CommunityWatersStudyGuide

"Community Waters"

Study Guide

Every community -- city, village, township -- is located in a watershed. Your community has a low point -- a stream, river, pond, lake, or other body of water into which all of the water in your community eventually flows. The body of water and the land area it drains is called a watershed. A watershed is something like a bowl, and the rim of the bowl is the higher ground surrounding the watershed. Water and melting snow flow down from the higher ground through city streets, roads, fields and lawns carrying sediment and pollutants with it to the bottom of the bowl or the river, lake, or ocean.

The largest watershed in Minnesota and in the United States is the Mississippi River Watershed, which flows into the Gulf of Mexico. Water from thirty-one states (including most of Minnesota) and two Canadian provinces drains into it. The Rocky Mountains in the west and the Appalachian Mountains in the east are the rim of the bowl, the highest ground in the Mississippi watershed. Other major watersheds in Minnesota include the Red River and Rainy River in northern Minnesota, which flow into the Arctic Ocean, and water in northeastern Minnesota, which flows into Lake Superior and the Atlantic Ocean.

There are thousands of smaller watershed areas throughout Minnesota, the United States, and the world. Small watersheds as small as a corner of a yard that drains into a creek, flow together to make up a huge watershed like the Mississippi watershed where the major river flows to the ocean. These smaller watersheds are watersheds by themselves, but they are also part of a larger watershed similar to the branches of a tree joining together to form the trunk.

The spring floods of 1997 and 2001 on the Red River and the Minnesota River and the summer floods of 2000 on the Red River, in Eagan, and on the Cedar River in southeastern Minnesota illustrate how all of the smaller watersheds, the branches of the tree, flow together to become a part of the larger watershed, the trunk of the tree. Surface runoff from the rain carried with it what each person in each community had put into the water and showed how each person in each community had used the land in all of those watersheds.

A broken sewer line in Moorhead may affect the water all the way to the Arctic Ocean. Batteries and gasoline stored in a garage in Eagan may affect the water all the way to the Gulf of Mexico. What happens in one area of a community's watershed may affect distant parts of the larger watershed.

What you put into the water, how you use the land, and how you use the water available to you is likely to affect the water and its users in your watershed and many other watersheds. The water quantity and quality reflects all of the human activities and natural conditions in your community.

Your Community Water

Water, a most familiar, unique, and vulnerable natural resource, appears in three distinct forms -- solid, liquid, and gas. The form it takes depends on its temperature. At low temperatures, the molecules move slowly because they have less energy. This produces ice, the solid form of water. At medium temperatures, when the molecules move freely because of extra heat energy, water is liquid. The water molecules are close together, yet they slip around freely. This gives water its liquid, flowing motion. At high temperatures, the molecules move about violently, colliding with one another, and form an invisible gas -- water vapor.

Water, the liquid of life, is one of the essential ingredients which makes human, plant, and animal life possible. All living things need water. Water in the body lubricates joints and tissues, forms a lens in an eye, and regulates body temperature. The human body needs five and a half pints of water each day and is 65% water.

Two-thirds of the earth's surface is covered with water. Minnesota alone has more than 12,000 lakes, 92,000 miles of rivers and streams, 10.6 million acres of wetlands, and extensive underground water.

Although water covers two-thirds of the earth's surface, over 99% of that water is unusable. It is either too salty (97% is in the oceans) or frozen (2% is locked in ice caps and glaciers.) Less than 1% of the earth's water is available to be used by humans, plants, and animals.

The total amount of water in the world remains the same. The water that you use today may have been used by a dinosaur millions of years ago or by a farmer to irrigate a field last year. Water moves from place to place, gets dirty and then gets cleaned. Your community waters get recycled again and again.

Water's hydrologic cycle moves your community water from place to place and cleans or purifies it naturally. The hydrologic cycle is one of the largest physical processes occurring on earth. This circulating system for the earth's water is in constant motion. Water moves from the earth to the atmosphere and back again through several pathways (see diagram at left). Those pathways include:

Condensation -- from cloud to air,
Precipitation -- from cloud to earth's surface,
Evaporation -- from surface to air,
Infiltration -- from surface to soil,
Transpiration -- from soil through plants to air,
Percolation -- from soil to groundwater, and
Runoff -- from surface to river or lake.

The hydrologic cycle delivers huge amounts of water to the earth's watersheds but not always the right amount to the right places -- as shown by the floods in some communities and at the same time other communities are experiencing drought.

The stage of the hydrologic cycle that does the most to purify the water is evaporation. As the water evaporates, the mineral salts, bacteria, and viruses are left behind. Only the water molecules are pulled into the air.

In many communities, you have two sources from which you can get your usable water. Surface water is the water you see -- lakes, rivers, ponds, and streams. Many communities rely on surface water for public use.

Groundwater is water stored beneath the earth's surface. Groundwater slips in pores, cracks, crevices, and fractures in rock and also squeezes between loose sand and gravel. There is thirty times more water underground than in all the lakes and rivers put together.

Water is labeled groundwater only after it infiltrates or percolates through the ground. As rain water soaks into the ground, it goes first through the unsaturated zone, that area near the surface where spaces between soil particles contain both water and air, and the water is made available to plants. If it is not used or not evaporated, the water will continue downward to the saturated zone where water occupies all spaces in the soil. The top of this saturated zone is called the water table.

A groundwater source in a watershed that is large enough to supply a well or spring is called an aquifer. To be considered a good aquifer, it must have the ability to store water (porosity), and have the ability to transmit water (permeability). The greater the porosity and permeability, the better the aquifer is as a usable source of water.

Confined aquifers (artesians) are those sandwiched between impermeable layers of rock or clay in a watershed. Unconfined aquifers (water table) are those that are fed by precipitation that has managed to avoid use by plants, avoid a path into a stream, or has not evaporated but has found its way down through the ground in a watershed to the water table.

Recharge areas are areas where water enters the groundwater system. Recharge ponds, built to contain rainfall, allow water to naturally seep back into the ground, thus recharging unconfined aquifers.

At discharge areas, groundwater reappears at the surface of the ground. It then flows to lower surface water areas like lakes, streams, wetlands, or it moves through pumping wells or irrigation systems.

This endless process of exchanging water through pathways makes almost no changes in the total amount of water in the world, but the change in the 1% of usable water is pronounced. Both natural conditions and human activities affect the water quantity and quality of the surface and groundwater in your community.

Not Enough Community Waters

The water table in a watershed fluctuates according to the amount of precipitation or the amount of water that is taken from an aquifer. Although a tremendous amount of usable water comes from them, human activities often disrupt aquifers in a watershed.

In the United States, 80-90% of the total available water supply comes from the ground. Of the various uses of water, the following percentages come from groundwater:

* Drinking water

50%

* Irrigation water

40%

* Rural water use

80% (household , livestock)

* Industrial Use

25%

Increased pumping of one area of an aquifer can affect water availability in other areas. Caution must be taken that water is not pumped out of an aquifer faster than it can be replaced, for the weight of the soil above the aquifer could collapse, causing expensive property damage. It could also reduce the size of the aquifer, and as a result, the amount of water it can hold the future. Although "sinkholes" are considered a natural phenomenon, increased groundwater withdrawal seems to be connected to an increase in the number of sinkholes.

The diversion of streams and the draining of wetlands within a watershed also mean a change of location and amount of water found there. The paving of streets and parking lots prevents rainfall from entering the soil, and thus from recharging the aquifer.

Changes in the type or amount of vegetation on the surface of the land in your community can change the amount of water entering an aquifer. The roots of new vegetation may absorb the water which was previously used for recharge. On the other hand, loss of vegetation may result in increased surface runoff, again preventing recharge for the aquifer.

Drawdown is the decline in the water level due to excessive groundwater withdrawals resulting in depletion of an aquifer. "Water mining," withdrawing water from aquifers at a rate greater than the rate of recharge, can lead to overdraft, a continued decline due to long-term withdrawal.

The current withdrawal of both ground and surface water -- the 1% of usable water -- is great. Industry uses huge quantities of water -- about 140 billion gallons per day. Production of food also places a heavy demand on the water. To produce the grain for one loaf of bread, 150-300 gallons of water are needed. 2,500-4,000 gallons of water are needed to produce one pound of beef.

Transportation uses water in the shipping of ores, fuel oil, coal, and grain. Water is also used for recreation: swimming, boating, sailing, water skiing. Wildlife places a demand on water for its internal needs as well as for its home.

And humans... well, we each use tremendous quantities of water each day. In the United States, it has been estimated that the average person directly uses 87 gallons of water a day. Some other estimates go as high as 300 gallons a day in areas where lawn watering is extensive.

Community Waters Aren't Always Clean!

The quantity of surface and ground water in your community reflects what you and others who live in your community do to the land, how you and others use the water, and the amount of precipitation in your watershed. These factors also affect the quality of the water in your community.

Any water supply, no matter how great in quantity, is absolutely useless if it has been contaminated with harmful chemicals and sediment. Therefore, without the required quality, any quantity of water is the same as no water at all!

Contamination of the water in your community can occur when undesirable substances are in the air, the water, or the soil. As water moves throughout the hydrologic cycle, its quality is susceptible to contamination by natural actions and the actions of humans.

Gases in the air (emissions from cars and industrial plants) mix with the moisture to form acidic compounds that fall to the earth as rain, snow, or dust. The ability of this acid rain or acid precipitation to affect the environment is long-reaching for it can travel far, unhindered by political boundaries.

Water picks up natural and human substances as it moves over and through the watershed. The force of rain falling on the earth and water running across the earth's surface is very great. Surface water picks up and carries rocks, soil, plants, and many other objects. The results can be either beneficial or destructive.

In addition, water can be polluted by excessive rates of erosion when it contains chemicals (fertilizers, pesticides) which are attached to the eroding soil. For example, as the water moves over the watershed's surface, it becomes contaminated from:

fertilizers and pesticides from lawns, golf courses, and farms,
animal wastes,
silt from building and highway construction sites or logging operations,
oil, grease, and gasoline from improper disposal, spills, or leaks from motor vehicles,
road salt,
and runoff from streets and parking lots carrying pollutants such as antifreeze, transmission fluid, and other debris.

As the water percolates through the ground, it also becomes contaminated before reaching the water table from:

leaking septic tanks and sewage treatment plants,
leaking underground fuel storage tanks,
and leaking landfills, and illegal dumps.

As this contaminated water enters the saturated zone, it contaminates the groundwater which can remain contaminated for hundred or even thousands of years. Because aquifers which store your groundwater are not visible, you cannot see or smell changes in them as easily as you can changes in surface water. There is no "early warning system" for groundwater contamination. Water tends to move very slowly in aquifers, therefore the contamination is also slow and spreads unpredictably.

Once contamination takes place, it is virtually impossible to clean up, and the solutions are costly. An article in the July/August, 1990 issue of Minnesota Environment states that "about the only remedy is to determine how far the contamination has spread, and then pump the water out of the ground and purify it. This remedy is currently in place or proposed for dozens of sites in Minnesota.... In the largest groundwater cleanup in Minnesota, the Twin Cities Army Ammunition Plant project, 17 wells are pumping three to five million gallons of contaminated groundwater per day for treatment, and will continue to do so for the next 20-30 years. The cost is estimated to run above $4 million." This is just one example of why it is necessary to prevent contamination.

A single identifiable source of direct contamination in your community, such as a factory pipe spewing waste into a river, is a point source of contamination. A nonpoint source of pollution is not as easy to see. It may be caused by wind or water erosion, moving pollutants into the surface water which may eventually also seep into your community's groundwater supply.

Nonpoint sources of pollution can result from:

using too much fertilizer on a lawn, golf course, or a field,
allowing soil to blow away from a chemically treated agricultural field,
poorly maintained septic tanks,
erosion at construction sites,
uncapped wells,
poorly stored road sand and salt, and
shoreline destruction, to name a few.

One example of the devastating results of point and nonpoint source pollution is hypoxia, water conditions unsuitable to sustain marine animals due to inadequate dissolved-oxygen concentrations, affecting an area in the Gulf of Mexico sometimes called the "Dead Zone," covering from 4,800 to over 7,000 square miles. The Mississippi River watershed which begins in Minnesota carries nitrogen and phosphorus from agricultural fields, lawns, sewage, industrial discharge, and animal waste throughout the entire watershed to the Gulf of Mexico creating the hypoxia.

The above types of contamination are serious and widespread, yet it is contamination from our "accepted" waste disposal practices that is responsible for many incidents of water contamination.

Products commonly used in the home such as paint, varnish, bleach, scouring powder, medicines, motor oil, and oven cleaner are extremely hazardous, yet little thought is given to the potential for water contamination when these products are discarded. For example, one gallon of spilled motor oil can contaminate one million gallons of water.

Protect Your Community Waters

Many experts believe that protecting your community waters begins with watershed management. Because our usable water supply is a result of precipitation, the quality of each drop can be affected where it lands -- the kind of soil and its cover (vegetation, unprotected soil, parking lot, or pavement). It is important to encourage soil conservation and runoff prevention because soils and nutrients belong on our lands, not in our waters.

Contour tillage, terraces, and grassed waterways slow the water down and hold runoff on the land where it can soak into the soil to provide moisture for the growing crop as well as recharge underground water supplies.

Conservation tillage, no-till, minimum tillage, and ridge till are effective means for both conserving soil moisture and preventing soil erosion. The crop residue reduces runoff, allowing more water to soak into the soil, storing it for use during dry periods. The residue keeps the ground cooler, reducing transpiration and evaporation and allows the crop to use the water more effectively.

Wetlands play a major role in protecting the water in your community because they act like a filtering system to remove excessive nutrients and chemicals from the surface and groundwater. Wetlands also provide a natural retention basin for floodwater by collecting and retaining large volumes of runoff,. It is very important to preserve wetlands in your watershed for these natural functions.

Avoiding overuse of fertilizers, pesticides, herbicides and other chemicals is essential. Application to lawn, garden, or crops should carefully follow application rates recommended on the basis of soil tests. Also consider planting native plants which need fewer chemicals and water in your lawn or garden.

Many experts also believe that wise use of all resources is the best way to ensure an adequate, usable water supply. Of course, considerable amounts of water can be saved by just watching your own water use. Don't waste it.

What Can You Do?

You Can...

Conserve and protect your community waters

Run full laundry and dish loads.
Fix leaky faucets. (Estimates show that from 10% to 20% of the water in major eastern cities is lost through leaky pipes!)
Turn off the faucet while brushing teeth or soaping hands.
Conserve bath and shower water.
Store water in the refrigerator rather than letting the faucet run when you want a glass of cold water.
Water your lawn when the sun is low to cut down on evaporation.
Use natural fertilizers.
Use biodegradable soaps and shampoos.
Don't pour grease, oil, or other hazardous wastes down a sink drain or down the storm sewer or street gutter.
Make sure your septic system is working properly.

Reduce solid waste

Promote alternatives to landfills.
Recycle cans, bottles, papers, motor oil.
Compost.
Buy products made of recycled materials.
Avoid products with wasteful packaging.

Conserve energy

Avoid unnecessary driving.
Keep your car tuned.
Conserve electricity. (Even the best power plants are potential polluters.)

You can also work with others in your community to become "watershed protectors." Learn about the federal and state legislation and the agencies that protect your watershed and community waters. Your local soil and water conservation district (SWCD) works with individuals and other units of government to protect the soil and water in Minnesota's watersheds. The Conservation Reserve Program (CRP) enrolling buffer strips and the CREP combination of Reinvest in Minnesota (RIM) and CRP to enroll 100,000 sensitive acres in Minnesota are two examples of programs to protect water quality.

How many examples of these programs can you find in your community? Are there other examples of your community working together to protect and conserve your community waters?

One point that all water experts agree on is that the economic and environmental costs of obtaining adequate clean water are going to increase and the wise management of our watersheds and the proper use of our community waters will be a major environmental challenge for the future.

Pollution resulting from water's ability to pick up or dissolve substances has always been a natural process on earth. It is human actions that are endangering our watersheds and our water supply as well as putting ourselves at great risk.

You, other people, domestic animals, and wildlife in your community all depend on the water in your watershed and together influence what happens to the community waters and to the community waters in watersheds downstream.

Are you involved in efforts to protect and conserve your community waters?

Community Waters was developed in 2000 by the Minnesota Association of Soil and Water Conservation Districts' Education Committee to provide teachers with a tool for teaching about locally led efforts to conserve and protect Minnesota's soil and water resources. For more information about Community Waters, contact your local Soil and Water Conservation District.