Flood Control and Irrigation Outlet Works and Tailrace Channel for New Melones Dam , Stanislaus River, California, Hydraulic Model Investigation

摘要

This model study was conducted to develop measures to stabilize the tailrace channel. During the initial operation of the prototype FC&I outlet works, flows at a relatively low pool elevation resulted in failure of the 4-ft-diam derrick stone on the opposite bank. Several alternatives were tested in the 1:24-scale model. The recommended design consisted of the addition of deflector plates to the 18-ft-diam hoods and baffle blocks and an end sill added to the existing concrete chute and impingement pad. This design resulted in good energy disipation at all flows. The loadings exerted on the baffle blocks and end sill were measured in the 1:24-scale model. The loadings and pressures exerted on the deflector plates were measured in a 1:12-scale model. These loadings were used in the structural design of the elements of the recommended design. Although low-pressure zones were found in the deflector plate design, the high level of aeration that occurs when fixed-cone valves discharge into freely aerated hoods should reduce the potential for cavitation damage. Aeration of flow within the hoods was supplemented by air vents located between the deflector plates.