Upload
lamtruc
View
213
Download
1
Embed Size (px)
Citation preview
Springs and recharge in the Northern Segment of the Edwards Balcones Fault Zone aquifer
Stephanie S. Wong and Joe C. Yelderman Jr.Department of Geology | Baylor University | One Bear Place #97354 | Waco TX 76798
Presented at the 15th Annual Bell County Water SymposiumThursday, November 19, 2015 || Belton, Texas
Presentation outline
• Setting• Milestones and research
activities, 2011-2015• Ongoing and future work• Lessons learned
Our purpose today:Step through time and revisit milestones of Edwards
aquifer study
2
Northern Segment
Barton Springs Segment
San Antonio Segment
Setting: The Edwards BFZ Aquifer
SALADO
SAN ANTONIO
AUSTIN
(I-35 CAC, 2011) 3
Study area: Salado Springs complex
Big BoilingSpring
Anderson Spring
Critchfield Spring
Doc Benedict Spring
Little Bubbly Spring
USGS stream gage
Big Boiling spring
Anderson spring
Critchfieldspring
Edwards aquifer research through time
2011
• The Epic Drought• Beginning of
Baylor relationship with Clearwater
5
Recent Drought
2011
http://droughtmonitor.unl.edu
Abnormally dry
Moderate drought
Severe drought
Extreme droughtExceptional drought
6
Edwards aquifer research through time
2011
2012
• Salado salamander proposed to be listed as endangered
7
Salado Salamander, Eurycea chisolmensis
Big BoilingSpring
Anderson Spring
Critchfield Spring
Doc Benedict Spring
Little Bubbly Spring
USGS stream gage
Salado Salamander
• Fully aquatic – restricted to water-filled openings, or near spring outflows
• Endemic to the Salado Springs system
Edwards aquifer research through time
2011
2012
2013
• Research contract with Baylor
• Dye tracer test (summer)
9
Why should we study the Edwards aquifer?
• Not well-studied• Important as water
source and habitat• Local groundwater
management measure
• Continued growth in the area– What are impacts of
development on aquifer? 0
50,000
100,000
150,000
200,000
250,000
300,000
350,000
201320101990198019701960
Popu
latio
n
(United States Census Bureau, 2015)
2013: 326,843
Bell County Population
Salado springs
DFC: Minimum 100 ac-ft /
month
10
Collaboration with CUWCD: objectives
• To improve our understanding of the Northern Segment of the Edwards Aquifer,
– Research– Monitoring
• to communicate research results and scientific knowledge with project partners and stakeholders,
– Regular communication with CUWCD– Presentations
• so that management of the Northern Segment for water resource and critical habitat can be better informed
11
Research program design for CUWCD
• System characterization:– Measuring well water levels– Dye tracing– Dissolved radon concentrations– Recharge feature characterization
• Monitoring:– Stream cross sections– Multi-parameter dataloggers
• Long-term deployments• Event-based deployments
– Weather stations
FOCUS AREAS:• Instrumentation• Build knowledge
base• Field tests and
feasibility studies12
Measuring synoptic water levels
13
Groundwater elevations, 2013
600
n = 39
SALADO
14
2010-2013 comparison
400
450
500
550
600
650
700
750
800
850
Wat
er le
vel e
leva
tion
(ft)
Well pair
2010 2013
01 0302 0504 06 07
?
==
Average change = +1 ft
15
Dye tracing
• Tracks water flow paths
• Use of particles or chemical
Spring connectivity: Dye tracing
Critchfield
Stagecoach Inn Cave
USGS Gage
Side sp.
Big Boiling upstream
Low Water Dam
Big Boiling
AndersonDoc Benedict
Rock sp.
Pace ParkRobertson sp.
upstreamRobertson sp.
(outlet 1) Robertson sp.(outlet 2)
SymbolsCave well
Surface waterSpringC O N T R O L
C O N N E C T I O N ?
Mahler et al., 1998:• Well to Big Boiling Sp.
(~800 ft)• Lanthanide-tagged clay
(particle trace)
??
17
Summer 2013 trace
Critchfield
Stagecoach Inn Cave
USGS Gage
Side sp.
Big Boiling upstream
Low Water Dam
Big Boiling
AndersonDoc Benedict
Rock sp.
Pace Park
Robertson sp.(outlet 2)
Summer 2013 trace results
DETECTIONTime elapsed
(hrs)Big Boiling
First: 1.8Peak: 2.7
Big Boiling
Anderson
18
Edwards aquifer research through time
2011
2012
2013
2014
• Salado salamander listed as threatened
• Research permit• Instrumentation
19
Summer 2014 field work
• ~30 sites visited; 20 sites sampled
• Sampled:– Water level– pH, temperature, specific
conductance– Dissolved nitrates, phosphates,
organic carbon– Nitrogen isotopes– Radon
• Lessons learned:– Site suitability
Gifford
Goode Towing
Broeker Funeral Home
ThalerBartlett
Salado ISD
Big Boiling Sp.
Daybreak
Tenroc 2
Tenroc 1Coppin
Bloomer
Owens
Peters
Capps
Little D.
Eastland W.
Salado QuarriesGault site
Stowe
Summer 2014 sample locations
21
Monitoring recharge: Weather stations
Station 1(since spring 2014)
Station 2(since fall 2014)
Station 3(since fall 2014)
0
0.02
0.04
0.06
0.08
0.1
0
20
40
60
80
100
Rai
n (in
)
Tem
pera
ture
(°F)
0
0.2
0.4
0.6
0.8
1
0
20
40
60
80
100
Rai
n (in
)
Tem
pera
ture
(°F)
00.10.20.30.40.50.60.7
0
20
40
60
80
100
Rai
n (in
)
Tem
pera
ture
(°F)
June 15-20, 2015
22
SaladoHidden Springs
Gault Site
Potential areas for additionalRain gauges
23
Edwards aquifer research through time
20152011
2012
2013
2014
• Ongoing research
• Dye tracer test (spring)
24
Spring 2015 trace
Critchfield
Stagecoach Inn Cave (injection)
USGS Gage
Side sp.
Big Boiling upstream
Low Water Dam
Big Boiling
AndersonDoc Benedict
Rock sp.
Pace ParkRobertson sp.
upstreamRobertson sp.
(outlet 1) Robertson sp.(outlet 2)
Big Boiling
Anderson
DETECTIONTime elapsed
(hrs)Big Boiling
First: 0.26Peak: 1.5
25
300
350
400
450
500
550
600
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Spec
ific
cond
ucta
nce
(S/
cm)
Distance from south bank (feet)
North bank groundwater discharge
= Sept. 21, 2013 = April 19, 2014
Upstream of Big Boiling
Downstream of Big Boiling
Big Boiling spring run
Groundwater
StreamflowSalado Creek
Big Boiling Springs
S a l a d o C r e e k
Big Boiling Springs
?
? Dye detection
26
14 ft
March 28, 2015:Installing piezometer caused sediment discharge from Rock spring.
July 2, 2015:
Rock spring outlet buried by gravel.
• July: 504 µS/cm• Sept.: 601 µS/cm
27
Multi-parameter monitoring
• Three parameters:– Water level change– Temperature– Specific Conductance
• Long-term monitoring and event-based monitoring
Long-term monitoring atStagecoach Inn Cave
(since May 2013)
Event-based monitoring
28
29
68.90
69.00
69.10
69.20
69.30
69.40
69.50
69.60
69.70
69.80
69.90
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
Tem
pera
ture
(°F)
Wat
er le
vel (
ft ab
ove
sens
or)
Spec
ific
cond
ucta
nce
(µS/
cm)
650
640
630
620
610
600
590
570
580
550
560
Stagecoach Inn cave well, May 2015
30
68.90
69.00
69.10
69.20
69.30
69.40
69.50
69.60
69.70
69.80
69.90
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
Tem
pera
ture
(°F)
Wat
er le
vel (
ft ab
ove
sens
or)
Spec
ific
cond
ucta
nce
(µS/
cm)
650
640
630
620
610
600
590
570
580
550
560
Stagecoach Inn cave well, May 2015
31
68.90
69.00
69.10
69.20
69.30
69.40
69.50
69.60
69.70
69.80
69.90
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
Tem
pera
ture
(°F)
Wat
er le
vel (
ft ab
ove
sens
or)
Spec
ific
cond
ucta
nce
(µS/
cm)
650
640
630
620
610
600
590
570
580
550
560
Stagecoach Inn cave well, May 2015
400420440460480500520540560
Spec
ific
cond
ucta
nce
(S/
cm)
Anderson sp.
400420440460480500520540560
Spec
ific
cond
ucta
nce
(S/
cm)
Time
Doc Benedict sp.
Specific conductance, April 14-30, 2015
Cave well
1. Separate fractures from cave to springs?
2. One major fracture to Anderson with branch-off to Doc B.?
30
Edwards aquifer research through time
20152011
2012
2013
2014
There is still much to learn!
33
Ongoing research and future work
• Continue monitoring and data collection– New sensor: nitrate data– Thermal imagery
• Refine field tests and sampling• Analysis and interpretation of collected data
– Monitoring data (dataloggers, weather stations)– Recharge features
32
Recharge features analysis
• Objectives:– Identify lineations and
depressions using LiDAR data
– Differentiate between geologic and anthropogenic lineations and depressions
– Identify geologic lineations and depressions that are potential recharge features
Field reconnaissance of karst features(February 2015)
35
0.5 0.25 0 0.5 Miles
N
I-35
Losing stream section,Stanford Ranch
LiDAR point cloud
1.
Elevation (masl)
198.425
193.937
1 x 1 m DEM
2.
193.937 – 194.065
194.065 – 194.146
194.146 – 194.276
194.276 – 198.425
Elevation (masl)Extracted pixels
3. 36
Fractures Sinkholes
Caves Losing streams 37
Thermal imagery
• FLIR - High-performance infrared imaging
• Spatial data calibrated to other water data (chemistry, flow etc.)
• Potential relevance:– Groundwater/surface
water interactions– Habitat delineation – Advancing science
36
New knowledge
• Water levels have not greatly declined, even through Epic Drought
• Baseline chemistry of groundwater and surface water established
• Clear difference in chemistry between groundwater and surface water at Salado Springs
• Identification of groundwater discharge points that are not official springs
• Confirmation that all springs in Salado Springs complex are connected
• Aquifer response to recharge events
37
Key to success?
38
People!
• Collaboration and communication • Everyone has valuable knowledge;
everyone wants to learn• Many hands make light work• Access to sites• Foundation for follow-up work
39
Management contributions
• Stream gauge location is suitable for aquifer monitoring
• Aquifer study important to listing process of Salado Salamander
• As development in the area continues, a monitoring program builds baseline for aquifer conditions– Facilitates change detection– Prepares managers to assess, respond to, and manage aquifer
impacts
Proposed to be listed in 2012Listed as threatened in Feb. 2014
40