Abstract : Model tests of the existing Baldhill Spillway were conducted with symmetrical and asymmetrical spillway gate openings to determine for selected flow conditions the characteristics of the hydraulic pulsating pressures acting on the surface of the spillway chute and stilling basin apron. The 1:30-scale model simulated the entire width and length of the spillway crest, gates, chute, and stilling basin. The model was capable of simulating various anticipated upper and lower pool elevations and discharges as high as 65,000 cfs. Pulsating pressures were simultaneously measured with 30 surface-mounted transducers located in turbulent areas. Data were collected with a data acquisition system capable of collecting data for prescribed lengths of time and sampling at desired rates. Tests conducted to determine the vibration characteristics of the model chute and stilling basin indicated that their natural frequencies were too high to influence the magnitude of the measured hydraulic pulsating pressures. Initially, data were collected and sampled for various periods and frequencies to Dynamic loads, Stilling basins, Energy dissipators, Uplift forces. Pressure pulsations,