Civil Engineering Reference
In-Depth Information
Tennessee Valley Authority case study (see p. 169) illustrates its policy for
operating the Tennessee River and reservoir system to meet multiple needs.
Investing in upgrading ageing infrastructure
Ageing urban and irrigation distribution systems in particular can be
revitalised to reduce losses and improve operational efficiency. This can
be particularly important in areas where demand for water exceeds supply
as an alternative to building new dams, or to allow more water to be left
for environmental and non-consumptive human uses without impacting
on economic production. Case studies addressing ageing infrastructure are
presented later in this chapter.
Direct regulation of water extraction
Individual water users can be required to comply with limits on the volume,
rate and timing of extraction, usually through licensing arrangements.
Licensing of water extraction requires that laws be in place that prohibit
extraction of water except under an issued water licence, and that these
laws are enforced. Such water licences can be issued to persons, companies,
community groups and organisations, cities and towns, and even government
agencies. The laws can provide for exemption from licensing or volumetric
limitations in specific circumstances, e.g. for small-scale domestic drinking
and sanitation or for firefighting. The integrity of the water licensing
arrangement as a whole is dependent on there being no water extraction
outside of the licensing system that could defeat its purpose, for example
through large exemptions or poor enforcement.
Water licences can be defined in many different ways. They can be for a
fixed term or perpetual. They can be restricted to extraction from one location
or can be movable. Ownership can be fixed to the applicant or transferable.
Limits and conditions on extraction can be defined by volume, purpose, rate,
timing, authorised infrastructure or other parameters.
Water licensing is not always practical or cost effective to implement. As
an alternative to water licensing, water extraction can be regulated through
restrictions imposed generally or in an area, on a permanent or periodic basis,
on such things as pump size, irrigated area and crop types, pump timing, etc.
Such restrictions are proclaimed, publicised, explained and enforced under
legislative powers.
Water resource plans may define the maximum volume of water able to be
taken per season or year or during particular circumstances under licences as
a whole, groups of licences of a kind, individual water licences or for water
users in a particular area where there is no licensing system. These limits
are used to preserve water for non-consumptive benefits (ecology condition,
recreational water use, etc.), and for sharing of water between consumptive
