Unit V Earth Systems Resources Water Resources Properties

Unit V Earth Systems & Resources

Water Resources • Properties of Water – 2 parts Hydrogen and 1 part Oxygen (H 2 O) – Water is never completely pure in nature. • Many substances water dissolves and causes water pollution • Contents of Sea Water

Hydrologic Cycle • The same water has been recycled through the atmosphere since the earth’s beginning! • Evaporation – conversion of water into water vapor • Condensation – conversion of water vapor into water • Precipitation – water that falls to the Earth from the atmosphere

Hydrologic Cycle • Transpiration – water loss by a plant through evaporation • Respiration/Perspiration – water loss by animals A drop of water could spend as little as 9 days in the atmosphere or as much as 40, 000 years in the ocean before being recycled.

Distribution of Water • Ocean Water – 97. 5% of planet’s water • Cover 75% of the planet’s surface • Freshwater – Remaining 3% divided between rivers, lakes, groundwater, aquifers – greatest amount is in glaciers and polar ice – only ~0. 5% is available freshwater

Water Terminolgy • Surface Water – Precipitation that remains on the surface • Runoff – Movement of surface water to lakes, rivers, etc. • Watershed (drainage basin) – land drained by surface water • Groundwater – Freshwater stored underground • Aquifer – Underground caverns and porous layers of sand, gravel, & rock that stores groundwater

Aquifers

Water Bodies • Rivers – Bodies of lotic water eventually emptying into oceans • Nile is longest • Amazon has greatest volume • Lakes – Bodies of lentic water surrounded by land • Lake Superior is largest surface area • Lake Baikal is biggest, oldest, & deepest – ~1660 m deep • Seas – Smaller, at least partially enclosed areas of ocean or inland seawater • Caspian Sea is largest enclosed sea • Oceans – Can you name all 5 oceans?

Water Supply Issues • 3 basic categories: – Too much water – Too little water – Poor quality/contamination of water • Balanced water budgets have equal amounts of water coming in as going out in all locations. • Situations Create Changes – Unevenly Distributed Populations, seasonal factors, geography, politics, etc.

Water Usage • Water Uses – World Uses • Irrigation ~ 65% • Energy ~ 25% • Domestic Use ~ 10%

Too Much Water! • Flooding – Both natural and human induced • Removal of water-absorbing plants covering the soil • Construction of building on floodplains

Too Little Water • Causes: – Geography/Climate – Drought – Overdrawing of resources • Aquifer depletion: – Subsidence & Sinkholes – Saltwater Intrusion

• Subsidence- gradual caving or sinking of an area of land • Sinkhole- large surface cavity where an underground cave roof has collapsed • Aquifer depletion- excessive removal of ground water lowers the water table

Problems in US • Overall, US has plentiful water – But shortages exist in many areas • Geographic variations • Seasonal variations

Problems in US • Water shortages in West and Southwest – Water diversion projects • Mono Lake (Eastern CA) – Rivers and streams that once fed this lake are diverted to Los Angeles (275 mi away) – Becoming highly saline – Court ordered water diversion reduction • Colorado River Basin – Provides water for 27 -million people – Numerous dams for Hydropower – Colorado River no longer reaches ocean

Aquifer Depletion

Aquifer Depletion • Ogallala Aquifer – Largest aquifer in the world – Water withdrawn 9 x faster than it is replaced

Global Problems • Water Budgets aren’t Balanced! – Climate Change • Affects type and distribution of precipitation – Reduced snowfall impacts water downstream – Sea level rises will cause saltwater intrusion – Drinking Water • Many developing countries have insufficient water to meet domestic needs

Global Problems – Population Growth • Increase in population increases freshwater requirements • Limits drinking water available • Limits water for agriculture – Sharing Water Resources • Countries upstream discharge pollutants • Water diversion has caused increases in salinity • Potentially volatile situations – Jordan and Nile Rivers v. Sharing is caring!

Dams & Reservoirs • Benefits: – Ensures year-round supply of water – Electricity generation – Recreational activities • Disadvantages – Alters the ecosystem – Reduces sediment load downstream

Dams & Reservoirs • Disadvantages – Impedes wildlife migration • Fish ladders help but are only ~50% effective at best

Water Diversion Projects • Water diverted to areas deficient – California Aqueduct Project • Aqueduct- a bridge to convey water over an obstacle, such as a ravine or valley

Other Water Supplies • Desalinization – Removal of salt from sea water – Two methods: – Distillation – Salt water is evaporated and water vapor condensed – Reverse Osmosis – Forcing salt water through a membrane filter – Very Expensive • Cloud Seeding – Saturation of existing clouds to promote rain. • Involves using dry ice or silver iodide • Need existing clouds • Introducing additional chemicals to environment

Irrigation Issues • Irrigation is largest user of water in the world. • Gravity Flow – ~60% efficient • Center Pivot – ~80% efficient

Irrigation Issues • Drip Irrigation – ~90 -95% efficient

Water Conservation • Reduction of Industrial Water Waste – Stricter laws provide incentive to conserve – Water scarcity/rising costs encourages further recycling • Reduction of Municipal Water Waste – Water saving household fixtures – Government incentives – Gray water (aka reuse) • Can be used for toilets, wash cars, water lawns • Reclaimed Water- treated wastewater that is reused in some way. • Black Water- TOILET WATER- GROSS!

Soil Resources • Soil – Controls the distribution of rainfall, regulates biological activity, and filters water, air, and nutrients. • Parent Material- soil that is slowly broken down into smaller pieces by chemical, biological, and physical weathering processes in nature – Soil Forming Factors • Parent Material • Time • Climate • Organisms • Topography

Soil • Not just dirt! • Mixture of eroded rock, minerals, inorganic nutrients, decaying organic matter, water, air, and living organisms. • Soil Composition – 45% mineral matter • weathered rock – 5% organic matter • detritus – 25%water – 25% air

Soil

Soil Layers • Horizons – soil forms in horizontal layers called horizons – most plant roots are in the first two layers – O Horizon • surface litter layer • freshly fallen and partially decomposed organic material – leaves, twigs, fungus, animals, etc. – A Horizon • topsoil layer • aka: humus • richest soil with dark coloring indicating high N content

Soil Layers – E Horizon • strong leaching – filtration – B Horizon • subsoil • inorganic material – sand, silt, clay, gravel – C Horizon • parent material • pieces of rock – Bedrock • unweathered rock

Soil Layers

Soil Structure • Clay – smallest particle size • retains water well, poor drainage • Silt – medium sized particles • advantage of both sand clay • Sand – relatively large particle size • good aeration but poor water retention

Soil Structure • Gravel – largest particle size • no water retention but good water filtration • Loam – mixture of particles

Soil Structure

Soil Quality • Porosity – measure of the volume of pore spaces for air, water, and habitat • Structure – composition of particles determines a soil’s texture, how well it holds together, and if it will support roots • Sorting – how well defined the different particles of soil are • Permeability – speed of water transportation or drainage

Soil Quality • Conductivity – how well it conducts electricity • Nutrient Retention – 6 primary nutrients • N, P, K, Ca, Mg, S • Stability – ability to hold together and resist erosion • p. H – Affects solubility of certain plant nutrients – Optimum soil p. H is 6– 7, because nutrients are most available to plants at this p. H

Erosion • Removes soil and ruins surface water where the soil is deposited. • Causes – primarily by wind and water – also human activities • logging, farming, ranching, construction • Accelerated by poor agricultural practices

Erosion • Great Dust Bowl of 1930 s – severe drought • 1930 -1937 – poor agricultural practices • no natural vegetative roots to hold soil in place

Agricultural Degredation • Soil Salinization – Gradual accumulation of salt in the soil, usually due to improper irrigation techniques

Agricultural Degredation • Desertification – Conversion of lands once productive into deserts.

Increasing Crop Production • Fertilizer Methods/Types – Organic Fertilizers • Animal manure – improves soil structure, adds N, stimulates beneficial bacteria and fungi • Green manure – freshly cut vegetation clippings – Increases organic material and humus • Compost – broken-down organic matter such as leaves, food wastes, wood – Inorganic Fertilizers • produced from various minerals • account for ¼ of all crop yields

Soil Conservation • Erosion Reduction Methods: – Conservation Tillage Farming • plowing the land with minimal disturbances • Residues from previous year’s crops are left in place to prevent soil erosion – Crop Rotation • rotate between different crops over a period of years – legume root nodules add N and reduce erosion – Contour Farming • plowing and planting crops in rows along the land rather than along the slope

Soil Conservation • Erosion Reduction Methods: – Terracing • converting sloping agricultural land into terraced level steps – Strip Cropping • planting alternating strips of crops in order to trap water and soil particles Strip Cropping Terracing

Soil Conservation • Erosion Reduction Methods: – Alley Cropping/Agroforestry/Shelterbelts • several crops are planted between rows of established trees and bushes. • reduces wind erosion of soil

Soil Conservation Laws • Soil Conservation Act of 1935 – authorized formation of Soil Conservation Service, now called Natural Resource Conservation Service (NRCS) – assess soil damage and develop BMPs to improve soil • Food Security Act (Farm Bill) 1985 – farmers with highly erodible soil had to change their farming practices – instituted Conservation Reserve Program • pays farmers to stop farming highly erodible land

Soil Conservation Laws • 1872 Mining Law – Forces government to sell public land leases to private investors at bargain prices – Requires companies to return site to as good of condition, if not better, when completion of mining activity • companies can (and have) abandon site or file for bankruptcy. – leaves taxpayers with the clean-up bill – some sites cost several million dollars to remediate

Mineral Resources • Minerals – Naturally occurring elements or inorganic compounds found in Earth’s crust. • Elements or compounds of elements that occur naturally in the Earth’s crust. • non-renewable resources that can be extracted from known areas. – known as reserves – Rocks • naturally formed aggregates of minerals – Ores • metal yielding rock

Minerals • Unevenly distributed throughout the world • Discovery of new reserves – Scientists (geologists) use a variety of instruments and measurements • Aerial or satellite photography • Seismographs – Combine this with knowledge of how minerals are formed

Mining • Surface Mining – extracts ~90% of minerals in US (60% of coal) – Open-Pit Mining • Fe, Cu, sand & stone – Strip-Mining/Mountain Top Mining • primarily for coal extraction • Subsurface (Traditional) Mining – less environmental damage – less economical and more dangerous to miners

Open Pit Mine

Ore Processing • Smelting – process in which ore is melted at high temps to separate impurities from the molten metal

Mining Effects • Disturbs large area – prone to erosion • Uses large quantities of water – must pump water out of mine to keep it dry • Acid Mine Drainage (AMD) – pollution caused when sulfuric acid and dissolved lead, arsenic or cadmium wash out of mines into nearby waterways

Mining Effects • Mill Tailings – impurities in mined ore – 80% or more of ore – contain toxic materials • Smelting plants – emit large amounts of air pollutants – requires vast amounts of energy

Mining Restoration • Goals • prevent further degradation and erosion of land, eliminate local sources of toxins and make land productive for another purpose • Creative Approaches – Wetlands • trap and filter pollutants before they get into streams • initially expensive, but cost effective compared to using lime to decrease acidity – Phytoremediation • use of specific plants to absorb and accumulate toxic materials in soil

Minerals • Reserves – mineral deposits that have been identified and are currently profitable to extract – Highly developed countries • rely on mineral deposits in developing countries • many have exhausted their own supplies – Developing countries • governments lack financial resources to handle pollution • acid mine drainage, air and water pollution

Minerals

Other Mineral Reserves • Antarctica – no substantial mineral deposits identified to date – Antarctica Treaty of 1961 • limits activity to peaceful uses – Madrid Protocol of 1990 • Moratorium on mineral exploration • Deep Ocean – may provide us with future supplies • extracting minerals from seawater • mining seafloor – manganese nodules

Manganese Nodule Deposits

Mineral Conservation • Reduce – the amount of materials you use • Reuse – lunch boxes, sandwich bags, grocery bags, soda bottles, diapers • Repair – instead of replace

Mineral Conservation • Recycle – Paper is the most recycled item

Four “R’s” • Recycle – USE THE BINS! – Paper is the most recycled item – Primary/Closed Loop Recycling • Waste is recycled into new products of same type – old cans into new cans, old newspaper into newspaper – Secondary/Open Loop Recycling • Convert waste materials into different products – Newspapers into cellulose insulation – Preconsumer/Internal Wastes • wastes from manufacturing process – Postconsumer/External Wastes • wastes generated by the consumer