Optimizing micro watershed management for soil erosion control under various slope gradient and vegetation cover conditions using SWAT modeling

Abstract

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.

Calibration of a modelling approach for sediment yield in a wattle plantation, KwaZulu-Natal, South Africa

“…Due to its strong sediment yield component, SWAT could be used to extrapolate sediment distribution throughout the catchment, identify vulnerable areas and promote best management practices. As such, it is considered a more suitable tool for agricultural management practices in watersheds of varying sizes, compared with other models (Nabi et al, 2017).…”

Vulnerabilidade Ambiental no Município de São Domingos – Go

“…No caso da vulnerabilidade natural à perda de solos, há diversas propostas metodológicas conhecidas, sendo uma das mais difundidas a Equação Universal da Perda de Solos, ou simplesmente USLE (Wischmeier;Smith, 1978;Alewell, 2019), como é conhecida na sigla em inglês. Como o próprio nome diz, ela se propõe a estimar a perda média de solos pela erosão em vertentes, consistindo em um modelo empírico de estimativa da erosão laminar (Nabi et al, 2017;. A USLE também tem sido utilizada em trabalhos que se propõem a mapear a vulnerabilidade ambiental, a exemplo de Ribeiro et al (2016) e Souza et al (2019).…”

Modelling soil erosion response to sustainable landscape management scenarios in the Mo River Basin (Togo, West Africa)

“…On the other angle, steep slopes (N 15°) showed high prevalence of soil loss. Similarly, Nabi et al (2017) suggested that soil and water conservation measures targeting steep slopes significantly reduce soil loss at watershed level. This implies that comprehensive soil conservation measures should be developed to control erosion on steep slopes and prevent sediment delivery to rivers (Haiyan and Liying, 2017;Gashaw et al, 2017).…”