Purpose and Study Design
16
Monitoring of lake and stream water quality is performed to provide
resource managers with information on possible water quality problems that
may require intervention, to determine the susceptibility of lakes and streams
to potential stressors, and to document future changes (improvement or deterioration) in key parameters of interest or in known problem areas. For example,
resource managers may need to know surface water sensitivity to acidification when they review emissions permit applications. Information from a welldesigned and properly executed monitoring plan will allow future evaluation
of the effectiveness of emissions controls or other best management practices
(BMPs) and the potential need for other actions that might be warranted.
1.2 STUDY DESIGN
Water quality studies for evaluating aquatic effects of atmospheric deposition
are most commonly designed as lake or stream characterization studies, synoptic surveys of the chronic chemistry of lakes or streams in a particular forest
or region, characterization of episodic variations in chemistry in response to
rainstorms or snowmelt, or long-term monitoring (LTM) studies to document
and quantify changes in chemistry over time. Each type of design is described
in the following material. In selecting an appropriate design, it is most important to determine in advance precisely what it is that you would like to know.
From this will spring logically the type of study design that will be most useful
(Table 1.7).
One of the most important, and most frequently overlooked, aspects of study
design is that it should incorporate the data requirements of the statistical procedures that will be used to analyze the data. Thus, it can be helpful to consult
with a statistician, or at least a person who is knowledgeable about statistics,
as part of the process of developing the study design. In addition, it is helpful to
consider what you intend to do with the data before you design the study and
before you actually collect the data. It can also be helpful to coordinate with
existing efforts by other research groups or governmental agencies. This coordination effort may be as simple as collecting some additional data that might
be shared or pursuing joint funding for a desired sampling effort.
1.2.1 Lake or Stream Characterization
To characterize the chemistry of a lake or stream, there are multiple possible approaches for water quality characterization. Some studies are based
on only one or a few samples. Most commonly, these are collected as index
samples. Decisions will need to be made concerning the frequency and timing of sampling. Springtime base flow samples are often regarded as a good
16
Monitoring of lake and stream water quality is performed to provide
resource managers with information on possible water quality problems that
may require intervention, to determine the susceptibility of lakes and streams
to potential stressors, and to document future changes (improvement or deterioration) in key parameters of interest or in known problem areas. For example,
resource managers may need to know surface water sensitivity to acidification when they review emissions permit applications. Information from a welldesigned and properly executed monitoring plan will allow future evaluation
of the effectiveness of emissions controls or other best management practices
(BMPs) and the potential need for other actions that might be warranted.
1.2 STUDY DESIGN
Water quality studies for evaluating aquatic effects of atmospheric deposition
are most commonly designed as lake or stream characterization studies, synoptic surveys of the chronic chemistry of lakes or streams in a particular forest
or region, characterization of episodic variations in chemistry in response to
rainstorms or snowmelt, or long-term monitoring (LTM) studies to document
and quantify changes in chemistry over time. Each type of design is described
in the following material. In selecting an appropriate design, it is most important to determine in advance precisely what it is that you would like to know.
From this will spring logically the type of study design that will be most useful
(Table 1.7).
One of the most important, and most frequently overlooked, aspects of study
design is that it should incorporate the data requirements of the statistical procedures that will be used to analyze the data. Thus, it can be helpful to consult
with a statistician, or at least a person who is knowledgeable about statistics,
as part of the process of developing the study design. In addition, it is helpful to
consider what you intend to do with the data before you design the study and
before you actually collect the data. It can also be helpful to coordinate with
existing efforts by other research groups or governmental agencies. This coordination effort may be as simple as collecting some additional data that might
be shared or pursuing joint funding for a desired sampling effort.
1.2.1 Lake or Stream Characterization
To characterize the chemistry of a lake or stream, there are multiple possible approaches for water quality characterization. Some studies are based
on only one or a few samples. Most commonly, these are collected as index
samples. Decisions will need to be made concerning the frequency and timing of sampling. Springtime base flow samples are often regarded as a good