Monitoring is critical for effective groundwater management, especially in systems with competing groundwater interests, such as the Great Artesian Basin's (GAB) Surat Basin (~180,000 km 2) in Queensland, Australia. Coal seam gas (CSG) activities in the region have led to public concerns about potential impacts on groundwater and to landholder complaints about impacts on boreholes. To deal with these issues, the Queensland Government established the Groundwater Net and Groundwater Online citizen-science monitoring programs, which started in 2013 and were fully operational by 2018. Groundwater Net is a community-based education and groundwater monitoring program in which over 500 landholders across 16 local groups have attended workshops and provided over 1,000 groundwater-level/pressure readings from their boreholes using the My Groundwater Monitoring website. Annual workshops provide a forum to share and discuss monitoring results and knowledge. Regularly updated status reports compare monitoring data from CSG companies and the government with landholder data. Groundwater Online is a complimentary program using continuous-monitoring loggers and telemetry on 46 private boreholes. Citizen science now provides 13% of GAB monitoring boreholes in the CSG area. By effectively engaging with borehole owners, and empowering them to monitor, many opportunities arise for better groundwater management. Consequently, the spatial reach of groundwater monitoring and its frequency have increased, landholders are educated about groundwater systems, and borehole owners generally feel more confident about monitoring conducted by CSG companies and government.

Hong Kong lies on the SE margin of the Cathaysia Block and straddles the NE-trending Lianhuashan Fault Zone, one of the dominant structural features of SE China. Isotope signatures of the Mesozoic granites have indicated that the zone overlies a major crustal discontinuity. The proposed gravity model of Hong Kong consists of a heterogeneous upper crust underlain by middle to lower crust composed of a felsic Archaean segment, approximately 25 km wide, flanked by more mafic Proterozoic crust. The southern boundary of the felsic segment dips steeply to the north, whereas the northern boundary is subvertical. Euler gravity anomalies define the fundamental faults in the upper crust, and many of these can be correlated with faults that have been mapped at surface. The middle to lower crustal discontinuities are considered to be associated with a major shear zone within the Cathaysia Block that has similar dimensions to transcratonic structures in other Precambrian shield areas. The geological development of Hong Kong and neighbouring SE China has largely been controlled by periodic reactivation of this deep crustal shear zone since the late Neoproterozoic.

Resistivity methods are widely used as an aid to siting water-supply boreholes in basement terrain. Adverse conditions due to shallow bedrock can be identified readily but specific targets such as narrow conductive zones may be missed; quantitative interpretation may be less reliable than is often assumed. Electromagnetic (EM) profiling will detect localized zones of deeper weathering and the effects of fracturing at shallow depths, and it is used for the precise location of anomalous ground indicated by lineations on aerial photography. Routine EM surveys give better lateral resolution than resistivity for the conductive targets of interest. The 2-D and 3-D EM modelling techniques needed for interpreting the conductor geometry realistically are still under development. Geophysical methods must be applied with due regard for the targets being sought and the local geological setting: they will not always be appropriate and resources should be targeted on districts where problems can be solved. Qualitative interpretations are adequate in some situations but more rigorous field procedures and analytical techniques are needed to ensure that useful hydrogeological information is obtained.

Regional gravity and aeromagnetic data of Wales have been processed using a variety of techniques. Image processing has greatly assisted qualitative interpretation, whilst automated procedures have provided additional quantitative information. The shaded relief images emphasize gradients in the potential fields, and are useful for displaying strong linear features. The Euler deconvolution method produces plotted solution maps, which define the position of the source of the gravity and magnetic anomalies. Euler solution maps of Wales and the adjacent continental shelf are presented for the first time. These maps are interpreted in relation to the known geology, with special emphasis on the Lower Palaeozoic Welsh Basin. It is proposed that the Euler solutions define a network of fault-bounded blocks within the Precambrian basement.