Evaluating Water Management Strategies with the Systems Impact Assessment Model: SIAM Version 3

This report is preliminary and has not been reviewed for conformity with U.S Geological Survey editorial standards. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although the software referenced by this report has been used by the U.S. Geological Survey, no warranty, expressed or implied, is made by the USGS as to the accuracy and functioning of the software and related materials nor shall the fact of distribution constitute any such warranty, and no responsibility is assumed by the USGS in connection therewith. Preface This booklet serves as an introduction to the SIAM, a System Impact Assessment Model for riverine ecosystems. SIAM is an integrated set of models used to address significant interrelationships among selected physical (temperature, microhabitat, and geomorphic features), chemical (dissolved oxygen) and biological variables (young-of-year salmonid production), and stream flow in a river. SIAM has been developed for the lower Klamath River from Klamath Falls, Oregon, to the river's mouth on the California coast using data and models selected to be appropriate for the riverine portion of that study area. SIAM is only as good as the data, models, and its users allow it to be. This document highlights the important assumptions and limitations of these data and models so that use may be enlightened as well as productive. We have tried to assure the quality of the data and models integral to SIAM for the Klamath River; however, we stress that common sense may not be left behind in applying SIAM for any specific analysis. Users must be vigilant in making sure that the results logically follow from the premises. A warranty is neither stated nor implied. SIAM represents only a small portion of any true ecosystem analysis and its results must be considered in context with numerous other ecological, institutional, and political realities. SIAM is not meant to be a decision-making device, but it is rather a decision aid. It is infeasible to model all important resource impacts and impossible to anticipate all possible water supply situations. Discretion and informed guidance will remain a necessary ingredient for appropriate SIAM use. We (USGS) continue to provide training & support for SIAM in partnership with other users, in particular the US Bureau of Reclamation and the US Fish & Wildlife Service. However, given the nature of the decision-making structure evolving in the Klamath …