Questions tagged [hydrogeology]

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How are aquifers found and traced?

Recently a line from a news article about an aquifer in the path of a tunnel boring machine for Metro networks caught my attention: Ahead of tunnelling, the builders conduct hydrogeology, a study ...
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1answer
57 views

How does friction and radiolysis provide hydrogen for “unusual types of methane”?

The fascinating New York Times article Gas That Makes a Mountain Breathe Fire Is Turning Up Around the World talks about the Flames of Chimaera and the Deep Carbon Observatory: And a series of ...
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1answer
93 views

How acidic waters make rocks disappear?

I was working on this science project. I was on step 11, day. 4. Since day 2, I found out that my pH and the mass of the rock (limestone) stopped changing. This project should proves acidic water ...
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What is the generic term used for sensors that measure soil water tension?

Tensiometers are instruments used in measuring soil water matric potential (vadose zone water tension) by measuring the vacuum in a water-filled tube that contacts the soil through a porous cup: ...
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The DRASTIC groundwater vulnerability model and it's relevance today

I am reading a groundwater pollution vulnerability study by Mark Angle of the Ohio Dpet. of Natural Resources (ODNR) for my county. The model used to assess the groundwater vulnerability for the ...
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1answer
66 views

How do we detect floods?

How do we know that there was a flood at a certain place at a certain time. For example if there was a flood in place A 200 years ago. How could we detect it?
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36 views

Minimum Surface Water for Plate Tectonics?

There is good evidence that the presence of water on a planet's surface is necessary for that planet to have plate tectonics. My question is this: Do we know if there is a minimum amount of surface ...
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1answer
104 views

Hydrology - Flowrate vs. radius of influence

I am using the following equation (Theim/Dupuit) to determine radius of influence for an unconfined aquifer. Assume all other variables are held constant. If Q increases, does the Radius of ...
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1answer
502 views

Concept of artesian aquifers and pressure is not clear.

I do not understand how the Artesian aquifer is causing the water in the flowing well to reach a level higher than the ground surface? And what role does the piezometric surface play in it?
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2answers
294 views

What is serpentinization, in the context of disappearance of surface water on Mars?

The recent paper in Nature The divergent fates of primitive hydrospheric water on Earth and Mars (Nature 552, 391–394 (21 December 2017) doi:10.1038/nature25031) has been linked by many recent news ...
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133 views

Where on Earth does paleo-groundwater exist?

Where on Earth do we expect to find very old groundwater (infiltrated thousands of years ago)?
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1answer
242 views

What is difference between partially penetrating stream and fully penetrating stream?

If fully penetrating stream means, the stream penetrates fully to the depth of aquifer, then doesn't it mean that there is zero conductance or leakance? The leakance or conductance is a term used to ...
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3answers
1k views

What is meant by inverted water table?

There are some papers in literature which discuss stream-aquifer interaction. They describe that the stream aquifer interaction ranges from connection to disconnection. When there is disconnection, ...
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What forms do groundwater flow equations have when Dupuit supposition is not considered?

Near pumping wells or near/beneath a stream, the groundwater flow is not totally horizontal and the vertical component of groundwater movement at these points cannot be ignored in reality. Often, ...
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1answer
185 views

Coupling recharge with 1D groundwater flow model

Suppose we are modeling 1D groundwater flow in an aquifer of extent $x$ from $A(x=0)$ to $C$. Lets say for unsteady state conditions, the input is at $A(x=0)$, we can model piezometeric response at $B ...
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134 views

Calculate Total stress

I'm looking to calculate the total stress at a depth of 10 km in a rock column, where porosity varies with depth. I believe I can figure this out, however I might have copied down an equation wrong. ...
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599 views

How far can water wick up above the capillary fringe in sediment or soil?

The capillary fringe is the area above the water table where the water is held in tension so that the connected pore space is completely saturated, although variation in pore size means that there is ...
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1answer
135 views

comparing use of Laplace equation with diffusion equation to simulate flow of fluid/water through porous media?

What is the difference in using Laplace equation (say only in 1D) to simulate water flow in a porous media with that of using diffusion equation for same purpose?
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1answer
995 views

Why confined aquifers have low storage?

Identical drop in head in unconfined and confined aquifers releases different amounts of water. The confined aquifer releases less water and thus has less specific storage. When both aquifers are ...
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1answer
585 views

The rock that gives birth to quartz sand

Thanks to one minute of the Earth we know that beach sand mother rock, besides the quartz itself, is (or was?) made of olivine, amphibole and orthoclase. I wonder, what is the name of that rock and ...
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What field data do I need for the Green-Ampt infiltration Model?

I want to estimate infiltration in a soil. What kind of parameters should I be measuring in the field?
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Link between different ways of modeling permeability

The most famous equation describing the permeability $k$ of a soil is the Kozeny-Carman equation: $$k = \frac{\phi}{8}r^2 \approx \frac{\phi}{c}\left(\frac{V}{S}\right)^2$$ $\phi$: porosity V: pore ...
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1answer
386 views

Why is fluid pressure in a fractured rock reservoir only dependent on hydrostatic pressure?

Why does lithostatic pressure not play a role? (or does it?)
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Could a massive flood have formed the Grand Canyon?

I believe that the accepted theory for how Arizona's Grand Canyon was formed was that erosion caused by the Colorado River flowing through the area over millions of years was the force at work. Yet ...
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How to integrate dry wells into groundwater level mapping automatically (inequality constraints on the interpolation)?

I'm interested in automating spatial interpolation of groundwater level measurements. I'm wondering if anyone knows a method for automatically taking into account things like dry wells, where I can't ...
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1answer
260 views

How to characterize flow of nonreactive tracer in a porous media?

About Tracer Experiment This experiment is conducted by injecting a fluid with nonreactive species of certain concentration inside a column or core composed of sand. The injection of fluid can either ...
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1answer
145 views

Unrealistic solution for advection-diffusion-reaction PDE with heterogeneous porous media

About the code: I have a code which simulates concentration from advection-diffusion-reaction PDE in 2D space (X,Y) with time. The solution is obtained using fully implicit finite-difference method ...