Assessment of Water Costs in Semiarid Brazil

Abstract

In semiarid regions, water supply infrastructure costs must be computed as precisely as possible, once society and the vulnerability of the ecosystem strongly depend on water availability. Water management federal and state laws also consider bulk water tariff an important management instrument especially where conflicts already exist. Therefore, in order to foresee public and private costs for water infrastructure for the coming years, unit water costs must be assessed. This research has provided two different types of water costs: investment (capital) costs as well as operational, maintenance and administration (O&M) costs. Different water supply possibilities were investigated: surface water supply by means of dams; groundwater in both crystalline and sedimentary basins; water reuse from stabilization ponds; rain water tanks; and water delivered by trucks (a rather common water source not only in dry years in rural communities of the Brazilian Semiarid). An important part of the investigation is the assessment of water demand management costs by means of improvements in irrigation technology. Indeed, irrigation demands ab out 70% of the bulk water in the state, and its technological level is still not good enough, so water managers can definitely decide to subsidize technological improvement in irrigation systems and, therefore, save water.