Natural flood management: Opportunities to implement nature‐based solutions on privately owned land

Abstract

The implementation of Natural Flood Management (NFM), as an example of a nature-based solution (NbS), is promoted as a risk reduction strategy to support sustainable flood risk management and climate change adaptation more widely. Additionally, as an NbS, NFM aims to provide further multiple benefits, such as increased biodiversity and improved water quality as well as improved mental health. The implementation of NbS often needs privateowned or managed land, yet can create conflicts between the different stakeholders which can undermine the social consensus required for successful implementation. Consequently, a main question is how the multiple benefits and requirements of NFM can be delivered to meet the different goals of the wide variety of stakeholders who must be involved. This article discusses the challenges and potential of implementing NFM as an alternative to the traditional technical mitigation measures in flood risk management. We outline four opportunities in the implementation of NFM: physical conditions of the catchment, social interaction, financial resources, and institutional setting. Their importance is then demonstrated and compared to different examples across the globe. Nevertheless, the core drivers reflect the social interaction and institutional setting and the role of stakeholders in the successful implementation of NFM.

Complex drivers of geomorphic response and habitat formation revealed in multiyear monitoring of Cosumnes River experimental floodplain reconnection

“…A significant component of the Netherlands' flood management strategy is the "Room for the River" project with strategic setback levees, expanded floodplains, and structural riverbed modifications [117]. By creating more space within the floodplain to reduce the peak flood stage downstream and facilitate faster drainage away from urban areas during high water levels, this innovative design ensured that rivers like the Rhine and Meuse had ample room to expand [24,118].…”

“…Further insights from global practices in river systems like the Tisza [119], Dijle [120], and Murray-Darling [121] underscore the importance of restoring natural habitats as a foundational element of their NbS strategies. A recurring theme across these and other regions is the challenge and necessity of balancing human needs, such as agriculture and urban development, with environmental conservation [118]. The dynamic nature of river systems, compounded by the uncertainties of climate change, emphasizes the importance of adaptive management, which involves ongoing monitoring and the flexibility to adjust strategies based on evolving conditions and new insights.…”

Reducing flood risk and improving system resiliency in Sacramento, California: overcoming obstacles and emerging solutions

“…Floodplains are dynamic systems, characterized by complex water and sediment interactions within a complex landscape, constantly changing with each flood event (Opperman et al, 2010;Serra-Llobet et al, 2022b). Research on a floodplain ecosystem created by an accidental breach along a tributary of the Sacramento River, the Cosumnes River, lead to a deeper understanding of the importance of these systems to fish and wildlife (Florsheim and Mount, 2002;Jeffres et al, 2008;Nichols and Viers, 2017;Thaler et al, 2023). Fisheries research in the Yolo bypass during and after flooding, further illustrated how these shallow connected areas with enhanced productivity can nourish fish leading to enhanced salmon growth rates and viability (Sommer et al, 2001;Takata et al, 2017).…”

“…Habitat restoration actions can be included in flood infrastructure improvement projects to provide ecological benefits and are also termed "multi-benefit projects". California legislators and managers, like their international counterparts (European Commission, 2007;Golfieri et al, 2017;Martin et al, 2021;Serra-Llobet et al, 2022b;Thaler et al, 2023), are increasing their support for these concepts, but project implementation is frequently slow paced and difficult. We present case studies from the lower Sacramento Region (Figures 1, 2) to provide an overview of the many challenges for completing these projects and ideas for overcoming obstacles.…”

Proactive river corridor definition: Recommendations for a process‐based width optimization approach illustrated in the context of the coastal Pacific Northwest

“…A river corridor is defined as the minimum area around a river that can sustain fluvial processes linked to channel migration which are vital to sustain both flood conveyance and a fluvial ecosystem with the diversity of habitat found in the river's undisturbed state. Giving a river sufficient space is the fundamental nature‐based solution (e.g., Cohen‐Shacham et al, 2016, 2019; Thaler et al, 2023) to reach‐scale river management, as this allows the river channel to dynamically adjust to changing inputs of water, sediment, and wood using its own power. A corridor provides critical flood conveyance (Church, 2006), produces topographic variability across the floodplain to support diverse aquatic and terrestrial habitats (Jones, 2006; Latterell et al, 2006), is a primary mechanism by which large wood is entrained into larger rivers (e.g., Abbe & Montgomery, 1996; Collins et al, 2012), and ultimately creates and maintains the complexity and diversity in channel and floodplain hydraulics that is necessary for the flourishing of aquatic organisms.…”