Water Asset Management International 4.1 (2008) 19-24

Strategies for integrating alternative groundwater sources into the water supply system of the Algarve, Portugal

TY Stigter, JP Monteiro and LM Nunes

FCMA - Universidade do Algarve, Faro, Portugal

J Vieira and MC Cunha

Departamento de Engenharia Civil, Polo II - Universidade de Coimbra, Coimbra, Portugal

L Ribeiro

CVRM/Geo-Systems Centre - Instituto Superior Tecnico, Lisboa, Portugal

H Lucas

Aguas do Algarve, Faro, Portugal

The future availability of drinking water in the Portuguese Algarve region is put at risk by the continuing rise in water demand, the decreasing amount of rainfall and the increasing potential for the occurrence of more-intense or longer-lasting drought periods, related to global climate changes. Moreover, tourism and agriculture, the two main economic activities in the region, rely heavily on the available water resources, particularly during dry periods, posing a threat to the public water supply. Until recently, the multimunicipal public water supply system (MPWSS), created in 2000 and managed by the regional Water Utility Águas do Algarve, was entirely based on surface water provided by large reservoirs. During the extreme drought of 2005, serious consequences of this single-source strategy were felt, when several reservoirs reached their exploration limit, and could not satisfy the water demand. During that period, the regional water utility realized that in order to guarantee public water supply in the long-term, a strategy based on an integrated water resources management (IWRM) scheme is needed. Therefore, alternative water sources need to be integrated into the MPWSS, the most important one of which is groundwater, the principal source of public supply in the Algarve before the existence of the MPWSS. Currently, a decision-aid model that will promote the IWRM in the region is being developed. In this paper In this paper, T.Y. Stigter, J.P. Monteiro, L.M. Nunes, J. Vieira, M.C. Cunha, L. Ribeiro and H. Lucas highlight one of the necessary tasks for that model, namely a screening selection of groundwater wells with sufficient quantity and quality to allow their integration into the water supply network. The quantitative criteria are based on aquifer properties and well yields.The results indicate that over 40 existing municipal wells, with a total yield of more than 1000 l/s, can be integrated into the MPWSS. An additional 25 wells (600 l/s) will be usable after appropriate disinfection and iron and manganese removal, or mixing with surface water.

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