EVALUATION OF IRRIGATION WATER AVAILABILITY (Case Study Yeh Ho Watershed, Tabanan, Bali)

• Main Author: PUTU NANDA DEWI RAMADHANI - NIM: 12814019 , NI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/29674
• Institution: Institut Teknologi Bandung

<p align="justify">Bali is a world tourism destination with one of its supports is the agricultural sector which is managed by the Subak system and recognized by UNESCO as a world cultural heritage. The biggest subak in Bali is known as Subak Jatiluwih in Tabanan, where the irrigation system is sourced from the Yeh Ho watershed. This region is also the largest rice barn on the island of Bali. The performance of this Subak is very dependent on the availability of water, but in the last 15 years there has been a decline in rice production and the worst crop failure in 2015 due to a prolonged dry season. This indicates a disturbance in water balance during the growth period of rice plants in a certain season. <br /> <br /> <br /> <br /> <br /> Subak as Balinese local wisdom should be preserved, one of which is by evaluating the availability of water sources which are the main support for its sustainability. The evaluation method is carried out by paying attention to various aspects, including: climate characteristics, climate variability, climate suitability and land for rice commodities, and the frequency of regional drought. The dependable discharge calculation method is used to compare the needs with the availability of irrigation water. This method uses a reliability value of 80% as an estimate of the availability of irrigation water. <br /> <br /> <br /> <br /> <br /> Yeh Ho watershed in the period 1992-2016 has a B2-C3 climate type according to Oldeman, which means it is suitable for planting 1-2 times a year without irrigation assistance. Based on climate and land suitability, there are 32.432 ha area with S2 suitability class (quite appropriate) and 9.426 ha S1 (very suitable) for planting rice. The results of the comparison between availability and needs of irrigation water indicate the occurrence of water surplus during the first planting period, and water deficit during the second planting period when the consumptive period of the crop. The water deficit during the dry season is related to drought on a 12-month time scale. In addition, the diversity of water availability from season to season is generally influenced by rainfall where the quantity is dominated by monsoonal circulation, as well as other minor influences such as convection activities. <p align="justify"> <br />