238
M. Lang and D.W. Eckhoff
of magnitude above their limiting concentrations, virtually assure the dominance of
phytoplankton in photosynthesis in the aquatic zone. On the other hand, because of the
temperatures reached during the summer months, phytoplankton populations decline to
levels which are not generally considered to be inhibitory to the types of water sport
activity envisioned by the City of New York.
In contrast it is quite evident by the data presented here that heterotrophic activity
has a definite undesirable impact on turbidity levels in Jamaica Bay. Other analytical
endeavours (Eckhoff, et al 1970) have demonstrated that the discharge of organic
materials to the Bay has resulted in significant depressions of ecological diversity due to
high accumulations of organic materials in the sediments, as well as characteristic
dissolved oxygen depressions during the warmer months of the year.
Prior to the Jamaica Bay Study, the city had commenced with a program of improving
the performance of its water pollution control facilities. In addition, the Jamaica Bay
Study activities included the development of an optimum program for the control of
combined sewer overflows. When these two programs are fully implemented, it is
anticipated that the reduction of BOD discharged to the Bay will be in the range of 75
per cent of the present quantities. This should succeed in virtually eliminating any
dissolved oxygen problems, and it is anticipated that the clarity of the waters of Jamaica
Bay will increase substantially. The relationship expressed by equation (5) suggests that
summertime planktonic levels will even decrease additionally as transparency (d )
improves.
The concept of management of water quality through control of nutrient discharges to
the Bay was also explored. However, this alternative would involve a heavy financial
commitment, and the success of a limited program, such as nutrient removal from
dry-weather wastewater flows, could not be guaranteed because of the many other
sources of nutrients (including precipitation).
CONCLUSIONS
1. The eutrophication of Jamaica Bay, although of somewhat different character than
that occurring in fresh waters, is quite pronounced and presently considered to be a
detriment to the utilization of the Bay for many recreational purposes.
2. The high phytoplankton populations observed, principally during the winter
months, do not appear to be a significant causative factor in the occurrence of relatively
high turbidities in the critical summer recreational period. It is apparent that
heterotrophic activity is principally responsible.
3. Improved performance of water pollution control facilities and the implementation
of a program of control of combined sewer overflows will result in a reduction of BOD
discharges to the Bay of approximately 75 per cent. This should abate heterotrophic
activity substantially and effect marked improvements in both dissolved oxygen levels
and water clarity. Coliform concentrations should likewise fall to acceptable levels.
4. The anticipated improvement in water clarity should serve to further reduce the
already low summertime phytoplankton densities.
5. The control of nitrogen and phosphorus discharges to Jamaica Bay could also effect
marked improvements in water quality, through limitation of phytoplankton populations
and reduction of overall biological activity. However, this would require heavy financial
commitments, and at this point in time the incremental benefits cannot be quantitatively
M. Lang and D.W. Eckhoff
of magnitude above their limiting concentrations, virtually assure the dominance of
phytoplankton in photosynthesis in the aquatic zone. On the other hand, because of the
temperatures reached during the summer months, phytoplankton populations decline to
levels which are not generally considered to be inhibitory to the types of water sport
activity envisioned by the City of New York.
In contrast it is quite evident by the data presented here that heterotrophic activity
has a definite undesirable impact on turbidity levels in Jamaica Bay. Other analytical
endeavours (Eckhoff, et al 1970) have demonstrated that the discharge of organic
materials to the Bay has resulted in significant depressions of ecological diversity due to
high accumulations of organic materials in the sediments, as well as characteristic
dissolved oxygen depressions during the warmer months of the year.
Prior to the Jamaica Bay Study, the city had commenced with a program of improving
the performance of its water pollution control facilities. In addition, the Jamaica Bay
Study activities included the development of an optimum program for the control of
combined sewer overflows. When these two programs are fully implemented, it is
anticipated that the reduction of BOD discharged to the Bay will be in the range of 75
per cent of the present quantities. This should succeed in virtually eliminating any
dissolved oxygen problems, and it is anticipated that the clarity of the waters of Jamaica
Bay will increase substantially. The relationship expressed by equation (5) suggests that
summertime planktonic levels will even decrease additionally as transparency (d )
improves.
The concept of management of water quality through control of nutrient discharges to
the Bay was also explored. However, this alternative would involve a heavy financial
commitment, and the success of a limited program, such as nutrient removal from
dry-weather wastewater flows, could not be guaranteed because of the many other
sources of nutrients (including precipitation).
CONCLUSIONS
1. The eutrophication of Jamaica Bay, although of somewhat different character than
that occurring in fresh waters, is quite pronounced and presently considered to be a
detriment to the utilization of the Bay for many recreational purposes.
2. The high phytoplankton populations observed, principally during the winter
months, do not appear to be a significant causative factor in the occurrence of relatively
high turbidities in the critical summer recreational period. It is apparent that
heterotrophic activity is principally responsible.
3. Improved performance of water pollution control facilities and the implementation
of a program of control of combined sewer overflows will result in a reduction of BOD
discharges to the Bay of approximately 75 per cent. This should abate heterotrophic
activity substantially and effect marked improvements in both dissolved oxygen levels
and water clarity. Coliform concentrations should likewise fall to acceptable levels.
4. The anticipated improvement in water clarity should serve to further reduce the
already low summertime phytoplankton densities.
5. The control of nitrogen and phosphorus discharges to Jamaica Bay could also effect
marked improvements in water quality, through limitation of phytoplankton populations
and reduction of overall biological activity. However, this would require heavy financial
commitments, and at this point in time the incremental benefits cannot be quantitatively