Wariunsora, Sisilia and Prof. Dr. Ir. Zaenal Kusuma,, S.U. and Prof. Ir. Didik Suprayogo,, M.Sc., Ph.D. (2023) Analisis Perubahan Tutupan Lahan Dan Dampaknya Terhadap Kesehatan Hidrologi Das Rejoso. Magister thesis, Universitas Brawijaya.
Abstract
DAS Rejoso merupakan salah satu DAS yang terletak di Kabupaten Pasuruan, Provinsi Jawa Timur (Indonesia). DAS Rejoso memiliki peran hidrologi strategis yang sangat penting bagi kehidupan masyarakat, terutama di Kabupaten Pasuruan dan daerah sekitarnya. Dengan meningkatnya kekhawatiran mengenai pengelolaan sumber daya air dan kelestarian lingkungan, pemahaman tentang perubahan penggunaan lahan dan kesehatan hidrologi DAS sangatlah penting untuk pengambilan keputusan yang tepat. Penelitian ini menggunakan teknik penginderaan jauh dan perangkat sistem informasi geografis untuk mengkarakterisasi beragam tipe tutupan lahan yang ada di DAS Rejoso. Citra satelit Landsat digunakan untuk meninterpretasi kelas tutupan lahan, termasuk hutan, agroforestri, lahan pertanian, sawah, tambak, dan pemukiman. Indikator kesehatan hidrologi seperti transmisi air, fraksi debit minimum dan maksimum terhadap total debit air, dan penyangga kejadian puncak hujan dianalisis secara sistematis sehubungan dengan kondisi perubahan tutupan lahan. Metode statistik korelasi digunakan untuk mengukur dampak perubahan tutupan lahan terhadap parameter hidrologi DAS. penelitian ini bertujuan untuk melihat bagaimana perubahan penggunaan lahan mempengaruhi ketahanan kesehatan hidrologi DAS. Hasil ini menunjukkan bahwa terdapat hubungan positif dan negatif antara perubahan tutupan lahan dengan indikator kesehatan hidrologi DAS Rejoso. Luas lahan hutan di DAS Rejoso cenderung meningkat dari tahun 2011 hingga 2021, disisi lain luas lahan agroforestri cenderung menurun. Kedua tutupan lahan tersebut memiliki potensi untuk dapat menyehatkan hidrologi DAS. Luas tutupan lahan tegalan yang berpotensi menurunkan kesehatan DAS cenderung meningkat. Lahan dengan tutupan pemukiman cenderung tidak mengalami perubahan sedang lahan sawah dan tambak cenderung menurun. Kondisi kesehatan hidrologi DAS Rejoso dengan indikator total hasil air per unit hujan menunjukkan kecenderungan menurun. Demikian pula ketersediaan air dalam sistem sungai di musim kemarau yang diindikasikan Fraksi debit minimum terhadap total debit sungai juga mengalami penurunan. Akibat menurunnya luasan agroforestri dan meningkatnya lahan tegalan dapat menyebabkan resiko terjadinya aliran puncak atau banjir dalam kondisi hujan intensitas tinggi dengan indikator fraksi debit maksimum terhadap total debit sungai juga meningkat. DAS Rejoso dari tahun 2011 hingga 2021 masih memiliki kemampuan tinggi dalam menyangga curah hujan sehingga tidak menyebabkan limpasan dan selanjutnya menjadi debit sungai saat terjadinya hujan lebat. Ini diindikasikan bahwa Buffering Indikator, Relative buffering indikator dan Buffering Peak Event masih tinggi (diatas 0.95) dan cenderung sedikit menurun di tahun 2021. Meningkatnya areal hutan, agroforestri, pemukiman dan tambak memberikan respon positif terhadap kesehatan hidrologi DAS. Di sisi lain, peningkatan tegal dan sawah mempunyai dampak negatif terhadap kesehatan hidrologi DAS.
English Abstract
Rejoso watershed is one of the watersheds located in Pasuruan Regency, East Java Province (Indonesia). The Rejoso watershed has a strategic hydrological role that is very important for people's lives, especially in Pasuruan Regency and surrounding areas. With increasing concerns regarding water resources management and environmental sustainability, an understanding of land use change and the hydrological health of the watershed is essential for informed decision-making. This study used remote sensing techniques and geographic information system tools to characterize the various land cover types present in the Rejoso watershed. Landsat satellite images were used to interpret land cover classes, including forest, agroforestry, farmland, paddy fields, ponds and settlements. Indicators of hydrological health such as water transmission, fraction of minimum and maximum discharge to total discharge, and buffer of peak rainfall events were systematically analyzed in relation to land cover change conditions. Correlation statistical method was used to measure the impact of land cover change on the hydrological parameters of the watershed. This study aimed to see how land use change affects the hydrological health resilience of the watershed. These results show that there is a positive and negative relationship between land cover change and hydrological health indicators of Rejoso watershed. The area of forest land in Rejoso watershed tends to increase from 2011 to 2021, on the other hand, the area of agroforestry land tends to decrease. Both land covers have the potential to be able to nourish the hydrology of the watershed. The area of moor land cover that has the potential to reduce watershed health tends to increase. Land with residential cover tends not to change while rice fields and ponds tend to decrease. The hydrological health condition of the Rejoso watershed with the indicator of total water yield per unit of rain shows a decreasing trend. Similarly, the availability of water in the river system in the dry season as indicated by the fraction of minimum discharge to total river discharge has also decreased. As a result of the decline in the area of agroforestry and the increase in moorland, the risk of peak flow or flooding in high-intensity rainfall conditions with indicators of maximum discharge fraction to total river discharge also increased. The Rejoso watershed from 2011 to 2021 still has a high ability to buffer rainfall so that it does not cause runoff and subsequently becomes river discharge during heavy rains. This is indicated that the Buffering Indicator, Relative buffering indicator and Buffering Peak Event are still high (above 0.95) and tend to decrease slightly in 2021. Increasing areas of forest, agroforestry, settlements and ponds provide a positive response to the hydrological health of the watershed. On the other hand, the increase in land and rice fields has a negative impact on the hydrological health of the watershed.
| Item Type: | Thesis (Magister) |
|---|---|
| Identification Number: | 0423040025 |
| Divisions: | S2/S3 > Magister Pengelolaan Tanah dan Air, Fakultas Pertanian |
| Depositing User: | Unnamed user with username nova |
| Date Deposited: | 13 Feb 2024 04:05 |
| Last Modified: | 13 Feb 2024 04:05 |
| URI: | http://repository.ub.ac.id/id/eprint/215966 |
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