Figure 1: Geographical localization of the studied sites P1-P4,
delimited by colored lines in the four side images and reported as
rectangles in the central image, where the whole analyzed watershed is
also shown.
Data collection
For the realization of a complete SWAT model several datasets are
required as inputs data. The Digital Elevation Model (DEM), needed for
the delineation of the main watershed, river network, and sub-basin
generation, was provided by the Shuttle Radar Topography Mission (SRTM),
with a cell resolution of 10 x10 m. The land cover was obtained from the
Corine Land Cover database (CLC, 2018), while the soil classification
was extracted from Direcção-Geral de Agricultura e Desenvolvimento Rural
(DGADR, 2013) with a scale of 1:25,000 (12.5 x 12.5 m). The information
on soil characteristics, like saturated hydraulic conductivity (Ks),
available water content (AWC), and bulk density (BD) were defined with
the Harmonized World Soil database (FAO, 2012) a vectorial geodatabase
obtained from a 30” resolution map and further refined using 3,000 soil
columns from the World Soil Information Service (Batjes et al., 2017,
2020; Ribeiro et al., 2020) and literature data (Grilli et al., 2021),
while other missing soil’s parameters were obtained from SWAT’s default
dataset (Table S2). Data of streamflow and sediments load for the period
1985-1989 utilized to calibrate and validate the model were obtained
from four hydrometric stations located inside the watershed named
Albernoa, Monte da Ponte, Oeiras, and Entradas (Fig. 1) (SNIRH, 2006).