Dealing with salinity in Wheatbelt Valleys - Department of Water

CASE STUDY - TOOLIBIN LAKE AND CATCHMENT
INTRODUCTION
In 1996 a group of scientists and land managers met
to discuss “A Vision for a Sustainable Future: A
Greenprint for the Wheatbelt”. The key headings
used below, including those for guiding principles,
were developed at that workshop. This case study
was intended as one of several to be included in a
book arising from the workshop. The book was
never published, and this case study has not been
updated since 1998. While we have learnt much
since then – including that the period over which we
thought engineering intervention would be required
was much too optimistic – the ideas and comments
arising from the case study are still relevant today.
Therefore, the paper has been published here with
only minor amendments.
Ken Wallace 1
PERTH
WESTERN
AUSTRALIA
Toolibin
Lake
Wallace
THE LAKE AND CATCHMENT Figure 1: Location of Toolibin Lake (figure adapted
Toolibin Lake nature reserve contains the most
important remaining representative of a once
widespread natural community. However, without
intense management the Lake will become highly
saline within 10 years.
The Lake and its catchment lie at the head of the
Arthur River which in turn drains into the Blackwood
River (Figure 1), a major river of South-western
Australia. The catchment is some 49,000 ha in area.
Toolibin Lake, with a surface area of about 300 ha, is
part of a nature reserve held under management
order by the Conservation Commission of Western
Australia. Nature reserves are managed by the
Department of Conservation and Land Management
(CALM) on behalf of the Commission.
Farming based on cereals, mainly wheat, and sheep
production for meat and wool, are the primary land
uses in the catchment. There are some 40 familyowned
landholdings in the catchment. Nature
conservation and associated passive recreation and
education are also land uses. Toolibin Lake is a focus
for these activities.
1 Department of Conservation and Land Management, Narrogin
– 1 –
from The Status and Future of Lake Toolibin as a
Wildlife Reserve, a report prepared by the Northern
Arthur River Wetlands Committee, May 1987, and
published by the Water Authority of Western
Australia
Seasonally flooded, fresh water wetlands with
extensive sheoak (Casuarina obesa) and melaleuca
(Melaleuca spp) across their floors were once
common in agricultural lands east of the Darling
Scarp. These wetlands, with their fresh water and
excellent breeding habitat, were very important for
waterbirds. All have become saline to some degree,
and Toolibin is now the only Lake that still has both
reasonable water quality and extensive living stands
of sheoak and melaleuca. While water quality in
Toolibin has declined, during wetter than average
winters the Lake is sufficiently fresh to attract a wide
range of waterbirds including those that require fresh
water for breeding. Those wishing to explore the
relationships between salinity and biota should read
papers by Halse (1987, 1988, 1993) and Sanders
(1991), and the report on salinity in Western