River flow is crucial in the life cycle of a suite of estuarine and marine species important in commercial, recreational and Indigenous fisheries in northern Australia, including highly valuable commercial species and iconic recreational and Indigenous target species - banana prawns, barramundi, mudcrabs, threadfins and grunter. Interannual and seasonal cycles of flood- and low-flows sustain both the integrity of species lifecycles and of habitats on which they depend. Iconic species, such as sawfish, and supra-littoral and coastal habitats, such as salt flats, also depend on river flows. These species and habitats have conservation, cultural value and/or economic significance. Water flowing from the northern rivers supports substantial economic and social value, but water is a valuable commodity more broadly, in other sectors. Irrigated agriculture and water development infrastructure also have commitment within substantive government initiatives to develop northern Australia, exemplified by the recent report, “Our North, our future: White paper on developing Northern Australia” (Commonwealth of Australia, 2015).
Various policy outputs by State, Territory and Federal governments, and private industry, comprise a large suite of plans for northern Australia water use. It is difficult to appreciate the extent of these plans, or access detail, as there appears to be no single listing, or collation that summarises features. The current NPF high priority Research Area is “Develop an understanding of ecological and economic tradeoffs of the impact of existing and proposed water resource development in Northern Australia”. As a first step in addressing this priority, this desktop research will collate and review information on the water developments likely to be of interest to northern Australia’s fisheries, principally the Northern Prawn Fishery. Additionally the project will provide the conceptual framework for the future development of ecological modelling to enable multispecies predictions and capture higher order and system level ecological interactions.
Final report
The project reviewed the legislation dealing with Water Resource Management in each of Queensland, the Northern Territory, and Western Australia that effects the management of overland flow in catchments that empty into water managed as part of the Northern Prawn Fishery. The project reviewed the current and future Water Resource Development (WRD) in catchments and landscapes that abut the Northern Prawn Fishery. A web-accessible map portal displays the location and scope of significant projects or infrastructure that incorporate or require WRD for their operation. The project also identified major scientific research projects that provide quantitative information to evaluate the impacts of water development on fisheries and the ecological systems that support coastal productivity.
These initiatives enhance the understanding of NPF industry, management and researchers as to the likely WRD alternatives and consequences across tropical Australian catchments. The project proposed a direction for NPF management and operators to integrate a fishing industry perspective into the water resource planning process via current State/Territory legislation, the most-recent knowledge on impact of river flows on fishery productivity, and engagement in the modification of Water Resource Operational Plans in response to WRD initiatives.
NPF management are encouraged to promote water management and infrastructure design and construction that, as practicable, mimics historical patterns of natural seasonal flow; and only harvest water from high-volume flood flows; to minimize impacts of flow modification on downstream ecosystem services support fishery production. To achieve these outcomes, NPF management need quantitative definitions of flow and flow thresholds that can be stated clearly and withstand scrutiny by water managers and water users.
