Citation
Hydrological and geochemical characteristics in the Edwards and Trinity hydrostratigraphic units using multiport monitor wells in the Balcones Fault Zone, Hays county, central Texas.

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Title:
Hydrological and geochemical characteristics in the Edwards and Trinity hydrostratigraphic units using multiport monitor wells in the Balcones Fault Zone, Hays county, central Texas.
Creator:
Barton Springs/Edwards Aquifer Conservation District
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Language:
English

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Subjects / Keywords:
Barton Springs (Austin, Texas, United States) ( 30.263819, -97.771395 )
Geology ( local )
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serial ( sobekcm )
Location:
United States
Coordinates:
30.263819 x -97.771395

Notes

General Note:
Introduction * Permeabilities are a defining characteristic of aquifers. * Detailed permeability data for distinct litho/hydrostratigraphic units in the Edwards and Trinity Aquifers has not been quantified in a single borehole. * Hydrologic connection between hydrostratigraphic units in this area is not entirely understood and needs more thorough characterization to better manage water resources. * Two Westbay multiport wells were used to measure hydrogeologic characteristics of rock units.
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Open Access - Permission by Publisher
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See Extended description for more information.

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University of South Florida Library
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University of South Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
K26-01543 ( USFLDC DOI )
k26.1543 ( USFLDC Handle )
11748 ( karstportal - original NodeID )

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Karst Information Portal

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Full Text
Description
Introduction Permeabilities are a defining
characteristic of aquifers. Detailed permeability data for
distinct litho/hydrostratigraphic units in the Edwards and
Trinity Aquifers has not been quantified in a single
borehole. Hydrologic connection between hydrostratigraphic
units in this area is not entirely understood and needs more
thorough characterization to better manage water resources.
Two Westbay multiport wells were used to measure
hydrogeologic characteristics of rock units.



PAGE 1

Hydrostratigraphy Hammett Shale Cow Creek Hensel Lower Member Glen Rose Limestone Upper Member Glen Rose Limestone Georgetown Fm. BudaEagle Ford/Qal?Leached and Collapsed mbrsDolomitic mbr Kirschberg mbrGrainstone mbr Reg. Dense mbrBasal Nodular mbrKainer Fm. Person Fm.Depth (ft)Edwards GroupTD = 1,375 ftpacker 1.5 in dia PVC coupling sampleport 21 20 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 19 Del Rio CA Gamma (cps) 100 0 40 80 120 160 200 240 280 320 360 400 440 480 520 560 600 640 680 720 760 800 840 880 920 960 1000 1040 1080 1120 1160 1200 1240 1280 1320 1360 133.5 Oyster wake-packstone 165.4 Caprinid rudistupper reef lower reef291.2 toucasid wake-packstone 599.1 clasts? b f,m f f f b f f f f f f f f f f f b b b m m b b b f f fLith. Notes5 10 Caliper (in) 154.2 fracture 199.6 fossil (toucasid) vug 238 solutioned fracture 283 solutioned fracture 230 solutioned bedding plane b vuggy zone Select Borehole Photographs A) Solutioned fracture zone 20, Person Fm, Edwards Grp. B) Moddled texture zone 18, Person Fm, Edwards Grp. A B C D ED) Anhydrite/gypsum nodules zone 7, Lower Glen Rose Mbr. E) Solutioned fracture zone 1, Cow Creek Fm. C) Cavernous zone 17, Kainer Fm, Edwards Grp. irregular bedding laminar bedding shale beds chickenwire texture rudistid shell fossil fracture breccia chert nodule gypsum pyrite calcite spar f = fracture m = moldic b = beddingSymbols Porosity A USTINKYLE Hwy 290 Bar ton Spr ingsCold Spr ings 0 2 miles IH-35IH-35Fm 1826B UD ATravis County Hays CountyN Onion CreekLittle Bear CreekBarton CreekWilliamson CreekBlanco RiverBearCreek D DRecharge Zone Saline (brackish) ZoneConfined ZoneContributing Zone Antioch Well Ruby Well 100 200 300 400 500 600 700 800 900 1000 1100 Depth (feet) Stratigraphy TD = 1,120 ft 13 14 12 1 1 10 9 8 7 6 5 4 3 2 1Multiport W ell Elevation (ft-msl) vs Depth (ft) Ruby Ranch Westbay Well 329 ns 263 66 1.6 28 0.1 0.01 1.2 32 0.6 0.2 70 42 64 1,320 (4/08)to 289(6/09)3,270 3,852 3,291 675 857 674 852 644 771 509 TDS K (mg/L) (ft/d) Hammett Shale Cow Creek Hensel Lower Member Glen Rose Limestone Dolomitic Member Walnut Fm. Upper Member Glen Rose Limestone Edwards GroupKainer Formation815 ft-msl Middle Trinity Aquifer Upper Trinity Aquifer Edwards Aquifer 6 3 5 3 0 6 5 0 5 1 6 4 4 4 2 6 5 5 8 0 620 640 660 680 700 720 Rudist Reef 9/30/10 12/2/10 2/18/11 5/18/11 Hydrostratigraphy Hammett Shale Cow Creek Hensel Lower Mbr Glen Rose Limestone Upper Mbr Glen Rose Limestone Georgetown BudaLeached & Collapsed mbrs Dolomitic mbr Kirschberg mbr Grainst RDMWalnut FmKainer Fm. Person Depth (ft) Edwards Group 21 20 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 19 Del Rio 702 ft-msl 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 Elevation (ft-msl) vs Depth (ft) Antioch Westbay Well ns ns 288 304 302 446 439 3,567 2,884 3,037 2,853 2,993 3,268 2,141 2,658 553 711 963 927 273 279 K (ft/d) TDS (mg/L) 570 590 610 630 9/30/10 12/2/10 2/16/11 5/18/11 TD = 1,375 ft0.3 3.3 38 29 29 8.3 4 0.1 0.1 0.2 0.5 0.4 0.3 0.1 0.2 5.8 0.2 1.1 19 53 4.5 Hydrological and Geochemical Characteristics in the Edwards and Trinity Hydrostratigraphic Units Using Multiport Monitor Wells in the Balcones Fault Zone, Hays County, Central Texas Alan Andrews, Brian Hunt, Brian Smith Purpose To better understand the hydrogeological properties of and relationships between the geologic units that make up the Edwards, Upper and Middle Trinity Aquifers and to compare observed hydrologic properties of formations to generally accepted understanding of them and suggest nomenclature that best describes hydrogeologic properties of hydrostratigraphic units in the study area. Introduction Permeabilities are a dening characteristic of aquifers. Detailed permeability data for distinct litho/hydrostratigraphic units in the Edwards and Trinity Aquifers has not been quantied in a single borehole. Hydrologic connection between hydrostratigraphic units in this area is not entirely understood and needs more thorough characterization to better manage water resources. Two Westbay multiport wells were used to measure hydrogeologic characteristics of rock units. Location Methods Two Westbay multiport wells were used to measure water levels, conduct rising/falling head and slug tests, and collect water samples at ports located at dierent depths, and screened individually to distinct litho/hydrostratigraphic layers. Conclusions Observed hydraulic conductivities of the various formations that make up the Edwards Aquifer (Fig. 3) generally agree with those qualitatively assigned by previous studies. Upper-most units of the Upper Glen Rose exhibit high hydraulic conductivity and good quality water similar to units in the Edwards Aquifer. Most of the Upper Trinity Aquifer is best described as an aquitard and conning unit in this area, especially when comparing its hydraulic conductivities to those found in the Edwards and Middle Trinity Aquifers. Uppermost units of the Lower Member of the Glen Rose Limestone exhibit low hydraulic conductivity (<1 ft/d) and high TDS (2100 to 3200 mg/l), resembling values found in the Upper Trinity Aquitard. Dierences in head, hydraulic conductivity, and geochemistry between hydrostratigraphic layers indicate that minimal vertical ow occurs between them. Tables 1 and 2. List distribution of hydraulic conductivities in Ruby Ranch (left) and Antioch (right) multiport wells, based on rising/falling head tests and slug tests. Results StratigraphyFigure 4. Multiport well layout and examples of downhole imagery, caliper log, and gamma log, which were used to establish placement of hydraulically isolated zones in the multiport wells during their construction. Figures 4a-f. Tool used to open and close ports inside wells. Ports consist of a screened section of PVC coupling, which when moved up or down, respectively open or close the casing to formation water. Figures 5a,b. Examples of underdamped and overdamped water level equilibration. Bouwer-Rice (Fig.5a) and Butler (5b) analytical solutions were used to calculate hydraulic conductivities at each port, based on water level response. Figures 6a,b. Head distribution through time, TDS, and hydraulic conductivity in Ruby Ranch (left) and Antioch (right) multiport wells. Zones that experience little change through time indicate lower hydraulic conductivities. TDS values were measured from water samples collected from each zone. Hydraulic conductivity values for the three hydrostratigraphic groupings observed are: Edwards Aquifer, values between 0.3 and 66 ft/day. 26 ft/day avg. Upper Trinity Aquitard, from 0.01 to 0.7 ft/day. 0.25 ft/day avg. Middle Trinity Aquifer, from 0.2 to 37 ft/day. 13.6 ft/day avg. Figures 1 and 2. Wells are located in the Barton Springs Segment of the Edwards Aquifer, within the Balcones Fault Zone. Both wells are about 15 miles south of Austin and 3.5 miles apart. Stratigraphy General HydrostratigraphyHammett Cow Creek Hensel Lower Member Glen Rose Limestone Upper Member Glen Rose Limestone Georgetown Fm. BudaEagle Ford/ Qal?Kainer Fm. Person Fm.200 feetEdwards Group Del RioPorosity/Permeability Hydrologic Function 137.9 Fract oyster wakestone 199.6 fossil (toucasid) vug 238 solutioned fracture 283 solutioned fracture 230 solutioned bedding plane 145.7 stylolites and fractSources Upper Confining Unit Low Low High Low; vertical barrier Low High Locally permeable Low permeable near Edwards contact, decreases with depthSmall et al., 1996 Clark, 2004 Wierman et al., 2010 Good porosity and perm. in bioherms; low porosity and permeability elsewhere Low Moderate; breccia, and moldic (boxwork) texture Fabric selective; Good porosity and permeability in reefs Low High Low; permeable near top Lithology Dense limestone Blue-green to yellow-brown clay Marly limestone; grnst Crystalline limestone; mdst to wkst to milliolid grnst; chert; collapse breccia Milliolid grnst; mdst to wkst; chert Argillaceous mudstone Crystalline limestone; chalky mudstone; chert Mudstone to grainstone; crystalline limestone; chert Shaly, fossiliferous, nodular limestone; mudstone Alt. mdst, wkst, and pkst local solution zones Mudstone, clay and shale Grainstone, dolomitic toward base Mudstone, dolomite, and clay Alt. mdst, clays, wkst and pkst Calcareous mud and vuggy mudstone Calcareous mud and vuggy mudstone Alt wkst, pkst, marl; thick biostromes locally Lower Glen Rose (Clark, 2004): Alt mdst, wkst, pkst, and grnst; bioherms Lower Glen Rose (Wierman et al., 2010) Alternating mdst, wkst, and grnst; lower and upper reef intervals High in biostrome; lower 90 ft very low porosity CU CU AQ confining unit (CU) CU CU Aquifer (AQ) CU AQ AQ AQ AQ in bioherms and evaporite beds, karst and fracture; CU elswhere Karst AQ; not karst CU Karst and fract AQ not karst CU CU; AQ assoc. Karst and fract AQ AQ in reefs AQ assoc. biostromes only AQ Moderate breccia, and moldic (boxwork) texture Confining Units Leached and Collapsed mbrs Dolomitic mbr Kirschberg mbr Grainstone mbr Reg. Dense mbr Basal Nodular mbrEdwards Aquifer Upper Trinity Middle Trinity Confining Unit Lower Cretaceous UpperID thickness in feet Interval A 30-120 Interval B 120-150 Interval C 10-20 ft Interval D 135-180 Interval E 7-10 320-340 ~250 15-40 ~70 ~40 VIII 45-60 VII 110-150 VI 65-75 V 45-60 IV 20-30 III 30-80 I 40-60 50-60 40-50 D West D East ? ? Onion CreekInterstate 35 1100 700 300 100 -100 -200 0 900 1000 800 600 400 200 500Elevation (ft)1100 700 300 100 -100 -200 0 900 1000 800 600 400 200 500Elevation (ft) springEdwards AquiferBrackish EdwardsConfining units 0 1 2 3 Miles Vertical Exaggeration = ~23.5 Edwards Pot. SurfaceKgru Kgrl Kcc Kgru Kgrl Kcc Ruby Multiport Well Antioch Multiport Well References: Bouwer, H., 1989. The Bouwer and Rice slug test--an update, Ground Water, vol. 27, no. 3, pp. 304-309dwards-Trinity Aquifer System, West-Central Texas Butler, J.J., Jr., 1998. The Design, Performance, and Analysis of Slug Tests, Lewis Publishers, New York, 252p. Clark, A.K., 2004, Geologic framework and hydrogeologic characteristics of the Glen Rose limestone, Camp Stanley Storage Activity, Bexar County, Texas Small, T.A., Hanson J.A., Hauwert, N.M., 1996, Geologic Framework and Hydrogeologic Characteristics of the Edwards Aquifer Outcrop (Barton Springs Segment), Northeastern Hays and Soutwestern Travis Counties, Texas Wierman, D.A., Broun, A.S., Hunt, B.B, 2010, Hydrogeologic Atlas of the Hill Country Trinity Aquifer, Blanco, Hays, and Travis Counties, Central Texas Figure 1. Figure 2. Figure 3. Figure 4. Figure 4a. 4b. 4c. 4d. 4e. 4f. Figure 5a. Figure 5b. Figure 6a. Figure 6b. Table 1. Table 2. Z o n e R i s i n g f a l l i n g K ( f t / d a y ) S l u gi n K ( f t / d a y ) S l u g o u t K ( f t / d a y ) Z o n e T h i c k n e s s ( f t ) T r a n s f t 2 / d a y 2 1 0 3 3 5 1 0 2 0 5 3 7 0 3 7 0 0 1 9 5 8 6 3 0 1 4 0 1 8 3 3 2 5 8 4 1 7 3 8 4 4 1 0 5 4 0 0 0 1 6 2 9 8 0 1 9 7 0 2 0 0 0 1 5 2 9 1 0 5 1 6 1 7 5 2 1 0 0 1 4 8 1 0 3 4 5 3 7 0 1 3 4 2 6 4 0 1 6 0 1 2 0 2 8 5 1 1 0 1 9 0 1 0 0 2 1 0 0 2 4 9 0 6 0 1 3 0 1 6 8 0 4 3 0 7 0 3 7 0 6 0 1 0 6 7 0 6 5 0 2 0 2 4 0 8 4 6 7 7 3 0 1 7 0 3 0 2 3 0 5 2 1 1 5 2 2 5 2 6 1 1 9 6 0 5 5 1 0 6 0 Zo n e R i s i n g f a l l i n g K ( / d a y ) S l u g K ( / d a y ) Zo n e T h i c k n e s s ( ) T r a n s m i s s i v i t y ( 2 / d a y ) 1 4 1 3 6 1 3 6 5 7 2 1 3 0 0 0 1 2 2 3 4 4 6 0 1 1 4 1 5 9 8 3 0 0 1 0 0 0 9 1 9 7 5 0 9 0 0 0 5 9 7 4 8 0 7 5 6 5 1 5 7 2 6 6 8 2 1 0 0 0 6 0 4 0 9 7 2 3 6 5 5 0 2 7 7 4 3 7 2 7 3 8 0 0 0 3 2 6 2 6 2 7 0 0 0 2 3 4 2 0 3 6 0 0 0 1 4 1