Agricultural drainage systems can result in high nitrogen levels
On many farms the landscape has been greatly modified in order to maximize farming output. Fields have been leveled and also modified to efficiently drain off excess water that may fall as precipitation or from irrigation practices. This pictures shows Sugar Creek in Indiana; it has been extensively modified for human use. As commonly found in small agricultural streams, Sugar Creek has been straightened, deepened, and had tile drains installed to assist in the rapid removal of water from agricultural lands. If excess nitrogen is found in the crop fields, the drainage water can introduce it into streams like these, which will drain into other larger rivers and might end up in the Gulf of Mexico, where excess nitrogen can lead to hypoxic conditions (lack of oxygen).
A eutrophic condition is a term describing a situation where of a water body has lost so much of its dissolved oxygen that normal aquatic life begins to die off. Eutrophic conditions form when a water body is "fed" too many nutrients, especially phosphorus and nitrogen. The excess food causes algae to grow out of control, and when the algae die off, the bacteria present use up a lot of the dissolved oxygen in the water body. Lack of oxygen can harm the lake's ecosystem, can cause fish die off, and can leave lakes looking like green pea soup, as this picture of Lake Dora in Florida shows.
Credit: Nara Souza, Florida Fish and Wildlife Commission
Urbanization and Water Quality: Suzhou Creek, Shanghai, China
The Suzhou Creek is a river in China that passes through the Shanghai city center. One of the principal outlets of Tai Lake, Suzhou Creek has a length of 125 kilometers, of which 24 kilometers are within the city's highly urbanized parts. Suzhou Creek has played an important role for being the demarkation line between political spheres of influences throughout Shanghai's history. Due to Shanghai's role as trade port, from the 1930s Suzhou Creek was an important shipping route, facilitating the transport of goods into the interior of China. Along the river banks, a multitude of warehouses and factories were built at this time, making the region close to the river a significant industrial area. Up to this point, the river had been heavily polluted by industries as well as domestic waste water, making Suzhou Creek locally known as "the smelly river", the most polluted river in Shanghai since the 1920s.
In this picture, sediment-laden water from a inflow tributary stream is entering a much clearer river, the Chattahoochee River in Atlanta, Georgia, USA. Just like all rivers, the Chattahoochee River has a main stem with tributaries coming into it at various points along its path. These tributaries contribute water to the main-stem flow. The watersheds of the tributaries may drain landscape that is very different in nature, and espeically in land use, than the basin of the main-stem river, and thus, water from tributaries can alter the water characteristics and water quality of the main river as it flows towards the oceans. As this picture shows, a tributary can contribute large amounts of sediment to a larger river.
I don't know the exact circumstances of the sediment-heavy inflow from this tributary into the Chattahoochee River here, but this could be a case of suburban construction occuring in the watershed surrounding the tributary along with occurrence of a large rainstorm. If proper sediment-trapping systems were not used, then rainfall runoff could wash large amounts of sediment into the tributary, where it eventually will flow into the main stem of the Chattahoochee River. These events could occur many miles away and affect the water quality far downstream.
Combined sewage overflow pipe spewing runoff and raw sewage during a major flood event
Here's a picture of a sanitary sewage overflow that illustrates a common problem that can happen during large storm events in urban areas. In many cities with older storm and wastewater systems, storm water and sewage pipes and drains are combined into a single system, and thus, overflows like these can release raw sewage into nearby rivers. This overflow happened in September 2009 during historic flooding in Atlanta, Georgia, USA. Sanitary sewer overflows occur when sewer pipes clog or pumping stations break down. As shown here, mixed sewage and rainfall runoff overflows from manholes and leaking pipes into nearby streams rather than backing up into homes and businesses.
If you are not familiar with the term "impervious surface," this picture of a typical landscape in suburban Atlanta, Georgia, USA, will help explain it. As cities grow and more development occurs, the natural landscape is replaced by roads, buildings, housing developments, and parking lots. The metro Atlanta region has experienced explosive growth over the last 50 years, and, along with it, large amounts of impervious surfaces have replaced the natural landscape.
Impervious surfaces can have an effect on local streams, both in water quality and streamflow and flooding characteristics. In areas that have a lot of impervious areas, more runoff water enters local streams and also enters at a faster rate, which can result in local flooding. Water-quality problems can occur from development which disturbs the natural landscape. For example, if development is occuring alongside a tributary and proper sediment controls are not taken, then after a rainstorm, sediment-laden water from a tributary can contribute large amounts of sediment into larger rivers.
Water running through mine tailings can become polluted
A USGS scientist and a volunteer sample metal-rich water from a seep draining a pile of mine tailings along Silver Creek, near Park City, Utah. Seeps such as this one can come from tailings piles that are remnants of past mining activities. Contaminants from hardrock mining can come from adits, waste rock piles, and from tailings that were stored along streams..
This photo shows hydraulic mining activity at the Malakoff Diggings in the foothills of the Sierra Nevada in the 1870s. Hydraulic mining was a variation on ground sluicing where the water delivered to the site would be shot through a nozzle at high pressure onto the face of the cliff, thereby washing away tons of boulders, gravel, dirt, and, in the hopes of the miners, ounces of gold. These "water cannons" were indeed very powerful-they could throw 185,000 cubic feet of water in an hour with a velocity of 150 feet per second (Sierra College). The environmental destruction they could do was also powerful.
Credit: USGS and the Bancroft Library, University of California.
The world's most acidic water is found in a mine in California
The most acidic waters ever measured are percolating through an underground mine at Iron Mountain, near the northern California town of Redding. Hot acid solutions, more concentrated than battery acid, are dripping from colorful mineral stalactites in the abandoned copper and zinc mine at Iron Mountain, in northern California. The pH of the drip water was -0.7. The beaker shown here holds 2 liters. Such high concentrations of acid and metals can have severe environmental effects when they enter a river system, since they may kill all aquatic life except microorganisms, for up to several miles downstream.
Here's a picture of a pine forest in Gernsbach, Germany. This area is part of the famous "Black Forest" which you have probably heard of. It is ironic that this forest was named the Black Forest, as the forest certainly looked more green centuries ago, before the advent of acid rain. But, decades of acid rain and acid fog have decimated the pine needles on these trees and revealing the black tree trunks—truly giving a more literal name to the Black Forest.
In the past few years the U.S. Geological Survey has been involved in a nationwide study of the water quality of watersheds throughout the United States. The program is called the National Water Quality Assessment Program. Sixty large drainage basins are being studied to investigate the water quality in the places where most of the U.S. population lives.
The local study in Georgia is the Apalachicola-Chattahoochee-Flint River Basin study. One part of this study was to check the fish in different parts of the basin to see if and how they were affected by local pollution and chemicals, such as pesticides.
The hydrologists had to come up with a way to collect the fish, and this picture shows them in action. They are actually shocking the water with a strong electrical charge to stun the fish into submission so they can be collected. The woman on the right has a power pack on her back and is holding the electrical wand. At the right moment, she submerges the wand in the creek, presses a button, and then... zap 'em and bag 'em.
A USGS hydrographer preparing a water-quality meter to measure field parameters (pH, temperature, dissolved oxygen, and specific conductance) of waters in the Okefenokee Swamp, Georgia, USA. The dissolved-oxygen probe is the longer one sticking out of the bottom of the measuring device.
Although water molecules contain an oxygen atom, this oxygen is not what is needed by aquatic organisms living in natural waters. A small amount of oxygen, up to about ten molecules of oxygen per million of water, is actually dissolved in water. Oxygen enters a stream mainly from the atmosphere and, in some areas, where groundwater infiltrates into streams. This dissolved oxygen is "breathed" by fish and zooplankton and is needed by them to survive.
Urban streams can have many problems with pollution
Bacteria are common single-celled organisms and are a natural component of lakes, rivers, and streams. Most of these bacteria are harmless to humans; however, certain bacteria, some of which normally inhabit the intestinal tract of warm-blooded animals, have the potential to cause sickness and disease in humans. Elevated levels of fecal-coliform bacteria in streams and rivers are a result of fecal contamination from warm-blooded animals. Dogs, cats, cows, as well as wildlife such as geese, deer, and beavers are all examples of possible sources of contamination. Bacteria from human sources may enter the water as a result of sewage spills, leaking sewer lines, or malfunctioning septic systems.
Here is a warning sign about polluted water in Peachtree Creek, near downtown Atlanta, Georgia, USA. .Many cities routinely monitor urban streams to measure the amounts of bacteria that, although harmless themselves, have similar sources (animal and human waste) as do the waterborne pathogens. The harmless bacteria therefore act as indicators of the possible presence of other bacteria that are not harmless. As this sign shows, bacteria can be a potential danger to people playing in urban streams.