subdrainage

The karst depression belongs to the accumulative area of surface water and subdrainage area of subsurface water, the karstification is relatively week, and reservoirs are undeveloped.

溶斜坡和溶洼地为地表水汇集区及地下水排泄区，溶作用相对较弱，储层不发育。

This method can acurately simulate the flow direction in gird near river, and can keep the direction of waterflow from crossing the watershed of subdrainage area.

这样既可以较确地反映出河道附近格网水方向，又可以让各个子内汇方向和水方向不会跨越子分水岭。