Pustaka Ilmiah Universitas Padjadjaran

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Debit Air Limpasan Sebagai Risiko Bencana Perubahan Luas Sungai Tugurara Di Kota Ternate, Provinsi Maluku Utara

Sungai Tugurara adalah salah satu Daerah Aliran Sungai (DAS) pada Gunungapi Gamalama yang memiliki risiko bencana terhadap masyarakat seperti luapan banjir lahar. Sungai Tugurara berada disebelah utara Kota Ternate, tepatnya di Kecamatan Ternate Utara, yang dihuni oleh masyarakat di tiga Kelurahan yaitu, Kelurahan Tubo, Kelurahan Akehuda dan Kelurahan Dufa-Dufa. Kawasan Sungai Tugurara secara geologi merupakan daerah aliran lahar muda yang terjadi pada tahun 1840, 1897 dan 1907 dengan material tidak kompak. Kondisi tersebut apabila terjadi limpasan (runoff) dapat menyebabkan perubahan luas Sungai Tugurara. Penelitian ini menggunakan metode pengujian statistik korelasi product moment dan uji signifikan korelasi product moment. Hasil penelitian diketahui bahwa debit air limpasan berhubungan dengan perubahan luas Sungai Tugurara. Perubahan luas Sungai Tugurara menjadi lebih besar karena besarnya debit air limpasan mampuh menggerus batuan pada dinding sungai dan menyebabkan longsoran dinding sungai serta membawah material disepanjang sungai sebagai bencana luapan banjir lahar pada kawasan permukiman ditiga kelurahan pada tahun 2011. Dengan demikian perubahan luas Sungai Tugurara, terjadi sangat signifikan. Hasil uji korelasi product moment diketahui bahwa nilai koefisien korelasi sangat kuat sebesar 0.994 dan signifikan adanya nilai r hitung (rh > rt) r tabel sebesar 0.950, maka Ha diterima dan nilai koefisien dapat diberlakukan pada populasi sampel diambil.

Tugurara river is the watershed located at Gamalama Volcano that have disaster risk such as the lahar to the community. Tugurara river located to the North of the city of Ternate, precisely in the district of North Ternate, which was inhabited by people in three village namely, Tubo Village, Akehuda Village and Dufa Dufa Village. Tugurara river region is an area that geologically consist of young lahar flows that occurred in 1840, 1897 and 1907 with the unconsolidated material. If there is a runoff caused changes of Tugurara river area. This study uses statistical methods i.e. pearson product moment correlation and significant test of product moment correlation. results revealed that runoff water correlate with extensive changes of Tugurara river area. Extensive changes of Tugurara river area becomes greater because the amount of runoff water discharge erode the rock on the river wall and causing lanslide the river wall as well as presenting any material river wall along the river as a catastrophic outburst flood lava on a residential area in three villages in 2011. Therefore changes Tugurara river area, occurred very significant. The results of the coefficient of product moment correlation test is known that the correlation is very strong for 0.994 and significantly their values count r (rh> rt) r tables for 0.950, so Ha is received and the value of the coefficient can be imposed on a population sample is taken.