Recent extreme floods on the Mississippi and Missouri Rivers (1993, 1995, 1997, 2007, 2010, and 2011) have motivated expansion of floodplain conservation lands. Within the state of Missouri, for example, there are more than 85,000 acres of State and Federally owned conservation lands in large-river floodplains. Floodplain lands are highly dynamic and challenging to manage. Variable exchanges of water, sediment, nutrients, and carbon between the river and the floodplain result in a diverse, productive, and ever-changing mosaic of habitat patches. In addition to conservation benefits, these lands have the potential to provide valuable ecosystem services like habitats, nutrient processing, carbon sequestration, and flood-water storage that produce economic values in terms of recreational spending, improved water quality, and decreased flood hazards. As hydrologic conditions in upstream watersheds vary due to climate change, land-use change, and changes in reservoir management - so-called non-stationary conditions - management challenges are compounded. Managers face questions about how decisions made today - such as which lands to acquire, design of vegetation restorations, decisions to invest in water-management infrastructure - will be affected by the hydroclimatic conditions of the future. The objective of this project is to formalize understanding of information needs for management of floodplain conservation lands so the right information is available at the right time.
Floodplains owe their high biodiversity and productivity to their dynamic interactions with rivers. At the same time, floodplains provide productive soils, level land, and abundant water resources that have driven agricultural, urban, and industrial development. Extreme floods on the Mississippi and Missouri rivers 1993 – 2011 provided opportunities for conversions of damaged floodplain lands from agriculture to conservation. Within the state of Missouri there are more than 85,000 acres of State and Federally owned conservation lands along the Missouri and Mississippi rivers, and additional lands are under various conservation easements. Management approaches range from active (water distribution and food crops for waterfowl production) to passive (for the benefit of biodiversity and ecological processes). The former involves extensive infrastructure for managing water, vegetation, and biota, whereas the latter aims to manage within a range of natural variability. Recently these conservation lands have also attracted attention for their potential to contribute to ecosystem services, in particular flood-risk reduction, nutrient processing, and carbon sequestration. Management of these floodplain lands has always been challenging because of the inherent dynamics of large rivers and their floodplains, and the fact that these lands exist within a mosaic of other land uses, dominantly agriculture. The prospect of managing floodplains for conservation objectives under non-stationary hydroclimatic conditions is even more daunting. Managers face uncertainties ranging from site-specific designs for water infrastructure to long-term land acquisition strategies. These decisions are central to managing floodplain lands for resiliency and adaptation to support conservation objectives, but they will also be informed by land and water-management decisions that are made by others, including adjacent land owners and upstream stakeholders. This project is designed as the first step needed to build a foundation for floodplain management and restoration decisions under nonstationary conditions. The project will address problem definition, hydroclimatic and geomorphic context, information needs, and initial development of tools and datasets to address those needs. We will begin with a workshop with managers of large-river floodplain conservation lands along the Middle Mississippi and Missouri Rivers – this will include state and federal agencies, and NGOs such as TNC and Ducks Unlimited. The workshop will be used to formalize management decision making in a conceptual model and to identify key information needs. We will include representatives from the dammed Upper Mississippi River, the open Middle Mississippi River, and the Missouri River to cover a large breadth of hydroclimatic and geomorphic conditions. The results of the first workshop will be used to define a science strategy which will include: a) formalizing and distributing one or more conceptual models, b) quantifying the range of hydroclimatic and geomorphic context in these rivers to establish representative conditions and where to focus future work, c) compiling historical hydrologic datasets and existing modeled hydrology based on downscaled climate-change data to compare historical and future predictions, d) develop basic analysis tools (with emphasis on coupled surface-water and groundwater models, wetland productivity) at the right level of resolution and complexity to address management questions, and e) pilot test the analysis tools in one or more locations to illustrate linkage and sensitivity of on-site conditions to historic and future conditions. With the results of a-e in hand, we will convene a second workshop to frame the results in a structured decision making context and define a strategy to fill information gaps.
