The Hydrosphere The body of water, present as ice, liquid water or water vapour.

Watery Planet 71 % of earth covered in H 2 O All organisms made of water – – Trees 60% by weight – – Animals % by weight “Water, water everywhere, nor any drop to drink.” Salt water: 97.4 % Fresh Water: 2.6% Glaciers & Ice Caps: 1.98% Atmosphere: 0.001% Lakes & Rivers: % Ground Water: 0.59% Biosphere: % Soil: 0.005% ≤ 1% considered directly usable by humans Or ~0.007% of all water on earth

Properties of Water Strong forces of attraction (Hydrogen Bonds) – – Major factor in determining waters properties Exists as liquid over a wide temp range – – High boiling (100C/212F) and low freezing (0C/32 F) means water remains liquid in most environments High heat capacity (changes temp slowly) – – Keeps homeostasis in organisms/regulates climate/used as coolant Evaporating liquid takes in large amounts of heat – – Helps disperse heat/effective cooling process (why you sweat)

Properties of Water Continued: Universal Solvent Can Break down (ionize) into hydrogen (H+) and hydroxide (OH-) – – Helps maintain balanced pH High surface tension and capillary action (trees) Unlike most liquids; water expands when freezing – – Lakes do not freeze bottom up; can cause landslides/slumps

Hydrologic Cycle The cyclical movement of water from oceans to atmosphere powered by Earth’s external heat engine (sun) Precipitation – atmospheric water vapor condenses into tiny droplets forming clouds and eventually falls as rain/snow/sleet/hail Evaporation – liquid water to atmospheric water vapor Transpiration – evaporation from biosphere -trees – send more 66,000 cubic kilometers of water vapor into the atmosphere every year (17,000 trillion gallons) Interception – precipitation that does not reach soil

Hydrologic Cycle Continued Infiltration – precipitation that soaks into ground. Part will evaporate again, another part will move into biosphere, most will become groundwater. – – Groundwater flows very slowly but will eventually return to the surface at springs then flow back to ocean.

Hydrologic Cycle Continued Run off – all precipitation that flows over the land, including streams and fraction that temporarily infiltrates near- surface rock.

Precipitation VS Run off In areas of low precipitation only a small fraction of rain ends up as runoff; most evaporates or infiltrates into ground 1/3 is considered ‘Reliable Runoff’ and can generally be counted as stable source of water

Rivers and streams carry much of the run off. – – millions of smaller and medium sized streams carry ½ while 70 major rivers carry the other ½ The Amazon River carries ½ of the ½ (10x more than the Mississippi which is only 2/3 of US )

Crazy pictures you get searching for “Map of Amazon River Basin”……. She loves the pink dolphin

Groundwater 101 Groundwater formed from recent atmospheric precipitation is known as meteoric water – – Greek meteoron (phenomenon in the sky) gave us ‘meteorology’ Equals about 29% of all fresh water in lakes, rivers, glaciers, polar ice caps and Atmosphere. Has been a source for humans for 1000’s of years through digging wells or through springs

Groundwater 101 Groundwater infiltration depends on porosity of soils (how much water it can hold) – – Sedimentary rocks average 5-15 % – – Metamorphic and igneous rocks have very little pore space; mostly fractures Groundwater flow depends on soils permeability – – The capacity of a solid to allow fluids to pass through Generally permeability increases as porosity increases; but permeability also depends on size of pores, connections, and path resistance

Groundwater 101 Drillers need to consider both A good groundwater reservoir has both high porosity (hold large amounts of water) and high permeability (can recharge and be pumped out easily) Places with low permeability will be slow to pump

Groundwater Table Unsaturated zone (vadose zone) Saturated zone (phreatic zone) Boundary between is called Water Table Recharge/Discharge – – The speed water moves strongly affects the balance re/discharge

Aquifers Aquifers Any underground storage of water: Two Types: Unconfined Aquifer; level of water table and below; impermeable rock as a basement and can lose water to the surface Confined aquifer - bound above and below by impermeable beds (such as shale & Clay) – – The relatively impermeable areas are called aquicludes

Artesian Flow Water moving through a confined aquifer is under pressure Drilling a well into a confined aquifer at a point where the elevation of the ground surface is LOWER than that of the water table in the recharge area will allow water to freely flow upward (due to pressure)

Aquifers Continued Can be replenished by natural recharge (precipitation) or by lateral recharge from nearby streams Gravity plays major roll; water will go down (only a meter or so per year) and by pumping groundwater we could dry up local rivers and lower the ground surface (subsidence). Excessive pumping of groundwater in Antelope Valley, CA led to fissures and sink like depressions: 1991

San Joaquin Valley, CA Subsidence - the gradual caving in or sinking of an area of land This area of the San Joaquin Valley has had a 30 foot drop in land height.

Mexico City

Salt Water Intrusion DO NOT CONFUSE THIS WITH SOIL SALINIZATION!!! Intrusion in the movement of ocean water into an aquifer Caused by 1. 1.Sea Level Rise 2. 2.Extensive pumping of the aquifer

Issues with Underground Storage Tanks (USTs) when they become Leaking Underground Storage Tanks (LUSTs)

Answer the following 1. 1.If global warming caused evaporation from the oceans to increase greatly, how would the hydrologic cycle of today be altered? 2. 2.How might the hydrologic cycle have been different 18,000 years ago during the Wisconsin Glacial Maximum, when much of North America, Europe, and Asia were covered with ice. 3.Why does the salinity of seawater remains relatively constant over time? 4.Why are more and more communities in cold climates restricting the use of salt to melt snow and ice on highways? 5.Why would you recommend against extensive development and urbanization of the recharge area of an aquifer that serves your community? 6.Why should communities ensure that septic tanks are maintained in good condition?