Towards sustainable irrigation: Identifying leaks to reduce reservoir water losses

Abstract

Irrigated agriculture has played a key role in increasing agricultural productivity and supporting the expansion of Brazil’s agribusiness sector. Over the past decade, the combined use of center pivot irrigation systems and reservoirs lined with HDPE geomembranes has grown significantly. In this context, geomembranes act as hydraulic barrier systems intended to minimize water losses. However, the use of geosynthetics does not guarantee the complete absence of leaks, nor does it fully eliminate the risk of water losses or structural failures. In this study, an Electrical Leak Location (ELL) survey was performed to evaluate the integrity of a 1.0 mm HDPE geomembrane installed in a 6.4 ha irrigation reservoir that had been in operation for two years. At the time of inspection, the reservoir presented a maximum water depth of approximately 2.5 m in the deeper area and 0.5 m in the shallower area. The survey identified 91 defects within approximately 3.34 ha of submerged geomembrane, corresponding to 27 leaks/ha. The most frequent defect types were knife cuts, extrusion weld failures, and punctures. Most of the identified defects were associated with installation-related deficiencies attributable to Construction Quality Control (CQC) failures, which are conventionally identified through Construction Quality Assurance (CQA) programs.