FRESHWATER

Global Water Distribution● Approximately 71% of the Earth is covered by water.● 97% of that water is salt water.● 69% of the freshwater is frozen in glaciers and ice caps.

Surface WaterSurface Water - is the fresh water on Earth's land surface including lakes, rivers, streams, and wetlands.

WatershedsWatershed - land that is drained by a river. aka River Basin

 * Pollution anywhere in a watershed may end up polluting a river.

DividesDivides are ridges of land (such as a mountain range) that separates one watershed / drainage basin from another.

The “Continental Divide” for North America which determines whether rainfall will make it eventually to the Pacific or to the Atlantic ocean is found along the Rocky Mountains.

Watersheds of North Carolina

River SystemsRiver System - a flowing network of tributaries, streams and rivers.

The Rio Grande

Santa Elena Canyon

Pecos River

Headwaters of the Rio Grande

Amistad ReservoirOrigin: Dam, man-made

The Columbia

River

LakesLakes are depressions that have filled with water.

Natural lakes are made by:• Glaciers• Tectonic or volcanic activity• Meteorites• Oxbow (pinched off meander in a river) aka

billabong

Man-made lakes (aka reservoirs) are created from the damming of a river!

The Great LakesOrigin: Glacial

Lake Tahoe

Origin: Tectonic

The Cascades

St. Helens Before & After

Crater Lake

Origin: Volcanic

Lake Mattamuskeet

North Carolina’s Largest Natural Lake

Water Level•The water level of a lake is maintained typically by a combination of stream outflow and evaporation.

•Saltwater lakes have no stream outflow (the level is maintained strictly by evaporation) which is why they do not eventually become freshwater lakes.

The Great Salt Lake

Racing on the Bonneville Salt Flats

Wetlands

← dolphin

swamp

bogmarsh

Types of Wetlands

EstuariesAn estuary is where fresh water joins salt water.• The water in an estuary is brackish meaning it is

slightly salty.• Estuaries are important spawning/breeding

grounds for many species of fish and birds.

Pamlico Sound

North Carolina’s own Pamlico Sound is the 2nd largest estuary in the country only after the Chesapeake Bay.

GroundwaterGroundwater - Water beneath the Earth's surface in sediment and rock formations. Water table - when water travels beneath the Earth's surface, it eventually reaches a level where rocks and soil are saturated (filled), the zone of saturation.

AquifersAquifer – is an underground formation that contains groundwater.● The water table forms the upper boundary of an aquifer.● Aquifers are an important water source for many cities and for

agriculture.

PorosityPorosity - is the the percentage of the total volume of a rock that has spaces (pores).● Water in an aquifer is stored in the pore space and flows from

one space to another.● The more porous a rock is the more water it can hold.

PermeabilityPermeability - the ability of rock or soil to allow water to flow through it. ● Porous materials such as gravel and sand allow water to flow

easily through● Less porous materials such as clay and slate do not allow water

to flow through

Wells● If you dig anywhere on Earth deep

enough you will eventually find water.● A hole that is dug or drilled to reach

groundwater is called a well.● We dig wells because they are a more

reliable source of water.    

 *Note if the water table   falls below the well, you   will have to drill deeper   to continue getting water.

Septic Tanks - handle the processing of wastewater on-site. They are often found in tandem with wells.

Wastewater Treatment

• For plumbing connected to the city sewage system water flows out of the house through a series of pipes that carry it to a wastewater treatment plant.

• At the wastewater treatment plant, water is filtered and treated to make the water clean enough to return to a river or lake.

Sewer Sludge

• Sewage sludge is the solid material that remains after water treatment.

• Sludge that contains dangerous toxic chemicals must be disposed of as hazardous waste.

• Sewage sludge disposal has prompted creative uses for the waste –If the toxicity of sludge can be reduced to safe

levels, it can be used as a fertilizer. –Sludge can be combined with clay to make

bricks that can be used in buildings.

• Most municipal water supplies are provided by reservoir lakes (man-made by damming).

• For instance our municipal water supply originates at Falls Lake.

• Before the water comes out of your faucet it is first treated with a very similar process to wastewater treatment.

• It is often stored in water towers before it is distributed to homes.

Water Pollution• Pollutants are substances that do harm to the

environment including toxic chemicals, human & animal waste, fertilizers, herbicides and pesticides.

• The two underlying causes of water pollution are industrialization and rapid human population growth.

• In developing parts of the world, often the only water available for drinking is polluted with sewage and agriculture runoff, which can spread waterborne diseases.

Groundwater Pollution• Pollutants usually enter groundwater when polluted

surface water percolates down from the Earth’s surface.

• Pesticides, herbicides, chemical fertilizer, and petroleum products are common groundwater pollutants. Other sources of pollution include septic tanks, unlined landfills, and industrial wastewater lagoons.

Types of Pollution

There are two types of pollution:• Point Source - comes from a specific

site• Nonpoint Source - comes from many

sources rather than from a single specific site

Point Source Pollution

Although point-source pollution can often be identified and traced to a source, enforcing cleanup is sometimes difficult.

Nonpoint Source Pollution

Controlling nonpoint source pollution depends on public awareness of the effects of activities such as spraying lawn chemicals.

Eutrophication

• When extra nutrients enter the water, algae can form large floating mats, called algal blooms.

• As the algae die and decompose, most of the dissolved oxygen is used and fish and other organisms suffocate.

Artificial Eutrophication• Artificial eutrophication - an increase in the

amount of nutrients in a body of water through human activities, such as waste disposal and land drainage.

• The major causes of eutrophication are nitrates in fertilizer and phosphates in some laundry detergents.

Thermal Pollution• Thermal pollution is a temperature increase in a body

of water that is caused by human activity.

• Thermal pollution can occur when power plants and other industries discharge warm water into a lake or river.

• If the flow of warm water into a lake or stream is constant, it may cause the total disruption of an aquatic ecosystem by lowering the amount of dissolved oxygen.

Cleaning up Groundwater• Groundwater pollution is one of the most challenging

environmental problems in the world.• Groundwater recharges (refills) very slowly, so the

process for some aquifers to recycle water and purge contaminants can take hundreds of years.

• Pollution can cling to the materials that make up an aquifer, so even if all of the water in aquifer were pumped out and replaced with clean water, the groundwater could still become polluted.

Laws About Water Pollution• The Clean Water Act of 1972 was to designed to

“restore and maintain the chemical, physical, and biological integrity of the nation’s waters.”

• The Marine, Protection, Research, and Sanctuaries Act of 1972 strengthened the laws against ocean dumping.

• The Oil Pollution Act of 1990 requires all oil tankers traveling in U.S. waters to have double hulls by 2015 as an added protection against oil spills.

Monitoring Water Quality

• For the health of the environment and living organisms (in particular HUMANS) it is of utmost importance that we monitor our water supply.

• The EPA (Environmental Protection Agency) sets the water quality standards for us.

• There are many INDICATORS of water quality, meaning things that tell us about the health of the water.

Indicators • Temperature• Dissolved oxygen (O2) content• pH• Nitrate & phosphate levels• Turbidity• Various bio-indicators

TemperatureLOW TEMPERATUREGOOD (high) dissolved

oxygen levels

HIGH TEMPERATUREBAD (low) dissolved

oxygen levels

Dissolved Oxygen• Aquatic (water) animals require oxygen to

breathe just as terrestrial (land) animals do.

• They get theirs from oxygen that is dissolved in water.

• Low dissolved oxygen is common when water temperatures are abnormally high.

pH• pH = potential hydrogen• Measures a substance's ability to create

hydrogen ions in water or in other words “rip apart water molecules”

AcidsProduce H+ ions in H2OEx: HCl → H+ + Cl-

Properties:•Tastes sour• Corrosive reaction w/metal• Reacts w/CO3

2- to make CO2

• Turns blue litmus paper red

Examples of Acids• HCl – hydrochloric acid• Fertilizers – Nitric & Phosphoric Acid•CH3CO2H – acetic acid (vinegar)• Ascorbic Acid – Vitamin C (citrus)• Lactic Acid•H2SO4 – sulfuric acid

BasesProduce OH- ions in H2OEx: NH3 + H2O → NH4

+ + OH-

•Tastes bitter• feels slippery• Turns red litmus paper blue

Examples of Bases• NaHCO3 – baking soda • household cleaners including:

• NH3- ammonia• Drain Cleaner

StrengthThe strength of an acid or a base is based on how well it produces ions in water.Substances are given a number as a measure of their strength along the pH scale.Strong Acids• HCl – hydrochloric acid• H2SO4 – sufuric acidStrong Bases• NaOH – sodium hydroxide• Drain cleaner

Safety• KNOW the pH of the substance you are working with.• If you cannot know always ASSUME it is STRONG!• ALWAYS wear goggles…even if it’s a dilute solution!• For cleaning up spills…Pour acid on a base & base on an acid…because…

pH as a Water Quality Indicator• Freshwater should have a pH ~ 7• Oceanwater should be ~ 8• Low pH (acidic) indicates the presence of acid rain• High pH (basic/alkaline) indicates the presence of

ammonia which is a product of decay (from eutrophication).

• High pH can also indicate presence of fertilizers in high concentration which could have caused the eutrophication artificially.

Turbidity

• Turbidity refers to how CLEAR the water is.• Turbid is the OPPOSITE of clear.• Turbid water is UNHEALTHY because sunlight cannot

penetrate it well meaning that photosynthesis cannot take place which could cause ecosystem collapse.

• Turbidity is measured by what depth at which a Secchi Disk disappears from view.

BioindicatorsBioindicators are LIVING organisms that can survive only under unique environmental conditions. Their presence or absence from a body of water tell us about the quality of the water. Here are some examples: