Analysis of factors affecting the intake gate operations of Gerokgak Reservoir for command areas of Subak Gede

Abstract

Subak Gede in Gerokgak Village, Buleleng, practices traditional irrigation in Bali based on Tri Hita Karana principles. Subak sources water from Gerokgak Reservoir, where intake gate operations depend on three factors: the recent ten-day discharge (item 1), rainfall in command areas (item 2), and crop type (item 3). Quantification Analysis I simulated the intake gate from 2019 to 2022, comprising Models A to D, each using yearly data for its respective year (2019, 2020, 2021, 2022), and Model E using four years of data. Items 1 and 2 had high, moderate, and low categories; item 3 had paddy, palawija, paddy-palawija, and fallow categories. The simulation exhibited strong correlations between predicted and recorded discharge of every quantification model, with R-total > 0.6, varying for each sample year. Based on the analysis, the three items showed a different impact every year, depending on the item-category distribution and variation. Notably, due to its sample, quantification Model E excelled in predicting intake gate operations for other yearly data, including its own sample year.