Jurnal Teknologi dan Rekayasa Sumber Daya Air Vol. 1 No. 2 (2021) p. 489-500 © Jurusan Teknik Pengairan, Fakultas Teknik, Universitas Brawijaya JTRESDA Journal homepage: https://jtresda.ub.ac.id/ *Penulis korespendensi: auliarahmawatimuarifah@gmail.com Studi Perbandingan Metode Standardized Precipitation Index (SPI) dan Rainfall Anomaly Index (RAI) untuk Mengestimasi Kekeringan pada DAS Welang Aulia Rahmawati Muarifah 1 *, Donny Harisuseno 1 , Ery Suhartanto 1 1 Jurusan Teknik Pengairan, Fakultas Teknik, Universitas Brawijaya Jl. MT. Haryono No. 167, Malang, 65145, Indonesia *Korespondensi Email: auliarahmawatimuarifah@gmail.com Abstract: In Welang wateshed there are 20 villages in 5 sub districts in Pasuruan Regency and 19 villages in 9 sub districts in Malang Regency that are classified as drought prone areas. Therefore it is necessary to do drought analysis. This study aims to know the results of comparison meteorological drought index using Standardized Precipitation Index (SPI) and Rainfall Anomaly Index (RAI) and to know the suitability method when applied in Welang watershed for drought estimated. Also, spatial analysis using ArcGIS 10.3 aims to determine areas that are potentially affected by drought in the Welang watershed. The drought analysis results are SPI produced the minimum value drought index was -4.09 at 3-month period time scale. RAI was produced minimum index value of -3.93 at 1-month period time scale. After analyzing the hydrological drought index using the Standardized Streamflow Index (SSI), the correlation results are weak. Therefore, a qualitative comparison option was chosen by comparing the discharge pattern and monthly rainfall data where the RAI method was chosen as a more suitable method for use in Welang watershed. Spatial interpolation was performed by Inverse Distance Weighted (IDW) in years with the most extreme dry events, which are in 2007 and 2015. The result showed that 42 villages have the potential to be affected by meteorological drought and the dry months are August, September and October. Keywords: drought, distribution, rainfall anomaly index, standardized precipitation index, standardized streamflow index Abstrak: Pada DAS Welang terdapat 20 desa di 5 kecamatan di Kabupaten Pasuruan serta 19 desa di 9 kecamatan di Kabupaten Malang yang termasuk daerah rawan kekeringan. Maka dari itu perlu dilakukan analisis kekeringan. Studi ini bertujuan untuk mengetahui hasil perbandingan indeks kekeringan meteorologi metode Standardized Precipitation Index (SPI) dan Rainfall Anomaly Index (RAI) serta kesesuaian metode apabila diterapkan di DAS Welang dalam mengestimasi kekeringan. Selain itu analisis spasial dengan bantuan software ArcGIS 10.3 bertujuan untuk mengetahui daerah yang berpotensi terdampak kekeringan pada DAS Welang. Hasil analisis kekeringan Metode SPI menghasilkan indeks kekeringan paling minimum pada stasiun hujan Purwodadi sebesar -4,09 pada periode 3 bulanan.