- Title
- Integrating sediment dynamics into physical habitat models
- Creator
- Almeida, G. A. M.; Rodríguez, J. F.
- Relation
- 18th World IMACS Congress and MODSIM09 International Congress on Modelling and Simulation. The 18th World IMACS Congress and MODSIM09 International Congress on Modelling and Simulation: Proceedings (Cairns, Qld 13-17 July, 2009)
- Relation
- http://www.mssanz.org.au/modsim09/authorsA-B.htm#a
- Publisher
- IMACS
- Resource Type
- conference paper
- Date
- 2009
- Description
- In the last years there has been increasing recognition of the key role played by sediment transport on the definition of physical habitat in streams. In particular, human-induced changes in sediment dynamics can cause severe changes on stream morphology (e.g. channel incision and/or widening) and on substrate composition (e.g. through sediment fining or coarsening processes), resulting in drastic consequences to stream ecological health. Taking into account sediment dynamics is especially important in the case of urban streams, where many restoration efforts fail to define morphologically stable conditions, mainly due to the lack of precise, reliable tools to predict stream morphological response. Despite the significant importance of sediment dynamics on habitat characteristics, it has not yet been integrated into physical habitat models (PHM). Available PHM rely on the assumption that both bed shape and substrate composition remain unchanged, which is in many instances patently flawed. This paper firstly proposes an integrative technique to incorporate sediment dynamics into PHM. The approach solves the one dimensional unsteady flow equations (full dynamic St. Venant equations) along with the sediment continuity equation. Sediment transport is calculated for different sediment size fractions in order to allow the simulation of changes in substrate composition (e.g. coarsening/fining). After each time step the updated morphology and sediment composition are then used to calculate habitat characteristics. Secondly, a conceptual simulation is presented to depict the general capabilities of the model to qualitatively predict morphological and substrate composition changes. The results of the proposed sediment-integrative model are compared with typical PHM results. Results have shown that significant differences between the results given by the proposed model and typical PHM in predicting habitat characteristics may be found. Also, the changes induced by sediment dynamics must be analyzed together and tracked over time in order to describe their consequences on the physical habitat. Accounting for sediment dynamics has proven to be a significant improvement in stream habitat assessment. Several cases of ecological response have shown to be mainly controlled by sediment dynamics.
- Subject
- physical habitat model (PHABSIM); sediment transport; ecological response model
- Identifier
- http://hdl.handle.net/1959.13/919476
- Identifier
- uon:8879
- Identifier
- ISBN:9780975840078
- Language
- eng
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