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.

岩溶斜坡岩溶洼汇集区及下排泄区，岩溶作用相对较弱，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.

这样既可以较确反映出河道附近格网的流方，又可以让各个子流域内的汇流方流方不会跨越子流域的分岭。