scholarly journals Characteristics of δ18O and δ2H and their implication for the interaction between precipitation, groundwater and river water in the upper River Tuojiang, Southwest China

2020 ◽  
Author(s):  
Jing Zhou ◽  
Guodong Liu ◽  
Yuchuan Meng ◽  
Cheng Cheng Xia ◽  
Ke Chen
Keyword(s):  
River Water ◽  
Residence Time ◽  
Mean Residence Time ◽  
River Flow ◽  
Water Cycle ◽  
Water Source ◽  
Hydrograph Separation ◽  
Wet Season ◽  
Relative Contribution ◽  
The Mean

Abstract The Tuojiang River has multiple water sources and serious pollution problems, but its hydrological mechanism in the upper reaches is still unclear. To better understand the hydrological characteristics of the Tuojiang River, the isotopic compositions of its precipitation, river water and groundwater in the upper reaches have been investigated from May 2018 to April 2019. The results indicated that the isotope values of precipitation, river water and groundwater fluctuate significantly throughout the year with depleted value in the wet season and enriched value in the dry season. Spatially, the isotope values of river water increase gradually from upstream to downstream. River water is the main source of recharge to groundwater and precipitation is the minor one. The isotope-based hydrograph separation shows that the Mianyuan River and Pihe River contribute more greatly to Tuojiang River than the Shiting River and Yazi River. The mean residence time of river water from the Tuojiang River varies from 0.95 to 1.49 years, which indicates that rivers in the upper reaches of the Tuojiang River respond to precipitation quickly. This study proved the usefulness of stable isotopes to identify the different water cycle components and reflect the pollution problem in multiple water source confluence areas. HIGHLIGHT Analysis of the spatio-temporal characteristics of isotope values in the Tuojiang river basin. Exploration of the seasonal variation of recharge source to groundwater in the Tuojiang River. Analysis of the temporal variation in the relative contribution of tributaries over total river flow. Estimation of the mean residence time of the Tuojiang River and its tributaries.

The mean residence time of river water in the Canada Basin

2008 ◽  
Vol 53 (5) ◽  
pp. 777-783 ◽  
Author(s):  
Min Chen ◽  
Na Xing ◽  
YiPu Huang ◽  
YuSheng Qiu
Keyword(s):  
River Water ◽  
Residence Time ◽  
Mean Residence Time ◽  
Canada Basin ◽  
The Mean

Precipitation and filtration of zinc, magnesium, copper and aluminium hydroxides

1982 ◽  
Vol 47 (12) ◽  
pp. 3362-3370
Author(s):  
Otakar Söhnel ◽  
Eva Matějčková
Keyword(s):  
Residence Time ◽  
Mean Residence Time ◽  
Filtration Resistance ◽  
Filtration Pressure ◽  
Bed Porosity ◽  
The Mean ◽  
Filtration Properties

Filtration properties of batchwise precipitated suspensions of Zn(OH)2, Mg(OH)2 and Cu(OH)2 and continuously precipitated Al(OH)3 were studied. For batchwise precipitated suspensions was verified the theoretically predicted dependence of specific filtration resistance on initial supersaturation and for the continuously precipitated Al(OH)3 the relation between the specific filtration resistance and the mean residence time of suspension in the reactor. Dependences were also recorded between the bed porosity and concentration of precipitated solutions, specific filtration resistance and used filtration pressure and the effect of aging of the batchwise precipitated suspension of Mg(OH)2on its filtration properties. The used CST method for determination of filtration characteristics of Zn(OH)2 suspension was also studied.

Nitrogen use efficiency: does a trade-off exist between the N productivity and the mean residence time within species?

2008 ◽  
Vol 56 (3) ◽  
pp. 272 ◽  
Author(s):  
Zhi Y. Yuan ◽  
Han Y. H. Chen ◽  
Ling H. Li
Keyword(s):  
Residence Time ◽  
Nitrogen Use Efficiency ◽  
Mean Residence Time ◽  
Negative Relationship ◽  
Controlled Experiments ◽  
Nitrogen Use ◽  
Trade Off ◽  
N Supply ◽  
Use Efficiency ◽  
The Mean

Nitrogen use efficiency (NUE) can be divided into two components, i.e. N productivity (A) and the mean residence time (MRT). Controlled experiments indicate that there is not a trade-off between A and MRT within species, but this theory has not been well tested in field conditions. Here, we studied the A, MRT and NUE of Stipa krylovii Roshev. in a grassland over 4 years of N fertilisation experimentation. The three parameters (A, MRT and NUE) were significantly related to soil N supply and there was a negative relationship between A and MRT within this species (r = –0.775, P < 0.05), i.e. plants with higher A had lower MRT. Our results showed a trade-off between A and MRT within this Stipa species and this observed trade-off was attributed to different responses of A and MRT to soil fertility.

scholarly journals Submarine Groundwater Discharge From Sediments and Sand Boils Quantified by the Mean Residence Time of a Tracer Injection

2021 ◽  
Vol 9 ◽  
Author(s):  
Michael Schlüter ◽  
Philipp Maier
Keyword(s):  
Residence Time ◽  
Mean Residence Time ◽  
Submarine Groundwater Discharge ◽  
Groundwater Discharge ◽  
Tracer Injection ◽  
Discharge Rates ◽  
Seepage Meter ◽  
Submarine Groundwater ◽  
Sand Boils ◽  
The Mean

To quantify submarine groundwater discharge, we developed an inexpensive automated seepage meter that applies a tracer injection and the computation of the mean residence time. The SGD-MRT is designed to measure a wide range of discharge rates from about 30 to 800 cm³/min and allows minimizing backpressures caused by pipe friction or flow sensors. By modifying the inner volume of the flow-through unit, the range of measurement is adjustable to lower or higher discharge rates. For process control and data acquisition, an Arduino controller board is used. In addition, components like temperature, conductivity, and pressure sensors or pumps extend the scope of the seepage meter. During field tests in the Wadden Sea, covering tidal cycles, discharge rates of more than 700 cm³/min were released from sand boils. Based on the measured discharge rates and numerical integration of the time series data, a water volume of about 400 dm3 with a seawater content of less than 12% was released from the sand boil within 7 h.

Modeling the Mean Residence Time of Liquid Phase in the Gas–Liquid Cyclone

2015 ◽  
Vol 54 (43) ◽  
pp. 10885-10892 ◽  
Author(s):  
Junwei Yang ◽  
Xupeng Zhang ◽  
Guoping Shen ◽  
Jiazhi Xiao ◽  
Youhai Jin
Keyword(s):  
Liquid Phase ◽  
Residence Time ◽  
Mean Residence Time ◽  
The Mean
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