Irrigation evaluation and simulation at the Irrigation District V of Bardenas (Spain)

The surface Irrigated District V of the Bardenas Canal (Zaragoza, Spain) was evaluated, and alternatives were assessed to improve on-farm irrigation performance. Field work consisted of a soil survey and a campaign of irrigation evaluation. The results of the irrigation evaluations were extrapolated to the whole district using a hydrodynamic surface irrigation model. An average irrigation discharge of 152 L s^-1 results in a relatively low irrigation time (2.8 h ha^-1). Shallow soils, a limited conveyance network, and poor irrigation management practices determine that the application efficiency in the district is low, with an average of 49%. The district wide irrigation efficiency only reaches reasonable values when the system operates under water scarcity (49% in 2000 versus 66% in 2001). The simulation of surface irrigation indicated that the optimum irrigation time in the current situation is 1.7 h ha^-1. The optimization of the irrigation time would lead to an average application efficiency of 76%. Improved irrigation management can therefore result in substantial water conservation in the district.