April 2010 Article: “Ecologically Functional Floodplains: Connectivity, Flow Regime, and Scale,” by Jeffrey J. Opperman, Ryan Luster, Bruce A. McKenney, Michael Roberts, and Amanda Wrona Meadows.
Recent stream restoration efforts seem to place a lot of emphasis on designing to a single characteristic such as bankfull flow. The ideas in this article offer a more complex, nuanced view which looks at the flood regime in its totality.
The authors propose a conceptual model encompassing three basic elements: (1) hydrologic connectivity between the river and the floodplain, (2) a variable hydrograph that reflects seasonal precipitation patterns and retains a range of both high and low flow events, and (3) sufficient spatial scale to encompass dynamic processes and for floodplain benefits to accrue to a meaningful level.
For streamflow, the authors consider three kinds of representative floods. The “floodplain activation flood” is a small-magnitude flood that occurs relatively frequently and supports many of the processes ascribed to overbank flow pulses. The “floodplain maintenance flood” is a higher magnitude flood capable of performing geomorphic work including bank erosion and deposition on the floodplain that creates and maintains floodplain surfaces and contributes to heterogeneous floodplain topography. The third kind, “floodplain activation floods,” are rare, high-magnitude events that result in extensive geomorphic changes.
[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]