Water-Supply and Irrigation Paper No. 112 Series 0, Underground Waters, 30

DEPARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY

CHARLES D. WALCOTT, DIRECTOR

UNDERFLOW TESTS

IN THE

DRAINAGE BASIN OF LOS ANGELES RIYER

BY

HOMER

WASHINGTON

GOVERNMENT PRINTING OFFICE

1905
CONTENTS.

Page.

Letter of transmittal...................................................... 7

Introduction............................................................. 9

Ground water............................................................ 9

Water table.......................................^...................... 10

Fluctuations of water table................................................. 10

Velocity of underflow -...-....--..............---.-.---..---...-.---..-.. 10

Methods and apparatus used in underflow tests........-..--......---.---.-. 11

Location of test wells................................................. 11

Hand driving........................................................ 12

Well-drilling rig ..................................................... 13

Machine drilling ..................................................... 13

Apparatus ........................................................... 14

Engine ................................................i......... 14

Pump ............................................................ 15

Light drivepipe .--...........-....-..-..--.-.-...-...:....---.... 15

Heavy drivepipe --.-.-.-......--.....-.-.-.-.......--.....-...-.. 15

Shoe ............................................................ 16

Drive head _._.................._.__..........._...._.........-.. 16

Buffer block..................................................... 17

Hammer ........................................................ 17

Wash rods....................................................... 18

Chopping bit .................................................... 18

Water swivel ..-..........-..-.-.....---.---......----...-...-... 19

Derrick.......................................................... 19

Blocks........................................................... 19

Well points...................................................... 20

Jackscrews ...................................................... 20

Placing well points for underflow tests................................. 21

Testing apparatus .................................................... 21

Wire............................................................ 21

Electrodes....................................................... 21

Switch clock..................................................... 22

Recording ampere meter...........................-..-.---.-...-. 23

Battery...........................J..^,.......................... 23

Method of measuring the velocity of underflow..-.-......-.....---..... 24

Pumping ........................ ................................ 24

Wiring.......................................................... 25

Charging well A.................................................. 26

Determining velocity of underflow ................................ 27

Computations of discharge................................................ 29

Basin of Los Angeles River ............................................... 32

Tests in 1902............................................................. 34

Stations and results .............................................. 34

Tests at Huron street in 1903.............................................. 39

Stations and results .............................................. 42

Discharge at Huron street .._..-.........-........-.-..-......-... 51

Cost of tests at Huron street...................................... 52

Nummary................................................................ 53

Index ................................................................... 55
ILLUSTRATIONS.

Pase-

?-JATE I. A, Well points; B, Driving well points.............-.--.---...... 12

II. A, Well-drilling rig; S, Well-drilling machinery.................. 14

III. A, Rotator and driving machinery; B, Jackscrews ................ 16

IV. Electrodes and well............................................. 20

V. Switch clock ................................................... 22

VI. A and B, Charts used with recording ampere meter............... 24

VII. A, Recording ampere meter; B, Battery.......................... 26

T"G. 1. Heavy drivepipe....--..------..----.....-..-.-..------.....-....- 16

2. Drive shoe ....................................................... 16

3. Drive head...................................................... 17

4. Bjuffer block...................................................... 17

5. Hammer......................................................... 18

6. Chopping bit..................................................... 18

7. Water swivel..................................................... 19

8. Electrodes........................................................ 22

9. Plan of test wells and apparatus...............................< .... 24

10. Plan of test wells and apparatus.................................... 25

11. Ampere curves ................................................... 28

12. Drainage basin of Los Angeles River ............................... 33

13. Underflow tests at station 1........................................ 34

14. Underflow tests at station 2........................................ 35

15. Underflow tests at station 3........................................ 36

16. Underflow tests at station 4........................................ 37

17. Underflow tests at station 5........................................ 38

18. Underflow tests at station 6........................................ 39

19. Underflow tests at station 7...-......--.-.--..........--........... 40

20. Underflow tests at station 8........................................ 41

21. Map of Huron street and vicinity .................................. 42

22. Huron street cross section ......................................... 42

23. Underflow tests at station 9........................................ 43

24. Underflow tests at station 10....................................'... 44

25. Underflow tests at station 11....................................... 45

26. Underflow tests at station 12....................................... 46

27. Underflow tests at station 13....................................... 47

28. Underflow tests at station 14.....................................\. 48

29. Underflow tests at station 15....................................... 49

30. Underflow tests at station 16 ...................................... 50
LETTER OF TRANSMITTAL.

DEPARTMENT OF THE INTERIOR, 

UNITED STATES GEOLOGICAL SURVEY,

RECLAMATION SERVICE, 

Washington, D. C., March 28, 1904.

SIR: I have the honor to transmit, for publication in the series of 

Water-Supply and Irrigation Papers, a manuscript entitled " Underflow Tests in the Drainage Basin of Los Angeles River," by Mr. 

Homer Hamlin.

The report describes the conditions under which ground water 

usually occurs in arid regions and the fluctuations in the water level 

due to rainfall and other causes. The methods used in obtaining this 

information are of interest, and the paper will contribute valuable 

material to the important subject of underground waters and their use 

in the arid regions.

Very respectfully, F. H. NEWELL,

Chief Engineer. 

Hon. CHARLES D. WALCOTT,

Director United States Geological Survey.

7 

IKK 112 05 2
UNDERFLOW TESTS IN THE DRAINAGE BASIN OF LOS

ANGELES RIVER.

By HOMER HAMLIN.

INTRODUCTION.

The purpose of this report is to assemble in one publication the 

results of a series of underflow tests made in the drainage basin of 

Los Angeles River in 1902 and 1903 by the United States Geological 

Survey.

This report briefly describes the conditions under which ground 

water usually occurs, especially in arid regions, and the fluctuations in 

its water level due to rainfall and to sinking flood waters.

The method of testing used was invented by Prof. Charles S. Slichter, and is fully described in "The Motions of Underground Waters." a 

Up to the present few investigators have used this method.

An attempt has been made to describe briefly the method of sinking 

test wells and the machinery designed and used during this investigation. The various devices used in testing and the arrangement of the 

instruments, the methods of testing found most satisfactory, the 

results obtained at each of the testing stations, and the amount of 

underflow supposed to pass the Huron street section, are fully 

described.

GROUND WATER.

By ground water is meant water percolating beneath the surface of 

the earth. The original source of all ground water is rainfall. Part 

of the rain soaks into the ground and percolates downward until it 

reaches a level where the interstices of the rocks, sand, and gravel are 

already saturated; another part is absorbed by growing plants or 

evaporated from the surface of the ground; and still another part 

runs off in surface streams.

aSlichter, Charles S., The motions of underground waters: Water-Sup, and Irr. Paper No. 67, U. S. 

Geol. Survey, 1902.

9
10 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

WATER TABLE.

The upper surface of the water-soaked zone in pervious ground is 

called the water table or water plane. From the surface of the 

ground to the water table the ground is damp but not saturated, and 

all contributions of surface water continually tend to sink downward, 

while below this level the ground is completely saturated; that is, all 

of the open spaces between the rock particles are full of water. The 

water table is the level at which water is struck in a well. In artesian 

belts the water is under pressure, being confined by overlying impervious strata, and when such strata are pierced it rises to the level of 

the outcrop of the water-bearing formation. The water table is not 

a level plane like the surface of a lake, except rarely in inclosed 

basins, but usually has a slope toward the main drainage lines of the 

region, to which the ground water slowly flows. The slopes usually 

follow in a general way the surface topography, but are much flatter.

FLUCTUATIONS OF WATER TABLE.

As the ground below the water table is completely saturated, any 

contributions of water from the surface must result either in raising the 

water table or in a lateral movement of the ground water toward some 

outlet. Usually both phenomena occur, the lateral flow being a result 

of and following the rise in the water table. In humid regions the 

supply from rainfall is so nearly constant throughout the seasons that 

the position of the water table is practically fixed, and the rate of 

lateral movement does not change appreciably from year to year. In 

arid regions much of the ground water under the plains and valleys is 

supplied by the streams which pour down from adjacent mountain 

ranges. When such streams leave the mountain canyons they soon 

sink in their debris cones of sand, gravel, and bowlders; in such localities the water table is sometimes 200 or 300 feet below the surface. 

When in flood such streams discharge enormous quantities of water, 

which sinks and is added to the ground water of the region. The 

immediate result is the raising of the water table, often 25 to 50 feet, 

over the region where the sinking occurs. The ground water afterwards flows outward in a generally horizontal direction from these 

regions and the water table is gradually lowered. In arid regions the 

water table rises sometimes many feet during rainy seasons and gradually sinks in dry years or during the dry season.

VELOCITY OF UNDERFLOW.

The slowly moving ground water beneath a stream bed or valley is 

usually designated "the underflow." In order to estimate accurately 

the amount of ground water passing a given section, it is necessary to
HAMI.IN.] TTNDEBFLOW TESTS IN LOS ANGELES BASIN. 11

know, among other factors, the rate of movement or velocity of the 

underflow through the pervious beds below. This is conveniently 

measured by the method invented by Professor Slichter. a Briefly the 

method is as follows:

A group of four or five wells arranged as shown in figs. 9 and 10 is 

sunk at the -locality where the underflow is to be tested. Well A is 

placed upstream, or in the direction from which the underflow" is supposed to come, and the wells B, C, D, and E are spaced downstream 

at a uniform distance from well A. All of these wells are of small 

diameter (drive pipe, li to 2 inches) and have from 4 to 8 feet of perforated screen, usually ordinary well points, at the lower end. These 

perforations allow the percolating water to pass through the pipe 

driven into the pervious stratum to be tested. The upper well, A, is 

charged with a chemical, usually sal ammoniac (NH4C1). which dissolves in the water passing through the well and is carried along by 

the underflow to one or more of the lower wells which ones depends 

upon the direction of the underflow. The arrival at one of the lower 

wells of water containing sal ammoniac in solution is detected by 

means of electrical instruments.

METHODS AND APPARATUS USED IN UNDERFLOW TESTS.

In September, 1902, the writer was placed in charge of experiments 

to determine, if possible, the amount of underflow passing through 

the narrows of Los Angeles River at Huron street, Los Angeles, Gal.

Velocity measurements were begun under direction of Prof. Charles 

S. Slichter, with the apparatus invented by him. As the work progressed and tests at greater depths were made it was found necessary 

to modify this apparatus to suit local conditions.

LOCATION OF TEST WELLS.

The first step in testing the velocity of an underflow is to determine, 

approximately, the direction in which the underflow moves, and the 

second is to drill the test wells for measuring it. If the locality chosen 

is in a narrow valley or canyon bounded by rock walls, it is obvious that 

the underflow must be down the general trend of the valley. If, howe,ver, the tests are to be made in a wide valley or plain, it is advisable 

to ascertain the extent and slope of the water table in the vicinity.

If there are wells near, they should be located by some of the ordinary methods of surveying, and levels referred to some permanent 

bench mark should be run and the surface elevation at each well determined. The depth to water should be measured and the elevation of 

the water table computed. It is sometimes necessary to sink addi 

tional test wells, which should be located as just described. The data,

a Water-Sup, and Irr. Paper No. 67, U. S. Qeol. Survey, pp. 48-51.
12 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

should be platted on a map and contours, or lines of equal elevation, of 

the water table drawn, and the slope of the water table determined. 

The movement of the ground water in general is down the slope of the 

water table.

Fig. 21 (p. 42) is a map of the narrows of Los Angeles River at 

Huron street, Los Angeles, Cal., showing the extent and slope of the 

water table at that locality. The broken contour lines show the form 

of the water table in December, 1902; the dotted contour lines the 

form in June, 1903. The rise in the water table was due to the 

sinking flood waters of the Arro3ro Seco, which enters Los Angeles 

River a short distance below. Its channel is usually a dry wash of 

sand and bowlders, but was in flood during March and April, 1902, 

and the map shows plainly the sudden rise in the ground water due to 

the sinking of the storm waters.

A practical conclusion to be drawn from this map is that in order 

to avoid the disturbing influence of the fluctuations of a tributary 

stream the test wells should be located a considerable distance either 

above or below the mouth of such a stream.

When the slope of the water table and the approximate direction of 

the underflow have been ascertained, wells for testing the velocity 

should be sunk in groups arranged as shown in figs. 9 and 10 (pp. 

24 and 25). They may be sunk by any of several methods, depending 

on the locality, depth to the water table, coarseness of material, etc.

HAND DRIVING.

For shallow wells in unconsolidated material ordinary well points, 

as shown in figs. 2 and 3 of PI. I, A, may be used. These are screwed 

on a length of standard or extra strong wrought-iron pipe and simply 

driven into the porous strata. Two men using a heavy wood maul, 

as shown in PI. I, B, can drive such wells to a considerable depth, and, 

in such cases, this is a rapid and economical method. It is not possible, however, to collect samples of the material penetrated, and the 

porosity must be estimated from the amount of water yielded when 

the wells are pumped. This method was used in the first velocity test 

made in Los Angeles River, but was abandoned as unsatisfactory 

when deeper tests were attempted.

A portable hand rig is sometimes used to drive well points. Ordinarily two men can drive as many feet a day with a maul as with the 

hand rig in unconsolidated sands, unless the wells are deep. When 

used in combination with the hydraulic-jet method of sinking wells, 

such a rig will sink a pipe to a considerable depth, depending on the 

material penetrated, but when the material is coarse a point is soon 

reached beyond which it is impossible to drive any style of small pipe, 

as it is telescoped or battered by the hammer.
U. 6. GEOLOGICAL SURVEY

A WELL POINTS

WATER-SUPPLY PAPER NO. 112 PL.

B. DRIVING WELL POINTS.
HAMUN.] METHODS OF SINKING WELLS. 13 

WELL-DRILLING RIG.

When wells are to be sunk to a considerable depth, 100 to 150 feet 

for instance, in very coarse material, some kind of machinery is 

necessary. A rapid and economical method is a modification of the 

hydraulic-jet process of deep-well drilling by combination with driving. This method consists of three distinct processes (1) driving the 

pipe; (2) chopping up and washing out the sand and gravel that 

enters the bottom of the pipe as it is driven downward; (3) turning 

or rotating the pipe to keep the hole straight and to reduce the frictional resistance to driving. A rig equipped for this work, with the 

machinery assembled, is shown on PL II. It consists of the derrick 

for hoisting the heavy drivepipe, a hammer for driving the pipe, wash 

rods and chopping bit for hydraulicking, a pump for forcing water 

down the wash rods under pressure, and a rotator for turning the 

pipe. The whole is driven by a gasoline engine with a hoisting attachment. This machinery was designed to meet the local conditions of 

sinking wells to a depth of 100 to 150 feet in very coarse sharp sand, 

gravel, and bowlders. It has proved economical and satisfactory in 

actual use for several months.

MACHINE DRILLING.

When starting a well, a hole is first dug to a depth of 4 or 5 feet 

and a 10-foot length of drivepipe with a shoe firmly screwed on is 

inserted vertically, passing up through the rotator (a), as shown on PI. 

Ill, A. It must be plumbed carefully, for if it is not driven straight 

the wells will not be properly spaced at the bottom, and this will 

introduce errors into the velocity measurements. About 13 to 15 

feet of wash rod, with a chopping bit attached, is then inserted in 

the drivepipe, projecting about 3 feet above the top. The drive head 

(c) is then screwed on the drivepipe with the wash rods projecting 

up through the hole in the center. The buffer block (e) and hammer 

(f) should then be slipped over the wash rods which serve as a guide 

for the hammer, and the water swivel (g), with the hose attached, 

should be screwed to the top of the wash rods. The ropes for hoisting and driving and the sprocket chain for driving the rotator, etc., 

are attached as shown on PI. II, J., and PI. Ill, A.

The rig is operated as follows: Drive the pipe a few feet by tapping 

lightly with the hammer, then start the pump and force water down 

the wash rods and through the chopping bit. The rods should be 

churned up and down like a churn drill until the drivepipe is clear of 

sand to the bottom of the shoe. The chopping bit can be operated 

with, or independent of, the rest of the driving apparatus by a line 

passing over the middle sheave of the hoisting block. When the well 

is shallow the chopping can be done by hand, but when deep it is
14 UNDEBFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

necessary to use the winch or winding drum on the engine. The 

water swivel is made with a projecting base larger than the hole 

through the hammer (see fig. 7). By means of this device it is possible 

to drill with the chopping bit and at the same time drive the pipe 

with the hammer. The length of wash rods is so adjusted that the 

water swivel is 6 inches to 1 foot above the top of the hammer, when 

it rests on the drive head. As the ordinary stroke of the hammer is 1 

to 2 feet, the wash rods will be raised from 6 inches to 1 foot at each 

stroke. When the hammer is dropped the rods drop with it until the 

chopping bit strikes the sand in the hole, while the hammer still falls 

and almost instantly strikes the drive head. This is done automatically, 

the only attention required from the driller being the gradual lowering 

of the wash rods as the pipe is driven downward. The water which is 

forced out in jets through the chopping bit washes the pulverized sand 

and gravel up through the drivepipe to the surface. The drivepipe 

should be turned from three to five times per minute by an ordinary 

rotator such as is used with hydraulic-well rigs. The rotator should 

be run from the engine by a sprocket chain passing over sprocket 

wheels, as shown on PL II, B, and PI. Ill, A. When the wells are 

shallow two men with chain tongs can usually turn the pipe.

This method is particularly adapted to sinking wells in coarse sand 

and bowlders. The drivepipe should be double, extra-strong, steel 

pipe to secure the strength and stiffness necessary to prevent bending 

when forced through coarse materials, and its internal diameter should 

be at least 2i inches. It is sometimes very difficult to pull a long 

string of drivepipe, especially to start it. The only practicable way 

is to use jackscrews, as shown on PI. Ill, B, or use block and tackle 

with the engine at the same time turning the pipe with the rotator. 

Below is a more detailed description of machinery used.

APPARATUS. 

ENGINE.

In the selection of an engine, consideration must be given to the cost 

of fuel, transportation facilities, weight of machinery, etc. When 

fuel is expensive and water scarce, a gasoline engine will be found 

economical. For ordinary drilling when the depth of the wells does 

not exceed 150 or 200 feet, a 6 to 8 horsepower engine will furnish 

the necessary power. A very convenient type of engine is shown on 

PL II, B. It is a vertical gasoline engine geared to a hoisting drum, 

which is controlled by means of a friction clutch and brakes. The 

drum is used to raise the hammer and wash rods, for hoisting pipe, etc. 

From ten to twenty blows per minute can be struck with the hammer 

in driving pipe. The small winch on the engine is used for pulling
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 112 PL. II

A. WELL-DRILLING RIG.

B. WELL-DRILLING MACHINERY.
HAMLIN]. APPARATUS. 15

pipe, moving heavy weights, moving the engine, etc. The engine is 

belted to a force pump, which supplies water for hydraulicking, and is 

connected to the rotator by a sprocket chain. The engine shown in 

the cut is but 3 horsepower and is too light for deep wells, but has 

proved very economical in fuel consumption, using but 3 to 4 quarts 

of gasoline per day in ordinary drilling; in addition it has required 

but little attendance, is light, and easily moved.

PUMP.

The pump should be a suction force pump, capable of delivering 

water under a pressure as high as 150 pounds per square inch, with a 

discharge of 20 to 50 gallons per minute. It should be provided with 

a safety valve to prevent excessive pressure. The pump must be able 

to draw a supply from one to two driven wells, when the water table 

is within reach. In other cases it will be necessary to haul water for 

hydraulicking an expensive and troublesome method.

Connection between the pump and the wash pipe, as shown in PI. 

II, A and B, and PI. Ill, A, is made by means of 25 to 30 feet of 

flexible hose of good quality to withstand high pressure. Ten to 15 

feet of 2-inch suction hose will be needed to connect the pump with the 

drive wells from which the wash water will usually be pumped.

LIGHT DRIVEPIPE.

For shallow wells driven by hand in unconsolidated material the 

ordinary standard or extra-strong pipe will answer for drivepipe. It 

can usually be pulled and used several times. The outside couplings 

of such pipe greatly increase the f rictional resistance in driving and 

pulling, and a considerable percentage of pipe is sure to be left in the 

ground. Extra-strong pipe is sometimes fitted with flush-joint couplings, but so much metal is cut away at the joint that they are frail 

and will not withstand hard driving, breaking at the joint when the 

pipe does not go down straight.

HEAVY DRIVEPIPE.

For deep wells the drivepipe should be what is known to the trade 

as double-extra-strong steel pipe with joints flush inside and out. 

The inside diameter of the drivepipe must be at least 2£ inches. The 

nearest commercial size to this is known as 3-inch pipe; its actual 

diameter is 3i inches outside and 2.284 inches inside, the thickness of its shell 0.608 inch and its weight 18.56 pounds per linear 

foot. Rings of tough Norway iron of the same diameter and thickness as the pipe, and 6 or 8 inches long, should be welded on both

IKR 112 05 3
16 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

ends of each length of pipe, in which the flush-joint coupling should 

be turned. A taper thread with butt joints, as shown in fig. 1, has 

been found satisfactory and stands much hard usage. This form of 

thread has the advantage of a firm bearing throughout its entire length 

when it is screwed up tight. The pipe should be finished in lengths 

of exactly 10 feet with a few additional short 

lengths of 5 feet. A H to 2 foot length (5 on 

PI. Til, A.) should also be provided with a 1£- 

inch hole drilled through it about midway of 

its length to allow the wash water and sand to 

run out; the drive head should be screwed on 

the upper end of this short 

length. Such a drivepipe 

is stiff and heavy enough to 

stand repeated blows from 

the hammer. The fact that 

there are no outside coup- 

-J, lings make it far easier to 

drive and pull than the ordinary pipe.

SHOK.

The lower end of the 

drivepipe must be protected 

from injury by a shoe. The 

form shown in fig. 2 has 

been found satisfactory. It 

should be turned out of 

tough steel, the outside diameter being a trifle greater 

than the outside of the drivepipe, and the inside diameter the same. If it is to be used with a rotator 

the cutting edge should be notched and well tempered, as it will then cut its way downward 

more readily. The threads should be the same 

as on the drivepipe, so that it will fit on any 

length.

DKIVE HEAD.

8 tlireads to l inch 

6 teeth. 1 inch long

.Bottom plan

PIG. 1. Heavy drivepipe.

FIG. 2. Drive shoe.

The drive head, as shown in fig. 3, should be made of steel, accurately turned to fit the drive pipe on which it is screwed, and strong 

enough to withstand long-continued driving. The wash rods pass up 

through the hole in the center of the head, serving as a guide for the 

hammer (see c on PI. Ill, A). The four holes drilled in the side are
3EOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 112 PL. Ill

A. ROTATOR AND DRIVING MACHINERY. B. JACKSCREWS.
HAMLIN.] APPARATUS. 17

sockets for rods used in screwing on the head or in handling the pipe. 

A bail for lifting can be sprung into these holes, if desirable, but an 

eyebolt passing through the hole in the center and loosely fastened with 

a nut and washer inside the drive head will act as a swivel and be found 

stronger and more convenient when pulling pipe, hoisting, etc.

BUFFER BLOCK.

A wooden block should be placed between the hammer and the drive 

head to prevent the destruction of both. A convenient form is shown

SeotLoxi on line A-B 

Top view H 

SecWao. on ttne A-B

2 $ 4 8 ft Indhea

FIG. 3. Drive head. FIG. 4. Buffer block.

a-inehes

in fig. dt. It is simply an oak or other hardwood block with the grain 

of the wood vertical, securely bound with an iron band. A hole should 

be bored through the middle and the block may then be slipped over 

the wash rods and rest on the drive head, as shown at e on PI. Ill, A.

HAMMER.

A hammer of the form shown in fig. 5 requires no guides, but slides 

up and down on the wash rods. It may be made of cast iron with projecting- ears for attaching the hoisting ropes. When it is necessary to
18 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

add a length of drive pipe, the hammer can be raised off the wash rods,

swung to one side, and lowered to the ground. It is raised and lowered

independently of the wash rods by means of two ropes, which pass up

Section on line A4B through the outside sheaves of the

hoisting block at the apex of the 

derrick and thence to the winding 

drum of the engine, as shown on PL 

II, J., and at f on PL III, J..

WASH RODS.

The wash rods should be made of 

what is known as double-extra-strong 

1-inch pipe, the diameter being 1.315 

inches outside and 0.587 inch inside, 

the thickness of the section on ATB 

shell 0.364 inch, and 

the weight 3.65 pounds 

per linear foot. The 

rods-should have rings 

of Norway iron on each 

end and the same style 

of taper thread as the 

large drive pipe shown 

in fig. 1. When finished, the rods should 

be exactly 10 feet in 

length, but several 5- 

foot and 2-foot pieces

Section on line O^D should also be on hand. 

FIG. 5. Hammer. If deep wells are to be 

drilled, heavier wash rods will be necessary. This will 

require larger holes than those figured in the drive head, 

buffer block, and hammer.

CHOPPING BIT.

The chopping bit should be made of best tool steel. A ' -2L 

drawing of the bit in use is shown in fig. 6. It should be 

securely welded to a 5-foot length of wash rod instead of 

being screwed to it, otherwise when drilling in coarse 

material or bowlders it will probably be broken off and 

lost in the we'll. The, cut shows the bit welded to a length 

of double-extra-strong li-inch pipe, commercial size.

The edges of the star bit should not be drawn down too thin, and 

must be well tempered to withstand hard usage, for when drilling

Bottom plan showing

beveled edgee of

chopping bit.

FIG. 6. Chopping

bit.
HAMLIN.] APPARATUS. 19

the impact of the heavy string of wash rods, when dropped several 

feet, must be borne by the chopping bit. The holes through the 

bit should be of ample size to deliver enough water to raise the pulverized sand and gravel to the surface and 

still must be small enough to give the 

issuing jet a high velocit}\

WATER SWTVEL,.

A swivel connection between the hose 

and the wash rods is necessary to permit 

turning the chopping bit, making connections, etc. The form shown in fig. 7 

has been found convenient. It should be 

strong and well made, as the hammer 

engages with the lower part of the swivel 

in raising the wash rod. As sand and 

gravel in the drive pipe sometimes pack 

around the drill and rods, the pull on 

the swivel may be considerable, perhaps 

enough to stop the engine, in which case 

the wash rods must be jarred loose by 

upward blows with the hammer.

DERRICK.

The derrick may be made of three timbers, about 4 by 6 inches, and 30 to 36 

feet long, as shown in PL II, A. Holes 

are bored through the top and the timbers 

loosely connected by a 1-inch bolt, from 

which is suspended a long clevis, to which 

the hoisting blocks are attached. Such a 

tripod, can be quickly raised, lowered, or 

adjusted over a well. Slats nailed on the 

timbers serve as a ladder for reaching 

the top.

BLOCKS.

FIG. 7. Water swivel. The lines from the hammer should be 

run up over the outside sheaves of a triple block, and then to the 

winding drum of the engine, as shown in PI. II, A. The line from 

the wash rods is run over the center sheave and then fastened to 

a cleat on one leg of the tripod. By this arrangement the rods can 

be easily raised or lowered by hand, or suspended at any height.
20 UNDEKFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

A double block should be provided for use with the triple block in 

pulling the drive pipe, moving the engine, etc.

WELL POINTS.

When wells are shallow and the material to be penetrated is soil or 

unconsolidated sand, it is economical to drive ordinary 1£ or 2 inch 

points. These are usually in 4-foot lengths and are made by perforating standard or extra-strong wrought-iron pipe with seven rows of 

oblong holes three-eighths by one-half inch. Around the outside of 

the perforated pipe is wrapped a fine brass screen of No. 35 wire with 

about 2,500 meshes per square inch; over the gauze is wrapped a perforated brass screen with 28 one-eighth inch holes per square inch, the 

whole being securely soldered to the perforated pipe along the vertical 

seam. The gauze strains out the fine sand and silt, but allows the 

water to enter the well, and the brass screen is put on to protect the 

gauze. Fig. 1 of PI. I, A, shows such a well point with the screen and 

gauze partly removed. This style of point serves for both a well and 

for part of the testing apparatus as described on page 26.

When the material is compact, or contains cobblestones or bowlders, 

these well points fail, either by bending, by breaking, or by stripping 

off the outside screen and gauze. If the material contains stones 

large enough to deflect the pipe, it will bend and either break in driving or in pulling; in fact, it is almost impossible to pull a crooked 

pipe, as it will break at one of the couplings. When the material is 

compact and coarse the frictional resistance on the screen will often 

strip it entirely off of the pipe, leaving it as shown in figs. 1 or 3 of 

PI. I, A. To overcome these difficulties the experiment of placing a 

fine screen on the inside of the perforated drive pipe was tried and 

found quite satisfactory. Perforated sheet brass, known to the trade 

as No. 26 gage, No. 1, with 400 holes, about 0.02-inch in diameter per 

square inch, should be rolled into a tube slightly smaller than the 

inside diameter of the perforated pipe (fig. 5 of PI. I, J.), securely soldered along the vertical seam and shoved inside the perforated pipe, 

where it is held in place by the couplings above and below. It is largely 

protected from injury and can be withdrawn and cleaned if necessary. 

Such a well point is shown in fig. 4 of PL I, A. The only objection 

to this style of point is that the holes in the outside tend to fill with 

sand and clay when the pipe is pulled.

JACKSCREWS.

The jackscrews for pulling pipe should be strong, of at least 32 

tons capacity each. A clamp of heavy flat iron, a pulling ring, and 

steel wedges or dogs with notched edges should be provided for hold-
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 112 PL. IV

ELECTRODES AND WELL.
HAMLIN.] APPARATUS. 21

ing the ring in place when the pipe is being pulled. The arrangement 

of the jackscrews, etc., is shown on PI. Ill, B,

PLACING WELL POINTS FOR UNDERFLOW TESTS.

As noted above, ordinary well points are driven into the pervious 

strata where it is proposed to test the underflow.

When the heavy drivepipe is used the procedure is somewhat different. The pipe is driven by machinery to bed rock, or to the desired 

depth, and thoroughly cleaned from sand, silt, etc. A length of well 

screen similar to that shown in fig. 4 of PL I, A, is screwed to a 

sufficient length of li-inch standard pipe and lowered to the bottom 

of the hole. The drivepipe is then pulled up, leaving the well screen 

and l^-inch pipe in the ground with the screen at the proper depth. 

The drivepipe is used to sink another well, in which is placed another 

screen, etc., until all the well screens of the group are in place. The 

well screens and small pipe, whether set by the first or the second 

method, now form part of the testing apparatus, being a portion of 

the electric circuit.

TESTING APPARATUS.

The various instruments at first used in testing the velocity of 

underflow were made from designs furnished by Prof. Charles S. 

Slichter. The modifications of the original apparatus and the 

methods developed are the result of several months' experimenting 

by the writer, and may be of value to investigators in the future.

WIRE.

The wire should be a good quality of rubber-insulated copper, about 

No. 14. Single wires are more convenient than a cable or a twisted 

lamp cord. Care must be used and the wire examined occasionally to 

see that the insulation is not worn through, for if it is there will 

probably be a short circuit between the well casing and the wire. It 

should be kept rolled into open coils, and not kinked or twisted, as 

such usage tends to break the insulation.

ELECTRODES.

The electrodes are brass rods from one-fourth to five-sixteenths inch 

in diameter and about 4 feet long, usually nickel plated (PI IV). 

They should be heavy, of solid metal throughout, as it is difficult to 

sink a light electrode to the bottom of a deep well. The wire should 

be attached to the electrode by some such device as that shown in fig. 8, 

this being necessary in deep wells. It should not be bent or kinked 

where attached to the electrode, as it may break and leave the elec-
22 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

Top insulator 

I I

trode in the bottom of the well. The electrodes are insulated from 

the well casing by means of wooden blocks (see fig. 8), which should 

be boiled in paraffin to make them impervious to water. The electrodes will need frequent 

plating, as the action of the 

electric current and of the 

sal ammoniac quickly corrodes the nickel coating.

SWITCH CLOCK.

A switch clock found satisfactory in actual use is shown 

in PI. V. It is an ordinary 

eight-day clock with electrical devices added. The minute hand of the clock carries 

a steel spring, tipped with 

platinum, which, at five-minute intervals, is brought into 

contact with platinum strips, 

each of which is connected 

with a separate insulated wire 

passing down through the 

clock case and thence to the 

proper binding post. Each 

contact closes a circuit 

through one of the test wells. 

The platinum strips are laid 

in slits cut in lugs of hard 

rubber. The strips, the projection of which beyond the 

edge of the lug is adjustable, 

are held in place by screws 

which pass through narrow 

slots. The hard-rubber lugs 

are permanently fastened to 

the clock dial by screws from 

the back. They are placed 

at each hour on the dial or at 

five-minute intervals as measured by the minute hand. 

In operating, the spring on the minute hand is carried over the hardrubber lug, which is so placed that the spring is slightly raised. When 

the tip of the spring reaches the sharp edge of the lug it suddenly 

snaps down on the platinum strip and at once closes the circuit. It is

Jr..

Bottom insulator 

FIG. 8. Electrodes.
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 112 PL. V

E D C B

SWITCH CLOCK.
HAMLIN.] APPABATUS. 23

pulled across the platinum strip by the motion of the hand and when 

it reaches the edge snaps away from the strip, suddenly opening the 

circuit. The time the circuit is closed can be regulated by adjusting 

the width of the strip. Five to ten seconds is about the proper interval. It is important that the circuit be opened and closed suddenly, 

otherwise the recording pen, full of ink, may move back and forth on 

the chart several times and probably obliterate the record.

The current from the positive pole of the battery enters the clock 

at one of the binding posts, B, (7, D, E, etc., and passes through the 

insulated wire to the minute hand, thence to the clock frame and out 

to the binding post marked A. By the movement of the minute hand 

the circuits to the various wells are progressively closed. The twelve 

switches on the dial permit of thirty hourly records with four lower 

wells and a thirty-minute interval between records, as shown on Pis. 

V, A, and VI, B, or of records at intervals of twenty minutes with 

three lower wells and a ten-minute interval between records. It is 

also evident that in the first case two groups of wells, or in the second 

case three groups of wells, can be tested hourly at the same time, 

with a ten-minute interval between tests.

RECORDING AMPERE METER.

The recording ampere meter (PI. VII, A} was made by the Bristol 

Company from designs furnished by Prof. Charles S. Slichter. The 

instrument keeps a continuous record for twenty-four hours, after which 

the chart must be changed. The chart is moved at a uniform rate by 

clockwork. The recording pen is actuated by the electric current 

sent through the wells at fixed intervals by the switch clock. The 

electric apparatus is very simple, consisting of a stationary solenoid 

through which the current passes. A thin disk of soft iron is attached 

to a nonmagnetic shaft which passes through the solenoid and is supported at its opposite ends by steel knife-edge springs. The recording pen is secured directly to the steel springs and partakes of its 

angular motion as the disk is attracted by the solenoid. The result is 

a record such as shown on PI. VI, A and B.

If an ordinary ampere meter is used the switching must be done 

by hand, as described on page 27.

BATTERY.

The electric battery should be of ample capacity. Dry cells known 

as large-size Columbia, 3i inches in diameter and 8 inches high, have 

been found satisfactory. The plan and wiring of the battery for use 

with a recording ampere meter only are shown in fig. 9, and for use 

with either a recording or ordinary ampere meter are shown in fig. 10,

IRK 112 05 4
24 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

The battery consists of 12 large-sized dry cells connected in sets of 

two in parallel. These parallel sets are connected up in series, and by 

means of the double-throw switches the electromotive force of the 

battery can be varied from 1.5 to 9 volts, assuming the electromotive 

force of each cell to be li volts when new. One, two, three, or more 

sets of two cells connected in parallel can be used in one series, as the 

case requires, or if necessary either side of the battery can be cut out 

by the opening of one of the single-throw switches marked " A, A'." 

An ordinary ampere meter should, for convenience, be placed in the 

battery box. Fig. 10 shows such a battery connected up to a group 

of four wells and arranged for use with an ordinary ampere meter. 

The switches are set for measuring the current from casing of well B 

to the electrode of well B, with two sets of cells in series.

FIG. 9. Plan of test wells and apparatus. 

METHOD OF MEASURING THE VELOCITY OF UNDERFLOW.

An outline of the method invented by Prof. Charles S. Slichter has 

been described on page 11. The following is a description more in 

detail of the writer's experience during several months' work at Los 

Angeles, Cal. An attempt hq,s been made to describe the difficulties 

encountered and the methods developed during the progress of the 

work.

PUMPING.

After all the test wells have been sunk, as described on page 11, it 

is necessary before beginning a test to take a small sand pump and 

thoroughly clean the inside of the well points from sand and silt, and 

then pump water from each well until it clears. A small hand pump 

which can be readily moved from well to well is convenient for this
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 112 PL. VI

CHARTS USED WITH RECORDING AMPERE METER.
HAMLIN.j METHOD OF MEASURING VELOCITY. 25

purpose. Pumping is often a tedious job, as the screens become 

clogged with silt and mud. In such cases a few buckets of clear 

water poured down the well will often open up the screen. Another 

way is to occasionally break the vacuum in the pump and let the water 

in .the pipe fall back suddenly. When these methods fail, success may 

be attained by rotating the pipe with a pair of tongs and at the same 

time pouring clear water down the well.

If some of the wells pump freely and the rest will not start, it is 

almost certain that the screens are clogged, and if all else fails they 

may be allowed to stand a day or two. If none of the wells can be 

started, or after starting 

continue to pump fine 

sand and mud, the test 

may as well be abandoned, for in such cases 

the velocity will be too 

low to measure by this 

method. Testing should

not be begun for a few 

hours after pumping, in 

order to allow the water 

plane to rise to its normal 

level.

WIRING.

The next step is to 

wire the wells. There 

are several ways in which 

this may be done, depending on the kind of 

electrical instruments 

used. If a recording 

ampere meter is used, 

the wiring should be as 

shown in fig. 9. A wire 

is run from the positive pole of the battery to the casings of lower 

wells B, C, D, E, etc., all of which may be connected by soldering 

the wire to the galvanized casing of each, thus insuring good connections. A wire is connected to the electrode for each well and 

run to the proper binding post on the switch clock; the electrodes 

should then be lowered to the bottoms. From the positive binding 

post of the switch clock a wire is run to the recording ampere meter, 

and from the ampere meter to the negative pole of the battery. 

An ordinary ampere meter (in the battery box) is put in the circuit to 

check the record of the recording instrument.

PIG. 10. Plan of test wells and apparatus.
26 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

The current recorded is that which passes through the water 

between the casing of the wells and the electrode at the bottom of the 

well.

The construction of the clock, recording ampere meter, battery, etc., 

is described on pages 21 to 24.

If an ordinary ampere meter is used the wiring will be quite different, as all switching must be done by hand. A battery arranged for 

such a testing and the wiring of a group of wells is shown in fig. 10. 

A wire should be run from the proper binding posts, marked A, B, C, 

D, and E, of the battery to the casing of the corresponding wells, and 

another from the binding posts, marked B', C', D', E', of the battery 

to the electrodes of the corresponding wells. The battery is so wired 

that when the switches A and B are closed, the ampere meter indicates 

the amount of current flowing through the ground from the casing of 

well B to the casing of well A. When the switches B and B' (fig. 10) 

are closed, the ampere meter indicates the amount of current flowing through the water from the casing of well B to the electrode of 

well B. After all the wiring is done, the correctness of the various 

connections should be tested. If the circuit through one of the wells 

is closed and the electrode lifted out of the well, the amperemeter needle should fall back to zero, for raising the electrode out 

of the well opens the circuit. On the other hand, if the casing of the 

well is touched with the electrode, a strong deflection of the needle 

should be noted. By these tests an error in wiring may be detected.

CHARGING WELL, A.

After all the connections have been made and tested, a new chart 

should be placed in the recording ampere meter, and the apparatus 

allowed to run for an hour or so, to get a record of the wells before 

well A is charged.

Various methods of charging wells have been tried, and the following has finally been adopted. The electrolyte used is sal ammoniac 

(NH4C1). This should be placed in a small wooden or paper tub (it 

rusts iron quickly) and enough water poured on to cover it. A bucket 

of perforated sheet brass, similar to that used for the inside screen of 

the well points, about 4 feet long and small enough to readily slip 

down the inside of the well pipes, should be provided. This should be 

placed in the tub of wet sal ammoniac and filled with water and the salt 

by means of a funnel and dipper. The water will drain away into the 

tub and leave the wet sal ammonia filling the bucket, which should at 

once be lowered to the bottom of the well.

It is difficult to get a bucket of dry sal ammoniac down a deep well 

on account of the contained air. In addition, the escaping air causes 

the formation on the water of a sticky foam', which is carried down by
U. S. GEOLOGICAL SURVEY

A. RECORDING AMPERE METER.

B. BATTERY.
HAMUN.] METHOD OF MEASURING VELOCITY. 27

the next bucket and clogs the screen. The experiment of pouring a 

hot saturated solution of sal ammoniac down the well pipe was tried, 

but was condemned. It will either crystallize out when the water cools 

and leave the pipe filled solidly with the salt, or, if the strata be pervious, will be forced through to the lower wells almost immediately. 

In any case, undissolved sal ammoniac should not be poured down a 

well, as it is almost impossible to clean it out for the next test.

The following rule is now observed in charging wells: Put down 

one bucket of wet sal ammoniac every fifteen minutes for two hours, 

then one bucket an hour for six hours. Of course, if at any time the 

electrical instruments show that the sal ammoniac has reached the 

lower wells, charging should be stopped at once.

DETEKMINATION OF VELOCITY OF UNDERFLOW.

When recording instruments are used, it is only necessary to examine them occasionally to ascertain when the sal ammoniac reaches the 

lower wells. Its arrival is indicated by an increased deflection of the 

recording pen, as shown by the chart in PI. VI, A. When the velocity 

is great the deflection is sudden, but when it is low the increase is not 

so marked. When there is no underflow the deflection of the pen 

remains the same throughout the test, as shown in PI. VI, B.

When an ordinary ampere meter is used, the circuits to the various 

wells must be closed by hand at frequent intervals, varying from ten 

minutes to two hours, depending on the velocity of underflow. When 

it is probable that the velocity is great, readings must be made often; 

but if no flow is detected for two or three hours, the time between 

observations may be longer. The ampere meter must be read and the 

time and readings recorded in a notebook. From the notes an ampere 

curve should be platted (fig. 11), from which an estimate of the velocity 

of flow can be made. The sudden rise in the curve indicates the 

arrival of the sal ammoniac at the lower well. This rise is primarily 

due to the fact that the solution of water and sal ammoniac is a better 

conductor of electricity than is water alone, and when this solution 

flows into and mingles with the pure water in the well, the rise in the 

current, due to lessened resistance, can at once be noted.

The time of passage of the solution from well A to one of the lower 

wells is usually calculated from the hour when charging was begun to 

the hour when the rising ampere curve reverses, or, in other words, 

at the point of the maximum rate of increase in the ampere curve. 

This method corrects for the diffusion or spread of the sal ammoniac 

in the water and for the error due to the fact that the water in the 

upper well can not be charged quickly.

The distance between the wells being known and the time of passage 

of the solution having been noted, it is a simple matter to compute the
28 UNDERFLOW TESTS LOS ANGELES BASIN. [NO. 112.

velocity or rate of flow. This may be expressed in any unit of measure desired. In this report the rate of flow is expressed in feet 

per day.

When wells have been sunk with the heavy drivepipe, as described 

on page 21, and the well screens inserted, the first test will evidently 

be at bed rock, or at the bottom of the hole. After the completion of

yeptk of wells

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FIG. 11. Ampere curves.

the first test, the pipe may be pulled up the length of the screens and 

another test made. This pulling up and testing may be continued to 

the level of the water table if desirable.

When well points are driven by hand, it is best to drive into the 

first stratum below the water table, test it, and then drive deeper, continuing the process as far as necessary.
UNDERFLOW TESTS IN LOS ANGELES BASIN. 29 

COMPUTATIONS OF DISCHARGE.

In a given section wide differences in the velocity of underflow are 

to be expected, due to the various factors on which flow depends, such 

as slope of the water table, porosity, relative size of the sand grains, 

temperature, etc. It is evident that if the actual percentage of the 

open spaces or voids between the particles of sand and gravel of each 

square foot of a measured section was known, and the average velocity 

at which water flows through the ground had been measured, it would 

be possible to compute the amount of water passing a given line during a fixed interval of time; moreover, no further data would be 

necessary.

The difficulties met with when an attempt is made to compute the 

discharge from a section should be clearly set forth.

Natural sands, as dug from pits or the bed of a stream, consist of 

grains of different sizes and shapes. Such sand weighs more per unit 

of volume, as per cubic foot, than any of the various grades of sand 

sifted from the same bed and having grains of nearly uniform size. 

This proves that the natural sands contain a less percentage of voids, 

or, in other words, the porosity is less, than that of the sorted sands.

Experiments made by Prof. F. H. King® show that the porosity of 

unsorted sands from the Tujunga washes in San Fernando Valley, Los 

Angeles County (see fig. 12), varies from 31.42 to 42.28 per cent. 

The effective diameter of the sand grains was ascertained to range 

between 0.05542 and 0.4289 millimeters. The same writer says:

It appears to be generally true that well-rounded grains of nearly uniform diameter 

tend to give a pore space which lies between 32 and 40 per cent. The mean theoretical pore space for spherical grains of a single size is 36.795 per cent, and this is 

very close to the mean observed limit for the more simple sands of rounded grains.

A sample of coarse sand from Arkansas River Valley was tested by 

G. W. Stose in the following manner:

After being thoroughly dried it was saturated with water, and the quantity of 

water received was determined by weighing. The vessel containing it was then 

ptinctured at the bottom, so as to permit the water to drain away, and after a lapse of 

several days the loss of water was determined by another weighing. It was then 

found that the sand had received 29 per cent of its volume of water, but afterwards 

parted with only one-third of the water received, equivalent to 10 per cent of the 

whole volume of sand. &

Both of these samples had been removed from the original beds. 

The experiments show the probable range of porosity in clean sand 

of moderately uniform size.

Prof. Charles S. Slichter states that "the porosity of quartz sand 

will usually vary between 30 and 40 per cent, and that of clay loams

a King, F. H., Nineteenth Ann. Kept. U. S. Geol. Survey, pt. 2,1899, p. 212. 

i> Gilbert, G. K., Seventeenth Ann. Kept. U. S. Geol. Survey, pt. 2,1896, p. 600.
BO UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

between 40 and 50 per cent, depending upon the variety of sizes in 

the mixture and the manner of packing the particles." a

Very little is known regarding the porosity of naturally deposited 

and undisturbed beds composed of coarse gravels, coarse and fine sand, 

and silt. Theory indicates that such beds, having been deposited by 

the action of running water, or by the waves and currents of the 

ocean, are far less porous than sands of uniform size, the sorting 

action of the water tending to pack the material as closely as possible.

It is usual to assume that the porosity of sand is about 33 per cent, 

and if the grains are rounded, of nearly uniform size, and free from 

silt, the assumption is, without doubt, about correct.

The actual porosity in each case must be known before any reliable 

computation of discharge can be made. Concerning this factor, Professor Slichter says:

If two samples of the same sand are packed, one sample so that its porosity is 26 

per cent and the other sample so that its porosity is 47 per cent, the flow through 

the latter sample will be more than seven times the flow through the former sample. 

If the two samples of the same sand had been packed so that their porosities had 

been 30 and 40 per cent, respectively, the flow through the latter sample would have 

been 2.6 times the flow through the former sample. These facts should make clear 

the enormous influence of porosity on flow, and the inadequacy of a formula of 

flow which does not take it into account. &

Evidently beds which consist of a mixture of bowlders, cobblestones, 

fine sand, and silt will have a less percentage of voids than graded 

sand. No flow can occur through bowlders or cobblestones, and if 

they make up 50 per cent of the volume, and the intervening spaces 

are filled with sand and silt of graded sizes, there is certainly far less 

than 33 per cent of voids in the mass. How much less must be 

determined by experiment.

It is exceedingly difficult in underflow tests to come to any satisfactory conclusion regarding the porosity of the various beds. This is 

due to the almost insurmountable difficulties in collecting representative samples of the material penetrated. If the testing is done with 

a small-size drive pipe, 2 to 4: inches, all the coarse material must be 

excluded, because it is impossible to get it into the pipe or to the surface. When the material is very coarse, it is obviously necessary to 

dig a well or shaft, or put down a large bore well, 12 inches or more 

in diameter. Both methods have decided limitations.

It is impracticable, by any reasonable expenditure of money, to dig 

a well much below the level of the water table. If a large-bore well 

is sunk, material below the water table must be brought to the surface 

in a sand bucket. The continual churning of the sand bucket under 

water washes the fine silt and mud out of the sand and mixes it with

asliehter, Charles S., The motions of ground water: Water-Sup, and Irr. Paper No. 67, U. S. Geol. 

Survey, 1902, p. 17. 

b Slichter, Charles S., Nineteenth Annual Report U. S. Geol. Survey, pt. 2,1899, p. 323.
COMPUTATIONS OF DISCHARGE. 31

the water in the well. This mixture of mud and water is partly bailed 

out with each bucket partly filled with sand. How much silt is 

washed out by the water at any particular point is, of course, impossible to say, but if one will catch the muddy water from the sand 

bucket and let it settle he will be convinced that it is usually no small 

amount. No one can tell exactly at what depth or how much of the 

sand contains silt. It is entirely possible that a bed of clay or silt a 

foot or more thick may be entirely mixed with the water in the well 

and no evidence of its presence be shown unless the driller notes 

that the water is more muddy than usual.

The writer has seen samples of sand taken from wells, carefully 

washed, cleaned from all silt, clay, etc., and then bottled up and exhibited as water sand. Any estimate of discharge based on such samples 

is utterly misleading.

Samples are often cqllected by catching the sand, etc., brought up 

by a hydraulic rig. Of course these samples are thoroughly washed. 

In porous gravel the wash water used in hydraulicking continually 

tends to flow away from the well, being under great pressure. That 

it carries the fine material near the hole away with it is proved by the 

fact that the sinking of the wash water when drilling in gravel can 

often be prevented by pouring clay down the well, which soon fills the 

voids in the surrounding gravel.

The hydraulic and drive-pipe method of sinking test wells has one 

great advantage over the sand bucket, in that the presence of a bed of 

clay or silt is shown at once by the muddy water which rises to the 

surface through the drive pipe. The depth at which such beds occur 

can by this means be ascertained.

Another uncertain factor is the unknown horizontal extent of the 

pervious beds. It can only be assumed that they extend from station 

to station, and in regions where the pervious beds have been deposited 

by torrential streams this assumption may lead to error, such gravel 

beds often being in the form of long trains of coarse material, the 

buried channel of the stream, and not in a wide extended sheet as 

supposed by many. To correct for this uncertainty, it is obviously 

necessary to sink test wells at close intervals along the cross section.

There is much uncertainty regarding the weight to be given velocity 

measurements. As a rule the velocities recorded are the maximums. 

Suppose test wells are set 4 feet in a pervious stratum, the upper two 

feet of which is composed of coarse sand 2 millimeters in diameter, 

the lower two feet composed of fine sand 0.4 millimeter in diameter, 

with a pressure gradient of 10 feet per mile. As computed from 

tables prepared by Prof. Charles S. Slichter, a the velocity of flow in 

the upper bed will be at the rate of 5,386 feet per year, and in the

n.Slichter, Charles S., The motion of underground water: Water-Sup, and Irr. Paper No. 67, U. S. 

Geol. Survey, 1902, p. 2a.
32 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

lower bed at the rate of 216 feet per year. In the first instance this is 

at the rate of 14.75 feet per day, and in the second at the rate of 0.59+ 

foot per day.

If the test wells are spaced 4 feet apart the chemicals used in charging the upper wells should pass through the coarse stratum and reach 

the lower well in about six and one-half hours, while it will take about 

one hundred and sixty-two and five-tenths hours for the same chemical 

charge to reach the lower well through the fine stratum. In such a 

case, the salt passing from the upper bed would enter the lower well 

and cause a sudden rise in the current, as recorded by the instruments. 

The sal ammoniac in solution, being much heavier than the ground 

water alone, will settle and fill the lower well. There is no doubt but 

that the result is correct for the upper 2 feet, but, as the lower well is 

full of the solution of sal ammoniac, there will be no means of ascertaining when the charge from the lower stratum reached the well, even 

if the test should be continued for six and three-fourths days, which 

is highly improbable. It is in fact impossible to know, in testing 

material naturally deposited, whether the flow is through the whole 

section tested or through one or two thin strata. The only practical 

method is to use short well points and test the ground at each few feet 

in depth.

The most promising field for this method of testing underflow is in 

regions where the pervious formations are uniform in composition and 

texture throughout wide areas, and where the water table is not subject to great fluctuations in level. If testing in mountainous regions 

or in the debris cones of torrential streams is attempted, the testing 

stations should be close together and tests made at many points and at 

various depths, to eliminate as much as possible the inaccuracies due 

to varying texture and porosity of the formations.

BASIN OF LOS ANGELES RIVER.

The drainage basin of Los Angeles River has an area of approximately 502.5 square miles.

The principal eastern tributaries of this stream rise on the west 

slopes of San Gabriel Mountains and flow down to San Fernando 

Valley in deep rocky canyons which have been eroded in the granitic 

rocks of the range (see fig. 12). These streams are torrents during 

the rainy season, but dwindle to mere rivulets in the summer. When 

in flood they transport a vast amount of detritus, sand, gravel, and 

bowlders to the plain below, and have buried the old drainage lines 

across the east end of San Fernando Valley beneath extensive detritus 

cones, into which the surface streams sink except in times of extraordinary floods.

The western tributaries of Los Angeles River rise in Santa Susanna 

Mountains, which bound San Fernando Valley on the north, and in
HAMLIN.] DESCRIPTION OF LOS ANGELES BASIN. 33

Santa Monica Mountain.s on the south. These streams are small, 

rarely reaching the eastern end of the valley. They flow over sandstones, shales, clays, etc., and are strongly impregnated with alkaline 

salts, in strong contrast to the pure water from the granitic range to 

the east.

After flowing southerly in a broad underground channel beneath 

the detritus in the east end of San Fernando Valley, the water of 

Los Angeles River is deflected easterly by the impervious rocks of 

Santa Monica Mountains. This barrier, taken together with the contraction of the underground channel, so obstructs the free percolation 

below that much of the ground water rises and flows as a surface 

stream again.

PACIFIC OCBJL3

FIG. 12. Drainage basin of Los Angeles River.

After rounding the eastern end of Santa Monica Mountains the 

river flows through a region of low, rolling hills in a valley which is 

about 2^ miles across at the widest place and narrows to half a mile at 

Los Angeles, 6 miles below. This valley was formerly deeper than at 

present, and, in common with San Fernando Valley above, has been 

partially filled with river detritus, which near the mountains is very 

coarse but becomes fine and contains beds of sand and silt toward 

the south. The gradual change from coarse to fine material in connection with the contraction of the underground channel without 

doubt causes the rise of ground water along this 6-mile section of the 

river. At the mouth of the Arroyo Seco a marked change occurs in 

the character of the stream detritus. This stream is steep-graded and 

torrential, heading on the precipitous slopes of San Gabriel Mountains 

(see fig. 12). After leaving the mountains it flows in a canyon cut
34 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

across the hill country to its junction with Los Angeles River. It 

carries bowlders, coarse gravels, and sand into the river valley, and its 

wide-spreading debris cone at the mouth of the canyon has forced 

Los Angeles River to the southwest side of the old valley. There is 

evidence that this debris cone was once more extensive than now, and 

it without doubt then acted as a barrier to the flow of the river, thus 

perhaps accounting in a measure for the fine material in the valley 

immediately above. About 2 miles below Huron street the river 

flows out on an alluvial plain and the surface stream soon sinks.

Lower Los Angeles River, extending from Huron street 12 miles 

northwesterly, being supplied b}^ underground water, is remarkably

XiOg of weJQ Underflow tests

Silt and sand ir

oo'i

 p

to

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P

s

jS

i

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i

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0

£

o

£

27.0'

Vertical «scale 

10 20 30 feet

FIG. 13. Underflow tests at station 1.

uniform in its discharge, little difference being noted throughout the 

year. The entire surface and part of the underflow is diverted by the 

city of Los Angeles for domestic use and irrigation.

TESTS IN 19O2.

The following preliminary tests were made in Los Angeles River 

valley during September and October, 1902. The tests made at 

stations 1 and 2 were mainly for the purpose of adapting the apparatus 

to local conditions.

STATIONS AND RESULTS.

Station 1 is in Los Angeles River bed, at the Los Feljs road bridge, 

near Huron street (see fig. 21). A group of well points was driven
HAMLIN.] TESTS IN 1902. 35

by hand to a depth of 11 feet. The velocity of the underflow was 27 

feet per day between 3 feet and 11 feet, and the movement was S. 80° E., 

or away from the surface stream, which was actually losing water at 

this point. Later the water table was found to slope in the direction 

indicated by the underflow. The order of the strata, record of the 

wells, and the velocity measurements at this station are shown in fig. 

13. Sixty-five feet to the east of this station another group of well 

points was driven to a depth of 11 feet and tested between 3 feet and 11 

feet, but no underflow was detected. They were then driven to a 

depth of 19 feet, and tested between 11 feet and 19 feet, with the same

v Log of well Underflow teats

Sand and silt 9'6'

If?

9 6

-pin

0)

<H

O

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1

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<R

 a

fl£

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VerticalJScale 

10 20 «0 feet

FIG. 14. Underflow tests at station 2.

result. As these were driven wells no samples were collected, but the 

material appeared to be fine silt except near the surface, where it was 

somewhat sandy, and it is probable that the underflow at station 1 

was through this top stratum.

In August and September, 1903, the Southern Pacific Railroad Company dug pits for bridge piers in the river bed about 100 feet east of 

this point. The material penetrated was mainly mud and silt, with a 

few irregular seams of sand. Only the sand beds were water bearing; 

they are from 2 to 4 inches thick.

Station 2 is on the west side of the river, 1 mile above the Huron 

street section, as shown in fig. 12. A group of well points was driven
UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

by hand to a depth of 9i feet, and a test made between 1£ feet and 9£ 

feet, showing the direction of the underflow to be S. 5° E., velocity 

5 feet per day. No samples of the strata pierced were collected, but 

the amount of water pumped indicated that the ground was not porous. 

The order of the strata, record of the wells, and the velocity measurements are shown in fig. 14.

The testing apparatus was then moved upstream to San Fernando 

Valley, where the conditions of underflow and the extent of the ground

Log of well TJ;uderflo\y tests

Sarnd and. sUb 14' 6U

146"

8&8

6'6

22 6

17.0'

Vertical Scale 

10 20 30 feet

FIG. 15. Underflow tests at station 3.

water have been thoroughly studied. The object of these tests was to 

determine, if possible, the relation of the slope of the water table to 

the direction and velocity of the underflow.

Station 3 is on the east bank of Tujunga Wash, near its junction 

with Los Angeles Eiver, as shown in fig. 12. A group of well points 

was driven by hand to a depth of 14i feet, and a test made between 

6i feet and 14£ feet, where the direction of the underflow was S. 23° 

E., velocity 17 feet per day. The wells were then driven deeper and 

a test made between 14£ feet and 22£ feet, but no underflow could be
HAMLIN.] TESTS IN 1902. 37

detected. No samples were collected. The underflow appeared to be 

along the gravel beds in the bottom of the wash.

The order of the strata, record of the wells, and the velocity measurements are shown in fig. 15.

Station 4 is on the east bank of Tujunga Wash, as shown in fig. 

12. A group of well points was here driven by hand, and a test made 

between 6£ feet and 14£ feet, where the direction of the underflow 

was S. 13° E., velocity 4£ feet per day. These wells were driven

Log of -well Underflow tests

Sand and gravel 14.' &"

rHgsr-^rl 22 6

6' 6

14:' 6

S 13° E

Vertical <scale 

10 20 30 feet

FIG. 16. Underflow tests at station 4.

deeper, and a test was made as at station 3, but no underflow could 

be detected. The order of the strata, record of the wells, and the 

velocity measurements are shown in fig. 16.

Station 5 is on Los Angeles River, near the road from Burbank 

to Cahuenga Pass, as shown in fig. 12. A group of well points was 

here driven by hand to a depth of 34£ feet, and a test made between 

26i feet and 34i feet, where the direction of the underflow was S. 40° 

E., velocity 48 feet per day. The water from this depth rose to a 

point 6 feet above the surface, and it is possible that the high velocity
38 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

was caused by leakage upward around the casing, which drew the 

charged water toward the well. Borings were made with a 2-inch 

auger at this station. The order of the strata, record of the wells, 

and the velocity measurements are shown in fig. 17.

Station 6 is in Tujunga Wash, south of the road from Burbank to Cahuenga Pass, as shown in fig. 12. This group of wells was driven to 

a depth of 16 feet, and a test made between 8 feet and 16 feet, where 

the underflow was N. 75° E., velocity 3£ feet per day. Borings were 

made with a 2-inch auger at this station. The order of the strata,

Log of well Underflow tests 

0'.______. o',

Silt and soil 4' 

Sand 2'

Silt? 13'

Silt and gravel

Silt 8'

Sand and gravel 3!e"

19'

23

34.6

26 6

«

4^

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O

p_(

OJ

s

h7

*H

1

I

o

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fl

?

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cS

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 r

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48.0'

Vertical scale 

10 20 30 feet

FIG. 17. Underflow tests at station 5.

record of the wells, and the velocity measurements are shown in 

fig. 18.

Station 7 is on the left bank of Los Angeles River, 1 mile south of 

Burbank, at the mouth of a broad sandy wash (see fig. 12). This 

group of wells was driven by hand to a depth of 8 feet, and a test 

made between 5 feet and 8 feet, where the direction of the underflow 

was due east, velocity 2£ feet per day. The underflow was away 

from the surface stream, and the slope of the water table was afterwards found by leveling to be in the direction indicated by the underflow. The order of the strata, record of the wells, and the velocity 

measurements are shown in fig. 19,
TESTS IN 1902. 39

Station 8 is on the left bank of Los Angeles River, 1 mile south of 

Bur bank, at the mouth of a sandy wash (see fig. 12). This group 

of wells was driven by hand to a depth of 9 feet, and a test made 

between 1 foot and 9 feet, where the underflow was found to be N. 

60° E., velocity QA feet der day. The order of the strata, record of 

the wells, and the direction of the underflow are shown in fig. 20.

These tests indicate that in general the underflow is in the direction 

of the greatest slope of the water table, although there are marked 

variations. No relation could be traced between the slope of the water 

table and the velocity of the underflow. The conclusion drawn from 

the few tests made was that the underflow tends to follow the most

Log of well Underflow tests

Sand 4'

Sand 1' 

Clay 2'

Sand,and gra*vel 9f 3.5'

VeTtlcal scale 

10 20 30 feet

FIG. 18. Underflow teats at station 6.

pervious strata, even if the extension of these beds varies considerably 

from the general slope of the water table. The maximum velocities 

are also found in such strata.

TESTS AT HURON STREET IN 19O3.

Extensive tests were made at the narrows of the Los Angeles River 

along Huron street, Los Angeles, Cal., in 1903 (see fig. 21). This 

locality will be spoken of as the Huron street section. It was selected 

for the following reasons:

(1) In 1896 the city drilled several test wells to bed rock, furnishing 

valuable data regarding the cross section of the pervious gravel beds.
40 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

(2) The city water commissioners are now driving a tunnel in bed rock 

beneath the river channel, beginning about half a mile south of Huron 

street, to extend entirely across the valley (see fig. 12). It is the 

intention in the future to drill wells through the pervious gravels and 

the bed rock above the tunnel and by perforating them draw off the 

percolating ground water through the tunnel and pump it to the city 

reservoirs. It was believed that the amount of water intercepted by 

the tunnel would give an approximate check on the accuracy of the 

ground-water measurements.

(3) The locality is near shops at which tools and machinery could be 

repaired, or manufactured if necessary.

Log o.f well LTn(jernow tests

0'

Coaise sand 8' East 2.5'

Vertical Scale 

10 20 3O feet

FIG. 19. Underflow tests at station 7.

The surface profile of Huron street and the cross section of the pervious gravels below are shown in fig. 22. The points marked station 

1 and stations 9 to 16 on both map and profile, figs. 21 a,nd 22, represent groups of test wells sunk by the United States Geological Survey. 

The points numbered 1-7 represent test wells sunk by the city of Los 

Angeles in 1896, arid the wells numbered 8-22 represent house wells in 

the vicinity. The underground cross section was platted from the 

information supplied by the various test wells and house wells in the 

vicinity. This representation of the underground conditions is necessarily incomplete, but no additional information is obtainable at present.
HAMLIN.] TESTS AT HURON STREET IN 1903. 41

Attention is called to the fact that the pervious beds of sand and 

gravel in this section (fig. 22) fall into two distinct groups, the lower 

and most westerly filling the bottom of the old channel of Los Angeles 

River. The easterly group is without doubt the thinning edge of the 

Arroyo Seco debris cone. This is proved by the fact that the coarse 

debris from the Arroyo Seco can be traced directly to this place. The 

terrace at the east end of the section is also composed of the same 

material.

The tests of underflow point to the conclusion outlined above; in the 

lower gravel bed the direction of the underflow is down the general

Log of well Underflow tests

Coarse, sand 9

N60°E 6.4:

Vertical scale 

10 20 30 feet

FIG. 20. Underflow tests at station 8.

trend of the river vallej^, as shown by the arrows on the map at stations 1 and 9-11; while at stations 12,13,14,15, and 16 the divergence 

from the trend of the valley is very marked in fact, at station 15 the 

flow at present is up Los Angeles River Valle}^.

It is probable, however, that this reversion of the flow is due to the 

rise of the water table in the Arroyo Seco debris cone. Normally the 

underflow is probably from Los Angeles River down the slope of the 

water table, as indicated by the broken contours in fig. 21, which show 

the slope of the water table in December, 1902, while the dotted contours show the slope in June, 1903, the change being due, as above 

noted, to the floods of the Arroyo Seco. The portions of the cross
42 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

section where measurable velocities were observed are diagonally 

cross hatched. The rest of the section appears to be practically 

impervious. 

The depths at which the various tests were made and the direction

FIG. 21. Map of Huron street and vicinity. Unbroken lines are surface contours showing topography; broken lines show form of water table in December, 1902; dotted lines show form of water 

table in June, 1903.

and velocity of the underflow measured are shown in figs. 23-30.

Attention is called to the general agreement in the slope of the 

water table and direction of the underflow.

FIG. 22. Huron street cross section.

STATIONS AND RESULTS.

The first test made was at station 9 (fig. 21), just above station 1. A 

group of well points was driven with a hand rig and tested between 

15 feet and 23 feet. The direction of the underflow was S. 30° E., 

parallel with the surface stream, velocity 77 feet per day. The well
EtAMLIN.] TESTS AT HURON STREET IN 1903. 43

points were then driven deeper and a test made between 22 feet and 

30 feet, where the direction of the underflow was S. 30° E., velocity 

20.8 feet per day. The order of the strata, record of the wells, and 

the velocity measurements are shown in fig. 23.

The ampere curve of the second test at this station is shown in fig. 

11, a. It illustrates what form of curve may be expected with high

Log of well Underflow tests

O'

ELne sand 20'

Fine gravel 6'

Medium gravel 2' 

Fine gravel 2'

Coarse sand. 4'

Medium gravel 4'

Quicksand 2' 

Q-.ravel 1'

Shale,

20'

28' 

30'

34

38'

40' 

41'

,.00,0000(7

rt, 

oOoOoOQ

0'

15'

22' 

23'

30'

irnber test of 

fc

1

2

Lon underflow o 

S

0

S 30° E

S30°E

of underlow ty 

day feet per 

1 3

^

77'

20.8'

Vertical scale 

1O 20 30 feet

Fig. 23. Underflow tests at station 9.

velocities and shows that observations at intervals of a few minutes 

must be taken to correctly delineate such a curve. This is an extreme 

case, however. A test well was sunk by the hydraulic-jetting method 

here and the record of the wells is based on the material washed out 

of the drivepipe. The pipes broke when it was attempted to drive 

them beyond about 30 feet and no deeper tests were made.
*-ps i

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^
HAMLIN.] TESTS AT HURON STREET IN 1903. 45

feet per day. It should be noted that the flow was probably through 

the stratum between 46 feet and 50 feet. Tests were afterwards 

made betweeen 33 feet and 41 feet, between 25 feet and 33 feet, and 

between 17 feet and 25 feet, but no underflow was detected. The

Log of well

Silt and sand 16'

Quicksand 25'

Silt and sand 11'

sand 3' 

Cemented sand 4'

Coarse sand. 17*

Quicksand is'

Fine sand 10'

16'

41

76

94

104.

0

Vertical scale 

10 2O

Underflow tests

17

25'

33'

41'

49'

55'

57'

63'

71'

79'

87'

95'

1 03'

Number 

of test

11

10

9

8

7

6

5

4

3

1

fc

Direction of underflo

__ ^

___

S 30° W

S30°E

South

S 30° E

 

___

 

<H £ >>

Velocity o 

underflow dafeet per 

___ _

___

20.0'

16.0'

10.0'

Jo.o'

 

*

___ .._ ^^

 __

30 feet

FIG. 25. Underflow tests at station 11.

material washed out of the drivepipe also indicated that the ground

was practically impervious. The order of the strata, record of the

wells, and the velocity measurements at this station are shown in fig. 24.

Station 11 is between the Southern Pacific Railroad and Avenue 20,
46 UNDEBFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

as shown in fig. 21. One well of this group was sunk with the handrig and the rest by the well-driving machinery, as described on page 

12. The first test was made between 95 feet and 103 feet, but the 

result was uncertain, the final conclusion being that there was no 

underflow at this depth. Other tests were made between 87 feet and 

95 feet, between 79 feet and 87 feet, between 71 feet and 79 feet, and 

between 63 feet and 71 feet, but no underflow could be detected. The 

water from 63 feet to 104 feet was heavily charged with sulphureted 

hydrogen. A test was then made between 55 feet and 63 feet.

Log of well Underflow tests 

0'

Sand and silt 21'' 

21' 

Granitic sand 17'

38' 

Coarse granitic sand 3' .*., 

Clay 1' 42'

Sand 12'

54' 

Hard yellow sand and clay 6' 

60'

Blue clay and sand 11' 

71'

0

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27' 

35'

if' 44

52'

53' 

61'

71

scale 

20

Number 

of test

8

7

4, 5 & 6

3

o

1

S 

S

30 feet

FIG. 26. Underflow tests at station 12.

The direction of the underflow was S. 30° E., velocity 10 feet per 

day. Another test was made between 49 feet and 57 feet. The direction of the underflow was due south and the velocity 10 feet per day. 

This was followed by a test between 41 feet and 49 feet, where the 

direction of the underflow was S. 30° E., velocity 16 feet per day. 

The next test was between 33 feet and 41 feet, where the direction of 

the underflow was S. 30° W., velocity 20 feet per day. Two more 

tests were made, one between 25 feet and 33 feet and another between 17 feet and 25 feet, but no underflow was detected. The order
HAMIJN.] TESTS AT HURON STREET IN 1903. 47

of the strata, record of the wells, and the velocity measurements at 

this station are shown in fig. 25. The wide divergence in the direction of the underflow at this station, amounting to 60°, indicates 

that the water follows the most open strata.

Station 12 is at the intersection of Huron street and Avenue 22, as 

shown in fig. 21. Tests were made between 63 feet and-71 feet, between 

53 feet and 61 feet, between 44 feet and 52 feet, and between 35 feet 

and 43 feet, but no underflow was detected. The next test was made 

between 27 feet and 35 feet, where the direction of the underflow was 

S. 15° W., velocity 48 feet per day, and also S. 75° W., velocity 48 

feet per day, the underflow here apparently being through two porous 

strata in which the directions of movement diverge 60°. The last

Log of "well o'

Soil 4' 4

Coarse sand 13'

IT'

Coarse sand and gravel 18'

OK'

Fine sand 1.5 36Yg"

Eine yellow sand 3.5' 4Q, 

Coarse sand 8 '

48' 

0

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24' 

30'

38'

46'

Vertical scale 

10 20

Number 

of test

3

2

1

30 fee

Undejrflojw tests

Fro. 27. Underflow tests at station 13.

test was made between 20 feet and 27 feet, where no underflow was 

detected. The order of the strata, record of the wells, and the velocity 

measurements are shown in fig. 26. Below 50 feet the water was 

impregnated with sulphureted-hydrogen gas.

Station 13 is at the corner of Huron street and Avenue 26, as shown 

in fig. 21. A test was made between 38 feet and 46 feet, where the 

direction of the underflow was S. 15° W., velocity 68 feet per day. 

The next test was between 30 feet and 38 feet, where the direction of 

the underflow was S. 15° W., and the velocity 20 feet per day. The 

last test was between 24 feet and 30 feet, where the direction of the 

underflow was S. 45° W., velocity 3.4 feet per day. The order of 

the strata, record of the wells, and the velocity measurements are 

shown in tig. 27. Attention is called to the westerly direction of the
48 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

underflow, due, without doubt, to the influence of the rising water 

table.

Station 14 is at the crossing of Huron street and River street, as 

shown in fig. 21. The first test was between 44 feet and 52 feet, where 

the direction of the underflow was S. 75° W., velocity 48 feet per 

day. The next test was between 36 feet and 44 feet, where the direction of the underflow was S. 75° W., velocity 32 feet per day. The

Log of -well Underflow tests

Soil

0'

Sand and gravel 16'

vi'-'-9Va-'-'-:Q:'^

'18'

(Jravel and bo-wlders 36'

Clay 8'

Hard yellow sand 4'

Clay and soft shale 16' 

Sandstone

54' 

62'

66'

36

52

43

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32.'

48.'

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Vertical Scale 

10 20 aofeetf

FIG. 28. Underflow tests at station 14.

top of the well screen being at about the level of the water plane 

before the rise due to the floods of the Arroyo Seco, it was decided to 

leave the pipes in the ground and test the direction and velocity of the 

underflow as the water table gradually falls. That it will fall is proved 

by the fact that the wells above are now lowering at about 1 foot per 

week. The order of the strata, record of the wells, and the velocity 

measurements are shown in fig. 28.
FAMLIN.] TESTS AT HURON STREET IN 1903. 49

Station 15 is at the eastern termination of Huron street, as shown 

i n fig. 21. The first test was made between 45 feet and 47 feet, but

Log of well

0

Soil

Gravel and bowlders 31'

Qlayand bowlders 5''

Coarse gravel 10'

35'

40'

50'

Clay and shale 12'

36'

40'

42' 

42'6" 

44'6"

47'

Underflow tests

«

5

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X 75° W

N 75° W

N 75° W

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11.0'

3.4'

3.5'

6.0'

"Vertical scale 

10 20 30feet>

FIG. 29. Underflow tests at station 15.

no underflow was detected. A test was then made between 42.5 feet 

and 44.5 feet, where the direction of the underflow was N. 75° W.,
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HAMLIN.] TESTS AT HURON STREET IN 1903. 51

the direction of the underflow was N. 75° W., velocity 11 feet per day. 

r""he order of the strata, record of the wells, and the velocity measurenents are shown in fig. 29.

Station 16 is north of Huron street, between Avenue 20 and Avenue 

'2, as shown in fig. 21. Tests were made between 52 feet and 56 feet 

rnd between 49 feet and 52 feet, but no underflow was detected. The 

r ext test was made between 45 feet and 49 feet, where the underi ow was S. 22° W., velocity 4 feet per day. Tests were then made 

1 otween 41 feet and 45 feet, between 37 feet and 41 feet, between 33 

feet and 37 feet, and between 29 feet and 33 feet, but no underflow was 

< etected. A test was then made between 25 feet and 29 feet, where the 

( irection of the underflow was S. 8° E., velocity 96 feet per day. 

r""he last test was made between 21 feet and 25 feet, but no underflow 

r^as noted here. The order of the strata, record of the wells, and the 

velocity measurements are shown in fig. 30.

Attention is directed to the probability of this well having penetrated both pervious areas in the Huron street cross section, as shown 

in fig. 22. All the ground tested here, except the two beds in which 

rnderflow was detected, seemed to be close-textured and practically 

impervious.

DISCHARGE AT HURON STREET.

Owing to the reversal in the normal direction of underflow, by the 

foods of the Arroyo Seco, it is not possible to estimate, except very 

FDproximately, the quantity of ground water passing the Huron street 

notion. The observed facts are here presented, from which engineers 

nay draw their own conclusions regarding the tests and value of the 

computations submitted.

The western and lower gravel bed, shown on the cross section, fig. 

'2, has a cross-sectional area of approximately 17,000 square feet, and 

the upper and eastern gravel bed has a cross-sectional area of about 

? 0,700 square feet below the water plane of 1896. These figures are 

1 ased on the results of the underflow tests, and on the assumption 

that all the cross section where flow was not detected has a velocity 

cf underflow of 1 foot per day. The outline of the pervious sections 

ims sketched from station to station.

The average of all the velocities observed in the western gravel bed 

n 20.6 feet per day, and the porosity is assumed to be 25 per cent. 

Using this data, the discharge from this portion of the section should 

lo 17,000X20.6X0.25 = 87,550 cubic feet per day. This discharge 

should be reduced by about 20 per cent to correct for the obliquity of 

low across the section, 87,550x0.8=70,040 cubic feet, or 524,000 

irallons per day, in round numbers.
52 UNDERFLOW TESTS IN LOS ANGELES BASIN. [NO. 112.

The average of all the velocities observed in the eastern gravel bee1 

is 30.9 feet per day. If it is assumed that under normal conditions 

the height of the water table is represented by the line marked 189P 

in fig. 22, the area of the cross section through which flow takes 

place will be 30,700 square feet. The slope of the water table was 

not radically different in 1896 (the assumed normal condition) from 

what it was in 1903, when the underflow tests were made, but the 

direction of the flow in the eastern end of the section was deflected 

nearly or quite 90 degrees from the normal. It is assumed that since 

the degree of slope of the water table at these two periods is approximately the same, the velocity of underflow was not radically different. 

Under normal conditions, the direction of flow makes an angle of 

about 30 degrees with the line of Huron street. The computed discharge has been multiplied by 0.50, the sine of 30 degrees, to correct 

for the obliquity in the direction of the flow. The porosity is hereassumed to be 25 per cent, as before. The discharge from this portior 

of the section should then be 30,700X30.9X0.25X0.5=118,578 cubic 

feet, or 889,000 gallons per day, in round numbers.

Although no flow was detected in the rest of the cross section, 

between the water table and bed rock, it can not be entirely impervious, and it is assumed that the average velocity is 1 foot per day. 

This is certainly a maximum, as many tests were continued long 

enough to detect as low a velocity as this.

If the average porosity is assumed to be 25 per cent as above, and 

the average direction of underflow is at an angle of 30 degrees witl 

Huron street, the discharge from this section should be 60,OOOXlX 

0.25X0.50=7,500 cubic feet per day, or 56,000 gallons, in round numbers.

The total computed discharge from the Huron street section will 

then be 196,118 cubic feet per day, or 2.27 cubic feet per second.

The city tunnel has now been driven 1,163 feet under the river bed, 

one-fourth mile below. This tunnel yields about 7 second-feet when 

pumped for a short time at intervals of a few days. The supply from 

the tunnel has so far been drawn from the water stored in the gravels 

in the immediate vicinity, pumping not having as yet been continued 

long enough to demonstrate what the gravel beds will yield.

COST OF TESTS AT HURON STREET.

The following table shows the average cost of testing underflow at 

Los Angeles, Cal., for a period of two months, using the well-drilling 

machinery and testing apparatus described in this report:
-'AMLIN.] SUMMARY. 53 

Cost of underflow tests at Huron street, Los Angeles, Gal, from May 14 to July 14, 1908.

"Vpll HrilW

'Oook ........................................

Observer. ....................................

Repairs ......................................

Total ..................................

Total 

expenses 

for 2 

months.

$150

100

70

150

120

40

30

8

150

818

Driving 

pipe.

$96

64

40

50

28

6

60

344

Pulling 

pipe.

$22

14

10

20

6

2

30

104

Testing.

$32

22

20

150

50

6

30

60

370

Pipe driven, 989 feet; cost per foot, $0.348.

Pipe pulled, 929 feet; cost per foot, $0.111.

Total number of underflow tests, 16; cost per test, $23.125.

Total average cost per test, including driving, pulling, etc., $51.125.

The well-drilling machinery described was constructed in Los 

Angeles from designs furnished the foundrymen and from machinery 

purchased at local supply houses.

Cost of well-drilling machinery.

Oost of drilling rig in Los Angeles ...................................... $870.00

'"Vo hundred linear feet of 3-inch, double, extra-heavy drive pipe, with 

taper-joint couplings, at $4 per foot................................... 800.00

Total........................................................... 1,670.00

SUMMARY.

The following suggestions are based on the experience gained during 

the work at Huron street and in the San Fernando Valley:

(1) The location of the section where it is proposed to test the underf ow should be carefully studied. It should be, if possible, in a straight 

stretch of the valley, and at some distance, either up or down, from 

large tributary streams.

(2) The form and slope of the water table should be ascertained and 

t e line of test stations placed most advantageously.

(3) In order to secure accurate results, the testing stations should 

Ve close together along the line of the section.

(4) The well screens should be short and the ground should be 

tested at each 2 to 4 feet in depth, down to bed rock when possible.
54 UNDERFLOW TESTS IN LOS ANQELES BASIN. [NO. 112.

(5) If possible, the porosity of the pervious beds should be 

determined.

(6) When making deep tests some form of drive pipe and screen 

such as described on the preceding pages should be used.

(7) Recording ampere meter and switch clocks should be used.

The discharge from a given section will undoubtedly be far less 

than anticipated, the popular tendency being to greatly overestimate 

the amount of underflow. Even if the results attained by this method 

of testing are not as accurate as desired, they are, nevertheless, of 

great value, as they enable investigators to compute, approximately, 

what could only be roughly estimated before.
INDEX.

Page. 

/ mpere curves, figure showing............. 28

/ mpere meter, description of.............. 23

plate showing.......................... 26

/ oparatus, plan of test wells and, figures

showing.............---..--.... 24,25

/ oparatus and methods, discussion of..... 11-32

Pattery, description of..................... 23-24

plate showing.......................... 26

P't, chopping, description of and figure

showing..-.---.......---..-.-.- 18

F'ock, buffer, description of and figure

showing........................ 17

P'ocks, description of...................... 19

Puffer block, description of and figure

showing........................ 17

Charging wells, method of................. 26-27

Charts, recording, plate showing......--... 24

Chopping bit, description of and figure

showing........................ 18

Clock, switch, description of .............. 22-23

plate showing.......................... 22

Cost of tests, table showing................ 53

"derrick, description of..................... 19

"discharge, computations of................ 29

"drilling rig, description of................. 13

drilling rig and machinery, plates showing. 14,16 

.">rive head, description of................. 16-17

figure showing......................... 17

r~>rivepipe, description of .................. 15-16

figure showing......................... 16

.">rive shoe, description of and figure showing ............................. 16

Driving well points, method of, plate showing............................. 12

"Electrodes, description of.................. 21-22

figure showing......................... 22

plate showing.......................... 20

"Engine, description of..................... 14

"ilbert, G. K., on test of sancffrom Arkansas River Valley............... 29

Ground water, definition of............... 9

flow of, method of measuring.......... 24-28

velocity of, method of determining..... 10-11 

."Tammer, description of................... 17-18

figure showing......................... 18

"Tand driving, sinking wells by............ 12

Head. See Drive head.

'Turon street, discharge at................. 51

map and cross section at............... 42

tests at................................. 39-64

' Tackscrews, description of................. 20

use of, plate showing................... 16

^ing, F. H., on pore space in sands........ 29

T^os Angeles River, basin of, description of. 32-34

basin of, map showing ................. 33

" f achine drilling, description of............ 13-14

Page. 

Meter, ampere, description of.............. 23

plate showing.......................... 26

Methods and apparatus, discussion of..... 11-32

Pipe. See Drivepipe.

Points, well, description of................. . 20

method of driving, plate showing...... 12

plate showing.......................... 12

Pump, description of....................... 15

Pumping, use of, in determination of velocity of underflow ............... 24-25

Recording charts, plate showing........... 24

Recording ampere meter, description of.... 23

plate showing.......................... 26

Rig, description of......................... 13

 plate showing.......................... 14

Rods, wash, description of................. 18

Shoe, drive, description of and figure showing... .......................... 16

Slichter, C. S., on motions of underground

waters.......................... 9,11

on porosity of quartz sand............. 29

Stose, G.W., test by....................... 29

Switch clock, description of................ 22-23

plate showing.......................... 22

Swivel, water, description of and figure

showing........................ 19

Table, water. See Water table.

Tests, description of....................... 34-54

Test wells, location of...................... 11-12

plan of apparatus and, figures showing. 24,25 

Testing apparatus, description of.......... 20-24

Underflow, amount of, computations of... 29 

method of measuring................... 24-28

velocity of, method of determining..... 10-11

Underflow tests, > methods and apparatus

used in......................... 11-32

Velocity of underflow, method of determining............................. 10-11

Wash rods, description of.................. 18

Water, ground. See Ground water. 

Water table, character of and fluctuations

in............................... 10

Water swivel, description of and figure

showing........................ 19

Well-drilling machinery, cost of............ 53

Well-drilling rig, description of............ 13

Well-drilling, rig and machinery for, plates

showing........................ 14,16

Well points, description of................. 20

method of driving, plate showing...... 12

plate showing.......................... 12

Wells test, location of..................... 11-12

Wire, description of........................ 21

Wiring, description o'f, in determination of

underflow...................... 25-26

55

o
LIBRARY CATALOGUE SLIPS.

[Mount each slip upon a separate card, placing the subject at the top of the 

second slip. The name of the series should not be repeated on the series 

card, but the additional numbers should be added, as received, to the first 

entry.]

Hamlin, Homer, 1864 

. . . Underflow tests in the drainage basin of Los 

Angeles River, by Homer Hamlin. Washington, Gov't 

print, off., 1905.

55 p., 11. illus., VII pi., diagrs. 23cm. (U. 8. Geological survey. Watersupply and irrigation paper no. 112.)

Subject series: O, Underground waters, 30.

1. Water, Underground California. 2. Los Angeles River.

Hamlin, Homer, 1864 

. . . Underflow tests in the drainage basin of Los 

Angeles River, by Homer Hamlin. Washington, Gov't 

print, off., 1905.

55 p., 11. illus., VII pi., diagrs. 23cm. (U. S. Geological survey. Watersupply and irrigation paper no. 112.)

Subject series: O, Undergroxind waters, 30.

1. Water, Underground California. 2. Los Angeles River.

U. S. Geological survey.

Water-supply and irrigation papers, 

no. 112. Hamlin, H. Underflow tests in the drainage 

basin of Los Angeles River. 1905.

U.S. Dept. of the Interior.

£

8 see also

U. S. Geological survey.