Water-Level Measurements in Dauphin Island, Alabama, 

From the 2013 Hurricane Season 

By Patrick J. Dickhudt, Christopher R. Sherwood, and Nancy T. Dewitt 

Open-File Report 2014–1245 

U.S. Department of the Interior 

U.S. Geological Survey
U.S. Department of the Interior 

SALLY JEWELL, Secretary 

U.S. Geological Survey 

Suzette M. Kimball, Acting Director 

U.S. Geological Survey, Reston, Virginia: 2015 

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Although this information product, for the most part, is in the public domain, it also may 

contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items 

must be secured from the copyright owner. 

Suggested citation: 

Dickhudt, P.J., Sherwood, C.R., and Dewitt, N.T., 2015, Water-level measurements in Dauphin Island, Alabama, 

from the 2013 hurricane season: U.S. Geological Survey Open-File Report 2014–1245, 24 p., 

http://dx.doi.org/10.3133/ofr20141245. 

ISSN 2331-1258 (online) 
iii 

Acknowledgments 

The authors thank Jeff Krause of Dauphin Island Sea Lab at the State of Alabama Marine Science Institution for his 

technical assistance at the lab and for sharing the lab and storage space. The mayor and property owners of 

Dauphin Island graciously allowed us to install our sensors on their property; this project could not have been 

completed without their generous assistance. The work detailed in this report was part of the Barrier Island 

Evolution Research Project of the U.S. Geological Survey (USGS). The authors thank the following USGS staff for 

their assistance: Joe Long and Soupy Dalyander for help with site selection and sensor installation; Kristy Guy for 

preparing the visually appealing site maps; and B.J. Reynolds for assistance recovering gear and surveying the 

sensor elevations. 

v 

Contents 

Acknowledgments ....................................................................................................................................................... iii

Abstract ...................................................................................................................................................................... 1

Introduction ................................................................................................................................................................. 1

Instrumentation ........................................................................................................................................................... 1

RBR DR1060 Pressure Logger ............................................................................................................................... 1

RBR Virtuoso D|wave ............................................................................................................................................. 2

Onset Hobo U20 Water-Level Logger ..................................................................................................................... 2

Well Installation ....................................................................................................................................................... 2

Site Description ........................................................................................................................................................... 3

Dauphin Island ........................................................................................................................................................ 3

Site 965 ................................................................................................................................................................... 4

Site 966 ................................................................................................................................................................... 4

Site 967 ................................................................................................................................................................... 4

Site 968 ................................................................................................................................................................... 4

Site 969 ................................................................................................................................................................... 4

Site 970 ................................................................................................................................................................... 4

Site 971 ................................................................................................................................................................... 4

Site 972 ................................................................................................................................................................... 4

Site 973 ................................................................................................................................................................... 5

Site 974 ................................................................................................................................................................... 5

Site 975 ................................................................................................................................................................... 5

Site 976 ................................................................................................................................................................... 5

Results ........................................................................................................................................................................ 5

References Cited ........................................................................................................................................................ 6

Figures ........................................................................................................................................................................ 7

Tables ....................................................................................................................................................................... 22

Figures 

1. Locations of sites on Dauphin Island, Alabama, used to monitor water levels, atmospheric pressure, and 

temperatures from July 22 through November 20, 2013 ................................................................................ 7

2. Photographs of RBR DR1060 pressure logger used on Dauphin Island, Alabama, in 2013 .......................... 8

3. Photograph of the RBR Virtuoso D|wave sensor used on Dauphin Island, Alabama, in 2013 ....................... 9

4. Photograph of one of the Onset Hobo U20 pressure loggers and threaded stainless-steel rod used on 

Dauphin Island, Alabama, in 2013 ............................................................................................................... 10

5. Photographs illustrating the procedure for the installation of a buried well on Dauphin Island, Alabama, in 

2013 ............................................................................................................................................................. 11

6. Photographs of well casings strapped to pilings of porches on Dauphin Island, Alabama, in 2013 ............. 12

7. Photographs of Global Position System (GPS) base station and rover on Dauphin Island, Alabama, in 

2013. ............................................................................................................................................................ 13

8. Photographs illustrating burial of well at site 968. ........................................................................................ 14

9. Atmospheric pressure time series from National Oceanic and Atmospheric Administration station DPIA1 

and USGS measurements from an Onset Hobo U20 pressure sensor at site 965 on Dauphin Island, 

Alabama, in 2013 ......................................................................................................................................... 15
vi 

10. Atmospheric pressure and temperature time series from an Onset Hobo U20 atmospheric pressure sensor 

mounted on a residential porch railing at site 965 on Dauphin Island, Alabama, in 2013 ............................ 16

11. Water-level time series from an RBR DR1060 pressure logger mounted in a buried well at site 966 on 

Dauphin Island, Alabama, in 2013 ............................................................................................................... 17

12. Water-level time series from an RBR Virtuoso D|wave pressure logger mounted in a buried well at site 968 

on Dauphin Island, Alabama, in 2013 .......................................................................................................... 17

13. Water-level time series from an Onset Hobo U20 pressure logger mounted in a buried well at site 969 on 

Dauphin Island, Alabama, in 2013 ............................................................................................................... 18

14. Water-level time series from an RBR DR1060 pressure logger mounted in a buried well at site 970 on 

Dauphin Island, Alabama, in 2013 ............................................................................................................... 18

15. Water-level time series from an RBR DR1060 pressure logger mounted in a buried well at site 971 on 

Dauphin Island, Alabama, in 2013 ............................................................................................................... 19

16. Water-level time series from an RBR DR1060 pressure logger mounted in a buried well at site 972 on 

Dauphin Island, Alabama, in 2013 ............................................................................................................... 19

17. Water-level time series from an Onset Hobo U20 pressure logger mounted in a buried well at site 973 on 

Dauphin Island, Alabama, in 2013 ............................................................................................................... 20

18. Water-level time series from an Onset Hobo U20 pressure logger mounted in a buried well at site 974 on 

Dauphin Island, Alabama, in 2013 ............................................................................................................... 20

19. Water-level time series from an Onset Hobo U20 pressure logger mounted in a buried well at site 975 on 

Dauphin Island, Alabama, in 2013 ............................................................................................................... 21

20. Water-level time series from an Onset Hobo U20 pressure logger mounted in a buried well at site 976 on 

Dauphin Island, Alabama, in 2013 ............................................................................................................... 21

Tables 

1. Mooring log sensor, location, and deployment information .......................................................................... 22

2. National Oceanic and Atmospheric Administration benchmarks on Dauphin Island, Alabama .................... 23

3. Instrumentation and data files for measuring water levels, atmospheric pressure, and temperature at 

Dauphin Island, Alabama ............................................................................................................................. 24
vii 

Conversion Factors 

SI to Inch/Pound 

Multiply By To obtain 

Pressure 

kilopascal (kPa) 0.0099 atmosphere, standard (atm) 

kilopascal (kPa) 0.01 bar 

kilopascal (kPa) 0.296 inch of mercury at 60oF (in Hg) 

kilopascal (kPa) 0.145 pound-force per square inch (lbf/in2

) 

kilopascal (kPa) 20.89 pound per square foot (lb/ft2

) 

Length 

centimeter (cm) 0.3937 inch (in.) 

millimeter (mm) 0.03937 inch (in.) 

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi) 

kilometer (km) 0.5400 mile, nautical (nmi) 

meter (m) 1.094 yard (yd) 

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows: 

°F=(1.8×°C)+32 

The SI unit for pressure is the pascal (Pa). 1 Pa = 0.0001 decibar (dbar) = 0.001 kilopascal (kPa). 

Vertical coordinate information is referenced to North American Vertical Datum of 1988 (NAVD88). 

Horizontal coordinate information is referenced to North American Datum of 1983 (NAD83). 

Elevation, as used in this report refers, to distance above the vertical datum.

1 

Measurements in Dauphin Island, Alabama, From the 2013 

Hurricane Season 

By Patrick J. Dickhudt, Christopher R. Sherwood, and Nancy T. Dewitt 

Abstract 

This report describes the instrumentation, field measurements, and processing methods used by 

the U.S. Geological Survey to measure atmospheric pressure, water levels, and waves on Dauphin 

Island, Alabama, in 2013 at part of the Barrier Island Evolution Research project. Simple, inexpensive 

pressure sensors mounted in shallow wells were buried in the beach and left throughout the hurricane 

season. Additionally, an atmospheric pressure sensor was mounted on the porch of a private residence to 

provide a local atmospheric pressure measurement for correcting the submerged pressure records. 

Introduction 

The U.S. Geological Survey (USGS) measured atmospheric pressure, water levels, and waves on 

Dauphin Island, Alabama, from July 22 through November 20, 2013, as part of the Barrier Island 

Evolution Research (BIER) Project, which aims to assess the effects of individual, short-term storms on 

the historical and geological evolution of the coastal system. Barrier islands are dynamic systems that 

can experience substantial morphological change (erosion and deposition) during storms. Water levels 

around barrier islands are influenced by winds, waves, and atmospheric pressure during the passage of 

storms, and the morphological effects of storms depend, in part, on the magnitude of inundation and 

water-level gradients across the island. Direct water-level measurements on barrier islands during 

storms are somewhat uncommon because equipment is often lost, buried, or destroyed during these 

high-energy events. 

This report describes the instrumentation, field methods, and data processing techniques used to 

measure water levels and waves with relatively inexpensive pressure sensors in a rapidly evolving 

barrier island system (fig. 1). These water-level and wave measurements can be used to validate 

numerical models and help interpret the morphological response of barrier islands to storms. 

Instrumentation 

RBR DR1060 Pressure Logger 

The RBR DR1060 (fig. 2) is a small submersible pressure logger capable of recording more than 

2 million samples at frequencies up to 1 hertz (Hz). These pressure loggers were temperature 

compensated and had pressure sensors with a depth rating of 10 meters (m). The manufacturer-specified 

accuracy was ±0.05 percent of full scale (about 0.005-m water depth) and resolution was 0.001 percent 

of full scale (about 0.0001-m water depth). Each RBR DR1060 was mounted on a rigid metal rod 

connected to the cap of a buried well jetted into the beach (described in “Well Installation”). The RBR 
2 

DR1060s recorded pressure every 5 seconds. At this sample rate, the RBR DR1060s could sample for 

about 5 months before running out of memory. 

RBR Virtuoso D|wave 

The RBR Virtuoso D|wave (fig. 3) is a small submersible pressure logger capable of sampling 

continuously or in burst mode at speeds up to 6 Hz and can store 30 million individual readings. This 

unit was temperature compensated and had a pressure sensor with a depth rating of 10 m. The 

manufacturer-specified accuracy was ±0.05 percent of full scale (about 0.005 m water depth) and 

resolution was 0.001 percent of full scale (about 0.0001 m water depth). The RBR Virtuoso D|wave was 

mounted on a rigid metal rod connected to the cap of a buried well jetted into the beach next to a piling 

of a residential porch (described in “Well Installation”). The well casing was secured to the porch piling 

with hose clamps and ratchet straps. The D|wave recorded pressure measurements continuously at 4 Hz 

from July 21, 2013, until its batteries died on October 24, 2013. 

Onset Hobo U20 Water-Level Logger 

The Onset Hobo U20 water-level logger (fig. 4) is a small submersible pressure logger capable 

of recording about 22,000 pressure and temperature samples at rates up to 1 Hz. Two models of Onset 

Hobo U20s were deployed: model U20–001–04 pressure sensors with ranges of 0 to 15 decibars (about 

0–4 m water depth) were used as atmospheric and submersible sensors; and model U20–001–01 

pressure sensors with ranges of 0 to 21 decibars (about 0–9 m water depth) were used as submerged 

sensors. The U20–001–04 sensor has a water-level accuracy of ±0.075 percent of full scale (about 0.003 

m water depth) and water-level resolution of 0.001 m water depth. The U20–001–01 used as a 

submerged sensor has a water-level accuracy of 0.05 percent of full scale (about 0.005-m water depth) 

and water-level resolution of 0.002 m water depth. 

The U20–001–04 sensor used as an atmospheric sensor was mounted in a small white PVC tube 

with vents, and attached with hose clamps to the railing of a residential porch. The sensor was mounted 

about 4 m above ground level. The submerged Onset Hobo U20s were mounted on rigid metal rods 

connected to the cap of buried wells jetted into the beach (described in “Well Installation”). Each Onset 

Hobo U20 collected a pressure measurement every 600 seconds for the duration of the deployment. At 

this sample rate, the Onset Hobo U20s could sample for about 5 months before running out of memory. 

Well Installation 

The Onset Hobo and RBR DR1060 pressure sensors buried in the beach were encased in 4.8-

centimeter (cm; outside diameter) schedule 80 polyvinyl chloride (PVC) slotted well screen. The RBR 

Virtuoso D|wave had a larger diameter and was encased in an 8.9-cm (outer diameter) schedule 80 PVC 

slotted well screen. The well casings were about 1.5 m long and were screened with 0.15-millimeter 

(mm)-wide slots along most of their length. A PVC well point with a 1.25 cm diameter hole drilled 

through its center (to allow a water jet to exit) was screwed on to the lower end of each well. Wells were 

installed by first digging a shallow hole (30 to 50 cm deep) and then using a 2.54-cm (1-inch) gasolinepowered water pump to jet the well into the sand until the top of the well was below the level of the 

beach (fig. 5). A pressure sensor was hung from a threaded rod attached to a PVC cap that screwed into 

the top of the well after jetting. The distance from the well cap to the pressure sensor is provided in table 

1 and approximates the pressure-sensor depth below the sediment surface. Wells on the Gulf of Mexico 

side (mooring numbers 968, 970, and 971) were in an energetic surf zone setting (fig. 6A) and were 
3 

jetted into the beach next to the pilings of waterfront residences and secured to the pilings with hose 

clamps and ratchet straps (fig. 6A and B). 

The elevation of the well cap was established using post-processed static Global Positioning 

System (GPS) data. A GPS base station was placed on the National Geodetic Survey (NGS) tidal 

benchmark PID BH1755 at the entrance into Fort Gains on the east end of Dauphin Island, and a GPS 

rover unit was used to survey the wells. The error between the base and the rover increased 

exponentially with distance from the base station (Waypoint Consulting Inc., 2005) as reflected by an 

increase in the root mean squared (RMS) error of the differentially corrected navigation data. All wells 

were within 12 kilometers of the base station. 

The GPS base station and the rover were duplicate systems with Ashtech Z-Xtreme GPS 

receivers, internal data recorders, Thales choke-ring antennae, and tripods (fig. 7A). After the wells 

were installed, the GPS rover was positioned and referenced to a dimple on the well cap (fig. 7B). Both 

receivers recorded the 12-channel full-carrier-phase positioning signals (L1/L2) from the satellites and 

recorded their positions concurrently at 1-second (s) intervals for at least 30 minutes (min). This 30-min 

GPS static occupation session was repeated when the wells were recovered months later. 

All GPS static sessions were processed using NovAtel GrafNet version 8.4 software, accounting 

for antenna height, antenna model, and GPS session type (rover or base). The NGS-published latitude, 

longitude, and ellipsoid height referenced to the North American Datum 1983 (NAD83) were 

transformed into World Geodetic System 1984 (WGS84; G1150) using the NGS Horizontal TimeDependent Positioning (HTDP) version 3.2.3 utility for postprocessing purposes (table 2). The 

processed position heights were referenced to the top of the well cap and converted to NAD83 

(CORS96) using the NGS HTDP utility. These processed heights were then processed through the NGS 

GEOID96 model to obtain geoid heights. The elevation of the pressure sensor was then determined by 

subtracting the distance from the well cap to the pressure sensor (table 1) from the cap elevation. 

The uncertainty of the elevation of the water-level sensor was estimated by using the square root 

of the sum of the squared individual error terms. The individual error terms included difference in 

surveyed well cap heights as measured upon deployment and recovery, the estimated error in the length 

of the threaded rods the sensors were suspended from, and the standard deviation of the GPS elevation 

measurements for a particular well. In addition, for wells on the Gulf of Mexico side of Dauphin Island 

that were strapped to porch pilings, the error in the measured distance from the well cap to a surveyed 

mark on the porch was included. The estimated uncertainty in the water-level sensor elevations ranged 

from 0.008 to 0.036 m (table 1). 

Site Description 

Dauphin Island 

Dauphin Island is a populated, low-lying barrier island in the northern Gulf of Mexico (fig. 1). It 

is bordered by Mobile Bay to the east, Mississippi Sound to the north and west, and the Gulf of Mexico 

to the south. Dauphin Island is frequently exposed to the force of hurricanes from the Gulf of Mexico, 

the most recent of which was Hurricane Katrina in 2005, which breached the western portion of the 

island. 
4 

Site 965 

Site 965 was at a residence off St. Stephens Street. An Onset Hobo U20–001–04 atmospheric 

pressure sensor was mounted in a PVC tube that was hose clamped to the second floor porch railing of 

the residence. 

Site 966 

Site 966 was in a small channel in an empty lot on the Mississippi Sound side of the island about 

200 m to the west of St. Stephens Street. An RBR DR1060 pressure sensor was mounted in a well 

buried in the beach. 

Site 967 

Site 967 was on the beach on the Mississippi Sound side of the island and to the north of the 

public parking lot at the western end of the island. An RBR DR1060 pressure sensor was mounted in a 

well buried in the beach. The sensor at site 967 could not be located for recovery, so the data were lost. 

Site 968 

Site 968 was on the Gulf of Mexico side of the island at a residence on Bienville Boulevard. An 

RBR Virtuoso D|wave was mounted in a well buried in the beach and strapped to a piling on the 

southeastern side of the residence. The piling the instrument was strapped to was in the swash zone of 

the beach at high tide when the instrument was deployed. About 0.6 to 0.8 m of sediment had 

accumulated at this site between deployment and recovery, completely burying the well (fig. 8) and 

making recovery difficult. 

Site 969 

Site 969 was on the Mississippi Sound side of the island in a small channel near Sam Houston 

Road. An Onset Hobo U20–001–01 pressure sensor was mounted in a well buried in the beach. 

Site 970 

Site 970 was on the Gulf of Mexico side of the island at a residence on Bienville Boulevard. An 

RBR DR1060 was mounted in a well buried in the beach and strapped to a piling on the southeastern 

side of the residence. 

Site 971 

Site 971 was on the Gulf of Mexico side of the island at a residence on Seneca Street. An RBR 

DR1060 was mounted in a well buried in the beach and strapped to a piling on the southwestern side of 

the residence. 

Site 972 

Site 972 was along the beach on the Mississippi Sound side of the island. An RBR DR1060 

pressure sensor was mounted in a well buried in the beach. 
5 

Site 973 

Site 973 was directly between sites 971 and 972 in the middle of the island. An Onset Hobo 

U20–001–04 pressure sensor was mounted in a well buried in the sand. 

Site 974 

Site 974 was in the middle of the island between sites 967 and 968 in a lot behind a home on 

Bienville Boulevard. An Onset Hobo U20–001–01 pressure sensor was mounted in a well buried in the 

sand. 

Site 975 

Site 975 was in the middle of the island in a channel in an empty lot just off St. Stephens Street 

and between sites 966 and 970. An Onset Hobo U20–001–04 pressure sensor was mounted in a well 

buried in the sand. 

Site 976 

Site 976 was along the beach on the Mississippi Sound side of the island very near the inlet of 

the canal next to St. Stephens Street. An Onset Hobo U20–001–01 pressure sensor was mounted in a 

well buried in the beach. Sometime before recovery, a large pile of sand (about 1 m high by 2 m in 

diameter) was placed over the sensor location and had to be removed so the instruments could be 

recovered. 

Results 

Atmospheric pressure data were collected continuously from July 22 to November 20, 2013, by 

the sensor mounted at site 965. The data appear to be of good quality but differ at times from data 

collected by the nearest land-based atmospheric pressure sensors. Specifically, the sensor at 965 shows 

larger variations in pressure than the sensors at National Oceanic and Atmospheric Administration 

(NOAA) gauge DPIA1, approximately 7 kilometers (km) east of site 965 (fig. 9). These pressure 

excursions may be real (for example, due to short-term pressure fluctuations caused by frontal passages) 

or they may be artifacts of sensor exposure to sun and wind. Figure 10 is a time-series plot of 

atmospheric pressure and temperature from site 965. 

Pressure sensors encased in wells buried in the beach were deployed from July 2013 through 

November 2013 (table 1). All data from the wells were of very high quality with no evidence of error 

due to fouling or attenuation from burial. One sensor (at site 967) could not be located and was never 

recovered, so there are no data for that site. Three sensors stopped sampling early due to battery failure. 

The RBR D|wave sensor at site 968 stopped operating on October 24, the RBR DR1060 sensor at site 

970 stopped operating on August 28, and the RBR DR1060 sensor at site 972 stopped operating on 

October 3. 

Water levels were derived from the well pressure sensors by subtracting atmospheric pressure 

linearly interpolated (in time) from measurements taken every 60 minutes at NOAA gauge DPIA1. The 

corrected pressure data were converted from decibars to water depth using an assumed seawater density 

of 1022.3 kilograms per cubic meter (calculated from salinity of 34 practical salinity units and 

temperature of 26 degrees Celsius, a typical salinity and approximately the mean temperature) and 
6 

adjusted to a common datum (North American Vertical Datum of 1988 [NAVD88]) using the surveyed 

cap elevation and the measured distance from the cap to the pressure sensor (table 1). Time series plots 

of water-level data from the buried wells are shown in figures 11 through 20. In the water-level plots, 

the reported water level is NAVD88 orthometric height referenced to the NGS GEOID96 datum. 

Data from all instruments were converted to standard format for USGS time series (Montgomery 

and others, 2009) and stored in network common data format (netCDF) files. NetCDF files store data 

and associated metadata in a format that is compact and machine-independent. Documentation of the 

USGS Oceanographic Time-Series Measurement Database can be found in Open-File Report 2007–

1194 (http://woodshole.er.usgs.gov/pubs/of2007-1194/). Details of instrumentation used for 

measurement of water levels, atmospheric pressure, and temperature are provided in table 3. 

References Cited 

Montgomery, E.T., Martini, M.A., Lightsom, F.L. and Butman, Bradford, 2009, Documentation of the 

U.S. Geological Survey oceanographic time series measurement database (February 2009 revision): 

U.S. Geological Survey Open-File Report 2007–1194, http://pubs.usgs.gov/of/2007/1194/. 

Waypoint Consulting Inc., 2005, Static baseline accuracies as a function of baseline length, observation 

time and the effect of using the precise ephemeris: Waypoint Consulting Incorporated, 12 p., accessed 

September 2, 2014 at 

http://www.novatel.com/assets/Documents/Waypoint/Reports/Static_Accuracies.pdf. 

 
7 

Figures 

Figure 1. Locations of sites on Dauphin Island, Alabama, used to monitor water levels, atmospheric pressure, 

and temperatures from July 22 through November 20, 2013. Red dots on map indicate locations of sites.Inset base 

from the National Atlas of the United States, 2009. Aerial photo base from the U.S. Department of Agriculture, 

National Agricultral Imagery Program, 2011. 

 
8 

Figure 2. Photographs of RBR DR1060 pressure logger used on Dauphin Island, Alabama, in 2013. A, Close-up 

of RBR DR1060 pressure logger. B, RBR DR1060 pressure logger connected to well cap by threaded stainlesssteel rod. The pressure senor is inserted into well casing and cap is screwed onto top of well (fig. 5E). 
9 

Figure 3. Photograph of the RBR Virtuoso D|wave sensor used on Dauphin Island, Alabama, in 2013. 
10 

Figure 4. Photograph of one of the Onset Hobo U20 pressure loggers and threaded stainless-steel rod used on 

Dauphin Island, Alabama, in 2013. 
11 

Figure 5. Photographs illustrating the procedure for the installation of a buried well on Dauphin Island, Alabama, 

in 2013. A–C, well casing being jetted into the sand; D, well casing at the end of jetting; E, pressure sensor inserted 

into the casing; and F, completed installation with pressure sensor inserted and cap screwed into the well casing. 
12 

Figure 6. Photographs of well casings strapped to pilings of porches on Dauphin Island, Alabama, in 2013. A, 

The well casing at site 968 after being buried and strapped to a piling on the porch of a private residence. B, The 

well casing at site 971 after being buried and strapped to a porch piling. 
13 

Figure 7. Photographs of Global Position System (GPS) base station and rover on Dauphin Island, Alabama, in 

2013. A, Base station near the entrance of Fort Gaines on the eastern side of Dauphin Island. B, U.S. Geological 

Survey Scientists surveying the well at site 972 with a GPS rover before recovering the sensor from the well. 

Erosion of the beach on the Mississippi Sound side of the island beach between deployment and recovery left the 

top of the well at site 972 exposed. 
14 

Figure 8. Photographs illustrating burial of well at site 968. A, View of porch piling and the well at site 968 

immediately after deployment; the well is at the base of the piling the farthest to the left in the picture. B, The well at 

site 968 strapped to piling shortly after deployment. C, View of porch piling with well completely buried just before 

recovering sensor from well. D, U.S. Geological Survey scientist digging out the well at site 968. 
15 

Figure 9. Atmospheric pressure time series from National Oceanic and Atmospheric Administration station 

DPIA1 and USGS measurements from an Onset Hobo U20 pressure sensor at site 965 on Dauphin Island, 

Alabama, in 2013. Although the study covered from July 22 through November 20, 2013, this graph only shows 

August 1 through October 1, 2013, to highlight the difference between the two sensors. dbar, decibars. 

Aug. 01, 2013 Sep. 01, 2013 Oct. 01, 2013

10

10.2

10.4

10.6

Atmospheric pressure (dbar)

DPIA1

Onset
16 

Figure 10. Atmospheric pressure and temperature time series from an Onset Hobo U20 atmospheric pressure 

sensor mounted on a residential porch railing at site 965 on Dauphin Island, Alabama, in 2013. dbar, decibars; °C, 

degrees Celsius. 

9.8

10

10.2

10.4

Pressure (dbar)

Jul. 23, 2013 Aug. 23, 2013 Sep. 23, 2013 Oct. 24, 2013

10

20

30

40

Temperature (C)
17 

Figure 11. Water-level time series from an RBR DR1060 pressure logger mounted in a buried well at site 966 on 

 

Jul. 23, 2013 Aug. 23, 2013 Sep. 23, 2013 Oct. 24, 2013

• 0.5

0

0.5

1

1.5

Water level (m, NAVD88)

Dauphin Island, Alabama, in 2013. m, meters; NAVD88, North American Vertical Datum of 1988. 

Jul. 23, 2013 Aug. 23, 2013 Sep. 23, 2013 Oct. 24, 2013

• 0.5

0

0.5

1

1.5

Water level (m, NAVD88)

Figure 12. Water-level time series from an RBR Virtuoso D|wave pressure logger mounted in a buried well at site 

968 on Dauphin Island, Alabama, in 2013. m, meters; NAVD88, North American Vertical Datum of 1988. 
18 

Jul. 24, 2013 Aug. 24, 2013 Sep. 24, 2013 Oct. 25, 2013

• 0.5

0

0.5

1

1.5

Water level (m, NAVD88)

Figure 13. Water-level time series from an Onset Hobo U20 pressure logger mounted in a buried well at site 

969 on Dauphin Island, Alabama, in 2013. m, meters; NAVD88, North American Vertical Datum of 1988. 

Jul. 24, 2013 Aug. 24, 2013

• 0.5

0

0.5

1

1.5

Water level (m, NAVD88)

Figure 14. Water-level time series from an RBR DR1060 pressure logger mounted in a buried well at site 970 on 

Dauphin Island, Alabama, in 2013. m, meters; NAVD88, North American Vertical Datum of 1988. 
19 

Jul. 24, 2013 Aug. 24, 2013 Sep. 24, 2013 Oct. 25, 2013

• 0.5

0

0.5

1

1.5

Water level (m, NAVD88)

Figure 15. Water-level time series from an RBR DR1060 pressure logger mounted in a buried well at site 971 on 

Dauphin Island, Alabama, in 2013. m, meters; NAVD88, North American Vertical Datum of 1988. 

Jul. 24, 2013 Aug. 24, 2013 Sep. 24, 2013

• 0.5

0

0.5

1

1.5

Water level (m, NAVD88)

Figure 16. Water-level time series from an RBR DR1060 pressure logger mounted in a buried well at site 972 on 

Dauphin Island, Alabama, in 2013. m, meters; NAVD88, North American Vertical Datum of 1988. 
20 

Jul. 24, 2013 Aug. 24, 2013 Sep. 24, 2013 Oct. 25, 2013

• 0.5

0

0.5

1

1.5

Water level (m, NAVD88)

Figure 17. Water-level time series from an Onset Hobo U20 pressure logger mounted in a buried well at site 973 

on Dauphin Island, Alabama, in 2013. m, meters; NAVD88, North American Vertical Datum of 1988. 

Jul. 25, 2013 Aug. 25, 2013 Sep. 25, 2013 Oct. 26, 2013

• 0.5

0

0.5

1

1.5

Water level (m, NAVD88)

Figure 18. Water-level time series from an Onset Hobo U20 pressure logger mounted in a buried well at site 974 

on Dauphin Island, Alabama, in 2013. m, meters; NAVD88, North American Vertical Datum of 1988. 
21 

Jul. 25, 2013 Aug. 25, 2013 Sep. 25, 2013 Oct. 26, 2013

• 0.5

0

0.5

1

1.5

Water level (m, NAVD88)

Figure 19. Water-level time series from an Onset Hobo U20 pressure logger mounted in a buried well at site 975 

on Dauphin Island, Alabama, in 2013. m, meters; NAVD88, North American Vertical Datum of 1988. 

Jul. 25, 2013 Aug. 25, 2013 Sep. 25, 2013 Oct. 26, 2013

• 0.5

0

0.5

1

1.5

Water level (m, NAVD88)

Figure 20. Water-level time series from an Onset Hobo U20 pressure logger mounted in a buried well at site 976 

on Dauphin Island, Alabama, in 2013. m, meters; NAVD88, North American Vertical Datum of 1988. 
22 

Tables Table 1. Mooring log sensor, location, and deployment information. [NAVD88, North American Vertical Datum of 1988; m, meter; N, north; W, west; UTC, Coordinated Universal Time; NA, not available] 

Sensor type Serial Number Site Sensor elevation, in m above NAVD88 

Sensor 

elevation 

uncertainty, in 

m above 

NAVD88 

Distance 

from cap to 

sensor, in m 

Latitude N Longitude W Time deployed, UTC Time rec

Onset Hobo U20-

001-04 

RBR DR1060 RBR DR1060 

RBR Virtuoso 

D|wave 

Onset Hobo U20-

001-01 

RBR DR1060 RBR DR1060 RBR DR1060 

Onset Hobo U20-

001-04 

Onset Hobo U20-

001-01 

Onset Hobo U20-

001-04 

Onset Hobo U20-

001-01 

10125471

24101 24032 

55033 

10313354 

24033 24099 24100 

10079949 10313355 10079950 10313353 

 965 

966 967 

968 969 

970 971 972 

973 974 975 976 

atmospheric, 

about 4 m 

-0.478 -0.873 

-1.18 

-0.269 -0.477 -0.490 -0.496 -0.501 -0.763 -0.585 -0.237 

NA 

0.008 

NA 

0.027 0.014 

0.031 0.014 0.036 

0.029 0.022 0.014 0.008 

NA 

0.819 

0.816 

1.463 0.678 

1.435 

1.43 

0.819 

1.24 

1.305 1.287 0.683 

30.25229 

30.25289 

30.25055 

30.24834 30.25213 

30.25019 30.24916 30.25232 

30.251 

30.24978 30.25164 30.25306 

88.15276 88.15424 88.19177 

88.19119 88.15872 

88.15273 88.17568 88.17518 

88.17506 88.19102 88.15425 88.15217 

7/22/13 15:15 

7/22/13 16:35 

7/22/13 21:10 

7/22/13 22:50 7/23/13 16:08 

7/23/13 17:00 7/23/13 20:15 7/23/13 21:25 

7/23/13 21:45 

7/24/13 0:58 

7/24/13 17:40 7/24/13 18:18 

11/20

11/19

Not r

11/1911/1911/1911/1911/19

11/1911/1911/1911/20
23 

Table 2. National Oceanic and Atmospheric Administration benchmarks on Dauphin Island, Alabama. 

[Benchmarks are near the entrance of Fort Gaines on the eastern side of Dauphin Island. Benchmark BH1755 is in North 

American Datum of 1983 coordinate system and bench

 Latitude 

BH1755 30 14 58.82004 

mark BH1755 is in World Geodetic System of 1984] 

Longitude 

88 4 33.67684 

Ellipsoid 

-25.167 

BH1755 30 14 58.83945 88 4 33.70183 -26.586 
24 

Table 3. Instrumentation and data files for measuring water levels, atmospheric pressure, and temperature at Dauphin Isla[UTC, Coordinated Universal Time; NA, not available] 

Sensor type Serial Number Site Start of data record, UTC End of data record, UTC Data file name 

Atmospheric pressure and temperature measurements 

Onset Hobo 10125471 965 7/22/13 15:20:00 11/20/13 21:20:00 9651hwl-a.nc 

Water-level measurements 

RBR DR1060 24101 966 7/22/13 16:35:00 11/18/13 8:46:28 9661rb-a.nc 

RBR DR1060 24032 967 NA NA NA 

RBR D|wave 55033 968 7/22/13 22:50:00 10/24/13 11:43:38 9681dw-a.nc 

Onset Hobo 10313354 969 7/23/13 16:10:00 11/19/13 21:50:00 9691hwl-a.nc 

RBR DR1060 24033 970 7/23/13 17:00:04 8/28/13 8:27:52 9701rb-a.nc 

RBR DR1060 24099 971 7/23/13 20:25:08 11/19/13 17:01:56 9711rb-a.nc RBR DR1060 24100 972 7/23/13 21:25:04 10/03/13 4:10:12 9721rb-a.nc 

Onset Hobo 10079949 973 7/23/13 22:10:00 11/19/13 19:30:00 9731hwl-a.nc 

Onset Hobo 10313355 974 7/24/13 01:00:00 11/19/13 17:30:00 9741hwl-a.nc 

Onset Hobo 10079950 975 7/24/13 17:50:00 11/19/13 15:00:00 9751hwl-a.nc 

Onset Hobo 10313353 976 7/24/13 18:30:00 11/20/13 21:50:00 9761hwl-a.nc 
ISSN 2331-1258 (online) 

http://dx.doi.org/10.3133/ofr20141245