Summary
Background
The importance of proper monitoring
and maintenance of water supply boreholes and irrigation
tubewells was highlighted during an ODA sponsored project, international
survey and conference
held in 1990. (ODA projects R4428/R4582/D044). This trend has
been reinforced by the UK and
USA water industries' recent decisions to commission the preparation
of guide-lines for the
development of practically and economically sound borehole monitoring
and diagnosis, operation
and maintenance, and rehabilitation, strategies.
Many Third World countries depend
on potable water and irrigation water supplies from
groundwater resources via boreholes/tubewells. Yet with inadequate
or inappropriate monitoring
and maintenance too many of these wells operate inefficiently
or have been abandoned.
Rehabilitation if attempted was often on a `suck-it-and-see'
basis and frequently failed. While
such a situation exists in many parts of the developed world
also, it must be regarded as
particularly serious in developing countries where weak economies
could well do without the
added strain of supporting inefficient systems or where failure
can simply mean going without.
Cost effective, functional and sustainable groundwater abstraction
strategies need to be
established. It is believed that money spent in the establishment
of such practices will be repaid
many times over in terms of savings in annual groundwater pumping
costs and in capital
replacement costs. The human benefits in terms of social needs,
health and food production are
of even greater proportions.
Whilst many developing countries
themselves recognise the weakness in their groundwater
abstraction strategies, they often do not have the resources
to change. It is not only finance that is
required. Institutions and infrastructure need to be in place.
To help establish and then run these,
training in technology and management is also required. At each
stage and in each component
the cost effectiveness of the measures proposed needs to be assessed.
This is important for both
international aid agencies in supporting projects and national
governments in the prudent
allocation of scarce funds.
Experience suggests that whilst
cost-benefit analysis is widely talked about and is being
increasingly applied, application to specific disciplines requires
considerable input to establish the
scope of a system, its consequences and the key economic factors.
It would not be practical or
good use of resources if every organisation had to go through
the same development stages.
Objectives
Immediate
A project report in which the
methodology is presented and explained.
Intermediate
A report on the developed methodology
which is widely disseminated.
The rapid acceptance and utilisation of the developed methodology.
Wider objectives
The establishment of practically
and economically sound and integrated management strategies
for groundwater abstraction systems.
leading to:
More efficient and reliable water
supplies from boreholes, with reduced operating costs and
reduced demand for capital /replacement projects.
and with:
Benefits passed onto public health,
agriculture and food production.
Methodology
A methodology has been developed
from an evaluation of groundwater engineering experience,
from a review of technical, economic and management literature
and from consultations with
potential users in the UK and overseas. General features of the
methodology defined at the outset
were that, for it to be readily usable and useful, it had to
be:
- relatively simple and easy to
apply by a range of professional disciplines;
- flexible in relation to the
wide range of hydrogeological and groundwater engineering
circumstances likely to be encountered;
- flexible in relation to the
amount and quality of data available;
- flexible in relation to the
users needs and circumstances
There are two main steps in the
assessment of the cost-effectiveness of m & m. These are
an
internal technical/monetary assessment, concerning the management
of the groundwater
abstraction system itself, and external factors relating to water
use, water users and the
environment in which water abstraction is taking place.
The method makes two basic assumptions:
(i) that there are three main
components which are important in the assessment of cost effectiveness
- these are costs of management options,frequencies with which
costs are incurred and well performance over time;
(ii) that effective m & m
fulfills its objective of the maintenance of a standard of service
and that the costs are incurred in doing so.
The approach taken in the development
of the method, assumes that increasing levels of
monitoring enable, firstly and most importantly, well performance
to be analysed, then well
condition to be assessed, and then the process causing well condition
to be identified. As a result
of monitoring, appropriate maintenance strategies may then be
selected. Each element of the
approach is described below.
- The internal assessment allows
for m & m to be assessed for several classifications of well,
i.e. for different aquifer, well and pump types. This recognises
that some classifications will
regularly present less operation and maintenance problems than
others.
- Monitoring enables the performance
of the well system to be assessed, early indicators of any
deterioration in performance to be identified, and where appropriate
the need for early
corrective maintenance to be identified. The monitoring of well
performance is the primary and
simplest level of monitoring.
- Once a decline in well performance
has been diagnosed, monitoring enables the condition of
the components of the groundwater abstraction system to be assessed
in order to identify the
extent and location of the problem within the abstraction system.
Corrective maintenance may
then be carried out.
- A comprehensive level of m &
m allows processes which cause deterioration in well
component condition and well performance to be identified and
appropriate preventative
maintenance to be carried out to reduce the impact of the processes
upon future well
performance.
- Through analysis of the information
gained, monitoring enables the use of risk assessment
techniques, which estimate the risk of deterioration of well
performance or well component
failures for given aquifer characteristics and well components.
The principle of risk
assessment is one that has been developed in the evaluation of
maintenance schedules for
water delivery systems and in other supply industries.
- The analysis of performance,
condition, and process for different classifications of well
may
enable modifications to the design, construction (including material
selection) and
management of future groundwater abstraction systems to be made.
- Whilst given strategies for
m & m will produce benefits such as those shown above, there
will
be associated monetary costs attached to them. A m & m strategy
will incur additional costs
but is also likely to lead to savings due to a reduction in the
frequency of other costs, such as
those for well rehabilitation, pump replacement and emergency
action following well failure.
Therefore, different strategies will have different costs and
benefits reflecting differences in
frequency of occurrence, well operation and other well management
events.
The assessment of cost-effectiveness
can be carried out in two ways. One is to take into account
only the anticipated costs 'with' and 'without' m & m (or
for different levels of m & m), in order to
show simply whether it is more or less expensive to monitor and
maintain than not to (or which is
the cheaper of two different m & m strategies). This level
of assessment implies a change in the
performance of the well through the changes in frequency with
which costs of other well
management events are incurred (such as well rehabilitation or
pump replacement). It does not
take directly into account the actual performance of the well.
Therefore, another way is to relate
the costs of well management to well performance for 'with' and
'without' m & m (or for different
levels of maintenance).
The internal assessment examines
only the direct monetary costs and benefits of alternative m
&
m strategies for groundwater abstraction systems. The benefits
of a higher level of m & m are a
sustained well performance level and a reduction in the risk
of system failure and the related
costs of disruption, emergency response and premature capital
replacement. The outcome of the
internal assessment is an estimate of net present value of the
m & m strategy. However, this
estimate is likely to represent only a minimum order of the value
of m & m. In many situations the
estimate of m & m benefits is likely to undervalue the benefit
to users, suppliers and regulators of
a reliable, safe, and resource-efficient system. For example,
the internal assessment recognises
that system failure may result in extra costs of emergency supplies.
The impact on user welfare
of a disrupted and unpredictable water supply, however, is not
included in the internal
assessment. In some cases, these users may be farmers or manufacturers
who suffer loss of
production as a result of unreliability in supply.
For this reason, an external
assessment is included, which reflects the environment in which
the
groundwater system operates. This assessment recognises that
agents (users or suppliers) may
derive benefits (and costs) over and above those which can be
measured in monetary values,
and that these agents may be willing to commit extra capital
and recurrent expenditure in order to
secure these non-monetary, less tangible, benefits.
The external assessment is compatible
with the principle of a 'predefined standard of service'. For
example, water of a specified quality should be made available
to users of a given type in given
quantities with a given probability of uninterrupted supply.
Where such standards have been
specified, the best strategy for m & m is that which delivers
the standards of service at minimum
cost. In many cases, however, standards of service are not adequately
defined and they are a
variable in the formulation of a water supply (and m & m)
strategy.
Furthermore, the standards of
service are likely to vary according to local circumstances and
practices, which are socially, economically and politically defined.
The external assessment
attempts to elicit implied, locally relevant standards of service,
and thereby the extent to which the
satisfaction of these could be used to justify part, or indeed
all, of the additional costs of m & m.
The elements included in the
external assessment are:
- User Category
- User Population
- User Confidence
- Alternative sources
- Environmental Impacts
It is recognised that these external
factors are important in the formulation of an appropriate m
&
m strategy and that decision criteria should extend beyond cost
benefit to include elements of
standards of service. In broad terms, this requires water suppliers,
preferably as a result of
consultation, to determine the proportion of m & m costs
which should be offset against
particular standards of service. In most cases, this will have
the effect of reducing the level of extra costs of m & m,
thereby increasing the benefit:cost ratio and the perceived value-added
of m & m.
Use and users
The method is appropriate for
people who are closely involved with the day-to-day management
of groundwater abstraction systems, for people who are involved
in the planning and
implementation of water supply systems and for those who are
involved at the project feasibility
and financing level.
It is anticipated that there
will be three main types of user:
(i) Well management or monitoring/maintenance
organisations or individuals with adequate
data who will be able to fully utilise the method.
(ii) Well management or monitoring/maintenance
organisations or individuals with inadequate
data who can use the method to gain crude estimates of the likely
costs and benefits of
various options. These first indicators may well often demonstrate
the need for a m & m
strategy and initiate monitoring and data collection. In this
respect attempts have been made
to provide guidance on data needs, sources, collection and compilation.
(iii) Planners who wish to evaluate
all aspects of current or potential groundwater resource
development/supply projects.
Following consultations with
potential users of the method, initial thoughts that lack of
detailed
data may be a concern were confirmed. Therefore, two versions
of the method have been
developed. One considers detailed cost and well performance data
and one offers assistance to
users in the selection and definition of data for analysis.
The method has been developed
on Lotus 123 spreadsheets so that it may be compatible with
most other spreadsheets used world-wide. In all cases the user
goes through a three stage
process: guided data input to a structured spreadsheet file,
selected data analysis and a choice of
result presentation.
The proposed method is designed
so that it can be used as either a stand-alone tool or as part
of
an integrated water management system. It is intended to be flexible
so that not only m & m
strategies may be assessed but also that any groundwater abstraction
option (such as pumping
regimes) may be analysed for cost-effectiveness.
The approach is more suitable
to deep wells, with motorised pumps, than to shallow wells which
use hand pumps. The method may be used for the latter case, although
the emphasis of the
analysis will be upon the costs 'with' and 'without' maintenance,
since the issue of well
performance and, hence, operating costs is much less crucial.
Future action
Immediate
This report has been circulated
to 50 organisations both in the UK and overseas for evaluation.
Intermediate
It is proposed that a second
phase to this project should be a full and detailed trial application
and
adaption where necessary of the proposed methodology by appropriate
organisations. In the UK
it is hoped that several of the major water plc's which have
significant numbers boreholes will
undertake a full cost-benefit analysis of alternative monitoring
and maintenance strategies, using
the prepared methodology. In developing countries it is hoped
that the development of monitoring
and maintenance strategies could form part of existing or new
groundwater projects and
developments, in which the cost-effectiveness/benefit evaluation
of alternative strategies would
be an important component.
We would be pleased to hear from
any organisation or agency in the process of reviewing an
existing or developing/planning to develop a new, monitoring
and maintenance strategy for
groundwater abstraction systems, where they think that this work
could make a useful
contribution.
The project work is summarised
in the following paper:
Sutherland, D C, Howsam, P
and Morris, J (1996).
Cost-effective monitoring and maintenance
strategies for groundwater abstraction. Journal of Water
Supply, Research and Technology -AQUA,
45 (2), 49-56. |
