Water quality is a term used to describe the chemical, physical, and biological characteristics of water with respect to its suitability for a particular use. Water quality standards have been developed through nearly a century of trial and error and advances in technology. Currently, both state and federal standards regulate the quality of water that is provided to users. The importance of water quality as it relates to human activity is directly related to the intended use(s) of the water. The highest quality standards apply to drinking water, while somewhat lower standards apply to water used for irrigation or recreation. The California Department of Health Services' (DHS) drinking water standards provide one example of how water quality can be evaluated (see Local Water Quality below). Water quality is also measured in ecological terms, as poor water quality affects the quality of our environment. For more information on water quality issues, click on the links below.
Local Water Quality
Water quality varies from source to source and is influenced by natural and human factors. Natural influences include the layers of rock and soil surrounding an aquifer or surface conveyance, which determine the types and amount of minerals found in surface water or groundwater. Human impacts on water quality result from such activities as urbanization (stormwater runoff and septic tanks), agricultural irrigation (runoff from irrigated land), direct disposal of wastewater into waterways, and grazing of livestock.
California DHS has set Maximum Contaminant Levels (MCLs), which are enforceable, regulatory levels under the Safe Drinking Water Act that must be met by all public drinking water systems to which they apply. Primary MCLs are established for a number of chemical and radioactive contaminants, while Secondary MCLs are set for taste, odor, or appearance of drinking water. Action Levels (ALs) are health-based advisory levels established by DHS for chemicals for which primary MCLs have not been adopted. They are not enforceable standards, but exceedances do prompt requirements for local government notification, recommendations for consumer notice and, at higher levels, recommendations for source removal. In addition, there are a number of unregulated chemicals that are or may be required to be monitored, depending on the vulnerability of drinking water sources.
The origin of water pollution is generally characterized as either being from nonpoint (diffuse) or point sources. Nonpoint source pollution is caused by rainfall or snowmelt moving over and through the ground picking up and carrying natural and human-made pollutants, and depositing them into lakes, rivers, coastal waters, and underground sources of drinking water. Point source pollution comes from sources that are concentrated and readily identifiable like discharges from wastewater treatment facilities, solid waste landfills, golf courses, stockyards, poultry farms, and feedlots. Point sources of pollution are more easily controlled and monitored so they have been the focus of most pollution reduction efforts to date. Only recently has the control of nonpoint sources become a focal point for pollution reduction efforts.
Water quality comparisons typically focus on Total Dissolved Solids (TDS), chloride, and nitrates. Chloride contamination is a concern in Santa Barbara County due to a variety of factors. The most prevalent potential source of chloride contamination in the county is from seawater intrusion. Elevated chloride levels associated with seawater intrusion occur when there are no geological barriers (impermeable bedrock or clay layers) between coastal groundwater basins and the basins under the ocean that are saturated with seawater. The likelihood of seawater intrusion is increased when extensive pumping of groundwater basins adjacent to the ocean affects groundwater flow gradients and seawater is drawn inland. Irrigated agriculture also increases chloride levels in groundwater by introducing problems of poor drainage and increasing evaporation.
Nitrates can accumulate in watersheds due to the use of fertilizers or the presence of poorly maintained septic systems. Nitrogen not taken up by plants can leach through the soil to groundwater and then flow to recharge areas or private wells. Nitrates are of particular concern in drinking water sources because nitrates interfere with the absorption of oxygen into the bloodstream. Although Santa Barbara County has extensive agricultural areas and many residents use septic systems, nitrate contamination of groundwater supplies is rare.
High levels of total dissolved solids frequently impair the use of groundwater in California. In Santa Barbara County, several groundwater basins show degradation of water quality due to high TDS levels. Total dissolved solids may be increased through natural dissolution of soluble materials, reduction in recharge from surface waters, and constant cycling and evaporation of irrigation water.
A watershed is a gathering place for water. It is an area of land from which all runoff flows and gathers to form creeks, rivers, and eventually makes its way to a larger body of water. The topography of the land dictates the places where water will gather, into the valleys and areas with low altitude. These areas gather the rainwater or runoff, which has come from higher locations. This water still travels due to gravity, until it reaches an area that is level, such as the ocean, or a lake. The Santa Ynez Mountains are the main feature of our local watersheds. Water falling on the south side of the mountains drains to the Pacific Ocean (recharging ground water along the way). Water falling on the north side drains into the Santa Ynez River, becoming part of our local surface water supply and eventually reaching the Pacific Ocean at Lompoc.
It is important to understand that we all live in a watershed and that everything we do has an impact. Examples of pollutants in watersheds include dog waste, oil, pesticides, soap, etc. Being aware of our local watersheds and our place within them is the beginning of a larger awareness and care for our natural surroundings. To find your local watershed, click on the links below.
Carpinteria & Summerland Schools
Santa Barbara Schools
Project Clean Water
EPA Drinking Water for Kids
Give Water a Hand Activity Guide
Ranger Rick's Kid Zone
Adopt Your Watershed
Locate Your Watershed