Predicted effects of residential development on a northern Idaho landscape under alternative growth management and land protection policies

Land use change driven by exurban development can lead to dramatic alterations in the structure and function of landscapes. Residential development outside of urban and suburban zones can disrupt agricultural and forest management operations and ecosystem processes, increase community wildfire hazard, deplete groundwater resources, and lead to social conflict. We assessed two policy tools, urban growth boundaries and agricultural use zoning, for their potential to help manage growth and sustain the rural landscape. Using a survey-based model, we simulated the effects of the two policy tools on land use change and compared the results with predictions of land use change for two rural counties (4794 km2) in northern Idaho developed in a previous project. We measured the effects of predicted exurban development using four measures: number of housing units predicted on productive agricultural lands, number of housing units predicted on a groundwater resource area, changes to a wildfire hazard index for residential structures, and the social acceptability of residential development patterns given current development preferences. The two policy tools impose in substantially different landscape-level residential development patterns when compared to the baseline change prediction and each other. Each tool resulted in a variety of tradeoffs between negative and positive effects among our measures of impact. Our findings demonstrate the importance of using multiple indicators to evaluate growth management and land protection policy tools for making land use planning decisions.