<p>This study proposes an integrated farm pond–pump–pipeline system to enhance agricultural water supply efficiency for paddy fields. Utilizing the Storm Water Management Model (SWMM), we simulated the conversion of open-channel branch lines into pressurized pipelines and evaluated the impact of varying pipeline diameters on irrigation efficiency and construction costs. Field survey data from the Baekma&#xa0;1 area And water supply information from Baekma Reservoir were used to develop the model. The simulation results revealed that the integrated system could achieve An irrigation efficiency of up to 55.4%, a marked improvement compared to the conventional open-channel system, which typically achieves around 37.9% efficiency. Among various pipeline diameters, while both 150‑mm And 500‑mm pipelines yielded similar efficiencies (approximately 52%), the 200‑mm pipeline attained the highest efficiency of 55.43% at a significantly lower construction cost. A cost-effectiveness analysis further indicated that optimizing pipeline diameter is critical, as higher diameters resulted in proportionately higher costs without commensurate efficiency gains. However, spatial analysis also demonstrated that irrigation efficiency decreases significantly in downstream fields due to increased distance from the reservoir, suggesting the need for additional measures to ensure uniform water distribution. These findings provide a robust foundation for developing more efficient and economically viable agricultural water supply systems, contributing to sustainable water resource management in irrigation networks.</p>