Water and energy management in an automated irrigation district

Abstract

An important modernization process providing pressurized irrigation systems to the traditional surface irrigation districts has taken place in Spain over the last 20 years However, an adverse consequence of modernization is the important increase in the energy cost in the modernized irrigation districts, which is aggravated by the current high energy prices. The Almudévar irrigation district (AID), a traditional surface irrigation district, was transformed into a pressurized sprinkler irrigation system in late 2010. The irrigation network was equipped with a high-level telemetry and remote control system that reaches the hydraulic valves of the irrigated blocks into which the plots are divided. Therefore, the telemetry system enables the centralized management of the irrigation scheduling from the district office. The district is divided into four independent networks with their own reservoirs and electric pump stations. A comparison of the land structure, crop patterns and irrigation management between the modernized AID in 2011 and the pre-modernization AID in 2006-2008 was performed. The temporal evolution of the irrigation water and energy demands in the 2011 irrigation season was analyzed with the available telemetry data from 2011. An irrigation performance index (SIPI) of the monthly and seasonal frequencies was computed for the main crops of the AID. Most irrigation events were performed during the low electricity tariff periods (P6 electric tariff) due to the centralized irrigation scheduling. Meteorological constraints had a low incidence in irrigation scheduling. Generally, a slight decrease in total irrigation deliveries was observed before and after medium-to-large precipitation events, but no changes in irrigation deliveries was observed with increases in wind speed. The exploitation of telemetry data in the AID has been an important tool to optimize the contracted electricity power in each tariff period and in decreasing the electric bill of the AID. This type of telemetry data analysis, similar to the analysis performed in the modernized AID in 2011, could be used in other water use associations as an important decision-making tool to improve water and energy management and to control the irrigation cost.