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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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Literature in hydrological modelling

I'm looking for good introductory literature in hydrological modelling. My aim is to understand in depth different flow algorithms, Any recommendations?
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Source of water for the Great Artesian Basin in Australia

The Great Artesian Basin in Australia covers 23% of the continent and contains 64,900 cubic kilometres of water. Many years ago it was claimed on a TV science show I saw that some of the water in the ...
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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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What is hydraulic diffusivity?

I'm having trouble grasping which properties of the soil are described by hydraulic diffusivity (sometimes referred to as soil-moisture diffusivity which is based on the diffusion equation). What ...
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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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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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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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51 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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52 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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Chloride and evaporation

I have a layered aquifer with water that contains high concentrations of calcium and sulfate (~400 mg/L Ca2+, ~1300 mg/L SO42-), at 50 cm below ground surface (bgs), 250 cm bgs and 300 cm bgs. The ...
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If water is a renewable resource, why is there water scarcity?

Water is a renewable resource, renewed by the water cycle. If we use water too quickly, water should get evaporated and come down again as precipitation. So, Why is there water scarcity if water ...
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Are there any saltwater rivers on Earth?

I'm curious if there are any saltwater rivers on Earth. These would presumably arise if a saltwater lake had a river outlet to the ocean. However, all the saltwater lakes I looked at (Caspian Sea, ...
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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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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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What keeps water from sinking into earth?

I remember reading somewhere that there's evidence of water on Mars but it all sank into the Martian soil. So what prevents that happening on earth? Some people say it's because the crust is not ...
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1answer
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Where does the Amazon River really begin?

Where is the true source of the River Amazon? Searching Wikipedia, it suggests the River Apurímac has traditionally been considered the source. However, Google says it is the River Mantaro. In other ...
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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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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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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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water (or hydrological) year around the world, does it change?

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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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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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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1answer
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How long does it take to refresh the entire water supply in the Earth's atmosphere?

Water in the atmosphere is present as vapour, liquid and ice. It is just a small amount of the Earth's total water supply. I'm wondering how long it will take to rain down all the water from the ...
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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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395 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
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Is there a special name for along-course elevation profiles of rivers, and where you can you find them?

Was discussing the terrain and rivers of Europe today with my father and it became apparent that a graph of the elevation versus course of a river would offer interesting insight, including a quick ...
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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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3answers
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How does a meandering river form?

I read this explanation about rivers: "As the river erodes laterally, to the right side then the left side, it forms large bends, and then horseshoe-like loops called meanders" Why does the river ...
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1answer
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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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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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Is there a method to determine the point rainfall intensity for small catchments?

I need to design a weir for a small earth dam in an arid area with a small (smaller than 200 ha), fairly flat catchment area in southern Africa. The idea behind the dam is to collect not more than 10 ...
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How and why do these tree-like river structures form?

I noticed these detailed tree-like river structures in Google Earth Google Maps link How and why do these form? Rivers don't typically split. What would cause the water to keep branching off again ...
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Math needed for Hydrology, specifically surface water hydrology

I wanted to know what math is needed for hydrology, in particular surface water hydrology. In my research online, of Master's programs (either in Hydrology or Environmental Science with a ...
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2answers
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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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2answers
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Time of concentration - Difference between large and small basins

I am looking for any academic reference (i.e. articles) regarding the time of concentration for large and small basins. E.g. I would expect that a large basin (area > 1,500 km^2) will flood (or reach ...
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Minimum flow duration curves

It is common to prepare flow duration curves from a set of daily river flow data, but does it make sense to build a flow duration curve from a set of monthly minimum flow data? I searched on internet, ...
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Does a hurricane classification exists where estimated rainfall is taken into account?

Hurricanes are classified with the Saffir–Simpson hurricane wind scale. However an extreme amount of rainfall can cause a disaster although the windspeeds are not extreme. Is there some sort of ...
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1answer
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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
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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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602 views

Rivers flowing into Pakistan

Why do Rivers flowing into Pakistan come from either Afghanistan or India and not from inland mountains? Is it possible for Pakistan to source fresh water from its northern mountains avoiding India ...
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2answers
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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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How to determine associated USGS stream gauges with a watershed HUC?

USGS stream gauges have an associated drainage area, but the associated hydrologic unit listed by USGS is often different than the actual drainage area. How can one determine what hydrologic unit ...
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1answer
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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
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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 ...
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2answers
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Does nitrate take a particular long time to percolate from surface into groundwater?

In a recent discussion with a farmer, the (at least in northwestern Germany) "popular" topic of nitrate infiltration into groundwater came up. The general view is that lots of fields receive more ...
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1answer
287 views

Area reduction factor reference for precipitation

For a large catchment (>1000ha) I'm looking for some method to use a area reduction factor to adapt precipitation values. I have a large dataset of daily precipitation values but I have to use some ...