Jump to main content or area navigation.

Contact Us

Water: Nonpoint Source Success Stories

Glossary

Photo of marsh with mountains in background.
Acid mine drainage
Mine leachate, or drainage, that contains free acidic sulfates (usually, ferrous acid). Sulfide minerals generally break down in the presence of oxygen and water.

Animal feeding operations (AFOs)
Facilities where animals have been, are, or will be stabled or confined for a total of 45 or more days in any 12-month period and crops, vegetation, forage growth, or post-harvest residues are not sustained in the normal growing season over any portion of the lot or facility.

Aquifer
A groundwater supply that is able to release water in quantities sufficient to supply reasonable amounts to wells.

Best management practice (BMP)
A practice or combination of practices that are determined to control point and nonpoint pollutants at levels compatible with environmental quality goals.

Channelization and channel modification
Engineering activities or techniques undertaken to change stream and river channels for certain reasons, including flood control, navigation, and drainage improvement. These activities include straightening, widening, deepening, relocating, and clearing or snagging operations that generally result in more uniform channel cross sections.

Concentrated animal feeding operations (CAFOs)
Facilities that (1) confine more than 1,000 animal units or (2) confine 301 to 1,000 animal units and discharge pollutants into waters of the United States.

Constructed wetland
An engineered system designed to simulate natural wetlands to exploit the water purification functional value for human use and benefits. Constructed wetlands consist of former upland environments that have been modified to create poorly drained soils and wetland flora and fauna for the primary purpose of removing contaminants or pollutants from wastewater runoff.

Dissolved oxygen
The concentration of free molecular oxygen in the water column. Although oxygen makes up about 90 percent of water, its concentration in water is higher near the surface and declines to almost zero at the lowest depths. An absence of dissolved oxygen causes fish kills and the condition known as hypoxia, or dead water.

Effluent
Solid, liquid, or gaseous wastes that enter the environment as a by-product of human activities.

Erosion
Wearing away of the land surface by running water, glaciers, wind, and waves.

Estuary
The part of the river that is affected by tides; the region near a river's mouth in which the fresh water in the river mixes with the salt water of the sea.

Eutrophication
The alteration of lake ecology through excessive nutrient input, characterized by excessive growth of aquatic plants and algae and low levels of dissolved oxygen.

Fecal coliform bacteria
Bacteria normally found in the intestinal tracts of warm-blooded animals. These bacteria are normally harmless to humans but are used as indicators of the presence of sewage that might contain other bacteria and viruses.

Feedlots
See Animal feeding operations and Concentrated animal feeding operations.

Floodplains
Land areas adjacent to rivers and streams that are subject to recurring flooding.

Groundwater
Underground water supplies stored in aquifers; the source of groundwater is rain, which soaks into the ground and flows down until it is collected at a point where the ground is not permeable.

Habitat
The place where a biological species naturally lives or grows.

Heavy metals
Elements with a large atomic number, including copper, cadmium, lead, selenium, arsenic, mercury, and chromium. These elements accumulate in the tissues of organisms that come into contact with them (especially in aquatic settings) and are passed through the food chain. Heavy metals can be harmful or fatal in high concentrations.

Hydrocarbons
Organic compounds containing hydrogen and carbon atoms that are found in petroleum products. These compounds have adverse affects on human and animal health and might be linked to some forms of cancer.

Impaired waters
Lakes, streams, or rivers where pollutant concentrations exceed those set by the water quality standards for the waterways' designated uses.

Integrated pest management (IPM)
A pest population management system that uses cultural practices to anticipate and prevent pests from reaching damaging levels. IPM uses all suitable tactics, including natural enemies, pest-resistant plants, cultural management, and pesticides, leading to economically sound and environmentally safe agriculture.

Invasive species
A species that does not naturally inhabit an area and whose introduction is likely to cause economic or environmental harm or adversely affect human health.

Karst
A type of topography characterized by closed depressions, sinkholes, underground caverns, and solution channels.

Leachate
Liquid that has percolated through a soil and contains substances in solution or suspension.

Leaching basins
A method of capturing and treating urban runoff from roadways. These basins are designed to catch runoff water and remove pollutants such as hydrocarbons, heavy metals, and fecal coliform bacteria.

Load
The quantity of material that enters a water body over a given time interval.

No-till farming
Farming practices that reduce the need for tilling and the number of times soil is tilled each year. By reducing the frequency of tilling, soil is left undisturbed, resulting in less sediment runoff into nearby waterways.

Nonpoint source pollution
Water pollution that comes from many diffuse sources rather than from a specific point, such as an outfall pipe; often the unintended result of human activities.

Nutrients
Elements, or compounds, essential as raw materials for organism growth and development, such as carbon, nitrogen, and phosphorus.

On-site sewage treatment systems
Means of treating human or animal wastes for properties that are not connected to a central sewage treatment system. On-site systems, or septic systems, break down wastewater and disperse it into the ground to be recycled.

Organic enrichment
Amounts of organic material that exceed a waterway's capacity to maintain high levels of dissolved oxygen. Decaying organic material, such as aquatic plants or organic material in nonpoint runoff wastewater, depletes oxygen levels in a waterway and sometimes results in impairment or death in aquatic life.

Pathogens
Disease-causing agents, including viruses, microorganisms, and bacteria.

Point source pollution
Water pollution that comes from a specific, definable source.

Pollutant
Dredged spoil, solid waste, incinerator residue, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock sand, cellar dirt, and industrial, municipal, and agricultural waste discharged into water (Section 502(6) of the Clean Water Act as amended by the Water Quality Act of 1987, Public Law 100-4).

Retrofitting
The creation or modification of an urban runoff management system in a previously developed area. Such systems include wet ponds, infiltration systems, wetland plantings, streambank stabilization, and other best management practices for improving water quality and creating aquatic habitat.

Riparian areas
Vegetated ecosystems along a water body through which energy, materials, and water pass. Riparian areas characteristically have a high water table and are subject to periodic flooding and influence from the adjacent water body.

Runoff
The part of precipitation, snowmelt, or irrigation water that runs off the land into streams or other surface water. It can carry pollutants from the air and land into the receiving waters.

Section 303(d)
The section of the Clean Water Act that requires states to identify impaired waters and prepare the Total Maximum Daily Load required to ensure protection of the impaired waters.

Sediment
Solid material, both mineral and organic, that is in suspension, is being transported, or has been moved from its site of origin by air, water, gravity, or ice.

Sedimentation
The process or act of depositing sediment.

Sewage lagoon
A reservoir or pond built to contain water and animal wastes until they can be decomposed by aerobic or anaerobic action.

Storm water
Water generated by rainfall.

Surface water
All water whose surface is exposed to the atmosphere.

Suspended sediment
The very fine soil particles that remain in suspension in water for a considerable period of time.

Tailings
Rock residue from the mining process.

Total Maximum Daily Load (TMDL) Program
This program, established by Section 303(d) of the Clean Water Act, provides for the protection of waters in areas where pollution control is not stringent enough to achieve water quality standards. The program authorizes states to assess water quality and to allocate the total maximum allowable daily load(s) of pollutant discharges to those waters, regardless of the pollutant's source. Future TMDLs are expected to emphasize wet-weather storm water discharges and nonpoint source pollution problems.

Turbidity
A cloudy condition in water due to suspended sediment or organic matter.

Water quality
A term that reflects the condition of water that has been affected by natural processes and human activities; good water quality may mean that the water meets its designated uses; that is, it is fishable and swimmable.

Watershed
A drainage area or basin in which all land and water areas drain of flow toward a central collector such as a stream, river, or lake at a lower elevation.

Wetlands
Areas that are inundated or saturated by surface water or groundwater at a frequency and duration to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, and bogs.

Top of page


Jump to main content.