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In studying rivers, physical and social science researchers tend to analyze water resource regulation at a national scale, treating “the state” as a monolithic entity mechanistically executing its regulatory code. Yet variation abounds in the interpretation and application of any national environmental policy. This study examines the complex geography of a small but crucial component of the U.S. Clean Water Act—compensatory stream mitigation—and how particular states and federal agency districts, and the individuals occupying key roles in those units of government, have interpreted the same national law in quite different social and environmental settings. The appearance of monotonic regulatory outcomes at a relatively coarse scale obscures a high degree of fine-scale heterogeneity. [ABSTRACT FROM PUBLISHER]

The typical framework for assessing human population distribution is across a flat, two-dimensional landscape. We alter this perspective by examining population distribution with respect to a third dimension, elevation. This alternative framework, termed hypsographic demography, conceptually provides a more complete visualization and understanding of population distribution. We apply hypsographic demography to North Carolina from the scale of the entire state to streams of different sizes. At the state scale, elevation and population are generally inversely correlated. The flat coastal plain contains the majority of the population at low elevations, whereas higher elevations contain smaller populations due to steep topography, which limits development. At the county scale, the historic location and expansion of cities was more closely correlated with observed patterns of hypsographic demography than elevation or topography. At the scale of the stream, the influence of topography on hypsographic demographics gains importance where topography limits the land available to develop. We use this approach to illustrate how changing the perspective for viewing population distribution can be applied to floodplain policy. [ABSTRACT FROM PUBLISHER]

Problem: Market mechanisms are emerging as means of offsetting the environmental effects of growth. Unfortunately, formal regulation of ecosystem markets is often separated from broader planning for urban development, resulting in offsets that are unsustainable in the face of future urban growth. Purpose: We aimed to assess how 2008 federal regulations that actively promote aquatic resource markets and encourage watershed planning to restore wetlands and streams damaged during development will affect reputedly efficient existing wetland and stream ecosystem markets in North Carolina. We explore how coordination between regulators and planners can improve long-term viability of market-created resource offsets and improve the ability of markets to respond to rapid urban growth. Methods: We analyzed new state and federal regulations and watershed planning efforts and convened a stakeholder forum including representatives of state and federal agencies, land developers, environmental groups, aquatic restoration companies, and academia. Results and conclusions: Problems with aquatic ecosystem markets in North Carolina stem from poor communication among local and regional planners, federal regulators, and state agencies. Institutional barriers and poor coordination cause federal regulatory decisions made without knowledge of land use plans or urban development patterns, faulty projections of market demand for aquatic offsets, and local land use plans that do not provide long-term protection for the offsets. Although regulators consider current surrounding land uses, they do not consider future land uses. We conclude that local land use projections should be required components of ecosystem restoration site plans and that state environmental management agencies' watershed plans should reflect urban development patterns. Takeaway for practice: Local planners should have input into the design of restoration sites providing environmental offsets as well as into state and regional ecosystem service market implementation plans. Federal, state, regional, and local agencies should facilitate and require information sharing, making planning and regulating ecosystem service markets part of the development process. Research support: This research was supported by the University of North Carolina's Institute for the Environment. [ABSTRACT FROM AUTHOR]

Understanding stream ecosystem processes necessitates an awareness of not only the physical, chemical, and biological systems, but also how these separate systems interact with each other. Using a nutrient retention and periphyton growth model coupled to a dynamic geomorphic template, we explore the potential role of channel shape, slope, and sediment texture on downstream nutrient retention, and attempt to determine if physical changes alone can drive or influence changes in nutrient-periphyton dynamics. The overall model results suggest there is a strong potential control of both nutrient retention and periphyton biomass by channel morphology. For example, with constant biochemical process rates, geomorphic variations alone could alter spatial distribution of nutrient retention over a 4-km study reach by between 11 percent and 52 percent. These results suggest channel geomorphology has a potentially strong influence on both nutrient retention and basal food sources in streams. [ABSTRACT FROM AUTHOR]