A geomorphological framework for river characterization and habitat assessment

Abstract

ABSTRACT1. Methods to assess the physical habitat available to aquatic organisms provide important tools for many aspects of river management, including river health monitoring, determination of river restoration/rehabilitation strategies, setting and evaluating environmental flows and as surrogates for biodiversity assessment.2. Procedures used to assess physical habitat need to be ecologically and geomorphologically meaningful, as well as practicable. A conceptual methodological procedure is presented that evaluates and links instream habitat and geomorphology.3. The heterogeneity of habitat potential is determined within geomorphic units (such as pools, runs, riffles) by assessing flow hydraulics and substrate character. These two variables are integrated as hydraulic units -patches of uniform flow and substrate.4. This methodology forms a logical extension of the River Styles framework that characterizes river form and behaviour at four inter-related scales: catchments, landscape units, River Styles (reaches) and geomorphic units. As geomorphic units constitute the basis to assess aquatic habitat availability, and they form the building blocks of river and floodplain systems, intact reaches of a particular River Style should have similar assemblages of instream and floodplain habitat.5. An application of the hydraulic unit procedure is demonstrated in gorge, partly-confined and alluvial River Styles from the Manning catchment in northern New South Wales, Australia.

Overview and application of the National Aquatic Ecological Monitoring Program (NAEMP) in Korea

“…The physical structure of a river provides a template for biotic interactions and associations (Thompson et al, 2001). Thus, assessment of ecological condition and sound management of ecosystems depend on knowledge of the relevant biotic and abiotic settings and processes.…”

Influence of morphohydraulic habitat structure on invertebrate communities (Ephemeroptera, Plecoptera and Trichoptera)

“…Flow types were visually classified according , Thomson et al (2001), Grešková & Lehotský (2004) and Lehotský & Grešková (2005) and were identified as follows: 1. standing water (SW) -without flow; 2. scarcely, barely perceptible flow (SP) -indicated by smooth water surface, surface flow noticeable by movement of suspended material; 3. smooth surface flow (S) -smooth water surface, flow takes place throughout the water profile, turbulent movements of fine suspended particles; 4. rippled (surface) (R) -low transverse ripples on the surface moving down the stream; 5. unbroken standing waves (USW) -undular waves form a surface with unbroken water; 6. broken standing waves (BSW) -standing waves witch break at the crest; 7. backwater (BW) -smooth swirl backwater flow. Based on flow velocity and depth Froude and Reynolds number was calculated.…”

“…A number of hierarchical classifications which link the catchment and channel have been proposed as a tool for an effective river investigation and management, e.g. Frissell et al (1986); Pool et al (2002); ; Maddock (1999); Thomson et al (2001); Brierley et al (2002). These works have been used as conceptual guides for the development of the River Morphology Hierarchical Classification framework (RHMC) by Lehotský & Grešková (2003) In RHMC seven levels are identified: 1. catchment; 2. zone; 3. segment; 4. channel-floodplain unit; 5. river reach; 6. morphological unit; 7. morphohydraulic unit.…”

An Ecological Flow Assessment Framework: Building a Bridge to Implementation in Canada

“…Geomorphic stream classification systems (e.g., form-based (Rosgen, 1994), process-based (Montgomery and Buffington, 1997), form and process-based (Thomson et al, 2001)) provide a starting point for understanding the interrelated geomorphic processes that shape channels and, as such, the potential effects of changing flows (and/or sediment regime) on channel form and function. Hill et al (1991) stated that "to determine which flow patterns are needed to maintain a stream system, one must match the respective valley bottom type, riparian type, and floodplain and channel type to the hydrologic processes that control form and function.…”