GRAND CANYON GROUNDWATER RECHARGE SOURCES AND FLOW PATHS: A MULTI-TRACER ASSESSMENT OF A CONCEPTUAL FLOW MODEL

2020 ◽  
Author(s):  
John Solder ◽  
◽  
Kimberly R. Beisner ◽  
Jessica Anderson ◽  
Donald J. Bills
2021 ◽  
Author(s):  
Uwe Morgenstern ◽  
Zara Rawlinson

<p>Geologic data to provide information on the functioning of aquifers is often scars. For the aquifers underlying the Heretaunga Plains, Hawkes Bay, one of New Zealand’s most important groundwater systems, we used groundwater age (tritium, SF6, 14C) to inform the geologic model and to provide information on groundwater flow through alternating strata of permeable river gravel beds and fine impermeable beds that form an interconnected unconfined–confined aquifer system with complex groundwater flow processes.</p><p>The aquifers are a result of geological processes responding to climate change cycles from cold glacial when sea level was more than 100m below present sea level, to warm interglacial periods with sea level similar to present day. Glacial climate strata are river gravel, sand and silt deposits and include the artesian aquifers. The interglacial strata form the aquicludes and are marine sand, silt, and clay deposits with interbedded estuarine, swamp and coastal fluvial silt, clay, peat and gravel deposits.</p><p>We have re-visited tracer data sampled during the drilling of multi-level observation well in the early 1990s, and collected new samples from these multi-level bores in order to understand in 3D the groundwater recharge sources, groundwater recharge and flow rates, connection to the rivers, and potential groundwater discharge out to sea. Consistently young water (c. 25 years) at depth greater than 100m indicates preferential flow paths, likely related to paleo-river channels. The flow pattern obtained from the water tracer data improves the geologic information from the drill-holes, and fits with information from recent airborne transient electromagnetic (SkyTEM) geophysical surveys.</p>


2008 ◽  
Vol 12 (1) ◽  
pp. 1-19 ◽  
Author(s):  
M. K. Stewart ◽  
J. T. Thomas

Abstract. The Waikoropupu Springs, a large karst resurgence 4 km from the coast, are supplied by the Arthur Marble Aquifer (AMA) underlying the Takaka Valley, South Island, New Zealand. New evidence on the recharge sources in the catchment, combined with previous results, is used to establish a new recharge model for the AMA. Combined with the oxygen-18 mass balance, this yields a quantitative description of the inputs and outputs to the aquifer. It shows that the Main Spring is sourced mainly from the karst uplands (74%), with smaller contributions from the Upper Takaka River (18%) and valley rainfall (8%), while Fish Creek Spring contains mostly Upper Takaka River water (50%). In addition, much of the Upper Takaka River contribution to the aquifer (58%) bypasses the springs and is discharged offshore via submarine springs. The chemical concentrations of the Main Spring show input of 0.5% of sea water on average, which varies with flow and derives from the deep aquifer. Tritium measurements spanning 40 yr, and CFC-11 measurements, give a mean residence time of 8 yr for the Main Spring water using the preferred two-component model. Our conceptual flow model, based on the flow, chloride, oxygen-18 and age measurements, invokes two different flow systems with different recharge sources to explain the flow within the AMA. One system contains deeply penetrating old water with mean age 10.2 yr and water volume 3 km3, recharged from the karst uplands. The other, at shallow levels below the valley floor, has much younger water with mean age 1.2 yr and water volume 0.4 km3, recharged by Upper Takaka River and valley rainfall. The flow systems contribute in different proportions to the Main Spring, Fish Creek Springs and offshore springs. Their very different behaviours, despite being in the same aquifer, are attributed to the presence of a diorite intrusion below the surface of the lower valley, which diverts the deep flow towards the Waikoropupu Springs and allows much of the shallow flow to pass over the intrusive and escape via submarine springs.


Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 278 ◽  
Author(s):  
Takeo Tsuchihara ◽  
Katsushi Shirahata ◽  
Satoshi Ishida ◽  
Shuhei Yoshimoto

Paddy rice fields on an alluvial fan not only use groundwater for irrigation but also play an important role as groundwater recharge sources. In this study, we investigated the spatial distribution of isotopic and hydrochemical compositions of groundwater in the Nasunogahara alluvial fan in Japan and applied a self-organizing map (SOM) to characterize the groundwater. The SOM assisted with the hydrochemical and isotopic interpretation of the groundwater in the fan, and clearly classified the groundwater into four groups reflecting the different origins. Two groundwater groups with lower isotopic ratios of water than the mean precipitation values in the fan were influenced by the infiltration of river water flowing from higher areas in the catchments and were differentiated from each other by their Na+ and Cl− concentrations. A groundwater group with higher isotopic ratios was influenced by the infiltration of paddy irrigation water that had experienced evaporative isotopic enrichment. Groundwater in the fourth group, which was distributed in the upstream area of the fan where dairy farms dominated, showed little influence of recharge waters from paddy rice fields. The findings of this study will contribute to proper management of the groundwater resources in the fan.


Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 561 ◽  
Author(s):  
Ze-Yuan Yang ◽  
Kai Wang ◽  
Yue Yuan ◽  
Jinting Huang ◽  
Zhi-Jun Chen ◽  
...  

Groundwater is often the main source of available water, and precipitation is one of the main recharge sources of groundwater in arid and semi-arid regions. This paper studies a fixed dune in Mu Us Sandy Land in China, establishes a numerical model, acquires hydraulic parameters and heat parameters of the vadose zone, and calculates the recharge coefficient based on field observation data and numerical modelling. These measurement results show that the response depths of storm rain are more than 90 cm, while those of small rain events are less than 10 cm. The numerical results show that infiltration depths are 10 cm for small rain and more than 90 cm for middle rain respectively. The lag time of the water content at 90 cm below the surface was 25 h following a middle rain, 18–19 h following a heavy rain, and 16–18 h following a storm rainfall. Groundwater recharge lag times (matrix flow) varied from 11 h to 48 h. Excluded precipitation for groundwater recharge was 11.25–11.75 mm in 1 h when groundwater depth was 120 cm and 15–15.5 mm when 140 cm, showing significant influence in groundwater resource evaluation.


2016 ◽  
Vol 24 (8) ◽  
pp. 1967-1979 ◽  
Author(s):  
Liheng Wang ◽  
Yanhui Dong ◽  
Yueqing Xie ◽  
Fan Song ◽  
Yaqiang Wei ◽  
...  

Author(s):  
Nasi Mou ◽  
Poh Seng Lee ◽  
Saif A. Khan

In this paper, a simplified ‘effective circuit’ fluid flow model is proposed to complement full-domain (geometry based) simulations of fluid flow in novel discrete oblique fin heat sinks. In the proposed model, the discrete flow paths are modeled as effective resistances, and the intersections between discrete flow paths are modeled as ‘nodes’. In an electrical circuit, the current of each branch can be derived from the current division rule, and hence the actual flow rates in the effective circuit are determined by the effective resistances. Simulink R2011b, a graphical extension to MATLAB for modeling and simulation of systems, is chosen to construct the equivalent circuit. The effective resistances are calculated using the well-known friction factor expressions for laminar flow in micro-channels. A full-domain geometry-based simulation is performed on CFX 14.0 serving as a benchmark for the developed ‘effective circuit’ fluid flow model. The results show that for a given total current value and mass flow rate, the difference of pressure drop over the whole heat sink between the simplified flow model and CFX simulation is within 13%. The mass flow distributions obtained from the simplified flow model and the CFX simulation exhibit a common distribution pattern. Interestingly, the simplified flow model is even able to capture flow migration — a distinctive phenomenon of flow in oblique fin geometries. We thus confirm the feasibility of the method of construction of our simplified ‘effective circuit’ fluid flow model.


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