scholarly journals Features of Oxygen and Hydrogen Isotopes in Waters from the Karst Mountains, Xiangxi River Basin

2020 ◽  
Vol 15 (5) ◽  
pp. 667-675
Author(s):  
Tingting Shi ◽  
Zhihua Chen ◽  
Qing Wang ◽  
Wei Zhang ◽  
Mingming Luo ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
River Basin ◽  
Stream Water ◽  
Water Sources ◽  
Seasonal Effect ◽  
Control Factors ◽  
Xiangxi River ◽  
The Mean ◽  
Δ18o And Δd ◽  
Elevation Effect

Targeting the carbonate-dominated catchment of Xiangxi River, the first tributary of Three Gorges Reservoir, this paper explores the spatiotemporal distribution of stable isotopes in the stream water, and distinguishes the water sources and recharge processes in the river basin. Multiple water samples were collected from the catchments of the main tributaries of Xiangxi River, namely, Nanyang River and Gaolan River. The results show that the two tributary catchments had obvious spatial and seasonable variability in δ18O and δD. This is attributable to the seasonal changes in meteoric precipitation recharge, which depends on ambient temperature, precipitation, evaporation, and secondary evaporation of raindrops. Besides, there is a strong elevation effect on stable isotopes in stream water. In the samples from Gaolan River, the mean elevation effect on the δ18O and δD was -0.35‰, and -1.57‰ per 100m change in elevation in summer, and -0.12‰, and -1.19‰ per 100m change in elevation in winter, respectively. In the samples from Nanyang River, the mean elevation effect on the δ18O and δD was -0.14‰ and -0.89‰ per 100m change in elevation in summer, and -0.08‰ and -0.66‰ per 100m change in elevation in winter, respectively. The δD, δ18O, and deuterium excess (d-value) are not only affected by the elevation effect, but also by the seasonal effect in the study area. The seasonal variations and spatial changes in the tributary catchments reveal the difference between the two catchments in control factors like latitude effect, evaporation, and the mixing of different water sources.

Spatial variation of stream water chemistry in the Shimanto River Basin in southwestern Japan: A comparison of results in 1999 and 2020

2021 ◽  
Author(s):  
Yoshiyuki Inagaki ◽  
Masahiro Inagaki ◽  
Koji Shichi ◽  
Shuichiro Yoshinaga ◽  
Tsuyoshi Yamada ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Water Chemistry ◽  
River Basin ◽  
Forest Ecosystems ◽  
Stream Water ◽  
Mean Annual Temperature ◽  
Sulfate Concentration ◽  
Stream Water Chemistry ◽  
The Mean ◽  
Mean Concentration

<p>Acidic deposition derived from human activities causes negative effects on nutrient cycling in forest ecosystems.  However, nutrient cycling of forest ecosystems is expected to recover because the emission of pollutants is generally decreasing in recent years.  However, the extent of recovery would be differed between forest ecosystems in different climatic conditions.  The study investigated changes of stream water chemistry of forest ecosystems in Shimanto River Basin in southwestern Japan.  The 92 samples of stream water were collected from forested watersheds in summer of 1999 and 2020 and chemistry of the samples was compared.  The mean pH value of the stream water in 2020 (7.60) was higher than that in 1999 (7.29).  The mean concentration of potassium ion increased by 2.1% whereas that of sodium, calcium, and magnesium ions decreased by 2.5%, 10.3%, and 8.6%, respectively.  The mean concentration of chloride, nitrate and sulfate ions decreased by 24.8%, 9.4% and 22.5%, respectively whereas that of bicarbonate increased by 0.7%. 　The relationship between mean annual temperature and the ratio of ion concentration in 2020 to that in 1999 was analyzed.  The ratio of calcium and manganese concentration was lower at warmer sites.  The ratio of sulfate concentration was lower at warmer sites whereas the ratio of chloride concentration was not related with mean annual temperature.  The results suggest that the runoff of sulfate and chloride from forest ecosystems in the Shimanto River Basin have decreased presumably due to the reduced input of these elements and that the residence time of sulfur in forest ecosystems is shorter in warmer sites as indicated by the greater reduction of sulfate concentration.</p><p> </p>

Seasonal trends in the stable isotopic composition of snow and meltwater runoff in a subarctic catchment at Okstindan, Norway

2004 ◽  
Vol 35 (2) ◽  
pp. 119-137 ◽  
Author(s):  
S.D. Gurney ◽  
D.S.L. Lawrence
Keyword(s):  
Isotopic Composition ◽  
Mean Value ◽  
Mean Values ◽  
Stable Isotopic Composition ◽  
Meltwater Runoff ◽  
Stable Isotopic ◽  
The Mean ◽  
The Difference ◽  
Δ18o And Δd

Seasonal variations in the stable isotopic composition of snow and meltwater were investigated in a sub-arctic, mountainous, but non-glacial, catchment at Okstindan in northern Norway based on analyses of δ18O and δD. Samples were collected during four field periods (August 1998; April 1999; June 1999 and August 1999) at three sites lying on an altitudinal transect (740–970 m a.s.l.). Snowpack data display an increase in the mean values of δ18O (increasing from a mean value of −13.51 to −11.49‰ between April and August), as well as a decrease in variability through the melt period. Comparison with a regional meteoric water line indicates that the slope of the δ18O–δD line for the snowpacks decreases over the same period, dropping from 7.49 to approximately 6.2.This change points to the role of evaporation in snowpack ablation and is confirmed by the vertical profile of deuterium excess. Snowpack seepage data, although limited, also suggest reduced values of δD, as might be associated with local evaporation during meltwater generation. In general, meltwaters were depleted in δ18O relative to the source snowpack at the peak of the melt (June), but later in the year (August) the difference between the two was not statistically significant. The diurnal pattern of isotopic composition indicates that the most depleted meltwaters coincide with the peak in temperature and, hence, meltwater production.

Spatial and temporal characteristics of stable isotopes in the Tarim River Basin

2016 ◽  
Vol 52 (3) ◽  
pp. 281-297 ◽  
Author(s):  
Congjian Sun ◽  
Xingong Li ◽  
Yaning Chen ◽  
Weihong Li ◽  
Randy L. Stotler ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
River Basin ◽  
Tarim River ◽  
Tarim River Basin ◽  
Temporal Characteristics ◽  
The Tarim River ◽  
The Tarim River Basin ◽  
Spatial And Temporal Characteristics

scholarly journals Assessments of seasonal groundwater recharge and discharge using environmental stable isotopes at Lower Muda River Basin, Malaysia

2018 ◽  
Vol 8 (5) ◽  
Author(s):  
Mohd Khairul Nizar Shamsuddin ◽  
Wan Nor Azmin Sulaiman ◽  
Mohammad Firuz Ramli ◽  
Faradiella Mohd Kusin ◽  
Kamarudin Samuding
Keyword(s):  
Stable Isotopes ◽  
Groundwater Recharge ◽  
River Basin

scholarly journals Effect on nitrate concentration in stream water of agricultural practices in small catchments in Brittany: I. Annual nitrogen budgets

2002 ◽  
Vol 6 (3) ◽  
pp. 497-506 ◽  
Author(s):  
L. Ruiz ◽  
S. Abiven ◽  
P. Durand ◽  
C. Martin ◽  
F. Vertès ◽  
...  
Keyword(s):  
Land Use ◽  
Nitrate Concentration ◽  
Stream Water ◽  
Agricultural Practices ◽  
Climatic Conditions ◽  
Nitrogen Budgets ◽  
Annual Variations ◽  
Nitrate Concentrations ◽  
The Mean ◽  
Small Catchments

Abstract. The hydrological and biogeochemical monitoring of catchments has become a common approach for studying the effect of the evolution of agricultural practices on water resources. In numerous studies, the catchment is used as a "mega-lysimeter" to calculate annual input-output budgets. However, the literature reflects two opposite interpretations of the trends of nitrate concentration in streamwater. For some authors, essentially in applied studies, the mean residence time of leached nitrate in shallow groundwater systems is much less than one year and river loads reflect annual land use while for others, nitrate is essentially transport limited, independent of soil nitrate supply in the short term and annual variations reflect changes in climatic conditions. This study tests the effect of agricultural land-use changes on inter-annual nitrate trends on stream water of six small adjacent catchments from 0.10 to 0.57 km2 in area, on granite bedrock, at Kerbernez, in Western Brittany (France). Nitrate concentrations and loads in streamwater have been monitored for nine years (1992 to 2000) at the outlet of the catchments. An extensive survey of agricultural practices from 1993 to 1999 allowed assessment of the nitrogen available for leaching through nitrogen budgets. For such small catchments, year-to-year variations of nitrate leaching can be very important, even when considering the 'memory effect' of soil, while nitrate concentrations in streamwater appear relatively steady. No correlation was found between the calculated mean nitrate concentration of drainage water and the mean annual concentration in streams, which can even exhibit opposite trends in inter-annual variations. The climatic conditions do not affect the mean concentration in streamwater significantly. These results suggest that groundwater plays an important role in the control of streamwater nitrate concentration. Keywords: nitrate, diffuse pollution, agricultural catchment, nitrogen budget, leaching, Kerbernez catchments

scholarly journals Classification of Stable Isotopes and Identification of Water Replenishment in the Naqu River Basin, Qinghai-Tibet Plateau

Water ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 46 ◽  
Author(s):  
Xi Chen ◽  
Guoli Wang ◽  
Fuqiang Wang
Keyword(s):  
Stable Isotopes ◽  
River Basin ◽  
Source Identification ◽  
Evaluation Model ◽  
Tibet Plateau ◽  
High Status ◽  
Fuzzy Evaluation ◽  
Isotopic Study ◽  
Qinghai Tibet Plateau

The stable isotopic study of the mechanism of runoff replenishment in the Qinghai-Tibet Plateau is a time-consuming and complicated process requiring complex monitoring data and scientific evaluation methods. Based on the data of water stable isotopes (18O and 2H) in the Naqu River basin, the present paper developed a framework of the variable fuzzy evaluation model (VFEM) to provide a method to classify stable isotopes and generalize the source identification of water replenishment by rainfall or snowmelt in the Naqu River basin. The grade eigenvalues of tributaries were ranked from low to high as follows: 1, 1.005, 1.089, 1.151, 1.264, 1.455 and 2.624. Three sets of tributaries were distinguished. The grade eigenvalues of the Najinqu, Bazongqu, Mumuqu, Chengqu and Gongqu Rivers were small, indicating that these tributaries were strongly supplemented by precipitation and snowmelt; the grade eigenvalue of the Zongqingqu River was in the medium range (1.455); the third group included the Mugequ River with a high status value (2.624). This study mainly highlighted the combination of the classification of stable isotopes and plots of δ2H vs. δ18O in the source identification of water replenishment, which will be helpful for studying runoff replenishment and the evolution mechanism in the Qinghai-Tibet Plateau.

Stable Isotopes Analysis of Precipitation in Subtropical Plateau of Yunnan

2014 ◽  
Vol 1010-1012 ◽  
pp. 1059-1063
Author(s):  
Wei Guan ◽  
Tao Fan ◽  
Xiu Qin Zhu
Keyword(s):  
Stable Isotopes ◽  
Rainy Season ◽  
Mean Value ◽  
Dry Season ◽  
Precipitation Line ◽  
Stable Isotopic ◽  
Different Seasons ◽  
Geographical Position ◽  
The Mean ◽  
The Relationship

To elucidate the relationship between stable isotopes of precipitation (SIP) and the extreme drought in Kunming area, based on the stable isotopes data of the GNIP in Kunming site from 1986 to 2003, the precipitation line equation is brought forward and the seasonal change rule of stable isotopes are discussed. The stable isotopic compositions of precipitation exhibit great diversities in different seasons during to influences of multiple factors, such as monsoon, rainfall amount moisture source and others. The δ18O values in rainwater exhibit significant seasonal variations, the average of-10.12‰ in rainy season, the dry season is-4.5‰, having lower values in the rainy season and higher one in the dry season. The amount effect of precipitation is very distinct, that concealed the temperature effect. Got the special geographical position,dvalues present unique characteristics, the average ofdvalues is 10.78‰ in rainy season, and is 4.86‰ in dry season, the mean value is generally lower than most parts of the world.

scholarly journals Features of the Spring Flood Formation in the Arpa River Basin

2021 ◽  
pp. 126-152
Author(s):  
Keyword(s):  
River Basin ◽  
Weighted Average ◽  
Close Correlation ◽  
Annual Runoff ◽  
Average Height ◽  
Spring Flood ◽  
Correlation Relationship ◽  
Catchment Areas ◽  
The Mean ◽  
Maximum Runoff

The article considers main physical and geographical factors affecting the runoff, spring flood of rivers in the Arpa River basin, and analyzes the regularities of their spacetime distribution. The authors have obtained correlation relationship between the values of the flood runoff layer, the mean module maximum runoff and weighted average height of the catchment area of the Arpa River, between the mean annual maximum runoff module for the period floods and catchment areas of rivers. These dependencies can be used for preliminary estimates of the spring flood runoff of unexplored rivers of the territory under consideration. A close correlation between the values of the annual runoff and the runoff of the spring flood in the section of the Arpa River – Dzhermuk has been also revealed. It can be used for forecasting the annual flow.

Sign in / Sign up

Export Citation Format

Share Document