OCEANOGRAPHIC BASELINE DATA (1971-72)
FOR THE FORMULATION OF
MARINE WASTE DISPOSAL ALTERNATIVES FOR PUERTO RICO
«-
VOLUME I: MAIN REPORT
^» " ~~ *«»-.
FINAL REPORT-NOVEMBER 1974
ATLANTIC OCEAN
Miunu
F«J»«00
CARIBBEAN SEA
-------
9O2175501A
OCEANOGRAPHIC BASELINE DATA (1971-72)
FOR THE
FORMULATION OF MARINE WASTE DISPOSAL ALTERNATIVES
FOR PUERTO RICO
VOLUME I: MAIN REPORT
FINAL REPORT - NOVEMBER 1974
Prepared For
ENVIRONMENTAL QUALITY BOARD
OFFICE OF THE GOVERNOR
COMMONWEALTH OF PUERTO RICO
Prepared By
OCEANOGRAPHIC PROGRAM
AREA OF NATURAL RESOURCES
DEPARTMENT OF PUBLIC WORKS
COMMONWEALTH OF PUERTO RICO
This study was jointly financed by the Commonwealth of Puerto Rico
and the United States Environmental Protection Agency through a planning
grant under PL 84-660, as amended.
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PREFACE
This report was originally published in limited quantity in
July 1972 by the Area of Natural Resources of the Puerto Rico
Department of Public Works (now Department of Natural Resources).
It has been reprinted for larger distribution by the United
States Environmental Protection Agency with the cooperation of
the Puerto Rico Environmental Quality Board and Department of
Natural Resources.
In an effort to make this report quickly available, no stylistic
changes have been made to the text and maps. Where necessary,
minor corrections have been made to portions of the text
and to some of the figures and tables. However, there still may
be figures and tables that contain incorrect or mislabled station
locations, data points and cruise vectors. The reader is cautioned
to check seeming inconsistencies with the P.R. Environmental
Quality Board.
This report was originally prepared while the Comprehensive Water
Quality Management Plan for Puerto Rico was in the early stages
of preparation and prior to enactment of the Federal Water Pollution
Control Act Amendments of 1972 (P.L. 92-500). Therefore, some
references in this report to primary and secondary treatment facilities
and sites, regional divisions, population projections, etc. may not
be in total agreement with existing laws, regulations, policies, and
reports. The user of this report is cautioned to check with P.R.
Environmental Quality Board for the latest information on these matters
-------
CONTENTS
SECTION PAGE
1 SUMMARY 1.2
INTRODUCTION 1.2
DATA ACQUISITION 1.4
OVERVIEW OF DATA 1.4
Ocean Currents 1.4
Density Structure 1.5
Water Quality 1.5
Coliform Disappearance Rate Studies 1.5
CONSIDERATION OF DILUTION POTENTIALS 1.5
2 INTRODUCTION 2.2
GENERAL 2.2
STUDY OBJECTIVES 2.2
PROJECT ORGANIZATION AND MANAGEMENT 2.4
ACKNOWLEDGEMENTS 2.4
3 THE OCEANOGRAPHIC PROJECT AND THE
WASTEWATER MANAGEMENT PROGRAM 3.2
GENERAL 3.2
CONTEXT FOR PUERTO RICO 3.3
4 GENERAL DESCRIPTION OF STUDY AREAS 4.2
GENERAL 4.2
COASTAL AREA DIFFERENCES 4.3
North Coast 4.3
East Coast 4.4
South Coast 4.5
West Coast 4.6
5 DATA ACQUISITION 5.2
DATA REQUIREMENTS 5.2
FIELD PROGRAM 5.2
ON-STATION PROCEDURES 5.4
Water Depth 5.4
Water Transparency 5.4
Current Measurements 5.5
Water Temperature 5.6
pH 5.7
Meteorological Observations 5.7
Water Sampling 5.7
ANALYTICAL PROCEDURES 5.8
II
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CONTENTS (cont.)
SECTION FAGE
6 CHARACTERIZATION OF THE NEARSHORE PHYSICAL
OCEANOGRAPHIC FEATURES AT THE ELEVEN STUDY
AREAS 6.2
INTRODUCTION 6.2
SAN JUAN 6.3
Description of Study Area 6.3
Hydrodynamic Data 6,3
Hydrographic Data 6.5
Water Quality 6.7
CAROLINA 6.20
Description of Study Area 6.20
Hydrodynamic Data 6.20
Hydrographic Data 6.23
Water Quality 6.24
HUMACAO/YABUCOA 6.40
Description of Study Areas 6.40
Hydrodynamics-Humacao 6.42
Hydrodynamics-Yabucoa 6.44
Hydrographic Data 6.45
Water Quality 6.46
GUAYAMA 6.66
Description of Study Area 6.66
Hydrodynamic Data 6.67
Hydrographic Data 6.71
Water Quality Data 6.72
PONCE 6.86
Description of Study Area 6.86
Hydrodynamics 6.87
Hydrographic Data 6.89
Water Quality 6.90
GUAYANILLA 6.102
Description of Study Area 6.102
Hydrodynamics 6.102
Hydrographic Data 6.107
Water Quality Data 6.108
MAYAGUEZ 6.123
Description of Study Area 6.123
Hydrodynamics 6.124
Hydrographic Data 6.125
Water Quality 6.126
III
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CONTENTS (cont.)
SECTION PAGE
6 (cont.) AQUADILLA 6.137
Descriptions of Study Area 6.137
Hydrodynamics 6.138
Hydrographies 6.140
Water Quality 6.141
ARECIBO/BARCELONETA 6.154
Description of Study Areas 6.154
Hydrodynamics ' 6.154
Hydrographic Data 6.157
Water Quality 6.158
7 APPENDICES 7.1
APPENDIX A - TECHNICAL AND ANALYTICAL
PROCEDURES USED IN THE STUDY 7.1
INTRODUCTION 7.1
TEMPERATURE 7 .1
SALINITY 7.2
DISSOLVED OXYGEN 7.2
BIOCHEMICAL OXYGEN DEMAND 7.3
PHOSPHATE 7.4
SILICATE 7.4
pH 7.4
COLIFORM ORGANISM DETERMINATIONS 7.5
OCEAN CURRENT MEASUREMENTS 7.5
Ekman-Merz Current Meter 7.5
Drogues 7.7
In-situ recording current meter 7.7
APPENDIX B - DATA PROCESSING METHODS
USED IN THE STUDY 7.9
INTRODUCTION 7.9
TEMPERATURE 7.9
SALINITY 7.10
WATER DENSITY 7.10
WATER QUALITY PARAMETERS 7.11
OCEAN CURRENT DATA 7.11
ANALYSIS OF IN-SITU RECORDING CURRENT
METER DATA 7.11
ANALYSIS OF EKMAN-MERZ CURRENT
METER DATA 7.14
APPENDIX C - SAN JUAN (detailed data) *
APPENDIX D - CAROLINA (detailed data) *
APPENDIX E - HUMACAO/YABUCOA (detailed data) *
The tables and figures contained in Appendices C through K are
labeled sequentially, with a prefix indicating the appendix to
which each belongs.
IV
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CONTENTS (cont.)
SECTION PAGE
7 (cont.) APPENDIX F - GUAYAMA (detailed data) *
APPENDIX G - PONCE (detailed data) *
APPENDIX H - GUAYANILLA (detailed data) *
APPENDIX I - MAYAGUEZ (detailed data) *
APPENDIX J - AGUADILLA (detailed data) *
APPENDIX K - ARECIBO/BARCELONETA
(detailed data) *
8 LIST OF REFERENCES 8.1
* The tables and figures contained in Appendices C through K are
labeled sequentially, with a prefix indicating the appendix to
which each belongs.
V
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LIST OF TABLES
TABLE NUMBER
APPENDIX C
C-l
C-2
C-3
C-4
C-5
C-6
San Juan
Current Meter Data, Cruise 1
Speed and Direction of Drogues Between
Each Point, Cruise 2
Current Meter Data, Cruise 3
Wind Observations
Hydrographic Station Data, Cruise 1
Hydrographic Station Data, Cruise 2
PAGE
7.17
7.18
7.21
7.24
7.25
7.29
APPENDIX D
Carolina
D-l Current Meter Data (Ekman-Merz), Cruise 1
D-2 Speed and Direction of Drogues Between
Each Point, Cruise 2
D-3 Current Meter Data, Cruise 3
D-4 Current Meter Data, Cruise 3
D-5 Current Meter Data, Cruise 3
D-6 Hydrographic Station Data, Cruise 1
D-7 Hydrographic Station Data, Cruise 2
7.44
7.45
7.46
7.50
7.54
7.58
7.63
VI
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APPENDIX E
LIST OF TABLES (cont.)
Humacao/Yabucoa
E-l
E-2
E-3
E-4
E-5
E-6
E-7
E-8
E-9
E-10
E-ll
E-12
E-13
APPENDIX F
F-l
F-2
F-3
F-4
F-5
F-6
Current Meter Data, Cruise 1
Current Meter Data, Cruise 1
Speed and Direction of Drogues Between
Each Point, Cruise 2
Speed and Direction of Drogues Between
Each Point, Cruise 2
Current Meter Data, Cruise 3
Current Meter Data, Cruise 3
Current Meter Data, Cruise 3
Wind Observations
Wind Observations
Hydrographic Station Data, Cruise 1
Hydrographic Station Data, Cruise 1
Hydrographic Station Data, Cruise 2
Hydrographic Station Data, Cruise 2
Guayama
Current Meter Data (Ekman-Merz) , Cruise 1
Speed and Direction of Drogues Between
Each Point, Cruise 2
Current Meter Data, Cruise 3
Wind Observations
Hydrographic Station Data, Cruise 1
Hydrographic Station Data, Cruise 2
7.75
7.76
7.77
7.79
7.81
7.83
7.84
7.85
7.87
7.89
7.93
7.96
7.100
7.113
7.115
7.116
7.119
7.121
7.125
VII
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LIST OF TABLES (cont.)
APPENDIX G
G-l
G-2
G-3
G-4
G-5
APPENDIX H
H-l
H-2
H-3
H-4
H-5
H-6
H-7
APPENDIX I
I-l
1-2
1-3
1-4
1-5
1-6
Ponce
Current Meter Data (Ekman-Merz), Cruise 1
Speed and Direction of Drogues Between
Each Point, Cruise 2
Wind Observations
Hydrographic Station Data, Cruise 1
Hydrographic Station Data, Cruise 2
Guayanilla
Current Meter Data (Ekman-Merz), Cruise 1
Speed and Direction of Drogues Between
Each Point, Cruise 2
Current Meter Data, Cruise 3
Current Meter Data, Cruise 3
Wind Observations
Hydrographic Station Data, Cruise 1
Hydrographic Station Data, Cruise 2
Mayaguez
Current Meter Data, Cruise 1
Speed and Direction of Drogues Between
Each Point, Cruise 2
Wind Observations
Hydrographic Station Data, Cruise 1
Hydrographic Station Data, Cruise 2
Dye and Coliform for Mayaguez Bay
7.141
7.144
7.145
7.147
7.149
7.158
7.160
7.161
7.163
7.165
7.167
7.170
7.181
7.183
7.185
7.187
7.191
Dispersion Study
7.195
VIII
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LIST OF TABLES (cont.)
APPENDIX J
J-l
J-2
J-3
J-4
J-5
J-6
Aguadilla
Current Meter Data (Ekman-Merz), Cruise 1
Speed and Direction of Drogues Between
Each Point, Cruise 2
Variations and Averages of Temperatures,
Salinity and Sigma-t
Wind Observations
Hydrographic Station Data, Cruise 1
Hydrographic Station Data, Cruise 2
7.205
7.207
7.208
7.209
7.211
7.215
APPENDIX K
K-l
K-2
K-3
K-4
K-5
K-6
K-7
K-8
K-9
Arecibo/Barceloneta
Speed and Direction of Drogues Between
Each Point, Cruise 1
Drogue Tracking, Cruise 1
Drogue Tracking, Cruise 2
Drogue Tracking, Cruise 2
Wind Observations
Wind Observations
Hydrographic Station Data, Cruise 1
Hydrographic Station Data, Cruise 2
Hydrographic Station Data, Cruise 2
7.227
7.229
7.231
7.233
7.234
7.236
7.238
7.243
7.246
IX
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LIST OF FIGURES
FIGURE NUMBER
SECTION 2
2-1
Project Organization Chart
PAGE
2.7
SECTION 3
3-1
3-2
3-3
Location of Existing Sanitary and Industrial
Treatment Facilities in Puerto Rico 3.8
Main Features of the Proposed Regional
Wastewater Management Program 3.9
Extent of Coastal Shelf Around Puerto Rico 3.10
SECTION 4
4-1
4-2
4-3
Commonwealth of Puerto Rico Vicinity Map
Distribution of Rainfull in Puerto Rico
Annual Frequency of Wind Direction at Four
Coastal Stations
4.7
4.8
4.9
SECTION 5
5-1
Schematic Representation of Sampling Design
5.9
SECTION 6
SJ-1
SJ-2
SJ-3
SJ-4
San Juan
Current Station Locations
Current Vectors, Cruise 1
Current Drogues, Cruise 2
Current Velocity, Cruise 3
6.8
6.9
6.10
6.11
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LIST OF FIGURES (cont.)
SJ-5 Net Flow Current Vectors, Cruise 3 6.12
SJ-6a Hydrographic Station Locations 6.13
SJ-6b Hydrographic Station Locations 6.14
SJ-7 Surface Density (ot), Cruise 1 6.15
SJ-8 Surface Density (ot), Cruise 2 6.16
SJ-9 Density (ot), Central Section 6.17
SJ-10 Water Transparency, Cruise 1 6.18
SJ-11 Water Transparency, Cruise 2 6.19
Carolina
C-l Current Station Locations 6.26
C-2 Current Vectors, Cruise 2 6.27
C-3 Current Drogues, Cruise 2 6.28
C-4 Current Velocity, Cruise 3 6.29
C-5 Net Flow Current Vectors, Cruise 3 6.30
C-6 Net Flow Current Vectors, Cruise 3 6.31
C-7a Hydrographic Station Locations 6.32
C-7b Hydrographic Station Locations 6.33
C-8 Surface Density, Cruise 1 6.34
C-9 Surface Density. Cruise 2 6.35
C-10 Density (ot), Cruise 1 6.36
C-ll Density (ot), Cruise 2 6.37
c~12 Water Transparency, Cruise 1 6.38
C-13 Water Transparency, Cruise 2 6.39
XI
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LIST OF FIGURES (cont.)
Humacao/Yabucoa
H/Y-1
H/Y-2
H/Y-3
H/Y-4
H/Y-5
H/Y-6
H/Y-7
H/Y-8
H/Y-9
H/Y-10
H/Y-lla
H/Y-llb
H/Y-12
H/Y-13
H/Y-14
H/Y-15
H/Y-16
H/Y-17
H/Y-18
Current Station Locations
Current Vectors, Humacao, Cruise 1
Current Drogues, Humacao Site Cruise 2
Current Velocity, Cruise 3
Net Flow Current Vectors, Humacao, Cruise 3
Current Vectors, Yabucoa, Cruise 1
Current Drogues, Yabucoa, Cruise 2
Current Drogues, Yabucoa, Cruise 2
Current Drogues, Yabucoa, Cruise 3
Net Flow Current Vectors, Cruise 3
Hydrographic Station Locations
Hydrographic Station Locations
Surface Density, Cruise 1
Surface Density. Cruise 2
Density, Central Section, Humacao,
Cruise 1 and 2
Density ot, Central Section, Yabucoa Site,
Cruise 1
Density ot, Central Section, Yabucoa Site,
Cruise 2
Water Transparency, Cruise 1
Water Transparency, Cruise 2
6.47
6.48
6.49
6.50
6.51
6.52
6.53
6.54
6.55
6.56
6.57
6.58
6.59
6.60
6.61
6.62
6.63
6.64
6.65
XII
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LIST OF FIGURES (cont.)
Guayama
Gm-1 Current Station Locations 6.73
Gm-2 Current Vectors, Cruise 1 6.74
Gm-3 Resultant Net Flow Vectors, Cruise 1 6.75
Gm-4 Current Drogues, Cruise 2 6.76
Gm-5 Current Velocity, Cruise 3 6.77
Gm-6 Net Flow Current Vectors, Cruise 3 6.78
Gm-7 Net Flow Current Vectors, Cruise 3 6.79
Gm-8a Hydrographic Station Locations 6.80
Gm-8b Hydrographic Station Locations 6.81
Gm-9 Surface Density, Cruise 1 ' 6.82
Gm-10 Surface Density, Cruise 2 6.83
Gm-11 Density, Central Section, Cruise 1 and 2 6.84
Gm-12 Water Transparency, Cruise 1 6.85
Ponce
P-l Current Station Locations 6.91
P-2 Current Vectors, Cruise 1 6.92
P-3 Current Drogues, Cruise 2 6.93
P-4a Hydrographic Station Locations 6.94
P-4b Hydrographic Station Locations 6.95
p-5 Surface Density, Cruise 1 6.96
p-6 Surface Density, Cruise 2 6.97
XIII
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LIST OF FIGURES (cont.)
P-7
P-8
P-9
P-10
Gn-1
Gn-2
Gn-3
Gn-4
Gn-5
Gn-6
Gn-7a
Gn-7b
Gn-8
Gn-9
Gn-10
Gn-11
Gn-12
Gn-13
Density, Cruise 1
Density, Cruise 2
Water Transparency, Cruise 1
Water Transparency, Cruise 2
Guayanilla
Current Station Locations
Current Vectors, Cruise 1
Resultant Net Flow Vectors, Cruise 1
Current Drogues, Cruise 2
Current Velocity, Cruise 3
Net Flow Current Vectors, Cruise 3
Hydrographic Station Locations
Hydrographic Station Locations
Surface Density, Cruise 1
Surface DEnsity, Cruise 2
Density, Central Section, Cruise 1
Density, Central Section, Cruise 2
Water Transparency, Cruise 1
Water Transparency, Cruise 2
6.98
6.99
6.100
6.101
6.109
6.110
6.111
6.112
6.113
6.114
6.115
6.116
6.117
6.118
6.119
6.120
6.121
6.121
XIV
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LIST OF FIGURES (cont.)
Mayaguez
M-l
M-2
M-3
M-4
M-5a
M-5b
M-6
M-7
M-8
M-9
Ag-1
Ag-2
Ag-3
Ag-4
Ag-5a
Ag-5b
Ag-6
Ag-7
Ag-8
Ag-9
Ag-10
Ag-11
Current Station Locations
Current Vectors, Cruise 1
Resultant Net Flow Vectors, Cruise 1
Current Drogues, Cruise 2
Hydrographic Station Locations
Hydrographic Station Locations
Surface Density, Cruise 1
Surface Density, Cruise 2
Density, Cruise 1
Density, Cruise 2
Aguadilla
Current Station Locations
Current Vectors, Cruise 1
Resultant Net Flow Vectors, Cruise 1
Current Drogues at Aguadilla Site
Hydrographic Station Locations
Hydrographic Station Locations
Surface Density, Cruise 1
Surface Density, Cruise 2
Density, Cruise 1
Density, Cruise 2
Water Transparency, Cruise 1
Water Transparency, Cruise 2
6.127
6.128
6.129
6.130
6.131
6.132
6.133
6.134
6.135
6.136
6.142
6.143
6.144
6.145
6.146
6.147
6.148
6.149
6.150
6.151
6.152
6.153
XV
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LIST OF FIGURES (cont.)
Arecibo/Barceloneta
Ar/B-1
Ar/B-2
Ar/B-3
Ar/B-4
Ar/B-5
Ar/B-6a
Ar/B-6b
Ar/B-7
Ar/B-9
Ar/B-10
Ar/B-11
Ar/B-1 2
Ar/B-13
Ar/B-14
APPENDIX C
C-l
C-2
C-3
C-4
C-5
Current Station Locations
Current Drogues, Arecibo, Cruise 1
Current Drogues, Barceloneta, Cruise 1
Current Drogues at Arecibo, Cruise 2
Current Drogues at Barceloneta, Cruise 2
Hydrographic Station Locations, Arecibo/
Barceloneta
Hydrographic Station Locations, Arecibo/
Barceloneta
Surface Density, Cruise 1
Density, Arecibo, Cruise 1
Density, Barceloneta, Cruise 1
Density, Arecibo, Cruise 2
Density, Barceloneta, Cruise 2
Water Transparency, Cruise 1
Water Transparency, Cruise 2
San Juan
Surface Temperature, Cruise 1
Surface Temperature, Cruise 2
Temperature at 5 Meters, Cruise 1
Temperature at 30 Meters, Cruise 1
Surface Salinity °/oo, Cruise 1
6.159
6.160
6.161
6.162
6.163
6.164
6.165
6.166
6.167
6.168
6.169
6.170
6.171
6.172
7.32
7.33
7.34
7.35
7.36
XVI
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LIST OF FIGURES (cont.)
C-6
C-7
C-8
C-9
C-10
C-ll
C-12
APPENDIX D
D-l
D-2
D-3
D-4
D-5
D-6
D-7
D-8
APPENDIX E
E-l
E-2
E-3
E-4
E-5
Surface Salinity °/oo, Cruise 2
Salinity °/oo at 56 Meters, Cruise 1
Salinity °/oo at 30 Meters, Cruise 1
Density at 5 Meters, Cruise 1
Density at 30 Meters, Cruise 1
Temperature, Cruise 1
Salinity, Cruise 1
Carolina
Surface Temperature, Cruise 1
Surface Temperature, Cruise 2
Surface Salinity °/oo, Cruise 1
Surface Salinity °/oo, Cruise 2
Temperature, Cruise 1
Temperature, Cruise 2
Salinity °/oo, Cruise 1
Salinity °/oo, Cruise 2
Humacao/Yabucoa
Surface Temperature, Cruise 1
Temperature at 5 Meters, Cruise 1
Surface Temperature, Cruise 2
Surface Salinity, Cruise 1
Salinity at 5 Meters, Cruise 1
7.37
7.38
7.39
7.40
7.41
7.42
7.43
7.67
7.68
7.69
7.70
7.71
7.72
7.73
7.74
7.102
7.103
7.104
7.105
7.106
XVII
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LIST OF FIGURES (cont.)
E-6
E-7
E-8
E-9
E-10
E-ll
APPENDIX F
F-l
F-2
F-3
F-4
F-5
F-6
F-7
F-8
F-9
F-10
F-ll
F-l 2
Salinity at 10 Meters, Cruise 1
Surface Salinity, Cruise 2
Temperature, Yabucoa, Cruise 1
Temperature, Yabucoa, Cruise 2
Salinity, Yabucoa, Cruise 1
Salinity, Yabucoa, Cruise 2
Guayama
Surface Temperature, Cruise 1
Temperature at 5 Meters, Cruise 2
Temperature at 10 Meters, Cruise 1
Surface Temperature, Cruise 2
Surface Salinity °/oo, Cruise 1
Salinity °/oo at 5 Meters, Cruise 1
Salinity °/oo at 10 Meters, Cruise 1
Surface Salinity °/oo, Cruise 2
Density at 5 Meters, Cruise 1
Density at 10 Meters, Cruise 1
Temperature, Salinity, Cruise 1
Temperature, Salinity, Cruise 2
7.107
7.108
7.109
7.110
7.111
7.112
7.129
7.130
7.131
7.132
7.133
7.134
7.135
7.136
7.137
7.138
7.139
7.140
XVIII
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LIST OF FIGURES (cont.)
APPENDIX G
G-l
G-2
G-3
G-4
G-5
G-6
G-7
APPENDIX H
H-l
H-2
H-3
H-4
H-5
H-6
H-7
H-8
APPENDIX I
1-1
1-2
1-3
Ponce
Surface Temperature, Cruise 1
Surface Salinity °/oo, Cruise 1
Surface Salinity °/oo, Cruise 2
Temperature, Cruise 1
Temperature, Cruise 2
Salinity °/oo, Cruise 1
Salinity °/oo, Cruise 2
Guayanilla
Surface Temperature, Cruise 1
Surface Temperature, Cruise 2
Surface Salinity °/oo, Cruise 1
Surface Salinity °/oo, Cruise 2
Temperature, Cruise 1
Temperature, Cruise 2
Salinity °/oo, Cruise 1
Salinity °/oo, Cruise 2
Mayaguez
Surface Temperature, Cruise 1
Surface Temperature, Cruise 2
Surface Salinity °/oo, Cruise 1
7.151
7.152
7.153
7.154
7.155
7.156
7.157
7.173
7.174
7.175
7.176
7.177
7.178
7.179
7.180
7.197
7-198
7-199
XIX
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LIST OF FIGURES (cont.)
1-4
1-5
1-6
1-7
1-8
APPENDIX J
J-l
J-2
J-3
J-4
J-5
J-6
J-7
J-8
APPENDIX K
K-l
K-2
K-3
K-4
Surface Salinity °/oo, Cruise 2
Temperature, Cruise 1
Temperature, Cruise 2
Salinity °/oo, Cruise 1
Salinity °/oo, Cruise 2
Aguadilla
Surface Temperature, Cruise 1
Surface Temperature, Cruise 2
Surface Salinity, Cruise 1
Surface Salinity, Cruise 2
Temperature, Cruise 1
Temperature, Cruise 2
Salinity, Cruise 1
Salinity, Cruise 2
Arecibo/Barceloneta
Surface Temperature, Cruise 1
Surface Temperature, Cruise 2
Surface Salinity °/oo, Cruise 1
Surface Salinity °/oo, Cruise 2
7.200
7.201
7.202
7.203
7.204
7.219
7.220
7.221
7.222
7.223
7.224
7.225
7.226
7.250
7.251
7.252
7.253
XX
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LIST OF FIGURES (cont.)
K-5 Temperature, Arecibo, Cruise 1 7.254
K-6 Temperature, Arecibo, Cruise 2 7.255
K-7 Temperature, Barceloneta, Cruise 1 7.256
K-8 Temperature, Barceloneta, Cruise 2 7.257
K-9 Salinity, Arecibo, Cruise 1 7.258
K-10 Salinity, Arecibo, Cruise 2 7.259
K-ll Salinity, Barceloneta, Cruise 1 7.260
K-12 Salinity, Barceloneta, Cruise 2 7.261
XXI
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SECTION 1
SUMMARY
1.1
-------
SECTION 1
SUMMARY
INTRODUCTION
A comprehensive Water Quality Management Plan for the Commonwealth
of Puerto Rico is being prepared by the Puerto Rico Environmental Quality
Board. This plan is being financed, in part, by Basin Planning Grant
funds from the United States Environmental Protection Agency. One of
the key data bases needed in order to formulate a water quality
management plan is baseline oceanographic data for coastal waters,
especially in areas near existing or anticipated locations of regional
primary treatment facilities. Such information is required to provide a
preliminary basis for evaluating the general feasibility of the marine
disposal of wastewaters emanating from the regional facilities. Further-
more, it was decided to establish an operational on-island oceanographic
study group capable of fulfilling the increasing need for physical and
biological data on the marine environment in order to ensure effective
utilization and/or protection of marine resources. The Environmental
Quality Board contacted the Area of Natural Resources, of the Department
of Public Works (now Department of Natural Resources), to establish
this oceanographic study group and carry out the required studies.
At present, the proposed Plan recommends that the Commonwealth of
Puerto Rico be divided into 13 regional basins. Treatment Facilities
with ocean outfalls are planned at 16 locations. Some of these facilities
will initially provide only primary treatment of wastewater.
1.2
-------
The construction of these regional wastewater treatment facilities
as primary level treatment is considered as a first step. As the Common-
wealth construction program develops, the primary level facilities will
be expanded to secondary treatment capability in accordance with present
Environmental Protection Agency ocean disposal policy.
A key physiographic feature of each of the marine environments in
the above regional basins is the width of the island coastal shelf. In
many areas, such as Humacao/Yabucoa and'fuayama, the coastal shelf has
a width of several miles; however, in the remainder of the areas it is
much narrower.
The probable wastewater treatment scheme to be used for most of the
regional wastewater treatment facilities will include a primary treatment
system coupled with an ocean outfall-diffuser system. The key feature
in the feasibility of such a system is the level of performance achieved
by the outfall-diffuser system; that is, the specifics of design and
operation of a primary treatment/outfall-diffuser system is dependent on
the initial dilution and subsequent attenuation of wastewater characteristics
as the waste is dispersed by prevailing currents. Given this perspective,
the basic approach to the resolution of coastal zone pollution problems
around the island of Puerto Rico involves the assessment of the waste
dilution/dispersion potential of nearshore waters and the determination
of flow to maximize the utilization of this potential.
Based on the goals set for the Oceanographic Project, the immediate
objectives were determined to be:
preliminary characterization of prevailing current patterns
characterization of the extent of vertical stratification
in the receiving waters.
1.3
-------
water quality data (i.e., water transparency, dissolved
oxygen, coliform organisms, etc.)
background information on the coastal shelf
a
coliform organism disappearance rates
DATA ACQUISITION
The Oceanographic Project acquired most of the required data by
conducting three separate survey cruises around Puerto Rico, covering
areas in the vicinity of the regional treatment basins. The dates of
the beginning and end of each of the cruises are:
o
Cruise 1 - April to July 1971
Cruise 2 - August to October 1971
Cruise 3 - December 1971 to February 1972
During Cruise 1 current measurements were made with an Ekman-Merz
current meter at all but two of the sites, where drogues were used.
Drogues were used for current measurements at all sites during Cruise 2.
Salinity, temperature, and water quality measurements were also carried
out during these cruises. Three newly-acquired in-situ recording current
meters were used during Cruise 3 at a selected number of the sites covered
during the preceding two cruises. In addition, coliform disappearance
rate studies were conducted along the west and south coasts of the island
during July 1971 and January 1972.
OVERVIEW OF DATA
Ocean Currents
The most satisfactory current data was obtained during Cruise 3 when
the three in-situ recording current meters were used. A cyclic pattern,
suggesting dominant tidal influences, was observed at all depths at the
following sites: Carolina, Guayama, Ponce, Guayanilla, and Mayaguez.
1.4
-------
Although the current patterns observed at San Juan and Humacao/Yabucoa
do exhibit more-or-less cyclic tendencies, the pattern is not as definite
as that observed at the preceding areas.
Density Structure
Vertical density gradients, computed from temperature and salinity
data obtained at each site, were found to be small.
Water Quality
The lack of a data base against which to evaluate current water
quality levels at each site makes it difficult to interpret the results
obtained. The water quality data which was collected should be of value
in the future when further measurements are made.
Coliform Disappearance Rate Studies
Several studies were conducted in the vicinity of the Mayaguez dis-
charge plume. The results of trace studies show T disappearance rate
90
values of 0.9 to 2.9 hours. Less definite results were obtained from
the disappearance rate study conducted in the dispersed plume of the
Guayama outfall. In this case the decrease in coliform concentration
appears to have been due solely to dilution processes.
CONSIDERATION OF DILUTION POTENTIALS
The data bases on the coastal current patterns and vertical density
gradients developed during the study were used to make estimates of initial
dilution and subsequent dilution potentials. Based on an evaluation of
this data it has been concluded that:
the majority of potential initial dilution values will range
from 50 to 200 for diffusers placed on the island shelf (i.e.,
at depths less than 600 feeti)
1.5
-------
in eight of the eleven study areas, the approach to marine
waste disposal will have to rely heavily on initial dilution
processes. The areas in which wastewater management may
be able to take advantage of the reduction in wastewater
constituents due to dilution processes are: Humacao,
Guayama, and Mayaguez.
1.6
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SECTION 2
INTRODUCTION
2.1
-------
SECTION 2
INTRODUCTION
GENERAL
The Environmental Quality Board (EQB), of the Commonwealth of Puerto
Rico, is responsible for the preparation of a Comprehensive Water Quality
Management Plan (Plan) for Puerto Rico. This effort is being financed
in part by the United States Environmental Protection Agency (EPA through
Basin Planning Grant Contract No. B-002025 as authorized by Section 3 (c)
of the Federal Water Pollution Control Act, as amended.
Information on the basic physical characteristics of the coastal
waters of Puerto Rico was determined by EQB as one of the key data bases
needed to complete the Plan. This information is needed for two reasons:
(1) to provide a preliminary basis for evaluating the general feasibility
of marine disposal of wastewater, and (2) to develop background information
on the local oceanographic conditions around the island.
It was decided to contract the desired oceanographic work out to the
Department of Public Works (DPW) of the Commonwealth of Puerto Rico. The
work was scheduled to begin 7 January 1971, to end 7 March 1972, and to have
a budget of $234,000.
STUDY OBJECTIVES
Basically, the Oceanographic Study Program (Program) had one, major
short-range and two, major long-range objectives to satisfy.
The short-range objective was to obtain the necessary baseline data
required for engineering design studies on the feasibility of marine disposal
of wastewater from Puerto Rico. This objective was accomplished through
measurements and evaluations of ocean current, water stratification,
2.2
-------
nearshore topography, waste discharge volumes and locations, and rates of
coliform disappearance at selected Study Areas. These areas were defined
as the coastal waters in the vicinity of proposed Regional Wastewater Treat-
ment Facilities.
One of the longer-range objectives was to furnish the Commonwealth
and its agencies with a portion of the information base from which to develop
plans for marine water resources management including the protection of
designated beneficial-uses to be sustained along the coastal environments
and for further development of its coastal marine environment. This
objective was sought through the process of acquiring water-quality data in
the specified Study Areas.
The other long-range objective was to initiate the training of Puerto
Rican personnel and the development of on-island, oceanographic capabilities
necessary to assist in the definition and resolution of coastal water
pollution problems. Towards meeting this objective, the EQB and DPW estab-
lished an Oceanographic Project Group (Project) within the DPW's Area of Natural
Resources, and reassigned personnel and employed new personnel to form the
Study Staff. It is planned to maintain this Project as a viable entity (in
the new Department of Natural Resources) and have it actively participate
in the gathering and evaluation of oceanographic information germane to the
goals and needs of Puerto Rico.
2.3
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PROJECT ORANIZATION AND MANAGEMENT
The line positions of EPA, EQB, DPW, Area of Natural Resources, and the
Oceanographic Project are diagramed in the Project Organization Chart (Figure
2-1) . To assist in the conduct and the management of the oceanographic work
program, several staff positions were established. The Project Policy Board
consisting of representatives of those agencies listed in Figure 2-1 was
set-up to determine initially the overall direction for the oceanographic
study. Members of this Board were instrumental in the preparation activities
that resulted in this Ocenographic Study. The other major Board, the Project
Control Board, was set up to review the progress of the work and to reorient
the work program as necessary. The Technical Advisory Committee was established
to review and make recommendations on the technical aspects of the Study. Unlike
the Project Control Board which met at its own or the Executive Director of EQB's
discretion, this Committee met at the discretion of the Oceanographic Project
Director. Finally, the engineering firm of Engineering-Science, Inc. was
retained as a consultant to the Oceanographic Project Director.
ACKNOWLEDGEMENT
Many individuals and organizations participated in and contributed to
the conduct and completion of this study. These efforts as a whole are
gratefully acknowledged. Special appreciation is extended to the members of
the Project Control Board for their participation in the management and report
review process:
2.4
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Dr. E. Pearson (Chairman, July 1971 Co March 1972)
Mr. A. Heres (Chairman, January to June 1971)
Dr. R. Vazquez
Dr. F. Lowman
Dr. W. Gates
Mr. P. Storrs
Also, the informal participation of representatives of EPA, Mr. N. Priede
and Dr. D. Washington, is acknowledged.
Recognition is also extended to the Project staff for their day-to-
day efforts in the filed as well as in the office towards the completion
of this study. Specifically, these individuals are:
Mr. W. Metcalf (Project Director, January to December 1971)
Mr. F. Torres (Project Director, January to March 1972)
Mr. J. Cooper
Mr. K. McCarey
Miss C. M. Cham
Mr. C. Bauer
Mr. A. Lopez
Mr. N. Espar
Mr. W. Perl
Miss. A. Avillan
2.5
-------
Appreciation is also due to staff members of Engineering-Science, Inc.
The participation of the following individuals is acknowledged:
Dr. N. Armstrong
Dr. A. Kemmerer
Dr. G. Beers
Mr. J. Drucker
Mr. T. Smith
Mr. E. Jerome
Mr. M. Fluharty
Certain aspects of the field program were helped immensely by the loan
of oceanographic equipment by Dr. E. Colon of the Institute of Water Resources
Research at the University of Puerto Rico at Mayaguez, Puerto Rico.
Finally, appreciation is extended to the unidentified fisherman who on
more than on occasion provided field help to Project personnel.
2.6
-------
Environmental Protection Agency
Environmental Quality Board
Project Policy Board
Planning Board
Department of Agriculture
Fomento
Department of Public Works
Department, of Health
Water Resources Authority
Aqueduct and Sewer Authority
Public Service Commission
Environmental Quality Board
Environmental Protection Agency
Department of Public Works
Area of Natural Resources
Project Control Board
Environmental Quality Board
Department of Public Works
Puerto Rico Nuclear Center
Consultant
Engineering-Science, Inc.
Technical Advisory Committe Oceanography
Proj ect
Department of Public Works
Aqueduct and Sewer Authority
Environmental Quality Board
Environmental Protection Agency
Engineering-Science, Inc.
Project
Staff
Engineering-Science, Inc,
PROJECT
ORGANIZATION
CHART
FIG 2-4
2.7
PUERTO RICO OCEANOGRAPHIC PROGRAM
-------
SECTION 3
THE OCEANOGRAPHIC PROJECT AND
THE WASTEWATER MANAGEMENT PROGRAM
3.1
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SECTION 3
THE OCEANOGRAPHIC PROJECT AND THE
WASTEWATER MANAGEMENT _PROGRAM
GENERAL
Many segments of the hydrosphere have been and are being used for
the disposal of wastewaters. In the majority of cases, wastewaters are
discharged into inland and coastal waters from shoreline and subsurface
outfall systems. Less commonly, wastewaters are discharged into ground-
waters by means of a variety of infiltration techniques and direct injection
methods. In a very few cases, wastewaters have been disposed of in the
atmosphere by means of evapotranspiration and evaporation methods.
The expectation of society for the desired beneficial uses of receiving
waters at a particular geographic location determines to a large extent
the limitations upon use of such waters as a wastewater disposal system.
A wastewater treatment and outfall system can be viewed as a train of unit
processes intended to reduce the concentration of selected constituents
through conversion, separation, dilution, and dispersion to levels which will
result in achieving environmental parameter levels equal to or less than
the desired parameter levels.
There are a number of unit processes (1,2) designed to bring about
one or more changes in the characteristics of the waste stream. Depending
upon the economic, political, ecologieal, and technical constraints, there
is usually more than one candidate unit process train for meeting the
treatment and disposal objectives of introducing a wastewater into a parti-
cular receiving water. A listing of commonly used treatment process
alternatives is presented in fable 3-1.
3.2
-------
A common example of unit process train alternatives for marine waste
disposal systems occurs in the situation in which the concentration of
coliform organisms in the receiving water is of major concern. The typical
tradeoff situation for the same level of wastewater treatment is:
(1) use of shorter, less expensive outfall in conjunction
with a chlorination system to achieve the receiving water
and littoral zone coliform standard; versus
(2) use of a longer outfall system to deeper waters without
a chlorination system to meet the same objective.
CONTEXT FOR PUERTO RICO
The Commonwealth of Puerto Rico is in the initial stages of upgrading
its wastewater management program on a regional basis. Sanitary and industrial
wastewater treatment facilities on the island are, with few exceptions,
inadequate. Presently, all but one of the 78 urban ceenters in Puerto Rico
have some form of sanitary sewage facilities, however extensive areas are
unsewered. Of the approximately 80 mgd handled by the facilities in the
78 urban centers, only about 13 mgd (15.8 percent) receives secondary
treatment, about 47 mgd (58.7 percent) receives primary treatment, about
7.8 mgd (9.7 percent) receives septic tank and/or Imhoff tank treatment,
and the reamainder (13 mgd, or 15.8 percent) is discharged to the ocean
without any treatment. The seven locations of raw sewage discharge to the
ocean are identified in Figure 3-1, along with the type of treatment provided
at other sanitary facilities on the island. The locations of industrial
waste discharge are also shown in Figure 3-1.
3.3
-------
The projection of wastewater discharges from municipal and industrial
sources for 1980 are 252 and 129 mgd, respectively. By 2020, the wastewater
flows from municipal and industrial sources are projected to be about 648
and 209 mgd, respectively.
A candidate island-wide wastewater management program has been proposed
to deal with existing and impending water pollution problems. Basically,
the plan divides the island of Puerto Rico into 16 Water Quality Management
Regions, as shown in Figure 3-2. Not shown in the figure is the region formed
by the small offshore islands of Vieques and Culebra. These regional areas
a-f-e consistent with the program being developed by the Commonwealth under the
Federal Water Pollution Control Act, Section 3(c) Basin Planning Grant. The
candidate plan of the Commonwealth (3) also identifies the regional basins
as being one of two types, i.e. primary or secondary, as illustrated in Figure 3-
The ten primary regions are scheduled to be provided with primary
treatment systems in conjunction with long ocean outfalls, whereas the six
secondary regions will be provided secondary treatment systems and/or waste-
water re-use reclamation systems. Secondary and tertiary treatment facilities
are planned for the more inland areas of the island, as identified in Figure 3-2.
The feasibility of operating a primary treatment system coupled
with an outfall-diffuser is the level of performance which can be attained
by the outfall-:dif fuser. This, in turn, is dependent upon the initial
dilution and subsequent attenuation of wastewater characteristics achievable
as a result of the physical, chemical, and biological interactions occurring
in the receiving waters at and in the vicinity of the discharge. The lack of
information on the nearshore oceanography prior to the present study was an
outstanding technical gap that would constrain the planning and evaluation of
many of the proposed treatment facilities on the shores of Puerto Rico.
3.4
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Thus the immediate'mission of the Oceanographic Project was to obtain
nearshore oceanographic information, particularly as regards to water density
stratification and current patterns, at the eleven study sites where primary
treatment facilities have been proposed. For the purposes of this etudy
nearshore was defined to mean within the 600 ft. (100 fathom) depth contour,
as shown in Figure 3-3. The data obtained would provide an information base
for use in subsequent preliminary feasibility studies of outfall-diffuser
systems at the selected sites.
3.5
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TABLE 3-1
COMMON UNIT PROCESSES UTILIZED
IN WASTEWATER TREATMENT TRAINS
Principal Purposes of
Unit Process
Unit Process
Grit removal
Removal or grinding of coarse
solids
Odor control
Gross solids-liquid separa-
tion; BOD reduction
Gross removal of soluble BOD
and COD from raw wastewater
Removal of oxidized particu-
lates and biological solids
Decomposition or stabiliza-
tion of organic solids; con-
ditioning of sludge for
dewatering
Improve sludge dewatering
characteristics
Preparing organic or chemical
sludge for disposal or
further treatment
Ultimate sludge disposal
Grit chambers
Bar screens; Consmintstors
Prechlorination; Ozonation
Plain primary settling
Biological treatment
Plain secondary settling
Anaerobic sludge digestion
Anaerobic digestion; Thickening;
gravity, flotation; Elutriation;
Heat treatment; Ash conditioning;
Chemical conditioning; chlorine,
alum, lime, polymers, iron s<s
Dewatering organic or chemical
sludge: air drying, centrifuging,
vacuum filtration (coil septum,
fabric septum, filter press)
Incineration: multiple-hearth,
fluidized bed; Land disposal;
Injection; Recovery and reuse of
chemical sludges
3.6
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TABLE 3-1 (cont.)
COMMON UNIT PROCESSES UTILIZED
IN WASTEWATER TREATMENT TRAINS
Principal Purposes of
Unit Process
Unit Process
Removal of colloidal solids
and turbidity from wastewater
Phosphorus removal
Nitrogen removal
Removal of suspended and
colloidal materials; protection
of granular cafcbon beds or iron
exchange beds from foulimg or
plugging
Removal of dissolved trace
refractory organics-MBAS,
COD, BOD, color, odor, etc.
Disinfection; bacteria and
virus inactivation
Ultimate wastewater disposal
Chemical treatment, sedimentation,
and mixed-media filtration: alum,
lime, polymers, iron salts
Chemical coagulation, flocculation,
and settling: lime, alum, iron
salts
Ammonia stripping
Mixed media filtration; Dual media
filtration
Granular activated carbon adsorption:
upflow packed, upflow expanded,
downflow series beds
Chlorination, Ozonation
Land disposal; Injection; Ponding;
Outfall-diffuser system
3.7
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SABELA
ARECIBO
SAN JUAN
AGUADILLA 4
I
MAYAGUEZ
L E G END
INDUSTRIAL WASTE DISCHARGE
X SANITARY SEWAGE DISCHARGE
1 SEPTIC OR IMHOFF TANK
2 SEPARATE PRIMARY SEDIMENTATION
AND DIGESTION
3 SECONDARY TREATMENT
4 RAW SEWAGE
GUAYAMA'
'ARROYO
FIG 3-1
LOCATIONS OF EXISTING SANITARY AND INDUSTRIAL
TREATMENT FACILITIES IN PUERTO RICO (PROM REFERENCE 10)
-------
SAN JUAN
A6UAOA
VEW BAJA
8ARCELONETA
MANATI
LEGEND
FtG 3-2
WAIN FEATURES OF THE PROPOSED REGIONAL
WASTEWATER MANAGEMENT PROGRAM
O REGIONAL TREATMENT PLANT
I PRIMARY TREATMENT PLANT
2 SECONDARY TREATMENT PLANT
3 TERTIARY TREATMENT PLANT
& LOCAL SECONDARY TREATMENT PLANT
REGIONAL BASIN TYPE:
i I PRIMARY
SECONDARY
-------
0 C E A N 0
A TLANTICO
Ul
a
_i
o
600ft WATER
DEPTH
CONTOUR
(ISLAND SHELF)
TRUE
NORTH
0 10
J 1_
20 3O Km
FI6 3-3
EXTENT OF COASTAL SHELF AROUND PUERTO RICO
-------
SECTION 4
GENERAL DESCRIPTION OF STUDY AREAS
4.1
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SECTION _4
GENERAL DESCRIPTION OF STUDY AREAS
GENERAL
The Commonwealth of Puerto Rico consists of a main island and several
smaller islands located in the Caribbean, approximately 1,000 miles southeast
of Miami, Florida (1). The nearest land mass of significant size is the
island of Hispaniola situated approximately eighty miles to the west (1).
Puerto Rico is shown in relation to other land features within the Northern
and Western Hemispheres in Figure 4-1 (1).
Puerto Rico is roughly 110 miles from east to west and 35 miles from
north to south, and lies in the region of the northeast trade winds. The
mean tidal range is 1.1 feet, the neap tides being 0.6 feet and the spring
tides being 1.4 feet (2).
In spite of its small size and the relative constancy of the trade wind
belt climate, the marine environment is by no means without contrasts from
place to place. Each of the four sides of the more or less rectangular island
has its own distinctive climatic and environmental features. The North Coast
is washed by the tropical North Atlantic Ocean and the South Coast by the
Caribbean Sea. The passages between Puerto Rico and St. Thomas, Virgin Islands,
to the east, and Hispaniola to the west, are broad and relatively shallow.
Extreme variations in rainfall have been recorded as Puerto Rico lies
in the Caribbean hurricane belt and, at intervals of from 4 to 7 years, lies
within or immediately adjacent to a hurricane path (1). Distribution of rain-
fall is shown in Figure 4-2 (1).
The rainfall is primarily orographic in nature. The air mass of the
trade winds, which becomes moisture laden during its passage across the ocean,
4.2
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releases the moisture as the air is forced upward by the mountains of
Puerto Rico. Most of the moisture is released in the northern and eastern
slopes, which also get most of the watershed. The rain shadow effect of the
Cordillera Central and Sierra de Luquillo is shown in the South Coast with
its maximum effect in the southwest where annual rainfall averages 40 inches
a year. Tropical storms and hurricanes, while infrequently hitting the
island, present a potential threat of high winds and torrential rains from
June through October.
As a rapidly developing industrial community with a very rapid pop-
ulation expansion, and a rugged terrain which tends to concentrate the pop-
ulation in relatively small densely settled areas, Puerto Rico is subjecting
its environment to increasingly severe stress in the matter of waste disposal
and consequences. As of April 1970, the population of Puerto Rico was
2,689,032 (3). This figure represents an increase of 340,388, or 14.5%, from
the 2,349,544 inhabitants enumerated in the 1960 census (3). It was also
estimated that the population of Puerto Rico will reach 5 million in the year
2020, an increase of 2.3 million over 1970. Table 6-1 presents population
projections for several planning regions established for the purpose of the
water pollution abatement basin plan (3).
COASTAL AREA DIFFERENCES
North Coast
The North Coast of Puerto Rico is marked by a relatively narrow con-
tinental shelf, rarely more than 2 or 3 miles wide before sloping very steeply
down into one of the deeper basins of the North Atlantic Ocean. Offshore,
the sea and swell generated by the very steady northeast trade winds over
several thousand miles of open ocean are in many places obstructed from pounding
4.3
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directly on the shore by offlying shoals of beach rock formation. Nevertheless,
the water as it reaches the shore is usually fairly turbulent.
The winds are practically always from the easterly quadrant, with north-
east winds predominating. The mean annual velocity is 8.5 knots at San Juan
Airport, which probably is typical for the North Coast as a whole. July is the
windiest month, with average peak speeds of over 15 knots, and October and
November have the lightest winds. Figure 4-3 illustrates the effects of on-
shore and offshore breezes upon the trade winds at four coastal sites (4).
Although the tidal range has a mean value of only 1.1 ft., and 1.3 ft.
during spring tides (2), there are pronounced sfflai-diurnal tidal components
to the currents off the North Coast. In the open Atlantic offshore from
Puerto Rico, the North Equatorial Current has a generally constant flow to
the west with an average speed varying from about 0.3 knot in the winter to
0.7 knot in the summer, according to the Pilot Charts, However, it may be
that the passage of major atmospheric pressure systems in the open ocean,
combined with the tidal components and the local geographical effects of the
capes and inlets, is responsible for complicating the current picture. At
any rate, the North Coast currents flow most of the time to the west rather
than to the east in most places.
East Coast
The East Coast of Puerto Rico is marked by a broad shallow shelf which
reaches out to the islands to the east. The passage between Puerto Rico and
Isla Vieques, for example, is about 7 miles wide at its narrowest point and
only 16 meters deep at its deepest point. Islands and shallow waters protect
the coast in some degree from open-ocean waves. The trade winds are extremely
steady from the east in this area with an average velocity ranging from just
under 6 knots in October to 9 knots in July.
4.4
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In Pasaje de Vieques, the shallow passage between Puerto Rico and
Vieques Island, the tidal component predominates in the current picture. Daily
current predictions are listed in the Tidal Current Tables (2). It should
be mentioned that in the shallow bays and inlets lining the East Coast, the
times of current reversal and directions of flow may vary markedly from those
listed for the middle of the channel in the current tables.
Tidal currents are further complicated by the fact that near the south-
eastern corner of Puerto Rico, the tidal pattern is affected by the semi-
diurnal tide that predominates along the North Coast and the diurnal mixed
tide commonly found in the Caribbean Sea.
South Coast
Being partially in the shadow of the main bulk of the island as far as
the trade winds are concerned, the South Coast of Puerto Rico has a wind
pattern distinctly different from the patterns found along the North and East
Coasts of the island. As a broad generalization, it can be said that the
wind is generally from the eastern quadrant with a strong onshore (SE) component
developing during the heat of the day and a strong offshore (NE) component
predominating during the night and cooler parts of the day (5). However, this
is an over-simplification, and the pattern frequently is quite complex. The
windiest month is March, with an average of 7.7 knots from the east-southeast.
The precipitation in the eastern quarter of the South Coast is similar
to that found along the North Coast. The average is 60-80 inches a year,
falling away to about half of that towards the west (see Figure 4-2).
The continental shelf along the South Coast is over 5 miles wide in
most places before dipping steeply into the Venezuelan Basin of the Caribbean
Sea. Small coral and mangrove islands protect the South Coast at many places.
The average tidal range is about 1.1 foot and the pattern is complex.
4.5
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Basically, this is a region of diurnal tides, but during part of the lunar
month a distinct semidiurnal perturbation is superimposed on the diurnal
base (2).
A further complicating factor is that the daily predictions for the
South Coast tides are based on the tidal cycle at Galveston, Texas, and
at least part of the time the relationship between the two areas is rather
casual.
West Coast
The West Coast of Puerto Rico is in the shadow of the island as far
as the trade winds are concerced, which brings about a pronounced modification
of the wind pattern. At Mayaguez, on the western end of the island, the effect
of the land and sea breeze acts in almost opposite directions and lessens the
strength of the trade winds to such an extent that it frequently becomes
dominant and a westerly wind is observed (5).
Along the southern half of the West Coast the 100 fathom contour extends
westward for 10 to 15 miles, while it is much closer, typically about 2 miles
offshore, along the northern half of this coast. Depths of 300 to 500 fathoms
prevail across Mona Passage to Hispaniola, which is considerably less than
typical off-shore depths found along the North and South Coasts, while being
much deeper than the waters in the vicinity of Vieques Passage off the East
Coast.
The tides of the West Coast are of a semidiurnal nature. According to
the Pilot Chart, there is a pronounced flow of water from the Caribbean Sea
to the Atlantic Ocean during the winter months, and from the Atlantic Ocean
to the Caribbean Sea during the summer. This can be expected to make a
complicated seasonal shift in the pattern of the currents along the West Coast
of Puerto Rico.
4.6
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P A C I F I C
OCEAN
A T L A N T I C
NORTH
A M E R I C A
OCEAN
». CUBA
HISPANIOLA
*d ^PUERTO RICO
a* ^~> o
CARIBBEAN:
SEA
SOUTH
AM ERICA
FIG 4 1
COMMONWEALTH OF
PUERTO RICO VICINITY MAP
-------
SAN JUAN
°~~\ \
NOTE: CONTOURS SHOW INTENSITY
OF RAINFALL IN INCHES
PER YEAR
FIG 4-2
DISTRIBUTION OF RAINFALL IN PUERTO RICO
-------
FIG 4-3
ANNUAL FREQUENCY OF WIND DIRECTION
AT FOUR COASTAL STATIONS JUNE 1971
THE RECORD PERIODS FOR THE
STATIONS DO NOT COINCIDE
THROUGHOUT
30MI
-------
TABLE 4-1
HISTORIC AND PROJECTED POPULATION
OF PUERTO RICO 1960-2020
1960
1970
1980
1990
2000
2020
Primary Regions:
San Juan
Ponce
Barceloneta
Guayama
Aguadilla
Yabucoa
Arecibo
Gu ay an ilia
Carolina
Subtotal
Secondary Regions
Lajas
Cateuy
Dorado
Santa Isabel
Fajardo
Maunabo
Vieques
Culebra
Subtotal
TOTAL
608,503
191,868
135,439
87,232
163,999
97,405
144,619
80,830
252,719
1,901,021
69,843
79,974
203,536
40,624
35,978
10,785
7,210
573
448,523
2,349,544
748,412
211,166
141,101
88,887
168,207
101,512
140,774
83,943
379,908
2,210,480
69,712
81,711
223,261
42,202
43,206
10,817
7,817
726
479,452
2,689,932
1,035,460
297,045
152,916
106,433
191,369
109,189
154,669
90,789
471,817
2,781,010
75,287
85,627
256,553
48,684
39,682
10,875
6,241
408
523,357
3,304,367
1,200,676
326,787
156,629
110,169
197,427
110,936
154,192
92,495
550,173
3,075,422
75,822
858755
269,678
50,351
39,408
10,740
5,846
358
537,958
3,613,380
1,401,777
359,661
160,521
114,119
203,775
112,801
153,787
94,257
647,648
3,429,131
76,374
85,904
283,646
52,090
39,142
10S606
5,476
314
553,552
3,982,683
1,952,907
436,228
168,881
122,688
217,423
116,861
153,199
97,947
923,419
4,380,745
77,537
86,271
314,451
55,793
38,634
10,345
4,804
242
588,077
4,968,822
-------
SECTION 5
DATA ACQUISITION
5.1
-------
SECTION 5
DATA ACQUISITION
DATA REQUIREMENTS
The following specification of data requirements was given high
priority in the Oceanographic Project:
' characterization of coastal current patterns in
the vicinity of the eleven planned Primary
Treatment Facilities
characterization of vertical density stratifi-
cation patterns at the eleven sites
To the extent possible, it was also desired to obtain data concerning
the following:
*
water transparency
dissolved oxygen
coliform organisms
BOD
silica
phosphate
pH
FIELD PROGRAM
Initially, four cruises around Che island, roughly corresponding
to the four cliraatological seasons, were planned. It was intended that
each of the sites be visited once during each cruise. Due to delivery
delays and other difficulties in procurement of equipment, difficulties
in recruiting personnel with the required skills, problems a^dociated
with obtaining, equipping, and maintaining a suitable vessel, equipment
failures, and delays caused by bad weather, three cruises were actually
5.2
-------
carried out. The third cruise was interrupted before its completion.
Except for one Ekman-Merz current meter and a 23 ft. sport fishing boat
unsuited to the task, there was very little occanographic equipment
available as the study began in early 1971. Only during the last few
months of field activity did equipment resources approximate what was
needed at the start of the study.
During Cruises 1 and 2 the sampling design at each site was as
follows:
five station transects were laid out normal to the
general trend of the coastline
the middle of the five transects at each study area
was aligned along what was considered to be the most
probable outfall-diffuser alignment
hydrographic stations (locations where a string of
Nansen bottles are lowered for temperature and
salinity measurements) were spaced roughly at half
mile intervals along each transect starting as close
to the shoreline or surf zone as feasible and extending
offshore for a distance of either three miles or to the
100 fathom isobath, whichever came first
a single current station (current meter location as
well as drogue release point) was positioned at each
study area on the middle transect where the water depth
was about five fathoms
The general features of this design are shown schematically in Figure
5-1. Concurrent with the execution of the above program, water-quality
measurements were carried out at all sites.
5.3
-------
During Cruise 3 newly acquired in-situ recording current meters were
used at six of the eleven sites. One instrument was placed 6 to 10 meters
below the surface and another about 15 meters above the bottom at approxi-
mately the same location in water between 130 and 150 feet1(or 40 and 46
meters) deep. A third instrument was placed 6 to 10 meters below the surface
at a point roughly mid-way between the other instruments and the shoreline,
in water about 50 feet (15 meters) deep. It was necessary to modify this
scheme at certain locations, as explained in Appendix A.
ON-STATION PROCEDURES
Water depth:
A small portable battery-operated recording echo sounder (Foruno
FG-11 Mark-3) was used to obtain the depth of water at each station.
Early in the development of the work plan it was suggested that a
continuous bathymetric record be made of each transect. During the
course of running these transects very frequent stops, starts, changes
in speed and direction, and prolonged periods of drifting made it quite
impractical to try to reconstruct any reasonable bathymetry without
increasing the time spent at each station beyond the time which had been
alloted. Thus in general the echo sounder was used only on the approaches
to stations and at the stations. Soundings were read from the scale in
fathoms and converted to meters.
Water transparency:
A Seechi disc was used for measuring water transparency. This is a
white disc 30 em in diameter weighted with a lead sinker on the lower
side. The disc was lowered into the water until it was no longer visible
from above the water surface, at which point a reading of the depth of
5.4
-------
the disc was taken. This reading provides an index of the relative clarity
of the water. Secchi disc readings are subject to side effects dependent
upon the angle of the sun, cloud cover, and roughness of the sea surface,
hut in general the results obtained when the sun is well above the horizon
are consistent.
Current measurements:
One tidal cycle is the minimum time period desireable for current
measurements, but in practice this was not always feasible with the
Ekman-Merz current meter or with the drogues which were used during
Cruises 1 and 2. The usual procedure involved putting to sea at dawn,
but in many cases one to three hours of travel time was required to reach
the site. Therefore, current measurements during these two cruises
typically covered periods of the order of 8 to 10 hours.
During Cruise 1 an Ekman-Merz current meter on loan from the Aqueduct
and Sewer Authority was used at all but the last two sites. The practice
with this meter was to anchor at roughly the place where the outfall pipe
would probably terminate. In shallow areas regular observations of 5 to
15 minutes duration were made in sequence at about 5 meters below the
surface and about 5 meters above the bottom. In deeper areas observations
were also made at mid-depth.
When a current meter is used from an anchored boat the movement of
the boat at the end of the anchor line affects the readings in an indeter-
minate manner. Largely for this reason it was decided to use drogues
instead of the Ekman-Merz meter, and steps were simultaneously taken to
obtain several internally recording meters. Drogues were used at the
last two sites during Cruise 1, and at all sites during Cruise 2. Three
drogues were generally released at a time at three different depths.
After two or three hours, another set was put in, and then a third, all
5.5
-------
starting at the same location. The position of each drogue was fixed
at intervals of one or two hours. Fixes were obtained by using a
sextant to measure two horizontal angles between three landmarks. The
position was then plotted on the chart with a three-arm protcactor-
During Cruise 2 an internally recording current meter was borrowed
from the Water Resources Research Institute, University of Puerto Rico,
Mayaguez. It was moored somewhat above mid-depth at most of the sites,
at the starting point for drograe observations,, As in the case of
positioning of the Ekman-Merz meter during Cruise 1, this location was
in the vicinity of the probable termination of an outfall pipe. The meter
was supported by a sub-surface float. It was left in position during
the drogue operations and then recovered. A malfunction was discovered
in this instrument at Ponce, and attempts to correct this were not
successful. The data obtained with this instrument during Cruise 2 has
therefore not been included in this report.
During Cruise 3 three newly acquired in-situ internally recording
current meters (Hydro Products, Model 502) were used. These were moored
to the bottom with 100 to 150 pound scrap iron weights, and supported by
sub-surface flotation. A corrodable link rigged to a small pop-up
marker float was used with each instrument in order to discourage theft
or vandalism. Positioning of these instruments has already been described.
These meters were left in place at each site for periods of up to around
140 hours.
Water temperature:
The water temeperature was measured by deep sea reversing thermometers
used in Nansen Bottles. Temperatures were read to the nearest hundredth
of a degree centigrade immediately at each station. Later, in the
5.6
-------
laboratory ashore, the various routine thermometric corrections were applied.
These rarely changed the field reading by as much as a tenth of a degree.
Under normal sea conditions, experienced observers can obtain sea water
temperatures accurate within two hundredths of a degree.
pH:
A self-contained battery operated pH meter was not obtained until
near the end of the first cruise. Once in fine field, it was found that the
instrument would not function properly aboard the rolling vessel. The use
of the meter was discontinued early during Cruise.2.
Meteorological observations:
Only very simple meteorological observations were made. Wind speeds
were determined either from a hand-held anemometer reading in knots or else
estimated from the effect on the sea surface according to the Beaufort scale.
Water sampling:
At each hydrographic station, teflon lined Nansen bottles were used
to obtain water samples. In shallow water, the bottles were placed on the
steel hydrographic cable no closer than five meters apart. The deepest
bottle was about 3 meters above the weight on the end of the cable. At
some stations the weight was actually bumping the bottom with the rolling
of the vessel. Five Nansen bottles were used where the depth of water
permitted, and in the deeper water, the bottles were spaced further apart
to obtain suitable sampling intervals. The top bottle was Always just
below the surface, and if a mixed layer was present above a thermocline
or halocline, the other bottles were placed in positions to delineate these
features as well as could be estimated at the time.
5.7
-------
The Nansen bottles hold about 1.3 liters of water which was trans-
ferred to various styles and sizes of glass and plastic bottles depending
on what analysis was being made. For example, the salinity samples
were stored in well-rinsed glass bottles of about 100 ml with plastic
cones in the caps to prevent evaporation.
Dissolved oxygen samples were collected in 125 ml dark glass bottles
with ground glass stoppers. These bottles were filled with a rubber
filling tube to prevent air bubbles from entering 1 The chemical reagents
to "fix" the oxygen were then added.
The samples for biological oxygen demand were collected in special
"BOD" bottles and set aside for later incubation and analysis.
Coliform samples were also drawn from the Nansen bottles. The method
by which the coliform analyses were made was changed in the course of
the program as mentioned below.
ANALYTICAL PROCEDURES
Dissolved oxygen, biochemical oxygen demand, and coliform organism
determinations were conducted in accordance with Reference 5.1 Except
for the coliform determinations on water samples collected at Mayaguez
and Aguadilla on the first cruise which employed the multiple test
fermentation technique, all coliform analyses were made using the membrane
filter technique.
Phosphate (reactive) and silicate determinations were conducted in
accordance with Reference 5.2.
5.8
-------
X
200 METER
. CONTOUR
x
1/2 MOe
INTERVAL
'-0
TRANSECT
HYDROGRAPHIC
STATION
FIG 5-1
SCHEMATIC PRESENTATION OF
SAMPLING DESIGN
D CURRENT
STATION
MILE
TT/'/'
LOCATION OF PROPOSED
REGIONAL TREATMENT
FACILITY
SHORE
-------
SECTION 6
CHARACTERIZATION OF THE NEARSHORE
PHYSICAL OCEANOGRAPHIC FEATURES AT THE
ELEVEN STUDY AREAS
6.1
-------
SECTION 6
CHARACTERIZATION OF THE NEARSHORE
PHYSICAL OCEANOGRAPHIC FEATURES
AT THE ELEVEN STUDY AREAS
INTRODUCTION
The ocean current, water temperature and salinity (density),
water quality, and special coliform organism disappearance rate data
are presented and considered in this section of the report. These
considerations are presented by study area and the data bases are de-
fined in the stated order. The study areas are considered In the follow-
ing sequence:
San Juan
Carolina
Humacao
Yabucoa
Guayama
Ponce
Guayanilla
Mayaguez
Aguadilla
Arecibo
Barceloneta
6.2
-------
San Juan Site
Description of Study Area
The San Juan Metropolitan Area is composed of the six municipalities
of San Juan, Bayamon, Catairo, Guaynabo, Trujillo Alto and Carolina. The
Metropolitan Area is located on the North Coast of Puerto Rico and surrounds
the city of San Juan. San Juan, capital of the Island of the Commonwealth
of Puerto Rico, is located at 18° 28'M latitude and G6°07'W longitude. The
mountainous terrain to the south of the metropolitan area is steeply sloped.
To the north the land falls away to become a flat coastal plain. Within the
plain there are numerous bays, lakes, and mangrove swamps (1). The area is
drained by R.IO Bayamon, Rio Piedras and Rio Grande de Loiza. Of these, Rio
Bayamon and Rio Piedras discharge into San Juan Bay.
The San Juan Metropolitan Sanitary District contains 115 square miles
of which approximately 80 square miles are served presently by sewage
facilities (1). Collection systems bring sewage to the main Puerto Nuevo
treatment plant and 13 smaller treatment plants. The Puerto Nuevo plant
provides primary treatment for an average flow of 46 HGD for 1971, which is
its maximum capacity. Plans for expansion of the plant to 60 MGD are in
progress. Plant effluent is discharged into San Juan Bay.
Ilydrodynamic Data
Current data in the vicinity of San Juan Bay was not available prior to
this study. Tidal Current Tables (2, 3) indicate that currents for Bahia
de San Juan are too weak and variable to be predicted. Turbid water plumes
provide an effective tracer on the surface current flow (4). The path
of the turbid waters reaching Bahia de San Juan shows a complex pattern on
6.3
-------
the surface circulation. The plume shows a prevailing westward flow.
However, on occasion the plume veers to the east and a tongue of turbid
xjater can be observed reaching the hotel sector of El Condado.
The currents off San Juan were studied during the three cruises. The
station locations for each cruise are given in Figure SJ-1.
An Ekrnan-llerz current meter was used during Cruise 1. Results are
given in Figure SJ-2. Winds from the F.NE prevailed. A shear in the water
column was evident during the morning hours, and a shift towards the east
occurred around the time of high tide at 1132, as can be seen in Figure SJ-2,
Drogue tracking was used during Cruise 2. Results are given in
Figure SJ-3. On this occasion a strong westward component was found in
surface x^aters and a weaker shoreward flow, with an eastward or westward
component, was found in deeper layers.
A Hydro Products Model 502 in-situ recording current meter was anchored
during Cruise 3 about 600 yards off Isla de Cabras. The x^ater depth was
13 meters, and the depth of the sensor x^as ten meters. This was the first
current measurement carried out with the recently acquired recording meters.
One meter xras anchored, with the intention of retrieving it the next day.
However, a winter storm developed shortly after the meter was released and,
as a consequence, the meter was left in place for a period of five days.
The data obtained from the meter represents a current pattern under
different meteorological conditions from those of the first cruise since
strong v/inds and sx^ells prevailed from the second day the meter was set
(see Appendix C). Higher velocities were recorded during the stormy
weather period (velocities greater than 0.6 knot). This, however, does
6.4
-------
not necessarily represent the real speed values as the high seas might
have some wave-induced motion at the depth of the sensor (10m), creating
a higher speed resultant. Sharp current direction shifts to E or SE are
evident in Figure SJ-A. These fall at periods close to high tide, and
prevail up to the low tide periods when the current veers to W or SW
again. 'Figure SJ-5 shows net flow current vectors with lengths proportional
to the amount of flow in each of eight direction sectors corresponding
to the cardinal and inter-cardinal points. The flow vectors shown for each
octant, together with their net resultant, were computed from data obtained
during 85.3 hours of continuous observation. As can be seen from the
figure, current flow was in the direction of the SW octant for almost 43
percent of the total time of observation, with a relatively high average
speed of 0.6 knot. The average speeds given in this figure refer
specifically to the corresponding directions, and the average speed shown
for the resultant is the net average in this direction. The method followed
for this analysis is described more fully in Appendix B.
The current data acquired at San Juan during the three cruises indicated
a fairly variable pattern in which there seems to be some tidal influence.
In all the current observations at San Juan, no northward currents were seen,
while strong onshore flows often prevailed. Tabular data of the current
studies is given in Appendix C.
Hydrographic Data
Hydrographic station locations are shown in Figure SJ-6. Since the den-
sity structure as a function of salinity and temperature is the parameter used
6.5
-------
in the engineering design aspect, only this parameter will be discussed
here. The data on temperature and salinity is given in Appendix C.
The surface density (sigma-t) pattern for Cruises 1 and 2 is shown
in Figures SJ-7 and SJ-8. Isopycnal lines were not connected for Cruise
2 (Figure SJ-7) since the data obtained was from two separate dates; in-
stead surface values for each station were recorded. In both cases, de-
creasing density values x^ere observed as the bay was approached. The
gradient is steeper in the east-west direction, suggesting a generally
westward flow of the less dense bay water. The surface sigma-t values
ranged from 22.08 sigma-t units at Station 16 to 24.15 at Station 2 during
Cruise 1, and from 22.89 at Station 9 to 23.11 at Station 8. The average
surface sigma-t value for Cruise 1 (in April) was 23.21, and for Cruise 2
(in August) was 22.98. This suggests a seasonal variation. A more reliable
basis for determining seasonal variations was obtained from the average
value at 10m depth, where local short-term atmospheric conditions show no
immediate effect. The values obtained were 24.04 sigma-t units for Cruise
1 and 23.01 for Cruise 2.
Density profiles for Cruises 1 and 2 are shown in Figure SJ-9. These
represent the central section for each cruise. A strong density gradient
was found during both cruises between surface and 160m. Cruise 1 showed a
difference of 2.33 sigma-t units and Cruise 2, 2.51 sigma-t units. However,
since the gradient is steeper in the upper levels the difference between
surface and 60 meters was about 2 sigma-t units. This is the section which
cuts directly through the plume of warm, less saline water emerging from
San Juan Bay. The area in this central section has the greatest density con-
trast between the surface and the maximum practical depth for an outfall
6.6
-------
(see Appendix C). Thus, with suitable mixing of the waste material, this is
the area where waste-water discharge is least likely to reappear at the
surface.
Water Quality
Water quality data for the San Juan site for Cruises 1 and 2 are given
in Appendix C. Secchi disc readings can be seen to follow the shoreline,
with no major tongues of turbidity during either cruise (Figures SJ-10 and
SJ-11). The Silica and phosphate levels were low on both cruises. Silica
values ranged from 0.02 to .50 mg/1 (1.00 mg at/1 to 8.00 mg at/1).
Phosphate levels ranged from 0.000 to 0.12 mg/1 (1.26 mg at/1). North
Atlantic values for Silicate as given by Rhodes (5) range from 0.5 to 35 mg
at/1, and nitrate from 0.25 to 1.0 mg at/1 in equatorial Atlantic oceanic
waters.
On the second cruise DO, BOD and coliform index were also obtained. DO
values ranged from 3.92 to 6.65 mg/1, and Coliform level from 0.0 to 400
:tF/1001. BOD values ranged fron 0.31 to 0.50 mg/1.
6.7
-------
-- 100 FM
CURRENT METER
CRUISE 3
CURRENT METER
CRUISE I
DROGUES CRUISE 2
1C Ffv,
CANO DE MARTIN PENA
FIG SJ-I
CURRENT STATION LOCATIONS
SAN JUAN SITE
2 Miles
-------
SHALLOW
5M
/
HIGH TIDE 7
5M: /4M
0=^.--o
MID - DEPTH
IBM.
DEEP
40M.
TIME 07 08 09 10 II 12 13 14 15
SCALE
' 2°
CM /SEC
25 50
FIG SJ-2
CURRENT VECTORS
SAN JUAN SITE
CRUISE I APRIL 20, 1971
WATER DEPTH 42 M
HIGH TIDE 1142
WIND FROM E N E
RISING TIDE
FALLING TIDE
'.. 9
-------
65°l 10'
1249
-01 408
0922
0814
1546
1358
PTA. SALINAS
645
1615
1634
1457
ISLA DE CABRAS
FIG. SJ-3
CURRENT DROGUES
SAN JUAN
CRUI SE 2
AUGUST I I 1971
SERIES 1-2-3
4+ I SURFACE
# I I 10 METERS
#21 25METERS
NOTE
THE ORIGIN OF ALL SERIES SHOWN HERE WAS
ACTUALLY AT THE SAME POINT, AS INDICATED
BY THE WAVY ARROW, AND DROGUE TRACKS
ARE DISPLACED ACCORDINGLY.
OD
B A H I A
DE
SAN JUAN
_l_8^
27-51
-------
/V-x
/ ~\
,"v-\ /N
\
\
\
\
TME 2OOO 0000 O4OO OVOO IZOD 1900 ZOOO OOOO 0400 0*00 1200 I«OO 2000 OOOO 04 OO 0«OO 1200 tflOO ZOOQ OOOO 04OO O»OO
D*TE «/B T/tE
Flfl »J-4
CURDEMT VELOCITY
cftuiic * «-«) oecenacfl IVTI
-------
SENSOR AT 10 M
BOTTOM DEPTH I3M
TOTAL TIME 85-3 HOURS
V=O-54
10.0 %T
V= 0-50
10.5 % T
V = O- 60
42-8 %T
SJ-5
NET FLOW CURRENT VECTORS
CRUISE 3
SAN JUAN
AVERAGE SPEED (V) IN Kn
AND PERCENT OF TOTAL
TIME SHOWN FOR EACH OCTANT
-------
24 *
17*
NAUT MILE
23*
25 *
PTA.
SALINAS
*
18*
IS*
21*
2C*
.22*
*H,
6*
12*
13*
14*
15*
16*
ISLA
DE CAGRAS
7*
S*
9*
1C*
5*
3*
2*
1*
BAHIA OE SAN JUAN
Figure SJ-6a
HYDROGRAPHIC STATION LOCATIONS
SAN JUAN
CRUISE 1 14-20 APRIL 1971
-------
5X
3X
2X
IX
PTA. ...
SALINAS .
11X
17X
6X
10X
16X
12X
7X
9X
15X
13X
8X
ISLA
DE CABRAS .
BAHIA DE SAN JUAN
NAUT MILE
Figure SJ-6b
HYDROGRAPHIC STATION LOCATIONS
SAN JUAN
CRUISE 2 12-23 AUGUST 1971
-------
FIG SJ- 7
SURFACE DENSITY
AT SAN JUAN SITE
CRUISE 1 14-22 APRIL 1971
0
L
2 Miles
SCALE
-------
12 AUG
22.98
22.99
I 23 AUG j 12 AUG
'
23 AUG
23.04
0
L
FIG SJ-3
SURFACE DENSITY
AT SAN JUAN SITE
CRUISE 2 12-23 AUGUST 1971
-------
Depth M
S u rface G t 23. 17
100 -I
120
140 -\
160 -I
CRUISE I
19 April 1971
I Mile
SCALE
II
22.99
23.5
24.0.
24.5
25'0
25.5 -
12
22.97
13
22.94
CRUISE 2
23 AUGUST 1971
A
FIG SJ-9
DENSITY
SAN JUAM SITE
CENTRAL SECTION
-------
BAHIA OE SAN JUAN
00
FIG SJ-IO
WATER TRANSPARENCY
SAN JUAN SITE
SECCHI DISC READJNGS IN METERS
CRUISE I 14,22 JUNE 1971
NAUT MILES
-------
12 AUG
13-
23 AU<3 I 2 AUG
23 AUG
18-
13 .
23-
PTA- SALINAS
13.
13.5
9.
FIG SJ-
WATER TRANSPARENCY
SAN JUAN SITE
SECCHI DISC- READINGS IN METERS
CRUISE 2 12,23 AUGUST 1971
NAUT Ml
-------
CAROLINA
Description of Study Area
Carolina is located on the north coast of Puerto Rico near the
eastern end of the Island, approximately 15 miles east of San Juan. The
Rio Grande de Loiza discharges into the Atlantic Ocean about 5 miles
east of Carolina after the following major tributaries join it: Rio
Turabo, Uio Caguitas, Rio Bairoa, Rio Gurabo, Rio Canas and Rio Canovanas.
The Loiza watershed comprises an area of 207 square miles (1). A con-
siderable area of this watershed is marshland and a number of drainage canals
flow into the river bed. The larger canals are the Gallardo, San Irido,
and Marbarto. The water of the Rio Loiza in this three-mile-wide coastal
band of marshlands is deeply colored due to "humic acid", a product of
decaying vegetable matter.
Three towns are located within the Rio Loiza watershed: Trujillo
Alto, Carolina, and Canovanas. The waters from this river and its tribu-
taries converge in Lake Carraizo, just south of Trujillo Alto. On its
course to the Carraizo Dam," the river receives wastes from a sugar mill
at Juncos, five domestic sewage treatment plants, two slaughterhouses, and
a hide tannery (1). North of the site, four rock quarries and gravel pits
situated close to or on the river bank contribute suspended solids and
turbidity to the water (2).
Hydrodynamic Data
Current measurements were obtained in three surveys for Carolina. The
station locations for each survey are shown in Figure C-l. The results of
6.20
-------
the first cruise are given in Figure C-2. One of the interesting
characteristics of Carolina currents as observed from an analysis of the
data is the prevailing easterly flow, which contrasts with the general
belief in the existence of a westerly flow pattern along the north and
south coasts of Puerto Rico. A prevailing easterly flow was observed
during Cruise 1, with a shift in direction for surface water during time of
high tide. Average speed was 0.6 knot for the surface water, 0.7 knot for
mid-depth, and 0.7 knot for deep water (see Appendix D).
Figure C-3 shows the results of drifting drogues for Cruise 2. An
eastward path prevailed throughout the entire period of observation. Surface
speed values ranged from about 0.2 to over 0.8 knot, with an average value
of 0.45 knot. Mid-depth values ranged from 0.5 to over 0.8 knot, with an
average speed of 0.73 knot. The average speed in deep water x^as 0.58 knot.
The significant difference between surface average speed and speed of deeper
waters may reflect the wind influence on the surface, as wind was blowing
from the east with speeds ranging from 10 to 19 knots (see Appendix D).
The limitations of the first txro cruises relate to the short period of
observation where less than a tidal cycle is covered each time and no
relationship with lunar cycle could be established. In the third cruise
in-situ current meters were used as described in Section 5. The original
intention was to set the meters for a 48-hour observation period, but due
to a combination of factors, namely a failure of the corrodable links and
rough weather, the units were not retrievable for a week. Thus, fortuitously,
currents at Loiza were recorded continuously for about 140 hours. These
results are tabulated in Appendix D. A graphical representation of this
6.21
-------
data is given in Figures C-4 to C-6.
The first half of Figure C-4 shows cyclic shifts in the current
direction with a velocity maximum at every other shift to the east. The
pattern slowly fades at the end of the graph. Since the direction cycle
is semi-diurnal and the observation period of the first half corresponds
to spring tides (full moon) It suggests a tidal influence on the speed
and direction of the currents regulated as well by the monthly lunar
periodicity (spring-neap tides). However, longer periods of observation
will be required as tides seem to be only one of many factors affecting the
currents of this area.
The speed maxima corresponding to the eastward flow has a strong in-
fluence in the analysis shown in Figures C-5 and C-6 (net flow current
vectors). A detailed description of the computation of flow values for the
octants N, NE, E, SE, S, SW, W, NW is given in Appendix B. The vectors
represent sums of products of speed and duration of flow in each of these
octants. Figure C-5 corresponds to the inner shallow and outer shallow
meters. The east and west vectors were the longest in both cases, thus
they tend to cancel each other, giving a SW and just west of south resultant
at the outer and inner meters, respectively. It should be noted that
throughout the entire period of observation, parallel-to-shore or on-shore
currents prevailed with little, if any, off-shore component.
The results in Figure C-6 show an ESE resultant with an average speed
of 0.40 knot. It is possible that the general trend of flow for the entire
water mass for this period was in this direction, but that the wind had
an effect in reducing or deflecting the eastward component, giving a south-
6.22
-------
ward resultant for surface waters. Wind data records of the weather
bureau at the Isla Verde Airport showed a prevailing E to ENE direction
for the period of observation, with speeds of up to 20 knots recorded on
December 16. Winds from the S-SE prevailed at night, but the speed was
low (five knots or less).
One can conclude, from the results of the three cruises that the
current patterns at Carolina are very complex, and that a strong tidal
influence in both speed and direction exists. The spring tides have a
stronger influence than neap tides in affecting speed and direction. Based
on an analysis of the data, it appears that an easterly flow occurs on the
falling tide and a flow to the west during the rising tide for the majority
of the observations (see Figure C-4). These results seem to be contrary
to those presented in the Barceloneta report (4) for another north coast
area. The observation periods for current data at Barceloneta did not
exceed a period of 25 hours. Wind has an apparent influence in reducing
and/or deflecting easterly surface currents up to a maximum depth of ten
meters. The importance of prolonged current observations, covering periods
of full lunar cycles, becomes evident from Cruise 3 data, where the strong
influence of tidal effects is apparent.
Hydrographic Data
Hydrographic station locations are shown in Figure C-7- The tabulated
data and graphs of temperature and salinity values are given in Appendix D.
Surface density values obtained during Cruise 1 (Figure C-8) show no
negative gradient, with the lower values closer to shore which one might
well expect in this region which comprises the mouth of Rio Grande de Loiza,
the largest river on the Island. The values ranged from 23.60 to 23.80
6.23
-------
sigma-t units, with an average value of 23.79. Values obtained during
the second cruise ranged from 22.00 to 23.05 sigma-t units, with a small
but well-defined gradient (Figure C-9). The average value of sigma-t
was 22.82. The observed gradient was small when compared to results at
San Juan where a change of over two sigma-t units was observed within a
shorter distance. The strong prevailing currents in the area may account
for this low gradient as the river water may be rapidly dispersed.
Density profiles are given in Figures C-10 and C-ll. The important
feature to mention from the standpoint of the density is that values be-
tween 60 meters (the deepest that Engineering-Science suggests is at all
feasible for locating the waste outfall) and the surface varied from 0.40
to 0.80 sigma-t units during the first cruise and from 0.58 to 0.61 during
Cruise 2. This is in contrast to a change of 2.0 sigma-t units which
were found in the San Juan area. The greater density gradient in the San
Juan area was primarily the result of the low density surface water emerging
from San Juan Bay. This is evidence for the rapid removal or dispersion
by the currents of the low density water from the mouth of Rio Grande de Loiza.
Water Quality
One of the most immediately noticeable features of the sites was that on
the 23rd of April, the area studied was marked by a great deal of turbidity
due obviously to run-off from the Rio Grande de Loiza. On the 27th of April,
the waters were clear throughout the region. Figure C-12 shows the Secchi
disc readings in meters as an index of transparency. On the basis of the
6.24
-------
values alone, one would-be tempted to conclude that there is a central plume
of turbid water extending out into clear water. However, this is due entirely
to the differences in time. That is, on April 23rd, all the water in the
general area was turbid, and on the 27th, all the water was clear. These
changes in turbidity appear to be a combination of the amount of rainfall in
the watershed and the efficiency of the currents in removing the turbid
waters rather than the stirring up of bottom particles by high seas, since
the shallow water of this area was characterized by a rocky bottom and
coarse sand. Second cruise readings (Figure C-13) showed a plane of turbid
water west of the mouth of Rio Loiza.
The nutrient values obtained during both cruises were, as in San Juan,
very low. Since values were slightly higher than those of San Juan, ranging
from 0.20 to 0.60 mg/1 for Cruise 1. Cruise 2 showed even lower values,
ranging from 0.04 to 0.18 mg/1. Phosphorous values were so low that they
could be considered as traces (see Appendix C). The Coliform levels at
two stations off Punta Vacia Talega varied from 40 to 800 mf/100 ml.
Dissolved oxygen ranged from 4.93 mg/1 to 6.69 mg/1. Tables of water quality
data re included in Appendix D.
6.25
-------
I >
CURRENT METER
CRUISE 3
DROGUES %
CRUISE 2 f
CURRENT METER
CRUISE 1
IOO FMS
LAGUNA DE PINONES
^PUNTA
VACIA
TALE6A
LOIZA
ALDEA
10 FMS
0
L
J_
IMAUT MILE
g CAROLINA
<&
FIG C-l
CURRENT STATION LOCATIONS
CAROLINA SITE
M
PUNTA
MIQUILLO
-------
SHALLOW 5 M
I ST. SERIES
2ND SERIES
MID DEPTH 20 M
HIGH TIDE
-0=
2ND SERIES
DEEP (5 M
DEEP 40 M
HIGH TIDE
TIME 08
09
(0
II
MOON (3 ,4
15
16
0
L_
10
CM/SEC
20
I
*. RISING TIDE
*- FALLING TOE
FIG C-2
CURRENT VECTORS
CAROLINA SITE
CRUISE I APRIL- 23, 1971
WATER DEPTH 55M
HIGH TIDE 1136
6. ?7
-------
65°
1434
I22S
LOW TIDE
1533
1405
1619
#\ SURFACE
#11- 10 METERS
1604
Q H # 21- 25 METERS
SEE NOTE ON FIGURE SJ-3
J1 i I I
_! l_
NAUT MILE
FIG C-3
CLIRRENT DROGUES - CAROLINA
CRUISE 2
3 September 1971- SERIES 1-2-3
-------
PAGE NOT
AVAILABLE
DIGITALLY
-------
SENSOR AT MM
BOTTOM DEPTH 46M
TOTAL TIME I4I'5 HOURS
V = 0-33
V=0-3
37-5%T
V = 0- 23
19-7% T
V= 0-44
20.% T
V=0-58
21-2 % T
V=0-5I
24 9% T
SENSOR AT IIM
BOTTOM DEPTH ISM
TOTAL TIME 141-0 HOURS
PUNT;
VACIA TALE6A
__ V= 0-58
22.2 % T
fV=O-48
14 8 % T
V=0.5'3
FIG C-5
NET FLOW CURRENT VECTORS
CRUISE 3 16-22 DEC- 1971
CAROLINA
AVERAGE SPEED (V) IN Kn
AND PERCENT OF TOTAL
TIME SHOWN FOR EACH OCTANT
ARENAS'7^
0
L
0.5
_J
NAUT. MILE
6.30
-------
SENSOR AT 33M
BOTTOM DEPTH 45M
TOTAL TIME 142-2 HOURS
V=0.34
12 .9% T
5 8 % T
V - 0. 5
42-5 %T
10.3 % T
FIG C-6
NET FLOW CURRENT VECTORS
CRUISE 3 16-22 DEC 1971
CAROLINA
AVERAGE SPEED (V) IN Kn
AND PERCENT OF TOTAL
TIME SHOWN FOR EACH OCTANT
0
PUNTA
VACIA TALEGA
NAUT. MILE
-------
3*
NAUT MILE
25*
26*
27*
24*
23*
22*
8*
9*
7*
13*
14*
2*
15*
28* 21*
10*
4*
20*
19*
.PUNTA
.VACIA TALEGA.
.RIO GRANDE.
.DE
.LOIZA
11*
12*
.*.*LOIZA ALDEA.
5*
16*
17*
18*
6*
Figure C-7a
HYDROGRAPHIC STATION LOCATIONS
CAROLINA
CRUISE 1 23, 27 APRIL 1971
6.32
-------
NAUT MILE
8X
7X
20X
9X
10X
13X
19X
3X
6X 18X
11X
5X
15X
16X
12X 17X
.PUNTA
.VACIA TALEGA...
.RIO GRANDE.
.OE
.LOIZA......
2X
IX
,.B I......
, l.i
.*.*UOIZA ALDEA.
Figure C-7b
HYDROGRAPHIC STATION LOCATIONS
CAROLINA
CRUISE 2 24, 26 AUGUST 1971
6.33
-------
27 APRIL
23 APRIL
23.80
23.80
23.80
23.80
23.30 23.80
23.80 /23.
'
80
/
27 APRIL
/
23.80
23.80
23.80 23.90
/
23.90
23.90
23 70
23.80
23.80
23.90 / 23.90
23.90
FIG C-8
SURFACE DENSITY
AT CAROLINA SITE
CRUISE 1 23-27 APRIL I97I
-------
NAUT MILE
FIG O-9
SURFACE DENSITY
AT CAROLINA SITE
CRUISE 2 24-26 AUGUST
1-971
-------
STA * 24 23
SURFACED 2381 2334
20 19
20-J
40 H
60 -\
80 H
too H
120 H -
140 H
I6O H
180 J
DEPTH METER
FIG C- 10
DENSITY 6t
CENTRAL SECTION
CAROLINA SITE
CRUISE 1 27 APRIL I97I
0-5
i - 1 - 1
NAUT MILE
6.36
-------
DEPTH
IN
METERS
FIG C-ll
DENSITY £t
CAROLINA SITE
CRUIS-E 2
26 AUGUST 1971
h.37
-------
23 APRIL
27 APRIL
27.
2O i 16
LOIZA ALDEA
D LOIZA
FIG C-12
WATER TRANSPARENCY
CAROLINA SITE
SECCHI DISC READINGS IN METERS
CRUISE I 23,27 APRIL 1971
-------
7.S
26AUG ' 24 AUG
3-1
W /
1*3
RIO
GRAND E//DE LOIZA
NAUT Ml
FIG C-13
WATER TRANSPARENCY
CAROLINA SITE
SECCHI DISC READINGS IN METERS
CRUISE 2 24,26 AUG 1971
-------
HUMACAO/YABUCOA
Description of Study Areas
Because of the close proximity of the Humacao and Yabucoa sites,
they will be considered together in this section.
Puerto Yabucoa is situated on the southeast coast of Puerto Rico
facing eastward toward the Caribbean Sea. The bay stretches for 3.5 miles
from Punta Guayanes to the north to Punta Quebrada Honda to the south.
Puerto Yabucoa, which marks the eastern limit of the fertile valley of
Yabucoa, is unsheltered by reefs and thus is subjected to the strong prevail-
ing ocean currents.
Rivers draining into Puerto Yabucoa are the following:
(1) Rio Guayanes - the largest river in southeast Puerto Rico.
(2) Rio del Tngenio - flows to the southeast and joins the Rio
Guayanes one half mile before the latter reaches Puerto Yabucoa.
(3) Rio Santiago - passes through the city of Yabucoa and enters
Puerto Yabucoa at the same point as the Rio Guayanes.
(4) Two additional small streams run to the southeast and discharge
into Puerto Yabucoa.
At the present time, industrial activities in the vicinity of Puerto
Yabucoa are limited to a sugarcane processing plant and a recently constructed
petrochemical plant. Processing and waste waters from the sugar mill are
discharged into what is known as Barras Creek, which ultimately joins the
Rio Santiago (1). The degree of treatment and point of discharge of petro-
chemical waste is unknown.
6.40
-------
Sanitary wastes are collected in septic tanks and no further treat-
ment is provided to the effluents which discharge into the Rio Santiago
and eventually Puerto Yabucoa (1). Most dwellings in the community
called Playa de Guayanes discharge domestic wastes through pipes or ditches
into Rio del Ingenio which, as mentioned above, joins the Rio Guayanes
before discharging into Puerto Yabucoa.
The Rio Humacao originates in the mountainous section of Tejas in the
municipality of Las Piedras, Puerto Rico. Its point of origin is the
highest point in the watershed with an elevation of 1,025 feet above sea
level (2) . The R.io Humacao is 21 miles long and in its course runs mostly
through mountainous and unpopulated country until it reaches the flat low-
lands of Humacao City. Here, the terrain is flat all the way to the coast,
where the river flows into the Caribbean Sea (2). The Del Ingles Creek,
the Del Obispo Creek and the Catano Creek are the main tributaries of the
Rio Humacao.
In 1967 there were not more than ten industrial plants located along
the Rio Humacao watershed (2). Today there are numerous other industries
situated on the Rio Humacao, the largest of which is a recently constructed
pharmaceutical manufacturing plant.
The sewage treatment plant serving the town of Humacao consists of an
Imhoff tank with a BOD removal efficiency of about 25 percent and a sus-
pended solids removal efficiency of 30 percent (2). In addition to the
effluent from this obsolete system, leachates from the garbage disposal
site located 1.5 miles southeast of Humacao undoubtedly contribute to the
poor sanitary quality of the Rio Humacao (2). Also, as has been observed
in many other areas of Puerto Rico, people living in houses close to the
6.41
-------
river use its water for disposal of their domestic wastes.
Hydrodynamics - Hutnacao
The only information available on currents for the Humacao region
prior to this study were those given in the "Tidal Current Tables for
the Atlantic Coast of North America" (3) and the report on "Wastewater
Treatment and Ocean Disposal for Humacao Area" (4). The maximum currents
for Vieques passage according to (3) is 0.6 knots in a direction of 250°
during flood tide and 0.7 knots in a direction of 55° during ebb tide.
These values are, however, for a sound that is a considerable distance
(9 kms) from Humacao and which differs in bathymetric features from the
study site. The data obtained by (4) showed a clockwise tidal reversal
flow.
Three current surveys were carried out during the study at Humacao.
Figure H/Y-1 shows the location of the stations for each survey. Tabular
results for the first cruise, using an Ekman-Merz current meter, are given
in Appendix E, and current vectors are shown in Figure H/Y-2. The general
flow was roughly westerly (towards shore) in the surface and mid-depth
waters, and south to southeast in bottom waters. The average speed was 0.28
knots for the surface waters, 0.26 knots for mid-depth, and 0.34 knots for
bottom waters.
Figure H/Y-3 shows the results obtained with drogues during the second
survey. The general direction obtained with the drogues was to the NW for
the surface water with an average speed of 0.31 knots. The mid and deep
drogues showed a somewhat erratic course and a considerably lower speed.
6.42
-------
Current meter studies were carried out during the same period but due to
a malfunction, which was discovered only later during the study at Ponce,
this data has not been included as it is considered suspect.
More extensive observations were obtained during Cruise 3 when Hydro
Products Model 502 recording current meters were anchored for 27 hours.
The data obtained with the current meters is presented in Appendix E and
Figure H/Y-4. As shown in Figure H/Y-4, a fairly stable pattern is indicat-
ed with minor changes in speed and direction. No significant differences
were found in the current structures of inner and outer stations. The
general direction was southerly, with a change in direction toward the east
during the first half of rising tide periods. Drogue studies carried out
in conjunction with the current meter measurements showed considerably
more variation in direction, and lower resultant speed values. Such
differences are difficult to interpret because of rapid changes in the
bottom contour over small horizontal distances, with corresponding sudden
changes in current values to be expected. Also, because of the nature of
the bottom, no drogue data was obtained for currents as close to the bottom
as the sensors of the current meters. When attempts were made to do this,
the drogues ran aground almost immediately. The speed values obtained with
the in-situ recording meters agree roughly with the values obtained with
the Ekman-Merz meter during Cruise 1. A drogue x-ras lost on January 17 and
recovered on the 19th. Its path was toward the south-west at an average
speed of 0.1 knot. Current flow vectors, computed from the data obtained
with the in-situ recording meters, are shown in Figure H/Y-5. The length
of the component vectors corresponds to the actual quantity of flow (the
6.43
-------
sum of products of duration of flow and average speed) for each octant.
Average speed values, and percent of total time of flow in each octant,
are also given together with the average speed in the direction of the
resultant (labeled R in the figure). A detailed description of the method
used in this analysis is given in Appendix B.
Hydrodynamics - Yabucoa
Station locations for each of the three surveys are shown in Figure H/Y-1,
Cruise 1 tabular data is given in Appendix E, and Figure H/Y-6 illustrates
the results. Only two observations (with the Ekman-Merz meter) could be
made on May 6, 1971, due to weather conditions which caused the anchor line
to break. On this occasion there was a southerly current of a little over
0.4 knot in the shallow (5m) water, and a slightly weaker current at mid-
depth (12m). The site was revisited on May 19, 1971. Results with the
Ekman-Merz meter were rather erratic, particularly at mid-depth (Figure
H/Y-6), giving a low value of current speed. The wind velocities were
unusually low, varying from two to eight knots (see Section 4). Also, these
observations were made during a period close to the time of neap tides, so
that tidal influences were weaker than usual.
Drogue studies were carried out during Cruise 2 in winds of 12 to 16
knots from the ESE (Appendix E). The prevailing current was generally east-
ward from mid-morning to early afternoon (see Figure H/Y-7), with average
speeds higher than comparable values obtained during Cruise 1. During the
afternoon the currents shifted towards the north, as illustrated in Figure
H/Y-8. Tabular results of these current observations are given in Appendix E.
6.44
-------
Only one of the in-situ recording current meters was anchored during
Cruise 3 due to the very narrow shelf and abrupt slope, as explained in
Appendix A. Current meter results, based on 24 hours of continuous obser-
vation on January 17 , 1972, are shown in Figures H/Y-4 and H/Y-10, and
tabular data is included in Appendix E. Figure H/Y-10 shows the relative
quantities of water flowing in each octant, corresponding to the cardinal
and inter-cardinal points of the compass, together with the net resultant
current flow, as explained in Appendix B. In this case the current direction
and speed, as recorded by the in-situ meter, vras unusually constant. Current
drogue tracks obtained during Cruise 3 on January 18, 1972, are shown in
Figure H/Y-9.
Hydrographic Data
Hydrographic station locations at Humacao and Yabucoa are shown in
Figure H/Y-11. Hydrographic data, including temperature and salinity values
from which density (sigma-t) values discussed here were computed, are given
in Appendix E, Generally, the changes in water characteristics from surface
to bottom in shallow water and from place to place throughout Puerto Yabucoa
and the coastal waters of Humacao are slight. Figures H/Y-12 and H/Y-13
show the surface density (sigma-t) values obtained. There is little consistent
structure, probably due to the fact that this is a lee shore where the wave
action of the incessant on-shore winds keeps the waters well mixed, though
there is a tendency for slightly lower density values to be found closer to
shore.
Profiles of the center section of the Humacao and Yabucoa sites, illus-
6.45
-------
trating isopycnals at various depths, are shown in Figure H/Y-1A, II/Y-15
and H/Y-16. The values given were computed from temperature and salinity
values obtained during Cruise 1 and 2.
Water Quality
Water quality surveys for the Humacao and Yabucoa areas were combined
because of the proximity of these areas, and the continuity of the data.
Tables of data obtained during Cruise 1 and 2 are included in Appendix E.
During Cruise 1, Secchi disc readings varied between 2.5 and 22 meters
at these sites, as shown in Figure H/Y-17. As a rule, the depth contours
followed the coastline, indicating that no turbid plumes projected out into
the ocean. Silica concentrations varied between 0.1 and 0.6 mg/1, and
phosphorus was below measurable values in most of the samples, reflecting
the low phosphorus levels generally found in the Caribbean Sea.
On the second cruise, Secchi readings varied between 3 and 42 meters,
as shown in Figure H/Y-18. These readings are consistent with prior obser-
vations except for a plume off Morro de Humacao, which may have been caused
by the outflow of Rio Humacao. Oxygen concentration was found to be be-
tween 5.39 and 6.73 mg/1, showing little oxygen depletion. Silica con-
centrations varied from 0.09 to 0.51 mg/1, and phosphorus was found in con-
centrations between 0.008 and 0.020 mg/1, neither of which is deemed signifi-
cant. The coliform MPN levels varied between nil and 200/100 ml.
6.46
-------
HUMACAO
CAYO SANTIAGO
CURRENT METERS
CRUISE 3 T
CRUISE 2 J/
DROGUES^/
CRUISE 3
* / \
' ' /
i ' /
v-\
/ \
I
loOFM
CURRENT METER
CRUISE I
FIG H/Y-I
CURRENT STATION LOCATIONS
HUMACAO AND YABUCOA
0
L_
_L
NAUT Ml
-------
SHALLOW
4M LOW TIDE
__r~x -fb-~i
/ '
/ / 1
\
1 ^ ~H"> 1
\^
/ /
/
HK5H TIDE
TIME
07 08 09 10
II 12
NOON
13 14 15 16 17 18
10 20 Cm/Sec.
0.25 0-5 Kn
MID DEPTH
12 M LOW TIDE
FALLING TIDE
RISING TIDE
HIGH TIDE
FIG H/Y-2
CURRENT VECTORS
HUMACAO
CRUISE I 10 JUNE 1971
DEEP 20M
HIGH TIDE
-------
,1655
1608
I8°5'
I8°07'
15 12
1504
I2TC)
1110
I320" 1215 FOR 20M.
1648
FIG H/Y-3
CURRENT DROGUES
HUMACAO SITE
CRUISE 2 SEPT- 20 1971
0 0 SURFACE
A A MID DEPTH
Q Q DEEP 20M.
65°45'
-------
. HUMACAO INNER
HUMACAO OUTER
. YABUOOA
Ol
o
360
270
III
i
I
I-
o
u
5 90
\ \
,x
0-8
I
*"^S». .-~"~~?f*r' * -^
TIME 1400
DATE 17/1
I80O
22 OO
0000
18/1
0200
O40O 0600 080O IOOO I2OO I4OO WOO
FIS H/Y-4
CURRENT VEUOCITY
CRUISE 3 17-18 JANUARY 1972
HUMACAO AND YABUCOA
-------
N
CAYO SANTIAGO
SENSOR AT 8M
BOTTOM DEPTH 9M
TOTAL TIME 24-0 HOURS
V=0-26
9.2 %T
V= 0-26
2%T
SENSOR AT ISM
BOTTOM DEPTH 20V
TOTAL TIME 24 HOURS
V= 0.25
6-2%T
V=0-25
19-6 %T
PUNTA
QUEBRADA
HONDA
CURRENT VECTORS
17-18 JANUARY 1972
FIG H/Y-5
NET FLOW
CRUISE 3
HUMACAO
AVERAGE SPEED (V) IN Kn
AND PERCENT OF TOTAL TIME
SHOWN FOR EACH OCTANT
V=0.28
62.5 %T
-------
SHALLOW
LOW TIDE
-O
-O
HIGH .TIDE
0
0
10
20 Cm/Sec
0-25
0-5 Kn
RISING TIDE
FALLING TIDE
MID DEPTH
LOW TIDE 0917
HIGH TIDE 1741
DEEP
07
13
14
I
15
I
16
HIGH
TIDE
I l I
17
18
WATER DEPTH 35-40 M-
WIND EAST FORCE 2-3
6.52
FIG H/Y-6
CURRENT VECTORS
YABUCOA
CRUISE I 19 MAY 1971
-------
909
ASHORE
PUNTA
QUEBRADA
HONDA
0.6
N A U T MILE
FIG H/Y-7
CURRENT DROGUES
YABUCOA SITE
CRUISE 2 SERIES1-3
SEPTEMBER 16,1971
00 SURFACE
A& MID DEPTH
00 DEEP WATER
SEE NOTE ON FIGURE SJ-3
-------
1640
FIG H/Y -8
CURRENT DROGUES
YABUCOA SITE
16 SEPTEMBER 1971
CRUISE 2 - SERIES 4-5
0 O SURFACE
MID DEPTH
0.5
NAUT, MILE
18° 03'
PUNTA
QUEBRAOA
HONDA
&I620
1624
/SERIES 5
1429
-------
o
A 1129
B 1137
C 1236
D 1336
FIG H/Y-9
CURRENT DROGUES AT YABUCOA SITE
JANUARY 18, 1972 CRUISE 3
SERIES
00 SURFACE
&A MID-DEPTH 5M.
SCALE NAUTICAL MILE
-------
PUNTA
QUEBRADA HONOA^
SENSOR AT 8M
BOTTOM DEPTH 9M
TOTAL TIME 24-0 HOURS
V= 0.3
4-2%T
PUNTA
VYEGUAS
0.5
_)
FIG H/Y- 10
NET FLOW CURRENT VECTORS
CRUISE 3 17-18 JANUARY 1972
YABUCOA
AVERAGE SPEED (V) IN Kn
AND PERCENT OF TOTAL TIME
SHOWN FOR EACH OCTANT
V=O-29
95.6%T
NAUT MILE
6.5'-)
-------
.HUHACAO.
.8.11
.1.11
.*.**...YABUCOA.
.III.
.III.
.20*
19*
18*
19*
20* 21*
30*
29*
22*
28*
27*
23*
6*
26*
25*
5*
12*
3*
2* 1*
11*
10*
8*
9*
18*
/ 17*
// 16
7*
1*
7*
// 15*
// 13*
// 14*
2* //
// HUMACAO
3* //
// 0
4* //
8*
5*
6*
9*
17*
.13*
14*
10*
11*
15*16*
12*
24*
Figure H/Y-lla
HYDROGRAPHIC STATION LOCATIONS
HUMACAO-YABUCOA
CRUISE 1 30 APRIL, 5, 18 MAY 1971
6.57
-------
BBB.
Mf.
.HUMACAQ .III.
***.
.B.BS ,
.a.SB.
.***...YABUCOA.
IX
18X
17X
16X
15X
14X 13X
IOX
HX
12X
IOX
20X XZ1
22X
23X
X15 X24
11X
12X
16X
17X
25X
BOX
29X
28X
IX
27X
2X 3X
5X
7X
//
//
8X //
18X JhX
6X
7X
HUMACAO
2X
6X
3X
9X //
//
//
// NAUT MILE
///
//
YABUCQA
13X
Figure H/Y-llb
HYDROGRAPHIC STATION LOCATIONS
HUMACAO-YABUCOA
CRUISE 2 9, 14, }5 SEPTEMBER 1971
6.58
-------
HUMACAO
.22.81
.22.88
23.42
2 Mile
22.94
23.13
.23.13
»22.96
,23-01
23.09
.23.15
23.06
FIG H/Y- 12
SURFACE DENSITY
HUMACAO AND YABuCOA SITES
CRUISE I 30 April TO I 9 May 1971
-------
HUMACAC
0
L
ZMile
NAUT MILE
22-18
22.17 22.08 22 06
22.07
22.01 22.05
22.26
YABUCOA
FIG H/Y-13
SURFACE DENSITY
HUMACAO AND YABUCOA SITES
CRUISE 2 9,14,15 SEPTEMBER 1971
-------
CRUISE I
6 543 2
23.21 23-38 23.43 23-39 23.44
^T7~7~^7^^^^--^~^^ ^0.4-i" : ^4°-4" \
? ? -^T-T-T^-T-^ , /X/////^^^^^7^^y>^^^^
' STA#-
23-46 SURFACE 6t
«
*
4
- o
->(\
CRUISE 2
DEPTH IN
METERS
STA # |4
SURFACE dit 2|.64
0
20-
V^
15
21.56
16
21,54
17
21.63
18
21.81
' f ' '/'/// / / ////////////////x//
0
L
a 5
NAUT
MILE
FIG H/Y-14
DENSITY 6$
CENTRAL SECTION
HUMACAO SITE
CRUISE I 30 APRIL 1971
CRUISE 2 9SEPTEMBER 1971
-------
STA/4 2Q
SURF.dt 22.67
17
22.13
0
L_
0.5 NAUT Ml
h 20
i- 40
U 60
U 80
U 100
M 20
h 140
f 160
h I 80
\- 200 M
FIG H/Y- 15
DENSITY
-------
40
60
80
100
120-
140-
160
180
200
220
FIG H/Y-16
DENSITY OJ
CENTRAL SECTION
YABUCOA BAY SITE
CRUISE 2
15 SEPT. 1971
240-
260-
280-
0
I
0.5
NAUT MILE
6.63
PUERTO RICO OCEANOGRAPHIC PROGRAM
-------
'HUM ACAO
o
NAUT Ml
FIG H/Y-17
WATER TRANSPARENCY
HUMACAO YABUCOA SITES
SECCHI DISC READINGS IN METERS
CRUISE I 30APRILTO 19 MAY 1971
YABUCOA
2.2-
16.
12-
9.
16- 24-
-------
HUMACAO
5-9
10.5
13-
NAUT Ml
FIG H/Y-18
WATER TRANSPARENCY
HUMACAO-YABUCOA SITES
SECCHI DISC READINGS IN METERS
CRUISE 2 9,14,15 September 1971
o-
YABUCOA
-------
GUAYAMA
Description of Study Area
The area considered in this section lies along the southern coast
of Puerto Rico between Punta Figuras and Punta Ola Grande. The major
urban centers in this area are Guayama and Arroyo. Generally, the coast
is highly irregular with numerous sparsely-vegetated projections. Shoals
and fringing reefs, either partially or totally awash, are abundant. Host
of the time the sea is rough and choppy even at short distances from shore
(1). Rainfall is considerably less than in most other parts of the Island,
averaging 60 inches a year at Guayama (1). Rio Nigua and Rio Guamani at
Arroyo and Guayama, respectively, are the only streams of importance which
discharge into the Caribbean Sea between Punta Figuras and Punta Ola Grande (1)
A preliminary waste water management report (2) provides the following
information on domestic and industrial waste water in this region. The city
of Guayama is partially sewered, the raw sewage being discharged directly
into the Caribbean through an 18 inch cast iron outfall built in 1937- The
discharge is about three feet above the water level and 100 feet from shore
on a trestle at a point called Punta Barrancas due south of Central Machete.
Calculated flows through this pipe fluctuated from a high of 2.72 mgd to
a low of 0.88 mgd.
In March 1971, there were 25 industries operating in Guayama, 17 of
which are connected to the sewage system (2). The most important industrial
operations affecting the quality of coastal waters are an oil refinery, two
sugar mills, a pharmaceutical products manufacturing company (produces
6.66
-------
vitamin B-12 and other vitamins) and three fabric dyeing plants (1) .
Plant washings and excess process water generated in these operations
are discharged into the Caribbean Sea in this area. Plant cooling
xjater, excess process water, and domestic waste from Central Machete
sugar mill, however, are conveyed directly into Guayaina's main sewer pipe.
Hydrodynamic Data
Various current measurements had been made prior to the present study
in the Guayama coastline area. They all were done with the constraint of
the present study, i.e., a limited time of continuous observation. The
first report, including current measurements, was conducted by Munoz (1967)
under the sponsorship of the Department of Health (1). Drifting drogues
submerged three feet below the surface were used at distances of 50, 100,
and 300 meters from shore. The general flow of the current was found to
be to the west at speeds fluctuating between 0.1 and 0.4 knots. A semi-
I
circular gyre about 300 meters in diameter was observed from the drogue
paths at Punta Barranca.
A second study was carried out in the same year by P.R.A.S.A. (3).
The method used was to follow the path of wood blocks. A Gurley current
meter was used to confirm the velocity results. The general flow path was
found to be westward with an onshore component being evident in the majority
of the observations.
The most comprehensive study of currents at Guayama was carried out by
Ileres (2) who released large numbers of drogues at different depths at
various locations between Punta Figuras and Punta Conzuelo. Again,
6.67
-------
the general flow was to the west at varying speeds. However, an eastward
flow prevailed on April 16. 1970. Unfortunately, the time when current
measurements were taken was not provided in any of the reports. In some,
not even the date is included, thus no analysis of the influence of tides
can be made.
The station locations for the current measurements obtained during the
three cruises of the present study are given in Figure Gm-1. The current
meter data is listed in tabular form in Appendix F, and graphs of the data
are shown in Figures Gm-2 through Gm-7.
In 20 of the 36 individual current measurements made with the Ekman-
Merz meter during Cruise 1, bi-modal currents may have been present as
shown by the distribution of balls in two separate sectors of the compass
cup. As was done in the cases of this nature off the east coast of Puerto
Rico, the average direction was calculated using all the data, and the
bi-modal currents were calculated by treating the two main sectors sepa-
rately. Both the single and the bi-modal currents are listed in tabular
form in Appendix F. Only the single mode currents are illustrated in
Figures Gm-2 and G.m-3.
It is sometimes claimed that the yawing of the boat at anchor is re-
sponsible for the apparent double current. The boat does, indeed, swing
slowly back and forth several times during the recording period, which
is usually 10 minutes for each observation. However, if this view is
accepted, one is then forced to explain why this bi-modality occurs in
more than half of the observations at the Guayama site, less than half the
observations in the Humacao River and Yabucoa Bay sites, and not at all
6.68
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on the north coast of the Island at the San Juan and Carolina sites.
Presumably, the boat was yawing more or less the same at all these places.
The outstanding feature of the results of the Cruise 1 current
measurements off Guayama is the reversal of the current at depth. This is
shown clearly in Figures Gm-2 and Gin-3. Figure Gin-3 illustrates resultant
net flow vectors for each of the three depths, where the length of each
vector is proportional to the relative quantity of water flowing in the
indicated direction, and the average speed (v), which is simply a numerical
average of the speed at the corresponding depth without regard to direction,
is also given (see Appendix B) .
As can be seen in Figure Gm-2, vectors illustrating surface currents
as measured by the Ekman-Merz meter are predominantly westerly with a
spread of 47° betxreen the two most divergent vectors. During the last four
hours of observation of surface currents no vector differed by more than 2°
from 275° true. No hint of bi-modal currents was found during this
period. Only three of the 12 observations at the surface showed signs of
bi-modality. At ten meters the current was similarly towards the west, at
a slightly lower speed. The flow wavered back and forth more than at the
surface, and an analysis of the data suggests the presence of bi-modal
currents in nine of the 12 observations. At the 20 meter level, x^hich is
only two meters off the bottom, the current was directed strongly towards
the east with a resultant direction of 112° true. During the last 2.5
hours of observation, this current slowed down and turned towards the
northwest. There is no way of knowing whether this might be related to a
tidal factor or not. The wind was blowing steadily from E by S (southeast
6.69
-------
quadrant) between nine and 16 knots (Appendix F). The observed pattern
at the three different depths suggests a strong wind effect on the surface
waters.
Drogue studies were carried out during Cruise 2. Results are illustated
in Figure Gm-4, and tabular data is given in Appendix F. At the surface,
the current was initially towards the west and south, with a shift towards
the north (shoreward) at around 1230 hours. According to the Tide Tables
(4), low tide occurred at Arroyo, about 5.5 miles to the east of Punta Ola
Grande, at 1130 hours, but because of complicating factors resulting from
the fact that the tides (again, according to the Tables) are chiefly diurnal
in this area, the times computed from the Tables are of doubtful accuracy.
Surface current continued generally towards the north, with some shifting
towards the east, during the following four hours. Maximum speed was about
0.7 knot. The five meter (mid-depth) drogue spiraled very slowly for almost
four hours, then settled down on an ENE track at about 0.3 knot. The eight
meter (deep) drogue remained practically stationary for about five hours,
as can be seen in the figure. It is to be noted that the strong north-
bound surface current was not observed during the other cruises. Wind was
from the E or ENE at speeds generally between nine and 15 knots (see Appendix
F).
Three in-situ recording current meters were anchored during Cruise 3.
Failure of the corrodable links prevented retrieval of the instruments at
the time scheduled, and recording of current data was continued for a period
of six days. The results of the third cruise current measurements are shown
in Figures Gm-5, Gm-6 and G'm-7. Tabular data for speed and direction is
6.70
-------
given in Appendix F. Figure Gm-5 shows graphs of current speed and
direction plotted against time as recorded by the three instruments.
Figures Gm-6 and Gm-7 illustrate the results of an analysis giving the
actual quantity of flow into each of eight direction sectors centered
about the cardinal and inter-cardinal points of the compass (see Appendix B).
From the figures it is apparent that the general direction of flow is
in the south-western quadrant, with the outer deep meter registering the most
southerly flow. Cyclic variations in direction, corresponding roughly to a
sernilunar period, are also apparent in Figure Gm-5. The Tide Tables list
the tides at Arroyo, about 5.5 miles to the east of Punta Ola Grande, as
being chiefly diurnal. Thus, tide data from the Tide Tables does not
agree with the timing of what appear to be tidal effects in Figure Gm-5.
Nydrographic Data
The Guayama hydrographic stations were situated near Punta Ola Grande
on the southern coast of the Island on a broad (seven miles wide or more),
shallow (25 fathoms deep or less) shelf. About ten miles eastward along the
coast the shelf suddenly narrows to about 1.5 miles.
Tables of data for temperature, salinity, and density (sigma-t) are
given in Appendix F. The locations of these hydrographic stations are shown
in Figure Gm-8. Figures Gm-9 and Gm-10 illustrate surface density patterns
observed during Cruise 1 and 2, respectively, and Figure GH-11 shows density
profiles of the center section of the site as observed during the two
cruises. The largest temperature variation in the profiles in only 0.3°C.,
and the largest salinity variation is 0.21. As can be seen in the density
6.71
-------
profiles shown in Figure Gm-11, the greatest variation in sigma-t is
about 0.25. Thus, though there appears to be an overall seasonal variation
in density, the water remains well mixed and probably no amount of mixing
of waste water with ocean water at the bottom will prevent the waste water
from rising to the surface. The prevailing wind is from the east, with
an onshore component during the day, and an offshore component at night.
Consequently, there is a possibility that wastes on the surface would be
blown ashore.
Water Quality Data
Tables of xrater quality data obtained during Cruises 1 and 2 are in-
cluded in Appendix F. Only Secchi disc readings and samplings for silica
and phosphorus were taken during Cruise 1. The transparency readings showed
there to be no major zones of turbid water or decreases in transparency
close to shore, as can be seen from Figure Gm-12. Silica and phosphorus
readings were low (0.0 to 0.1 rag/I and 0.00 to 0.08 mg/1, respectively).
On the second cruise, Secchi disc readings showed an area of turbidity
east of Las Marens with little turbidity elsewhere (Figure Gm-13). Dis-
solved oxygen concentrations were uniformly in the 6-7 mg/1 range. Silica,
where measured, x^as in the range of 0.20 to 0.35 mg/1, and phosphorus
readings varied from 0.0007 to 0.0014 mg/1. Coliform MPN levels varied
from 1 to 100/100 ml.
6.72
-------
PTA, FIGURAS
ARROYO
CAYOS
CARIBE
.','PUNTA OLA
i, GANDE ,---
CAYOS DE BARCA
CUgRENT MET6RS
CRUIS~E~3 " "
CURRENT METER
CRUISE
DROGUES
CRUISE 2
FIG GM-I
CURRENT STATION LOCATIONS
GUAYAMA SITE
10 FM
10OFM
MAR CARIBE
O
I
2MILES
NAUT MILE
-------
SHALLOW
5M-
MID DEPTH
IOM
DEEP
20 M
WIND SPEED 14
IN KNOTS
II
15
16 16
TIME 06 07 08 09
10
14 14 14
14
10
16
0
10 20Cm-/Sec
0-25 0-5 knots
FIG GM-2
CURRENT VECTORS
GUAYAMA
CRUISE I JUNE I 1971
DEPTH OF WATER 22M.
6.74
-------
PUNTA
COLCHOIMES
CAYOS DE BARCA
5 M V = 0-32
0
!_
I
NAUT MILES
FiG GM-3
RESULTANT NET FLOW VECTORS
AT DEPTHS OF 5,10 AND 20METERS.
CRUISE I I JUNE 1971
GUAYAMA SITE
TOTAL TIME OF OBSERVATION
FOR EACH RESULTANT
ABOUT 9 HOURS-
DEPTH OF WATER 22 METERS
AVERAGE SPEED (V) IN Kn
-------
i7°5S'
PUNTA OLA
GRANDE
I 7° 5 3'
AREA OP
DROGUE
MOVEMENT
FIG GM4
CURRENT DROGUES
GUAYAMA SITE
23 SEPTEMBER 1972
SERIES 1-2-3
CRUfSE 2
0 0 SURFACE
A A MID DEPTH 5M
0 Q DEEP 8M
1615
t23O
0.5
NAUT Ml
-------
PAGE NOT
AVAILABLE
DIGITALLY
-------
PUNTA OLA
GRANDE
SENSOR AT IOM
BOTTOM DEPTH IIM
TOTAL TIME 134-5 HOURS
V = 0-344
5. 0 % T
V = 0-35
14- 8 % T
IT-8 %T
0
I
O-5
NAUT. MILE
SENSOR AT II M
BOTTOM DEPTH 23M
TOTAL TIME 135. HOURS
V = 0-26
0- 9 % T
V =0-33
59-3%T
0-37
15.5% T
V= 0.24
43%T
V=0-2I
99% T
V=0-27
10-3% T
FIG GM-6
NET FLOW CURRENT VECTORS
CRUISE 3 20-26 JANUARY 1972
GUAYAMA
AVERAGE SPEED (V) IN Kn
AND PER CENT OF TOTAL
TIME SHOWN FOR EACH OCTANT
-------
PUNTA OLA GRANDE
0-5
NAUT MILE
SENSOR AT I8M
BOTTOM DEPTH 23M
TOTAL TIME 140-5 HOURS
V= 0-33
16 % T
= 0-27
13-3 %T
V = 0.30
= O-29
24 -I %T
FIG GM-7
NET FLOW CURRENT VECTORS
CRUISE 3 20-26 JANUARY 1972
GUAYAMA
AVERAGE SPEED (V) IN Kn
AND PER-CENT OF TOTAL
TIME SHOWN FOR EACH OCTANT
6.79
-------
.GUAYAMA.
PUNTA
A DE JOBOS....
PTA
POZUELO..
CAYOS CARIBES
25*
26*
1*
.JOBOS.
PTA. OLA.
GRAND...
2-V*
13*
2*
23*
22*
3*
27* <*
15*
12*
11*
21*
28* 5*
20*
19*
6*
7*
16* 10*
17*
18* 9*
8*
NAUT MILE
Figure GM-8a
HYDROGRAPHIC STATION LOCATIONS
GUAYAMA
CRUISE 1 25, 26 MAY 1971
6.80
-------
.B.C.
.1.1.
.1.1.
.*.*.
.GUAYAMA.
PUNTA
A DE JOBOS...,
PTA
POZUELO.
.JOBOS.
PTA. OLA.
GRAND...
CAYOS CARIBES
NAUT MILE
19X
20X
21X
22X
23X
24X
30X
29X
28X
27X
26X
25X
6X
5X
3X
2X
IX
18X
17X
16X
15X
14X
13X
Figure GM-8b
HYDROGRAPHIC STATION LOCATIONS
GUAYAMA
CRUISE 2 23 SEPTEMBER 1971
6.81
7X
8X
9X
10X
11X
12X
-------
FIG- GM -9
SURFACE DENSITY AT
GUAYAMA SITE
CRUISE I 25,26 MAY 1971
25 MAY
26 MAY
2Mlle
-------
21-90
21-90
21-85
FIG G M-IO
SURFACE DENSITY
GUAYAMA SITE
CRUISE 2 25 Sept. 1971
2Mile
NAUT MILE
-------
CRUISE
CRUISE 2
21.86
METER
FIG GM -II
DENSITY
CENTRAL SECTION
GUAYAMA SITE
CRUISE I 25,26 MAY 1971
CRUISE 2 23 SEPT 1971
NAUT
0-5
MILE
-------
I5M
20M
19.
O
L_
Ml
FIG GM-12
,N METERS
, 26 MAY I 971
-------
Ponce
Description of Study Area
The city of Ponce, with a population of 114,000, is the second largest
city in the Commonwealth. Ponce is located 2 miles inland from the port,
which is called Playa de Ponce.
Bahfa de Ponce, situated on the south coast of Puerto Rico, is located
at latitude 17°58' and longitude 66°37'. The bay is the most important
commercial harbor on the south coast and one of the three leading ports of the
island. The prevailing tides at Ponce Bay are diurnal, with a range of up to
about 1.1 feet.
Prevailing winds in the area are from the easterly quadrant throughout
the year. Close to shore, diurnal effects due to sunlight heating the land
tend to produce onshore winds during the daytime and offshore winds at night.
The harbor itself is protected from the prevailing easterly trade winds by
Punta Penoncillo and Gayo Gata with their surrounding reefs, but it is exposed
southward. It is reasonable to expect that the prevailing westerly set of the
ocean currents off the southern coast of the island would be modified by local
conditions closer to shore.
Untreated domestic sewage enters the bay through two separate outfalls
with a total flow of approximately 9.4 MGD (1). The Hostos outfall is submerged,
extending 200 meters from shore while the Pampanos outfall, one foot above the
water surface, discharges about 250 meters from the shoreline. It has been
observed that sewage is quickly blown onshore by the prevailing winds (1), and
that the receiving waters are unable to assimilate and disperse the pollutants
(2). It has been estimated that the raw sewage being discharged into Ponce
Bay is at present contributing about 19,400 pounds of BOD^ daily (1) to the
receiving waters.
6.86
-------
There is also considerable industrial activity in the area adjacent to
Bahxa de Ponce. At the Ralston-Purina Tuna Fish Packing Plant about 150 tons
of tuna fish per day are processed, with the resultant discharge of wastes
rich in proteins, oils, fish meat, bones, and other organic constituents into
Ponce harbor. The Ponce Tanning Corporation and the Municipal Slaughterhouse
also discharge all liquid and solid wastes into the bay. Other sources of
pollution include several textile and commercial establishments located in
the area of Playa de Ponce.
Pollutants also enter Bahia de Ponce from two major river watersheds.
The Rio Matilde discharges just west of Punta Penoncillo. The Rio Portugues
is another river which courses through Ponce, although it is on rare occasions
that the river flow is sufficient to reach the ocean.
Hydrodynamics
Current studies prior to the present surveys were carried out at Ponce
in 1969 (2), using drifting floats. It was found during this study that the
surface currents have a net flow to the NE at speeds of 12 to 40 era/sec, and,
during two night observations, the floats were found to drift towards the SW.
Similar results are reported by Rafael A. Domenech (1), as quoted from a survey
report by P.R.A.S.A.
The studies at Ponce Bay followed procedures similar to those used at
the other sites, but Cruise 3 was omitted for this area. In Figure P-l the
station locations for the study are given. The results obtained with the
Ekman-Merz meter during the first cruise are shown in Figure P-2, and tabular
data is included in Appendix G. For surface waters the results were similar
to those obtained during previous studies. However, there was a shear
present as indicated by a net movement to the SE at a depth of 8 to 9 meters.
As can be seen from Figure P-2, the shear occurred at 0926 hours, one hour after
low tide. A clock-wise reversal began at 1450, resulting finally in a flow
6.87
-------
in the same direction as the surface water. Again as at other sites, a
bimodal pattern prevailed with the exception of two observations out of a
total of 42. The speed varied from 9.9 cm/sec with the first early morning
observation (0633), to above 30 cm/sec in mid-afternoon, for surface waters.
Slightly lower values were recorded at a depth of 9 meters.
As at the other sites, both an in-situ recording current meter and
drogues were used at Ponce to measure currents during Cruise 2. It was at
Ponce, however, that it was discovered that the recently borrowed recording
current meter had not been functioning properly. Subsequent attempts to correct
the malfunction of this particular recording meter proved unsuccessful, and
the questionable results obtained with this meter during Cruise 2 were discarded.
Drogue data from Cruise 2 is shown in Figure P-3, and tabular data is
given in Appendix G. Again a shear is evident in Figure P-3, were flow was
observed to be toward the east for the deeper drogue. All observations were
made during flood tide. The deeper (5m) drogue was seen to veer toward the
west at around 1310 hours, which, according to the Tide Tables (3), was half-
way through the flood tide cycle. It has so far been impossible to establish
any clear tide pattern influence on the currents at Ponce, as well as at other
areas on the south coast. The Tide Tables were used to determine times of high
and low tide. The reference station for this area of the south coast is
Galveston, Texas, for which corrections of -6:30 hours for high tide and -12:00
hours for low tide are indicated. Though the Tide Tables do state that in
eases where tides are listed as chiefly diurnal, as at Ponce, the computed times
"are intended primarily for predicting the higher high and lower low waters,"
the results are nevertheless rather odd at certain times. It is felt that a
more reliable source of tide data must be obtained if the tidal influence upon
currents on the south coast is to be understood. At this writing it is expected
that a recording tide guage will shortly be made available for use by the
Oceanographic Project, and that results obtained with this instrument together
6.88
-------
with further current data will be published in the near future.
It has been concluded from an evaluation of the data obtained for Ponce
that the prevailing flow of surface waters is shoreward in a NW direction,
whereas the deeper water oscillates from NW to SE with no clearly-defined tidal
relation. This, however, is not necessarily a representative pattern as
continuous data for a considerably longer period will be required to obtain
a more representative picture of the overall current pattern for the area.
Hydrographic Data
Hydrographic station locations are shown in Figure P-4. The hydrographic
station data is given in tabular form in Appendix G, and water density values
computed from these results are shown in Figures P-5 through P-8. The discolored
waters of the inner bay are approximately 1°C warmer than the surface waters
found outside the bay, and further along the coast to the east. A small
horizontal gradient exists with the most turbid inshore x^ater being a few tenths
of a degree warmer than the slightly less turbid off-shore water. Temperatures
at five meters are not significantly different from those at the surface.
Surface salinity values average about 0.2 percent less than the values
at Guayama. Again, a slight horizontal gradient exists, the inshore water being
slightly less saline (about 0.1-0.2 percent) than that offshore. The surface
density, given as sigma-t in Figures P-5 and P-6, shows a similar pattern.
It averages about 0.4 sigma-t units less dense than the surface water at Guayama,
and a horizontal change of about 0.3 sigma-t units is present with the offshore
waters being the more dense.
Profiles of temperature, salinity, and sigma-t along sections within the
inner bay are not definitely structured. The density profile for the section
running offshore along the western side of the survey area for Cruise 1 is
shown in Figure P-7, whereas for Cruise 2 the offshore section along the
6.89
-------
eastern side has been shown in Figure P-8. As is apparent from the data in
these figures, no significant density contrasts are present in the inshore area.
Thus, within the inner bay no amount of mixing and dilution is expected to
prevent the waste plume from rising to the surface of the bay where it now is.
It is only at the outer stations where strong temperature, salinity, and resulting
density gradients are found.
Water Quality
Water quality data was collected in the Ponce area during both cruises.
Results are given in Appendix G. Secchi disk readings varied between 1.5 and
9 meters, with the bulk of the observations being between 1.5 and 3 meters
(Figure P-9). These values are indicative of turbid water. However, the silica
and phosphorus readings were low (0-0.1 mg/1 and 0.00 to 0.01 mg/1 respectively),
indicating that there was a low level of nutrients present in this area.
On the second cruise Secchi depths were a little deeper, indicating less
turbidity (Figure P-10) . Readings varied from 2 to 24 meters, the majority being
between 2 and 4 meters. The dissolved oxygen concentration varied between 6.07
and 7.19 mg/1, close to saturation. Coliform MPN levels were low (between 50
and 90/100 ml), as were silica and phosphorus concentrations (0.03 to 0.10 mg/1
and 0.013 to 0.031 mg/1 respectively).
6.90
-------
IOFM
^ "
\
\
\
\
X
/
/
\
1
X
\ ^
N^.
s'
/
/
100 FM
to
MAR CARIBE
NAUT MILE
/
1
FIG P-l
CURRENT STATION LOCATIONS
PONCE SITE
(J
ISLA CAJA
DE MUERTO
-------
SHALLOW 4 M
LOW TIDE
DEEP 8 M
TIME 06 07 0.8 09 10 II 12 13 14 15
16
WIND SPEED
IN KNOTS.
10 II 10 13 15 16 21 20 20 21 23 23 21 2010 20 21 23
WIND DIRECTION EAST SOUTH EAST
10
20 CM/SEC
I
0.25
O.5 KTS.
FIG-P-2
CURRENT VECTORS
PONCE
CRUISE I JUNE 4 1971
LOW TIDE 0827
6.92
-------
0
L
0.5
i i i , I i
NAUTICAL MILE
LAGUNA DE
LAS SALINAS
-LUl
1628
1425
1310
1223
101
0917
0913
FIG P-3
CURRENT DROGUES
PONCE 28 SEPT. 1971
0 0 SURFACE
AA MID DEPTH 5M
SEE NOTE ON FIGURE SJ-3
-------
12* 10*
15*
16*
17*
0.5
NAUT KILE
. ..PLAVA DE.
...PONCE....
fl* 7* 3* 2*
4* 1*
9* 6*
Figure P-4a
HYDROGRAPHIC STATION LOCATIONS
PONCE
CRUISE 1 3 JUNE 1974
6.94
-------
16X
9X
15X
MX I IX I?X
IOX
ax
UX
JX
NAUT MILE
3X
Figure P-4b
HYDROGRAPHIC STATION LOCATIONS
PONCE
CRUISE 2 27 SEPTEMBER 1971
6.95
-------
RIO MATILDE
PLAYA DE
PONCE
22.90
0
NAUT MILE
0-5
i
22.92
22.90
23-00
FIG P-5
SURFACE DENSITY 6
PONCE SITE
CRUISE I 3JUNE 1971
23.06
6.96
-------
PLAYA
OE
PONCE
0
L
0-5
NAUT MILE
FIG P6
SURFACE DENSITY 6i
PONCE SITE
CRUISE 2, 27 September 1971
-------
STA #
SURF.S'T 22-90
_
" "22.9 ...
~- 23
16
22-63
-.A / /
15
22-77
/ / /~~f i / / i <
14
22 78
i
' '
13
22-76
~^-r-n r rr-r-r-r
12
22 72
-r^r-rrr^^7
40 -
60-
80
100 -
120-
140-
160-
DEPTH
IN
METERS
FIG P-7
DENSITY ^T
WESTERN SECTION
PONCE
CRUISE I JUNE 3 1971
0 0.5
li.il
NAUT. Mi.
6. 98
-------
60
80
100
120
~ I4O
160-
180
200
220
DEPTH IN
METERS
FIG P-8
DENSITY ^T
EASTERN SECTION
PONCE
CRUISE 2
27 SEPTEMBER 1971
-------
PLAYA DE PONCE
2M
5 ,
FIG P-9
WATER TRANSPARENCY
PONCE SITE
SECCHI DISC READINGS IN METERS
CRUISE I 3 JUNE 1971
0
L
0 5
_J
NAUT Ml
6.100 9-
-------
PLAYA DE PONCE
15
24
FIG P - 10
WATER TRANSPARENCY
PONCE SITE
SECCHI DISC READINGS IN METERS
CRUISE 2 27 SEPTEMBER 1971
0.5
NAUT Ml
23
6 . 1 0 ]
-------
GUAYANILLA
Description of Study Area
The Guayanilla-Yauco area is situated on the south coast of Puerto
Rico, about one-third of the length of the island from the western end.
The area receives freshwater inflows from Rio Yauco and Rio Guayanilla.
The river basins include portions of the rainy west central mountains,
the semi-arid southern foothills, and the dry southern coastal lowlands.
Major industries in the area include sugar processing mills at Central
San Francisco and Rufina (though the mill at Rufina is reported to have
stopped operating in 1968), and large petrochemical refineries. There
are also light manufacturing industries located mostly in Yauco. Commercial
fishing and dairy farming are carried out on a small scale in the area. Of
the three disposal sites studied on the south coast of Puerto Rico, namely
Guayama, Ponce, and Guayanilla, the water is deeper than 50 meters within
two miles offshore of the proposed treatment plant only at Guayanilla.
Hydr odynamic s
Three current surveys were carried out at Guayanilla in the vicinity
of the submerged canyon that approaches the coast just east of Punta Ventana.
Station locations for each survey are shown in Figure G&-1. An Ekman-Merz
current meter was used during Cruise 1, drogues during Cruise 2, and the
three relatively recently acquired in-situ recording current meters during
Cruise 3.
As happened with the Ekman-Merz meter at other sites on the south coast,
many of the measurements made with this instrument at Guayanilla during
6.102
-------
Cruise 1 showed bi-modal currents. Average speeds x-/ere similar at the
three depths at which readings were taken, being 0.38, 0.34, and 0.35
knots at depths of 4, 12, and 24 meters respectively. There was no
apparent correlation between velocity and the presence or absence of bi-
modal currents. As has been done in other cases involving bi-modal read-
ings, both the single mode and bi-modal (if present) directions are given
in tabular form in Appendix H. Single mode vectors are plotted in Figure
GN-2. Like other sites on the south coast, the tides at Guanica, some ten
miles west of Guayanilla, are listed in the Tide Tables as being chiefly
diurnal, and Galveston, Texas, is the reference station for which time and
height corrections are given. As stated elsewhere in this report, verifi-
cation of tide predictions for locations on the south coast computed
from the values given in the Tide Tables is to be desired. It is with
this reservation that the times of high and low x^ater at Guanica, as computed
from the Tide Tables, are used in x^hat follows as an approximation of the
times of high and low water in the region of Guayanilla.
The observations covered the last 5.5 hours of the falling tide and
the first 4 hours of the rising tide. This \
-------
strength it began to move the surface water inshore, and as this built
up, a compensatory current developed below the surface to relieve the
pressure. This, however, does not explain the curious shift to the
north which occurred only in the deeper (24 meters) water between 1430 and
1540. Figure GU-3 is another presentation of the same data, where the
length of each vector is proportional to the actual resultant net flow at
each depth over the entire period of observation, and the numerical aver-
age speed regardless of direction is also given for each depth (see
Appendix B).
During Cruise 2 drogues were used at depths of 1 and 5 meters. Re-
sults, as shown in Figure Gn-4, show average speeds of 0.22 and 0.09 knots
for the shallower and deeper drogues, respectively, with a general north-
westerly movement, approaching shore obliquely (see Appendix H). Un-
fortunately, no drogues were used at depths greater than five meters be-
cause of the likelihood of deeper drogues running aground. Thus, it is not
known whether the shear which had previously been observed at depths between
4 and 12 meters was again present.
Guayanilla was the last site occupied during Cruise 3 prior to the
writing of this report. The three Hydro Products model 502 in-situ
recording current meters were used. One meter was placed close to Punta
Ventana in 7.5 fathoms of water, with the sensor at a depth of slightly
under 7 fathoms. The two other meters were placed a few feet from one
another in precisely 25 fathoms of water, with one sensor at 6.5 fathoms
and the other at 17 fathoms, about 1.25 miles SR of Punta Ventana.
These station locations are shown in Figure GN-1. A series of developments,
6.104
-------
including rough seas, mechanical difficulties with the vessel, and
finally failure of the pop-up marker buoys to surface at the outer station,
caused a delay in retrieval of the two deeper instruments until February 8
when they were recovered by divers in approximately 35 fathoms of water.
The ocean bottom in this immediate vicinity drops from a depth of approx-
imately 19 fathoms to 150 fathoms x^ithin a horizontal distance of about
550 meters, and the anchors of the current meters had slipped 10 fathoms
down the side of the "hill1', making it impossible for the marker buoys to
reach the surface. What had been intended as the outer shallow instrument
had dropped to 17 fathoms, the depth intended for the outer deep meter.
The other instrument, retrieved at a depth of about 27 fathoms, failed to
record any data because of a minor malfunction in the chart paper transport
mechanism of the Rustrak recorder.
Graphs of results obtained with the inner shallow and what ended up
as the outer deep meter are shown in Figure Gn-5. Comparison of directional
variations at the outer deep meter with predicted times of high and low
water seems to indicate a tendency for the current to flow towards the west
near times of low tide, and for a north-easterly flow to occur near times
of high tide. In general, the registered speeds were low, rarely reaching
0.3 knot at either station. There was no noticeable correlation between
tides and either current direction or current speed at the inner shallow
station. Tabulated data is given in Appendix H.
Results of an analysis of the data are illustrated in Figure Gn-6.
6.105
-------
Here the length of each vector is proportional to the total quantity of
water which flowed in each indicated direction, and the resultant (labeled
R in the figure) shows the magnitude and direction of the net total flow
over the entire period of observation. Average speed (labeled v) of current
in each direction is given, and the percent of total time during which flow
was in the indicated direction is also given. It is to be noted that these
average speeds are not the same as the numerical average speeds given in
resultant net flow diagrams, such as Figure Gn-3, illustrating results of
a similar analysis of data from the Ekman-Merz current meter used during
Cruise 1. In the case of the Ekman-Merz data analysis only resultant
vectors are shown and the average speeds given are simply numerical
averages without regard to direction. The corresponding numerical average
speed values for the in-situ recording meters at Guayanilla are 0.19 knot
for the inner shallow meter, and 0.13 knot for the outer deep meter. A
more detailed description of the methods of analysis employed here is given
in Appendix B.
As is clear from Figure Gn-6, the current at the outer station at
Guayanilla flowed either towards the north-east or south-west for nearly
60 percent of the total period of observation. It is also apparent from
the figure that no such reversal occurred at the inner station. Unfortunately,
it was again impossible to determine x^hether the shear between shallow and
deeper water which was observed during Cruise 1 was present at the outer
station during Cruise 3.
Perhaps it is worth emphasizing that the information displayed in
6.106
-------
Figures Gn-5 and Gn-6 represents a summary of virtually continuous data
acquisition at two stations over a period of 118 hours, and is therefore
much more significant than data collected over a period of only a few
hours. The conclusions which an investigator might draw from observations
made at the outer station at Guayanilla during the daylight hours of
January 29th, for example, would differ markedly from conclusions he might
arrive at from similar observations on January 31st, as can be seen at
a glance in Figure Gn-5.
Host of the near-shore current studies along the coasts of Puerto Rico
have been of very brief duration. The comparatively long-term current
measurements made, at Guayanilla during Cruise 3 covered a period of about
one-sixth of a lunar month, starting at about the time of full moon and
spring tides on Jauary 30. It is hoped that in the future it will be
possible to collect data over a full lunar month, and simultaneously to
obtain tidal and meteorological data, which is perhaps a reasonable
minimum for a realistic evaluation of the current structure in a given area.
RydrographicData
Hydrographic station locations at the Guayanilla site are shown in
Figure Gn-7. Data obtained at these stations during Cruise 1 and 2 is
given in tabular form in Appendix F. The inner part of Bahia de Guayanilla
is roughly one degree warmer than the water outside the bay at all levels.
Flushing of the bay must be extremely limited for this gradient to be
maintained. A tongue of relatively cool water appears to coincide with the
depression in the bottom just east of Punta Ventana, indicating that cooler
6.107
-------
offshore water flows shoreward along the. depression. The surface salinity
pattern similarly shows a tongue of more saline offshore water coinciding
with the bathymetric depression. Salinity values in the inner bay are higher
than those immediately outside. It may be that this area of limited flushing
acts as an evaporation basin, thus raising the surface salinity. Horizontal
patterns of salinity at depths of 5, 10, and 30 meters are more or less
similar to the pattern at the surface, with only slight salinity changes at
any given depth. Horizontal density gradients are also generally slight,
as can be seen for surface waters in Figures Gn-8 and Gn-9. Density profiles
are shown in Figures Gn-10 and Gn-11. As can be seen from these figures,
density changes from the surface to a depth of 50 meters were found to be
less than about 0.5 sigma-t units during both cruises.
Uater Quality Data
The data collected for a water quality survey of the Guayanilla area is
given in tabular form in Appendix II. Secchi disc readings showed very low
water transparency values, as is illustrated in Figures GJt-12, Gn-13, indi-
cating extreme turbidity.
During Cruise 1 measured silica and phosphorus levels were very low,
varying from 0.0 to 0.2 mg/1 for silica and from 0.00 to 0.02 mg/1 for
phosphorus. Dissolved oxygen concentrations varied between 5.29 and 7.00
mg/1, with values around 6.5 mg/1 being typical for most of the area. Silica
concentrations were found to be a little higher, and phosphorus values a
little lower, during Cruise 2. Coliform ItPN values varied between 20 and
250/100 ml at four stations where measurements were carried out.
6.108
-------
GUAYAfMILLA
o
10
f\
X
PUNTA
VENTANA
\RIO
TALLABOA
s?
cv
PUNTA VERRACO
CURRENT WET
CRUISE 3
£y>CAYO RIO
CAYO PALOMAS
n°>
I \ 0CAYO CARIBE
\
CURRENT METER
CRUISE I
PUNTA
:^
10 FM. -
_ -* *s ~
^-
100 FM
4-
NAUT MILE
FIG GN-I
CURRENT STATION LOCATIONS
GUAYANILLA SITE
-------
MID-DEPTH
I2M
10 20 Cm/Sec 40 50
i i . i.i , i
1/4
l/2Knot 3/4
DEEP 24M
TIME 06 07 08 09 10 II
12 13 14 15 16 17
Wind: ESE
Speed 9 9 15
in Knots
14 14
15 16 14 14
18
HIGH TIDE 9 JUNE 2303
LOW TIDE IOJUNE 1252
HIGH TIDE IOJUNE 2351
WATER DEPTH 33 M-
FIG GN- 2
CURRENT VECTORS
GUAYANILLA
CRUISE I - 10 JUNE 1971
-------
PUERTO DE GUAYANILLA
.O
7/7777
CERRO
TORO
PUNTA VENTANA
V-0-38
0.5
NAUT. MILE
FIG GN-3
RESULTANT NET FLOW VECTORS
AT DEPTH OF 4,12 AND 24 METERS
CRUISE I 10 JUNE 1971
GUAYANILLA SITE
TOTAL TIME OF OBSERVATION FOR
EACH RESULTANT ABOUT 9 HOURS
DEPTH OF WATER_25 METERS
AVERAGE SPEED (V) IN Kn
6.111
-------
Fl G- GN-4
CLIRRENT DROGUES
GUAYANILLA SITE
2nd CRUISE
SERIES 1-2
SE PTEMBER 29,1 971
ON FIGURE SJ-3
1019
MILES
) 0
AA
SURFACE I M'
MID DEPTH 5
1025
SERIES I
-------
PAGE NOT
AVAILABLE
DIGITALLY
-------
PTA.
VENTANA tf
V= 0.16
45.2%T
V = 0.19
0
L
0-5
SENSOR AT I3M
BOTTOM DEPTH ISM
TOTAL TIME 116 HOURS
V= 0-13
0. 8 % T
SENSOR AT 33 M
BOTTOM DEPTH 69M
TOTAL TIME 118 HOURS
V=0'08
14-0 % T
NAUT. MILE
V=0-15
22.1% T
V= 0. 17
36-5 % T
FIG GN-6
NET FLOW CURRENT VECTORS
CRUISE 3 28JAN-2 FEB 1972
SUAYANILLA
AVERAGE SPEED (V) IN Kn
AND PERCENT OF TOTAL
TIME SHOWN FOR EACH OCTANT
-------
.PENUELAS....89.
**.
***...YAUCO.
.**...GUAYANILLA.
7*
1*
8*
2*
9* 3*
10*
5* 11*
18*
17*
16* ..
15*
14*
12*
13*
NAUT MILE
Figure GN-7a
HYDROGRAPHIC STATION LOCATIONS
GUAYANILLA
CRUISE 1 9, 10 JUNE 1971
6.115
-------
en.
.PENUELAS....88.
**.
, Ill
t * * *****YAUCO«
.IB
.
.**...GUAYANILLA.
14X
11X
12X
10X
9X
8X
15X
16X
17X
13X
IX
2X
3X
5X
7X
6X
NAUT MILE
Figure GN-7b
HYDROGRAPHIC STATION LOCATIONS
GUAYANILLA
CRUISE 2 4 OCTOBER 1971
6.116
-------
YAUCO
5UAYANILLA
PENUELAS
22.9
23.0
0
L
NAUT MILE
FIG GN-8
SURFACE DENSITY
GUAYANILLA SITE
CRUISE 1 9 JUNE I97I.
I
-------
PEfiUELAS
YAUCO
: GUAYANILLA
0
L_
NAUT MILE
FIG. GN-9
SURFACE DENSITY
GUAYANILLA SITE
CRUISE 2 4 OCTOBER 1971
6.118
-------
STA. 4t= I
SURF CPf 23.07
-I 20
-140
-160
DEPTH IN METERS
0
L_
0.5
NAUT Ml
FIG GN-IO
DENSITY
CENTRAL SECTION
GUAYANILLA SITE
CRUISE I 9JUNE 1971
-------
40-
60-
80-
100-
120-
I4O-
160-
180-
2OO-
22O-
240-
280 -*
DEPTH IN METERS
FIS GN-II
DENSITY 4t
CENTRAL SECTION
6UAYANILLA SITE
CRUISE Z
4 OCT- 1971
0.5
i i i i
NAUT MILE
22.00
22.50
23-00
23-50
24-00
7 24.50
-25-00
25-50
»26.00
6. 12H
-------
PENUELAS
IGUAYANILLA
NAUT- Ml.
9 '9
FIG GN-12
WATER TRANSPARENCY
SUAYANILLA SITE
SECCHI DISC READINGS IN METERS
CRUISE I 9 JUNE 1971
0.121
-------
YAUCO
:GUAYANILLA
PENUELAS
FIG GN-13
WATER TRANSPARENCY
GOAYANILLA SITE
SECCHI DISC READINGS IN METERS
CRUISE 2 4 OCT 1971
NAUT MILES
6.122
-------
Mayaguez
Description of Study Area
Mayaguez Bay, one of the three leading ports of Puerto Rico, is located
approximately in the middle of the west coast of the island. Depths in the
northern part of the bay run to 60 ft, but the southern part is mostly shoal.
The bay extends from Punta Guanajibo in the south to Punta Algarrobo located
one mile northeast of the shipping terminal. The freshwater contribution to
Mayaguez Bay is almost entirely from the Rio Guanajibo in the south and the
Rio Yaguez in the north. At times there is no discharge from the Rio Yaguez (1) .
A recent survey conducted by the Aqueduct and Sewer Authority indicated
that there are 161 industries in Mayaguez, 115 of which discharge wastewater
into the sanitary sewage systems of the city (1). Industrial wastes reach
Mayaguez Bay directly and indirectly via the Yaguez and Guanajibo Rivers.
Industries discharging wastes directly into the bay are centered in the area
north of the Government Wharf (2). These include three tuna canning plants
and a cattlefeed producing plant. The Rio Guanajibo brings into the bay the
wastes from Central Eureka and the effluents from a number of industries
located in the Mayaguez Free Trade Zone (2). The Yaguez River picks up the
wastes from India Brewery and from a number of small industrial plants as it
passes through Mayaguez, and finally discharges them into the bay.
Mayaguez has a population of 86,000. Approximately 43% of the population
is connected to sewers feeding a submerged, 48-inch, open-ended outfall which
discharges approximately 3000 feet from shore into about 20 feet of water.
An estimated 3.74 million gallons of untreated sewage is discharged into Mayaguez
Bay daily through this pipe.
6.123
-------
Hydrodynamic Data
The Mayapuez area is characterized by a wind pattern which is different
from that of other regions of the island (3). The sea breeze acts in an
almost opposite direction from that of the easterly trades, lessening the
strength of the trades and frequently becoming dominant, resulting in an
on-shore westerly wind. This is an area of well developed tidal currents.
The Tidal Current Tables (4) show that at a place 1.5 miles west of Punta
Ostiones (which is roughly 8 miles south along the coast from Mayaguez) the
flood tide produces a southward flowing current with an average speed of
1 knot. The ebb tide produces a northward flox^ing current with an average
speed of 0.9 knot. Previous current studies by Munoz, Nazario, et al (2)
describe a reversing cycle with a period of 5.75 hours and an average speed
of 0.38 knot. The usual path of the current is parallel to shore, according
to results of this study. However most of these observations were made in a
limited period of time and the way the data is presented does not provide the
information required for any further analysis. Guzman (1) made a study of
currents between Punta Guanajibo and the mouth of Rio de Anasco. His drogue
data showed an offshore/on-shore flow pattern. Guzman made a more extensive
study with in-situ current meters. Station locations for this study are given
in Figure M-l. Direct on-shore current flows were observed for 17.2 percent
of the time. A reversing cycle with a period of about 2.5 hours was observed.
Another current study was carried out by Colon (5) using in-situ current meters.
Figure M-l also shows the station location for this study. Tidal effects were
apparent, but the current during flood tide was towards the northeast and to
the southwest during ebb, which is roughly opposite from the corresponding
directions given in the Tidal Current Tables for the area near Punta Ostiones.
Two current surveys were carried out at Mayaguez by the Oceanographic
Project. Station locations are given in Figure M-l. The results of the
6.124
-------
current studies are given in Figures M-2 through M~4, and in Appendix I,
Measurements were made at depths of 4, 12, and 24 meters with an Ekman-Merz
current meter during Cruise 1. Figure M-2 shows velocity vectors giving the
result of each individual measurement, while Figure M-3 illustrates the
direction of the resultant net flow at each depth together with the numerical
value of average speed (regardless of direction) at that depth (see Appendix B).
Results of the drogue studies carried out during Cruise 2 are illustrated
in Figure M-A. As can be seen from the figure, the general pattern of flow
is roughly parallel to shore, with a slow trend towards shore. The highest
speeds measured with the drogues were considerably higher than maximum values
obtained x^ith the Ekman-Merz meter during Cruise 1. This may well be due
to the fact that Cruise 1 measurements were made close to the time of neap
tides, while the Cruise 2 measurements were made near the time of spring tides.
The drogue results agree roughly with predictions from the Tidal Currents
Tables, which predict southerly currents off Punta Ostiones during flood tide,
and northerly currents during the ebb.
Hydrographic Data
Locations of the hydrographic stations are shown in Figure M-5. Temperature
and salinity data is given in Appendix I. A slightly cooler ban of water is
present inshore along the coast of Bahia de Afiasco extending at least as far
as Punta Cadena. This may represent a minor upwelling brought about by local
winds pushing a thin surface layer offshore and bringing up deeper slightly
cooler water close to shore. The greatest range of surface temperature over
the entire survey area was slightly more than half a. degree. Surface salinity
values were fairly constant over the study area during both cruises, though
changes of 1-2% were observed to have occurred during the time interval between
the two studies. The U.S. Geological Study has indicated an interest in documenting
6.125
-------
the presence of freshwater springs erupting from the ocean floor on the
west coast of Puerto Rico. No evidence of such springs was found during
these two studies at Ifovapjuez. Surface density contours, computed from
measured values of temperature and salinity, are shown in Figures M-6 and
11-7. Density profiles are shown in Figures 11-8 and 31-9.
Water Quality
Water quality in the Ilayaguez area was surveyed during Cruises 1 and 2.
Data obtained during these cruises is presented in Appendix I. Only five
Secchi disc readings were taken during the first cruise, after which the
disc was lost. These readings varied between 6 and 79 meters. Dissolved
oxygen concentrations varied between 4.29 and 5.17 mg/1. BOD concentrations
and coliform MPN levels were determined from samples taken at selected
stations. BOD levels ranged from O.OQ to 1.37 mg/1, and coliform MPN levels
were from 0 to 576/100 ml. Levels of silica and phosphorus were low, both
varying between 0.0 and 0.1 mg/1.
During Cruise 2, Secchi disc readings were from 8 to 23 meters. Silica
and phosphorus levels were low, ranging from 0.04 to 0.33 mg/1 and 0.007
to 0.019 mg/1, respectively. Coliform MPN levels were slightly lower than
values observed during Cruise 1, varying from 0 to 240/100 ml.
6.126
-------
100 FM
IOFM
/"~
RIO GRANDE DE ANASCO
C
\
!
/ CURRENT METER|
I CRUISE 2^1,
I
/
s ,.
I
\
y
PUNTA ALGARROBO
' CURRENT METER
/ (GUZMAN) \
/ /"^x f
<- ' \
\ V
\^x
W.R.R.I.
FIG M-l (COLONiA."
CURRENT STATION LOCATIONS
MAYAGUEZ SITE
K
CURRENT METER
MAYAGUEZ
_i_
2Mi.
NAUT MiLE
GUANAJIBO
RIO GUANAJIBO
-------
SHALLOW 4M
HIGH TIDE
MID DEPTH 12 M LOW TIDE
HIGH TIDE
TIME
l i I
0700 08OO 0900
1000
1100
1200
1300
1400
1500 1600
1700
WIND
RISING TIDE
FALLING TIDE
0
l
10
L
20
l
30
I
40 CM/SEC
FIG M-2
CURRENT VECTORS
MAYAGUEZ
CRUISE I I7JUNE 1971
WATER DEPTH 20M
LOW TIDE 0918
HIGH TIDE 1616
6.128
-------
N
2
J
NAUT MILES
RIO GRANDE DE ANASC
FIG M-3
RESULTANT NET FLOW VECTORS AT DEPTH OF 4,12
CRUISE 1, 17 JUNE I97I
MAYAGUEZ SITE
TOTAL TIME OF OBSERVATION FOR EACH RESULTANT ABOUT
9 HOURS
DEPTH OF WATER 28 METERS
AVERAGE SPEED (V) IN Kn
RIO GUANAJIBO
-------
RIO GRANDE DE ANASCO
SEE NOTE ON FIGURE SJ-3
I3IO SERIES 2
SURFACE
MID DEPTH IOM
p D DEEP 20M
1250
1420
7> 1630
MUNICIPIO
DE
MAYAGUEZ
FIG. M-4
CURRENT DROGUES
MAYAGUEZ SITE
CRUISE 2
OCTOBER 6 1971
SERIES 1-2
1545
NAUT MILE
-------
1*
2*
3*
7*
5*
6*
21*
20*
22*
23*
8*
9*
25*
10*
19*
11*
12*
13*
IS
17*
16*
15*
* 14
....B«BB.l!«BK)*....*......*. .
.#.**.*.** MAYAGUEZ,
NAUT MILE
Figure M-5a
HYDROGRAPHIC STATION LOCATIONS
MAYAGUEZ
CRUISE 1 16, 17 JUNE 1971
6.131
-------
20X
19X
18X
13X
15X
16X
21X
17X
22X
12X
23X
24X
11X
10X
25X
9X
8X
7X
IX
2X
3X
5X
6X
NAUT MILE
.K.BB.S.BS... .
.a.ii.a.at
.*.**.*.**...,
.MAYAGUEZ.
Figure M-5b
HYDROGRAPHIC STATION LOCATIONS
MAYAGUEZ
CRUISE 2 7 OCTOBER 1971
6.132
-------
MAYAGUEZ
FIG M-6
SURFACE DENSITY AT
MAYAGUEZ SITE
CRUISE I 16 JUNE 1971
b. 135
-------
MAYAGUEZ
NAUT MILE
FIG M-7
SURFACE DENSITY AT
MAYAGUEZ SITE
CRUISE 2 70CTOBER 1971
-------
STA #
SURFACE GT
20 -
40 -
60 -
80 -
(00 -
120
I 40 -
I 60 -
80 -
200 -
220 -
240 -
DEP TH-
IN
METERS
FIG M-8
DENSITY GT MAYAGUEZ SITE
CRUISE I
16 JUNE 1971
0.5 NAUT Ml
-------
FIG M-9
DENSITY 6t
MAfAGUEZ
CRUISE 2 OCT 7 1971
-100
-------
20 -
40 -
60 -
80 -
(00 -
^"120 -
I 40 -
I 60 -
80 -
200 -
220 -
240 -
DEPTH'
IN
METERS
FIG M-8
DENSITY GT MAYAGUEZ SITE
CRUISE I
16 JUNE 1971
0-5 NAUT Ml
-------
FIG M-9
DENSITY £t
MAfAGUEZ
CRUISE 2 OCT 7 1971
20
40
-60
-80
100
120
-------
20 -
40 -
60 -
80 -
100 -
120 -
I 40 -
I 60 -
80 -
200 -
220 -
240 -
DEPTH'
IN
METERS
FIG M-8
DENSITY GT MAYAGUEZ SITE
CRUISE I
16 JUNE 1971
O-5 NAUT Ml
i
-------
FIG M-9
DENSITY 6t
M/VAGUEZ
CRUISE 2 OCT 7 1971
22
22-83
_L
23
21-85
24
21.72
25
21-76
. 22
-6
-20
-40
60
-80
100
120
160
-------
AGUADILLA
Description of Study Area
Aguadilla is situated near the northern extremity of the west coast of
Puerto Rico, facing Mona Passage to the west. The central urban area occupies
a narrow coastal zone bounded by Aguadilla Bay to the west and by mountains
to the east. Aguadilla Bay extends from about seven miles northeast of Punta
Higuero, the westernmost point of Puerto Rico, to Punta Borinquen, the north-
west corner of the island. There are no coral reefs in the bay to dissipate
wave action (1).
The Rio Culebrinos drains into Aguadilla Bay just south of the city of
Aguadilla, and is the only major stream discharging into the bay. Like so
many of the rivers in Puerto Rico, the Culebrinos undergoes enormous changes
of flow in short periods of time (3). Fifty percent of the time the flow
amounts to 77.5 IIGD or less. The river flow is less than 30 MGD about 10
percent of the time and is more than 90 MGD 10 percent of the time. A peak
of 19,122 MGD was reached during a flood on the 27th of November 1968.
Rainstorms over the watershed introduce large amounts of silt l&den water
into the coastal waters. During periods of relative calm the less-dense waters
of low salinity maintain their identity as distinct surface layers of high tur-
bidity as far as eight miles from the mouth of the river. However, rapid mixing
occurs near the mouth of the river during periods of high wave and breaker ac-
tivity (2).
The large watershed drained by the Rio Culebrinos includes the towns of
Lares, San Sebastian, Moca and Aguada. From each of these towns the Rio Cule-
brinos receives the effluent of municipal sewage treatment plants. The Central
Plata sugar mill in San Sebastian uses river water in its operations and
6.137
-------
discharges both process wastes and cooling water directly to the river. The
Central Coloso, 2.5 miles northeast of Aguada, also uses river water and dis-
charges process wastes and cooling water to a swampy area from which most of
the effluents eventually return to the river (2). Raw sewage also enters
Aguadilla Bay from four short outfalls which extend about 30-50 feet into the
bay. There are many breaks along the length of these pipes which result in
the discharge of wastewaters to the surf-zone.
Hydrodynamics
The general westward flow of the North Equatorial Current has been identi-
fied by Lowman (5) as a factor creating a clockwise gyre in Aguadilla Bay. If
this is indeed the case, then important seasonal changes caused by modifications
of the far offshore general current patterns are to be expected. The Pilot
Charts state that in March the prevailing current in Mona Passage is toward the
northwest (from Caribbean Sea into Atlantic Ocean) , while it is towards the
southwest (from the Atlantic into the Caribbean) in June. Drogue studies carried
out by Weston et al (6) showed a parallel-to-shore (SW or ME) flow, or offshore
(westerly) flow at Aguadilla. In only a few cases was an onshore current ob-
served. The clockwise gyral was present at times, but it was not always
observable. On various occasions a flow apparently associated with tidal re-
versal was observed.
Two current surveys were carried out at Aguadilla by the Oceanographic Pro-
ject. Station locations for the two cruises are shown in Figure Ag-1. Results
obtained with the Ekman-llerz meter during the first cruise are shown in Figures
Ag-2 and Ag-3, and further data is included in Appendix J. As may be seen in
Figure Ag-2, results showed a reversal from SW to roughly NE during ebb tide.
The maximum current speed occurred during the time of SW flow, at approximately
6.138
-------
the time of high tide, when it reached a. speed of about 0.8 knot. The current
pattern was very much the same from the surface to a depth of 24 meters during
the entire nine hour period of observation. Calculated average speeds during
this period were about 0.36 knot at the surface, 0.33 knot at a depth of 12
meters, and 0.30 knot at 24 meters. Figure Ag-3 shows the results of an ana-
lysis which gives an. indication of relative amounts of flow at the three depths.
The length of each resultant is proportional to the net flow (or transport) in
the direction indicated. A discussion of the method used to compute these va-
lues is included in Appendix B.
Drogue results for Cruise 2 are shown in Figure Ag-4, and additional data
is given in Appendix J. Most of the period of observation fell within the pe-
riod of ebb tide. The flow indicated by the drogues was generally to the NE,
veering towards the west after low tide. Speeds at all depths were slightly
lower than the values obtained during Cruise 1. As explained elsewhere in
this report, an in-situ recording current meter was used in addition to drogues
during Cruise 2, but the results obtained with this instrument are considered
unreliable and have therefore been omitted. In the particular case of Aguadilla,
however, the recording current meter did yield results more-or-less in agree-
ment with the drogue data, especially as regards current direction.
Judging from the data obtained during the tx^o cruises, it appears that the
water mass at Aguadilla behaves as a vertical unit, changing speed and direc-
tion approximately simultaneously from the surface to at least 20 meters. The
current is usually (but not always) roughly parallel to the shoreline, with a
tendency to flow towards the south-west during flood tide, and towards the north-
east during ebb tide. Current speeds are sometimes relatively high. A summary
of wind data obtained from Ramev Air Force Base covering the years from 1940 to
1967 is given in Appendix J. The wind is generally from the ENE, E, or ESE.
6.139
-------
As Aguadilla Bay is protected from easterly winds, wind speeds are probably consi-
derably lower in the bay than at Ramey. This view is supported by field measure-
ments by Weston et al (6). Accordingly, wind is not likely to play an important
role in the current structure at Aguadilla.
Hydrographies
The hydrographic station locations for Cruises 1 and 2 are presented in Fi-
gure Ag-5. Hydrographic data is given in Appendix J, and in Figures Ag-6 through
Ag-9. The discharge from the Rio Culebrinos causes the surface receiving water in
the vicinity of the. river mouth to be more than 0.5°C warmer than the rest of the
bay. Due to the reversal of current flow in this bay with each tidal cycle, the
direction of flow of the tongue of the river may vary. The temperature gradient
in the upper layers is relatively weak. Surface salinity values (see Appendix J)
indicate that the area of relatively fresh water x^est of the river mouth is attri-
butable to river runoff. The change in salinity is about one part per thousand.
Vertical salinity profiles are included in Appendix J. The salinity gradient in
the upper layers is somex^hat more pronounced than is the temperature gradient,
The horizontal density distribution in the surface waters at Aguadilla is
shown in Figures Ag-6 and Ag-7. As would be expected, the areas of low salinity
also shox
-------
of Aguadilla Bay are relatively homogeneous below the surface layer.
Water Quality
The assessment of water quality for this area included two cruises
which measured Secchi disc depths, dissolved oxygen, coliforms, silica, and
phosphorus. The data collected is presented in tabular form in Appendix J.,
The main feature of the Secchi depths on the first cruise was the
observation of the tongue of turbidity projecting into the ocean from Rio
Culebrinos as may be seen in Figure Ag-10. Many of the towns on the river
dump wastes into this stream or its tributaries, and these materials are
eventually transported in the stream to the ocean. The levels of silica
were found to be 0.2 and 0.3 mg/1, while, surprisingly, no phosphorus was
detected at the sampling stations. Coliform MPN levels varied from 1300 to
1600/100 ml range, reflecting the presence of adjacent waste water dis-
charges. The dissolved oxygen concentration averaged about 5 mg/1.
On the second cruise, the Secchi readings showed an eastward shift of
the end of the tongue of turbidity from the mouth of the Rio Culebrinos, as
seen from values given in Figure Ag-11. The dissolved oxygen concentrations
varied from 6.34 to 8.85 mg/1, which is significantly higher than observed
on the first cruise. Silica concentrations were between 0.08 and 0.64 mg/1,
and phosphorus levels between 0.003 and 0.051 mg/1, i.e., greater than from
the first cruise, and possibly due to seasonal varia'-ion in the phytoplonkton
populations. The coliform MPN levels varied from 0 to 3,000/100 ml, showing
a wide variation, the high counts being associated with the turbid plume of
the Rio Culebrinos.
6.141
-------
CANAL OE
LA MONA
FIG Ag-l
CURRENT STATION LOCATIONS
A6UADILLA SITE
I
I
/ \
J \
S J
CURRENT METEF?
CRUISE 2 )
AGUADILLA
RIO CULEBRINAS
IOOFM
IOFM|
CURRENTJIETER^. »
CRUISE I
NAUT MILE
-------
SHALLOW
HIGH
TIDE
SECOND
ANCHOR ^
SET / \
LOW
TIDE
RACING TIDE
CURRENT 0 10 20 30 Cfn/sec "~
SPEED I -, 1 1 1 -
SCALE O 0.25 0-5 KTS. FALLING TIDE
MID DEPTH
LOW TIDE
HOURS 7
I
NOON
WIND
SPEED
SCALE
0
10
20 KTS.
FIG Ag-2
CURRENT VECTORS
AGUADILLA
CRUISE i JUNE 24 1971
WATER DEPTH 32 M
-------
PUNTA BORINQUEN
AGUADILLA
RIO CULEBRINAS
FIG Ag-3
RESULTANT NET FLOW VECTORS AT
DEPTH OF 4,12 AND 25 METERS
CRUISE I 24 JUNE 1971
AGUADILLA SITE
TOTAL TIME OF OBSERVATION FOR
EACH RESULTANT ABOUT 9 HOURS
DEPTH OF WATER_ 21-38 METERS
AVERAGE SPEED (V) IN Kn
PUNTA H1GUERO
-------
1707
1535
1440
FIG Ag-4
CURRENT DROGUES AT AGUADILLA SITE
SERIES 1,2 OCT 13 1971 CRUISE 2
O - O SURFACE
MID DEPTH 5
Eh- Q DEEP
SEE NOTE ON FIGURE
AGUAOILLA
NAUTICAL Miles
h
I
PAROUE DE COLON
NAUT MILE
-------
5*
0 2
NAUT MILE
.PUNTA HIGUERO.
19*
20*
21*
18*
17*
.sss
.898
..888..AGUAOILLA.
..***
14*
16*
6*
13*
15*
12*
8*
11*
7*
9*
10*
2*
1*
Figure AG-5a
HYDROGRAPHIC STATION LOCATIONS
AGUADILLA
CRUISE 1 23 JUNE 1971
6.146
-------
2X
3X
16X
17X
15X
11X
14X
7X
6X
5X
18X
19X
IX
4X
..811..AGUADILLA.
..**#
10X 13X
12X
9X
8X
0 2
NAUT MILE
.PUNTA HIGUERO.
Figure AG-5b
HYDROGRAPH1C STATION LOCATIONS
AGUADILLA
CRUISE 2 14 OCTOBER 1971
6.147
-------
PUNTA BORINQUEN
FIG Ag-6
SURFACE DENSITY AT
AGUADILLA SITE
CRUISE I 23 JUNE I 971
-------
1
2 Miles
NAUT MILE
PUNTA 80RINQUEN
AGUADILLA
FIG Ag-T
SURFACE DENSITY AT
AGUADILLA SITE
CRUISE 2 14 October 1971
-------
II STA.*
22.67 SURF i-,'-.
2 0
2 2 0 -j
240
NAUT MILE
FIG Aq-8
DENSITY i<- AGUADILLA SITE
CENTRAL SECTION
CRL?ISE I 16 JUNE 1971
h. ISO
-------
160
180
FIG Ag-9
DENSITY 6T
CENTRAL SECTION
AGUADILLA SITE
CRUISE 2
14 OCTOBER 1971
I
NAUT MILE
20O
220-
DEPTH IN METERS
6.15]
-------
PUNTA BOOUERON
On
ro
AGUADILLA
NAUT Ml
FIG Ag-!0
WATER TRANSPARENCY
AGUADILLA SITE
SECCHI DISC READINGS IN METERS
CRUISE I 23 JUNE 1971
-------
PUMTA BORINQUEN
28
FIG Ag-ll
WATER TRANSPARENCY
AGUADILLA SITE
SECCHI DISC READINGS IN METERS
CRUISE 2 14 OCTOBER 1971
PUNTA HIGUERO
-------
ARECIBO/BARCELONETA
Description o£ Study Area
The Arecibo and Barceloneta disposal sites are located adjacent to
each other on the exposed north coast of Puerto Rico and will be treated
together in this discussion. At both sites, the Island shelf is generally
about 1.5 miles wide to the 100 fathom contour. It appears that the main
problem in getting a submarine outfall to deep water x^ill not be the
distance involved, but rather the steep slope of the bottom in these areas.
At each site, a major river has a pronounced effect on the water quality.
At Arecibo, the Rio Grande de Arecibo enters the ocean about one mile west
of Punta Morillos. The Rio Tanama, a major tributary which originates in
the mountains west of Utuado and empties into the Rio Grande de Arecibo,
is harnessed for hydro-power generation purposes and provides water for the
city of Arecibo. At Barceloneta, the Rio Grande de Hanati enters the ocean
about two miles east of Punta Palmas Altas, in the vicinity of the proposed
outfall site. A smaller river which enters the Rio Grande de Manati through
a network of channels in the lowlying land adjacent to the shoreline enters
the ocean about one mile west of Punta Palmas Altas.
An industrial park has been established adjacent to Barceloneta, and
other firms are reported to have commitments to build in the area (1).
Hydrodynamics
Black, Veatch and Domenech conducted current studies for the Aqueduct
and Sewer Authority at Barceloneta prior to the present study (1). Con-
clusions of the earlier study were that non-tidal currents flow parallel
6.154
-------
to the shoreline either in an easterly or westerly direction, and that on-
shore currents may occur when the tide is turning, near the time of high
or low water, with a speed unlikely to exceed 0.1 meter/sec.
The currents at Arecibo and Barceloneta are considered together in
this report because of the proximity of the sites, and the similarity of
geographical features. Station locations for Cruise 1 and Cruise 2 are
shown in Figure Ar/B-1. Cruise 3 was interrupted on the south coast be-
fore the third circuit of the Island was completed, so no data was obtained
at these sites during Cruise 3. At the present writing, there are plans
for the completion of Cruise 3, with current measurements utilizing in-situ
recording current meters to be made at Arecibo and Barceloneta, and results
to be published at a later date. Drogue studies were carried out at each
of these sites during Cruises 1 and 2, and concurrent observations were made
with an in-situ recording current meter. Unfortunately, the instrument did
not function properly and no Cruise 2 current meter data has been included
in this report.
Station locations for the. two cruises are shown in "Figure Ar/B-1 . Re-
sults of drogue studies made during Cruise 1 are shown in Figures Ar/B-2
and Ar/B-3 for Arecibo and Barceloneta, respectively. The initial path of
the drogues at Arecibo was eastward, the path of the surface drogue shifting
to the west at about 1050, whereas the path of the drogue at 10 meters
shifted westward at around 1245. For the remainder of observations the
drogue paths were westward. The shift in direction occurred at roughly the
time of high tide. The average speed of the surface water movement was over
0.5 knots, which is a relatively high value for coastal areas. The current
6.155
-------
speed at 10 meters was slightly less (see Appendix K).
The drogue pattern for Barceloneta (one day after the. drogue obser-
vations at Arecibo) was different from that of Arecibo. An initial drift
to the west x-ms observed with an eastward shift occurring at a period be-
tween low and high tide, and a shift back to the west occurring one or two
hours after high tide. The average speed for the surface drogue was 0.4
knots. At both sites the eastward drift velocity of the surface waters was
less than that observed at a depth of 10 meters, suggesting the existence
of a wind effect on the surface flow. In both cases, the wind was from ENE,
reaching speeds of 20 knots or more (Appendix K).
The drogue data for Arecibo during Cruise 2 indicated an onshore drift
path throughout most of the observation period as can be seen in Figure Ar/B-4
The average surface velocity was 0.2 knots, which is considerably less than
was observed during the previous survey (Appendix K).
The results of the current study at Barceloneta (which was carried out
a day after the study at Arecibo) showed rather different results. The
drogues indicated an eastx^ard flow during the period of rising tide. Nearly
two hours after high tide, a shift to the west was observed as shown in
Figure Ar/B-5. The speed values were comparatively high, the average value
for the surface being 0.56 knot (Appendix K). An evaluation of the wind
data did not provide a basis for explaining the marked difference in speed
and direction observed at Arecibo and Barceloneta, since on both occasions
the wind velocity was low and from the NE or ENE (Appendix K).
The results of the present study were similar to those of Domenech, Black
6.156
-------
and Veatch (1). It was found that the current usually flows roughly parallel
to the coastline with relatively high velocities for coastal waters. An
onshore current is present on occasion. During ebb tide the flow is usually
to the west, while during flood tide it is usually to the east. The east-
ward flow of surface waters was observed to have a lower velocity than deeper
waters. This mav well be due to the effect of NE winds on the surface waters.
Caution must be used in making any broad generalization. The use of anchored
current meters for periods of time up to a full lunar month will be required
to provide a suitable data base for documenting the structure of these currents.
Hydrographic Data
Tables of hydrographic data for Arecibo and Barceloneta are given in
Appendix K. Locations of the hydrographic stations are shown in Figure Ar/B-6.
For the most part, the range of temperatures observed at the surface was very
small, having a maximum differential of about 0.5°C. Similar conditions exist
in the surface salinity, for which a maximum range of 1 percent was observed,
and in the surface density for which a maximum change of 0.8 sigma-t units
was observed. The range of values of temperature, salinity, and density is
quite small for such a wide stretch of coastal water and is indicative of
homogeneous surface waters (see Figures Ar/B-7, Ar/B-8).
Density (sigma-t) profiles for both of the areas are presented in
Figures Ar/B-9 through Ar/B-12. In the deeper x^ater (below 50 meters), the
various isotherms, isohalines, and isopycnals are somewhat shallower at Arecibo
than at Barceloneta. Above 50 meters no significant differences are noted
between the two areas. Although temperature, salinity, and density values
obtained on different days do varv somewhat, there is considerable uniformity
in the values obtained during a single sampling event.
6.157
-------
Water Quailty
The Arecibo and Barceloneta areas were also considered together for
water quality because of their adjacent coastal locations. Two cruises
were made to evaluate and comnare parameters. The data from these cruises
is presented in tabular form in Appendix K.
The transparency of the water, as measured by Secchi disc readings,
shows turbidity levels associated with the presence of runoff of the Rio
Grande de Arecibo and the Rio Grande de Manati (see Figure's Ar/B-13, Ar/B-14).
Stations x^ere not placed in the eastern section, so the shape of the Rio
Grande de Manti plume was not determined.
The dissolved oxygen concentrations varied from 4.24 to 4.51 mg/1 for
Arecibo and from 4.56 to 4.92 mg/1 for Barceloneta, both representing approx-
imately 90 percent saturation. The phosphorus and silica levels were both
low (0-0.03 mg/1 and 0-0.23 mg/1, resnectively). The MPN coliform levels
varied from 0 to 348/100 ml at Arecibo, and were not determined at Barceloneta.
The BOD levels were not measured at Arecibo and varied from 0.06 to 0.71 mg/1
at Barceloneta.
During Cruise 2, efforts were directed primarily at measurement of Secchi
depths, dissolved oxygen levels, and coliform counts. The Secchi depths
followed the same pattern as seen previously. Dissolved oxygen levels were
higher during the second'" cruise (6.6-8.4 mg/1), reflecting the change in water
temperature. Coliform levels varied from 0 to 50/100 ml at the stations where
observations were made.
6.158
-------
OCEANO ATLANTICO
100 FM
^, ^
CURRENT METER
CRUISE 2
CURRENT DROGUES
CRUJSE I AND 2
IOFM
DROGUES
CRUISE I AND 2
CURRENT METER
CRUISE2
8ARCELON-ETA
FIG Ar/B-l
CURRENT STATION LOCATIONS
ARECIBO- BARCELONETA SITE
RIO GRANDE
DE MANATI
-------
1617
1610
1420
1245
1050
SEE NOTE ON FIGURE
1615
1300
SERIES 2
1505
1305
T!T7TTTTTTrTTTTTTT
ARECIBO
NAUTICAL MILE
FIG Ar/B-2
CURRENT DROGUES AT
ARECIBO SITE
CRUISE I 12 JULY 1971
SERIES 1-2-3
0 0 SURFACE
A A-MID DEPTH IOM
Q D DEEP
-------
1407
I6IO&-
0955
SEE NOTE ON FIGURE SJ-3
0955
FIG Ar/B-3
CURRENT DROGUES - BARCELONETA
SERIES I -2-3
CRUISE I 13 JULY 1971
O ©SURFACED 2
DEPTH IOM.
0.5
NAUT MILE
-------
SEE NOTE ON FIGURE Sd-3
0-5NAUT MILE
plG Ar/B-4
CURRENT DROGUES AT ARECIBO SITE
CRUISE 2 19 OCTOBER 1971
SERIES (-3
0 SURFACE
A MID DEPTH
Q 0 DEEP
-------
16.26
SEE NOTE ON FIGURE SJ-3
°805
1114
PAL MAS
ALIAS
CURRENT DROGUES AT
BARCELONETA
CRUISE 2 20 OCTOBER 1971
SERIES 1-2
0 0 SHALLOW
A A MID DEPTH
D D DEEP 0
0.5
NAUT MILE
-------
11*
12*
10*
3*
2* 5*
1*
4* 8*
7*
6*
.III.
.I.
.***.
13*
9*
4*
3*
1*
7*
16*
15* 10*
6*
11*
12*
14*
9*
2*
5*
13*
8*
.CB.
0 2
NAUT MILES
.ARECIBO.
**.
.BARCELONETA.
Figure Ar/B-6a
HYDROGRAPHIC STATION LOCATIONS
ARECIBO-BARCELONETA
CRUISE 1 7, 8 JULY 1971
-------
5X
15X
14X
18X
15X
11X
SX
3X
18X
3X AX
10X
13X 9X
2X 7X 17X
IX 6X
14X
13X
12X
11X
10X
17X
16X
9X
12X IX
2X 5X 16X
6X
IX
7X
o- . .!!".!!.' "I.!!!!!!! I!!! 1!!!!".". 1.!..!.!.!..!
L- ....BBB o
& iai. ,.»*.
tn *** 8».
....ARECIBO **.
BARCELONETA .
0 2
NAUT MILES
Figure Ar/B-6b
HYDROGRAPHIC STATION LOCATIONS
ARECIBO-BARCELONETA
CRUISE 2 21, 27 OCTOBER 1971
-------
8 JULY
7 JULY
23.20
CT-
ARECIBO
8ARCELONETA
FIG Ar/B-7
SURFACE DENSITY AT
ARECIBO-8ARCELONETA SITES
CRUISE I 7-8 JULY 1971
2 Mile
NAUT MILE
-------
SURF (T
0 -
20 -
40 -
60 -
80 -
100 -
120 -
140 -
160
180 -
200-
0.5 NAUT Ml
FIG Ar/8-9
DENSITY
-------
STA. #
SURF. (Ft
0 -
20 -
40 -
60 -
80 -
100 -
120 -
140 -
160 -
180 -
200-
I i i
0.5 NAUT Ml
FIG Ar/B-IO
DENSITY £"t
CENTRAL SECTION
BARCELONETA SITE
CRUISE I
8 JULY 1971
220 -
-------
SURFACE
20
40-
60-
80-
100
120
140-
160-
18O
200-
220-
DEPTH
IN
METERS
25-0
FIGAr/B- II
DENSITY ^T
CENTRAL SECTION
ARECIBO SITE
CRUISE 2
26 OCTOBER 1971
0
0-5
1
NAUT. MILE
6.169
-------
SURFACE
20
40
60-
80
100
120
140
160-
180
220
FIG Ar/B-12
DENSITY »T
CENTRAL SECTION
BARCELONETA SITE!
CRUISE 2
27 OCT 1971
OEf>TH
IN
METERS
0.5
NAUT MILE
6.170
-------
7 JULY
8 JULY
22
19'
FIG Ar/8-13
WATER TRANSPARENCY
ARECIBO BARCELONETA SITES
SECCHI DISC REAOfNGS IN METERS
CRUISE I JULY 1971
BARCELONETA
IMAUT Ml
-------
26 OCT.
21 OCT
FIG Ar/B-14
WATER TRANSPARENCY
ARECIBO-BARCELONETA SITES
SECCHI DISC READINGS IN METERS
CRUISE 2 21,26,27 OCTOBER 1971
J^BARCELONETA
N
NAUT Ml
------- |