An Introduction to Stream Monitoring

Surface Water is monitored for several reasons:

To identify trends and changes in water quality over time
to identify existing or emerging water quality problems
To assist in the design of pollution prevention or remediation programs
To determine whether project goals are being met or projects are effective
To determine the impacts of a discharge or land-use practice
To respond to emergencies such as floods or toxic spills

Measures things like temperature, dissolved oxygen and pH
This kind of monitoring gives a “snapshot in time” of the health of the surface water
Chemical monitoring can be done using field kits, or by sending samples to a reliable lab; however, obtaining accurate results can be expensive using either method
There are standard operating procedures and QA/QC procedures than must be strictly adhered to
Monitoring is done by most volunteer groups on a monthly basis

This kind of monitoring illustrates the health of the water body over time
Most sampling is done quarterly and focuses on sampling macroinvertebrates, although fish or algae/plant monitoring is also done
This type of sampling is relatively cheap, easy to learn and hand-on.
Can provide insight into the nature of stream disturbance by examining the feeding patterns of the organisms (shredders, collectors, scrapers and predators)
Can indicate past problems that chemical monitoring cannot

To learn more about the method we use to calculate a water quality index number for a stream, visit the Virginia Save Our Streams Stream Study web page. The page also includes a link to a useful guide to aquatic marcroinvertebrates.

Visual Assessment/Watershed Surveys

This type of monitoring involves a comprehensive survey of the geography, land and water use, actual and potential pollution sources and a stream history component
Visual Assessment is a relatively cheap type of monitoring and can give citizens an idea about possible sources of pollution.

For a detailed instructions on the methods recommended by the Department of Environmental Quality for citizen stream monitors, including chemical and biological testing, as well as visual stream assessment, download DEQ's Virginia Citizens Monitors Methods Manual (486.6 KB).

Types of Water Impairments

Toxic

E.g. lead, mercury, oil or grease from industrial, agricultural or domestic sources
Not the biggest form of pollution, but difficult and expensive to remedy

Sediment

Fast moving water (from channel alterations and impervious surfaces) can erode channel banks and increase sediment in surface runoff
Agricultural or forestry practices can also leave ground exposed and result in increased sediment entering the stream during rains
Destroys aquatic habitat by smothering benthic life, clogging fish gills, increasing water temperature and blocking sunlight

Nutrient

Caused by excess nitrogen and phosphorus from agricultural runoff, detergents, fertilized lawns, sewage plants and livestock operations
Increases algae growth, which blocks sunlight, kills plants and decreases oxygen

Pathogenic

Bacteria, viruses and protozoa, fecal in origin, that come from wildlife, livestock operations or faulty septic systems

Parameter Definitions

Dissolved Oxygen (DO)

Oxygen is introduced into the stream system by plants and from the atmosphere
Running water can dissolve more oxygen than still water
DO fluctuates seasonally as well as over a 24 hour period
The amount of DO varies with water temperature and with altitude
The amount of DO helps to determine which macroinvertebrates can survive in that stream

pH is a measure of the alkalinity or acidity
pH ranges from one to fourteen based on powers of ten
A pH lower than 7 indicates acidic conditions while a pH greater than 7 indicates alkaline conditions
Changes in pH can activate toxic chemicals in the water and hinder reproduction in certain organisms

Total Suspended Solids

Turbidity is a measure of how clear the water is and how much the suspended solids hinder the passage of light
Clay, silt, sand, algae, plankton, microbes and other substances can increase turbidity
High amounts of suspended particles can clog fish gills and affect the development of eggs and larvae
High levels of turbidity can increase the water temperature

Fecal Coliform Bacteria

Measures of fecal coliform are used to indicate possible sewage contamination as fecal coliforms are found in animal and human feces.
Fecal coliform bacteria are not harmful themselves, but they indicate the possible presence of disease-causing bacteria, viruses and protozoan that live in digestive tracts.
They can also cause unpleasant odors, cloudy water and increase oxygen demand.

Temperature

Most aquatic organisms operate within an optimum range of temperature
Higher than normal temperature tend to cause greater damage to aquatic organisms when compared to cooler than normal temperatures
Temperature changes also affect dissolved oxygen, photosynthesis and the sensitivity of some organisms to toxins, parasites or disease

Total Nitrogen

Nitrogen is an essential nutrient for animal and plant development; however too much nitrogen accelerates plant growth and algal blooms
When algal blooms occur, the increased number of decomposing bacteria uses up much of the dissolved oxygen. This impacts the entire aquatic system.

Total Phosphorus

Phosphorus is an essential nutrient for animal and plant development; however too much phosphorus accelerates plant growth and algal blooms
When algal blooms occur, the increased number of decomposing bacteria uses up much of the dissolved oxygen. This impacts the entire aquatic system.

Other Useful Definitions

Watershed

The area of land from which runoff drains to a stream, river, or other body of water such as a lake or ocean.
A watershed can be less than an acre of land draining to a small local stream, or as large as the Mississippi watershed, which drains land in 30 states and 2 Canadian provinces.

Point Source Pollution

Pollution with a clearly identifiable source
Examples are pipes from factories or wastewater treatment plants.

Non-Point Source Pollution

Caused by surface runoff.
Difficult to pinpoint because such a large area of land is involved.
Examples are runoff from parking lots, construction sites, farms, or mine drainage.