Abstract

From the Executive Summary:

Climate models predict that storms and flooding will increase in frequency and severity in some regions. In light of these predictions, and with appreciation for the great uncertainty in these forecasts, communities will be looking for ways to improve their resilience to extreme events. Protection of natural areas and open space is one option.

Strategically protecting natural lands and open space can reduce damages from flooding and also provide environmental and social benefits, including improved water quality in streams and rivers, protection of groundwater sources, and enhanced recreational opportunities. Governments around the world are increasingly recognizing that “green infrastructure” can often be a costeffective substitute for the gray infrastructure—pipes, dams, levees—traditionally used to control flooding.

Nevertheless, many questions remain for communities. How much land should be protected, and where? How does the community balance flood protection and the co-benefits of green infrastructure in choosing which lands to target? And how does it maximize the net benefits of the actions—the benefits of flood protection, water quality, recreation, and so forth, minus the costs of protecting the land from development? Finally, how can the local government bring about this landuse change? What policies and approaches are feasible and cost-effective?

We address such questions in a case study of the Lower Fox River basin in Wisconsin. The Lower Fox River flows northeast from central Wisconsin to Green Bay, the largest freshwater estuary in the world. Water quality here has been a problem for decades, and many areas experience flooding. Scientists predict that these problems will worsen in the future with climate change: extreme precipitation events are expected to increase, leading to more flooding and exacerbating water pollution. Moreover, some parts of the basin are experiencing development pressures. The impervious surfaces that come with development tend to intensify flooding and some water quality problems, and flooding damages increase with the number of buildings located in floodplains.

Local government planners in other areas facing similar issues will find a framework here for determining the costs and benefits of using land-use policy to mitigate flood damage. While the case study is specific to Wisconsin, the methodology applies equally to other locations.