Prepared in cooperation with California State Water Resources Control Board

Multiple-Well Monitoring Site Adjacent to the Lost Hills Oil 

Field, Kern County, California

U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2019–1114

February 2020

The U.S. Geological Survey (USGS), in cooperation with the California State 

Water Resources Control Board, is evaluating several questions about oil and gas 

development and groundwater resources in California, including (1) the location of 

groundwater resources; (2) the proximity of oil and gas operations and groundwater and 

the geologic materials between them; (3) evidence for or against fluids from oil and gas 

sources in groundwater; and (4) the pathways or processes responsible when fluids from 

oil and gas sources are present in groundwater (U.S. Geological Survey, 2019). As part 

of this evaluation, the USGS installed a multiple-well monitoring site in the southern 

San Joaquin Valley near Lost Hills, California, adjacent to the Lost Hills oil field 

(fig. 1). Data collected at the Lost Hills multiple-well monitoring site (LHSP) provide 

information about the geology, hydrology, geophysics, and geochemistry of the aquifer 

system, thus enhancing understanding of relations between adjacent groundwater and 

the Lost Hills oil field in an area where there is little groundwater data. This report 

presents construction information for the LHSP and initial geohydrologic data collected 

from the site.

Study Area

The LHSP is in the Kern 

County subbasin of the San Joaquin 

Valley groundwater basin situated 

on the southern end of the Tulare 

Lake Hydrologic Region (California 

Department of Water Resources, 2016; 

fig. 1). The LHSP is approximately 

1,400 feet (ft) east and downgradient 

from the Lost Hills oil and gas field 

administrative boundary.

Primary water-bearing units that 

comprise the major aquifers on the 

west side of the Tulare Lake region 

include alluvial and river sediments 

of Holocene age, older alluvium and 

terrace deposits of Pleistocene age, 

and Pliocene-Pleistocene-age Tulare 

Formation (Woodring, 1940; California 

Department of Water Resources, 2015). 

ISSN 2331-1258 (online)

https://doi.org/10.3133/ofr20191114

Figure 1. Location of Lost Hills multiple-well monitoring well site (LHSP) and selected other 

wells in relation to the Lost Hills oil field, Kern County, California.

120° 45' 30'

45'

35°37'30"

Base modified from U.S. Geological Survey and other Federal and State digital data, 

various scales; Albers Equal-Area Conic projection, standard parallels are 29°30’ N. 

and 45°30’ N.; North American Datum of 1983

Oil and gas well data from the California Department of Conservation, 2018.

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

46

33 5

s!

CALIFORNIA

Sacramento

San Diego

Kern County

subbasin

Tulare Lake

Hydrologic

Region

San Joaquin Valley

groundwater basin

Bakersfield

LHSP

Lost Hills

Lost Hills multiple-well monitoring site (LHSP) 

County boundary

Oil and gas field administrative boundary

Disposal well

Injection well

Oil and gas production well

Plugged or buried well

Area of historical produced water storage

EXPLANATION

s!

KERN COUNTY

TULARE COUNTY

Modesto

Corcoran
Most groundwater studies of the Central 

Valley define hydrogeologic units—

aquifers and confining layers, rather than 

stratigraphic units (Faunt, 2009). At the 

LHSP, the stratigraphic units are defined; 

therefore, the aquifer system is discussed 

as the alluvial and Tulare aquifer systems 

even though they function regionally as 

a single water-yielding unit. Numerous 

lenses of fine-grained sediments are 

distributed throughout the San Joaquin 

Valley; these generally constitute more 

than 50 percent of the total thickness 

of the valley fill (Faunt, 2009). Faunt 

(2009) also noted that sediments in the 

western part of the San Joaquin Valley 

are generally finer-grained than sediments 

located to the east.

The primary confining unit in 

the aquifer system of the Tulare Lake 

Hydrologic Region is the Corcoran 

Clay (Frink and Kues, 1954) and its 

equivalent, the E-clay of Croft (1972). 

For the purposes of this brief discussion, 

the Corcoran Clay and the Corcoran 

Clay equivalent are simply referred to as 

the Corcoran Clay. The Corcoran Clay 

underlies approximately the western 

two thirds of the San Joaquin Valley 

extending from the southern edge of the 

valley, near Kern Lake (not shown), to 

north of Modesto (Faunt, 2009). The 

Corcoran Clay is thicker in an area 

between Lost Hills and Corcoran, located 

about 35 miles (mi) to the north, and 

may be as thick as 200 ft approximately 

14 mi north of Lost Hills (Faunt, 2009). 

The Corcoran Clay is between 272 and 

338 feet below land surface (ft bls) at 

the LHSP. Locally, Faunt (2009) and 

Gillespie and others (2019b) show the 

western edge of the clay is generally 

coincident with the eastern edge of the 

Lost Hills oil and gas field.

The LHSP location was selected 

to provide better information regarding 

vertical and lateral changes in 

groundwater gradients and water quality 

of the alluvial and Tulare aquifer system. 

The site is located east of the Lost 

Hills field and downgradient from the 

intensively developed oil field where 

the potential presence of oil-field fluids 

in overlying and adjacent groundwater 

zones exist either from naturally 

existing oil and gas shows in aquifers 

in proximity to oil fields or resulting 

from a range of historical and current oil 

and gas development activities. These 

activities include surface spills, leakage 

of produced water from disposal ponds, 

injection of fluids into the subsurface for 

enhanced recovery and produced-water 

disposal, and potential introduction of 

preferential pathways through leaky or 

improperly abandoned oil and gas wells 

or test holes (Davis and others, 2018a; 

Gillespie and others, 2019b). 

The land surface and confining clay 

layers slope downward gradually from 

the Lost Hills oil field toward the LHSP 

borehole (Gillespie and others, 2019b). 

The LHSP is approximately 4,500 ft 

from the nearest active oil well, 4,500 ft 

from the nearest active steam flood well 

(injection of steam for enhanced recovery 

of oil), 6,000 ft from the nearest produced 

water disposal well, and 7,000 ft from 

the nearest water flood well (injection of 

produced water for enhanced recovery 

of oil). There is a high concentration of 

oil-production activities near the LHSP. 

Activities within 2 mi to the south and 

west of the LHSP include 22 waterdisposal wells, 1,020 steam-flood wells, 

and 22 water-flood wells that are active, 

inactive, or new; 1,480 oil- or gasproduction wells that are active, inactive, 

or new; 832 wells that are plugged or 

buried; and 3 areas where produced 

water-storage ponds have been or are 

currently located (California Department 

of Conservation, 2018).

Drilling and Well Installation

The LHSP pilot borehole, with a 

diameter ranging from 8 1/

2

 to 7 5/

8 inches, 

was drilled to a depth of 1,880 ft 

bls during March 2018 using direct 

mud-rotary drilling techniques. Drill 

cuttings were collected throughout the 

drilling process and analyzed (along 

with notes from the on-site geologist) 

to summarize the lithology (fig. 2) 

following the procedures described by 

Everett and others (2013). To assist 

in the identification of lithologic and 

stratigraphic units, geophysical logging 

of the borehole was done before well 

construction using techniques described 

by Keys and MacCary, 1971; Shuter 

and Teasdale, 1989; Keys, 1990; and 

Kenyon and others, 1995. Geophysical 

logs completed at the site include caliper, 

natural gamma, resistivity (16- and 

64-inch), spontaneous potential (SP), 

electromagnetic induction (conductivity), 

full wave sonic (delta-T), and Nuclear 

Magnetic Resonance (NMR) porosity 

(fig. 2). Logging in the small-diameter 

pilot hole was advantageous because 

it allowed for higher-quality logs to be 

collected than in the larger diameter 

holes. Well-screen and filter-pack 

intervals were selected based on the 

geophysical and lithologic data. The 

pilot hole was then reamed to increase 

the borehole diameter to allow for the 

construction of the five-well monitoring 

site. The deepest well (LHSP #1) was 

constructed with 2.5-inch-diameter 

polyvinyl chloride (PVC) casing to allow 

for future geophysical logging, and the 

shallower four wells were constructed 

with 2-inch-diameter PVC casing. The 

wells were installed with screened 

intervals from 1,780 to 1,800 (LHSP 

#1); 1,110 to 1,130 (LHSP #2); 700 to 

720 (LHSP #3); 490 to 510 (LHSP #4); 

and 210 to 230 (LHSP #5) ft bls (fig. 2; 

table 1). A filter pack of #3 sand was 

installed around each screen, and a lowpermeability bentonite grout was placed 

in the depth intervals between the filter 

packs to isolate each of the wells.

After construction was completed, 

the wells were developed by using 

airlifting and a surging technique with 

compressed air to remove drilling fluid 

and develop the filter pack surrounding 

each monitoring well. The field 

parameters that were recorded during the 

process include specific conductance, pH, 

water temperature, apparent color, and 

turbidity. Well development continued 

until no discernible drilling mud was 

present and field parameters were 

stabilized. The average flow rate and 

development time was used to estimate 

the total discharge and total purge 

volumes of the casing and sand pack 

(table 2). After well development, the 

turbidity of all wells, except LHSP #1, 

was below 10 nephelometric turbidity 

units (NTU; table 2). The higher turbidity 

in LHSP #1, 105 NTU, is assumed to 

be a result of the formation because 

the appearance of the water resembled 

the color of the clays and silts of the 

formation/cuttings samples collected 

during drilling.
Figure 2. Well construction, summary lithology, and geophysical log data from Lost Hills multiple-well monitoring site (LHSP), Kern County, 

California. (Abbreviations: API, American Petroleum Institute units; RES, resistivity; SP, spontaneous potential; 16N, 16-inch normal; NMR, 

Nuclear Magnetic Resonance; OHM-M, ohm-meter; 64N, 64-inch normal; MV, millivolt; MMHO/M, millimho per meter; %, percent; V/V, volume 

per volume).

Natural gamma Well construction

API

Caliper SP

–20 Inch 20 0 200 0 20 –280 MV –180 0 80 0 % 100 10 10

Resistivity (16N)

OHM-M

0 0 900 0 V/V 0.8 0 % 100

0 % 100

OHM-M 20

Sonic porosity

%

Clay-bound

fluid volume Lithology summary

Corcoran Clay equivalent

Alluvial

deposits

Tulare Formation San

Joaquin

 Formation

Middle Tulare clay

Amnicola clay

Electromagnetic 

conductivity

MMHO/M

Resistivity (64N)

Capillary-bound

fluid volume

Mobile fluid volume

100

200

300

400

500

600

700

800

900

1,000

1,100

1,200

1,300

1,400

1,500

1,600

1,700

1,800

Total fluid volume

Depth, ft

below land

surface

Gravelly, sandy, silty clay

Clay with silty sand

Sand with silt

Silty clay

Silty clay

Silty clay

Sand with silt

Silty clay

Gravelly, silty sand

Sand with silt and clay

Silty clay with sand

Silty clay with sand

Gravelly, clayey, and silty sand

Sand with silt and clay

Gravelly sand

Silty sand with shell fragments

Clayey, silty sand

Silty clay

Silty sand with shell fragments

Sandy, silty clay

Silty clay with shells

Silty clay

Clayey, silty sand

Sandy silt

Silty clay

Silty sand

Silty clay with wood and shell 

fragments

Silty clay with sand

Sandy, silty clay

Clay with silt and gravel

Clay with silt

LHSP #4LHSP #2LHSP #1LHSP #3LHSP #5

( is depth to water,

May 30, 2018)

170’

246’

455’

535’

675’

743’

1,080’

1,160’

1,758’

1,805’

0
Geology

The lithology at the site consists 

of unconsolidated terrestrial deposits of 

gravels, sands, silts, and clays (fig. 2) 

in the alluvial deposits and the Tulare 

Formation, and marine silts and clays of 

the underlying San Joaquin Formation. 

The lithology at this location is primarily 

fine grained and is consistent with 

observations by Page (1983) that the 

Tulare Formation along the western edge 

of the southern San Joaquin Valley is 

fine grained, particularly at depth. The 

contact between the alluvial deposits and 

the Tulare Formation is thought to be 

at 237 ft bls based on changes in color 

of the sediment from light yellowish 

brown to olive gray and an abrupt change 

in the SP log; however, as noted by 

Wood and Davis (1959), it is difficult 

to distinguish the alluvial deposits from 

the upper Tulare in this region. The 

depths to the top and bottom contacts 

of the several prominent clay layers 

underlying the LHSP are more apparent 

based on characteristic shifts in borehole 

geophysical logs observed across the area 

(Gillespie and others, 2019b) and are 

identified as (all depths ft bls) Corcoran 

Clay equivalent, 272–338 ft; middle 

Tulare clay, 547–562 ft; and Amnicola 

clay, 938–1,079 ft. The base of the Tulare 

Formation is estimated at 1,807 ft bls 

based on borehole log interpretation 

(Gillespie and others, 2019a).

Shell and wood fragments were 

observed at several depths (fig. 2). Shell 

fragments observed between 693 and 

860 ft bls were too small to identify 

by using photographs of type shells 

but are thought to be Anodonta. Shells 

observed between 938 and 1,079 ft bls 

were identified as Amnicola based on 

descriptions of Woodring and others 

(1940). Shell fragments observed 

between 1,344 and 1,426 ft bls were 

not identified.

Hydrology

Aquifer Tests

The hydraulic conductivity of the 

aquifer material adjacent to the screened 

interval was estimated from pneumatic 

slug tests completed on each of the 

wells. Compressed nitrogen gas (N2) 

was used to depress the water level in 

the well by using a pressure regulator 

and well-head apparatus following 

procedures similar to Leap (1984) and 

Greene and Shapiro (1995). Induced 

declines in water levels were hundreds 

of feet above the perforations so that 

no nitrogen gas entered the formation 

through the perforations. Multiple 

tests were generally completed in each 

well, and average values are shown 

in table 3. Aquifer properties analysis 

was completed using AQTESOLV 

software (Duffield, 2007) and the Kansas 

Geological Survey (KGS) Model package 

for overdamped slug tests in partially 

penetrating wells in a confined aquifer 

(Hyder and others, 1994).

Table 2. Well development and water-level data from Lost Hills multiple-well monitoring site (LHSP), Kern County, California.

[Wells ordered from shallowest to deepest. Abbreviations: ft bls, feet below land surface; gal/min, gallons per minute; gal, gallon; v/v, volume per volume; 

NTU, nephelometric turbidity units]

Common 

well 

name

Predevelopment 

depth to water 

(ft bls)

Post development 

depth to water 

(ft bls) 

(5/30/18)

Average flow 

(gal/min)

Hours of 

development

Estimated total 

discharge 

(gal)

Purge per 

casing volume 

(v/v)

Purge per sand 

pack volume 

(v/v)

Post 

development 

turbidity 

(NTU)

LHSP #5 43.26 44.15 6.3 28 9,200 307 34 5.4

LHSP #4 264.41 264.83 5.0 6 1,100 29 5.6 2.2

LHSP #3 277.08 276.82 6.5 14 6,900 97 49 6.8

LHSP #2 261.86 261.41 7.1 30 11,200 81 58 2.7

LHSP #1 222.80 219.73 1.3 208 12,600 32 65 105

Table 1. Identification and construction information from Lost Hills multiple-well monitoring site (LHSP), Kern County, California.

[See figure 1 for well locations. Wells ordered from shallowest to deepest. The fifteen-digit U.S. Geological Survey (USGS) site identification number is 

used to uniquely identify the well. The common name is used throughout the report for quick reference. Land-surface datum (LSD) is a datum plane that 

is approximately at land surface at each well. The altitude of the LSD is described in feet above the North American Vertical Datum of 1988 (NAVD 88). 

Abbreviations: NWISWeb, National Water Information System Web site; ft, feet; ft bls, feet below land surface]

Common 

well name

USGS site 

identification 

number 

(hyperlinked to 

NWISWeb)

Altitude 

of LSD 

(ft above NAVD88)

Well 

diameter 

(inside, inches)

Depth to 

bottom of well 

(ft bls)

Depth to top 

of perforations 

(ft bls)

Depth to bottom 

of perforations 

(ft bls)

LHSP #5 354048119445005 272.55 1.94 230 210 230

LHSP #4 354048119445004 272.55 1.94 510 490 510

LHSP #3 354048119445003 272.55 1.94 720 700 720

LHSP #2 354048119445002 272.55 1.94 1,130 1,110 1,130

LHSP #1 354048119445001 272.55 2.32 1,860 1,780 1,800
LHSP #4 indicates that the Corcoran Clay 

equivalent, which separates these two 

wells, is an effective aquitard separating 

overlying and underlying aquifer layers 

at this location. Before installation of 

the LHSP, there were no available data 

on vertical profiles of groundwater flow 

across the full thickness of the alluvial 

and Tulare aquifer system near the Lost 

Hills oil field.

Water-level changes that happened 

over time were used to help determine the 

degree of hydraulic interaction between 

aquifer layers that are 

restricted by confining 

clay layers. The change 

in water level for each 

well relative to May 31, 

2018, at 3:00 p.m. 

Pacific daylight time 

(PDT) was calculated 

(fig. 4). During the 

period between May 31, 

2018, and January 30, 

2019, a water-level rise 

of 10 ft was observed in 

LHSP #1, the deepest 

well, and a slight rise 

of about 1.5 ft was 

observed in LHSP #5, 

the shallowest well. 

A slight decline of 

1.5 ft was observed in 

LHSP #2 during the 

same period. Between 

May 31, 2018, and midNovember 2018, declines 

of approximately 7.5 and 

11.0 ft were observed in 

LHSP #3 and LHSP #4. 

After December 1, 2018, 

water levels in both wells 

rose through the period 

of record. The decline 

and recovery observed in LHSP #3 

and LHSP #4 is expected for aquifer 

layers affected by seasonal groundwater 

withdrawals, which could be regional or 

local. Water levels typically decline in 

the summer due to increased water use 

and groundwater withdrawal, and they 

recover in the winter in correlation with 

decreased withdrawal and increased 

recharge from precipitation. Larger 

summer declines and earlier recovery 

of water levels in LHSP #4 compared to 

LHSP #3 indicated that the layer in the 

Hydraulic conductivity estimates 

ranged from 0.02 foot per day (ft/day; 

LHSP #1) to 6 ft/day (LHSP #3; table 3; 

Everett and others, 2019). The deepest 

well, LHSP #1, is completed in silty clay 

at the base of the Tulare Formation where 

a low hydraulic conductivity is expected. 

The values in overlying wells were in the 

range of values expected for sand with 

gravel, silt, and clay, although the value 

at LHPSP #4 of 1 ft/day was at the low 

end of typical values (Heath, 1983).

Water Levels

Water-level data collected included 

periodic discrete manual measurements 

and hourly data recorded by downhole 

pressure transducers. Methods described 

by Cunningham and Schalk (2011) 

were used to collect and quality-assure 

the water-level records. The data were 

analyzed to identify vertical water-level 

gradients, which indicate direction and 

variability of potential groundwater flow 

between aquifer layers and responses 

to factors such as recharge and local 

groundwater withdrawal.

The vertical water-level gradients at 

the site calculated from multiple discrete 

water-level measurements collected on 

May 30, 2018 (table 2), indicated that 

groundwater should flow downward 

from the top and upward from the bottom 

toward the middle of the Tulare aquifer 

system. The groundwater gradient was 

downward to a depth of approximately 

600 ft with a maximum gradient of 

–0.788 foot per foot (ft/ft) between 

LHSP #5 and LHSP #4. Between 600 

and 1,800 ft, the gradient was upward 

with a maximum of 0.062 ft/ft between 

LHSP #1 and LHSP #2 (fig. 3). The 

steep gradient between LHSP #5 and 

Table 3. Summary results of slug tests from Lost Hills multiple-well monitoring site (LHSP), Kern County, California. 

[Wells ordered from shallowest to deepest. Abbreviations: ft bls, feet below land surface; ft, feet; lbs/in2, pounds per square inch; ft/day, feet per day; 

KGS, Kansas Geological Survey] 

Common 

well 

name

Screened 

section 

(ft bls)

Static water 

level at start 

of test 

(ft bls)

Static water 

level at end 

of test 

(ft bls)

Change in 

static water level 

during test 

(ft)

Method of 

analysis

Pressures 

(lbs/in2)

Number of 

tests included 

in average

Hydraulic 

conductivity 

(ft/day)

LHSP #5 210–230 44.15 44.16 –0.01 KGS Model 5, 10 3 4

LHSP #4 490–510 264.83 264.86 –0.03 KGS Model 5, 10 3 1

LHSP #3 700–720 276.82 276.86 –0.04 KGS Model 5, 10 3 6

LHSP #2 1,110–1,130 261.41 261.45 –0.04 KGS Model 5, 10 4 4

LHSP #1 1,780–1,800 219.73 219.74 –0.01 KGS Model 5 1 0.02

0 100 200 300

Depth to water, in feet below land surface, May 30, 2018

Water level versus well depth 0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

Depth to top of perforation interval, in feet below land surface

Corcoran Clay equivalent 

LHSP #1

LHSP #2

LHSP #3

LHSP #4

LHSP #5

Middle Tulare clay

Amnicola clay

Base of Tulare Formation

Figure 3. Vertical flow gradient at Lost Hills multiple-well 

monitoring well site (LHSP), Kern County, California.
upper part of the Tulare aquifer system 

is more strongly affected by groundwater 

pumping than is the middle part. The 

smaller declines and lack of recovery of 

water levels through the period of record 

for well LHSP #2 indicated that the layer 

in the lower part of the Tulare aquifer 

system could have a delayed response to 

groundwater pumping in overlying layers. 

The monotonic increases in LHSP #5, 

above the Corcoran Clay equivalent, 

indicated that this shallow aquifer layer 

is not affected by groundwater pumping 

and could have limited hydraulic 

connection to aquifer layers below the 

Corcoran Clay equivalent. The pattern of 

increased water levels observed in well 

LHSP #1 and short-term fluctuations 

over time differed from the observations 

of wells LHSP #2–5, indicating that 

water levels at the bottom of the Tulare 

aquifer system are responding to 

different hydrologic stresses than the 

overlying layers. These stresses may 

include upgradient oil-field activities 

(injection, steam or water flooding, or 

pumping) to the southwest. The shortterm fluctuations of 1⁄2 to 1 foot in water 

level could be indicative of upgradient 

pumping or injection activity or that the 

well is in a relatively low permeability 

layer that is highly responsive to changes 

in aquifer conditions. The approximate 

3-foot drop and subsequent recovery 

in water level observed in LHSP #1 

in late November 2018 was a result of 

drawdown and recovery associated with 

pumping of this well for water-quality 

sampling. Further analysis of water levels 

over time in comparison with oil-field 

activities, such as pumping and injection, 

are needed to help determine the 

hydrologic stresses affecting water levels 

at the base of the Tulare aquifer system.

Geochemistry

To delineate the chemical 

characteristics and source of the 

groundwater, samples were collected 

from each well in accordance with the 

protocols established by the USGS 

National Field Manual (U.S. Geological 

Survey, variously dated) and analyzed 

for major-ion chemistry; minor and trace 

elements; nutrients; radium isotopes; 

dissolved organic carbon and organic 

carbon characteristics; volatile organic 

compounds; low molecular weight 

organic acids; concentrations and isotopic 

values of light hydrocarbon gases; the 

stable isotopes of hydrogen (deuterium) 

and oxygen (oxygen-18) in water; boron, 

strontium, and lithium isotopes; carbon 

(carbon-13) in dissolved inorganic carbon 

and carbon-14 activities; noble and 

atmospheric gases; and groundwater-age 

tracers tritium and sulfur hexafluoride. 

The collection and analysis procedures 

are further described by Dillon and 

others (2016), Davis and others 

(2018b), and Wright and others (2019). 

Sampling began in November 2018, 

6 months after well development was 

completed, and was done in February 

2019. Results for many analytes were 

not available at the time this report was 

prepared (April 2019). Consequently, 

results of water-quality samples are 

not discussed in this report other than 

the distribution of total dissolved 

solids (TDS). 

Most of the aquifer system to the 

base of the Tulare Formation had TDS 

of less than 10,000 mg/L. The water 

samples from the LHSP wells had 

total dissolved solids concentrations 

ranging from 3,400 (LHSP #3) to 

13,200 (LHSP #5) mg/L residue on 

evaporation at 180 degrees Celsius 

(table 4). Total dissolved solids were 

calculated at multiple depths from the 

geophysical logs using the algorithm 

developed by Bateman and Konen 

(1977; fig. 5), and the TDS data are 

available from Gillespie and others 

(2019a). Total dissolved solids measured 

from groundwater samples collected from 

the wells confirmed that the calculated 

estimates from the geophysical logs 

are reasonable. Total dissolved solids 

calculations at selected depths shown on 

figure 5 indicate that TDS values were 

higher near the surface and at depth, 

exceeding 10,000 mg/L in some zones 

above 410 ft and below 1,680 ft bls, and 

the lowest TDS values were between 

3,000 and 5,000 mg/L in zones between 

500 and 900 ft bls.

Accessing Data

The data presented in this report 

can be accessed using the USGS 

National Water Information System 

(NWIS) web page (NWISWeb) at 

https://waterdata.usgs.gov/nwis/. All 

discrete water-level measurements 

and the daily maximum, minimum, 

and median values for all time-series 

water-level data for sites presented in 

this report are available through the 

USGS NWISWeb. In digital copies 

of this report, the site identification 

numbers (table 1) presented in the tables 

are hyperlinked directly to the data on 

NWISWeb. Any updates applied to data 

presented in this report after publication 

will be available on NWISWeb.

2018

May

7 14 21 28 7 14 21 28 7 14 21 28 7 14 21 28 7 14 21 28 7 14 21 28 7 14 21 28 7 14 21 28 7 14 21 28 7 14 21 28

June July Aug. Sept. Oct. Nov. Dec. Jan. Feb.

–12

–10

–8

–6

–4

–2

0

2

4

6

8

10

12

2019

Drawdown from pumping of LHSP #1

Change in water level relative to May 31, 2018, at 3:00 p.m. Pacific daylight time

 Change in water level (feet) relative to May 31, 2018, 

at 3:00 p.m. Pacific daylight time

LHSP #1

LHSP #2

LHSP #3

LHSP #4

LHSP #5

Increase in water level Decrease in water level

EXPLANATION

LHSP #5, 210’–230’

LHSP #4, 490’–510’

LHSP #3, 700’–720’

LHSP #2, 1,110’–1,130’

LHSP #1, 1,780’–1,800’

Figure 4. Change in water level relative to May 31, 2018, observed in wells at the Lost Hills 

multiple-well monitoring well site (LHSP), Kern County, California.
Geophysical logs can be accessed 

through the USGS GeoLog Locator 

portal (https://webapps.usgs.gov/

GeoLogLocator). Sites with available 

geophysical logs can be searched by the 

USGS site identification number (table 1) 

or can be located using the interactive 

map. Lithologic samples, shaker and 

sieve, collected during the drilling of the 

multiple-completion monitoring wells 

are archived at the USGS office in San 

Diego, California. Photos of the 

shaker and sieve samples (along 

with the full descriptions and notes 

recorded by the site hydrologist) 

can be accessed through the USGS 

GeoLog Locator. Formal requests 

for access to samples, field notes, 

or bench notes can be directed 

to the U.S. Geological Survey 

California Water Science Center.

By Rhett R. Everett, Adam Kjos, Anthony A. Brown, Janice M. Gillespie, 

and Peter B. McMahon

Table 4. Water-quality indicators (field parameters) and total dissolved solids in 

samples collected from Lost Hills multiple-well monitoring site (LHSP), Kern County, 

California.

[Wells ordered from shallowest to deepest. The five-digit U.S. Geological Survey (USGS) parameter 

code below the constituent name is used to uniquely identify a specific constituent or property. 

Threshold type: SMCL-CA, California Department of Public Health secondary maximum contaminant 

level; SMCL-US, U.S. Environmental Protection Agency secondary maximum contaminant level. 

Abbreviations: mg/L, milligrams per liter; °C, degrees Celsius; μS/cm, microsiemens per centimeter; 

CaCO3, calcium carbonate; na, not available; <, less than; >, greater than; *, value above threshold 

level] 

Common 

well name

Dissolved 

oxygen, field

(mg/L)

(00300)

pH, field 

(standard units)

(00400)

Water 

temperature, field

(°C)

(00010)

Threshold type na SMCL-US na

Threshold level na <6.5–8.5> na

LHSP #5 0.058 7.2 23.6

LHSP #4 0.071 7.3 25.7

LHSP #3 0.139 7.6 25.5

LHSP #2 0.070 7.1 25.8

LHSP #1 0.137 6.6 24.7

Common 

well name

Specific 

conductance, field 

(μS/cm at 25 °C) 

(00095)

Alkalinity, lab 

(mg/L as CaCO3) 

(29801)

Total 

dissolved solids 

(mg/L) 

(70300)

Threshold type SMCL-CA na SMCL-US

Threshold level 1900 (1,600) na 500

LHSP #5 *17,200 158 *13,200

LHSP #4 *5,940 187 *4,050

LHSP #3 *5,380 474 *3,400

LHSP #2 *10,400 180 *6,180

LHSP #1 *22,800 535 *13,800

1

The SMCL-CA for specific conductance has recommended lower and upper threshold values. The 

upper value is shown in parentheses.

Figure 5. Measured and calculated total dissolved 

solids (TDS) for selected depths at Lost Hills 

multiple-well monitoring well site (LHSP), Kern 

County, California. Calculations based on the Bateman 

and Konen Equation (1977).

0

100

200

300

400

500

600

700

800

900

1,000

1,100

1,200

1,300

1,400

1,500

1,600

1,700

1,800

1,900

Depth, in feet below land surface

Calculated TDS

Measured TDS

EXPLANATION

Polynomial trendline

of calculated TDS

Measured and calculated 

total dissolved solids (TDS)

0 5,000 10,000 15,000 20,000

Total dissolved solids, in milligrams per liter

3,000 TDS 10,000 TDS
References Cited

Bateman, R.M., and Konen, C.E., 1977, The log analyst and the programmable pocket calculator: Society of Petrophysicists and Well Log 

Analysts, v. 18, no. 5, p. 3–10.

California Department of Conservation, 2018, Oil and gas online data: Division of Oil, Gas, and Geothermal Resources, accessed 

February 20, 2018, at https://www.conservation.ca.gov/dog/Online_Data/Pages/Index.aspx. California Department of Water Resources, 2015, California’s groundwater update 2013—A compilation of enhanced content for 

California water plan: California Department of Water Resources, accessed November, 26, 2018, at https://water.ca.gov/-/media/DWRWebsite/Web-Pages/Programs/California-Water-Plan/Docs/Update2013/GroundwaterUpdate/Californias-Groundwater-Update-2013--

Tulare-Lake-Regional-Report.pdf. California Department of Water Resources, 2016, Bulletin 118 interim update 2016: California Department of Water Resources, accessed 

September 26, 2018, at https://water.ca.gov/Programs/Groundwater-Management/Bulletin-118. Croft, M.G., 1972, Subsurface geology of the late Tertiary and Quaternary water-bearing deposits of the southern part of the San Joaquin 

Valley, California: U.S. Geological Survey Water Supply Paper 1999–H, 29 p., https://doi.org/10.3133/wsp1999H. Cunningham, W.L., and Schalk, C.W., comps., 2011, Groundwater technical procedures of the U.S. Geological Survey: U.S. Geological 

Survey Techniques and Methods 1–A1, 151 p., https://doi.org/10.3133/tm1A1. Davis, T.A., Landon, M.K., and Bennett, G.L., 2018a, Prioritization of oil and gas fields for regional groundwater monitoring based on 

a preliminary assessment of petroleum resource development and proximity to California’s groundwater resources: U.S. Geological 

Survey Scientific Investigations Report 2018–5065, 115 p., https://doi.org/10.3133/sir20185065. Davis, T.A., Teunis, J.A., McCarlson, A.J., Seitz, N.O., and Johnson, J.C., 2018b, Water chemistry data for samples collected at 

groundwater and surface-water sites near the Lost Hills and Belridge oil fields, November 2016–September 2017, Kern County, 

California: U.S. Geological Survey data release, https://doi.org/10.5066/F7NS0T5M. Dillon, D.B., Davis, T.A., Landon, M.K., Land, M.T., Wright, M.T., and Kulongoski, J.T., 2016, Data from exploratory sampling of 

groundwater in selected oil and gas areas of coastal Los Angeles County and Kern and Kings Counties in southern San Joaquin Valley, 

2014–15—California oil, gas, and groundwater project (ver. 1.1, October 2017): U.S. Geological Survey Open-File Report 2016–1181, 

24 p., https://doi.org/10.3133/ofr20161181. Duffield, G.M., 2007, AQTESOLV for Windows version 4.5 user’s guide: Reston, Va., HydroSOLVE, Inc., 529 p., 

https://hwbdocuments.env.nm.gov/Los%20Alamos%20National%20Labs/General/37764.pdf. Everett, R.R., Gibbs, D.R., Hanson, R.T., Sweetkind, D.S., Brandt, J.T., Falk, S.E., and Harich, C.R., 2013, Geology, water-quality, 

hydrology, and geomechanics of the Cuyama Valley groundwater basin, California, 2008–12: U.S. Geological Survey Scientific 

Investigations Report 2013–5108, 62 p., https://doi.org/10.3133/sir20135108. Everett, R.R, Ledbetter, B.J., and Rodriguez, O., 2020, Aquifer test data for multiple-well monitoring site (LHSP), Kern County, 

California: U.S. Geological Survey data release, https://doi.org/10.5066/P9LGXIN8. Faunt, C.C., ed., 2009, Groundwater availability of the Central Valley aquifer, California: U.S. Geological Survey Professional Paper 1766, 

225 p., https://doi.org/10.3133/pp1766. Frink, J.W., and Kues, H.A., 1954, Corcoran Clay—A Pleistocene lacustrine deposit in San Joaquin Valley, California: 

American Association of Petroleum Geologists, v. 38, no. 11, p. 2357–2371, https://doi.org/10.1306/5CEAE0A0-16BB-11D7-

8645000102C1865D. Gillespie, J.M., Davis, T.A., Ball, L.B., Herrera, P.J., Wolpe, Z., Medrano, V., Bobbitt, M., and Stephens, M.J., 2019a, Geological, 

geochemical, and geophysical data from the Lost Hills and Belridge oil fields: U.S. Geological Survey data release, 

https://doi.org/10.5066/P90QH6CI. Gillespie, J.M., Davis, T.A., Stephens, M.J., Ball, L.B., and Landon, M.K., 2019b, Groundwater salinity and the effects of produced 

water disposal in the Lost Hills–Belridge oil fields, Kern County, California: Environmental Geoscience, v. 26, no. 3, p. 73–96, 

http://archives.datapages.com/data/deg/2019/EG032019/eg18009/eg18009.htm. Greene, E.A., and Shapiro, A.M., 1995, Methods of conducting air-pressurized slug tests and computation of type curves for estimating 

transmissivity and storativity: U.S. Geological Survey Open-File Report 95–424, 43 p., https://doi.org/10.3133/ofr95424. Heath, R.C., 1983, Basic ground-water hydrology: U.S. Geological Survey Water Supply Paper 2220, 86 p., https://doi.org/10.3133/

wsp2220. Hyder, Z., Butler, J.J., Jr., McElwee, C.D., and Liu, W., 1994, Slug tests in partially penetrating wells: Water Resources Research, v. 30, 

no. 11, p. 2945–2957, https://doi.org/10.1029/94WR01670. Kenyon, B., Kleinberg, R., Straley, C., Gubelin, G., and Morriss, C., 1995, Nuclear magnetic resonance imaging—Technology for the 

21st Century: Oilfield Review, v. 7, no. 3, p. 19–33.

Keys, W.S., 1990, Borehole geophysics applied to ground-water investigations: U.S. Geological Survey Techniques of Water-Resources 

Investigations, book 2, chap. E2, 150 p., https://doi.org/10.3133/twri02E2. Keys, W.S., and MacCary, L.M., 1971, Application of borehole geophysics to water-resources investigations: U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 2, chap. E1, 126 p., https://doi.org/10.3133/twri02E1. Leap, D.I., 1984, A simple pneumatic device and technique for performing rising water level slug tests: Ground Water Monitoring and 

Remediation, v. 4, no. 4, p. 141–146, https://doi.org/10.1111/j.1745-6592.1984.tb00905.x. Page, R.W., 1983, Geology of the Tulare Formation and other continental deposits, Kettleman City area, San Joaquin Valley, California, 

with a section on ground-water management considerations and use of texture maps: U.S. Geological Survey Water-Resources 

Investigations Report 83–4000, 28 p., https://doi.org/10.3133/wri834000. Shuter, E., and Teasdale, W.E., 1989, Application of drilling, coring, and sampling techniques to test holes and wells: U.S. Geological 

Survey Techniques of Water-Resources Investigations, book 2, chap. F1, 97 p., https://doi.org/10.3133/twri02F1. U.S. Geological Survey, variously dated, National field manual for the collection of water‐quality data: U.S. Geological Survey Techniques 

of Water-Resources Investigations, book 9, chaps. A1–A9, 2 v. [variously paged], 

https://water.usgs.gov/owq/FieldManual/. U.S. Geological Survey, 2019, California oil, gas, and groundwater (COGG) 

program: accessed July 8, 2019, at https://ca.water.usgs.gov/projects/oil-gasgroundwater/index.html. Wood, P.R., and Davis, G.H., 1959, Ground-water conditions in the Avenal–

McKittrick area, Kings and Kern Counties, California: U.S. Geological Survey 

Water-Supply Paper 1457, 141 p., https://doi.org/10.3133/wsp1457. Woodring, W.P., Stewart, R., and Richards, R.W., 1940, Geology of the 

Kettleman Hills oil field, California—Stratigraphy, paleontology, and structure: 

U.S. Geological Survey Professional Paper 195, 170 p., https://doi.org/10.3133/

pp195. Wright, M.T., McMahon, P.B., Landon, M.K., and Kulongoski, J.T., 2019, 

Groundwater quality of a public supply aquifer in proximity to oil development, 

Fruitvale oil field, Bakersfield, California: Applied Geochemistry, v. 106, 

p. 82–95, https://doi.org/10.1016/j.apgeochem.2019.05.003.

For more information concerning the research in this 

report, contact the

 Director, California Water Science Center

U.S. Geological Survey

6000 J Street, Placer Hall

Sacramento, California 95819

https://ca.water.usgs.gov

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