Chapter 2: Program Analysis
Wafer Quality Monitoring,
Lesson: The most effective experimental
design for documenting BMP impacts on
and Reporting
water quality is the paired watershed de-
(continued)
sign, in which
watersheds with similar
physical characteristics and,
land
use, are monitored for one to two years to
Lesson: Trend detection is more effective
pollutant- runoff response rela-
if monitoring focuses on
samples
tionships. Following this initial
at a relatively high frequency and analyz-
period, one watershed receives treatment
ing them for a small number of relevant
and monitoring continues in both water-
variables. Use of the entire list of variables
sheds for one to two years. This experimen-
employed to measure general conditions in
tal design accounts for many factors that
ambient monitoring programs should be
may affect response to treatment; as a
avoided. Variables measured should re-
result, the treatment effect can be more
spond directly to the implementation of
effectively isolated.
and
reflect the water quality
problem.
The Vermont project, which
a
paired watershed experimental design, demon-
project personnel indicated
strated the effectiveness of reducing nitrogen
that they could have saved money,
and
and phosphorus concentrations in field runoff by
data storage and management by reducing the
properly timing manure application
number of variables
for at some sam-
pling stations.
Lesson: Trend monitoring stations estab-
n
lished to collect
data for a
Lesson: The monitoring design should in-
after monitoring approach must remain
clude
an experimental control.
and must be downstream from sites
Controls may be either a site above an
planned for installation of
Each
installed BMP or a paired watershed in
station must remain fixed during and after
which
have not been implemented.
implementation to assure a valid compari-
son with the pre-implementation
E x a m p l e : T h e U t a h project used an up
data. Baseline data should be collected for
comparison before, during,
and after
implementation
show reduc-
a period of time sufficient to characterize
tions in phosphorus concentration below a dairy
pre-BMP
conditions.
that
a waste management system.
The Virginia
project had ac-
The Idaho
project
cess to baseline water quality data that had been
utilized the upstream/downstream strategy
collected three years prior to implementation.
monitoring before, during, and
This allowed for a thorough characterization of
ova a ten-year period to document
the
quality problem and targeting of ap-
the effectiveness of sediment reduction
propriate
Example:
monitoring
The Florida, Oregon, Idaho, Ne-
stations were located in the tributaries and on
braska, Pennsylvania, Vermont, and Utah
Long Pine Creek (Nebraska project) to docu-
RCWP projects had adequate
monitor-
ment water quality improvements from irriga-
ing with
stations below sites planned for
tion
management and
installation of BMP monitoring, which
es-
stabilization.
sential for
quality conditions
before BMP implementation
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