The Lower Murrumbidgee Valley is the major aquifer in the MDB, which occupies 31 372 km2. It contains a number of regional aquifer systems consisting, mostly, of semi-consolidated to unconsolidated sedimentary deposits that have a maximum thickness, in the east, of about 170 metres and about 400 metres at the western extent. The SDL for the Lower Murrumbidgee was determined using a numerical model. Using model results as a guide, negotiations were carried out with Groundwater users to agree on SDL of the Lower Murrumbidgee. Similar study was done for the Lower Murray Aquifer to determine its SDL.,Groundwater sharing plans of nine major aquifers on NSW are in place since 2006, and are being revised at present. To assess the performance of the Groundwater Sharing Plans, this study was conducted. It involved (1) Identification of key observation bores in each aquifer, (2) removal of seasonal influences on groundwater levels, (3) removal of spatial variations, (4) and a statistical test of whether changes to groundwater levels since implementation of the Plans were significant.,Managed Aquifer Recharge (MAR) interventions are widely adopted across India. While the literature on MAR in India is vast, tthere is an absence of a structured approach to evaluate the performance and impact of MAR interventions. Often, performance and impacts of MAR have been commented upon together, without distinguishing the two. We proposed that performance and impact are different from each other, and that the evaluation of MAR interventions should take into account such differences between them. A framework for performance and impact analysis, based on three levels, viz. primary, secondary and tertiary, was outlined.,With the launch of the Gravity Recovery and Climate Experiment (GRACE) mission, it is now possible to obtain data at broad spatial scales to examine past trends in changes to groundwater resources. In this study, the GRACE data were used to estimate changes to monthly total water storage (TWS) and groundwater storage in different agro-climatic zones of Rajasthan, India. The methodology based on GRACE data was found to be useful in detecting large scale trends in groundwater storage changes covering different agro-climatic zones, especially in regions where historic records of groundwater levels do not exist.,River Ganga flows a course of more than 2,500 km through north and eastern India, Nepal, and Bangladesh. Approximately 10% of the irrigation command area (8,268.6 km2) is waterlogged following monsoon. Surface drainage is constrained by undulating topography, and drainage due to percolation is constrained by thick clay layer below the root-zone. In this project, vertical drain (VD), a new concept, is employed to minimize the duration of seasonal waterlogging and tested in Mukundpur, Vaishalli District, Bihar, India. This is superior to horizontal drains, which relocates fertile top soil during levelling, and require maintenance and disposal sites for drainage.,In arid regions around the world, recharge dams have been built across wadis to detain runoff and recharge groundwater. Almost exclusively, all wadis carry a considerable amount of silt and clay during runoff events. These sediments settle upstream of the dam during detention, reducing the rate of infiltration. As a consequence recharge potential upstream of the dam is significantly reduced. Unfortunately, desiltation can occur only after the dam has dried due to infiltration, downstream release and evaporation. In this project we proposed DARE, Drain Accelerated Recharge which bypasses the silted layer and maintain high rates of recharge during inundation.,The Ganges River Basin (GRB) has abundant water resources, but the seasonal monsoon causes a mismatch in water supply and demand. We assessed the potential of the Ganges Water Machine (GWM) to meet the increasing water demand and mitigate the impacts of floods and droughts. The realizable potential is high in seven sub-basins, , is moderate to low in 11 sub-basins, there is little or no potential in four sub-basins in the western part. A preliminary ex-ante cost-benefit analysis shows that the GWM is a financially viable intervention with a benefit to cost ratio of over 2.3.,In NSW Mallee, better economic returns may be obtained if land is cleared for wheat or grazing. However, it is necessary to identify areas where the environmental impact is minimal before clearing is allowed. To facilitate this determination, a hydro-economic modelling approach, which identify areas suitable for clearing, maximise profits, but will not have a detrimental effect for at least 200 years.,During late 1980s, in irrigation areas of SE Australia, recharge from rice cultivation was contributing to waterlogging and salinization. A hierarchical multi-disciplinary multi-criteria framework was developed to determine the scope for crop diversification to maximise profits while minimising waterlogging.