| dc.description.abstract | Sub Daerah Aliran Sungai (Sub DAS) Cisangkuy merupakan bagian dari Daerah Aliran Sungai (DAS) Citarum Hulu yang memiliki fungsi penting dalam pengaturan tata air dan konservasi tanah, sekaligus berkembang sebagai kawasan pertanian dan perkebunan kopi. Pemanfaatan lahan pada wilayah berlereng dapat meningkatkan surface runoff atau surface runoff dan sediment yield atau sediment yield. Penelitian ini bertujuan memetakan tutupan lahan, menduga surface runoff dan sediment yield pada berbagai kelas tutupan lahan, serta merumuskan arahan pengelolaan perkebunan kopi berkelanjutan di Sub DAS Cisangkuy, Kabupaten Bandung.
Tutupan lahan tahun 2022 dipetakan menggunakan citra SPOT-7 dan algoritma Random Forest (RF). Pemodelan hidrologi dilakukan menggunakan Soil and Water Assessment Tool (SWAT) dengan input berupa tutupan lahan, jenis tanah, kemiringan lereng, data iklim, debit observasi, dan data lapangan. Wilayah model dibagi menjadi Hydrologic Response Unit (HRU) berdasarkan kombinasi tutupan lahan, jenis tanah, dan kemiringan lereng. Hasil model digunakan untuk membandingkan kondisi Business as Usual (BAU) dengan tiga skenario pengelolaan, yaitu Skenario 1 (SK1), Skenario 2 (SK2), dan Skenario 3 (SK3), berdasarkan perubahan surface runoff dan sediment yield.
Hasil klasifikasi menghasilkan delapan kelas tutupan lahan dengan Overall Accuracy (OA) atau akurasi keseluruhan sebesar 72,92%. Pertanian Lahan Kering Campur Semak Belukar (PLKSBL) merupakan kelas tutupan lahan terluas sebesar 7.447,09 ha, sedangkan agroforestri kopi dan monokultur kopi masing-masing teridentifikasi seluas 1.812,10 ha dan 1.710,68 ha. Evaluasi model SWAT menunjukkan kinerja yang cukup baik dengan nilai Nash-Sutcliffe Efficiency (NSE) sebesar 0,694, Koefisien Determinasi (R²) sebesar 0,932, Kling-Gupta Efficiency (KGE) sebesar 0,747, Root Mean Square Error (RMSE) sebesar 4,513, dan Percent Bias (PBIAS) sebesar 22,385. Hasil uji sensitivitas terhadap respons debit menunjukkan bahwa Maximum Canopy Storage (CANMX) merupakan parameter paling sensitif dengan nilai 0,468, diikuti Available Water Capacity (AWC) sebesar 0,172, Saturated Hydraulic Conductivity (SOL_K) sebesar 0,163, Soil Evaporation Compensation Factor (ESCO) sebesar 0,118, dan Soil Conservation Service Runoff Curve Number (CN2) sebesar 0,080.
Pada kondisi BAU, surface runoff rata-rata mencapai 719,63 mm/tahun, sedangkan sediment yield sebesar 48,87 ton/ha/tahun dengan total sekitar 1,05 juta ton/tahun. PLKSBL menjadi penyumbang sediment yield terbesar, yaitu sekitar 85,02% dari total sediment yield. Agroforestri kopi menunjukkan fungsi konservasi tanah dan air yang lebih baik dibandingkan monokultur kopi. Agroforestri kopi menghasilkan surface runoff sebesar 438,80 mm/tahun dan sediment yield sebesar 11,29 ton/ha/tahun, sedangkan monokultur kopi menghasilkan surface runoff sebesar 640,90 mm/tahun dan sediment yield sebesar 31,03 ton/ha/tahun. Pada lereng lebih dari 45%, sediment yield monokultur kopi mencapai 113,89 ton/ha/tahun, sedangkan agroforestri kopi sebesar 30,96 ton/ha/tahun.
Hasil perbandingan skenario menunjukkan bahwa SK2 merupakan arahan pengelolaan terbaik karena menerapkan pengelolaan berbasis HRU prioritas. SK2 menurunkan surface runoff menjadi 582,88 mm/tahun atau sebesar 19,00% dan sediment yield menjadi 7,90 ton/ha/tahun atau sebesar 83,84% dibandingkan BAU. Total sediment yield juga menurun menjadi 169.054,74 ton/tahun. Wilayah Prioritas 1 atau prioritas sangat tinggi mencapai 3.744,16 ha, terutama terdiri atas monokultur kopi, PLKSBL, dan perkebunan yang berada pada lereng lebih dari 25%. Pada lahan kopi berlereng curam, pengelolaan diarahkan pada penguatan agroforestri kopi, sedangkan tutupan lahan non-kopi diarahkan pada penerapan konservasi tanah dan air sesuai karakteristik lahannya. Evaluasi terhadap Rencana Tata Ruang Wilayah (RTRW) Kabupaten Bandung Tahun 2024–2044 menunjukkan bahwa sekitar 38,91% wilayah Prioritas 1 beririsan dengan kawasan yang memiliki fungsi perlindungan dan konservasi. Oleh karena itu, penerapan arahan pengelolaan perlu mempertimbangkan fungsi ruang serta didukung verifikasi lapangan.
Secara keseluruhan, pengelolaan perkebunan kopi berkelanjutan di Sub DAS Cisangkuy perlu dilakukan secara spasial dan selektif berdasarkan prioritas biofisik. Agroforestri kopi merupakan sistem pengelolaan yang lebih konservatif dibandingkan monokultur kopi, tetapi pengendalian surface runoff dan sediment yield pada skala Sub DAS juga memerlukan pengelolaan tutupan lahan non-kopi yang menjadi sumber utama sediment yield. | |
| dc.description.abstract | The Cisangkuy Sub-Watershed is part of the Upper Citarum Watershed and plays an important role in water regulation and soil conservation, while also supporting agricultural activities and coffee plantations. Land use on sloping areas may increase surface runoff and sediment yield. This study aimed to map land cover, estimate surface runoff and sediment yield under different land-cover classes, and formulate sustainable coffee plantation management directions in the Cisangkuy Sub-Watershed, Bandung Regency.
Land cover in 2022 was mapped using Satellite Pour l’Observation de la Terre-7 (SPOT-7) imagery and the Random Forest (RF) algorithm. Hydrological modeling was conducted using the Soil and Water Assessment Tool (SWAT), with land cover, soil type, slope, climate data, observed discharge, and field data as model inputs. The study area was divided into Hydrologic Response Units (HRUs) representing specific combinations of land cover, soil type, and slope. Model outputs were used to compare the Business as Usual (BAU) condition with three management scenarios, namely Scenario 1 (SK1), Scenario 2 (SK2), and Scenario 3 (SK3), based on changes in surface runoff and sediment yield.
The land-cover classification produced eight classes with an Overall Accuracy (OA) of 72.92%. Mixed Dryland Agriculture with Shrubs (PLKSBL) was the largest land-cover class, covering 7,447.09 ha, while coffee agroforestry and coffee monoculture covered 1,812.10 ha and 1,710.68 ha, respectively. SWAT model evaluation indicated acceptable performance, with a Nash-Sutcliffe Efficiency (NSE) of 0.694, coefficient of determination (R²) of 0.932, Kling-Gupta Efficiency (KGE) of 0.747, Root Mean Square Error (RMSE) of 4.513, and Percent Bias (PBIAS) of 22.385. Sensitivity analysis of discharge response showed that Maximum Canopy Storage (CANMX) was the most sensitive parameter, with a sensitivity value of 0.468, followed by Available Water Capacity (AWC) at 0.172, Saturated Hydraulic Conductivity (SOL_K) at 0.163, Soil Evaporation Compensation Factor (ESCO) at 0.118, and Soil Conservation Service Runoff Curve Number (CN2) at 0.080.
Under the BAU condition, average surface runoff reached 719.63 mm/year, while sediment yield reached 48.87 tons/ha/year, with a total of approximately 1.05 million tons/year. PLKSBL was the largest contributor to modeled sediment yield, accounting for approximately 85.02% of the total. Coffee agroforestry showed better soil and water conservation performance than coffee monoculture. Coffee agroforestry generated surface runoff of 438.80 mm/year and sediment yield of 11.29 tons/ha/year, whereas coffee monoculture generated 640.90 mm/year and 31.03 tons/ha/year, respectively. On slopes greater than 45%, sediment yield from coffee monoculture reached 113.89 tons/ha/year, compared with 30.96 tons/ha/year under coffee agroforestry.
Scenario comparison showed that SK2 was the best management scenario because it applied management interventions to priority HRUs. SK2 reduced surface runoff to 582.88 mm/year, equivalent to a 19.00% reduction relative to BAU, and reduced sediment yield to 7.90 tons/ha/year, equivalent to an 83.84% reduction. Total sediment yield decreased to 169,054.74 tons/year. The very high-priority area covered 3,744.16 ha, mainly consisting of coffee monoculture, PLKSBL, and plantation land located on slopes greater than 25%. Coffee plantations on steep slopes were directed toward strengthening coffee agroforestry systems, while non-coffee land-cover classes were directed toward soil and water conservation measures according to their respective land characteristics. Evaluation against the Bandung Regency Regional Spatial Plan (RTRW) for 2024–2044 showed that approximately 38.91% of the very high-priority area overlapped with protection and conservation zones. Therefore, the implementation of management directions should consider spatial functions and be supported by field verification.
Overall, sustainable coffee plantation management in the Cisangkuy Sub-Watershed should be implemented spatially and selectively based on biophysical priorities. Coffee agroforestry provides a more conservative management system than coffee monoculture. However, controlling surface runoff and sediment yield at the Sub-Watershed scale also requires management of non-coffee land-cover classes that contribute substantially to sediment generation. | |
