An Instrument With Constant Volume Approach for In Situ Measurement of Surface Runoff and Suspended Sediment Concentration

Abstract

There is an increasing demand for reliable methods to measure soil loss in order to get a better understanding of sediment movement and to develop process‐based sediment transport models. This study described the design, calibration, and practical application of an instrumented technique that automatically characterized surface flow in situ fields. The instrument consisted of a sampling assembly, a measuring assembly, and a management platform. The special design combined with a volume‐mass conversion relationship was used to determine the exact volume and mass of the sediment‐laden water, thereby allowing the implementation of real‐time measurement and synchronous calculation of runoff rate and sediment concentration. Calibration results showed that normal distributions and an average error of −3.67% were obtained for the target sediment concentrations of 2–1,000 g/L. Compared with the gravimetric method, the average error of the new technique for sediment concentration was 4.82%, and the highest precision was 98.50%. The high repeatability and accuracy of the technique suggest that it can be used with confidence to give satisfactory results in fields. A field experiment under natural rainfall showed that a grass‐covered plot had 18.94% less runoff rate and 42.92% lower sediment concentration than a bare soil plot, illustrating the impact of vegetation cover on reducing soil loss. This uniquely designed instrument provides a new approach to real‐time sediment detection in surface flow. It will be beneficial for rigorously evaluating runoff and sedimentation and for in‐depth research regarding water and soil loss processes.

Developing an automatic collector of runoff for studies using rainfall simulators

“…The volume of 200 cm 3 was adopted as the criterion for both taking the readings and storing the data, as it is the same as the minimum height needed for the collected runoff to completely cover the turbidity sensor. Similar architecture for a runoff collector is presented by Zhan et al (2021).…”

“…Technological advances and the ease of obtaining electronic devices have boosted research and the development of equipment in various areas of science (Kumar et al, 2021;Macedo et al, 2021;Zhan et al, 2021). The use of devices to evaluate hydrological and soil erosion processes has increased in the last years, for instance rainfall simulators, which began to be employed in 1930s and are currently widely used (Salem & Meselhy, 2020).…”

“…Even though there is research in the area of developing collectors for runoff (Zhan et al, 2021), there is no specific model for field use that measures and stores the runoff volume and sediment loss in tests with simulated rainfall.…”

A device to collect passive, flow‐weighted water samples from surface runoff

“…They also require a power source, limiting their ability to be deployed remotely, though solar panels can be effectively used in some instances (Burcham et al, 1998;Cullum et al, 1992). Zhan et al (2021) created a sequential sampler that uses an automated flushing mechanism to prevent sediment clogging. However, the mechanism can result in sample contamination and does not allow for continuous sampling.…”

“…Zhan et al. (2021) created a sequential sampler that uses an automated flushing mechanism to prevent sediment clogging. However, the mechanism can result in sample contamination and does not allow for continuous sampling.…”