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"works." The tida data (Figure 2, panel H) provided us with information on usual tides for the
waterfront, as well as a storm surge that ocurred on July 17 (winds exceing 45 mph were
recrded at Cape Poge: panel C). The July 17 storm was accmpanied by ranfall of about 1.5
inches (panel E), one effect of which is sen in the sainity data (panel F). There is considerable
quantitative information to be derived from this data set. Since the aquatic monitoring station
was locte nea the mouth of the harbor, it alternately sampled water from inside the harbor and
from outside the harbor, with the reversing tida flow. Beuse many water borne pollutats
move through coasta systems along with freshwater, the flushing out of ranwater contans
information on how certn pollutats could be flushed from the harbor as well. In the
management context flushing is an asset; it represents one measure of the Harbor's capacity to
clease itself. Development of methodologies and software to use monitoring recrds to address
flushing are importt aspets of marketing the electronic hardware itself.
A crucial focus of many environmenta impact studies for residential and commercial
development at the coast is to assess the impact of nutrent discharge on dissolved oxygen in the
reciving waters. A common management. objective is to prevent relate oxygen depletion-hypxia
or anoxia--which strongly alters the ecsystem and leads to loss of fish and shellfish and
production of undesirable odors. The pulse oxygen electrode deployed at Edgarown Harbor
allows convenient and direct monitoring of dissolved oxygen, eliminating the nee to infer it
from nutrent data.
A one month recrd of dissolved oxygen and solar raiation (which drives oxygen production
through plant photosynthesis) is shown in figure 3. Thi~ recrd represents the first substatial
field data set obtaed using this ENDECO/YSI instrmentation. These data indicate, among
other things, that the Harbor showed no inclination toward significat oxygen depletion at any
stage of tide, day or night, or after prolonged cloudiness.
We have also been able to make use of electronic data to address another major concem--fec
contamination of Harbor water from marne toilets. Although it is presently ilegal to discharge
mare toilets into nea coasta waters, enforcement of this law is difficult and many yachts do
not have the capacity to hold sewage on board. Given. the proximity of the shellfish beds in
Katama bay to the anchorage of the Inner Harbor, may Edgarown residents were concerned
that the magnitude of fec contamination from boats remained porly defined.
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