Dealing with salinity in Wheatbelt Valleys - Department of Water

Pannell
ECONOMICS, SOCIETY AND
ENVIRONMENT
As noted above, economic development objectives
provided much of the impetus for clearing almost
all of the WA Wheatbelt, starting with the valley
floors, over the course of the twentieth century.
However, social objectives played a key role as
well, particularly the objective of providing for
returned servicemen following each of the World
Wars (Beresford et al. 2001). It is hard to
distinguish between economic and social
objectives in that context. Environmental
objectives did not appear to be high on the agenda
until late in the Century, but this has changed
radically. Indeed, an environmental issue
(commercial harvesting of logs from old-growth
forests) is credited with contributing substantially
to the change of State Government in Western
Australia in 2001.
The old-growth forest issue involves difficult and
sometimes messy tradeoffs between
environmental, social and economic outcomes.
Increasingly, salinity will do so as well. Here are
three examples which illustrate the shape of things
to come.
1. Disposal of saline water pumped from under
towns.
In towns located on valley floors, such as Merredin
and Katanning, prevention of salinity damage will
require engineering works, particularly pumping.
Disposal of the water poses problems. Use of
evaporation basins will be expensive enough in
some cases to tip the economic equation away
from salinity prevention. Disposal of the water in
a creek or river may be the only way it can be
made cheap enough to be worthwhile protecting
town infrastructure, but this clearly requires a
judgement that the damage to the creek or river
system is not excessive. Another proposal is to
use the pumped water to irrigate salt-tolerant
plants, but the feasibility of this would need further
investigation.
2. Social impacts from land use change
Salinity prevention requires massive land use
change. Few people have appreciated how far
reaching will be the consequences if we are
successful in achieving change on the scale needed.
The experience of blue gums on the south coast
reveals that social impacts will be prominent
among the concerns of local communities. There
are grounds to hope that many of the social
impacts from new perennials in the Wheatbelt will
– 2 –
be positive, but this may require government
intervention to curb some of the desired activities
of business interests. On the other hand, the
involvement of such business interests seems
essential to finance perennial establishment over a
large scale.
3. Budget limits and the need for prioritisation
Protecting assets from salinity is expensive. There
are many assets at risk, and there will never be
enough public money available to protect them all.
Hard decisions will have to be made to prioritise
the assets under threat. Is this wetland more or
less important to protect than that town?
The sort of trade-offs involved in these examples
are the stuff of politics. They will inflame
communities, especially those groups who feel
they are losers, but they may also act as catalysts
for community action and consensus.
ECONOMIC COSTS AND BENEFITS OF
SALINITY MANAGEMENT
Until fairly recently, economists considering salinity
most commonly attempted to estimate “the cost
of salinity”, usually in comparison to a mythical and
unachievable scenario of zero salinity. “The cost
of salinity” by itself is a concept of almost no
practical value (Van Bueren & Pannell 1999;
Bathgate & Pannell 2002). Indeed, the large
estimated costs have probably done more to
mislead thinking about salinity than to improve it.
It is better instead to focus on the costs and
benefits of specific management strategies,
allowing for realistic levels of effectiveness. As
much as possible, that will be the perspective
taken here.
Agriculture
Salinity management practices for agriculture are
considered here in three categories: prevention,
living with salinity (adaptation), and repair.
Prevention of salinity
The term “prevention” is used here to mean
avoidance (in part or in full) of a further worsening
in salinity. It is not intended to imply a reduction in
current levels of salinity. The scales of treatments
recommended by hydrologists for preventing the
various impacts of dryland salinity are daunting,
particularly in large wheatbelt valleys. In recent
years, we have lost earlier hopes that large-scale