Investigation of soil water hydrological process in the permafrost active layer using stable isotopes

The stable isotopes (δD and δ18O) in soil water allow tracing of the flow and transportation of water in the soil. However, there are few studies on the use of soil water stable isotopes to explore the soil water in the floodplain, especially in determining the soil water source and infiltration mechanism. The Bayesian mixing model (MixSIAR) was integrated with the line conditioned excess (lc-excess) of stable isotopes (δD and δ18O) in precipitation, soil water (0–150 cm), river water, and groundwater to determinate the source and recharge mechanisms of two different soil profile types in the floodplain of the upper Yellow River in Lanzhou, China. The results showed that soil water below 80 cm was affected by river water recharge, affecting soil water content and stable isotopic composition at S1 sampling points (profile parallel to river water); this effect was not observed at S2 (profile is higher than the river water) sampling points. The isotopic compositions of the soil water sources at the two sampling points (S1: δD = −77.41‰, δ18O = −11.01‰; S2: δD = −74.02‰, δ18O = −10.56‰) were depleted more than those in the long-term amount-weighted precipitation isotopes (δD = −56.30‰, δ18O = −8.17‰). The isotope signatures of soil water sources are similar to the isotope characteristics of some high-intensity precipitation events (≥30 mm/day), indicating that soil water originates from a fraction of the total precipitation. The piston flow (60%) and the preferential flow (40%) coexist, but soil moisture and rainfall intensity will affect the sequence of the two infiltration methods. This study provides insights for understanding the hydrological process of the upper Yellow River and evaluating groundwater quality and protecting the floodplain environment.

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Spatiotemporal variations of soil water stable isotopes in a small karst sinkhole basin

Environmental Earth Sciences ◽

10.1007/s12665-020-09284-w ◽

2021 ◽

Vol 80 (1) ◽

Author(s):

Tao Zhang ◽

Jianhong Li ◽

Junbing Pu ◽

Weijie Huo ◽

Sainan Wang

Keyword(s):

Stable Isotopes ◽

Soil Water ◽

Spatiotemporal Variations ◽

Karst Sinkhole

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Characterization of hydraulic properties in the upper vadose zone for two aquifers in Slovenia

10.5194/egusphere-egu21-2407 ◽

2021 ◽

Author(s):

Vesna Zupanc ◽

Matjaž Glavan ◽

Miha Curk ◽

Urša Pečan ◽

Michael Stockinger ◽

...

Keyword(s):

Stable Isotopes ◽

Soil Water ◽

Water Flow ◽

Vadose Zone ◽

Hydraulic Properties ◽

Isotope Composition ◽

Transport Processes ◽

Precipitation Event ◽

Water Fluxes ◽

Flow And Transport

Environmental tracers, present in the environment and provided by nature, provide integrative information about both water flow and transport. For studying water flow and solute transport, the hydrogen and oxygen isotopes are of special interest, as their ratios provide a tracer signal with every precipitation event and are seasonally distributed. In order to follow the seasonal distribution of stable isotopes in the soil water and use this information for identifying hydrological processes and hydraulic properties, soil was sampled three times in three profiles, two on Kr&#353;ko polje aquifer in SE Slovenia and one on Ljubljansko polje in central Slovenia. Isotope composition of soil water was measured with the water-vapor-equilibration method. Based on the isotope composition of soil water integrative information about water flow and transport processes with time and depth below ground were assessed. Porewater isotopes were in similar range as precipitation for all three profiles. &#160;Variable isotope ratios in the upper 60 cm for the different sampling times indicated dynamic water fluxes in this upper part of the vadose zone. Results also showed more evaporation at one sampling location, Brege. The information from stable isotopes will be of importance for further analyzing the water fluxes in the vadose zone of the study sties.&#160; This research was financed by the ARRS BIAT 20-21-32 and IAEA CRP 1.50.18 Multiple isotope fingerprints to identify sources and transport of agro-contaminants. &#160;

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Employing stable isotopes to determine the residence times of soil water and the temporal origin of water taken up by Fagus sylvatica and Picea abies in a temperate forest

New Phytologist ◽

10.1111/nph.15255 ◽

2018 ◽

Vol 219 (4) ◽

pp. 1300-1313 ◽

Cited By ~ 29

Author(s):

Nadine Brinkmann ◽

Stefan Seeger ◽

Markus Weiler ◽

Nina Buchmann ◽

Werner Eugster ◽

...

Keyword(s):

Stable Isotopes ◽

Picea Abies ◽

Soil Water ◽

Fagus Sylvatica ◽

Temperate Forest ◽

Residence Times

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Partitioning daily evapotranspiration from a marsh wetland using stable isotopes in a semiarid region

Hydrology Research ◽

10.2166/nh.2017.005 ◽

2017 ◽

Vol 49 (4) ◽

pp. 1005-1015 ◽

Cited By ~ 2

Author(s):

Jing Zhang ◽

Shichun Zhang ◽

Wenguang Zhang ◽

Bo Liu ◽

Chao Gong ◽

...

Keyword(s):

Stable Isotopes ◽

Steady State ◽

Wetland Management ◽

Management Strategies ◽

Theoretical Data ◽

Early Morning ◽

Semiarid Region ◽

Hydrological Process ◽

Leaf Transpiration ◽

Vegetation Indexes

Abstract The hydrological process of evapotranspiration (ET) plays an important role in water circulation in wetlands, and understanding the contributions of wetland ET to local and regional water cycles can help in designing effective wetland management strategies. In this paper, a numerical model, vegetation indexes, and stable isotopes were integrated to partition ET in the Momoge Wetland to understand hydrological processes and calculate the contribution of wetland ET to local hydrological cycling. The results of the non-steady state (NSS) model indicated clear deviation of leaf water enrichment (δLb) from an isotopic steady state (ISS) for Phragmites australis, and the model accuracy improved particularly in the early morning and evening when air moisture was highest during the day. The isotopic mass balance showed that E and T contributed approximately 62% and 38% to ET, respectively. Using the estimated proportion of T to ET, in combination for the measured leaf transpiration, total ET was estimated at approximately 8.76 mm d−1. Additionally, the amount of ET clearly changed on an hourly scale, with most primarily occurring at approximately noon. Based on comparison among internationally important wetlands distributed in northeast China, the results in this study are reasonable and will provide theoretical data for wetland water resources management.

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Identify the influencing paths of precipitation and soil water storage on runoff: an example from Xinjiang River Basin, Poyang Lake, China

Water Science & Technology Water Supply ◽

10.2166/ws.2017.224 ◽

2017 ◽

Vol 18 (5) ◽

pp. 1598-1605

Author(s):

Hongxiang Fan ◽

Ligang Xu ◽

Xiaolong Wang ◽

Yuexia Wu ◽

Jiahu Jiang

Keyword(s):

Soil Water ◽

River Basin ◽

Poyang Lake ◽

Water Storage ◽

Soil Water Storage ◽

Hydrological Process ◽

Analysis Method ◽

Runoff Generation ◽

The Past ◽

Total Influence

Abstract Runoff generation is a complex meteorological-hydrological process influenced by many factors. We analyzed the effects of changes in precipitation and soil water storage (SWS) on runoff generation using the path-analysis method (PAM) in Xinjiang River Basin (XJRB). By using multiple trend analysis we found that precipitation, SWS and runoff in XJRB fluctuated throughout the past 30 years with no monotonic trends at both annual and seasonal scales. Further analysis demonstrated that runoff is more sensitive to precipitation than to SWS in XJRB. PAM results showed that direct influence of precipitation on runoff was seven times as large as that of SWS. Moreover, the indirect influence of precipitation on runoff through SWS accounts for 11–31% of the total influence of precipitation on runoff. This information will improve the description of precipitation and runoff relationship as well as the planning and management of water resources.

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Diurnal pattern of the drying front in the desert and its application for determining the effective infiltration

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-6-1021-2009 ◽

2009 ◽

Vol 6 (1) ◽

pp. 1021-1054 ◽

Cited By ~ 1

Author(s):

Y. Zeng ◽

Z. Su ◽

L. Wan ◽

Z. Yang ◽

T. Zhang ◽

...

Keyword(s):

Soil Water ◽

Vadose Zone ◽

Inner Mongolia ◽

Rainfall Event ◽

Balance Model ◽

Physical Parameters ◽

Badain Jaran Desert ◽

Hydrological Process ◽

Diurnal Pattern ◽

Variation Pattern

Abstract. Located in western Inner Mongolia, the Badain Jaran Desert is the second largest desert in China and consists of a regular series of stable megadunes, among which over 70 permanent lakes exist. The unexpected lakes in desert attracted research interests on exploring the hydrological process under this particular landscape; however, a very few literatures exist on the diurnal and spatial variation of the drying front in this area, which is the main issue in the desert hydrological process to characterize the movement of water in soil. In order to understand the drying front in the Badain Jaran Desert, a field campaign was conducted by the observations of soil physical parameters and micrometeorological parameters. With the field data, the performance of a vadose zone soil water balance model, the HYDRUS, was verified and calibrated. Then, the HYDRUS was used to produce the spatial and temporal information of coupled water, water vapour and heat transport in sand to characterize the variation pattern of the drying front before, during and after the rainfall. Finally, the deepest drying front was applied to determine the effective infiltration, which is defined as the amount of soil water captured by the sand beneath the deepest drying front by infiltrating water of an incident rainfall event.

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The Soil Water Evaporation Process from Mountains Based on the Stable Isotope Composition in a Headwater Basin and Northwest China

Water ◽

10.3390/w12102711 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2711 ◽

Cited By ~ 1

Author(s):

Leilei Yong ◽

Guofeng Zhu ◽

Qiaozhuo Wan ◽

Yuanxiao Xu ◽

Zhuanxia Zhang ◽

...

Keyword(s):

Soil Water ◽

Environmental Remediation ◽

Isotope Composition ◽

Salt Content ◽

Water Isotopes ◽

Water Evaporation ◽

Hydrological Process ◽

Arid Areas ◽

Time Dynamics ◽

Evaporation Loss

Soil water is a link between different water bodies. The study of soil water evaporation is of great significance to understand the regional hydrological process, promote environmental remediation in arid areas, and rationalize ecological water use. On the basis of soil water δ2H and δ18O data from April to October 2017 in the Xiying River basin in the upper reaches of the Qilian mountains, the lc-excess and Craig-Gordon model were applied to reflect the evaporating fractionation of soil water. The results show that the change in evaporation loss drives the enrichment of soil water isotopes. The signal of evaporative fractionation of soil water isotopes at different elevations has spatiotemporal heterogeneity. From the perspective of time dynamics, the evaporation loss of the whole region during the observation period was affected by temperature before July, while after July, it was controlled jointly by temperature and humidity, evaporation was weakened. Soil salt content and vegetation played an important role in evaporation loss. In terms of spatial dynamics, the soil moisture evaporation at the Xiying (2097 m) and Huajian (2390 m) stations in the foothills area is larger than that at the Nichan station (2721 m) on the hillside and Lenglong station (3637 m) on the mountain top. The surface soil water evaporation is strong, and the evaporation becomes weak with the increase of depth. The research has guiding significance for the restoration and protection of vegetation in arid areas and the formulation of reasonable animal husbandry policies.

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Simulating soil-plant-atmosphere interactions for sub-daily in situ observations of stable isotopes in soil and xylem water to assess two-pore domain model hypothesis

10.5194/egusphere-egu2020-17975 ◽

2020 ◽

Author(s):

Fabian Bernhard ◽

Stefan Seeger ◽

Markus Weiler ◽

Arthur Gessler ◽

Katrin Meusburger

Keyword(s):

Stable Isotopes ◽

Soil Water ◽

Vadose Zone ◽

Model Performance ◽

Root Water Uptake ◽

In Situ Observations ◽

Pore Domain ◽

Model Structures ◽

Isotope Measurements

Recent advances in stable isotope measurements within the soil-plant-atmosphere continuum have paved the way to high-resolution sub-daily observations of plant water supply (Stumpp et al. 2018, Volkmann et al. 2016a, 2016b). It seems time is ripe for in-depth assessments of long-standing yet much-debated assumptions such as complete, homogenous mixing of water in the vadose zone (&#8220;one water world&#8221; versus "two water world") or absence of fractionation during root water uptake and vascular transport in plants.Information on the nature of these processes contained in high-resolution data sets needs to be exploited. One way to test hypotheses and thereby advance our understanding of soil-plant water interactions is by analysing observations with numerical simulations of the system dynamics &#8211; a method also known as inverse modelling. By evaluating the model performance and parameter identifiability of different model structures, conclusions can be drawn regarding the relevance of the modelled processes for reproduction of the observations. Testing two different models allows thus to assess the impact of the difference.We develop a framework for numerical simulation and model-based analysis of observations from soil-plant-atmosphere systems with a focus on isotopic fractionation. A central objective is to facilitate the evaluation of different model structures and thus test model hypotheses. This can assist development of models specifically tailored to the intended purpose and available data. The framework will first be tested with the "SWIS" model presented by Sprenger et al. (2018).As an illustration of the framework, we will test the model performance on a dataset of continuous, in situ observations of stable isotopes in xylem water of beech trees and soil water in four depths combined with observations of soil water content. The model assumes one-dimensional soil water flow taking place in one or two separate flow domains for tightly and weakly bound pore water. These two water pools are separated by a matrix potential threshold and isotopic exchange is modelled only through the vapour phase. Root water uptake is parametrised using the Feddes-Jarvis model. First results allow to assess the relevance of the two-pore domain hypothesis for the different soil depths and xylem water.&#160;Sprenger, M., D. Tetzlaff, J. Buttle, H. Laudon, H. Leistert, C.P.J. Mitchell, J. Snelgrove, M. Weiler, and C. Soulsby. 2018. Measuring and modeling stable isotopes of mobile and bulk soil water. Vadose Zone J. 17:170149. doi:10.2136/vzj2017.08.0149Stumpp, C., N. Br&#252;ggemann, and L. Wingate. 2018. Stable isotope approaches in vadose zone research. Vadose Zone J. 17:180096. Doi: 10.2136/vzj2018.05.0096Volkmann, T.H., K. Haberer, A. Gessler, and M. Weiler. 2016a. High&#8208;resolution isotope measurements resolve rapid ecohydrological dynamics at the soil&#8211;plant interface. New Phytologist, 210(3), 839-849.Volkmann, T.H., K. Haberer, A. Gessler, and M. Weiler. 2016a. High&#8208;resolution isotope measurements resolve rapid ecohydrological dynamics at the soil&#8211;plant interface. New Phytologist, 210(3), 839-849.

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