ITC and WatER: The Proposed Water Elevation Recovery satellite mission
Remco Dost(1) , Ben Maathuis(1) , and Bob Su(1)
P.O. Box 6,
7500 AA Enschede,
The water cycle and its associated hydrological processes are, as known and experienced by a majority of society, of a very dynamic nature both in space and time.
The core activities of the Water Resources (WRS) Department of ITC can be phrased as “develop and transfer knowledge in geo-information science and Earth Observation for water resources management and hydrology”, thereby combining water cycle science and water resource analysis and management with unbiased data acquisition from space and geo information technologies.
To this end, the WRS Department is engaged in scientific activities that require the Remote Sensing of surface hydrological processes and the WatER mission can compliment these activities by providing global centimetric accurate measurements of water surfaces at a high spatial and temporal scale.
For example, to determine flood effects on a regional scale at the confluence of the Megha and the Ganges rivers in Bangladesh, sequential multi-spectral satellite images and a band rationing technique to separate water and land was used. This approach reveals the spatial distribution of the inundated areas (flood stage mapping) and river dynamics (floodplain and channel alterations). When combined with measurements from a georeferenced active sounder, the changes of the river bottom can be mapped. Using water level measurements, flood volumes can be determined and predictions on possible future flooding can be made. The water levels are nowadays mostly recorded using staff gauges or (automatic) water level recorders and are of limited spatial coverage. The WatER mission could improve on flood predictions and flood damage assessments because it will help us better understand flood dynamics spatially and temporally.
WatER can also improve on hydrological and environmental studies. The WRS Department has been carrying out M.Sc. fieldwork in the Lake Naivasha area in Kenya for almost 10 years. Here, the water balance of the Lake Naivasha basin is highly dynamic and natural fluctuations of the lake level during the last century have been as much as 8 meters. The lake level was used to calibrate hydrological models of the catchment by comparing simulated and measured lake levels. Once calibrated, future lake levels can be forecast using change scenarios that evaluate changes in e.g. population or climate, and lake management can be improved.
The intensive collaboration of ITC with the Institute of Tibetan Plateau Research of the Chinese Academy of Sciences has established the long-term monitoring of the water cycle and climate processes on the Tibetan Plateau, in particular the surface waters, e.g. the levels of the Namqu Lake as influenced by increased global warming. Having access to global lake water levels as provided by WatER makes it possible to not only study ungauged lakes, but also the dynamics between (gauged) lakes.
The expertise and global network that ITC obtained in its 55 years of existence, can also contribute to the WatER mission. Providing access to its network for mission validation purposes and sharing expertise on the use of Earth Observation technologies and GIS science for problem-solving water resources issues with users of the WatER mission data are a few examples.