24N

1 (6

)

24P3

(5)

24P2

(1)

24P1

(2)

25H1

(4)

25J1

(3)

25R2

25R1

3,400

3,200

3,000

2,800

2,600

2,400

2,200

2,000

?

?

FAUL

T

FAUL

T

?

?

A A'NW SE

24N1

(6)

24P3

(5)

24P2

(1)

24P1

(2)

25H1

(4)

25J1

(3)

25R2

25R1

3,400

3,200

3,000

2,800

2,600

2,400

2,200

2,000

?

?

FAUL

T

FAUL

T

A A'

Vertical Scale - 1/2 in = 200 ft

NW SE

Vertical Exaggeration 4X

Right: Cross section A - A' showing the perforated intervals of each well used in the study. Also shown are the altitudes of the water table and the locations of known faults.

MILLARDCANYON

BANNING

CABAZON

Vertical Scale - 1/2 in = 200 ftVertical Exaggeration 4X

Alti

tude

, in

feet

abo

ve s

ea le

vel

Alti

tude

, in

feet

abo

ve s

ea le

vel

Gandy Ranch Fault

South Branch of

Potrero Canyon

LandSat 7 image processed by M.J. Rymer

Image taken from: USGS Cabazon Digital Orthoquadrangle, Western Map Agency, 1996

A

A'

Note: Wells 24N1, 25H1 and 25J1 were projected to the cross section. Well construction and lithology information is

presented as reported in drillers' reports and is generalized for presentation purposes.

5)

25

Cluster ACluster A

Cluster BCluster B

Cluster CCluster C

?

EXPLANATION

Production Well Unused Well Irrigation Well, Unused

T2S

Gravel

Sand

ClayDecomposed Granite

Gravel with Clay

Silt and Sand

0 1/4 1/2Miles

EXPLANATION:

No Data

Water Table

Perforated Interval

EXPLANATION:

No Data

0 1/4 1/2Miles

Water Table

Morongo Indian Reservation Boundary

Wells in Potrero Canyon are the main source of water for the Morongo Band of Mission Indians, located near Banning, California. A series of pumping tests were completed on four water-supply wells in the Canyon during February 27 to March 2, 2001. The purpose of the tests was to determine the productivity of each well and the interference (drawdown or water-level decline) each pumped well produced in surrounding wells.

During each pumping test, a well was pumped at a fairly constant rate for several hours and drawdown was measured in the pumping well; nearby production wells (mostly idle) were used as observation wells. Productivity of the pumping well, specific capacity in gallons per minute per foot of drawdown (gal/min/ft), was determined from time-drawdown data in the pumping well. The range of specific capacities from these tests were 29.9 gal/min/ft, measured in well 24P3 (2S/1E-24P3) to 12.8 gal/min/ft in well 25H1. A specific capacity of 34.4 gal/min/ft was reported (Constant Flow Test notes by McCalla Bros.) for well 24N1. The amount of the drawdown in the observation wells during each pumping test was used to determine the interference between wells.

In this report, wells are arranged as clusters A, B, and C based on well proximity and similarity of water-level eleva-tions (see Potrero Canyon map in "Methods"). For tests per-formed in Potrero Canyon, wells 3, 4, 5 and 6 were used as pumping wells and wells 1, 2, 3, 4, 5 and 25R2 were used as observation wells. Wells 6 (24N1) and 25R1 (location shown only in "Methods") could not be measured due to obstructions in the wells.

Time-drawdown data were collected using 10 and 50 psig (pounds per square inch, gauged) pressure transducers and da-taloggers. Transducers were set at a depth of about 25 feet be-low static water level in observation wells and approximately 80 ft below static water level in pumping wells. The transduc-ers were calibrated prior to use and had an accuracy of ± 0.03 ft for the 10 psig and ± 0.3 ft for the 50 psig transducers. Ap-proximately 14 hours of background data were collected for wells 1, 2, and 5 prior to start of the first test.

Water-level measurements were made manually using a calibrated electric measuring tape to verify the accuracy of transducer readings. Each well was manually measured be-fore initial testing and approximately every hour throughout the duration of each test. On average, each well was pumped for approximately 8 hours and was allowed to recover overnight for about 15 hours before pumping tests of other wells. No manual water-level measurements were made during the recovery period. During the pumping test at well 3, well 6 was pumped intermittently to meet water supply demands.

Regional map of study area showing the Morongo Indian Reservation boundary (light shade) and surrounding areas. The location of Potrero Canyon is highlighted (see map below) and is located approximately 90 miles east of Los Angeles, near the towns of Banning and Cabazon.

METHODS

Sacramento

Redding

Bakersfield

San Francisco

Los Angeles

San Diego

Salton Sea

Ukiah

200 MILES0200 KILOMETERS0

CALIFORNIA

References:

Map of Potrero Canyon showing the locations of selected wells within the study area and line of cross section A-A'. Also shown are the locations of known faults within the area (Dibblee, 1982), dashed where approximately located.

Pumping test results showed that wells 5 and 6 within Cluster A have the highest specific ca-pacities and the lowest interference between wells within the same cluster. Wells in Cluster A had an average specific capacity of 32 gallons per minute per foot [(gal/min)/ft] of drawdown and a maximum interference of 6.4 ft in surrounding wells. Wells within Cluster B, had an average specific capacity of 14 gallons per minute per foot [(gal/min)/ft] of drawdown, about one half of the value for wells in Cluster A, and a maximum interference value of 37.3 ft in nearby wells, more than double the value for wells in Cluster A. Note that the highest inter-ference is observed between wells 3 and 4 in Cluster B, even though they are farther apart (about 75 ft more) than wells 5 and 6 in Cluster A. Therefore, concurrent pumping of wells 5 and 6 within Cluster A would produce a higher yield and less drawdown than pumping wells 3 and 4 within Cluster B. No specific capacity values were calculated for Cluster C wells; well 25R1 was not used for pumping or observation and well 25R2 was used only for observation. Water levels observed during all pumping tests showed that pumping a well in one cluster re-sulted in no drawdown in wells in other clusters. These results suggest that the hydraulic in-teraction between Clusters A, B, and C is limited. Boundaries, such as faults or buried out-crops, could significantly limit ground-water flow and the hydraulic response between wells on opposite sides of such boundaries. Further studies would be needed to determine the type and location of potential boundaries located in Potrero Canyon.

116˚50'116˚50'40"

Acknowledgments: The authors thank the Morongo Band of Mission Indians for their cooperation in this study and Joan Blainey of the U. S. Geological Survey, Sacramento, California for providing additional field help.

Dibblee, T. W., 1982, Geologic map of the Banning (15-minute) quadrangle, California VTN Consolidated, Inc. 1975, Multiple Purpose Water Resources Investigation, Morongo Indian Reservation, California

33˚58'40"

N

34˚00'

33˚55'

116˚55' 116˚45'

0

0 0.5 KILOMETERS

0.5 MILES

Pumping Test Results for Wells Within Potrero Canyon, Morongo Band of Mission Indians Reservation, California

Prepared in cooperation with the MORONGO BAND OF MISSION INDIANS

General Lithology

Generalized Well Construction

INTRODUCTION

Pimentel, M. Isabel and Christensen, Allen H.,Pumping Test Results for Wells Within Potrero Canyon, Morongo Band of Mission Indians Reservation, California, 2002

OPEN-FILE REPORT 02-228U.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY

by M. Isabel Pimentel and Allen H. Christensen, 2002

SUMMARY OF RESULTS

LITHOLOGY / WELL CONSTRUCTION

T4S

R1ER1W R2E

T2S

T3S

R3E

Left: Cross section A - A' showing general lithology of selected wells in the study area. Also shown are the altitudes of the water table and known fault locations.

Cluster A

Cluster B

Cluster C

Cluster A

Cluster B

Cluster C

0 5 MILES

0 5 KILOMETERS?

R1E R2E

10 10

StudyArea

Note Change in Scale

Note Change in Scale

116˚50'40" 116˚49'30"

33˚58'40"

R1E R2E

T2S

0

0 1 KILOMETER

1 MILE

PUMPING TEST AT WELL 4

Date of Test - March 2, 2001

Max Drawdown Specific CapacityWell Status (in ft) (gal/min/ft of drawdown) 1 Observation 0.1 -- 2 Observation 0.2 -- 3 Observation 37.3 -- 4 Pumping 187.4 12.8 5 Observation NM -- 6 Observation NM --25R2 Observation 0.0 --

Average Pumping Rate (in GPM): 2,400Duration of pumping (in hours): 8.2

200

160

120

80

40

0

Resting Phase(15 hours)

Pumping Phase

Pump on

Resting Phase(15 hours)

Pumping Phase

Time Since Pumping Started, in Hours0 1 2 3 4 5 6 7

0

5

10

15

20

25

30

35

40

Dra

wdo

wn,

in fe

et

25H1 (WELL 4)Pumping Well

Dra

wdo

wn,

in fe

et

24P3 (Well 5)-NM24P2 (Well 1)24P1 (Well 2)

25R225J1 (Well 3)

Cluster A

Cluster B

Cluster C

FaultsPumping well

Observation well

Pumping Well: 25H1 (Well 4)

Observation Wells

24P2 (1)24P2 (1)24P1 (2)24P1 (2)

25J1 (3)25J1 (3)

25H1 (4)25H1 (4)

25R225R2

116˚50'40" 116˚49'30"

33˚58'40"

R1E R2E

T2S

PUMPING TEST AT WELL 3

0

0 1 KILOMETER

1 MILE

Date of Test - March 1, 2001

0 1 2 3 4 5 6

Time Since Pumping Started, in Hours

Max Drawdown Specific CapacityWell Status (in ft) (gal/min/ft of drawdown) 1 Observation 1.0* -- 2 Observation 0.28* -- 3 Pumping 36.4 15.1 4 Observation 13.9 -- 5 Observation NM -- 6 Observation NM --25R2 Observation 0.0 --

Average Pumping Rate (in GPM): 550Duration of pumping (in hours): 6.5* Response due to intermittent pumping of well 6.

Dra

wdo

wn,

in fe

et

Pumping Phase

25J1 (WELL 3)Pumping Well

Dra

wdo

wn,

in fe

et

Pumping Phase

Pump on

24P3 (Well 5) - NM

24P2 (Well 1) 24P1 (Well 2)

25H1 (Well 4) 25R2

40

30

20

10

0

50

60

70

RestingPhase

(17 hours)

RestingPhase

(15 hours)

10

12

14

0

2

4

6

8

16

FaultsPumping well

Observation well

Observation Wells

(5)

Cluster A

Cluster B

Cluster C

24P1 (2)24P1 (2)

25R225R2

25H1 (4)25H1 (4)

25J1 (3)25J1 (3)

Pumping Well: 25J1 (Well 3)

24P2 (1)24P2 (1)

116˚50'40" 116˚49'30"

33˚58'40"

R1E R2E

T2S

PUMPING TEST AT WELL 5

Date of Test - February 28, 2001

Max Drawdown Specific CapacityWell Status (in ft) (gal/min/ft of drawdown) 1 Observation 6.4 -- 2 Observation 0.5 -- 3 Observation NM -- 4 Observation 0.05 -- 5 Pumping 60.2 29.9 6 Observation NM -- 25R2 Observation 0.0 --

0

0 1 KILOMETER

1 MILE

24P3 (WELL 5)Pumping Well

70

60

50

40

30

20

10

0

Dra

wdo

wn,

in f

eet

Pump on

RestingPhase

(15 hours)

Time Since Pumping Started, in Hours

Pumping Phase

Dra

wdo

wn,

in fe

et

Average Pumping Rate (in GPM): 1,800Duration of pumping (in hours): 7.5

Pumping Phase

0 1 2 3 4 5 6 7

24P2 (Well 1) 24P1 (Well 2)

25H1 (Well 4) 25R225J1 (Well 3) - NM

RestingPhase

(15 hours)

10

12

14

0

2

4

6

8

16

Observation Wells

Cluster A

Cluster B

Cluster C

Faults

25R225R2

Pumping Well: 24P3 (Well 5)

24P3 (5)24P3 (5)

24P1 (2)24P1 (2)24P2 (1)24P2 (1)

25H1 (4)25H1 (4)

Pumping well

Observation well

33˚58'40"

R1E R2E

T2S

PUMPING TEST AT WELL 6◊

Max Drawdown Specific CapacityWell Status (in ft) (gal/min/ft of drawdown) 1 Observation 1.3 -- 2 Observation 0.07 -- 3 Observation NM -- 4 Observation 0.08 -- 5 Observation 2.3 -- 6 Pumping NM 34.4h25R2 Observation NM --

0

0 1 KILOMETER

1 MILE

116˚50'40" 116˚49'30"

Time Since Pumping Started, in Hours

Date of Test - February 27, 2001

Dra

wdo

wn,

in fe

et

EXPLANATION OF TERMS:

NM Not MeasuredGPM Gallons Per Minute34.4h Historical value. April 1997 Constant Flow Test conducted by McCalla Bros. Pump and Drilling Inc. at a rate of 2,500 GPM.

Note: no data collected for Wells 6, 3, and 25R2Average Pumping Rate (in GPM): 2,400Duration of pumping (in hours): 7.7

24P3 (Well 5) 24P2 (Well 1) 24P1 (Well 2)

25H1 (Well 4) 25R2 - NM

0 1 2 3 4 5 6 7

Pump on

Pumping Phase

10

12

14

0

2

4

6

8

16

Time Since Pumping Started, in Hours

RestingPhase

(16 hours)

25J1 (Well 3) - NM

Observation Wells

25J1 (3)

Cluster A

Cluster B

Cluster C25R225R2

24P1 (2)24P1 (2)

24P3 (5)24P3 (5)24P2 (1)24P2 (1)

25H1 (4)25H1 (4)

FaultsPumping well

Observation well

Pumping Well: 24N1 (Well 6)

◊ Pumping tests shown in order from North to South (6, 5, 4, and 3)