Copyright 2011 Gary A. Robbins. All rights reserved.

Transcription

1 Water Potpourri 34% of fresh water used in US is for irrigation Irrigation Copyright 2011 Gary A. Robbins. All rights reserved.

2 How Much Irrigation Water is Needed? Crop related factors Crop type Amount of cultivated land Growing season Climate PPT ET Soil infiltration rate Moisture content Grain size distribution (soil type) Method of irrigation efficiency

3 Flood Irrigation

4 Fixed Spray Irrigation Spray irrigation Water flows through the tube and is shot out by a system of spray-guns Large farms Fixed sprinkler system Mobile sprinkler system (Center pivot or Lateral sprinkler systems) Center Pivot Lateral Sprinkler

5 Drip Irrigation: Water is sent through plastic pipes with holes in them that are either laid along the rows of crops or buried along their rootlines

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7 Desalination Facts 11,000 desalination facilities operate in 120 countries around the world Global capacity of 4 billion gallons per day Most of the capacity is located in the Middle East 60% are located in the Middle East The world's largest plant in Saudi Arabia produces 128 MGD of desalted water 1,200 plants in the U.S 12% of the world's capacity is produced in the Americas, with most of the plants located in the Caribbean and Florida In 1992, the cost to desalinate an acre-foot of water was about $2,000. Today, that cost is less than $800 per acre-foot (0.2 cents per gallon)

8 Desalination Processes Reverse Osmosis Distillation phase separation method where saline water is heated to produce water vapor, which is then condensed to produce freshwater.

9 Reverse Osmosis

10 Waste Removal

11 Wastewater Treatment

12 Primary Treatment Primary treatment involves screening followed by a set of settling tanks that let the water sit so that the solids can settle out Stage 1 Primary screen filters out large particles ( e.g., diapers, paper) Stage 2 --primary treatment might remove half of the solids, organic materials and bacteria from the water Primary Clarifier: settlement tank

13 Secondary Treatment Secondary treatment, removes organic materials and nutrients. Stage 1 the water flows to large, aerated tanks where bacteria consume organic material Tank is aerated to promote aerobic biodegradation Aerobic biodegradation Organic+O 2 CO 2 +H 2 O +bacteria mass Aeration Tank

14 Secondary Treatment Stage 2--the wastewater then flows to settling or trickle tanks where the bacteria settle out. Secondary treatment might remove 90 percent of all solids and organic materials from the wastewater After secondary treatment waste water may be discharged or require more treatment

15 Tertiary Treatment Denitrification and disinfection Denitrification Anaerobic tanks bacteria in absence of oxygen convert Nitrate to Nitrogen gas Disinfection UV Chlorination Discharged, recycled Artificial Recharge

16 Water Use Conflict Resolution

17 Conflicts Usage vs. Environment Consumption vs. Irrigation Bottled Water vs. Public Supply Usage vs. Usage

18 International Conflicts 214 river basins are multinational 2 billion people depend on international cooperation to share water supplies snd maintain water quality

19 Types of Conflicts Wars Personal confrontation ( water rage ) Litigation Changes to allocation law

20 Taming Conflicts Conservation (esp. in irrigation) New technologies for desalination Recycling Use of waste water Reducing pollution Improved water infrastructure in the developing world (wells, sanitation, water treatment) Establish political (national and international) treaties

21 Chattahoochee River Examples Jordan River Basin

22 Economics of Water Use Commodity or Right?

23 Value of Water Commodity as oppose to a right Function of: Demand Supply (space and time dependent) Cost of providing it Quality Quantity Location Water-diamond paradox Water necessary for life but cheap, diamonds not but expensive uhh? All in cost of production!!!

24 Water as Commodity Can be argued that water shortages in part are due to not placing high enough value on it. Under-priced water leads to waste, inefficiency E.g., government subsidized irrigation water from reservoirs.

25 Water Marketing Sale or lease of water rights Transfer of water rights between watersheds Transfer of water between watersheds Auctions of water (farm subsidiaries) In 2001, GA, irrigators were paid not to pump! Water Banking Government run, lease water in time of drought (CA, Az, NV) for storage or supply use Pollution Fees Discharge fees Trade discharge amounts amongst discharges

26 Water as a Right Generally agreed that no human should be denied water if they cannot pay for it Government has responsibility to assure you are provided with water Are you aware of federal law that requires food establisments to provide you with a free glass of water if asked even Starbucks and the movies!! Humans vs animals and plants? Who has more right?

27 Sustainable Development 1.1 billion people do not have access to safe drinking water To change this, requires construction of water delivery infrastructures Costly, government subsidiaries, high costs for water in places that need it the most Conservation Charity is not enough Cholera in Haiti Train people to operate water system

28 Emerging Water Issues

29 Emerging Issues Emerging Contaminants Stormwater Reduction Maintain low flow conditions in streams Water Conflicts Competing usages Limited supply Water as a Commodity Control of resources Bottle vs tap Global Climate Change

30 Global Climate Change Higher T means Increased water demand by crops and people Changes in PPT patterns Some places wetter and some drier US predicted to see increases in PPT

31 Climate Change and Water Resources Management: A Federal Perspective Key Point 1: The best available scientific evidence based on observations from long-term monitoring networks indicates that climate change is occurring, although the effects differ regionally. Key Point 2: Climate change could affect all sectors of water resources management, since it may require changed design and operational assumptions about resource supplies, system demands or performance requirements, and operational constraints. Key Point 3: Climate change is but one of many challenges facing water resource managers. A holistic approach to water resources management includes all significant drivers of change. My Key Point: Think adaptation not just mitigation

32 Technological Advances Dealing with Water Artificial Ground Water Recharge Basins, injection wells Water Conservation How it is used Water saving fixtures Water reuse (gray water) Shipping water

33 Changes to Our Way of Thinking Philosophy of Sustainability Watershed management Water ethics Water education to promote wise use of water Philosophy of Protection Develop and enforce environmental regulations on local level Consider water in planning and zoning