Water-Overview of Water-Overview of SurfaceWater (dams, SurfaceWater (dams,

water cycle, etc)water cycle, etc)

WATERWATER’’S IMPORTANCE, S IMPORTANCE, AVAILABILITY, AND RENEWALAVAILABILITY, AND RENEWAL

Water keeps us alive, moderates climate, Water keeps us alive, moderates climate, sculpts the land, removes and dilutes sculpts the land, removes and dilutes wastes and pollutants, and moves wastes and pollutants, and moves continually through the hydrologic cycle.continually through the hydrologic cycle.

It is renewable if kept It is renewable if kept ““cleanclean””..

Fig. 14-3, p. 308

Unconfined Aquifer Recharge Area

Precipitation Evaporation and transpiration Evaporation

Confined Recharge Area

Runoff

Flowing artesian well

Recharge Recharge Unconfined Unconfined AquiferAquifer

Stream Well requiring a pumpInfiltration Water

table LakeInfiltration

Unconfined aquifer

Confined aquiferConfining impermeable rock layer Confining impermeable rock layer

Less permeable Less permeable material such as claymaterial such as clay

Where is the water?Where is the water?

97% of the water on earth is saltwater.97% of the water on earth is saltwater.

Only about 0.02% of the earthOnly about 0.02% of the earth’’s water s water supply is available to us as liquid freshwatersupply is available to us as liquid freshwater

Water UsageWater Usage

47% Agricultural47% Agricultural

44% Industrial44% Industrial

9% Residential9% Residential

Wisconsin—100 gallons per person dailyWisconsin—100 gallons per person daily

Types of Surface WaterTypes of Surface Water1.1. Lentic- non-flowingLentic- non-flowing

a.a. Lake-larger, more diverse, often more Lake-larger, more diverse, often more oxygenoxygen

b.b. Pond-smaller, less diverse, less oxygen. Pond-smaller, less diverse, less oxygen. Light penetrates entire body of waterLight penetrates entire body of water

2.2. Lotic- flowingLotic- flowing

a.a. River- larger, more volumeRiver- larger, more volume

b.b. Stream- smaller, less volumeStream- smaller, less volume

COLD vs WARM Water and OxygenCOLD vs WARM Water and Oxygen

(cold holds more oxygen!)(cold holds more oxygen!)

Cont.Cont.

3.3. Wetlands- terrestrial areas saturated part of Wetlands- terrestrial areas saturated part of the time with water. Can be fresh or saltwater.the time with water. Can be fresh or saltwater.

Wetland ServicesWetland Services

a.a. BiodiversityBiodiversity

b.b. Water Trap (flood control)Water Trap (flood control)

c.c. Carbon Dioxide TrapCarbon Dioxide Trap

d.d. Pollutant TrapPollutant Trap

WATERWATER’’S IMPORTANCE, S IMPORTANCE, AVAILABILITY, AND RENEWALAVAILABILITY, AND RENEWAL

Some precipitation infiltrates the ground and is Some precipitation infiltrates the ground and is stored in soil and rock (groundwater).stored in soil and rock (groundwater).

Water that does not sink into the ground or Water that does not sink into the ground or evaporate into the air runs off (surface runoff) into evaporate into the air runs off (surface runoff) into bodies of water.bodies of water.

The land from which the surface water drains into The land from which the surface water drains into a body of water is called its a body of water is called its watershedwatershed or or drainage basindrainage basin. (Mississippi—30 states). (Mississippi—30 states)

WATER POLLUTION: SOURCES, WATER POLLUTION: SOURCES, TYPES, AND EFFECTSTYPES, AND EFFECTS

Water pollutionWater pollution is any chemical, biological, is any chemical, biological, or physical change in water quality that has or physical change in water quality that has a harmful effect on living organisms or a harmful effect on living organisms or makes water unsuitable for desired uses.makes water unsuitable for desired uses.– Point sourcePoint source: specific location (drain pipes, : specific location (drain pipes,

ditches, sewer lines).ditches, sewer lines).– Nonpoint sourceNonpoint source: cannot be traced to a single : cannot be traced to a single

site of discharge (atmospheric deposition, site of discharge (atmospheric deposition, agricultural / industrial / residential runoff) agricultural / industrial / residential runoff)

Dangers to Surface WaterDangers to Surface Water

Eutrophication-decrease in oxygen in a body Eutrophication-decrease in oxygen in a body of water. of water. – Can be caused by algal blooms due to Can be caused by algal blooms due to

increased levels of nitrates and phosphates in increased levels of nitrates and phosphates in water.water.

– Nitrates and phosphates come from sewage, Nitrates and phosphates come from sewage, farm runoff (animal wastes), and fertilizers that farm runoff (animal wastes), and fertilizers that enter surface water.enter surface water.

POLLUTION OF FRESHWATER POLLUTION OF FRESHWATER STREAMSSTREAMS

Most developed countries have sharply Most developed countries have sharply reduced point-source pollution but toxic reduced point-source pollution but toxic chemicals and pollution from nonpoint chemicals and pollution from nonpoint sources are still a problem.sources are still a problem.

Stream pollution from discharges of Stream pollution from discharges of untreated sewage and industrial wastes is untreated sewage and industrial wastes is a major problem in developing countries.a major problem in developing countries.

Global Outlook: Stream Pollution Global Outlook: Stream Pollution in Developing Countriesin Developing Countries

Water in many of Water in many of central China's central China's rivers are greenish rivers are greenish black from black from uncontrolled uncontrolled pollution by pollution by thousands of thousands of factories.factories.

Figure 21-5Figure 21-5

PREVENTING AND REDUCING PREVENTING AND REDUCING SURFACE WATER POLLUTIONSURFACE WATER POLLUTION

Most developed countries use laws to set Most developed countries use laws to set water pollution standards, but such laws water pollution standards, but such laws rarely exist in developing countries.rarely exist in developing countries.– The U.S. Clean Water Act sets standards fro The U.S. Clean Water Act sets standards fro

allowed levels of key water pollutants and allowed levels of key water pollutants and requires polluters to get permits.requires polluters to get permits.

– EPA is experimenting with a EPA is experimenting with a discharge discharge trading policytrading policy similar to that for air pollution similar to that for air pollution control.control.

Reducing Water Pollution through Reducing Water Pollution through Sewage Treatmentn (Septic)Sewage Treatmentn (Septic)

Septic tanks and various levels of sewage Septic tanks and various levels of sewage treatment can reduce point-source water treatment can reduce point-source water pollution.pollution.

Figure 21-15Figure 21-15

Reducing Water Pollution through Reducing Water Pollution through Sewage TreatmentSewage Treatment

Raw sewage reaching a municipal sewage Raw sewage reaching a municipal sewage treatment plant typically undergoes:treatment plant typically undergoes:– Primary sewage treatmentPrimary sewage treatment: a : a physicalphysical process process

that uses screens and a grit tank to remove that uses screens and a grit tank to remove large floating objects and allows settling.large floating objects and allows settling.

– Secondary sewage treatmentSecondary sewage treatment: a : a biologicalbiological process in which aerobic bacteria remove as process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, much as 90% of dissolved and biodegradable, oxygen demanding organic wastes.oxygen demanding organic wastes.

Reducing Water Pollution through Reducing Water Pollution through Sewage TreatmentSewage Treatment

Primary and Secondary sewage treatment.Primary and Secondary sewage treatment.

Figure 21-16Figure 21-16

Reducing Water Pollution through Reducing Water Pollution through Sewage TreatmentSewage Treatment

Advanced or tertiary sewage treatment:Advanced or tertiary sewage treatment:– Uses series of chemical and physical Uses series of chemical and physical

processes to remove specific pollutants left processes to remove specific pollutants left (especially nitrates and phosphates).(especially nitrates and phosphates).

Water is chlorinated to remove coloration Water is chlorinated to remove coloration and to kill disease-carrying bacteria and and to kill disease-carrying bacteria and some viruses (disinfect). some viruses (disinfect).