scholarly journals Isotopic analysis of water cycle elements in different land covers in a small headwater watershed

Water Policy ◽  
2017 ◽  
Vol 19 (3) ◽  
pp. 574-585 ◽  
Author(s):  
Si-min Qu ◽  
Shuai Shan ◽  
Xi Chen ◽  
Min-min Zhou ◽  
Han Liu
Keyword(s):  
Surface Water ◽  
Isotopic Composition ◽  
Temporal Variation ◽  
Water Cycle ◽  
Isotopic Analysis ◽  
Base Flow ◽  
Land Uses ◽  
Hydrograph Separation ◽  
Isotopic Variation ◽  
Variation Range

In this study, comparisons of isotopic variation of rainfall, throughfall, surface water, and groundwater were conducted in the Meilin watershed, which represents two different land uses, chestnut wood and bamboo. Also, isotopic differences between rainfall and throughfall were identified in these sub-watersheds. The results showed that the isotopic value of incremental rainfall, incremental throughfall and surface water exhibited a marked temporal variation in the selected sub-watersheds. The throughfall isotopic variation range was smaller than that of rainfall, which may result from the different production process between rainfall and throughfall. However, the isotopic composition difference between rainfall and throughfall resulting from different land uses was insignificant. The range of isotopic composition variation of surface water was not the same as that of rainfall, indicating that surface water came from a mix of precipitation and water stored before the rainfall event. The temporal variation of the isotopic composition of groundwater was small, implying that the influence of different land uses on groundwater isotopic composition was insignificant. The total variation range of δ2H and δ18O of groundwater was smaller than that of surface water and sequential incremental rainfall, which means the δ18O of groundwater can be replaced by that of base flow before the event in the hydrograph separation.

scholarly journals Spatially-Resolved Integrated Precipitation-Surface-Groundwater Water Isotope Mapping From Crowd Sourcing: Toward Understanding Water Cycling Across a Post-glacial Landscape

2021 ◽  
Vol 3 ◽  
Author(s):  
Alison Cole ◽  
David F. Boutt
Keyword(s):  
Surface Water ◽  
Isotopic Composition ◽  
Summer Precipitation ◽  
Isotopic Analysis ◽  
Resource Assessment ◽  
Hydrologic Cycle ◽  
Crowd Sourcing ◽  
Large Spatial Scale ◽  
Vapor Source ◽  
Isotopic Analyses

Isotopic analyses of δ18O and δ2H of water in the context of the hydrologic cycle have allowed hydrologists to better understand the portioning of water between the different water domains. Isoscapes on a large spatial scale have been created to show isotopic variation in waters as a function of elevation, temperature, distance to coast, and water vapor source. We present the spatial and temporal isotopic results of precipitation, surface water, and groundwater of an ongoing study across Massachusetts, USA in order to establish an isotopic baseline for the region. This represents one of the most comprehensive and detailed isotopic studies of water across a 10,000 sq mi area that has exhaustively sampled important components of the terrestrial hydrologic cycle (precipitation, groundwater, and surface waters). We leverage the support of volunteers and citizen scientists to crowd source samples for isotopic analysis. The database consists of water samples from 14 precipitation sites, 409 ground water sites and 516 surface water sites across the state of Massachusetts, USA. The results indicate that groundwater isotopic composition ranges from δ18O −11 to −4‰ surface water ranges from δ18O −13 to −3.84‰ and precipitation ranges from δ18O −17.88 to −2.89‰. On a first order, the small bias of mean groundwater (−8.7‰) and surface water (−8.0‰) isotopes compared to precipitation δ18O (−7.6‰) supports that groundwater recharge and surface water storage effects through the hydrologic year impact the isotopic composition of surface and groundwater. While differences are distinct, they are larger than previously reported values, but still suggest more importance of summer precipitation than previously acknowledged. On average seasonal amplitudes of precipitation (2.7‰), surface water (1.13‰), and groundwater (~0‰) of the region demonstrate young water fractions of surface water to be 40% with groundwater ~0%. Results demonstrate that mean δ18O in precipitation, surface water and groundwaters are more enriched in heavy isotopes in areas near the coast, than the interior and western portion of Massachusetts. The hope is for this dataset to become an important tool for water management and water resource assessment across the region.

Stable isotope tracers as diagnostic tools in studying water sources in a humid bamboo watershed during the plum rainfall events

Water Policy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 368-381
Author(s):  
Jianfeng Gou ◽  
Simin Qu ◽  
Peng Shi ◽  
Dachen Li ◽  
Xueqiu Chen ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Temporal Variation ◽  
Soil Water ◽  
Meteoric Water ◽  
Water Sources ◽  
Rainfall Events ◽  
Water Line ◽  
Isotopic Variation ◽  
Meteoric Water Line

Abstract This study investigates the temporal variation of stable isotopic composition in precipitation, soil water, and streamflow water during the plum rainfall events in an upland headwater watershed which is mainly covered with bamboo. The results show that the isotopic composition of various water sources exhibit significant temporal variation. The local meteoric water line is established by using the relationship between the stable isotope of oxygen-18 and deuterium, which is slightly different from the meteoric water line of China. The isotopic temporal variation of precipitation is closely related to exchange effect between raindrops and environmental vapor, evaporation fractionation and rainfall intensity. The isotopic variation of shallow soil water is mainly determined by canopy interception, ground evaporation and the mixing with pre-event water; as for the isotopic variation of deep soil water, it is virtually influenced by pre-event water. The most enriched isotopic composition of streamflow and deuterium excess (d-excess) differences between streamflow and rainfall both indicate that streamflow is recharged not only by event water but also by pre-event water. Hence, a better understanding of precipitation formation and the hydrological response under the plum rainfall system may be instructive for the management of water resources in humid watersheds in southern China.

scholarly journals Stable H-O Isotopic Composition and Water Quality Assessment of Surface Water and Groundwater: A Case Study in the Dabie Mountains, Central China

2019 ◽  
Vol 16 (21) ◽  
pp. 4076 ◽  
Author(s):  
Kunhua Yang ◽  
Guilin Han ◽  
Chao Song ◽  
Peng Zhang
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Isotopic Composition ◽  
Water Cycle ◽  
Water Quality Assessment ◽  
Pond Water ◽  
Central China ◽  
Dabie Mountains ◽  
Reservoir Water ◽  
Surface Water And Groundwater

In order to understand the water cycle and assess the water quality for irrigation purposes in the Upper Pi River Basin (UPRB), which is the northern slope of the Dabie Mountains, 68 surface water and groundwater samples were collected and analyzed for H-O isotopes and hydrochemistry during the high-flow season in 2017 and 2018. The results show that ranges of hydrogen and oxygen isotopic composition (δ2H: −68.8‰ to −40.8‰, δ18O: −10.05‰ to −5.05‰) are controlled by the medium latitude and high altitude of the UPRB. Among different types of water, the δ2H and δ18O values can be ordered as follows: reservoir water < spring water ≈ river water < pond water. The water of the upstream medium and small reservoir is enriched with lighter isotopes that is likely related to more exchange with rainwater and less residence time; however, large reservoirs are similar to the upstream river and spring in terms of the H-O isotopic composition. Hydro-chemical facies are dominated by the Ca-HCO3 type in the UPRB, which reflects fresh recharged water from rainfall, and few samples are of the Ca-Cl type that is caused by intensive evaporation. The water quality for irrigation purposes was also evaluated. According to the Wilcox diagram, United States Salinity Laboratory (USSL) diagram, magnesium hazard, and Kelly’s ratio, all water samples have been considered suitable for irrigation water.

scholarly journals Estimating surface runoff and groundwater recharge in an urban catchment using a water balance approach

2021 ◽  
Vol 29 (7) ◽  
pp. 2411-2428
Author(s):  
Robin K. Weatherl ◽  
Maria J. Henao Salgado ◽  
Maximilian Ramgraber ◽  
Christian Moeck ◽  
Mario Schirmer
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Groundwater Recharge ◽  
Surface Runoff ◽  
Urban Areas ◽  
Water Cycle ◽  
Land Use Changes ◽  
Curve Number ◽  
Hydrograph Separation ◽  
Balance Approach

AbstractLand-use changes often have significant impact on the water cycle, including changing groundwater/surface-water interactions, modifying groundwater recharge zones, and increasing risk of contamination. Surface runoff in particular is significantly impacted by land cover. As surface runoff can act as a carrier for contaminants found at the surface, it is important to characterize runoff dynamics in anthropogenic environments. In this study, the relationship between surface runoff and groundwater recharge in urban areas is explored using a top-down water balance approach. Two empirical models were used to estimate runoff: (1) an updated, advanced method based on curve number, followed by (2) bivariate hydrograph separation. Modifications were added to each method in an attempt to better capture continuous soil-moisture processes and explicitly account for runoff from impervious surfaces. Differences between the resulting runoff estimates shed light on the complexity of the rainfall–runoff relationship, and highlight the importance of understanding soil-moisture dynamics and their control on hydro(geo)logical responses. These results were then used as input in a water balance to calculate groundwater recharge. Two approaches were used to assess the accuracy of these groundwater balance estimates: (1) comparison to calculations of groundwater recharge using the calibrated conceptual HBV Light model, and (2) comparison to groundwater recharge estimates from physically similar catchments in Switzerland that are found in the literature. In all cases, recharge is estimated at approximately 40–45% of annual precipitation. These conditions were found to closely echo those results from Swiss catchments of similar characteristics.

Isotopic composition analysis of dissolved mercury in seawater with purge and trap preconcentration and a modified Hg introduction device for MC-ICP-MS

2015 ◽  
Vol 30 (2) ◽  
pp. 353-359 ◽  
Author(s):  
Haiying Lin ◽  
Dongxing Yuan ◽  
Bingyan Lu ◽  
Shuyuan Huang ◽  
Lumin Sun ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Isotopic Analysis ◽  
Composition Analysis ◽  
Analysis Method ◽  
Purge And Trap ◽  
Icp Ms ◽  
Dissolved Mercury ◽  
Preconcentration Method

A modified introduction device and a preconcentration method were developed to enhance the sensitivity of the Hg isotopic analysis method.

scholarly journals An Optimized Snowmelt Lysimeter System for Monitoring Melt Rates and Collecting Samples for Stable Water Isotope Analysis

2019 ◽  
Vol 67 (1) ◽  
pp. 20-31 ◽  
Author(s):  
Andrea Rücker ◽  
Massimiliano Zappa ◽  
Stefan Boss ◽  
Jana von Freyberg
Keyword(s):  
Isotopic Composition ◽  
Isotope Analysis ◽  
Ground Level ◽  
Isotopic Signature ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Environmental Tracers ◽  
Hydrograph Separation ◽  
Stable Water Isotopes ◽  
Restricted Volume

Abstract The contribution of snow meltwater to catchment streamflow can be quantified through hydrograph separation analyses for which stable water isotopes (18O, 2H) are used as environmental tracers. For this, the spatial and temporal variability of the isotopic composition of meltwater needs to be captured by the sampling method. This study compares an optimized snowmelt lysimeter system and an unheated precipitation collector with focus on their ability to capture snowmelt rates and the isotopic composition of snowmelt. The snowmelt lysimeter system consists of three individual unenclosed lysimeters at ground level with a surface of 0.14 m2 each. The unheated precipitation collector consists of a 30 cm-long, extended funnel with its orifice at 2.3 m above ground. Daily snowmelt samples were collected with both systems during two snowfall-snowmelt periods in 2016. The snowmelt lysimeter system provided more accurate measurements of natural melt rates and allowed for capturing the small-scale variability of snowmelt process at the plot scale, such as lateral meltwater flow from the surrounding snowpack. Because of the restricted volume of the extended funnel, daily melt rates from the unheated precipitation collector were up to 43% smaller compared to the snowmelt lysimeter system. Overall, both snowmelt collection methods captured the general temporal evolution of the isotopic signature in snowmelt.

scholarly journals Isotopic hydrograph separation in two small mountain catchments during multiple events

2018 ◽  
Vol 44 (2) ◽  
pp. 453 ◽  
Author(s):  
L. Holko ◽  
S. Bičárová ◽  
J. Hlavčo ◽  
M. Danko ◽  
Z. Kostka
Keyword(s):  
Isotopic Composition ◽  
Elevation Gradient ◽  
Rain Gauge ◽  
Windward Side ◽  
Storm Event ◽  
Hydrograph Separation ◽  
Tatra Mountains ◽  
Isotopic Signatures ◽  
Water Fractions ◽  
End Members

Two-component isotopic hydrograph separation (IHS) was developed to determine the event- and pre-event components of a single storm event. Its application for several sucessive events requires repeated determination of isotopic signatures of end-members (precipitation, pre-event component) for each event. The existence of several possible alternative signatures results in differences in calculated contributions of event-/pre- event components. This article addresses the question of how big the differences could be in small mountain catchments with different methods for detemining the end member signatures. We analyzed data on isotopic composition of daily/event precipitation at different elevations in two catchments located in the highest part of the Carpathians in July 2014.The isotopic composition of streamflow sampled every 4-6 hours was analyzed as well. Elevational gradients of δ18O and δ2H in precipitation in the study period were -0.18 ‰ 100 m-1 and -1.1 ‰ 100 m-1, respectively. An elevation gradient in deuterium excess (0.29 ‰ 100 m-1) was also found. Precipitation on the windward side of the mountains was isotopically lighter than expected for a given rain gauge elevation. Five large rainfall-runoff events occurred in the study period in the meso-scale catchment of the Jalovecký creek (Western Tatra Mountains, area 22.2 km2) and in the headwater catchment of the Škaredý creek (High Tatra Mountains, area 1.4 km2). Isotopic hydrograph separation was conducted using eight options for the isotopic signatures of event and pre-event water. The isotopic signature of the event water (rainfall) was alternatively represented by data from high or low elevations. Pre-event water was represented either by the streamflow before the event or by the value taken from the statistics of the long-term data on isotopic composition of the stream. Both isotopes (18O and 2H) were used to calculate event water fractions during peak flows of individual events. Calculated peak flow event water fractions were below 0.2-0.3 for most events. However, the differences in calculated event water fractions for alternative isotopic composition of end-members were significant even if we did not take into account changes in isotopic composition during individual rainfalls. Coefficients of variation for event water fractions calculated for various options varied during individual events from 0.14 to 0.36. It is therefore perhaps better to use a range of possible values instead of a single accurate number to interpret the IHS results. Hydrograph separations based on 18O and 2H provided similar results.

scholarly journals Groundwater contribution to river flows – using hydrograph separation, hydrological and hydrogeological models in a southern Quebec aquifer

2010 ◽  
Vol 7 (5) ◽  
pp. 7809-7838 ◽  
Author(s):  
M. Larocque ◽  
V. Fortin ◽  
M. C. Pharand ◽  
C. Rivard
Keyword(s):  
Groundwater Flow ◽  
Flow Model ◽  
Regional Scale ◽  
Significant Proportion ◽  
Base Flow ◽  
Groundwater Flow Model ◽  
Hydrograph Separation ◽  
River Flows ◽  
Groundwater Contribution ◽  
Base Flows

Abstract. Groundwater contribution to river flows, generally called base flows, often accounts for a significant proportion of total flow rate, especially during the dry season. The objective of this work is to test simple approaches requiring limited data to understand groundwater contribution to river flows. The Noire river basin in southern Quebec is used as a case study. A lumped conceptual hydrological model (the MOHYSE model), a groundwater flow model (MODFLOW) and hydrograph separation are used to provide estimates of base flow for the study area. Results show that the methods are complementary. Hydrograph separation and the MOHYSE surface flow model provide similar annual estimates for the groundwater contribution to river flow, but monthly base flows can vary significantly between the two methods. Both methods have the advantage of being easily implemented. However, the distinction between aquifer contribution and shallow subsurface contribution to base flow can only be made with a groundwater flow model. The aquifer renewal rate estimated with the MODFLOW model for the Noire River is 30% of the recharge estimated from base flow values. This is a significantly difference which can be crucial for regional-scale water management.

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