Field measurememts of lake currents in Lake Suwa by means of ADCP

Abstract

Numerous studies in biological and chemical processes have been conducted in Lake Suwa, only a few of which were concerned with physical processes that strongly affect a lake' s biochemical dynamics. To gain a better understanding of the corresponding physical dynamics (e.g., current pattern and discharge), we deployed an updated current instrument (i.e., an Acoustic Doppler Current Profiler, ADCP), which is accepted world ･ wide for its accuracy and high resolution as well as for its ability to resolve the spatial and temporal variations of currents. Using the ADCP, we measured discharges of the dominant inflows and current patterns of a submerged macrophytic area near the shore together with an outflowing area (nearby Kamaguchi floodgate). Our results show that (1) the discharges observed in the dominant inflows (the Kami, Miya and To rivers) are different from those reported by Nagano Prefecture, whereas the outflowing discharge at Kamaguchi Floodgate is similar to that in the Nagano Prefecture report, and (2) the vertical distributions of velocity outside the submerged macrophytic area differ from those inside the area, whose horizontal velocities were reduced by macrophyte-induced turbulence, and (3) the current patterns near the outflow showed a strong velocity in the northeast, rather than in the southwest region.

Extraction and analysis of surface lake flow direction in Poyang Lake based on texture enhancement and Hough transform

“…Lake flow is of great significance to lake ecological environment and can provide technical support for lake water environment and wetland ecological monitoring, water resources development and waterway traffic construction (El-Manadely et al 2017;Khwairakpam et al 2019;Wang et al 2021). At present, the conventional method to obtain lake flow is mainly to set up stations for on-site measurement (Toyota et al 2010) and obtain lake flow information through hydrodynamic numerical simulation. Although these methods have achieved good results in the study of lake flow, the deployment cost of manpower and material resources is high when the research scope is large, and more data support is needed, which is slightly insufficient in terms of timeliness.…”