Efforts to reduce this impact first began in 1969 when 15,000 acre feet (18,500 ML) of water were allocated to the Macquarie Marshes for wildlife preservation. The first time that this allocation was used was in November 1980. It was clear from monitoring of this release that 18, 500 ML per year were inadequate to provide conditions suitable for waterbirds, or protect the wetland values of the Marshes.

In the mid-1980s the Water Management Plan for the Macquarie Marshes 1986 (WMP) was developed, setting explicit rules governing the management of the Wildlife Allocation (WLA), as it became known. By now the WLA consisted of an annual entitlement of 50,000ML high security from Burrendong Dam. The 1986 WMP was reviewed and refined in the mid-1990s and resulted in the release of the Macquarie Marshes Water Management Plan 1996.

This new Plan increased the Wildlife Allocation (WLA) by 75,000 ML of general security (or irrigator security) water. Now in a full allocation year (100% allocation) the WLA totalled 125,000 ML. However even with this increase in allocation, delivery constraints still impacted on both the environmental and economic viability of the Macquarie Marshes.

The Year 2000 saw the introduction of the Water Management Act 2000 which stated Water Sharing Plans (WSPs) must be developed for all of the State’s major water sources. The Minister for Land and Water Conservation established River Management Committees State-wide, with the specified task of writing the Water Sharing Plans.

In the regulated Macquarie Cudgegong river system the River Management Committee representatives came from the key stakeholder groups within the Macquarie and Cudgegong valleys as well as government agencies and conservation interests. Macquarie Marshes Environmental Landholders Association was granted two positions on the Committee plus two alternate representatives.

This consultative process has seen the development of
what is now known as the Draft Water Sharing Plan for the regulated Macquarie Cudgegong River System. This Draft Plan still has to go through a public consultation period before being signed off in mid-2002. The Draft Plan again makes changes to the management of environmental flows to the Macquarie Marshes. However, until it is accepted and implemented by government, the details and rules of the 1996 Plan remain in place.

While the Draft Water Sharing Plan attempts to address the equitable sharing of water throughout the valley, it does not deal with other issues effecting management of environmental flows such as impediments on the floodplain (including levies and earthworks) and the discharge valve capacity of Burrendong Dam.

These issues were identified during the development of the Water Sharing Plan as serious restrictions to achieving the environmental outcomes necessary to maintain and enhance wetland health.
The Macquarie Floodplain Committee is in the process of developing yet another Plan with the aim of identifying floodplain impediments and making recommendations on their management such as reduction, removal or other strategies.

Unless improved flow regimes can be reinstated to the Macquarie Marshes the damaging impacts of constant flows (both low and medium) will continue to degrade this magnificent part of Australia. Flow heights of greater than 5,000ML/day are needed in the delivery of the WLA to reintroduce flow height variability which is vital for floodplain and wetland ecosystem functioning.

The steady rise, then peaking and tailing-off in flood regimes also needs to be restored when releases are made from the flood mitigation zone of Burrendong Dam. Contemporary management of these releases see flows delivered in a way that has little variability in flow heights. These releases are then subject to a rapid ‘shut-down’ which deprives the flood event of the tailing-off effect that is vital in reducing impacts such as bank slumping and the stranding of fish on the floodplain.

A new element included in the draft Water Sharing Plan sees the establishment of an ‘Environmental Flows Reference Group’ to advise the Department of Land and Water Conservation on the administration and management of environmental flows in the Macquarie and Cudgegong river systems. This group will consist of representatives who are either directly responsible for or directly impacted by environmental flow management.

In seeking membership for this group, nominees must display a thorough knowledge of the environmental needs of the valleys as well as the operational management of the system. This is seen as an exciting new step in environmental flow management and hopefully it will forge the way for other valleys to adopt a similar management strategy.

Governments cannot solve the problems facing rivers and wetlands alone. They must develop effective partnerships with local and regional communities, and maintain them where they exist. Many of the solutions to the problems now facing rivers and wetlands will come from cooperative community action. Government can provide broad guidance to communities, at the same time supporting them as they find new ways to manage rivers.

Water management remains the most critical issue for those charged with the on-ground management and future viability of the Macquarie Marshes. Macquarie Marshes landholders remain committed to being involved in water management issues including the review and monitoring process for the proposed Water Sharing Plan.

SUE JONES
is the Co-ordinator of the Macquarie Marshes Management Committee
www.macquariemarshes.com.au

Warnings From the Bush

By 2030, rainfall in the Macquarie Valley may be 3-10% lower, evaporation 3-10 % higher and mean annual flows in to the Marshes reduced by 11-32 % …Climate change is likely to cause a decline in the wetland’s vegetation by up to 40%, and fewer numbers and less frequent breeding of waterbirds and other wetland animals, such as turtles and frogs….it is not clear if these species will find other places to breed as the MM is one of the only wetlands in the Murray Darling Basin (Hassell and Associates, 1998 from Warnings From the Bush, Climate Action Network Australia, 2002.)