Condition and Performance Assessment of Irrigation Infrastructure at Agri-Parks in Gauteng Province, South Africa

Abstract

South African agriculture accounts for 62% of the national water demand. Almost 45% of the water is wasted. Therefore, irrigation systems need to improve their water-use efficiency (WUE). However, the WUE of smallholder irrigation schemes in the country, including Agri-Parks, is not precisely known. A study was performed at four Agri-Parks (Rooiwal, Soshanguve, Tarlton, and Westonaria) in Gauteng province to assess the condition and performance of the irrigation systems, as part of a project that aimed to develop a WUE model for smallholder irrigation systems. The Agri-Parks were equipped with efficient irrigation systems in forms of drip and microjets. The assessments were performed at the system component level in February–March 2021. A Condition Assessment Model (CAM), developed by ARC-NRE/AE, was used for the condition assessment. Enumerators observed the system components visually and assigned conditions, which they uploaded into the model to generate condition indices (CIs). Water conveyance efficiency (CE) and distribution uniformity (DU) were assessed on delivery and infield systems, respectively. The CI values ranged 4–6, implying significant deterioration had occurred. The CE was 61–78%, while the DU was 60–95%. The infield system CI correlated positively with the DU, suggesting the CI could predict the DU in drip systems, which was encouraging for the proposed WUE model. However, further research covering a longer period and more Agri-Parks is recommended.