Introduction to Ecosystem Science's homework
Qeeeeee
water.pptxWater: H₂O
ECS 111
6 September 2016
Donald B. Olson
Problems with Water:
Demise of the Marsh Arabs
What sets the scales for water as a commodity?
What sets the price of water?
How does water quality enter the picture?
Is there a need to protect the price of water for some specific uses?
Does the last question suggest that waters has different worth under free trade?
When does water lead to diplomatic problems including war?
National Geo. Apr. 2010
Water in our Ecosystems: Cont.
Adequate water: Domestic, industrial, agricultural uses, and the rest of nature
Sustainability of water supplies: Future use
Maintenance of water quality: Pollution from natural (salt), industrial/agriculture, domestic sources.
Trans-boundary issues: Sharing water between cities/rural districts, states, countries.
Natural Saline Waters
Colorado River
Sources of fresh water:
Ground water: Aquifers
- Volume (km³), removal rate (km³/sec)
– Issue recharge rates and depletion times
Rivers and streams: Runoff in channels
- Volume transport (km³/sec)
- Downstream water quality
Lakes: Still waters, natural and dam created
- Volume exchange: Residence times
- Water quality and pollution build up
Residence and depletion times:
Residence time:TR Equilibrium (Steady State)
Depletion rates:TD
Rate of resource decay
Problems to consider:
Calculate the residence times for the different water pools in the last lecture (see Tables).
Discuss the assumptions you have to make to turn these global numbers into something that might be useful for policy. (What do you have to assume?)
Choose a lake that you are interested in and work out its water balance.
Calculate a depletion time for an aquifer.
Water Stocks in the Environment
21
From: Chow, Maidment and Mays, Applied Hydrology, McGraw Hill, 1988
Water Fluxes in the Environment
Salinity ~ 35 gm salt/kg sea water; potable water < 19
22
More on freshwater availability
23
Global Water Balance (land)
Rainfall (119,000 km3/yr or 31 in) =
Evapotranspiration (72,000 km3/yr or 19 in) +
Runoff (44,700 km3/yr or 11.7 in) +
Infiltration (2,200 km3/yr or 0.3 in)
Conclusion: the world lives on a “water budget”
24
Stocks and Fluxes
Budgeting of an environmental stock takes place over a period of time (day, month, year, etc).
[Change in Stock] = [Flux In]
- [Flux Out]
+ [Stock created]
- [Stock withdrawn]
25
Rainfall Data
Annual Rainfall in the Continental US, 1895-2003
Source: NOAA (www.noaa.gov)
26
Evaporation
Found by “evaporation pans”
Actual Evaporation =
Pan Evaporation x 0.70
27
Transpiration
Vegetation uptake and release of water for metabolic (growth) purposes
Uptake takes place through the roots
Release takes place through the leaves (stomata)
Vegetation functions as a “pass-through” for water
28
Source: Laio et al., Advances
In Water Resources 24, p. 708,
2001
“Evapotranspiration”
Source: Hanson, U.S. Geological
Survey Water-Supply Paper 2375,
1991
29
Water Budget
So, we have water depth D:
D = R – (Q + E + T + I)
This budget must be made over a defined time period (year, season, month, day)
R=rain rate; Q = run off; E=evaporation; T=transpiration; I= infiltration
30
Ogallala Aqufer
A tragedy in the attempts to provide clean water.
The other SE Asian River: The Mekong
Wars and Water:
6-day war 1987 Israel’s big gain
Syria and Turkey
The future of the Dead Sea
Water and Middle East Peace
National Geographic April 2009
NYT 2 February 2014
Miami Herald 2 Feb 2014
Water and Geography
High Corruption and Intrigue Hollywood Style
Can we design a river basin?
What is the best design for a river?
Consider the factors:
- Control of flow
- Water quality
- Safe navigation
Who should govern these?
- States and local government
- National and international issues
Rivers are lost?
Impacts on land use and fisheries
Movement of societies to the coast.
Pollution impacts
Changes in water flows
NYT 24 August 2014
Apalachicola-Chattahoochee-Flint River system of Georgia, Alabama and Florida
A. Ripley (2006) Why We Don’t Prepare, Time, Aug. 28, 2006
What about Lakes?
International Lake Basin Managemnent (ILBM)
Lake attributes:
Lakes studied to date by program
The idea of a case study:
Pick representative ecosystems and do intensive studies.
Use modeling tools to address the ecological relationships.
Link the systems to larger scale biome and climate issues.
Use the study to address management in other similar ecosystems.
