Abstract
Land cover and land use changes can substantially alter hydrologic ecosystem services. Water availability and quality can change with modifications to the type or amount of surface vegetation, the permeability of soil and other surfaces, and the introduction of contaminants through human activities. Efforts to understand and predict the effects of land use decisions on hydrologic services-and to use this information in decision making-are challenged by the complexities of ecosystem functioning and by the need to translate scientific information into a form that decision makers can use. Hydrologic modeling coupled with scenario analysis can (1) elucidate hydrologic responses to anticipated changes in land use and (2) improve the utility of scientific information for decision making in a manner that facilitates stakeholder involvement. Using a combination of general concepts and concrete examples, this paper summarizes hydrologic consequences of land use changes and describes the use of modeling and scenario analysis to inform decision making. Two case studies integrate the concepts raised in the paper and illustrate how an approach employing modeling and scenario analysis offers a potentially powerful way to link research on hydrologic services with decision making.