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Sumberdaya air Pulau Bintan sangat tergantung pada curah hujan, informasi ancaman kekeringan meteorologis sangat diperlukan dalam pengelolaan sumberdaya air di masa mendatang. Faktor kekeringan meteorologi merupakan faktor utama yang berpotensi menurunkan daya dukung sumberdaya air pulau. Pulau Bintan adalah pulau kecil dengan batuan penyusunnya granit dan batupasir Tuf, mempunyai daya-simpan dan berkelulusan air rendah. Aktifitas perekonomian dan tingkat pertumbuhan penduduknya yang tinggi, berpotensi menurunkan daya dukung sumberdaya air. Studi ini melakukan analisis curah hujan yang menghasilkan informasi ancaman kekeringan di pulau Bintan karena fenomena iklim El-Nino dan IOD+. Data dasar yang digunakan adalah data curah hujan observasi Kijang periode 1980 – 2017 serta data curah hujan satelit CHIRPS, dengan resolusi spasialnya 0,05 ° x 0,05 ° periode 1981 – 2017. Hubungan antara hujan dan fenomena iklim dianalisis dengan metode statistik fungsi waktu. Ancaman kekeringan dianalisis dengan Standardized Precipitation Indeks (SPI) periode defisit 3, 6 dan 12 bulan. Hasil analisis menunjukkan curah hujan di pulau Bintan sangat sensitif terhadap fenomena iklim, korelasi sangat kuat antara curah hujan dengan ENSO dengan nilai R= - 0,75 dan dengan IOD dengan nilai R=-0,75. Hal ini menyebabkan musim kemarau yang cukup panjang saat terjadi El-Nino di tahun 1982, 1997 dan 2015. Hasil analisis SPI menunjukkan fenomena El-Nino 1997 menyebabkan kekeringan dengan intensitas yang sangat tinggi (ekstrim kering), El-Nino 2015 menyebabkan kekeringan dengan intensitas tinggi, durasi panjang. El-Nino lemah tahun 2002, sedikit mempengaruhi curah hujan. Adanya ancaman kekeringan di Pulau Bintan apabila terjadi fenomena iklim El-Nino dan IOD (+). Ancaman semakin tinggi bila kedua moda fenomena terjadi bersamaan. Pengelolaan sumberdaya air di pulau Bintan perlu mempertimbangkan fenomenaiklim (ENSO dan IOD), agar dampak negatif yang akan ditimbulkan dapat ditekan.

Flooding represents around 32% of total disasters in Indonesia and disproportionately affects the poorest of communities. The objective of this study was to determine significant statistical differences, in terms of river catchment characteristics, between regions in West Java that reported suffering from flood disasters and those that did not. Catchment characteristics considered included various statistical measures of topography, land-use, soil-type, meteorology and river flow rates. West Java comprises 154 level 9 HydroSHEDS sub-basin regions. We split these regions into those where flood disasters were reported and those where they were not, for the period of 2009 to 2013. Rainfall statistics were derived using the CHIRPS gridded precipitation data package. Statistical estimates of river flow rates, applicable to ungauged catchments, were derived from regionalisation relationships obtained by stepwise linear regression with river flow data from 70 West Javanese gauging stations. We used Kolmogorov–Smirnov tests to identify catchment characteristics that exhibit significant statistical differences between the two sets of regions. Median annual maximum river flow rate (AMRFR) was found to be positively correlated with plantation cover. Reducing plantation land cover from 20 to 10% was found to lead to a modelled 38% reduction in median AMRFR. AMRFR with return periods greater than 10 years were found to be negatively correlated with wetland farming land cover, suggesting that rice paddies play an important role in attenuating extreme river flow events. Nevertheless, the Kolmogorov–Smirnov tests revealed that built land cover is the most important factor defining whether or not an area is likely to report flood disasters in West Java. This is presumably because the more built land cover, the more people available to experience and report flood disasters. Our findings also suggest that more research is needed to understand the important role of plantation cover in aggravating median annual maximum river flow rates and wetland farming cover in mitigating extreme river flow events.

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