A watershed is an area of land that drains runoff, sediment, pollutants, and other dissolved materials to a common outlet. Water drains from higher areas to lower areas, generally concentrating into a wetland, stream, river, or lake. All geographical locations on Earth are part of a watershed.
A watershed may cross political, land-use, and ownership boundaries. They can be made up of farmland, housing developments, industrial sites and urban areas. Buildings, people, plants and animals all have an influence in our watersheds.
The Wabash River watershed
The Wabash River, which runs through Tippecanoe County, is the second largest tributary to the Ohio River and is the longest segment of free flowing river east of the Mississippi River. The watershed has a total drainage of approximately 33,000 square miles and in 2010 had a population of around 4,366,000 people. Historically, the Wabash River served as a significant transportation corridor and helped facilitate the European settlement of the Midwest. Today, the Wabash River and its tributaries are no longer utilized for commercial navigation, but remains a vital water source in the region. The Wabash River serves as an important migration corridor for waterfowl and shorebirds, and is home to nearly 400 rare species including approximately 151 fish species and 75 mussel species. In fact, the Wabash River contains 5 of the 40 richest river segments in the United States in terms of biodiversity.
The Wabash River also faces an array of challenges—flooding, drought, water quality, and ecosystem integrity. These challenges must be addressed in a systems context that reflects the interdependence of water uses and competing interests of a diverse group of stakeholders. Moreover, there is broad interest in flood risk management, as well as the continued rehabilitation and reservation of the Wabash River. Numerous positive actions have been implemented by stakeholders in the watershed, and many others are planned. Water quantity is an important issue too; having either too much or too little water can threaten farming, residential infrastructure, and stream health. Since everyone uses water, all are affected by its supply, accessibility, and cost.
How are watersheds impacted?
Everyday activities can generate pollutants in a watershed. Some common sources are; lawns, gardens, construction sites, roadways, septic systems, and farmland. Road salt, pesticides, fertilizer, wastewater, and organic matter can be carried by stormwater runoff from throughout the watershed and get deposited in the river.
These pollutants affect the biological balance of a watershed, causing increases in algae, weed growth, and cloudy water. When such an imbalance occurs, the water quality is impacted, negatively affecting local plants, animals, and recreational activities.
Changes in land management also impact the quality of water throughout the watershed. When more homes and roads are built, stormwater runoff is intensified. Without natural protective barriers—like woodlands, prairies, and open spaces—water enters ditches, streams, and ponds at a much faster rate. The result is often a higher and more rapid flow during storm events, which can trigger the erosion of stream banks. These changes are detrimental to fish and plant life, especially in drier seasons.