Analisa Pengaruh Perubahan Tata Guna Lahan DAS Welang Terhadap Debit Banjir Kali Welang Kabupaten Pasuruan, Jawa Timur

Rohman, Habibur (2020) Analisa Pengaruh Perubahan Tata Guna Lahan DAS Welang Terhadap Debit Banjir Kali Welang Kabupaten Pasuruan, Jawa Timur. Undergraduate thesis, Institut Teknologi Sepuluh Nopember Surabaya.

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Abstract

Lahan memiliki daya dukung terbatas sehingga penggunaannya perlu dijaga agar tidak terjadi degradasi lahan. penggunaan lahan yang salah akan memerlukan banyak perbaikan terutama jika degradasi lahan mencapai tahap irreversible. Pertumbuhan penduduk di area DAS Welang yang cepat membutuhkan daerah baru untuk pemenuhan kebutuhan primer sehingga menyebabkan lahan digunakan dengan cara – cara yang tidak sesuai dengan potensi dan melebihi daya dukungnya. Hal tersebut memberikan dampak terhadap sistem hidrologi suatu daerah aliran sungai (DAS) Welang. Tercatat kejadian banjir di kali Welang selama 6 tahun terakhir terjadi peningkatan frekuensi kejadian banjir. Upaya struktural sudah dilakukan namun masih tetap meningkat frekuensi kejadian banjir. Berdasarkan hal tersebut maka diperlukan kajian upaya mitigasi secara non struktural dengan melakukan penelitian ini. Penanganan secara non struktural diharapkan bisa menjadi salah satu solusi dengan mengidentifikasi perubahan tutupan lahan pada DAS Welang tahun 2007, 2011, 2014 dan 2017. Penanganan secara non struktural dengan melakukan Penelitian yang mengkaji pengaruh perubahan penggunaan lahan secara spasial dan temporal pada tahun 2007, 2011, 2014 dan 2017. Identifikasi tutupan lahan dengan metode interpretasi peta citra on screen. Analisa debit banjir dengan kala ulang 25 tahun dengan menggunakan metode HSS Nakayasu berturut – turut 2007, 2011, 2014, dan 2017 adalah 568,321 m3/dtk, 581,991 m3/dtk, 595,793 m3/dtk, 613,051 m3/dtk. Analisa pengaruh perubahan perubahan tata guna lahan terhadap debit banjir kali Welang menggunakan metode regresi linier berganda dengan 5 variabel independen dan 1 variabel dependen. Ditemukan bahwa perubahan tata guna lahan mengakibatkan nilai koefisien pengaliran (C) meningkat sehingga debit yang dihasilkan menjadi meningkat. Peningkatan debit banjir tertinggi pada tahun 2014 – 2017 dengan rata – rata peningkatan mencapai 17,489 m3/dtk. Dari hasil analisis korelasi metode regresi linier berganda dengan menggunakan software SPSS didapatkan nilai korelasi dengan rata – rata di atas 0,9. Hal itu menunjukkan bahwa keterkaitan antara tata guna lahan dengan debit banjir sangat kuat. Sedangkan untuk pengaruh tata guna lahan terhadap debit banjir sebesar 0,714 atau 71,4 % dilihat dari koefisien determinasi yang didapatkan. Kata Kunci : DAS Welang, Tutupan Lahan, Koefisien Limpasan, Debit Banjir, Regresi Linier Ganda=================================================================Land has limited supporting capacity so that its use should be kept in order that land degradation does not occur. Incorrect land use will require a lot of improvement especially if land degradation reaches an irreversible stage. Population growth in the Welang River Basin area rapidly requires new areas to fulfillment primary needs, thus causing land to be used in ways that are incompatible with its potential and exceed its supporting capacity. This has an impact on the hydrological system of a Welang watershed. Recirded flood events in Welang River during the last 6 years have increased the frequency of the incident. Structural efforts have been made but the frequency of flood events is still increasing. Based on this, it is necessary to study nonstructural mitigation efforts by conducting this research. Non-structural handling is expected to be one of the solutions by identifying land cover changes in the Welang River Basin in 2007, 2011, 2014 and 2017. Non-structural handling by conducting research that examines the effects of spatial and temporal land use changes in 2007, 2011, 2014 and 2017. Identification of land cover by the method of interpretation of image maps on screen. Flood discharge analysis with 25 return times using the HSS Nakayasu method in between years 2007,2011, 2014, and 2017 is 568,321 m3/sec, 581,991 m3/sec, 595,793 m3/sec, 613,051 m3/sec. Analysis of the effect of changes in land use on Welang flood discharge using multiple linear regression methods with 5 independent variables and 1 dependent variable. It was found that land use changes cause runoff coefficient (C) to increase so that the resulting discharge increases. The highest increase in flood discharge in 2014 - 2017 with an average increase of 17,489 m3 / sec. From the results of correlation analysis of multiple linear regression methods using SPSS software, the correlation values with an average above 0.9. This shows that the relationship between land use and flood discharge is very strong. While for the influence of land use to flood discharge is 0.714 or 71.4% seen from the coefficient of determination obtained. Keywords: Welang River Basin, Land Cover, Runoff Coefficient, Flood Discharge, Double Linear Regression

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: DAS Welang, Tutupan Lahan, Koefisien Limpasan, Debit Banjir, Regresi Linier Ganda
Subjects: G Geography. Anthropology. Recreation > G Geography (General) > G70.212 ArcGIS. Geographic information systems.
Q Science > QA Mathematics > QA275 Theory of errors. Least squares. Including statistical inference
T Technology > TC Hydraulic engineering. Ocean engineering > TC530 Flood control
Divisions: Faculty of Vocational > Civil Infrastructure Engineering (D3)
Depositing User: habibur rohman
Date Deposited: 02 Mar 2021 07:09
Last Modified: 02 Mar 2021 07:09
URI: https://repository.its.ac.id/id/eprint/74609

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