地盤沈下地帯における内水排除過程の計算

Abstract

1km mesh data base on land information of Aichi prefecture was used to calculate the inland water flow during the storm in low and flat small basins in Nikkohgawa area. The area has been suffering from land subsidence. The numerical calculation of water flow was executed on the 1km mesh basis. Manning's formula was used to calculate the flow rates of each mesh from or to the neighboring meshes during a time step. The comparison of the calculated and recorded maximum water levels during a storm in 1976 suggests that the equivalent Manning's coefficients of roughness outside the creek might be far greater than the coefficients in the creeks, as has often been pointed out. The altitudes in 1960s in a basin which has pumping stations at the downstream end to drain water from it were estimated from the result of leveling being put in practice annually. The calculation of drainage process using these estimated altitudes was done to know what might have happened if the subsidence had not occurred. This kind of calculation would be useful to examine the water drainage planning in a subsiding flat basin.