Branco River Stage Gradient Determination and Amazon Hydrologic Studies Using GPS Water Level Measurements

Abstract

This study presents the result of a demonstration of Global Positioning System (GPS) hydrologic studies in a remote area. A GPS campaign was conducted using a GPS-equipped vessel and a GPS buoy to measure water level along Rio Branco, a tributary of the Amazon. The GPS water level data agree well with river gauge data and with ENVISAT radar altimeter measurements. The GPS-estimated river stage gradient of Rio Branco is 5.75 ± 0.48 cm/km with 99% confidence, which is higher than previous estimates. This result also agrees well with ENVISAT altimetry results.

Keywords:

• GPS hydrology
• river stage gradient
• satellite altimetry

Acknowledgment

We are grateful to two anonymous reviewers’ comments to this article. We acknowledge Gerald Mader of the U.S. National Geodetic Survey for his kind permission to use his Kinematic and Rapid Static (KARS) software for the computation of GPS water level measurements used in this study. The Taiwanese component of this study is partially supported by the grants of National Science Council of Taiwan (NSC 96-2116-M-194-006 and NSC 97-2116-M-194-007). The U.S. component of this study is supported by the National Geospatial-Intelligence Agency's University Initiative (NURI) program and by the Ohio State University Climate, Water and Carbon Program. The French and Brazilian components of this study are supported by grants from France and Brazilian governments.