Conjunctive water management and Queensland water policy
In Queensland, the Water Act deals with water and for all intents and purposes does not separate surface water from groundwater. The Act also allows for specifying groundwater and baseflow water as one resource.
Consequently, there is only one water resource plan for a catchment that is to include both surface water (overland flow and baseflow water) and groundwater. This plan is a regulation. The operational detail about rules, set back distances etc are set out in a Resource Operations plan. In plans involving baseflow systems, it is the intention for baseflow management rules and groundwater rules to be integrated. For example, where a baseflow discharge ceases at a particular compliance gauge then both surface water pumping and groundwater pumping in the adjacent fractured and alluvial aquifers cease.
In the past, most groundwater models (except for a couple of models to do with artificial recharge) did not include explicit and dynamic consideration of streamflow and at best used the MODFLOW River package to consider streamflow. This is now changing and other packages are beginning to be used to include integrated consideration of stream aquifer interaction.
Water users get one licence with the allocation attached. Some of the conditions might vary between surface water and groundwater to reflect different hydraulics etc. This licence applies only to the taking of a particular volume of water. Conditions for Works to take the water are separate. Works (bores and pumps) are given a development permit that identifies conditions related to those works such as bore construction standards, maximum depths etc.
Legislation is not a constraint to conjunctive water management. The water resource and resource operation plans allow for such integration to take place. The main limitations are the technical tools available and expertise to run the tools, the data availability and the understanding of particular interaction processes. It is unlikely the current MODFLOW package can deliver the level of modelling required; Modflow HMS package is currently being tested on the Pioneer catchment as a first step of improving available tools.
In regard to surface water-groundwater trading: there have been no trades between these sources for aquifer-baseflow systems. It is unlikely that these would be allowed until there is more certainty (reduced business risk) in modelling of the processes and hydrologic data/understanding, and consequently into the modelling of the assessment of the feasibility of the particular trade and the rules for trading in a particular area. In short the approach is caution.
Relevant Links
Department of Natural Resources, Mines and Water (Qld)
Queensland Legislation
References
NGC, 2004. Surface water-groundwater integration and legislative constraints. National Groundwater Committee