Geography of Southwestern PA

The French Creek flows into the Allegheny River at Franklin and heads towards Pittsburgh, a low plateau. There, the Allegheny combines with the Monongahela River to form the Ohio. The Ohio River then flows into the Mississippi, providing an early and current transportation route from Canada to the Gulf of Mexico.

An Altered Ecosystem

Western PA's waterways were not always as they are today. In fact, then the Monongahala River was the dominant river flowing north to Lake Erie and draining the southwest section of the state. This transformation over time was a result of glaciation during the Ice Age, which occurred more than 2 million years ago. As glaciers formed, eroded, and deposited sediments, new valleys were formed and fed with water, while other waterways were abandoned. Glacial erosion and deposition altered the landscape topography so much that the drainage patterns in Western Pennsylvania switched from a northerly journey into Lake Erie to a southerly path to the Ohio River Watershed.

Cultural History

Because the waterways of Western PA made trade and transportation possible, several settlers found the area to be an attractive place to colonize. Once the Industrial Revolution hit in the early 1800's, steel mills began to take over the city and ultimately the waterways. Mining for coal to fuel these massive mills led to polluted rivers through acid mine drainage. The mills also dumped their wastes into the river, raising the temperature to dangerous levels and killing aquatic life. The invention of steamboats and railroads allowed for the shipment and dispersal of steel to other industries, but at the cost of the environment. Forests were cut down to accommodate the railways and trees were used in the construction of the rail planks. With railways flanking each side of the waterways, steamboats navigating the waterways, and industries polluting the waterways, population grew, aquatic life died off, and toxic floods spread disease. Luckily, in the 1960's the public demanded that the waterways be "cleaned-up" through government programs and community-wide organizations. Rachel Carson, a Pittsburgh native, was instrumental in uncovering ecological threats in 1962 through her book, Silent Spring. Today, Pittsburgh's Three Rivers are home to many species of aquatic life and a favorite recreation spot for young and old alike.

Transport and Travel

Pittsburgh became a popular city because of its easily assessable waterways. Canals were developed beside the rivers and streams for transportation. Water, from the rivers and streams, would be regulated and used to fill the canals to hold large barges, which were pulled by oxen walking at the side of the canal. Later, the steamboat made human transportation efficient and even stylish, being able to go against the current of the waterway. With the booming success of steal production, railway systems were laid, generally beside a waterway since the oxen's tread path had already been determined. As ships, tugboats and barges became common ways to transport material and people, Pittsburgh's waterways grew to be busy and crowded, to accommodate economic growth. Pittsburgh's waterways are still crucial to its economic and industrial growth. According to the Army Corps of Engineers in a 1998 study, it is the busiest island port in the nation. Nearly 34,000 jobs depend on the water transportation system.

Threats to the "Three Rivers"

A lot has been done to clean up the damage done to waterways by the Industrial Revolution, but there are still cases of acid mine drainage from abandoned mines. Rain running through these mines makes its way into the rivers with a dangerously low pH, putting stress on the life within the river. Metal particles can also be washed into the river from abandoned coalmines, causing streams to turn yellowish-orange and sticking to the gills and eggs of fish. Also, since the rivers are located in an urban area, there are fewer trees to filter out pollutants and help control erosion, as a healthy riparian zone would. Some parts of the rivers are channeled, leading to wildlife inaccessibility and full exposure, which could raise the temperature of the river since there are no trees to provide shade. Finally, pesticides and herbicides from lawns are being washed into the rivers from heavy rains and general run-off, along with pavement macadam chemicals. The added chemicals are toxic to aquatic animals and can contaminant ground water.

Current Conservation Programs/Policies

It is good to know that measures are being taken to stop some of the threats to the local rivers, along with conservation policies, which look towards the future. In 1999, an "anti-degradation policy" was passed as part of the Federal Clean Water Act "to promote maintenance and protection of existing water quality." Other groups, such as the Allegheny County Conservation District and the Western PA Coalition for Abandoned Mine Reclamation work towards improved waterways. The Clean Water Fund generates money through violations against already passed clean water laws. Students are also taking part in waterway conservation through projects such as Creek Connections, where students study the water chemistry of their stream and assess its health, the Environthon, where students present the environmental experiments they performed, and through studies and projects in the classroom.