measure surface roughness, slope anddepression storage in the field. Designed
for digitizing the surface of the landscape at
3.8 cm intervals, it is capable of estimating
depression storage up to 1 meter in length.
The device can be used by a single person and
will stand vertically in the ground, without user
assistance at low windspeeds. The Figure to the
right presents a schematic of the system. In
essence the device consists of a series of wood
dowels that are lowered to be flush against the
ground. The distance the dowel is adjusted to
represents the distance between the ground and
the plane of the bottom of the device. This plane
is parallel to the slope of the ground between the
ends of the device. An adjusted distance of 0
indicates there is no space between the level of
the ground and slope, hence no depression storage.
Displacements greater than zero indicate there is
space between the level of the ground and ground itself. To use, the site of interest is cleared of sticks, vegetation and debris that could prevent the rods from contacting the earth. The device is oriented parallel to the direction of maximum slope and sited so that one or more of the ends are on a topographic high. The device is pushed into the earth on each end using the feet rest at each end. The string is unwound at the downslope end and a line level is used to make the string level. The location on the vertical ruler that the string intersects with is noted This information is used to determine the vertical distance from the axis of the string to the position of the string when the device is horizontal. Simple trigonometry is used to determine the apparent slope of the device. The wood dowels are carefully lowered to the ground and the distance the base of the black tape is located on is recorded. Specialized software has been developed that will use the information from this instrument to determine the %slope, roughness statistics, ideal depression storage, and effective depression storage, defined as the true volume of storage behind microrelief highs on the slope. This software provides storage in mm volume per unit width and per unit length. Thus an effective storage of 6.5 means that the surface can hold the equivalent of 6.5 mm of rainfall without runoff. The software, called ROUGH4.EXE, runs on any Windows PC and requires a single input file with all of the distances measured with the device. A datalog sheet for the device, the software and a sample input file are available for download below.
Click here for a datalog sheet for the device (In Microsoft Word).
Right single click here to download the ROUGH4.EXE software.
Right single click here to download a sample input file.
An extended abstract that describes research related to the device is available here .