abc 3D Atlas

Rivers
Rivers are some of the oldest features on Earth, and stretch back in time millions of years. In the flowing waters of rivers, many species of plants, fish, and insects evolved during this time creating a specific “river world.”
We humans have been on earth for more than a million years, but civilization, life in cities, has come about only in the last five thousand years. Civilization was born on the banks of two rivers, the Tigris and Euphrates. Here the Sumerians built Uruk, the first city, the mother of cities. Rivers were considered the source of life itself. Rivers were sacred in all developing cultures. The civilization of Egypt, which arose on earth some five thousand years ago, drew its life from the Nile. “The Nile,” said the great Arab traveler, Ebn Battuta, “surpasses all the rivers of the world in sweetness of taste, in length of course, and utility.” Indian cities developed on the rich alluvial soil left by the annual flooding of the Indus River. The Chinese civilization arose on the banks of the Huanghe, the Yellow River, which brings its rich yellow silt down from Mongolia. Rivers provided, and still do, food, drinking water, and were the first communication highways.
Today, we are in danger of losing our rivers, lakes, forests, oceans, cities, polar ice caps, and even the protection of the ozone layer due to pollution, contamination, and the indiscriminate use of our planet. Due to human activities, many species of animals and plants are becoming extinct daily. Western civilization has been immensely successful but it has also brought a revolution of “values” that, in the words of the British historian Michael Woods, may yet be our undoing.
Most of the world’s streams and rivers are polluted as a result of human needs for water, energy, food, recreation, transportation, and manufacturing. Everything we do affects our waters, and by allowing poison in our rivers, we are slowly drinking it ourselves. World wide, 25 million people die from drinking contaminated water each year

The River and its Watershed
All rivers begin as streams. Streams form from rainfall, melting of snow or glaciers, as an outlet of a lake, and spring waters (underground water coming to the surface). Streams gradually increase in flow, join other streams establishing a branching, a tributary network, and contribute to the formation of a river. The land area that drains rain and snow melt to a river is called a watershed. Every person on earth lives within a watershed.

The Hudson River
The Hudson River, a major American waterway, is located in New York State. It flows for 510 km (315 mi), from its source in the Adirondack Mountains, past Troy, where it is joined by the MOHAWK RIVER, its main tributary, between the Catskill and Taconic mountains, and empties into New York Bay and the Atlantic Ocean at New York City. The river drains an area of 34,630 sq km (13,370 sq mi). An important transportation artery, the Hudson is navigable for oceangoing vessels to Albany and for smaller vessels to Troy. The New York State Barge Canal links the Hudson with the Great Lakes.
The Hudson is famous for its scenic beauty, which inspired the 19th-century Hudson River school of painting. The PALISADES, high cliffs overlooking the southern part of the river along the west bank, reach about 165 m (550 ft). Hyde Park, the home of President Franklin Roosevelt; Poughkeepsie; Newburgh; and West Point, the site of the United States Military Academy, are also located along the Hudson.
In 1524, Giovanni da Verrazano was the first European to sight the Hudson. Henry Hudson explored it in 1609, and the river valley was settled under the auspices of the Dutch West India Company, which established the patroon system of landholding.
Bibliography: Beecher, R., Under Three Flags: A Hudson River History (1991); Boyle, Robert H., The Hudson River (1969; repr. 1978); Carmer, Carl L., The Hudson River (1939; repr. 1974); Dunwell, F., The Hudson River Highlands (1991); O'Brien, Raymond J., American Sublime (1981); Simpson, Jeffrey, An American Treasure: The Hudson River Valley (1987) and The Hudson River, 1850-1918: A Photographic Portrait (1981).
Copyright 1995 by Grolier Electronic Publishing, Inc.

Patrick and Moris at the 79th Street Boat Basin testing site in Manhattan

 

Once every two weeks, a group of seventh grade students visits the Boat Basin on the Hudson River, at the 79th Street Marina. Here, students record air and water temperatures, take pH readings, determine the water clarity and dissolved oxygen levels, and prepare a sample for the five day biochemical oxygen demand test. is tested using a Coli-count sampler. A water sample is brought back to school to determine levels of nitrates, phosphates, coliform bacteria, and salinity.

In their work, students follow an Internal Manual compiled from different sources: the Earth Force literature which comes with LaMotte's Low Cost Estuary & Marine Monitoring Kit , various electronic encyclopedia, and from the Field Manual for Water Quality Monitoring. The Internal Manual was written in part by students and contains a general section on the world's rivers, their history, the watershed, and some information on the utility and history of the Hudson River. The test procedures conform to the procedures outlined in LaMotte's Low Cost Estuary & Marine Monitoring Kit.

Following is a brief description of the importance of the nine tests. For more detailed descriptions

1. Dissolved Oxygen

Dissolved oxygen is a measure of the health of a body of water. The absence of oxygen indicates severe water pollution. Dissolved Oxygen (DO) is important to the health of aquatic ecosystems. All aquatic animals need oxygen to survive. Natural waters with consistently high dissolved oxygen levels are most likely healthy and stable environments, and are capable of supporting a diversity of aquatic organisms. Natural and human-induced changes to the aquatic environment can affect the availability of dissolved oxygen.

Testing for Dissolved Oxygen

2. Coliform Bacteria

Fecal coliform levels are monitored, because of the correlation between fecal coliform and pathogenic bacteria, and viruses that cause diseases. Fecal coliform bacteria are naturally present in the human digestive tract but are rare or absent in unpolluted waters. Coliform bacteria should not be found in well water or other sources of drinking water. Their presence in water serves as a reliable indication of sewage or fecal contamination.

Coliform at 24 hours	A positive test result for Coliform at 48 hours

3. pH

Most natural waters have a pH value from 5.0 to 8.5. Higher or lower levels are unsuitable for most organisms. pH is a measurement of the acidic or basic quality of water. The pH scale ranges from a value of 0 (very acidic) to 14 (very basic), with 7 being neutral. Most aquatic organisms are adapted to a specific pH level and may die if the pH of the water changes even slightly.
pH can be affected by industrial waste, agricultural runoff, or drainage from improperly run mining operations.

 

Substances exhibit pH levels going from 0, for very strong acids like HCl (hydrochloric acid), to 14, very strong bases, like NaOH (sodium hydroxide). Pure water contains equal numbers of H⁺ ions and OH^- ions, and it is considered, therefore, neutral. The pH of pure, deionized water is 7.

4. Biochemical Oxygen Demand [ 5 day test ]

Biochemical oxygen demand is a measure of the quantity of the oxygen that disappears from the water due to the decomposition of organic matter. In slow moving and polluted rivers, much of the available dissolved oxygen is consumed by bacteria, robbing other aquatic organisms of the dissolved oxygen needed to live. Some possible sources of organic pollutants are:

• meat-packing plants
  
• food processing industries
  
• fecal materials from animals feed lots
  
• waste water treatment plants
  
• urban runoff from streets and sidewalks
  

Some organisms will not survive in low oxygen waters. Others like carp, and sewage worms will prosper.

5. Temperature

Thermal pollution from industries, urban runoffs, soil erosion and deforestation affect the amount of dissolved oxygen and rate of photosynthesis. Temperature affects the amount of dissolved oxygen in the water, the rate of photosynthesis by aquatic plants, and the sensitivity of organisms to toxic wastes, parasites and disease. Among the sources of thermal pollution, the warming of waters due to human activities, are industries that use river water to cool machinery and discharge warm water, and storm waters running off warm urban streets, and parking lots. Cutting down trees has several adverse effects on a watershed:

• it eliminates shady areas, adding warmer runoffs to the river
  
• it induces soil erosion which increases the amount of suspended solids in the river's water. Turbid, cloudy water absorbs the sun's rays, causing water temperature to rise.
  

6. Turbidity

Increased amounts of suspended solids reduce the transmission of light and cause waters to become warmer, with a consequent drop in oxygen levels. Turbid water may be the result of soil erosion, urban runoff, algal blooms and bottom sediment disturbances which can be caused by boat traffic and abundant bottom feeders.

7. Salinity

Salinity is the total of all salts dissolved in water. The salt content of water affects the distribution of plant and animal life in an aquatic system, based on the amount of salt they can tolerate. Variable salinity is the most characteristic feature of estuaries. Salinity at one place changes daily with the tides and tidal excursions. Salinity also changes dramatically during the seasons. The head of an estuary may experience almost full-strength seawater in the summer, while in the winter floods of fresh water may reach the mouth of an estuary. Salinity can also increase during major storms and hurricanes. In many cases, major storms can affect salinity levels for years.

8. Phosphate

The amount of phosphate found in healthy water is generally small, not more than 0.1 ppm. Larger amounts of phosphates usually wipe out the river's fish population. Phosphate is a nutrient needed for plant and animal growth and is also a fundamental element in metabolic reactions. High levels of this nutrient can lead to overgrowth of plants, increased bacterial activity, and decreased dissolved oxygen levels. Larger amounts of phosphates in polluted waters cause extensive algal growth, called "blooms." When algae cells die, oxygen is used in the decomposition process and the fish population is usually wiped out. Some of the sources of phosphate pollution are:

• sewage from waste water treatment plants
  
• animal and industrial wastes
  
• fertilizers from agricultural runoff
  
• soil erosion
  

9. Nitrate

The presence of excessive amounts of nitrogen promotes plant growth and decay, which in turn increases biochemical oxygen demand. Nitrate is a nutrient needed by all aquatic plants and animals to build protein. The decomposition of dead plants and animals and the excretions of living animals release nitrate into the aquatic system. Excess nutrients like nitrate increase plant growth and decay, promote bacterial decomposition, and therefore, decrease the amount of oxygen available in the water.
Sewage is the main source of excess nitrate added to natural waters, while fertilizer and agricultural runoff also contribute to high levels of nitrate.