## 2 Materials and Methods
### Area Study
The Floresta municipality was chosen because it was the closest station to sub-basin 73 under study, and so the model would be better calibrated and adjusted for this area. Because of this, here, we validated the SUPer data with observed data. To evaluate the calibration of the model, the determination coefficient was used. Soils: data spatial characteristics of soil characteristics were obtained through two databases: (i) the spatial mapping of soils came from the Agroecological Zoning of the State of Pernambuco (ZAPE). These data are available in the form of a map with a scale of 1:250,000 on the website [[http://www.uep.cnps.embrapa.br/zape](http://www.uep.cnps.embrapa.br/zape)]([http://www.uep.cnps.embrapa.br/zape](http://www.uep.cnps.embrapa.br/zape)) accessed on 12 May 2023, and (ii) the data relating to the physical-chemical measurements of each type of soil were from the EMBRAPA Soils database ([[https://www.bdsolos.cnptia.embrapa.br/consula_publica.html](https://www.bdsolos.cnptia.embrapa.br/consula_publica.html)]([https://www.bdsolos.cnptia.embrapa.br/consula_publica.html](https://www.bdsolos.cnptia.embrapa.br/consula_publica.html)) accessed on 12 May 2023). Land use and cover: initial usage and coverage data were obtained through Landsat TM 5, ETM+/Landsat 7 and OLI/Landsat 8 with the 1975-2013 series available at [[https://earthexplorer.usgs.gov/](https://earthexplorer.usgs.gov/)]([https://earthexplorer.usgs.gov/](https://earthexplorer.usgs.gov/)) accessed on 12 May 2023 and www.dgi.inpe.br/CDSR/ accessed on 12 May 2023. The products were downloaded based on radiometric quality and the absence of cloud cover (<10%), and created eight annual land cover maps (1975, 1993, 2001, 2003, 2005, 2007, 2009 and 2013) using 42 images and the available GDAL (Geospatial Data Abstraction Library) at [[http://www.gdal.org/](http://www.gdal.org/)]([http://www.gdal.org/](http://www.gdal.org/)) accessed on 12 May 2023. At this stage, all data were formatted for input into the SWAT model, and the project was created with the help of the ArcSWAT tool available for ArcGIS software in [[http://swat.tamu.edu/software/arcswat/](http://swat.tamu.edu/software/arcswat/)]([http://swat.tamu.edu/software/arcswat/](http://swat.tamu.edu/software/arcswat/)) accessed on 12 May 2023. The usage maps were processed using the tool SWAT2009_LUC_64 bit.exe, which is a preprocessor that implements the land cover dynamics in SWAT. Details about the software can be obtained from. Each project corresponds to a single basin. ArcSWAT has been configured to delimit sub-basins or drainage areas of approx. 10,000 hectares, generating sub-basins and HRUs (HydrologicalResponse Units); Range Brush was the vegetation type available in the SWAT database and chosen to represent the Caatinga, due to its proximity in terms of physical characteristics. Initially, the data available in the database regarding the Range Brush were not modified, except for the vegetation class that was modified for the warm season annual legume to avoid the dormancy of the vegetable vegetation. It was used for five years for the warm-up of the model. For this year's warming, SWAT simulated climate data using the weather tool generator.