Portuguese irrigation canals: lining solutions, anomalies and reabilitation

Abstract

Irrigation canals are primary hydraulic infrastructures from an agricultural point of view and their performance is highly dependent on the efficiency and durability of their coatings. This paper presents the main conclusions of a survey undertaken in Portugal which concluded that in most situations the following technologies are used: concrete cast on site; precast concrete slabs; prefabricated membranes (polymer bitumen or synthetic). These linings may manifest various pathologies with significant consequences on the amount of water lost due to lack of watertightness. These defects are classified by lining solution and their main causes identified. Finally, an exhaustive set of recommendations and rehabilitation techniques are described in order to minimize water leakage from the canals.