Runoff and Sediment Yield Modeling of Meki River Watershed Using SWAT Model in Rift Valley Lakes Basin, Ethiopia

Aman Bunta,Brook Abate

doi:10.11648/j.ajce.20210905.12

Abstract

Loss of soil fertility in agricultural lands and sedimentation in lakes of central rift valley of Ethiopia are major watershed problem threatening the agro economy in the area. To develop effective erosion control plans through implementing appropriate soil conservation practices, runoff and sediment yield in Meki watershed was estimated and analyzed using the SWAT model. The model showed the simulated mean annual surface runoff was 114.03mm and the mean annual streamflow was 9.41m<sup>3</sup>/s. Similarly, mean annual sediment load of 13.12 t/ha enters to Lake Ziway. The model was calibrated and validated on daily and monthly time step for flow and on monthly time step for sediment yield. The results of Nash Sutcliff Efficiency of 0.71 on daily and 0.89 on monthly time steps for streamflow and its value of 0.80 on monthly time step for sediment yield during calibration showed that there is a good match between measured and simulated data for both variables on daily basis and very good match on monthly basis. The potential erosion source areas were identified. Likewise, 51.34% of the watershed area was found to be potential erosion sources and priorized for erosion control plans.

Highlights

This study was conducted to characterize the Meki River watershed in terms of spatial distribution of sediment yield in order to prioritize the sub-basin areas which need watershed management by using current SWAT model version 2012
The model over estimated simulated flow by 6.5% and 12.0% in both calibration and validation periods respectively yield in Meki River watershed
A good performance of the model in the Validation period indicates that the fitted parameters during calibration period can be taken as a representative set of parameters for Meki watershed

Summary

Introduction

The severity of soil erosion is caused due to the both of natural effects such as aggressive climate, steep topography and erodible soil type and human activities such as land clearing for agriculture and overgrazing, firewood stripping has resulted in a rapid acceleration of soil erosion [2]. This condition is being escalated in Meki River watershed in particular and rift valley lakes basin in general. Soil erosion and nutrient losses are recognized to be severe threats to the national economy of Ethiopia and leads to food insecurity [3]

Objectives

Methods

Results

Conclusion