The washout on Incision cliff is a serious problem. Incision cliff if not carefully done, can contribute to soil erosion md, by removing covering plants could have a large impact on the temporary of normally the quality of water Because the washout of soil is influenced by its surface, it is necessary to prevent or diminish soul particle by plantation of grass species. Kumerowia stipujacea Is an useful species that diminish the injury of soil and rainwater We study that estimates of preventing soul erosion and river over-flow can be obtained from the experimental model developmented by several equators. Many potential contaminants are removed by filtration as the water moves slowly through the fields of K. supulacea.