Geography 210: Physical Geography and Environmental Issues

1. Geography 210: Physical Geography and Environmental Issues Water Supply, Use, and Management

2. This is WATER week Water on Earth Where is it, and in what form? Fresh water on the continents (S&S 15) How does water get (re)cycled? What impacts the availability of usable water? Issues of water management & supply Stream flow and flooding Local water issues Wetlands: form, function, remediation FIELD TRIP FRIDAY!!! Dress appropriately�

3. The USEPA National WetlandsOffice�Its Role in WetlandPolicy and Protection Doreen M. Vetter Special Assistant for Water Office of the Administrator U.S. Environmental Protection Agency Friday October 6, 2006 1:30-2:30 pm Heffner Wetland Building Lobby Olentangy River Wetland Research Park

4. What�s special about H2O? Heat capacity Universal solvent High surface tension Exists in all 3 phases at normal Earth surface temperatures Solid H2O is lighter than the liquid H2O Sunlight penetrates water

5. Global water supply & distribution 97% in oceans 2% in glaciers 1% elsewhere Groundwater Lakes Rivers, streams Atmosphere (0.001%) Abundance is not the problem, delivering enough when it�s needed is.

6. Hydrological Cycle

7. Freshwater vs. saltwater 97.5 % of all water on Earth is saline Remaining 2.5 percent is freshwater ~75% in Antarctic and Greenland ice sheets ~24% as fossil groundwater. Only 0.26% is �accessible� lakes, reservoirs, rivers and streams 0.007% water on Earth is renewable and available for use on a sustainable basis.

8. Water usage: A global perspective Water usage accelerating, globally 1975: 700 km3/y 2002: 6000 km3/y demand for water to sustain, feed, and employ the world's people is projected to double by 2025. Compared to other minerals, water is inexpensive Usage is 1000 x that of all other mineral production Usage is now a significant fraction of that available Usage is on-sustainable in many regions of the world

9. Domestic water use Our society consumes 50-100 gallons per person, per day. This pie chart shows how an average home in Akron, OH uses water (src: USGS).

10. Future water shortage > 50% of humanity will face water shortages within 50 years, UN report, January 2003 "water-stressed" countries US will overuse available surface water resources by 13% in 2020, USWRC $400 billion /year global industry Privatization Water, The Next Oil?

11. Desalinization: A viable option? Removes salt from water Filtration: forcing saline water through salt-impermeable membranes Each m3 of sea water contains 40kg (88 lb) of salt Salinity = 4%. >500 �desal� plants now exist. Cost-prohibitive 10x that of existing water supply in US Requires large amounts of energy. Environmental issue What to do with the very salty water coming out of the desal plant?

12. the hydrologic cycle of water from the oceans and the continents to the atmosphere through evapotranspiration; back to the ocean and continent surfaces through precipitation and eventually returning to the oceans through surface runoff (rivers) after storage (lakes, ground water, ice sheets) Hydrologic cycle

13. Quantifying water supply Water Budget: model balancing inputs & outputs Simple annual budget : (Precipitation � Evaporation � Infiltration = Runoff) Useful in water resource management Supply is NEVER greater than runoff Large year to year variations in precipitation rate & stream flow Even humid regions can have drought

14. US Water Budget

17. Droughts happen That sucks� Loss of land fertility Crop failure Famine Potential Water Resource Management

18. Continental fresh water: location & management issues Ground water Surface water

19. Groundwater & surface water flow system Fig 20.3 Groundwater and surface water flow system.Fig 20.3 Groundwater and surface water flow system.

20. Groundwater Occurs below the water table, where the soil is saturated Aquifer = undergrnd zone where water can be extracted at useful rate Depletion by wells causes drawdown a cone of depression in the water table As many wells exploit an aquifer, their cones of depression merge to create a general lowering of the water table

21. Ground Water Contamination

22. Surface-Groundwater interactions

23. ~1/2 Americans use groundwater as primary drinking water accounts for 20% of US water usage Overdraft: when discharge (output) > recharge (input) Problems: land subsidence, salt water intrusion Groundwater issues

24. The Ogallala Aquifer Composed of water bearing sands and gravel, i.e. groundwater �filled during melt of ice sheet in last ice age. �current 20 x overdraft, -> 1.74 feet per year (1,082,631 acre ft). North Plains Groundwater Conservation District (http://www.npwd.org)

25. Subsidence:Groundwater level changes as a result of pumping in the Texas-Oklahoma High Plains region. Fig 20.7 Groundwater level changes as a result of pumping in the Texas-Oklahoma High Plains region. (Source: U.S. Geological Survey).Fig 20.7 Groundwater level changes as a result of pumping in the Texas-Oklahoma High Plains region. (Source: U.S. Geological Survey).

26. Salt water intrusion Depletion of groundwater causes a cone of depression in the water table and can lead to salt water intrusion if along a coastal site

27. Surface Water the relative magnitude of discharge of major rivers in the United States

28. Sources of stream flow

29. Measuring stream discharge (Q)

30. Hydrograph

31. Urbanization effect

33. Flooding Most universally experienced natural hazard. Floodplain Urbanization and flooding Land use planning

35. Water Use and Management Off-stream use: removed from source, returned Consumptive use: removed, but not returned In-stream use: navigation, hydro power, habitats, recreation Water Resource Management Stream diversions

36. In stream uses

37. Trends in U.S. usage (1950-95)

38. Trends by category Major use: irrigation and thermoelectric Irrigation use leveled by ~1980 Industry use declined after ~1980 Public and rural supply use increased (POPULATION)

39. Irrigation and land use

40. The Aral Sea is drying up and dying as a result of diversion of water for agriculture. Fig 20.9 The Aral Sea is drying up and dying as a result of diversion of water for agriculture (courtesy of Philip P. Micklin).Fig 20.9 The Aral Sea is drying up and dying as a result of diversion of water for agriculture (courtesy of Philip P. Micklin).

42. Water Conservation �is the careful use and protection of water resources. Involves both quality and quantity. Improved agricultural irrigation could reduce w/drawl by 20-30%; how? Price water to encourage conservation Use lined or covered canals to reduce seepage and evaporation

43. Comparison of agricultural practices in 1990 with what they might by by 2020. Fig 20.12 Comparison of agricultural practices in 1990 with what they might by by 2020. The improvements cal for a variety of agricultural procedures, from biological pest control to more efficient application of irrigation water to restoration of water resources and wildlife habitat. (Source: P.H. Gleick, P. Loh, S.V. Gomez, and J. Morrison, California Water 2020, a Sustainable Vision, [Oakland, Calif: Pacific Institute for Studies in Development, Environment and Security, 1995].)Fig 20.12 Comparison of agricultural practices in 1990 with what they might by by 2020. The improvements cal for a variety of agricultural procedures, from biological pest control to more efficient application of irrigation water to restoration of water resources and wildlife habitat. (Source: P.H. Gleick, P. Loh, S.V. Gomez, and J. Morrison, California Water 2020, a Sustainable Vision, [Oakland, Calif: Pacific Institute for Studies in Development, Environment and Security, 1995].)

44. Water Conservation: Domestic Use �only 10% of national water usage Most consumed in bathroom & clothes washing Concentrated urban populations How to conserve? �Xeriscaping� (i.e. no green lawns in AZ!) Don�t flush; more efficient fixtures Fix leaks: 1 drip per second = 15 gals / day

45. Wetlands Important ecologically and aesthetically Defined: areas inundated by water; or where land is saturated to a depth of a few cm a few days/yr Functions: Water (and carbon) storage; groundwater recharge Natural filters (�kidneys�) Highly productive ecosystems (habitats) Flood control

46. Why bother retaining/restoring wetlands? Reduce downstream flooding Purify water Sites of concentrated nutrient cycling Groundwater recharge Nursery grounds for fish, shellfish, birds and other animals 45% of endangered animals depend on wetlands Coastal wetlands form barrier to storm surges Aesthetically pleasing

47. Can wetlands be restored? 1% of US wetlands are lost every 2 yrs; est. 90% of total freshwater lost in 200 yrs Compensatory restoration required by National Environmental Policy Act of 1969 Legal success ? ecological success Self-design as ecosystem property: natural processes contribute to species introduction and selection

48. Dams and the Environment Considerable environmental effects: Loss of land, cultural resources, biology Sediment storage behind dam Downstream changes in hydrology and sediment transport impact river environment and organisms

49. Case study: Dam removal in ME

50. Summary Water enables life Water we can use is a tiny fraction of total on Earth Water supply & usage involves many interactions; a water budget is needed Water consumption will likely increase with population, even as w/drawl decreases slightly Water w/drawl conflicts with in-stream needs Groundwater use and overuse has resulted in problems Water use for agriculture is most significant area for conservation

51. Summary (cont.) Wetlands are important components at the ecosystem level, benefiting people and other ecosystems Flooding is perhaps the most universal hazard in the world, enhanced by urbanization; best approached with land-use planning We are facing a growing water shortage