EN ISO 22282-4:2021

Geotechnical investigation and testing - Geohydraulic testing - Part 4: Pumping tests (ISO 22282-4:2021)

This document establishes requirements for pumping tests as part of geotechnical investigation service in accordance with EN 1997-1 and EN 1997-2.
This document applies to pumping tests performed on aquifers whose permeability is such that pumping from a well can create a lowering of the piezometric head within hours or days depending on the ground conditions and the purpose. It covers pumping tests carried out in soils and rock.
The tests concerned by this document are those intended for evaluating the hydrodynamic parameters of an aquifer and well parameters, such as:
—     permeability of the aquifer,
—     radius of influence of pumping,
—     pumping rate of a well,
—     response of drawdown in an aquifer during pumping,
—     skin effect,
—     well storage,
—     response of recovery in an aquifer after pumping.

Geotechnische Erkundung und Untersuchung - Geohydraulische Versuche - Teil 4: Pumpversuche (ISO 22282-4:2021)

Dieses Dokument stellt Anforderungen an Pumpversuche als Teil der geotechnischen Erkundung nach EN 1997 1 und EN 1997 2 auf.
Dieses Dokument gilt für Pumpversuche in Grundwasserleitern, deren Durchlässigkeit so ist, dass das Abpumpen aus einem Brunnen — in Abhängigkeit von den Bedingungen des Baugrunds und dem Zweck — zu einer Absenkung der piezometrischen Höhe innerhalb von Stunden oder Tagen führen kann. Das Dokument behandelt Pumpversuche in Locker  und Felsgestein.
Bei den durch dieses Dokument abgedeckten Versuchen handelt es sich um diejenigen, die zur Auswertung der hydrodynamischen Parameter eines Grundwasserleiters und von Brunnenparametern vorgesehen sind, z. B.:
—   allgemeiner Durchlässigkeitsbeiwert des Grundwasserleiters;
—   Einflussradius des Pumpens;
—   Förderrate für einen Brunnen;
—   Auswirkung in Bezug auf die Absenkung in einem Grundwasserleiter während des Pumpens;
—   Skin Faktor;
—   Brunnenspeicherkoeffizient;
—   Auswirkung in Bezug auf die Wiederherstellung in einem Grundwasserleiter nach dem Pumpen.

Reconnaissance et essais géotechniques - Essais géohydrauliques - Partie 4: Essais de pompage (ISO 22282-4:2021)

Ce document traite des exigences relatives aux essais de pompage réalisés dans le cadre d’une mission de reconnaissance géotechnique conformément à l’EN 1997-1 et l’EN 1997-2.
Ce document s’applique aux essais de pompage réalisés sur des formations aquifères dont la perméabilité est telle que le pompage à partir d’un puits peut créer un rabattement du niveau piézométrique en quelques heures ou jours selon les conditions de terrain et l’objectif. Il traite des essais de pompage réalisés dans les sols et les roches.
Les essais concernés par ce document sont ceux destinés à évaluer les paramètres hydrodynamiques d’une formation aquifère et les paramètres du puits, tels que
—    la perméabilité de la formation aquifère,
—    le rayon d’influence du pompage,
—    le débit de pompage d’un puits,
—    la réponse en termes de rabattement dans une formation aquifère pendant le pompage,
—    l’effet pariétal,
—    l’emmagasinement du puits,
—    la réponse en termes de remontée dans une formation aquifère après pompage.

Geotehnično preiskovanje in preskušanje - Hidrogeološke preiskave - 4. del: Črpalni preskus (ISO 22282-4:2021)

General Information

• Status: Published
• Publication Date: 06-Apr-2021
• Withdrawal Date: 30-Oct-2021
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: CEN/TC 341 - Geotechnical Investigation and Testing
• Drafting Committee: CEN/TC 341 - Geotechnical Investigation and Testing
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 07-Apr-2021
• Completion Date: 07-Apr-2021
• Ref Project: SIST EN ISO 22282-4:2021 - Geotechnical investigation and testing - Geohydraulic testing - Part 4: Pumping tests (ISO 22282-4:2021)

Relations

• Replaces: EN ISO 22282-4:2012 - Geotechnical investigation and testing - Geohydraulic testing - Part 4: Pumping tests (ISO 22282-4:2012)
• Effective Date: 14-Apr-2021

Overview

EN ISO 22282-4:2021 - "Geotechnical investigation and testing - Geohydraulic testing - Part 4: Pumping tests" - sets out requirements for conducting pumping tests as part of geotechnical investigation services in accordance with EN 1997-1 and EN 1997-2. It applies to pumping tests on aquifers (soils and rock) whose permeability allows a measurable lowering of the piezometric head within hours or days. The standard is the ISO/CEN reference for planning, executing, recording and reporting pumping (well) tests used to characterise groundwater flow and well performance.

Key topics and requirements

• Test scope and objectives: Evaluating hydrodynamic and well parameters such as permeability, radius of influence, pumping rate, drawdown behaviour, skin effect, well storage and recovery response.
• Equipment and instrumentation: Guidance on pumps, discharge measurement, level gauges and piezometers (referencing ISO 18674-4 for piezometer measurement).
• Test planning and preparation: Determining suitable discharge rates, arranging discharge disposal, and preparing the test and monitoring wells.
• Execution procedures: Stepwise procedures for pre-pumping monitoring, preliminary pumping, main pumping phase, post-pumping recovery monitoring, handling interruptions and uncertainty assessment.
• Data handling and reporting: Requirements for field records, installation logs, measured values and a structured test report (including example record formats in annexes).
• Applicability: Tests covered are for aquifers where pumping effects are measurable within hours to days; applies to both soils and rock.
• Normative references: Links to related ISO standards (e.g., ISO 22282-1, ISO 22475-1, ISO 14688-1) for general rules, sampling and classification.

Applications

Pumping tests under EN ISO 22282-4:2021 are used to:

• Determine aquifer transmissivity and hydraulic conductivity for foundation design and geotechnical risk assessments.
• Design and size dewatering systems for excavations, tunnels and underground works.
• Assess well performance and optimize well construction or rehabilitation.
• Support groundwater resource assessments, contaminant transport studies and hydrological modelling.
• Inform slope stability, settlement and long-term groundwater control measures required by EN 1997 design processes.

Who should use this standard

• Geotechnical and hydrogeological engineers
• Engineering consultancies and site investigation contractors
• Well designers, groundwater modellers and environmental consultants
• Public authorities and clients specifying site investigation work under EN 1997

Related standards

• ISO 22282-1 (General rules for geohydraulic testing)
• ISO 18674-4 (Piezometer measurement)
• ISO 22475-1 (Sampling and groundwater measurements)
• EN 1997-1 / EN 1997-2 (Geotechnical design standards)

Keywords: EN ISO 22282-4:2021, pumping tests, geohydraulic testing, geotechnical investigation, aquifer permeability, piezometric head, well testing, hydrodynamic parameters.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2021
Nadomešča:
SIST EN ISO 22282-4:2012
Geotehnično preiskovanje in preskušanje - Hidrogeološke preiskave - 4. del:
Črpalni preskus (ISO 22282-4:2021)
Geotechnical investigation and testing - Geohydraulic testing - Part 4: Pumping tests
(ISO 22282-4:2021)
Geotechnische Erkundung und Untersuchung - Geohydraulische Versuche - Teil 4:
Pumpversuche (ISO 22282-4:2021)
Reconnaissance et essais géotechniques - Essais géohydrauliques - Partie 4: Essais de
pompage (ISO 22282-4:2021)
Ta slovenski standard je istoveten z: EN ISO 22282-4:2021
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 22282-4
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2021
EUROPÄISCHE NORM
ICS 93.020 Supersedes EN ISO 22282-4:2012
English Version
Geotechnical investigation and testing - Geohydraulic
testing - Part 4: Pumping tests (ISO 22282-4:2021)
Reconnaissance et essais géotechniques - Essais Geotechnische Erkundung und Untersuchung -
géohydrauliques - Partie 4: Essais de pompage (ISO Geohydraulische Versuche - Teil 4: Pumpversuche (ISO
22282-4:2021) 22282-4:2021)
This European Standard was approved by CEN on 10 December 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22282-4:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 22282-4:2021) has been prepared by Technical Committee ISO/TC 182
"Geotechnics" in collaboration with Technical Committee CEN/TC 341 “Geotechnical Investigation and
Testing” the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2021, and conflicting national standards shall
be withdrawn at the latest by October 2021.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 22282-4:2012.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 22282-4:2021 has been approved by CEN as EN ISO 22282-4:2021 without any
modification.
INTERNATIONAL ISO
STANDARD 22282-4
Second edition
2021-03
Geotechnical investigation and
testing — Geohydraulic testing —
Part 4:
Pumping tests
Reconnaissance et essais géotechniques — Essais géohydrauliques —
Partie 4: Essais de pompage
Reference number
ISO 22282-4:2021(E)
©
ISO 2021
ISO 22282-4:2021(E)
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

ISO 22282-4:2021(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 2
3.1 Terms and definitions . 2
3.2 Symbols . 2
4 Equipment . 2
5 Test procedure . 3
5.1 Test preparation . 3
5.1.1 General. 3
5.1.2 Determining the discharge rate for the pumping test . 3
5.2 Arranging the disposal of discharge water . 3
5.3 Executing and equipping the well . 4
5.3.1 Design of the test well . 4
5.3.2 Installation procedure . . . 6
5.3.3 Preparation of the well . 6
5.4 Executing and equipping the piezometers . . 6
5.4.1 Installation procedure . . . 6
5.4.2 Preparation of piezometers . 6
5.5 Execution of the test . 7
5.5.1 General. 7
5.5.2 Pre-pumping monitoring . 7
5.5.3 Preliminary pumping phase. 7
5.5.4 Pumping test . . . 7
5.5.5 Post-pumping monitoring . 8
5.6 Uncertainty of measurement . 8
5.7 Interruptions in pumping . 9
5.8 Decommissioning . 9
6 Test results . 9
7 Reports. 9
7.1 Field report . 9
7.1.1 General. 9
7.1.2 Installation record .10
7.1.3 Record of measured values and test results .10
7.2 Test report .11
Annex A (informative) Record of measured values and test results of the pumping test —
Example .12
Annex B (informative) Determining the pumping test discharge .15
Annex C (informative) Interpretation of the pumping test results .19
Bibliography .27
ISO 22282-4:2021(E)
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 182, Geotechnics, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 341, Geotechnical
investigation and testing, in accordance with the Agreement on technical cooperation between ISO and
CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 22282-4:2012), which has been
technically revised.
The main changes compared to the previous edition are as follows:
— editorial changes;
— correction of formulae.
A list of all parts in the ISO 22282 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved

ISO 22282-4:2021(E)
Introduction
General rules on the planning and execution of geohydraulic field tests are covered by ISO 22282-1.
A pumping test consists in principle of:
— drawing down the piezometric surface of the groundwater by pumping from a well (the test well);
— measuring the pumped discharge and the water level in the test well and piezometers, before, during
and after pumping, as a function of time.
INTERNATIONAL STANDARD ISO 22282-4:2021(E)
Geotechnical investigation and testing — Geohydraulic
testing —
Part 4:
Pumping tests
1 Scope
This document establishes requirements for pumping tests as part of geotechnical investigation service
in accordance with EN 1997-1 and EN 1997-2.
This document applies to pumping tests performed on aquifers whose permeability is such that
pumping from a well can create a lowering of the piezometric head within hours or days depending on
the ground conditions and the purpose. It covers pumping tests carried out in soils and rock.
The tests concerned by this document are those intended for evaluating the hydrodynamic parameters
of an aquifer and well parameters, such as:
— permeability of the aquifer,
— radius of influence of pumping,
— pumping rate of a well,
— response of drawdown in an aquifer during pumping,
— skin effect,
— well storage,
— response of recovery in an aquifer after pumping.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 14688-1, Geotechnical investigation and testing — Identification and classification of soil — Part 1:
Identification and description
ISO 14689, Geotechnical investigation and testing — Identification, description and classification of rock
ISO 18674-4, Geotechnical investigation and testing — Geotechnical monitoring by field instrumentation —
Part 4: Measurement of pore water pressure: Piezometers
ISO 22282-1, Geotechnical investigation and testing — Geohydraulic testing — Part 1: General rules
ISO 22475-1, Geotechnical investigation and testing — Sampling methods and groundwater
measurements — Part 1: Technical principles for the sampling of soil, rock and groundwater
ISO 22282-4:2021(E)
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 22282-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.2 Symbols
Symbol Designation Unit
D drilled diameter of the well m
d thickness of the aquifer m
L wetted length of screen of the perforated pipe placed in the well m
Q flow rate m /s
Q discharge rate, assessed pumping discharge at the end of the well preparation m /s
d
Q discharge rate of the pumping test m /s
e
S storage coefficient —
T transmissivity m /s
t time s
v velocity —
a slope of the line that characterizes the drawdown in the well —
b ordinate at the origin of the line that characterizes the drawdown in the well —
c conventional drawdown unit of the preliminary pump discharge —
d size which may be interpolated from the grading curve, of the square sieve mesh of side d —
N
for which the weight percent of undersize is equal to N percent
e distance between the bottom of the well and the surface of the unconfined groundwater at m
rest in an aquifer
Δh drawdown of the water level in the well m
Δh' drawdown of the water level in the well after 2 h m
Δh drawdown of the water level in the well, set during the preliminary test and not to be m
f
exceeded
Δh maximum drawdown of the water level in the well during the pumping test m
max
4 Equipment
The following equipment and instruments shall be used to conduct a pumping test:
a) a test well and piezometers in accordance with ISO 18674-4;
b) a pump and associated pipework capable of pumping from the test well; the pumps shall be equipped
with a suitably long discharge pipe so that the water from the pump is discharged sufficiently far
away so that it does not affect the test area; the capacity of the pump shall be sufficient to extract
from the well a discharge at least equal to that corresponding to that estimated to achieve the
maximum planned drawdown;
NOTE Pumping tests are commonly carried out using electric submersible pumps, installed within the
test well. However, depending on conditions, pumping tests can also be carried out using suction pumps
located at the surface, airlift equipment, or special dewatering equipment such as well points or eductors.
2 © ISO 2021 – All rights reserved

ISO 22282-4:2021(E)
c) a system for regulating and measuring the discharge rate (m /s); devices for measuring the
discharge rate shall be suitably calibrated and shall be accurate for a range of flow rates anticipated
during the test;
d) a system for measuring the water level in the test well and piezometers; the turbulence in the test
well caused by pumping shall be considered; the devices shall be capable of measuring water levels
over the range of drawdowns anticipated during the test;
e) a time measuring and/or recording device, reading in seconds.
5 Test procedure
5.1 Test preparation
5.1.1 General
When preparing a pumping test, there are a number of things to investigate and consider in advance,
such as:
— basic information on the ground and groundwater conditions according to ISO 22282-1;
— the required drawdown and/or the required discharge rate during the test;
— the discharge point for the pumped water and its location relative to the test well;
— the duration of the test.
5.1.2 Determining the discharge rate for the pumping test
The discharge rate Q shall be estimated to ensure that the test well can yield sufficient water, to allow
d
a pump of appropriate capacity to be selected, and to ensure that the discharge can be accepted at the
agreed disposal point.
The discharge rate can be estimated by one or more of the following methods:
— based on the purpose of the test and experience of local conditions;
— by theoretical assessment of the well capacity, according to the method described in Annex B;
— by analysis of information from the preliminary pumping phase, according to the method described
in Annex B.
5.2 Arranging the disposal of discharge water
It is presupposed that the disposal of discharge water is in accordance with relevant rules and
regulations.
If the discharge water is not disposed of via an engineered sewer network, it shall be disposed of at
sufficient distance from the test well that it will not have a significant impact on the observed pattern
of groundwater lowering.
ISO 22282-4:2021(E)
5.3 Executing and equipping the well
5.3.1 Design of the test well
The test well shall be designed to satisfy the following criteria (see Figure 1):
— of sufficient depth to penetrate below the groundwater level in the strata of interest; if the test well
does not fully penetrate the aquifer, it shall penetrate the saturated part of the aquifer to a depth of
at least 25 times the well screen diameter with a minimum of 3 m;
— of sufficient drilled diameter to accommodate the necessary filter materials and well screen of
sufficient diameter to accommodate pumping equipment of adequate capacity to achieve the
required discharge rate;
— with sufficient length and capacity of well screen to ensure that the required discharge rate can be
achieved;
— to have appropriate filter material to ensure that the discharge water contains an acceptably low
sediment content to avoid the risk of pump damage and ground settlement as a result of the removal
of fine particles from the soil; where the well is constructed in a stable rock, it may be possible to
construct a test well without the need for filter material.
The filter material shall be a highly permeable granular material of closely controlled particle size and
be formed of grains of inert minerals in relation to the aquifer groundwater chemistry (e.g. quartz,
feldspar). In granular soils, the filter's grading curve shall satisfy the double inequality:
5 d ≤ d ≤ 5 d
15 soil 15 filter 85 soil
where d designates the characteristic size of the filter or of the ground in place, such that the mass of
N
the soil fraction passing through a sieve with a square mesh of side d represents N % of the total mass
of material.
In fine grained soils or where the well screen is equipped with a geotextile mesh designed to act as a
filter, the filter material’s purpose is to backfill the annular space between the outside of the well screen
and the borehole wall. In those circumstances the filter media should be highly permeable coarse sand
or fine gravel, with a permeability coefficient at least 100 times that of the soil or rock being tested.
The thickness of the annular space for the filter pack shall be at least 50 mm. The inner diameter of the
test well shall be selected according to the purpose.
4 © ISO 2021 – All rights reserved

ISO 22282-4:2021(E)
Key
1 well screen (slotted tube) 7 plain tube
2 filter material (filter pack) 8 device for measuring the water level
3 submersible pump 9 base of the screen
4 borehole casing L filter length
5 tube for measuring the water level D drilled diameter of the well
6 sealing plug
Figure 1 — Test well equipped for a pumping test — Example
ISO 22282-4:2021(E)
5.3.2 Installation procedure
The test well shall be constructed in a similar way to piezometers in accordance with ISO 18674-4.
Great care shall be taken when installing the well materials. Particular attention shall be paid to the
following:
— The well screen shall be lowered into the borehole to the specified level and shall be installed
centrally in the well, with the top and bottom of the screen located at the design level. Care shall
be taken that the joints of the screen and casing do not leak, and that the screen and casing are
installed vertically and straight.
— If necessary, filter material shall be inserted in the annular space between the screen and the temporary
casing (or borehole wall). The filter material shall be placed progressively in stages to reduce the risk
of a blockage in the annular space. The filter material should be placed via a tremie pipe.
— If necessary, a sealing plug of low permeability material (such as bentonite) shall be created in the
annular space between the borehole wall and the well casing immediately above the filter material.
The purpose of the sealing plug is to prevent infiltration of surface water, or water from other
aquifers, into the well screen.
5.3.3 Preparation of the well
Prior to the pumping test the well shall be developed to increase the permeability of the soil around the
shell by washing, and to remove any drilling residues and mobile soil particles that could be entrained
by the water flow into the well. Such particles could clog the filter and damage the test pump.
Development shall be carried out by means of pumping. Possible methods include airlifting or pumping
using a robust pump that is not damaged by the presence of particles in the discharge water. If airlift
pumping is used, care shall be taken to avoid injecting air into the ground, as air bubbles in the ground
can affect the permeability.
Other methods for well development may be used in combination with pumping, including:
— jetting with water inside the well screen;
— surging or swabbing inside the well screen to induce water flow into and out of the well;
— chemical treatment (e.g. use of acids in carbonate rocks).
5.4 Executing and equipping the piezometers
5.4.1 Installation procedure
Piezometers shall be installed in accordance with ISO 18674-4.
The piezometer tubes shall be installed at such a depth that the influence of the test well can be observed
and recorded adequately. Where possible, the piezometer closest to the test well shall be located at the
same depth as the bottom of the test well.
5.4.2 Preparation of piezometers
Before commencement of the test, piezometers shall be cleaned in accordance with ISO 18674-4. The
water level in the piezometers shall be measured for a period before and after the test in order to find
any natural variations in the groundwater level. Their response time shall be checked by watching the
water rise in the piezometer tube. The period of monitoring depends on the nature of the aquifer and
the purpose of the pumping test.
6 © ISO 2021 – All rights reserved
...