore. • We also enjoy these ecosystems for recreational purposes
Unfortunately we also have negative effects on these ecosystems. The pollution of oceans is a major problem. Pollutants include Garbage that has been dumped in the oceans. Medical waste is included as well as plastics that harm ocean life. Old nets also endanger wildlife Oil spills from ships such as the Exxon Valdez. These spills have major negative impacts on the wildlife Excess nutrients that cause dangerous algal blooms like red tides (these result in paralytic shellfish poisoning when people eat contaminated shellfish)
An enormous island of trash twice the size of Texas is floating in the Pacific Ocean somewhere between San Francisco and Hawaii.The California Coastal Commission in San Francisco said the so-called Great Pacific Garbage Patch, has been growing a brisk rate since the 1950s
We also over-harvest the fish and other food animals from the ocean. Many of the fisheries are in great danger of crashing. As we remove more and more of these organisms and as local populations begin to become extinct, we will possibly see entire ecosystems changing or maybe even collapsing. Sustainable fishing as well as other uses of the marine ecosystems is necessary for the continued health of these areas. In fact, the loss of coral reefs, phytoplankton etc. could cause major world wide catastrophes. This is one of the reasons that most scientists are concerned about over-harvesting, pollution, and global climate change.
