WATER SUPPLY AND DEMAND ANALYSIS FOR RICE AND ORANGE CROPS IN DANDA BESAR SWAMP IRRIGATION AREA

The Danda Besar Swamp Irrigation Area is situated in Danda Jaya Village, Rantau Badauh District, Barito Kuala Regency, South Kalimantan Province, Indonesia. It covers a land area of 2200 hectares. The productivity of this irrigation scheme is significantly poor, with a yearly rice production of about 2 tons per hectare. Furthermore, Danda Jaya Village is renowned for being a prominent hub for oranges in South Kalimantan. This study aims to analyze the water balance condition in the Danda Besar Swamp Irrigation Area. The climatological data that were used in this study were obtained from the Syamsudin Noor Meteorological Station. The calculation of evapotranspiration uses the Penman-Monteith Method, whereas water availability is determined using the F.J. Mock Method without calibration. The computation of water demand is derived from the Indonesian Irrigation Regulation Standard. Result of this research are water availability in first January reached its peak at 2.31 m3/s, while in First half of September, it dropped to its lowest point at 0.06 m3/s. The peak of water demand was recorded in November I, reaching 8.23 m3/s, while the lowest demand was seen in March I, with 0 m3/s. The deficit periods occur from January I to February I, and subsequently from May I to December II. The surplus period occurs from February II to April II.