This report presents results from an optimization study of the Sacramento Basin
flood control system using the Hydrologic Engineering Center’s flood control
optimization software, HEC-FCLP. The objective of this study is to determine whether
significant benefits might be realized from an integrated operation of the system. To do
this, a deterministic mixed-integer program (MIP) is developed and applied to the 1995
and 1997 flood events. A MIP model, rather than a linear programming (LP) model, is
used to allow a more accurate representation of non-convex constraint sets.
The objective of the model is to minimize damage throughout the system by
deciding what releases should be from each reservoir during each time step of the
analysis. For this study a 6-hour time step is used. Penalties are incurred for exceeding
certain defined storage and flow levels or for exceeding the change-in-release constraints.
Results of this study show that when incremental inflows to the system are high,
Shasta Dam has an appreciable effect only as far downstream as the Bend Bridge gaging
station and the Feather/Yuba River system consisting of Oroville Dam and New Bullards
Bar Dam has an appreciable effect only as far as the Nicolaus gaging station. The results
imply that these subsystems could be optimized separately from the complete system
under these conditions.
This study illustrates that MIP is a useful tool for flood control optimization.
However, it is also found that solving complex systems using MIP can lead to excessive
computation times. Simplifications must be implemented whenever practical to reduce
the number of binary variables used by the model. |