Application of a water balance model using depth measurements in the Mungalla wetland in north Queensland, Australia

• Simple wetland water balance model only requiring daily weather and depth data. • Application of the model to 10 years of data in a wetland in Queensland, Australia. • Demonstration of the highly variable water balance within and between years. • Potential model applications to estimate ecological risks and pollution removal. The flows of water into and out of wetlands are primary determinants of their ecological condition, habitat suitability and potential for removing pollutants. However, comprehensive measurements of the complete water balance are rarely made due to monitoring complexities and associated costs. The water balance model described here has the advantage that it can provide an estimate of the main inflows and outflows to and from a wetland without the need for their direct measurement. The only daily variables required are weather data and the wetland depth, which is easy and inexpensive to measure with simple loggers. The model is applied in the Mungalla wetland, north Queensland, Australia using a unique 10 years of daily depth measurements. Modelled inflows and outflows are shown to be highly variable within and between years, according to the rainfall inputs. This illustrates the highly dynamic nature of these wetlands which has implications for their ecological condition. The model has also been applied in two other wetlands in Queensland ( Wallace and Waltham, 2021 , Wallace et al., 2022 ), demonstrating its potential application in many more wetlands. We also discuss the potential use of the model to determine aquatic risk periods and the estimation the nitrogen and sediment removal of different wetlands. This approach will be very valuable in helping evaluate the type and location of treatment wetlands on coastal floodplains that can make the best contribution to load reductions to the Great Barrier Reef lagoon.