Flooding hydraulics are well modeled but poorly measured by current methods. Floodplain water levels, for example, are rarely measured during the passage of a flood wave. Instead "wrack marks" are measured after the event has occurred, and the marks, which indicate some water level during the flood, are often considered to be the high water mark. Any dynamics (rising and falling of water) during the flood event are lost. SWOT aims to provide water level records for any flooding events that underlay a given satellite overpass. SWOT scientists will also be able to look at synergistic combinations of SWOT and other satellite datasets, modeling, and in situ observations to improve capabilities.
Model predictions (and hence drought monitoring) can be greatly enhanced through assimilation of space-based surface water observations such as those from the future AirSWOT and SWOT missions. There may be opportunities to combine surface water measurements from AirSWOT and SWOT with other satellite data and modeling (i.e., GRACE) to improve observations and predictive capabilities.
Reservoir storage is poorly known and there is a lack of pervasive measurements documenting the water levels. Changes in reservoir storage may be known to governing agencies, but can be unknown to downstream neighboring communities and countries, making it impossible for communities downstream to adequately model future flow dynamics within their borders. SWOT is designed to accurately measure monthly to seasonal changes in reservoir storage. The information will be made available to water managers and other interested parties.
This topic is related to reservoir storage, but has additional important considerations. For example, the flow of water in some rivers may be governed by agreements between countries. However, monitoring this flow can be problematic for both technical and economic reasons. SWOT may help to overcome these potential roadblocks by uniformly measuring water surface elevations across national boundaries, globally, and on a regular basis by delivering global coverage approximately every 11 days.
River operators often need to know what water levels and expected flows are. With this information, boats and ships can modify onboard bathymetry data to know actual water depths. SWOT is designed to provide the first-ever measurement of along stream water surface elevations. Reliance on gauges is the current standard in river operations, but SWOT data would enable significant enhancement to these point-based gauge measurements by mapping water levels along any given stretch of river.
Floods result in tens of billions of dollars in property damage and business interruption globally each year. In Thailand alone, floods in 2011 resulted in an estimated billion in economic loss, according to the World Bank. However, when flood hazards are known and adequate mitigation measures are implemented, flood losses can be reduced significantly. A recent study reported on in Engineering News Record found that sites throughout the U.S. that invested in simple flood preparations experienced 70% less property damage when flooding occurred. Achieving such benefits requires full understanding and characterizations of flood exposure. SWOT would provide critical information to help businesses assess flood risk and better prepare for protecting assets. Risk assessment methodologies used by property insurance companies increasingly will rely on accurate characterization of site conditions, including flood hazards, which can be provided by regional remotely sensed data.
Marine operators such as marine transporters, commercial fishing vessels, oil companies with offshore production facilities, and recreational boaters, to name a few, will be able to use data from SWOT. The high-resolution information about ocean circulation and the finer scale resolution (estimated to be between 10 and 200 km over the ocean) can be highly beneficial to optimizing their operations in both coastal and open ocean environments.
Coastal Zone Management
With its higher-resolution data products, AirSWOT and SWOT will have the potential to provide key inputs for supporting real-time operational applications in the coastal zone. Within a few tens of kilometers from the coast, the new mapping capabilities provided by the future SWOT instruments, will improve knowledge of coastal tides, as well as smaller-scale circulations features that impact the coastal zone. Specific applications in this area may include storm surge modeling, sediment transport, water quality issues, high-resolution nearshore circulation modeling, and others. Related links: COASTALT
Better understanding of the finer-scale movement of energy in the ocean, and of the vertical transport of carbon and heat is crucial for understanding the role of the ocean in regulating climate change. Accurate knowledge of large-scale circulation is also required. Higher SWOT measurement accuracy from sub-mesoscale (less than 200 km) to global scale will support critical climate studies as we navigate into a future of a warmer world.
Fisheries operations can benefit from long-term, regional observations of ocean conditions such as may be provided from remotely sensed data by observing and measuring physical properties of the ocean that influence fish habitats and migration. Altimetry data products, particularly the higher-resolution SWOT data, can be combined with other sensor data (ocean color, wind measurements, ocean temperature, salinity) to provide critical information for support of good fisheries management practices, optimizing operations (bathymetry, weather), safety at sea and more.