A STUDY OF WATER CIRCULATION IN PARTS
OF GREAT SOUTH BAY, LONG ISLAND
Prepared by
Field Operations Section, Technical Services Branch
Division of Water Supply and Pollution Control
Robert A. Taft Sanitary Engineering Center
Cincinnati, Ohio
and
Water Supply and Pollution Control Program
Region II, New York City
Department of Health, Education, and Welfare
U. S. Public Health Service
February 19&2
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A STUDY OF WATER CIRCULATION IN PARTS
OF GREAT SOUTH BAY, LONG ISLAND
INTRODUCTION
As a result of public, State, and local governmental Interest in
the water quality of Great South Bay, Long Island, the Public Health
Service has cooperated with the New York State Health Department and the
Long Island State Bark Commission under the coordination of Mr. A. F.
Dappert, Executive Secretary of the Hater Pollution Control Program, of
the former agency, in a study of certain areas in Great South Bay.
The interest of the agencies cooperating in this study was stim-
ulated by the presence of marine plants which were carried up on the
beaches in August of i960 in the Babylon Area of Great South Bay. The
water was observed to~have a grayish cast and have an unpleasant odor.
The interest of the New York State Health Department in the situation
resulted in a request for the Public Health Service to investigate the
matter.
Conferences with the named organizations of the State of New York
indicated that while there is background information available to explain
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the i960 nuisance conditions that Indicated that It vas desirable for a
field study to obtain quantitative data that might be made available If
future marine plants were to cause nuisance conditions in future years.
It vas agreed that the Public Health Service's participation in
the cooperative investigations wuld be limited to the study of water
mass movement and circulation. Field operations vere conducted during
the months of August, September, and October of 196l. This report presents
the results of these field studies.
ACXROWLEDQ^aiTS
The Public Health Service is deeply appreciative of the un-
remitting and sincere cooperative efforts of the various agencies of
the .State of New York during the course of its field operations.
The entire study program vas ably coordinated through the efforts
of Mr. A. F. Eappert of the Hew York State Water Pollution Control Board.
Mr. Richard Boyce of the Long Island State Bark Commission pro-
vided our field crev vith several experienced, competent and Interested
boat operators.
Mr. Harold Udell of the New York State Conservation Consulssion
provided a boat and more than adequate dockage.
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SCOPE OF FIELD STUDY
Because of other field survey commitments during this period, it
vas possible to assign only three persons to this particular study. In
order to obtain the best possible picture of vater mass movement and
circulation vith the limited staff and facilities available, it was
decided to use a dye tracer technique to obtain information on the
circulation and movement of water masses. The dye technique is partic-
ularly useful in determining rates of renewal end rates of flushing.
Because of the possible Importance of a limited amount of m.1xlng between
the waters of the Bay itself and the waters in the small coves fringing
the north shore, it vas felt that this technique vas particularly useful
In the situation existing in Great South Bay.
She field operations vere concentrated in the area of Great South
Bay lying vest of the Bay bridge. Babylon Cove vas studied in some
detail, both because of Its importance as a purported particular problem
area because it may be regarded as typical of the small coves fring-
ing the north ehore of Great South Bay. Some effort vas also directed,
toward that part of the bay adjacent to Fire Island Inlet; the purpose
of this effort was to determine hov far into the Bay ocean water comes
on a tidal excursion.
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DISCUSSION OF FIELD STUDY
Great South Bay lies on the south shore of Long Island and is
separated from the Atlantic Ocean by a narrow sand bar which is at
places only a few hundred yards vide. The Bay is approximately 25 nau-
tical miles long and averages about three miles in vidth. The navigational
features of the Bay and its bathymetry are shoved in U. S. Coast and Geodetic
Chart 578 vhich is reproduced as Figure 1 of this report. It may be noted
that the Bay is extremely shallow and has a mean depth of approximately
four feet. Only in the main navigation channels and in the region near
Fire Island Inlet are depths over 15 feet found.
The area of Great South Bay vest of the Bay bridge is about seven
miles long and tvo nautical miles wide and is roughly about three feet
in mean depth. The deepest part in this area is about nine feet. Biera
are large areas vhich have depths of less than two feet. The tidal range
throughout the Bay is one foot or less. Fire Island Inlet is the primary
source of nev ocean water for Great South Bay. The tidal currents through
Fire Island Inlet are quite strong.
Tha entire system represents an offshore bar built estuary, typical
of estuaries on the south Atlantic coast of the United States and on the
Gulf Coast, but relatively in North Atlantic States. The shal-
lowness and of large fresh«*»ater inflows, as is typical of such
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systems, indicates vind and tide driven circulation end a lack of signif-
icant stratification. A comparison of tidal range, mean depth and surface
area indicates that a volume of water equivalent to about one-quarter of the
Bay volume must enter through Fire Island Inlet in one tidal cycle. One
critical question to be answered, is how far into the Bay does this new
marine offshore water penetrate.
Field Survey Techniques
The tracer technique used in this study involving a dye, P>ifv!amino-Bf—
is a recent development of the Chesapeake Bay Institute at The Johns Hopkins
University. This dye is a brilliant red dye used in food coloring and
lipstick preparations. It is detectable by its fluorescence down to con-
centrations as small as .02 ppb. For field survey purposes it is procured, ad
a *t0$ solution in acetic acid; thia solution is diluted wlti water at tho
ifrmnjMng area before the dump; after suitable dilution it is. released -over-
board by siphoning from the mixing container.
Detection of Khodamine-B is accomplished by a Turner Fluorometer
which is equipped with a continuous flow cell. The- water that is sampled
is pumped, from over the side through the fluorometer and discharged over-
board. The instrument reads and records instantaneously. Figure 2 is a diagram
of the sampling fluorometric system. The underway sampling device, as used
in this study, is essentially a tube with a screen in front of it.
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During sampling the boat moved steadily at Beven knots vhile
vater was being pumped and the data recorded. Runs vere made on a
straight line between navigation markers; some of these markers vere
the standard navigation markers existing In the Bay, some of these vere
buoys set by the investigators. Positions of all navigation markers
and on occasion that of the boat wore fixed by sextant bearings on
landmarks.
Eye fluoresence vaa recorded on continuous strip charts, a sample
of vhlch is reproduced in,Figure 3. Charts vere set to run at & rate of
one-half inch per minute. The location of data on the strip chart was
keyed Into field location by notes and log sheets.
Since the dye fluoresence is a function of temperature, such vere
taken after the vater had passed through the fluoroaster. Temperature
values are therefore probably not absolute of the vater temperature, but
they provide good relative values.
Because of the importance of vinds and other veather conditions
weather data vere obtained from the Veather Bureau for the survey period*
Thft veather data used are those obtained at the Idlevlld Airport at the
permanent veather bureau station there; con imitative advice from a
meteorologist indicated that these results vould Indicate conditions
in the general area as voll as any limited number of temporary veather
stations that be established by the field staff •
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Field Surrey Procedures
The power supply for the fluorameter ceme from a generator vhich
was attached, to the engine of the boat; in order to supply satisfactory
power for fluorometer operation It was necessary to operate the boat
constantly at a motor speed vhich drove the boat at seven knots. The boat
that was used, had a shallow draft which permitted vork In large areas of
the Bay.
Two procedures vere used for dumping the dye. These may be claused
as either a line dump or as an area dump. In making a line dump the boat
moved In a straight line from one navigation marker to another vfalle the
dye vas siphoned over the stem at a carefully regulated flov. One or
store passes vere made depending on the quantity of dye to be dumped and
the distance between the markers. In matting an area dump, a marker buoy
was set In the center of tts area in which the <2ye vas to be discharged.
The dump vas made vith the boat moving In a slovly expanding circle about
the starker buoy; the rate of flow and the boat speed vere regulated so that
the dye vas more or less uniformly dispersed over a 50 to a 100 foot in
diameter circle. Concentrations in the dumping area vere not measured
immediately after the ducp vas made,, since the high concentrations existing
at that time would contaminate the .fluarameter and make it necessary to
clean the Instrument before any further measurements could be made at very
lov. concentrations.
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In a very few hours after a dye dump was mads, all visible trace
of the dye bad disappeared from the water, ami the only way to detect
the presence of the dye vas by fluoromatrlc measurement. On each day,
therefore, it vas necessary to search for the dye patches belug examined
at that particular time. A Beries of search patteraB for the different
parts of the Bay were developed, and these standard patterns were run
on each day until the dye &urg> vas located. The search pattern was then
terminated, and a pattern was run uhlch was designed to characterize the
dye distribution. The distribution of dye in a particular patch v&b
characterised fence or twice a day, depending upon how long It took to
find the patch and upon weather conditions. A particular dump vaa studied
for as long as detectable concentrations existed. The typical pattern
for the characterization of a dye dump In Babylon Cove is shoved in
Figure it-.
It vas often necessary to have two dumps in operation at once.
This meant that on occasion there wee some interference on the fringes
of the two dumps. However, it is believed that no serious Interference
did occur in the dumps which supplied data used in the preparation of
thiB report.
TVift dye dumps which were sufficiently heavy to be detectable for
2b hours or longer are listed in Table I. The conditions surrounding
dump are discussed in a later section of this report*
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TABLE I. LIST OF DYE DUMPS
Estimated
Quantity (lbs)
Initial
Name of Dump
Type
Day
Time
Cone.
'FII) Fire Island Inlet
Area
9/1^
0800
10
100 ppb
(BB) Bay Bridge
Strip
9/18
1130
5
500 ppb
.Ll) Lindenhurst I
Strip
9/19
1830
5
300 ppb
12.) Lindenhurst II
Area
10/2
1630
0.4
1«00 ppb
GIC) Grass Island Channel
Area
9/28
1430
0.2
150 ppb
A) Amityvllle
Area
10Jl
1215
0.2
100 ppb
BC) Babylon Cove
Area
9/28
9/27
1330
0.2
200 ppb
,SC) State Channel
Strip
1430
0.1
150 ppb
Fire Island Inlet
Bay Bridge
Lindenhurst I
Lindenhurst II
Grass Island Channel
Amityville
Babylon Cove
State Channel
Wind at Time of Dump
Direction Speed
W
£
SW
wsw
SW
Gala
Calm
Light
Moderate
Moderate
Strong
Light
Strong
Tide at Time of Dump
Slack before flood current.
Beginning of flood.
Beginning of ebb.
End of flood.
Beginning of ebb.
Strength of flood.
High water.
Strength of ebb.
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ANALYSIS OF DATA
From field data the dye distribution for each search pattern on
each day is established. From the observed distributions, water circula-
tion patterns and rates of renewal are deduced.
The notes from the log sheets are transferred to the Btrip charts
to identify each run. In order to characterize properly the distribution
along a run it was necessary to add special marks in addition to those
vertical ordinates already present prior to digitizing the data. These
special marks, identified by SP, may be seen by referring to Figure 3*
Data collected on 9/l9> 9/20; 9/27/ 9/28, and 9/29 were digitized on the
Benson-Lehner Oscar J. It was not possible to digitize all the data in
the time available; however, those runs not digitized on the Oscar J were
read by eye and value8 converted to dye concentration. Those records
digitized on the Oscar J permitted a more detailed analysis of the
distributions as opposed to the records read by eye.
A typical digitized set of data is showed in Table II. The boat
courses are then plotted for each day using landmarks and navigational
markers together with sextant angles obtained during the survey. Tabulated
data of the dye concentrations are entered on the charts along each course
run together with the starting and ending times. In order to obtain
distributions representative of synoptic results the plotted courses
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TABLE II. EXAMPLE OF DIGITIZED DATA
Ordinate and
Special Mark Units
Sequence In Oscars
0001 135
0002 187
0003 19^ — SPECIAL 0.5 (Refers to distance in
0004 170 tenths of inches of record the
0005 1^0 value 19^ osc&r units is located from
0006 _ 129 0002 ordinate.)
0007 129
0008 125
0009 185
0010 280
0011 294 SPECIAL O.k
0012 2jk
0013 309
0014 371
Hie actual dye concentrations are obtained from the following
relationship for this particular set of data.
-3
Ejye Concentration (ppb) *» (Oscar Units x 10 )
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are reviewed with regard to space and time. When the spacial distribution
of courses were such, and the time interval over the distribution was
small, the tabulated data were contoured.
In order to ascertain the validity of the contoured distributions
the area within each contour is determined by planimetry and the total
quantity of Rhodamine-B present is determined. It must be remembered
that the initial mass introduced is conserved and that at later stages
though the original amount is still present in the system the concentra-
tions may be low enough to exceed the limits of detectabllity.
By viewing some of the figures it will become obvious that during
certain dumps the peak concentration appears to have increased with the
passage of time* Ihis effect may be interpreted in one of the following
ways:
(1) The peak concentration was not measured on previous runs.
(2) Limited sampling in the creeks revealed high concentrations
and with the passage of time this mass of dye may have been
displaced Into the area studied.
A more comprehensive detailed analysis would be necessary to conclude
which one or both of the above interpretations would be valid for a partic-
ular dump. It is felt,' however, that this type of analysis would not change
the dye quantity or distributions enough to warrant greater detail* The
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rate of renewal and mass movement in a particular area and the character
of turbulent diffusion deduced from the distributions presented hare
suffice to substantiate conclusions arrived at regarding the area studied.
DISCUSSION OF RESULTS
Theoretical Aspects
Estuarine systems are often regarded as bodies of vater composed
of numerous vater masses in turbulent motion. The turbulent regimes of
such systems are exceedingly complex and are not at present amenable to
characterization by analytical mathematical techniques or by direct field
measurement of turbulent motion. These regimes are best described
mathematically as stochastic processes, vhile field measurements are
limited to the characterization of properties related to the turbulence
regime.
The complexity of mathematical analysis of estuarine systems is
complicated, by the fundamentally different nature of the Lagrazigian and
Eulerian frames of reference. A fluid in motion as part of a larger
body of fluid may be regarded as existing in a Lagrangian frame of
reference. For convenience in discussion this frame aay be regarded as
a moving Cartesian coordinate system which has as its origin the tip of
a vector in a fixed Cartesian coordinate system, which is descriptive
of an Eulerian frame of reference. The mathematical relationship between
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these two frames of reference has not been clearly established, and a
mathematical description of occurrences based on one frame of reference
is not necessarily descriptive of happenings in the other frame of
reference.
These considerations are also extremely important in establishing
the usefulness of field measurements for characterizing turbulent systems.
2here are two different types of measurements which can be made vlth
limited resources in such systems. First, a series of measurements can
be taken at fixed locations vlth in a system. Current meter, readings are
a typical example of this type of sampling. Second, measurements can be
taken continuously across a section of the system» The dye data obtained
in this study are examples of this type of measurement. Both types of
measurements are directly related to the Euleriaa frame of reference]
only if these are made on a very fine time and space sampling grid can
they provide useful information about the Lagrangian frame* These con-
siderations indicate that detailed measurements at a few fixed points are
of little utility in characterizing a Lagrangian process. What is needed
are many measures covering large areas. Fran such measures, if they are
t.ntcpn rapidly enough, synoptic distributions of a property can be deter-
mined for different times. The motion of the Lagrangian field of the
property and the rate of interchange of this field with its environment
can be deduced.
The advantages of a tracer technique combined with underway
gnmpUng are quite apparent for this type of study* A unique, easily
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detectable property- Is Imparted, to a water mass at a time and place of
choice. The entire history of this water mass (or masses) can then be
followed to the limits of time and equipment available.
As has been pointed out previously, a turbulent regime is most
usefully regarded as a stochastic process. In doing this, any set of
measurements is regarded merely as one realization of the process being
sampled. A precise description of such a process i9 not possible vith
an extremely limited number of observations. The data on which this
report is based represent an extremely limited sampling of the system,
and the results must be regarded as estimates, not definitive values.
Field, observations of the results of a dye release provide in-
formation about tvo important aspects of water movement.
First, by following the center of mass of the dye, the advective
motion of the water mass in which the dye was released can be traced.
This will delineate the general circulation of the system and show how
rapidly "new" water reaches the dyed region by advective processes. A
strong advective regime in an area subject to pollutlve discharges would
indicate that pollutant materials should be removed, from the area rather
rapidly, and that pollutant build-up should not be a problem.
Second, by characterizing dye distributions In Lagrangian frames
of reference, the Intensity of turbulent mixing and diffusion can be
determined.; from these the efficiency of water renewal and waste removal
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through turbulent or "eddy" diffusion processes can be estimated. A
qualitative estimate of the efficiency of turbulent mixing can be obtained
from merely examining the character of the charted dye distribution.
Intense turbulent mixing would exhibit secular trends in vhich the dye
is rapidly dispersed over a vide area and in vhich the dye distribution
itself changes rapidly and loses any characteristic shape it may have
had initially. Theoretical approaches to quantitative estimates of
turbulent mixing and eddy diffusion have not been sufficiently successful
to provide a means for the Interpretation of field observations in terms
of the degree of intensity of turbulent processes.
For the purposes of this report turbulence mixing parameters are
usefully expressed as a ratio expressing efficiency of turbulent diffusion
in terms of the observed dye concentrations in the dyed areas. This may
be expressed mathematically as
Sj,(o,t) = 100 (1 - Ct) ,
C
o
where E^,(o,t) = efficiency of turbulent mixing for the time
interval o to t,
C =¦ initial maximum dye concentration,
o
C = maximum dye concentration at time t.
w
This expression can be readily interpreted as the percentage of
"new" water in the system t days after the dye release. The same type
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of calculation may be made using the total amount of dye present in a
particular region of the Lagraagian field at several time intervals
after the initial release* The vise of this technique was not possible
in many of the releases made in this study because the large shoal areas
of Great South Bay did not permit complete characterization of several
releases.
General Circulation West of the Bay Bridge
Information on the general circulation of this part of Great
South Bay was provided by most of the releases listed in Table I. No
attempt is made to discuss the history of each dye release In detail,
only those aspects of each release which appear of particular significance
or interest are discussed.
The dye release listed as "Bay Bridge" dump is of particular interest
in this serleB. This release vas a strip dump made Just after low water
at Babylon. The dump vas made in one pass along the navigable length of
the Bay Bridge, about 25 feet vest of ths bridge piers. At the time of
the release there vas a moderate easterly breeze, estimated at about 12
knots, and there were a few vhitecaps visible in open vater areas. It
would be expected that the combination of wind and tide existing when
this release was would favor the advective transport of the tagged
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water mass into the western part of the Bay, and that this would represent
the most favorable conditions for the advection of "new" water into this
section of the Boy.
The progress of this release is 6hown in Figures 5-10. These results
illustrate several significant aspects of the water mass movement in this
part of the Bay. There are apparently at least two different circulatory
regimes associated with this region. One lies on the North side of the Bay
and has very little advective motion other than that related to tidal move-
ment. Water on the South side of the Bay in this region has an apparent
westward advective drift, probably about a mile per day exclusive of the
tidal oscillation. The turbulent regime, as deduced from the dye distribu-
tions, is not intense enough to cause thorough mixing of the water in this
part of the Bay in a short period of time. The turbulent mixing efficiency
in the North part of the distribution is about 5$ per tidal cycle, indicating
that about 10 days would be required to renew the water in this region by
turbulent mixing. The turbulent mixing efficiency in the South part of the
distribution is somewhat higher, around 15-20$ per tidal cycle.
It is interesting to note the effects of very stormy weather on dye
releases in this part of the Bay. The close passage of a hurricane in the
Atlantic Ocean caused very high tides combined with strong winds and rain
in the period of September 20-22. Two releases were in the Bay at that
time, the Bay Bridge dump Just discussed and a strip dump made from
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Lindenhurst to the E. Fox Creek Channel on the evening of September 19.
Some limited, sampling on September 20 shoved the presence of both dumps
in about the same positions as they were the day before. It was not
possible to reconmence sampling until September 27. At this time dye from
both dumps vas found: that from the Bay Bridge dump v&s widely dispersed
west of the Bridge, and there vas a significantly high concentration of dye
in Babylon Cove; dye from the Lindenhurst dump vas present in the area
vhere it was dumped originally and there were additional quantities in the
vicinity of Strong's Point.
An area dump off Lindenhurst Light one week later exhibited the same
general properties. Figures 15-23 exhibit the results of this as veil as
of other dumps. It is observed that a significant quantity of the dye
collected in the vicinity of the mouth of Strong's Creek.
It should be noted, however, that a large part of this end of the
Bay vas not sampled because of the extensive shoal areas; it is quite
possible that part of this dump as well as of other dye releases entered
some of these regions. It is suspected that the AmityvlUe release vent
toward the shoal areas of South Oyster Bay. This dump, made at high tide
off Amityville, vas not found to the east or south of the dump area, and
it is probable that it did move on into the shoals to the vest.
An area dump at the mouth of Grass Island Channel, opposite Babylon
Cove, at the beginning of ebb tide at Babylon exhibited advective and
turbulent characteristics similar to the Bay Bridge release.
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It is apparent that State Channel and the rest of the Intracoastal
Waterway Channel play ar. Important part in water circulation ve3t of the
Bay Bridge. Two releases were made in this channel, one at the navigation
lights west of the Capt.ree Island Bridge, and one at the navigation lights
between Grass Island Channel and E. Fox Creek Channel. Both releases were
made while the tide was ebbing. Both releases were carried east along the
channel and did not return. While data was being obtained on releases in
Fire Island Inlet at slack before flood, the end of State Channel at
Snakehill Channel was sampled. No significant quantity of dye was found
to enter State Channel under these conditions.
Several conclusions may be drawn from the results of these dye
releases. First, both advective and turbulent diffusion processes are
quite restricted in the part of Great South Bay west of the Bay Bridge.
Time in excess of one week is probably required under favorable wind
conditions for renewal of Bay waters in the areas adjacent to Babylon
Cove and the mouths of Neguntatogue and Strong's Creek. A slow movement
of water to the west in the southern part of this section of the Bay does
occur; while the further progress of this water is not known, it may enter
State Channel to the west of Grass Island and leave the Bay on ebb tide,
being replaced by water entering through Snakehill or Dickerson Channel.
Even winds of near hurricane force do not apparently cause major changes
in the circulation of this part of the Bay.
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Water Renewal In Babylon Cove
One dye release was made in the confines.of Babylon Cove at high
tide. A strong WSW vlnd was blowing at the time of the release, and
there were numerous whitecaps in the Cove. This release was made in a
circle about 100 feet in diameter and consisted of 0.2 pounds of dry dye
equivalent. The history of this dump is showed in Figures 12-21, and 23.
This release was traced for eight days, when it became necessary to
terminate the survey.
These figures show clearly that Babylon Cove has a well-defined
water mass that does not mix rapidly with the adjacent Bay water. It
is apparent that there is very little advective motion other than the
tidal action, and that the Cove-Bay turbulent mixing regime is quite
weak.
From the secular changes in the dye distribution it can be seen
that periods well in excess of one week, possibly as much as two weeks
or more, may be required for fairly complete renewal of the water in
Babylon Cove.
Penetration of Ocean Water Into Great South Bay
A dye release equivalent to 10 pounds of dry dye was made at
slack water before flood current off the "sore thumb" in Fire Island
Inlet. This release was distributed uniformly in a band 200 feet long
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across the width of the channel. This dump was followed to its farthest
point of penetration into the Ray and part way back out before motor
trouble required suspension of operations. Traces of this release were
found on the following day.
The results of this release are presented in Figures 2k and 25.
It can be seen that "new" ocean water penetrates into the Bay proper only
through Snakehill Channel. In the other channels, the tagged water
progressed only as far as Saltaire to the east and Sextor. Island to the
north. Water entering the Bay through Snakehill Channel actually only
reached the shallows in the southern part of the Bay. The day after the
dye release, part of the tagged water had penetrated through the island
barriers both to the east and to the north. Tagged water was generally
present in the southern part of the Bay east of the Bey Bridge and had
penetrated beyond the Bay Bridge and into State Channel in very small
concentrations.
These results indicate that the renewal of Bay water by "new" ocean
water occurs very slowly, so slowly that it is probably a misnomer to state
that any "new" ocean water reaches the Bay except small amounts in the
vicinity of Snakehill Channel. By the time ocean water has been in the
system long enough to reach the Bay proper, it has mixed so thoroughly
and in such smnii quantity with water already present in the Bay, that
it has lost any characteristics which might differentiate it from "Bay water."
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CONCLUSIONS
1. The dye studies in the western part of Great South Bay have revealed
a regime of extremely limited mixing and circulation.
2. Adyective transport is quite small along the northern shore of the
Bay, and in some regions is practically nonexistent.
3. Turbulent mixing is also apparently quite ineffective in aiding mixing
and flushing processes.
4. Detailed studies in Babylon Cove indicated that mixing between Babylon
Cove and the adjacent parts of the Bay is so limited that periods in
excess of a week would be required to renew a significant part of the
Cove water even under the most favorable wind cord.itions.
5. These results may be generalized to state that circulation in parts
of Great South Bay is sufficiently poor that the build-up of organic
materials, or any other materials, could occur in some areas with the
existence of suitable wind and weather conditions.
6. Limited water circulation in parts of Great South Bay could be a
highly significant factor in the development of the anomalous con-
ditions observed during August i960.
SUMMARY
1. The Public Health Service has conducted dye tracer studies of water
mass movement circulation in parts of Great South Bay.
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2. These studies vere based upon the fluorometric determination of
Rhodamine-B, a tracer dye detectable in minute quantities.
3. Field studies were limited to that part of Great South Bay vest
of the Bay Bridge. Babylon Cove was studied in some detail.
4. The results show a pattern of highly limited circulation and mixing
throughout the area studied.
5. Mixing of Babylon Cove water with the adjacent Bay water is extremely
slow.
6. New ocean water does not penetrate into the area studied. Only after
several tidal cycles does any water originally at Fire Island Inlet
reach west of the Bay Bridge, and then in extremely s.nall quantity.
7. The limited circulation indicates the probability of the build-up
of putrefiable and other materials in some parts of the Bay.
8. The limited circulation characteristics of Great South Bay may be
a highly significant factor in the development of the anomalous
conditions observed in August i960.
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LIST OF FIGURES
Figure 1 - Photographic Reproduction of a Section of U. S. Coast and
Geodetic Survey Chart 578.
Figure 2 - Diagram of Sampling and Fluorometric System.
Figure 3 ~ Example of Fluorometer Recording Chart.
Figure 4 - Typical Series of Boat Courses Run to Characterize Distribu-
tions of Rhodamine-B Eye in Babylon Cove. Numbers in
Parenthesis Indicate Time.
Figure 5 ~ Rhodamine-B Dye Distribution in the Afternoon on 9/l8/6l
at a Depth of 2.0 Feet.
Figure 6 - Rhodamine-B Dye Distribution on the Warning of 9/l9/6l at
a Depth of 2.0 Feet. Time of Lov Tide at Babylon 1206
Hours.
Figure 7 - Rhodamine-B Dye Distribution in the Afternoon on 9/l9/6l
at a Depth of 2.0 Feet.
Figure 8 - Rhodamine-B Dye Distribution on the Morning of 9/20/61
at a Depth of 2.0 Feet. Time of High Tide at Babylon
07^5 Hours.
Figure 9 - Rhodamine-B Dye Distribution in the Early Evening on
9/27/61 at a Depth of 2.0 Feet.
Figure 10 - Rhodamine-B Dye Distribution in the Early Morning of
9/28/61 at a Depth of 2.0 Feet.
Figure 11 - Rhodamine-B Dye Distribution at Noon on 9/28/61 at a
Depth of 2.0 Feet.
Figure 12 - Rhodamine-B Dye Distribution on the Morning of 9/29/61 at
a Depth of 2.0 Feet.
Figure 13 - Rhodamine-B Dye Distribution in the Afternoon on 9/29/61
at a Depth of 2.Q Feet.
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3j
Figure l4 - Rhodsraine-B Eye Distribution on the Morning of 10/2/61
at a Depth of 2.0 Feet.
Figure 15 - Rhodamine-B lye Distribution in the-Afternoon on 10/2/61
at a Depth of 2.0 Feet.
Figure 16 - Rhodanine-B Dye Distribution on the Morning' of IO/3/0I
at a Depth of 2.0 Feet.
Figure 17 - Khodamine-B Dye Distribution in the Afternoon on 10/3/61
at a Depth of 2.0 Feet.
Figure 18 - Rhodamine-B Eye Distribution on the Morning of IO/U/61
at a Depth of 2.0 Feet.
Figure 19 - Rhodamine-B Dye Distribution in the Afternoon ori 10/4/61
at a Depth of 2.0 Feet.
Figure 20 - Hhoderaine-B Dye Distribution on the Morning of IO/5/61
at a Depth of 2.0 Feet.
Figure 21 - Khodamine-B Eye Distribution in the Afternoon of 10/5/61
at a Depth of 2.0 Feet.
Figure 22 - Rhodamine-B Dye Distribution on the Morning of 10/6/61
at a Depth of 2.0 Feet.
Figure 23 - Rhodamine-B Eye Distribution in the Afternoon of 10/6/61
at a Depth of 2.0 Feet.
Figure 2k - Locater Chart Showing Fire Island Inlet Eye Dunp Position
on 9/l4/6l and Courses Run to Determine Penetration of
Sea Water into Great South Bay.
Figure 25 - Rhodamine-B Dye Distribution in the Afternoon on S>/l5/6l
at a Depth of 2.0 Feet.
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PAGE NOT
AVAILABLE
DIGITALLY
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DIAGRAM OF SAMPLING AND
FLUOROMETRIC EQUIPMENT
FIGURE 2
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SPECIAL READING CL
SCALE 30 X
EXAMPLE SHOWING A TYPICAL FLUOROMETER RECORD
OBTAINED DURING THE SURVEY
FIGURE 3
-------
TYPICAL SERIES OF BOAT COURSES RUN
TO CHARACTERIZE DISTRIBUTIONS OF
RHODAMINE B DYE IN BABYLON COVE
(NUMBERS IN PARENTHESIS INDICATE TIME)
FIGURE 4
HUN TO BAY BRIDGE.CAN "5" IN OICKERSON
j*. CHANNEL. BACK TO N"6* IN OICKERSON CHANNEL,
(1102) TO THE BAY BRIDGE.
NAUTICAL HILI9
-------
RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
DATE
9/18/61, AFTERNOON
DEPTH
2.0 FT.
FIGURE 5
-------
RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
TOWER
-------
RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
DATE
9/19/61 AFTERNOON
DEPTH
2.0 FT.
HIGH TIDE
1846 RM.
FIGURE 7
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RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
TOWER
($TEEL)QT0WER (WOOD)
nautical miles
DATE
9/20/61 MORNING
DEPTH
2.0 FT.
HIGH TIDE
0745 A.M.
FIGURE 8
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RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
TOWER
(STEE L)Q TOWER IWOOD I
DATE
9/27/61. EVENING
DEPTH
2.0 FT.
MAuTiCAL MilCS
FIGURE 9
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-------
-------
-------
-------
RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
DATE
10/2/61.MORNING
DEPTH
2.0 FT.
FIGURE 14
-------
0.08
RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
DATE
10/2/61.AFTERNOON
DEPTH
2.0 FT.
FIGURE 15
-------
RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
DATE
IO/3/6I .MORNING
DEPTH
2.0 FT.
FIGURE 16
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-------
-------
-------
RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
DATE
10/5/61 MORNING
DEPTH
2.0 FT.
FIGURE 20
-------
RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
DATE
10/5/61, AFTERNOON
DEPTH
2.0 FT.
FIGURE 21
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BABYLON
SPIRE O
OSTACK
OTANK
OCUP
LINDENHURST
RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
TOWCR
istecd^towcr (woooi
DATE
10/6/61.MORNING
DEPTH
2.0 FT.
FIGURE 22
-------
N
BABYLON
SPIRE O n
TANK
OSTAC*
OTANK
OCUP
lindenhurst
k
0.08
,• SArflTAPOGUE PT.
0.08
06
i BABYLON COVE
S^PAWAMS PT.
r\ nl
RHODAMINE B DYE DISTRIBUTION
(CONCENTRATION IN ppb)
TOWER
STEEL)QT0WER (WOOD)
NAUTICAL MtLCS
DATE
10 /6/6I .AFTERNOON
DEPTH
2..Q FT.
Fl
SURE 23
-------
LOCATER CHART SHOWING FIftE ISLAND INLET DYE DUMP
POSITION ON 9/14/61 AND COURSES RUN TO DETERMINE
-------
RHODAMINE
(CONCENTI
0ISTRI8UTI0N
IN ppb)
M1i(A taut
' OATE 19/15/6) AFTERNOON
OEfLH ' ' t? P_£J
FIGURE 2 5
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HERMAN t H1LLBB0S. M. O.
COMMISSIONS*
STATE OF NEW YORK
DEPARTMENT OF HEALTH
REGIONAL OFFICE
58 church Street
Whits plains n. Y,
William r. Donovan, m.
/rmional Health Director
¦REPORT ON F/CTOJIO AFFECTING THE POLLUTION OF GREAT SOUTH BAY,
LONG ISLAND, N.Y. WITH SPECIAL REFfOTGE TO ALGAE BLOOMS
a joint sunmary renort prepared by the New York
State Department of Health, the United States
Public Health Service and State conservation and
park agencies
Great South Bay is rich in nutrients favoring the growth of algae,
and from time to time, such growths become so numerous as to constitute
"bloomS", which are concentrations of algae dense enough to be visible to
the naked eye. Such blooms have always occurred and on occasion have become
so dense and widespread as to cause oublic concern. The most recent such
occurrences were in 1958 and I960, Large areas of algae blooms existed,
dissolved oxygen in the water was depleted, fish were killed and decomposing
algae were moved on shore producing highly objectionable odors, A study
was made during the summer and fall of 1961 to investigate the various factors
which might cause the algae blooms or other deleterious conditions, and to
determine if any control measures were feasible.
These investigations involved the determination and analysis of
various physical, chemical and biological factors existing in most of
Great South Bay, with special relation to their effect upon excessive growths
of algae.
Several agencies were concerned with these investigations and it was
agreed in order to orevent duplication of efforts and to utilize to best
adv?.ntage the resources of each agency that portions of the study were to be
allocated to each unit. Biological, physical-and chemical studies of the
bay itself were carried out by State conservation and park agencies. The
study of the water mass movement and circulation within certain portions of
the bay was made, by the United States Public Health Service and the survey
of ground and surface water tributary to the bay was done by the New York
State Health Department, In addition to these agencies, valuable assistance
was given by the Suffolk County Health Department and the Unit ed States
Geological Survey,
As a result .of these studies, .'voluminous data were compiled*' This
summary report is based' on;the findings end pon^lueipi^S-^Jeyelooed by fche
nartioJ wiping
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Summary
1, There are large numbers of plartfcton, including algae, in all portions
of the Bay. Species characteristic of vaters polluted by organic material
are especially numerous in regions where organic wastes are most likely to
be discharged,
2., Phosphates and nitrates are both essential nutrients for algae and
other plankton. The phosphates are especially high, and the nitrates low.
Both are indices of organic pollution, and to a considerable extent have
their source in domestic sewaga, industrial wastes, duck farms, and leachings
from agricultural fertilizer,
3, Frora the average annual rainfall of 46,5 inches per year, some 21
inches is discharged to Great South Bay, All but a small fraction of this
originates as ground water flow which is polluted by the leachings from
septic tanks and cesspools. Some 95^ of the 432,000 population of the area
dispose of sewage by this means. During and after rainfalls, most of the
storm water runoff is carried via pipes into streams and canals tributary
to the bay. A large amount of organic material is picked up during the flow
of this storm water over the surface of the ground and along street gutters.
4, The high phosphate content of the near shore bay waters is due in
large part to phosphates derived from detergents. It is estimated that
over 54 tons per year of nhosphates from this source is discharged-to bay
waters. Non-detergent phosphorus originates in domestic sewage,- industrial
wastes,' artificial fertilizer and from duck wastes^
5, Nitrates have as their principal source the contamination of ground
water by sewage and other wastes,
6, The abnormally low nitrate-phosphate ratio is attributed to the
utilization by nlankton of most of the nitrates, leaving an excess of
¦phosphates, Nitrates are therefore a limiting factor in the production of
algae blooms. As nitrate* contribution increases with population growth
and continued disposal of sewage effluents to the ground water aquifer,
the algae population and troubles associated therewith may be expected to
increase,
7t Tidal flow into and out of the bay and tidal ranges in the bay
have not been altered significantly during the past 25 years,
8. The small depths of water in the Bay, its large area,' and the
general hydrography prevent rapid flushing under normal conditions. Wind
has a substantial influence upon ourrents and flow in the Bay, and rapid
changes in the characteristics of the bay vaters are believed due chiefly
to wind effects. Dye studies showed that circulation in parts of Great
South Bay is sufficiently poor that the buildup of organic materials could
occur in some areas with existance of suitable wind and weather conditions,
9, Fresh water contribution to the Bay ^averages about 260 million
gallons per day, or about one million gallons per day per square mile of
tributary drainage area. This reduces the salinity. In the Bay proper,
excluding the Inlet^ the salinity is about 75^ of that in the ocean. No
marked changes in salinity have occurred in recent years. Salinity and
other factors varied rapidly at different stations in the Bay. Such
variations were not found to affeot the total population of plankton, but
may influence the dominance of one or another species;
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- 3 -
10. No evident relation was found between production of algae blooms
and meterological events but some combination of these and other factors
may well contribute to excessive blooms and particularly to the objectionable
conditions associo.ted"«i.th their decay.
11. The excessive algae blooms of the Labor Day weekend ip I960,
attributed to Cladoohora, a bottom attached algae, cannot be assigned as due
to any soecial factor. Such blooms are a local phenomenon likely to occur
anywhere so long as the oresent enrichment of the bay waters continues. No
such blooms vrere observed in 1961 when meterological conditions were
substantially similar to those in i960.
12. There have occurred so-called "good" and "bad" years with respect
to the occurrence of excessive algae growths in the Bay. Previous reports
and the present investigations have been able to assign no specific causes
for these. There are always sufficient nutrients reaching the Bay to
suooort a large plankton modulation, and some combination of conditions may
at anytime "trigger off" excessive algae blooms. Such combinations are
unknown, probably different on different occasions, and unpredictable. The
only cure is to remove the excessive discharge to the Bay of contaminants
containing large amounts of nutrients,
13• Bacterial indices of human pollution, 33 coli counts and Biochemical
Oxygen*Demand, are generally low in the bay waters, but indicate questionable
quality in certain local bays and coves,
14*' The largest counts of plankton and the highest ohosphate
concentrations were-found either in waters adjacent to regions of greatest,
population.density, as at Babylon Cove westward to Nassau Shores, or in
waters subject to.pollution by duck wastes or agricultural fertilizers.
Conclusions
The waters of Great South Bay are abnormally enriched by nutrients
having their nrincinal origin in organic wastes produced by human activities.
These wastes come largely from sewape effluents reaching the ground water
which is discharged to the Bay. 7.'here the soil is mirous and the subsurface
disposal systems are operating adequately, the wastes ?.re easily leached
into the ground water. If the soil is not conducive to the use of subsurface
systems, overflows will occur which find their way into the surface streams.
Organic nitrogen, ooliform organisms and synthetic detergents all indicate
that human wastes are entering the watercourses. In the eastern oartidn of
the Bay a significant amount of nutrients come from duck farms.
Contamination of the bay waters from the sources indicated provide
smole nutrients to. support the large plankton ponulation. Algae of all kinds
will continue to flourish and to produce occasional exceesivo blooms so long
as the ground and surface waters continue to receive the liquid wastes
described. As population density increases, the situation may be expected to
become worse*
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- 4 -
Recommendations
The most practicable and effective meens for improving the quality
of the waters of Great South Bay to render them fully suitable for the
best uses to which they may be out is the construction of sewerage systems
and sewage treatment plants to collect and remove the domestic and industrial
wastes, with disposal of the plant effluents in such a manner as to avoid
contamination of the bay waters. This can be accomplished by taking the
effluent from the waste treatment facilities to the ocean waters or returning
it to the ground waters inlands It should be stressed that if the alternative
of replenishing, the ground waters is considered, the wastes must be treated
to a very high degree to prevent the same chemicals mentioned previously from
entering the ground and eventually finding their way to Great South Bay. It
is evident that the construction of sewerage systems and treatment plants for
the entire drainage area tributary to Great South Bay will entail a
considerable period of time. The population of the area will not remain sta+ic
and in the interim it may be necessary to have sewage treatment facilities
constructed for certain snail areas ife. (shopping centers, subdivisions) vdLth
outfalls discharging into tributaries- of Great South Bay, In such cases,'a
high degree of treatment should be required to keep to an absolute minimum
the nutrients entering the bay.,
6/25/62
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