115-Development and Application of an Integrated Reservoir-Based Canal Irrigation Model (IRCIM).

Abstract

Most of the irrigation literatures mainly focus on the demand and distribution aspects only. Irrigation projects, which receive water from reservoir, can be challenging to manage since annual fluctuations in runoff from the reservoir's catchment can have considerable impact on the irrigation management strategy. Several independent models have already been developed for runoff prediction, reservoir operation, crop water demand calculation and canal flow simulation. However, these individual models may not meet the objectives of the irrigation departments dealing with the whole scheme, This paper presents the development and application of an Integrated Reservoir-based Canal Irrigation Model (IRCIM) which can take into account the impact of rainfall on reservoir inflow through catchment hydrologic modelling, the irrigation water availability through reservoir water balance, the irrigation demand through command hydrologic modelling, and decide on a rotational delivery schedule that minimizes the gap between demand and supply through proper canal irrigation management. Developed model was tested for Kangsabati Irrigation Project, West Bengal, India. Saturated hydraulic conductivity value (Ks) was determined as 4.31 mm crl for Kangsabati reservoir. A year-independent alternative delivery schedule: transplanting date as July 24, number of irrigation as 3 and type of rule curve as MRC (minimum rule curve), was also proposed which can be followed mechanically without manager's expertise. Thus, it was recommended to adopt the alternative delivery schedule which produced quite comparable performance with the existing delivery schedule for all the simulation years.