Simulating sediment discharge at water treatment plants under different land use scenarios using cascade modelling with an expert-based erosion-runoff model and a deep neural network

<p>Excessive sediment discharge in karstic regions can be highly disruptive to water treatment plants. It is essential for catchment stakeholders and drinking water suppliers to limit the impact of high sediment loads on potable water supply, but their strategic choices must be based on simula...

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Main Authors: E. Patault, V. Landemaine, J. Ledun, A. Soulignac, M. Fournier, J.-F. Ouvry, O. Cerdan, B. Laignel
Format: Article
Language:English
Published: Copernicus Publications 2021-12-01
Series:Hydrology and Earth System Sciences
Online Access:https://hess.copernicus.org/articles/25/6223/2021/hess-25-6223-2021.pdf
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author E. Patault
V. Landemaine
J. Ledun
A. Soulignac
M. Fournier
J.-F. Ouvry
O. Cerdan
B. Laignel
author_facet E. Patault
V. Landemaine
J. Ledun
A. Soulignac
M. Fournier
J.-F. Ouvry
O. Cerdan
B. Laignel
author_sort E. Patault
collection DOAJ
description <p>Excessive sediment discharge in karstic regions can be highly disruptive to water treatment plants. It is essential for catchment stakeholders and drinking water suppliers to limit the impact of high sediment loads on potable water supply, but their strategic choices must be based on simulations integrating surface and groundwater transfers and taking into account possible changes in land use. Karstic environments are particularly challenging as they face a lack of accurate physical descriptions for the modelling process, and they can be particularly complex to predict due to the non-linearity of the processes generating sediment discharge. The aim of the study was to assess the sediment discharge variability at a water treatment plant according to multiple realistic land use scenarios. To reach that goal, we developed a new cascade modelling approach with an erosion-runoff geographic information system (GIS) model (WaterSed) and a deep neural network. The model was used in the Radicatel hydrogeological catchment (106 km<span class="inline-formula"><sup>2</sup></span> in Normandy, France), where karstic spring water is extracted to a water treatment plant. The sediment discharge was simulated for five design storms under current land use and compared to four land use scenarios (baseline, ploughing up of grassland, eco-engineering, best farming practices, and coupling of eco-engineering/best farming practices). Daily rainfall time series and WaterSed modelling outputs extracted at connected sinkholes (positive dye tracing) were used as input data for the deep neural network model. The model structure was found by a classical trial-and-error procedure, and the model was trained on 2 significant hydrologic years. Evaluation on a test set showed a good performance of the model (NSE <span class="inline-formula">=</span> 0.82), and the application of a monthly backward-chaining nested cross-validation revealed that the model is able to generalize on new datasets. Simulations made for the four land use scenarios suggested that ploughing up 33 % of grasslands would increase sediment discharge at the water treatment plant by 5 % on average. By contrast, eco-engineering and best farming practices will significantly reduce sediment discharge at the water treatment plant (respectively in the ranges of 10 %–44 % and 24 %–61 %). The coupling of these two strategies is the most efficient since it affects the hydro-sedimentary production and transfer processes (decreasing sediment discharge from 40 % to 80 %). The cascade modelling approach developed in this study offers interesting opportunities for sediment discharge prediction at karstic springs or water treatment plants under multiple land use scenarios. It also provides robust decision-making tools for land use planning and drinking water suppliers.</p>
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spelling doaj.art-8540296d2ab9447cbbf846245b42cea92022-12-21T23:41:11ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382021-12-01256223623810.5194/hess-25-6223-2021Simulating sediment discharge at water treatment plants under different land use scenarios using cascade modelling with an expert-based erosion-runoff model and a deep neural networkE. Patault0V. Landemaine1J. Ledun2A. Soulignac3M. Fournier4J.-F. Ouvry5O. Cerdan6B. Laignel7Normandie UNIV, UNIROUEN, UNICAEN, CNRS, M2C, FED-SCALE, Rouen, FranceBRGM, 3 avenue Claude Guillemin, BP6009, 45060 Orléans CEDEX 2, FranceAREAS, 2 avenue Foch, 76460 Saint-Valéry-en-Caux, FranceBRGM, 1039 rue de Pinville, 34000 Montpellier, FranceNormandie UNIV, UNIROUEN, UNICAEN, CNRS, M2C, FED-SCALE, Rouen, FranceAREAS, 2 avenue Foch, 76460 Saint-Valéry-en-Caux, FranceBRGM, 3 avenue Claude Guillemin, BP6009, 45060 Orléans CEDEX 2, FranceNormandie UNIV, UNIROUEN, UNICAEN, CNRS, M2C, FED-SCALE, Rouen, France<p>Excessive sediment discharge in karstic regions can be highly disruptive to water treatment plants. It is essential for catchment stakeholders and drinking water suppliers to limit the impact of high sediment loads on potable water supply, but their strategic choices must be based on simulations integrating surface and groundwater transfers and taking into account possible changes in land use. Karstic environments are particularly challenging as they face a lack of accurate physical descriptions for the modelling process, and they can be particularly complex to predict due to the non-linearity of the processes generating sediment discharge. The aim of the study was to assess the sediment discharge variability at a water treatment plant according to multiple realistic land use scenarios. To reach that goal, we developed a new cascade modelling approach with an erosion-runoff geographic information system (GIS) model (WaterSed) and a deep neural network. The model was used in the Radicatel hydrogeological catchment (106 km<span class="inline-formula"><sup>2</sup></span> in Normandy, France), where karstic spring water is extracted to a water treatment plant. The sediment discharge was simulated for five design storms under current land use and compared to four land use scenarios (baseline, ploughing up of grassland, eco-engineering, best farming practices, and coupling of eco-engineering/best farming practices). Daily rainfall time series and WaterSed modelling outputs extracted at connected sinkholes (positive dye tracing) were used as input data for the deep neural network model. The model structure was found by a classical trial-and-error procedure, and the model was trained on 2 significant hydrologic years. Evaluation on a test set showed a good performance of the model (NSE <span class="inline-formula">=</span> 0.82), and the application of a monthly backward-chaining nested cross-validation revealed that the model is able to generalize on new datasets. Simulations made for the four land use scenarios suggested that ploughing up 33 % of grasslands would increase sediment discharge at the water treatment plant by 5 % on average. By contrast, eco-engineering and best farming practices will significantly reduce sediment discharge at the water treatment plant (respectively in the ranges of 10 %–44 % and 24 %–61 %). The coupling of these two strategies is the most efficient since it affects the hydro-sedimentary production and transfer processes (decreasing sediment discharge from 40 % to 80 %). The cascade modelling approach developed in this study offers interesting opportunities for sediment discharge prediction at karstic springs or water treatment plants under multiple land use scenarios. It also provides robust decision-making tools for land use planning and drinking water suppliers.</p>https://hess.copernicus.org/articles/25/6223/2021/hess-25-6223-2021.pdf
spellingShingle E. Patault
V. Landemaine
J. Ledun
A. Soulignac
M. Fournier
J.-F. Ouvry
O. Cerdan
B. Laignel
Simulating sediment discharge at water treatment plants under different land use scenarios using cascade modelling with an expert-based erosion-runoff model and a deep neural network
Hydrology and Earth System Sciences
title Simulating sediment discharge at water treatment plants under different land use scenarios using cascade modelling with an expert-based erosion-runoff model and a deep neural network
title_full Simulating sediment discharge at water treatment plants under different land use scenarios using cascade modelling with an expert-based erosion-runoff model and a deep neural network
title_fullStr Simulating sediment discharge at water treatment plants under different land use scenarios using cascade modelling with an expert-based erosion-runoff model and a deep neural network
title_full_unstemmed Simulating sediment discharge at water treatment plants under different land use scenarios using cascade modelling with an expert-based erosion-runoff model and a deep neural network
title_short Simulating sediment discharge at water treatment plants under different land use scenarios using cascade modelling with an expert-based erosion-runoff model and a deep neural network
title_sort simulating sediment discharge at water treatment plants under different land use scenarios using cascade modelling with an expert based erosion runoff model and a deep neural network
url https://hess.copernicus.org/articles/25/6223/2021/hess-25-6223-2021.pdf
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