Untangling transient groundwater mixing and travel times with noble gas time series and numerical modeling

2020 ◽  
Author(s):  
Andrea L. Popp ◽  
Álvaro Pardo-Álvarez ◽  
Oliver S. Schilling ◽  
Stéphanie Musy ◽  
Andreas Scheidegger ◽  
...  
Keyword(s):  
Surface Water ◽  
Environmental Changes ◽  
Noble Gas ◽  
Gas Analysis ◽  
Marginal Effect ◽  
Travel Times ◽  
Groundwater Pumping ◽  
Mountainous Regions ◽  
Mixing Ratios ◽  
Groundwater Mixing

<p class="western"><span lang="en-US">The quality and quantity of alluvial groundwater in mountainous areas are particularly susceptible to the effects of climate change, as well as increasing pollution from agriculture and urbanization. Understanding mixing between surface water and groundwater as well as groundwater travel times in such systems is thus crucial to sustain a safe and sufficient water supply. We used a novel combination of real-time, in-situ noble gas analysis to quantify groundwater mixing of recently infiltrated river water (<em>F<sub>rw</sub></em><!-- Please note that everything in “$$” will look differently once submitted -->) and regional groundwater, as well as travel times of <em>F<sub>rw</sub></em> during a two-month groundwater pumping test carried out at a drinking water wellfield in a prealpine valley in Switzerland. Transient groundwater mixing ratios were calculated using helium-4 concentrations combined with a Bayesian end-member mixing model. Having identified the groundwater fraction of <em>F<sub>rw</sub></em> consequently allowed us to infer the travel times from the stream to the wellfield, estimated based on radon-222 activities of <em>F<sub>rw</sub></em>. Additionally, we compared and validated our tracer-based estimates of <em>F<sub>rw</sub></em> using a calibrated surface water-groundwater model. Our findings show that (i) mean travel times of <em>F<sub>rw</sub></em> are in the order of two weeks, (ii) during most of the experiment, <em>F<sub>rw</sub></em> is substantially high (~70\%), and (iii) increased groundwater pumping only has a marginal effect on groundwater mixing ratios and travel times. The high fraction of <em>F<sub>rw</sub></em> in the abstracted groundwater and its short travel times emphasize the vulnerability of mountainous regions to present and predicted environmental changes.</span></p>

Climate and environmental context of the Mongol invasion of Syria and defeat at ‘Ayn Jālūt (1258–1260 CE)

Erdkunde ◽  
2021 ◽  
Vol 75 (2) ◽  
pp. 87-104
Author(s):  
Nicola Di Cosmo ◽  
Sebastian Wagner ◽  
Ulf Büntgen
Keyword(s):  
Strategic Alliances ◽  
Turning Point ◽  
Environmental Changes ◽  
Environmental Variability ◽  
State Of The Art ◽  
Eastern Mediterranean ◽  
The Caucasus ◽  
Mountainous Regions ◽  
The Past ◽  
Climate Reconstructions

After a successful conquest of large parts of Syria in 1258 and 1259 CE, the Mongol army lost the battle of 'Ayn Jālūt against Mamluks on September 3, 1260 CE. Recognized as a turning point in world history, their sudden defeat triggered the reconfiguration of strategic alliances and geopolitical power not only in the Middle East, but also across much of Eurasia. Despite decades of research, scholars have not yet reached consensus over the causes of the Mongol reverse. Here, we revisit previous arguments in light of climate and environmental changes in the aftermath of one the largest volcanic forcings in the past 2500 years, the Samalas eruption ~1257 CE. Regional tree ring-based climate reconstructions and state-of-the-art Earth System Model simulations reveal cooler and wetter conditions from spring 1258 to autumn 1259 CE for the eastern Mediterranean/Arabian region. We therefore hypothesize that the post-Samalas climate anomaly and associated environmental variability affected an estimated 120,000 Mongol soldiers and up to half a million of their horses during the conquest. More specifically, we argue that colder and wetter climates in 1258 and 1259 CE, while complicating and slowing the campaign in certain areas, such as the mountainous regions in the Caucasus and Anatolia, also facilitated the assault on Syria between January and March 1260. A return to warmer and dryer conditions in the summer of 1260 CE, however, likely reduced the regional carrying capacity and may therefore have forced a mass withdrawal of the Mongols from the region that contributed to the Mamluks’ victory. In pointing to a distinct environmental dependency of the Mongols, we offer a new explanation of their defeat at 'Ayn Jālūt, which effectively halted the further expansion of the largest ever land-based empire.

Estimating groundwater mixing ratios and their uncertainties using a statistical multi parameter approach

2005 ◽  
Vol 305 (1-4) ◽  
pp. 1-14 ◽  
Author(s):  
Joerg Rueedi ◽  
Roland Purtschert ◽  
Urs Beyerle ◽  
Carmen Alberich ◽  
Rolf Kipfer
Keyword(s):  
Mixing Ratios ◽  
Groundwater Mixing ◽  
Parameter Approach

scholarly journals Single grain noble gas analysis of Antarctic micrometeorites by stepwise heating method with a newly constructed miniature furnace

2011 ◽  
Vol 63 (10) ◽  
pp. 1097-1111 ◽  
Author(s):  
Ken-ichi Bajo ◽  
Tomohiro Akaida ◽  
Noriaki Ohashi ◽  
Takaaki Noguchi ◽  
Tomoki Nakamura ◽  
...  
Keyword(s):  
Noble Gas ◽  
Gas Analysis ◽  
Heating Method ◽  
Stepwise Heating ◽  
Stepwise Heating Method ◽  
Single Grain

Further evidence for an impact origin of the Tsenkher structure in the Gobi-Altai, Mongolia: geology of a 3.7 km crater with a well-preserved ejecta blanket

2017 ◽  
Vol 156 (1) ◽  
pp. 1-24
Author(s):  
GORO KOMATSU ◽  
JENS ORMÖ ◽  
TOGOOKHUU BAYARAA ◽  
TOMOKO ARAI ◽  
KEISUKE NAGAO ◽  
...  
Keyword(s):  
Noble Gas ◽  
Gas Analysis ◽  
Volcanic Origin ◽  
Large Size ◽  
Deformation Features ◽  
Order Of Magnitude ◽  
Ejecta Blanket ◽  
Planar Deformation Features ◽  
Impact Origin ◽  
Related Sample

AbstractThe Tsenkher structure in the Gobi-Altai, Mongolia is a c. 3.7 km diameter crater with a well-preserved ejecta blanket. It has been hypothesized to be either of impact or volcanic origin in our previous work. Observations during our 2007 expedition and related sample analyses give further support for an impact origin. The evidence includes the presence of a structurally uplifted near-circular rim surrounded by an ejecta blanket, and abundant breccias, some of which are melt- and millimetre-scale spherule-bearing. Planar deformation features (PDFs) were found in one quartz grain in a breccia sample. Fe-rich grains are found in a vesicular melt sample that is also characterized by elevated platinum group element (PGE) abundances with respect to the sedimentary bedrock of the area (approximately an order of magnitude). Noble gas analysis of one breccia sample yielded an elevated 3He/4He value of (5.0±0.2) × 10−6. Although not conclusive alone, these geochemical results are consistent with a contribution of meteoritic components. A volcanic origin, in particular a maar formation, would require explanations for the unusual conditions associated with Tsenkher, including its large size occurring in isolation, the structurally uplifted rim and the lack of a bedded base surge deposit. A pronounced rampart structure observed at the eastern ejecta is also unusual for any volcanic origin. 40Ar–39Ar dating of a vesicular melt sample gives an age of the Tsenkher structure of 4.9±0.9 Ma. The rampart structure could provide insights into the formation of similar ejecta morphologies associated with numerous impact craters on Mars.

Groundwater–surface water interaction in inland New South Wales: a scoping study

2003 ◽  
Vol 48 (7) ◽  
pp. 215-224 ◽  
Author(s):  
R. Braaten ◽  
G. Gates
Keyword(s):  
Surface Water ◽  
New South ◽  
New South Wales ◽  
Groundwater Pumping ◽  
Groundwater Levels ◽  
Depth Data ◽  
Water Interaction ◽  
South Wales ◽  
Groundwater Surface Water Interaction ◽  
Basin Geomorphology

Groundwater and surface water have traditionally been managed separately in New South Wales (NSW). However, where rivers and aquifers are hydraulically connected, groundwater pumping has the potential to deplete streamflow. To highlight the major areas of connection in inland NSW, major streams were overlaid with groundwater depth data and the locations of irrigation bores. A consistent pattern was revealed related to basin geomorphology. The main areas of connection are the mid-sections of the major rivers where alluvial systems are well developed yet still narrow and constricted and groundwater depths are shallow. The mapping was validated and the processes explored by calculating water balances for a connected and disconnected reach in the Murrumbidgee River. These showed that, in highly connected reaches, river losses and/or gains are closely related to groundwater levels.

scholarly journals Evaluation of Radon (222Rn) Distribution and its Implications vis-a-vis Water Quality of Killiyar River, Kerala, India

2021 ◽  
Vol 16 (1) ◽  
pp. 94-104
Author(s):  
Anurani G R ◽  
Lakshmi R ◽  
Joseph Sabu ◽  
Sukanya S
Keyword(s):  
Surface Water ◽  
River Water ◽  
Water Resource Management ◽  
Noble Gas ◽  
Groundwater Potential ◽  
Channel Structure ◽  
Study Region ◽  
Post Monsoon ◽  
Riverine Environment ◽  
Discharge Location

The discharge of tropical rivers is mainly contributed by the baseflow from groundwater especially during summer. Hence, in order to sustain the environmental flow of rivers, the conservation of locations where groundwater discharges into river is a better option than conventional practices viz., redesigning river channel structure and flow regime. Radon (222Rn), a colourless, odourless, inert and natural radioactive noble gas (t1/2= 3.8 days), can be used as a proxy to trace the groundwater discharge location/s in the river course. As 222Rn readily dissolves in groundwater, its content in groundwater is relatively higher than surface water. We report here the activity of 222Rn in the river water at ten locations from upstream to downstream of Killiyar river – KR (n= 6th, L= 24 km, A= 102 km2), the main tributary of Karamana river, Kerala, India. Surface water samples (n=10) were collected during pre- and post-monsoon of 2017. The radon activity was performed by RAD7, an electronic radon detector (Durridge Company Inc., USA). The activity of radon varied from 157 to 4588 Bq/m3 in pre-monsoon and 147 to 1740 Bq/m3 in post-monsoon. The spatial variability of 222Rn activity is observed, and the anomalous high activity location/s indicates groundwater potential in that area. Further, the factors controlling spatial variation of radon were also discussed. Moreover, physico-chemical parameters of river water were also studied. And all the parameters were found to be within the permissible limit of Bureau of Indian Standards (BIS) specifications for potable water (IS -10500: 2012). This is a case study of application of radon for prospecting groundwater potential zones in Killiyar river course, henceforth useful for the water resource management in this riverine environment and is first of its kind in the study region.

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