Dealing with salinity in Wheatbelt Valleys - Department of Water

Secondly, there is a set of practical management
actions that it is predicted will halt, and then reverse,
salinisation of the catchment. These actions will take
some years to implement and decades to have a
strong, positive effect on the catchment’s hydrology.
If successful, these actions will allow the emergency
actions instituted for the Lake and its environs to be
discontinued. When this point is reached, the Lake
will, provided certain biophysical criteria are met,
have been sustainably recovered. In the same
process, the deterioration of the agricultural values
of the catchment will have been stopped, and, in
some cases, recovered. Under this scenario the
long-term savings achieved by better protecting the
agricultural production values of the catchment will
far outweigh any costs.
Emergency and long term actions are described in
Table 1. Communication and integration actions,
which cut across both short and long term actions,
are shown as a separate category within the table.
It must be stressed that significant revegetation of
the catchment with perennial, woody vegetation is
essential to achieve a sustainable recovery of the
Lake and its catchment. Without this, it will be
impracticable to restore benign hydrological
conditions within the catchment.
Part of this revegetation has occurred and is
achieving a range of benefits including stock shelter,
erosion control, aesthetics, local control of
groundwaters, nature conservation goals and forage
for stock. However, the current speed and extent of
revegetation will not be sufficient to recover the
Lake and catchment without significant external
resources, or a commercial woody crop, or both.
Thus an important challenge being addressed at
Toolibin is that of developing agroforestry systems
that achieve the goals of all catchment land
managers. While work in this area has been slow
starting, it is currently gaining momentum. The
Wickepin Shire (within which Toolibin occurs) is one
of the first six centres where the development of a
eucalyptus oil industry based on mallees (a multistemmed,
lignotuberous form of Eucalyptus spp) is
being explored. To date (September 1998)
164,500 oil mallees have been planted in the
catchment. Limited harvesting has occurred,
however, this will greatly increase. Whether this will
develop into a viable industry will depend on:
• sufficient local farmer support;
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Wallace
• opening up of potentially huge markets for use
of cineole, for example, as a solvent;
• cheaper means of harvesting and extraction;
• genetic improvement of current stock.
All these constraints can be overcome. However,
there is an urgent need to develop further potential
industries based on woody vegetation. Toolibin is a
vital flagship for developing and promoting profitable
and sustainable agricultural systems that utilise
woody vegetation.
Action and the Guiding Principles for
Integrated Management
The following comments are my perspective on how
all catchment land managers - Government and
private - are performing in comparison with the aims
of the guiding principles for integrated management
developed at a workshop in 1996 (outputs were not
published).
Learn to live with this country and its environment
Catchment land managers recognise that the
hydrological cycle has been pushed into a form
harmful to both conservation and production, and
most are acting on this knowledge. To this degree
we are learning to live with this country and its
environment. However, amongst land managers
there is uneven knowledge of landscape processes
and what we must do to live within the natural
system. Even our general understanding of
hydrological cycles is imperfect. As will be covered
below, general understanding of energy and nutrient
processes is poor. Our current system of coping
with soil infertility depends on large inputs of
fertilisers, and general knowledge of the longer
natural cycles (for example, plant regeneration) and
the significance of erratic, episodic events, such as
fires and cyclones, is poor. We are learning, but we
have a long way to go. Some of the necessary
changes in knowledge will require more than one
generation to establish.
Maintain diversity and keep our options open
By protecting remnant native vegetation better, and
acting to recover the Lake, land managers are aiming
to protect diversity within the natural system.
Actions that have been taken include:
• fencing remnant vegetation;