Abstract:
Land management practices in a given watershed determine the extent of Soil erosion. To mitigate the effect of increasing sediment yield, it is important to identify erosion-prone areas in the watershed. The objective of this study was to identify best management practice options that alleviate soil erosion in the Meki watershed using Soil and Water Assessment Tool (Arc SWAT). The semi-automated Sequential Uncertainty Fitting (SUFI2) calibration process built in SWAT calibration and uncertainty program (SWAT-CUP) was used to calibrate and validate the model parameters using time series of monthly flow and sediment load data from 1996 to 2001 and validated with the observed data from 2002 to 2005. The most sensitive parameters were identified for the stream flow and sediment yield of the study area and used for model calibration and validation. The coefficient of determination (R2) and NSE values for the monthly flow calibration using SUFI2 are 0.78 and 0.75 respectively for validation it was 0.74 and 0.72. For monthly sediment yield by using SUFI2 calibration technique the model evaluation coefficients R2 and NSE for calibration were computed as 0.70 and 0.69 respectively, for validation, it was 0.71 and 0.68 respectively. This paper presents Monthly flow and sediment yield simulations in the Meki river watershed under different Best Management Practice (BMP) scenarios. Applied Scenarios are Base scenario, Terracing, Contouring, and Strip cropping. The scenario results showed that applying terraces, contouring and introducing Strip cropping reduced sediment yields by 49.01%, 34.12% and 15.23% respectively on average. Therefore, practicing Terracing for Meki watershed should be developed and encouraged for efficient sediment yield reduction.
Keywords: Meki
