Dye tracing results from the Arbor Trails Sinkhole, Barton Springs segment of the Edwards Aquifer, Austin, Texas

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Dye tracing results from the Arbor Trails Sinkhole, Barton Springs segment of the Edwards Aquifer, Austin, Texas

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Dye tracing results from the Arbor Trails Sinkhole, Barton Springs segment of the Edwards Aquifer, Austin, Texas
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BSEACD Report of Investigations 2013-0501
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Barton Springs/Edwards Aquifer Conservation District
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Barton Springs (Austin, Texas, United States) ( 30.263819, -97.771395 )
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United States
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30.263819 x -97.771395

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ABSTRACT On January 24, 2012, a 4.5 inch rainfall filled a Storm Water Retention Pond (SWRP) located in the recharge zone of the Barton Springs segment of the Edwards Aquifer with about 10 feet of stormwater. Subsequently, a cover-collapse sinkhole developed within the floor of the SWRP, measuring about 30 ft in diameter and 12 ft deep. About 7 million gallons of stormwater drained into the aquifer through this opening. To determine the path, velocity, and destination of stormwater entering the sinkhole, a dye trace was conducted. Phloxine B was injected into the sinkhole on February 3, 2012. The dye was detected at one well and arrived at Barton Springs in less than 4 days, corresponding to a minimum velocity of 1.3 mi/day. The successful dye trace confirmed conclusions of previously published reports by demonstrating that the sinkhole is well integrated into the aquifer system, and that groundwater in the study area is within the Sunset Valley Groundwater Basin. Phloxine B proved to be a very good, conservative tracer through the collapsed terra rosa material of the sinkhole.
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ABSTRACT On January 24, 2012, a 4.5 inch rainfall
filled a Storm Water Retention Pond (SWRP) located in the
recharge zone of the Barton Springs segment of the Edwards
Aquifer with about 10 feet of stormwater. Subsequently, a
cover-collapse sinkhole developed within the floor of the
SWRP, measuring about 30 ft in diameter and 12 ft deep. About
7 million gallons of stormwater drained into the aquifer
through this opening. To determine the path, velocity, and
destination of stormwater entering the sinkhole, a dye trace
was conducted. Phloxine B was injected into the sinkhole on
February 3, 2012. The dye was detected at one well and
arrived at Barton Springs in less than 4 days, corresponding
to a minimum velocity of 1.3 mi/day. The successful dye trace
confirmed conclusions of previously published reports by
demonstrating that the sinkhole is well integrated into the
aquifer system, and that groundwater in the study area is
within the Sunset Valley Groundwater Basin. Phloxine B proved
to be a very good, conservative tracer through the collapsed
terra rosa material of the sinkhole.



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Dye Tracing Results from the Arbor Trails Sinkhole, Barton Springs Segment of the Edwards Aquifer, Austin, Texas BSEACD Report of Investigations 2013 0 5 01 May 2013 Barton Springs/Edwards Aquifer Conservation District 1124 Regal Row Austin, Texas

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BSEACD Report of Investigations 2013 0501 i | Page Di sclaimer All of the information provided in this report is believed to be accurate and reliable; however, the any errors or for the use of the information provided. Cover Phloxine B dye injection at Arbor Trails sinkhole. Dye was injected on February 3, 2012 at about 13:00. A mass of 16.27 lbs (7,382g) was mixed with water and then gravity injected via a hose using storm water from an ad jacent pond. (see Figure 7).

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BSEACD Report of Investigations 2013 0501 ii | Page Dye Tracing Results from the Arbor Trails Sinkhole, Barton Springs Segment of the Edwards Aquifer, Austin, Texas Brian B. Hunt, P.G., Brian A. Smith, Ph.D., P.G., Kendall Bell Enders, John Dupnik, P.G., and Robin Gary Barton Springs/Edwards Aquifer Conservation District Steve Johnson, P.G. Edwards Aquifer Authority Nico M. Hauwert, Ph.D., P.G., and Justin Camp City of Austin Watershed Protection Department BSEACD General Manager Kirk Holland, P.G. BSEACD Board of Direc tors Mary Stone, President Precinct 1 Gary Franklin, Vice President Precinct 2 Blake Dorsett Precinct 3 Dr. Robert D. Larsen Precinct 4 Craig Smith, Secretary Precinct 5 BSEACD Report of Investigations 2 013 0 501 May 2013 Barton Springs/Edwards Aq uifer Conservation District 1124 Regal Row Austin, Texas

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BSEACD Report of Investigations 2013 0501 iii | Page CONTENTS Introduction 1 Dye Tracing Methods 9 Results 13 Discussion 1 7 Conclusions 1 7 References 1 8 Appendi ces 1 9 Table 1. Chemical Characteristics of Dy es Table 2. Reported Detection Limits for Phloxine B Table 3. Sites monitored and results Figure 1 Location map of the study area. Figure 2. Summary of previous dye tracing in the area and the delineation of groundwater basins. Figure 3. Predevelopme nt topographic map. Figure 4. Detailed site map with key elements of the stormwater retention pond (SWRP), sinkhole location, a nd 2012 geophysics and boreholes. Figure 5. H ydrograph showing rainfall, streamflow, and Barton Springs flow with conductivity a nd turbidity. Figure 6. Photograph s of sinkhole, all photos facing north. A) photo taken the day the sinkhole was observed B) Photo taken two days after collapse and prior to excavation. C) Photo showing solutioned fracture in bedrock overlain by terra rosa and clay liner. Figure 7. Phloxine B dye injection at Arbor Trails sinkhole. Figure 8. Phloxine B breakthrough graphs from the study. Figure 9. Map of results from the Arbor Trails dye trace.

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BSEACD Report of Investigations 2013 0501 1 | Page Dye Tracing Results from the Arbor Trails Sinkhole, Bar ton Springs Segment of the Edwards Aquifer, Austin, Texas Brian B. Hunt, P.G., Brian A. Smith, Ph D. P.G., Kendall Bell Enders, John Dupnik, P.G. and Robin Gary Barton Springs/Edwards Aquifer Conservation District Steve Johnson, P.G. Edwards Aquifer Aut hority Nico M. Hauwert Ph.D., P.G., and Justin Camp City of Austin Watershed Department ABSTRACT On January 24, 2012, a 4.5 in ch rainfall filled a Storm Water Retention Pond ( SWRP ) located in the recharge zone of the Barton Springs segment of the Edward s Aquifer with about 10 f ee t of stormwater. Subsequently, a cover collapse sinkhole developed within the floor of the SWRP measuring about 30 ft in diameter and 12 ft deep. About 7 million gallons of stormwater drained into the aquifer through this openin g. To determine the path, velocity, and destination of stormwater entering the sinkhole a dye trace was conducted. Phloxine B was injected into the sinkhole on February 3, 2012. The dye was detected at one well and arrived at Barton Springs in less tha n 4 days corresponding to a minimum velocity of 1.3 mi/day. The successful dye trace confirmed conclusions of previous ly published reports by demonstrating that the sinkhole is well integrated into the aquifer system, and that groundwater in the study are a is within the Sunset Valley Groundwater Basin. Phloxine B proved to be a very good conservative tracer through the collapsed terra rosa material of the sinkhole. INTRODUCTION Sudden cover collapse sinkhole (doline) development is uncommon in the karstic Cretaceous age Edwards limestone of central Texas. On January 24, 2012, a 4.5 in rainfall filled a Storm Water Retention Pond ( SWRP ) located in the recharge zone of the Barton Springs segment of the Edwards Aquifer, with about 10 ft of stormwater. Subse quently, a sinkhole developed within the floor of the SWRP measuring about 30 ft in diameter and 12 ft deep. About 7 million gallons of stormwater drained into the aquifer through this opening The sinkhole is located on a commercial development property called Arbor Trails and hereafter is referred to as the Arbor Trails Sinkhole (ATS). The property is located southwest of the intersection of William Cannon Dr. and MoPac (Loop 1) within the recharge zone of the Barton Springs segment of the Edwards Aqui fer ( Figure 1 ).

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BSEACD Report of Investigations 2013 0501 2 | Page Figure 1. Location map of the study area. Indicated are the Brush Country well (BC well) and a USGS stream gage station on Williamson Creek. The ATS is located near a groundwater basin divide (Cold Springs and Sunset Valley basins) de fined by previous studies and dye tracing by Hauwert et al., 2004 ( Figure 2 ) The purpose of the dye trace is to understand whether water that entered the ATS flowed north to Cold Springs, or northeast to Barton Springs. Understanding groundwater flow in the area is important as it contains relatively dense urban development with large highways and roads that could be potential source s of contaminants Understanding the flow routes can help agencies notify existing groundwater users and to know which sprin g would be impacted in the event of a spill Barton Springs is a major recreational destination for

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BSEACD Report of Investigations 2013 0501 3 | Page the City of Austin and is habitat for the e ndangered Barton Springs s alamander. The ATS provided an opportunity to trace groundwater flow and better delinea te and define groundwater flow in the area. The dye trace study was conducted by the Barton Springs / Edwards Aquifer Conservation District (District) and the City of Austin (CoA). District staff injected 16.3 lbs of Phloxine B dye into the ATS on February 3, 2012. The dye was detected at one well and Barton Springs within a few days. Results of the trace indicate rapid groundwater flow from the injection site to Barton Springs and confirms that the area is part of the Sunset Valley Groundwater basin as pr evious ly defined by Hauwert et al., 2004. This report documents the dye trace study conducted at this feature. The reader is referred to Hunt et al., 2013 to learn more about the ATS and its mitigation Previous Work Previous groundwater dye tra cing studi es that established major flow paths and also groundwater basins within the aquifer were published by Hauwert et al., 2004. The ATS is located near a groundwater divide between the Cold Spri ngs and Sunset Valley basins Whirlpool Cave is located 0.5 miles southwest of the ATS. In 1999 5 lbs of Eosine dye were traced from Whirlpool Cave to Upper and Main Barton Springs in 3 4 days. In 1997 10 lbs of Rhodamine WT (RWT) were injected into a monitor well located in the middle of Williamson Creek (BC well, Fig ure 2 ) which is located 0.5 miles north of the ATS. Dye arrived from the BC well at Cold Springs in less than 8 days (Hauwert et al., 2004). These two features, along with other traces and data, helped define the groundwater basins known as the Cold Spri ngs and Sunset Valley Groundwater Basins ( Figure 2 ). Figure 2. Summary of previous dye tracing in the area and the delineation of groundwater basins. Note the Arbor Trails Sinkhole is located very close to the estimated groundwater divide between the Col d S prings and Sunset Valley basins. WC is whirlpool cave and BC is Brush Country Well.

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BSEACD Report of Investigations 2013 0501 4 | Page Setting The ATS is located wi thin the recharge zone of the Barton Springs segment of the Edwards Aquifer (Figures 1 and 2). The 72 acre property was developed in accor Development Code and the State of Texas requirements (Chapter 213 Edwards Rules). Review of topographic contours from the City of Austin 2 ft contour maps dated 1981 prior to MoPac (Loop 1) reveals a very shallow and large (6 acre) depression centered on the SWRP (Figure 3). The contours are present but more subtle on the 10 ft contour USGS q uadrangle m ap of the area. The area appears well drained with no ponded water features evident in the aerial photos, and hardwood tree s are present. However, the subdued nature of the feature and the subsequent disturbance from the highway that bisected the eastern portion of the depression made detection of the feature in the field difficult. As part of the site engineering studies, g eotechnical cores and borings were conducted throughout the site. I the p reliminary geotechnical studies, 6 m (20 ft) deep cores were collected near the ATS (B 8 and B 9; Figure 3 ). The core holes and borings extended to the same depth as the final SWRP ex cavation depth. Both cores returned rock quality designation (RQD) of very poor to incompetent rock. Both cores indicated lost fluids within the first 10 feet and solution channels and small voids (HBC/Terracon, 2005), consistent with epikarst. The locatio n of the SWRP for the Arbor Trails development is shown in Figure 4. The purpose of the SWRP is to capture storm runoff from impervious areas (buildings and parking lots) and then irrigate vegetative areas throughout the property with the stormwater. Th e SWRP consists of two water quality controls : a geomembrane lined wet pond inset within a compacted clay lined retention pond. The wet pond has a forebay and main permanent pool area that are separated by a berm. The wet pond was constructed for aestheti cs within the retention basin. The retention pond has its capture volume above the permanent pool elevation for the wet pond. The capture volume for the retention pond extends up 6 ft onto the slope areas of the basin. The retention pond is the actual perm itted water quality control structure for the surrounding shopping center. During a rain event stormwater captured by the retention basin is held and then used to irrigate vegetated areas th roughout the property within 72 hours.

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BSEACD Report of Investigations 2013 0501 5 | Page Figure 3 Predevelopm ent topographic map. Basemap is USGS Oak Hill Quadrangle (10 ft contours in brown). Geologic information from HBC/Terracon (2004) and likely sourced from Small et al., 1996 Black lines are City of Austin 2 ft topographic contours dated 1981, prior to ma jor highway construction (MoPac). Contours create a depression centered around the SWRP, shown as dashed lines.

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BSEACD Report of Investigations 2013 0501 6 | Page Figure 4 Detailed site map with key elements of the stormwater retention pond (SWRP), sinkhole location, a nd 2012 geophysics and boreholes. Hydrologic Conditions and Sinkhole Collapse Prior to collapse of the ATS, central Texas had been experiencing a severe drought. Beginning in late January, rainfall and subsequent recharge brought the aquifer out of drought conditions. Figure 5 illustrates the rainfall, runoff, and response of wells and springs to the recharge. On January 24, 2012 a 4.5 in rainfall event occurred in the area of the Arbor Trails development filling the SWRP with about 10 ft of water. On January 25, 2012 maintenance crews noticed the pond was draining into a developing sinkhole ( Figure 6 a ). The size of the sinkhole was about 30 ft in diameter and 12 ft deep. About 7 million gallons of storm water drained into the aquifer through this opening. It is possible the drought and desiccation of the clay liner in the pond contributed to the compromise of the SWRP and development of the sinkhole. A significant increase in turbidity at Barton Springs is associated with the late January rainfall (and March rainfall ; Figure 5 ). These types of increases are relatively common in this karst system. District staff observed the runoff and recharge into swallets (Brodie Cave) within nearby tributaries of Slaughter

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BSEACD Report of Investigations 2013 0501 7 | Page Creek from the same rainfall event that triggered the collapse of the ATS. It was noted that the stormwater entering those features was very turbid. Accordingly, the jump in turbidity cannot be solely attributed to the failure of the SWRP. After the collapse, the sinkhole was further characterized by ACI Consulting (Austin, T X) thr ough excavation, surface geo physics, and borehole drilling These studies are discussed in Hunt et al. ( 2013 ). The ATS was excavated to a total depth of 21 feet Most of the geologic material in the sinkhole consisted of friable, highly altered (weathered) clayey limestone and terra rosa, an iron rich clay soil Very little competent bedrock was encountered in the excavations. Solution fractures in the ATS were observed to have a NNE strike. Steep (~30 degree) west dipping limestone beds in the ATS and alo ng strike behind the northern retaining wall were observed ( Figure 6 ) The highly altered, fracture d, and dipping nature of the rock s along stri k e supports the presence of the inferred mapped fault zones ( Figure 3 ). Figure 5: H ydrograph showing rainfa ll, streamflow, and Barton Springs flow with conductivity and turbidity. Time of s inkhole collapse and dye injection indicated

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BSEACD Report of Investigations 2013 0501 8 | Page Figure 6 Photograph s of sinkhole, all photos facing north. A) photo taken the day the sinkhole was observed (credit Heather Beatty, TCEQ). B) Photo taken two days after collapse and prior to excavation. Note the limestone beds are dipping to the west. C) Photo showing solutioned fracture in bedrock overlain by terra rosa and clay liner.

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BSEACD Report of Investigations 2013 0501 9 | Page DYE TRACING METHODS Groundwater dye traci ng involves the introduction of non toxic, organic dyes into the subsurface via injection points, such as caves, sinkholes, and wells, and analyzing charcoal receptors and water samples taken from discharge points such as wells and springs. Alexander and Quinlan (1992) and Alley (1999) discuss the methodology of groundwater tracing with dyes. Groundwater Tracers (Phloxine B) Phloxine B dye used in this study was selected because it is nontoxic, inexpensive, widely tested and used, and easily detected by its fluorescence The dye has been evaluated to be suitable for this and other studies due to its physical characteristics, safety for drinking water supplies and aquatic habitats, and low background concentrations (Smart, 1984; Field et al., 1995). Phl oxine B has been used extensively in the San Antonio segment of the Edwards Aquifer (Johnson et al. 2012 ), but it has not been used in the Barton Springs segment. Table 1 lists the molecular weight and emission wa velength of Phloxine B The amount that was injected was consistent with previous injections (Hauwert et al., 2004) for the given location, distance, and hydrologic conditions. In addition, few public water supply systems are located along the expected flo w paths, so that visible concentrations were less of a concern. Table 1. Chemical Characteristics of Dyes Common Name Color Index Generic Name Molecular Weight CAS Number Emission Wavelength (nm) Phloxine B Acid Red 92 829.63 18472 87 2 541 from Johns on et al., (2012 ) Injection A mass of 16.3 lbs (7,382 grams) of Phloxine B Dye was injected on February 3, 2012 at about 13:00. The dye was in powder form and was mixed with water at the ATS site The dye solution was mixed with w ater from the adjacent s torm water pond and gravity injected into the sinkhole with a hose and PVC pipe that was placed in the bottom of the sinkhole where the dye solution infiltrated. About 5,000 gallons of water was pumped from the adjacent storm water pond to flush the dye i nto the feature ( Figure 7 ).

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BSEACD Report of Investigations 2013 0501 10 | Page Figure 7 Phloxine B dye injection at the Arbor Trails S inkhole. Dye was injected on February 3, 2012 at about 13:00. A mass of 16.27 lbs (7,382g) was mixed with water and then gravity injected via a hose using storm water from an adjacent pond.

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BSEACD Report of Investigations 2013 0501 11 | Page Sampling Samples were collected by the District and CoA during the course of this study. Staff who injected the dye were not involved in sample collection. Sampling supplies were provided by the respective labs, and sampling procedu res outlined by Ozark Underground Labs ( OUL ) were followed (Aley, 1999; Hauwert et al., 2004). Field control samples were carried by staff collecting samples. Spring sampling locations were monitored by the City of Austin and include d Barton Springs (Mai n, Eliza, Upper, and Old Mill spring outlets) and Cold Springs ( Figure 2 ). From 2/3/12 to 3/5/12 t en wells were monitored by the BSEACD weekly for the presence or absence of dyes in groundwater using charcoal samples ( Table 3 ). No background charcoal sam ples were in place prior to injection. Barton Springs sites were monitored from 2/2/12 to 3/13/12 with charcoal receptors. No background receptors were in place prior to injection. However, grab samples taken on 2/2/12 were non detect for Phloxine B. Aft er injection of the dye, charcoal receptors were collected approximately daily beginning 2/7/12. Grab samples were taken when receptors were changed. In addition, water samples were taken from an ISCO 3700 Automatic Compact Sampler at 4 to 8 hour interva ls at Upper Barton Springs from 2/7/12 to 2/25/12. Charcoal and grab samples from Cold Springs were collected weekly between 2/3/12 and 3/13/12. No background receptors were in place at C old Springs prior to injection, but water samples collected on 2/3/ 12 were non detect for Phloxine B. Laboratories Receptors and grab samples from springs were analyzed at the Edwards Aquifer Authority (EAA) and replicate samples were analyzed at OUL in Missouri. Detection limits are provided in Table 2 Below is a brie f na rrative of each laborator methods. Table 2 Reported D etection Limits for Phloxine B Water Detection Limit (ug/L or ppb) Charcoal Detection Limit (ug/L or ppb) EAA 0.044 0.044 OUL 0.004 0.004 Edwards Aquifer Authority For analyses at the EAA d ye was extracted from charcoal receptors prior to analysis by eluting the charcoal (desorbing the dye) for one hour in a solution containing 95% of a 70% solution of 2 propanol in water and 5% sodium hydroxide. Phloxine B in vials and eluents from charcoal were analyzed in the laboratory with a Perkin Elmer LS 50B Luminescence Spectrometer using synchronous scan and right angle sampling geometry. The scan spanned 401 to 650 nm at 0.5 nm intervals (covering Eosine, Uranine, and Phloxine B) with a difference between excitation and emission wavelengths (delta lambda) of 15 nm and emission and excitation slits set at 6 nm (see Narrative Appendix 1 ) Results of the analysis are recorded in intensity units and converted to concentrations by comparison with known standards. Three standards were prepared for each of the three dyes detected in the tracer tests. Dye solutions were prepared on the basis of mass and diluted with deionized water filtered

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BSEACD Report of Investigations 2013 0501 12 | Page through a 0.2 micron filter to produce dye concentrations in the r ange that were e xpected in the water samples (see Narrative Appendix 1 ) Detection limits for each dye were calculated from background fluorescence of naturally occurring fluorophores and instrument noise, following the method of Alexander (2005). The met hod defines limits of detection (LOD) and quantitation (LOQ) as three and ten times the fit standard error of background fluorescence, respectively. Water samples were selected that contained dyes at concentrations just above background fluorescence to cal culate LOD and LOQ, and fit standard error was calculated using peak fitting software (see Narrative Appendix 1 ) Ozark Underground Labs OUL does not routinely analyze for Phloxine B dye. However, the lab did the analyses and followed procedures establishe d for the analyses of other dyes (such as Pyranine). OUL elutes charcoal in a mixture of 5% aqua ammonia and 95% isopropyl alcohol solution and sufficient potassium hydroxide flakes to saturate the solution for most dyes. The isopropyl alcohol solution is 70% alcohol and 30% water. The aqua ammonia solution is 29% ammonia. The potassium hydroxide is added until a super saturated layer is visible in the bottom of the container. Fifteen ml of the eluting solution is poured over washed charcoal in a disposable sample beaker. The sample beaker is capped, allowed to stand for 60 minutes, and then the liquid is carefully poured off the charcoal into a new disposable beaker which has been appropriately labeled with the laboratory identification number (Aley, 2008). OUL analyzes water and eluent samples on one of two Shimadzu spectrofluorophotometers: model RF 5000U or RF 5301. The RF 5301 is the primary instrument used; the RF 5000U is primarily used as a back up instrument except for tracing studies which were beg un using t his instrument. Approximately 3 ml of the eluent is withdrawn from the sample container using a disposable polyethylene pipette, placed in a transparent, disposable rectangular polystyrene cuvette designed for fluorometric analysis, and then inse rted into the RF 5000U or the RF 5301. Positive detections will have peak emission wavelengths in the range from about 573 to 578 nm. A sample of the dye was shipped to OUL. To calculate detection limits OUL normally use s a sizeable collection of data However, this data set did not exist for P hloxine B. Howev er, the fluorescence peaks for P hloxine B are about 4 times larger per ppb of dye concen tration than are the peaks for P yranine. The detection limi t in elutants is 0.015 ppb for P yranine, so the e stimated detection limit for P hloxine B is about 25% of that or 0.004 ppb. (Tom Alley, personal communication, 8/20/12). Quality Control Field control samples were carried by staff collecting samples. Eight field control samples were analyzed by the EAA an d were non detect for Phloxine B. Split samples were taken from each site and sent for analyses to the EAA and OUL labs Laboratory quality control procedures i nclud ed dye standards, dupli cate and replicate samples, distilled water blanks, and rinsate sam ples described in Johnson et al. ( 2012 )

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BSEACD Report of Investigations 2013 0501 13 | Page RESULTS Lab results from the EAA and OUL are presented in Appendix 1 and 2 respectivel y. Results of the dye trace are summarized in Table 3 Breakthrough curves for three sites are shown in Figures 8 I nterprete d flow paths are presented in Figure 9 Table 3 : Sites monitored and r esults Site ID Site Name Type Ddlat Ddlong Linear Distance from Injection (miles) First Dye Arrival ( days ) Pumping Well Comment Positive 183A Upper Barton Spring 30.263563 97.774216 4.9 < 4 n/a OUL 2/2 2/7; both labs after 2/7 42914B Main Barton Spring 30.263683 97.770821 5.1 < 4 n/a Both labs 2/2 2/7 and after 5850207 Ashbaugh Domestic (Irrigation only) Well 30.217596 97.822845 1.0 < 7 yes OUL 2/6 2/10; both labs 2/10 2/16 Tentative 42921B Eliza Spring 30.264278 97.770172 5.1 < 8 T n/a possible EAA detection 2/9 2/11 5850230 Picard Domestic Well 30.226685 97.809219 1.9 < 7 T yes possible EAA detection 2/6 2/10 58501GR Randalls Monitor Well 30.2 23333 97.835281 0.4 < 3 T no possible EAA detection 2/3 2/6 58502 B 6200 Brodie Domestic Well 30.221865 97.826498 0.8 < 3 T yes possible EAA detection 2/3 2/6 Non D etects 42916C Cold Spring Spring 30.279593 97.780434 5.4 ND n/a 5850 2 SC Schaffer Abandoned well 30.221682 97.828135 0.7 ND no 42922B Old Mill Spring 30.26354 97.768066 5.2 ND n/a 5850235 Holiday Inn Monitor Well 30.234873 97.814096 1.8 ND no 5850212 Sunset MW Monitor Well 30.225475 97.806183 2.0 ND no 5850222 Besse Domestic Well 30.217216 97.818794 1.3 ND yes 58502JR Jenkins Domestic Well 30.217044 97.817631 1.4 ND yes 5850128 Whirlpool Monitor Well 30.215555 97.847221 0.5 ND no ND = Non detect; T = tentative

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BSEACD Report of Investigations 2013 0501 14 | Page

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BSEACD Report of Investigations 2013 0501 15 | Page Figure 8 Ph loxine B breakthrough graphs from the study. Both labs repeatedly detected Phloxine B at these three sites in charcoal samples. Additionally OUL detected dye in water samples from the three sites. A) Ashbaugh well, the only well monitoring site with both l abs returning positive results; B) Upper Barton Springs contained the highest concentrations of dye from both labs; and C) Main Barton Springs no sam ple.

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BSEACD Report of Investigations 2013 0501 16 | Page Figure 9. Map of results from the Arbor Trails Sinkhole dye trace. Pink circles indicate positive detections (very high confidence, both labs) of Phloxine B. White circles are wells with tentative detections (single detections from EAA lab) and solid black circles are locations with non detects (both labs). Dashed pink Hauwert et al., 2004. Small gray circles are existing water supply well s. Light gray potentiometric line s are from February 2002 high flow conditions.

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BSEACD Report of Investigations 2013 0501 17 | Page DISCUSSION Although n o background charcoal samples were in place prior to injection grab samples analyzed the day before and the day of, the injection were non detect. In addition, Phloxine B has never been utilized as a fluorescent dye in the Barton Springs segment of the Edwards Aquifer. Accordingly, background concentrations were not a major concern for this study. The first arrival of the Phloxine B dye was not well def ined by sampling at Barton Springs Charcoal receptors were placed at Upper and Main springs from 2/3 2/7, and both had a positive dye detection. Although we report a 4 day minimum travel time, O UL labs interpret ed the first arrival at Barton Springs with in 2 days ( Tom Alley, personal communication). Duplicate samples from the EAA and OUL were generally in agreement. Both labs repeatedly detected Phloxine B at the Ashbaugh well, Upper Barton Springs and Main Barton Springs. However, there were detection s reported by OUL that were not reported by the EAA. This is particularly true for water sample s The lower detection limit for the OUL lab (one order of magnitude lower) offers one explanation of the differences in results. However, the EAA lab indicated dye at four additional sites not reported by OUL but only from one sample at each site. Both labs re evaluated their respective samples and did not change their reported results ( Appendix 3 ). For the purposes of this study, those sites are listed as ten tative detections ( Table 3 ) CONCLUSIONS Results of this study were similar to other dye trace studies in this area by Hauwert et al., 2004. Rapid travel time (1.3 mi/day at a minimum) was documented from the ATS to Barton Springs Groundwater flow from t he William Cannon and Mo P ac area was within the Sunset Valley Groundwater Basin as delineated by Hauwert et al., 2004 Subtle karst features near fault zones, expressed as closed surface depressions can be very well integrated into the conduit flow system Phloxine B was a very good conservative tracer through the collapsed terra rosa material in the ATS. ACKNOWLEDGMENTS This study would not have been possible without the full support of the property owner of the Arbor Trails retail development Mr. Greg Christopher President of Christopher Commercial Inc. (CCI). We would also thank the CCI executive team of Vice President and General Counsel Dan Myrick, Construction and Maintenance Manager Dan Manchiela, and SWRP p roject manager Chuck Meehan. We would li ke to extend our thanks to the Edwards Aquifer Authority (EAA) and especially Geary Schindel for his support of the dye tracing portion of this study. The EAA provided Phloxine B dye and also performed the majority of the dye trace analyses.

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BSEACD Report of Investigations 2013 0501 18 | Page REFERENCES A Laboratory, Protem, Missouri 35 p. Aley, Thomas, 2008, Procedures and criteria, analysis of Uranine, Eosin, Rhodamine WT, Sulforhodamine B, and Pyranin e dyes in water and charcoal samplers, Ozark Underground Laboratory, Inc. December 15. Alexander, C.E., and J.F. Quinlan, 1992, Practical Tracing of Groundwater, With Emphasis on Karst Terranes, 2nd edition, Short Course Manual from the Annual Meeting of t he Geological Society of America, Cincinnati, Ohio, October 24, 1992, 38 p. Alexander, S.C. 2005, Spectral deconvolution and quantification of natural organic material and fluorescent tracer dyes. In: Sinkholes and the engineering and environmental impacts of karst: Proceedings of the 10th Multidisciplinary Conference, September 24 28, San Antonio: ASCE Geotechnical Special Publication No. 144, p. 441 448. Field, M.S., Wilhelm, R.G., Quinlan, J.F. and Aley, T.J., 1995, An assessment of the potential adverse properties of fluorescent tracer dyes used for groundwater tracing, Environmental Monitoring and Assessment volume 38, Kluwer Academic Publishers, pages 75 96. Hauwert, Nico, J.W. Sansom, D.A. Johns, and T.J. Aley, 2004, Groundwater Tracing Study of the B arton Springs Segment of the Edwards Aquifer, southern Travis and Northern Hays Counties, Texas, Barton Springs/Edwards Aquifer Conservation District and City of Austin Watershed Protection and Development Review Department, September, 110 p. and appendice s. HBC/Terracon, 2005, Geotechnical Engineering Study, The Shops at Arbor Trails Buidlings B & K, MoPac Expressway at William Cannon Drive, Austin, Texas, Report Prepared by Terracon Consultants, Inc., Geotechnical Engineering Division, Austin, Texas, Terr acon Project No. 96055226, November 23, 2005, 20 p. + Appendices HBC/Terracon, 2004, Geologic Assessment: The Shops at Arbor Trails, MoPac at William Cannon Drive, Austin, Tx, Report Prepared by HBC/Terracon, Austin, Texas, December 15, 2004, 9 p. Hunt, B. B. Smith, S. Hiers, N. Brown, 2013, Cover Collapse Sinkhole Development in the Cretaceous Edwards Limestone, Central Texas, Proceedings from the 13 th Annual Sinkhole Conference, Carlsbad, NM. Johnson, S., G. Schindel, G. Veni, N. Hauwert, B. Hunt, B. Smi th, and M. Gary, 2012, Tracing Groundwater Flowpaths in the Vicinity of San Marcos Springs, Texas, Edwards Aquifer Authority Report No. 12 03, San Antonio, August 2012, 139 p. Small, T.A., Hanson, J.A., and Hauwert, N.M., 1996, Geologic framework and hydr ogeologic characteristics of the Edwards Aquifer outcrop (Barton Springs segment), northeastern Hay sand southwestern Travis counties, Texas: U.S. Geological Survey, Water Resources Investigations Report 96 4306, 15 p., 1 sheet. Smart, P. L., 1984, A revie w of the toxicity of twelve fluorescent dyes used for water tracing, NSS Bulletin, Volume: 46, Issue: 2, Publisher: National Speleological Society, Huntsville, AL, Pages 21 33.

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BSEACD Report of Investigations 2013 0501 19 | Page Appendices Appendi x 1 : Dye Trace Results EAA Appendi x 2 : Dye Trace Results OUL Appendix 3 : Correspondence on confirmation of results

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BSEACD Report of Investigations 2013 0201 Appendices 1: Dye Trace Results EAA

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1 Arbor Trails Sinkhole Results Narrative Edwards Aquifer Authority (EAA) analyzed 201 samples submitted by Barton Springs Edwards Aquifer Conservation District (BSEACD) from the Arbor Trails Sinkhole project. Although vials from autosamplers and grab samples required no preparation before analysis, dye must be extracted from charcoal receptors prior to analysis by eluting the charcoal (desorbing the dye) for one hour in a solution containing 95% of a 70% solution of 2-propanol in water and 5% sodium hydroxide. The eluent was then decanted into a labeled glass vial and stored in darkness until analyzed. Uranine, Phloxine B, and Eosin in vials and eluents from charcoal were analyzed in the laboratory with a Perkin Elmer LS-50B Luminescence Spectrometer using synchronous scan and right-angle sampling geometry. The scan spanned 401 to 650 nm at 0.5-nm intervals, with a difference between excitation and emission wavelengths (delta lambda) of 15 nm and emission and excitation slits set at 6 nm. Dye Standards Results of the analysis are recorded in intensity units and converted to concentrations by comparison with known standards. Three standards were prepared for each of the three dyes detected in the tracer tests. Dye solutions were prepared on the basis of mass and diluted with deionized water filtered through a 0.2-micron filter to produce dye concentrations in the range that was expected in the water samples. To convert intensity to concentration, a power regression was calculated between intensity units and standard concentrations. For example, Figure 1 shows power regression of Uranine concentrations versus amplitude. Figure 1. Power Regression for Uranine

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2 Detection Limits Detection and quantitation limits for each dye were calculated from background fluorescence of naturally occurring fluorophores and instrument noise, following the method of Alexander (2005). The method defines limits of detection (LOD) and quantitation (LOQ) as three and 10 times the fit standard error of background fluorescence, respectively. Water samples were selected that contained dyes at concentrations just above background fluorescence to calculate LOD and LOQ, and fit standard error was calculated using peak-fitting software. For example, Figure 2 shows original intensities, separated dye peaks, and calculated LODs and LOQs for each dye. Using regression equations yields the limits of detection and quantitation for each dye in Table 1. Figure 2. Example of Peak Used for LOD Table 1. Limits of Detection and Quantitation for the Dyes Dye Sample Fit Standard Error Limit of Detection (g/L) Limit of Quantitation (g/L) Uranine (charcoal) Upper Barton 2/11/2012 1:05:00 PM 0. 54 0. 0061 0.020 Eosin (charcoal) 42916B 2/16/2012 2:14:00 PM 0.77 0.068 0.23 Phloxine B (charcoal) Upper Barton 2/11/2012 1:05:00 PM 0. 54 0. 0 44 0.1 5 Phloxine B (water) Upper Barton 2/19/2012 9:00:00 AM 0.54 0.0 44 0.1 5

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3 Control Samples One control sample (February 1, 2012; sample 100) of charcoal contained detectable concentrations of Uranine and Phloxine B because it was processed differently than the other charcoal samples. A contaminated pipettor was used to transfer eluent into a vial for analysis to avoid introducing suspended particles of charcoal into the vial. The normal procedure is to pour eluent from the desorption cup into a vial. When the analyst observed dye in the results, he prepared a new sample from the remaining charcoal and poured eluent into a vial for analysis. The second sample contained no detectable dyes. Consequently, none of the sample results were compromised. References Alexander, S.C. 2005, Spectral deconvolution and quantification of natural organic material and fluorescent tracer dyes In: Sinkholes and the engineering and environmental impacts of karst: Proceedings of the 10th Multidisciplinary Conference, September 2428, San Antonio: ASCE Geotechnical Special Publication No. 144, p. 441448.

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4 Results for Arbor Trails Sinkhole Sample No Sample Site Name Sample Name Set Date Collected Center Height FWHM Peak Area Dye Conc entration (g/L) 154 Water 6200 Brodie 58 50 2 2/3/2012 2:10 PM ND 160 Water 6200 Brodie 58 50 2 2/6/2012 1:02 PM ND 194 Charcoal 6200 Brodie 58 50 2 2/3/2012 2:10 PM 2/6/2012 1:02 PM 493.2 9.1 31.4 310 Uranine 0.76 194 Charcoal 6200 Brodie 58 50 2 2/3/2012 2:10 PM 2/6/2012 1:02 PM 555.1 0.88 27.9 38.7 Phloxine B 1.4 204 Water 6200 Brodie 58 50 2 2/7/2012 ND 164 Water 6200 Brodie 58 50 2 2/10/2012 2:55 PM ND 114 Charcoal 6200 Brodie 58 50 2 2/10/2012 2:55 PM 2/10/2012 2:55 PM ND 124 Charcoal 6200 Brodie 58 50 2 2/16/2012 11:55 AM 2/16/2012 11:55 AM ND 170 Water 6200 Brodie 58 50 2 2/16/2012 11:55 AM ND 123 Charcoal 6200 Brodie 58 50 2 2/10/2012 2:45 PM 2/16/2012 12:05 PM ND 198 Charcoal 6200 Brodie 58 50 2 2/16/2012 11:55 AM 2/23/2012 1:45 PM ND 214 Charcoal 6200 Brodie 58 50 2 2/23/2012 1:45 PM 3/5/2012 1:30 PM ND 203 Water Ashbaugh 58 50 207 2/23/2012 1:35 PM ND 213 Water Ashbaugh 58 50 207 3/5/2012 1:10 PM ND 155 Water Ashbaugh 58 50 207 2/3/2012 2:17 PM ND 107 Charcoal Ashbaugh 58 50 207 2/6/2012 12:53 PM 2/6/2012 12:53 PM ND 159 Water Ashbaugh 58 50 207 2/6/2012 12:53 PM ND 163 Water Ashbaugh 58 50 207 2/10/2012 2:30 PM ND 113 Charcoal Ashbaugh 58 50 207 2/10/2012 2:30 PM 2/10/2012 2:30 PM 546.2 4.9 21.7 126 Phloxine B 4.8 169 Water Ashbaugh 58 50 207 2/16/2012 11:35 AM ND 122 Charcoal Ashbaugh 58 50 207 2/16/2012 11:35 AM 2/16/2012 11:35 AM 546.5 6.3 21.5 191 Phloxine B 7.5 122 Charcoal Ashbaugh 58 50 207 2/16/2012 11:35 AM 2/16/2012 11:35 AM 496.4 5.6 45.0 268 Uranine 0.67 197 Charcoal Ashbaugh 58 50 207 2/16/2012 11:35 AM 2/23/2012 1:35 PM ND 212 Charcoal Ashbaugh 58 50 207 2/23/2012 1:35 PM 3/5/2012 1:10 PM 546.5 5.4 22.8 174 Phloxine B 6.8 212 Charcoal Ashbaugh 58 50 207 2/23/2012 1:35 PM 3/5/2012 1:10 PM 546.7 5.7 20.9 177 Phloxine B 6.9 152 Water Besse 58 50 222 2/3/2012 1:09 PM ND 158 Water Besse 58 50 222 2/6/2012 12:44 PM ND 202 Water Besse 58 50 222 2/10/2012 ND 211 Water Besse 58 50 222 2/10/2012 ND 162 Water Besse 58 50 222 2/10/2012 2:25 PM ND 112 Charcoal Besse 58 50 222 2/10/2012 2:25 PM 2/10/2012 2:25 PM ND 168 Water Besse 58 50 222 2/16/2012 11:30 AM ND 121 Charcoal Besse 58 50 222 2/16/2012 11:30 AM 2/16/2012 11:30 AM ND 196 Charcoal Besse 58 50 222 2/16/2012 11:30 AM 2/23/2012 12:55 PM ND 210 Charcoal Besse 58 50 222 2/23/2012 12:55 PM 3/5/2012 1 PM ND 286 Water Cold Spring 42916 2/3/2012 5:30 PM ND 192 Water Cold Spring 42916 2/10/2012 3:45 PM ND

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5 Sample No Sample Site Name Sample Name Set Date Collected Center Height FWHM Peak Area Dye Conc entration (g/L) 142 Charcoal Cold Spring 42916C 2/3/2012 5:35 PM 2/10/2012 3:50 PM 523.7 185 20.1 4085 Eosin 46.1 193 Water Cold Spring 42916 2/16/2012 2:12 PM ND 129 Charcoal Cold Spring 42916B 2/10/2012 3:47 PM 2/16/2012 2:14 PM 523.8 206 19.9 4512 Eosin 50.2 281 Charcoal Cold Spring 42916 2/16/2012 2:12 PM 3/13/2012 1:25 PM ND 276 Water Cold Spring 42916 3/13/2012 1:35 PM ND 219 Charcoal Control Control 3/5/2012 3/5/2012 ND 100 Charcoal Control Control 2/1/2012 5 PM 2/1/2012 5 PM ND 100 Charcoal Control Control 2/1/2012 5 PM 2/1/2012 5 PM 549.1 0.98 23.7 33.5 Phloxine B 1.2 100 Charcoal Control Control 2/1/2012 5 PM 2/1/2012 5 PM 492.1 9.6 30.7 324 Uranine 0.79 102 Charcoal Control Control 2/3/2012 2/3/2012 ND 101 Charcoal Control Control 2/3/2012 2/3/2012 ND 110 Charcoal Control Control 2/6/2012 2/6/2012 ND 120 Charcoal Control Control 2/10/2012 2/10/2012 ND 127 Charcoal Control Control 2/16/2012 2/16/2012 ND 128 Charcoal Control Control 2/16/2012 2/16/2012 ND 287 Water Eliza 42921 2/2/2012 1:45 PM ND 139 Charcoal Eliza 42921A 2/2/2012 1:45 PM 2/7/2012 4:45 PM ND 185 Water Eliza 42921 2/7/2012 4:50 PM ND 144 Charcoal Eliza 42921A 2/7/2012 4:45 PM 2/9/2012 2:15 PM ND 190 Water Eliza 42921 2/9/2012 2:20 PM ND 173 Water Eliza 42921 2/10/2012 4:40 PM ND 148 Charcoal Eliza 42921B 2/9/2012 2:17 PM 2/10/2012 4:42 PM ND 131 Charcoal Eliza 42921A 2/10/2012 4:40 PM 2/11/2012 9:45 AM ND 176 Water Eliza 42921 2/11/2012 9:45 AM ND 149 Charcoal Eliza 42921C 2/9/2012 2:20 PM 2/11/2012 9:50 AM 548.1 5.0 18.9 101 Phloxine B 3.9 181 Water Eliza 42921 2/16/2012 3:15 PM ND 134 Charcoal Eliza 42921A 2/11/2012 9:45 AM 2/16/2012 3:15 PM ND 270 Water Eliza 42921 2/28/2012 3:20 PM ND 275 Charcoal Eliza 42921 2/16/2012 3:17 PM 2/28/2012 3:22 PM ND 278 Water Eliza 42921 3/13/2012 2:10 PM ND 283 Charcoal Eliza 42921 2/28/2012 3:20 PM 3/13/2012 2:10 PM ND 106 Charcoal Holiday Inn 58 50 235 2/3/2012 1:57 PM 2/6/2012 1:57 PM ND 117 Charcoal Holiday Inn 58 50 235 2/6/2012 1:57 PM 2/16/2012 12:50 PM ND 153 Water Jenkins 58 50 2JR 2/3/2012 1:15 PM ND 104 Charcoal Jenkins 58 50 2JR 2/6/2012 12:37 PM 2/6/2012 12:37 PM ND 104 Charcoal Jenkins 58 50 2JR 2/6/2012 12:37 PM 2/6/2012 12:37 PM ND 157 Water Jenkins 58 50 2JR 2/6/2012 12:37 PM ND 201 Water Jenkins 58 50 2JR 2/7/2012 ND 207 Water Jenkins 58 50 2JR 2/10/2012 ND

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6 Sample No Sample Site Name Sample Name Set Date Collected Center Height FWHM Peak Area Dye Conc entration (g/L) 166 Water Jenkins 58 50 2JR 2/10/2012 2:10 PM ND 111 Charcoal Jenkins 58 50 2JR 2/6/2012 12:37 PM 2/12/2012 2:10 PM ND 126 Charcoal Jenkins 58 50 2JR 2/16/2012 11:20 AM 2/16/2012 11:20 AM ND 167 Water Jenkins 58 50 2JR 2/16/2012 11:20 AM ND 195 Charcoal Jenkins 58 50 2JR 2/16/2012 11:20 AM 2/23/2012 12:35 PM ND 206 Charcoal Jenkins 58 50 2JR 2/23/2012 12:35 PM 3/5/2012 12:50 PM ND 145 Charcoal Main Barton 42914A 2/7/2012 5 PM 2/9/2010 2:35 PM ND 188 Water Main Barton 42914 2/9/2010 2:35 PM ND 288 Water Main Barton 42914 2/2/2012 2 PM ND 140 Charcoal Main Barton 42914A 2/2/2012 2 PM 2/7/2012 5 PM 547.3 9.9 22.1 191 Phloxine B 7.5 186 Water Main Barton 42914 2/7/2012 5 PM ND 174 Water Main Barton 42914 2/10/2012 4:55 PM ND 150 Charcoal Main Barton 42914B 2/9/2012 2:37 PM 2/10/2012 4:57 PM 547.7 11.9 18.9 260 Phloxine B 10.3 179 Water Main Barton 42914 2/11/2012 2:05 PM ND 132 Charcoal Main Barton 42914A 2/10/2012 4:55 PM 2/11/2012 2:05 PM 548.1 14.8 19.4 308 Phloxine B 12.2 182 Water Main Barton 42914 2/16/2012 3:30 PM ND 137 Charcoal Main Barton 42914A 2/11/2012 2:05 PM 2/16/2012 3:30 PM ND 269 Water Main Barton 42914 2/28/2012 3:35 PM ND 273 Charcoal Main Barton 42914 2/16/2012 3:32 PM 2/28/2012 3:37 PM 547.7 39.3 19.4 858 Phloxine B 35.3 277 Water Main Barton 42914 3/13/2012 2:30 PM ND 285 Charcoal Main Barton 42914 2/28/2012 3:35 PM 3/13/2012 2:30 PM ND 290 Water Old Mill 42922 2/2/2012 2:30 PM ND 141 Charcoal Old Mill 42922B 2/2/2012 2:32 PM 2/7/2012 5:27 PM ND 187 Water Old Mill 42922 2/7/2012 5:30 PM ND 146 Charcoal Old Mill 42922A 2/7/2012 5:25 PM 2/9/2012 3 PM ND 191 Water Old Mill 42922 2/9/2012 3 PM ND 151 Charcoal Old Mill 42922A 2/9/2012 3 PM 2/10/2012 5:15 PM ND 175 Water Old Mill 42922 2/10/2012 5:15 PM ND 133 Charcoal Old Mill 42922A 2/10/2012 5:15 PM 2/11/2012 1:30 PM ND 178 Water Old Mill 42922 2/11/2012 1:30 PM ND 183 Water Old Mill 42922 2/16/2012 3:50 PM ND 136 Charcoal Old Mill 42922B 2/11/2012 1:32 PM 2/16/2012 3:52 PM ND 271 Water Old Mill 42922 2/28/2012 4 PM ND 272 Charcoal Old Mill 42922 2/16/2012 3:52 PM 2/28/2012 4:02 PM ND 272 Charcoal Old Mill 42922 2/16/2012 3:52 PM 2/28/2012 4:02 PM ND 280 Water Old Mill 42922 3/13/2012 3:15 PM ND 284 Charcoal Old Mill 42922 2/28/2012 4 PM 3/13/2012 3:15 PM ND 218 Water Picard 58 50 230 3/5/2012 2:10 PM ND 156 Water Picard 58 50 230 2/3/2012 4:34 PM ND

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7 Sample No Sample Site Name Sample Name Set Date Collected Center Height FWHM Peak Area Dye Conc entration (g/L) 161 Water Picard 58 50 230 2/6/2012 1:16 PM ND 161 Water Picard 58 50 230 2/6/2012 1:16 PM ND 109 Charcoal Picard 58 50 230 2/6/2012 1:16 PM 2/6/2012 1:16 PM 554.1 0.79 47.2 40.9 Phloxine B 1.5 205 Water Picard 58 50 230 2/9/2012 ND 165 Water Picard 58 50 230 2/10/2012 3:05 PM ND 165 Water Picard 58 50 230 2/10/2012 3:05 PM ND 115 Charcoal Picard 58 50 230 2/10/2012 3:05 PM 2/10/2012 3:05 PM ND 125 Charcoal Picard 58 50 230 2/16/2012 12:20 PM 2/16/2012 12:20 PM ND 171 Water Picard 58 50 230 2/16/2012 12:20 PM ND 200 Charcoal Picard 58 50 230 2/16/2012 12:20 PM 2/23/2012 2:20 PM ND 217 Charcoal Picard 58 50 230 2/23/2012 2:20 PM 3/5/2012 2:10 PM ND 103 Charcoal Randalls 58 50 1GR 2/3/2012 10:50 AM 2/6/2012 2:14 PM 553.7 1.6 33.0 94.0 Phloxine B 3.6 103 Charcoal Randalls 58 50 1GR 2/3/2012 10:50 AM 2/6/2012 2:14 PM 493.2 13.8 34.8 542 Uranine 1.3 118 Charcoal Randalls 58 50 1GR 2/6/2012 2:14 PM 2/16/2012 1:05 PM ND 208 Charcoal Randalls 58 50 1GR 2/16/2012 1:05 PM 3/5/2012 11:45 AM ND 215 Water Schaffer 58 50 2 2/9/2012 ND 199 Charcoal Schaffer 58 50 2 2/16/2012 12:05 PM 2/23/2012 2 PM ND 216 Charcoal Schaffer 58 50 2 2/23/2012 2 PM 3/5/2012 1:40 PM ND 105 Charcoal Sunset MW 58 50 212 2/3/2012 1:40 PM 2/6/2012 1:34 PM ND 116 Charcoal Sunset MW 58 50 212 2/6/2012 1:34 PM 2/16/2012 12:35 PM ND 289 Water Upper Barton 183 2/2/2012 1:30 PM ND 220 Water Upper Barton 183 2/7/2012 9 AM ND 138 Charcoal Upper Barton 183A 2/2/2012 1:20 PM 2/7/2012 4:20 PM ND 184 Water Upper Barton 183 2/7/2012 4:20 PM ND 221 Water Upper Barton 183 2/7/2012 5 PM ND 222 Water Upper Barton 183 2/8/2012 1 AM ND 223 Water Upper Barton 183 2/8/2012 5 PM ND 224 Water Upper Barton 183 2/9/2012 1 AM ND 225 Water Upper Barton 183 2/9/2012 9 AM ND 143 Charcoal Upper Barton 183A 2/7/2012 4:20 PM 2/9/2012 2 PM 547.5 57.4 19.5 1246 Phloxine B 51.9 189 Water Upper Barton 183 2/9/2012 2 PM ND 226 Water Upper Barton 183 2/9/2012 5 PM ND 227 Water Upper Barton 183 2/10/2012 1 AM ND 228 Water Upper Barton 183 2/10/2012 9 AM ND 147 Charcoal Upper Barton 183A 2/9/2012 2 PM 2/10/2012 4:25 PM 545.0 4.6 18.9 104 Phloxine B 4.0 147 Charcoal Upper Barton 183A 2/9/2012 2 PM 2/10/2012 4:25 PM 545.9 5.6 19.6 119 Phloxine B 4.6 172 Water Upper Barton 183 2/10/2012 4:25 PM ND 229 Water Upper Barton 183 2/10/2012 5 PM ND 229 Water Upper Barton 183 2/10/2012 5 PM ND

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8 Sample No Sample Site Name Sample Name Set Date Collected Center Height FWHM Peak Area Dye Conc entration (g/L) 230 Water Upper Barton 183 2/11/2012 1 AM ND 231 Water Upper Barton 183 2/11/2012 9 AM ND 130 Charcoal Upper Barton 183A 2/10/2012 4:25 PM 2/11/2012 1:05 PM 547.3 4.7 17.7 46.8 Phloxine B 1.8 177 Water Upper Barton 183 2/11/2012 1:05 PM ND 130 Charcoal Upper Barton 183A 2/10/2012 4:25 PM 2/11/2012 1:05 PM 546.5 5.5 20.6 145 Phloxine B 5.6 130 Charcoal Upper Barton 183A 2/10/2012 4:25 PM 2/11/2012 1:05 PM 495.8 6.6 45.6 386 Uranine 0.93 232 Water Upper Barton 183 2/11/2012 5 PM ND 233 Water Upper Barton 183 2/12/2012 1 AM ND 234 Water Upper Barton 183 2/12/2012 9 AM ND 235 Water Upper Barton 183 2/12/2012 5 PM ND 236 Water Upper Barton 183 2/13/2012 1 AM ND 237 Water Upper Barton 183 2/13/2012 9 AM ND 238 Water Upper Barton 183 2/13/2012 5 PM ND 239 Water Upper Barton 183 2/14/2012 1 AM ND 240 Water Upper Barton 183 2/14/2012 9 AM ND 241 Water Upper Barton 183 2/14/2012 5 PM ND 242 Water Upper Barton 183 2/15/2012 1 AM ND 243 Water Upper Barton 183 2/15/2012 9 AM ND 180 Water Upper Barton 183 2/16/2012 2:55 PM ND 135 Charcoal Upper Barton 183A 2/11/2012 1:05 PM 2/16/2012 2:55 PM 547.5 65.6 19.6 1444 Phloxine B 60.4 244 Water Upper Barton 183 2/17/2012 5 PM ND 245 Water Upper Barton 183 2/18/2012 1 AM ND 246 Water Upper Barton 183 2/18/2012 9 AM ND 247 Water Upper Barton 183 2/18/2012 5 PM 533.0 1.8 32.5 92.3 Phloxine B 3.5 247 Water Upper Barton 183 2/18/2012 5 PM 533.7 1.6 32.8 74.7 Phloxine B 2.8 248 Water Upper Barton 183 2/19/2012 1 AM 536.3 5.2 20.4 125 Phloxine B 4.8 249 Water Upper Barton 183 2/19/2012 9 AM 535.8 2.5 20.9 85.3 Phloxine B 3.3 250 Water Upper Barton 183 2/19/2012 5 PM 535.2 2.1 21.8 59.7 Phloxine B 2.3 251 Water Upper Barton 183 2/20/2012 1 AM 535.0 2.5 25.4 96.0 Phloxine B 3.7 252 Water Upper Barton 183 2/20/2012 9 AM 535.3 2.2 1 95.4 Phloxine B 3.7 253 Water Upper Barton 183 2/20/2012 5 PM 535.8 2.8 26.4 204 Phloxine B 8.0 254 Water Upper Barton 183 2/21/2012 1 AM 535.5 2.9 21.0 90.8 Phloxine B 3.5 255 Water Upper Barton 183 2/21/2012 9 AM 532.8 2.3 32.3 94.7 Phloxine B 3.6 256 Water Upper Barton 183 2/21/2012 5 PM 534.5 2.0 1 87.4 Phloxine B 3.3 257 Water Upper Barton 183 2/22/2012 1 AM 535.9 2.7 21.6 80.6 Phloxine B 3.1 258 Water Upper Barton 183 2/22/2012 9 AM ND 259 Water Upper Barton 183 2/22/2012 5 PM 536.1 2.3 24.0 92.9 Phloxine B 3.6 260 Water Upper Barton 183 2/23/2012 1 AM 538.5 1.8 17.4 36.4 Phloxine B 1.4 261 Water Upper Barton 183 2/23/2012 9 AM 534.8 2.1 26.2 82.8 Phloxine B 3.2

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9 Sample No Sample Site Name Sample Name Set Date Collected Center Height FWHM Peak Area Dye Conc entration (g/L) 262 Water Upper Barton 183 2/23/2012 5 PM 535.0 2.5 33.0 222 Phloxine B 8.7 263 Water Upper Barton 183 2/24/2012 1 AM ND 264 Water Upper Barton 183 2/24/2012 9 AM 536.6 1.7 23.3 4.3 Phloxine B 0.15 J 265 Water Upper Barton 183 2/24/2012 5 PM 533.4 1.6 32.1 1.3 Phloxine B 0.043 J 266 Water Upper Barton 183 2/25/2012 1 AM 535.1 1.9 24.8 88.6 Phloxine B 3.4 267 Water Upper Barton 183 2/25/2012 9 AM 534.8 2.0 27.1 85.1 Phloxine B 3.2 268 Water Upper Barton 183 2/28/2012 2:45 PM ND 274 Charcoal Upper Barton 183 2/16/2012 2:17 PM 2/28/2012 2:50 PM 548.5 1708 20.0 42 000 Phloxine B 1962 279 Water Upper Barton 183 3/13/2012 2:55 PM ND 282 Charcoal Upper Barton 183 2/28/2012 2:45 PM 3/13/2012 2:55 PM 546.4 11.3 18.1 201 Phloxine B 7.9 282 Water Upper Barton 183 3/13/2012 2:55 PM 546.5 11.3 17.6 313 Phloxine B 12.5 119 Charcoal Whirlpool 58 50 128 2/6/2012 2:45 PM 2/16/2012 1:20 PM ND 209 Charcoal Whirlpool 58 50 128 2/16/2012 1:20 PM 3/5/2012 12:20 PM ND ND indicates not detected at the following limits of detection: Uranine (charcoal) 0.0061 g/L Eosin (charcoal) 0.068 g/L Phloxine B (charcoal) 0.044 g/L Phloxine B (water) 0.044 g/L J indicates detection between limit of detection and limit of quantitation. FWHM indicates full width at half maximum.

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BSEACD Report of Investigations 2013 0201 Appendices 2: Dye Trace Results OUL

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BSEACD Report of Investigations 2013 0201 Appendix 3: Correspondence on confirmation of results

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1 Brian Hunt From: Julie Stearman [jstearman@ozarkundergroundlab.com] on behalf of taley@ozarkundergroundlab.com Sent: Tuesday, May 15, 2012 9:52 AM To: Brian Hunt Subject: RE: Confirmation of ResultsHi Brian: At your request I re examined the analysis graphs for the following three samples. I also had our lab do a re analyzed of the three samples. The re analysis showed the following: V5656P. This is Station 6. 58502 6200 Brodie. This was a charcoal sampler elutant. Ther e is a fluorescence peak in this sample at 521.2 nm. The results confirmed the initial analysis. V5687P. This is Station 11. 5850230 Picard. This was a charcoal sampler elutant. There were no fluorescence peaks in this sample. The results confirmed the initial analysis. V5689P. This is Station 12. 58501GR Randalls. This was a charco al sampler elutant. There was a fluorescence peak in this sample at 519.3 nm. The results confirmed the initial analysis. Under the protocol we are using for phloxine dye positive detections will have peak emission wavelengths in the range from about 573 to 578 nm. The fluorescence peaks at Stations 6 and 12 were far outside of this range. The peaks were also well outside the range for pyranine dye. Based upon both our initial and our re analysis results there was no detectable phloxine dye or pyranine dye in any of these three samples. Best regards, Tom Aley From: Brian Hunt [mailto:brianh@bseacd.org] Sent: Thursday, May 10, 2012 5:46 PM To: Julie Stearman Cc: Brian Hunt Subject: RE: Invoice Hi Julie, For our recent study we had some duplicate charcoal and water samples analyzed by the Edwards Aquifer Authority. For the most part there is good agreement in the all results, but there are three samples that I wonder if you could look at your analyses to reconfirm the results. These include three different wells where your results indicate a non detect, while the EAA indicates a detection of Phloxine B. They only detected the dye once in each of these wells corresponding to the samples I listed below. The samples are: V5656P, V5687P, and V5689P. Thank you!

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2Cheers, Brian Brian B. Hunt Senior Hydrogeologist Barton Springs/Edwards Aquifer Conservation District 1124 Regal Row Austin, Texas 78748 (512) 282-8441 office (512) 282-7016 fax brianh@bseacd.org Here's all the legal stuff: This message is intended only for the named recipient. If you are not the intended recipient, you are notified that disclosing copying, distributing or taking any action in reliance on the contents of this information is strictly pr ohibited, and you are hereby instructed to notify the Sender by reply email and then immediately delete this email message. From: Julie Stearman [mailto:jstearman@ozarkundergroundlab.com] Sent: Tuesday, March 20, 2012 10:56 AM To: Brian Hunt Subject: Invoice Hello Brian, Please see the attached invoice; let me know if you have any questions. Thank you, Julie Stearman

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1 Brian Hunt From: Steven Johnson [sjohnson@edwardsaquifer.org] Sent: Friday, May 11, 2012 3:37 PM To: Brian Hunt Subject: RE: dye trace resultsBrian, the yellow line is the combination of the two peaks in the sample that are shown in red. The green line is the original spectrograph. The peaks around 500 are Uranine as in 194 and 103 or background optical properties of water as in 109 and 115. Steve Johnson Hydrogeologist Supervisor Aquifer Science Team Edwards Aquifer Authority 1615 N. St. Mary's StreetSan Antonio, TX 78215210/222 2204 mailto:sjohnson@edwardsaquifer.org From: Brian Hunt [mailto:brianh@bseacd.org] Sent: Friday, May 11, 2012 3:04 PM To: Steven Johnson Subject: RE: dye trace results Steve, the yellow line is the sample and the two red lines are for the standard and blank? Thanks again! b Brian B. Hunt Senior Hydrogeologist Barton Springs/Edwards Aquifer Conservation District 1124 Regal Row Austin, Texas 78748 (512) 282-8441 office (512) 282-7016 fax brianh@bseacd.org Here's all the legal stuff: This message is intended only for the named recipient. If you are not the intended recipient, you are notified that disclosing copying, distributing or taking any action in reliance on the contents of this information is strictly pr ohibited, and you are hereby instructed to notify the Sender by reply email and then immediately delete this email message. From: Steven Johnson [ mailto:sjohnson@edwardsaquifer.org ] Sent: Friday, May 11, 2012 10:08 AM To: Brian Hunt Subject: RE: dye trace results Brian, here are the three sample results:

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2 sample #194 (6200 Brodie, charcoal 2/32/6) Phloxine B shows up around 550 nm. In this case, its a very low concentration, but I think its there. #103 (Randalls, charcoal 2/32/6) Same results as above #109 (Picard, charcoal 2/6 2/10) This one has the lowest concentration. Phloxine B is more easily recognized than Uranine and Eosin because it appears where the background interference is low. I have the dates as 2/32/6/10.

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3 For comparison, heres sample #115 from Picard with no detectable Phloxine B so you can see the contrast in the 550 nm area. I would call the other samples tentative detections at least because they were in only one sample from the site and because the peak shape is somewhat subjective. St eve Johnson Hydrogeologist Supervisor Aquifer Science Team Edwards Aquifer Authority 1615 N. St. Mary's StreetSan Antonio, TX 78215210/222 2204 mailto:sjohnson@edwardsaquifer.org From: Brian Hunt [mailto:brianh@bseacd.org ] Sent: Thursday, May 10, 2012 5:59 PM To: Steven Johnson Cc: Brian Smith Subject: dye trace results Hi Steve, We some of the dye trace samples to OUL labs as duplicates. For the most part there is good agreement in the results where they overlap. However, there are 3 sites that you all detect Phloxine B and OUL did not. I wanted to see if perhaps you wouldnt min d looking at the results of those 3 sites againif possible. The three samples include: EAA sample #194 (6200 Brodie, charcoal 2/32/6); #103 (Randalls, charcoal 2/32/6); and #109 (Picard, charcoal 2/6 2/10). I suspect those sites would have been on the flow path, and since they were only detected on ce, and by only 1 lab, I am trying to confirm or deny. Ive asked OUL to review those three samples too. Thanks! Cheers, Brian


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