PENDEKATAN GEOMORFOLOGI UNTUK ANALISIS KERENTANAN KEKERINGAN DI DAERAH ISTIMEWA YOGYAKARTA

Arum Puspitorukmi, Prof. Dr.rer.nat. Junun Sartohadi, M.Sc.

2014 | Tesis | S2 Ilmu Lingkungan

Meteorological drought analysis, basing onprecipitation and evapotranspiration, is influenced by the condition of a landform unit. Each landform unit is also used as a unit in assessing the domestic water requirement. This study aimed to assess drought in terms of geomorphological and meteorological aspects as well as water requirement and to comprehensively analyze geomorphological drought based on the landform units. Rainfall areas were determined using isohyet, while evapotranspiration was obtained from water balance based on monthly precipitaion and temperature. In accordance with the Indonesian National Standard (Standar Nasional Indonesia – SNI) 2002, domestic water requirement was calculated based on the multiplication of water requirement per day per capita by total population. The population of each landform unit was interviewed in order to obtain more actual information.Furthermore, geomorphological analysis was conducted based on the relief/topography, composing materials, and geomorphological processes on each landform unit using stratified random sampling. The results show that the highest drought vulnerability is found in structural, solutional, and denudational landforms. High rainfall intensity in Sleman and northern part of Kulonprogo makes these areas not vulnerable to drought. The higher the evapotranspiration, the more vulnerable an area to drought. Most of the area in the DIY is moderately vulnerable to drought (Ia = 16.7-33.3). The highest domestic water requirement in the study area is in volcanic landform, i.e. 163.291.985 liter/day or 48,13 % of total domestic water requirement in the DIY. Comprehensive analysis on geomorphological drought resulted in a highly vulnerable area of 2,054.38 km 2 or 64.49 % of the DIY. In conclusion, the geomorphological condition of each landform unit plays a dominant role in drought vulnerability assessment in the DIY.

Meteorological drought analysis, basing onprecipitation and evapotranspiration, is influenced by the condition of a landform unit. Each landform unit is also used as a unit in assessing the domestic water requirement. This study aimed to assess drought in terms of geomorphological and meteorological aspects as well as water requirement and to comprehensively analyze geomorphological drought based on the landform units. Rainfall areas were determined using isohyet, while evapotranspiration was obtained from water balance based on monthly precipitaion and temperature. In accordance with the Indonesian National Standard (Standar Nasional Indonesia – SNI) 2002, domestic water requirement was calculated based on the multiplication of water requirement per day per capita by total population. The population of each landform unit was interviewed in order to obtain more actual information.Furthermore, geomorphological analysis was conducted based on the relief/topography, composing materials, and geomorphological processes on each landform unit using stratified random sampling. The results show that the highest drought vulnerability is found in structural, solutional, and denudational landforms. High rainfall intensity in Sleman and northern part of Kulonprogo makes these areas not vulnerable to drought. The higher the evapotranspiration, the more vulnerable an area to drought. Most of the area in the DIY is moderately vulnerable to drought (Ia = 16.7-33.3). The highest domestic water requirement in the study area is in volcanic landform, i.e. 163.291.985 liter/day or 48,13 % of total domestic water requirement in the DIY. Comprehensive analysis on geomorphological drought resulted in a highly vulnerable area of 2,054.38 km 2 or 64.49 % of the DIY. In conclusion, the geomorphological condition of each landform unit plays a dominant role in drought vulnerability assessment in the DIY.

Kata Kunci : Pendekatan Geomorfologis, Kebutuhan Air Domestik, Kerentanan Kekeringan.