Technical Abstract: Conservation of freshwater systems is a paramount issue in the semi-arid Southwestern U.S. Over time, these systems have been degraded by anthropogenic activities and, more recently, are threatened by climate change. For water reallocation efforts to succeed in preserving these systems, a policy maker requires a clear understanding of the management options available and a means to evaluate these options. One potentially effective approach is a Decision Support System (DSS). For water management where ecosystem services are part of the decision-making criteria, a DSS should have the capability of evaluating management options through the use of a series of coupled physical and ecological models that generate ecosystems service outputs. These outputs can then be reflected as monetized societal values for purposes of analyzing management options. However, ecosystem service values generally remain unknown relative to market values for goods and services. A primary focus of this paper is the value of ecosystem services and how they are derived from a broad base of scientific information. A central tenet of our efforts is that ecosystem values are appropriately driven by sound scientific information and thus values and sound science are inextricably linked. We also focus on the process of transferring these values to other semi-arid areas.