VHF radar measurements of flow in a salt marsh creek

Abstract

A VHF ocean radar system was deployed for one month in a salt marsh in coastal Georgia, USA. In this environment, radar backscatter from the marsh grass is highly attenuated and scatter from water in the narrow creeks has a broad band of Doppler shift due to the horizontal variation in water speed across the channel. By assuming a monotonic velocity profile from the edge to the middle of the channel, a theoretical relationship is derived to link the broadening of Bragg energy in the echo spectrum to varying water speed. A methodology is developed to derive the cross-creek profile of velocity variation in the main channel of the salt marsh.