Sound BASIS for Relating Sediment Flow,
Stream Health By Luis Pons
In their version of "keeping an ear to the ground," scientists
at the Agricultural Research Service's
Sedimentation Laboratory in Oxford, Miss., are finding ways to diagnose
watershed health and stability by keeping a high-tech "ear" in the water.
ARS hydraulic engineer
Roger Kuhnle is leading efforts at Oxford to use updated acoustic technology to
monitor concentrations of sediment flow within water systems. With this
technology, he's "listening" for clues that could indicate changes--and
problems--in these water systems.
The project is being done with the
University of Mississippi on a model
stream channel at the lab's
Watershed Process Research Unit and in nearby Goodwin Creek.
The project has led to development by the university, in
collaboration with ARS, of the Bedform and Sediment Information System (BASIS).
This monitoring method emits a pulse of acoustic energy and gauges the strength
and travel time of the echo to detect and measure sediment's location and
Like its predecessor, BASIS locates sediment on a stream's
bottom, which can indicate sediment erosion or accumulation. But what makes the
new system novel is that it can also detect sediment suspended in water.
BASIS converts acoustic data into a digital image showing
suspended sediment as a cloud, in a multitude of colors signifying
concentrations. Its main unit is compact, and the entire system can run
remotely from a laptop computer.
Accurate determinations of sediment flow are needed because
sediment can reduce reservoir capacity, fill channels and cause flooding,
degrade water quality and destabilize channel banks. Researchers say physical,
chemical and biological damage associated with sediment flow in North America
costs around $16 billion annually.
Kuhnle says BASIS technology is now available for use by private
firms and government agencies. More sophisticated technology for total
suspended-sediment load sampling should become available after up to five more
years of experimentation and testing.
Read more about this research in the October 2003 issue of
Agricultural Research magazine.
ARS is the chief scientific research agency of the
U.S. Department of Agriculture.