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San Diego County Watersheds
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Water Quality Monitoring Constituents
Below is a list of water quality indicators. Some of these are not monitored presently by Coastkeeper, but the ones we do monitor are links that will lead you to more complete information.
Alkalinity
This indicator is a measure of the river's ability to neutralize acid inputs from precipitation or discharges. Rivers with low alkalinity are subject to great fluctuations in pH that disrupt aquatic life.
Bacteria
Certain types of bacteria are indicators of the presence of human sewage, pet waste or livestock manure and are a risk to human health. The bacteria indicator for fresh water is Escheria coli (E. coli) or fecal coliform. Enterococcus indicates pathogens in salt water and is the type of bacteria that is measured to indicate whether a beach should be closed or not. Bacteria is measured in counting the Most Probable Number (MPN).
Conductivity
Water contains various natural and human-introduced materials that are inorganic and have the ability to pass an electric current. Conductivity measures the ability of the particles in the water to transfer electricity. It is used as an indicator of the presence of chlorides, nitrates, sulfates and phosphate anions (negatively charged ions) and sodium, magnesium, calcium, iron and aluminum cations (positively charged ions). If a conductivity level is high, it indicates a potential problem from these materials. Conductivity readings are also high where there is tidal intrusion or influence, which is often the case at lagoon and estuary sites. We monitor furing low tide at these sites to minimize the influence of seawater on our samples.
Dissolved Oxygen (DO)
Water contains oxygen in the form of dissolved gas. In order to breathe, aquatic organisms - both plants and animals - access the dissolved oxygen in the water. All organisms have an optimal range of DO, and some require very high levels to flourish. Low DO levels can indicate pollution.
pH
The acidity of water is measured on a scale of 0 to 14 pH units. pH is measured using a logarithmic scale. Acidity determines the rate of many biochemical reactions in the water, and aquatic organisms have an optimal pH for functioning.
Nitrates
Nitrogen is an essential nutrient for plant and animal life. Nitrate is the form of nitrogen that is regularly available for use by aquatic plants. In saltwater streams, nitrate is usually the nutrient in shortest supply (limiting nutrient), causing a large impact on aquatic plant growth when added. It can be an indicator of fertilizer run-off, sewage, animal manure, and other types of contamination. Under certain circumstances, nitrates are toxic to aquatic life and nutrients.
Phosphates
Phosphorous is an essential plant and animal nutrient that can cause rapid increases in biological activity when levels are excessively high. Excessive plant growth due to high phopshorous levels may disrupt the ecological integrity of a stream. Phosphate is the form of phosphorous that is readily available for use by aquatic plants. In freshwater streams, relatively small amounts of phosphate can have a significant impact because it is often the limiting nutrient in the system. It can be an indicator of fertilizer, sewage, animal manure, amongst others.
Physical River Characteristics
The physical condition of the stream or river and the surrounding land is linked to the quality of stream habitat and water quality. Physical conditions that are observed and measured include: air & water temperature, width, depth, stream velocity, odor, appearance / color, surrounding land uses, stream bank vegetation, river bottom composition and overhead canopy.
Temperature
This is the basline indicator that determines the rate of many biochemical reactions in the waterbody and responds to certain types of land and water use.
Trash
Debris on streets ends up in local creeks, streams and rivers and eventually ends up on beaches and in the ocean. Trash is most closely linked with bacteria, and has a negative impact on habitat, stream ecology and recreation.
Turbidity
This is a physical indicator of water clarity, measured by the extent to which light penetrates the water column and reaches the bottom. Light is essential for plant growth, and is closely linked to water temperature. In our region, high turbidity is often a result of suspended materials in the water resulting from construction activity, power washing, or urban run-off.
The Water Quality Regulatory System
Beneficial Uses
Beneficial Uses in your Watershed
To learn more about the beneficial uses in your watershed:
1.) Locate your hyrdologic sub-area on the map linked here (warning: the map is 6.5MB, and can be difficult to read) to obtain your hyrdrologic unit number (i.e. 910.20 for Poggi Creek in the Otay River Watershed.)
2.) Identify your hydrologic unit on Table 2.2 Beneficial Uses of Inland Surface Waters in Chapter 2 of the San Diego Region Basin Plan.
Definitions
Municipal and Domestic Water Supply includes uses of water for community, military, or individual water supply systems including, but not limited to, drinking water supply.
Example:
San Vicente Reservoir is designated for Municipal and Domestic Supply. The water from the reservoir is used as the potable water supply for communities within San Diego County. Tributaries to the San Vicente Reservoir, such as San Vicente Creek, are also designated for Municipal and Domestic Supply.
August Watershed Captain's Meeting Presentation on Beneficial Uses
Watershed Data and Information
San Juan Hydrologic Unit
Santa Margarita River Watershed
San Luis Rey Watershed
Carlsbad Hydrologic Unit
San Dieguito River Watershed
Los Penasquitos Unit
San Diego Hydrologic Unit
Pueblo River Watershed
Sweetwater River Watershed
Otay River Watershed
Tijuana River Watershed
Quality Assurance / Quality Control Documentation
- Field Screening Manual, instrumentation details & datasheets
- Quality Assurance Project Plan
- Lab Protocols and Procedures
- Technical Advisory Panel
Water Monitoring Resources
- Clean Water Act
- Information on Databases
- Links and Resources
- Enforcement Hotlines
- Instructions for identifying and reporting violations
