Analisis Penggunaan Lahan Tahun 2013 terhadap Ketersediaan Air di Sub Daerah Aliran Sungai Blongkeng

Abstract

Farmland drought that hit some areas at Blongkeng Sub Watershed in 2013 affect of the water balance. Potential of water supply at non-domestic land use is affected by the water needs in each landuse patterns. Decreasing of land for uptake and catchment rainfall is one of the factors that affect water balance system. The purpose of this research 1) Estimated availability of water at Blongkeng Sub Watershed, 2) Estimated the water needs based on the pattern of land use in 2013 at Blongkeng Sub Watershed, and 3) Analyze the water balance by months of wet and dry season preformance scope of Sub Watershed assessment. The research method using Thronthwaite Matter water balance, data sources of hidrometereologi such as rainfall and temperature from 3 stations around Blongkeng Sub Watershed for 10 years (2004-2013). Water needs from pattern of land use obtained through data processing based Remote Sensing and Geographic Information System. Landsat 8 recording June 2013 is processed into maps of land use in 2013 Blongkeng Sub Watershed, conducted a survey with purposive sampling method. Size of each land use can be known from the calculation of water needs. The potential of water availability is a comparison between amount of water available requirements. Results of this research is 1) Estimated availability of water in the wet season (November-April) has the highest surplus value in February is 193 mm, meanwhile for the dry season (May-October) has the highest deficit value in August is 184 mm. June to September can be predicted prone to drought, because it has an average deficit >

-160 mm/year at South Dukun and South Muntilan, 2) The highest water requirements of rice field

has a range from 4.5 to 12 million m 3 /year with has an average of 825 thousand m /year, while the lowest open land with an average of 100 m 3 /year, 3) Surplus water in the wet season are forest land at North-Central Dukun, plantation mix at West Srumbung, and field area at Srumbung, they had potential availability of water 796, 85 to 5644,01 m 3 /year. Land use where have deficit of water in the dry season is settlement, rice field and moor/field at South Dukun and Muntilan with potential availability of water <141.94 m 3 /year.