Kajian agihan airtanah bebas di sub das Kenatan Kabupaten Sragen

Rio Adhi Prastoro, Prof. Dr. Dulbahri; Drs. Nurul Khakhim, M.Si.

2002 | Skripsi | S1 KARTOGRAFI DAN PENGINDERAAN JAUH

Penelitian yang dilakukan di Sub DAS Kenatan, Kabupaten Sragen ini merupakan terapan teknik penginderaan jauh khususnya menggunakan citra satelit Landsat TM tahun 1996 dan pemanfaatan Sistem Informasi Geografis untuk studi airtanah bebas. Tujuan dari penelitian adalah mengkaji kemampuan pemanfaatan penginderaan jauh dan Sistem Informasi Geografis dalam menginventarisasi parameter-parameter fisik wilayah yang berhubungan dengan keberadaan dan distribusi airtanah bebas. Metode yang digunakan dalam penelitian ini adaiah integrasi teknik penginderaan jauh dan Sistem infonnasi Geografis, dilengkapi dengan kerja lapangan dan analisis data sekunder. Penentuan sampel ditentukan dengan metode stratified sampling. Pemrosesan dan analisis data baik berupa data grafis maupun data atribut, menggunakan perangkat lunak Sistem Informasi Geogratis terutama ILWIS 2.2 dan Arc View 3.1. Hasil penelitian menunjukkan uji ketelitian interpretasi citra satelit dalam peneIitian ini adalah: untuk bentuklahan 89,4 %, jenis batuan 80,5 %, dan 91 % untuk penggunaan lahan. Agihan akifer bebas yang diidentifikasikan terbagi menjadi 4 kelas, yaitu: daerah airtanah langka yang meliputi luasan 13,72 akifer dengan produktivitas rendah permeabilitas sekunder 21,04 km2, akifer dengan produktivitas sedang permeabilitas sekunder 40,10 km2, dan akifer dengan produktivitas tinggi permeabilitas sekunder 103,32 km2. Agihan kemampuan infiltrasi terbagi menjadi 4 kelas, yaitu: kemampuan infiltrasi kecil yang mempunyai luasan 59,40 km2, kemampuan infiltrasi sedang 99,98 km2, kemampuan infiltrasi besar 12,4 km2, dan kemampuan infiltrasi sangat besar 6,54 km2. Agihan besaran masukan air daerah penelitian merupakan tumpangsusun informasi agihan akifer bebas dan agihan kemampuan infiltrasi yang terbagi menjadi 5 kelas, yaitu: besaran masukan air sangat kecil yang meliputi luasan 1,05 km2, besaran masukan kecil 2,64 km2, besaran masukan air sedang 140,35 km2, besaran masukan besar 33,82 km2, dan besaran masukan air sangat besar meliputi 0,46 km2. Akhirnya, berdasarkan besaran masukan air, besaran curah hujan, dan pengaruh penggunaan lahan terhadap perlakuan air hujan yang jatuh di atasnya, maka dapat ditentukan agihan airtanah bebas daerah penelitian. Agihan airtanah bebas terbagi menjadi 5 kelas, yaitu: agihan airtanah bebas berproduksi sangat kecil yan& mempunyai luasan 21,35 km2, agihan airtanah bebas berproduksi kecil 35,70 km2 agihan airtanah bebas berproduksi sedang 18,15 km2, agihan airtanah bebas herproduksi besar 70,98 km2, dan agihan airtanah bebas berproduksi sangat hesar seluas 32,14 km2. Hasil akhir yang diperoleh menunjukkan bahwa integrasi teknik penginderaan jauh dan Sistem Informasi Geografis dapat digunakan untuk melakukan pengidentifikasian kawasan airtanah bebas dengan tingkat produktivitasnya yang mendasarkan pada informasi parameter fisik lahan

The research which had been conducted at kenatan Watershed of Sragen District, is an apllication of remote sensing techniques especially by using Landsat TM satelite images which recorded at 1996 and Geographic Information System to study shallow groundwater. The aim of this research is to evaluate the capability of remote sensing techniques and Geographic Information System in order to take inventory of physically factors which have relationship with the existing and distribution of shallow groundwater. The methods which were used in this research are integration of remote sensing techniques and GIS, added with field works and secondary data analysis. The sample were takeri according to stratified sampling methods. GIS soft wares were used to process and analysis in both graphic and attribute datas, especially by using ILWIS 2.2 and Arc.View 3.1. The results of the research show that the test of confidences of satelite images interpretation are 89.4 % for landform, 80.5 % for lithology, and 91 % for land use. The distribution of shallow aquifers which had been identificated were devided into 4 classes and their wides, which are 13.72 km2 for rare groundwater zone, 21.04 km2 for aquifer with low productivity and secondary permeability, 40.1 km2 for aquifer with medium productivity and secondary permeability, and 103.32 km2 for aquifer with high productivity and secondary permeability. The distributions of infiltration capability were devided into 4 classes and their wides, which are 59.4 km2 for low infiltration capability, 99.98 km2 for medium infiltration capability, 12.4 km2 for high infiltration capability, and 6.54 km2 for very high infiltration capability. The distributions of water input magnitude were devided into 5 classes and their wides, which are 1.05 km2 for very low magnitude of water input distribution, 2.64 km2 for low magnitude of water input distribution, 140.35 km2 for medium magnitude of water input distribution, 33.82 km2 for high magnitude of water input distribution, and 0.46 km2 for very high magnitude of water input distribution. According to the distributions of water input magnitude, rain fali distributions, and the influence of landuse against to rain fall, the shallow groundwater distributions can be obtained. The shallow groundwater distributions were devided into 5 classes and their wides, which are 21.35 km2 for very low productivity of shallow groundwater, 35.7 km2 for low productivity of shallow groundwater, 18.15 km2 for medium productivity of shallow groundwater, 70.98 km2 for high productivity of shallow groundwater, and 32.14 km2 for very high productivity of shallow groundwater. Final results show that the integration of remote sensing techniques and GIS can be used to identificate the zones of shallow groundwater

Kata Kunci : Agihan airtanah bebas,Kenatan,Sragen,Jawa tengah