Analysis of soil water balance and availability on several land use types for hydrological disaster mitigation in Krueng Jreu Sub-watershed

The increasing intensity of land conversion in the Krueng Jreu sub-watershed from forest to non-forest or land-use changes causes changes in land biophysical characteristics. Changes in land biophysical characteristics may cause a change in soil water balance, availability, and increased levels of flood and drought vulnerabilities. The objectives of the study were focused on analyzing soil water balance and soil water availability on several land-use types and its linkages to hydrological disaster mitigation in the Krueng Jreu sub-watershed. Calculation of the soil water balance using Thornthwaite & Mather's methods and data during 20092018. The results showed that soil water availability (SWA) in research areas with a total area covered 23,218.06 hectares consist of 2 classes namely: fewer criteria (40.10 <= SWA <= 60.00) with a large area 15,948.70 ha (68.69%), and means criteria (20.10 <= SWA <= 40.00), with a large of area 7269.35 ha (31.31%). The highest actual evapotranspiration occurs in the primary forest, and the lowest is occur in the secondary forest. The total deficit of soil water availability in a year reaches 1,892.40 mm year(-1), and the total surplus was 2329.20 mm year(-1). The highest percentage of soil water availability was found in primary forests (67.20%) and the lowest in the shrubs (36.36%). Disaster mitigation should be prepared to anticipate floods in surplus rainwater during October-Mai (7months), and forest conflagrations during deficit rainwater from June-September (5 months).