How much water do our rivers need?
The Victorian Water Act 1989 gives the development of Sustainable Water Strategies a key role in looking for ways to increase the EWR.(10)
The Northern Region Sustainable Water Strategy (NRSWS) takes a different approach to water recovery, moving away from the scientific FLOWS recommendations and proposing instead ‘an adaptive approach where the environmental flow regime will be improved as much as possible now, at least to a level that will sustain key ecological values, given the consumptive requirements. This adaptive approach will ensure that the EWR reflects current general community consensus on the environmental values to be protected and improved while taking into account the community’s economic and social needs.’ (11) In fact, the draft strategy itself admits that this ‘adaptive approach’ will lead to ‘a continued and rapid deterioration in river health and likely loss of many species at a local and regional level.’ (12)
Figure 1 shows the modeled decline in inflows if the climate experienced since 1996 continues. Actual inflows in 2006/07 were the lowest on record and much less than even this worst case prediction. See Figure 1
(13)
Table 1 shows how total diversions have declined dramatically in line with inflows, but taken together with system losses, they exceeded catchment inflows into the Goulburn, Loddon and Campaspe in 2006/07. Diversions in this year could only be met by using water stored in previous years. With storages at unprecedented low levels, even current reduced levels of use are clearly unsustainable into the future unless northern Victoria returns to wetter conditions. See Table 1 (14)
Table 2 shows the additions to the EWR required to meet environmental flow recommendations as determined by the FLOWS method. In the Loddon and Campaspe, these are higher than actual inflows in 2006/07. See Table 2 (15)
The water recovery targets (additions to the EWR) set in the NRSWS provide only a ‘survival’ regime to protect drought refuges and are not a long term solution. (16) Environment Victoria’s recommendations provide for a healthy instream environment and some overbank flooding to maintain connectivity.
To meet them will require significant changes in the way that catchments are managed and a rebalancing between consumptive and environmental use, and a longer term commitment by governments to tackle the drivers of climate change and reduce greenhouse gas emissions.
References
(10) Water Act (1989) Section 22C
(11) Northern Region Sustainable Water Strategy Background Report 8 ‘Identifying water recovery targets for the environment’. DSE, 2008
(12) Northern Region Sustainable Water Strategy, DSE 2009, p 131
(13) Data from NRSWS and State Water Accounts 2006/07
(14) All figures from draft NRSWS except actual figures for 2006/07 from Victorian Water Accounts 2006-2007
(15) The Ovens has a low level of use but is a very significant contributor to flows in the Murray and to South Australian water supply
(16) NRSWS p 131
