Tools for Assessing Stream Quality


Environmental Indicators

Environmental indicators are select parameters and indices which can be used to characterize overall conditions in the receiving water and provide benchmarks for assessing the success of watershed management efforts. A profile sheet is provided for each of the 26 environmental indicators that includes a brief description of the indicator; a discussion of the indicator utility; a review of indicator advantages and disadvantages; an indicator case study; implementation costs (in 1995 dollars); and references. Click on the indicators in Table 1 to view the profile sheets.

Table 1. Potential Watershed Indicators
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Water quality indicators:

Physical and hydrological indicators:

Biological indicators:

Social indicators:

Programmatic indicators:

Site indicators:

(Source: Adapted from Claytor, 1996)

The identification of appropriate indicators for monitoring programs should be based upon watershed or sub-watershed management goals and/or categories, regional and site-specific considerations, and available resources. Some examples of indicators and methods appropriate for differing watershed management categories are shown in Table 2.

Table 2. Watershed Indicators Appropriate for Different Management Categories

Subwatershed Management Category Suggested Indicators
Sensitive Stream

  • Single species biomonitoring (e.g., salmon, trout)
  • Impervious cover measurements
  • Aquatic habitat and the stream geometry
Impacted Stream
  • Impervious cover measurements
  • Aquatic habitat and stream geometry
  • Biological indicators such as macroinvertebrate and fish populations
Non-Supporting Stream
  • Single species biomonitoring
  • Selected chemical constituents such as metals, hydrocarbons, and other toxins
  • Trash and debris surveys
  • Public attitude surveys

Restorable Stream
  • Impervious cover measurements
  • Aquatic habitat and stream geometry
  • Biological indicators such as macroinvertebrate and fish populations
  • Trash and debris surveys
  • Public attitude surveys
  • Programmatic indicators
Urban Lake
  • Impervious cover measurements
  • Monitoring for selected chemical constituents, such as phosphorus
  • Water clarity or turbidity
  • Bacteria monitoring or beach closures
  • Programmatic indicators
Water Supply Reservoir
  • Impervious cover measurement
  • Monitoring for selected chemical constituents such as bacteria and other pathogens
  • Water clarity or turbidity

  • Biological indicators such as macroinvertebrate and fish populations
  • Monitoring for selected chemical constituents
  • Bacteria monitoring, shellfish beds, or beach closures

 Aquifer Protection
  • Impervious cover measurement
  • Biological indicators such as amphibians, macroinvertebrates and fish
  • Selected chemical constituents such as metals, hydrocarbons, and trace metals

Regardless of the specific indicators selected, it is important to utilize scientifically reliable assessment techniques, quality controls, and valid sampling protocols to ensure that results are repeatable, consistent, and compatible with other data collection efforts. The rapid assessment methods presented in this section incorporate these necessary elements.

This first step in utilizing environmental indicators is to establish a baseline or current condition. This baseline condition will be used as the basis by which to judge the success of future watershed management actions. This baseline condition then needs to be compared to a reference condition. The reference condition represents the best attainable condition for that indicator in a "least disturbed" location. For the reference condition to be appropriate, the reference condition must be from an area of similar natural environmental conditions, in other words, within the same geologic province, ecoregion, and of the same drainage area and/or stream order to reflect what the baseline condition would be in the absence of disturbance.

Some environmental indicators require that monitoring stations be established and field sampling conducted, while others can be derived from existing programmatic resources and records. Indicator monitoring may require several years of sampling to establish trends and assess program effectiveness. For those indicators that require field sampling, there are several key factors to consider when establishing long term field monitoring stations. Poorly sited stations may provide no useful information, or require years of additional data collection to provide the required information. Table 3 highlights some key factors to consider when locating field monitoring stations.

Table 3. Key Factors to Look at When Locating Indicator Monitoring Stations

Locational Consideration Notes
Station should be representative of subwatershed characteristics Consider available resources (funds and staff) to determine the number of stations per subwatershed. Remember that the assessment of management measures will depend on results of monitoring and subwatershed classification will depend on conditions of resource.
Stations should be located downstream of proposed future activities In order to assess the implementation of land use management techniques, BMPs or other subwatershed protection measures, monitoring stations must be carefully located in order to compare before and after conditions.
Stations should be located based on a statistical randomness criteria (where appropriate) When using the monitoring data to compare multiple subwatersheds, the location of stations should be consistent across the spectrum of subwatersheds being analyzed. Two commonly used techniques are to locate stations at the confluence of second order streams or just upstream of road crossings.
Stations should be relatively easy to access Some stations will need to be revisited tens to hundreds of times. Managers need to consider ease of access and time in locating stations.
Stations not likely to be compromised by vandals or storm damage Stations that involve installing expensive or sophisticated monitoring equipment should be located in a "secure" area and consideration should be given to what will happen to equipment during a major storm. Equipment may need to be housed in a durable monitoring "house" or have remote sensors or samplers to collect data.

Rapid Assessment Methods

Indicator monitoring often involves complex data collection and analysis techniques that can require substantial investments of time and resources. Local communities often lack the resources and expertise to undertake these complex tasks, yet need accurate information on watershed and stream conditions. This section highlights some of the rapid assessment methods that can be undertaken with a minimum resource commitment while producing timely, useable information. Click on the titles of the methods described below to learn more.

About the Monitoring/Assessment Section

Need to characterize conditions in your watershed, but don't have much time or money to do so? Check out some simple and fast methods to get a handle on pollution and stream habitat problems in your watershed.