2011


Britton Mosley, Jr.

Britton Mosley, Jr.


Years participated in RESESS:
2011


POSTER
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An Overview

Academic Affiliation: Jackson State University

Science Research Mentors: Greg Tucker, CU & Francis Rengers, CU, USGS
Writing and Communication Mentor: Mariela Perignon, CU
Coach: Tim Reeme, UNAVCO


Biography

Britton grew up in the warm, humid climate of State Line, Mississippi where nature was his playground. As a child he remembers massive, noisy oil and gas drilling rigs collecting natural resources. Observing these processes sparked an inquisitive love of science. Britt feels that he did not pursue geology, but that geology pursued him. Britt recently transferred from Jackson State University to the University of Southern Mississippi located in Hattiesburg, where the Leaf River flows on its way to the Gulf of Mexico. When he is not studying, he explores nature by going hunting, fishing, and spending time with friends and family.


Abstract

Factors controlling infiltration rates in a semi-arid landscape

Agricultural landscapes in semi-arid regions are often prone to gully erosion. Understanding rates and patterns of gully erosion requires documenting the driving hydrology, and in particular quantifying the capacity of soils to generate runoff during summer convective storms. Here we report measurements of soil infiltration capacity at a study site, known as the West Bijou Creek escarpment, 40 miles southeast of Denver. Rapid gully network propagation at this site appears to be driven mainly by head cut retreat during flash floods. Using a double-ring infiltrometer, measurements of infiltration rate were collected across a variety of soil and vegetation types to determine the degree to which factors such as vegetation, slope steepness, soil porosity and permeability influence soil infiltration capacity. We measured infiltration capacity in 15 different locations and observed infiltration rates ranging from 40 to 400 mm/hr. In general, the hill- slopes were less permeable than valley floors. Hillslope infiltration capacity was in the range of 40 to 70 mm/hr. Valley floors on the landscape show greater variability in the saturated infiltration capacity, with rates ranging from 70 to 320 mm/hr. Surprisingly, areas that are underlain by sandstone and shale show similar infiltration rates. At the study site, rainstorms with a 10-minute peak intensity above 60 mm/hr are capable of producing overland flow; such storms typically occur several times a year. The data suggest a conceptual model in which most runoff is generated on hillslopes, and the resulting flow routed through valley networks drives rapid erosion, sediment transport, and head cut retreat.