Effect of Aquatic Plants on Water Qualities in Small Closed Waters

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Kunihiko Hamagami, Chihayu Murakami

Tuesday 30 june 2015

12:48 - 12:51h at Europe 1 & 2 (level 0)

Themes: (T) Water engineering, (ST) Computational methods, Poster pitches

Parallel session: Poster pitches: 5E. Engineering - Computional

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In some closed water bodies, the fluid flow tends to stagnate because of insufficient inflow and outflow. The water quality purification which uses an aquatic plant is proposed in a closed water body. To make use of the method in the body with floating aquatic plants, we have to transport from bottom to surface the nutritive salt which accumulate at the bottom of the body. When we apply the aquatic plants for the water quality purification in a closed water body, firstly, it is important for us to comprehend what the aquatic plants influence in the body. In this study, a field observation was conducted in order to consider the effects of the abundance of aquatic plants on the water quality and water flow in a small water body, such as an agricultural pond. As the results, it is reveals that the fluid exchange was performed by thermal convection between the area with and without an abundance of vegetation at nighttime. Then, though the nutrients decreased due to the absorption and adsorption from the vegetation during the flowering period in the summer, these nutrients increased in reversal due to the elution from the bottom of water body after the vegetation decayed in the winter. From the above results, it can be concluded that aquatic plants should be adequately controlled to exert its effect sufficiently on the eutrophied water body.