Analisis Tren Perubahan Intensitas Hujan (Studi Kasus: Jakarta dan Bogor) - Tias Ravena Maitsa; Arno Adi Kuntoro; Deni Septiadi (Institut Teknologi Bandung, 2021)
Abstrak Penelitian ini mengkaji perbedaan Kurva Intensity-Duration-Frequency (IDF) di wilayah Jakarta dan Bogor yang dihitung berdasarkan data Stasiun Kemayoran dan Citeko, terhadap pendekatan Metode Alternating Block Method (ABM), Modified Mononobe, Standar Nasional Indonesia (SNI) Tata Cara Perhitungan Debit Banjir (SNI 2415-2016), dan SNI Tata Cara Perencanaan Drainase Permukaan Jalan (SNI 03-3424-1994). Hasil analisis menunjukkan bahwa curah hujan di wilayah kajian didominasi oleh kejadian ≤ 4 jam dengan rata-rata persentase volume hujan tertinggi pada dua jam pertama yakni 24,9% di Citeko dan 29,9% di Kemayoran. Rata-rata selisih besaran intensitas hujan berdasarkan data observasi dibandingkan dengan pendekatan Metode ABM serta Modified Mononobe mencapai >14%. Intensitas hujan yang dihitung berdasarkan SNI 03-3424-1994 memberikan hasil rata-rata yang lebih tinggi dibandingkan intensitas hujan observasi. Pada periode ulang 2, 5, dan 10 tahun, rata-rata perbedaan intensitas hujan berturut-turut sebesar 26,8 mm/jam, 17,6 mm/jam, dan 11,6 mm/jam di Citeko, serta 36,3 mm/jam, 24,7 mm/jam, dan 17,3 mm/jam di Kemayoran. Perhitungan yang sama menggunakan Modified Mononobe memberikan rata-rata intensitas yang lebih rendah yakni 17 mm/jam, 11,4 mm/jam, dan 8,9 mm/jam di Citeko, namun lebih tinggi sebesar 24,1 mm/jam, 47 mm/jam, dan 49,1 mm/jam di Kemayoran. Kajian ini menggarisbawahi perlunya pengembangan standar desain secara kontinu untuk menghadapi tantangan perubahan iklim. Kata-kata Kunci: Distribusi hujan, intensity-duration-frequency, intensitas hujan, alternating block method, modified mononobe. Abstract This study examines differences between Intensity Duration Curve (IDF) in Jakarta and Bogor Area, represented by Kemayoran and Citeko Rainfall Station, with the Alternating Block Method (ABM), Modified Mononobe, Indonesian National Standard (SNI) for Calculating Flood Discharge, and SNI for Road Surface Drainage Design. The results showed that the rainfall in Jakarta and Bogor mainly was less than 4 hours, with the highest percentage of rainfall volume at the first two hours, about 24.9% at Citeko and 29.9% at Kemayoran. The average bias of rainfall intensity calculated from observation data compared with ABM and Modified Mononobe was >14%. Average rainfall intensity, which was computed using SNI 03-3424-1994 was higher than rainfall intensity calculated from observation data. For the return period of 2, 5, and 10 years, the bias was about 26.8 mm/h, 17.6 mm/h, and 11.6 mm/h, respectively, at Citeko, and 36.3 mm/h, 24.7 mm/h, and 17.3 mm/h, respectively at Kemayoran. Same comparison using Modified Mononobe resulted in lower rainfall intensity about 17 mm/h, 11.4 mm/h, and 8.9 mm/h, respectively at Citeko, and 24.1 mm/h, 47 mm/h, and 49.1 mm/h, respective, at Kemayoran. This study underlined the importance of continuous development of design standards to cope with climate change. Keywords: Intensity-duration-frequency, rainfall distribution, rainfall intensity, alternating block method, modified mononobe.