Abstract

SCOTT-SHAW, BC; HILL, TR  and  GILLHAM, JS. Calibration of a modelling approach for sediment yield in a wattle plantation, KwaZulu-Natal, South Africa. Water SA [online]. 2020, vol.46, n.2, pp.171-181. ISSN 1816-7950.  http://dx.doi.org/10.17159/wsa/2020.v46.i2.8232.

Hydrological modelling is an appropriate approach to investigate the effect of interactions of climate, land-use and soil on the water-use of natural or managed ecosystems, in particular where spatial heterogeneity exists. The Soil and Water Assessment Tool (SWAT) model has evolved into one of the most widely used catchment-scale hydrological models, which has been extensively used to better understand hydrological processes. In this paper, the SWAT model was adopted to simulate a wattle plantation in KwaZulu-Natal, South Africa. User-defined vegetation growth, soil and management input parameters were constructed for the study area based on site measurements. These parameters were subsequently modified using the Sequential Uncertainty Fitting (SUFI-2) analysis routine to calibrate the model. The calibrated model captured seasonal trends in the observed sediment and streamflow data. The compilation of spatially explicit sediment output provides a useful approach to manage catchments by identifying high erosion-risk areas. The SWAT model, using site-specific input parameters, provides a platform for subsequent hydrological and sediment modelling in South Africa.

Keywords : commercial plantations; modelling; sediment yield; surface run-off; SWAT.

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