Geomorphological concepts and tools for sustainable river ecosystem management

✍ Scribed by Malcolm D Newson

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 551 KB
• Volume: 12
• Category: Article
• ISSN: 1052-7613
• DOI: 10.1002/aqc.532

✦ Synopsis

1. Under definitions of 'strong' sustainability, ecosystem protection and the valuation of natural goods and services figure prominently. These priorities also lie at the heart of the EC Water Framework Directive (WFD).

2. This paper explores the ability of fluvial geomorphology to describe, monitor and predict river channel conditions and behaviour at the basin and smaller scales. It also examines how geomorphology can help to create management 'tools' and work in interdisciplinary frameworks with freshwater ecology to assess instream physical habitat.

3. Systematic views of river basins and predictive techniques based on system drivers have been popular in fluvial geomorphology for 50 years. System states are seen as resulting from the balance between all relevant processes. However, channel dimensions and forms at a site are much harder to predict and their dynamic adjustment can occur rapidly, exhibiting 'threshold' behaviour.

4. Direct human impacts have been a focus of research but long-term monitoring of channel states and adjustments has been neglected; River Habitat Survey offers major opportunities in this respect, even though it was not designed specifically for geomorphological interpretation.

5. In the UK, local or 'reach'-scale channel adjustment is widespread, justifying a major empirical survey effort in support of management decisions. Channels are supply-limited in sediment terms, polycyclic in profile, confined within glacial and periglacial sediments and extensively manipulated by engineering modifications. Whilst system properties are vital to the choice of management options over long timescales, conditions on a hierarchy of smaller scales can confound the systematic attempts of geomorphologists to classify and predict channel states.

6. Freshwater ecologists have long appreciated the need for a scaled approach to river systems. This paper argues for extensions to shared data collection and analysis programmes before immutable policy becomes established around unfinished management tools. Adaptive management creates a more realistic medium for the use of uncertain geomorphological and ecological predictions.