Improving ecosystem health in highly altered river basins: a generalized framework and its application to the Mississippi-Atchafalaya River Basin

Continued large-scale public investment in declining ecosystems depends on demonstrations of “success”. While the public conception of “success” often focuses on restoration to a pre-disturbance condition, the scientific community is more likely to measure success in terms of improved ecosystem health. Using a combination of literature review, workshops and expert solicitation we propose a generalized framework to improve ecosystem health in highly altered river basins by reducing ecosystem stressors, enhancing ecosystem processes and increasing ecosystem resilience. We illustrate the use of this framework in the Mississippi-Atchafalaya River Basin (MARB) of the central United States (U.S.), by (i) identifying key stressors related to human activities, and (ii) creating a conceptual ecosystem model relating those stressors to effects on ecosystem structure and processes. As a result of our analysis, we identify a set of landscape-level indicators of ecosystem health, emphasizing leading indicators of stressor removal (e.g., reduced anthropogenic nutrient inputs), increased ecosystem function (e.g., increased water storage in the landscape) and increased resilience (e.g., changes in the percentage of perennial vegetative cover). We suggest that by including these indicators, along with lagging indicators such as direct measurements of water quality, stakeholders will be better able to assess the effectiveness of management actions. For example, if both leading and lagging indicators show improvement over time, then management actions are on track to attain desired ecosystem condition. If, however, leading indicators are not improving or even declining, then fundamental challenges to ecosystem health remain to be addressed and failure to address these will ultimately lead to declines in lagging indicators such as water quality. Although our model and indicators are specific to the MARB, we believe that the generalized framework and the process of model and indicator development will be valuable in an array of altered river basins

SLIDES: The Era of River Anthropology: Social and Eco-Hydrological Science Connections and Capacity for Environmental Flows: US Case Studies

Presenter: Joe Flotemersch, US Environmental Protection Agency (EPA), Office of Research and Development 21 slide

Characterization of River Networks: A GIS Approach and Its Applications

Fluvial geomorphology provides the basis for characterizing complex river networks and evaluating biophysical processes within watersheds. Understanding the spatial organization of morphological features, their influencing processes, and resultant geomorphic diversity in stream networks are important for efficient restoration, river health assessment, and improving our knowledge of the resilience of riverine landscapes. River characterization is a means to determine the biophysical character of river networks but many methods are fraught with pitfalls, such as the use of incorrect variables and limited acknowledgment of the hierarchical organization of rivers. In this paper, a top‐down geographic information system‐based approach for determining the physical typology of river networks is outlined. A suite of multivariate analyses are used to develop a nomenclature for functional process zones (FPZs) — large tracts of the river network with similar hydro‐geomorphological character. Applied to the Little Miami River, Ohio, six distinct FPZs emerged, which had a nonuniform distribution along the river network. Some FPZs repeated downstream; others were rare in terms of total length and number of FPZ segments. The physical structure of the Little Miami River network was analyzed using a series of community metrics. Application of this approach for river monitoring, establishing reference conditions, as well as management of threatened and endangered species and asset trading is highlighted

Eight river principles for navigating the science-policy interface

Scientists and policymakers often work together to develop policy about the sustainable use of river ecosystems. River science plays an important role in developing river policy but how can key aspects of river science be conveyed as a heuristic to navigate the interface between river science and river policy? This paper introduces eight principles that encapsulate the key properties of rivers to consider during the development of river policy: (1) rivers are social-ecological systems; (2) river ecosystems provide valuable ecosystem services; (3) tools should support policy development; (4) knowledge of river ecosystems will always be incomplete; (5) social-ecological systems require interdisciplinary perspectives; (6) science is one of many inputs to be considered; (7) heterogeneity and variability are characteristic of river ecosystems; and (8) scale awareness is essential in river ecosystems. Whereas policy challenges are associated with each principle, consideration of principles in the context of the issue at hand may increase the robustness of river policy and enhance the sustainability of river ecosystems. The eight principles are evaluated in relation to the 'Water Act 2007' and the draft Murray-Darling Basin Plan to demonstrate how the principles can enhance policy development in the area of water allocation