Chapter 9 - WaterChapter 9 - Water

Water Cycle

Water Budget

The World’s Water• Oceans, lakes, rivers,

groundwater, atmosphere, living things, glaciers, and more…

• Water is measured by volume. “How much space it takes up.”

• 97 % is in the oceans

The World’s Water• Less than 3% is fresh!!!

–2/3 is frozen in ice caps

–Rest is fresh (usable) water

–Works out to be less than 1/2 of 1%

OCEANS 97.2%

ICE CAPS 2%

GROUNDWATER 0.78%

LAKES 0.013%SOIL 0.006%

ATMOSPHERE 0.0007%RUNNING 0.0002%

BIOSPHERE 0.0001%

Where is the fresh water?Where is the fresh water?

• TinyTiny part is flowing on the surface of Earth (rivers, streams)

• 100 times that is stored in lakes, swamps, etc.

• 50 times that is stored in the ground as groundwater.

Water CycleWater Cycle• Again like all matter, water is

recycled.

• Simple water cycle (Magnificent 7):Evaporation-liquid to gas Transpiration-liquid to gas in plants

Sublimation-solid to gas

Water CycleWater CycleCondensation–Gas to liquid-clouds

Precipitation-gas to liquid/solid

Runoff-running water on surface

Groundwater-soil moisture, water underground

Water BudgetWater Budget•Compares the input (water you get) and output (water you use) of water in a specific region.

Water BudgetWater Budget• Controlled by many different

climate climate factors

–Air temperature

–Humidity (Season Extremes)

–Rainfall amount

–Soil Type

Water Budget Graphs• A comparison between

Moisture supply (precip) and Moisture demand (evap)

• A water budget has 4 parts: usage, recharge, surplus,

and deficit

Water Budget Graphs• Usage – When plants,

humans, sun is taking water out of the system.

• Recharge - When the ground water is being filled back up

Water Budget GraphsWater Budget Graphs• Surplus - Rainfall is greater than

the need. Soil is moist.

• Deficit - Need for moisture is greater than the rainfall coming into the system. Soil is dry

Rocks Holding Water??Rocks Holding Water??

Porosity – Volume of space in between rocks/soil that can hold water

Permeability – The rate at which water can pass through the pore spaces of rock/soil

Rocks Holding Water??Rocks Holding Water??

Rocks Holding Water??Rocks Holding Water??

• Impermeable – Water cannot pass through the pore space.

• Capillary – Ability of water to “stick” to its surroundings by its surface tension

Rocks Holding Water??Rocks Holding Water??

Water TableWater Table

Water TableWater Table• Ground becomes saturated with

water. This is the ground water that we have been talking about.

• Water Table – The top portion of the “zone of groundwater saturation”

Water TableWater Table• Zone of Aeration – Water and

air mixed with the rocks and soil• Capillary fringe – Border

between air/water and just water. Right above the water table (pg. 154)

• Zone of Saturation – Just water in the soil and no air

Wells and SpringsWells and Springs• Ordinary well - A hole dug or

drilled down below the water table. ( water must be pumped out)

• Spring - Place where the water table is at the surface.

• Artesian well - A well that is pressurized. (water will not have to be pumped out)

AquifersAquifers• Are permeable materials that contain and

carry groundwater–Best are - Sand, gravel, and porous

sandstone

Link to Page About Water Resources