Northern Segment of the Edwards Aquifer Study

SPRING 2014

Stephanie S. Wong and Joe C. Yelderman Jr.Baylor University, Geology Department

Tuesday, 11 February, 2014

Outline

1. Summary of summer 2013 dye trace study

2. Spring 2014 prioritiesi. Proposed Salado Spring dye trace

studyii. Instrumentationiii. Proposed Sanford Ranch dye trace

study

Completed: Summer 2013 Salado Creek dye trace test

• July 31st – August 1st • Injection at Stagecoach Inn Cave well– Uranine at 8:30 am– Eosine at 2:30 pm

• 15 monitoring sites along Salado Creek– Control: Robertson Plantation– Upstream: 2 sites– Downstream: 12 sites

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

5.50

6.00

6.50

7.00

7.50

8.00

8.50

9.00

9.50

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

160.00

Time elapsed (hours)

Co

nce

ntr

ati

on

(p

pb

)

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

0123456789

Time elapsed (hours)

Co

nce

ntr

ati

on

(p

pb

)

EOSINEURANINE

Findings• There appears to be groundwater discharge

across the creek from Big Boiling Spring.

• All the springs seem to be connected and function as an integrated system under low-flow conditions. – This supports the conclusion from USGS chemistry

results.– Managing the springs using the flow gage below

the springs appears reasonable.

• Flow from the Stagecoach Inn Cave well does not flow to Robertson Spring or upstream from Little Bubbly under low-flow conditions.

Proposed: Spring 2014 Salado Creek dye trace test

• PURPOSE: To study the Salado springs system under higher-flow conditions

• OBJECTIVES: – Replicate summer trace test

under (injection point, monitoring locations)

– Refine sampling and monitoring

– Add monitoring locations

New monitoring locations

• Robertson Spring• Little Bubbly• Salado Patio well?• Cemetery well

Little Bubbly spring run (Jan. 2014)

Refine monitoring

• Refine amount of dye used – Less uranine, more eosine

• Two Isco automated samplers if possible– Big Boiling springs – one fracture– Anderson spring– Extend sampling time to

catch tail

• Employ larger field teams

Conce

ntr

ati

on

Time

TAIL

PEAK

FIRST ARRIVAL

North bank groundwater discharge

Salado Creek

Big Boiling Springs

?

?

• Source direction is unclear……

• Inject dye from north bank– Different dye

• Injection point:– Existing point, OR– Auger new hole

Instrumentation

• Budgeted:–Weather stations (2-4) - $3000– Rain gauges (15) - $450– Data loggers (3) - $6000– Flumes and weirs (2-4 as needed) -

$6000

Gault Site

Patterson’sCrossing

Rest-Stop well

Cemetery well

Datalogger

Weather station

Future: Sanford Ranch dye trace test

• PURPOSE: To study groundwater flow and connectivity in a wider study area in the Northern Segment of the Edwards Aquifer

Questions?