Pollution control begins with testing and monitoring of water quality. Water quality is usually monitored using easy to measure indicators such as pH, specific conductance (commonly referred to as conductivity), temperature, fecal and total coliform bacteria, dissolved oxygen, macroinvertebrates, and algae. Polluted sites typically have reduced dissolved oxygen (DO) levels, lower pH (higher acidity), higher nutrient levels, more bacteria, and higher temperatures compared to less impacted or pristine sites.
Non-point source pollution control relates mostly to land management practices in the fields of agriculture, mining, and urban design and sanitation.
Agricultural practices leading to the greatest improvement of sediment control include:
- contour grading (grading across a slope rather than up and down it)
- avoidance of bare soils in rainy and windy conditions
- polyculture farming (raising more than one crop in an area) resulting in greater vegetative cover
- increasing fallow (unplanted) periods
Minimization of fertilizer, pesticide, and herbicide runoff is best accomplished by:
- reducing the quantities of these materials
- applying fertilizers during periods of low precipitation
- avoiding the use of highly water soluble pesticides and
- using materials that decay to benign (harmless) substances most quickly
The main water pollutants associated with mines and quarries are:
- aqueous slurries of minute rock particles, which result from rainfall scouring exposed soils and also from rock
washing and grading activities
- runoff from metal mines and ore recovery plants
Control of this runoff is chiefly achieved by preventing rapid runoff and designing mining operations that avoid tailings on steep slopes or near streams.
In the case of urban pollution control, good urban planning and design can minimize stormwater runoff. Effective measures may include:
- reducing impermeable surfaces (pavement that doesn’t allow water through)
- reducing the amount of surface water runoff that carries pollutants into surface water and causes flooding
- periodic use of street sweeping to reduce the sediment, chemical and rubbish load that can enter the storm sewer system
- use of native plant and xeriscape techniques to reduce water use and water runoff and minimize the need for pesticides and nutrients
The two common approaches to water management fall under either voluntary programs or regulatory programs.
Voluntary programs, together with new amendments to regulations, have had great success in increasing conservation and reducing diffuse nonpoint-source pollution. One of the most widely used voluntary programs is Watershed Management.
The Water Management Approach recognizes that water contamination problems are complex and not localized to one section of a river. Water pollution problems are caused by multiple activities within the watershed and, therefore, require holistic approaches in the entire watershed. A focal point of water management plans is the Best Management Practices (BMPs) section. BMPs are designed to consider all of the various uses of water, maximize conservation and minimize pollution.
The regulatory approach has been very successful in controlling and reducing point-source pollution, which was the focus of regulations when they were first introduced. The regulatory approach, centered on the Clean Water Act (CWA), uses policy and laws with the goal of cleaning up polluted water, preventing further pollution, and applying punitive measures for polluters. In the US, water-related regulations go as far back as 1899 with the Rivers and Harbors Act, also known as the Refuse Act, which prohibited the dumping of solid waste and obstruction of waterways. This regulation, however, did not include waste flowing from streets and sewers.
The Cuyahoga River in Northeastern Ohio cuts through Cleveland and feeds into Lake Erie. This river was so polluted from industrial waste that it caught fire multiple times from the 1940s to 1960s. One of these fires in 1969 caused a strong public outcry that fueled the emerging environmental movement, helped prompt the first annual Earth Day exactly 10 months later on April 22, 1970, and eventually led to the passage of the Clean Water Act (CWA) of 1972.
The Clean Water Act is a primary federal law governing water pollution. This regulation includes numerous programs for water quality improvement and protection. The US Environmental Protection Agency (EPA) works with its federal, state and tribal regulatory partners to monitor and ensure compliance with clean water laws and regulations in order to protect human health and the environment.
Some important facts on the Clean Water Act:
- The ultimate goals of the Clean Water Act are to establish zero pollutant discharge and to increase the amount of fishable & swimmable waters in the country.
- The act covers both point sources and non-point sources of pollution.
- One main component of the CWA is regulations on industrial and municipal discharges into navigable US waters.
- The act is designed to be a partnership between states and the federal government, with states having the power to set standards that are more stringent than the federal standards, if needed.
- Negligent or knowing violation of the CWA can result in a prison sentence of up to three years and/or a fine of up to $50,000 per day, with penalties increasing for repeat offenders.
- Another component of the act is providing funding for constructing municipal waste water treatment plants and other projects to improve water quality (Title II and Title VI).
One other major piece of regulation governing water is the 1974 Safe Drinking Water Act (SDWA). (It was amended in 1986.)The SDWA was enacted to establish standards for many chemicals in public water supplied by public water agencies. In the regulations, maximum contaminant level goals (MCLG), which are non-enforceable, and maximum contaminant levels (MCLs) that are enforceable were created. MCLG are what would be ideal and desirable, while MCL are what should be attained in any drinking water supplied by a public municipal agency. For any carcinogen, the MCLG is 0 even though many contaminants have MCLs and detection limits in the parts per billion (ppb) range. Some of them (e.g. dioxin) have MCLs in the parts per trillion (ppt). To give you a sense of how small ppt is, it is comparable to 0.4 mm divided by the distance to the moon.
Area of land that all drains to the same body of water.