Chapter 2: Program
2.2.6
Lesson: Use of constructed wells for moni-
toring ground water is preferable. If ex-
Evaluation, and
isting wells must be used, and are found to
be contaminated, the possibility that the
contamination results from poor construc-
Lesson:
tion or leaking rather than as a result of
Post-BMP
water
n
genera1 aquifer conditions must be consid-
data must be collected for at l e a s t
ered.
two to three years in order to assess the
effectiveness
In the Minnesota
project,
vadose zone monitoring was used to document
Post-BMP multiple-year monitoring,
that the high level of pesticide contamination in
along with adequate
monitoring,
wells was due primarily to point sources of
in demonstrating water
changes
pesticides (commercial pesticide application
that could be associated with land
in
services).
Idaho, Florida, Oregon, Vermont, and
projects. It is also expected to be a useful
Example: Sampling of irrigation and domestic
RCWP, which is now
technique in
wells in the Nebraska RCWP project resulted in
conducting its
water quality monitor-
inconclusive results, partially because of local
ing.
contamination and lack of information about
well construction.
Example: As a consequence of reduced funding,
the planned post-project evaluation of the moni-
The South Dakota RCWP project util-
toring
in the Virginia project was
ized
constructed for
Although
and the effectiveness
will not be docu-
expensive, the project had an effective water
mented.
quality monitoring program in which the results
were directly related to the RCWP.
Lesson: Long-term monitoring (six to
years) with grab samples taken every two
2.2.6.6 Spatial and Temporal
weeks is sufficient to document water qual-
Considerations for M
ity trends in a stream that exhibits at least
a 40% change in
concentrations.
Lesson: Monitoring is needed at the field,
farm, or subwatershed level to assess the
Example: The Idaho,
and Utah projects
effects of BMP systems. Short-term inten-
documented greater than 40% change in their
sive monitoring studies of
pollutant concentrations using grab samples
should be included to help understand
taken two times per month.
physical processes and to provide a basis
for assessing the Ionger-term, overall effec-
tiveness of the project.
Laboratory and
quaiity as-
pro-
surance and quality control
Example: The Minnesota
project used
grams that include data evaluation and
vadose zone
to determine that splitting
verification for precision and accuracy are
application of nitrogen did little to reduce
soil nitrate levels
essential elements of a successful water
monitoring program.
Example: South Dakota used a master field site
and several farmers' field
Alabama and Oregon
determine the effectiveness of
found that
for fecal
analysis was especially
of
rapid die-off and the high natural
of
The Vermont
used
the data
the
level to document that in-
of
under
creasing the
waste
fecal coliform
The Idaho and Florida projects imple-
eis in the monitored streams.
mented extensive
procedures for
chemical and biological data
and lab
and analysis techniques.
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