Modeling to improve environmental system management: Klamath River thermal refugia and the Sacramento -San Joaquin Delta

As the problems facing water resource planners become increasingly complex, the people involved in decision-making and management need new tools to help them identify, manage, and evaluate potential options. It is not often feasible or prudent to experiment directly with the physical system to assess the impacts of various management options. Instead, computer models have become commonplace. Computer models enable managers to evaluate the impacts of changes, both large and small, on their system prior to implementing those changes in the field, identify changes that have the most promise, and integrate knowledge of a problem in a way that promotes practical understandings and potential management insights. Managers should become familiar and comfortable with both simulation and optimization modeling. This will allow them to use a wide range of models, and to use models that are more applicable to particular problems and conditions.;This dissertation focuses on gathering data and developing computer models to aid decision makers in managing systems for environmental purposes. Two environmentally sensitive areas are focused on: the Sacramento-San Joaquin Delta, part of the San Francisco Estuary, and thermal refugia for salmonids on the Klamath River in Northern California. A basic background on thermal refugia is provided, followed by the results from an intensive monitoring study at two refugia on the Klamath River. The results from a preliminary UnTRIM modeling effort of the Beaver Creek site indicate that the refuge can be modeled if sufficient data is available. Two optimization models representing a system of refugia were developed to maximize the number of fish reaching the spawning ground (in-migration model) and the estuary (out-migration model). The results from the model could be used to identify which refugia provide the most benefit. Finally, a CALVIN modeling study of different Sacramento-San Joaquin Delta management options is presented. Management of the Delta requires a balancing of the interests that rely on it, but results from CALVIN indicate that there is sufficient economical adaptability in the California water system to allow for changes in Delta water policies.