Alluvial aquifer indicators for small-scale irrigation in northeast Brazil

Abstract The Brazilian Northeast is a semiarid area beset by drought and rural poverty. Irrigated agriculture exploits groundwater in the shallow alluvial aquifers in the base of the ribbon valleys. Uncontrolled exploitation and over irrigation are leading to soil salinisation and to degradation of the groundwater. Efforts have been made to promote efficient irrigation methods and to involve the farmers to reduce wastage. However, farm level water resource assessments are not yet undertaken to complement this activity. Farm and community level approaches to monitor and interpret groundwater level and salinity have been proposed. Interpretation has required physical studies to be undertaken in three typical groundwater systems in the region. The studies identify important links between hillslope runoff, groundwater use, subsurface controls and the annual and longer-term variations in water availability and water quality that have important impacts on sustainable groundwater use. Community level management is seen to be essential for sustainability.