Monitoring small water bodies (<50 ha) is difficult due to their size, limiting accurate assessments of surface water (SW) resources required for agricultural production and watershed hydrology. In ...environments where livelihoods depend on surface-water storage (SWS) structures, satellite altimetry-derived water levels are often unavailable. Therefore, seasonal reservoirs require a robust and cost-effective approach for estimating SWS. To approximate SWS throughout a typical environmental setting where irrigation reservoirs are found, we investigate the utility of TanDEM-X digital elevation model (DEM) to extract bathymetry of seasonal reservoir structures. Empirically-derived SWS relationships are combined with estimates of SW area from radar and multi-source optical satellites to illustrate the potential for rapid SWS estimation using satellite-based SW extent as input. Two application examples illustrate the approach: (i) estimating the maximum volume of water in a southern Indian river basin for two monsoon seasons; and (ii) a time-series analysis using a high-volume of satellite observations to show the cycle of water (inflow and outflow) at the reservoir scale. SWS volumes at water levels below 1.5 m were estimated within an absolute volume error range of 6–8%. This study illustrates the applicability and challenges of using satellite remote sensing observations to continuously monitor reservoir SWS. Despite the cloud independent capability for operational monitoring of SW area, Sentinel-1 data should be combined with frequent and high spatial resolution CubeSat observations for hydrometric monitoring of reservoirs to reduce observation errors. Furthermore, we highlight the multi-sensor approach (optical and radar) to achieve high spatio-temporal resolution monitoring of small reservoirs over large spatial scales.
Climate change, increasing population and changes in land use are all rapidly driving the need to be able to better understand surface water dynamics. The targets set by the United Nations under ...Sustainable Development Goal 6 in relation to freshwater ecosystems also make accurate surface water monitoring increasingly vital. However, the last decades have seen a steady decline in in situ hydrological monitoring and the availability of the growing volume of environmental data from free and open satellite systems is increasingly being recognized as an essential tool for largescale monitoring of water resources. The scientific literature holds many promising studies on satellite-based surface-water mapping, but a systematic evaluation has been lacking. Therefore, a round robin exercise was organized to conduct an intercomparison of 14 different satellite-based approaches for monitoring inland surface dynamics with Sentinel-1, Sentinel-2, and Landsat 8 imagery. The objective was to achieve a better understanding of the pros and cons of different sensors and models for surface water detection and monitoring. Results indicate that, while using a single sensor approach (applying either optical or radar satellite data) can provide comprehensive results for very specific localities, a dual sensor approach (combining data from both optical and radar satellites) is the most effective way to undertake largescale national and regional surface water mapping across bioclimatic gradients.
I would say if you're passionate about what you are studying and if you've found something that motivates you to wake up and go to class or go to the office every day, then stick with it. You are not ...alone. There are many initiatives that are waiting to support you. And find a woman that inspires you.
Forecasted population growth and a changing climate will intensify the challenge of securing water for agriculture. While rainwater harvesting (RWH) reservoirs constitute a promising alternative and ...complimentary source to groundwater withdrawal for irrigation and have supported small-holder agriculture across South India for millennia, their hydrological role remains not well understood. Synonymous to how Earth Observation (EO) gravitational studies have opened the public and scientific discourse on groundwater sustainability, new EO developments further our understanding of RWH reservoir hydrology and their role to further future sustainable groundwater management. Using a reservoir-dominated region in South India as an illustrative case, three areas are discussed where remote sensing will accelerate our understanding of water resources sustainability for agriculture in the rural farming landscape of South India. These include: 1) advances in temporal and spatial remote sensing; ii) a perception shift, where data-driven remote sensing can support or compliment physical process understanding; and iii) the critical need for increased communication to understand end-user needs.
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