Abstract
Waterfront activities in rivers and ponds have increased, and ensuring the safety of facilities is an increasing problem. To prevent slip accidents on the bottom of waterfronts, the coefficient of slip resistance (C.S.R') was evaluated quantitatively. The following conclusions were obtained by investigating the relationships between the amount of attached algae, C.S.R', the growth factor of algae and the use of water-friendly structures to prevent slipping. The first is a negative correlation between the amount of attached algae and the C.S.R' of the water bottom; thus the water bottom becomes slippery with the growth of attached algae. The second is that when the nutrient concentration in water is lower than the half-saturation constant, there is a positive correlation between the flow velocity and the amount of attached algae. In contrast, when the nutrient concentration is higher than the half-saturation constant, there is a positive correlation between the light intensity and the amount of attached algae. Therefore, it is possible to create a nonslip condition on the water bottom by managing the nutrient concentration, light intensity and flow velocity. The third is that the water bottom becomes slippery with the growth of attached algae regardless of the type of material.
