B G Dyer
SUMMARYOperating procedures for regulated rivers are generally not prescriptive. They exist as guidelines and constraints and the river operator has some flexibility within these. As such there is considerable potential for those involved in management of these rivers to work with the river operator to achieve widespread small-scale improvements. The key to achieving improvement is for those involved in river management to understand how the river is operated (learn the guidelines and constraints that exist) and provide the operator with information that they can apply directly.Australia is a dry continent with highly variable climate, directly reflected in the scarcity of the nation’s water resources. The result of this has been widespread construction of storages and the regulation of nearly all of the major rivers within the Murray-Darling Basin. It is therefore essential in river management to recognise that for many of our rivers we are no longer dealing with a natural system and that it is not practical to revert to a natural system. However, the way in which these regulated rivers are managed will have direct impacts on the riverine environment.
The management of regulated rivers is inherently linked to the operation of these rivers for water supply. By changing the way in which the rivers are operated, while continuing to meet the demands placed on the rivers for water supply, significant benefits can be gained for the riverine ecosystem. In many cases the major ongoing cost associated with achieving these gains is increased effort from the river operators.
It is now generally recognised that many regulated rivers are being managed at a less than optimal level in terms of the impact on the riverine environment, with some people questioning whether the current situation is sustainable. As such, there is a need for change. There are three ways this change can be brought about through policy change, community involvement and working with river operators. Each is suited to a different scenario, each has advantages and disadvantages. Some of the issues associated with these are outlined in the sections below.
Changing policies is often seen as the best method of achieving longterm broadscale change in the way rivers are operated. In considering major policy initiatives, such as the cap on diversion in the Murray-Darling Basin, it is worth noting some of the practical issues.
For policy change to be effective, it is essential that there is commitment by the organisations responsible for river operation to implement the new policy. Some policies that are prepared with the best of intentions, and appear to provide a major step forward, fail to deliver. An example is the 100 gigalitre allocation for the Barmah Millewa Forest provided for maintaining wetlands and partial flooding of the forest within areas protected by small scale works. While this policy received in principle agreement from the Murray-Darling Basin Ministerial Council in June 1993, no water was released to water the forest until 100 gigalitres was released in 1998 – a five year delay.
Implementing major policy decisions or changes requires considerable energy and effort. An example is the cap on diversions in the Murray-Darling Basin restricting diversions to 1994 levels of development. This was initially agreed to by the Murray-Darling Basin Ministerial Council in June 1995 and formally implemented from 1st July 1997. A key component of monitoring compliance with the cap is the development of computer models that use the actual climatic and hydrologic conditions for a year to determine what the water usage would have been in that year with 1994 levels of development. Development of these models has required major effort and time commitment, in most cases an order of magnitude greater than that originally predicted. The practical implementation of the cap has been delayed by the lack of resources made available to those responsible for delivering the desired outcome.
These examples show that policy changes are suitable for major initiatives that will benefit river health, but to be successful they must have support and be adequately resourced to ensure that the policy change is reflected in changes in river operation.
In 1996 the MDBC released approximately 30% of the water from Hume dam for safety reasons. This resulted in extended periods of flooding along the River Murray with subsequent compensation payments. One of the outcomes of this event has been an extensive community involvement exercise, involving representatives covering the range from floodplain landholders to irrigators to environmentalists. The objective of this group was to develop recommendations to the Murray-Darling Basin Ministerial Council regarding better ways to operate the upper Murray storages. This process is expected to be finalised in early 1999.
The community involvement process has been regarded as a very positive exercise and has increased understanding among both the community and the government agencies involved. The negative aspect is that the process has taken a long time and been expensive both financially and in the time of key staff. The overall effectiveness of this exercise is yet to be determined but the options paper1 prepared by the group highlights significant issues for which it has not been possible to achieve consensus among the diverse range of groups represented.
The long time frame and high costs associated with running a community involvement process limits the applicability of this method in achieving change in river management and thus, benefits for the river. The positive aspect is that where a change is agreed to, it has widespread community support and understanding and is therefore more likely to achieve acceptance.
The major regulated river systems in the basin are highly complex with multiple storages, distributed demands, and long flow travel times. Superimposed on this is high climatic variability. Consequently operating procedures are typically defined as ‘guidelines’ and ‘constraints’ and rely on the experience and common sense of the river operator to ensure that a suitable outcome is achieved. Therefore, the river operator has considerable power to manage the river in ways that are conducive to an improved riverine environment.
The focus of this paper is that by working with the river operator, within the constraints they are subject to, it is often possible to develop simple, low cost solutions to localised issues. It is the author’s view that this option is under-utilised.
The key to any regulated river system is the river operator. In considering the role of the river operator, it is useful first to dispel a few myths. River operators are not:
While these may sound extreme they are not uncommon labels. Perhaps a more typical view of a river operator is of the tap turner, where the job involves doing a few sums to decide how much water to release from storage. The role of the river operator is far more involved than this. The following gives a brief insight to the role of the river operator.
The role of the river operator comes into sharp focus during major events, most typically floods and droughts, but is generally overlooked for the remainder of the time. This is in accord with the Pareto principle – 80% of interest is focussed on less than 20% of the job. This bias in the focus means that many opportunities for improved river management are overlooked.
As outlined above, the river operator does not generally have a set of prescriptive rules that have to be applied, rather they operate within a set of guidelines and constraints. This means that there is flexibility in operation. By taking advantage of this flexibility, significant gains may be made in terms of managing the river to achieve improvements in the health and sustainability of the riverine ecosystem. A further point to note is that the best person to change the guidelines is the river operator. The operator is working within the system, is generally seen as the expert for that system, and is therefore much more able to have a change accepted and adopted quickly.
There is a two-fold message in this for people involved in river management on regulated rivers:
The key to this is to first obtain a general understanding of the overall system – how multiple storages are operated within a single system, how annual water allocations for the system are determined, where the major demand sites are, what the seasonality of these demands are. Understanding the system will take time but is essential background to understanding specific operating criteria.
Developing an understanding of specific operations for a reach of river will involve spending time with the river operator and discussing why certain operations occur, what are the guidelines and constraints related to that operation. Many of the constraints will be direct results of the system structure – hence the need to understand the system.
In many cases this will require writing a report specifically for the operator. The greatest success will occur if the operator is involved in framing the report structure. Some successful applications of this process are presented in the following case studies.
A point to note is that as the organisations responsible for river operation become more commercially oriented, the ability for river operators to be actively involved in and pursue changes to operating procedures for river management objectives will decrease. This means that the change will need to be championed by someone else and presented to the river operator in a user-friendly and applicable manner.
The above discussion outlines how the river operator can be involved in improving river management. What must be stressed is that river operators are subject to pressure from a wide range of interests. Many of these pressures relate to water supply rather than river management.
As a general statement, pressures brought to bear on river operators to change operation to advantage water users are an order of magnitude greater than those related to river management. This is fundamentally due to water users being able to place an economic value on the change in operation. It is not unusual for water users to enlist the support of their local member to support their request.
In many cases the change in operations to assist a water user occurs at a cost to the riverine environment. Examples of this include:
The message from this is clear:
The MDBC is responsible for releases from Menindee Lakes on the Lower Darling River. A key feature on this section of river is the weirs used to maintain pools for pumping. These weirs are rock fill structures and were constructed with minimal consideration for fish passage, although fish passage can occur at high flows when the weirs are drowned. The problem is that at moderate flows the fish attempt to traverse the weir and are easily caught. Some reports indicate that this can become a fish harvesting exercise (Mike Arandt, NSW Department of Land and Water Conservation, pers. com. 1996).
This issue was brought to the attention of the MDBC by various people. The key information required by the river operators was the flow at which native fish passage was considered to be reasonable and the flow range where native fish will attempt passage but be highly vulnerable in the process. Once this information was provided, the operation of this section of river was modified to maximise the potential for fish passage and minimise the period where fish will attempt passage but be highly vulnerable in the process.
The Barmah Millewa Forest has been a major focus for research into how river regulation is affecting wetland ecosystems. The result of this has been major management plans and the specific allocation of 100 gigalitres of water for the forest. Despite the major research effort the forest was still subject to regular unseasonal flooding of wetlands, in particular along the Edward River. Thus the forest received too much flooding of low-lying wetlands and insufficient flooding of higher ground.
The problems of water management in the forest, in-particular the unseasonal flooding of wetlands, were raised directly with the river operators by local staff from NSW State Forests and the Victorian Department of Conservation and Natural Resources. A key to obtaining an understanding of the problems was the forest agencies taking the river operators on a tour of the forest to observe the problems. The outcome of these tours and discussions was the distillation of three primary problems:
The issue of communication was resolved by both the river operators and the foresters making a much greater effort to keep the other informed of what was happening and any issues that could be foreseen. This was the first and most important step as it allowed both parties to develop an understanding of the other’s job, with its associated responsibilities and constraints.
The reduction in river capacity was investigated and confirmed by the MDBC. As a result of this, operating guidelines were changed to reflect a maximum regulated river level through the forest rather than the previous concept of a maximum regulated flow. This recognises that it is water level not flow that governs flooding and that the river is a dynamic system that changes with time. By defining a maximum water level at a key site in the Forest operators can regularly review the steady state flow required to reach that level and then operate with that flow as the maximum regulated release.
The solution to the flooding of the redgums along the Edward River was resolved over several years. The initial step was to resume use of a regulator where the Edward leaves the Murray to regulate flows in the Edward River to the minimum required for water supply purposes. This resulted in an immediate reduction in water levels along the Edward River.
Following this, a NSW Department of Land and Water Conservation river operator carried out a survey of all effluent streams from the Edward and sites where overbank flow occurred. This resulted in a new maximum capacity for the Edward River being incorporated into the river operations guidelines. At this flow rate, overbank flow did not occur but effluent streams still carried water out to wetlands, keeping them continuously inundated.
The next stage was to investigate all of the effluent streams and construct temporary block banks across them to allow the wetlands to undergo a drying cycle. The current phase of the project involves the construction of small regulators to replace the blockbanks. These will allow the wetlands to be connected to the river during the winter-spring period (the design allows for fish passage when the regulators are open) and to dry out over the summer-autumn period. This will mimic the natural wetting and drying cycle of the wetlands.
The key to the success of the changes in the Barmah Millewa forest lay in the communication between the river operators and the foresters. Once a common understanding of the problem was reached the development of a solution was relatively simple. The key to achieving a common understanding of the problems and potential solutions was spending several days in the forest looking at the problems and sharing ideas and understanding. Without this a solution would not have occurred.
While a solution has been found for some issues, others remain intractable, eg the un-seasonal flooding due to ‘rain rejections’ (where irrigation demand reduces suddenly due to rainfall and the river flow rises rapidly, often compounded by drainage flow to the river). What can be said is that increased understanding and development of a strong line of communication have removed much of the confrontation from these issues. This, in turn, provides a much more positive environment for the future resolution of these issues.
A further factor that is ensuring ongoing cooperation is an annual report related to water management within the forest2. The report includes a section relating to river operation. This clearly identifies successes and failures and as such keeps pressure on the river operator to continue to consider the needs of the forest in river operations.
Operating procedures for regulated rivers are generally not prescriptive. They exist as guidelines and constraints and the river operator has flexibility to consider various options within these guidelines. As such, there is considerable potential for those involved in managing rivers, and the associated riverine environment, to work with the river operator to achieve widespread small-scale improvements.
This paper has presented examples of where this approach has been highly successful at minimal cost. These examples indicate that the key to achieving improvement is for those involved in river management to develop an understanding of how the river is operated and to build a strong relationship with the river operator. The information provided to the river operator needs to be presented so that it is understandable and applicable. Once this relationship is established, those involved in managing the river and the associated riverine environment can work with the river operator to develop practical, cost effective solutions to real problems.
The opinions expressed in this paper are those of the author and do not necessarily represent those of the Murray-Darling Basin Commission.
1 Hume and Dartmouth Operations Review Panel (1998) Options Paper November 1998
2 Ward K, Leslie D, Rodda G (1997) Water Management in the Barmah-Millewa Forest, Annual
report for 1996/97