South Asian Journal of Social Studies and Economics

This study evaluates the impact of the Aek Sibundong irrigation system on agricultural productivity and regional development in Doloksanggul and Pollung subdistricts, Humbang Hasundutan Regency, North Sumatra, Indonesia. Recognizing irrigation as a cornerstone of rural infrastructure, the research assesses the effectiveness and economic viability of expanding irrigation coverage. Using a quantitative approach, data were collected in 2024 from 100 purposively selected farmers—50 with irrigated plots and 50 without—through structured interviews and questionnaires. Results indicate a significant yield difference, with irrigated farms producing 0.26 tons/ha more paddy annually. Economic analysis demonstrates strong investment viability, with a Net Present Value (NPV) of IDR 1.47 billion, a Benefit-Cost Ratio (BCR) of 3.82, and an Internal Rate of Return (IRR) of 32.29%. These findings affirm that upgrading irrigation infrastructure not only enhances productivity but also contributes substantially to local economic development. Policy recommendations include strengthening Water User Associations (WUAs), prioritizing irrigation expansion in underserved areas, and integrating irrigation planning into district-level development strategies to promote rural equity and climate resilience.