Exploring the Critical Zone Heterogeneity and the Hydrological Diversity Using an Integrated Ecohydrological Model in Three Contrasted Long‐Term Observatories

Abstract

An integrated ecohydrological modeling approach was deployed in three long‐term critical zone (CZ) observatories of the French CZ network (CZ Observatories—Application and Research) to better understand how the CZ heterogeneity modulates the water cycle within territories. Ecohydrological simulations with the physically based model EcH2O‐iso constrained by a wide range of observations crossing several disciplines (meteorology, hydrology, geomorphology, geophysics, soil sciences, and satellite imagery) are able to capture stream water discharges, evapotranspiration fluxes, and piezometric levels in the Naizin, Auradé, and Strengbach watersheds. In Naizin, an agricultural watershed in northwestern France with a schist bedrock underlying deep weathered materials (5–15 m) along gentle slopes, modeling results reveal a deep aquifer with a large total water storage (1,080–1,150 mm), an important fraction of inactive water storage (94%), and relatively long stream water transit times (0.5–2.5 years). In the Auradé watershed, representative of agricultural landscapes of the southwestern France developed on molasse, a relatively shallow regolith (1–8 m) is observed along hilly slopes. Simulations indicate a shallow aquifer with moderate total water storage (590–630 mm), an important fraction of inactive water storage (91%), and shorter stream water transit times (0.1–1.3 years). In the Strengbach watershed, typical of mid‐mountain forested landscapes developed on granite, CZ evolution implies a shallow regolith (1–5 m) along steep slopes. Modeling results infer a shallow aquifer with the smallest total water storage (475–575 mm), the shortest stream water transit times (0.1–0.7 years), but also the highest fraction of active water storage (18%).

Improving calibration of groundwater flow models using headwater streamflow intermittence

“…These results follow previous studies showing the role of modelled groundwater dynamics on streamflow (Carlier et al, 2018a;Gascuel-Odoux et al, 2010). Although the literature emphasizes that stream networks are dynamic in a wide range of topographic, geologic and climatic contexts, our findings support the hypothesis derived from field surveys that specifically highlight the influence of the subsurface (Ackerer et al, 2023;Belemtougri et al, 2021;Godsey & Kirchner, 2014;Hatley et al, 2023;Lapides et al, 2021;Prancevic & Kirchner, 2019;Warix et al, 2023;Zimmer & McGlynn, 2017b). Authors generally identify transmissivity and subsurface storage capacity, as key factors in streamflow intermittence processes.…”

Coupled DSSAT and HYDRUS-1D Simulation of the Farmland–Crop Water Cycling Process in the Dengkouyangshui Irrigation District

“…Therefore, investigating water cycling processes within the Dengkouyangshui irrigation district is highly important for enhancing irrigation water use efficiency and boosting crop yields. The water cycle serves as the crucial link connecting various terrestrial systems, such as the hydrosphere, atmosphere, lithosphere, and biosphere [2] Hydrological models [3][4][5][6] have proven to be effective tools for exploring the complex mechanisms of water cycling in irrigation districts and are indispensable in research related to water resource management and the impact of human productive activities on the water cycle [7]. Numerous scholars have carried out both experimental and numerical simulation studies on the water cycle in irrigation areas [8][9][10]; however, these investigations tend to be expensive and time-consuming, and the outcomes are often specific to each study.…”