1. Access to Freshwater

2. Human Uses Domestic Agriculture Industry Electricity Transportation
Drinking, washing, cleaning
Agriculture
Irrigation, drinking for animals
10x higher than domestic use!
Industry
Manufacturing, mining, cooling
Electricity
Dam!
Transportation
Ships on lakes and rivers
Boundaries
Rivers and lakes mark boundaries between nation states

3. Water Needs
**The UN now uses the term “water crisis” to refer to our current situation
It isn’t that there isn’t enough water world wide, but that it isn’t evenly distributed!
Up to 40% of humans alive today deal with some level of water scarcity

4. Sustainability of freshwater resource usage
Sustainable use would allow for full natural replacement of the resources exploited and full recovery of the ecosystems affected by their extraction and use
Sources of Freshwater
Surface Water
Rivers, streams, reservoirs, lakes
Aquifers
Groundwater that can be extracted directly from the surface or via wells.

5. During a drought, what will happen to the water table?

6. Aquifers
Aquifer: A layer of porous rock adjacent to a layer of impermeable rock
Only refilled in places where the porous rock is exposed at the surface and infiltration from precipitation
Flow is VERY slow
Some “fossil aquifers” are no longer exposed at the surface and therefore are never recharged

7. 2 types of aquifers Renewable aquifer: (Recharges slowly)
Natural recharge: replenished naturally by precipitation and percolation
Lateral recharge: Recharged from the side by nearby streams and lakes
Nonrenewable aquifer: (fossil)
very little recharge, deep underground (mining)
Formed tens of thousands of years ago
Ex. Ogallala, under the Great Plains

8. Freshwater Issues Climate Change Low water levels in lakes and rivers
Disrupts weather patterns altering water supply
Low water levels in lakes and rivers
Can make navigation impossible affecting economy
Slow water flow
Causes deposition of sediments which fills the streams and eliminates wetlands
Pumping too fast from aquifers
Cone of depression
Pollution
Irrigation degrades soil
Evaporated water leaves dissolved minerals on surface causing salinization
Thermal Pollution
Warm water outflow from power plants affects dissolved oxygen

9. WITHDRAWING GROUNDWATER
Most aquifers are renewable resources unless:
water is removed faster than replenished
If they are contaminated
Groundwater depletion is a growing problem mostly from Irrigation.
Effects of Groundwater Over pumping
Subsidence: Land can sink which can lead to sink holes
Sink Hole
Salt Water Intrusion: When the water table is lowered the normal interface moves inland

10. Possible Solutions Increase Supply Reduce Domestic Use
Reservoirs, desalination plants, rainwater collection, artificially recharge aquifers
Reduce Domestic Use
Low flow toilets, faucets, etc.
Closed system car washes
Grey water recycling
Water from sink could be used in toilet!
Irrigation
Drought resistant crops, efficient irrigation methods
Reduce pesticide/fertilizer use
Treat polluted industrial water
Regulate maximum temperature of cooling water