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The use of Earth observation technology such as satellites, unmanned aircraft, or drones as part of early-warning systems and disaster risk reduction plans is a widely researched and established area of study. However, the use this technology can have in the provision of water, sanitation and hygiene services in the response and recovery phases of a disaster is not widely researched. A systematic literature review was undertaken assessing relevant literature to identify Earth observation technology and methods that can be applied to the context of water, sanitation and hygiene in disaster response and recovery. Whilst there were many water-related studies, there was a lack of studies looking at the potential uses of Earth observation for sanitation. This is an area that requires further research. Three main common uses of Earth observation technology were identified as relevant: (1) Monitoring of surface water quality; (2) Groundwater Sensing; and (3) Mapping and monitoring of hazards and infrastructure. Whilst the studies of Earth observation in these areas highlight that this technology could be usefully applied to assist with water, sanitation and hygiene during disaster response and recovery, more research is needed and there are limitations to consider—predominantly that funding, communication and integration between many agencies and technologies are required. Additionally, some technologies are subject to local regulations which can cause restrictions to their use over contested or private areas, or trans-national boundaries—common situations in disasters. This review was largely influenced by the search strings inputted during the identification of relevant literature; changing the search strings would likely result in a different combination of literature available for review and subsequent variations in the findings.

Today, inhabitants residing in floodplains face a serious and perpetual threat of flooding. Flooding causes fatalities and considerable property damage in metropolitan areas. Therefore, robust structural measures need to be adopted to eliminate flood catastrophe. Structural measures in the floodplain are the most promising solutions. However, there are cost-associated factors for proposing a flood retention plan. Navsari city (98.36 km2, area extent) of Gujarat was used as a case study to investigate the impact of mesh grid structures (100 m, 90 m, and 50 m) along with structural measures for the preparation of a flood retention plan. The HEC-RAS 2D hydrodynamic model was performed for the Purna River. The output of the model was characterized by four different scenarios: (i) Without weir and levees (WOWL), (ii) With weir (WW), (iii) With levees (WL), and (iv) With weir and levees (WWL). The statistical parameters (R2, RMSE, NSE, inundation time, and inundation area) were determined to evaluate model accuracy. The outcome of the model revealed that a 50 m size mesh grid exhibited more accurate results, yielding high NSE and R2 values (0.982 and 0.9855), a low RMSE value (0.450 m), and a smaller inundation area (114.61 km2). The results further revealed that the WW scenario was the most effective flood retention measure as it delayed the flood water for up to 16 h, and managed the flood with the WOWL case. Moreover, the mean error (WW scenario) estimated from profiles 1 and 2 ranged from (−0.7 to 0.62) and from (−0.1 to 0.02 m), respectively, which were evaluated as very low when compared with other scenarios. The novel scenario-based flood retention plan emphasizing the stability of mesh grid structures using the hydrodynamic model can be applied to any other region around the globe to recommend efficacious structural flood measures for flood decision making systems.