DEVELOPMENT OF WATER QUALITY OBSERVATION SYSTEM IN SHALLOW WATER USING A QUADMARAN AUTOMATED VESSEL

Abstract

 The quadmaran automated vessel was applied to the water quality observation in Hichirippu Lagoon, Hokkaido, Japan, and simultaneously, mooring array was conducted. We developed propeller guard to achieve automatic navigation in the shallow lagoon at a depth of 0.7 m under the condition of luxuriant water plants. Then, detailed water quality distribution was observed by the mooring arrays and wide-area observation conducted by the vessel. The low-salinity water was confirmed in the lagoon head during the long time due to the freshwater supply and heat exchange by solar radiation on the sea surface. In contrast, the low-salinity water at the lagoon mouth was affected by the water exchange of low-temperature and high-salinity water from the open sea. Our observation suggested that the distribution of water temperature and salinity dynamically fluctuates in the areas from the lagoon mouth to the central part.