Environmental Sciences Course Water resources and pollution Dr. - Eng. Hasan Hamouda

1. EnvironmentalSciences CourseWater resources and pollution Dr.-Eng. Hasan Hamouda

2. Outline Hydrologic Cycle Water Compartments Water Availability Freshwater Shortages Increasing Water Supplies Water Management and Conservation Water Pollution Water Quality Today Water Pollution Control Water Legislation University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

3. WATER RESOURCES Hydrologic Cycle - Describes the circulation of water as it: - Evaporates from land, water, and organisms. (Transpires from plants) - Enters the atmosphere. - Condenses and precipitates back to the earth’s surfaces. - Moves underground by infiltration or overland into rivers, lakes and seas. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

4. Mean Annual Precipitation University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

5. Water Distribution University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

6. MAJOR WATER COMPARTMENTS Groundwater Second largest reservoir of fresh water. - Infiltration - Process of water percolating through the soil and into fractures and permeable rocks. - Zone of Aeration - Upper soil layers that hold both air and water. - Zone of Saturation - Lower soil layers where all spaces are filled with water. Water Table - Top of Zone of Sat. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

7. Groundwater University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

8. Groundwater Aquifers - Porous layers of sand, gravel, or rock lying below the water table. - Artesian - Pressurized aquifer intersects the surface. (Water flows without pumping) Recharge Zone - Area where water infiltrates into an aquifer. - Recharge rate is often very slow. Presently, groundwater is being removed faster than it can be replenished in many areas. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

9. Major Water Compartments Rivers and Streams - Precipitation that does not evaporate or infiltrate into the ground runs off the surface, back toward the sea. - Best measure of water volume carried by a river is discharge. - The amount of water that passes a fixed point in a given amount of time. Usually expressed as cubic feet or meter per second. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

10. Major Water Compartments Wetlands - Play a vital role in hydrologic cycle. - Lush plant growth stabilizes soil and retards surface runoff, allowing more aquifer infiltration. - Disturbance reduces natural water absorbing capacity, resulting in floods and erosion in wet periods, and less water flow the rest of the year. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

11. Major Water Compartments The Atmosphere - Among the smallest water reservoirs. - Contains 0.001% of total water supply. - Has most rapid turnover rate. - Provides mechanism for distributing fresh water over landmasses and replenishing terrestrial reservoirs. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

12. WATER AVAILABILITY & USE Renewable Water Supplies - Made up of surface runoff and infiltration into accessible freshwater aquifers. Water-Rich ad Water-Poor Countries - Water availability usually measured in per capita terms. - Highest per capita generally found in countries with moist climates and low population densities. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

13. Water Use - Withdrawal - Total amount of water taken from a source. - Consumption - Fraction of withdrawn water made unavailable for other purposes (Not returned to its source). - Degradation - Change in water quality due to contamination making it is unsuitable for desired use. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

14. Quantities of Water Used Water use has been increasing twice as fast as population growth over past century. - Worldwide, agriculture claims about 70% of total water withdrawal. - In many developing countries, agricultural water use is extremely inefficient and highly consumptive. - Worldwide, industry accounts for about 25% of all water use. Cooling water for power plants is single largest industrial use. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

15. Water Withdrawal University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

16. FRESHWATER SHORTAGES - Estimated 1.1 billion people lack access to an adequate supply of drinking water. - 2.4 billion lack acceptable sanitation. - A country where consumption exceeds more than 20% of available, renewable supply is considered vulnerable to water stress. - Globally, water supplies are abundant, but, along with capital resources, are unevenly distributed. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

17. A Precious Resource - Currently, 45 countries, most in Africa or Middle East, cannot meet the minimum essential water requirements of their citizens. - More than two-thirds of world’s households retrieve water from outside the home. - Availability does not automatically equate to affordability. Sanitation levels decline when water is expensive. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

18. Depleting Groundwater Groundwater is the source of nearly 40% of fresh water in the US. - On a local level, withdrawing water faster than it can be replenished leads to a cone of depression in the water table, - On a broader scale, heavy pumping can deplete an aquifer. - Mining non-renewable resource. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

19. Depleting Groundwater University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

20. Depleting Groundwater • Withdrawing large amounts of groundwater in a small area causes porous formations to collapse, resulting in subsidence. - Sinkholes form when an underground channel or cavern collapses. - Saltwater intrusion can occur along coastlines where overuse of freshwater reservoirs draws the water table low enough to allow saltwater to intrude. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

21. INCREASING WATERSUPPLIES - Seeding Clouds - Condensation Nuclei - Towing Icebergs - Cost - Desalination - Most common methods are distillation and reverse osmosis. - Three to four times more expensive than most other sources. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

22. Increasing Water Supplies Dams, Reservoirs, and Canals - Trap excess water in areas of excess and transfer it to areas of deficit. - Environmental Costs - Upsets natural balance of water systems. - Ecosystem Losses - Loss of wildlife habitat. Reservoir Size Water Quality University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

23. Dams, Reservoirs & Canals - Displacement of People Three Gorges Dams in China will force relocation of over a million people. - Evaporation, Leakage, Siltation - Evaporative losses from Lake Mead and Lake Powell on the Colorado River is about 1km3 per year (264 billion gallons). - Dams slow water flow, allowing silt (nutrients) to drop out. - Loss of Free-Flowing Rivers University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

24. WATER MANAGEMENT & CONSERVATION Watershed Management Watershed - All the land drained by a stream or river. - Retaining vegetation and ground cover helps retard rainwater and lessens downstream flooding. - Additionally, retaining crop residue on fields reduces flooding and minimizing plowing and forest cutting on steep slopes protects watersheds. University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda

25. Domestic Conservation - Estimates suggest many societies could save as much as half of current domestic water usage without great sacrifice or serious change in lifestyle. - Largest domestic use is toilet flushing. Small volume of waste in large volume of water. - Significant amounts of water can be reclaimed and recycled. - Purified sewage effluent University Of Palestine International ENVI005 Dr.-Eng. Hasan Hamouda