One-Arc-Second DEMs and Field Survey Data for Small Dams Using Terrain Metrics: A Comparative Study

Climate change has assured the critical role of small dams in water resource management by enhancing local water storage, flood control, and irrigation, thereby improving resilience to climate variability. This study evaluates the effectiveness of one-arc-second digital elevation models (DEMs) in determining reservoir volume-elevation data, comparing these satellite-derived data with field survey data, which are known to be costly and time-consuming. Focused on small dams, the research compares field survey data with data derived from the one-arc-second DEM to address the lack of validation for these studies in small reservoirs. The methodology involves analyzing ten reservoirs in two different locations, namely Erbil and Sulaymaniyah governorates in Northern Iraq, using ArcGIS and Remote Sensing for digital elevation model processing. The volume-elevation data for the reservoirs are determined using ArcGIS. Consequently, evaluations of terrain metrics and sensitivity analyses support the adoption of one-arc-second DEMs for determining volume-elevation data in early-stage dam planning and reservoir assessments. Key innovations include addressing the limitations of low-resolution DEMs by using a wider 5 km radius for terrain analysis, which enables a thorough evaluation of landform features. The Terrain Ruggedness Index (TRI) is introduced as a key metric for evaluating terrain complexity, regional variations, and sensitivity to absolute error percentages. Morris’s sensitivity analysis highlights TRI's significance as the decisive parameter by examining how different terrain parameters affect error rates. These advancements enhance the accuracy of reservoir and terrain evaluations, offering valuable insights for improved dam design and water resource management.