The water balance analysis of several land uses in Tinalah sub-watershed, Kulon Progo

Tinalah sub-watershed has vulnerable to the threat of erosion and landslides. Erosion in the upstream watershed can trigger catastrophic flooding in the area below it. In addition, the problems that occur every year in the Tinalah sub-watershed are drought during the dry season and flooding during the rainy season. The water balance was analyzed by using Thornthwaite and Matter. The result shows that the dry index increased from June and the highest is in August. The highest runoff is in June (0.93). Mostly the land uses have deficit water during 4 months that are June to September, except the mixed planting has 3 months of deficit, whereas the area of the settlement has a longer deficit until 5 months. The simulation of land use in an agroforestry system shows the decreasing value of the deficit which then it will affect the value of the Drought Index (Ia) which also decreases. © Published under licence by IOP Publishing Ltd.