Spatial-Temporal Assessment of Water Balance in the Barugbug Irrigation Command Area

Abstract

Efficient irrigation management requires accurate information regarding the spatial and temporal dynamics of water availability and irrigation requirements. However, water balance assessments in many irrigation systems are still commonly conducted using aggregated approaches, which provide limited information on the spatial-temporal distribution of water shortages within an irrigation command area. To address this limitation, this study evaluated irrigation water requirements, water availability, and water balance condition in Barugbug Irrigation Command Area using spatial approach. Effective rainfall was estimated through spatial interpolation using the Inverse Distance Weighting method. The irrigation water requirement was estimated using the Penman-Monteith method combined with pixel-based calculations. Water availability was estimated using the 80% dependable discharge (Q80) derived from operational records from 2014 to 2024. The analysis showed that irrigation water requirements consistently increased during the land preparation period, particularly in March and October. The highest Q80 value was recorded in March at 22.30 m3/s, whereas the lowest value occurred in October at 0.22 m3/s. Water balance analysis showed that surplus conditions generally occurred during the wet season, whereas water deficits emerged from the second period of August to the second period of October.