Nevada Water Science Center


Aquifer Tests

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Phil Gardner
Groundwater Specialist
Phone: (775) 887-7664
Email:pgardner@usgs.gov

 

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Nevada Water Science Center
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Carson City, NV 89701

 

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ER-3-3 m1

Primary Investigator:

Well Data

USGS Site ID
Local Name Altitude (ft) Uppermost
Opening (ft)
Lowermost
Opening (ft)
Primary Aquifer Transmissivity
(ft2/d)
370349116021902 ER-3-3 m1 4054 2630 3193 CARBONATE ROCKS 1.0

 

Aquifer Test

All Aquifer Test Files (zip)

ER-3-3 m1

Aquifer Test (pdf)

Introduction

This memorandum documents the analysis of the ER-3-3 m1 single-well aquifer test in Yucca Flat at the Nevada National Security Site (NNSS). Original goals of the analysis were to estimate the transmissivity of the lower carbonate aquifer (LCA) at well ER-3-3 m1, and to estimate drawdowns in observation wells from a multiple-well aquifer test in well ER-3-3 m1.

The multiple-well aquifer test at well ER-3-3 m1 was reduced to a single-well aquifer test because excessive drawdown occurred in the well even at the lowest rate of pumping (10 gal/min). A network of 27 observation and background wells in Rainier Mesa, Yucca Flat, and Frenchman Flat (Figure 1; Table 1) were instrumented with pressure transducers by a private contractor, Navarro, and the U.S. Geological Survey (USGS). Water levels were monitored for potential drawdowns related to well development and aquifer testing in well ER-3-3 m1. A limited amount of groundwater (about 9,500 gallons) was withdrawn from the LCA during well development and testing. Drawdown was not observed in observation wells distant from the pumping well, resulting in the interpretation of the multiple-well aquifer test as single well.

Borehole ER-3-3 has two main completions and three piezometers. The lower and upper main completions are designated ER-3-3 m1 and ER-3-3 m2, respectively. The deep, intermediate, and shallow piezometers are designated ER-3-3 p1, ER-3-3 p2, and ER-3-3 p3, respectively. The lower main completion, ER-3-3 m1, was pumped for aquifer testing. Piezometers ER-3-3 p1 and ER-3-3 p2 were used as observation wells during aquifer testing. Piezometer ER-3-3 p3 was not monitored because the well is filled with mud. The well completion diagram is provided in Appendix B.

Drawdowns were estimated at 16 distant observation wells using water-level models. Distant observation wells are defined as wells located beyond the pumping well site at ER-3-3. Water-level models were used because potential drawdowns could be masked by environmental water-level fluctuations. No drawdown was estimated at distant observation wells. Water-level model analyses and estimated drawdown results for distant observation wells are discussed in Appendix A.

ER-3-3 is located within the central corridor of underground nuclear testing in Yucca Flat. The borehole is 533 ft southwest of WAGTAIL (U-3an), a large underground nuclear test (UGT) conducted within the saturated zone with an announced yield of 20 to 200 kilotons (U.S. Department of Energy, 2015). The ER-3-3 m1 aquifer test was conducted by Navarro from November to December of 2016 to target the LCA, which is a regional carbonate aquifer that extends from UGT locations in Yucca Flat toward groundwater discharge areas downgradient of the NNSS boundary.

 

Location of ER-3-3 m1 pumping well and network of observation and background wells instrumented during aquifer testing

Figure 1. Location of ER-3-3 m1 pumping well and network of observation and background wells instrumented during aquifer testing. Hydrostratigraphic unit definitions from Prothro and others (2009).

Table 1. Well location and construction data for pumping, observation, and background wells monitored during well ER-3-3 m1 development and testing, Nevada National Security Site.

[Well Name refers to the name of the well in the National Water Information System (NWIS) database, where the bold part of the name is shown on Figure 1. Latitude and Longitude are in decimal degrees and referenced to North American Datum of 1983 (NAD 83); Ground surface altitude is the altitude of the well in ft amsl, feet above National Geodetic Vertical Datum of 1929 (NGVD 29); Depth to static water level is the water-level depth in the well in ft bgs, feet below ground surface; Top of open interval and Bottom of open interval correspond to the depth of the top and bottom of the open interval (i.e., interval that includes well screen, and gravel pack or open hole].

 

Well Name Site Identifier Lat. Long. Ground
surface
altitude,
ft
Depth
to static
water level,
ft bgs
Top of
open
interval,
ft bgs
Bottom
of open
interval,
ft bgs
Radial
distance
from
pumping
well, ft
Pumping Well
ER- 3-3 m1 370349116021902 37.06 -116.04 4,054 1,645 2,630 3,193 0
Observation Wells
ER- 2-1 main (shallow) 370725116033901 37.13 -116.06 4,216 1,725 1,642 2,177 23,526
ER- 2-2 o2 370831116035001 37.14 -116.06 4,273 2,410a 2,008 3,457 29,450
ER- 3-1-2 (shallow) 370116115561302 37.02 -115.94 4,407 2,014 2,208 2,310 33,861
ER- 3-3 p1 370349116021904 37.06 -116.04 4,054 1,645b 2,630 3,193 0
ER- 3-3 p2 370349116021905 37.06 -116.04 4,054 1,653b 2,203 2,507 0
ER- 3-3 p3 370349116021906 37.06 -116.04 4,054 1,444b 118 1,940 0
ER- 4-1 m1 370625116030001 37.11 -116.05 4,158 1,769 2,812 3,035 16,119
ER- 4-1 p1 370625116030002 37.11 -116.05 4,158 1,052 118 2,375 16,119
ER- 5-3-2 365223115561801 36.87 -115.94 3,335 945 4,674 5,683 75,196
ER- 6-1-2 main 365901115593501 36.98 -115.99 3,935 1544 1,775 3,200 31,818
ER- 6-2 365740116043501 36.96 -116.08 4,231 1780 1,746 3,430 38,974
ER- 7-1 370424115594301 37.07 -116.00 4,246 2394 1,775 2,500 12,892
ER-12-1 (1641-1846 ft) 371106116110401 37.18 -116.19 5,817 1,519 1,641 1,846 61,350
TW- 3 364830115512601 36.81 -115.86 3,484 1,104 165 1,860 106,851
TW- 7 370353116020201 37.06 -116.03 4,058 1,646 41 2,272 1,467
TW- D 370418116044501 37.07 -116.08 4,150 1,723 1,700 1,950 11,551
U - 3cn 5 370320116012001 37.06 -116.02 4,009 1,619 2,832 3,030 4,708
UE- 1h 370005116040301 37.00 -116.07 3,995 1,552 2,134 3,358 24,252
UE- 1q (2600 ft) 370337116033002 37.06 -116.06 4,081 1,655 2,459 2,600 6,118
UE- 1r WW 370142116033301 37.03 -116.06 4,042 1,616 2,319 4,182 14,172
UE- 4t 2 (1564-1754 ft) 370556116025406 37.10 -116.05 4,141 868 1,564 1,754 13,150
UE- 7nS 370556116000901 37.10 -116.00 4,367 1,968 1,707 2,205 16,375
UE-10j (2232-2297 ft) 371108116045303 37.19 -116.08 4,574 2,156 2,232 2,297 46,193
WW- 2(3422 ft) 370958116051512 37.17 -116.09 4,470 2,052 2,700 3,422 40,055
WW- A (1870 ft) 370142116021101 37.04 -116.04 4,006 1,599 1,555 1,870 9,715
Background Wells
ER- 8-1 (recompleted) 371248116032102 37.21 -116.06 4,820 2,293 1,947 2,863 54,752
TW- F (3400 ft) 364534116065902 36.76 -116.12 4,143 1,734 3,142 3,392 113,086

Hydrogeology

Yucca Flat is underlain by three types of aquifers: alluvial, volcanic, and carbonate rock. The alluvial aquifers are underlain by a thick sequence of volcanic aquifers and volcanic confining units. Alluvial and volcanic aquifers contribute limited flow to the underlying carbonate aquifer through a volcanic confining unit that acts as a flow barrier (Winograd and Thordarson, 1975).

Alluvial deposits form thin, localized aquifer systems in the Yucca Flat basin. Alluvial aquifers comprise poorly sorted gravels and sands derived from Tertiary volcanic and Paleozoic sedimentary rocks (Slate and others, 1999). Alluvial deposits increase in thickness from the margins to the center of the basin (Bechtel Nevada, 2006), and are unsaturated throughout most of Yucca Flat. However, alluvial aquifers have saturated thicknesses of up to 2,000 ft in areas along the central corridor of Yucca Flat (Fenelon and others, 2012). Observation well WW-A is screened in the alluvial aquifer (Figure 1), and borehole ER-3-3 intersects 1,680 ft of partially saturated alluvial deposits (see well completion diagram in Appendix B).

Volcanic rocks form localized and regionally extensive aquifer systems throughout Yucca Flat. The majority of volcanic rocks were erupted during the Miocene from within the southwestern Nevada volcanic field (Winograd and Thordarson, 1975), which is located to the north and west in the Pahute Mesa—Oasis Valley and Alkali Flat—Furnace Creek Ranch groundwater basins (Figure 1). Regionally extensive volcanic aquifers comprise moderately to densely welded ash-flow tuffs. Localized volcanic aquifers comprise fractured vitric ash-fall tuffs and rhyolitic lava flows. Volcanic aquifers typically have saturated thicknesses that range between 1,000 and 2,500 ft (Fenelon and others, 2012). Observation wells TW-7, UE-4t 2, and ER-3-3 p2 are screened in volcanic aquifers (Figure 1 and 2).

A thick, regionally extensive volcanic confining unit forms a hydraulic barrier between the volcanic aquifers and underlying carbonate aquifer throughout most of the Yucca Flat basin. The volcanic confining unit comprises nonwelded ash-flow tuff, bedded tuff, and reworked tuffaceous sediments that are commonly zeolitized (Winograd and Thordarson, 1975). The saturated thickness of the volcanic confining unit typically ranges between 1,000 and 2,500 ft (Fenelon and others, 2012). The volcanic confining unit is absent in the western part of Yucca Flat, where volcanic aquifers directly overlie the lower carbonate aquifer. Borehole ER-3-3 intersects about 620 ft of the volcanic confining unit overlying the lower carbonate aquifer in the central part of Yucca Flat (see well completion diagram in Appendix B).

Carbonate aquifers form localized and regionally extensive aquifer systems. The regional lower carbonate aquifer (LCA), occurs throughout Yucca Flat and large areas of southern Nevada. The LCA comprises a thick sequence of Paleozoic limestones and dolostones, and has a saturated thickness of more than 15,000 ft in some areas. Pumping well ER-3-3 m1 and the piezometer screened adjacent to the main completion (ER-3-3 p1) are open to 208 ft of the LCA (see well completion diagram in Appendix B), and the majority of observation wells are screened in the LCA (Figure 1).

Data Collection

Pumping for the aquifer test at well ER-3-3 m1 occurred from 11/30/2016 13:40 to 12/15/2016 10:36. During the test, a straddle packer was installed across ER-3-3 m2 to isolate the LCA in ER-3-3 m1. Discharge rates during pumping ranged from 1 to 16 gal/min, and averaged 10 gal/min. A constant-rate test could not be done because pumping rates of 10 gal/min induced excessive drawdown (hundreds of feet of water-level decline) in the well.

Data were collected before, during, and after well development and aquifer testing. Continuously measured data include water levels, water temperature, and barometric pressure at the pumping, observation, and background wells (Table 1), and pumping rates in the pumping well. Water levels and temperature were measured using an INW PT12 pressure transducer, which has a pressure accuracy of + 0.05% of the pressure range. INW PT12 pressure transducers installed in distant observation wells and background wells had a pressure range of 0 to 30 psia, whereas pressure transducers installed in the pumping well and observation wells at borehole ER-3-3 had a pressure range of 0 to 2000 psia. The INW PT12 pressure transducer also has a temperature range of 0° to 55°C (32° to 131°F) with a temperature accuracy of + 0.5°C. Barometric pressure was measured using a PTB110 barometer, which has an accuracy of + 0.3 hPa at 20°C (68°F). A CR1000 Campbell Scientific datalogger collected water levels, water temperature, and barometric pressure every 10 minutes or if a change greater than 0.05 psi occurred. The Foxboro 8002A series flowmeter was used to measure pumping rates, which has a flow rate range of 13 to 250 gal/min and a flow rate accuracy of 0.029%. The pumping schedule for well ER-3-3 m1 is shown in Figure 2.

Pumping schedule of well ER-3-3 m1 during aquifer testing at Yucca Flat, November—December 2016

Figure 2. Pumping schedule of well ER-3-3 m1 during aquifer testing at Yucca Flat, November—December 2016.

Estimated Drawdowns

Drawdowns only were detected in observation wells at the pumping well site. ER-3-3 p1, open to the LCA in the pumped interval, had drawdowns that exceeded 200 ft (Figure 3). ER-3-3 p2, open to welded and vitric tuffs above the pumped interval, had drawdowns of less than 1 ft (Figure 4). No drawdowns were estimated at observation wells not located at the pumping well site. Water-level model analyses and estimated drawdown results for distant observation wells are discussed in Appendix A.

Depth-to-water in ER-3-3 p1 and groundwater withdrawal rates in ER-3-3 m1 during aquifer testing

Figure 3. Depth-to-water in ER-3-3 p1 and groundwater withdrawal rates in ER-3-3 m1 during aquifer testing.
Depth-to-water in ER-3-3 p2 and groundwater withdrawal rates in ER-3-3 m1 during aquifer testing.

Figure 4. Depth-to-water in ER-3-3 p2 and groundwater withdrawal rates in ER-3-3 m1 during aquifer testing.

Aquifer Test Analysis

Drawdown in piezometer ER-3-3 p1 was interpreted as a slug test with the Bouwer and Rice method (Bouwer and Rice, 1976). The Bouwer and Rice method was selected because excessive drawdown occurred in the well even at the lowest rate of pumping (10 gal/min), causing water levels to draw down below the pump intake. Pumping in the well can be interpreted as a series of slug tests, where the well was "bailed" and water levels recovered (Figure 3). The Bouwer and Rice method is appropriate for the analysis because the method can be applied to confined aquifers (Bouwer, 1989). Piezometer ER-3-3 p1 is open to a confined part of the LCA, and the Bouwer and Rice method yields superior estimates of hydraulic conductivity compared to other confined analytical slug-test solutions for partially penetrating wells (Brown and others, 1995). However, unlike a typical slug test, the wellbore contains a pump string, where the volume of the pump string is removed in the analysis by computing an effective casing diameter of the well (see slug test analysis in Appendix B for details).

The estimated hydraulic conductivity of the LCA is 0.01 ft/d (Figure 5). The period of analysis for estimating transmissivity spans from 12/05/16 10:01 to 12/05/16 12:05. Estimated hydraulic conductivity from this 2.1 hour (0.09 day) period of analysis is similar to other recovery periods. Using the interval of the well screen open to the LCA as the aquifer thickness (L = 80 ft), the estimated transmissivity of the LCA is 1 ft2/d.

Two factors likely contribute to the low transmissivity estimated for the LCA at ER-3-3: the majority of the open interval is screened across confining units and the well screen is partially clogged with drilling mud. The open interval at ER-3-3 m1 is screened in about 105 ft of nonwelded tuff, 250 ft of paleocolluvium, and 208 ft of Paleozoic dolomite. The nonwelded tuff and paleocolluvium are assumed to have little to no contribution to the total estimated transmissivity because these rocks are low permeability confining units (Fenelon and others, 2012). The Paleozoic dolomite is assumed to contribute significantly to the total estimated transmissivity; however, only 80 ft of the well screen is hydraulically connected to the dolomite. A well screen length of 80 ft was selected, even though ER-3-3 p1 is open to 208 ft of the LCA, because the well screen was emplaced in about 128 ft of drilling mud.

Period of analysis for estimating transmissivity spanning from 12/05/16 10:01 to 12/05/16 12:05 (2.1 hours); and (B) Normalized drawdowns and straight-line approximation in well ER-3-3 p1 during pumping in well ER-3-3 m1

Figure 5. (A) Period of analysis for estimating transmissivity spanning from 12/05/16 10:01 to 12/05/16 12:05 (2.1 hours); and (B) Normalized drawdowns and straight-line approximation in well ER-3-3 p1 during pumping in well ER-3-3 m1.

REFERENCES

Bechtel Nevada, 2006, A hydrostratigraphic model and alternatives for the groundwater flow and contaminant transport model of Corrective Action Unit 97-Yucca Flat-Climax Mine, Lincoln and Nye Counties, Nevada: U.S. Department of Energy Report DOE/NV/11718-1119, 288 p.

Bouwer, H., 1989. The Bouwer and Rice slug test--an update, Ground Water, vol. 27, no. 3, pp. 304-309.

Bouwer, H. and R.C. Rice, 1976. A slug test method for determining hydraulic conductivity of unconfined aquifers with completely or partially penetrating wells, Water Resources Research, vol. 12, no. 3, pp. 423-428.

Brown, D.L. T.N. Narasimhan and Z. Demir, 1995. An evaluation of the Bouwer and Rice method of slug test analysis, Water Resources Research, vol. 31, no. 5, pp. 1239-1246.

Fenelon, J.M., Sweetkind, D.S., Elliott, P.E., and Laczniak, R.J., 2012, Conceptualization of the Predevelopment Groundwater Flow System and Transient Water-Level Responses in Yucca Flat, Nevada National Security Site, Nevada: U.S. Geological Survey Scientific Investigations Report 2012-5196, 72 p.

Garcia, C.A., Halford, K.J., and Fenelon, J.M., 2013, Detecting drawdowns masked by environmental stresses with water-level models, Groundwater, 51: 322 - 332.

Halford, K., Garcia, C.A., Fenelon, J., and Mirus, B., 2012, Advanced methods for modeling water-levels and estimating drawdowns with SeriesSEE, an Excel add-In, (ver. 1.1, July, 2016): U.S. Geological Survey Techniques and Methods 4-F4, 28 p., http://dx.doi.org/10.3133/tm4F4.

Harrison, J.C., 1971, New computer programs for the calculation of earth tides: Cooperative Institute for Research in Environmental Sciences, National Oceanic and Atmospheric Administration/University of Colorado.

Prothro, L.B., Drellack, S. L., and Mercadante, J.M., 2009, A Hydrostratigraphic System for Modeling Groundwater Flow and Radionuclide Migration at the Corrective Action Unit Scale, Nevada Test Site and Surrounding Areas, Clark, Lincoln, and Nye Counties, Nevada: National Security Technologies, LLC., Las Vegas, Nevada, 145 p.

Slate, J.L, Berry, M.E., Rowley, P.D., Fridrich, C.J., Morgan, K.S., Workman, J.B., Young, O.D., Dixon, G.L., Williams, V.S., McKee, E.H., Ponce, D.A., Hildenbrand, T.G., Swadley, W.C., Lundstrom, S.C., Ekren, E.B., Warren, R.G., Cole, J.C., Fleck, R.J., Lanphere, M.A., Sawyer, D.A., Minor, S.A., Grunwald, D.J., Laczniak, R.J., Menges, C.M., Yount, J.C., and Jayko, A.S., 1999, Digital geologic map of the Nevada Test Site and vicinity, Nye, Lincoln, and Clark Counties, Nevada, and Inyo County, California: U.S. Geological Survey Open-File Report 99-554A, 53 p., 1 pl., scale 1:120,000, accessed June 2011 at http://pubs.usgs.gov/of/1999/ofr-99-0554/.

U.S. Department of Energy, 2015, United States nuclear tests, July 1945 through September 1992: U.S. Department of Energy Report DOE/NV--209 REV 16, 129 p.

Winograd, I.J., and Thordarson, William, 1975, Hydrogeologic and hydrochemical framework, south-central Great Basin, Nevada-California, with special reference to the Nevada Test Site: U.S. Geological Survey Professional Paper 712-C, 126 p.

 

Appendix A. Estimated Drawdowns in Distant Observation Wells

Appendix A contains the estimated drawdown analysis of 16 distant observation wells monitored during the ER-3-3 m1 aquifer test. The first part of this appendix discusses data collection and the water-level modelling methodology used to estimate drawdown. The water-level modelling discussion is followed by 16 hydrographs showing water-level model results. Hydrographs compare measured and synthetic water-level change, and show residuals, estimated drawdown, and groundwater withdrawals during aquifer testing at well ER-3-3 m1. Hydrographs are presented for observation wells distant from the pumping well, where no drawdown was detected.

Data Collection

Water levels were analyzed for drawdown from pumping well ER-3-3 m1 at 16 observation wells: ER-2-1 m, ER-2-2, ER-3-1-2, ER-5-3-2, ER-6-1-2 m, ER-6-2, ER-7-1, TW-D, TW-7, U-3cn 5, UE-1h, UE-1q, UE-7nS, UE-10j, WW-2, and WW-A. These wells are closest to borehole ER-3-3, are screened across a range of hydrostratigraphic units, and exist in opposing quadrants from the pumping well (Figure 1). The selection of distant observation wells analyzed for drawdown was sufficient to understand hydraulic connections within the LCA and between the LCA and volcanic-rock aquifers.

Water levels in observation wells UE-1r, UE-4t 2, ER-3-3 p3, ER-4-1 m1, and ER-4-1 p1 were removed from the analysis. Continuous water-level measurements in UE-1r began 5 days prior to well ER-3-3 m1 development and aquifer testing, which did not provide a sufficient antecedent period for estimating small drawdown that would otherwise be masked by environmental noise. Continuous water-level data in well UE-4t 2 had an anomalously rising trend during well development and testing that is not representative of the aquifer system. Because the pressure transducer in ER-4-1 m1 was removed during well ER-3-3 m1 development and aquifer testing, this well was not used in the drawdown analysis. Well ER-4-1 p1 recently was drilled and water levels currently are recovering following well construction; therefore, water levels are not representative of the aquifer system. Water levels were not measured in ER-3-3 p3 during the period of aquifer testing in ER-3-3 m1 because the piezometer is filled with drilling mud.

Drawdown Estimation Using Water-Level Models

Drawdowns from pumping well ER-3-3 m1 were estimated by modeling water levels in observation wells as described by Halford and others (2012). Water-level modeling was used to estimate drawdown because environmental (non-pumping) water-level fluctuations of more than 0.2 ft could potentially mask drawdown from pumping in observation wells. Potential drawdown was differentiated from environmental fluctuations by modeling synthetic water levels that simulated environmental water-level fluctuations and the pumping signal.

Environmental water-level fluctuations were simulated using time series of barometric pressure, earth and gravity tides, and water levels from background wells TW-F and ER-8-1. The background wells are assumed to be close enough to the observations wells to be affected by similar environmental fluctuations, yet distant enough to be unaffected by pumping from aquifer testing. Water levels from background wells were critical because they were affected by tidal potential-rock interaction, barometric pressure, and seasonal climatic trends. These effects also are assumed present in the observation wells.

Responses from pumping well ER-3-3 m1 were modeled with a Theis transform of the pumping signal, where multiple pumping rates were simulated by superimposing multiple Theis (1935) solutions. Theis transforms serve as simple transform functions, where step-wise pumping records are translated into approximate water-level responses. Numerical experiments have confirmed that superimposed Theis transforms closely approximate water-level responses through hydrogeologically complex aquifers (Garcia and others, 2013).

Synthetic water levels were fit to measured water levels by minimizing the Root-Mean-Square (RMS) error of differences between synthetic and measured water levels (Halford and others, 2012). Amplitude and phase were adjusted in each time series used to simulate environmental water-level fluctuations (barometric pressure, water levels in background wells, and earth and gravity tides). Transmissivity and the storage coefficient were adjusted in the Theis transform.

Drawdown estimates are the summation of Theis transforms minus residual differences between synthetic and measured water levels (Halford and others, 2012). The summation of all Theis transforms is the direct estimate of the pumping signal. Residuals represent all unexplained water-level fluctuations. These fluctuations primarily are random during non-pumping periods, but can contain unexplained components of the pumping signal during pumping periods.

All synthetic water levels in the water-level models represented summed time series of earth tides, gravity tides, barometric pressure, background water levels, and pumping responses. Earth and gravity tides were computed functions based on well-established theoretical equations (Harrison, 1971). Barometric pressure typically was measured at the well being analyzed and/or at the background well. Pumping responses were simulated with Theis transforms that used simplified pumping schedules in ER-3-3 m1. Pumping in well ER-3-3 m1 was approximated using 198 simplified pumping steps. These simplified steps were sufficient to calculate the pumping response in observation wells with the Theis transform models. Total withdrawal during the period of well development and testing was less than 10,000 gallons (~1,337 ft3).

Water levels were modeled from October 1, 2016 to January 15, 2017 to estimate drawdowns at 16 distant observation wells monitored before, during, and after the aquifer test. Synthetic water levels matched measured water levels with RMS errors between 0.003 and 0.020 ft in observation wells. Drawdown was not detected in any distant observation well, as shown in the hydrographs below. Worksheets showing fitting parameters, measured and synthetic water levels, and drawdown estimates for analyzed wells are in individual Excel files in Appendix B.

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

Graph of groundwater withdrawals

 

Appendix B. Water-Level Models, Slug Test Analysis, and Supporting Datasets

Water-level models, the slug test analysis, and supporting datasets are in the compressed (zip) file, AppendixB. The zip file contains 4 directories: (1) CleanData; (2) SlugTest; (3) WellCompletionDiagram; and (4) WLM.

The CleanData directory contains time series data used to estimate drawdowns and aquifer transmissivity. Time series data include observation-, pumping-, and background-well water levels and barometric pressure, and pumping rates for ER-3-3 m1. Raw data were obtained from Navarro. For each of the observation and background wells, a Microsoft© Excel workbook contains hourly averages of water level and barometric pressure data. Bad values (values equal to 99999 or 0) were removed from the time series data prior to averaging.

The SlugTest directory contains a macro-enabled Microsoft© Excel workbook that was used to estimate the transmissivity of the lower carbonate aquifer at ER-3-3. The COMPUTATION worksheet contains formulas used to compute aquifer hydraulic conductivity and transmissivity using the Bouwer and Rice (1976) method. The DEFAULT PROPERTIES and SETTINGS worksheet contains a reference table of extreme and likely ranges of hydraulic conductivity for different aquifer materials. The OUTPUT worksheet is used to input well construction information for computing hydraulic properties, and shows a semi-log displacement-time plot for the Bouwer and Rice analysis of the ER-3-3 m1 aquifer test. The DATA worksheet is used to input water-level data for computing hydraulic properties. The EFFECTIVE DIAMETER worksheet contains the computation of the effective casing diameter.

The WellCompletionDiagram directory contains a Portable Document File (PDF) showing the well completion of borehole ER-3-3. Well completion diagram was modified from Navarro (written communication, 2017).

The WLM directory contains 16 water-level models (macro-enabled Microsoft Excel workbooks) for water-level records from the 16 observation wells located away from the pumping site. Water-level models were generated using a Microsoft© Excel add-in, SeriesSEE (Halford and others, 2012). Each Microsoft© Excel workbook has three worksheets: DATA, Series, and WLmodel. The DATA tab contains the time-series data used in the water-level model. Data include time series of water levels from the observation well and background well(s), barometric pressure at the observation and (or) background well(s), and pumping data. The Series tab contains the time series used in the water-level model. Time series include moving averages of water levels and barometric pressure in background wells, Theis transforms of pumping in well ER-3-3, and time series of gravity tides (in microgals) and solid Earth tides (dry dilation in ppb). Measured, synthetic, residuals, and estimated drawdown time series also are included in this worksheet. The WLmodel tab shows the parameters used in the water-level model, a plot of measured versus synthetic water levels and residuals, and the overall RMSE.

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