The coefficient of discharge (Cd) for trapezoidal (Cipolletti), triangular (V-notch), and sharp-crested rectangular weirs is experimentally investigated in this study, with a focus on its function in enhancing the accuracy of discharge forecast for water resource management. Weirs, which are essential for measuring flow in open channels, measure discharge using Cd, a dimensionless factor that takes energy losses and flow contractions into consideration. Insights for improving flow calculations in real-world applications including irrigation, flood control, and water supply systems are provided by the study, which emphasizes how Cd changes with weir geometry and hydraulic conditions. Discharge rates were measured and the head above the weir crest was systematically changed in laboratory testing. Point gauges were used to measure head precisely, and volumetric techniques were used to guarantee precise discharge quantification. In order to isolate the effects of head and geometry on Cd, the experimental setting reduced the number of external variables. Different Cd patterns were found for each type of weir based on data analysis. As head increased, triangular weirs showed a significant rise in Cd, which was explained by progressive flow contraction adjustments. Sharp-crested rectangular weirs, on the other hand, showed predictable flow patterns and kept Cd values comparatively constant across a range of heads. In contrast to both rectangular and triangular arrangements, the trapezoidal (Cipolletti) weir, which was constructed with 1:4 sloping sides to counteract end contractions, showed intermediate Cd values because of its hybrid shape. The study found differences between experimental Cd values and predictions from theoretical models and empirical formulas, highlighting the drawbacks of simplified equations. For example, rectangular weir formulas more nearly matched experimental data, whereas triangle weir models underestimated Cd at higher heads. These results highlight the need for empirical calibration to take into consideration complications seen in the actual world, like dynamic flow behavior and subtle geometrical details. By bridging theoretical models with experimental validation, the research enhances understanding of hydraulic performance across weir types. The derived Cd values provide actionable data to refine design guidelines, ensuring accurate discharge estimation in field applications. Practically, this supports the optimization of hydraulic structures, such as improving spillway efficiency in flood management or enhancing water allocation in irrigation networks. The study advocates for context-specific calibration of Cd in engineering practices, balancing theoretical assumptions with empirical observations to achieve reliable, site-specific solutions. Ultimately, the work advances water resource management by strengthening the precision of flow measurement and the resilience of hydraulic infrastructure.