Deep learning shows declining groundwater levels in Germany until 2100 due to climate change

Abstract

In this study we investigate how climate change will directly influence the groundwater resources in Germany during the 21st century. We apply a machine learning groundwater level prediction approach based on convolutional neural networks to 118 sites well distributed over Germany to assess the groundwater level development under different RCP scenarios (2.6, 4.5, 8.5). We consider only direct meteorological inputs, while highly uncertain anthropogenic factors such as groundwater extractions are excluded. While less pronounced and fewer significant trends can be found under RCP2.6 and RCP4.5, we detect significantly declining trends of groundwater levels for most of the sites under RCP8.5, revealing a spatial pattern of stronger decreases, especially in the northern and eastern part of Germany, emphasizing already existing decreasing trends in these regions. We can further show an increased variability and longer periods of low groundwater levels during the annual cycle towards the end of the century.

Using stable water isotopes to understand ecohydrological partitioning under contrasting land uses in a drought‐sensitive rural, lowland catchment

“…For example, even the large precipitation event in June was not able to refill the soil moisture deficits at all sites, particularly under forests. The precipitation patterns we observed in 2021 at the DMC fit findings of shifting precipitation events (more rain during winter and less in summer) as well as more extreme events (large precipitation events followed by prolonged droughts) due to climate change (Wunsch et al, 2022).…”

“…For example, the 2018 drought in central and northern Europe caused severe impacts through crop failure and water stress in forests (Brás et al, 2021;Senf & Seidl, 2021;Smith, Tetzlaff, Kleine, et al, 2020b). As droughts tend to effect blue water fluxes more strongly than green water fluxes (see Orth & Destouni, 2018), groundwater levels can take much longer to recover to reduced recharge (Smith et al, 2021;Wunsch et al, 2022). Therefore, an improved understanding of ecohydrological fluxes and water partitioning under different land use in drought-sensitive landscapes is urgently required to understand how to best sustain important anthropogenically (e.g., freshwater, food, fibre, and shelter) and naturally (e.g., forests, wetlands, and streams) relevant ecosystem services (see Foley et al, 2005).…”

GIS-AHP Ensembles for Multi-Actor Multi-Criteria Site Selection Processes: Application to Groundwater Management under Climate Change

“…Coherently, the anticipated impacts of climate change in Germany for the period 2020 to 2050 include drier and hotter summers, as well as a seasonal increase in water demand and daily demand peaks [7][8][9][10][11][12][13]. Since the vast majority of water demand in Germany is covered by groundwater, a seasonal increase in water demand could force additional groundwater abstractions and inflict elevated stress on heavily exploited groundwater bodies in summer periods [14,15]. This mechanism will likely cause an increase in groundwater level fluctuation and maximum drawdown, despite eventually unchanged long-term average groundwater levels [7,9,[14][15][16][17].…”

“…Since the vast majority of water demand in Germany is covered by groundwater, a seasonal increase in water demand could force additional groundwater abstractions and inflict elevated stress on heavily exploited groundwater bodies in summer periods [14,15]. This mechanism will likely cause an increase in groundwater level fluctuation and maximum drawdown, despite eventually unchanged long-term average groundwater levels [7,9,[14][15][16][17]. Such an increase in groundwater level fluctuations could, in turn, have adverse effects on groundwater-dependent ecosystems, baseflow discharge, rain-fed agriculture, and forestry in areas with shallow groundwater tables.…”

“…groundwater level fluctuation and maximum drawdown, despite eventually unchanged long-term average groundwater levels [7,9,[14][15][16][17]. Such an increase in groundwater level fluctuations could, in turn, have adverse effects on groundwater-dependent ecosystems, baseflow discharge, rain-fed agriculture, and forestry in areas with shallow groundwater tables.…”