75 Ground Penetrating Radar Applications in the Earth Sciences and Archaeology (Posters)

Tuesday, 21 March 2017
1:30 PM - 5:30 PM
Urban, 17th Floor

SEDIMENT STORAGE ON A 1ST ORDER STREAM FLOOD PLAIN USING GPR

Paper number: 75-1
Program: Theme Sessions
Time: 1:30 PM – 5:30 PM

Authors

Abstract

Sediment storage and deposition on 1st and 2nd order stream channels has been a growing area of interest in the mid-Atlantic due to sediment and nutrient loading challenges in the Chesapeake Bay. Our study involves a small 1st order gravel bedded stream surrounded by farms with an easily identifiable flood plain. Using hand dug test pits and a 100mhz GPR, we found there is a relatively uniform gravel layer across the entire flood plain. We interpret this layer to represent conditions following the last glacial maximum. This layer suggests a broad multi channelized stream system which is a distinct contrast to the present1st order, incised meander system. We used ArcMap to digitize the study area and calculate both the area of the flood plain and the surrounding farm fields. This allowed us to determine the volume of sediment stored and provided a rough estimate of the soil denundation across the adjacent farm field. The total volume of the clay and silt sized sediment stored on top of the gravel layer in our study area is 1414 m3 which corresponds to a vertical loss from the adjacent farm field of 6.4cm. Field edges that are believed to represent pre-agricultural surfaces support erosional loss of up to 1m of topsoil in the surrounding catchment. Our results indicate that the amount of sediment stored on the flood plain is significantly lower than other 1st order stream systems and that the majority of the sediment eroded off the farm fields is transported downstream.

Geological Society of America Abstracts with Programs. Vol. 49, No. 2

doi: 10.1130/abs/2017NE-290252

© Copyright 2017 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.