Chapter 2:
Analysis
n Lesson: Sources of sediment are often more
2.2.6 Wafer Quality Monitoring,
widespread and difficult to isolate than
Evaluation, and Reporting
bacteria sources. Sediment can originate
(continued)
from cropland, ditches, gullies, roads, for-
ests, and streambanks and can re-enter the
water column via scouring in streams and
Lesson: Source of bacteria causing con-
n
recirculation in lakes. Sediment surveys
tamination in shellfish or recreational wa-
and budgets are needed to identify sources,
ters are generally not difficult to locate.
determine delivery, and quantify
Die-off for bacteria is relatively rapid and
contributions of each source.
sources can generally be located by moni-
toring below suspected animal waste
A survey of sediment sources and
sources.
monitoring of streambanks in the Vermont pro-
ject indicated that one subwatershed contributed
Example: The Utah and the Oregon projects
Hay and
the most sediment to the St
monitored above and
dairies to determine
sediment delivery was not as much of a problem
the magnitude of the bacterial contamination.
as previously thought
operations
The
project had
in the Vermont project were monitored to deter-
high erosion rates in areas with steeply sloping
mine the relative magnitude of bacterial pollut-
and targeted these areas for critical area
ant s o u r c e s .
counts decreased
treatment Huge gullies were also identified as
after dairy sources were treated.
significant, but sediment delivery from these
sources
not estimated. Overall, the effec-
tiveness of the critical area designation is
Example: The Alabama project, with few ani-
tionable since the relative magnitude
and
mal operations, documented dramatic decreases
sediment sources is not
in fecal coliform levels
the lake as operators
closed or improved animal waste management
The Illinois project found that both the water-
shed and lake sediments were sources of the
turbidity problem in Highland Silver Lake.
be the most widespread and difficult to
erosion
a
source of
sediment in the Idaho and Nebraska projects.
identify and quantify. Sources include
Identification and
of
ero-
commercial fertilizer, animal waste, soil
sion in the
project
to docu-
reserves, and atmospheric deposition.
menting and treating the problem. The Idaho
Streambeds, lake sediments, and ground
project would have benefited from increased
water can also release stored nutrients.
emphasis on
erosion control.
In Vermont,
phosphorus
loading to St
was believed to
from hay
adjoining wet-
2.2.6.3
land, and
runoff. Area soils also
contributed to the total
P load_ A
Lesson: Objectives should be clear and
budget of major sources was needed deter-
mine potential for reducing lake or bay P levels.
should provide a general guide for the
experimental design of the water quality
Sources of high nitrate levels in do-
and land treatment monitoring program.
mestic wells in Minnesota included animal
The primary objectives of NPS watershed;
and
The topography is
projects should be evaluation of use
limestone with extensive sinkhole formations.
port status, trend detection, or
Sinkholes were thought to be primary
to ground water until
studies
en
showed rapid leaching of nitrate from fertilized
cropland. Further study indicated that
should be targeted for
Example: Monitoring in South
showed
that animal operations contributed significantly
to nutrients in surface water and
ap
plied to
affected ground water.
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