Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/hess-2017-532
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
24 Oct 2017
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Hydrology and Earth System Sciences (HESS).
Optimizing micro watershed management for soil erosion control under various slope gradient and vegetation cover conditions using SWAT modeling
Ghulam Nabi1, Fiaz Hussain2, Ray-Shyan Wu3, Vinay Nangia4, Riffat Bibi5, and Abdul Majid6 1Centre of Excellence in Water Resources Engineering, University of Engineering and Technology, Lahore, Pakistan
2Department of Civil Engineering, National Central University, Taiwan. Lab Engineer, PMAS-Arid Agriculture University Rawalpindi, Pakistan
3Department of Civil Engineering, Water Resource Engineering Group, National Central University, Taiwan
4The International Centre for Agriculture Research in the Dry Areas (ICARDA)
5Soil and Water Conservation Research Institute (SAWCRI)
6The International Centre for Agriculture Research in the Dry Areas (ICARDA)
Abstract. This study evaluated parameters of soil erosion and optimization of micro watersheds by applying a semidistributed basin-scale Soil and Water Assessment Tool (SWAT) model in various small watersheds of the Chakwal and Attock districts of Pothwar, Pakistan. The model was calibrated and validated on a daily basis for a small catchment (Catchment-25) of the Dhrabi watershed without any soil conservation structures. Statistical measures (R2 and EN-S) were used to evaluate model performance; the model performed satisfactorily well for both surface runoff and sediment yield estimations, with the R2 and EN-S values both being greater than 0.75, during calibration (2009–2010) and validation (2011). The model was applied to various small watershed sites in the Chakwal and Attock districts after successful calibration and validation. Soil erosion estimation was performed at these sites having loose stone soil and water conservation structures and being under various slope gradient and vegetation cover conditions. The structures had significant effects, and the average sediment yield reduction engendered by the loose stone structures at the various sites varied from 54 to 98 %. The sediment yield and erosion reductions were also compared under conditions involving vegetation cover change. Agricultural land with winter wheat crops had a higher sediment yield level than did fallow land with crop residue, which facilitated sediment yield reduction along with the soil conservation structures. Analyzing various slope gradients revealed that all selected sites had a maximum slope area of less than 5 %; stone structures were installed at these sites to reduce sediment yield. Based on slope classification analysis, the model was upscaled for the whole districts of Chakwal and Attock. The results indicated that 60 % of Chakwal (4095 km2) and Attock (3918 km2) by area lies in a slope range of 0–4 %; this thus implies that considerable potential exists for implementing soil conservation measures by installing stone structures. Estimates revealed that minimum sediment yield reductions of 122,850 t year−1 in Chakwal District and 117,540 t year−1 in Attock District could be achieved by installing loose stone structures in 60 % of the agricultural areas of both districts having a slope of 0–4 %; these findings can serve as a reference for policymakers and planners. The overarching findings of this study show that the SWAT model provides reliable results for sediment yield and soil erosion estimation, which can be used in rocky mountainous watersheds for erosion control and watershed management.

Citation: Nabi, G., Hussain, F., Wu, R.-S., Nangia, V., Bibi, R., and Majid, A.: Optimizing micro watershed management for soil erosion control under various slope gradient and vegetation cover conditions using SWAT modeling, Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2017-532, in review, 2017.
Ghulam Nabi et al.
Ghulam Nabi et al.
Ghulam Nabi et al.

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