| Abstract： |
Continuous Contour Trench (CCT) is usually used in semi-arid watersheds to conserve water and reduce soil erosion. There is still a lack of understanding of how the CCT influences hydrological processes at a watershed scale. Therefore, CCT is used with arbitrary dimensions. However, standardisation of CCT dimensions may improve its performance from the user perspective. Therefore, this study investigated the mechanism of standardised CCT in influencing hydrological behaviour in two paired semi-arid micro-watersheds (treated with the CCT system versus untreated) by using a physically-based distributed hydrological modelling system MIKE SHE. The physically-based model performed satisfactorily in simulating surface runoff, groundwater levels and soil moisture during both calibration and validation periods. Subsequently, a stand-alone software, namely CCT_designer, was developed to make the standardisation technique user friendly. The CCT system was found to be useful in soil and water conservation in the treated micro-watershed, leading to considerably higher groundwater recharge and evapotranspiration (ET) than in the untreated micro-watershed. The MIKE SHE simulations showed that the CCT system resulted in 87.6 % average reduction in surface runoff, 42.4 % average increase in groundwater recharge, and 27 % average increase in the plant ET in comparison to the untreated micro-watershed. Using CCT_designer, the CCT depths for Ber, Custard apple and Anola are estimated as 0.27, 0.21 and 0.25 m, respectively, which showed a considerable reduction in the arbitrarily selected value of 0.30 m. Thus, CCT_designer may be a useful tool for soil and water management. |
