Automated erosion wheel: A new measuring device for field erosion plots

ABSTRACT:

For erosion experiments in the field where no electric power is available an automated device for runoff and soil loss measurements was developed. This equipment is designed for continuous runoff measurement from plots up to 6om². The design is similar to a turning wheel with a horizontal axle. The automated erosion wheel (AEW) consists of four equal sections each one holding five liters (1.32 gal) resulting in a resolution for each tip of 0.08 mm (0.003 in) for 6om² plots. The automated erosion wheel is capable of measuring a maximum rate of 75L min⁻¹ (19.81 gal min⁻¹). Each tip is monitored automatically in real time by a data acquisition system. Up to three automated erosion wheels can be connected to one data logger. The whole system is powered by one solar panel. Soil-water-suspension is divided by an adapted multi-tube divisor. About 3.4% of the runoff is sampled in a plastic barrel for determination of sediment concentration and soil loss. At this stage no temporal distribution of sediment delivery can be recorded by the automated erosion wheel. After each erosive rain storm, collectors are emptied and samples are taken to the lab for further analyses. With calibration of the tipping buckets volumes an accurate, time distributed runoff measurement is possible. The maximum error in sediment concentration measurement is 1.1%. Therefore, the chosen multitube device is able to collect representative runoff samples containing same sediment concentration as surface runoff. Each automated erosion wheel system is located in a shed. The automated erosion wheel has been used at three locations in Austria since 1997.