Analisis Benefit-Cost Ratio Finansial dan Lingkungan dari Pemanfaatan Eceng Gondok di Danau Toba, Kabupaten Samosir

Abstract

Pertumbuhan eceng gondok yang tidak terkendali di Danau Toba menimbulkan eutrofikasi, pendangkalan perairan, dan penurunan estetika kawasan wisata. Penelitian ini bertujuan mengidentifikasi biaya dan manfaat dari pemanfaatan eceng gondok oleh pemerintah dan masyarakat serta menganalisis benefit-cost ratio (B/C ratio) secara finansial dan lingkungan. Penelitian menggunakan pendekatan kuantitatif deskriptif dengan analisis biaya dan manfaat tahunan serta perhitungan B/C ratio secara finansial dan ekonomi berdasarkan data tahun 2025. Biaya finansial dihitung menggunakan market price method, sedangkan biaya lingkungan dihitung berdasarkan emisi gas rumah kaca mengacu pada IPCC (2006) dan harga kredit karbon di Bursa Karbon Indonesia. Penilaian manfaat dilakukan menggunakan market price method, replacement cost method, avoided cost method, shadow pricing method, dan contingent valuation method. Hasil penelitian menunjukkan bahwa total biaya finansial pemanfaatan eceng gondok mencapai Rp783.527.511 per tahun, sedangkan manfaat finansialnya sebesar Rp34.642.785 per tahun, sehingga diperoleh B/C ratio finansial sebesar 0,044. Setelah manfaat sosial dan lingkungan serta biaya lingkungan diperhitungkan, total manfaat meningkat menjadi Rp1.791.700.178 per tahun dengan total biaya sebesar Rp783.724.886 per tahun, sehingga diperoleh extended B/C ratio sebesar 2,286. Manfaat terbesar berasal dari peningkatan estetika Danau Toba, diikuti pengurangan biaya pendangkalan, penciptaan lapangan kerja, pencegahan kehilangan air, dan pengurangan kebutuhan oksigen sedimen. Hasil tersebut menunjukkan bahwa pemanfaatan eceng gondok belum efisien apabila hanya dinilai secara finansial, tetapi efisien ketika manfaat sosial dan lingkungan turut diperhitungkan.

The uncontrolled growth of water hyacinth in Lake Toba has caused eutrophication, sedimentation of waters, and a decline in the aesthetic value of the tourism area. This study aims to identify the costs and benefits of water hyacinth utilization by the government and the community, as well as to analyze the benefit-cost ratio (B/C ratio) from both financial and environmental perspectives. The research employed a descriptive quantitative approach, using an annual cost-benefit analysis and calculating the financial and economic B/C ratios based on 2025 data. Financial costs were calculated using the market price method, while environmental costs were calculated based on greenhouse gas emissions in accordance with IPCC (2006) guidelines and carbon credit prices on the Indonesia Carbon Exchange (IDXCarbon). Benefit valuation was conducted using the market price method, replacement cost method, avoided cost method, shadow pricing method, and contingent valuation method. The results show that the total financial cost of water hyacinth utilization reached IDR 783,527,511 per year, while the financial benefit amounted to IDR 34,642,785 per year, yielding a financial B/C ratio of 0.044. After accounting for social and environmental benefits as well as environmental costs, total benefits increased to IDR 1,791,700,178 per year with total costs of IDR 783,724,886 per year, resulting in an extended B/C ratio of 2.286. The largest benefit came from the improved aesthetic value of Lake Toba, followed by reduced sedimentation costs, job creation, prevention of water loss, and reduced sediment oxygen demand. These results indicate that the utilization of water hyacinth is not efficient when assessed solely from a financial standpoint, but becomes efficient when social and environmental benefits are taken into account.