PENDEKATAN RESPON-DEBIT CURAH HUJAN UNTUK KARAKTERISASI AKUIFER KARST DI MATAAIR SUMBERSEWU, REMBANG

BAHAR PANDU DEWANTARA, Dr. Tjahyo Nugroho Adji, M.Sc.Tech

2019 | Skripsi | S1 GEOGRAFI LINGKUNGAN

ABSTRAK Sistem hidrologi karst memiliki karakter unik dengan adanya dominasi proses pelarutan menjadikan lebih berkembangnya sistem aliran bawah tanah dengan diferensiasi komponen aliran diffuse, fissure, dan conduit. Penelitian dilakukan bulan Januari 2016 hingga Januari 2017. Untuk mengetahui korelasi antara discharge dan recharge menggunakan metode cross correlation dan komparasi curah hujan dan debit. Metode kedua yaitu penentuan konstanta resesi hidrograf untuk mengetahui komponen aliran mataair dan tingkat perkembangan karst dibuat menggunakan Master Recession Curve (MRC). Hasil penelitian menunjukkan bahwa nilai konstanta resesi Mataair Sumbersewu didominasi oleh komponen aliran diffuse selama rentang waktu penelitian. Mataair Sumbersewu memiliki nilai korelasi (R) sebesar 0,0031 dan time lag rata rata adalah 14 jam. Rata rata nilai konstanta resesi aliran diffuse (0,9942), nilai konstanta aliran fissure (0,3575), dan tidak ditemukan aliran conduit. Perhitungan menggunakan MRC juga menunjukkan hal yang sama, yaitu tidak ditemukan aliran turbulent pada Mataair Sumbersewu dan durasi time lag rata rata adalah 14 jam.

Karst hydrological system has a unique character with the dominance of the dissolution process making it more developed underground systems with differentiation of diffuse, fissure and conduit flow components. The study was conducted from January 2016 to January 2017. To determine the correlation between discharge and recharge using the cross correlation method and comparison of factual rainfall and discharge data. The second method was determined the hydrograph recession constant to find out the components of the spring flow. Furthermore to find out the development level of karst, we used the Master Recession Curve (MRC). The results showed that the value of the recession component of the Sumbersewu Springs recession was dominated by diffuse flow components over the span of the study period. Sumbersewu Springs has a correlation value (R) of 0.0031 and the average time lag is 14 hours. This shows that the Sumbersewu Springs are dominated by diffuse flows. Average diffuse flow recession constant value (0.9942), fissure flow constant value (0.3575), and no conduit flow in Sumbersewu springs. Furthermore, with MRC also showed the same result, there was turbulent flow on the Sumbersewu Springs and the average duration of the lag time was 14 hours.

Kata Kunci : Karst Aquifer, Recession Component, Constant Recession , MRC