Problem Documentation Sample Timing
Both
and storm conditions should be monitored to identify the problem
and its source using chemical/physical monitoring.
water chemistry and
discharge samples should be taken at approximately 28-day intervals or more
often. Monitor especially during the time of the year when the problem is noted.
All
samples need not be at low flow or at a regular interval. The purpose
is to characterize low flow conditions. Guidance on the timing of biological
monitoring should be available from the state water quality agency.
Storm sampling can be used to document the
of hydrologic and
pollutant impacts.
should coincide with runoff events associated with
applications, manure applications, irrigation season, or other activ-
ities thought to be responsible for the water quality problem. For animal lots with
minimal control of waste, the timing of the storm is not critical, since the problem
should be relatively easy to detect.
Storm samples should be taken during the rise, peak, and falling stream levels
during runoff events. Seasonal and climatic factors should also be considered. If
is substantial, monitoring during this time is important. Also consider
historic rainfall patterns. Drought conditions will most likely be unrepresentative
so problem documentation monitoring may have to be extended to represent
typical wet weather and pollutant loading conditions.
Examples of Problem Documentation Monitoring
Water quality problem identification monitoring should seek first to specify
pollutants and conditions responsible for the impairment to the designated use.
Once the water quality problem is identified, the severity of the problem can be
assessed. Clearly identifying the specific pollutant and assessing the problem
assists land treatment staff in identifying critical areas and targeting
difficult to locate. Die-off for bacteria is relatively rapid in cool seasons (an hour
to a week or more), and sources such as animal and human waste can generally be
defined quickly with a thorough survey and careful monitoring below suspected
watershed pollutant sources.
The Utah and the Oregon RCWP projects monitored above and below dairies to
determine the magnitude of the bacterial contamination (Spooner et al. 1991).
Sources of sediment pollutants are often more widespread and more difficult to
identify than sources of bacteria. For instance, sediment can originate from
cropland, ditches, gullies, roads, forests, and streambanks. Sediment can also re-
enter the water column as a result of scouring in streams and recirculation in lakes.
sediment survey and sediment budget are needed to identify watershed sediment
sources, determine sediment delivery, and quantify the relative contribution of
each source.
In the Idaho RCWP project, streambed quality and trout reproductive capacity
were reduced by siltation, and transparency was reduced by high suspended
sediment concentrations. At the onset of the project, agricultural sources were
identified as the primary cause of reduced streambed quality. Further analysis
showed streambank erosion was also a major contributor of sediment load. The
influx of sediment from streambank erosion made it
to document the
effectiveness of
From the project estimates, the sediment
4.4
Previous Page
