To succeed, it must perform as a marsh. Specifically, it must function as well as or better than the marsh lost in the mitigation process. Without the functions, complexities, and dynamics of a marsh, it will be little more than an expensive garden. Land-use planners, managers, and scientists are working on these and other problems, but it will take time to solve them all. Meanwhile, we need to preserve existing wetlands and continue to look for ways to restore degraded ones.
Mitigation is a step in the right direction, but it's no panacea.