THE INFLUENCE OF LABORATORY SCALE TIDES ON DELTA MORPHOLOGY

Modern-day deltas are some of the most fertile land on the planet, and as a result are heavily populated. Rising sea levels and changing climate all but guarantee dramatic coastal change, therefore understanding and predicting the response of deltas to these and other processes is critical. Our understanding of how deltaic systems behave in the field is, however, hampered by their large size and slow response as well as by the many factors that control their morphology. Sediment and water discharge, grain size, and sea level may be independently manipulated in deltas generated in a laboratory, and their effects studied individually, which is impossible in field scale systems. Such deltas are smaller than their counterparts in the field and evolve more rapidly, but some subtleties of both the delta response and the formative processes are lost. A system was developed that simulates tides in their most basic sense: rapid, shallow cycles in base level. Preliminary results indicate that features such as tidal channels form under these conditions, albeit with complexity constrained by the size of the system. Results suggest that it is not necessary to recreate the full complexity of the process for prediction of large features and gross morphology, and the likely response to change.