Annual Water Yield Comparison Based on InVEST Modelling in Way Ratai Watershed, Lampung Province, Indonesia

The research delves into the intricate dynamics of annual water yield in the Way Ratai Watershed, Lampung Province, Indonesia, using advanced InVEST modeling techniques. By scrutinizing factors such as land use variations, land cover change, rainfall patterns, evapotranspiration, root depth, and plant available water capacity. The study uncovers critical insights into water availability that represents the total amount of water available and utilized in a specific area over a year. Through a detailed analysis, The research showcases the efficacy of land cover mapping using the Maximum Likelihood Classification (MLC) algorithm, validating with a high accuracy of 85.71% from Landsat imagery. Water yield modeling through InVEST reveals the influence of the studied factors, indicating higher water yields concentrated along river channels and coastal regions. The process, when compared to the wetness index derived from a digital elevation model, indicated consistency between high wetness indices in flatter regions and lower indices in mountainous areas, reflecting the flow dynamics from high to low elevations. The water yield model echoed these patterns, emphasizing elevated values along major river courses, emphasizing the significant impact of land use alterations on water yield dynamics, particularly within the unique setting of the Way Ratai Watershed.