Questions tagged [hydrology]

Hydrology is the study of the properties and behaviour of water. It concerns both surface as well as subsurface water, although water in the oceans and atmosphere is generally excluded. Those are studied by oceanography and meteorology, respectively.

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How to transfer surface roughness from the unit mm into Strickler coefficient m1/3 per second

I have a hydrodynamic model to simulate flash floods. This model expects roughness data in the Strickler coefficient format (kst) in the unit m1/3 per second. I got a table with roughness values I'm ...
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+50

Modeling the total water inflow across multiple reservoirs

I'm new to hydrology and I have a question regarding the modeling of multiple reservoirs. I need to estimate the total water inflow to multiple reservoirs that will be observed tomorrow, conditional ...
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How to choose “relevant” precipitation durations for flash flood modelling?

For my thesis, I model flash floods in urban areas. A book with recommended practices says to use events with a recurrence interval of 30 and 50 years. Regarding the duration of the precipitation ...
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Rainfall guage stations outside the watershed

How can I determine the rainfall depth for an event over the watershed, if I just have two stations, S1 and S2, that are outside the catchment? Methods I have thought of were to take the average of ...
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struggling to find a good research question in rainfall runoff modelling [duplicate]

I'm writing my thesis on modelling extreme rainfall and I'm still struggling to find a good research question. I have asked a similar question before in this post. Maybe you guys can give me some ...
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How much water will flow into the Caspian Sea if it is connected to the World Ocean?

I wonder how much benefit would a hydroelectrical project built on this inflow bring. There are projects to fill up the Erie, Salton, Qattara and the Dead Sea. But for the Caspian, there is only a ...
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how does model validation work? What is needed for an appropriate validation

I have an 2D hydrodynamic model in a approx. 10km² catchment and one rain event that goes one hour with measurements in a 5min interval. The reccurance interval for an event like that is close to ...
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1answer
65 views

If the top layer of a large river freezes, is the remainder's rate of flow affected?

This question is a hypothetical, and has to do with the notion of cheap, modular turbines that can be sunk and anchored to a specific depth in a body of water. Each would not generate much power, but ...
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hydrologic vs. hydrodynamic modelling of surface runoff

In the description of a Software it says that it computes the net rainfall, runoff formation and runoffconcentration on a surface hydrologically. With an extra module, the runoff formation can also be ...
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1answer
50 views

research question for modelling extreme rainfall event with coupled 2D surface and 1D sewersystem model

I would like to write my thesis on modelling extreme rainfall events in urban areas coupling a 2D surface model with an 1D sewer channel model. I have access to a good software which models ...
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1answer
62 views

How to check the recurrence intervall of heavy rain events

Heavy rain or flood events have recurrence intervalls. I.e. 100 year, 50 year or 25 year events. However, with increasing data and global warming and other factors these intervalls change. How can I ...
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How do oases form in the middle of the desert?

I am wondering if there are any theories about the formation of oases, and I am also curious about why an oasis can even last for a very long period of time. I have heard that fresh water exists on ...
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what is a sensitivity analysis in heavy rain 2D surface / 1D drainage network models

For my thesis, the lecturer proposed to make a "sensitivity analysis" with a 2D surface model connected with a 1D drainage Network model for a storm rain event. However, I'm having problems to figure ...
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formula to convert precipitation in mm/h to runoff in m³/s

I have precipitation data in mm/h but to use them for my model I need them in m³/s. Is there a formula to convert them?
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1answer
22 views

Modelling extreme rainfall events: 'blanket approches' when considering soil infiltration

For my thesis on modelling an extreme rainfall event with a 2D surface runoff model I'm supposed to consider the effect of soil infiltration on the runoff: In my work description it says I'm supposed ...
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Do dams reduce the flow of river downstream?

There is a conflict between Egypt and Ethiopia, because the latter wants to build a dam on the Nile river. Citing this article: [Egypt] fears the Nile dam will reduce its share of the river and ...
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2answers
103 views

Loop in the continental divide

Various maps of the Continental Divide (the hydrological feature, not the trail) contain a loop that looks like this: What is the hydrologic meaning of the loop in Wyoming? Even if it's a basin, ...
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Avra valley aquifier region boundary

Attached is an image of the Avra valley in Southern Arizona, USA from Effects of Kriging and Inverse Modelling on Conditional Simulation of the Avra Valley Aquifier in Southern Arizona -- Clifton and ...
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2answers
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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
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Run Hydrus-1D from the command line

Hydrus-1D, is a modeling environment for analysis of water flow and solute transport in variably saturated porous media. This program has a graphical environment which works very well, however a lot ...
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What does a “closed basin” mean in groundwater terms?

This answer talks about a "closed basin" that has an outflow to the sea. I had previously assumed that "closed basin" meant the same as "endorheic basin", but that is obviously not the case. What is ...
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1answer
47 views

How to recharge ground water directly from river water

I am not sure if I am asking it on a correct platform or not. A rainy river passes through my village. We suffer both in summer and in rainy seasons due to this. Could anyone explain how to recharge ...
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1answer
109 views

Code for DEM based flow routing in R

I have a DEM as shown for which I have determined flow paths using D8 algorithm (My own code) in R. The resulting DEM with the flow paths is also shown. The flow paths are generated in the form of ...
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Can I interpolate rainfall data from stations outside of watershed for the watershed?

I have only few station inside the watershed so I want to use the stations outside if I can to get better results
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Flood and Statistics

A recent flood was due to combined effect of rainfall(precipitation) and reservoir storage. I have daily rainfall data and reservoir storage data. How can I correlate these two to get a statistical ...
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1answer
145 views

Hydrology- flow accumulation

I'm not specialist in hydrology, and I would be very grateful if you answer my question: What is flow accumulation in hydrology? Why algorithms used to calculate it over a raster DEM don't take ...
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1answer
98 views

What effect does concretization (paving/flooring with concrete) has on ground water table

I am a newbie for hydrology. If the question seems to have "well known answer", I appreciate if you point me to the resources. I will add details to the question based on comments. Consider a town of ...
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1answer
43 views

What would be a reasonable set of thresholds for flood severity classes?

When working with extreme hydro-meteorological events, flood in particular, it is common procedure to classify each event by its return period/recurrence interval. This probabilistic measure has the ...
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Is there an approximate rate for water temperature by depth that could be modeled simply?

I know that there are a couple of questions covering latitude and longitude for water temperature, but overall I'm more interested in the rate of temperature change by depth. Thought Process: ...
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How is it possible to use up the water in a region?

The Dead Sea, rivers in California and the Aral Sea are said to be shrinking due to water usage, e.g. for agriculture. Yet the water must go somewhere. After the fields are irrigated, the water ...
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2answers
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In winter, is pond water warmer with or without a fountain? I have goldfish [closed]

I know that goldfish can hibernate but I'd like to keep the water warmer for them. Is moving water colder or warmer than still water? The water shoots out of "pipes" about 3" above the water's ...
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2answers
565 views

Are the water year/hydrological year different around the world?

Following the commonly-known USGS definition of Water Year (or Hydrological Year) we know that it starts on the 1st October and ends on the next 30th September. Is this definition valid only for ...
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When will the weight of melted polar ice release the (currently stuck) subduction of the oceanic plate West of the Oregon coast?

Melted polar ice water makes the oceans deeper on average. The extra water on top of the oceanic plates makes them sink relative to the continental plates. This relative vertical displacement will ...
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1answer
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How to obtain the correlation between monthly streamflows based on physical concepts?

I've been tasked with generating synthetic streamflow scenarios through disaggregation. First, I will generate 50 years of streamflow data. For that, I will probably use a simple model as AR(1) or an ...
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Environmenal flow in the context of global gridded hydrological analyses

Environmental flow (EF) is a widely used concept in river basin management and river ecology. There are more than 200 methods to estimate the flow that should be left to the rivers to ensure a ...
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1answer
668 views

Why do we consider hydrostatic pressure and lithostatic pressure separately?

In petroleum geology, why do we consider hydrostatic pressure and lithostatic pressure separately? Surely the pressure at any point, whether fluid or rock, at depth is simply equal the weight of all ...
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1answer
44 views

Do desalination plants affect the ground water table?

I saw an article recently in the newspaper stating that a desalination plant near the seashore was causing the ground water to become saline. Usually I would expect that areas where saline water ...
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What's the difference between “loading” and “receiving” in water quality modeling?

I see some models described as simulating 'receiving water quality' and others as 'pollutant loading' models. What is the difference between loading and receiving models in this context? I am more ...
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1answer
697 views

Rivers - How to calculate maximum velocity from average velocity in a cross section

I'm studying flow velocities in a small river. I have a lot of data of average flow velocities in cross sections throughout the entire catchment. And I know the river develop a stream velocity profile ...
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1answer
104 views

Rocks sparking under water

I have searched for an answer to this question for years, to verify if it was true. A man that lived on a river in the rugged part of the northern Washington Cascades told me an interesting story. He ...
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1answer
81 views

How did the Rhine originally look like? (before human intervention)

For personal reasons I decided to examine the shape and formation of the Rhine. Unfortunately though, the Rhine has long been diverted from its original course by human intervention, so I tried to ...
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1answer
60 views

Does the configuration of a confined layer change the storage?

I have a confined aquifer of sand. I will temporarily drain the aquifer, remove the top one meter of the aquifer and then replace that with a layer of gravel. After that I will restore the layer (and ...
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1answer
259 views

Lake outflow forming a “reverse delta”?

While rivers often form a delta when they flow into a lake, the outflow of a lake is usually a single stream. Are there lakes where the water flows off in multiple channels that merge into a single ...
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Is it possible to create clouds by pumping water into volcanoes?

Suddenly, there is this idea in my mind that if an important effect of global warming is rainfall reduction and drought, is it possible to use volcanoes as water vaporizers (regardless of costs)?
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2answers
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Searching for ground water

I would like to attempt to build a well-type structure in a woodland area. This woodland is mainly inhabited with Silver Birch and Sycamores and there is a shallow stream running down off of a ...
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2answers
169 views

Comparing Pros and Cons of SWAT and HSPF

To model hydrology in a watershed, two of the most famous and widely used distributed models are SWAT and HSPF. I have some good understanding of HPSF, but I don't know when and why should one prefer ...
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1answer
116 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
213 views

Clarification of overbank flows

Apologies for what may be a very basic question, but I am struggling to understand the definition of overbank flow. Overbank flow is defined along the lines of this: Water flow over the top of the ...
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1answer
84 views

how to know the correct results in watershed delineation in ArcGIS?

When I use one DEM in my study area to delineate watersheds, the results are different from when I mosaic 4 DEM layers adjacent to each other. After the mosaic process, 3 of the basins were merged in ...
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1answer
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What's the difference between these most basic, first-order models for estimating runoff?

There are a lot of variations of basic, first-order hydrology models to estimate runoff from rainfall with a few other parameters. From what I can tell, most very basic rainfall-runoff models use one ...