Å·ÃÀ¿Ú±¬ÊÓƵ

Hannon, Mark T ¹ ; Kettner, Albert J. ² ; Syvitski, James P.M. ³ ; Overeem, Irina ⁴

¹ CSDMS, INSTAAR
² CSDMS, INSTAAR
³ CSDMS, INSTAAR
⁴ CSDMS, INSTAAR

Zones of erosion and deposition, and knowing how to locate them, are of interest to geoscientists, hydrologists, and petrologists. River longitudinal profiles can reveal areas of bedload erosion and deposition. Utilizing the worldwide SRTM 3 arc-second DEM satellite derived data elevation vs. distance is mapped and plotted. The SRTM DEM provides the ability to identify general large-scale patterns (slope, slope change, sinuosity) along a river’s course. This analysis joins auxiliary data sets to develop an understanding of the external and internal influences that are pressed upon and inherent within the lower 100 meters of the river systems. Changes in the slopes of three rivers were examined for external controls by overlaying geological data of rock type and fault locations. Neotectonics appears to impact the slope and/or sinuosity of the Mississippi, Niger, and Magdalena rivers. Results indicate that sinuosity is influenced by the growth faulting found in the mud dominated systems of the Mississippi and Niger. The resulting sinuosity is greatest in these rivers where the growth faulting is occurring. The Magdalena has several regions where a strike-slip fault crosses the river, resulting in increased slopes with the more parallel the encounter. Additionally, stretches of each river were broken into different segment lengths based on meander wavelengths to compare sinuosity with the river’s slope. Contradictory to previous findings, the sixteen rivers studied here show that slope and sinuosity are not strongly correlated at the reach scale. The total river's longitudinal profile of the lower 100m, provides an average slope and sinuosity throughout the entire system and increases the correlation between slope and sinuosity.