inferred. Otherwise, the monitoring survey should conclude that the objective was
not met, or detection of change was overcome by extreme variability. In either
case, with a sound objective, well-formulated hypothesis, and careful design, the
monitoring survey may be expected to produce valuable information.
If it is not obvious that the management action is likely to cause an observable
change (e.g., when there are uncontrolled sources, inadequate treatment, or
variability masks the detection of treatment), a more sophisticated monitoring
design, making use of a carefully chosen set of spatial and temporal controls, may
beneededtoprovideevidenceofanimpact. Inothercases the magnitudeofchange
expected may be too small to detect. Failure to think through the design can result
in wasted data collection and inconclusive results.
Below are methods for specifying objectives for incorporation into the experimen-
tal design of the monitoring program. Analysis of existing data can provide
information on system variability which is useful for developing the design.
Reducing the MDC will increase the chances of statistical significance and
improve the power of the test.
A monitoring objective should be narrowly and clearly defined to address a
Formulating a Specific
specific problem at an appropriate level of detail. Spatial and temporal information
related to the problem is essential for implementing a successful monitoring
program. The monitoring objective specifies, where appropriate, the primary
variable(s), the degree of causality or other relationship, and the anticipated result
of the management action. Example monitoring objectives include:
n to evaluate current conditions in
Creek by analyzing ecological integrity
and suitability of the creek as a water supply;
to document the water quality problems in Highland Silver Lake by identify-
ing specific pollutant constituents, their magnitude, sources, and impacts on the
designated uses of Highland Silver Lake;
n to detect the trends in the dissolved oxygen concentrations in Hope Creek due
to the municipal treatment plant upgrade;
n to evaluate the impact of critical area manure management practices on the
n to determine the effect of implementing
on sediment and nutrient loads
entering Grand Lake from the Grand River watershed.
The discussion of monitoring objectives serves as a framework for the monitoring
program design discussed below.
Evaluation of Current
The purpose of assessing current conditions or ecological integrity is to evaluate
the overall health of the aquatic resource, to determine if the designated use is
being attained, and to evaluate the ecological potential of the resource. The
Rapid Bioassessment for Use in Streams and Rivers (Plafkin et al. 1989)
provides a method for collecting and integrating habitat, water quality, and
biosurvey data to evaluate current conditions. Habitat is an important determinant
of ecological potential and provides the basis for further ecological investigations.
Knowing current conditions helps the manager understand the potential for
remediation of the water resource. For example, in an agricultural watershed,