ISO 14686:2003

INTERNATIONAL ISO
STANDARD 14686
First edition
2003-07-15
Hydrometric determinations — Pumping
tests for water wells — Considerations
and guidelines for design, performance
and use
Déterminations hydrométriques — Essais de pompage pour puits
d'eau — Considérations et lignes directrices pour la conception,
l'exécution et l'utilisation
Reference number
©
ISO 2003
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

©  ISO 2003
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2003 — All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Terms and definitions. 1
3 Hydrogeological considerations . 5
4 Pre-test planning. 7
5 Pre-test observations . 20
6 Pumping test . 22
7 Special tests . 27
8 Post-test observations . 31
9 Presentation of information . 31
Annex A (informative) Well construction . 34
Annex B (informative) Groundwater conditions and aquifer states. 35
Annex C (informative) Water-level and discharge-measuring devices. 37
Annex D (informative) Well development. 48
Annex E (informative) Geophysical logging . 54
Annex F (informative) Examples of forms for data collection . 55
Bibliography . 57

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 14686 was prepared by Technical Committee ISO/TC 113, Hydrometric determinations, Subcommittee
SC 8, Ground water.
iv © ISO 2003 — All rights reserved

Introduction
Pumping tests are normally carried out to obtain data with which to:
a) assess the hydraulic behaviour of a well and so determine its ability to yield water, predict its performance
under different pumping regimes, select the most suitable pump for long-term use and give some
estimate of probable pumping costs;
b) determine the hydraulic properties of the aquifer or aquifers which yield water to the well; these properties
include the transmissivity and related hydraulic conductivities, storage coefficient, and the presence, type
and distance of any hydraulic boundaries; and
c) determine the effects of pumping upon neighbouring wells, watercourses or spring discharges.
A pumping test also provides a good opportunity to obtain information on water quality and its variation with
time and perhaps with discharge rate. These matters are not dealt with in detail in this International Standard.
When water is pumped from a well, the head in the well is lowered, creating a drawdown or head loss and
setting up a localized hydraulic gradient that causes water to flow to the well from the surrounding aquifer. The
head in the aquifer is also reduced and the effect spreads outwards from the well. A cone of depression of the
potentiometric surface is thus formed around the well and the shape and the manner of expansion of this cone
depend on the pumping rate and on the hydraulic properties of the aquifer. By recording the changes in the
position of the potentiometric surface in observation wells located around the pumping well, it is possible to
monitor the growth of the cone of depression and determine these hydraulic characteristics. The form of the
cone of depression immediately around the well will generally be modified because additional head losses are
incurred as the water crosses the well face. The drawdown may be considered to consist of two components:
a) head loss through the aquifer; and
b) head loss in the well.
Consequently, there are two test objectives: an understanding of the characteristics of the well and those of
the aquifer.
A test may be performed to serve either of these two main objectives. If they are satisfied, it may be said that
the hydraulic regime of the well and aquifer has been evaluated. However, it needs to be understood that
other information, particularly about other factors affecting recharge, will be required to predict the long-term
effects of abstraction.
It needs to be recognized that there are inherent difficulties involved in carrying out a pumping test, e.g.
making many physical measurements. In part, these arise from the tendency of the measurement process or
equipment to change the quantity being measured. For example, the drilling of boreholes to investigate the
hydraulic regime of an aquifer may disturb that hydraulic regime by providing vertical communication between
aquifer levels containing water at different heads. A second difficulty involves sampling. Only rarely will a cone
of depression be circular and symmetrical; the relatively few observation boreholes that are usually available
in effect provide a limited number of sampling points with which to determine the form of the cone. It is
important that these limitations and difficulties are kept clearly in mind when designing and analysing a
pumping test and, in particular, when using the results.
Figure 1 indicates the normal sequence of events in a pumping test.
Figure 1 — Typical pumping-test procedure

vi © ISO 2003 — All rights reserved

INTERNATIONAL STANDARD ISO 14686:2003(E)

Hydrometric determinations — Pumping tests for water wells —
Considerations and guidelines for design, performance and use
1 Scope
This International Standard describes the factors to be considered and the measurements to be made when
designing and performing a pumping test, in addition to a set of guidelines for field practice to take account of
the diversity of objectives, aquifers, groundwater conditions, available technology and legal contexts. The
standard specifies the fundamental components required of any pumping test. It also indicates how they may
be varied to take account of particular local conditions. It deals with the usual types of pumping test carried out
for water-supply purposes, in which water is abstracted from the entire screened, perforated or unlined
interval(s) of a well.
Interpretation of the data collected during a pumping test is referred to in this International Standard only in a
general way. For full details of the analysis and interpretation of test data, reference should be made to
specialized texts. Examples of such texts are included in a selected bibliography.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
abstraction
removal of water from a borehole or well
2.2
access tube
pipe inserted into a well to permit installation of instruments, and safeguarding them from touching or
becoming entangled with the pump or other equipment in the well
2.3
aquifer
lithological unit, group of lithological units, or part of a lithological unit containing sufficient saturated
permeable material to yield significant quantities of water to wells, boreholes or springs
2.4
aquifer loss
head loss at a pumped or overflowing well associated with groundwater flow through the aquifer to the well
face
2.5
aquifer properties
properties of an aquifer that determine its hydraulic behaviour and its response to abstraction
2.6
borehole
a hole, usually vertical, bored to determine ground conditions, for extraction of water or measurement of
groundwater level
2.7
casing
tubular retaining structure, which is installed in a drilled borehole or excavated well, to maintain the borehole
opening
NOTE Plain casing prevents the entry of water.
2.8
column pipe
that part of the rising main within the well
2.9
cone of depression
that portion of the potentiometric surface that is perceptibly lowered as a result of abstraction of groundwater
from a well
2.10
confining bed
bed or body of impermeable material stratigraphically adjacent to an aquifer and restricting or reducing natural
flow of groundwater to or from the aquifer
2.11
discharge
volumetric flow rate
2.12
drawdown
reduction in static head within the aquifer resulting from abstraction
2.13
filter pack
granular material introduced into a borehole between the aquifer and a screen or perforated lining to prevent
or control the movement of particles from the aquifer into the well
2.14
flow, steady
flow in which parameters such as velocity, pressure, density and temperature do not vary sufficiently with time
to affect the required accuracy of measurement
2.15
flow, uniform
flow in which the magnitude and direction of flow at a given moment are constant with respect to distance
2.16
foot valve
non-return valve fitted at the bottom of a suction pipe of a pump
2.17
groundwater
water within the saturated zone
2.18
hydraulic conductivity
volume of water at the existing kinematic viscosity that will move in unit time under a unit hydraulic gradient
through a unit area measured perpendicular to the direction of flow
NOTE This definition assumes an isotropic medium in which the pores are completely filled with water.
2 © ISO 2003 — All rights reserved

2.19
hydraulic gradient
change in static head per unit of distance in a given direction
2.20
hydrogeology
study of subsurface water in its geological context
2.21
impermeable material
material that does not permit water to move through it at perceptible rates under the hydraulic gradients
normally present
2.22
incompetent stratum
stratum unable to stand without support
2.23
isotropic
having the same properties in all directions
2.24
lining
tube or wall used to support the sides of a well, and sometimes to prevent the entry of water
2.25
lining tube
preformed tube used as the lining for a well
NOTE See also casing (2.7) and screen (2.39)
2.26
lithology
physical character and mineralogical composition that give rise to the appearance and properties of a rock
2.27
observation well
well used for observing groundwater head or quality
2.28
overflowing well
well from whic
...