Evaluation of extremal hypotheses in an undeveloped alluvial river
| Autor: | Peter Goodwin, Diego Caamaño, Andrew W. Tranmer |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
geography
geography.geographical_feature_category 010504 meteorology & atmospheric sciences Earth science 0208 environmental biotechnology Geography Planning and Development Fluvial system 02 engineering and technology Alluvial river Structural basin 01 natural sciences 020801 environmental engineering Work (electrical) Earth and Planetary Sciences (miscellaneous) General Earth and Planetary Sciences Geology 0105 earth and related environmental sciences |
| Zdroj: | Progress in Physical Geography: Earth and Environment. 44:514-533 |
| ISSN: | 1477-0296 0309-1333 |
| DOI: | 10.1177/0309133319886721 |
| Popis: | Recent work in the undeveloped Rio Murta Basin, located in Chilean Patagonia, identified an evolutionary trend in the fluvial system as it progresses toward and away from dynamic equilibrium. A location-for-time-substitution model employed over the longitudinal extent of a 16 km study site assessed the performance of extremal hypotheses in identifying dynamic equilibrium conditions. Numerous extremal hypotheses were successful in identifying the spatial trend, but no means were available to discern differences between them. Thus, this study uses field measurements within the evolutionary trend to propose a new metric for evaluating extremal hypotheses. A thorough review and synthesis of the extremal approach are additionally presented. The new method compares theoretical predictions against field-measured values to determine which extremal hypothesis is most effective in identifying the condition of dynamic equilibrium in a gravel-bed river. Channel width and depth are identified as the dependent stream variables that uniquely differentiate most extremal hypotheses from one another. The results indicate that extremal hypotheses based on energy metrics of the flow are most successful, with the strongest support for minimum kinetic energy and minimum specific stream power. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|