Research Of Automatic And Real-time Monitoring Technology For Seabed Erosion And Deposition

Monitoring of seabed erosion and deposition is significant to coastal research and protection. These phenomena are related to the stability of coastal construction, near shore ecological balance, transportation of sediment, etc. Funded by the National High Technology Research and Development Program of China (863 Program) (Contract No.2008AA09Z109), this study aimed to design an automatic and real-time monitoring system for seabed erosion and deposition to support the research of seabed sediment.This research started from the review of the current seabed erosion or deposition monitoring technologies. After analyzing the advantage and disadvantage of these techniques, we detailed the new designed monitoring system, particularly introduced the data processing method and test experiments.Firstly, the paper listed the current seabed erosion and deposition monitoring technologies and the related theoretical background. Then we proposed the idea that using electrical resistivity probe to monitor seabed progress and detailed the characteristics of the probe.Secondly, on the base of in-situ monitoring request, the new designed seabed erosion and deposition monitoring system was detailed. This new system was composed of an electrical resistivity probe, the measurement controlling device, controlling vessel, GPRS model, float ball, solar power supply device, global position system, tripod, matched software, etc. The formation and the force condition of each part were considered and optimized.Thirdly, this paper mainly introduced the data processing method based on the monitored electrical resistivity profiles. The popular threshold value method, curve fitting method, locality abrupt point analysis method, and wavelet analysis method were compared and the last two were selected to analyze the resistivity data. Proper data processing software was introduced and relevant progress was compiled. This work enhanced the automatic performance, improved the processing accuracy and efficiency.Finally, both indoor and in-situ experiments were performed to test the effectiveness of the new designed monitoring system and the data processing methods. Through the experiments, the electrical resistivity properties of different sediments were achieved which can help the later data processing. The experiment results indicated that this system was capacity to work in situ for long time and automatically transmit current data to the laboratory; the data processing method and software can help to interpret the water-sediment interfaces correctly and efficiently. The experiment results can support the sediment monitor and research.A new seabed erosion and deposition monitoring system was designed and proposed in the paper. It can be remote controlled and automatically work in situ for long time. The monitored electrical resistivity data was properly processed to get the accurate water-sediment interface positions. This research enriched the seabed erosion and deposition monitoring technologies and made a crucial step for long time and unattended monitoring. This new system showed a wide and broad prospect.