Generic Code of Practice for Cost Effective Boreholes · drilling, borehole development, completion...
Transcript of Generic Code of Practice for Cost Effective Boreholes · drilling, borehole development, completion...
Generic Code of Practice for
Cost Effective Boreholes Consultation Draft 2
Rural Water Supply Network Code of Practice
Cost-Effective Boreholes
June 2010
1
Code of Practice for
Cost-Effective Boreholes
Executive Summary
The Generic Code of Practice for Cost-Effective Boreholes aims
to raise the level of professionalism in rural water supply pro-
grammes that include water well drilling so that:
Policies and practices that bring about cost-effective bore-
hole provision are adhered to and fully supported.
Country systems and procedures are developed and used,
with strong institutions.
Performance of the drilling sector is routinely monitored
and evaluated and reported on in a transparent manner.
The document sets out four general and nine specific principles
for borehole drilling covering: community selection, planning
and coordination, operation & maintenance, groundwater re-
sources, drilling enterprises, procurement, contract manage-
ment, supervision, siting, drilling technology, borehole design
and construction, well development, pumping test, water quality
analysis, data and databases as well as monitoring and evalua-
tion.
The document provides a framework for the analysis of the
strengths and weaknesses of existing procedures. It can be used
to develop a national protocol for cost-effective borehole provi-
sion and by international organisations to determine whether
they are working in accordance with best international practices.
Table of Contents
Executive Summary 1
1 Introduction 2
2 General Issues 3
3 Principles for Cost-Effective Boreholes 4
Principle 1 Professional Drilling Enterprises and Consultants 4
Principle 2 Procurement 5
Principle 3 Contract Management, Supervision and Payment 6
Principle 4 Borehole Siting 7
Principle 5 Construction Method 8
Principle 6 Borehole Design and Construction 9
Principle 7 Data and Information 10
Principle 8 Database and Record Keeping 11
Principle 9 Monitoring and Evaluation 11
Annex 1 Bills of Quantities 12
Annex 2 Categorisation of Risk and Payment Structures 13
Annex 3: Sample borehole designs 14
Annex 4. Suggested Format for Borehole Completion Record18
Definitions For the purpose of the Code of Practice for Cost-Effective Bore-
holes, the key terms are defined as follows:
Borehole - a hole which is drilled in the ground and lined for
the abstraction of groundwater.
Borehole design - choosing the depth, diameter and lining
materials of the borehole and the drilling technique to be used.
Borehole development - the act of cleaning a borehole by
flushing or other means until the water from the hole is clean
and free of fine materials.
Borehole siting - the selection of the optimal location of the
boreholes by either hydrogeological and/or geophysical means
to ensure the design yield.
Community Selection Process - the process by which commu-
nities are selected to benefit a borehole fitted with pump.
Data - all facts about a borehole collected before and during,
drilling, borehole development, completion and pumping test.
Drilling contractor is a private company engaged in the drilling
of boreholes for water supply boreholes.
Drilling technology - the method of construction and equip-
ment used in making the borehole.
Monitoring - the periodical checking of the functionality of
boreholes, pumps and pad and community management of the
water source.
Operation and maintenance - running and repairing a bore-
hole, pumps and pads and so that the pump works at all times
throughout its designed life and the general area of the well is
kept clean.
Planning at Community level – a pre-project assessment of
existing water and socioeconomic situation of the community to
determine sustainable water facility.
Procurement - the process of selecting a drilling contractor or
hydrogeological consultant to undertake a particular service or
construction.
Quality Control - ensuring that the pumps and spare parts
supplied adhere to the specifications.
2
Code of Practice for Cost-Effective Boreholes
1 Introduction
In accordance with the Paris Declaration on Aid Effectiveness
external support organisations and donors should increasingly
support national, Government led water and sanitation pro-
grammes. Unfortunately, the fragmentation of donor support in
the past, coupled with weak Government institutions mean that
national standards and procedures with respect to water well
drilling are often lacking. Alternatively, if standards and proce-
dures have been defined, then adherence and enforcement
tends to be poor. In many developing countries, concerns have
been raised about the varying construction quality of drilled
water wells as well as apparently high costs.
The term “cost-effective” means optimum value for money in-
vested over the long term. In order for drilled water wells (sub-
sequently referred to as boreholes) to be cost-effective they
need to be appropriately specified, properly sited and drilled
using suitable equipment. Where the private sector is used,
competent procurement and contract management procedures
need to be followed. Drillers, as well as supervisors need to op-
erate in a professional manner to ensure adequate construction
quality.
Boreholes are drilled to function for their intended lifespan (in
the range of 10 to 30 years). Thus, the lowest cost borehole is
not always the most cost-effective, particularly if construction
quality is compromised to save money. Cheap drilling can lead
to premature failure of the borehole or contamination of the
water supply. Boreholes which are abandoned by the users due
to poor construction quality are clearly not cost effective.
This document sets out a Generic Code of Practice for Cost-
effective Boreholes (COP) based on best international practice. It
recommends procedures to be followed, defines minimum
standards and sets out reporting requirements with respect to
the provision of boreholes.
The purpose of the COP is to raise the level of professionalism
of borehole drilling so that:
Policies and practices that bring about cost-effective bore-
hole provision are adhered to and fully supported.
Country systems and procedures are developed and used,
with strong institutions.
Performance of the drilling sector is routinely monitored
and evaluated and reported on in a transparent manner.
The COP provides a menu of ideas to be considered by practi-
tioners and policy makers as they try to improve the cost-
effectiveness of borehole provision. It provides a systematic
framework to identify in-country, or organisational strengths
and weaknesses with respect to the provision of boreholes. Es-
sentially it provides a lens through which to examine the poli-
cies, standards and practices for borehole drilling in a particular
country, or for a specific programme.
The intention is that the COP is used as a basis for the devel-
opment of a national protocol1 for cost-effective borehole pro-
vision and that international organisations use it to determine
whether they are working in accordance with best international
practices.
Analysis of existing strategies, procedures, guidelines and ca-
pacity in a particular country or organisation against the COP
enables key areas for improvement, donor support, knowledge
exchange and technical assistance to be identified.
It is envisaged that national governments together with their
major development partners will develop a country-specific
protocol1 which takes into account the guidance set out in this
COP. Ideally the protocol should be adhered to by all sector
players as they plan and implement water supply programmes
that include borehole drilling. They would thus all work accord-
ing to common and well accepted procedures.
This document sets out four general issues, which relate to all
water supply development interventions, and nine specific prin-
ciples for borehole drilling (Box 1). These principles are critical in
order to achieve cost-effective borehole provision. For each
country (and more locally) some of the principles will be more
critical than others. Thus country-specific protocols will differ
accordingly.
In terms of context, geology varies widely, as do approaches to
improving rural water supply. In some countries emergency
situations prevail, others are in transition or reconstruction and
some are implementing long-term development interventions.
In some countries water supply programmes are undertaken
through numerous projects while others implement a few pro-
grammes or even a single national programme. The capacity of
the public sector as well as the maturity and professionalism of
the private sector also varies considerably.
Determining the importance of each principle and how to
address it is the responsibility of in-country stakeholders;
primarily national Government in collaboration with its devel-
opment partners. Country assessments and studies can enable
the strengths as well as critical areas for improvement to be
identified. The development of a national protocol1 requires a
partnership between national Government through the lead
Ministry for water supply, and other stakeholders in country.
There is need for extensive dialogue and consensus-building to
prioritise the principles and determine how to address the key
issues. The process of developing a national protocol1 and en-
suring that it is adhered to is not a one-off event but is an on-
going process spanning several years.
1 In some countries the protocol is referred to as a strategy or a
code of conduct.
3
Code of Practice for
Cost-Effective Boreholes
Box 1 Summary of Code of Practice for Cost-effective Boreholes
General Issues Principles for Cost Effective Boreholes
1. Community Selection
2. Planning and Coordination
3. Operation & Maintenance
4. Groundwater Resources
1. Professional Drilling Enterprises
2. Procurement
3. Contract Management, Supervision and Payment
4. Borehole Siting
5. Construction Method
6. Borehole Design and Construction
7. Data and Information
8. Database and Record Keeping
9. Monitoring and Evaluation
Full adherence to the COP set out in this document requires
strong national systems as well as public and private institutions
with sufficient capacity in terms of finance, personnel, skills and
equipment. Such systems and capacity can only be built over
time and efforts are required to ensure that they are main-
tained. Existing capacities need to be considered when develop-
ing a country-specific protocol. Where these capacities are
weak, Government and other water sector stakeholders should
prepare an action plan for addressing them over a realistic time
period.
Chapter 2 of this document summarises the general issues for
rural water supply programmes. The nine principles for Cost
Effective Boreholes are set out in chapter 3, each with a more
detailed explanation. The annexes of this document provide
relevant guidance materials and references.
2 General Issues
The issues set out below relate directly to other national strate-
gies for rural water supply, decentralisation and water resources
management. Although emergency situations may require
short-term solutions with immediate results, the subsequent
transition to a development situation should also be considered.
General Issue 1. Community Selection
The process of community selection for improved water
supplies is well-defined and transparent. In countries where
there is some form of decentralisation, this process is led by
local government.
National systems for prioritisation and community selection
(e.g. demand responsive; pro-poor; equitable access) are ad-
hered to by all agencies involved in rural water supplies.
General Issue 2. Planning and Coordination
Planning and coordination of water supply infrastructure
improvements is undertaken by the lowest appropriate
level of Government (e.g. District or Ward).
All donors, NGOs and other Government institutions must in-
form local Government and consult with them from the plan-
ning of investments through to infrastructure development.
Local Government should develop a workplan which coordi-
nates the social components (i.e. sensitisation, mobilisation and
training) with borehole siting and construction works. Potential
contractors must be informed of the workplan. Efforts should be
made to consolidate the plans and tenders for borehole con-
struction by water, education and health departments at local
level. Multi-year development plans at local government level
can form the basis for multi-year contracts.
General Issue 3. Operation and Maintenance
The long term operation and maintenance requirements for
the full lifetime of the technology should be fully consid-
ered during the planning stage.
At a bare minimum, there is need for a national operation and
maintenance strategy which ensures that:
water users, caretakers, mechanics, suppliers and local Gov-
ernment have the right equipment and skills and are aware
of their roles and responsibilities in relation to others;
a clear process of community contribution or full payment
for construction is adhered to by all stakeholders working in
a particular area/district/country;
collection of user fees for maintenance (and possibly re-
placement) is adhered to by all stakeholders working in a
particular area;
there is a reliable supply chain for spare parts;
a robust and adequately financed system of follow-on sup-
port to water users is in place.
In addition, it is essential that a quality control mechanism for
handpumps and spare parts is in place and adhered to. This
should include pre-shipment inspection, certification as well as
consignee end inspection.
If water users do not fulfil their obligations with respect to op-
eration and maintenance then re-training and improvement of
management should be undertaken rather than new construc-
tion.
General Issue 4. Groundwater Resources
Measures are taken to manage and monitor groundwater
resources and protect vulnerable resources from over-
exploitation.
Water quality should be checked for bacteriological and chemi-
cal contamination in accordance with national guidelines (e.g.
arsenic, nitrate, fluoride, iron, manganese). Users should be
aware of the risks associated with consumption of water from
highly contaminated sources. Specific follow-up of vulnerable
resources should be undertaken.
4
Code of Practice for Cost-Effective Boreholes
3 Principles for Cost-Effective Boreholes
Each of the following nine sections comprises an overall prin-
ciple (in bold), followed by sub-principles and further details.
It is anticipated that the national protocol will follow this over-
all structure, modifying principles as appropriate and even
adding or removing specific principles where necessary.
Principle 1 Professional Drilling Enterprises and
Consultants
Borehole construction and supervision is undertaken by
professional and competent organisations which adhere to
national standards and are regulated by the public sector.
Construction of boreholes and installation of pumps should
normally be undertaken by local private sector firms rather
than by Government or donor agencies.
Subsidised drilling by public/state drilling enterprises and
NGOs should be avoided. If considerable drilling is undertaken
directly by the public sector or private sector drilling capacity
is weak, stakeholders should develop a strategy for achieving
local private sector involvement in a time-bound manner.
Drilling enterprises and consultants should be registered and
issued with a licence or permit. This should be renewed on an
annual basis provided that permit conditions are met, includ-
ing the submission of drilling completion reports as specified.
A national drillers association should exist and be active in
discussing and expressing drillers concerns.
The public sector has tended to undertake the construction of
boreholes in many countries. However, the preferred option is
for construction to be undertaken by the local private sector
so as to improve efficiency and foster competition. Govern-
ment and donor support agencies as well as NGOs are thus
encourage to provide support which builds up the private sec-
tor, rather than to purchase state-owned drilling equipment.
If the local private sector is particularly weak, the asset base
and capacity can be built by the use of lease to purchase
mechanisms over a period of one to three years. Such mech-
nisms should be considered as they enable the capital cost of
drilling equipment to be progressively recovered over time
from contract payments.
In cases where support agencies have already supplied drilling
equipment there is need to ensure that there is support in the
form of spare parts, tools, management support and training,
for a ten-year period, following the rig commissioning.
If support agencies provided drilling rigs to Government
within the last seven years, a rig information management
system (Box 1) should be established, utilised and reported on.
Box 1. Outline for Rig Information Management System
A rig information management system (RIMS) is a simple da-
tabase which enables information regarding the utilisation,
maintenance and repair of drilling equipment to be recorded,
stored and analysed. It enables drilling programme managers
to monitor equipment productivity, track equipment use and
reduce misuse or abuse. A RIMS does not replace a national
borehole database, as it does not include all the necessary
information. Tt records the following:
Details of drilling rigs, compressors and support vehicles.
All equipment has a unique identification number and de-
scription.
List of the Region/State, Local Government and Village/
Community of operation. Each State and Local Govern-
ment has a unique identification code.
Details of each borehole drilled (i.e. location with GPS ref-
erence, borehole identification number, start date, com-
pletion date depth drilled, drilling time and idle time on
site).
Distance travelled (initial mobilisation as well as between
each individual site).
Down time (due to idleness, maintenance and repair).
The software needs to enable the following queries to be run:
Information on drilling activities for particular equipment,
state, district, community or period of time.
Information on maintenance and repair activities for par-
ticular equipment.
The RIMS software must be able to generate standard reports
and allow for the backup and restoration of data.
1. Professional Drilling
Enterprises and
Consultants
Competent Local Private Sector
Avoid Subsidised NGO or State Drilling Enterprises
Registration and Licencing of Drilling Enterprises
and Consultants
Drillers Association
5
Code of Practice for
Cost-Effective Boreholes
Principle 2 Procurement
Procurement procedures ensure that contracts are
awarded to experienced and qualified consultants and
drilling contractors.
Procurement should be through national government systems
rather than under direct contract to the donor or support or-
ganisation. If these systems are particularly slow or weak, a mix
of approaches should be used in order to improve the national
systems and at the same time receiving results in the field.
The engagement of construction companies for water well
provision should be through a national (or local) competitive
bidding process, involving pre-qualification. Engineers‟ est-
mates should be used to avoid contracts being awarded to
tenders below the cost price.
Procurement should be for a multi-borehole package, in a
sensibly defined geographic area, preferably with similar
hydrogeology. In countries where there are already a good
number of drilling companies, lots could be for a high number
of boreholes (e.g. 50). However, in countries where there is
need to promote new drilling companies, smaller lots should
be considered.
In order to draw upon and build in-country capacity, and en-
able smaller enterprises to compete with larger companies,
mechanisms of awarding role-over packages to a “driller‟s
pool” should be considered.
Procurement should not necessarily be limited to one year
contracts.
In-country tender and contract award procedures, i.e. the con-
stituted public procurement system, should be utilised and
strengthened where weak. In order to ensure that contracts
are awarded to experienced and qualified consultants and
drilling contractors a process of pre-qualification, tender and
contract award is recommended:
Human resource needs and equipment capability re-
quirements should be clearly defined. These should be in
line with well design and contract size.
A transparent and thorough pre-qualification process
based on the company profile, equipment and staff skills,
turnover, experience and past performance as well as ad-
herence to national regulations with respect to drilling
permits, licensing as well as membership of national pro-
fessional associations. Pre-qualification, which can be un-
dertaken every one to three years, should include visits to
the drilling company premises and, if possible, their on-
site operations during and after completion. The list of
pre-qualified contractors should be published.
Tender documents, drawings and specifications should be
based on the findings of the siting and endorsed by Local
Government and other key stakeholders prior to tender-
ing.
Definition of required outputs (locations, depths, drilling
conditions) at the tender stage. If this is not possible then
an open negotiated agreement on costs as set out in the
bill of quantities (Annex A1.1) should be undertaken.
In the absence of reliable information on drilling condi-
tions in a particular area, a tender meeting should be held
whereby a hydrogeologist who is intimate with drilling
conditions in the area describes the “categories of risk”.
This is discussed further under Principle 4 on Siting.
The tender or award process involving the submission of a
method statement should only be open to pre-qualified
contractors.
A clear and transparent contract award process.
Contracts packaging in terms of boreholes within close prox-
imity is intended to reduce mobilisation costs and to facilitate
contract supervision. It is advisable to package ten or more
wells together, bearing in mind that when too many wells are
in a package (e.g. hundreds) this can exclude small local con-
tractors.
Packaging can be a particular challenge in countries operating
in a highly decentralised manner. However, innovative solu-
tions such as rolling budget allocations from one year to the
next or drilling every 2 to 4 years in order to bulk up the num-
ber should be considered. Contracting out wells of similar
depth and hydrogeology in one lot facilitates the use of
smaller, less costly rigs where appropriate.
A mechanism to enable small companies to participate is to
award role-over packages to a driller‟s pool, i.e.:
Pre-quality a number of contractors.
Following the bidding process, identify contractors to be
part of the drillers pool for a specified term.
Negotiate and set drilling prices for an agreed area.
Award small roll-over packages of say 20 to 30 boreholes
to several contractors in the driller‟s pool. The drillers can
undertake the work consecutively.
As roll-over packages are completed, subsequent pack-
ages can be awarded depending on performance.
Such a mechanism enables contractors to work for more con-
tracts as high quality and timely construction wins new work.
Contractors with multiple rigs can take on several packages;
those with one rig can work according to their capacity. The
client has control over works being implemented.
Multi-borehole package in one geographic area with
similar hydrogeology and risk of dry borheoles stated.
Try to include works for water, health and education
departments.
Roll-over package for more than one year
2. Procurement National Partner Systems
Local Competitive Bidding Process
Pre-qualification
6
Code of Practice for Cost-Effective Boreholes
Principle 3 Contract Management, Supervision and
Payment
Adequate arrangements are in place to ensure proper con-
tract management, supervision and timely payment of the
drilling contractor.
Normally contract management and supervision should be
based on systems and personnel of Government although
additional expertise can be brought in to cover capacity gaps
with a view to building expertise over the long term.
Contract documents need to be straightforward and readily
understandable by drillers.
Payment for construction works should be timely.
A defects liability period should be upheld whereby a financial
retention (of the order of 10%) is held in an insurance bond,
bank guarantee or cash.
Ideally a robust legal framework that supports compensation,
financial retention mechanisms, and audit and compliance
procedures is required.
Expertise and personnel for the design, management, supervi-
sion and scheduling of drilling programmes is essential to en-
sure that wells drilled are of high quality and that drilling costs
are reasonable. Waiting time at the drill site while decisions
are taken can raise the overall drilling costs considerably. Pro-
ject planning should ensure that drilling in the rainy season is
avoided.
Contracts for water well drilling can be paid according to bills
of quantities (Annex 1) or as a lump sum. Although lump sum
contracts are simpler to manage, with less scope for manipula-
tion, it is still essential that supervision is competent. Overall,
the contract must ensure that it is in the driller‟s interest to
construct a high-quality borehole. Lump sum contracts are
more appropriate under conditions where there is no payment
for dry wells. However this requires a categorisation of the
risks of drilling a dry borehole and appropriate payment
mechanisms, such as set out in Annex 2. Contracts may either
bundle the pump installation with the borehole construction
or handle this separately, e.g. more localised procurement and
installation by local mechanics.
In cases where performance bonds from a bank can only be
secured through cash, it is preferable that Contracts insist on
insurance bonds from a reputable company.
Proper supervision is a good investment which provides high
quality construction, ensures wells are not drilled deeper than
necessary and prevents holes from being abandoned prema-
turely. There is need for regulation of drilling supervision. Wa-
ter well drilling works should preferably be supervised full time
by skilled and qualified personnel in order to ensure high
quality construction. Part time supervision should only be un-
dertaken for lump sum contracts, for which it is essential that
supervision of the pumping test is undertaken and the yield as
well as borehole depth measured.
Staff of partner organisations (with adequate financial and
human resources), or private sector consultants should under-
take drilling supervision. Supervisors need to be well-trained
and operate independently from the driller in terms of finance
and logistics. Remoteness should not be an excuse for not
undertaking supervision. Typical problems of poor drilling su-
pervision are:
Driller claims bore is deeper than reality
Borehole of smaller diameter than specified is drilled
Borehole drilled deeper than necessary as driller is paid
against a bill of quantities and tries to maximise revenue.
Incorrect screen placement
Insufficient /poor specification gravel
Lack of grout
Not enough development
Driller claims well successful, but in reality it is dry.
Community monitoring of the construction and supervision
should also be considered. If properly trained, communities
can, for example monitor the number of casing pipes installed,
number of bags of cement used by the contractor and pres-
ence of the supervisor.
It is not uncommon for boreholes which are signed off as suc-
cessful go dry within a short time due to poor construction.
Thus a defects and liability clause, with about 10% retention of
contract value, needs to be included in the Contract and en-
forced. Toward the end of the 12-month period, under the
terms of the Contract, supervisors are obliged to visit each
completed site for the final sign off, which includes confirma-
tion of viability with the water users. It is essential that the
Contract clearly stipulates who is responsibility for pump qual-
ity within the warranty period.
Payment for works should be made within one month of com-
pletion and should not extend to more than three months.
Delays for longer than this are not acceptable for drillers to
maintain their liquidity (cash flow) and should incur pen-
alty/interest payments.
Third party monitoring, paid for by the client but undertaken
by an independent trained professional following construction
can also be undertaken as a control mechanism. This requires
a well-defined and consistent checklist for every water-well
drilled, with the results published.
In cases where the required legal framework and public insti-
tutions to underpin contract management procedures are
weak, there is need for considerable emphasis on building the
required systems through legislation and improving capacity.
3. Contract Management,
Supervision and Payment
Proper Contract Management
Proper Supervision by Pofessionals & use National Systems
Straightforward and Understandable Contract Documents
Timely Payment
Defects Liability Period
Robust Legal Framework
7
Code of Practice for
Cost-Effective Boreholes
Principle 4 Borehole Siting
Appropriate siting practices are utilised.
Prior to preparing any well construction contract, a hydro-
geological desk study and field reconnaissance need to be be
carried out and the method of siting boreholes agreed upon,
based on expert opinion.
The risk of drilling an unsuccessful borehole should be catego-
rised. In proven areas where the geology is well understood
and borehole success is high (say over 70%), it may not be
necessary to site wells using geophysical survey techniques.
The final site selection needs to take community preferences
with respect to convenience into account.
Determining the best site for a borehole requires considera-
tion of technical, social and institutional issues. The siting
process should show which groundwater conditions dominate
the project area and enable the borehole(s) design to be
specified. Professional siting involves desk and field reconnais-
sance, and makes full use of existing data. In order to deter-
mine the best place for a borehole seven factors are of par-
ticular importance:
Sufficient yield for the intended purpose: The ground-
water aquifer should have a sufficient yield for a rural wa-
ter supply handpump (around 0.3-0.5 l/sec), for a small
town water supply (1-10 l/sec), or for a larger scale need
such as a significant irrigated area. This information is
sometimes available from documents or can be derived
performing a pump test.
Sufficient renewable water resources for the intended
purpose. Although a well may be capable of delivering a
certain yield in the short to medium term, if the ground-
water is not regularly replenished by infiltration from rain-
fall or river flow, then that yield will not be sustained over
the long term. It is important therefore to evaluate the
likely recharge to the aquifer, and how this might vary
with time. This judgement can be based on a water bal-
ance of an area calculated in a conceptual water model.
Appropriate water quality for the intended purpose.
Different water uses impose different water quality re-
quirements. Domestic water must be free of disease
pathogens (which are carried in human excreta) and low
in toxic chemical species such as arsenic or fluoride. When
using groundwater for irrigation the level of salinity has to
be checked. Well siting must therefore take account of
know-ledge of the occurrence of such undesirable sub-
stances.
Proximity to the point of use. Within the constraints of
geology, groundwater resources and groundwater quality,
wells should ideally be sited as close as possible to the
point of use. This means that walking distances to collect
water from rural point sources (eg handpump wells) and
energy costs for piped supplies should be minimised. If
not known, detailed interviews within the community
should be undertaken to get this information before per-
forming the siting.
Access by construction and maintenance teams. In the
case of wells constructed by heavy machinery, access by
drilling rigs, compressors and support vehicles is crucial.
Even when lighter equipment is used, vehicle access for
construction and for maintenance is important. Site se-
lection must therefore take account of these needs.
Avoidance of interference with other groundwater
sources and uses. In areas where some groundwater de-
velopment has already taken place, the construction of a
new well can lead to increased drawdown1 in existing
sources. This in turn can lead to greater pumping (en-
ergy) costs in both the existing well and the new well, re-
duced yields, changes in groundwater quality and poten-
tial conflict. In an early phase of the siting process possi-
ble interferences and risks for derogation have to be de-
scribed and discussed. In high risk situations possible al-
ternative siting areas should be evaluated.
Avoidance of interference with natural groundwater
discharges. In a similar way, the construction of a well
too near to natural springs, watercourses or wetlands can
lead to a reduction of water levels, potentially drying up
these important water sources and ecosystems and affect-
ing uses and users dependent upon them. The intrusion
of salt water due to too high abstraction of groundwater
near the coast could lead to irreversible decline of water
quality.
If skills for borehole siting are lacking in the country, efforts
should be made to build long-term capacity in this regard.
As part of borehole siting, the risk of drilling a dry borehole
should be categorised, e.g. high, medium and low risk as set
out in Annex 2.
In the case of boreholes which are to be fitted with hand-
pumps, geophysical techniques (e.g. resistivity, conductivity)
are rarely required once the general hydrogeology of a given
area is known. Drilling small exploratory boreholes (e.g. with a
small hand auger) can also be a suitable siting method for
shallow wells in certain conditions.
Engagement with the community to agree on the well location
is essential and requires some negotiation to explain technical
constraints while taking community preferences into consid-
eration. In general the community would be expected to indi-
cate three preferred boreholes sites in their locality, in order of
priority.
4. Borehole siting Hydrogeological Desk Study and Field Reconnaissance
Categorisation of risk and use of geophysical survey
technique only where appropriate.
Community Preference Considered for Site Selection
8
Code of Practice for Cost-Effective Boreholes
Principle 5 Construction Method
The construction method chosen for the borehole is the
most economical, considering the design and available
techniques in-country. Drilling technology needs to match
borehole design.
Well depths should not be unnecessarily over-specified or un-
der-specified.
A stepped approach to technology selection should be fol-
lowed. Firstly very low cost methods, including hand dug wells
and manual drilling, are considered before mechanised drilling
if they are feasible.
Subsequently, the use of small rigs which provide specified
diameter and well depth and can reach remote locations should
be considered.
It is important that well depths are not properly specified.
Stakeholders should avoid over-specifying depths and diame-
ters on a „just in case‟ basis, in order to then over-specify the
drilling rig required. This results in the mobilisation of excess
equipment and raises costs. However, excessive under-
specification is also a problem. Tendencies can be analysed by
comparing specifications with actual drilled depths.
Tender and contract documents should enable the least expen-
sive, but suitable drilling equipment to compete against larger,
more expensive rigs. Tenders should specify the final product
(i.e. the drilled water well) and thus avoid over-specifying the
drilling equipment. Small, low cost mechanised rigs drill at lower
cost than large rigs, can often be transported on the back of a
four-wheel drive pickup or single axle trailer and can reach
more locations, particularly where road networks are poor. If
stakeholders do not know about small mechanised drilling
technologies, explicit efforts should be made to raise awareness.
It should however be noted that drilling with a smaller rig may
be slower, and will thus require longer supervision. This needs
to be fully considered when considering contract management
and supervision requirements.
Hand dug and manually drilled wells are an option in specific
environments (soft formation and shallow groundwater). In ar-
eas where such techniques can provide water wells in significant
numbers, they should be fully considered. However, borehole
verticality needs to be good enough to enable the installation
and operation of the specified handpump, and wells need to be
deep enough to sustain supplies in prolonged dry periods and
successive dry years. There is need for the use of appropriate
quality control.
Dissemination of information, exchange visits, pilot projects,
support to the local private sector, and in-country studies may
be necessary in areas where hand dug wells or manual drilling
techniques are not well known about or not common.
The three conventional mechanised drilling techniques to
achieve boreholes suitable for hand-pumps are mud-circulation
boring, air-percussion boring or combination boring (mud-
circulation drilling through collapsible over-burden to rock, then
air percussion drilling).
In order to improve the availability of spare parts for drilling
equipment in countries with low levels of industrialisation the
private sector should be encouraged to partly standardise on
their drilling equipment. However, final decisions lie within the
hands of the private contractors, and the danger of creating a
monopoly for suppliers needs to be considered. It may be eas-
ier to discuss such practices with a drillers association (if it ex-
ists).
Proper specification of well depths.
5. Construction Method
Stepped approach to technology selection with very low
cost methods (hand dug wells and manual drilled wells)
considered first.
Appropriate drilling rig selection.
9
Code of Practice for
Cost-Effective Boreholes
Principle 6 Borehole Design and Construction
The borehole design is cost-effective, designed to last for a
lifespan of 10 to 30 years, and based on the minimum speci-
fication to provide a borehole which is fit for its intended
purpose.
Minimum specification for „fit for purpose“ well in terms of yield,
diameter, depth, casing and screen, gravel pack/formation
stabiliser, verticality, drilling additive and sanitary seal. Over-
design of boreholes, especially excessive depth or diameter, is
wasteful and should be avoided.
The sustainability of the groundwater resource is fully
considered. The procedures for well development and for
pumping test are agreed upon and clearly specified in the
drilling contract.
The drilled well must be developed until the water is free of
solids and fine materials (fines) and any turbidity for a
continuous period of 30 minutes.
Pumping test requirements for a handpump should be realistic
and not over-specified.
Water quality testing for specified chemicals is undertaken,
particularly for areas at risk and boreholes serving institutions.
A fit for intended purpose design is summarised below. In the
case of motorised systems (if deemed cost-effective), design
must account for the precise requirements of the system.
In terms of yield for a handpump, 1m3/hour is sufficient
although this may be dropped to 400 litres/hour in areas
where groundwater is difficult to find. Wells should only be
drilled to the required depth for this yield. However, ex-
pected variations in the level of the water table should also
be considered. It should allow for expected drawdown, sea-
sonal fluctuations, multi-year trends and deterioration in
well efficiency. Yield requirements for motor pumps depend
on the system design, which is based on user requirements
and can be significantly higher than that of a hand pump.
Handpump borehole diameter requirements and the small
diameter pumps now on the market mean that 4”
(~100mm) internal diameter cased boreholes are usually
sufficient for the handpump cylinder and rising main. Nor-
mally uPVC casing/screen is stipulated which has a mini-
mum internal diameter of 103mm and an outside diameter
of 113mm. Motor-pumped boreholes can completed with a
cased pump housing of 5” nominal diameter to permit
space for an electro-submersible pump.
Depth: In locations where superficial weathered formations
are likely to be of a sufficient thickness, permeability and
storage to support the required yield, and deal with fluctua-
tions in the water level, the use of a relatively shallow well
(screened and gravel packed), constructed by a small drill-
ing rig may be cost effective.
Plain casing and screen: In locations where boreholes are
drilled into stable basement formation, it is possible to
make savings by casing the collapsing formation only.
However, the interface between the collapsing formation
and hard formation must be sealed (e.g. with grout). Plastic
(pVC) casing and screen should be used in preference to
steel where wells are less than 100-120m in depth. In fine
sands it may be necessary to use geo-textile materials (filter
socks) for the screen.
Gravel pack/formation stabiliser should have a proper
grading with a quality of >95% silica. It needs to be in-
stalled slowly and carefully, preferably with a “tremmie
pipe” and funnel.
Verticality needs to be specified (<100mm for every 30m),
as a condition of the borehole being denoted as successful.
Verticality should be such that a standard hand-pump cyl-
inder can be lowered into the borehole without meeting
any resistance).
Chemical foam and biodegradable mud should be utilised
as drilling additives in preference to bentonite and other
non-degradable mud. Bentonite should not be used as a
drilling mud once the drilling progresses below the water
table.
A sanitary seal is essential. It requires that the annulus is
backfilled (with drilling spoil) and then sealed with grout to
a depth of at least 4m. It is essential that no contaminated
water (e.g. from the surface or from pit latrines) can leak
into the borehole or the aquifer. A cement platform which
drains pumped water away from the borehole is required.
Annex 3 sets out sample borehole designs for the major hydro-
geological formations.
Well development must be undertaken before the driller
moves to the next site. If the screen and gravel pack area is not
properly flushed well efficiency can drop and the screen can
block over time. Well development is best undertaken with
compressed air thoroughly applied to all of the screened areas.
The borehole should be flushed until it is free of fines and tur-
bidity for a continuous period of 30 minutes. Chlorine can be
introduced before well development to help break down the
drilling polymer. Once the lifted water is clear, then the amount
of water being voided from the well by the air-lift should be
quantified and the measured “airlifted yield” recorded.
Pumping test is undertaken to establish well efficiency and
assess well yield. Requirements appropriate for a hand pump
are continuous pumping for 3 to 6 hours. It can be done only
until stable pumping water level is achieved for a constant rate
of discharge. Normally, the discharge rate should be at least
double the specified national minimum discharge for a success-
ful borehole. Recovery should be measured for half the pump-
ing time. In the case of motorised wells, more comprehensive
drawdown and recovery tests should be undertaken (e.g 24-
hour pumping tests).
Water quality analysis in line with national guidelines should
be undertaken and results submitted to the appropriate author-
ity. On site testing should be used when possible.
6. Borehole Design and
Construction Appropriate well development
Minimum specification for „fit for purpose“ well in terms of yield,
diameter, depth, casing and screen, gravel pack/formation
stabiliser, verticality, drilling additive and sanitary seal
Suitable pumping test requirements
Water Quality Analysis
10
Code of Practice for Cost-Effective Boreholes
Principle 7 Data and Information
High quality hydrogeological and borehole construction
data for each well is collected in a standard format and
submitted to the relevant Government authority.
The data to be gathered during borehole drilling is specified in
the drilling contract and responsibilities for data collection be-
tween the contractor and the supervisor are clear.
Information, in the form of a national borehole completion re-
port should be submitted to the appropriate government au-
thority after drilling (even in the case of dry boreholes).
Renewal of drilling licences should be linked to the submission
of borehole completion reports.
Each borehole drilled in the country should have its own dedi-
cated identification number.
Government, and other water sector stakeholders should collate
data on borehole drilling programmes annually, and make the
reports available to the public.
Formats for borehole completion records need to include in-
formation on the location, drilling operation, casing and well
completion, lithology, well development and pumping test and
water quality. Annex 4 provides a recommended format for
borehole completion records. It is essential that this information
is submitted to the appropriate centralised Government author-
ity and that each project does not merely hold on to its own
data.
The importance of regulation and licensing of drilling contrac-
tors is noted under principle 1. As a condition of annual drillers
licence renewal, it is recommended that it is made obligatory for
drillers to submit a bound compilation of their Completion Re-
ports of annual output for the preceding year to the appropriate
authority.
Each borehole dedicated identification number should be
stamped onto a metal plate on the hand-pump base and also
engraved into the pump platform. In order to avoid the un-
planned and unmonitored drilling of boreholes, permits should
be issued by the appropriate authority.
In terms of information on drilling programmes by Government
and other stakeholders, the key areas to be reported include:
Programme outputs (with associated costs) in terms of
skills, knowledge and organiational capacity raised as well
as numbers of people trained.
Boreholes drilled, i.e. numbers, well depths, and locations
(with borehole numbers and GPS references annexed).
Supervision summary.
Price of each well, with details on what is included and ex-
cluded, (e.g. profit and overheads, siting, mobilisation, drill-
ing, supervision, handpump, training of the community). In-
clude an explanation of how costs are derived (e.g. cost of
package of 10 wells in a particular contract package divided
by 10). Information needs to be structured in a way that en-
ables comparisons between regions and /or districts to be
carried out.
Details of private sector involvement including names of
companies, contract summary and amount, date paid for
construction and defects liability payment.
Findings of monitoring and evaluation missions.
Specify data requirements and responsibilities
Submit borehole completion log to authority
Unique borehole identification number
Annual reports on drilling programmes
available to the public
7. Data and Information
Drilling licence renewal linked to submission
of completion reports
11
Code of Practice for
Cost-Effective Boreholes
Principle 8 Database and Record Keeping
Storage of hydrogeological data is undertaken by a central
Government institution with records updated, information
made freely available and used in preparing subsequent
drilling specifications.
A national (or state level) database of all borehole drilling re-
cords should be established and kept up-to-date. If no such
national database exists, sector stakeholders should keep and
archive records of all borehole drilling work undertaken until it
is established.
The data from all drilling programmes and projects in the coun-
try should feed into this database.
Data from the database should be made freely available.
The cumulative knowledge of groundwater resources provided
by adequate and accessible data archives greatly enhances the
chances of successful drilling and borehole construction. Bore-
hole logs, completion reports and pumping test data (as speci-
fied in the drilling contract) must always be submitted to the
relevant national (and/or) local authority. Information from “dry”
or unsuccessful boreholes is just as important as that from the
unsuccessful ones.
There is need for specific key data to be abstracted from the
drilling completion reports and entered onto a national data-
base for borehole drilling. Such a database needs to be properly
established, kept up to data, be readily accessible to all, and
ensure that there is no duplication of data entry (i.e. by using an
individual borehole identification number and GPS information).
If there is no national database, drilling data should be archived
by sector stakeholders until such a mechanism, with responsible
agent, is established. Government and external support organi-
sations should be encouraged to enforce data gathering, estab-
lish groundwater databases and build the national capacity in
this regard.
It is internationally accepted that to assess progress and status
of national groundwater development and guide future plan-
ning, it is necessary to maintain good records of borehole drill-
ing, and index and archive original documents so that they can
be readily accessed. Records should include:
Pre-qualification and tender evaluation reports.
Reports of community mobilisation and training.
Schedules of construction supervision.
Monitoring reports.
Principle 9 Monitoring and Evaluation
Regular visits to completed boreholes are made to monitor
their functionality in the medium as well as long term with
the findings published.
The monitoring and evaluation systems of Government should
be utilised (and strengthen if necessary) rather than the devel-
opment of parallel systems.
Monitoring of the use of the borehole and pump functionality,
including analysis and action-taking should be undertaken at: 6
months, one year, five years and ten years after construction at
a miminum.
The findings of the monitoring work should be made public.
It is essential that the procedures for monitoring and evaluation
as set out by Government are respected, and/or improved, with
all information collected communicated to the relevant authori-
ties.
Monitoring of water source functionality should include the
collection of information on revenue collection, management,
reasons for breakdown and user response. Findings should in-
form national policies with respect to infrastructure develop-
ment as well as operation and maintenance. Actions taken
should be in line with national policies.
Use national monitoring and
evaluation systems 9. Monitoring
and Evaluation
Monitor use and functionality
at least: 6 months, 1 year, 2
years, 5 years and 10 years
after installation
Publish monitoring reports.
8. Database and
Record Keeping National database of all drilling
records (or archive all records)
All drilling programmes, projects
and works feed into the database
Information from database is
freely available and used
12
Code of Practice for Cost-Effective Boreholes
Annex 1 Bills of Quantities
Tables A1.1 and A1.2 provide two sample BoQs.
Table A1 Sample of Bill of Quantities for 10 wells - Long Version
Description Qty Unit Unit Price
Total Price
1 Borehole Siting 1 Each
2 Establishment of Base Camp
3 Mobilisation and demobili-sation of equipment and personnel
500 km
4 Set up of rig and move be-tween sites
400 km
5 Drilling borehole of 5” di-ameter in soft overburden
200 m
6 Drilling borehole of 5” di-ameter in basement rock
300 m
7 Supply, install and withdraw temporary casing
10 each
8 Sampling and Borehole Log-ging
10 Each
9 Supply and installation of 110mm (4 inches) diameter, uPVC casings of 10 bar pres-sure rating.
400 m
10 Supply and installation of 110mm (4 inches) diameter, uPVC screens of 10 bar pres-sure rating. (Slot size 0.5)
100 m
11 Supply and place approved filter pack around casings and screens
90 m
12 Borehole cleaning & devel-opment till water is silt free
20 hour
13 Test Pumping 5 each
14 Provide and place cement grout
5 each
15 Water Quality Analysis and borehole disinfection
5 each
16 Installation of handpump and accessories.
5 each
17 Completion Reports – Spiral bound copies
15 Each
18 Waiting (or standing) Time hour
Sub-total
18 Overheads and profit -15%
Value Added Tax (VAT)- 20%
Total
In Table A1.2, items have been streamlined and the margin
(profit plus overheads) is incorporated into the rates for the
various items. Note that BoQs are not problem-free. We have
found examples where there is no item included for moving
between the drill sites, or where the specified drilling depths,
casing and screen do not make any sense!
Table A1.2 Sample of Bill of Quantities (BoQ) (Streamlined Version)
Description Qty Unit Unit Price
Total Price
1 Mobilisation 1 LS
2 Moving between sites 5 LS
3 Drilling 200 m
4 Casing and Completion 400 m
5 Gravel Pack and Development 100 m
6 Test Pumping 5 LS
7 Backfill and well completion (including water quality analy-sis)
5 LS
8 Installation of handpump and accessories.
5 each
9 Completion Reports – Spiral bound copies
15 each
Sub-total
Value Added Tax (VAT)- 20%
Total
13
Code of Practice for
Cost-Effective Boreholes
Annex 2 Categorisation of Risk and Payment Structures
It may be possible to classify the drilling potential for different parts of the country, or within a particular location into the follow-
ing categories:
Category Success
Rate* Assumptions Proposed Payment Arrangements
A
High
Success
> 90%
Geophysical survey not
necessary. Drilling at any
site has a high chance of
success. First preference of
community is likely to be
successful.
The risk of dry drilling is denoted as small and dry bores are not paid to
the contractor, under any circumstance. Driller is to survey select site
within the areas nominated by the community and his unit rates is to in-
clude the risk of dry bores.
B
Moderate
Success
70 - 90%
The drillers themselves may
elect to survey (either
themselves or by their ap-
pointed hydro-geologist)
and select the actual dill
sites within the given pre-
ferred areas of community.
Government guidelines for
siting should be followed.
In some cases it is advis-
able to specify a minimum
drilling depth in the Con-
tract.
Limited payment is made to the Contractor for dry bores to a certain
depth, according to formula set out below:
1st bore success: 100% paid; move to new location.
If 1st bore dry: No payment
2nd bore success: 100% paid, move to new location.
If 2nd bore dry: 50% (of a productive borehole) paid
3rd bore success: 100% paid, move to new location
If 3rd bore dry: 50% (of a productive borehole) is paid move to next
community
In the exceptional event of three dry bores, then no further drilling is un-
dertaken in this community at this juncture. In effect this community lo-
cale will now become a Category C risk and requires expert hydro-
geological survey to be commissioned by the Employer in order to ascer-
tain define site(s) for any further drilling.
C
Low
Success
< 70%
Client to commission inde-
pendent siting including
use of geophysics (Resistiv-
ity profiling and Electro-
magnetic (EM) assessment.
Sites selected and contrac-
tor drills to minimum depth
indicated
The employer has determined the actual site and depth; payment is made
for both wet and dry bores.
*The suggested percentages applied above can be varied to suit, for example 85%, 55-85% and 55% respectively.
A maximum of three dry boreholes may be made in any one community under the above arrangement, in accordance with their
preferred sites. Subsequently it is time to cease “random” drilling and undertake geophysical investigations.
14
Code of Practice for Cost-Effective Boreholes
Annex 3: Sample borehole designs
15
Code of Practice for
Cost-Effective Boreholes
16
Code of Practice for Cost-Effective Boreholes
17
Code of Practice for
Cost-Effective Boreholes
18
Code of Practice for Cost-Effective Boreholes
Annex 4. Suggested Format for Borehole Completion Record
Contents
1. General
2. Drilling Operation
3. Casing and Well Completion
4. Well Development and Pumping Test Summary
5. Water Quality
6. Lithology
6a. Lithological Logging
6b. Abbreviations for Lithological Logging
6c. Photograph of Generalised Lithology
7. Pumping Test Details
7a. Step Drawdown Test
7b. Constant Rate Test
7c. Recovery Test
8. Water Quality Analysis Parameters (full list)
19
Code of Practice for
Cost-Effective Boreholes
1. General
Water Well Reference No: Use: Community Household/Private Compound Health Facility Education Facility Company Premises Test Well Other
Location: Owner Name:
Owner Address: Coordinates/GPS Refer-ence:
Long. E Lat. N
Financing Programme/Project/Private:
Well Permit No. Date Issued: Issuing Authority
Name of Driller: Driller’s License No:
Address of Driller:
Sketch Map Approximate Scale:
2. Drilling Operation
Start Date: Total Depth: m Drilling method(s):
Percussion Mud Rotary Air Rotary DTH
Equipment make: __________________
Hand Drilled (specify type) __________________
Main Water Strike: m
Completion Date: Static Water Level: m
Dynamic Water Level: m
Drilling Diameter: inch mm Average Penetration Rate: m/h
From To Diameter (inch/mm) Method Penetration Rate (m/h)
m m
m m
m m
m m
m m
m m
m m
m m
m m
20
Code of Practice for Cost-Effective Boreholes
3. Casing and Well Completion
Casing Material: _____________________
Casing Joints: Threaded Glue and Socket
Bottom Plug: Yes No
Height above ground level: ______________m
Plain casing and Screen installation: inch mm
Screen Open Area (%) ______
Casing
From To Diameter (inch/mm) Type
m m
m m
m m
m m
m m
m m
Screen
From To Diameter (inch/mm) Type Slot Size
m m
m m
m m
m m
m m
m m
Gravel
From To Size Volume used
m m
m m
Backfill and Grout
From To Diameter (inch/mm) Type
Alignment/Verticality Test Remark
Well head and Platform
Well Cap: Yes No
Apron:
Concrete slab
Drainage
Soak-away Pit
Fence
Pump:
Stand
Fitted around casing
Welded on Casing
Pump Type:____________________________________
Comments: _______________________________________________________________________________________
21
Code of Practice for
Cost-Effective Boreholes
4. Well Development and Pumping Test Summary
Development:
Air-lift
Over-pumping
Surging
Backwashing
Jetting
Duration _____________hr
Comments: ___________________________________
______________________________________________
Pumping Test:
Air-lift capacity evaluation
Constant Rate Test (CRT)
Step Drawdown Test
Duration _________hr
Discharge ________l/s
Dynamic water level: _________m
Comments: ___________________________________
______________________________________________
5. Water Quality Summary
Sample taken: Yes No
Date____________
Chemical Quality:
pH:_______________
Laboratory: __________
(for more parameters see separate sheet) Physical Quality:
Clear
Turbid
Other (please specify) __________________
Colour_______ Taste_______ Turbidity______NTU
Temp. ______˚C TDS______mg/l EC_______µS-cm
Bacteriological Quality:
Faecal coliform: ____________cfu per 100ml
Laboratory: __________
Comments: _________________________________________________________________________________
22
Code of Practice for Cost-Effective Boreholes
6a. Lithological Logging
Water Well Reference No:
Location: Owner Name:
Owner Address: Coordinates/GPS Reference: Long. E Lat. N
Financing Programme/Project/Private:
Well Permit No. Date Issued: Issuing Authority
Name of Driller: Driller’s License No:
Well Logged by:
Depth (m)
Description Colour* Grain size* Texture* Degree of weathering*
Stratigraphic unit (if
known)*
Remarks (e.g. mineralogy,
drilling, water)
Penetration rate
(min/m)
Discharge EC TDS
Data to be recorded at a minimum of 1 meter intervals- add more sheets if required
* See below for codes
23
Code of Practice for
Cost-Effective Boreholes
6b. Abbreviations for Lithological Logging
Colour (use combinations if needed)
Gr - grey Gn - green Br-brown Or – orange
Bg-beige Rd-red Pk- pink Wt – white
Shade
L-light M-medium D-dark
Grainsize
VF - very fine F - fine M - medium C – coarse VC - very coarse
Texture (use more than one as applicable)
D - Dense, hard F - fractured U- unconsolidated PC- partly consolidated
L - laminated H- homogeneous C - clast supported M- matrix supported
Degree of weathering
F-fresh L-light M-moderate D-deeply
Formation / Stratigraphic unit (if known - add codes based on the local stratigraphic nomenclature)
6c Photograph of Generalised Lithology
(Sample photograph from Zambia)
24
Code of Practice for Cost-Effective Boreholes
7. Pumping Test Details
7a. Constant Rate Test (note that 3 to 6 hours is sufficient of a handpump supply)
Water Well Reference No: Water Well Name:
Start Test Date: Time of Day
Static Water Level before the Test m
Data in this table is for: Pumping Well/ Observation Well (Tick Appropriate)
Reference Point
Average Discharge ( l/sec) Obs Well No. Distance (m) Depth (m)
Time Water Level Discharge (Q) Remark
Real Time Hrs Min
Depth of Water Drawdown
Container Method Flow Meter TDS, Temperature, pH and
any other observation (m) (m) (l/s or m3/h) (l/s or m3/h)
0
0.5
1
2
3
4
5
6
7
8
9
10
12
14
16
18
20
25
0.5 30
35
40
45
50
1 60
70
80
1.5 90
100
110
2 120
135
150
165
25
Code of Practice for
Cost-Effective Boreholes
Time Water Level Discharge (Q) Remark
Real Time Hrs Min (t)
Depth of Water
Drawdown (S)
Container Method Flow Meter TDS, Temperature, pH and
any other observation (m) (m) (l/s or m3/h) (l/s or m3/h)
3 180
195
210
225
4 240
255
270
285
5 300
315
330
345
6 360
26
Code of Practice for Cost-Effective Boreholes
7b. Step Drawdown Test (for mechanized borehole supply)
Water Well Reference No: Water Well Name:
Start Test Date: Time of Day:
Static Water Level before Test: m
Pump Intake: m
Reference Point Pumping Well/ Observation Well (Tick Appropriate)
Average Discharge: l/sec Obs Well No. Distance m Depth m
Time Water Level Discharge (Q) Remark
Real Time Hrs Min
Depth of Water Drawdown
Container Method Flow Meter TDS, Temperature, pH and
any other observation (m) (m) (l/s or m3/h) (l/s or m3/h)
0
0.5
1
2
3
4
5
6
7
8
9
10
12
14
16
18
20
25
0.5 30
35
40
45
50
1 60
70
80
1.5 90
100
110
2 120
135
150
165
27
Code of Practice for
Cost-Effective Boreholes
Time Water Level Discharge (Q) Remark
Real Time Hrs Min (t)
Depth of Water
Drawdown (S)
Container Method Flow Meter TDS, Temperature, pH and
any other observation (m) (m) (l/s or m3/h) (l/s or m3/h)
3 180
195
210
225
4 240
255
270
285
5 300
315
330
345
6 360
375
390
405
7 420
435
450
465
8 480
495
510
525
9 540
555
570
585
10 600
615
630
645
11 660
675
690
705
12 720
735
750
765
13 780
795
810
28
Code of Practice for Cost-Effective Boreholes
Time Water Level Discharge (Q) Remark
Real Time Hrs Min (t)
Depth of Water
Drawdown (S)
Container Method Flow Meter
TDS, Temperature, pH and any other observation
(m) (m) (l/s or m3/h) (l/s or m3/h)
825
14 840
855
870
885
15 900
915
930
945
16 960
975
990
1005
17 1020
1035
1050
1065
18 1080
1095
1110
1125
19 1140
1155
1170
1185
20 1200
1215
1230
1245
21 1260
1275
1290
1305
22 1320
1335
1350
1365
23 1380
1395
1410
1425
24 1440
29
Code of Practice for
Cost-Effective Boreholes
7c Recovery Test
Water Well Reference No: Water Well Name:
Start Test Date: Time of Day:
Water Level Before the Test m Pumping Well/ Observation Well (Tick Appropriate)
Reference Point
Time Water Level Time Water Level
Real Time Hours Minutes
Depth of Water
Residual Drawdown
Real Time Hours Minutes
Depth of Water
Residual Drawdown
m m m m
0 8.5
0.5 9
1 9.5
2 10
3 10.5
4 11
5 11.5
6 12
7 13
8 14
9 15
10 16
12 17
14 18
16 19
18 20
20 21
25 22
0.5 30 23
35 24
40 26
45 28
50 30
1 60 32
70 34
80 36
1.5 38
100 40
110 42
2 44
2.25 46
2.5 48
2.75 50
3 52
3.5 54
4 56
4.5 58
5 60
5.5 62
6 64
6.5 66
7 68
7.5 70
8 72
9 74
30
Code of Practice for Cost-Effective Boreholes
8. Water Quality Analysis Parameters (full list)
Water Well Reference No:
Constituents Unit Concentration
Suspended solids mg/l
Colour TCU
Turbidity NTU
TDS mg/l
pH
Hardness (CaCO3) mg/l
Calcium (Ca) mg/l
Magnesium (Mg) mg/l
Sodium (Na) mg/l
Potassium (K) mg/l
Chloride (Cl) mg/l
Total Alkalinity mg/l
Bicarbonate mg/l
Carbonate mg/l
Sulphate mg/l
Nitrate mg/l
Flouride mg/l
Iron mg/l
Manganese mg/l
Zn mg/l
Copper mg/l l
Arsenic mg/l
Lead mg/l
Aluminium mg/l
Cadmium mg/l
Cyanide mg/l
Mercury mg/l
Ammonia mg/l
Hydrogen Sulphide mg/l
Faecal Coliform Count/100ml
Total Plate Count Count/100ml
Field Measurements
Temperature 0C
pH
Electrical Conductivity
References and Further Reading
Adekile, D and Kwei, C. 2009. The Code of Practice for Cost-Effective Boreholes in Ghana – Country Status Report, Consul-
tancy Report for RWSN/UNICEF
Adekile, D and Olabode O. 2008. Report on comparison of Cost-Effective borehole drilling in the Project Sates and other
Programmes. Consultancy Report for UNICEF Nigeria Wash Section.
Armstrong, T. 2009. The Code of Practice for Cost-Effective Boreholes in Zambia – Country Status Report, Consultancy Re-
port for RWSN/UNICEF
Ball, P. Solutions for Reducing Borehole Costs in Rural Africa. Field Note RWSN/WSP
Carter, RC. 2006. Ten-step Guide Towards Cost-effective Boreholes. Field Note RWSN/WSP
Danert, K. 2009. Learning from UNICEF’s Experiences of Water Well Drilling, UNICEF Internal Document
Duffau, B. and Ouedraogo, I. 2009. Optimisation du Cout des forages – Raport de Mission, Consultancy Report for
RWSN/UNICEF
MacDonald, A, Davies, J, Calow R and Chilton J. 2005. Developing Groundwater. A guide for Rural Water Supply, ITDG Pub-
lishing
Potential Forthcoming Documents (aid Memoire)
Water Well Drilling Short Contract
Field Note on Drilling Supervision
Overview of light and medium drilling rigs
Authors and Reviewers Contact
Kerstin Danert, Tom Armstrong, Dotun Adekile, Bruno Duf-
fau, Inoussa Ouedraogo and Clement Kwei are the authors
of the Generic Code of Practice for Cost-Effective Bore-
holes.
The report has been peer reviewed by Peter Harvey
(UNICEF), Ron Sloots (WE Consult), Richard Carter
(WaterAid), John Chilton (British Geological Survey) and
XXXXX (to be completed after the third review.
Note Dew Point input XXXXX.
The Rural Water supply Network (RWSN) is a global
knowledge network for promoting sound practices
in rural water supply.
RWSN Secretariat Phone: +41 71 228 54 54
SKAT Foundation Fax: +41 71 228 54 55
Vadianstrasse 42 Email: [email protected]
CH-9000 St.Gallen Web: www.rwsn.ch
Switzerland
Development of the Code of Practice
The preparation of this document was led by Dr Kerstin
Danert of Skat who managed a UNICEF/USAID funded pro-
ject to develop a Code of Practice for Cost-Effective Bore-
holes. The project included a review of the history of
UNICEF‟s involvement in borehole drilling, followed by
country studies in Burkina Faso, Ghana and Zambia. Ongo-
ing work to develop national drilling protocols, better un-
derstand the drilling sector and professionalise private
drilling enterprises in Nigeria, Uganda and the Sudan was
also drawn upon for the work.
The Generic Code of Practice was extensively reviewed
through consultations with UNICEF, XXXXXXX