This is a depiction of a disconnected and non-functional versus an ecologically functional floodplain. Ecologically functional floodplains flood regularly without constructed barriers or incised main channels that prevent water from entering the floodplain during high-flow events. They are also capable of supporting plant and animal communities native to that region.
A review written by BBE researcher Chis Lenhart, grad student Brad Gordon, and contributing author Olivia Dorothy has been recognized by peer-review journal Water as an editor's choice article. Read the full review titled Nutrient Retention in Ecologically Functional Floodplains by clicking here.
Nutrient loads in fresh and coastal waters continue to lead to harmful algal blooms across the globe. Historically, floodplains—low-lying areas adjacent to streams and rivers that become inundated during high-flow events—would have been nutrient deposition and/or removal sites within riparian corridors, but many floodplains have been developed and/or disconnected. This review synthesizes literature and data available from field studies quantifying nitrogen (N) and phosphorus (P) removal within floodplains across North America and Europe to determine how effective floodplain restoration is at removing nutrients. The mean removal of nitrate-N (NO3−-N), the primary form of N in floodplain studies, was 200 (SD = 198) kg-N ha−1 year−1, and of total or particulate P was 21.0 (SD = 31.4) kg-P ha−1 year−1. Based on the literature, more effective designs of restored floodplains should include optimal hydraulic load, permanent wetlands, geomorphic diversity, and dense vegetation. Floodplain restorations along waterways with higher nutrient concentrations could lead to a more effective investment for nutrient removal. Overall, restoring and reconnecting floodplains throughout watersheds is a viable and effective means of removing nutrients while also restoring the many other benefits that floodplains provide.