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communication difficulty between some stations and
those responsible for the water supply. Some remote
stations (one or more water tanks) can be in isolated
places, with difficult access, and often do not have
power supply. On the other hand, the distance
between the station and the responsible entity can be
huge. For the responsible entity to have reliable and
up-to-date information about each water tank, as
well as the amount and quality of the water, it is
necessary to implement a system that answers these
questions.
The work presented in this paper was guided by
the design and implementation of an information
system to monitor some parameters related to water
supply.
This work has been developed under an
academic research project driven by undergraduate
students in collaboration with water supplier.
In order to model the information system
developed, an object-oriented approach was
followed, namely the UML - Unified Modelling
Language (Booch et al., 1999).
This paper is structured as follows. The
following section describes the problem. An
overview of the main requirements for the system
developed is presented in section three, and our
prototype is presented in section four Finally, we
will summarise our results and make a brief
reference to some topics for future work.
2 THE PROBLEM
In some cases water quality monitoring is done by
an individual that visits each water tank and takes
samples. Often these water tanks are in places with
difficult access, making the procedure difficult and
expensive and results unreliable.
In this case we have just about one hundred
water tanks dispersed in an area of approximately
1000 Km2. Obtaining samples of all water tanks
manually, analysing each sample and making
changes in water quality control, if needed, is a slow
and expensive task that may not guarantees reliable
results. Sampling results obtained with a big delay
doesn’t allow for making corrections in time. One
way to minimize this problem is through an
information system that allows remote monitoring of
some water properties.
Real time remote sensing of the water
parameters provides information that enables
effective monitoring and control of water quality at
low cost. All this information is periodically
transmitted to the head office and stored in a
database. The system may be equipped with decision
support algorithms and applied to identifying and
controlling changes in each water tank’s properties
that are significant in improving water quality. The
consultation and administration of the data will be
carried out through the Internet.
The information system will allow real time
monitoring and detection of some atypical situations.
With real time information, it will be possible to
prevent the supply imperfections of impure water to
the populations, as well as to report on and
statistically analyse the water levels.
We have split this project into two different
stages. In stage 1 we aim to remotely monitoring the
water and pH levels in each tank. In the second stage
the main goal is to enlarge the range of controlling
fields, such as chlorine.
Having a continuous monitoring of the water
properties of each water tanks it is possible to act
much more quickly and with better results.
3 OVERVIEW OF SYSTEM
REQUIREMENTS
3.1 Main System Requirements
The developed system should deliver the required
functionality and performance to the user and should
be maintainable, dependable and usable. In the
remote monitoring environment, it is crucial to
provide fast, reliable and on-time responses when
dealing with unexpected events. These are the most
important high-level and general requirements to be
fulfilled by the system.
System requirements are usually divided into
two classes – functional requirements and non-
functional requirements. The first describe what the
system should do and is perceptible to the user,
while the second describe constraints on how the
functional requirements are implemented, and is not
necessarily perceptible to the user (Sommerville and
Sawyer, 1997).
3.2 Functional Requirements
Remote configuration. Through this requirement it
is possible to configure some parameters of the
stations remotely, namely the frequency sampling of
each sensor.
Event Notification. This feature is considered a
very important requirement, because it allows
notification in real-time if disruptive events occur in
one station, e.g. if the water level of one tank falls
below the set-point, the system sends an alert to the
person in charge of the maintenance.
WATER SUPPLY REMOTE MONITORING SYSTEM: A CASE STUDY
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