Part of my dissertation research involves the measurement of soil
erosion rates from forest roads in the Virginia Piedmont. All of the road
segments in this study are located at the Reynolds Homestead Forest Resources
Research Center in Critz, VA. The objectives for this particular study are to quantify
soil erosion rates from forest road approaches to stream crossings and to
compare these measured erosion rates with soil erosion model estimates from the
Universal Soil Loss Equation (USLE) and the Water Erosion Prediction Project
(WEPP). This study will provide valuable soil erosion data for a major source
of stream sedimentation and for the calibration and evaluation of WEPP.
Field work started off a few weeks ago with the help of a lesson
in using the total station from Dr. Michael Aust. The total station enables us
to obtain precise measurements of road length, slope, and surface area. We will
also use the total station to measure monthly changes in elevation of a
sediment depositional area created by a sediment trap (i.e. silt fence) located
at the base of each road study plot. Study plots are bounded
at the top of the hill by a water bar, at the side by an insloped road surface,
ditch, and berm combination, and at the bottom by a sediment trap. After
getting the hang of the total station, FREC junior and Reynolds Homestead
Intern, Drew, and I surveyed 15 road segments for this study. Nine of these
segments will be used to measure monthly soil erosion rates and six will be
used to measure soil erosion during rainfall simulations. This survey data will
be valuable in interpreting soil erosion results and in calibrating the WEPP
model. Slope and length data have already been used in USLE soil erosion
estimates.
This week, FREC M.S. students Laura Wear and Chelsea Curtis helped
me to dig trenches and install the nine silt fences. Reynolds Homestead Project
Manager, Clay Sawyers, provided impressive bulldozer work in “re-opening” some
bare forest roads and re-shaping some roads that were later graveled. Laura,
Chelsea, and I followed up Clay’s treatment installation with the silt fence.
For the monthly erosion part of this study, we have four recently graveled road
segments and five recently re-opened bare road segments. Upcoming work includes
getting initial elevation measurements of the sediment depositional areas and
installing open-top box culverts for use at the rainfall simulation sites. More
updates will follow! In the meantime, feel free to check out some pictures of
field work so far: http://www.flickr.com/photos/64188209@N08/sets/72157627350514228/
Additional pictures can be found on our Group Flickr site. See the link on the bottom right of the blog page.
Thanks,
Kris