Mobile Bay
Water Quality Model Intensive Surveys Report
July 2000/May 2001
US EPA - SESD
Project #01-0546/
Project #00-0704
US EPA - SESD
980 College Station Road
Athens, GA 30605
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Table of Contents
Page
Field Survey Personnel i
List of Tables ii
List of Figures iii
Introduction 1
Study Objectives 2
Study Area 2
Survey Components/Results 4
DST Profiling 4
Tide-Phased WQ Sampling/DO Profiling 10
Continuous DO Monitoring 17
Production/Respiration 21
Diffusion/Reaeration 25
Hydrological/Meteorological Data 28
Sediment Oxygen Demand 40
Point Source Sampling 42
Conclusion 46
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Field Survey Personnel
July 2000
May 2001
EPA - SESD
EPA - SESD
Leslie Cagle
Tom Cavinder
John Deatrick
Candace Halbrook
Pete Kalla
Mark Koenig
Laura McGrath
Philip Murphy
Mel Parsons
Bob Quinn
Bill Bokey
Leslie Cagle
Tom Cavinder
John Deatrick
Candace Halbrook
Elizabeth Jones
Pete Kalla
Mark Koenig
John Marlar
Laura McGrath
Philip Murphy
Mel Parsons
Bob Quinn
Dan Thoman
EPA - WMD
Ed Decker
Bob Howard
Tom McGill
EPA - WMD
Ed Decker
Morris Flexner
Bob Howard
ADEM
Charles Reynolds - Montgomery Office
Heather Boche - Mobile Office
Nancy Shaneyfelt
Rob Turner
Eddie Wolfe
ADEM
Charles Reynolds - Montgomery Office
Heather Boche - Mobile Office
Nancy Shaneyfelt
Rob Turner
Eddie Wolfe
ESAT
Jerry Ackerman
Bruce Heinish
Roseanne Hutchison
EPA appreciates the extensive field support provided by the Alabama DEM in conducting
these surveys.
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List of Tables
No. Description Page
1. Study Components 4
2. Water Quality Sampling Stations 5
3. WQ Sampling Results - July 12, 2000 - High Slack Tide 12
4. WQ Sampling Results - July 14,2000 - Ebbing Tide 13
5. WQ Sampling Results - May 15, 2001 - High Slack Tide 14
6. WQ Sampling Results - May 16, 2001 - Low Slack Tide 15
7. Continuous Dissolved Oxygen Monitoring Summary 17
8. July 2000 Production/Respiration 21
9. May 2001 Production/Respiration 22
10. July 2000 Chlorophyll/AGPT 23
11. May 2001 Chlorophyll/AGPT 24
12. Solar Radiation 40
13. Sediment Oxygen Demand Rates 41
14. July 2000 Point Source Sampling Results 44
15. May 2001 Point Source Sampling Results 45
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List of Figures
No. Description Page
1. Mobile Bay Study Area 3
2. Water Quality Sampling Stations 6
3. July 2000 DST Profiling Locations 7
4. May 2001 DST Profiling Locations 9
5. MB3 Turbidity vs. Tide/Wind - 2001 19
6. MB4 Turbidity vs. Tide/Wind - 2001 19
7. Gas/Tracer Study Locations 26
8. 7/13/00 Reaeration Wind/Current Vectors 27
9. 7/15/00 Reaeration Wind/Current Vectors 27
10. 5/15/01 Reaeration Wind/Current Vectors 28
11. July 2000 MB 1 Currents (Oyster/Time Series Plots) 30
12. July 2000 MB3 Currents (Oyster/Time Series Plots) 31
13. July 2000 MB4 Currents (Oyster/Time Series Plots) 32
14. May 2001 MB1 Currents (Oyster/Time Series Plots) 33
15. May 2001 MB3 Currents (Oyster/Time Series Plots) 34
16. May 2001 MB4 Currents (Oyster/Time Series Plots) 35
17. May 2001 MS0 Currents (Oyster/Time Series Plots) 36
18. July 2000 Water Level - Dog River 37
19. July 2000 Water Level - Fowl River 37
20. May 2001 Water Level - Dog River 38
21. May 2001 Water Level - Fowl River 38
22. July 2000 Wind 39
23. May 2001 Wind 39
24. Point Source Locations 43
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Introduction
The Mobile River/Bay is a 303(d) listed water body with impairment resulting from
depressed dissolved oxygen (DO) levels. In addition, the State water quality criteria for DO for
the Mobile River, Chickasaw Creek, and Three Mile Creek has been disapproved by EPA. As
part of TMDL development being coordinated by EPA Region 4's Water Management Division
(WMD), the Science and Ecosystem Support Division (SESD) was requested to conduct water
quality studies of Mobile Bay designed specifically to provide instream data for use by WMD in
development and calibration/verification of a 3-dimensional time-variable water quality model.
To obtain adequate data for model calibration and verification, two intensive surveys were
conducted on Mobile Bay.
The first SESD Mobile Bay intensive water quality survey was conducted in July 2000,
followed by a second intensive survey in May 2001. By design, one survey dataset is intended to
serve as a model calibration dataset, while the other is intended for model verification. While the
2000 and 2001 intensive survey study plans are very similar with respect to the type of data
targetted, the surveys were conducted during different seasonal conditions in order to provide
comparable data across a range of conditions. In addition, dissolved oxygen, salinity and
temperature (DST) profiling during the 2001 survey was expanded to obtain more measurements
east-west along the bay. It should also be noted that WMD indicated at the outset of the project
that considerable hydrodynamic data exists for Mobile Bay and that SESD activities should be
more focussed on water quality measurements and kinetics. This report describes and
summarizes the results of the 2000 and 2001 calibration/verification surveys.
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Study Objectives
The purpose of the 2000 and 2001 intensive surveys was to provide the necessary water
quality data along with supplemental hydrodynamic information to enable calibration and
verification of a 3-dimensional, time-varying water quality model for Mobile Bay. The studies
were designed to provide water quality data, oxygen dynamics, and meteorologic data , and
limited hydrodynamic data throughout the study area including the modeled system boundaries
and several representative calibration points. In addition, the surveys were designed to provide
instream data over a range of seasonal and tidal conditions so that the calibrated model could be
applied in a predictive mode over a wide range of conditions.
Study Area
Mobile Bay is a very large bay stretching approximately 30 miles from top to bottom and
encompassing an area of approximately 400 square miles. The Mobile Bay study area includes
the entire bay from its mouth at the Mississippi Sound/Gulf northward into the Mobile River at its
confluence with Chickasaw Creek (Figure 1). The Mobile Bay study area also includes Three
Mile Creek, Chickasaw Creek, and Dog River. In addition, a headwater sampling station was
located in the Mobile River at a public boat ramp near Mt. Vernon, Alabama. Finally, in order to
aid in potential future model development or expansion, insitu water quality data was collected in
Oyster Bay, Weeks Bay, Magnolia River, and the Intracoastal Waterway.
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Figure 1 - Mobile Bay Study Area
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Survey Components/Results
The 2000 survey includes eight separate study components. For the 2001 survey,
dissolved oxygen/salinity/temperature (DST) profiling and water quality sampling were broken
into separate components (Table 1).
Table 1 - Study Components
Module
2000 Survey
2001 Survey
1
Tide-phased WQ Sampling/
DST Profiling
DST Profiling
2
Continuous DO Monitoring
Tide-phased WQ Sampling
3
Photosynthesis/Respiration
Continuous DO Monitoring
4
Diffusion
Photosynthesis/Respiration
5
Reaeration
Diffusion
6
Hy drol ogi c/Meteorol ogi c
Reaearation
7
SOD
Hy drol ogi c/Meteorol ogi c
8
Point Source Sampling
SOD
9
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Point Source Sampling
DST Profiling
In 2000, DO, salinity, and temperature (DST) profiling was conducted throughout the bay
during a 6 day period from July 11 to July 16. On July 11, preliminary profiling was conducted at
several stations in association with the deployment of other instrumentation (e.g., current meters,
stage recorders) In addition, one crew profiled the upper tributaries (Chickasaw Creek and Three
Mile Creek) and upper Ship Channel near station SCI. On July 12 and 14, profiling was
conducted by several crews in association with water quality sample collection. Water quality
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sampling station locations/crews are shown in Table 2 and Figure 2. (Due to a storm, stations
SC4, MB3, and MSO were not profiled during the July 14 sample collection.) Profiling during
these events provided information on stratification necessary for proper sampling at each of the
water quality sampling stations. The July 12 event represents a high slack tide event while the
July 14 event occurred during an ebbing tide. Also during the July 14 effort, profiling was
conducted above and below three major effluent dischargers including International Paper,
Kimberly Clark, and Mobile WWTP. The remaining profiling efforts were designed to provide
significant coverage of bay salinity and DO for use in model setup and calibration. These events
included lower bay profiling on July 13, middle bay profiling on July 15, and profiling throughout
the Ship Channel on July 16. Figure 3 shows the areal extent of DST profiling conducted in July
2000.
Table 2 - Water Quality Sampling Stations
Station
Sampling Crew
Description
Latitude
Longitude
MR1
1 - Headwater
Upstream Boundary - Mobile River
31° 05.27'
87° 58.60'
CC
2 - River/Tribs
Chickasaw Creek near mouth
30° 44.37'
88° 02.75'
TMC
2 - River/Tribs
Three Mile Creek near mouth
30° 43.62'
88° 02.92'
DR
3 - Middle Bay
Dog River near mouth
30° 34.2'
88° 05.7'
SCI
2 - River/Tribs
Mobile Ship Channel - Station 1
30° 43.0'
88° 02.5'
SC2
3 - Middle Bay
Mobile Ship Channel - Station 2
30° 36.0'
88° 02.0'
SC3
3 - Middle Bay
Mobile Ship Channel - Station 3
30° 28.8'
88° 01.0'
SC4
4 - Lower Bay
Mobile Ship Channel - Station 4
30° 22.8'
88° 01.3'
SC5
4 - Lower Bay
Mobile Ship Channel - Station 5
30° 15.5'
88° 02.3'
MB1
3 - Middle Bay
Upper Bay near Montrose
30° 36.0'
87° 58.0'
MB2
3 - Middle Bay
Middle Bay near Point Clear
30° 28.3'
87° 58.0'
MB3
4 - Lower Bay
West Bay below Fowl River
30° 22.0'
88° 04.0'
MB4
4 - Lower Bay
Bon Secour Bay
30° 19.0'
88° 53.0'
MSO
4 - Lower Bay
Mississippi Sound
30° 17.5'
88° 07.1'
GULF
4 - Lower Bay
Gulf of Mexico east of Bay inlet
30° 08.7'
88° 02.2'
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Figure 2 - Water Quality Sampling Stations
-6-
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Figure 3 - July 2000 DST Profiling Locations
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The three profiles conducted at the upstream boundary station MR1 support its suitability
as the upstream boundary sampling location. This location was consistently freshwater when
profiled with all measured DO levels greater than the 5 mg/1 EPA Fish & Wildlife DO criteria. In
general, data for all profiles showed DO above 5 mg/1 in the upper water column (depth < 3') with
significant reductions in DO with depth at many locations especially in the upper bay and
tributaries. With respect to calibration, it should be noted that the DO end check of the meter
used during the July 15 middle bay profiles indicated a DO reading above the Winkler titration
standard (+ 0.38 mg/1) slightly outside EAB tolerances for this parameter (+ 0.2 mg/1). Heating
of the DO chamber between Winkler titration and meter recording may have occurred resulting in
the difference. Since this meter was used throughout the rest of the survey period without
calibration problems and the error is relatively small versus the measured Bay DO range, SESD
believes the profiling data to be acceptable for the purposes of model development and
calibration.
In 2001, significant DST profiling was again conducted. On May 15 and 16, profiling was
again conducted in association with water quality sampling. In addition, on May 16 profiling was
conducted in Weeks Bay and the Magnolia River while Oyster Bay and the Intracoastal
Waterway were profiled on May 17. Finally, on May 17 and 18 a profiling crew conducted
profiles laterally across the bay to enhance the 3-dimensional water quality "picture" of the bay.
The locations of the May 2001 DST profiling stations are shown in Figure 4.
Again in 2001, DO at the headwater station MR1 was consistently well above 5 mg/1. DO
in the bay and tributaries again exceeded 5 mg/1 in the upper layers (3' - 6') with DO decreasing
with depth frequently below 5 mg/1. With the exception of the bottom reading at one Magnolia
River station, all DO measurements in profiles for Weeks Bay, Magnolia River, Oyster Bay, and
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Figure 4 - May 2001 DST Profiling Locations
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the Intracoastal Waterway exceeded 5 mg/1.
In addition to DO, salinity, and temperature profiling, the 2001 profiling included some
turbidity measurements. In general, the data show turbidity levels decreasing from the north end
of the bay to the bay outlet. The following calibration information should be considered during
any application of the data to a model. Specifically, the turbidity meter used by the
river/tributaries sampling team during the first water quality sampling run (5/15) read a 10.0 NTU
standard at only 8.3 NTU, while the same unit when used for the Weeks Bay/Magnolia River
profiling (5/16) read a 10.0 NTU standard as 12.6 NTU.
Tide-phased Water Quality Sampling
Water quality sampling locations for the both the 2000 and 2001 surveys are shown in
Figure 2 (p.6). Measured water quality parameters during these studies include ultimate
biological oxygen demand (BODu - 120 day test), carbonaceous 5-day biological oxygen demand
(CBOD5), dissolved phosphorus (Diss-P), total phosphorus (Tot P), total kjeldahl nitrogen
(TKN), ammonia nitrogen (NH3-N), nitrate/nitrite (N02/N03), and total organic carbon (TOC).
In addition, limited samples were collected for total suspended solids (TSS) analysis during the
2001 survey. Where pronounced stratification in either temperature, salinity, or dissolved oxygen
was observed during profiling, samples were collected in an upper layer of the water column and
a lower layer. Upper layer samples are denoted for the 2000 survey by the letter T while lower
layer samples are denoted by the letter B (eg, MB3-B). For 2001, the designators are A and B for
upper and lower layer samples, respectively. Where no stratification was observed amiddepth
sample was collected. Also, due to laboratory constraints, long-term BOD analysis was generally
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not conducted on lower layer samples. In July 2000, samples were collected for the suite of
parameters during a high slack tide period and an ebbing tide period at the stations in Table 2.
The selection of the sampling period was based in part on ensuring that holding times would not
be exceeded during transport from the Mobile area to the SESD laboratory in Athens, Georgia. In
2001, traditional slack tide sampling was employed with the first of two sampling efforts
occurring during a high slack tide and the second taking place on the following low slack tide.
The sampling results for the 2000 survey are shown in Tables 3 and 4 while results for the
2001 survey are provided in Tables 5 and 6. For both the 2000 and 2001 surveys, the BODu
values reported in Tables 3-6 represent total ultimate BOD reported by the laboratory. For the
2000 survey, CBOD5 concentrations were < 2 mg/1 for most of the stations during both events.
Slightly higher concentrations were observed in the ship channel (SC2 & SC4). For the 2001
survey, CBOD5 concentrations were again generally below 2 mg/1 with all stations below 3 mg/1.
In 2000, only limited TOC sampling was conducted and then only for the high slack event.
Results of this limited sampling showed a maximum TOC of 6.2 mg/1 at the headwater station and
a minimum concentration of 1.8 mg/1 at the downstream boundary (GULF). The remaining ten
TOC values are in a narrow range from 2.7 to 3.6 mg/1. More extensive TOC sampling was
conducted during the 2001 survey. Due to instrument malfunctions during analysis,
holding times for a few TOC samples on the low slack tide event were missed and the analytical
results flagged as estimated (See Table 6). The reported TOC data for the 2001 survey again
show little variation throughout the bay during either sampling event with concentrations slightly
lower during the low slack tide period. Nearly all ammonia and nitrate/nitrite concentrations were
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Table 3 - Water Quality Sampling Results
July 12, 2000 - High Slack Tide
Station
T ime
BODu
(mg/1)
CBOD5
(mg/1)
TOC
(mg/1)
NH3-N
(mg/1)
N02/N03
(mg/1)
TKN
(mg/1)
Tot P
(mg/1)
Diss P
(mg/1)
Samp le
Depth
(ft)
MR1
1600
7.53
2.0 UJ
6.2
0.050 U
0.050 U
0.480
0.077
0.041
10
CC
1130
5.36
2.0 UJ
3.4
0.118
0.050 U
0.540
0.710
0.020 U
7
TMC
1200
8.46
2.0 UJ
3.6
0.253
0.323
1.46 J
0.191
0.125
7
TMC (d)
1200
9.02
2.0 UJ
7
SC1T
1015
5.18
2.0 UJ
0.154 A
0.050 U
0.489 J
0.084 A
0.084 A
8
SC1B
1030
2.0 UJ
0.272
0.050 U
0.494 J
0.096
0.061 A
28
SC2
1145
23.7
6.8 J
0.050 U
0.050 U
0.714
0.090
4
SC2 (d)
1145
3.1 J
4
SC3T
0950
6.24
2.0 UJ
2.8
0.050 U
0.050 U
0.417 A
0.072
0.020 U
3
SC3T (d)
0950
6.14
3
SC3B
1000
2.0 UJ
0.050 U
0.050 U
0.398 A
0.045 A
0.046
9
DR
1230
10.8
2.0 UJ
3.6
0.050 U
0.050 U
0.506
0.064
0.0 23 A J
12
MB1
1115
8.23
2.0 UJ
3.4
0.050 U
0.050 U
0.414
0.069
6
MB2
1030
5.97
2.0 UJ
2.9 AJ
0.050 U
0.050 U
0.502
0.059
0.02 U
6
SC4T
1450
12.4
5.8 J
0.050 U
0.050 U
0.590 J
0.044
0.038
5
SC4T (d)
1450
10.9
5
SC4B
1500
3.75
2.0 UJ
0.050 U
0.050 U
0.350 J
0.043
0.029
20
SC5T
1200
5.04
2.0 UJ
2.7 AJ
0.050 U
0.050 U
0.335 J
0.0 46 AJ
0.020
5
SC5T (d)
1200
4.56
2.0 UJ
5
SC5B
1210
3.68
2.0 UJ
0.050 U
0.050 U
0.292 J
0.058
0.020 U
26
MB3T
1430
9.42
2.2 J
3.2
0.050 U
0.050 U
0.580 J
0.066
0.041
3
MB3B
1420
5.05
2.0 UJ
0.050 U
0.050 U
0.394 J
0.084
0.020 A
11
MB4
1300
5.56
2.0 UJ
2.8
0.050 U
0.050 U
0.442 J
0.077
0.059
6
MSO
1400
8.90
2.0 UJ
3.0
0.050 U
0.050 U
0.562 J
0.040
0.020 U
6
MSO (d)
1400
8.81
2.0 UJ
6
GULFT
1110
2.71
2.0 UJ
1.8
0.050 U
0.050 U
0.292 A
0.020 U
0.020 U
5
GULFB
1100
1.41
2.0 UJ
0.050 U
0.050 U
0.107
0.020 U
0.020 U
26
GULFB (d)
1100
1.35
26
A - Ave rage Value; J - Estim ated Value; U - M aterial analyzed for but no t detected (number is minimum quantitation limit); (d) - QA duplicate sample
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Table 4 - Water Quality Sampling Results
July 14, 2000 - Ebbing Tide
Station
T ime
BODu
(mg/1)
CBOD5
(mg/1)
TOC
(mg/1)
NH3-N
(mg/1)
N02/N03
(mg/1)
TKN
(mg/1)
Tot P
(mg/1)
Diss P
(mg/1)
Samp le
Depth
(ft)
MR1
1635
2.0 UJ
0.050 U
0.050 U
0.392
0.044
0.036
11
CC
1335
2.0 UJ
0.120
0.050 U
0.465 J
0.036
0.038
9
TMC
1405
2.0 UJ
0.162
0.050 U
0.503 J
0.079
0.050
8
IPU
1215
5.69
2.0 UJ
0.173
0.050 U
0.499 A
0.105
0.045
8
IPD
1240
5.98
2.0 UJ
0.155
0.050 U
0.484 J
0.151
0.071
9
KCD
1305
6.23
2.0 UJ
0.133
0.050 U
0.466 J
0.054
0.022
8
MTPU
1515
5.22
2.0 UJ
0.166
0.050 U
0.443 J
0.088
0.046
11
MTPD
1600
14.7
2.3 J
0.103
0.050 U
0.432 J
0.049
0.0 49 A J
9
SC1T
1430
5.96
2.0 UJ
0.176 A
0.050 U
0.462 J
0.0 86 A J
0.043
10
SC1T (d)
1430
5.83
10
SC1B
1435
2.0 UJ
0.294
0.050 U
0.450 J
0.072
0.049
29
SC2
1130
6.9 LJ
0.050 U
0.050 U
0.737 J
0.098
0.078
3
SC2 (d)
1130
5.0 LJ
3
SC3T
0910
5.72
2.0 UJ
0.050 U
0.050 U
0.396 J
0.076
0.057
3
SC3B
0915
2.0 UJ
0.061
0.050 U
0.435 J
0.068
0.0 56 A J
10
DRT
1230
3.5 J
0.050 U
0.050 U
0.595 J
0.073
0.064
2
DRB
1235
2.0 UJ
0.050 U
0.050 U
0.592 J
0.078 A
0.068
15
MBIT
1050
9.54
2.2 J
0.050 U
0.050 U
0.455 J
0.077
0.067
4
MB1B
1055
2.0 UJ
0.050 U
0.050 U
0.465 J
0.115
0.080
10
MB2
0940
6.03
2.0 UJ
0.050 U
0.050 U
0.409 J
0.068
0.032
6
SC4T
1610
2.0 UJ
0.050 U
0.050 U
0.396
0.033
0.046
5
SC4B
1620
2.0 UJ
0.056
0.050 U
0.396J
0.037
0.417
30
SC5T
1340
9.42
2.0 UJ
0.050 U
0.050 U
0.337 J
0.055
0.029
5
SC5B
1330
3.71
2.0 UJ
0.050 U
0.050 U
0.301
0.020 U
0.025
30
MB3T
1630
7.55
2.0 UJ
0.050 U
0.050 U
0.433
0.039
0.033
3
MB3B
1640
2.0 UJ
0.050 U
0.050 U
0.418 A
0.028
0.033
11
MB4
1415
6.72
2.0 UJ
0.050 U
0.050 U
0.487
0.0 92 AJ
0.052
5
MB4 (d)
1415
6.93
5
GULF
1245
3.75
2.0 UJ
0.050 U
0.050 U
0.286 A
0.020 U
0.020 U
5
A - Average Value; J - Estimated Value; U - Material analyzed for but not delected (number is minimum quantitation limit); (d) - QA duplicate sample;
L - Actual value known to be higherthan value given.
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Table 5 - Water Quality Sampling Results
May 15, 2001 - High Slack Tide
Station
T ime
BODu
(mg/1)
CBOD5
(mg/1)
TOC
(mg/1)
NH3-N
(mg/1)
N02/N03
(mg/1)
TKN
(mg/1)
Tot P
(mg/1)
Diss P
(mg/1)
TSS
(mg/1)
D
(ft)
MR1
1530
5.01
1.0 U
6.6
0.050 U
0.050 U
0.36
0.039
0.027
5.5
< 1
CC-A
1645
1.0 u
3.9
0.090
0.050 U
0.49
0.036
0.021
5.0
6
CC-A (d)
1645
1.0 u
4.4
0.10
0.050 U
0.41
0.034
0.020 U
6
CC-B
1650
1.0 u
4.7
0.18
0.050 U
0.31
0.058
0.048
12
20
TMC-A
1730
2.4
5.3
0.050 U
0.48
0.68
0.097
0.068
10
3
TMC-B
1735
1.0 U
4.6
0.18
0.052
0.48
0.052
0.043
9.5
11
SC1-A
1755
4.34
1.0 U
3.3
0.13
0.098
0.48
0.051
0.033
3.5
SC1-B
1800
1.0 U
4.7
0.15
0.050 U
0.41
0.077
0.035
31
SC2-A
1910
4.49
1.0 U
4.0
0.050 U
0.050 U
0.38
0.033
0.023
2
SC2-B
1920
1.2
4.3
0.063
0.050 U
0.37
0.046
0.031
16
SC3-A
1540
6.70
1.4
3.9
0.050 U
0.050 U
0.40
0.028
0.020 U
4
SC3-B
1550
1.0 UJ
4.3
0.050 U
0.050 U
0.33
0.037
0.022
13
DR
2010
1.4
3.9
0.050 U
0.050 U
0.42
0.038
0.033
11
DR (d)
2010
1.3
4.2
0.050 U
0.050 U
0.33
0.035
0.026
11
MB1 -A
1800
6.59
1.6
4.0
0.050 U
0.050 U
0.32
0.032
0.020 U
3
MB1 -B
1810
2.7
4.8
0.065
0.050 U
0.52
0.084
0.054
9
MB2 -A
1640
7.20
1.9
3.5 AJ
0.050 U
0.050 U
0.37
0.034
0.030
3
MB2-B
1650
2.2
4.7
0.050 U
0.050 U
0.52
0.070
0.063
10
SC4-A
1710
4.60
1.1
3.2 AJ
0.050 U
0.050 U
0.51
0.029
0.020 U
7
SC4-A (d)
1710
1.2
3.8
0.050 U
0.050 U
0.52
0.026
0.020 U
7
SC4-B
1715
1.0 U
4.7
0.050 U
0.050 U
0.28
0.034
0.020 U
35
SC5-A
1505
3.83
1.2
3.7
0.050 U
0.050 U
0.28
0.024
0.020 U
5
SC5-B
1510
1.0 U
4.7
0.050 U
0.050 U
0.23
0.028
0.020 U
25
MB3
1625
4.87
1.5
3.9
0.050 U
0.050 U
0.36
0.020 U
0.020 U
5
MB4
1750
2.1
4.1
0.050 U
0.050 U
0.45
0.032
0.032
3
MSO
1555
6.09
1.9 AJ
4.2
0.050 U
0.050 U
0.40
0.042
0.020 U
3
GULF-A
1435
6.93 A
1.0 U
4.7
0.050 U
0.050 U
0.12
0.020 U
0.020 U
10
GULF-B
1430
1.0 U
4.7
0.050 U
0.091
0.10 U
0.028
0.020 U
40
A - Average Value; J - Estimated Value; U - Material analyzed for but not detected (number is minimum quantitation limit); (d) - QA duplicate sample;
-14-
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Table 6 - Water Quality Sampling Results
May 16, 2001 - Low Slack Tide
Station
T ime
BODu
(mg/1)
CBOD5
(mg/1)
TOC
(mg/1)
NH3-N
(mg/1)
N02/N03
(mg/1)
TKN
(mg/1)
Tot P
(mg/1)
Diss P
(mg/1)
TSS
(mg/1)
D
(ft)
MR1
0915
6.16
1.2
6.2
0.050 U
0.050 U
0.34
0.049
0.031
10
< 1
CC-A
1100
5.03 A
1.0 U
4.1
0.11
0.077
0.50
0.044
0.030
10
9
CC-B
1105
1.0 UJ
3.7
0.28
0.050 U
0.49
0.057
0.046
22
25
TMC-A
1015
7.98 A
1.3
2.8 J*
0.11
0.74
0.61
0.15
0.110
9.0
4.5
TMC-A (d)
1015
1.3
3.0 J*
0.11
0.72
0.61
0.14
0.091
12
4.5
TMC-B
1025
1.0 U
1.6 J*
0.51
0.25
0.72
0.12
0.080
8.0
11
SC1-A
0945
4.64
1.0 U
4.4
0.11
0.059
0.38
0.043
0.033
6.5
SC1-B
0800
1.0 U
2.8 AJ
0.24
0.050 U
0.36
0.054
0.038
35
SC2-A
0840
6.62
1.5
3.1
0.052
0.050 U
0.38
0.044
0.030
4
SC2-B
0850
1.0 UJ
3.4
0.13
0.050 U
0.29
0.033
0.030
19
SC3-A
1050
5.57
1.5
3.3
0.050 U
0.050 U
0.30
0.024
0.021
4
SC3-B
1100
1.0 U
3.1
0.053
0.095
0.18
0.023
0.020 U
20
DR
1140
6.11
1.7
3.9
0.45 J
0.050 U
0.38
0.037
0.023
9
MB1 -A
0920
8.32
2.9
3.9
0.075 J
0.050 U
0.38
0.032
0.020
4
MB1-A (d)
0920
7.48
2.2
3.8
0.050 U
0.050 U
0.41
0.031
0.029 J
4
MB1 -B
0930
1.9
3.6
0.075
0.050 U
0.56
0.054
0.048
9
MB2
1010
8.05
2.5
3.3
0.050 U
0.050 U
0.45
0.038
0.027
5
SC4-A
1145
6.21
2.0
2.9
0.050 U
0.050 U
0.30
0.021
0.020 U
5
SC4-B
1150
1.0 U
2.9
0.050 U
0.050 U
0.19
0.020 U
0.020 U
30
SC5-A
1010
4.69
1.0
2.9
0.050 U
0.050 U
0.23
0.020 U
0.020 U
5
SC5-B
1015
1.0 U
1.0 UJ*
0.050 U
0.050 U
0.17
0.020 U
0.020 U
25
MB3 -A
1105
4.95
1.1
3.2
0.050 U
0.050 U
0.27
0.020 U
0.020 U
3
MB3-B
1110
1.5
3.0
0.050 U
0.050 U
0.29
0.020
0.020
8
MB4
0750
7.95
1.8
3.2
0.050 U
0.050 U
0.52
0.093
0.033
4
MB4 (d)
0750
8.17
1.8
3.1
0.050 U
0.050 U
0.47
0.092
0.054
4
MSO
1035
5.49
1.2
3.3
0.050 U
0.050 U
0.36
0.088
0.060
3
GULF
0920
2.48
1.0
3.2
0.091 J
0.050 U
0.28
0.020 U
0.020 U
20
Pres. Blank
1.0 U
0.050 U
0.050 U
0.10 U
0.020 U
4.0 U
A - Average Value; J - Estimated Value; U - Material analyzed for but not detected (number is minimum quantitation limit); (d) - QA duplicate sample;
* - holding time exceeded due to instrument malfunction
-15-
-------
less than detection (0.05 mg/1) in 2000 except near point sources where concentrations were still
less than 0.2 mg/1. Again in 2001, ammonia and nitrate/nitrite concentrations were generally less
than detection except in the tributaries (CC, TMC, and DR) and in the upper ship channel (SCI,
SC2, and SC3). Higher 2001 ammonia concentrations in tributaries and the upper ship channel
may be due to greater freshwater discharge into the Bay during May than July resulting in more
nitrogen loading from upstream swamps. TKN concentrations were somewhat higher during the
ebb tide sampling in 2000 than during the high slack tide possibly due to TKN input to the bay
from Chickasaw Creek and Three Mile Creek. It should be noted that some of the reported 2000
TKN concentrations are flagged as estimated due to recovery problems encountered during
analysis. With a few exceptions, TKN concentrations in 2001 were higher in the upper layer of
the water column than in the lower layer at the same station. Total phosphorus concentrations in
2000 and 2001 generally varied throughout the bay from less than detection (0.020 mg/1) to less
than 0.1 mg/1. In 2000, only stations TMC and CC exceeded 0.1 mg/1 total phosphorus during the
slack tide sampling while total phosphorus exceeded 0.1 mg/1 only at MB1 and above and below
International Paper during ebb tide sampling. In 2001, 0.1 mg/1 total phosphorus was exceeded
only at station TMC during the low slack tide sampling. Finally, TSS samples were collected in
2001 at the headwater station (MR1), Chickasaw Creek (CC), and Three Mile Creek (TMC)
during both slack tide events. With the exception of the lower layer sample in Chickasaw Creek
(22 mg/1), the remaining TSS concentrations were in a fairly narrow range from 5-12 mg/1.
-16-
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Continuous DO Monitoring
In both 2000 and 2001, continuous recording DO meters were deployed at ten locations in
the bay and tributaries. Each meter was deployed from a floating buoy to maintain a probe depth
of approximately five feet (5') and recorded dissolved oxygen, salinity, pH, and temperature in 30
minute intervals throughout the deployment period. In addition, turbidity measurements were
recorded during the 2001 deployments at stations MR1, CC, DR, MB1, MB3, and MB4. Table 7
summarizes the continuous DO monitoring data for the two surveys.
Table 7 - Continuous DO Monitoring Summary
Station
July 2000
Min.-Max Ave
Number
of Hours
Deployed
May 2001
Min.-Max. Ave
Number
of Hours
Deployed
MR1
7.50 - 10.29 8.43
67.1
8.33 - 12.10 9.29
53.2
CC
3.91 -23.52 12.51
74.0
5.75 -7.38 6.43
69.9
TMC
2.47- 13.02 6.97
74.2
5.59 -9.24 7.06
69.5
DR
0.73 -9.13 5.22
69.8
3.45 -7.88 6.07
69.8
SCI
No Data - Meter Lost
-
4.98 -7.33 5.99
64.7
MB1
5.46-7.89 6.13
72.1
No Data - Probe
Malfunction
72.3
MB2
5.38 -7.10 6.06
70.3
5.68 -7.73 6.71
66.8
MB3
No Data - Meter Lost
-
2.55 - 8.14 5.96
71.8
MB4
5.15 -6.74 5.79
69.2
6.15 - 8.52 6.98
66.1
GULF
No Data - Meter Lost
-
No Data - Meter Lost
-
Upper West
Bay (UWB)
1.70-7.14 4.62
72.9
4.47 - 8.07 6.28
62.4
As shown in Table 7, there is tremendous daily variability in DO in the bay tributaries
-17-
-------
(Dog River, Three Mile Creek, and Chickasaw Creek). During portions of the day in 2000,
individual DO measurements at these stations fell well below 5 mg/1, while the overall average
DO levels at these stations during both surveys was above 5 mg/1; however, this average is
significantly affected by the supersaturated conditions also experienced during portions of the
deployment. Only the Upper West Bay station during the 2000 survey exhibited an average DO
for the monitoring period less than 5 mg/1 (4.62 mg/1). With the exception of MB3, the ship
channel (SCI) and Mobile Bay stations (MB1, MB2, and MB4) exhibited a relatively narrow
range of DO over the monitoring period from about 5 mg/1 to 8.5 mg/1. Observed DO was as
low as 2.55 mg/1 at MB3.
During the 2001 deployment, turbidity concentrations at MR1 ranged from 10 to 32 NTU
with an average of 20 NTU. Turbidity at CC and DR was in a slightly more narrow range of 11 -
20 NTU (16 NTU average) and 5-13 NTU (8 NTU average), respectively. Turbidity in the
middle bay was around the same level as in the tributaries. Specifically, at MB1 turbidity ranged
from 5-25 NTU with an average of 11 mg/1 while MB3 ranged from 4-17 NTU with a 7 NTU
average. Turbidity in the lower bay (MB4) was significantly higher ranging from 6-64 NTU
with an average of 31 NTU. Turbidity data for stations MB3 and MB4 were also plotted against
water level (tidal stage) at Fowl River and wind speed to determine if turbidity levels in the bay
are related to either tides or wind. As shown in Figures 5 and 6, higher turbidity levels occur
during lower tide stage. While it was expected that higher wind speed would correlate with
higher turbidity levels due to potential resuspension of bottom sediments, the effects of tide stage
on turbidity masks any influence by wind.
-18-
-------
Turbidity vs. Tide/Wind
Station MB3- May 2001
— Wind (fps)
~ Turbidity
(NTU)
* Relative
Tidal
Stage [ft)
Figure 5 - MBS Turbidity vs. Tide/Wind
Turbidity vs. Tide/Wind
Station MB4- May 2001
— Wind
(fps)
•* Tuibidity
(NTU)
* Relative
Tidal
Stage
(ft)
Figure 6 - MB4 Turbidity vs. Tide/Wind
Overall, calibration of continuous recording instruments was successful for both surveys;
however, difficulties for specific parameters on a few instruments were encountered. Following
the 2001 survey deployment, the instrument at MR1 read 7.90 mg/1 for a 7.45 mg/1 Winkler
-19-
-------
titration standard. The difference, 0.45 mg/1, exceeds the EAB tolerance for dissolved oxygen
calibration of 0.2 mg/1. Comparisons between DO reading from this meter and DST profiling DO
data at MR1 at approximately the same time and depth show the continuous meter also reading
approximately 0.25 mg/1 - 0.45 mg/1 higher than the profiling meter. Similarly, the instrument at
Three Mile Creek read the same Winkler standard (7.45 mg/1) at 7.15 mg/1 resulting in a
difference of 0.3 mg/1 versus EAB tolerance of 0.2 mg/1. Comparisons with DST profile data
confirm this slight underreading by the continuous meter. Also following the 2001 deployment,
the turbidity probes at stations DR and MB 1 read a 100 NTU turibidity standard as 69.6 NTU
and 84.9 NTU, respectively. Though of less importance to model development, it should be noted
that the pH probes at stations MB2 and MB4 following the 2001 deployment read a 7 pH
standard as 8.04 and 7.68 SU, respectively.
Following the 2000 deployment, several meters failed to measure the Winkler DO titration
standard within the EAB tolerance possibly due to growth on the instrument DO membrane.
Specifically, the instrument at MR1 was off by +1.48 mg/1. There is fairly close agreement
between the final continuous DO reading at MR1 and a profiling measurement taken a short time
later (difference of 0.22 mg/1); however, for model development and calibration, the modeling
team is recommended to rely on the DST profiling data for dissolved oxygen information for the
2000 survey at station MR1. Similarly, the meters at stations CC, TMC, DR, and MB1 deviated
from the Winkler standard by +0.60 mg/1, +0.39 mg/1, +0.45 mg/1, and -0.58 mg/1, respectively.
While the continuous DO data for these stations may be useful for evaluating the variation in DO
throughout a diurnal period, the DST profiling data is the recommended source of field data for
model setup and calibration.
-20-
-------
Due to tidal effects and stratification, the Diel Curve Method was not applied to the
Mobile Bay continuous DO data.
Production/Respiration
In order to determine production and respiration rates, light and dark bottle deployments
were conducted in both 2000 and 2001 at six stations including two bay stations (MB2 and MB3),
two ship channel stations (SC2 and SC5) and two tributary stations (CC and TMC). Tables 8 and
9 show the result gross primary production and respiration measurement results for 2000 and
2001, respectively.
Table 8 - July 2000 Production/Respiration
Station
Date
Incubation
Period
Gross Primary
Production (GPP)
(g 02/m2/day)
Respiration
(R)
(g 02/m2/mday)
GPP:R
Ratio
SC2
7/13/00
0900-1300
2.77
1.77
1.56
SC5
7/12/00
1415-1715
5.14
5.64
0.91
MB 2
7/13/00
1140-1520
1.12
1.04
1.08
MB 3
7/14/00
0915-1315
2.05
1.28
1.60
CC
7/15/00
1100-1500
0.62
0.73
0.85
TMC
7/15/00
1240-1600
3.96
2.50
1.59
During the 2000 and 2001 light/dark bottle experiments, samples were collected at
multiple depths (3-4 depths in the euphotic zone based on marine photometer light profiles) for
chlorophyll analysis for the purpose of providing instream chlorophyll data for model calibration
In 2001, chlorophyll samples were also collected at MB4. Tables 10 and 11 show the results of
chlorophyll a sampling for the 2000 and 2001 surveys, respectively.
-21-
-------
Table 9 - May 2001 Production/Respiration
Station
Date
Incubation
Period
Gross Primary
Production (GPP)
(g 02/m2/day)
Respiration
(R)
(g 02/m2/mday)
GPP:R
Ratio
MB 2
5/16/01
0840 - 1250
4.23
7.42
0.57
SC2
5/16/01
1000 - 1400
6.80
5.93
1.15
MB 3
5/17/01
0920 - 1330
3.73
3.97
0.94
SC5
5/17/01
1105 - 1510
5.64
5.94
0.95
MB 4
5/17/01
1225 - 1640
4.74
4.80
0.99
TMC
5/18/01
0900 - 1330
5.04
1.55
3.25
cc
5/18/01
1035 - 1435
5.54
2.40
2.31
In general, chlorophyll concentrations were much higher in 2000 than in 2001, presumably
because the 2000 study, conducted in July, took place in the middle of the growing season
whereas the growing season was just beginning in 2001. While concentrations for all stations
except Three Mile Creek were generally below 12 ug/1 in 2001, only station MB2 exhibited
concentrations below 12 u/gl at depths less than five feet in 2000. For both survey periods, Three
Mile Creek exhibited some of the highest chlorophyll concentrations ranging from 12.1 to 14.6
ug/1 in 2000 and from 13-40 ug/1 in 2001. Concentrations at station SC-2, well downstream of
Three Mile Creek, were as high in 2000 as in Three Mile Creek with a range of 37 - 43 ug/1 above
five feet. Concentrations in the high teens and twenties were observed as far down in the bay as
MB3.
Algal Growth Potential Tests (AGPT) were also run on samples collected at the P/R
stations in the Mobile Bay study area in order to determine the potential for algal enrichment of
the system. AGPT results for each survey are included in Tables 10 and 11. In general, a dry
-22-
-------
Table 10 - July 2000 Chlorophyll/AGPT
Date
Station
(AGPT, Dry Weight mg/1))
(Limiting Nutrient)
Depth (ft)
Chi a (ug/1)
7/12/00
SC5
0.5
12
(2.4)
0.5 (Duplicate)
12
(Nitrogen)
2.0
12
5.0
13
11.0
13
7/13/00
SC2
0.5
37
(3.9)
1.0
43
(Nitrogen)
2.5
39
5.5
8
7/13/00
MB2
0.5
7.5
(2.4)
1.5
8.2
(Nitrogen)
3.0
8.4
7.0
8.3
7.0 (Duplicate)
8.2
7/14/00
MB3
0.5
24
(6.0)
1.5
26
(Nitrogen)
3.0
18
3.0 (Duplicate)
16
7.5
19
7/15/00
TMC
0.5
29
(10.3)
1.5
37
(Nitrogen)
3.0
40
7.0
13
7/15/00
CC
0.5
14
(2.5)
1.5
15
(Nitrogen)
3.5
23
9.0
5.6
9.0 (Duplicate)
5.3
-23-
-------
Table 11 - May 2001 Chlorophyll/AGPT
Date
Station
(AGPT, mg/1)
(Lim. Nut.)
Depth (ft)
Chi a (ug/1)
Date
Station
(AGPT, mg/1)
(Lim. Nutrient)
Depth (ft)
Chi a (ug/1)
5/16/01
MB2
0.5
8.7
5/17/01
SC5 -Continued-
3
3.7
(2.4)
1
5.8
(1.5)
6.5
6.1
(Nitrogen)
3
8.0
(Nitrogen)
13
8.7
8
11.9
5/17/01
MB4
0.5
5.4
5/16/01
SC2
0.5
7.1
(1.4)
1.5
6.8
(i.i)
0.5 (Duplicate)
7.1
(Nitrogen)
1.5
(Duplicate)
7.0
(Nitrogen)
1.5
5.9
2.5
8.3
4
7.8
6
9.0
8
4.8
5/18/01
TMC
0.5
12.1
8 (Duplicate)
5.0
(25.0)
1
13.1
5/17/01
MB3
0.5
4.4
(Nitrogen)
2
14.6
(1.5)
1.5
4.2
4
12.4
(Not
determined)
1.5 (Duplicate)
4.2
4
(Duplicate)
13.4
2.5
4.6
5/18/01
CC
1
12.8
5.5
10.1
(8.2)
0.5
9.1
5.5 (Duplicate)
9.4
(Nitrogen)
1
9.3
10.5
11.6
3
8.4
10.5
(Duplicate)
11.1
6.5
7.6
5/17/01
SC5
0.5
2.8
6.5
(Duplicate)
7.7
weight AGPT greater than 10 mg/1 is considered an indication of enrichment in marine waters.
For both the 2000 and 2001 surveys, AGPT exceeded 10 mg/1 only at the Three Mile Creek
station (TMC) with the remaining stations all below 10 mg/1 indicating little enrichment in the
Mobile Ship Channel or Bay. For all stations, nitrogen was determined to be the limiting
nutrient.
-24-
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Diffusion/Reaeration
As part of the July 2000 survey, diffusion measurements were made at two locations in
order to determine an equivalent reaeration rate. Diffusion measurements for the Mobile surveys
utilized SESD/EAB's floating dome technique. The first measurement was made on July 14,
2000 in Dog River about two miles upstream of its mouth with a resulting reaeration rate of 0.15
1/day. The second measurement took place on July 16, 2000 in Chickasaw Creek about 1.25
miles upstream from its mouth. Using a depth of 7 meters based on observed stratification, the
resulting reaeration rate is 3.5 1/day; however, if a calculation is made using the entire water
depth at the measurement location of 10 meters, the resulting rate is 2.5 1/day.
In addition to dome method diffusion measurements, two gas/tracer reaeration studies
were conducted in Mobile Bay on July 13 south of SC-2 and on July 15, 2000 at MB1 (See
Figure 7). Utilizing krypton gas and Rhodamine WT dye, water samples were collected for
krypton analysis from the observed peak of the dye cloud over a period in excess of 4 hours. The
resulting gas reaeration rates were 1.82 1/day at 20° C on July 13 and 5.74 1/day at 20° C on July
15. Figures 8 and 9 show the prevailing currents and winds during the July 2000 gas/tracer
reaeration measurements.
During the May 2001 survey, a gas/tracer reaeration measurement was again made in
Mobile Bay southwest of SC-2 (See Figure 7). The resulting reaeration rate was found to be 2.37
1/day at 20° C. Prevailing wind/current vectors during this effort are shown in Figure 10. Also,
concurrent with the gas reaeration measurement, a floating dome diffusion measurement was
made in the same portion of the bay. The resulting rate of 3.86 1/day (at ambient temperature)
was in good agreement with the calculated reaeration rate at ambient temperature (3.20 1/day at
32.7° C).
-25-
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magna
tUcj-
May 16,2001 - Dye/Gas injection
July 13,2000 - Dye/Gas Injection
Figure 7 - Gas/Tracer Study Locations
-26-
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Wl
MO
NDV
BILE
**
ECTC
AIR!
re.:
7RSC
>OR7
4E1
KNO
Ml
is;
io
NT
_ ba
7/13/2O0O *
*
-
I
\
X
\
\
V
1
CUR,
MB-l
S l
Q W \
TORS (CA
VSEC
5
0800 0900 1000 1100 1200 1300 1400 1500 1600 1700
TIME
Figure 8 - 7/13/00 Reaeration Wind/Current Vectors
fe a
w v
BILE.
**RR
ECTORS
AIRPOR1
4ERA1
WOTS)
7a
£
>
• 7115/2 o h o *
y\\y
*
!
-
f
I
i
1
1
/
/
/
CUR
MB-l
IENT VECTORS (Ch
USEC
)
0800 0900 1000 1100 1200 1300 1400 1500 1600 1700
TIME
Figure 9 - 7/15/00 Reaeration Wind/Current Vectors
-27-
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Figure 10 - 5/16/01 Reaeration Wind/Current Vectors
Hvdrological/Meteorological Data
At the planning stage for this project, the Water Management Division indicated that
sufficient data existed for the development of a hydrodynamic model of the bay and only limited
hydrodynamic data would be needed to link the water quality datasets to a hydrodynamic model.
In addition, NOAA provides tide stage and current data for several locations in Mobile Bay which
could provide supplemental information for hydrodynamic modeling. As a result, only limited
hydrological data was collected during the 2000 and 2001 surveys. Hydrological data collected
during these surveys includes current direction/velocity and stage (water level). Meteorological
data includes wind speed/direction, and solar radiation collected in association with
production/respiration measurements.
In 2000, bay current speed and direction was measured at 10 minute intervals over a 3 day
-28-
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period at stations MB3 and MB4 and over a 5 day period at station MB1. At each station, the
current meter was deployed at middepth in the water column. In 2001, current meters were again
deployed at these stations at middepth over a 3 day period with a 10 minute measurement
interval. Also in 2001, a meter was located at middepth at station MS0. Figures 11-17 provide
oyster plots of current speed and direction as well as time series plots including temperature and
salinity for each station.
For both the 2000 and 2001 surveys, water level recorders were deployed at the Dog River
and Fowl River Marinas for the duration of the studies. Graphs of the water level data are
provided in Figures 18-21. Water level elevations atthe Fowl River Marina are referenced to
National Geodetic Vertical Datum (NGVD) through a NOAA tidal benchmark located at the
marina. No benchmark was available at the Dog River location, therefore these elevations are
reported relative to the mean water level for the record period.
In 2000 and 2001, wind speed and direction was measured at ten minute intervals at the
USS Alabama park located in the north portion of the Bay. Wind data are shown graphically in
Figures 22 and 23.
Problems were encountered with the EPA rain gage during the 2000 survey; however,
data obtained from the Mobile airport indicates 0.59" of rain fell on the afternoon of July 11
followed by 0.82" on the afternoon of July 16, 2000. No rainfall occurred at the SESD rain gage
during the 2001 survey.
Finally, solar radiation was measured on each day of production/respiration measurement
by recording pyroheliometer. A planimeter was then used to determine the amount of incident
solar radiation recorded on chart paper for each day of deployment. Table 12 provides the daily
solar radiation inLangleys for each production/respiration measurement.
-29-
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STATION MB-1 30
36.04N 87 57.91W
Speed Class Interval = 4.00
\
\
/
/
315
\
45
/
-
-
270 — <2^1
90
A
-
M
-
/
\ ®
225
135 3
/
u J X
8
/
2
180
Si
aj
OYSTEH PLOT OF SPEED AND DIRECTION
T
o
From 11-JUL-
0 To 16-JUL- 0
No. of Obs.
ENDECO Type 174SSM Solid
State Memory Current
Meter
Figure 11a - July 2000 - MBl Oyster Plot
Figure lib - July 2000 - MBl Time Series Plots
-30-
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STATION MB-3 30 22.015N B8 03.942W
Speed Class Interval = 4.00
0
180
OYSTER PLOT OF SPEED AND DIRECTION
From 11-JUL- 0 To 14-JUL- 0
ENOECO Type 174SSM Solid State Memory Current Meter
Figure 12a - July 2000 - MBS Oyster Plot
Figure 12b - July 2000 - MBS Time Series Plot
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STATION MB-4 30 19.00BN 87 52.961W
Speed Class Interval =4.00
OYSTER PLOT OF SPEED AND DIRECTION
From 11-JUL- 0 To 14-JUL- 0
ENDECO Type 174SSM Solid State Memory Current Meter
Figure 13a - July 2000 - MB4 Oyster Plot
Sin
STATION
MB — A
30 19.006N 8 ~7 52.961W
IS
13 194
195
196 197 196
IS
-S tu s
~ s| S-
13 19-4
T-J
|-1
195
V~~|
196 197 196
IS
& S
13 194 195 196 197 196
vVv^tA/Vv/x./
u
33 194
JULIAN DAYS
Endeco
195 196 197 196
11—JUL— O to 14—JUL— O
Type 174SSM Current Meter
Figure 13b - July 2000 - MB4 Time Series Plot
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STATION MB-1 N30 35.989 W087 SB.000
Spaed Class Interval - 16.00
0
/
OYSTER PLOT OF SPEED AND DIRECTION
From 15-MAY- 1 To 18-MAY- 1
ENDECO Type 174SSM Solid State Memory Current Meter
Figure 14a - May 2001 - MB1 Oyster Plot
o STATION MB—1 N30 35.9B9 W087 5Q.OOO
135 136
Sr
m
137 1
r r
36 133 140 :
135 136 131
"1
1
Ml
38 139 140
Itth
135 136 137 136 139 1-40
=H ™—¦—2— 1-" ¦ * f " 1 1—
135 136 137 138 139 1-40
JULIAN PAYS 15—MAY— 1 to 18-MAY- 1
Endeco Type 174SSM Current Meter
Figure 14b - May 2001 - MB1 Time Series Plot
-33-
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Figure 15a - May 2001 - MB3 Oyster Plot
Figure 15b - May 2001 - MBS Time Series Plot
-34-
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MB 4 N30 19.046 W08B 59.972
Speed Claaa Interval "2.00
0
OYSTER PLOT OF SPEED AND DIRECTION
From 15-MAY- 1 To IB-MAY- 1
ENDECO Type 174SSM Solid State Memory Current Meter
Figure 16a - May 2001 - MB4 Oyster Plot
1 E
MB A N30 ±9.046 WOSS 59.972
i:
1" ~ «=,
35 136 137 138 139 140
12
§ g s
15 136 137 138 139 140
^nrriifH
s is
15 136 137 138 139 140
A M /*\
135 136 137 138 139 140
JULIAN DAYS ±5—MAY— 1 to IB—MAY— 1
Endec o Type 174SSM Current Meter
Figure 16b - May 2001 - MB4 Time Series Plot
-35-
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Figure 17a - May 2001 - MSO Oyster Plot
1 i £
STATION MSO N30 17.648 W08S 07.2
12
S&1
n« ^
ft 0
15 136 137 13B 139 1-40
12
1 I a
15 136 137 138 139 140
jTjyni'ii iiri
i:
» I
15 136 137 138 139 140
135 136 137 138 139 1-40
JULIAN DAYS 15—MAY— 1 to IB—MAY- 1
Endeco Type 174SSM Current Meter
Figure 17b - May 2001 - MSO Time Series Plot
-36-
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Water Level Record - Dog River
JULY 11-16, 2000
DATE -TINE
Figure 18 - July 2000 Water Level - Dog River
Water Level Record - Fowl River I
July 11 -16, 2000
DATE -TINE
Figure 19 - July 2000 Water Level - Fowl River
-37-
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Water Level - Dog River
May 15-18,2001
Time
Figure 20 - May 2001 Water Level - Dog River
Water Level - Fowl River
May 15-18, 2001
Time
Figure 21 - May 2001 Water Level - Fowl River
-38-
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Wind Data - Mobile Bay Survey - July 2000
Figure 22 - July 2000 Wind
Wind Data - Mobile Bay Survey - May 2001
— Speed — Direction
Figure 23 - May 2001 Wind
-39-
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Table 12 - Solar Radiation
Date
Radiation
(Langleys)
7/12/00
489
7/13/00
526
7/14/00
399
7/1500
609
5/16/01
567
5/17/01
579
5/18/01
366
Sediment Oxygen Demand
During the July 2000 survey, sediment oxygen demand (SOD) measurements were made
at five locations in the Mobile Bay study area. In 2001, SOD rates were measured at seven
locations. SOD measurements were made using four replicate chambers at each station and an
average SOD was determined for each station. Table 13 provides the resulting SOD rate for each
station. These rates are corrected for water column respiration, which is also measured using two
replicate chambers, and are reported at ambient temperature.
As shown in Table 13, SOD rates were measured at the four Mobile Bay water quality
sampling stations and in the bay near the entrance to Dog River in 2000. SOD rates for the bay
water quality stations were in a fairly narrow range from approximately 1.5 to 3.0 g02/m2/day
with rates slightly higher in the lower bay (MB3 and MB4) than in the upper bay (MB1 and
MB2). The station near Dog River also fell in this range with a rate of 1.7 g02/m2/day. In
addition to these stations, stations were added in Mobile Bay near the entrance to Fowl River and
-40-
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Table 13 - SOD Rates
Station
Date
SOD
(g02/m2/day)
Temperature
(°C)
Diver
Observations
Mobile Bay near
Dog River entrance
7/11/2000
1.70
31.5
11' Deep
Fine Sandy Muck
MB1
7/12/2000
1.84
30.8
13' Deep
Fine Sandy Muck
MB2
7/12/2000
1.53
30.6
13' Deep
Fine Sandy Muck
MB 3
7/13/2000
3.00
30.4
15' Deep
Mucky Fine Sediment
MB 4
7/13/2000
2.66
31.1
13' Deep
Mucky Fine Sediment
Mobile Bay near
Dog River entrance
5/18/2001
1.27
27.3
12' Deep
Silty Clay w/ Shell
Fragments
Mobile Bay near
Fowl River entrance
5/17/2001
1.31
25.6
14' Deep
Brown Silt
Mobile Bay near
Mobile River mouth
5/16/2001
3.15
27.7
8' Deep
Sandy Silt
MB1
5/18/2001
1.47
26.2
13' Deep
Brown Silty Clay
MB2
5/17/2001
1.97
25.7
13' Deep
Brown Silt
MB 3
5/16/2001
1.35
25.6
14' Deep
Grey Mucky Fine
Sediment
MB 4
5/15/2001
1.83
25.2
12' Deep
Brown Flock over
Grey Mucky F ine
Sediment
below the mouth of the Mobile River for the 2001 survey. A planned measurement in the Mobile
River above Chickasaw Creek could not be completed due to conditions at the time. Overall,
SOD rates were lower in 2001 than in 2000. As in 2000, the bay water quality stations as well as
the station near Fowl River fell in a narrow, though slightly lower, range from 1.3 to 2.0
-41-
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g02/m2/day. The bay station near Dog River was near this range at just below 1.3 g02/m2/day.
The station below the Mobile River, however, was somewhat higher than the other stations
measured in 2001.
Point Source Sampling
For purposes of the model calibration/verification surveys, the Water Management Division
identified three point sources of interest. Specifically, WMD requested sampling data for
International Paper, Kimberly Clark, and Mobile/Clifton Williams WWTP. International Paper
discharges to the Mobile River approximately 1.25 miles upstream of Chickasaw Creek while
Kimberly Clark discharges to the Mobile River roughly 3/4 mile upstream of Chickasaw Creek.
The Mobile WWTP outfall is located at the north end of Mcduffie Island and discharges to the
Mobile River very near its mouth. Figure 24 shows these locations within the study area.
In addition to the facilities of interest to the Water Management Division, sampling was
conducted at the Mobile/Three Mile Creek (W. Smith) WWTP and the Prichard WWTP to allow
these facilities to be easily integrated into the water quality model if they were later determined to
be of significance to wasteload allocation or total maximum daily load determinations. Sample
collection and insitu measurements were performed by survey participants from the Alabama
Department of Environmental Management's Mobile office. Tables 14 and 15 provide the results
of the effluent sampling and insitu measurements for the 2000 and 2001 surveys, respectively.
Effluent samples collected were 24 hour composite samples. Flows reported in Tables 14
and 15 represent the flow from each facility over the 24 hour compositing period. According to
ADEM, in December 2000 International Paper shut down its Mobile facility thus resulting in a
decrease in flow between the 2000 and 2001 studies from 27.5 MGD to 0.69 MGD. Also, in
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OakleighjEst
Beach Estate's,!*
International Paper|
.Chickasaw
Kimberly Clark |
(Blakeley
Orchard
^Overlook Enates
Toulminville
Crichton
Country Club Estates
Mobile/Williams WWTP
Ft'MsQejTnott.
ackson Heights | I
•*Eau Claire Estates!
Oakuiood Estates
Famell
Moiult
| Skyland.Park^ Estates
Village. Point/
Daphne
1 Dog River Point
f[7AB
flagged1
Rabbit Creek Estates^
JtlSAB
Theodore
'-DELORME
Figure 24 - Point Source Locations
-43-
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Table 14 - July 2000 Point Source Sampling Results
International
Paper
Kimb erly
Clark
Mobile/
Williams
WWTP
Mobile/
Smith WWTP
Prichard
WWTP
NPDES#
AL0002780
AL0002801
AL0023086
AL0023094
AL0023205
Date
7/12/00
7/12/00
7/12/00
7/12/00
7/12/00
Time
1140
1325
1235
1130
1145
Flow (MGD)
27.5
34.4
20.6
10.2
1.0
DO (mg/1)
0.2
8.84
7.22
6.0
7.8
Temp. (°C)
36.1
33
30.5
29.6
28.7
pH (SU)
7.7
8.4
6.6
6.7
7.4
Conductivity (uMho)
1960
735
12180
50700
52200
Total BODU (mg/1)
192.3
42.1
105.8
56.9
22.9
CBOD5 (mg/1)
25 J
4.7 J
2.0 UJ
6.8 J
2.0 UJ
NH3-N (mg/1)
0.566
3.20
15.6
2.82
1.36
N02/N03 (mg/1)
0.050 U
0.293
0.484
12.1
0.074
TKN (mg/1)
9.3
5.99
17.0
6.48
2.76 J
Tot. Phosphorus
(mg/1)
3.09
1.42
2.62
3.28
1.60
Diss. Phosphorus
(mg/1)
0.28
1.24
2.08
2.80
1.45
A - Average Value; J - Estimated Value; U - material analyzed forbut not detected; BODU is corrected for dilution.
Table 15 two values are shown for ultimate BOD and CBOD5 results. The first number of each
pair represents the analytical result corrected for dilution for a sample comprised of 10% effluent
sample and 90% laboratory dilution water. The second value in the pair is the analytical result
corrected for dilution for a 25% effluent sample. The time reported in each table is the end time
for sample compositing and the time at which insitu measurements were made.
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Table 15 - May 2001 Point Source Sampling Results
International
Paper
Kimb erly
Clark
Mobile/
Williams
WWTP
Mobile/
Smith WWTP
Prichard
WWTP
NPDES #
AL0002780
AL0002801
AL0023086
AL0023094
AL0023205
Date
5/16/01
5/16/01
5/16/01
5/16/01
5/16/01
Time
0840
0750
0740
0900
0800
Flow (MGD)
0.69
34.1
20.2
9.38
1.41
DO (m g/1)
6.9
10.6
7.5
7.7
8.2
Temp. (°C)
26
28
25
25
23
pH (SU)
7.8
8.5
6.6
6.7
7.5
TOC (mg/1)
47
14
29
17 J*
12
Total BODU (mg/1)
(10%/25%)
22.1/26.0
42.3/39.8
135.1/1 34.5
24.4/36.1
20.4/19.0
CBOD5 (mg/1)
(10 %/2 5 %)
12/6.3
12/8.6
19/18
15/11
8.8/7.6
NH3-N (mg/1)
0.47
2.20
20
1.3
0.46
N02/N03 (mg/1)
0.50
4.8
0.050 U
16
0.052
TKN (mg/1)
4.9
5.2
23
3.4
2.1
Tot. Phosphorus
(mg/1)
1.3
0.92
3.0
2.3
0.96
Diss. Phosphorus
(mg/1)
1.3
0.90
2.9
2.3
0.80
A - Average Value; J - Estimated Value; U - material analyzed forbut not detected; * - Holding time exceeded due to instrument malfunction.
BODU results reported by th e laboratory are correcte d for dilution (% sampl e shown in paranthese).
According to EPA's Envirofacts Warehouse website, International Paper and Kimberly
Clark have National Pollutant Discharge Elimination System (NPDES) permit limits for only two
water quality parameters measured by EPA during the two intensive surveys. Both facilities must
maintain a pH between 5 and 9 standard units while International Paper has an effluent
temperature limit of 95 °F (35 °C) and Kimberly Clark has an effluent temperature limit of 100 °F
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(37.8 °C). International Paper slightly exceeded the temperature limit in 2000; otherwise, the
remaining measured temperatures and pH for these facilities were in compliance with NPDES
limits. Of the parameters measured during these surveys, the Envirofacts site indicates that the
Mobile/Williams WWTP is required to maintain a pH between 6 and 9 standard units and a BOD5
less than 30 mg/1. Both these limits were met during both surveys. Finally, the Envirofacts site
shows effluent limitations on the Mobile/Smith WWTP and Prichard WWTP for BOD5 (15 mg/1),
ammonia-nitrogen (5 mg/1), dissolved oxygen (5 mg/1), and pH (6 - 9 SU). These effluent
limitations were met during both intensive surveys at both facilities.
Conclusion
The Mobile Bay water quality surveys conducted in July 2000 and May 2001 successfully
obtained the necessary water quality data and information to enable the Water Management
Division to calibrate and verify a 3-dimensional, dynamic water quality model of the bay.
Significant profiling both longitudinally and laterally in the bay and tributaries coupled with
extensive continuous meter coverage provides a comprehensive picture of dissolved oxygen,
salinity, and temperature within the bay and tributaries. Comprehensive water quality sampling of
ambient water and point sources along with specialized studies of bay oxygen dynamics including
reaeration, production/respiration, and sediment oxygen demand provide a vast amount of data
and information in support of model calibration and verification. In addition, appropriate
hydrodynamic data collected to characterize tidal conditions (currents, tide heights) allows the
modeling team to tie this water quality data to an existing hydrodynamic model. The surveys also
met the objective of providing data over a range of conditions as demonstrated by the differences
in chlorophyll concentrations and ambient water temperatures between the surveys. Finally,
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supplemental information collected during the 2001 survey including DST profiling in Oyster Bay,
Weeks Bay, Magnolia River, and the Intracoastal Waterway and water quality sampling of two
additional point sources (collected both on both surveys) provides information to allow these
systems to be added to the modeling framework, if necessary, while total suspended solids
analyses of bay tributaries including Dog River, Three Mile Creek, and the Mobile River, and
turbidity measurement at several continuous measurement stations provide a better understanding
of solids concentrations within the study area.
It is recommended that the modeling team pay special attention to the discussions related
to calibration of the continuous and profiling meters since some of the these meters fell out of
calibration during deployment.
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