There are more than 2,300 miles of rivers and streams in the Great Miami River Watershed. The water quality in these rivers and streams has improved a lot over the last 20 years. However, there is still improvement to be made before we can say that the rivers and streams in the Great Miami River Watershed are "unimpaired" by pollution.
Historically, the cause of most water pollution came from point sources, or discharges, from a specific location such as a pipe or disposal site (usually factories and industry).
Since the Federal Water Pollution Control Act passed in 1972 (Clean Water Act), much progress has been made in preventing water quality problems from the point sources.
Presently, in our watershed, most water quality problems come from destruction of natural aquatic habitat or polluted runoff, also called nonpoint source pollution. These sources are often hard to identify and difficult to measure, but are often the result of little things we do around the house.
Nonpoint Source Pollution
Nonpoint source pollution is caused when pollutants are carried over and through the ground by rainfall or snowmelt. As the runoff moves, it picks up and carries away natural and human-made pollutants, depositing them into lakes, rivers, wetlands, coastal waters and even our underground sources of drinking water. The major sources of nonpoint pollution include:
- Excess fertilizers, herbicides and insecticides from agricultural lands and residential areas.
- Hydromodification—straightening or moving streams, dredging and building low dams.
- Oil, grease and toxic chemicals from urban runoff and energy production.
- Sediment from improperly managed construction sites, crop and forest lands, and eroding streambanks.
- Salt from irrigation practices and acid drainage from abandoned mines.
- Bacteria and nutrients from livestock, pet wastes and faulty septic systems.
- Deposits of air pollutants, such as mercury.
