GSA Annual Meeting in Indianapolis, Indiana, USA - 2018

Paper No. 206-14
Presentation Time: 4:55 PM

IMPROVING SOURCE-TO-SINK SEDIMENT TRANSPORT ESTIMATES BY MERGING BIG DATA AND THE FULCRUM APPROACH TO BETTER UNDERSTAND FLUVIAL PROCESSES


WILSON, Nicole, School of Geology, Energy and The Environment, Texas Christian University, Fort Worth, TX 76129 and HOLBROOK, John, Department of Geological Sciences, Texas Christian University, Fort Worth, TX 76129

To create useful basin models for stratigraphic systems it is critical to accurately quantify source-to-sink sediment flux, but most methods require data not readily attained by common subsurface studies and all methods are hindered by low precision. In the Fulcrum approach variables of channel bankfull thickness and grain size are used to calculate sediment bankfull discharge to derive an annual sediment volume. While using commonly collected data the Fulcrum approach similarly yields only approximate flux estimates. To improve the precision of the calculated source-to-sink estimate for long basin durations, the bankfull duration of the fluvial systems and the annual proportion of sediment discharged during this bankfull flow must be determined. Through categorization of fluvial systems by attributes such as catchment area and paleoclimate at the time of discharge a more specified and accurate bankfull flow duration and total bankfull sediment discharge is estimated. The RAFTER database stores and categorizes these data for over 500 streams worldwide. Using daily stream gauge data spanning decades in conjunction with measured bankfull values from literature the database can derive stream specific data attributes including bankfull duration. Evaluating stream gauge data for modern fluvial systems according to groups such as climate setting this bankfull flux searchable database is also a useful tool for identifying analogue stream data scaled to catchment area and channel dimensions. Leveraging data from modern rivers the database can yield more accurate values for duration at bankfull flow and sediment discharge at bankfull which can be used as an analogue for stratigraphic rivers with interpreted climate and size parameters. Significant breakdowns in bankfull duration are shown, with bankfull duration in arid and temperate dry season rivers on the order of a fraction of day per year, wet temperate climates tending to be an order of magnitude longer and boreal climates longer still. Sediment transport estimates from source-to-sink can be improved by a geometric factor by categorizing stratigraphic rivers by known parameters such as climate.