Sediment traps that can greatly amplify the rate of sedimentation and automatically time the depositional process were set out in El Vado Lake and Morgan Lake (New Mexico), Lake Powell (Utah), and Pyramid Lake (Nevada). In El Vado and Morgan lakes, sediment fluctuations on the scale of days were responsive to local weather factors, with the deposition rate in Morgan Lake greater near the bottom of the water column than near the top. Sedimentation in El Vado and Pyramid lakes appeared to have some diurnal control. Sedimentation in Pyramid Lake and Lake Powell, the two lakes fed by large rivers, was strongly influenced by river discharge and showed lag effects proportional to the distance of sediment transport.