The Imperial Irrigation Decision Support System - Evolution from Project Planning to Operations

The Imperial Irrigation Decision Support System (IIDSS) is a comprehensive tool for evaluating structural and operational modifications to the Imperial Irrigation District's delivery and drainage systems. The IIDSS toolkit contains several modules including the MODSIM hydrologic model. IIDSS was originally developed as an analysis tool for use in preparation of the environmental documentation for the water transfer between the Imperial Irrigation District and the San Diego County Water Authority. Specifically, the model was used to investigate how various scenarios for meeting the water conservation requirements of the transfer would affect flows and water quality throughout the District's irrigation and drainage system and impact discharges to the Salton Sea. Now that the transfer is in the process of being implemented, the IIDSS is evolving from a planning tool to an operational aid. This paper begins with background on IID and on the water transfer agreement. The paper then discusses the original formulation of the IIDSS and how the system is being modified to improve its functionality as a planning and operational tool.