Water Resources in NC

What does Water Balance Mean? Precipitation equals Evaporation

Water Cycle Water is constantly moving among the oceans, the atmosphere, the solid Earth, and the biosphere. Link to Water Cycle

Parts of the water cycle Evaporation – water changes into vapor into the air Precipitation – liquid or solid water from the clouds Infiltration – water moving through the ground Transpiration – water released from plants Runoff – when flash rain storm hits the ground and is not absorbed.

Water Facts of Life There is the same amount of water on Earth as there was when the Earth was formed. The water from your faucet could contain molecules that dinosaurs drank. 75% of the human brain is water and 75% of a living tree is water. A person can live about a month without food, but only about a week without water. The average total home water use for each person in the U.S. is about 50 gallons a day. Water expands by 9% when it freezes. Frozen water (ice) is lighter than water, which is why ice floats in water.

Water Supply in the World

Distribution of the Water on Earth 71% of Earth is water 97% in the oceans 3% is freshwater 2% in ice and glaciers 0.6% in underground water 0.4% in rivers, streams, lakes and atmosphere

Water Supply & Use http://ga.water.usgs.gov/edu/waterdistribution.html

How is water used? 70% - Irrigation 20% - Industry 10% - Cities & Residence

Oceans currents

Ocean circulation also influences climate Ocean circulation: ocean water exchanges heat in the water with the atmosphere Thermohaline circulation: a worldwide current system in the ocean. Warmer, fresher water moves along the surface and carries heat to Europe North American Deep Water (NADW): the deep portion of the thermohaline circulation denser, saltier, cool water that sinks moves deep beneath the surface

NADW is vulnerable If Greenland’s ice melts, freshwater runoff would dilute surface waters, making them less dense, and stopping NADW. – This has occurred in the past

Ocean Currents Primary Forces--start the water moving Solar Heating Winds Gravity Coriolis Secondary Forces--influence where the currents flow

Warm and Cold Currents Warm ocean currents: warm water from tropics to poles. Cold ocean currents: cold water poles toward the equator. The Gulf Stream, is a warm-water current that moves up the Eastern coast of the United States

Fresh Water supply

Water Facts The primary use for fresh water in U.S. is for agriculture. In our homes, we use the most fresh water to wash, clean and flush. The typical person in an industrialized nation uses 700- 1000 gallons per week!

Groundwater

Groundwater 50% of the water used by the public is pulled from groundwater Most people who live in the county use groundwater Groundwater link

Movement of water underground Porosity: percentage of pore spaces showing how much water is stored Permeability: water can pass through connected pore spaces Clay: smallest amount of pore space of any soil type – not permeable

Groundwater Zone of aeration: area above the water table where water passes through The water table: the upper level of the Zone of Saturation Zone of saturation: area where the soil, sediments and rock are saturated with water. Groundwater: the water within the Zone of Saturation

Ground Water Aquifer : underground layer of water-bearing permeable rock (gravel, sand or silt) from which ground water can be extracted using a well. A cone of depression occurs in an aquifer when a lot of ground water is pumped from a well.

Artesian well: groundwater rises on its own under pressure Pumping can cause the water table to be lower

Problems with Groundwater Withdrawing water for agriculture Heavy metals contaminating the water (arsenic, cadmium, lead) Salt water intrusion (salt water from ocean enters the groundwater)

Caverns Sinkholes form near the surface causing depressions A cavern is a naturally formed underground chamber when water is withdrawn leaving it empty. Erosion forms most caverns at or below the water table Sinkholes form near the surface causing depressions Watershed Link

Rivers

A stream’s profile Headwater (mountains) Mouth (oceans) at the beginning of a stream Temperatures are cooler Higher Dissolved Oxygen Fish found: trout Mouth (oceans) at the end of a stream Murky waters Lower Dissolved Oxygen Fish found: catfish and carp

Watershed An area of land that contains a common set of streams and rivers Tributary: a stream that empties into another stream

Drainage Basins A drainage basin is the land area that contributes water to a stream

Base level Meandering Stream Temporary or local base levels Lowest point to which a stream can erode Ultimate base level is sea level Temporary or local base levels lakes main streams Meandering Stream Slow moving stream located in the flat regions or territory

Erosion Problems and Flooding

Three ways streams erode channels Abrasion Grinding Dissolving soluble material

Controlling Floods Natural levee parallels a stream and helps to contain its waters, except during flood stage

Controlling Floods Artificial Levees Concrete mounds are built on the banks of a river, increasing the amount of water it can hold.

Results of Floods Floodplains – areas where water floods the land Provides a supplement of nutrient-rich silt to floodplain areas Recharge groundwater Kill and causes property damage

Human activities causing Flooding removing vegetation logging overgrazing forest fires mining destruction of wetlands building on floodplains urbanization

Drought

41% of people live in river basins that do not have enough fresh water! Dry climate Drought Too many people using and wasting water Lack of money to drill deep wells and build storage

Causes of a Decrease in Available Water Dry climate Drought - a period in which precipitation is much lower and evaporation is much higher Desiccation - drying of soil because of such activities as deforestation and overgrazing Water stress - low per capita availability of water caused by overpopulation