1. Water Resources A river runs through it…

2. Water: The Universal Solvent One of the most valuable properties of water is its ability to dissolve. This makes water an excellent solvent. An individual water molecule has a bent shape with a H-O-H bond angle of approximately 105 degrees. Water is polar thus having positive & negative partial charges on its ends.

3. Hydrology: The Study of Water. *The sum of all liquid water resources on Earth is found in the Hydrosphere. The Hydrosphere interacts with the Lithosphere(land), Cryosphere (ice),Biosphere (life), Pedosphere (soil), and Atmosphere(air).

4. How much water is in the hydrosphere? Conventional estimate assumes a total groundwater storage of about 1,700 quadrillion gallons. This gives the estimate of hydrosphere’s total water content as 3.5x10 20 gallons. Oceans (97%) Ice (1.2%) Underground water (0.5%) Surface water (0.02%) Atmospheric moisture (0.001%)

5. Water Distribution:

6. An alternate assumption is that pores in sediments contain about 80,000 quadrillion gallons of groundwater (almost 50 times the conventional estimate). This yields an estimate of about 4x10 20 gallons of water in the entire hydroshere. Oceans (80%) Ground- water (19%) Groundwater (19%) Ice (1%) Surface water (0.002%) Atmosphere (0.001%)

7. Available Water sources 1. Surface runoff – 2/3 lost to floods and not available for human use. Reliable runoff = one third Amount of runoff that we can count on year to year 2. Groundwater Zone of saturation Water table – top of zone of saturation Aquifer – water saturated layers of sand, gravel or bedrock through which groundwater flows. Recharge slow ~ 1 meter per year

8. Use of Water Resources Humans directly or indirectly use about 54% of reliable runoff Withdraw 34% of reliable runoff for: Agriculture – 70% Industry – 20% Domestic – 10% Leave 20% of runoff in streams for human use: transport goods, dilute pollution, sustain fisheries Could use up to 70-90% of the reliable runoff by 2025

9. Freshwater Reservoirs Rivers and Streams Lakes Icecaps Groundwater

10. Much greater in volume than either lakes or streams Non-renewable in our lifetime

11. Groundwater from below the water table seeps into lakes, streams, and swamps and returns to the surface naturally at a spring. Groundwater eventually returns to the ocean, but the trip may take hundreds of years.

12. What is an aquifer? Geologic formation that possesses porosity and permeability

13. Water Table Surface below which pores and fractures of rocks and overburden are water filled

14. An artesian aquifer has groundwater that is under pressure from the water at higher elevations. The pressure will cause the water to rise above the water table in a well drilled into the aquifer, becoming a flowing well if the pressure is sufficiently high.

15. What is a Watershed? An area of land, from ridge top to ridge top, that collects, stores, and releases water to a common point, such as a river or a lake

16. What’s in a Watershed? Streams Rivers Lakes Wetlands Hills Mountains Farms Cities Houses Humans Animals Plants

17. Watershed Functions COLLECT STORE RELEASE

18. Watershed – COLLECT Geology – Mountains, valleys, etc Vegetation – Interception Manmade surfaces

19. Watershed – STORE Wetlands, Lakes, Reservoirs Soil Groundwater Snow and Ice Biology

20. Watershed – RELEASE Streams and Rivers Groundwater Evaporation Human Engineering

23. Hydrological (Water) Cycle Ignoring such long-term effects as the changes in atmospheric storage conditions, run-off filling the ocean basins etc., the hydro-logical cycle is merely the re-cycling of water between land and oceans.

24. Ocean Storage 1,370,000,000 km 3 The Hydrological Cycle Precipitation 285,000 km 3 Evaporation 320,000 km 3 Precipitation 95,000 km 3 Evaporation 60,000 km 3 Run-off 35,000 km 3

25. Evaporation and transpiration Evaporation Stream Infiltration Water table Infiltration Unconfined aquifer Confined aquifer Lake Well requiring a pump Flowing artesian well Runoff Precipitation Confined Recharge Area Aquifer Less permeable material such as clay Confirming permeable rock layer Water Cycle – continuously collected, purified, recycled and distributed

26. Water Cycle: The basic water cycle includes: Evaporation (sometimes transpiration) Condensation Precipitation Surface Runoff Storage (oceans, rocks, groundwater, etc.)

27. Human uses of water: Water is an important but precious resource. It must be carefully managed, and often conserved in order to meet human needs.