La contribution des eaux souterraines aux crues exceptionnelles de la Somme en 2001 Observations, hypothèses, modélisation

Pointet, Thierry; Amraoui, Nadia; Golaz, Catherine; Mardhel, Vincent; Négrel, Philippe; Pennequin, Didier; Pinault, Jean-Louis

doi:10.1051/lhb/2003120

Cited by 12 publications

(3 citation statements)

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“…Gardenia is a conceptual model that has already demonstrated its effectiveness in simulating and forecasting river flows and groundwater levels for watersheds of different sizes over varying periods of time [54][55][56][57]. It simulates the main mechanisms of the water cycle, precipitation (P), actual evapotranspiration (ETa), runoff (R), and groundwater recharge (GWR), using simplified physical laws which are translated into flows through a succession of reservoirs (Figure 2, [49]).…”

Section: Description Of the Hydrological Model Gardeniamentioning

confidence: 99%

Combined Impacts of Climate Change and Water Withdrawals on the Water Balance at the Watershed Scale—The Case of the Allier Alluvial Hydrosystem (France)

et al. 2023

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The Allier River and its alluvial aquifer constitute a shallow but highly productive water resource due to their hydrodynamic properties. This hydrosystem provides almost all of the water requirements for domestic supply and irrigation. Recent dry summers (such as those in 2015, 2019, and 2022) and the lack of winter recharge have led managers to question the sustainability of this resource. We proposed the use of hydrological modelling with Gardenia with which the water balance can be determined at the watershed scale (7020 km2) and with which forecasting simulations can be performed for 2030–2070. Thus, this work was divided into (1) model calibration (2000–2020), (2) the determination of the main drivers of the water balance (2000–2020), (3) and river flow and groundwater level simulation (2030–2070). For the latter, Gardenia was used considering a “better case”, using the RCM Aladin63 in RCP2.6, and considering a “worst case”, using the RCM RegCM4-6 in RCP8.5. The calibration for 2000–2014 showed good reproducibility of river flows (NSE = 0.91) and groundwater levels (NSE = 0.85). The model showed that the major drivers in 2000–2020 were actual evapotranspiration and effective precipitation, which, respectively, represented 68% and 32% of mean annual precipitation. Water withdrawals did not significantly contribute to the water balance with the exception of those in very dry summers, such as those in 2003, 2005, 2015, and 2019. Climate appeared, therefore, as a prevalent factor of the Allier hydrosystem functioning compared to global withdrawals except for that during these dry years. Prospective simulations showed a decline in annual river flows and groundwater levels by a maximum of −15% and −0.08 m asl (“worst case”), respectively. These simulations showed that the Allier hydrosystem will be able to meet the water needs for various uses until 2070. In detail, it is likely that summer shortages will no longer be compensated by the Naussac Dam if the hydrosystem faces more than two years of drought. In this case, water-saving solutions will have to be found. This study is, thus, a good example of the application of hydrological modelling to address management issues in such a hydrosystem.

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Section: Description Of the Hydrological Model Gardeniamentioning

confidence: 99%

Combined Impacts of Climate Change and Water Withdrawals on the Water Balance at the Watershed Scale—The Case of the Allier Alluvial Hydrosystem (France)

et al. 2023

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“…Flood events can even be caused by a rapid increase of water table levels in aquifers, which is known as groundwater flooding [Abboud et al, 2018]. The flood event in the Somme basin in 2000-2001 was concomitant to a rise in the groundwater table of more than 10 m [Pointet et al, 2003], with a large part of flood water carrying the isotopic signature of the chalk aquifer [Négrel and Petelet-Giraud, 2005].…”

Section: Introductionmentioning

confidence: 99%

An underground view of surface hydrology: what can piezometers tell us about river floods and droughts?

Pelletier¹,

Andréassian²

2024

Comptes Rendus. Géoscience

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“…These floodings were the result of above-average winter rainfall during several years rising GWL in the chalkwith limited summer recession of GWLand an exceptional previous winter with strong precipitation leading to rapidly increase levels of 10m generating the disastrous floodings (Deneux and Martin, 2001;Habets et al, 2010). This 2001 event arised from both a low-frequency variability (LFV) with a slow increase of GWL during several years and a high-frequency variability that is superimposed, with a sudden rise of GWL during the 2000-2001 winter (Pointet et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Influence of low-frequency variability on high and low groundwater levels: example of aquifers in Paris Basin

Baulon

Masséi

Allier

et al. 2022

Preprint

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Abstract. Groundwater levels (GWL) very often fluctuate over a wide range of timescales (infra-annual, annual, multi-annual, decadal). In many instances, aquifers act as low-pass filters, dampening the high-frequency variability and amplifying low-frequency variations (from multi-annual to decadal timescales) which basically originate from large-scale climate variability. In the aim of better understanding and ultimately anticipating groundwater droughts and floods, it appears crucial to evaluate whether (and how much) the very high or very low GWLs are sensitive to such low-frequency variability (LFV), which was the main objective of the study presented here. As an example, we focused on exceedance and non-exceedance of the 80 % and 20 % GWL percentiles respectively, in the Paris Basin aquifers over the 1976–2019 period. GWL time series were extracted from a database consisting of relatively undisturbed GWL time series regarding anthropogenic influence (water abstraction by either continuous or periodic pumping) over Metropolitan France. Based on this dataset, our approach consisted of exploring the effect of GWL low-frequency components on threshold exceedance and non-exceedance by successively filtering out low-frequency components of GWL signals using maximum overlap discrete wavelet transform (MODWT). Multi-annual (~7-yr) and decadal (~17-yr) variabilities were found to be the predominant LFVs in GWL signals, in accordance with previous studies in the northern France area. Filtering out these components (either independently or jointly) to (i) examine the proportion of high level (HL) and low level (LL) occurrences generated by these variabilities, (ii) estimate the contribution of each of these variabilities in explaining the occurrence of major historical events associated to well-recognized societal impacts. A typology of GWL variations in Paris Basin aquifers was first determined by quantifying the variance distribution across timescales. Four GWL variation types could be found according to the predominance of annual, multi-annual or/and decadal variabilities in these signals: decadal dominant (type iD), multi-annual and decadal dominant (type iMD), annual dominant (type cA), annual and multi-annual dominant (type cAM). We observed a clear dependence of high and low GWL to LFV for aquifers exhibiting these four GWL variation types. In addition, the respective contribution of multi-annual and decadal variabilities in the threshold exceedance varied according to the event. In numerous aquifers, it also appeared that the sensitivity to LFV was higher for LL than HL. A similar analysis was conducted on the only available long-term GWL time series which covered a hundred years. This allowed us to highlight a potential influence of multidecadal variability on HL and LL too. This study underlined the key role of LFV in the occurrence of HL and LL. Since LFV originates from large-scale stochastic climate variability as demonstrated in many previous studies in the Paris Basin or nearby regions, our results point out that i) poor representation of LFV in General Circulation Models (GCM) outputs used afterwards for developing hydrological projections can result in strong uncertainty in the assessment of future groundwater extremes (GWE), ii) potential changes in the amplitude of LFV, be they natural or induced by global climate change, may lead to substantial changes in the occurrence and severity of GWE for the next decades. Finally, this study also stresses the fact that due to the stochastic nature of LFV, no deterministic prediction of future GWE for the mid- or long term horizons can be achieved even though LFV may look periodic.

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La contribution des eaux souterraines aux crues exceptionnelles de la Somme en 2001 Observations, hypothèses, modélisation

Cited by 12 publications

References 0 publications

Combined Impacts of Climate Change and Water Withdrawals on the Water Balance at the Watershed Scale—The Case of the Allier Alluvial Hydrosystem (France)

Combined Impacts of Climate Change and Water Withdrawals on the Water Balance at the Watershed Scale—The Case of the Allier Alluvial Hydrosystem (France)

An underground view of surface hydrology: what can piezometers tell us about river floods and droughts?

Influence of low-frequency variability on high and low groundwater levels: example of aquifers in Paris Basin

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