D ISTRIBUTION OF W ATER ON E ARTH Chapter 1C - Hydrology Messana Science 8

8.E.1 Understand the hydrosphere and the impact of humans on local systems and the effects of the hydrosphere on humans. 8.E.1.1 Explain the structure of the hydrosphere including: Water distribution on earth Local river basins and water availability

THIRST VIDEO

T HE H YDROSPHERE Hydrosphere: the part of Earth that contains water 97% of Earth’s water is salt water Only 3% is fresh water: ( 30% groundwater, 68% frozen, 2% on surface)

S ALTWATER Oceans cover 71% of Earth’s surface ( about ¾ ) Land takes up 29% of Earth’s surface ( about ¼ ) 2 categories of water in the Hydrosphere…based on Salinity = % salt content Saltwater: 97% of Earth’s water Oceans 35 g salt/kg of water How many oceans are currently recognized today??!!

F RESHWATER Freshwater: < 1 g salt/kg of water ONLY 3% of Earth’s water is fresh 2/3 of that is frozen in glaciers, ice caps, & icebergs (pieces of glaciers floating in ocean) 1/3 of that is liquid & accessible in lakes, ponds, rivers, streams, or underground

F RESHWATER R ESOURCES Most freshwater is frozen at the polar ice caps!! Glaciers are masses of ice and snow that move slowly over the Earth’s surface.

W HERE ’ S THE WATER ?

The Great Lakes are the largest freshwater System on earth. They contain 84% of North America’s surface freshwater and 21% of the world’s surface fresh water supply. Only the polar ice caps contain more fresh water.

W ATER : W HERE D OES I T C OME F ROM ? The Water Cycle

E VAPORATION When water changes from a liquid to a gas (water vapor) What makes the water evaporate?

C ONDENSATION When water changes from a gas (water vapor) to a liquid Give me an example of condensation…

P RECIPITATION When water falls from clouds What are forms of precipitation?

R UN - OFF /A CCUMULATION When water moves from one location to another (run-off) and gathers there (accumulation) What else can the water do?

T RANSPIRATION Water vapor coming from trees and plants

P ERCOLATION /I NFILTRATION Water soaking down into the ground through the soil

WATER CYCLE POP QUIZ Quick!! You have 10 minutes using Play- Doh to construct a model of the water cycle on Earth! – You must include every step of the water cycle – Every student must be able to explain how each step is represented and talk me through the cycle!

W ATER C YCLE – Q UICK R EVIEW 1. Sun heats the water on the surface of Earth  2. Freshwater evaporates into atmosphere as water vapor (salt in ocean stays behind )  3. Water vapor cools & condenses on dust particles to form clouds  4. Water falls back to Earth as precipitation in the form of rain, sleet, snow, or hail  5. Precipitation that hits surface either gets absorbed into ground, stays trapped as standing water, or moves downhill as “run-off” back into lakes, ponds, rivers, streams, oceans **The amount of water on Earth stays the same !!**

F RESHWATER R ESOURCES 1/3 of Earth’s freshwater is groundwater!! Groundwater forms when water moves through soils and sediment and collects in spaces underground. An aquifer is a rock layer that stores water in the spaces between the rock and allows water to flow through it.

W ATER D RAINAGE P ATTERNS Precipitation hits the surface of Earth  1.) If Permeable/Pervious Surface = water will sink in Ex: Sand, Gravel, Dirt 2.) If Impermeable/Impervious Surface = water will not sink in, may be trapped in basin OR may run off from high  low elevation Ex: Red Clay, Cement, Asphalt

W ATER D RAINAGE P ATTERNS Divide = high ridge of land from which water will flow in different directions Watershed/River Drainage Basin = drainage area where all water from one side of a divide flows, all water flows to one central river based on the topography (curves/elevation) of the land What River Basin do we live in?? Catawba River  Wateree River  Santee River  Atlantic Ocean!

E XAMINE A W ATERSHED

P OSSIBLE W ATER F LOW E XAMPLE Precipitation  Land  Flows Downhill  Stream  River  Larger River OR Lake  Estuary = mix of fresh & salt water in a bay  Ocean !!...all water ends up here

G ROUNDWATER Water that seeps into the soil & is pulled down by gravity Can move or sit under the surface if there are spaces between the rock/soil particles (permeable) Water will seep down until it hits an impermeable surface, then fill up from there ( like your bathtub with the drain closed !) The region filled with ground water = Saturation Zone The top surface of this area = Water Table

W ATER T ABLE & S ATURATION Z ONE

A QUIFERS Underground permeable rock or sediment that contains water Particles in ground act like filter to water!!

O GALLALA A QUIFER – UNDER U.S. Huge source of freshwater for drinking & irrigation in the U.S. Depleting at alarming rate… “The average annual depletion rate between 2000 and 2007 was more than twice that during the previous fifty years!”

G ROUNDWATER TO THE S URFACE V IA … 1.) Man-made Well – pipe dug into ground to extract water from aquifer 2.) Artesian Well – water flows naturally to surface because it’s under pressure 3.) Spring – water flows to surface because surface of land dips below water table 4.) Hot Spring/Geyser – water heated up by rocks, pushes up to surface due to pressure

M AN -M ADE W ELL

A RTESIAN W ELL & S PRING

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