This Practice Paper identifies and critically examines three alternative approaches and associated design philosophies in response to the problem of urban flooding. It traces the reasons why these three approaches have emerged and discusses the attributes of each. Following this, it examines the potential of the green infrastructure approach as a means to realize ‘evolutionary resilience’ in designing urban environments for enhanced drainage management. The paper then contrasts the three alternative approaches to flood risk management and identifies some implications of advancing the green infrastructure concept in urban design activities.

Problem, research strategy, and findings: Local jurisdictions in 36 states have implemented transfer of development rights (TDR) programs to provide a market-based approach to preserving farmlands and open space while redirecting future development to targeted areas. Participation in TDR programs involves transaction costs over and above paying for TDR credits. Planners know little about the magnitude of transaction costs; who, if anyone, incurs a disproportionate share of these costs; or how transaction costs affect TDR participation. In this study we estimate the magnitude and distribution of transaction costs incurred by participants in 4 countywide TDR programs in Maryland, a TDR pioneer, by interviewing multiple participants in these programs. We fi nd that total transaction costs were high and borne largely by private sector participants, although we exclude the initial public sector costs of establishing the programs. Total transaction costs range from 13% to 21% of total TDR costs per transaction. Our findings are based on data reported by participants and may not be scalable; transaction costs, however, might deter landowners from participating in TDR programs, thus thwarting the land use goals of planners. Takeaway for practice: Planners should work to reduce transaction costs by better constructing TDR programs and providing greater information on TDR sale prices and potential buyers and sellers. Lowering and more fairly distributing transaction costs will make the TDR program a more successful approach to achieving land use goals and addressing the externalities arising from land use markets.