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 Title Page
 Table of Contents
 Introduction
 Cruz Bay
 Chocolate Hole
 Appendix






Group Title: Water pollution report
Title: Report on the status of water quality in Cruz Bay and Chocolate Hole, St. John
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Permanent Link: http://ufdc.ufl.edu/UF00096174/00001
 Material Information
Title: Report on the status of water quality in Cruz Bay and Chocolate Hole, St. John
Series Title: Water pollution report - Caribbean Research Institute ; 9
Alternate Title: Status of water quality in Cruz Bay and Chocolate Hole, St. John
Physical Description: 4, 6 leaves : ill. ; 28 cm.
Language: English
Creator: Grigg, David I
VanEepoel, Robert P
Caribbean Research Institute
Donor: unknown ( endowment ) ( endowment )
Publisher: Caribbean Research Institute
Place of Publication: Christiansted, USVI
Publication Date: 1971
Copyright Date: 1971
 Subjects
Subject: Water quality -- Virgin Islands of the United States -- Cruz Bay   ( lcsh )
Water quality -- Virgin Islands of the United States -- Chocolate Hole   ( lcsh )
Genre: non-fiction   ( marcgt )
Spatial Coverage: United States Virgin Islands
 Notes
General Note: At head of title: Government of the Virgin Islands, Department of Health, Division of Environmental Health, Water pollution report, contracted by Caribbean Research Institute, College of the Virgin Islands.
General Note: "January, 1971 (2nd printing, June 1971)."
Statement of Responsibility: David I. Grigg and Robert P. vanEepoel.
 Record Information
Bibliographic ID: UF00096174
Volume ID: VID00001
Source Institution: University of the Virgin Islands
Holding Location: University of the Virgin Islands
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 09459995

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Table of Contents
    Front Cover
        Front Cover
    Title Page
        Title Page
    Table of Contents
        Table of Contents
    Introduction
        Page 1
    Cruz Bay
        Page 2
        Page 3
        Page 4
    Chocolate Hole
        Page 5
    Appendix
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
Full Text






CARIBBEAN RESEARCH INSTIrUT"t


W ,ATR POLLUTION REPORT NO. 9

TILL STATUS OF WATER QUALITY IN CRUZ MAY

AUND CH COLATL lIOLL, ST. JOHN

David I. Grigg and Robert P. vanEepoel
January, 1971
(2nd Printing June, 1971)










GOVERNMENT OF THE VIRGIN ISLANDS

DEPARTMENT OF HEALTH, DIVISION OF ENVIRONMENTAL HEALTH


WATER POLLUTION REPORT

Contracted By

CARIBBEAN RESEARCH INSTITUTE

COLLEGE OF THE VIRGIN ISLANDS










REPORT ON

THE STATUS OF WATER QUALITY IN CUZI BAY

ANDCHOCOLATE HOLE, ST. JOHN


David 1. Grlgg and Robert P. vanEepoel

January, 1971
(2nd Printlig June 1971)











CONTENTS

Pag

I. INTRODUCTION I

II CRUZ BAY 2

m. CHOCOLATE HOLE 5

IV. APPENDIX 6







I. INTRODUCTION

This reports a follow-up evaluatona of two bays previously studied.1 It should

be interpreted In that contest and with reference to the original report. The present

evaluation ti based on quantutaUve data collected in November and December of 1970,

and on aerial photographs and snorkella investigations of both bays. We wish to thank

Mr. Fred Nicholson, Director of the Bureau of Public Health laboratorleo for once ag&in

performing th. bacteriological analyes.






















1

Brody. R. W., D. I. Grigg, D. M. Haup and R. P. valEepool,
Report on Estuarine Envirnament at Cruz Bay. St. John, Goverment of the
Virgin Islands, Department of Health. Division of Enviroonmeital Health:
"Phase T Report. A Study of the Effects of Pollutants o the Waters and Sediments
of COru Bay", October, 1969; "Phase I Report, A 8 udy of the Waters, Sediments,
and Blots of Chocolate Hole, St. John, with Copa on to Cruz Bay, St. John",
January, 1970.






11. CRU7 BAY

Water quality data were gathered in Cruz Bay on November 20, 1970 and again on

December 1, 1970 and are summarized in Table 1. Between these times rough seas had

stirred up the bottom of the bay considerably. Tits was evident by increased turbidity

and large amounts of benthic grasses, algae, bivalve mollusks and sponges washed up on

the beach. This very high energy situation must have occurred shortly before our inspection

on December 1, 1970 because all f the stranded organisms were still alive at that lime.

Other effects of this surge action were apparent and are evident in Table I.

The temperature was lowered at all stations, reflecting the intrusion of colder

water from Pillabury Saund. Salinity was made more uniform throughout the bay; the

range was compressed from 35. ppt 37.5 ppt measured on November 20, 1970 to

35. 0 ppt 36.4 ppt. At all stations except #38 (deepest in the creek), pH was higher on

the second occasion. There was no change at Station #38. At all but one staton (027)

there was an increase In suspended solids and Secchi depth was reduced at several stations.

Visibility was obviously reduced it the northeast portion of the harbor around Government

House Point and the ferry dock. In fact, the reduction (compared to summer, 1969) at

Station 027 off the tip of the deck was very striking: from 4.2 meters (bottom) to 2.5

meters. Color was normal around the channel light and along the reef south to Golge Point

and in a arro- bnsd east of the reef. Elsewhere colnr was noticeably affected by the

milky cast ol suspended sand fines. Snorkeling investigation showed that there was indeed

suspended sand and organic particulates In the water. Much scouring has occurred In the

back reef area and this area was also the source of the large number ol benthic organisms

found washed up on the beach.







It is apparent that seasonal changes in sea and weather signlficantly affect the

water In Crus Bay (Table 2). For this reason, it is more likely that reliable indications

of algnlficant or permanent changes in water quality would be gained by comparing the

data from winter, 1969 and winter, 1970. When this is done, the most striking difference

Is that dissolved oxygen in both areas was higher this December than a year ngo: 6.2

mg/] as compared with 5.7 mg/I in the harbor and 5.G mg/I versus 4.3 mg/l in the

creek. A definite redaction in aquatic visibility is apparent, especially at Stations

h14, 21, 23, 27. This ita the area around Govsenmet LHouse Point. The average Seche

dLac visibility in the harbor (2.7 meters) is apparently reduced compared to 3.2 lneters

(average bottom depth) last year. Visibility is very much reduced compared to summer

and fall of 1969. Now the bottom is visible only in that section north and west of

Stations #4, 5. 6, 1I, 18 and in water less than 1.6 2 meters along the bench. Along

the north shore the bottom can be seen only in less than I meter. On the other hand,

most stations checked in the ureek aea showed an increase in water clarity. The

improvement here is also evident from a boat and from aerial photos.


There are now many boats anchored in the bay than n year ago, and a small

floating dock has leen placed off the beach to service ferry boats. Boat traffic In

and oat of the bay is noticeable heavier. In the creek the water color is still very

bld and in the area of Stations '34 and 236, there was a great deal of oil. The sept

od or of enage was very bad here on November 20, 1970 and It was noted that where

the sewer lice comes out of the bulkhead near Otation .;30 the elbow was broken loose

and sewage was being discharged upward out of the breaook to the water surfnee. Of

six samples evaluated for fecl coliforms and streptorocci this was the only positive

sample, with 2 fecal colform per 1oo ml,


-3-







In summary, Crus Bay water quality on the whole is worse now than it was a

year ago. Accompanying this reduction of quality, however, has been a relative Improve-

meat in the quality of the oreak water. Presently, it seem likely that most of the change

la due to seasaMl wave action in Crau Bay. This has di1turbed bottom Benmenta In the

outer bay and promoted uumiual nixing between the waters of the harbor aend te creek.

This mbidK has resulted, because of the uaual nequIty ina these water masses, In a

relative Improvement of creek water quality at the expense of a simultaneous reduotlon

In harbor water quality. It is therefore difflaut to determine if Crui Bay has eastalaed

say permanent, log-tert cuhbge in water quality.


-4-







m. CHOCOLATE HOLE

Data collected in Chocolate Hole in November are given In Table 3. The bay

hbows very few changes alnoe our survey a year ago. Water color, visibility and

bottom organisms seem to be nla as good condition now as then and the bottom can still

be Been throughout the bay. The only quantitative observation of note s a sip cantly

lower salnity at Statio #7, where the pood conecta to the bay. This saljntty depression

is undoubtedly caused by outflowing pond water which, considering the aumseul amoonta

of rainfall during the past year, most now be quite brackleb. Monthly averages for water

quality data are gives In Table 4.


There are now 4-5 boats anchored in the bay and littering of the se bottom

is Increasing: several cans aad other items were noted. Except for these, no adverse

ohabges were noted.


-5-










2001



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TABLE 1

CRUZ BAY, ST. JOHN
WATER QUAIJTY DATA, NOV.-DEC., 1970
Fecal Fecal
SecOhi Suspended Colitfor Strep
Temp. Sal. D. O. Depth Solids per per
Staton Date C. . pH MG/L C Sat. M- MG/L I00 ML 10A Ml

4 11/20/70 28.0 37.5 8.1 6.4 102 B 27.2 0 0

12/1/70 27.1 36.0 8.3 6.3 97 B 32.2 -- -

14 11/20/70 27.9 37.5 8.1 6.9 H4 3.0 17.6 --

12/1/70 27.0 36.2 8.3 6.3 97 2.8 20.6

18 11/20/70 28.0 37. 86.1 6.8 108 B 8.6 0 0

12/1/70 27,1 36.0 8.3 6.2 95 B 16.1

21 12/1/70 27.2 35. D 8.2 6.2 95 2.8 13.0

23 12/1/70 27.1 36.0 8.3 G.3 97 2.3 23.7

27 11/20/70 2B.0 35.6 5.1 0.3 99 3.0 10.1

12/1/70 27.2 36.2 B.3 6.1 94 2.5 13.9 0 0

A VeRAr E 27.5 3.r. 8. e. 2.7-B 1a.9 G 0

30 11/20/70 28.0 37.5 8.1 5.8 92 2.0 0.0 2 0

12/1/70 26.8 36.0 8.2 6.1 94 2.3 18.0

34 12/1/70 24.6 36.4 8.2 5.5 85 -- 16.2

36 11/20/70 28.0 36.7 8. L 5.4 86 0.8 14.1 0 0

12/1/70 26.6 36.2 8.2 5.4 82 -- 19.1

38 11/20/70 28.2 35.7 8.0 5.3 83 1.25 13.7 0 0

12/1/70 26.6 36.4 8.0 5.3 80 -- 21.3

AVERAGE 27.3 36.4 8.1 5.6 86 1.6 14.6 I1 0





CRUZ BAY, ST. JOHN
?MONTHLY AVERAGES FOR SIX WATER QUALITY PARAMETERS
SECCHI FzCAL COLIFORM
TEMP. SAL. D. 0. DEPTH AND STREP
STATION DATE O C. .. pl_ G/L METERS c.LS/100 ML
4 AUG/69 29.5 36.2 -
SEP/69 29.2 36.5 8.3 6.0 3.8 8
DEC/69 27.2 36.5 8.3 6.1 3.8 0
NOV/70 28.0 37.5 8.1 6.4 3.8B 0
DEC/70 27.1 36.0 8.3 6.3 3.8B -
14 AUG/69 29.5 36.3 -
SEP/69 29.3 36.6 6.3 5.2 3.5B 31
DEC/69 27.2 36.5 8.4 5.9 3.5 -
NOV/70 27.9 37.5 8.1 5.9 3.0
DEC/70 27.0 36.2 8.3 6.3 2.8 -
18 AUG/69 29.5 36.4 -
SEP/69 29.5 37.5 8.3 5.7 1.88 4
DEC/69 27.0 36.5 8.4 5.8 1.88 7
NOV/70 28.0 37.5 8.1 6.8 1.88 0
DEC/70 27.1 35.0 8,3 6.2 1.88
21 AUG/69 29.5 36.3 -
SEP/69 29.4 37.0 8.3 5.6 3.2B 48
DBC/69 27.1 36.5 8.4 5.7 3.2B
NOV/70 -
DEC/70 27.2 36.0 8.2 6.2 2.8
23 AOG/69 30.0 36.0 -
SEP/69 29.6 36.6 8.3 4.7 2.78 15
DEC/69 27.3 36.5 8.3 4.7 2.7B 11
NOV/70 -
DEC/70 27.1 36.0 8.3 6.3 2.3
27 AUG/69 30.0 35.6 -
SEP/69 28.5 36.6 8.3 5.5 4.2B 7
DEC/69 27.2 36.5 8.4 5.9 3.9 0
NOV/70 28.0 35.6 8.1 6.3 3.0 0
DEC/70 27.2 36.2 8.3 6.1 2.5
30 AUG/69 30.0 28.2 -
SEP/69 29.8 36.2 8.2 4.3 1.9 12
DEC/69 26.9 36.5 8.3 5.3 2.2 -
Nov/70 28.0 37.5 0.1 5.8 2.0 2
DEC/70 26.8 36.0 B.2 6.1 2.3 -
34 AUG/69 30.0 35.9 -
S SEP/69 29.7 36.6 8.2 4.3 1.1 79
D.C/69 27.3 36.5 8.3 3.8 1.:
NOV/70 -
DEC/70 26.6 36.4 8.2 5.6
36 AUG/69 30.0 36.0 -
SEP/69 29.8 36.0 8.2 4.3 1.1 80
DEC/69 27.3 36.5 8.3 4.4 1.5
NOV/70 20.0 36.7 8.1 5.4 0.8 0
DBC/70 26.6 36.2 8.2 5.4
38 AUG/69 29.5 36.8 -
SEP/69 29.6 37.1 8.1 4.0 0.8 20
DBC/69 27.4 36.6 8.3 3.7 1.8 3
NOV/70 28.2 35.7 8.0 5.3 1.3 0
DEC/70 26.6 36.4 8.0 5.3 -







TABLE .

CHOCOLATE HOLE, ST. JOHN
WATER QUALITY DATA, NOV. 13, 19T7

Recthi Light Extinction
Temp. Sal. Depth (Ft-CaDdleA i
saUti- C. %. pH /MlM % 9Rt. M. Too Meter To Bottom

7 28.5 34.8 8.2 5.1 80 B -- -

16 2895 -- 8.2 6.0 94 B 2,600 705

18 28.1 36.0 8.2 6.3 98 B 3,.20 745

20 28.1 -- 8.1 6.2 98 B 330 655

22 28.0 36.0 8.1 6.0 95 B 3.000 61,640

AVTRAGE 28.2 35.6 8.2 5.9 93 B 2.275 936






TABLE 4

CHOCOLATE HOLE. ST. JOIN
MONTHLY AVERAGES FOR SIX WATER (WALITY PARAMETERS


Sal.
Station Date i Temp. %ct

Oct./69 30.0 36.7
2 Nov./69 26.5 36.1
Dec./69 27.6 36.4
Nov./70 -

Oct./69 29.5 -
5 Nov./69 28.4 36.2
Dec./69 27.8 36.4
Nov./70

Oct./69 -
7 Nov./69 28.7 36.0
Dec./69 28.2 36.4
Nov./70 28.5 34.8

Oct./69 30.0 36.3
18 Nov./69 28.6 36.2
Oec./69 27.4 36.4
Nov./70 28.1 36.0

Oct./69 29.6 36.7
20 Nov./69 28.8 36.2
Oec./69 27.7 36.
Nov..70 28.1 -

Oct./69 29.6 36.7
22 NOV./69 26.5 36.2
Dec./69 27.8 36.3
Nov./70 28.0 36.1

Oct./69 30.0 36.7
26 Nov./69 28.5 36.1
Dec.169 27.8 36.4
Nov./70 -

Oct./69 29.4 36.7
30 Nov./69 28.4 36.2
IHc./69 27.8 36.4
Nov./69

Oct./69 30.0 36.7
PI Nov./69 28.7 35.4
Occ./69 30.8 37.8


Oct./69 30.5
P2 Nov./69 28.0 35-7
Dec./69 30.6 38.3


m ...


Fecal Strep
Scchi Depth s Coliform
Meters Cell /100ol

8 48
8 3
B0



S 0

B 0
0o
B 0
B 8





B 6
B 6

B 0

& 0
D 0



B 14
8 8

N 82




B 20
o 0



3



19




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