Numerical groundwater models are frequently used to inform the groundwater planning process, and can be used to predict potential impacts of different water allocation scenarios or even of individual license applications. However, limited data availability, cost or apparent necessity means that numerical models are not always available to aid in decision-making. In these model deficient areas, a simple, widely used approach employs groundwater extraction limits on a proportion of the estimated recharge. This may not always be appropriate for ensuring sustainability of the resource and ecosystems that depend upon it. The objectives of this review are to provide groundwater managers with an outline of the different approaches available, which are not reliant upon numerical models, and how they can be applied to help protect areas of interest within the environments such as lakes, rivers, and groundwater dependent ecosystems.
A number of different considerations need to be identified to develop a robust, sustainable groundwater management plan. For example, different approaches operate on different time frames such that strategies that work on one time frame might fail completely on other. Therefore, the period over which different groundwater allocations apply can affect the resources/assets and govern the response and possible adaptation within the environment. This review will highlight some key points to aid groundwater managers in selecting appropriate approaches dependent on the identified environmental receptors. Current management strategies (such as buffer zones, groundwater trigger levels, and hybrid approaches) are reviewed to determine their advantage and disadvantages based on their ability to predict changes in groundwater storage, ecosystem protection, and temporal variability in groundwater levels. Furthermore, guidance in the application of alternative, simple, scientifically informed approaches are provided.