Conflicts over water – diversion, depletion, degradation

1. Conflicts over water – diversion, depletion, degradation • Introduction: when the ability to use water is diminished – through pollution, reduction in availability, or other harm – conflict usually results. • Three sources of conflict: • Diversion – re-allocation/transfer from one river basin (or aquifer) to another by tunnel, aqueduct, other means. • Depletion– using up available supply without replenishment. • Degradation – diminishing usefulness of water; e.g., through contaminants that cannot be easily removed, changing functioning of a water body.

2. Water diversion as source of conflict • Many early civilizations arose through ability to divert water for agriculture/public supply: e.g., Sumeria (Iraq), China, Egypt, Rome. • Diversion requires administrative as well as engineering skills. • Some (e.g., Karl Wittfogel – 1950s, Donald Worster – 1990s) believe large-scale diversion shaped authoritarian character of ancient societies by: • Imposing centralized planning & control. • Enriching water-dependent elites/aristocrats. • Exploiting workers, encouraging slavery, serfdom. • Suppressing private property.

3. Nile River irrigation - Egypt (c. 2000 B.C.)

4. Roman Aqueduct – Segovia, Spain Built, 1st Century A.D. – still in use today

5. Dujiang Irrigation project – Min River, China Built during Qin dynasty – 256 BC; near Chengdu, Sichuan Province

6. Diversion and California • Urban growth (e.g., San Francisco and Los Angeles) and agriculture (e.g., Imperial Valley) drove demand for long-distance diversions. • California’s experience illustrates impacts: • Water rights - mining, agriculture, urban use led to acquiring of water rights –outright or sometimes secretly – rights became enshrined in law. • Ecological effects – reducing stream flow; introducing “exotic” fish species: • “Return flow” stipulations – e.g., Imperial Valley/Salton Sea. • “Fish screens” – Great Plains; under discussion in N. California (CALFED). • Social & economic effects –reduction of regional income, economic opportunities, quality of life (e.g., Owens Valley).

7. Major diversions of water in California

8. Ecological issues - Salton Sea (formed 1905) • Contemporary problems: • Nutrient inflow from surrounding farming regions (eutrophication). • High salinity due to evaporation & less inflow from Colorado River. • Dust along shoreline where evaporation has occurred. • Annual bird die-offs. 2005 photo

9. Hydraulic gold mining impacts (N. California, 1850s) Placer County, CA – Sierra Nevada mountains

10. Socio-economic issues: Owens Valley • Restoration efforts: • Return flows of 15,000 acre/ft./yr. • “Re-watering” portions of Owens and Mono Lakes, lower Owens River. • Restock sport fisheries – bluegill, bass, trout. • What won’t be restored: • Regional income. • Population. • Lands along valley that can be used for economic development. FROM: LA Department of Water and Power

11. Depletion of supplies – a growing problem • Surface and groundwater supplies can be diminished beyond natural ability to be replenished. • Groundwater examples: • Las Vegas, NV – until 1980s, received 30% of water from aquifers and springs; now 0%; 90% from Colorado River, rest from N. Nevada. • Solution? Leave remaining springs a “natural reserve,” diversify imports, conserve, undertake aquifer recharge.

12. Las Vegas – groundwater management Subsidence and “fissuring’ caused by groundwater drawdown – N. Las Vegas Lorenzi Park, west of downtown Las Vegas – one of last remaining “springs” At the original site of “The Meadows”

13. Mississippi River Embayment Aquifer system • Memphis, TN – draws 160 million gallons/day from aquifer system shared with other states– water levels are dropping; wells becoming deeper/more expensive to drill: • Mississippi claims that 60/160 million g/d of Memphis’ water actually come from “beneath” northern part of their state – residents are losing 20% of their water due to Memphis’ pumping . • February 2010: U.S. Supreme Court refused to overturn appellate court ruling in favor of Memphis: “Mississippi had not shown real or substantial injury.” • If Memphis had lost, would have had to build a treatment plant and draw water from Mississippi River.

14. Memphis, Tennessee

15. Land Subsidence – San Joaquin Valley San Joaquin Geological Survey • Solution? Reduce groundwater pumping; recharge aquifer with surface flow.

16. Evidence of land subsidence in San Joaquin Valley (1925-1977)

17. Degrading riparian “function” • California example – Los Angeles River: • Until early 20th century – source of water supply for farms, orchards – through “zanjas” (ditches) used to move water. • 1930s to 2000s – an urban “flood control” corridor to permit commercial & residential development. • The future (2000 and beyond)?

19. Los Angeles River – modern history Near Griffith Park (c. 1900) Seasonal floods - 1941 Flooding – Arroyo Seco (1913)

20. LA River Today – Glendale area Los Angeles River today

21. Los Angeles River Revitalization Master Plan • City of LA; LADWP, Army Corps of Engineers, public interest groups. Goals: • --Remove channelization along 32 miles of river – from Canoga Park to Vernon. • --Re-plant native vegetation: develop “greenways” & parks. • --Achieve flood abatement, improve water quality, celebrate cultural heritage of river, foster civic pride.

22. Location map – Los Angeles River

23. “Virtual” future –courtesy Los Angeles River Revitalization Master Plan

24. A glimpse into the future? – Los Feliz area

25. Mouth of Los Angeles River – Long Beach Golden Shore Marine Reserve – habitat restoration plan (2006)

26. Benefits of Los Angeles River restoration (LARRMP) • Improved natural environment and a healthy, functioning River • Improved water quality throughout the River Corridor • Significant expansion of City’s open space system • Increased tourism and recreation-related revenues • Creation of new jobs • Increased economic investment and tax revenues

27. Lessons – why we degrade rivers, how we can stop • Changing urban needs influence how we value rivers. • Initial settlement • Industrialization • Post-industrialization • Flood and drought influence perception of their usefulness; prompt us to harness and control them. • Post industrial change makes people find new respect for natural amenities & desirability of rivers as recreational, aesthetic, and community development assets.