This award will explore interactions among variables that influence the development of a river's longitudinal profile. The Principal Investigator will use the natural experiment provided by the widespread glacially induced uplift in Sweden, which contains a series of rivers with similar characteristics but slightly different base level histories. The PI will test a series of five hypotheses that focus on the influence of drainage area and discharge (H1), substrate properties (H2, H3), and uplift rate (H4) on river longitudinal profile and channel geometry, and on the adequacy of a stream power law to describe river incision where knickpoints in the form of rapids (rather than waterfalls) are present (H5). A second objective is to estimate relative erosion rates at selected sites along each river using thresholds for clast motion and bedrock incision combined with the frequency of flows exceeding these thresholds. The research outlined in this proposal will allow the PI to test the applicability of the stream power law along rivers with knickpoints in the form of steep rapids, and the inference of previous investigators that response to uplift scales with drainage area.
Broader Impacts. The proposed research will provide field experience for graduate and undergraduate students. The research will also foster collaboration with Swedish riparian ecologists, and increase understanding of the history and mechanics of river adjustment following deglaciation, which are known to influence riparian community structure and diversity.
