scholarly journals Stalagmite water content as a proxy for drip water supply in tropical and subtropical areas

2013 ◽  
Vol 9 (1) ◽  
pp. 1-12 ◽  
Author(s):  
N. Vogel ◽  
Y. Scheidegger ◽  
M. S. Brennwald ◽  
D. Fleitmann ◽  
S. Figura ◽  
...  
Keyword(s):  
Water Supply ◽  
Water Content ◽  
Water Yield ◽  
Thin Sections ◽  
Drip Water ◽  
Optical Inspection ◽  
Socotra Island ◽  
Oxygen Isotopic ◽  
Yield Record ◽  
Irregular Growth

Abstract. In this pilot study water was extracted from samples of two Holocene stalagmites from Socotra Island, Yemen, and one Eemian stalagmite from southern continental Yemen. The amount of water extracted per unit mass of stalagmite rock, termed "water yield" hereafter, serves as a measure of its total water content. Based on direct correlation plots of water yields and δ18Ocalcite and on regime shift analyses, we demonstrate that for the studied stalagmites the water yield records vary systematically with the corresponding oxygen isotopic compositions of the calcite (δ18Ocalcite). Within each stalagmite lower δ18Ocalcite values are accompanied by lower water yields and vice versa. The δ18Ocalcite records of the studied stalagmites have previously been interpreted to predominantly reflect the amount of rainfall in the area; thus, water yields can be linked to drip water supply. Higher, and therefore more continuous drip water supply caused by higher rainfall rates, supports homogeneous deposition of calcite with low porosity and therefore a small fraction of water-filled inclusions, resulting in low water yields of the respective samples. A reduction of drip water supply fosters irregular growth of calcite with higher porosity, leading to an increase of the fraction of water-filled inclusions and thus higher water yields. The results are consistent with the literature on stalagmite growth and supported by optical inspection of thin sections of our samples. We propose that for a stalagmite from a dry tropical or subtropical area, its water yield record represents a novel paleo-climate proxy recording changes in drip water supply, which can in turn be interpreted in terms of associated rainfall rates.

scholarly journals Stalagmite water content as a proxy for drip water supply in tropical and subtropical areas

2012 ◽  
Vol 8 (4) ◽  
pp. 2893-2920
Author(s):  
N. Vogel ◽  
Y. Scheidegger ◽  
M. S. Brennwald ◽  
D. Fleitmann ◽  
S. Figura ◽  
...  
Keyword(s):  
Water Supply ◽  
Water Content ◽  
Water Yield ◽  
Thin Sections ◽  
Drip Water ◽  
Socotra Island ◽  
Oxygen Isotopic ◽  
High Precipitation ◽  
Yield Record ◽  
Paleoclimate Proxy

Abstract. In this pilot study water was extracted from samples of two Holocene stalagmites from Socotra Island, Yemen, and one Eemian stalagmite from southern continental Yemen. The amount of water extracted per unit mass of stalagmite rock, termed "water yield" hereafter, serves as a measure for its total water content. The stalagmites' water yield records vary systematically with the corresponding oxygen isotopic compositions of the calcite (δ18Ocalcite). Low δ18Ocalcite values are thereby accompanied by low water yields and vice versa. Based on the paleoclimatic interpretation of the δ18Ocalcite records, water yields can be linked to drip water supply. High drip water supply caused by high precipitation rates supports homogeneous deposition of calcite with low porosity and therefore a small fraction of water-filled inclusions, resulting in low water yields of the respective samples. A reduction of drip water supply fosters irregular growth of calcite with higher porosity, leading to an increase of the fraction of water-filled inclusions and thus higher water yields. The results are consistent with the literature on stalagmite growth and supported by optical inspection of thin sections of our samples. We propose that for a stalagmite from a tropical or subtropical area, its water yield record represents a novel paleoclimate proxy recording changes in drip water supply, which can in turn be interpreted in terms of associated precipitation rates.

scholarly journals Spatio-temporal variation of water supply in Guizhou Province, China

Water Policy ◽  
2016 ◽  
Vol 19 (1) ◽  
pp. 181-195 ◽  
Author(s):  
Huiqing Han ◽  
Yuxiang Dong
Keyword(s):  
Land Use ◽  
Water Supply ◽  
Urban Expansion ◽  
Guizhou Province ◽  
Water Yield ◽  
Freshwater Ecosystem ◽  
Yield Model ◽  
Invest Model ◽  
Spatio Temporal ◽  
The Impact

Water supply is an important freshwater ecosystem service provided by ecosystems. Water shortages resulting from spatio-temporal heterogeneity of climate condition or human activities present serious problems in the Guizhou Province of southwest China. This study aimed to analyze the spatio-temporal changes of water supply service using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, explore how climate and land-use changes impact water supply provision, and discuss the impact of parameters associated with climate and land-use in the InVEST model on water supply in the region. We used data and the model to forecast trends for the year 2030 and found that water supply has been declining in the region at the watershed scale since 1990. Climate and land-use change played important roles in affecting the water supply. Water supply was overwhelmingly driven by the reference evapotranspiration and annual average precipitation, while the plant evapotranspiration coefficients for each land-use type had a relatively small effect. The method for sensitivity analysis developed in this study allowed exploration of the relative importance of parameters in the InVEST water yield model. The Grain-for-Green project, afforestation, and urban expansion control should be accelerated in this region to protect the water supply.

scholarly journals A Qualitative Study of the Critical Conditions for the Initiation of Mine Waste Debris Flows

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1536
Author(s):  
Yanbo Cao ◽  
Xinghua Zhu ◽  
Bangxiao Liu ◽  
Yalin Nan
Keyword(s):  
Debris Flow ◽  
Water Supply ◽  
Water Content ◽  
Debris Flows ◽  
Discharge Rate ◽  
Mine Waste ◽  
Clay Particle ◽  
Critical Conditions ◽  
Particle Content ◽  
Parabolic Relationship

Mine waste debris flows are a type of man-made debris flow that commonly lead to major disasters. In this study, the Xiaotong Gully, which is located in the Xiaoqinling gold mining area in China and contains a typical mine waste debris flow gully, was selected as the study area. Since a debris flow can be classified as either a geotechnical debris flow or hydraulic debris flow based on its initiation mode, we conducted 46 experimental model tests to explore the initiation conditions of these two different types of debris flows. According to our tests, the initiation conditions of hydraulic debris flows were mainly affected by the flume gradient, the water content of the mine waste, the inflow discharge, the water supply modes, and the clay particle content. A larger flume gradient and higher mine waste water content were more conducive to initiating a hydraulic debris flow. However, the influence of the water supply mode on the initiation of a hydraulic debris flow was complex (influenced by factors such as water content of mine waste, runoff discharge rate and rainfall intensity). The critical runoff of a hydraulic debris flow, which starts with a parabolic relationship to the clay particle content of the mine waste, decreased with increasing clay particle content and then increased. There was a minimum critical runoff when the clay content of the mine waste was 30%. The initiation conditions of a geotechnical debris flow were mainly affected by the flume gradient, the water content, and the clay particle content. The critical gradient of a geotechnical debris flow decreased with increasing water content and had a parabolic relationship to the clay particle content. In tests 31–46 of this study, the second and third critical slopes both decreased and then increased with increasing clay particle content. These preliminary research results provide a scientific reference for subsequent research on the prevention and mitigation of mine waste debris flows.

Water-Activated Bacterial Cellulose-Based Electrorheological Fluids and Electromechanical Response of Artificial Muscle Based on Electrorheological Fluids and Siloxane Gel

2009 ◽  
Vol 87-88 ◽  
pp. 143-148
Author(s):  
Nai Xu ◽  
De Min Jia
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Water Content ◽  
Bacterial Cellulose ◽  
Yield Stress ◽  
Particle Concentration ◽  
Electrorheological Fluids ◽  
Water Yield ◽  
Composite Gel

Electrorheological (ER) characteristics of ER fluids (ERF) containing bacterial cellulose (BC) particles in silicone oil was investigated as a function of particle water content, DC electric field strength and particle concentration. It was found that the existence of water in BC particles strongly influenced the performance of water-activated ERF based on BC particles. Around 8.8 wt% water, yield stress reached its maximum valve of 1118 Pa after which it decreased with increasing water content. At the same water content, yield stress increased linearly with increasing in either electric field strength or particle concentration. The ERF based on BC particles was introduced into the poly (dimethylsiloxane) (PDMS) gels to prepare electric field sensitive composite gel. Electric fields were applied to these composite gels using flexible electrodes. Compressions of these gels with varying PDMS/ERF ratios were confirmed by the electrode displacement. It was found that 50/50 PDMS/ERF gel exhibited the maximum displacement of 102um at 2 kV/mm electric field.

Oxygen isotopic fractionation between drip water and speleothem calcite: A 10-year monitoring study, central Texas, USA

2012 ◽  
Vol 304-305 ◽  
pp. 53-67 ◽  
Author(s):  
Weimin Feng ◽  
Jay L. Banner ◽  
Amber L. Guilfoyle ◽  
MaryLynn Musgrove ◽  
Eric W. James
Keyword(s):  
Isotopic Fractionation ◽  
Drip Water ◽  
Monitoring Study ◽  
Central Texas ◽  
Oxygen Isotopic

scholarly journals Analysis of water yield service of Lianshui River Basin in China based on ecosystem services flow model

2021 ◽  
Author(s):  
Yang Zou ◽  
DeHua Mao
Keyword(s):  
Water Resources ◽  
Water Supply ◽  
Urban Area ◽  
River Basin ◽  
Flow Model ◽  
Water Security ◽  
Water Saving ◽  
Water Yield ◽  
Security Assessment ◽  
Service Flow

Abstract Water security assessment is very important to social development. However, most studies only focus on the status quo of water security in a static state and ignore the flow characteristics of water resources into the water security assessment. This paper integrates multi-source data to construct a water supply and service supply-demand balance and spatial flow model in the Lianshui River Basin, simulates the spatial pattern of the service flow of the aquatic water ecosystem in the Lianshui River Basin from 1990 to 2018, and quantifies the service flow. Results show that (1) From 1990 to 2018, the water supply in the Lianshui River Basin first decreased, then increased, and finally decreased. Water yield was the highest in 2010 and lowest in 2000. (2) Water demand increased year by year, and the amount of area with a poor water resource security index increased, indicating that water security was deteriorating. (3) The four main beneficiary areas in the basin are the urban area of Lianyuan City, the county seat of Shuangfeng County, the Louxing District of Loudi City, and the urban area of Xiangxiang City and nearby towns. The service flow showed the same changing trend as the water yield. In 2018, the water resource gap in the beneficiary area was as high as 4.49 billion m3. Local governments should actively build a water-saving society, improve the efficiency of industrial and agricultural water-saving and residents' awareness of water-saving, and improve the water resources in the river basin. The research can provide a scientific basis for realizing the sustainable development of water resources in the Lianshui River Basin and improving the ecological compensation mechanism, and can also provide references for water resources management in other river basins.

scholarly journals 696 PB 280 REDUCED WATER SUPPLY AFFECTS FALL ACCLIMATION OF EVERGREEN AZALEAS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 532e-532
Author(s):  
Tomasz Anisko ◽  
Orville M. Lindstrom
Keyword(s):  
Water Supply ◽  
Water Content ◽  
Freeze Tolerance ◽  
The Other ◽  
Plant Parts ◽  
Growing Medium ◽  
Lower Water Content ◽  
Reduced Water

Three cultivars of evergreen azaleas, `Coral Bell', `Hinodegiri', and `Red Ruffle', were grown under four watering regimes in containers and placed outdoors or in the greenhouse. The water content of the growing medium was maintained at either 0.3 to 0.4 or 0.5 to 0.6 m3m-3 from June 16 to August 30, when half of the plants under each of these regime was switched to the other watering regime. Freeze tests were conducted on August 30 and October 9, 1993. Injury to leaves, lower, middle, and upper stems was evaluated visually. Acclimation of leaves and upper stems prior to the August test, in most cases, was not stimulated by reduced water content, while the response of lower and middle stems was cultivar and location specific. The lower water content treatment after August 30 generally increased freeze tolerance of all plant parts regardless of the previous watering regime. The higher water content treatment after August 30 either prevented or delayed acclimation.

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