Wastewater Management

Wastewater
Wastewater

Wastewater is any water that requires cleaning after it is used. This includes water that has been used for laundry, bathing, dishwashing, toilets, garbage disposals, and industrial purposes. Wastewater also includes rainwater that has accumulated pollutants as it runs into oceans, lakes, and rivers. Pollutants are unwanted chemicals or materials that contaminate air, soil, and water.

The goal of wastewater management is to clean and protect water. This means that water must be clean enough so that it can be used by people for drinking and washing, and by industry for commercial purposes. It also must be clean enough to release into oceans, lakes, and rivers after it has been used.

Wastewater is usually divided into two major groups: point source wastewater and non-point source wastewater. Point source wastewater includes wastewaters that enter natural waters (such as lakes, rivers, and oceans) from defined locations. The most common point sources are sanitary sewers and storm drains.

Wave Energy

Wave Energy
Wave Energy

The oceans store large amounts of kinetic (moving) energy from the wind. The wind generates waves as it blows across the sea’s) surface. The larger the wave, the more energy the wave contains. Wave energy provides a continuous source of renewable, non-polluting energy that can be converted to electricity at wave power plant sites around the world.

Where the waves are

Windy coastlines around large oceans are the best places to build power plants that harness wave energy. Strong winds that blow continuously over long stretches of open water create the largest waves, which contain the most energy. Strong, steady winds that blow in Earth’s major wind belts (zones of wind in a prevailing direction) generate massive waves.

In the subtropical zone on either side of the equator (imaginary circle around Earth halfway between the North and South Poles), suitable wind power sites are along east-facing coastlines in the path of the westerly trade winds, such as the east coast of Florida. (Winds are named for the direction from which they blow; the trade winds are strong winds that blow from east to west in the subtropics on either side of the equator.)

Aquariums

Aquarium
Aquarium

An aquarium is any water-filled tank, pool, or pond in which fish, underwater plants, or animals are kept. An aquarium can be as small as a glass bowl for a goldfish and as large as a pool for a whale or a marine museum.

History of fish keeping

The ancient Sumarians (2500 b.c.e.) were the earliest fish keepers. Fish keeping developed as a way to provide and store food. Fish were caught in rivers and then kept in small ponds until they were used. The ancient Egyptians also kept fish in ponds, but not all of their ponds served a practical purpose. Egyptian hieroglyphs (a system of writing that used symbols and pictures) and art depict fish and fishponds as decorative objects.

In ancient Iran, China, and Japan, fish keepers bred special types of fish for use in decorative ponds. Fish keepers created koi, a popular decorative fish, by selectively breeding carp (a fish used for food) in pleasing colors and sizes. The present-day common goldfish, a close relative of the koi, is also a result of these ancient breeding practices.

Ecology

Ecology
Ecology

Ecology is the study of the relationships between organisms and the relationships between organisms and their environment. Ecology was first recognized as an academic subject in 1869 when German naturalist Ernst Haeckel (1834-1919) first coined the term ecology. The word is derived from the Greek words eco, meaning "house" and logy, meaning "to study," indicating that ecology is the study of organisms in their home.

Ecologists often distinguish between two parts of environment as a whole: the living or biotic part and the nonliving or abiotic part. The biotic part of the environment includes all organisms such as animals, plants, bacteria, and fungi.

The abiotic part includes all physical features like temperature, humidity, availability of light, as well as chemical components, such as the concentrations of salts, nutrients, and gases. Ecology, then, is the study of the relationships between and among the biotic and abiotic environments.

Hydrology and Hydrogeology

Hydrologists and hydrogeologists are water scientists who study the properties of freshwater and its distribution on the continents. (Oceanographers study the physical and chemical properties of salt water in the oceans.)

Together, hydrology and hydrogeology provide information on how to manage and protect freshwater, humans most essential natural resource. Hydrology and hydrogeology are distinct fields of study that employ different methods and techniques, but they overlap to provide a complete picture of Earth’s freshwater resources.

Hydrology is a branch of engineering that deals with the physical properties of surface freshwater, such as lakes and rivers, and with its chemical interactions with other substances. Hydrogeology is a subfield of geology (study of Earth) that, by definition, specifically addresses groundwater—water moving through tiny openings in rock and soil layers beneath the land surface.

In practice, ground and surface water interact as a single system. Surface water seeps into the ground and groundwa-ter emerges to the surface. Hydrogeologists work to explain the geological effects of surface water in rivers, streams and lakes, and hydrologists lend their technical expertise to the mechanics and chemistry of moving groundwater.

Limnology

Limnology
Limnology

Limnology is the study of the chemistry, biology, geology, and physics of waters that are found within continents. In contrast, oceanography is the study of open ocean waters. Waters found within continents may be lakes, reservoirs, rivers, or wetlands (land where water covers the surface for at least part of the year) Although most limnologists specialize in freshwaters, the study of saline lakes, like the Great Salt Lake, also falls under the discipline of limnology.

One of the more important goals of limnology is providing guidelines for water management and water pollution control. Limnologists also study ways to protect the wildlife that lives in lakes and rivers as well as the lakes and rivers themselves. Some limnologists are working on construction of artificial wetlands, which could serve as habitats for a variety of animal and plant species and aid in decreasing water pollution.

History of limnology

Limnology is a relatively new academic subject. Frangois-Alphonse Forel (1841-1912), considered the father of limnology, was a Swiss physician who dedicated much of his life to the study of the biology, chemistry, and physics of Lake Geneva. Around 1868, he coined the term limnology to mean the study of lakes. (The root word limn means "lake" and ology means "the study of.")

Marine Archaeology

Marine Archaeology
Marine Archaeology

Many of the most famous archaeological sites are those of the ancient Egyptians, Greeks, Romans, and Vikings. While most all of these archaeological sites, from Egypt’s pyramids to Rome’s Coliseum, are on land, these cultures had strong ties to the sea, engaging in frequent trade and exploration. They also used ships in wars.

These civilizations left behind shipwrecks and the ruins of port cities that have been claimed by the sea due to erosion (wearing away of land). Technological advances in the late twentieth century permitted archaeologists to begin exploration and excavation of underwater archaeological sites. This branch of archaeology is called marine or underwater archaeology.

Archaeology explores how people lived in the past through excavation and survey. An excavation is a planned, careful exploration of ancient sites. It is sometime called a dig because digging (excavation) is the most well known method for discovering clues about the past at an archeological site. Wherever people live or work, they leave traces of their life.

Marine Biology

Marine Biology
Marine Biology

Marine (ocean) biology is the study of the function, biodiversity, and ecology of the animals and plants that live in the ocean. An organism’s function is how it lives and grows in its environment. Biodiversity refers to the wide range of species of plants, animals, and microorganisms such as bacteria that live in the ocean.

Ecology is the study of the relationships between organisms as well as the relationships between organisms and their environment. In order to do their work, marine biologists incorporate information and techniques from a broad range of disciplines, including chemistry, physics, geology (the study of rocks), paleontology (the study of fossils), and geography (the study of locations on Earth).

Many factors make the marine environment a unique place for animals and plants to live. The marine environment is fluid, which affects the way organisms move and breathe. A variety of chemicals are dissolved in the water that bathes marine organisms and many have special ways to use these chemicals or to prevent them from entering their bodies. Ocean water is salty, which affects the organism’s ability to obtain and hold water in its body.

Marine Geology and Geophysics

Marine Geology and Geophysics - California's central coast, just north of Pismo Beach
Marine Geology and Geophysics

Marine geology and geophysics are scientific fields that are concerned with solving the mysteries of the seafloor and Earth’s interior. Marine geologists, like all geologists, seek to understand the processes and history of the solid Earth, but their techniques differ from geologists who work on land because they study geologic (Earth’s) features that are underwater.

The oceans cover more than 70% of Earth, and water obscures a wealth of information about the rocks and sediments (particles of rock, sand, and other material) in the ocean basins. Marine geologists rely mainly on physical techniques to uncover the features and processes of the seafloor.

Geophysicists are scientists who study the physical properties of the solid Earth, and often work closely with marine geologists. Geophysicists use experiments and observations to determine how Earth materials such as rock, magma (molten rock), sediments, air, and water affect physical phenomena such as sound, heat, light, magnetic fields (a field of magnetic force), and earthquake tremors (seismic waves).

Oceanography

Oceanography
Oceanography

Oceanography, also called marine science, is the study of the ocean. Its goal is to discover unifying principles that can explain data measured in ocean waters, in the organisms that live in the ocean, and on the land surrounding the ocean. Oceanography is a broad subject, drawing on techniques and theories from biology, chemistry, physics, mathematics, geology, and engineering.

Oceanography is usually divided into four different areas of research. Marine biology or biological oceanography focuses on life (animals, plants, and bacteria) in the ocean. Chemical oceanography studies the substances that are dissolved in the ocean.

Physical oceanography attempts to understand the movement of water and the relationships between oceans and the atmosphere (mass of air surrounding Earth). Marine geology is directed at understanding geological features of the ocean floor, such as the composition of the seafloor and the movement of tectonic plates (moving plates of Earth’s crust).

Remote Sensing

Remote sensing
Remote sensing

Remote sensing is a technique that gives information about the surface of the Earth and the underwater world without touching the surface. The technique bounces energy off of nonliving or living objects and analyzes the returning signal to collect information.

Remote sensing has many uses in water. Common uses of remote sensing include charting the depth of a lake or ocean bottom. It is vital to the fishing industry and in locating objects at the bottom of the water. Treasure hunters and researchers would find it much harder to detect lost shipwrecks if not for remote sensing.

People interested in finding out where water pollution is occurring can take remote sensing images of water from planes or satellites (orbiting spacecraft) to detect microorganisms such as algae that thrive in polluted water. People who are trying to find deposits of oil and natural gas under the ocean floor also use remote sensing.

Agricultural Water Use

Agricultural Water Use
Agricultural Water Use

The images of seemingly endless crop fields of the American Midwest and the lush San Joaquin Valley of central California are powerful symbols of the agricultural might of the United States. In the past century, the United States has become the greatest producer of food in the world.

Water has always been a vital part of agriculture. Just like humans, crops need water to survive and grow. The process where dry land or crops are supplied with water is called irrigation. A century ago, the relatively small fields of a local farmer in many areas of the United States could receive enough moisture from rainwater, along with water that could be diverted from local streams, rivers, and lakes.

The growth of huge corporate farms that are thousands of acres in size has taken the need for water to another scale. For these operations, water needs to be trucked in, pumped up from underground, and obtained from surface water (freshwater located on the surface) sources in large quantities.

Aquaculture

Aquaculture
Aquaculture

Aquaculture is the farming of animals or plants under controlled conditions in aquatic environments. Aquaculture usually refers to growing animals and plants in fresh or brackish water (water that has a salt content between that of freshwater and that of ocean water). Mariculture indicates the farming of animals and plants in ocean waters. (Marine means seawater.)

Just as on land, aquaculture and mariculture farmers try to control the environmental factors surrounding their crops in order to make them grow quickly and in good health. Some of the factors that aquaculture and mariculture farmers manipulate are the diet of their animals, the nutrients provided to their plants, the reproductive cycles of both animals and plants, and the chemistry and physical properties of the water where the farms are located.

They also try to develop methods to minimize diseases in their crops, to keep their crops safe from predators (animals that hunt them for food), and to reduce the pollution produced by their crops.

Commercial and Industrial Uses of Water

Waterpark
Waterpark

Besides being vital for human survival, water is also necessary in commerce and in industry. Commercial operations are those that generally do not manufacture a product, but provide a service, such as hospitals, restaurants, and schools. Industry usually involves manufacturing a product.

In industry, water helps keep machinery needed for the making of products running smoothly and efficiently. Water can also be a vital part of the product, such as in sports drinks or soft drinks. In the United States, the total amount of fresh and salt water used every day by industry is nearly 410 billion gallons.

To illustrate such a huge number, think of that amount of water in terms of weight. A gallon of water weighs a little over 8 pounds (3.6 kilograms). The daily water usage in the United States totals almost 3.5 trillion pounds (1.6 trillion kilograms), about the same as 200 million 200-pound (90.7 kilogram) people!

Economic Uses of Groundwater

Groundwater in Burkina Faso, Africa
Groundwater in Burkina Faso, Africa

Groundwater is one of humans’ most valuable natural resources. Groundwater is the water contained in the rock and soil layers beneath Earth’s surface, and it makes up most of Earth's supply of fresh, liquid water. (The oceans and ice in the North and South Poles contain 99% of Earth's total water supply. Groundwater accounts for almost all of the remaining 1%.)

Throughout history, humans have settled in areas with plentiful and pure groundwater, and have fought to own and protect wells and springs. Today, human water needs in many arid (dry) or heavily populated regions far exceed surface water supplies. Earth’s rapidly-growing human population is becoming increasingly reliant on groundwater.

Groundwater fills wells and city water supplies. Ground-water irrigates (waters) crops, feeds livestock, and produces farm-raised fish. Groundwater is used to cool nuclear reactors that generate electricity, mix concrete, and manufacture millions of consumer products. In short, groundwater plays a vital role in almost every facet of people’s lives, from drinking water, foods, and products people buy to roads and the buildings in which people live and work.

Minerals and Mining

Traditional gold mining
Traditional gold mining

Minerals are defined as naturally occurring solids found in the earth that are composed of matter other than plants or animals. Ore is a naturally occurring source of minerals, such as a rock. A mineral can be composed from one element, such as diamond, which contains only carbon, or several elements, such as quartz, which contains silicon and oxygen. An element is a substance that cannot be divided by ordinary chemical means.

Even ice is considered a mineral. Minerals are found everywhere on Earth, from the bottom of the ocean to the highest mountains. Mineral deposits are frequently located underground, and thus they must be mined. South Africa and Russia hold the largest amount of minerals in the world. Minerals are vital to people’s lives, and many of these minerals are critical to countries’ industries and economies.

The United States is relatively poor in critical minerals, including platinum, cobalt, and gold, but there are sand deposits of titanium ore in Florida and the Pacific Northwest. In the central United States, minerals that contain lead and gallium (used in computer chips) are abundant, and iron ore is found in the states near the Great Lakes. Most of the diamonds are mined in Africa, as is gold, although gold is found in many other locations as well.

Municipal Water Use

Drinking tap water
Drinking tap water

Many people live in municipalities (cities, towns, and villages with services such as water treatment, police, and fire department). One benefit of living in a municipality is that potable water (water safe to drink) is usually available at any time by turning on the tap. Part of the responsibility of citizens and municipal officials however, is to manage and protect the local water supply.

If municipal water becomes contaminated, the result can be far-reaching and rapid. Bacteria and viruses in water can spread throughout the underground reservoir of water (the aquifer) or throughout the miles of pipelines that carries water to houses in towns and cities. As well, non-living pollutants such as oil, gasoline and sediment can spread contaminate water.

The results of such contamination can be disastrous. In the summer of 2000, the municipal water supply of Walkerton, a town in the Canadian province of Ontario, became contaminated with a certain type of bacteria called Escherichia coli (or E. coli for short). This type of E. coli caused a serious illness in over a thousand people who drank the town water, and killed seven people.

Petroleum Exploration and Recovery

Oil rig - Petroleum exploration
Oil rig - Petroleum exploration

Petroleum, also called crude oil, is a thick, yellowish black substance that contains a mixture of solid, liquid, and gaseous chemicals called hydrocarbons. Since its discovery as an energy source in the mid-1800s, petroleum has become one of humans’ most valuable natural resources. Petroleum is arguably the single-most important product in the modern global economy.

Hydrocarbons separated (refined) from crude oil provide fuels and products that affect every facet of life in industrialized nations like the United States. Natural gas and propane are gaseous hydrocarbons that are used to heat homes and fuel stoves. Natural gas actually exists as a gas in underground reservoirs (underground rock formations containing oil or natural gas) and is not refined from crude oil, but it is still considered a petroleum product.

The liquid portion of petroleum becomes such essential products as home heating oil, automobile gasoline, lubricating oil for engines and machinery, and fuel for electrical power plants. Asphalt road surfaces, lubricating oils for machinery, and furniture wax are all composed of semi-solid hydrocarbons. Petroleum products are the building blocks of plastics. The hydrocarbon gas ethylene is even used to help ripen fruits and vegetables!

Residential Water Use

Residential Water Use
Residential Water Use

In the United States, approximately 408 billion gallons (1,544 billion liters) of water are used every day! While power production and irrigation (watering crops) consume the majority of water usage, public and self-supply water systems produce 47 billion gallons (178 billion liters) a day for residential users and businesses.

Residential water use includes both indoor and outdoor household water usage. Water is used indoors for showering, flushing toilets, washing clothes, washing dishes, drinking, and cooking. Outdoor water usage includes washing the car, and watering the lawn, pools, and plants.

Public and private water

Nearly 85% of residential water users in the United States receive their water from public supply water systems. A public supply water system is a government facility or private company that collects water from a natural source such as a lake, river, or the ground.

Salt

Natural sea salt
Natural sea salt

Common table salt is a compound. A compound is a chemical substance in which two or more elements are joined together. An element is a substance that cannot be broken down into a simpler substance. Elements, either alone or joined together as compounds, make up every object. The elements sodium and chlorine join together to make table salt.

Sodium is represented by the symbol "Na," and chlorine is represented by the symbol "Cl." Because one atom (smallest unit that has all the chemical and physical characteristics of an element) of sodium joins with one atom of chlorine, table salt is represented by the symbol "NaCl."

The need for salt

All animals, including humans, require salt. Salt is needed to regulate many bodily functions including maintaining a regular heart rhythm, blood pressure, and fluid balance in the body. Additionally, salt is required for nerve cells to communicate efficiently, and for regulating the electrical charges moving into and out of cells during processes such as muscle contraction.

Shipping on Freshwater Waterways

Ancient Egyptian boat replica
Ancient Egyptian boat replica

For thousands of years humans have used freshwater waterways to ship food, building materials, and goods between regions. A freshwater waterway is any low-salt body of water, such as a river, lake, or man-made canal on which ships may travel. The need for freshwater for drinking and irrigation (watering crops) led most early civilizations to develop along rivers.

Shipping on freshwater waterways continues to be a reliable and important way to transport goods. Shipping goods over waterways is slower than other forms of shipping, yet it is less expensive and allows larger loads of cargo. Therefore many heavy raw materials such as coal, oil, timber, food products, and metal are often shipped over water. Many modern cities are still located along rivers and lakes.

Shipping in ancient Egypt

The ancient Egyptians (3000 b.c.e.-30 c.e.) depended upon the Nile River for their survival. The Nile River was the only source of drinking water for most Egyptians. Its yearly floods deposited silt (fine particles smaller than sand) that fertilized Egyptians crops. The Egyptians also used the Nile as their main highway, connecting Upper Egypt in the south with Lower Egypt in the north.

Shipping on the Oceans

Cargo ship on the ocean
Cargo ship on the ocean

Throughout recorded history, humans have relied on the oceans to ship goods quickly and efficiently. Historically, shipping on the oceans had several advantages over shipping over land. Shipping over land required moving bulky and heavy goods over mountains, across deserts, or through forests.

The location of roads often dictated where goods could be shipped. Before vehicles, land travelers also had to carry enough food and water to keep their pack animals alive, adding to the weight of their loads.

Two thousand years ago, the power of the Roman Empire was founded on the economic benefit that Rome gained from its control of trade on the Mediterranean Sea. Most of Rome’s empire lay on the shores of the Mediterranean Sea, which served as a highway for the trade of wine, food, timber, spices, and other valuable materials.

Surface and Groundwater Use

Surface water - Lake Wanaka, New Zealand
Surface water - Lake Wanaka, New Zealand

Surface water is the water that lies on the surface naturally as streams, rivers, marshes, lagoons, ponds, and lakes. Surface water can also be collected and stored in containers that have been built especially for that purpose. These containers are called reservoirs. Fresh water also collects in areas of soil and rock underground. This is groundwater.

Rain falling from the sky and snow melting in the springtime can flow downhill to gather in stream or riverbeds. From there, the water flows to a lake or ocean. In other locations, the rain or melted snow is soaked up by the soil and makes its way further down into the ground because of gravity (the force of attraction between all masses in the universe).

Uses of surface and groundwater

Surface water tends to be used by humans more often than groundwater. This is because it is much easier to obtain surface water. Inserting a pipe or tube into the water and then pumping out the water is all that is needed. Sometimes, if the surface water source is located on a hillside, the water flows through the pipeline because of gravity.

Tourism on the Oceans

Tourism on the Oceans
Tourism on the Oceans

Human interest in the sea fuels a multi-billion dollar a year ocean tourism industry. Ocean tourism refers to pleasure travel in which the sea is the primary focus of activities. Ocean tourism comes in many forms including cruises, ecotourism, and fishing expeditions.

Cruising the oceans

Cruises are one of the most popular forms of ocean tourism. In the late nineteenth and early twentieth century, cruise liners were needed to carry passengers across the oceans. Many of these cruise ships—including the ill-fated Titanic, which sank in 1912 killing over 1,500 people—provided passengers a luxurious way to travel. Originally powered by steam-driven engines, most modern cruise ships use diesel fuel to power their engines.

While cruise ships were needed for Atlantic Ocean crossings, by the mid-twentieth century, air travel made ocean crossings cheaper and faster. An airplane can cross the Atlantic in several hours instead of the one week required by most cruise ships. Cruise lines could no longer promote their services as providing a means of travel to and from vacation. (A cruise line is a company that owns one or more cruise ships.)

Transportation on the Oceans

Transportation on the Oceans - Queen Mary 2 and Queen Elizabeth 2 sailing side-by-side
Transportation on the Oceans

For thousands of years, oceans provided one of the fastest and most valuable forms of transportation. By 3200 b.c.e., Egyptian ships made of reeds (tall, woody grass) used sails to travel along the coast of northern Africa. Over the centuries, ocean-going ships became larger and faster.

Around 1000 b.c.e. the Vikings explored the coast of Canada in sailboats. Spanish ships explored the Americas in the fifteenth and sixteenth centuries. British tall ships carried settlers to the Americas, Asia, Australia, and Africa in the sixteenth through nineteenth centuries.

Until the mid-twentieth century, ships were the only mode of transportation for ocean crossings. The rise of air transportation after 1930 reduced the role of ocean-going vessels in transportation. Airplanes provided a quicker and often cheaper way to move people great distances, which caused the types of vessels and purposes of ocean transportation to change.

Whaling

Whaling
Whaling

Whaling, which is the hunting and killing of whales, is an activity that dates back centuries. Native people like the Macah, Nootka, and Coastal Salish of the Pacific Northwest are known to have hunted whales nearly 2,000 years ago. Whaling became popular with Europeans when they colonized North America in the late 1600s.

By 1672, whaling parties were organized off of Cape Cod in Massachusetts and off of Long Island in New York. However, by the early 1700s, the number of whales that close to shore had already begun to decline, so larger ships called sloops were developed that could capture whales farther off shore.

In the late 1800s, whaling had become a thriving commercial industry. Two of the most commonly hunted whales were the right whale and the sperm whale. The right whale was so named because it was the "right" whale to catch.

Dangerous Waters

Giant whirpool
Giant whirpool

Ever since humans first took to the seas thousands of years ago, sailors have faced numerous dangers. Ancient civilizations tried to explain these dangerous conditions by claiming that they were the work of angry gods or monsters.

While scientific explanations have been advanced for dangerous phenomena such as high waves, hurricanes, and treacherous ocean currents (steady flows of water in a prevailing direction), many lives are still lost in the water each year, mainly due to drowning or hypothermia.

Hypothermia is a condition where the core body temperature becomes too cold to function properly. Prolonged exposure to waters that may initially seem warm, between 70°-80°F (21°-27° C), can cause death from hypothermia.

Recreation in and on Freshwaters

Fishing in freshwater
Fishing in freshwater

Fishing and swimming

Fishing is one of the most popular freshwater activities, with over 44 million anglers (people who fish) in the United States. Fish live in almost every lake, river, and stream in the United States, which makes fishing possible for most Americans.

There are two main types of freshwater fishing: fly fishing and spin fishing. The form of fishing used depends on location, the type of fish, and the body of water. Fly fishing is most popular on rivers and streams. Popular types of fish for freshwater fly fishing include trout, bass, and salmon.

When fly fishing, the weight of the fishing line carries the fly, or lure, out into the stream. A series of arm motions whip the fishing line overhead like a bullwhip, simulating the movement of the prey. Fly fishers lure fish with artificial flies and other artificial water-loving insects that are the natural prey of river fish.

Recreation in and on the Oceans

Beach
Beach

Every year, Americans spend billions of dollars and a large amount of their spare time on recreational activities in and on the oceans. Among others, popular ocean-based activities include swimming, snorkeling, scuba diving, sailing, fishing, and surfing.

In the ocean

Swimming is one of the most popular forms of ocean recreation. Millions of Americans visit the beach every year to swim in the ocean. While swimming, beachgoers participate in snorkeling. Snorkeling, or skin diving, is a form of diving in which the diver swims at or near the surface of the water.

Skin diving is simply holding one’s breath underwater for as long as possible. The diver can remain underwater for long periods by breathing through a snorkel, which is a hollow tube attached to a mouthpiece. The snorkel juts out above the surface of the ocean, allowing the diver to breathe surface air through the snorkel like a straw.

Arid Climates

Arid climates, Old Telegraph Station Hill near Wyndham, Kimberley, Western Australia
Arid climates

An arid climate is one that receives less than 10 inches (25.4 centimeters) of rainfall in an entire year. Deserts are areas that are arid. Although the most familiar image of a desert involves hot sand, the Arctic North and Antarctica are also deserts, as they also receive little moisture, usually in the form of snow.

In contrast, the island of Fiji receives drenching rains for several months of the year, and is located in a tropical area of the world. Fiji receives an astounding 120 inches of rain each year, more than ten times the rainfall that falls in arid areas.

The rain that falls in an arid climate is sporadic and when it does fall, it is usually in the form of a thunderstorm. Flash floods are frequently a danger in arid climates after thunderstorms as the dry, compact soil cannot absorb water quickly enough to capture the rain. Streams swell with water for a few hours and then dry up again until the next cloudburst.

Exploration of the Oceans

Exploration of the Oceans
Exploration of the Oceans

For centuries, exploration of the oceans was primarily limited to exploration on the surface of the oceans. Explorers sailed or rowed ships across the seas in search of new lands or natural resources.

Biological limits prevented humans from exploring beneath the surface. Three main issues prevented humans from exploring great depths of the ocean. First, humans must breathe air to survive, and humans can hold their breath for several minutes or less.

This does not provide much time to dive, explore, and return to the water’s surface. Second, the weight of water increases greatly as a diver descends into deep water. Finally, water temperature decreases with increasing depths. The temperature near the ocean floor is near freezing.

Water and Cultures in the Ancient World

Ancient Egyptian Temple, Island of Philae, Nile River, Egypt
Ancient Egyptian Temple, Island of Philae, Nile River, Egypt

Water was the center of life in many ancient cultures. In Greek mythology, one of the most ancient and powerful gods was Neptune, the god of the sea. Ancient Greek literature, such as The Odyssey by Homer (about 800 b.c.e.), mentions sea monsters, whirlpools, and harrowing voyages upon the sea. In India, the Ganges River was considered sacred from historical accounts over 3000 years old.

To the ancient Egyptian, the Nile River was the political, economic, and life-sustaining center of their kingdom. Without the Nile, Egypt would be as barren as its nearby deserts. Ancient civilizations’ respect for water grew from their absolute need for water. Like today, water sustained life in many ways.

Seafaring in the ancient world

Ancient cities constructed beside the sea based their economies on the nearby water. Fishing, exploration, trade, and warfare necessitated shipbuilding. Shipbuilding was one of the most important crafts of the ancient world.

Water and Cultures in the Modern World

Sidney opera house
Sidney opera house

Water plays an important role in shaping the modern world. Cities are built on water. Humans rely on water for cooking, drinking, washing, transportation, trade, energy, irrigation (watering crops), and recreation.

The use of water in the modern world has also created problems. Population growth and advancements in technology threaten the world’s water supply. Overfishing and pollution stress many of the world’s seas, and shortages of water stress human populations in arid (extremely dry) lands.

Cities and ports

Most cities are located beside water, Coastal areas in particular boast large cities. Eight out of the top ten most populous cities in the world lie on the coast. Nearly 44% of the world’s population lives within 100 miles (161 kilometers) of a coast.

Overuse

Flooding fields with water
Flooding fields with water

In countries like the United States, where some states are dotted with countless lakes and many people live within easy reach of an ocean, it may be easy to assume that drinking and recreational waters are limitless. This is not the case.

In many areas of the world, water is a preciously limited resource and in some cases, water scarcity is the result of human activity. In many countries in which the water supply is scare, water is being used faster than it is being renewed, often for agriculture or to supply water for a growing population.

Agricultural overuse

About 30% of all the freshwater used in the United States and 60% of the world’s available supply of freshwater is used to grow crops. Crops require a large volume of water for production. For example, to produce 2.2 pounds (1 kilogram) of rice requires about a bathtub full of water.

Sediment Contamination

Sediment Contamination
Sediment Contamination

The bottom of streams, rivers, lakes, ponds, mudflats, and even oceans is made up of materials that were deposited there by the natural forces of currents (a constant flow of water in a predominant direction), gravity (attraction between two masses), and flows of incoming streams and rivers. This material, consisting of soil, pebbles, silt, clay and other material, is known as sediment.

Sedimentation (the deposit of sediments) becomes a problem if it is contaminated by toxic (poisonous) chemicals or harmful microorganisms. Just as soil and other material is carried to the bottom of water bodies, harmful chemicals or organisms can collect on the sediments.

The problem of sediment contamination is increasing in many areas throughout the world. The United States Environmental Protection Agency (EPA) conducted a survey across the country in 1998 in which they found hundreds of contaminated sites.

Species Introduction

Species Introduction
Species Introduction

Daily life in most environments, including the watery environments of salty oceans and freshwater streams, rivers, lakes, ponds, and wetlands is a balance between all the living things in the particular environment (ecosystem). Changing the mix of these living things can upset the ecosystem and have undesirable consequences.

Sometimes the change is accidental. A new species (a classification of related organisms that can reproduce) can happen to find its way into a new environment where the conditions include plenty of food, few enemies, and an ideal temperature.

The change can also be deliberate, due to humans’ attempts to control one undesirable species by adding another. Sometimes, the introduced species thrives in the environment and becomes the dominant species.

Water Conservation

Water Conservation

Conservation is the philosophy that natural resources should be used cautiously so that they will remain available for future generations of people. In practice, conservation is the act of protecting, managing, and restoring shared earth resources such as soil, air, forests, minerals, petroleum, wildlife, and water—one of humans’ most essential resources.

Water conservation can be as simple as one person using water sparingly during a drought (prolonged period of dry weather), or as complex as a multi-national committee de veloping a long-term water distribution plan for an entire continent.

The word conservation means different things to different people, and a workable conservation plan for a particular region or resource usually involves a compromise between several interest groups. Consider, for example, a forest. To a logging company, forest conservation means developing a system of cutting and replanting healthy, fast-growing trees that ensures continuing profits.


To a forest ecologist (a person who studies relationship between organisms and their environment) it means restoring a forest to a more natural state that supports a healthy community of plants and animals, along with protecting its most fragile areas and species. To a homeowner conservation means preserving the natural beauty of the forest and safeguarding property from forest fires. And to a preservationist it means letting nature manage the forest with little or no human intervention.

Conservation generally involves managing natural resources to serve people, whether by providing materials for essential needs (water, food, shelter, and energy) and consumer products (cars, clothing, computers, furniture), or simply by protecting wild areas where people can enjoy nature and outdoor recreation.

While most scientists do not argue with using Earth’s natural resources to meet human needs, most scientists also agree with the general idea that shared natural resources should be protected from overuse and pollution, and wisely managed using sound scientific information.

Need for water conservation

Need for water conservation

Water is Earth’s most plentiful natural resource. It covers almost three-quarters of our planet’s surface. Astronauts say Earth looks like a “blue marble” from space with its blue oceans and white swirls of water droplets (clouds) in the atmosphere (mass of air surrounding Earth).

Water is also a renewable resource. Water moves endlessly within the hydrologic cycle, and is almost never destroyed in the process. When humans draw water from lakes, rivers, oceans, or groundwater reservoirs (aquifers), new water replaces it.

Water is even self-cleansing. When it evaporates, it leaves pollution and salts behind and forms clouds that produce fresh rainwater. New water that flows into polluted lakes and rivers acts to dilute (lower the concentration or amount) and disperse (spread out) pollutants.


Why then, if water is so abundant and easily replenished, do people need to conserve it? First, fresh, liquid water that is suitable for human use only makes up a small percentage of Earth’s total water supply. Almost all (97%) of Earth’s water is undrinkable salt water that resides in the oceans.

In addition to being too salty to drink, seawater corrodes (wears away) metals and gums up machinery, making it unsuitable for most other human uses. Much of the remaining 3% is frozen in glaciers (slow moving mass of ice) and ice in the North and South Poles.

Second, fresh water is distributed unevenly on Earth’s surface. Some regions have abundant freshwater resources and others are arid (dry) deserts where water is scarce. Third, though water is a renewable resource in a general sense, local and even regional water supplies can run dry from overuse.

Finally, human activities that add chemical substances to surface water, groundwater and the oceans can pollute water to the extent that it is unsafe for human use and damages the larger ecosystem. For all these reasons, water conservation and management are extremely important, especially in places where a large human population depends on a limited water supply.

Water conservation in history

Roman aqueduct
Roman aqueduct

Humans have shared public water resources since they first settled in permanent villages thousands of years ago. Early peoples however, usually solved water supply or contamination problems by simply moving their villages.

When wells ran dry from overuse, or rivers became polluted with human waste, they just relocated to a new, unspoiled location. Ancient civilizations in the arid Middle East, Africa, and China, who needed to supply water to the residents of large cities and to permanent agricultural lands were the first true water conservationists.

Throughout history societies have succeeded, in part, because of water management plans that ensured a steady supply of unpolluted water through periods of drought (prolonged shortage of rain) and flood. The desert empires of Mesopotamia and Egypt flourished by using elaborate irrigation (crop watering) and plumbing systems to distribute water from the rivers Tigris, Euphrates, and Nile to cities and croplands.

The Ancient Greeks constructed drainage systems and huge stone sewers at the palace of King Minos at Knossos on the island of Crete almost 5,000 years ago. Water engineering was one of the great hallmarks of the Roman Empire.

The Romans built aqueducts, canals, irrigation systems, city sewers, and indoor plumbing throughout their vast empire. (The modern English word plumber comes from the Latin word for lead, plumbus, and the ingenious Roman lead workers, plumberium, who engineered the world’s first reliable indoor plumbing.)

Civilizations and empires have also failed because of poor water conservation practices or water management. Populations that have overused their water supplies or have allowed their water to become polluted have suffered serious consequences. Many archeologists attribute the mysterious disappearance of the Anasazi people from the American Southwest to inadequate water supply.

Diseases caused by poor sanitation and poisoning from lead pipes were ironically, two factors that contributed to the fall of the Roman Empire. Improper waste management has also played a major role in the spread of diseases such as the bubonic plague that killed millions of Europeans during the Middle Ages.

Waterborne diseases such as cholera, typhoid, typhus, and dysentery thrive where sewers bearing waste from infected persons empty into a public water supply. Scientists only began to understand the dangers of microscopic bacteria in sewage-polluted water after an epidemic of cholera killed thousands of people in Europe and the United States in the 1830s.

History of the American conservation movement. The idea of conservation only began to gain popularity in the United States at the end of the 1800s. Until then the North American frontier had provided seemingly inexhaustible natural resources, including abundant fresh water. By the 1890s however, European settlement had reached across the entire continent, and the census of 1890 declared the American frontier closed.

Unrestricted sport hunting had slaughtered the bison herds of the Great Plains and killed off the flocks of passenger pigeons that once migrated (traveled periodically) down the Atlantic coast. Logging, grazing, mining, and hydropower (power from water energy) development threatened America’s most dramatic national landmarks. Niagara Falls, for example, nearly lost its untamed water flow.

The Gilded Age at the end of the nineteenth century was also a time of unregulated resource exploitation and social inequality that made conservation an appealing idea to the general American public and to government leaders. Powerful businessmen of the mining, timber, railroad, and ranching industries became immensely wealthy as they laid waste to America’s pristine forests, prairies, wetlands and waterways. At the same time, most Americans saw their living standards decline.

Without government oversight, laborers, owners of small businesses, and independent settlers were at the mercy of the economically and politically powerful industrialists. While the powerful of the gilded age enjoyed luxurious estates and the diversions of high society, average Americans received low wages, worked in poor conditions, and lived in crowded cities and towns.

Gifford Pinchot (1865–1946) founded the conservation movement in the United States in the late 1890s. Pinchot argued that the best use of nature was to improve the life of common citizens. Pinchot’s ideas were inspired by his observations of environmental destruction and social inequality that resulted from unregulated wilderness exploitation during the 1800s. He was also influenced by the writings of other nineteenth century explorers and naturalists including George Perkins Marsh and John Wesley Powell.

Pinchot had great influence during the presidency of Theodore Roosevelt (1901–9), and he helped to steer conservation policies from the turn of the century until the 1940s. (Roosevelt was an avid hunter and an ardent conservationist in his own right.) Pinchot became the first head of the U.S. National Forest Service when it was established in 1905. Its motto, “The Land of Many Uses” reflects Pinchot’s philosophy.

Conservation efforts have continued in the United States since the era of Roosevelt and Pinchot. Government agencies, groups of private citizens, and even business leaders have developed strategies to protect America’s natural resources. The U.S. government has set aside millions of acres of public land as national forests and parks, and a large group of agencies now manage the nation’s natural resources in a scientifically and economically reasonable manner.

Universities and professional schools offer courses in resource management and natural sciences such as biology and geology. The discipline of ecology, the study of communities of plants and animals that live and interact in a specific environment, blossomed as scientists, engineers, and policy makers sought to understand the natural environments they were charged to protect.

Some early conservation strategies may seem strange by modern standards, and have had unintended negative consequences. For example, extreme flood control measures along the Mississippi river system exposed a large human population to catastrophic mega-floods. However early environmental policies were based on the science of the time, and were unquestionably fairer and less destructive than the unchecked industrial development they replaced.

Water conservation programs and projects played a major role in President Franklin D. Roosevelt’s (1882–1945) “New Deal” plan to revive the United States economy during and after the Great Depression of the 1930s. Government-sponsored hydroelectric projects such as the Tennessee Valley Authority (TVA), which dammed the Tennessee River for flood control and electricity generation, provided work for thousands of unemployed engineers and laborers.

The Bureau of Reclamation, a government agency that manages the surface water west of the Rocky Mountains, constructed more than 600 dams during 1920s and 1930s, including Hoover Dam on the Colorado River, and Grand Coulee Dam on the Columbia River.

East of the Rockies, the Army Corps of Engineers helped put the American public back to work by building dams and other water control structures in the Mississippi River system. The Soil Conservation Service was established to advise farmers in maintaining and developing their farmland.

Conservation or preservation? Pinchot and other early conservationists fundamentally disagreed with early preservationists who thought that some wilderness should be protected solely to preserve its beauty or its natural ecosystem. John Muir, an eloquent writer who worked to protect Yosemite Valley in California, led the early preservationist movement.

He bitterly opposed Pinchot’s vision of the nation’s wilderness and waterways as warehouses of useful materials. Because of its more moderate stance, Pinchot’s conservation became the more popular position and it has since guided U.S. environmental policy.

The preservationists did however, strike a chord with the American public and some of their ideas were incorporated into a mainstream conservation movement. In the 1960s, environmentalists echoed Muir’s arguments when they raised objections to conservation’s anthropocentric (human-centered) emphasis.

Late twentieth century naturalists such as Rachel Carson (1907–1964), Edward Abbey (1927–1989), Aldo Leopold (1913–1983), as well as more radical environmental groups, including Greenpeace and Earth First!, owe much of their legacy to the turn of the century preservationists.


Water conservation in the United States

Water is by far the most carefully managed natural resource in the United States today. The average American uses about 100 gallons (378.5 liters) of water each day for direct purposes such as drinking, cooking, bathing, washing clothes and dishes, watering lawns, and washing cars.

Per person water use is even greater when including indirect uses such as irrigation for a person’s food and water used to manufacture consumer products. A complex system of local, state, and national water boards and agencies manages the U.S. water supply to ensure that all 280 million Americans have access to a steady supply of fresh water.

It is only a slight exaggeration to say that every drop of river water in the United States encounters a human water control structure or system of some sort before eventually reaching the ocean or evaporating into the atmosphere.

All of the nation’s major rivers and most of its smaller rivers and streams are dammed, constricted by levees, or both to protect humans from floods, provide hydroelectric power, and hold back reservoirs (artificial lakes) that contain local water supplies. Engineers and water managers control river flows in the United States to such an extent that many floods and shortages are today an act of man as well as nature.

Water is one of the most economically valuable resources. In the bone-dry American West and Southwest, booming cities such as Phoenix, Las Vegas, and Los Angeles share scarce water supplies with large-scale agricultural regions such as California’s San Joaquin Valley.

Central California receives only a few inches (centimeters) of rain each year, but with irrigation water imported from the Sierra Mountains and the Colorado River, it has become “America’s salad bowl.” Much of the produce (lettuce, tomatoes, avocadoes) stocking the grocery store shelves in the United States comes from irrigated fields in the deserts of California and Texas.

The Colorado River is so heavily used by the states along its path (Colorado, Utah, Arizona, Nevada, and California) that it contains only a trickle of water where it crosses the Mexican border and it no longer reaches the ocean. (In fact, because the Colorado River water distribution plan was agreed upon during a relatively wet period, the river actually contains less water than was promised to its various human users.)

Water use is strictly regulated according to local, state, and national laws. With the exception of small lakes and streams on private property, bodies of surface water are public property. In most states private landowners must allow the general public to use water from rivers or lakes on their property. Furthermore, they must abide by the same water quality and withdrawal guidelines as the rest of their water district.

Unlike surface water groundwater usually belongs legally to the owner of the overlying land. Most groundwater laws were written before scientists understood groundwater moves in underground reservoirs, and that single users can overuse or pollute shared groundwater resources. Individuals, industries, and communities that abuse groundwater usually face few legal consequences, especially compared to users who pollute or overuse surface water.

If for example, a city’s water reservoir runs low during a dry spell the regional water district can legally purchase water from other sources, and can require the whole community to take water-saving measures like restricting summertime lawn irrigation and car washing.

If on the other hand, a farm’s well goes dry after the farmer’s neighbor lowers the water table (level below which rocks and soils are saturated with water) by over pumping, no legal action could be taken against the neighbor and the farmers would likely need to drill a deeper well.

International water conservation

Although water shortages, floods, pollution, and water-related legal conflicts are relatively common in the United States, water conservation policies generally ensure that Americans can trust their water supply. People in other parts of the world are not so fortunate, particularly in the developing nations of Africa, South America, and Asia. In many regions arid climate, rapid population growth, poverty, and political instability are a recipe for water shortages and pollution.

Two-thirds of the world’s population lives on less than 13 gallons (49 liters) of water per day. (Remember that an average American uses about eight times that much water.) When political tension becomes war or an already dry climate gets drier, people who were surviving with limited freshwater are faced with famine (food shortages leading to starvation) and disease.

In recent decades conservation has become a critical issue for the international community. Organizations such as the Unite Nations Environment Program (UNEP), the International Union for the Conservation of Nature and Natural Resources (IUCN), and the World Wildlife Fund (WWF) are working to help individual countries plan for the maintenance and protection of their resources.

Their strategy, called sustainable development, is based on a philosophy that is very similar to Pinchot’s original conservation ideal. Earlier international programs viewed environmental protection and economic development as an “either-or” decision between preserving nature and human prosperity.

Sustainable development schemes aim to address humans’ most pressing social issues like poverty, famine, and disease by solving environmental problems such as water scarcity and pollution. New strategies for coping with environmental issues also involve providing economic incentives that encourage economically powerful nations and industries to act for the common good.

Water Pollution

Water Pollution

Pollution is defined as the addition of harmful substances into the ecosystem (the network of interactions between living organisms and their environment). Pollutants might be slightly harmful to humans, but very harmful to aquatic life.

For instance, in certain lakes and rivers when acid rain (rain polluted with acidic chemicals) falls upon them, toxic (poisonous) metals that cause fish to die are released from sediments (particles of soil, sand, and minerals, and animal or plant matter washed from land into water). These metals—chromium, aluminum, and mercury are just a few—are harmful to fish.

But humans would have to ingest much larger quantities than the aquatic or marine life. The toxins also accumulate in the tissues of fish as they eat other fish (ingest) or plants containing toxins. If one were to catch and eat a fish that has a high content of toxins in them the human is affected too.