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• Nationwide streamflow projections for Australia informed by CMIP5 and CMIP6. • Vast majority of CMIP5 and CMIP6 GCMs project less winter rainfall across Australia. • Lower winter rainfall translates to a significant reduction in annual runoff. • Modelled median projection of runoff shows a 50% reduction in far southwest Australia. • Modelled median projection of runoff shows a 20% reduction in far southeast Australia. Projections of streamflow under future climate are essential for developing adaptation strategies in the water and related sectors. This paper presents nationwide streamflow projections for Australia informed by climate change signals in CMIP6 GCMs and compares the projections with those from CMIP5 GCMs. The modelled future runoff projections driven by CMIP5 and CMIP6 GCMs are relatively similar for far southern Australia. The median projection is a 50% reduction in mean annual runoff in far southwest Australia and 20% reduction in far southeast Australia by 2046–2075 relative to 1976–2015 under the high SSP5-8.5/RCP8.5 global warming scenario. The vast majority of CMIP5 and CMIP6 GCMs project less winter rainfall across Australia. As most of the runoff in far southern Australia occurs in winter and spring, the lower winter rainfall translates to a significant reduction in annual runoff. It is therefore prudent to plan and manage for a reduction in future water resources, particularly in the densely populated and important agricultural regions in southeast Australia. There is less agreement between GCMs in the summer rainfall projection, with the CMIP6 GCMs generally projecting a wetter future (or smaller decrease in rainfall) than the CMIP5 GCMs. The modelled median projection for mean annual runoff is a 10% reduction in the south-east coast, 5% reduction in the north-east coast and little change in northern Australia. More GCMs project an increase rather than a decrease in the interannual variability of rainfall, and this would further amplify multi-year hydrological droughts. [ABSTRACT FROM AUTHOR]

• Grassroot collective action can lead to successful groundwater co-management. • The interaction between impacting factors and collective action is dynamic. • Human and social capitals are key to successful collective action. • Collective action needs a 2-way interaction between formal and informal institutions. Resource-user participation in decision-making, through local collective action, likely contributes to effective groundwater management and protection. Despite efforts to construct generalized theoretical frameworks explaining factors influencing successful collective action in groundwater management, this is a highly complex process that remains challenging. This paper analyzes factors facilitating and impeding collective action in groundwater management, using the rare and successful collective-action example of the Angas Bremer irrigation district (South Australia). Drawing on data gathered through semi-structured interviews this paper further explores the context under which collective action arose and changed over time. The findings show a dynamic transient interaction between the following factors responsible for the rise and fall of collective action: (i) perceived crisis, (ii) small, homogenous community (iii) strong leadership from respected community members, (iv) shared norms and values, (v) shared goals, and (vi) trustworthy two-way relationship between resource users and formal institution. Although it is difficult to generalize from one case study, collective action and groundwater management are highly contextual. These findings are useful (i) for other communities with similar characteristics, (ii) to explore conditions for achieving successful groundwater governance including efficient and effective reforms, (iii) to highlight the importance of participatory management processes, (iv) to help government agencies understand what motivates communities to engage in collective action and how that leads to successful groundwater co-management, and (v) to expand on a very small body of literature documenting stakeholders narratives on collective action and groundwater management. [ABSTRACT FROM AUTHOR]

• An innovative framework to derive intensity-frequency-duration curves from satellite data for remote areas. • A variant of the Bartlett-Lewis model calibrated with sub-daily satellite precipitation data to disaggregate daily gauge data. • This new framework was tested for a wide range of climates in Australia. • IFD curves can be derived with reasonable accuracy for data scarce regions. Intensity-frequency-duration (IFD) curves (also known as intensity-duration-frequency (IDF) curves in some regions) are widely used to take into consideration the probability of occurrence of extreme precipitation for the design of water related infrastructure. Derivation of IFD curves is based on statistical analysis of observed extreme precipitation events and thus the reliability of the curves mostly depends on the record length of observations. At sub-hourly timescales however, ground-based precipitation observations are often absent or very limited in terms of spatial coverage and record length, particularly in remote areas around the world. Given the availability of satellite-derived precipitation products (SPPs) with finer spatiotemporal resolution and near-global coverage, there is great potential to use these products in the planning and design of infrastructure. This paper proposes a novel framework, SIFD (Satellite-derived IFD curves) to combine long-term daily gauge data and sub-hourly SPP to estimate IFD curves for time intervals from 0.5 to 24 h. A recent variant of the Random Parameter Bartlett-Lewis Rectangular Pulse model (RPBLRPX) was used to disaggregate daily gauge data to derive IFD curves. In the absence of sub-daily rain gauge data, the statistics required for the RPBLRPX model were obtained using the Integrated Multi-satellitE Retrievals for GPM (IMERG; 30-min, 0.1° resolution) product derived from the Global Precipitation Measurement (GPM) mission. Performance of the SIFD framework was tested against gauge data from seven Australian sites across a wide range of climatologies. The disaggregation scheme coupled with the RPBLRPX model was capable of reproducing the wet-period mean intensity, wet-period standard deviation, and wet-period fraction with reasonable accuracy across the sub-daily timescales. The coefficient of determination ( r 2) values were 0.39 (mean intensity), 0.38 (standard deviation), and 0.87 (wet-period fraction) at 0.5 h timescale. Furthermore, despite some differences in methodology and record length, the IFD estimates computed using the SIFD framework were fairly close to those of the Bureau of Meteorology (BoM). The skill metrics for Sydney were the best with a bias ratio (BR) of 1.01, root mean square error (RMSE) of 13% of the mean of the BoM estimates, and a Nash-Sutcliffe coefficient of efficiency (NSE) of 0.97. The worst case was found at Hobart (BR = 1.43, RMSE = 66%, and NSE = 0.26). Overall, the results indicate that the proposed SIFD framework could provide a viable alternative to estimate unbiased IFD curves at the sub-hourly timescale in the absence of adequate sub-hourly ground-based observations. [ABSTRACT FROM AUTHOR]