Hillslope Geomorphology and Sediment Budgets Professor Pasternack
HYD252 Spring 2001
EXPERIMENT 1: HILLSLOPE GEOMORPHOLOGY
Background: Hilly and mountainous landscapes are partially to completely covered with soil
under a wide range of erosion and uplift rates, bedrock type, and climate. The major processes
that occur on a hillslope include soil creep, erosion by surface overland flow, and landslide.
Which of these dominates on any part of a hillslope depends primarily on topography, and is
now predictable thanks to major advances in geomorphic theory. The significance of this
prediction capability for reducing landslide damages is of particular value here in northern
California.
Objective: Determine which geomorphic processes are most significant on a Coastal Range
hillslope.
Procedure:
A. Topographic survey using GPS
A high quality digital topographic map is required to assess hillslope dynamics.
1. Use the real-time differential-correction GPS to map the {x,y,z} coordinates of the
hill.
2. Be sure to make a point measurement once every 2 m (6’). Each point measurement
should last for 15 seconds.
Equipment Needs: Trimble Pathfinder Pro XRS
B. Slope mantle characterization
1. While taking point measurements with the GPS, record the type of surface as
“bedrock”, “fine colluvium”, or “coarse rubble” using the data dictionary function.
C. Channels
1. Make a field sketch of the channel network.
2. Use field indicators to guesstimate where the channel begins, and be sure to GPS that
point.
D. Landslides
1. Make a field sketch showing the locations of any landslide scars.
Data Analyses:
1. Make an x,y plot showing the locations of all GPS points.
2. Use MS Excel to make a table of the basic statistics (including mean, standard deviation,
minimum, maximum, etc) of elevation and slope mantle data.
3. Use the program Surfer 7.0 to make a topographic map from your GPS data. Be sure to
print out both a surface “mesh” map as well as a standard “contour” map.
4. Plot a longitudinal profile of a hillslope nose and a valley. Make sure the nose is actually
