Geography Reference
In-Depth Information
be highly intermittent. These are identified in
Table 10.5.
In making demand forecasts for the major
component of water use, domestic demand, the
regulator has required companies to express
demand as a demand for water per person, usually
referred to as pcc (
per capita
consumption) by the
water industry, and herein lies an unnecessary
complexity of marked geographical significance.
Water is supplied to households, bills are for
households, the census deals with households, and
any remotely sensed data is attributed to
households and not to individuals. We have never
effectively monitored a representative individual
and probably never will. Therefore there is a
considerable body of research devoted to linking
geographical expertise in census information
manipulation concerned with the individual
make-up of households to the water use of these
households. Such work draws on microsimulation
and has been reported in Clarke
et al
. 1997.
Unmetered demand is measured in two
fundamental ways: by area meters; and by domestic
consumption monitors. Both bring the water
manager to confront the diversity and complexity
of populations, industry and urban structure. An
area meter is simply that: a meter on the potable
water distribution system, post treatment works,
which measures water delivered to an area.
Interpretation of the raw data from an area meter
presents many challenges:
Table 10.5
Components and possible amplitudes of true and resource demand.
Figure 10.2
Graphical
representation of output from
an area meter that measures
the flow of water to a small
area having a mix of industry
and domestic users. The
minimum flow, less an
allowance for legal use at
night, is the nightline. By
subtracting metered
industrial use of water the
area leakage can be
identified. Readers will
appreciate that this is a
simplified outline of the
leakage estimation
procedure.
