MODELLING OF WATER BALANCE AND GROUNDWATER TABLE IN PEATLAND HYDROLOGICAL SUB UNIT 5 AND 6 KAHAYAN SEBANGAU, CENTRAL KALIMANTAN PROVINCE

• Main Author: Aliyatul Humam, Ivan
• Format: Theses
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/42005
• Institution: Institut Teknologi Bandung

Water balance in peatlands is a comparison between water availability and demand. Groundwater level fluctuations have a high correlation to the water balance that occurs on peatlands. Modeling was carried out for 20 years using infiltration and evapotranspiration data input, using Freewat / Modflow software. The groundwater table must not be less than minus 0.4 meters based on the decision of the Ministry of Environment (KLHK) No. 16 of 2017. Land modeling is conducted with a distance of 300 meters. Water availability is modeled for 20 years. Each canal blocking alternative has its own reliability to achieve minimum groundwater table requirements with no less than -0.4. Canal blocking 0.2 reliability 78.75%, blocking 0.3 reliability 85.42%, blocking 0.4 reliability 95.83% and blocking 0.5 reliability 100%. selected effectiveness is 0.5 meter canal blocking. the volume of water needed is 200,000 m3, to maintain a groundwater table in a 300 x 1000 land. Thus to raise a 0.5 meter groundwater table requires 0.6 meters of water per unit area per year. With the construction of canal blocking there is a long storage which increases water availability: for canal blocking 0.2 around 137,000 m3, blocking 0.3 is 164,000 m3, blocking 0.4 meters is 184,000 m3 and blocking 0.5 meters is 211,000 m3. Water needs are modeled for 20 years. With the construction of canal blocking there was an increase in water demand: for canal blocking 0.2 was 90,000 m3, blocking 0.3 was 130,000 m3, blocking 0.4 meters was 170,000 m3 and blocking 0.5 meters was 200,000 m3. Water balance is modeled for 20 years. With the construction of canal blocking there is a surplus in all scenarios, assuming the excess volume of water in the rainy season can all be accommodated in the planned storage pond. Water balance or excess water value: for canal blocking 0.2 is 47,000 m3, blocking 0.3 is 37,000 m3, blocking 0.4 meters is 14,000 m3 and blocking 0.5 meters is 11,000 km3.