Dr. Joel Johnson's research focuses on quantifying active surface processes on hillslopes and in fluvial channels, in order to relate active surface processes to the evolution of topography over both short and long timescales. Common themes include understanding feedbacks in complex geomorphic systems, interpreting relationships between landscape process and form, and separating signatures of external forcing from internal system dynamics. An approach to quantifying surface processes is through environmental monitoring, allowing one directly measure both short-term erosion and deposition and the hydrological forcing (e.g. variability in rainfall, soil moisture content, overland flow and river discharge) that drive the surface processes. For example, in an ongoing monitoring project in southern Arizona, data is collected on rainfall, hillslope overland flow, channel discharge, soil moisture, and soil erosion to better understand controls on arroyo incision rate and patterns. Other current research projects include quantifying how climate gradients in Hawaii have influenced topographic development, measuring forces inside experimental debris flows using custom-developed "smart rocks", understanding controls on flash flood hydrograph shapes and sediment transport rates, and constraining feedbacks between sediment transport rates, sediment sorting and the evolution of bed roughness in mountain rivers.

Areas of Expertise

Process geomorphology, feedbacks between channel morphology and hydrology and sediment transport, landscape sensitivity to climate and lithology, bedrock river erosion, flash floods, arroyo erosion, canyon formation, debris flows, environmental monitoring and sensor networks, laboratory flume experimentation, numerical modeling, tsunami sediment transport and deposition.

Research Locations

Mendenhall Postdoctoral Fellowship - U. S. Geological Survey (2007 - 2009)

John Montagne Award for student research in quaternary geomorphology One of 13 specialized awards out of 555 applicants for GSA student research grants - GSA (2006)

Teaching Assistant Excellence award - Massachusetts Institute of Technology (2004)

MIT Presidential Fellowship - Massachusetts Institute of Technology (2001 - 2002)

Graduate Students

Lindsay Olinde, Ph.D., expected 2014
Interests: Studying fluvial geomorphology, focusing on feedbacks between stream morphology and sediment transport with interest in incorporating hydrologic research into resource management and public policy as well as science outreach education. My dissertation field work focuses on setting up stream monitoring in Reynolds Creek Experimental Watershed, near Murphy, ID. Other field campaigns during my PhD have also included the Kohala Peninsula, HI and the Henry Mountains, UT. Background: My PhD research includes developing technologies to improve bedload monitoring in mountain streams by building and deploying Radio Frequency Identification (RFID) and accelerometer embedded particles and comparing deposition locations with flow modeling. While I am currently studying how water moves coarse sediment, my civil and environmental engineering BS and MS focused on water quality.

Brendan P Murphy, Ph.D., expected 2016
Dissertation Research Topic: The influence of spatially variable climate on landscape evolution, Kohala Peninsula, Hawai'i Research interests include: landscape evolution, chemical & physical weathering, bedrock channels, sediment/soil production, sediment transport, and applications of LiDAR for high-resolution topographic change detection.

Kealie Goodwin, Ph.D., expected 2016
Research Interests: Fluvial Geomorphology, Sediment Transport, Flash Floods, Laboratory Experiments, Ephemeral Channels, Bed Surface Armoring Dissertation: Flash Floods and Unsteady Flows: Sediment Transport, Turbulence, and Bed Surface Armoring (working title) Committee: Joel Johnson, David Mohrig, Wonsuck Kim, Paola Passolaqua, Johnathan Laronne