ABSTRACT
By and large, the climate of the region can be termed as semi-tropical and humid. The Progo River has the highest run-off among all regional rivers. Rivers of the region transport an important volume of sediments. Groundwater in the region can be generally found at less than 10 m below the ground surface in the central plain. Construction materials are abundant in the region. Most hamlets of the central lowlands own at least one kiln where bricks and roof tiles can be locally produced. Though receiving a relatively important amount of precipitation, the uplands located south of the District of Gunung Kidul have soils which do not retain rainfall, while the groundwater lies very deep. The largest groundwater aquifers are found in the geological formation of Sleman and Yogyakarta, administratively located in Sleman District. In Gunung Kidul District, some fair agricultural land is located north of the Oyo River where irrigation is provided in some areas.
