Streambank erosion assessment in non-cohesive channels using erosion pins and submerged jet testing, Dallas/Fort Worth, Texas.
The objective of this research was to determine if a submerged jet test could be used to predict the erodibility of non-cohesive streambank materials. The study area was the Dallas-Fort Worth Metroplex located within the Blackland Prairie, Texas. Streambank erosion rates were monitored for an eight month period in a 90 sq. km. watershed using erosion pins and water level data loggers. Five study sites, with drainage areas ranging from 3-41 sq. km, were monitored, and submerged jet tests were performed on six samples of original, undisturbed bank material. Field monitoring produced cumulative erosion losses of 27-150 mm over the study period. Submerged jet test erodibility coefficient values ranged from 0.0019-0.0345 cm/hr/Pa for field saturated and field dried samples. The submerged jet test results, adjusted for flow duration and associated applied shear stress, were within 38-47 percent of the field erosion. This corresponds to an overall error of plus or minus one centimeter over an eight month period. This study is the first to compare submerged jet test results to monitored field erosion rates in non-cohesive streambank materials.