In classical considerations of river morphodynamics, sediment in transport that is finer than 62 microns (i.e. in the silt and clay sizes) has been ignored.  In sand-bed streams, it has been assumed that only the sand part of the load interacts with the river.  Yet sand-bed rivers usually have floodplains that are rich in mud.  The channels and floodplains of sand-bed rivers co-evolve, and this co-evolution cannot be modeled without an understanding of the process by which floodplains capture and lose sediment in both the sand and mud size ranges.  The research effort consists of three elements.  The first element is a field quantification of the role of bank erosion in exchanging sediment between the bed and floodplain of a meandering river.  The analysis reveals that most (~ 90%) of the sediment mined from the floodplain by meander migration is re-deposited near the inner bank.  In a graded stream, the residual is nearly completely balanced by floodplain deposition.  The second element is a numerical model which allows the channel and floodplain to co-evolve in response to the entire floodplain hydrograph.  The analysis illustrates, for example, how a floodplain that has been mined for sand recovers by deposition.  The third is a broad-brush formulation, according to which floodplain deposition is assumed to keep pace with channel deposition at long time scales.  This third element allows modeling of the response of large sand-bed rivers to sea-level rise.

Major accomplishments:

Papers
Lauer, J.W., and G. Parker (in review), Modeling framework for sediment deposition, storage, and evacuation in the floodplain of a meandering river, part I: theory, Water Resources Research.

Lauer, J.W., and G. Parker (in review),  Modeling framework for sediment deposition, storage, and evacuation in the floodplain of a meandering river, part II: application to the Clark Fork River, Montana, Water Resources Research.

Lauer, J. W., and G. Parker (in press), Net local removal of floodplain sediment by river meander migration, Geomorphology.

Lauer, J. W., G. Parker, and B. Dietrich (in press), Response of the Strickland and Fly River confluence to post-glacial sea-level rise, Journal of Geophysical Research Earth Surface.

Akamatsu, Y., et al. (2006), Effect of sea level rise on rivers flowing into the ocean: application to the Fly-Strickland river system, Papua New Guinea, in River, Coastal, and Estuarine Morphodynamics: RCEM 2005, edited by G. Parker and M. H. Garcia, pp. 685-695, Taylor & Francis Group, London.

Lauer, J. W., and G. Parker (2006), Response of a simple channel network to post-glacial sea level rise, in River, Coastal, and Estuarine Morphodynamics: RCEM 2005, edited by G. Parker and M. H. Garcia, pp. 697-707, Taylor & Francis Group, London.

Lauer, J. W., and G. Parker (2005), Net transfer of sediment from floodplain to channel on three southern US rivers, paper presented at Proceedings of the ASCE World Water and Environmental Resources Congress, Anchorage, AK, May 15-19.

Lauer, J. W., and G. Parker (2004), Modeling channel-flood co-evolution in sand-bed streams, paper presented at Proceedings, EWRI World Water and Environmental Resources Conference, ASCE, Salt Lake City, UT, June 28-July1.

Tool
Stream Restoration Tools by J. W. Lauer:
Bank Stabilization Diagnosis Tool
Planform Statistics Tool