How to best build successful floodplain wetlands: lessons from eight projects

Jenn Hoskins
18th January, 2026

How to best build successful floodplain wetlands: lessons from eight projects

A purposefully buried tree vane effectively deflects erosive flow to stabilize the river-wetland connection, while also creating beneficial habitat for sport fish such as smallmouth bass (Micropterus dolomieu).

Image adapted from: Hawley et al. / CC BY (Source)

Key Findings

  • Historic deforestation and sediment accumulation have reduced floodplain capacity in southwest Ohio and northern Kentucky, impacting flood control and ecosystem health
  • Restoring floodplains by removing accumulated sediment can revitalize wetlands, offering a cost-effective alternative to traditional stormwater infrastructure
  • Strategic project design, including connection elevation and multi-stage treatment systems, maximizes benefits like flood reduction, erosion control, and water quality improvement
Floodplains, the relatively flat areas alongside rivers, historically provided significant benefits to both ecosystems and human societies. However, widespread deforestation and drainage projects have dramatically reduced the extent and functionality of these vital areas. This has led to increased flood risks, degraded water quality, and a loss of valuable habitat. Recognizing this, researchers from Sustainable Streams, alongside collaborators from the US EPA, US Fish and Wildlife Service, Clermont Soil & Water Conservation District, Adams-Clermont Solid Waste District, Cincinnati Office of Environment & Sustainability, and Ohio State University, investigated the potential of restoring floodplain wetlands as a cost-effective solution to these issues[1]. The core problem addressed by this research is the diminishing capacity of floodplains to manage water flow and provide ecosystem services. Traditionally, stormwater control relies heavily on “hard” infrastructure like pipes and concrete channels, which are expensive to build and maintain. The study explores whether restoring the natural function of floodplains – specifically by removing accumulated sediment – can offer a more sustainable and economical alternative. The study details the analysis of eight floodplain wetland restoration projects, assessing their success based on two key criteria: maximizing ecological and societal benefits, and maximizing economic efficiency and project longevity. The projects involved actively removing alluvial sediment (material deposited by rivers) from floodplains to re-establish connections between the wetland and the adjacent stream network. This sediment removal is crucial because decades of erosion, often exacerbated by upland deforestation, have caused floodplains to become disconnected, effectively reducing their ability to store floodwater and filter pollutants. The research identified key characteristics of ideal restoration sites. These include areas where sediment accumulation is significant, indicating a history of disconnection and potential for substantial storage capacity. They also emphasized the importance of design optimization, tailoring the restoration goals to specific local needs. For example, projects focused on nutrient reduction require different design considerations than those prioritizing flood control or habitat restoration. The study builds upon earlier work demonstrating the significant impact humans have had on landscape change and sediment movement[2]. That research showed that human activities have moved as much sediment in North America in the past century as natural processes do in 700-3000 years. The current study takes this understanding a step further by actively reversing some of that impact through sediment removal, effectively “undoing” some of the damage caused by past land use practices. Furthermore,[3] highlighted widespread alterations to floodplains globally, including conversion to agricultural land. This underscores the urgency of restoration efforts, as the loss of natural floodplain functions directly contributes to increased flood risks and ecosystem degradation. The projects analyzed in offer a practical approach to mitigating these risks by reclaiming lost floodplain area and restoring its natural capacity to absorb floodwater. The benefits identified through the eight projects were diverse. Restoring flood storage capacity and lowering flood elevations were primary outcomes, but the projects also improved habitat for fish and birds, enhanced water quality, and reduced erosion. Importantly, the removed sediment wasn’t simply discarded; in some cases, it was repurposed as high-quality topsoil for agricultural or landscaping use, creating an additional economic benefit. The modeling and construction phases revealed strategies for cost minimization. Efficient construction sequencing and innovative design approaches were critical to maximizing the economic return on investment. However, the study also acknowledged the challenges of achieving large-scale nutrient reduction targets solely through wetland restoration, as demonstrated by a separate project in Ohio where the cost of constructing sufficient wetlands to meet a 42% phosphorus reduction goal proved prohibitive[4]. This highlights the need for integrated approaches that combine wetland restoration with other nutrient management practices.

AgricultureEnvironmentEcology

References

Main Study

1) Success criteria comparison of eight implemented projects to improve the planning, design, and construction of floodplain wetlands

Published 16th January, 2026

https://doi.org/10.1371/journal.pwat.0000426

Related Studies

2) The human impact on North American erosion, sediment transfer, and storage in a geologic context.

https://doi.org/10.1038/s41467-020-19744-3

3) Human alterations of the global floodplains 1992-2019.

https://doi.org/10.1038/s41597-023-02382-x

4) Implementing constructed wetlands for nutrient reduction at watershed scale: Opportunity to link models and real-world execution.

https://doi.org/10.2489/jswc.2024.00077


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