The Auger Hole Method - W. Van Beers 1983

8/21/2019 The Auger Hole Method - W. Van Beers 1983

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THE A U G E R HOLE METHOD

A

field measurem ent of

the hydraulic conductivity of soil

below the water tab le

W .

F.

J

van

BEERS


2/32

,

. .

I .

. .

,


3/32

I

,

T A B L E O F CONTENTS

page

1 8

I ,

S E C T I O N

1

4

Introduction '

1

S E C T I O N

2 5 The. drilling of the holes

I

S E C T I O N

3

7

The removal of the water from the hole

S E C T I O N

4

7

Measurement o f the rate o f rise

i

I (

I

7

. 4.1 Interval and range,

I

1 9 4.2

Equipment

10

4.3 Procedure

S E C T I O N 5 12 Computing the hydraulic conductivity ,'

from the data of measurement

12

5.1 Grap h s

13 I 5.2 Formulae ,

14

5.3

Examples

I

S E C T I O N 6

17

,Auger-holes in a layered soil

S E C T I O N 7

19 Possible errors and variations

t


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1 . I N T R O D U C T I O N .:

The auger-hole method is a rapid, simple and reliable mFthqd for measuring hydraulic

conductivity of soil below a water table. It is mostly used i n connection with the design

of drain age systems in waterlogged land ánd'in canal seepage investigations.

The method, or ig inated by DISERENSl934), was improved by HOOGHOUDT1936) a n d

later by K I R K H A M1945, 1948), VAN

BAVEL

1948), E R N S T1950). JOHNSON1952) a n d

K I R K H A M1955).

T h e general principle is very simple: a h is bored int o the soil to a certain depth below

the water table. When equilibrium is reached

with

the surround ing groundwater, a part

of the water in the hole is removed. The water seeps into the hole again, and the rate

at which t he water rises in the hole is measured and then converted by a suitable formula

to the hydraulic condu ctivity'(k(f0r the soil.

The auger-hole method gives the average permeability of the soil layers extending from

the water table to a small distance (a few decimetres) below the bottom of the hole.

I f

there is an impermeable layer at the bottom of the hole, the value of k is governed by

the soil layers above this impermeable layer. The radiu? pf the column of soil of which

the permeability is measured is about 30-50cm:

Th e use of this metho d is limited tosareas with a high ground water table (a t least du rin g

'

. a

1

,*

,


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2.

T H E D R I L L I N G , O F T H E H O L E S ,

f

2 .

* I

I

This h,as to be do ne wi th the, n im um dis turbance to the soil .

T h e required

deprli

o f t he h o d i p e n d s on .;he natu re, thickness an d sequ ence of

sol1

layers

i n

the a re a under inves tiga tion and on the depth a t which

i t I S

required

to

de t e r -

mine hydraul ic conduct ivi ty. If the soi l i s homogeneous

to

a grea t depth, a practical

dri l l ing depth wil l be about

60

to 70

c.m below the water table, or preferably somewhat

more than the ' l ength

of

the bai ler .

In many cases, h owev er, t h e prrofile con sists

o f

IH O o r m o r e

luyers

having

an

ap- '

preciable difference in permeabili ty.

I t

wil l often be desirable to-know the permeabi l i ty

of each layer. When uslng

HOOGHOUDT'S

o r m u l a

(1940) or

s imi la r formu lae for des ign-

' .

' *

ing a t ile drai nag e system

i t

is necessary to kno w the k-fac tor of the soil ab ov e an d be low

the drains. If the water table l ies wel l wi thin the upper layer the hydraul ic conduct ivi ty

of each layer can be de te rmined. In ' th i s case

i t

will be necessary

to

work wi th

t ~ v o r

i n o re / / d e s a t d i f fe rent dept l is . T h e bot tom of the sha llow hole should be a t l eas t

IÖ-I5

c m

above the lower layer and - for pract ical reasons - 20 cm be low the water t able . The

deep hole , which for t i le dra in age des ign p urposes normal ly has a dep th of 2 meters, is

dri l led f i rs t and the various soi l layers are examined and described. The depth of t he

shallow hole is determin ed o n th e basis of this profile investigation.

] f a very high hyd raul ic conduct ivi ty can be expected and the soi l is com parat ively ho m o-


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Despite of the fact that the tested soil column' associated

with

the auger-hole meth od, is

much larger than an undisturbed core' sample taken for laboratory tests

(I400

I

1,

REEVEnd

K I R K H AM ,

951),

i t will

be necessaiy to repeat'thè permeabiliiy determinations

a t seve ra l places, because of the differences which always occur in permeability of soils

classified as one' soil type. For detailed tile-drainage investigations one determination

to every two acres

will

usually be sufficient.

One man can dri ll about

,10-20

sets of holes a day . The auger used

in

the Netherlands

(a n open blade type, see

fig.

1)

is very suitable for use in'wet clay

soils.

The closed type

"

posthole auger commonly used in the

U S A

is

excellent in dry

soils

but

is

less suit

for wet clay soils (Soil Survey Manual,

U . S . D . A . ,

1951,

page

67).

. r ,

, , I

I

9

F i b .

2.

Diagram

of

me tho d followed

in

deter

I (

t h e hydraulic conductivity by the auger

,hole procedure .

b ,

.

, I

I .


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S

= dcpth of the imperme,tblc hy er l?clou, thc bottom

of

the hole.

3. T H E R E M O V A L O F W A T E R F R O M T H E H O L E .

I A

*

, *

This can start when equil ibrium with the surrounding groundwater is at tained and the

depth of theswater table has been recorded. Usually it will take 10-30 minutes to refill

the hole

i n

a moderately permeable soil

( k = 1

m/day), som e hou rs in a slowly permeable

soil (k = 0:lO m/day).l)

The seeping of the groundwater into the hole will also re-open soil pores in the wall

of

the hole that may have been closed by the auger.

I f

an open blade-type of auger is

used, i t is unnecessary to remQve the water from the ho le 2

or

3 t imes for this purpose. .

The most effective way of removing the water is with a bailer, viz.: a thin-walled pipe of

about 50 to 60 cm in length, with a diameter of about 2 cm less than the diameter of

I

the auger-hole an d with a valve at the botto m . This bailer can also be úsedain combination'

with a perforated tube fo r making a hole in the unstable sandy soils.

The water level in the hole sho uld be reduced 20 to 40 cm (yo

=

20-40 cm, see

fig.

2). On e

or two bailings a re required - depending on the length and diameter of the bailer used.

'


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If a n electric device is used, a fixed Ay is chosen. If a'float with a measuring tape is used.

either Ay or At can be measured at regular intervals. However, several stopwatches a,re

' .

. I

necessary fo r measuring with a fixed Ay. whereas

if

mea suring is don e at regular intervals

of

time it is sufficient to use one watch with a good second hand. The latter method of

measuring is usually followed in the Netherlands.

The time interval (At) chosen depends on the permeability of thecsoil and is usually

5-10-15 o r 30 seco nds . A At is usually observed to be corresponding to a Ay of about

one cm. For soils with a very low *permeability

(k -10.01,

r

=

4; Ay/At

=

hO.01 to

0.02 mm per second), a Ay of about 5 mm an d , a At of some minutes is

'a

good combi-

nation.

If

the soil. has a very high permeability (k = IO; by/At

=

about 10 mm per se-

cond) an interval of 5 seconds is observed. It will be clear that for soils with a high

permeability Ay greatly exceeds 1 cm an d only one or two reliable readingscan be taken.)

Tw o men are needed for a n interval

of

5

seconds, whereas

I O

second interials can easily

be read and recorded by one man.

Due.consideration should be given to the fact that i t is not~pe rmissible o.continue the

measurementsfor

too

long since the funnel-shaped drawdown of the water table which

develops ab ou t the t op o f the hole a s the hole fills+would become too large. This wo uld'

result

i n

a decrease of the,actual H-value and consequently in a decrease of the rate of

rise, and

if

the k-factor were computed from the original H-value this would give too<

low as va lue for: k (see example No . 3).


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per second for a moderately permeable soil ( k

=

Im/day), 0.01-0.02 m m f o r a very

slowly

permeable soil

( k

=

0.01)

an d som e cent imetres per second for

a

highly permeable

soil

k - - I O ) .

I t .wil l be clear ' that in the case

of

a highly permeable and moderately per-

meable soil we shou ld s tar t the measu remen ts a s soo n a s possible af ter bail ing, whereas

in

the case' of

a

slowly p ermea ble soil there is

no

reason to hurry . A calculat ion of the

time available for reliable measurements is given i n Appendix I

4.2

EQUIPMENT

The equipment as originally used by

HOOGHOUDT

was fair ly heavy and complicated

(see

HOOGHOUDT,1936).

Convenient electr ic equipment has been developed in the

U S A

and is also used in Austral ia

(MAASLAND,

957).

In

the Nether l ands conven ien t and

simple equipm ent was developed by the la te Professor

M .

F. Visser.

Fig. 3.


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. .

I . I .

The la tes t s impl i f ica t ion is tha t the rule r and the pointe r 1 iave .been omi t ted and the

{ t anda rd somewha t modi ti ed i n 'o rde r

to

prevent difficultie\

on

windy day<

(fig. 4) .

T h e

5tandai-d is pressed into the~ soi l p

to

a ce r t a in mark 40 tha t the reading\ c'in be takcn at

a fixed distance (40 cm ) above grou nd leve l.

Figure 5 shows the

$et

used fo r the m ca4urcmcnt

of

the hydraul ic conductivity . com ple te

with

a n

auger wi th extens ion a n d -a perfora ted meta l tu be .

*

,


11/32

t

he standard i s returned

in

its former position and .the float placed on the surface of

6 About 5 readings are taken at regillar intervals of time. Since i t sometimes happens

that the \teel tape or float tends to stick to the wall of the cavity

i t

is recommended

to

lap the steel tap: regularly. All readings, including igroundwater level and depth of the

hole, are taken at the conductor of the tape on the standard

(40

cm above groundlevel).

7.

The depth of the hole

is

measured by use,of the bailer,o r auger.

Th e rate of rise is ?o m es measured imm ediately afte: the drill ing of the hole This me thod

IS

t ime-

Th e level

of

the groundwater can usual ly be measured the same day, but

i f all

layers have

a

very low

permeabil ity the grou ndw ater level shou ld be mea sured

o n

the fol lowing day.

However, i t should be noted that this method

of

measur ing the ra te

of

rise immediately afte; drilling

can only be used in slowly permeable to mod erately,slowly permeable soi ls with

little

water in the hole

after drill ing (relajively large y',), a s the admissible am ou nt o f retu rn f low dur ing the t ime of dr i ll ing a nd

measuring should be l imited to ab ou t

25

percent of the am ou nt of water reniovyd by dri l ling. M oreove r ,

the drill ing ha s

to

be carried out with

an

open type of posthole auger , as this type gives

less

puddl ing

alon g the wall of the cavi ty an d the dr i ll ing proceeds m ore rapidly t ha n with the closed type of p osthole

ater. The reading then has

to

be started as soon as possible.

,

'

~

,

1 9

,

I

saving and also has, th an tag e that

no

bailer

is

needed.

I

.


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5.

C O M P U T I N G ~ T H E Y D R A U L I C

C O N D U C T I V I T Y

F R O M T H E

D A T A

O F

T H E M E A S U R E M E N T S ’

1 1

t

f .

5.1. G R A P H S

The type of graph developed by BOUMANS1953; VISSER, 1954) is co m ho nl y used in th e

Netherlands.

Recently othe r graphs as developed by WES TERHO FERNST,WESTERHOF,953) have a lso

been used ‘in combination with a special m ethod of recording t h e readings for each

interval

of

time. Using a n ad ditio na l mechanism on the sta nd ard , a pencil point is pressed

at each inteTval of time

on

a slip ofpaper attached to the steel tape rule. This piece of

paper is placed on a graph then and ( in combination with a second graph) the k-factor

can be com puted. How ever, these graph’s’ have only been prepared .fo r

r =

4.5 and

S > & H . . I .

I _

’ .

ERNST1950) prepared graphs for

r

= 4 arid “r =’6 , both for S

‘=‘O

n d , S > :H. hese

graphs are the result.of relaxation constructions.

T he relation between the k-factor and the rate of rise

(Ay/At)

can be expressed as follows:

. .

I

( 1 )

I


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In general it can be said.that the soil layers at a depth greater than 10-15 cm below the

bottom of the hole have little influence on the rate of rise of the water in the hole, and

the graph

S

>

H an be used.

The graphs prepared by ERNST an also be used for

an

auger-hole with

a

radius other

than 4

or 6

cm . Augers are often used, which have a ra dius of

5

cm or a 4-inch diameter.

Graphs

3 and 4, included in this bulletin, have therefore been prepared for r

=

5 c m .

This has been done by converting the graphs for

r

4 cm.

l

Th e graphs are used as follow s:

C is read from the diagrams as a function of y and

H .

H is found at the abcissa in cm.

Using the line with the proper y value.

C

can be read as the ord inate (see also example

in graph 1). I

5.2.

FORMULAE

A formula is not often used for computing the hydraulic conductivity since convenient

grap hs are available. Moreover, unlike the formulae th e graphs may be used for a wider

range of y and H values and they are more accurate. Th e difference may a m ou nt to 20 per-'

cent. For the sake of completeness the formulae, 'which can be used when no graph is

available, will be given here.

, .


14/32

L

In

this formu la

k

is expressed in m/24 h our s. All oth er quantities are in cm

or

in sec.

k

=

hydraulic conductivity.

H

=

depth of hole below the groundwater table.

y = distance between groundwater level and the average level ofbthe water in the hole

' '

r

=

radius of auger-hole.

S = depth of the impermeable layer below the bottom of the hole or the layer, which

has

a

permeability

of

abo ut one tenth

or

less of th e perm eability of the layers above.

Equation (2) represents an empirically derived approximate expression of the results of

a number of relaxation constructions. Hence this formula does not show the exact

relationship that should theoretically exist between the different quantities, although the

value of k will be sufficiently accurate (m axim um er ro r: 20 7 ; ) f the following conditions

a re met :

r

> 3

and

<

7 c m ;

H >,20, a n d < 200 c m ;

y > 0.2 H ;

S > H ;

,

for the time interval At.

.

I +

A y 5 1 i 4 Y O .

Eq uatio n (2 ) can also be written i n an oth er form , which facilitates calculations:


15/32

Example

N o .

4 shows that the k-factor computed will be too low if the measurements

are cont inued fo r

too

long (Ay

>

1/4

y o )

o r

if

too

long

a

period elaps es between bailing

1 yo.:

I

*

Locàtion:

*

D ' =I' 40 D

= 200

W '

=

I 4

W -

1 4

H =

126

H ==

126

t

~

Yt'

AYt

O 145.2

o

144.0

20 142.8'

141.7

0

40 140.6

1.2

I z

1 . 1

1 1

1 . 1

D a te

:

Technician:

I

I

r = 4

k estm.

=

m/day

S = > H k calc. = 0.66 m/day

yo ==

yo - W '

=

145.2

-

I14

=

31.2

C 4 y t

=

5.6:

Y

= yo

-

Yn =

y

=

yo

-

;Ay'-= 31.92 - 2.8

=

28.4

\

1 2 6 '

C

=

6 .0 ( read f rom G raph

1 )

.

y

=

28.4


16/32

When the difference is much larger, e.g. the At-values being: 27-44-56-71,, then

large openings

in

the.soil profile are occurring (cracks, holes caused

by roots,

wood

or

nnimals).

I n

t h a t

case measuring should be repeated in an'other place.

.

. *

D

=

165

D = 125

W' = 100 W = 60

H =

65

H =

65

'Yt - - t

At

r, = 4 K

(estm.)

= (-1

m.

/day,

s

=

>

H K

(calc.)

=

OS7 m./day

-

y

= y ' - w ' = 126- 100 =

26

]

c

=

11,2

H = 65

h y

4

400

At 84 84

x = 0,048

_

_


17/32

,EXAMPLEo 4.

~ _ _ _ _ _ - -

Y1

Ayt

--

r - 4

S > i H graph

I

H

=

35

- 1.5

AylAt

= 5.8160

-

1.5

- 1.4

y =

27.4

C --

17.8

k ==

1.75

I

I

30 3

15 28.8

30 27.3

45

25.9

-

60

90

105

20

I35

I50

I65

180

I95

210

225

240

7>

24.5

23.2 -

21.9

20.7 - 1

1.3

-

1 . 1

19.6

18.6 -

' 1

17.6

-

16.7 -

- 0.9

15.8

, '

15.0 -

:::

0.7

\

12.7 -

- 0.8

.............................

AylAt

4.9160

y

=

22.0

c = 20.2

k

= 1.65

............................

AylAt

=: '3.8160

y =- 17.7

C

=-:

23.2

' k

r 1.47

h y j A t = 2.9160

. . . . . . . . . . . . . . . . . . .

y

= 14.3

C

= 27.5

k =:

1.33

. .

' <


18/32

I

shallow hole should be at least

10-15

cm abo ve the lower layer. I n most cases the dee p

hole is m ade first in orde r to locate the boun dary of the two layers

(fig.

7).

Fig. 7.

I

I

I

I

* *

I

t

I

8 %

'

If we call the hydraulic conductivity of the upper layer k, an d the lower layer k,, then

.

th e ra te of rise in the deep hole is:

I

Ay' It

Co

--

-

k,

AY'

-

kl k2 k2 At'


19/32

AYI

k, == -

c

t

C

- - - - k

OAt’

6.3 :.‘0.26 - 1.5 1.64- 1.5

0.14

- . - -

-

0.62

r

o‘22

-

- -

-

6.3

1

1.62 -

I

3 . 9

1

- --

co

1

7. P O S S I B L E E R R O R S

AND V A R I A T I O N S

The following possible errors have to be taken into account.

a . The maximum er ror in the graphs is estimated at 5 percent.

b .

The error caused by a wrong measurement of H and y is inversely proportional to

the magnitude of H and y.

For. instance:. a

1

cm error in the measurement of

H

causes a 2 percent error in the

k-value if H

=

50 and a I percent error if H = 100. The same is true of y. This

shows that there is no need to measure

H

and

y

with an accuracy of millimetres.

-

c.

If

a

wrong figure is used for the radius r the order of magnitude of the error is usually

about 20 percent for half a centimetre difference

in

radius, or

20

percent for the dif-


20/32

all over the area, than bij measuring and calculating this factor with great accuracy in a

particular hole.

The determination of hydraulic conductivity of the soil in a certain area should always

be combin ed with a soil survey. There often is a close correlation between the soil

characteristics as seen in the field and the k-factor of the soil, but this correlation can

only be established

o n

a regional basis. 8

<

, +

c i 3

R A N G E

F H Y D R A U L I C

CONDUCTIVITY

VALUES I N

THE ,NETHERLANDS

I N

m/day

(

HOOGHOUDT,952)

8

Sands: 0.1 for fine sands to 30 in coarse sands;

V

Clays: 0.01 o more than

30.

Some clay soils have better permeability than coarse sandy

- soils;


21/32

I

T I M E

A V A I L A B L E F OR R E L I A B L E ' M E A S U R E M E N T S ( A y

<

1/4y,),

for k = 1 m / d a y a n d r = 4 c m

I

yb:in cm.

I 15

20

25 30 40 50 60 70 80

90

100 120 140

Ay =

114

yo:

-

H =

30:

H = 50:

H ' = 75:

H

=

100:

H

= 150:

3.75

5

6.25 7.5

10 12.5 15

17.5 20 22.5 25. 30 35 .,

,

time

in seconds

109 117

131

146

83 88 90 105 I

47

50

53 56 60 63 68 73 79 1

a 60 63 66 72 78 87 .

37 39 41 43 46 48 50 52 57 63

Example

of

calculat ion:

H

=

75

y

= 20

]

c

=

12.

For k

=

I :

At = b y x C .

=

C AY

A t *

I

Ay or permissible range of measurement = 1/4 x

20

c m = 5 cm.

A t

=

Ay x C =

5

s

12

seconds =

60

seconds.

For the case tha t H

=

75 a n d y

=

20 c m a n d k

=

Im/day, there are 60 seconds available


22/32

tab le sand y so i ls i t is necessary to use

a

perfora ted tube. Th e auger is used

u p to

the pdin t where the hole becomes uns table . Th e per fora ted tube

is

the; lowered in to the

ole. By moving up an d down the bai le r - which has

a

valve a t th e bot tom - he mixture

rid a nd water en ters the ,bailer and the tube can be pushed dow nwards .

1 ,

' I

SCR1,PTION OF

T H E

PERFORA

1 .

1

2 mm thick, pe r fo ra t ions abou t 4 m m a p a r t -a n d a b o u t

O.

a

8

c m

i n

outer d iam eter fo 'r a hole 'with a d

i n

diameter . The

e;er

of

8 cm, and ' 1 hetre

I '

t h

a riveted ring:

t h e t u b e o u t a o f he" borehole a k ind o f dra wh oo k is useful . Cam s for hol-

hoo k a re s ecu redqto the to p of the screen tube.

$ .

( I

, *

. . .

I


23/32

R E F E R E N C E S ' .

BAVEL,

.

H. M.

VAN

AND

D.

K I R K H A M :

948:

Field measurements,

.

of

soil

permeabji i ty .using auger

BOUMANS,

.

H. 953: Het bepalen van de drainafstand met behulp

van

de Boorgiiten, methode: Land-,

BOUWER, . ET AL . 1955: Drainage'research methods'on stony soils. Airic. Eng . , pp. 592.

DISERENS,. 1934: Beitrag zur' Bestim mun g der D urchliissigkeit d es Bodens in natiirlicheri Bod eniage -

ERNST,

L.

F.

1 950: A

new form&

for

'the c&ukition

of

the p,ermeabijity factor with the auger hqle

1 .

. .

holes. Proc. Soil. Sc. Soc. Am.. pp. 90-96.

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. .

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..

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method . T .N.O. ,Groninge n 1950. Translated from the Dutch by H . Bouwer, Coriiell Univ.'Ithacn.

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N.Y. 1955.

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ERNST,L.

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a n d

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J . WESTERHOF.

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H ~ H Ò U D T ,. ,B. 1936: Bepaling van den doorladtfactor vn'n de n 'gron d'm et behulp vin"po,mpproeven,

HCJOCHOUDT,

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JOHNSON, .

P.,

R . ' K .

FREVERT.

n d

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D. EVANS.

1952:

Sinlplitied procedure for the measurement .

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KIRKHAM;D.

1945:

Proposed methods

for

field .nieasurenien ts of.perniea bility

of

soil

below the water-.

cation au drainage aux Pays-Bas. Assoc. Intern. Hydr.., , . Publ. 41. Symposia Dirrcy (DiJon . 1956).

. . .

_

, +

(z.g.

boorgatenmethode). Verslag Landbouwk. Onderzoek

42.

pp.

449-541.

Verslag Landbouwk. Onderzoek 46.

, ,

'

.

. . .

, I .

I .

.

'

. I .

I 1 . , .

I

; .

I

computation of soil permeab,ility below the wati:r-table. Ägris. Eng., pp: 283-286.

,,

'

..

. 1 ..

,

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1 .

table. Proc. Soil. Sc. Soc. Am., pp.

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L I S T O F A V A I L A B L E P U B L I C A T I O N S , S E P T E M B E R 1979. I i <

P U B L I C A T I O N S

( 1 I )

(13)

(14)

(15)

.

(16)

P. J. Dieleman,

ed,Reclamation

of

salt affected

soils in

Iruq.

1977, 175 pp . 3rd edition.

DG 16.-. ' '

L. J . Pons, and.1.

S.

Zonneveld. Soil ripeningand sqilclassification. 1975. 128 pp. D G 12.-.

G.

A. W. van de

Goor

and G. Zijlstra. Irrigation requirements or double cropping of lowland

rice

in

Malaya. 68 pp . 1977, 2nd editio n. D G 7.-.

D. B. W. .M. van Dusseldorp. Planning of service.centres in rural areas of development

countries. 1971. 159 pp. DG 13.-.

Drainage principles and applications. Vols. I/lV , 1455 pp. DG 90.-.

Vol. I : Intro duc tory subjects, 2nd edition 1979,241 pages, D G 20.-. .

Vol. 111

:

Surveys an d investigation, 1974, 364 pages, D G 30.-.

' . '

Vol: IV.: Design and management

of

dra inag e systems: 19 74,4 76 pages, D G 40.-:.

Vol. I : M ateria s prelim inar es, 1977, 257 pages, DG 20.-.

Vol. I1

:

Qeo rias del drenaje agricola y de la esco rrentia; 1977, 402 pages, D G . 30.-:

Vol. IV : Diseño y manejo de los sistemas de drenaje, )97 8, 547 pages, D G 40.-.

(17) Lizndevaluation fo r ruralpurposes. 1973. 116 pp. D G l-I.-.

(19) M.

G.

Bos and

J .

Nugteren.

On

rrigation efficiencies.

1978. 140 pp. revised e dition . D G 14.-.

(20) M.

G:

Bos, ed. Discharge measurement structures, 464 pp. 1978, 2nd editio n. D G 40.-.

(21) N. 'A. de Ridder an d A. Erez. Optimum use of water resou&: 1977. 250 pp . DG'25.-.

.

(22) FAO. A fra me wo rkf or land evaluation. 1977. 87 pp. D G 8.-.

(23) K. J. Beek.

Land evaluation f o r agricultural development.

1978. 336 pp. D G 30.-.

(24) J. Ma rtinez Beltran.

Drainage and reclamation of salt-affected

soils .'1978. 321 pp. D G 30..

(25) ,J: Wesseljng.

Ed. Proc.. Int. Drainage Workshop

May 1978 W ageningen, 730 pp..DG 60.-.

F.ieldbook for 1,and and wa ter m anagem ent experts, 1 972,'672 pp: DG 68.1.

'

~, , I

' -

, I

ol. 11: Theories o f field drain age and watershed runoff, 2 nd e ditio n 1979, 374 pages, DG 30.-.

(16/S)

Principios

y

aplicaciones del drenaje,

Vols. I/lV, 1600 pp. D G 90.-.

,

Vo l.'IIl: Estudios e investigaciones, 1978, 395 pages, D G 30.'.

. I ,

,

. .

' '

'

. *

..

I

. _ , . .

B U L L E T I N S

(1)

W.

F.

J .

van Beers.

The u w e r hole method.

1979.5th edition. 23

pp.

D G

8.-.

.

(1 1)

G. P. K rusem an, and". Ä. de Ridder. Analysis and evalwition ofpumping test data. 1979.

GRAPH 1


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I

C

1111 III

.u

'

H =m

r=4cm

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H

E

AUGER HOLE METHOD;

tute for Land Reclamation and Improvement, Wageningen, The Netherlands.

1958.


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GRAPH 2


27/32

r = 4 c m

s = o

Bulletin

No

1

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I

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AUGER HOLE

METHOD;

International Inst tute for Land Reclamation and Improvement, Wageningen, The Netherlands, 1958.


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for ia nd Reclamation and Improvement, Wageningen, The Netherlands,

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GRAPH 4

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31/32

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No

1 THE A U GER HOLE METHOD;

International

I

stitute for Land Reclamation and Improvement, Wageningen, The Netherlands. 1958.

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The Auger Hole Method - W. Van Beers 1983

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