Potential water demand from the agricultural sector in hydrographic sub-basins in the southeast of the state of São Paulo-Brazil

Abstract

In Brazil, water management in agriculture is an extremely important issue in terms of water security, as well as in other regions of the world. Thus, the study presents a method to measure the potential water demand in the agricultural sector in two pairs (Pair 1 and Pair 2) of hydrographic sub-basins (SB) inserted in the Piracicaba River basin, located in southeastern Brazil. The methods adopted consisted of: using orbital sensor data to identify the types of temporary and permanent crops in the studied areas; preparing the Normalized Difference Vegetation Index to classify temporary crops, in four levels, which represent their development stages; collecting the irrigation need for each permanent and temporary crop through the “Technical Coefficients for Irrigated Agriculture” platform under the control of the National Water Agency; and, calculating the daily Potential Water Demand in the agricultural sector. The potential water demand showed differences between the pairs of the hydrographic sub-basins, due to the extension and the type of the predominant cultures. It is noteworthy that the Córrego dos Coqueiros hydrographic sub-basin is an area where the water supply may be compromised, due to the use of water resources in several sectors, in addition to agriculture. The need for crop irrigation, obtained through the National Water Agency platform associated with the geoprocessing of satellite images, made it possible to measure the daily potential water demand on the hydrographic sub-basin scale, which can assist in the assessment of the hydrographic region and the formulation of measures aimed at the sustainable use of water resources.