August 2014 Environmental Science Ch # 15 WATER MANAGEMENT Water Issues Potable Water Hydrologic Cycle Storage (map) Aquifers/ Aquiclude/ Aquitard/ Artesian Water Human’s Impact on the Hydrologic Cycle. Types of Water Use Domestic , Problems/ Treatment Agricultural, Irrigation/ costs In Stream, Drawbacks Industrial, Clean Water Act 1977,81, 87, 93. Types of and sources of Water Pollution Toxic, Bioaccumulate Decaying Organic Material, Anaerobic Bacteria Nutrients, excessive growth. Sources of Water Pollution- Point vs non-point Municipal , Es cheri chia coli/ Cryptosporidian Agricultural, surface waters/ conservation buffer Industrial Thermal Marine oil pollution. 50% Biodegradable; 20% evaporate; 14% recovered; 12% settles, 3% move shoreward. Ground Water Pollution Sources – Ag products, fuel tanks, septic tanks. Water Use Planning Problems with water Diversion, wild life disruption Waste water Treatment. – Primary, Secondary and Tertiary/Ozone Preserving Scenic Water Areas and Wild life habitats. US Fed Wild life and Scenic Act 1968 Salinization GW Mining Salt water intrusion. Global Prospectives The Everglades/ Aral Sea/ Garden City, Kansas/ the Mediterranean/ Lake Victoria 1 WATER MANAGEMENT 15 – 1. Global Water Challenge Rising Demands Climate Change No subsitutes 15 – 2. The Water Issue Organisms can exist only where there is access to water. Properties – Unique due to its molecules being Di- Polar. It causes other molecules to separate. This makes it a solvent. It also has the ability to store heat. It heats and cools more slowly than other substances. As a result its presence modifies the local climate. 70% of the planet’s surface is covered with water, of which 3% is potable - free of dissolved salt, plant and animal wastes and bacterial contamination. Previously believed to be inexhaustible. UN reports that within this decade, all will experience water shortages, due to: Droughts/ floods Pollution Increasing population demand. 30% of the world’s population does not have access to safe drinking water. 15 – 3. Hydrologic Cycle All the water on earth is locked into a constant recycling process, due to energy movement. Recycling called the Hydrologic cycle. Evaporation – energy added Precipitation as rain, snow or sleet - energy lost Infiltration to the GW table or run-off. Evapo-Transpiration - plant absorption and release Water is stored in glaciers and aquifers naturally. Unconfined aquifers are overlain by aquitards and WT. It is replenished by rain. The Vadose zone/ zone of aeration/unsaturated zone lie above the aquitard. Confined aquifers lie on an aquiclude. Replenished through recharge zones. Artesian wells draw their water from confined aquifers, a function of pressure. 2 15 – 4. Human Influence on the Hydrologic Cycle Major impact -Land use – Irrigation/ Dam construction/ Cooling cause evaporation Urban development affects run off. Timber harvesting decreases evapo-transpiration Cloud seeding causes precipitation. 15 – 5. Kinds of Water Use Water use is measured by the amount of water withdrawn from the source, but not all withdrawn water is consumed. The water that is incorporated into a product or lost to evaporation is considered consumed. Water usage is classified into 4 categories: Domestic – source is private wells in the rural areas, and Purification facilities in cities. 37% of the latter water comes from well. o Uses- as a solvent and drink. Approx. 100 to 140 gals/day/person. o Problems – demands exceed supply. Waste is 4X consumption. o Public attitude is: a limitless resource. Can be corrected by increasing cost. Treatment involves filtering through sand and charcoal to remove particles. chemicals are added to remove dissolved matter. It is disinfected (chlorine) to remove any organisms. Ozone or UV radiation is used to remove any left over organisms Desalinization is an option * Cost is anticipated to increase due to greater population and the cost of cleaning, distribution and education. Agricultural – irrigation. GW supplies 40%, surface 60%. Irrigation makes up 80% of the water consumed in the US. The amount used depends on cost/ crops/ product demand/ technology/ government policy. The types of irrigation varies: o Trickle – directly to roots o Furrow – surface or flood o Spray – overhead o Sub irrigation – under ground pipes, which are also used to drain away water Drawback: Expensive, besides having a major impact on land values. Increase cost will lead to conservation. 3 Industrial use – (accounts for >50% withdrawals in the US), for heat exchange or to dissipate and transport waste. About 20% of the water used in cooling is sea water. In-stream use (water is not removed and there is no consumption. o Hydroelectric power generation (13% of generation in the US). Disadvantages: Construction costs, habitat destruction, nutrients trapped, evaporation, fish migration hindrance, water quality degradation, and shoreline erosion. Advantages: More recreation facilities Navigation (dredging)/Transportation - requires sufficient water depth. Causes pollution. The law prohibits discharge into surface water bodies without permit. Federal Water Pollution Act 1948 provides funds and technical assistance to improve water quality. Clean water Act 1977, 81, 87, & 93. 15 – 6. Kinds and Sources of Water Pollution. Characteristics of Water Pollution. To maintain completely unpolluted water is impossible. Pollution occurs when something changes the natural ecosystem. Pollutants are categorized as: Toxic, which bio-accumulates. Unfit for human use. Decaying organic matter causes major pollution in water because it uses up the oxygen in the water. When O2 is used up, ANAEROBIC bacteria begin to break down waste, produces chemicals responsible for the foul smell and bad taste. BOD is the amount of oxygen required to decay a specific quantity of organic matter. Nutrients are also a pollution problem. Nitrogen and phosphorus compounds, if added to water will increase plant growth and algae. If no growth occurs, these nutrients are limiting factors (in short supply). Excessive growth causes eutrophication. Physical particles alter the clarity of the water. Sources of Water pollution Classified as: Point or non-point sources. Municipal water pollution Storm waters Industrial wastes Homes and commercial wastes: measured through the Es cheri chia Coli and Streptococcus faecalis content. (derived from warm-blooded animals). Detergent content is also a measure of pollution. One end of a soap molecule structure 4 dissolves grease or dirt and the other end is dissolved in water. Farm operations are the primary source of phosphates and Cryptosporidium.. Agricultural Water Pollution Excessive fertilizer and pesticide and Agricultural chemicals pollute surface waters. The use of a conservation buffer lessens the chances of pollution by runoff. Industrial Water Pollution Pollution results from organic matter and or petroleum products, toxic materials, metals, acids, nutrients and particulates. Industries are required to pre-treat waste before sending to the city sewage. Further more, Point Sources are strictly regulated. Mining waste (run off) is a unique source of pollution. Thermal Pollution. Returning hot water to its original source is not allowed, because it changes the habitat conditions in the ecosystem. It can also prevent spawning, or alter the entire food web. Industries use ponds to cool water before return, or use cooling towers, where the hot water is sprayed into the atmosphere and is cooled by evaporation, or use Dry Towers, in which the heated water is pumped through pipes and heat is released into the air. Marine Oil Pollution. Generally, 50% of oil is biodegradable, 20% evaporates, 14% is recovered, 12% settles into the bottom sediments and 3% ends up on the shorelines. There are many sources of pollution, but most result from: Accidents Runoff from streets Improper disposal of oils Intentional disposal of ballast To control pollution, the following steps are normally taken: Recycle or reprocess. Regulations are enforced in refining and shipping operations Ground Water Pollution Sources. Potential sources span every aspect of social, agricultural, and industrial activity. Agricultural products – accidental spills of pesticides, fertilizer applications and irrigation practices. Underground fuel storage tanks Landfills – approximately 90% are not lined to EPA specifications Septic tanks, which are poorly designed, contaminated by nitrate content. Estimate > 20,000,000 are operating with about 30% improperly. Surface impoundments (pits and ponds) >225,000 used. Other possible sources are mining waste, road salt, open dumps, cemeteries, radioactive waste disposal sites, feed lots and urban runoff. 5 15 – 7. Water Use Planning Issues. Metro areas provide three basic services Supply for individual and industrial needs Waste water collection and treatment Storm waters collection and management. Supply is obtained through wells and or surface bodies, which requires watershed protection. Major problems arise when handling storm water runoff. (Most cities must have facilities to store the runoff until treatment is completed). The following must be considered: Increase demand, which will increase pressure for diversion projects. Increase treatment of wastewater or Recycling existing water supply, both of which increase costs. Irrigation water quality, water being returned to source. Groundwater mining Salt water intrusion. Increase demand for water based recreation. Water Diversion, the physical process of transferring water from one area to another. Examples include: Garrison Dam from the Missouri to the Red River. Water moved from the Colorado River to LA. Water moved from Penn. to NY. Problems: Wildlife disruption, falling water level, Fish extinction. Waste water treatment. Primary: Physical - screens used to remove particles, followed by settling in ponds. Secondary: a biological process. Waste mixed with oxygen rich waters, held until degraded by bacteria. Organic matter concentrates as large particles, and settles out as sewage sludge. After dewatering, the waste is sold as fertilizer or sent to a landfill. The discharged water is disinfected by chlorination, or chemically or with ozone or UV light or Ultrasonic energy. Tertiary: Chemicals used to remove dissolved pollutants such as: nitrates and phosphates. The treated water is used to irrigate golf courses, or in wetlands. 6 Salinization – Irrigation Water Quality. An increase in salinity, resulting from salt concentration in the soil after irrigating Example is the Colorado River is 20X more saline after irrigation up stream. Ground water Mining. When water is removed faster than it is replenished, the water table drops and settling occurs. Examples include London, Mexico City, Houston, Las Vegas, San Joaquin Valley, CA. Saltwater intrusion results from GW mining. Example is Galveston. Preserving Scenic water Areas and Wildlife Habitats – Increase demand for recreation. The US Fed Wild and Scenic Act 1968 established a system to protect from development. Historically, wetlands were considered worthless, but recently its value as the breeding ground and spawning areas has been recognized. Wetlands act as filters, slow and prevent flooding and erosion. Global Perspective. Ganges River. Approx 300 Million live in its basin. Water is used to drink, wash, dispose of waste, and bodies are cremated in it. As a consequence of forest destruction, floods occur commonly. There are now health problems, visual pollution, and snapping Turtles are introduced into the Ecosystem. The Everglades. Originally, water drained from N- S. There was a constant flow. Park was established in 1947. Since then land conversion to agriculture and urban development occurred. The introduction of exotic biota and nutrients has cause additional changes. Congress passed a bill to restore it to its natural state at an introductory cost of $1.4 B. Aral Sea. Located between Uzbekistan and Kazakhstan, it was once larger than all of the Great Lakes, except Superior. Water was diverted south to Turkmenistan for cotton production. Since 1960, it has shrunk 75% by volume, 50% of surface area. The fishing industry was destroyed (20 of 24 species are now extinct). Health problems resulted from the dust (exposed beaches) erosion, water supplies are unsafe to drink and the climate has changed. Water is now pumped into the sea. Garden City, Kansas. GW mining from the Ogallala fm. 7 Prior to 1960, wheat was grown. It did not require much water. Corn is now grown and there is an economic boom. Feed lots were established. WT level dropped 4 met. Potential problems include: drop in land values, possibly another dust bowl, Diversion of water. Mediterranean Sea. More than 150 M live along the coastline and 300 M within the basin. The nations have cultural differences and governments. Findings: Hg in mammals up to 300 ppm (should be .05 ppm). PCBs are 50X higher than acceptable limits Pollutants include HC and pesticides. Sea cannot purge itself due to geography quickly. Toxic metals derived from Eastern Europe Some cities have no wastewater treatment. Lake Victoria. Borders Uganda, Kenya and Tanzania. It is the largest fresh water body in Africa. It is now heavily populated with algae, and lilies. Fish population decreased due to over fishing and introduction of exotic species. Nile perch is sold to Israel and European nations. Bottom sediments indicate population growth is a major contributor. 8