The Impact of Providing Surface Cover on the Soil Loss and Water Discharge under the Moderate Rainfall Event

摘要

A nation’s development purely relies on the good road infrastructure which is necessary to promote the economic growth of the country. On the other side, the detrimental effects in the form of soil loss caused by its construction cannot be neglected. Roads, regardless of their small areal periphery are equally responsible to induce higher rates of erosion when compared with the agricultural lands. This study aimed to shelter the exposed soil surface once the gradients are constructed to mitigate undesirable siltation which raises water muddiness and worsens water carrying capacity of the stream channels. To cope with this issue a full scale field test was conducted on three plots which resembles the road embankments (~30°) provided with the different percentage of land covers i.e. Plot A (fully grass covered surface), Plot B (bare surface), and Plot C (50% of the grass covered surface). The soil loss examined was sandy loam. The sediment loss was observed manually at the catchment outlet of each plot whereas, the volume rate of water flow was observed in the designed bottom container. The runs were conducted for 2 hours under the simulated rainfall events of 52 mm hr-1. The impact of simulated rainfall on the soil loss was nullified by Plot A, the soil loss was severe for Plot B, and Plot C showed preeminent results in restricting soil from flowing away. Whereas, the values of water discharge were found varying for all the plots at different time intervals which are further discussed in this paper. Keywords: erosion by water, water discharge, exposed soil surface, land cover, simulated rainfall