Spatial Gauging on Canterbury Plains Using RADARSAT
A river's discharge is traditionally monitored by measuring its water depth or surface elevation, and then converting these measurements to water discharge using a calibration or stage-discharge rating curve. The possibility of monitoring changes in river flow rate from satellites has been largely ignored hitherto because of the difficulty of making sufficiently precise measurements of the water surface elevation. Kuittinen (1992, Appendix 1B) assessed the capability of remotely sensing surface water river stage as "No evidence of feasibility", but, as reviewed more recently by Smith (1997), rapid developments in the application of microwave technology have changed that situation. The research described here uses a different approach. Instead of using the traditional measurements in the vertical plane as a surrogate for discharge it uses the approach of Smith et al (1995), exploiting the expansion of water surface area with increasing discharge to obtain a calibration curve relating "effective width" to discharge.
Spatial Gauging on Canterbury Plains Using RADARSAT