Water resources

Most abundant, but also most essential of resources. Needed to drink (potable), washing (hygene), energy (hydroelectric), industry.

Distribution very different matter as either too little - drought

too much - floods

Either causes problems

Water Use

Domestic - each person uses minimum 190gals/year just to survive. washing etc extras

Agriculture - irrigation

Industrial

Use in each sector depends on country's economy

Domestic Agric Industry

US 10 40 50

Japan 10 70 20

Ger/UK 20-30 10 60-70

India 5 85-90 5-10

Global distribution of Water

1.36 x 1021 km3 97.2 % in oceans, 2.15% ice caps - but inaccessible

Our requirements met by 0.65% remaining

.001% atmosphere

.0001 rivers streams

.009 % freshwater lakes

.008% saline lakes and inland seas

.005% soil water (vadose)

.31% shallow ground water (less than 1km)

.31% deep ground water

Global precipation

Cycling of water in the Earth : the hydrologic cycle

Water one of the few earth resources that is renewable

Evaporation

Precipitation - rain, snow, hail. Factors effecting precipitation

collection of precipitation

Runnoff rivers streams and lakes -

Factors effecting ratio between runnoff and infiltration

Infiltration - vadose and groundwater zones

Evapotranspiration - roots take up soil moisture and is exhaled through leaves. A large tree may transpire 2 - 300 gals/day!!

Groundwater

Major source of potable water.

Porosity and permeability of rocks.

Aquifers and aquitards

Water table

Phreatic zone, vadose zone

Slope of water table (head) and flow of groundwater (in S florida not

much slope natural flow rates about 1-2m/day)

Springs where water table meets the ground surface - discharge - and lowering of water table

Head and discharge (also permeability)

Lakes and water table level

also rivers

Recharge of water table and seasonal fluctuations

Aquitards(aquicludes) and perched water tables

Wells and water table

Cone of depression of water table around regularly pumped well

Drawdown (in S Florida domestic well few inches; well fields 7-8ft)

Artesian Wells

Florida situation- Floridan aquifer and wells at John Pennekamp and Chekika park

Oases

Contamination of groundwater

Sources of contamination:

human/animal wastes (bacteria); industrial wastes , gas stations, factories etc (toxic wastes)

Flow of groundwater - filtering action, time of flow to discharge point

Limestone (Karst) Aquifers

Solution of limestone; developement of caves

Surface drainage in karst areas - swallow holes and sink holes

Groundwater flow in karst areas - conduit flow in caves

Surface Water

Drainage patterns and drainage basins

divides

Flow in streams and rivers

Stream gauging

Hydrographs

Importance in design of dams etc

Dams

Primary purpose: control of water for domestic/agricultural purposes

Secondary: benefit in some cases - capacity to generate electricity if discharge and head sufficiently great.

Design of dams

Use of water

Usage (withdrawal) and consumption

usage (withdrawal) - quantity physically extracted

consumption – that portioj of withdrawal removed from system – withheld from returning to source

US usage 6130 liters(1620 gallons) per person per day. Household 400 liters (105 gallons). Total usage needed to maintain lifestyle often overlooked.

Drinking water

Treatment:

filtration, "scrubbing", addition of chlorine for disinfectant purposes, fluoridation

Irrigation

To grow crops in areas of low rainfall. Now 42% of US usage - more in west than east due to rainfall patterns (80-90% in India and Mexico). Consumes vast amount of water (due to evaporation)

Industry and mining

85% returned (therefore less consumption than for irrigation). Problem is quality of that water – pollution

Hydroelectric power

Dominates US water usage, but consumes little. In US most of potential developed. Rest of world could develop 7 times present capacity. Problem is often that power isn’t generated where most needed

Desalinization of water

In island and coastal communities desalinization of seawater may make sense, although expensive.

Distillation

Electrodialysis

Reverse Osmosis

Freezing

Disposal of brine an issue as is a contaminant

Saudi Arabia, Curaçao, Catalina Islance (California)

Ownership of water - water law

Eastern US: rule is Riperian Law - right of every landowner to make reasonable use of water. Abundance and scarcities shared equally (nobody upstream can legally take all water for example) Exception municipalities get preferred treatment in time of scarcity (eminent domain)

Western US: rule is Prior appropriation whoever got permission to use water first has first rights to it - ie oldest appropriation honored first. Grew out of 1849 gold rush.

(Los Angeles bought rights to Owen's Valley water in 1900's environmentalists and OV residents say LA is "stealing" their water, but LA sauyst by "prior appropriation" their use is legal)

Groundwater rights

Legal decisions on groundwater more difficult than surface because less obvious. Many early descisions made on assumption of unlimited quantities

Environmental water rights

Increasingly damage to environment of misuse of water recognized. Human needs do not now automatically prevail over natural needs. Endangered Species Act, Wetlands Act have been used to restore

Water supply problems

Drought

Groundwater depletion

Sustained extraction that exceeds recharge will cause a problem. Ogallala aquifer (Miocene gravel) of High Plains depleted by 150,000 wells.

Not just US but a global problem

Ground subsidence

Extraction of water can lower not just water table, but land. New Orleans, Ganges delta (Bangla Desh), Santa Clara Valley(California), Houston-Galveston.

Soil deterioration

salinization and alkalinazation in irrigated arid regions, desertification.

Salt Water Intrusion

Contamination in coastal aquifers. Effect of urbanization - increased drawdown because of use; reduced recharge (infiltration) because of roads, buildings, storm sewers intrusions, etc. Result in "salt water intrusions"

some Florida Water issues

Surface water system in South Florida

Okeechobee and Everglades system; pollution problem in Everglades; Everglades restoration.

Kissimmee River project

Biscayne and Floridan aquifers

Geology of Biscayne aquifer, karstification increases porosity

Hawthorn aquitard

Flow patterns in Biscayne aquifer

Contamination problems

High level of water table; gas stations, dry cleaners, industry all polluters

Municipal land fills west of urban area

Salt water intrusions

Ground subsidence and sinkholes

Central Florida region