## 2 Materials and Methods  
### Area Study  
The hydrographic basin under study has an area of 236.02 km\({}^{2}\). It is a sub-basin of the Pajeu hydrographic basin. This area is in the hinterland of Pernambuco with semi-arid weather conditions, Figure 1. It is located next to the Sao Francisco River and is under the impact of the transposition of the Sao Francisco River. Part of its basin covers indigenous areas, as seen in Figure 1B. The basin is located at UTM coordinates \(-8.526\) and \(-38.124\)the water balance rations in the basin study is streamflow/precip, which is 0.244; the baseflow/total flow is 0.545; the surface runoff/total flow is 0.455; the perc/precip is 0.163; and the ET/precipitation is 0.695. The land use in the basin is SPAS-summer pasture and CRWO-cropland/woodland mosaic. The geomorphology is shown in Figure 1C. Figure 1: Location of the hydrographic basin 73, in Pajeu. (**A**) Spatial localization, sub-basin 73. (**B**) Detail scale, sub-basin 73. (**C**) Geomorphology. In this study, 61 years of daily-scale data were utilized, covering the period from 2016 to 2021. These daily data are available within the model. Daily hydrological cycle data contribute to the effective management of water resources within a region. This encompasses the monitoring of water levels in rivers, lakes and aquifers, as well as the measurement of precipitation and evaporation rates [28]. Such information is indispensable for the planning and allocation of water resources for potable water supply and agricultural irrigation. To warm up the SWAT-Soil Water Assessment Tools model, five years were used. The SWAT model that was used for water balance modeling was the 2012 version [12]. The SWAT model (Soil and Water Assessment Tool, available free of charge at [[http://swat.tamu.edu](http://swat.tamu.edu)]([http://swat.tamu.edu](http://swat.tamu.edu)) accessed on 12 May 2023 has been gradually expanding its borders, as it has a profile of varied models for the interests of both private companies and public bodies. SWAT is a semi-distributed model in which a basin target river basin is divided into several sub-basins, which in turn are subdivided into hydrological response units (HRUs) that consist of areas homogeneous in relation to land use and cover, relief and soil characteristics. The HRUs are represented in the model as a percentage of the sub-basin. SWAT requires observed data on four essential components: relief, climate, soils, and land use and cover. Relief: spatial relief data were obtained using the data from EMBRAPA Relief ([[https://www.cnpm.embrapa.br/projects/relevobr/](https://www.cnpm.embrapa.br/projects/relevobr/)]([https://www.cnpm.embrapa.br/projects/relevobr/](https://www.cnpm.embrapa.br/projects/relevobr/)) accessed on 12 May 2023), which provide corrected products from the NASA SRTM (Shuttle radar topography) mission, which aims to map the topography of the Earth's surface. The data from this model are in image format, whose pixels have a spatial resolution of 90 m and altitude (m). Climate: the climate data of the series, i.e., precipitation, global radiation, humidity relative air temperature or dew point temperature, average air temperature, temperatures air maxima and minima, and wind speed, were obtained for the years spanning from 1961 to 2021 through the INMET database (National Institute of Meteorology; [[http://www.inmet.gov.br/projects/rede/pesquisa/inicio.php](http://www.inmet.gov.br/projects/rede/pesquisa/inicio.php)]([http://www.inmet.gov.br/projects/rede/pesquisa/inicio.php](http://www.inmet.gov.br/projects/rede/pesquisa/inicio.php)) accessed on 12 May 2023). Then, only the station of Floresta located in the state of Pernambuco was selected. We used average monthly values simulated and observed in Floresta with a longitude of -38.64 and latitude of -8.61. The station code is 48860000 to the runoff obtained by the Brazilian water agency.