Physical and Mathematical Modelling of a River Diversion Scheme

ABSTRACT

A scheme for withdrawal of water from the Sacramento River in California, USA, without the construction of a dam was investigated using physical models of the river at two different scales. The first physical model was used to study sediment problems associated with large water diversions from this tidally-influenced river which carries a large amount of bed load. Ground-up walnut shells were used to represent bed load sediment. This model of 8.4 km of the river was a distorted model. The second model was undistorted and represented about 3 km of river. It was used to study flow patterns at the diversion and in the diversion channel. A laser-doppler velocimeter and an electromagnetic meter were used to measure velocities in this model. A mathematical model of the river was used to provide data for use in operating the physical models. These studies provided technical information for evaluation of various alternative designs for the diversion structure and fish screening facilities.