biological potential. Problem documentation or problem identification monitor-
ing is an essential first step of a watershed management program. Specific
pollutant constituents should be documented as causing the water quality problem.
Clearly documenting specific pollutants causing the problem and monitoring for
their impact helps to avoid monitoring pollutants which are not vitally important.
Carefully documenting the problem assists project staff in clearly defining land
treatment and monitoring objectives of the project.
Table 3.1 Monitoring Objectives and Level of Detail.
General Motiitoring Objective
Evaluate Current Conditions
Trend Detection (variables)
Load Monitoring (loads)
Standards violations is an important objective; however, because a careful
examination of this topic is beyond the scope of this guide, standards violations
will not be discussed herein. For level I trend detection, a large and persistent
change in a variable with respect to background is required to evaluate program
Level II monitoring is more intensively detailed, with more comprehensive data
load monitoring is usually
collection and higher cost. Compared to level I, level II may involve a higher
sampling frequency, sampling more variables, sampling variables that are expen-
sive to analyze, or sampling at a greater number of locations. Level II trend
a trend, impact, of a
detection or load monitoring is usually best suited to demonstrate a trend, impact,
or a cause-and-effect relationship between a management action and a response
variable (Table 3.1). Load monitoring is used to measure the change in pollutant
ship between a manage-
mass loading rate.
and a re-
Monitoring trends in pollutant concentrations or in biological/habitat variables
may be the most direct route to an answer on treatment program effect on
designated use. Sensitivity may be low if there are not enough samples or
explanatory variables. Load monitoring is used to determine the pollutant mass
loading rate. Load monitoring requires more frequent samples as compared to
determining trends in concentrations or biological/habitat variables. Often auto-
matic sampling is required, which increases equipment and analysis costs.
Discharge and concentration measurements are essential for load calculations.
Load monitoring usually requires a level II monitoring effort.
monitoring may be useful to quantify the effect of land treatment at a
subwatershed or project area scale. Load monitoring may have informational