# Tag Info

44

The Okavango River is a good example of this. It drains into a swampy delta in the middle of the Kalahari desert: The Okavango Delta, CC BY Justin Hall.

34

The Colorado River frequently fails to reach the Gulf of California, mostly due to diversion to agricultural and metropolitan uses upstream. This National Geographic post from 2014 elaborates on the Colorado River reaching the sea for the first time in 16 years: This reunion between river and sea is due to an agreement between Mexico and the United States, ...

27

The concepts you are looking for are two categories of drainage basins, endhoreic basins and cryptorheic basins. Endhoreic basins are drainage basins that do not drain to the oceans, either above ground or below. The rivers in an endhoreic basin flow toward a local low spot. In some places these low spots are permanently covered by water. Examples includes ...

25

There are rivers that don't flow into seas or lakes if you consider influent rivers. Which are rivers that loose water to the ground (seeps into aquifers). For example "big lost river" of Idaho, which feeds into the Snake river aquifer. In regards to evaporation, it depends on what you consider a river. Because water flowing through a tiny little ...

14

tl;dr: no. Long answer: First of all, like mentioned by others in the comments, you would need some physical mechanism to take a whole lot of water, evaporate it, and drop it at once at a place where the Grand Canyon is now. This is not something that's going to happen because of physics. If there was some extraordinary event which could have caused this, ...

8

In addition to all of the above there are meanders inn the Grand Canyon which are hydraulic outcomes of 'minimum energy flow configurations'. This constrains the discharge rates that are possible - to within the normal range of hydrologic discharges. Furthermore there are several places in the Grand Canyon where there is clear evidence of the river having ...

6

The red line or piezometric line is the level to which the water wants to rise - if it were allowed to reach hydrostatic equilibrium. Artesian conditions are anywhere where a confined aquifer sits below the hydraulic head level (the level to which the water wants to rise). In this case the water is confined and cannot reach the water table even though it ...

6

does serpentinization just refer to the formation of some hydrated minerals that happen to be of a class that is historically been referred to as serpentinite or it's subgroup Yes. In simple terms, the reaction is enstatite + forsterite + water = serpentine. MgSiO3 + Mg2SiO4 + 2H2O = Mg3Si2O5(OH)4 Forsterite and enstatite (or more generally, olivine and ...

6

Just locally to me, there are the Carson and Humboldt rivers, which drain into sinks of those names - the Carson Sink and the Humboldt Sink. There's also the Quinn River, which drains into the Black Rock desert when it has water in it, which it doesn't always. There are many smaller rivers & creeks that do this. For instance, a lot of smaller creeks on ...

6

A must-to-mention is Amu Darya. It was once flowing to Aral sea, but since ~1950s the water has been used for irrigation, and now its waters do not reach the sea. (And as a result, there it little that remains of the sea.)

5

The Luni River of India does not meet any sea, ocean, lake, or any other body of water. Most Indian rivers meet larger rivers or flow into the Bay of Bengal or the Arabian sea. This river starts at an elevation of 772 meters from the Naga Hills of Aravalli in the Ajmer district of Rajasthan. The distance covers about 495 km, and the river meets its end in ...

5

Serpentinization is a system of, chemical reactions which convert anhydrous ferromagnesian silicate minerals (pyroxene, olivine) into hydrous silicate minerals (serpentine) plus some other possibilities like brucite and magnetite. Brucite forms if the precursor rocks are rich in magnesium (dunite, for example). Magnetite forms if there is enough iron ...

5

An Inverted or Perched water table is a water table that is above the main or regional water table in an unconfined aquifer. The perched water table is generally above a layer of low permeability material such as clay. In the image below, notice that there is an "inverted" water table along bottom of the perched water table.

5

In any solution to a PDE, whether analytical or numerical, you will always need as many BCs as the number of derivative steps. For examples: $$dY/dt = k Y$$ needs one BC while $$\partial Y/\partial t = k \nabla^2 Y$$ needs three BCs. The second case is germane to your problem. You will need one BC on time $t$ because one derivative is on time. You will need ...

4

I assume you mean sensors that measure volumetric soil water content. The answer will depend on the amount of precipitation and the permeability of the soil. Soils don't reach full saturation in some climates - especially coarse texture soils. I would say that if the soil water content reaches a maximum value that persists for a period of time after large ...

4

Aquifers are relatively permeable zones of material that transmit water. Common aquifer materials include layers of unconsolidated sedimentary rock, like sands and gravels; and poorly cemented “bedrock” units like sandstone. Interconnected solution cavities in limestone, called karst, are common in some areas. Calling something an “aquifer” generally infers ...

4

In only one minute of presentation there isn't time for detailed discussion, so one has to make broad generalizations which, on closer inspection, aren't quite true. It is true that most sand is made of quartz, and that most of this quartz arises from weathered granitic rocks, of which the main minerals are quartz, orthoclase and plagioclase, usually with ...

2

It's not clear exactly what is being modelled here, but it seems to me that there are two ways in which the concentration can 'go negative'. Firstly, the rate of change of concentration can be massive, in which case see what happens when modelling with much smaller time steps. Or, the diffusion term substantially exceeds the advection term, which is ...

2

Fluid (or 'pore') pressure does not depend only on hydrostatic pressure — it also depends on stratigraphy, fluid content, and the geological history of the rock. The fluid 'stack' can be thought of as a (mostly) connected body of fluid — dominantly brine and hydrocarbons. The rock 'stack' is a similarly interconnected body. The fluid stack defines a typical ...

2

If you are not interested in the vertical flow occurring in your aquifer (which I assume is the case) then one can indeed add the recharge to the existing head! In groundwater issues, we often assume the recharge to be constant over time and equal over distances when considering such problems. This is mainly due to simplification as we are often interested ...

2

The Laplace equation, (d^2 Ψ)/(dx^2 )+(d^2 Ψ)/(dy^2 )+(d^2 Ψ)/(dz^2 )=0, is just a steady state 3D flow equation. It's a black box conservation of hydraulic potential. Diffusion doesn't come into it. The Diffusion equation (assuming homogeneous isotropic conditions) is (∂^2 Ψ)/(∂x^2)+(∂^2Ψ)/(∂y^2)+(∂^2 Ψ)/(∂z^2)= S_s/K ∂h/∂t. This discretizes the time ...

2

I think your confusion is because you are keeping the head fixed. As you increase Q at fixed T the drawdown curve will become steeper when r1, h1, and h2 are fixed. That means r2 will move towards the pumping well.

2

Locally to me, the Nailbourne rises at a spring in the small town of Lyminge, in the Kent Downs, and then sinks back into the ground shortly after passing through the village of Elham (except in a very wet winter when groundwater levels rise enough for it to stay above ground). You might choose to disqualify it because it does resurface lower down the ...

2

Fundamentally it doesn't make sense to describe the point scale model with hillslope length and drainage density. If you are looking to model a soil column, you could use Darcy's law or Richard's equation. If you are looking to model the catchment, the point scale is not appropriate, although you could always incorporate those point-scale appropriate ...

1

Virtually every oil / gas well contains old water. However , surface water , mixed with produced water, is injected in some to facilitate production .Last number I saw was that onshore wells in the US averaged 90 % water in the liquid phases.

1

In large intracontinental basins where the main rock formations are exposed in adjoining highlands and rare deeply buried within the basin itself. The Madison Limestone is an example. The Madison and its equivalent strata extend from the Black Hills of western South Dakota to western Montana and eastern Idaho, and from the Canada–United States border to ...

1

Streams that are shallow relative to the thickness of the aquifer in which they lie. Such streams often are referred to in the literature as partially penetrating streams. Most streams are partially penetrating streams. Seepage between a partially penetrating stream and the contiguous aquifer occurs both horizontally and vertically through streambank and ...

1

To amplify on Gary's answer for the situation under a stream: Surface water will be connected to an unconfined groundwater aquifer if the sediments are saturated between the aquifer and the stream. If the head (the elevation of the water i.e. its pressure) is lower at the stream than the adjacent sediments, then it will be a "gaining stream" the water in the ...

1

Aquifers are detected by boreholes or by water divining. Water divining is a very unscientific method which so far has no rational explanation, yet is often successful. I put this down to the fact that Britain is such a wet country that wherever you drill a borehole you are almost bound to discover water sooner or later. Perhaps a more scientific explanation ...

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