A major objective of irrigation water delivery system designs is to provide capacity for good water control. Water control is defined as the regulation of flow for adequate and equitable delivery to the farms served by the system. To design for water control the design of hydraulic structures must be well integrated with prescribed water delivery schedules. The performance parameter, control capacity (CC), was introduced as a measure of the capacity of a system to deliver water according to schedule. A spatially varied flow model was used as a design tool to predict the expected average and relative variability of CC for alternative hydraulic structure designs and water delivery schedules. A simple application demonstrated the utility of CC in evaluating potential system performance and showed the importance of considering the interaction between structural features and delivery schedules in making design decisions.
