Department of Earth and Environmental Science

Meredith D. Reitz

Department of Earth and Environmental Science
University of Pennsylvania
240 S. 33rd Street
Hayden Hall
Philadelphia, PA 19104-6316

Office:  2C19 David Rittenhouse Laboratory
Lab:     56 Hayden Hall

Phone: (215) 746-3203   (lab)
Email: mreitz@sas.upenn.edu

Education

2007-present: Ph.D. candidate, Physics, University of Pennsylvania
2002 -2007:   B.S., Physics, with minors in Math, Astronomy, English, & Political Science, Arizona State University, Barrett Honors College

Graduate Advisor

Dr. Douglas J. Jerolmack (University of Pennsylvania)

Awards and grants

Publications

Reitz, M.D., and D.J. Jerolmack (2011), Experimental alluvial fan evolution: channel dynamics, slope controls and shoreline growth. In review, J. Geophys. Res.– Earth Surf.

Limare, A., M. Tal, M.D. Reitz, E. Lajeunesse, and F. Métivier (2011), Optical method for measuring bed topography and flow depth in an experimental flume. Accepted, Solid Earth.

Jerolmack, D.J., M.D. Reitz, and R.L. Martin (2011), Sorting out abrasion in a gypsum dune field, J. Geophys. Res., 116, F02003, doi:10.1029/2010JF001821.

Reitz, M.D., D.J. Jerolmack, R.L. Martin, and R.C. Ewing (2010), Barchan-parabolic dune pattern transition from vegetation stability threshold, Geophysical Research Letters, 37. doi: 10.1029/2010GL044957.

Reitz, M.D., D.J. Jerolmack, and J.B. Swenson (2010), Flooding and flow path selection on alluvial fans and deltas, Geophysical Research Letters, 37. doi: 10.1029/2009GL041985.

Research presented

Reitz, M.D., and D.J. Jerolmack (2011, March). Thresholds, memory and self-similarity on river deltas. Talk presented at American Physical Society annual conference, Dallas, TX.

Reitz, M.D., D.J. Jerolmack, R. Martin, R. Ewing, and D. Bustos (2010, December). Predicting the effect of changing vegetation conditions on aeolian dune landscapes. Talk presented at American Geophysical Union annual conference, San Francisco, CA.

Jerolmack, D.J., and M.D. Reitz (2010, December). Growth of river delta networks: Thresholds, periodicity, aging and self similarity. Talk presented at American Geophysical Union annual conference, San Francisco, CA.

Jerolmack, D.J., R.L. Martin, C. Paola, M.D. Reitz, and R. Schumer (2010, December). Linking stochastic sediment transport to physical processes. Talk presented at American Geophysical Union annual conference, San Francisco, CA.

Reitz, M.D., and D.J. Jerolmack (2010, September). Thresholds, memory, and self-similarity: building sediment dispersal systems. Talk presented at Geological Society of London William Smith Meeting, London, England.

Jerolmack, D.J., and M.D. Reitz (2010, April). Flooding, flow path selection and growth of alluvial fans and deltas. Talk presented at European Geoscience Union annual conference.

Reitz, M.D. (2010, March). Self-organization and evolution of a river delta. Talk presented at University of Pennsylvania Art of Research Graduate Symposium, Philadelphia, PA.

Reitz, M.D., and D.J. Jerolmack (2009, December). Modeling dynamics of channel reoccupation on alluvial fans. Poster session presented at American Geophysical Union annual conference, San Francisco, CA.

Reitz, M.D., D.J. Jerolmack, Martin, R., Ewing, and D. Bustos (2009, October). Competing effects of sediment flux and vegetation on dune morphology. Poster session presented at the annual Binghamton Geomorphology Symposium, Blacksburg, VA.

Reitz, M.D., D.J. Jerolmack, and E. Moberg (2008, December). Channel dynamics of experimental alluvial fans with a bimodal grain size distribution. Poster session presented at American Geophysical Union annual conference, San Francisco, CA.

Current research

Channel dynamics on alluvial fans
Experiments:
    In a tank in our Sediment Dynamics Laboratory, we build experimental alluvial fans with varying fractions of a strongly bimodal grain size mixture.  We feed sediment and water at a constant rate into the tank, and observe the emergent dynamics.  Our data collected is in the form of overhead images taken every two minutes and periodic topographic scans with a laser.
    After the fans reach a minimal size for a dynamic equilibrium, we observe a robust channelization sequence (see the four images below – white is where water is, and dark gray is the fan).  First, the system will undergo strong channelization, and concentrated deposition at the shoreline will prograde the shore, to a point where the slope is lowered enough that this is no longer a favorable route off the fan.  Deposition within the channel will then increase back up onto the fan, until at some point the route is unfavorable enough that the system breaks into a flooding phase, in which it ‘searches’ for a new globally favorable route.  It chooses a new channel and the sequence repeats.

Our analysis of these dynamics has included measures of: the timescale of this channelization sequence, the way in which the channels fill space, and the observed tendency of channels to reoccupy former paths.

Numerical modeling:
    We can explore the tendency of channels to reoccupy former paths as a system where water paths are directed random walks, but old channels act for some time as absorbing states.

Frequency of visited area, 150 frames of experiment

Fan area visited, colored frequency, anneal time=10, t=2000