current groundwater investigations at texas a&m university-corpus christi, rick hay
TRANSCRIPT
Current ground water investigations at Texas A&M
University-Corpus Christi
Richard Hay1, Dorina Murgulet2, Richard Coffin3, Valeriu Murgulet4,
1Assistant Director Center for Water Supply Studies, 2Assistant Professor of Geology TAMUCC, 3Department Chair Physical and Environmental Science TAMUCC, Research Associate Physical and Environmental Science TAMUCC.
Texas Alliance of Groundwater Districts – 10/30/2014
Outline• Water Resources and Climate
– Precipitation– Stream flow– Groundwater
• Ground water discharge to estuaries– Geophysics– Geochemistry– Hydrogeology
• Ground water discharge to Nueces River– Geochemistry– Geophysics– Hydrogeology
• Ground water/Surface water interaction– Thermal profilers– Geophysics
• Ground water and hydrocarbons– Stable Isotopes– C-Methane– C-Carbon dioxide
Texas Alliance of Groundwater Districts – 10/30/2014
Texas Alliance of Groundwater Districts – 10/30/2014
Climate
Texas Alliance of Groundwater Districts – 10/30/2014
South Texas Precipitation
• 200 meteorological stations.
• Spatial interpolation (kriging) to fill in missing data.
• Daily precipitation datasets 1890-2006
AUSTIN
SAN ANTONIO
CORPUS CHRISTI
BRYAN
LAREDO
MCALLEN
VICTORIA
ST. HEDWIG
ARANSAS PASS
BROWNSVILLE
Ü
Legend
Meteorological Stations
Urban Area
0 10050 Km
TEXAS
Study Area
JAN
FEBM
ARAPR
MAY
JUN
JUL
AUGSE
POCT
NOVDEC
0
200
400
600
800
1000
1200
Rai
nfa
ll (m
m)
Texas Alliance of Groundwater Districts – 10/30/2014
Climate Indicators
• ENSO – El Niño Southern Oscillation 2-4y • AMO – Atlantic Multidecadal Oscillation 20-40 y• PDO – Pacific Decadal Oscillation ~10-20y• MEI – Multivariate ENSO index 2-4y• Represent measureable phenomena that correlate
with weather patterns (climate).
Texas Alliance of Groundwater Districts – 10/30/2014
El Niño Southern Oscillation
• El Niño– wetter weather in Texas• La Niña – drier but more volatile weather
Texas Alliance of Groundwater Districts – 10/30/2014
Stream Flow
• Normalized Stream Flow – data compiled from 16 unimpaired USGS stream gages.
• Transformed from a time domain to frequency
• Wavelet transform – Change in frequency
over time
Strong signals at 12,
36-64, 128 months
Texas Alliance of Groundwater Districts – 10/30/2014
Ground Water
• Successful correlation of stream flow with climate indicators suggests that ground water resources may have a similar response to the climate “teleconnections”
• Currently developing an index similar to the normalized stream flow for ground water in south Texas.
Texas Alliance of Groundwater Districts – 10/30/2014
Ground Water Discharge to Bays
Submarine Groundwater discharge and hypoxia
• Using radon and resistivity to identify areas of ground water discharge that may be delivering nutrients to the bay.
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Hypoxic Plume
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Ground water flux to bay
• Figures 12-14: Oso Inlet time-lapse and difference conductivity inversions. (Note: Boxes represent source locations for SGD calculations and red dots indicate the location of Rn and conductivity monitoring, collected in sequence with the resistivity profiles)
D E F
Texas Alliance of Groundwater Districts – 10/30/2014
Changes in Rn and SC
• Time-lapse Radon (Rn) and conductivity data.
Texas Alliance of Groundwater Districts – 10/30/2014
Salinity in the Lower Nueces River
Texas Alliance of Groundwater Districts – 10/30/2014
Ground water discharge to the Nueces River
• Calallen Pool – Small impoundment from a salt water barrier dam where Corpus Christi and other entities take water from the Nueces River
1980 1990 2000 2010
10
02
00
30
04
00
Chlorides measured a 12964 (Bluntzer)
Sample Date
Ch
lori
de
s (
mg
/l)
missingdata
Increasing chloride concentration in the river water above the Calallen Pool.
Texas Alliance of Groundwater Districts – 10/30/2014
Specific Conductance v. Depth
• Specific conductance measurements show higher values at deeper depths
• Suggests ground water influence. Specific Conductance (uS)
De
pth
(m
)
0.5
1.0
1.5
2.0
2.5
3.0
0 5000
Run 01 Run 02
0 5000
Run 03 Run 04
0 5000
Run 05 Run 06
0 5000
Run 07
Run 08 Run 09 Run 10 Run 11 Run 12 Run 13
0.5
1.0
1.5
2.0
2.5
3.0
Run 14
0.5
1.0
1.5
2.0
2.5
3.0
Run 15
0 5000
Run 16 Run 17
0 5000
Run 18 Run 19
0 5000
Run 20 Run 21
Texas Alliance of Groundwater Districts – 10/30/2014
Calallen Pool and Hazel Basemore Park
• Location of monitoring wells
• Geophysical Transect
• Salt water barrier dam
Texas Alliance of Groundwater Districts – 10/30/2014
Soil conductivity survey at Hazel Basemore Park.
• Red indicates higher conductivity (saltier)
• Green indicates lower conductivity (fresher)
• Monitoring wells in agreement.
Texas Alliance of Groundwater Districts – 10/30/2014
Resistivity measurements
• Top panel resistivity array• Bottom panel magnetotelluric sounding• Red indicates high resistivity (fresher)• Blue indicates low resistivity (saltier)
MT x-section (ohm-m)
Distance (m)
Depth (m
)
50
100
150
50 100 150 200 250
Site.1
6
Site.2
1 Site.2
2
Site.2
0
Site.1
9
Site.1
8
Site.1
7
Site.1
5
Site.1
3
Min Coh = 0.7
Mean Coh = 0.936
1 2 3 4 5
Texas Alliance of Groundwater Districts – 10/30/2014
Resistivity along the river channel
• Fresher water in aquifer beneath river closest to the dam and furthest upstream
Texas Alliance of Groundwater Districts – 10/30/2014
Ground Water Flux• conversion of resistivity in ohm-ms (Ωm) to salinity in
parts per thousand (ppt):
S = 7.042 x Rp ¹· ²³³⁻ ⁰ (Manheim et al. 2004 )
Vgwr = Vsal* [(Sw-Sb)/Sb]* Sb (Dimova et al., 2012)
Base Station
Qsaline= 172.4 m3/dayQfresh= 65.7 m3/day
Texas Alliance of Groundwater Districts – 10/30/2014
Presence of Radon
• Surface water normally contains little or no radon (short half life, dissolved gas)
• Presence of radon in surface water indicates recent ground water discharge
Texas Alliance of Groundwater Districts – 10/30/2014
Ground Water – Surface Water
Texas Alliance of Groundwater Districts – 10/30/2014
Ground water - Surface water interaction using thermal and
geophysical techniques• Low gradient stream on coastal plain.• Time lapse resistivity measurements• Thermal profiler
Temperature Loggers
WELL PROFILER
WATER TABLE
Texas Alliance of Groundwater Districts – 10/30/2014
Data from Thermal Profilers
Jul Sep Nov Jan Mar May
10
15
20
25
30
Site SB-GW 08
Time
Te
mp
era
ture
(Ce
lciu
s)
Level 0 TemperatureLevel 1 TemperatureLevel 2 TemperatureLevel 3 TemperatureGroundwater
30
25
20
15
10
Jul Sep Nov Jan Mar May
Data collected over a 1 year period.
Texas Alliance of Groundwater Districts – 10/30/2014
Statistical Decomposition of Timeseries
• Random component represents period where vertical advection occured
Texas Alliance of Groundwater Districts – 10/30/2014
Time Lapse Resistivity
• Profile A and B were measured 2 months apart.
• C is the difference between the two measurements with the greatest change (red area) showing lateral discharge to the creek.
Texas Alliance of Groundwater Districts – 10/30/2014
Stable Isotopes
Texas Alliance of Groundwater Districts – 10/30/2014
Methane Source Assessment• 35 groundwater samples were collected from active
and non-active shale play areas to better define the extent of contamination and/or differentiate between methane sources (i.e. deep and shallow).
• δ13CCH4 and δ13CDIC values were measured to determine the range of signatures for shale petroleum-sourced methane and to differentiate between microbial and thermogenic methane sources.
Texas Alliance of Groundwater Districts – 10/30/2014
Results
• Both microbial and thermogenic methane (petroleum) were indicated in this preliminary study.
Texas Alliance of Groundwater Districts – 10/30/2014
Source Water• Deuterium• Oxygen• Meteoric line• Mixing• Heat
Thank You!
Questions?
Texas Alliance of Groundwater Districts – 10/30/2014
Contact:[email protected] (361)[email protected] (361)[email protected] (361)825-2456