WATERSHED ETHICS: PROCESS LINKAGE IN PHYSICAL SYSTEMS AND IMPLICATIONS FOR STREAM MANAGEMENT

Stream channels are the integral linkages within a watershed, and are not merely physical conduits for the conveyance of runoff. Systems theory provides a framework for understanding complex relationships that determine the character of streams and their ecosystems. Understanding process linkages in fluvial systems is important in understanding the dynamics of water and sediment movement on hillslopes and in channels and is paramount in developing successful strategies for long-term sustainability, management, and land use in watersheds. Lack of attention to these linkages in physical systems results in landscape development in hazardous locations, harmful disruptions of natural diversity in riparian systems, and poorly conceived and unsuccessful stream restoration projects.

Issues of major concern include: 1) geomorphic thresholds for hillslope stability and channel equilibrium; 2) magnitude and frequency of catastrophic flood processes; and 3) the balance between inputs of sediment and water from the watershed to downstream channels. Any changes, natural and/or anthropogenic (i.e. land use) are likely to result in significant adjustments in downstream fluvial systems, including channel shape, channel pattern, and hydraulic geometry. Many of these adjustments prove disruptive to river ecosystems and anthropogenic concerns. Nevertheless, even in many cases where humans aren’t the primary cause of physical change in watersheds, they are often large contributors, whose actions exacerbate the problems associated with treating a watershed. The geologic community should address the need to understand and incorporate ethical values into the restoration and research process. Keeping streams and watersheds clean and physically functional requires multi-disciplinary thought and effort, including partnerships outside of science.

Examples will be used to illustrate process linkage in fluvial systems and to show ties to ecosystems. Better understanding of process linkages allows us to develop sound ecological management strategies for watersheds and help to predict how these systems may respond to changes in climate and land use in the future.