In order to easily and rapidly establish low-cost grazing grasslands using centipedegrass (Eremochloa ophiuroides (Munro) Hack.) (CG) on abandoned cultivated land, the influences of slope direction and angle on the covering speed of CG were investigated. We established 61 quadrats at varying slope directions and angles, and the planting of CG was performed in 2003. The covering speed of CG was investigated from 2003 to 2008, and the years of point of inflection (YPI) was calculated. The most rapid YPI was 1.0-1.5 years in the quadrats in the S5°W direction with 0 degree slopes, while the slowest YPI was 3.0-3.5 years in the quadrats in the northern direction with 10-20 degree slopes. Therefore, grassland renovation using low quantities of CG seeds, which are sold at a high price in Japan, is favorable on land in the southern direction and with a lower slope.

In this study, the effect of slope length and angle at the entrance to fishing pots on the size of captured shrimp was examined to determine the optimal design of pots for use in Hokkaido, Japan. The purpose of the current study was to optimize the design of shrimp pots to allow greater control over the size of captured individuals for the purposes of shrimp resource management. Tank experiments were conducted to determine the optimal slope length and slope angle by analyzing the sizes of shrimp entering 10 model pots with combinations of five different slope lengths on slope angle of current shrimp pot, and five different angles on slope length of current shrimp pot. The results showed that, as the slope length of the pot increased, the size of individuals which entered the pot increased. In addition, as the slope angle was elevated in each of the five different slope angle treatments, the size of individuals entering was also increased.

The propagation of water waves over irregular bottom bathymetry and around islands involves many process-shoaling, refraction, energy dissipation and diffraction. Numerical model in this study is developed with the mild slope equation to investigate wave transformation in water of varying depth and combined waves and a current. The method used is splitting method and minimax approximation. The numerical method used in this study is Crank-Nicolson scheme in the FDM. This model is applied to Vincent shoal and compared with laboratory experimental data. The results agreed well with laboratory data. Current effect is considered in this study. This model can be used for the estimation of rip current in the slowly varying topography.