Use of Trapezoidal Weirs for Determining Seepage Discharge through Earth Dams

The paper presents a comprehensive analysis of the application of trapezoidal weirs coupled with automated measurement systems for the precise determination of seepage flow rates through earth dams at hydroelectric power plants. A key focus is placed on the hydraulic operating modes of these weirs, particularly the distinction between non-submerged and submerged conditions. The paper details the results of extensive laboratory studies conducted to quantify the impact of submergence on the discharge capacity of trapezoidal weirs. These experiments led to the derivation of a submergence coefficient, which is crucial for correcting standard discharge formulas. The findings demonstrate that neglecting this coefficient can lead to significant overestimation of actual flow rates, with errors exceeding 457%. The study proposes a refined formula and a corresponding graphical relationship to ensure accurate seepage monitoring, thereby enhancing the operational safety of hydraulic structures.