Management of environmental water – efficient and effective
The establishment of the Environmental Water Reserve (EWR) in 2005 brought in a requirement that its management should ‘aim to achieve the most effective use of environmental water, achieving the greatest level of environmental benefits possible and minimizing as far as possible any adverse impacts on water users.’ (20)
This requirement has become entrenched in government thinking and is developed in the NRSWS. It now includes integrated management across the northern region, complementary works to protect habitat and improve water quality, structural works including pumps and regulators; and the use of consumptive water en route. (21) These are all crucial aspects of water management and can greatly enhance the effectiveness of the EWR, but they are not substitutes for increasing the volume of the EWR.
Most of the EWR for northern Victoria cannot be actively managed. It is water that is left over once consumptive demand has been satisfied. Only 6% (232GL) is held as clearly defined environmental entitlements, and of this only 29.6GL is high reliability entitlement with a chance of being actually allocated in future. (22) That is for all the rivers and wetlands in northern Victoria! Thus the scope of environmental managers to use the EWR to achieve environmental objectives beyond emergency watering is severely limited by lack of adequate entitlement. This situation will be improved slightly with the creation of an environmental water entitlement for the Goulburn from NVIRP savings and the portfolio of entitlements being built up by the Commonwealth Environmental Water Holder. However, water recovery targets set through the NRSWS and adopted by the Commonwealth must be high enough to support more than just protection of drought refuges.
In the light of the inadequacies of the EWR to meet its objectives, effective use of the available environmental water becomes crucially important. Investment in complementary works, particularly the management of the riparian zone, is essential. The renewal of Crown Water Frontage licenses in October 2009 was a missed opportunity to improve management of publicly owned land along rivers. These frontages, which make up about 30,000km of stream length, are public land leased to adjoining land holders who are responsible for their upkeep. Replacing grazing licences with conservation licenses, as envisaged by the Victoria National Parks Association, would significantly improve their management and condition. (23)
Structural works are another key element in effective use of environmental water. The Living Murray program has pioneered the use of pumps and regulators in the delivery of water to its icon sites, and the use of irrigation channels and pumps has been crucial in the effective delivery of Murray Flora and Fauna Entitlement water to wetlands. The continuing survival of the Murray Hardyhead in the wild in Victoria depends on them. However significant further investment is required to make best use of Living Murray and other environmental water. For example, the investment of $43 million in works at Lindsay Island would reduce the amount of water needed from around 1200 GL/month to only 90GL to flood around 5,000ha (24). Similar benefits can be achieved at Gunbower, where almost 5,000ha of wetlands and red gums can be flooded using only 165GL/month with works instead of at least 1,000GL per month without. The strategic purchase of floodplain property to allow the passage of water, for example on the lower Goulburn, could be an alternative or enhancement to investment in structural works. However, structural works will never entirely recreate the benefits of natural floods as they do not bring all the benefits of floodplain connectivity.
Policy settings can have a significant impact on the effectiveness of environmental water entitlements. A key policy decision concerns carryover. To recreate a flood regime, the environment requires water in large but infrequent amounts, as opposed to irrigators for whom a reliable annual supply is vitally important. The ability to accumulate environmental water allocations over a number of years, as currently happens with the Barmah entitlement, is really important for environmental managers. The proposal brought forward through the NRSWS process for a new type of carryover called the ‘spillable water account’ that can be accumulated for a number of years (25) is a big step forward in meeting the environment’s need.
One final area where the effectiveness of the EWR can be increased is through active cooperation between environmental managers and water corporations. This can include use of consumptive water ‘en route’ to provide environmental benefits, such as routing water from Lake Eildon for delivery to Mildura through the Waranga Channel and the lower Campaspe to provide much needed flows, rather than through the lower Goulburn which may suffer from excessive summer flows. Other opportunities for maximising environmental benefits depend on the location where environmental entitlements are stored. In multi-storage systems, the location from which environmental water is released can have a significant impact on the distance the water has to travel to meet the desired objective. Decisions by the water corporation can increase transition losses and thus reduce the quantity of water available to achieve the environmental objectives.
References
(20) OWOF p62
(21) NRSWS p137
(22) NRSWS Appendix 4 p187
(23) http://www.vnpa.org.au/subsection.php?subsection_id=113 accessed 24/08/09
(24) DSE Office of Water submission to MDBA Issues Paper on Sustainable Diversion Limits. Jan 2010
(25) DSE (2009) A proposal for future carryover arrangements http://www.ourwater.vic.gov.au/__data/assets/pdf_file/0004/49792/Proposal-for-future-carryover-arrangements.pdf viewed 24/8/09
