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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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Modelling the unsaturated zone in FeFlow in seawater intrusion scenarios

Does anyone have experience with modelling seawater intrusion scenarios in Feflow? In my models, my mass-concentration seems to drive up into the unsaturated vadose zone, which I don't believe is ...
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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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Designing FIR or other filters for soil water content

I have 250 or so soil sensors that I need to QC. They monitor various parameters such as soil temp, soil water content, soil co2, and soil heat flux. It isn't unusual for a sensor to behave poorly due ...
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1answer
132 views

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
81 views

Are there ways stormwater attenuation can be quantified for comparison between different systems or conditions?

Various sources agree land cover changes impact the attenuation of stormwater. E.g. forest areas generally slow the rainfall-runoff response and moderate it, reducing peaks in hydrographs, as compared ...
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1answer
86 views

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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1answer
289 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 ...
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61 views

Are ramp pumps the solution to the global water problem? [closed]

For the past few years people have been trying to solve the global water problem (especially in Africa), and what better way than being echo friendly. So my question is, can you use the tidal energy ...
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2answers
928 views

Does negative reference evapotranspiration make sense using FAO Penman-Monteith equation?

I computed the daily reference evapotranspiration $ET_0$ using the Crop evapotranspiration - Guidelines for computing crop water requirements - FAO Irrigation and drainage paper 56. The outputs seems ...
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1answer
424 views

Hydrology - Depression cone VS transmissivity

My question concerns the depression cone of a pumping well in a confined aquifer: Say the transmissivity of the aquifer is 1200 m^2/day how will the cone change if the transmissivity is 600 m^2/day? ...
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1answer
260 views

To delineate the drainage basin for a lake, would the pour point be the inlet or the outlet?

I am interested in the area draining into and affecting a particular lake. Delineating this drainage basin, should I use the lake's inlet or outlet to best capture the relevant drainage basin? I think ...
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1answer
175 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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962 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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1answer
56 views

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
167 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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Linear Boussinesq Equation for groundwater flow in inconfined aquifer?

I was reading a paper (equation 1 in linked paper) where they used 'linearized Boussinesq' equation to model groundwater in unconfined aquifer. The linearized Boussinesq equation described in the ...
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3answers
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Accepting/refusing high rainfall measurement

I have a series of records of annual maximum daily rainfall for a station for about 80 years (1935-2014). Only one value is very high compared with the others, but in this year, the other close rain-...
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What field studies have developed or supported the Penman-Monteith equations for estimating evapotranspiration?

I'm trying to understand transpiration estimation methods. The FAO recommends a standard Penman-Monteith methodology for modeling evapotranspiration based on meteorological and vegetation parameters (...
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1answer
884 views

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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1answer
111 views

Do Hydro-Carbon extraction units pollute ground water?

I am from India, Tamilnadu state. Our nation has planned to have hydrocarbon extraction units in our Thanjavur villages. We, a 70 million people Tamilnadu state get most of our rice from that region. ...
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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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1answer
94 views

Is there a quick way to roughly estimate how quickly a flood will move downstream?

At the time of this post, there was urgent danger of spillway failure at the Oroville Dam in California, with evacuations in place for hundreds of thousands, and even larger populations further ...
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Capillary rise experiment and obtainable information about the porous medium

I have access to rock core(s) and vacuum saturation chambers as seen in the image below. I can dry the rock core using an oven, measure its geometry and mass. I can place it into the vacuum ...
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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
45 views

Different peak and mininum discharge times for Newfoundland rivers

I have been studying the Humber, Gander and Terra Nova rivers in Newfoundland. I have been given a table of discharges, and for the peak discharges I see: Gander: around April and May (rougly from ...
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2answers
120 views

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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2answers
53 views

Is it possible to have an AR(0) for streamflow?

Autoregressive models (AR) are extensively used to understand the behavior of streamflow. The literature abounds with examples of AR models from different families applied "everywhere" to fully ...
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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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1answer
129 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
916 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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0answers
31 views

Is there a way to calculate difference initial water content, from curve number method?

I want to calculate difference between initial water content of a soil given that its saturation water content can be found from its type. Is there a way to find initial water content of that soil ...
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0answers
38 views

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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1answer
195 views

What is the source of the Big Sur river?

While hiking in the Ventana Wilderness in Big Sur, Calfornia, I kept trying to figure out one question: what is the source of the Big Sur river? Wikipedia reports its tributaries being the Redwood ...
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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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Averaging watershed areas

If I am looking at different USGS stream gages, calculating their 90th percentile streamflow, and then doing a weighted average of the 90th percentile of the streamflows using the watershed areas - ...
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208 views

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
191 views

What divides Hydrological Unit Code areas of the same level?

I'm trying to better understand the Hydrological Unit Code (HUC) system of the United States. I understand the basic hierarchy of it (HUC4, 6, 8, 12) and watersheds/drainage areas. Here's what I want ...
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2answers
9k views

How much time does water takes to reach to the ground?

I want to understand the phenomena where water droplets after precipitation reaches to the ground. How much time does it take to become ground water or in other words how much time is taken by water ...
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1answer
84 views

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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1answer
312 views

Cooling effect by evaporation [closed]

Why exactly does water cool down by evaporation? What happens in this process? How much does it cool down? What's the formula to describe this process?
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Any way to increase the amount of water that flows through bedrock?

My pond is fed by a spring that collects inside a large concrete box (6' x 6' x 8'deep) that was formed up many years ago. The walls of this box are sitting on bedrock. Small trickles of water seep ...
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272 views

What is difference between Riverbed conductance term and streambed leakance/retardation coefficient?

In literature some times to account for semi-pervious sediments at bottom of stream, streambed leakance also called retardation coefficient ($L$) is used. This is equal to the ratio of conductivity of ...
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4answers
5k views

Why do rivers have 'wells' in mountains?

Why/how can rivers have sources in places high above the sea level?
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1answer
133 views

In -20 °C weather, creeks below waterfalls here form ice columns. What are these called? Ice-canoes?

I would like to know the name(s) of this ice formation. How common or rare is it? What other regions of the world does this occur in? What specific requirements are needed to produce it and could it ...
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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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53 views

Near Future Precipitation and Temperature estimations?

I was wondering if anyone here is familiar with temperature and precipitation estimation? I need to estimate P and T from April to July 2016. I am planning to use excel to do the calculation because ...
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1answer
222 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
138 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 ...
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1answer
235 views

How are biological oxygen demand and depth related?

What is the relation between biological oxygen demand (BOD) and depth? I need to calculate the BOD of a drinking water tank and I have ultimate BOD at the surface of water, but I need to calculate it ...
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1answer
221 views

In hydrology, what's the difference between specific and total catchment area?

I am getting stuck on the concepts of Total Catchment Area (TCA) and Specific Catchment Area (SCA) as I try to learn more about TOPMODEL and hydrology modeling. What do these metrics mean in hydrology?...