Quantifying River Channel Stability at the Basin Scale

Abstract

This paper examines the feasibility of a basin-scale scheme for characterising and quantifying river reaches in terms of their geomorphological stability status and potential for morphological adjustment based on auditing stream energy. A River Energy Audit Scheme (REAS) is explored, which involves integrating stream power with flow duration to investigate the downstream distribution of Annual Geomorphic Energy (AGE). This measure represents the average annual energy available with which to perform geomorphological work in reshaping the channel boundary. Changes in AGE between successive reaches might indicate whether adjustments are likely to be led by erosion or deposition at the channel perimeter. A case study of the River Kent in Cumbria, UK, demonstrates that basin-wide application is achievable without excessive field work and data processing. However, in addressing the basin scale, the research found that this is inevitably at the cost of a number of assumptions and limitations, which are discussed herein. Technological advances in remotely sensed data capture, developments in image processing and emerging GIS tools provide the near-term prospect of fully quantifying river channel stability at the basin scale, although as yet not fully realized. Potential applications of this type of approach include system-wide assessment of river channel stability and sensitivity to land-use or climate change, and informing strategic planning for river channel and flood risk management.

Effective Representation of River Geometry in Hydraulic Flood Forecast Models

“…Furthermore, even at the catchment scale, it is not economically and practically feasible to measure along the total length of a number of streams, especially considering that changing inputs of water, sediment, and vegetation often lead to alterations of river morphology over short time scales. In particular, moderate annual peak floods lead to altered cross‐sectional geometry while rare infrequent events cause significant channel change (Buffington, ; Soar et al, ).…”

Lotic Ecosystem Health Assessments Using an Integrated Analytical Approach of Physical Habitat, Chemical Water Quality, and Fish Multi-Metric Health Metrics

“…Most chemical approaches, based on chemical measurements, could detect specific types of degradation only associated with chemical sources like eutrophication of nitrogen and phosphorus or organic or inorganic toxicants, but did not reflect the habitat alterations of stream environments or biological health [8][9]. For these reasons, integrated approaches using biological, chemical, and physical parameters were required for efficient stream health monitoring and management [10][11][12].…”

Human influence on the morphological adjustment of river channels: The evolution of pertinent concepts in river science

“…This thinking has been extended by the suggestion that channel network surveys can enable channel characteristics and adjustments to be considered as part of a more holistic, catchment‐based approach: River styles have been advocated for catchment characterization with implications for river rehabilitation in the Bega catchment, NSW, Australia (Brierley & Fryirs, ), and in Dumaresq Creek, NSW, Australia, a method of field survey could complement the existing stormwater management plan (Gregory, ). A basin‐scale study for characterizing and quantifying river reaches in terms of their geomorphological stability status and potential for morphological adjustment based on auditing stream energy suggested that emerging geographic information system tools offer the future prospect of fully quantifying river channel stability at the basin scale (Soar, Wallerstein, & Thorne, ). Particularly in urbanizing areas, the common approach to treat the symptoms by modifying and stabilizing the channel may, after channel network survey, be succeeded by a holistic, catchment‐based approach (Vietz, Walsh, & Fletcher, ).…”