Dampak Perubahan Tata Guna Lahan di Masa Depan Terhadap Neraca Air Irigasi pada Daerah Aliran Sungai Opak Menggunakan Soil and Water Assessment Tool
Fajar Ramadhan, Dr.Eng. Ansita Gupitakingkin Pradipta, S.T., M.Eng., IPM. ; Chandra Setyawan, S.T.P., M.Eng., Ph.D, IPM, ASEAN Eng., APEC Eng.
2026 | Skripsi | TEKNIK PERTANIAN
Perubahan tata guna lahan di Daerah Aliran Sungai (DAS) Opak mempengaruhi
dinamika hidrologi dan ketersedian air irigasi. Penelitian ini menganalisis dampaknya
terhadap neraca air pada tahun 2030, 2040, dan 2050 menggunakan model Soil
and Water Assessment Tool (SWAT). Data tata guna lahan berbasis citra satelit Landsat dan Sentinel-2 dianalisis
melalui Google Earth Engine (GEE). Untuk prediksi masa depan tata guna
lahan menggunakan plugin Modules for Land Use Change Evaluation (MOLUSCE)
berbasis Cellular Automata menghasilkan peta tata guna lahan tahun 2030,
2040, dan 2050. Hasil prediksi
diintegrasikan dengan parameter tanah, DEM, dan iklim
untuk mensimulasikan komponen neraca air DAS. Hasil
menunjukkan bahwa pada periode eksisting 2015-2025 terjadi peningkatan vegetasi sebesar
5.203,04 ha (3,70%) dan lahan terbangun sebesar 1.642,12 ha (1,17%), sementara
ladang/kebun menurun 5,09%. Pada proyeksi 2030-2050, lahan terbangun meningkat sebesar
5.436,07 ha (3,86%) dan vegetasi menurun sebesar 2.346,02 ha (1,67%). Model
SWAT menunjukkan kinerja baik dengan nilai NSE 0,601 dan R² 0,71. Hasil simulasi
menunjukkan bahwa debit sungai rata-rata mengalami penurunan di masa depan,
dari 22,92 m³/s pada kondisi baseline menjadi 14,97 m³/s (2030), 23,16
m³/s (2040), dan 16,33 m³/s (2050). Perubahan tata guna lahan mempengaruhi
distribusi komponen neraca air DAS dan
irigasi di masa depan, namun variasi curah hujan menjadi faktor dominan dalam
menentukan ketersediaan air. Hal ini
ditunjukkan dengan kecenderungan terjadi defisit air irigasi pada musim kemarau
kondisi far future (2050) di Daerah Irigasi Blawong, Pendowo, Payaman,
dan Simo.
Kata kunci:
DAS Opak, tata guna lahan, neraca air irigasi, GEE, MOLUSCE, SWAT.
Land use change in the Opak Watershed significantly affects hydrological
dynamics and irrigation water availability. This study aims to analyze its
impact on the water balance in 2030, 2040, and 2050 using the Soil and Water
Assessment Tool (SWAT) model. Land use data derived from Landsat and Sentinel-2
satellite imagery were processed using Google Earth Engine (GEE). Future land
use projections were generated using the Modules for Land Use Change Evaluation
(MOLUSCE) plugin based on Cellular Automata, resulting in land use maps for
2030, 2040, and 2050. These projections were integrated with soil parameters,
Digital Elevation Model (DEM), and climate data to simulate watershed water
balance components. The results indicate that during the baseline period
(2015–2025), vegetation increased by 5,203.04 ha (3.70%) and built-up areas
expanded by 1,642.12 ha (1.17%), while agricultural land decreased by 5.09%. In
future projections (2030–2050), built-up areas are expected to increase by
5,436.07 ha (3.86%), while vegetation is projected to decline by 2,346.02 ha
(1.67%). The SWAT model demonstrated good performance with an NSE value of
0.601 and an R² of 0.71. Simulation results show that the average river
discharge is projected to fluctuate but generally decrease in the future, from
22.92 m³/s under baseline conditions to 14.97 m³/s (2030), 23.16 m³/s (2040),
and 16.33 m³/s (2050). Land use changes influence the distribution of watershed
water balance components and future irrigation conditions; however, rainfall variability
remains the dominant factor affecting water availability. This is indicated by
the increasing likelihood of irrigation water deficits during the dry season
under far-future conditions (2050) in the Blawong, Pendowo, Payaman, and Simo
irrigation areas.
Keywords: Opak Watershed, land use change, irrigation water balance, GEE, MOLUSCE, SWAT.
Kata Kunci : Kata kunci: DAS Opak, tata guna lahan, neraca air irigasi, GEE, MOLUSCE, SWAT.
