Modelling sediment deposition and phosphorus retention in a river floodplain |
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| Authors: | M González‐Sanchis J Murillo A Cabezas J E Vermaat F A Comín P García‐Navarro |
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| Affiliation: | 1. Universitat Politècnica de València, Valencia, Spain;2. LIFTEC CSIC–University of Zaragoza, Zaragoza, Spain;3. Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany;4. Institute for Environmental Studies, VU University Amsterdam, Amsterdam, The Netherlands;5. Pyrenean Institute of Ecology–CSIC, Zaragoza, Spain |
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| Abstract: | Phosphorus (P) is one of the major limiting nutrient in many freshwater ecosystems. During the last decade, attention has been focused on the fluxes of suspended sediment and particulate P through freshwater drainage systems because of severe eutrophication effects in aquatic ecosystems. Hence, the analysis and prediction of phosphorus and sediment dynamics constitute an important element for ecological conservation and restoration of freshwater ecosystems. In that sense, the development of a suitable prediction model is justified, and the present work is devoted to the validation and application of a predictive soluble reactive phosphorus (SRP) uptake and sedimentation models, to a real riparian system of the middle Ebro river floodplain. Both models are coupled to a fully distributed two‐dimensional shallow‐water flow numerical model. The SRP uptake model is validated using data from three field experiments. The model predictions show a good accuracy for SRP concentration, where the linear regressions between measured and calculated values of the three experiments were significant (r2 ≥ 0.62; p ≤ 0.05), and a Nash–Sutcliffe coefficient (E) that ranged from 0.54 to 0.62. The sedimentation model is validated using field data collected during two real flooding events within the same river reach. The comparison between calculated and measured sediment depositions showed a significant linear regression (p ≤ 0.05; r2 = 0.97) and an E that ranged from 0.63 to 0.78. Subsequently, the complete model that includes flow dynamics, solute transport, SRP uptake and sedimentation is used to simulate and analyse floodplain sediment deposition, river nutrient contribution and SRP uptake. According to this analysis, the main SRP uptake process appears to be the sediment sorption. The analysis also reveals the presence of a lateral gradient of hydrological connectivity that decreases with distance from the river and controls the river matter contribution to the floodplain. Copyright © 2014 John Wiley & Sons, Ltd. |
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| Keywords: | phosphorus retention model validation sediment deposition floodplain numerical modelling |
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