In the Bear River watershed, the following are pollutants of concern:
- Sediments - Sediments include soil particles and other materials that enter the water through runoff from the land, erosion of stream banks or re-suspension of materials that have already settled in river or lake bottoms. Too much suspended sediment can cause increased cloudiness in the water, which may affect feeding by fish or just affect the aesthetic quality of the water. Excess sediments in streams eventually settle out and can smother fish eggs or the aquatic insects that fish rely on for food. Many other pollutants “hitch hike” on sediment particles, so sediment increases may also cause increased metals, pesticides, nutrients, bacteria, and more.
- Nutriends - Phosphorus and nitrogen act as fertilizers in the water, just as they do on land. High levels of nutrients in water bodies can cause excess aquatic plant growth. Too many microscopic plants in standing water turn the water green and turbid. Certain microscopic plants can cause taste and odor problems when this water is treated for culinary use. Some of these plants are even toxic to livestock, dogs and other animals drinking the water. Excessive growth of larger plants can interfere with boat propellers or other uses of the water. Once the excess aquatic plants begin to decay, this process uses oxygen that other aquatic organisms, like fish, need to survive.
- Bacteria - Fecal coliform bacteria, such as E. coli, come from human and animal waste. Coliform bacteria can enter water bodies by “hitch hiking” on sediments, from leaking septic tanks, or improperly dumping sewage waste from recreational vehicles, including boats. If levels of E. coli are elevated in surface water, it can indicate that other disease-causing bacteria, viruses, and protozoans may be present in the water making it unsafe for drinking or recreation.
- Low dissolved oxygen - Dissolved oxygen in the water is necessary for fish and other aquatic organisms to survive. Decaying organic materials (such as dead aquatic plants) use up oxygen in water and may cause fish kills from dangerously low concentrations of dissolved oxygen.
- High water temperature - Fish and aquatic insects are “cold blooded,” which means that their body is approximately the same temperature as their surroundings. Each type of fish is adapted to a range of temperatures. Fish adapted to colder water (such as many trout) may die if the water temperature gets too high.
How do pollutants enter the Bear River?
Pollution sources are divided into two categories: point and nonpoint. Typically, point source pollution is associated with industrial discharges, municipal waste water treatment facilities, and confined animal feeding operations. The effects of point source pollution can be traced to a “point” or a particular facility, and can often be measured at an outfall or pipe.
Nonpoint source pollution is a result of the cumulative effects of rainfall and snowmelt moving over and through the ground, carrying pollutants from various sources (e.g. you cannot point directly to the source). These sources include, but are not limited to, excess fertilizers and pesticides, toxic chemicals from urban runoff, sediment from improperly managed construction, agriculture, or development, salts from ineffective irrigation practices, and bacteria and nutrients from livestock, pets, or leaking septic systems.
Point source pollutants are regulated closely through the National Pollution Discharge Elimination System. These sources are required to get a permit, which determines what kinds of pollutants and how much of these pollutants may be discharged into the river or its tributaries.
Most of the pollutant sources in the Bear River watershed are nonpoint. There is no regulatory program to force a reduction in nonpoint sources. In these cases, individuals must voluntarily change their behaviors or practices to reduce their impact. These “best management practices” (BMPs) have been determined to reduce runoff from land and to reduce the amount of pollutants in the runoff. BMPs have been developed and are being used for many different types of land uses, including dairies, croplands, forestry practices, road building, urban storm water management, lawn care and much more.
Point sources of pollutants in the Bear River watershed include:
- Discharge from many dairies and animal feeding operations
- Discharge from municipal wastewater treatment plants
- Discharge from industries
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Nonpoint sources of pollutants in the Bear River watershed include:
- Animal waste on grazing lands, in pastures, in parks, or on private lawns
- Runoff from agricultural fields or fertilized lawns
- Slumping or erosion of bare stream banks
- Runoff from construction sites and road development
- Runoff from parking lots and roads
- Oil and other materials dumped down storm drains
- Exposed rock and soils during oil and gas exploration
- Erosion resulting from logging
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