The Intergovernmental Panel on Climate Change (IPCC) has predicted that changes in climate patterns (higher temperatures, changes in extreme precipitation events, higher level of humidity) will adversely impact water quality. The Climate Change Impacts on Iowa 2010 report shows that during the last few decades Iowa’s climate experienced significant variability in precipitation patterns, exhibiting wetter springs and dryer falls, an increase in dew point humidity levels, higher nighttime minimum temperatures, and a higher number of frost-free days. Furthermore, more intense rainfall increases the surface water runoff and subsurface drainage, thus resulting in more sediment and nutrient pollution of Iowa streams. Given the implications of climate change and variability on water and soil quality, it is important for watershed managers, stakeholders, and policymakers to understand not only the effectiveness of individual conservation practices in improving water quality but also the cost effectiveness of watershed-level policy programs designed for the implementation of conservation practices. The effectiveness of five conservation practices in reducing nonpoint source pollution will be modeled using the Soil and Water Assessment Tool (SWAT) watershed-scale water quality model, and compared across different climate scenarios. This information, together with cost-related information, will be used to simulate the cost efficiency of a reverse auction program. These results can offer insights for watershed managers willing to implement a program for nutrient (nonpoint source pollution) reductions. This study will consider the cost-efficiency of reverse auction program designed for improving water quality in the Boone River Watershed (BRW).This is the first study designed to address the effects of climate variability on the cost effectiveness of conservation policy design for nutrients in Iowa. The results of this project are intended to be presented in a conference setting and published in a peer reviewed journal with a focus on environmental and policy issues.