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
To view these profile
sheets, you need the Adobe Acrobat Reader. Don't have it?
Download it for free here:
|
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
|
Coastal/Estuarine |
- 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.
- The
Impervious Cover Model - As the percentage of impervious cover
increases in a subwatershed, stream quality tends to diminish. This simple
classification system allows a community to predict current and future stream
quality based on the assessment of impervious cover.
- The
Simple Method - This model allows stormwater runoff pollutant
loads to be calculated with a minimum need for data collection. The Simple
Method estimates pollutant loads for chemical constituents as a product
of annual runoff and pollutant concentrations.
- Rapid
Stream Assessment Technique (RSAT) - The Rapid Stream Assessment
Technique was developed by John Galli at the Metropolitan Washington Council
of Governments. This assessment methods allows an investigator to rapidly
assess stream conditions and identify stream restoration needs. The information
is provided in a downloadable PDF format.
- Rapid Bioassessment
Protocols (RBP) - The Rapid Bioassessment Protocols are a series
of methodologies developed by the U.S. Environmental Protection Agency for
assessing water quality, habitat, and biology in streams and rivers. Click
on the link below to go to EPA's Rapid Bioassessment web page:
http://www.epa.gov/owow/monitoring/rbp/
- Stream Visual
Assessment Protocol (SVAP) - The USDA Natural Resource Conservation
Service (NRCS) developed the Stream Visual Assessment Protocol as a basic
assessment technique that does not require extensive biological expertise
or training. This assessment is intended to be conducted in cooperation
with landowners as an educational/outreach tool. Click on the link below
to go to the USDA NRCS water quality assessment web page:
http://www.wcc.nrcs.usda.gov/water/quality/frame/wqam/
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.