Groundwater resources for agricultural purposes in the Brazilian semi-arid region¹

Recursos hídricos subterrâneos para fins agropecuários no semiárido brasileiro

HIGHLIGHTS:

Groundwater reserves are not sufficient to meet demand and water use efficiency must be im-proved.

Overexploitation of groundwater prevents aquifer recovery and agricultural activities.

Groundwater quality is not limiting for agricultural use; however, water resources management strategies are required.

ABSTRACT

Exploitation of groundwater resources with no proper characterization of water reserves jeopardizes the quantity and quality of water available in the future. A major challenge is finding appropriate methods or coefficients to evaluate the carrying capacity of the aquifer. The objective of this study was to quantitatively and qualitatively characterize water reserves to provide information and management strategies for the rational use of available water resources in an alluvial aquifer in the Brazilian Northeastern semi-arid region. Shallow and medium-depth wells were analyzed. Water tables were monitored in the dry and wet seasons to calculate water reserves. Groundwater samples were collected for the determination of water quality for irrigation purposes. The increase in agricultural activities is jeopardizing the sustainability of the aquifer’s water, as reserves are not sufficient to meet this demand. Groundwater quality is not limiting for agricultural use. Converting surface irrigation into localized methods will potentially increase water productivity and consequently the irrigated area. This study provides data and makes it possible to recommend appropriate strategies for the exploitation of groundwater resources for the maintenance of agricultural activities under semi-arid conditions, and to avoid overexploitation.

Key words:
aquifer overexploitation; need for irrigation; water quality