As stormwater flows over driveways, lawns, and sidewalks, it picks up debris, chemicals, dirt, and other pollutants. Stormwater can flow into a storm sewer system or directly to a lake, stream, river, wetland, or coastal water. Anything that nters a storm sewer system is discharged untreated into the waterbodies we use for swimming, fishing, and providing drinking water. Polluted runoff is the nation’s greatest threat to clean water. By practicing healthy household habits, homeowners can keep common pollutants like pesticides, pet waste, grass clippings, and automotive fluids off the ground and out of stormwater. Adopt these healthy household habits and help protect lakes, streams, rivers, wetlands, and coastal waters. Remember to share the habits with your neighbors!
Healthy Household Habits for Clean Water
Vehicle and Garage
• Use a commercial car wash or wash your car on a lawn or other unpaved surface to minimize the amount of dirty, soapy water flowing into the storm drain and eventually into your local waterbody.
• Check your car, boat, motorcycle, and other machinery and equipment for leaks and spills. Make repairs as soon as possible. Clean up spilled fluids with an absorbent material like kitty litter or sand, and don’t rinse the spills into a nearby storm drain. Remember to properly dispose of the absorbent material.
• Recycle used oil and other automotive fluids at participating service stations. Don’t dump these chemicals down the storm drain or dispose of them in
your trash.
Lawn and Garden
• Use pesticides and fertilizers sparingly. When use is necessary, use these chemicals in the recommended amounts. Avoid application if the forecast calls for rain; otherwise, chemicals will be washed into your local stream.
• Select native plants and grasses that are drought- and pest resistant. Native plants require less water, fertilizer, and pesticides.
• Sweep up yard debris, rather than hosing down areas. Compost or recycle yard
waste when possible.
• Don’t over water your lawn. Water during the cool times of the day, and don’t let water run off into the storm drain.
• Cover piles of dirt and mulch being used in landscaping projects to prevent these pollutants from blowing or washing off your yard and into local water bodies. Vegetate bare spots in your yard to prevent soil erosion.
Home Repair and Improvement
• Before beginning an outdoor project, locate the nearest storm drains and protect them from debris and other materials.
• Sweep up and properly dispose of construction debris such as concrete and mortar.
• Use hazardous substances like paints, solvents, and cleaners in the smallest amounts possible, and follow the directions on the label. Clean up spills immediately, and dispose of the waste safely. Store substances properly to avoid leaks and spills.
• Purchase and use nontoxic, biodegradable, recycled, and recyclable products whenever possible.
• Clean paint brushes in a sink, not outdoors. Filter and reuse paint thinner when using oil-based paints. Properly dispose of excess paints through a household
hazardous waste collection program, or donate unused paint to local organizations.
• Reduce the amount of paved area and increase the amount of vegetated area in your yard. Use native plants in your landscaping to reduce the need for watering during dry periods. Consider directing downspouts away from paved surfaces onto lawns and other measures to increase infiltration and reduce polluted runoff.
Friday, May 29, 2009
Wednesday, May 27, 2009
Expensive Heat Pump Water Heaters
1 Heat pump 2 Temperature and pressure relief valve 3 Hot water outlet (to taps) 4 Back-up electric resistance heating element 5 Cold water inlet 6 Compressor 7 Refrigerant lines 8 Evaporator 9 Hot water storage tank 10 Heat exchanger 11 Drain pan
| ENERGY SOURCE | ELECTRICITY |
| MINIMUM EFFICIENCY RECOMMENDED | 2.0 EF |
| MAXIMUM EFFICIENCY AVAILABLE | 2.5 EF |
| EXPECTED LIFE | 11 years |
| ARROXIMATE COST TO INSTALL | $1,000-$1,500 |
Heat pump water heaters move heat from the surrounding air into the water. The heat pump is backed up by electric heating elements in the water tank for when demand outruns supply. Heat pump water heaters may be purchased as integral units with their own storage tanks (called one-piece systems), or they may be added on to electric-resistance water heaters. Heat pump water heaters are expensive, but they are a good alternative if electricity is your only available source of energy. They can save 25% to 45% of the cost of heating water with an electric-resistance heater.
Special Features
In a heat pump, energy is used not to generate heat but to move it, so a heat pump can have an Energy Factor above one. In fact, most heat pumps have EFs between two and three.
When heat pump water heaters move heat into the water, they cool and dehumidify the air surrounding the unit. This produces the equivalent of about 1/2 ton of air conditioning--which is helpful if your home usually needs cooling. But when winter comes, that cool air will put more demand on your heating system.
Precautions
Heat pump systems should be designed and installed by experts. One-piece systems require less design work and are simpler to install. Choose your contractor carefully.
Heat pump water heaters should be installed inside the house because they can freeze up if the temperature drops below 45°F. And they should be in an open, unconfined space, since they need lots of surrounding air from which to extract heat.
Heat pumps require more maintenance visits than most other systems. Depending on your water quality, the heat exchanger coils may need to be cleaned as often as every three months. This is not something most homeowners can do on their own.
Sizing
Heat pumps are slow. Most electric-resistance heaters can heat 20 gallons per hour. Heat pumps usually manage only 10 to 15. If demand exceeds supply, the inefficient backup heaters go on. While a larger storage tank can help you to avoid running out of hot water, it will lead to increased standby loss.
Like other storage units, heat pump water heaters are sized by first-hour rating. However, your contractor will also need to size the backup electric coil. Make sure the heat pump is sized to minimize use of the backup system.
Tuesday, May 26, 2009
Water Evapotranspiration and Transpiration
What is evapotranspiration?
If you search for the definition of evapotranspiration, you will find that it varies. In general, evapotranspiration is the sum of evaporation and transpiration. Some definitions include evaporation from surface-water bodies, even the oceans. But, since we have a Web page just about evaporation, our definition of evapotranspiration will not include evaporation from surface water. On this site, evapotranspiration is defined as the water lost to the atmosphere from the ground surface, evaporation from the capillary fringe of the groundwater table, and the transpiration of groundwater by plants whose roots tap the capillary fringe of the groundwater table. The banner at the top of this page offers an even more simple definition.
The transpiration aspect of evapotranspiration is essentially evaporation of water from plant leaves. Studies have revealed that transpiration accounts for about 10 percent of the the moisture in the atmosphere, with oceans, seas, and other bodies of water (lakes, rivers, streams) providing nearly 90 percent, and a tiny amount coming from sublimation (ice changing into water vapor without first becoming liquid).
Transpiration: The release of water from plant leaves
Just as you release water vapor when you breath, plants do, too – although the term "transpire" is more appropriate than "breath." This picture shows water vapor transpired from plant leaves after a plastic bag has been tied around the stem for about an hour. If the bag had been wrapped around the soil below it, too, then even more water vapor would have been released, as water also evaporates from the soil.
Plants put down roots into the soil to draw water and nutrients up into the stems and leaves. Some of this water is returned to the air by transpiration. Transpiration rates vary widely depending on weather conditions, such as temperature, humidity, sunlight availability and intensity, precipitation, soil type and saturation, wind, and land slope. During dry periods, transpiration can contribute to the loss of moisture in the upper soil zone, which can have an effect on vegetation and food-crop fields.
How much water do plants transpire?
Plant transpiration is pretty much an invisible proces – since the water is evaporating from the leaf surfaces, you don't just go out and see the leaves "breathing". Just because you can't see the water doesn't mean it is not being put into the air, though. One way to visualize transpiration is to put a plastic bag around some plant leaves. As this picture shows, transpired water will condense on the inside of the bag. During a growing season, a leaf will transpire many times more water than its own weight. An acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 liters) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 liters) per year.
Atmospheric factors affecting transpiration
The amount of water that plants transpire varies greatly geographically and over time. There are a number of factors that determine transpiration rates:
Transpiration and ground water
Diagram showing how the water table can dip where plant roots access it during the growing season. In many places, the top layer of the soil where plant roots are located is above the water table and thus is often wet to some extent, but is not totally saturated, as is soil below the water table. The soil above the water table gets wet when it rains as water infiltrates into it from the surface, But, it will dry out without additional precipitation. Since the water table is usually below the depth of the plant roots, the plants are dependent on water supplied by precipitation. As this diagram shows, in places where the water table is near the land surface, such as next to lakes and oceans, plant roots can penetrate into the saturated zone below the water table, allowing the plants to transpire water directly from the ground-water system. Here, transpiration of ground water commonly results in a drawdown of the water table much like the effect of a pumped well (cone of depression—the dotted line surrounding the plant roots in the diagram).
If you search for the definition of evapotranspiration, you will find that it varies. In general, evapotranspiration is the sum of evaporation and transpiration. Some definitions include evaporation from surface-water bodies, even the oceans. But, since we have a Web page just about evaporation, our definition of evapotranspiration will not include evaporation from surface water. On this site, evapotranspiration is defined as the water lost to the atmosphere from the ground surface, evaporation from the capillary fringe of the groundwater table, and the transpiration of groundwater by plants whose roots tap the capillary fringe of the groundwater table. The banner at the top of this page offers an even more simple definition.The transpiration aspect of evapotranspiration is essentially evaporation of water from plant leaves. Studies have revealed that transpiration accounts for about 10 percent of the the moisture in the atmosphere, with oceans, seas, and other bodies of water (lakes, rivers, streams) providing nearly 90 percent, and a tiny amount coming from sublimation (ice changing into water vapor without first becoming liquid).
Transpiration: The release of water from plant leaves
Just as you release water vapor when you breath, plants do, too – although the term "transpire" is more appropriate than "breath." This picture shows water vapor transpired from plant leaves after a plastic bag has been tied around the stem for about an hour. If the bag had been wrapped around the soil below it, too, then even more water vapor would have been released, as water also evaporates from the soil.Plants put down roots into the soil to draw water and nutrients up into the stems and leaves. Some of this water is returned to the air by transpiration. Transpiration rates vary widely depending on weather conditions, such as temperature, humidity, sunlight availability and intensity, precipitation, soil type and saturation, wind, and land slope. During dry periods, transpiration can contribute to the loss of moisture in the upper soil zone, which can have an effect on vegetation and food-crop fields.
How much water do plants transpire?
Plant transpiration is pretty much an invisible proces – since the water is evaporating from the leaf surfaces, you don't just go out and see the leaves "breathing". Just because you can't see the water doesn't mean it is not being put into the air, though. One way to visualize transpiration is to put a plastic bag around some plant leaves. As this picture shows, transpired water will condense on the inside of the bag. During a growing season, a leaf will transpire many times more water than its own weight. An acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 liters) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 liters) per year.
Atmospheric factors affecting transpiration
The amount of water that plants transpire varies greatly geographically and over time. There are a number of factors that determine transpiration rates:
- Temperature:Transpiration rates go up as the temperature goes up, especially during the growing season, when the air is warmer due to stronger sunlight and warmer air masses. Higher temperatures cause the plant cells which control the openings (stoma) where water is released to the atmosphere to open, whereas colder temperatures cause the openings to close.
- Relative humidity: As the relative humidity of the air surrounding the plant rises the transpiration rate falls. It is easier for water to evaporate into dryer air than into more saturated air.
- Wind and air movement: Increased movement of the air around a plant will result in a higher transpiration rate. This is somewhat related to the relative humidity of the air, in that as water transpires from a leaf, the water saturates the air surrounding the leaf. If there is no wind, the air around the leaf may not move very much, raising the humidity of the air around the leaf. Wind will move the air around, with the result that the more saturated air close to the leaf is replaced by drier air.
- Soil-moisture availability: When moisture is lacking, plants can begin to senesce (premature ageing, which can result in leaf loss) and transpire less water.
- Type of plant: Plants transpire water at different rates. Some plants which grow in arid regions, such as cacti and succulents, conserve precious water by transpiring less water than other plants.
Transpiration and ground water
Diagram showing how the water table can dip where plant roots access it during the growing season. In many places, the top layer of the soil where plant roots are located is above the water table and thus is often wet to some extent, but is not totally saturated, as is soil below the water table. The soil above the water table gets wet when it rains as water infiltrates into it from the surface, But, it will dry out without additional precipitation. Since the water table is usually below the depth of the plant roots, the plants are dependent on water supplied by precipitation. As this diagram shows, in places where the water table is near the land surface, such as next to lakes and oceans, plant roots can penetrate into the saturated zone below the water table, allowing the plants to transpire water directly from the ground-water system. Here, transpiration of ground water commonly results in a drawdown of the water table much like the effect of a pumped well (cone of depression—the dotted line surrounding the plant roots in the diagram).
Monday, May 25, 2009
History of Water Shortage
Our subtropic region has two seasons: the rainy and the dry season, which can bring short-term excesses and shortages: in a natural cycle of flood and drought. We also have one of the nation's fastest growing populations, which increases demand and can decrease supplies of water storing lands. Seasonal shortfalls of rain can stress both ground and surface waters, which can require the declaration of a water shortage, and mandatory limits on irrigation.
Our dry season usually starts in November, and continues through May. Temperatures fall and humidity decreases, but not radically. From spring through winter, millions of seasonal visitors visit the region, further increasing the demand for water.
Changing Our Landscape
Our region was, less than 100 years ago, a wetlands studded peninsula which was wet for most of the year. The early settlers clustered near the thin strip of higher ground created by coastal ridges, which, like the sides of a bowl kept water stored in inaccessible inland swamps.
In today's far more densely developed region, the rainy season and the dry season can quickly bring flooding and drought -- because there are few places quite as flat, or as blessed with rainfall (an average 53 inches a year) and population growth (about 7.5 million residents and millions of seasonal visitors). More than 90% of us get our drinking water from groundwater sources, which are primarily replenished by rainfall. Treating sea water or surface water for consumption is far more expensive, and therefore, rarer than most believe.
Managing Emergencies
When water levels are too high, or too low, SFWMD Emergency Management Operations monitors and optimizes regional water management.
Our dry season usually starts in November, and continues through May. Temperatures fall and humidity decreases, but not radically. From spring through winter, millions of seasonal visitors visit the region, further increasing the demand for water.
Changing Our Landscape
Our region was, less than 100 years ago, a wetlands studded peninsula which was wet for most of the year. The early settlers clustered near the thin strip of higher ground created by coastal ridges, which, like the sides of a bowl kept water stored in inaccessible inland swamps.
In today's far more densely developed region, the rainy season and the dry season can quickly bring flooding and drought -- because there are few places quite as flat, or as blessed with rainfall (an average 53 inches a year) and population growth (about 7.5 million residents and millions of seasonal visitors). More than 90% of us get our drinking water from groundwater sources, which are primarily replenished by rainfall. Treating sea water or surface water for consumption is far more expensive, and therefore, rarer than most believe.
Managing Emergencies
When water levels are too high, or too low, SFWMD Emergency Management Operations monitors and optimizes regional water management.
Friday, May 22, 2009
Water Storage Information in the Atmosphere
The atmosphere is full of water
The water cycle is all about storing water and moving water on, in, and above the Earth. Although the atmosphere may not be a great storehouse of water, it is the superhighway used to move water around the globe. Evaporation and transpiration change liquid water into vapor, which ascends into the atmosphere due to rising air currents. Cooler temperatures aloft allow the vapor to condense into clouds and strong winds move the clouds around the world until the water falls as precipitation to replenish the earthbound parts of the water cycle. About 90 percent of water in the atmosphere is produced by evaporation from water bodies, while the other 10 percent comes from transpiration from plants.
There is always water in the atmosphere. Clouds are, of course, the most visible manifestation of atmospheric water, but even clear air contains water—water in particles that are too small to be seen. One estimate of the volume of water in the atmosphere at any one time is about 3,100 cubic miles (mi3) or 12,900 cubic kilometers (km3). That may sound like a lot, but it is only about 0.001 percent of the total Earth's water volume of about 332,500,000 mi3 (1,385,000,000 km3), as shown in the table below. If all of the water in the atmosphere rained down at once, it would only cover the ground to a depth of 2.5 centimeters, about 1 inch.
How much does a cloud weigh?
Image of a cloud being weighed on a kitchen scale. Do you think clouds have any weight? How can they, if they are floating in the air like a balloon filled with helium? If you tie a helium balloon to a kitchen scale it won't register any weight, so why should a cloud? To answer this question, let me ask if you think air has any weight—that is really the important question. If you know what air pressure and a barometer are, then you know that air does have weight. At sea level, the weight (pressure) of air is about 14 ½ pounds per square inch (1 kilogram per square centimeter).
Since air has weight it must also have density, which is the weight for a chosen volume, such as a cubic inch or cubic meter. If clouds are made up of particles, then they must have weight and density. The key to why clouds float is that the density of the same volume of cloud material is less than the density of the same amount of dry air. Just as oil floats on water because it is less dense, clouds float on air because the moist air in clouds is less dense than dry air.
We still need to answer the question of how much a cloud weighs. For an example, let's use your basic "everyday" cloud—the cumulus cloud with a volume of about 1 cubic kilometer (km) located about 2 km above the ground. In other words, it is a cube about 1 km on each side. The National Oceanic and Atmospheric Administration (NOAA) provides some estimates of air and cloud density and weight. NOAA found that dry air has a density of about 1.007 kilograms/cubic meter (kg/m3) and the density of the actual cloud droplets is about 1.003 kg/m3. In the final calculations, the 1 km3 cumulus cloud weighs a whopping 2.211 billion pounds (1.003 billion kilograms)! However, remember that air also has mass, so the cloud floats because the weight of the same volume of dry air is even more, about 2.220 billion pounds (1.007 billion kilograms). So, it is the lesser density of the cloud that allows it to float on the dryer and more-dense air.
The water cycle is all about storing water and moving water on, in, and above the Earth. Although the atmosphere may not be a great storehouse of water, it is the superhighway used to move water around the globe. Evaporation and transpiration change liquid water into vapor, which ascends into the atmosphere due to rising air currents. Cooler temperatures aloft allow the vapor to condense into clouds and strong winds move the clouds around the world until the water falls as precipitation to replenish the earthbound parts of the water cycle. About 90 percent of water in the atmosphere is produced by evaporation from water bodies, while the other 10 percent comes from transpiration from plants.
There is always water in the atmosphere. Clouds are, of course, the most visible manifestation of atmospheric water, but even clear air contains water—water in particles that are too small to be seen. One estimate of the volume of water in the atmosphere at any one time is about 3,100 cubic miles (mi3) or 12,900 cubic kilometers (km3). That may sound like a lot, but it is only about 0.001 percent of the total Earth's water volume of about 332,500,000 mi3 (1,385,000,000 km3), as shown in the table below. If all of the water in the atmosphere rained down at once, it would only cover the ground to a depth of 2.5 centimeters, about 1 inch.
How much does a cloud weigh?
Image of a cloud being weighed on a kitchen scale. Do you think clouds have any weight? How can they, if they are floating in the air like a balloon filled with helium? If you tie a helium balloon to a kitchen scale it won't register any weight, so why should a cloud? To answer this question, let me ask if you think air has any weight—that is really the important question. If you know what air pressure and a barometer are, then you know that air does have weight. At sea level, the weight (pressure) of air is about 14 ½ pounds per square inch (1 kilogram per square centimeter).
Since air has weight it must also have density, which is the weight for a chosen volume, such as a cubic inch or cubic meter. If clouds are made up of particles, then they must have weight and density. The key to why clouds float is that the density of the same volume of cloud material is less than the density of the same amount of dry air. Just as oil floats on water because it is less dense, clouds float on air because the moist air in clouds is less dense than dry air.
We still need to answer the question of how much a cloud weighs. For an example, let's use your basic "everyday" cloud—the cumulus cloud with a volume of about 1 cubic kilometer (km) located about 2 km above the ground. In other words, it is a cube about 1 km on each side. The National Oceanic and Atmospheric Administration (NOAA) provides some estimates of air and cloud density and weight. NOAA found that dry air has a density of about 1.007 kilograms/cubic meter (kg/m3) and the density of the actual cloud droplets is about 1.003 kg/m3. In the final calculations, the 1 km3 cumulus cloud weighs a whopping 2.211 billion pounds (1.003 billion kilograms)! However, remember that air also has mass, so the cloud floats because the weight of the same volume of dry air is even more, about 2.220 billion pounds (1.007 billion kilograms). So, it is the lesser density of the cloud that allows it to float on the dryer and more-dense air.
Global distribution of atmospheric water
| Water source | Water volume, in cubic miles | Water volume, in cubic kilometers | Percent of total freshwater | Percent of total water |
|---|---|---|---|---|
| Atmosphere | 3,094 | 12,900 | 0.04% | 0.001% |
| Total global fresh water | 8,404,000 | 35,030,000 | 100% | 2.5% |
| Total global water | 332,500,000 | 1,386,000,000 | -- | 100% |
Sunday, May 17, 2009
Acid Rain Causes and Effects
What is Acid Rain?
Acid rain is rain that has been made acidic by certain pollutants in the air. Acid rain is a type of acid deposition, which can appear in many forms. Wet deposition is rain, sleet, snow, or fog that has become more acidic than normal. Dry deposition is another form of acid deposition, and this is when gases and dust particles become acidic. Both wet and dry deposition can be carried by the wind, sometimes for very long distances. Acid deposition in wet and dry forms falls on buildings, cars, and trees and can make lakes acidic. Acid deposition in dry form can be inhaled by people and can cause health problems in some people.What is acidity?
Acidic and basic are two ways that we describe chemical compounds. Acidity is measured using a pH scale. A pH scale runs from zero (the most acidic) to 14 (the most basic or alkaline). A substance that is neither basic or acidic is called "neutral", and this has a pH of 7.
What Causes Acid Rain?
Sources of Acid Rain
Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain. Sulfur dioxide and nitrogen oxides dissolve very easily in water and can be carried very far by the wind. As a result, the two compounds can travel long distances where they become part of the rain, sleet, snow, and fog that we experience on certain days.
Human activities are the main cause of acid rain. Over the past few decades, humans have released so many different chemicals into the air that they have changed the mix of gases in the atmosphere. Power plants release the majority of sulfur dioxide and much of the nitrogen oxides when they burn fossil fuels, such as coal, to produce electricity. In addition, the exhaust from cars, trucks, and buses releases nitrogen oxides and sulfur dioxide into the air. These pollutants cause acid rain.
Acid Rain is Caused by Reactions in the Environment
Nature depends on balance, and although some rain is naturally acidic, with a pH level of around 5.0, human activities have made it worse. Normal precipitation—such as rain, sleet, or snow—reacts with alkaline chemicals, or non-acidic materials, that can be found in air, soils, bedrock, lakes, and streams. These reactions usually neutralize natural acids. However, if precipitation becomes too acidic, these materials may not be able to neutralize all of the acids. Over time, these neutralizing materials can be washed away by acid rain. Damage to crops, trees, lakes, rivers, and animals can result.
What is being Done?
Now that you know why acid rain is a problem, you might be wondering what’s being done to control it. Regulations and new technologies are helping reduce acid rain.
EPA’s Acid Rain Program
Power plants generate the electricity we use every day. Unfortunately, power plants also produce large amounts of nitrogen oxides and sulfur dioxide—the pollutants that cause acid rain—when they burn fossil fuels, especially coal, to produce energy. Congress passed a law called the Clean Air Act Amendments of 1990, and this law said that EPA should start the Acid Rain Program. The program limits, or puts a cap on, the amount of sulfur dioxide that power plants can release into the air and issues allowances to the power plants to cover their sulfur dioxide emissions. It also reduces the amount of nitrogen oxides that power plants can release.
Reducing Pollution
Scientists have found different ways to reduce the amount of sulfur dioxide released from coal-burning power plants. One option is to use coal that contains less sulfur. Another option is to “wash” the coal to remove some of the sulfur. The power plant can also install equipment called scrubbers, which remove the sulfur dioxide from gases leaving the smokestack. Because nitrogen oxides are created in the process of burning coal and other fossil fuels, some power plants are changing the way they burn coal.
Other Sources of Energy
A great way to reduce acid rain is to produce energy without using fossil fuels. Instead, people can use renewable energy sources, such as solar and wind power. Renewable energy sources help reduce acid rain because they produce much less pollution. These energy sources can be used to power machinery and produce electricity.
Cleaner Cars
Cars and trucks are major sources of the pollutants that cause acid rain. While one car alone does not produce much pollution, all the cars on the road added together create lots of pollution. Therefore, car manufacturers are required to reduce the amount of nitrogen oxides and other pollutants released by new cars. One type of technology used in cars is called a catalytic converter. This piece of equipment has been used for over 20 years to reduce the amount of nitrogen oxides released by cars. Some new cars can also use cleaner fuels, such as natural gas.
Cars that produce less pollution and are better for the environment are often labeled as low emissions vehicles. You can find out which vehicles are low emissions vehicles by looking at EPA’s Green Vehicle Guide.
What Can You Do?
Government agencies and scientists are not the only ones that can take action to stop acid rain. You can become part of the solution, too!
Understand the Problem
The first step you can take to help control acid rain is to understand the problem and its solutions. Now that you have learned about this environmental issue, you can tell others about it. By telling your classmates, parents, and teachers about what you learned on this site, you can help educate them about the problem of acid rain. You CAN make a difference!
Conserve Energy
Since energy production creates large amounts of the pollutants that cause acid rain, one important step you can take is to conserve energy. You can do this in a number of ways:
* Turn off lights, computers, televisions, video games, and other electrical equipment when you're not using them.
* Encourage your parents to buy equipment that uses less electricity, including lights, air conditioners, heaters, refrigerators, and washing machines. Such equipment might have the Energy Star label.
* Try to limit the use of air conditioning.
* Ask your parents to adjust the thermostat (the device used to control the temperature in your home) when you go on vacation.
Minimize the Miles
Driving cars and trucks also produces large amounts of nitrogen oxides, which cause acid rain. To help cut down on air pollution from cars, you can carpool or take public transportation, such as buses and trains. Also, ask your parents to walk or bike with you to a nearby store or friend’s house instead of driving.
Saturday, May 16, 2009
Water Storage Treatment Process
Follow a drop of water from the source through the treatment process. Water may be treated differently in different communities depending on the quality of the water which enters the plant. Groundwater is water located under ground and typically requires less treatment than water from lakes, rivers, and streams.
Stop at each treatment point to show where the water is along the treatment path. You may click on each treatment point on the image for a little information about that treatment point.
Thursday, May 14, 2009
Place where a concentrated discharge of ground water flows at the ground surface
What is a spring?
A spring is a water resource formed when the side of a hill, a valley bottom or other excavation intersects a flowing body of ground water at or below the local water table, below which the subsurface material is saturated with water. A spring is the result of an aquifer being filled to the point that the water overflows onto the land surface. They range in size from intermittent seeps, which flow only after much rain, to huge pools fwith a flow of hundreds of millions of liters per day.
Springs may be formed in any sort of rock, but are more prevalent in limestone and dolomite, which fracture easily and can be dissolved by rainfall that becomes weakly acidic. As the rock dissolves and fractures, spaces can form that allow water to flow. If the flow is horizontal, it can reach the land surface, resulting in a spring.
Spring water is not always clear
Water from springs usually is remarkably clear. Water from some springs, however, may be "tea-colored." This picture shows a natural spring in southwestern Colorado. Its red iron coloring and metals enrichment are caused by ground water coming in contact with naturally occurring minerals present as a result of ancient volcanic activity in the area. In Florida, many surface waters contain natural tannic acids from organic material in subsurface rocks, and the color from these streams can appear in springs. If surface water enters the aquifer near a spring, the water can move quickly through the aquifer and discharge at the spring vent. The discharge of highly colored water from springs can indicate that water is flowing quickly through large channels within the aquifer without being filtered through the limestone.
Thermal springs
Thermal springs are ordinary springs except that the water is warm and, in some places, hot, such as in the bubbling mud springs in Yellowstone National Park, Wyoming. Many thermal springs occur in regions of recent volcanic activity and are fed by water heated by contact with hot rocks far below the surface. Even where there has been no recent volcanic action, rocks become warmer with increasing depth. In such areas water may migrate slowly to considerable depth, warming as it descends through rocks deep in the Earth. If it then reaches a large crevice that offers a path of less resistance, it may rise more quickly than it descended. Water that does not have time to cool before it emerges forms a thermal spring. The famous Warm Springs of Georgia and Hot Springs of Arkansas are of this type. And, yes, warm springs can even coexist with icebergs, as these happy Greenlanders can tell you.
Global water distribution
For a detailed explanation of where Earth's water exists, look at the chart and data table below. By now, you know that the water cycle describes the movement of Earth's water, so realize that the chart and table below represent the presence of Earth's water at a single point in time. If you check back in a thousand or million years, no doubt these numbers will be different!
Notice how of the world's total water supply of about 332.5 million cubic miles of water, over 96 percent is saline. And, of the total freshwater, over 68 percent is locked up in ice and glaciers. Another 30 percent of freshwater is in the ground. Fresh surface-water sources, such as rivers and lakes, only constitute about 22,300 cubic miles (93,100 cubic kilometers), which is about 0.0067 percent of total water. Yet, rivers and lakes are the sources of most of the water people use everyday.
A spring is a water resource formed when the side of a hill, a valley bottom or other excavation intersects a flowing body of ground water at or below the local water table, below which the subsurface material is saturated with water. A spring is the result of an aquifer being filled to the point that the water overflows onto the land surface. They range in size from intermittent seeps, which flow only after much rain, to huge pools fwith a flow of hundreds of millions of liters per day.Springs may be formed in any sort of rock, but are more prevalent in limestone and dolomite, which fracture easily and can be dissolved by rainfall that becomes weakly acidic. As the rock dissolves and fractures, spaces can form that allow water to flow. If the flow is horizontal, it can reach the land surface, resulting in a spring.
Spring water is not always clear
Water from springs usually is remarkably clear. Water from some springs, however, may be "tea-colored." This picture shows a natural spring in southwestern Colorado. Its red iron coloring and metals enrichment are caused by ground water coming in contact with naturally occurring minerals present as a result of ancient volcanic activity in the area. In Florida, many surface waters contain natural tannic acids from organic material in subsurface rocks, and the color from these streams can appear in springs. If surface water enters the aquifer near a spring, the water can move quickly through the aquifer and discharge at the spring vent. The discharge of highly colored water from springs can indicate that water is flowing quickly through large channels within the aquifer without being filtered through the limestone.
Thermal springs
Thermal springs are ordinary springs except that the water is warm and, in some places, hot, such as in the bubbling mud springs in Yellowstone National Park, Wyoming. Many thermal springs occur in regions of recent volcanic activity and are fed by water heated by contact with hot rocks far below the surface. Even where there has been no recent volcanic action, rocks become warmer with increasing depth. In such areas water may migrate slowly to considerable depth, warming as it descends through rocks deep in the Earth. If it then reaches a large crevice that offers a path of less resistance, it may rise more quickly than it descended. Water that does not have time to cool before it emerges forms a thermal spring. The famous Warm Springs of Georgia and Hot Springs of Arkansas are of this type. And, yes, warm springs can even coexist with icebergs, as these happy Greenlanders can tell you.Global water distribution
For a detailed explanation of where Earth's water exists, look at the chart and data table below. By now, you know that the water cycle describes the movement of Earth's water, so realize that the chart and table below represent the presence of Earth's water at a single point in time. If you check back in a thousand or million years, no doubt these numbers will be different!
Notice how of the world's total water supply of about 332.5 million cubic miles of water, over 96 percent is saline. And, of the total freshwater, over 68 percent is locked up in ice and glaciers. Another 30 percent of freshwater is in the ground. Fresh surface-water sources, such as rivers and lakes, only constitute about 22,300 cubic miles (93,100 cubic kilometers), which is about 0.0067 percent of total water. Yet, rivers and lakes are the sources of most of the water people use everyday.
| Water source | Water volume, in cubic miles | Water volume, in cubic kilometers | Percent of freshwater | Percent of total water |
|---|---|---|---|---|
| Oceans, Seas, & Bays | 321,000,000 | 1,338,000,000 | -- | 96.5 |
| Ice caps, Glaciers, & Permanent Snow | 5,773,000 | 24,064,000 | 68.7 | 1.74 |
| Groundwater | 5,614,000 | 23,400,000 | -- | 1.7 |
| Fresh | 2,526,000 | 10,530,000 | 30.1 | 0.76 |
| Saline | 3,088,000 | 12,870,000 | -- | 0.94 |
| Soil Moisture | 3,959 | 16,500 | 0.05 | 0.001 |
| Ground Ice & Permafrost | 71,970 | 300,000 | 0.86 | 0.022 |
| Lakes | 42,320 | 176,400 | -- | 0.013 |
| Fresh | 21,830 | 91,000 | 0.26 | 0.007 |
| Saline | 20,490 | 85,400 | -- | 0.006 |
| Atmosphere | 3,095 | 12,900 | 0.04 | 0.001 |
| Swamp Water | 2,752 | 11,470 | 0.03 | 0.0008 |
| Rivers | 509 | 2,120 | 0.006 | 0.0002 |
| Biological Water | 269 | 1,120 | 0.003 | 0.0001 |
| Total | 332,500,000 | 1,386,000,000 | - | 100 |
Wednesday, May 13, 2009
Fresh Water Storage
One part of the water cycle that is obviously essential to all life on Earth is the freshwater existing on the land surface. Just ask your neighbor, a tomato plant, a trout, or that pesky mosquito. Surface water includes the streams (of all sizes, from large rivers to small creeks), ponds, lakes, reservoirs and canals (man-made lakes and streams), and freshwater wetlands. The definition of freshwater is water containing less than 1,000 milligrams per liter of dissolved solids, most often salt.
As a part of the water cycle, Earth's surface-water bodies are generally thought of as renewable resources, although they are very dependent on other parts of the water cycle. The amount of water in our rivers and lakes is always changing due to inflows and outflows. Inflows to these water bodies will be from precipitation, overland runoff, ground-water seepage, and tributary inflows. Outflows from lakes and rivers include evaporation and discharge to ground water. Humans get into the act also, as people make great use of surface water for their needs. So, the amount and location of surface water changes over time and space, whether naturally or with human help. Certainly during the last ice age when glaciers and snowpacks covered much more land surface than today, life on Earth had to adapt to different hydrologic conditions than those which took place both before and after. And the layout of the landscape certainly was different before and after the last ice age, which influenced the topographical layout of many surface-water bodies today. Glaciers are what made the Great Lakes not only "great, " but also such a huge storehouse of freshwater.
Surface water keeps life going
Satellite picture of lights in southern Europe and North Africa at night, with the lights along the Nile Delta circled for emphasis. As this picture of the Nile Delta in Egypt shows, life can even bloom in the desert if there is a supply of surface water (or ground water) available. Water on the land surface really does sustain life, and this is as true today as it was millions of years ago. I'm sure dinosaurs held their meetings at the local watering hole 100 million years ago, just as antelopes in Africa do today. And, since ground water is supplied by the downward percolation of surface water, even aquifers are happy for water on the Earth's surface. You might think that fish living in the saline oceans aren't affected by freshwater, but, without freshwater to replenish the oceans they would eventually evaporate and become too saline for even the fish to survive.
As we said, everybody and every living thing congregates and lives where they can gain access to water, especially freshwater. Just ask the 6 billion people living on Earth! Here's a satellite picture of the Mediterranean region during night (the full picture of the Earth is available from NASA). The most obvious thing you can see is that people live near the coasts, which, of course, is where water, albeit saline, is located. But the interesting thing in this picture are the lights following the Nile River and Nile Delta in Egypt ( the circled area). In this dry part of the world, surface-water supplies are essential for human communities. And if you check the price of lakefront property in your part of the world, it probably sells for much more than other land.
Usable fresh surface water is relatively scarce
To many people, streams and lakes are the most visible part of the water cycle. Not only do they supply the human population, animals, and plants with the freshwater they need to survive, but they are great places for people to have fun. You might be surprised at how little of Earth's water supply is stored as freshwater on the land surface, as shown in the diagram and table below. Freshwater represents only about three percent of all water on Earth and freshwater lakes and swamps account for a mere 0.29 percent of the Earth's freshwater. Twenty percent of all fresh surface water is in one lake, Lake Baikal in Asia. Another twenty percent (about 5,500 cubic miles (about 23,000 cubic kilometers)) is stored in the Great Lakes. Rivers hold only about 0.006 percent of total freshwater reserves. You can see that life on Earth survives on what is essentially only a "drop in the bucket" of Earth's total water supply! People have built systems, such as large reservoirs and small water towers (like this one in South Carolina, created to blend in with the peach trees surrounding it) to store water for when they need it. These systems allow people to live in places where nature doesn't always supply enough water or where water is not available at the time of year it is needed.
| Water source | Water volume, in cubic miles | Water volume, in cubic kilometers | Percent of freshwater | Percent of total water |
|---|---|---|---|---|
| Lakes, swamps | 24,600 | 102,500 | 0.29% | 0.008% |
| Rivers | 509 | 2,120 | 0.006% | 0.0002% |
| Total global fresh water | 8,404,000 | 35,030,000 | 100% | 2.5% |
| Total global water | 332,500,000 | 1,386,000,000 | -- | 100% |
| Source: Gleick, P. H., 1996: Water resources. In Encyclopedia of Climate and Weather, ed. by S. H. Schneider, Oxford University Press, New York, vol. 2, pp.817-823. | ||||
Tuesday, May 12, 2009
Water storage in oceans: Saline Water existing in Oceans and Inland Seas
The ocean as a storehouse of water
The water cycle sounds like it is describing how water moves above, on, and through the Earth ... and it does. But, in fact, much more water is "in storage" for long periods of time than is actually moving through the cycle. The storehouses for the vast majority of all water on Earth are the oceans. It is estimated that of the 332,500,000 cubic miles (mi3) (1,386,000,000 cubic kilometers (km3)) of the world's water supply, about 321,000,000 mi3 (1,338,000,000 km3) is stored in oceans. That is about 96.5 percent. It is also estimated that the oceans supply about 90 percent of the evaporated water that goes into the water cycle.
During colder climatic periods more ice caps and glaciers form, and enough of the global water supply accumulates as ice to lessen the amounts in other parts of the water cycle. The reverse is true during warm periods. During the last ice age glaciers covered almost one-third of Earth's land mass, with the result being that the oceans were about 400 feet (122 meters) lower than today. During the last global "warm spell," about 125,000 years ago, the seas were about 18 feet (5.5. meters) higher than they are now. About three million years ago the oceans could have been up to 165 feet (50 meters) higher.
Oceans in movement
If you have ever been seasick (we hope not), then you know how the ocean is never still. You might think that the water in the oceans moves around because of waves, which are driven by winds. But, actually, there are currents and "rivers" in the oceans that move massive amounts of water around the world. These movements have a great deal of influence on the water cycle. The Kuroshio Current, off the shores of Japan, is the largest current. It can travel between 25 and 75 miles (40 and 121 kilometers) a day, 1-3 miles (1.4-4.8 kilometers) per hour, and extends some 3,300 feet (1,000 meters) deep. The Gulf Stream is a well known stream of warm water in the Atlantic Ocean, moving water from the Gulf of Mexico across the Atlantic Ocean towards Great Britain. At a speed of 60 miles (97 kilometers) per day, the Gulf stream moves 100 times as much water as all the rivers on Earth. Coming from warm climates, the Gulf Stream moves warmer water to the North Atlantic.
The water cycle sounds like it is describing how water moves above, on, and through the Earth ... and it does. But, in fact, much more water is "in storage" for long periods of time than is actually moving through the cycle. The storehouses for the vast majority of all water on Earth are the oceans. It is estimated that of the 332,500,000 cubic miles (mi3) (1,386,000,000 cubic kilometers (km3)) of the world's water supply, about 321,000,000 mi3 (1,338,000,000 km3) is stored in oceans. That is about 96.5 percent. It is also estimated that the oceans supply about 90 percent of the evaporated water that goes into the water cycle.
During colder climatic periods more ice caps and glaciers form, and enough of the global water supply accumulates as ice to lessen the amounts in other parts of the water cycle. The reverse is true during warm periods. During the last ice age glaciers covered almost one-third of Earth's land mass, with the result being that the oceans were about 400 feet (122 meters) lower than today. During the last global "warm spell," about 125,000 years ago, the seas were about 18 feet (5.5. meters) higher than they are now. About three million years ago the oceans could have been up to 165 feet (50 meters) higher.
Oceans in movement
If you have ever been seasick (we hope not), then you know how the ocean is never still. You might think that the water in the oceans moves around because of waves, which are driven by winds. But, actually, there are currents and "rivers" in the oceans that move massive amounts of water around the world. These movements have a great deal of influence on the water cycle. The Kuroshio Current, off the shores of Japan, is the largest current. It can travel between 25 and 75 miles (40 and 121 kilometers) a day, 1-3 miles (1.4-4.8 kilometers) per hour, and extends some 3,300 feet (1,000 meters) deep. The Gulf Stream is a well known stream of warm water in the Atlantic Ocean, moving water from the Gulf of Mexico across the Atlantic Ocean towards Great Britain. At a speed of 60 miles (97 kilometers) per day, the Gulf stream moves 100 times as much water as all the rivers on Earth. Coming from warm climates, the Gulf Stream moves warmer water to the North Atlantic.
Sunday, May 10, 2009
Components of the Water Cycle
What is the water cycle?
I can easily answer that—it is "me" all over! The water cycle describes the existence and movement of water on, in, and above the Earth. Earth's water is always in movement and is always changing states, from liquid to vapor to ice and back again. The water cycle has been working for billions of years and all life on Earth depends on it continuing to work; the Earth would be a pretty stale place to live without it.
Where does all the Earth’s water come from? Primordial Earth was an incandescent globe made of magma, but all magmas contain water. Water set free by magma began to cool down the Earth’s atmosphere, until it could stay on the surface as a liquid. Volcanic activity kept and still keeps introducing water in the atmosphere, thus increasing the surface- and ground-water volume of the Earth.
I can easily answer that—it is "me" all over! The water cycle describes the existence and movement of water on, in, and above the Earth. Earth's water is always in movement and is always changing states, from liquid to vapor to ice and back again. The water cycle has been working for billions of years and all life on Earth depends on it continuing to work; the Earth would be a pretty stale place to live without it.
Where does all the Earth’s water come from? Primordial Earth was an incandescent globe made of magma, but all magmas contain water. Water set free by magma began to cool down the Earth’s atmosphere, until it could stay on the surface as a liquid. Volcanic activity kept and still keeps introducing water in the atmosphere, thus increasing the surface- and ground-water volume of the Earth.
A quick summary of the water cycle
Here is a quick summary of the water cycle. The links in this paragraph go to the detailed Web pages in our Web site for each topic. A shorter summary of each topic can be found further down in this page, though.
The water cycle has no starting point. But, we'll begin in the oceans, since that is where most of Earth's water exists. The sun, which drives the water cycle, heats water in the oceans. Some of it evaporates as vapor into the air. Ice and snow can sublimate directly into water vapor. Rising air currents take the vapor up into the atmosphere, along with water from evapotranspiration, which is water transpired from plants and evaporated from the soil. The vapor rises into the air where cooler temperatures cause it to condense into clouds. Air currents move clouds around the globe, cloud particles collide, grow, and fall out of the sky as precipitation. Some precipitation falls as snow and can accumulate as ice caps and glaciers, which can store frozen water for thousands of years. Snowpacks in warmer climates often thaw and melt when spring arrives, and the melted water flows overland as snowmelt. Most precipitation falls back into the oceans or onto land, where, due to gravity, the precipitation flows over the ground as surface runoff. A portion of runoff enters rivers in valleys in the landscape, with streamflow moving water towards the oceans. Runoff, and ground-water seepage, accumulate and are stored as freshwater in lakes. Not all runoff flows into rivers, though. Much of it soaks into the ground as infiltration. Some water infiltrates deep into the ground and replenishes aquifers (saturated subsurface rock), which store huge amounts of freshwater for long periods of time. Some infiltration stays close to the land surface and can seep back into surface-water bodies (and the ocean) as ground-water discharge, and some ground water finds openings in the land surface and emerges as freshwater springs. Over time, though, all of this water keeps moving, some to reenter the ocean, where the water cycle "ends" ... oops - I mean, where it "begins."
Components of the water cycleThe U.S. Geological Survey (USGS) has identified 16 components of the water cycle:
Thursday, May 7, 2009
Properties of Water
Before we begin looking at the properties of water, maybe you'd like to take our True/False quiz about water properties. Some of the answers may surprise you.
What are the physical and chemical properties of water that make it so unique and necessary for living things? When you look at water, taste and smell it - well, what could be more boring? Pure water is virtually colorless and has no taste or smell. But the hidden qualities of water make it a most interesting subject.
Water's Chemical Properties
You probably know water's chemical description is H2O. As the diagram to the left shows, that is one atom of oxygen bound to two atoms of hydrogen. The hydrogen atoms are "attached" to one side of the oxygen atom, resulting in a water molecule having a positive charge on the side where the hydrogen atoms are and a negative charge on the other side, where the oxygen atom is. Since opposite electrical charges attract, water molecules tend to attract each other, making water kind of "sticky." As the right-side diagram shows, the side with the hydrogen atoms (positive charge) attracts the oxygen side (negative charge) of a different water molecule. (If the water molecule here looks familiar, remember that everyone's favorite mouse is mostly water, too).
All these water molecules attracting each other mean they tend to clump together. This is why water drops are, in fact, drops! If it wasn't for some of Earth's forces, such as gravity, a drop of water would be ball shaped -- a perfect sphere. Even if it doesn't form a perfect sphere on Earth, we should be happy water is sticky.
Water is called the "universal solvent" because it dissolves more substances than any other liquid. This means that wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, and nutrients.
Pure water has a neutral pH of 7, which is neither acidic nor basic.
Diagram about pH
Water's Physical Properties
o Weight: 61.998 pounds per cubic foot at 100°F
o Weight: 8.33 pounds/gallon, 0.036 pounds/cubic inch
o Density: 1 gram per cubic centimeter (cc) at 39.2°F, 0.95865 gram per cc at 212°F
Here are some water volume comparisons:
1 gallon = 4 quarts = 8 pints = 128 fluid ounces = 231 cubic inches
1 liter = 0.2642 gallons = 1.0568 quart = 61.02 cubic inches
1 million gallons = 3.069 acre-feet = 133,685.64 cubic feet
What are the physical and chemical properties of water that make it so unique and necessary for living things? When you look at water, taste and smell it - well, what could be more boring? Pure water is virtually colorless and has no taste or smell. But the hidden qualities of water make it a most interesting subject.
Water's Chemical Properties
You probably know water's chemical description is H2O. As the diagram to the left shows, that is one atom of oxygen bound to two atoms of hydrogen. The hydrogen atoms are "attached" to one side of the oxygen atom, resulting in a water molecule having a positive charge on the side where the hydrogen atoms are and a negative charge on the other side, where the oxygen atom is. Since opposite electrical charges attract, water molecules tend to attract each other, making water kind of "sticky." As the right-side diagram shows, the side with the hydrogen atoms (positive charge) attracts the oxygen side (negative charge) of a different water molecule. (If the water molecule here looks familiar, remember that everyone's favorite mouse is mostly water, too).
All these water molecules attracting each other mean they tend to clump together. This is why water drops are, in fact, drops! If it wasn't for some of Earth's forces, such as gravity, a drop of water would be ball shaped -- a perfect sphere. Even if it doesn't form a perfect sphere on Earth, we should be happy water is sticky.
Water is called the "universal solvent" because it dissolves more substances than any other liquid. This means that wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, and nutrients.
Pure water has a neutral pH of 7, which is neither acidic nor basic.
Diagram about pH
Water's Physical Properties
- Water is unique in that it is the only natural substance that is found in all three states -- liquid, solid (ice), and gas (steam) -- at the temperatures normally found on Earth. Earth's water is constantly interacting, changing, and in movement.
- Water freezes at 32o Fahrenheit (F) and boils at 212o F (at sea level, but 186.4° at 14,000 feet). In fact, water's freezing and boiling points are the baseline with which temperature is measured: 0o on the Celsius scale is water's freezing point, and 100o is water's boiling point. Water is unusual in that the solid form, ice, is less dense than the liquid form, which is why ice floats.
- Water has a high specific heat index. This means that water can absorb a lot of heat before it begins to get hot. This is why water is valuable to industries and in your car's radiator as a coolant. The high specific heat index of water also helps regulate the rate at which air changes temperature, which is why the temperature change between seasons is gradual rather than sudden, especially near the oceans.
- Water has a very high surface tension. In other words, water is sticky and elastic, and tends to clump together in drops rather than spread out in a thin film. Surface tension is responsible for capillary action, which allows water (and its dissolved substances) to move through the roots of plants and through the tiny blood vessels in our bodies.
- Here's a quick rundown of some of water's properties:
o Weight: 61.998 pounds per cubic foot at 100°F
o Weight: 8.33 pounds/gallon, 0.036 pounds/cubic inch
o Density: 1 gram per cubic centimeter (cc) at 39.2°F, 0.95865 gram per cc at 212°F
Here are some water volume comparisons:
1 gallon = 4 quarts = 8 pints = 128 fluid ounces = 231 cubic inches
1 liter = 0.2642 gallons = 1.0568 quart = 61.02 cubic inches
1 million gallons = 3.069 acre-feet = 133,685.64 cubic feet
Wednesday, May 6, 2009
Who is Responsible Drinking Water Quality?
The Safe Drinking Water Act gives the Environmental Protection Agency (EPA) the responsibility The Safe Drinking Water Act gives the Environmental Protection Agency (EPA) the responsibility for setting national drinking water standards that protect the health of the 250 million people who get their water from public water systems. Other people get their water from private wells which are not subject to Federal Regulations. Since 1974, EPA has set national safety standards for over 80 contaminants that may occur in drinking water.
While EPA and state governments set and enforce standards, local governments and private water suppliers have direct responsibility for the quality of the water that flows to your tap. Water systems test and treat their water, maintain the distribution systems that deliver water to consumers, and report on their water quality to the state. States and EPA provide technical assistance to water suppliers and can take legal action against systems that fail to provide water that meets state and EPA standards.
For more information
- Read Water on Tap: What You Need To Know
- Find out what's going on in your state. Find its drinking water web site through EPA's local drinking water information web site . This site will also help you find information about your drinking water supplier.
- EPA's rules don't apply to water from private wells, but EPA does have some recommendations for people who get water from private wells.
- To learn how EPA sets limits on drinking water contaminants, read Setting Standards for Safe Drinking Water .
- Read the complete Safe Drinking Water Act or a summary of the 1996 Amendments to the Act..
- Each state writes an annual report on its systems' compliance with drinking water rules. EPA compiles and analyzes these reports in its Compliance Report.
Tuesday, May 5, 2009
The Water Cycle Info
Introduction
As seen from space, one of the most unique features of our home planet is the water, in both liquid and frozen forms, that covers approximately 75% of the Earth's surface. Believed to have initially arrived on the surface through the emissions of ancient volcanoes, geologic evidence suggests that large amounts of water have likely flowed on Earth for the past 3.8 billion years, most of its existence. As a vital substance that sets the Earth apart from the rest of the planets in our solar system, water is a necessary ingredient for the development and nourishment of life.
Water, Water, Everywhere
Water is everywhere on Earth and is the only known substance that can naturally exist as a gas, liquid, and solid within the relatively small range of air temperatures and pressures found at the Earth's surface. In all, the Earth's water content is about 1.39 billion cubic kilometers (331 million cubic miles) and the vast bulk of it, about 96.5%, is in the global oceans. Approximately 1.7% is stored in the polar icecaps, glaciers, and permanent snow, and another 1.7% is stored in groundwater, lakes, rivers, streams, and soil. Finally, a thousandth of 1% exists as water vapor in the Earth's atmosphere.
As seen from space, one of the most unique features of our home planet is the water, in both liquid and frozen forms, that covers approximately 75% of the Earth's surface. Believed to have initially arrived on the surface through the emissions of ancient volcanoes, geologic evidence suggests that large amounts of water have likely flowed on Earth for the past 3.8 billion years, most of its existence. As a vital substance that sets the Earth apart from the rest of the planets in our solar system, water is a necessary ingredient for the development and nourishment of life.
Water, Water, Everywhere
Water is everywhere on Earth and is the only known substance that can naturally exist as a gas, liquid, and solid within the relatively small range of air temperatures and pressures found at the Earth's surface. In all, the Earth's water content is about 1.39 billion cubic kilometers (331 million cubic miles) and the vast bulk of it, about 96.5%, is in the global oceans. Approximately 1.7% is stored in the polar icecaps, glaciers, and permanent snow, and another 1.7% is stored in groundwater, lakes, rivers, streams, and soil. Finally, a thousandth of 1% exists as water vapor in the Earth's atmosphere.
One estimate of global water distribution:
| Volume | Percent of Total Water | Percent of Fresh Water | |
| Oceans, Seas, & Bays | 1,338,000 | 96.5 | |
| Ice caps, Glaciers, & Permanent Snow | 24,064 | 1.74 | 68.7 |
| Groundwater | 23,400 | 1.7 | - |
| Fresh | (10,530) | (0.76) | 30.1 |
| Saline | (12,870) | (0.94) | - |
| Soil Moisture | 16.5 | 0.001 | 0.05 |
| Ground Ice & Permafrost | 300 | 0.022 | 0.86 |
| Lakes | 176.4 | 0.013 | |
| Fresh | (91.0) | (0.007) | .26 |
| Saline | (85.4) | (0.006) | - |
| Atmosphere | 12.9 | 0.001 | 0.04 |
| Swamp Water | 11.47 | 0.0008 | 0.03 |
| Rivers | 2.12 | 0.0002 | 0.006 |
| Biological Water | 1.12 | 0.0001 | 0.003 |
| Total | 1,385,984 | 100.0 | |
Source: Gleick, P. H., 1996: Water resources. In Encyclopedia of Climate and Weather, ed. by S. H. Schneider, Oxford University Press, New York, vol. 2, pp.817-823.
Estimates of groundwater are particularly difficult and vary widely amongst sources, with the value in this table being near the high end of the range. Using the values in this table, groundwater constitutes approximately 30% of fresh water, whereas ice (including ice caps, glaciers, permanent snow, ground ice, and permafrost) constitute approximately 70% of fresh water. With other estimates, groundwater is sometimes listed as 22% and ice as 78% of fresh water.
Monday, May 4, 2009
Solar Water Heating System
Like solar collectors, solar water heaters can be either passive or active. Passive systems have no moving parts, no external energy source except the sun, and rely on the basic principle of physics that hot water rises and cold water falls. Active systems utilize a mechanical circulating pump and some type of temperature control.
A simple passive solar water heater consists of a water tank that has been painted black and placed in a well-insulated box that has glass or plastic on one side. The sun’s rays penetrate the glass and heat the tank. This type of system is often called a “bread box” or batch heater. It allows cold water to flow in at the bottom and hot water to flow out from the top. The system operates on water pressure from the water supply. Water from the system is then transferred to a conventional gas or electric water heater. A thermostat on the water heater determines whether the water is hot enough to be used. If it is not, the conventional water heater adds the required heat.
A simple passive solar water heater consists of a water tank that has been painted black and placed in a well-insulated box that has glass or plastic on one side. The sun’s rays penetrate the glass and heat the tank. This type of system is often called a “bread box” or batch heater. It allows cold water to flow in at the bottom and hot water to flow out from the top. The system operates on water pressure from the water supply. Water from the system is then transferred to a conventional gas or electric water heater. A thermostat on the water heater determines whether the water is hot enough to be used. If it is not, the conventional water heater adds the required heat.
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