Science topics: HydrologyHydrologic and Water Resource Modeling and Simulation

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# Hydrologic and Water Resource Modeling and Simulation - Science topic

Hydrologic and Water Resource Modeling and Simulation is a streamflow measurement and modelling, methods and research.

Questions related to Hydrologic and Water Resource Modeling and Simulation

There are many commonly used methods for esimtation of evapotranspiration which are based on temperature, radiation, mass and energy transfer etc. or a compbination of thse. Methods such as Penman-Monetieth, Pendman, Hargreaves, Priestley-Taylor, Thronthwaite etc. fall under these categories. What I want to know is the applicability of these methods primarily based on the climatic conditions of the area. Like whichmethod is suitable for humid conditions or arid climate? If someone asks me what method should I use to estimate the ETo for an area in Mumbai, which method should I use?

Hello,

I am using MODFLOW 6 transient simulation and have the following listing file. I wonder about two of the outputs. See attached screenshot.

- What those STO-SS & STO-SY mean? Are these total available water in storage? is it change in storage? If so, what is the difference between in and out?
- What is the meaning of positive recharge in the recharge package (RCH) in the out section? I would have expected it to be equal to zero.

I will appreciate your response.

Greeting.. suppose i'm missing continuous half hourly water table data for extended period (say a month) due to instrumentation failure, can I fill the gap using a nearby monitoring station that, from long term observation, seemingly share the same trend/fluctuation? which model is recommended that uses adjacent water table data as input? Personally, I was thinking along the route of using artificial neural network

(Matlab, R, Python, ...??)

taking into account the current evolution of artificial intelligence

I have received data for 50+ rainfall stations in my study area. Is there any mathematical formulae which gives optimum number of rainfall stations for trend based climate change study ? All of them have missing values in them, ranging from 1% to 50%. Upto what percentage of missing values can be filled by statistical methods and how to determine the threshold limit (whether 10% or 15% or 20%). If any literature is available on this, kindly intimate me

Four homogeneity tests, namely the Standard Normal Homogeneity Test(SNHT), Buishand Range(BR) and Pettitt test and Von-Neumann Ratio test (VNR) are applied for finding the break-point. Out of which SNHT, BR and Pettitt give the timestamp at which the break occurs whereas VNR measures the amount of inhomogeneity. Multiple papers have made the claim that "

*SNHT finds the break point at the beginning and end of the series whereas BR & Pettitt test finds the break point at the middle of the series."*Is there any mathematical proof behind that claim ? Is there any peer-reviewed work (Journal article) which has proved the claim or is there any paper which has crosschecked the claim ?

Let me say that I have a 100 years data, then

*means whether it is the first 10 years or first 15 years or first 20 years? How to come to a conclusion ?***start of the time series**I attended a training to learn Hydrological Modelling Using SWAT, which is a widely used model, back in 2018.

We discussed about the details regarding calibration and validation of a model and were told that 7:3 is like a golden ratio for calibration and validation. Basically, if you have 10 years of observed data, you calibrate the model for 7 years and validate the same for 3 years. As a beginner in hydrological modelling back then, I engrained this piece of information in my brain.

But as I keep reading through various research materials, I have realised that there is no obvious pattern or thumb rule for this. I recently read a paper which calibrated a model for 1 year worth of observed data while validating the same for 5 years.

So I'd like to know your approach when you work with a hydrological model and the factors which influence your decisions on how much to calibrate or validate.

- In non-parametric statistics, the
**Theil–Sen estimator**is a method for robustly fitting a line to sample points in the plane (simple linear regression) by choosing the median of the slopes of all lines through pairs of points.*Many journals have applied Sen slope to find the magnitude and direction of the trend* - It has also been called
**Sen's slope estimator**,**slope selection**, the**single median method**, the**Kendall robust line-fit method**,[6] and the**Kendall–Theil robust line**. - The major advantage of Thiel-Sen slope is that the estimator can be computed efficiently, and is insensitive to outliers. It can be significantly more accurate than non-robust simple linear regression (least squares) for skewed and heteroskedastic data, and competes well against least squares even for normally distributed data in terms of statistical power.

*My question is are there any disadvantages/shortcomings of Sen's Slope? Are there any assumptions on the time series before applying it.? Is there any improved version of this method? Since the method was discovered in 1968, does there exist any literature where the power of the Sen slope is compared with other non-parametric? What inference can be made by applying Sen slope to a hydrologic time series explicitly? What about the performance of the Sen slope when applied on an autocorrelated time series like rainfall and temperature?*I have 18 rainfall time series. On calculating the variance, it was found there was an appreciable change in the value of variance from one rainfall station to other. Parametric statistical tests are sensitive to Variance, does it mean we need to apply robust statistical tests instead of the parametric test?

After running a simulation in HEC-HMS, I'm getting the following warning:

Warning 42403: Time of concentration increased by one time interval (24h) in basin X.

This is causing my simulated hydrograph peak to occur 24 hours after the observed peak.

What can I do to resolve this issue?

Thank you.

I read a thesis which used the formula v = K(S^0.5) to determine the flow velocity in a channel. The value for conveyance K was adopted from Ward and Trimble (2004) and was mentioned to be equal to 5 for a river bed composed mainly of sand and gravel. Can anybody help me find the K value for a river bed which mostly consists of boulders with patches of vegetation?

Thank you.

I have used the following parameters to simulate:

1. Loss method: SCS-CN, 2. Transform method: Clark UH, 3. Routing: Lag.

My simulated peak occurs 1 day after the observed peak.

It shows "Warning: Time of concentration increased to one time interval at subbasin X" which I'm assuming is the reason for the discrepancy.

What parameters can I adjust to shift the peak by 1 days and to esolve this error?

Thank you.

I want to set up a minimum amount of outflow (1500 cumecs) through a junction or reach or basin so that if the inflow there is less than the value above, it results in zero outflow. Is it possible?

I am trying to use HEC-HMS for streamflow modelling of a river. The thing is that I have only one gauge in my study area located at the outlet of the catchment. I've been through some materials which mention that inflow data is a basic requirement. However, the gauge flow data at the data at the outlet has to be considered as outflow data if I'm not wrong. Is there any other way to go about this?

I want to check the Homogeneity of a rainfall time series. So i applied the following four methods and found the time series to be non-Homogeneous

- Von Neumann ratioTest
- Buishand range test
- SNHT
- Pettitt's test

Is there any R package available in CRAN which make non-homogenous series back to homogenous ?

Although I check that the flow accumulation tick is OK in display options, but still there are no streams on the map...

How to fix this in order to continue watershed delineation?

best regards

Have a nice day everyone, I've created a watershed model via WEAP software for modeling water budget of a basin. Now, I'm planning to construct another model using another software/program for modeling the same area and compare different models' performances.

Lastly, I'd like to ask you about "Pysheds" model's weaknesses and strenghts, plus I'd be so glad if you could share with me tutorials through which I can figure out basics of "Pysheds"

Thanks in advance

Grubbs's test and Dixon's test are widely applied in the field of Hydrology to detect outliers, but the drawback of these statistical tests is that it needs the dataset to be approximately normally distributed? I have rainfall data for 113 years and the dataset is non-normally distributed. What are the statistical tests for finding outliers in non-normally distributed datasets & what values should we replace in the place of Outliers?

I have Monthly rainfall data from 1901-2013 for 29 stations covering the entire state of Kerala. I took the first 80% of the data for training the model and the rest 20% for validating it. I developed SARIMA monthly model for forecasting rainfall. The reviewer has asked

**What is the scientific basis for forecasting rainfall over a point location (station) over a longer time scale (a Month)?**What was the reviewer trying to convey by this question?Dear colleagues,

Actually, I am looking such discharge data for any stations in Sobat river basin and the White Nile basin, as well.

I will be thankful if someone can share it with me.

Regards,

I have to implement Green Ampt Infiltration equation for daily time step with regional scale over different Land use/Land cover conditions. The Green Ampt parameters are estimated using soil properties, how the equation could be improved for different LULC conditions and what could be the effect of varying spatial and temporal resolution in model performance.

Hi friends! I ran my project successfully, however there are some reservoirs in my basin. Hence, I have to rewrite data again and set the reservoir parameter up.

Unfortunately, I don't work and the text box show that my reservoir area and volume have to be less than a number (I showed in the picture below). Meanwhile, my real reservoirs are larger than that number.

Does anyone get the same problem with me?

Your answer will be a big help for me. So many thank!

Hi

I'm using three different performance criteria for evaluating my model:

1.Nash–Sutcliffe (NSE)

2.Percent bias (PBIAS)

3.Root mean square error (RMSE)

You can suppose that I used a regression model to estimate a time series data such as river mean daily discharge or something like that.

But for a single model and a single dataset, we saw difference performances for each criteria.

Is this possible? I expected that all of these three criteria have same results.

You can see the variation's diagram of these criteria in appendix pic.

Thanks

I wanted to ask that if we have to develop a modelling tool to anticipate the impacts of weather extreme events on the water quality of a lake but the amount of information collected in the field is scarce. What kind of models would be better to use and which are the natural processes we should include in the models. Please guide me briefly if possible.

Is anybody familiar with AquiferWin32 ver 4.0?

I need a jump start on how to run this program, specifically how to add background in the model, add well and then run. Thanks.

I am using SWAT to simulate stream flow in a river. All the steps are performed well, but the error appears when I come up to the last one "Run SWAT". The error is released by cmd.exe as the attached photo. I do not know what kind of error is it and how I can correct it as well. Please give me any recommendations to solve this problem. Thank you very much.

Hi,

Except synoptic stations, does anybody know any website/software that gives the climatological data of unequipped places?

I am aware of using interpolation methods, but, I am looking for a method that extract data for a desired location numerically (like an excel format etc,.).

Thanks,

The parallel drainages are commonly observed over estuarine environments, flood plains and reservoirs of the area

Hello all,

i am new to water chemistry, i have been looking at trends in the water chemistry parameters, and found there is significant decreasing trend in Stream-water temperature, Ca, Mg, Na, and chloride along with discharge both in the monsoon and non-monsoon seasons.

Like From Jan 1994, Jan 1995, Jan 1996...... Jan 2018 (for Non-Monsoon period) Sept 1994, sept 1995, sept 1996...................Sept 2018 (Monsoon period)

Note- watershed (1000 km2 drainage area, Western Ghats, India) is free from dams and other water structures.

What could be possible drivers of trends in the above parameters?

Please provide your valuable suggestions.

Thanks in advance.

Regards

Rajat

I am unable to find literature having acceptable rainfall performance criteria as is available for other parameters such as wind, temperature, etc. Is it correct to define a criteria based on the 90th or 95th or similar percentiles from the population of rmse, mean error values?

Dear Researchers,

I run multiple times my SWAT-CUP SUFI2 but it is contineously giving this problem as attached in picture. Please let me know your expert opinion why I am facing this error and how to fix it.

Thanks in Anticipation.

Kind Regards

Naveed

I want to run 5 different models to estimate stream flow. In order to optimize the characteristics of these models I use Taguchi method. So I have to run different models according to the Taguchi orthogonal array. Therefore, I have different models with different inputs and different data lengths. For example the first test is: using rainfall and temperature in ANFIS model with 2 year data length, while the second test is: using rainfall, temperature and discharge for previous day in SVR model with 10 year data length. So, the inputs, Data length and model type is changing in these tests. What is the best performance evaluation criterion for this study? NRMSE can be a good criterion because it normalizes the RMSE and in this way, it removes the effect of data range.

Now, I want to know if there is any better solution for this problem.

I have a daily flow data at the outlet of my basin. From that data, how can i estimate base flow parameters?I am currently using constant monthly method and i am using a trial and error approach..but i want to explore other possibilities of baseflow methods such as recession baseflow for which i would beed recession constant, initial discharge and ratio to peak.. How can i estimate these parameters?

I see huge discrepancy between researchers (difference for the same class is somewhere up to 0.2). What determines the choice of the appropriate value ? What is the role of spatial resolution of the research in this ? Thank you.

Of course there is "urban" table, but it isn't enough since I try to model large city. Especially I have problem with green areas such parks, lawns, orchards and courts. BTW, in the table there is a field "urb cn" with value always 98 - does it force CN number in HRU?

If so, is it a good idea to split landuses on urban+grass, depending on %of impervious surface?

I've chosen swat+ because of its popularity, but maybe there is a better software for hydrological modelling of urban areas?

I am very new in hydrodynamic modeling. Recently, I have done a simulation in SMS-SRH 2D. Now, I want to perform calibration and validation of my model. But, I have no basic on calibration and validation. Can anyone give me some documents or tutorial or guidelines on calibration and validation of numerical model which will, not only build my basic but also make me able to perform on my existing simulation?

Some specific questions:

1) What are the parameters need to be used for fine tuning of model during calibration?

2) If I have limited observed data, will model give satisfactory result?

3) During validation, shall I use different cross section of another time period for my model domain?

I am looking for a hydrological model and a crop model that i can couple to predict crop yield and also to develop an improved irrigation scheduling for dry season vegetable production in a river basin in Ghana for a PhD research work. Please I need suggestions on hydrological and crop models that are available for free on the net. Thank you

I am required to do a project where I have to calculate discharge of streams/ watersheds in a high altitude area with extremely treacherous terrain. Will it be possible to achieve this objective using GIS and remote sensing, without field observations ?

Is there any particular rule that told us in what condition we allowed to rebuilding missing data in a synoptic station?
For example, if a station has 15% missing data over 30 years, can it be filling? In other words, is there a specific rule that says up to what percent of missed data we can reconstruct it and used in drought studies?
Can this data be filled in by taking a regression from the station itself, or should it be filled in by nearby stations?
The time steps are in monthly.
Do you have any referenced article for that?

Thank you in advanced
Best Regards

I am new to hydrogeology but I want to understand what is required to be measured at the field or site which will form basis for MODFLOW FLEX 3D modeling.. I want to to know the specifics to be gotten at the site. The rivers, lake, recharge... where do I require resistivity, every form of measurements needed to be calculated, please I’d like to know and where I can get the information I need as well... thanks

I have known some physical-based models and emperical models, i.e., the original Stefan model (mainly used in permafrost regions) and its modified modes. However, I consider there would be some better methods to quantify the dynamics of frost depth in seasonal frozen soil region.

Due to the characteristics of two-way melting of the soil during the thawing period in seasonal frozen soil regions, the prediction of the frost depth during the thawing period becomes more complicated and difficult. Are there any good methods to quantify the dynamics of frost depth during thawing period?

Currently, the combined effect of all clouds is one of net cooling, meaning that clouds are dampening the rate of climate warming. But scientists are looking into whether clouds will have the same effect on climate as the Earth continues to warm.

**If the proportion of different cloud types changes, it could affect the rate of climate change because different types of clouds have different impacts on the Earth's climate. While some types of clouds help to warm the Earth, others help to cool it?**Hi, i noticed on youtube that a lot of researchers change the unit of the degree slope map to radians on raster calculator while the original formula stays in degrees. because if we work by degrees, the result will be negative values, on the other hand in radians, there will be positive values.

Best regards

We know that there are lots of tools to manage the floods. Those tools may be software tools or procedures. But have we clearly identified all the components and stakeholders in the tools?.

Then I have developed a conceptual model which consists of not only stakeholders but also the hydrology model and GIS model.

I need to confirm the model or need your observation to modify it.

Hence express your ideas on

1. Do you agree with the components identified?

2. What are the additional components to be included in the model?

Thank you

I have eight rainfall events with length of 476 days. i want to predict the peak discharge and peak time.

I am trying to calculate the LST of three land types existing in permafrost regions of NWT, I am using Landsat-8.

Is the thermal imagery of Landsat-8 a good source for deriving LST of a local scale?

And,

I was wondering,

which time of year is the best time for this process?

we are considering to develope the SUSTAIN model adding some new functions. the officia website on USEPA applied the source code of its interface and simulation engine, but it's an extension tool based on arcgis 9.3.1, we have no idea to use the dll files, got from source code, with arcgis platform.

asking for help sincerely, by a rookie.

moreover, is there any possibility to transplant this model to newer version of arcgis 10.x, that could be a "big" project which USEPA was not willing to do.

Hello all,

I am looking for Acoustic Doupler Current Profiler (ADCP) which are found to be performing well for streamflow measurement. please share experiences and suggestions for selection of appropriate ADCP for streamflow measurement.

Thanks.

Regards

Rajat

Dear Researchers,

I have created the soil user file and now working of LULC file. I have done almost all only remaining are following:

Townland and

Ruralland

Both belongs to urban landcover, so its code must come from Urban database and accordingly code ID will be assigned in the user define Land-use text file. AM I right?

Secondly, Desert, Dryland and Plaindryland I am still struggling how to replace them from the land cover closest category.

Could you please guide me how to fix these problems.

Thanks in anticipation.

Due to environmental impacts of dams such as:

- problems for the surrounding area, for plant life,

- dams block up flowing bodies of water, such as rivers, any animals that depend on the flow to reproduce or as part of their life cycle are put in danger.

- Harm water quality and temperature.

- Block fish migration

- ...

What I want to know is that table value only for United State or It can be used over the any place of world?

I have a Annual Rainfall time series data (1987-2017). I am determining the trend in the data using MK test. However I found that if there is a serial correlation we should go for MMK test.

Therefore I calculated correlation coefficient at different lags for the original data (upto10 lags) and found that the correlation coefficient are within the tolerance band (within upper limit and lower limit at 5 % significance level) except at lag 4 it is above Upper limit.

Does this mean the series is autocorrelated?

What is the criteria for going for MMK test?

Do we really need to perform student t test corresponding to lag 1 correlation coefficient? Is this test justifiable?

This makes me confused because at lag 1 there is no auto correlation (it is within tolerance band) however at lag 4 there is auto correlation.

So there is mismatch. Student t test would entail no autocorrelation whereas the correlation coefficient at lag 4 entails there is auto correlation.

Your help would be appreciated

Does anyone know how to calibrate a PR2/6 SOIL MOISTURE PROBE in the field?

Hello Everyone!!

i'm working on Hydraulics particularly on Scouring,

i have Scour depth data and Parameters affecting to scour. now i would like to carryout sensitivity analysis on the parameters to predict the scour.

Currently i don't have the scour model, based on data i would like to carry out Sensitivity analysis ,

please suggest some suitable method for the sensitivity analysis.

Thank you.

Hi,

I would like to estimate very roughly the time necessary for a river to travel a long par of it's course (approximately 50km).

Sadly the course has not been studied, neither modeled, we don't know the shape and section of the river on a distance that long. Anyway we have several measurements of the river flow (middle of the river, 1 meter deep) along the river course.

We would like to reach the magnitude of residence time of water, in order to compare it with pesticides half-life in water.

Thank you for sharing your knowledge,

I am looking for data set to develop a flood forecasting system specifically for an agriculture dominated watershed. The requirements include a) fine resolution DEM b) land use type and soil hydrologic group c) hourly/sub-hourly rainfall data for a minimum of 30 years d) hourly/sub-hourly stream flow data and e)demographic details of the area. It would be helpful if you suggest any data repository/experimental watershed for collecting the above mentioned data. I assure you that the services offered will be duly acknowledged.

We observed a huge difference between simulated and observed outflows from a catchment during a hydrological modelling exercise in HEC-HMS. The catchment contains numerous ponds and smaller lakes (of varying areal extent), lacking operational data. How can we account for the effect of these storage structures in the hydrological modelling?

I'm looking for methods to separate

**different sources contributions**to suspended sediment concentration / sediment yield :Either to quantify the volume or to obtain partial concentrations of the hillslope portion or the in-chanel portion based on Time-Discharge-Concentration data series.

Most methods I find use fingerprinting, I don't have the data required for such methods. Thank you !

I have four values of discharge such as discharge value of 1, 15, 18 and 25 august. I want to construct a unit hydrograph from these values. How can I perform this?

**What is the main challenges in water sector based on main events? (like drought, flood, agriculture, industry, etc)**

**I'm looking for a framework or divide of challenges in this manner.**

**like we can say in agriculture main challenge could be the low efficiency of irrgation.**

I have downloaded the data but observed that each year is given in separate files. I need to extract each year separately that is time-consuming. Does anybody know any easier way to extract data together in time series from 1961-2007 for a particular location?

Thanks,

**Dear Researchers,**I have daily flows data 1961-2015 and some of the months flows data is missing. This missing period varied; 1 mont, 1.5 months, 7 months, randomly. I would like to ask how to generate this missing data? Please share your expertise and skills. Thanks in anticipation

**Regards**

**Naveed.**

I'm dealing with a time series of stage data (water surface level) measured with a pressure transducer submerged in a river. In a an early analysis, I've found noise in the data and moved on to apply a filter (like Savitski Goulai) to smooth data since it will be used as input to a hydrological model. In a futher analysis, I've found that the noise was actually oscillations with a semi-diurnal period, i.e. approximately 12 hours, with peaks at 10:00 am and 10:00 pm, which corresponds to the peaks of barometric pressure (known as barometric tide) measured in a nearby station. Therefore, I suspect there was something wrong with the barometric compensation of the measurements. Probably I'm working with an absolute transducer, not a vented one (not sure about the source). Some compensation had to be made since stage data is not very high (as you can see in the Excel file provided).

My questions are 2:

1. Are the oscillations really the result from barometric changes in pressure and incorrect compensation from the transducer?

2. More important: is there any way, knowing the "real" closeby atmospheric pressure, to compensate and eliminate these oscillations?

Thank you in advance!

For a linked simulation-optimization modeling, how can I run the GMS (Groundwater Modeling System) software using C ++ programming commands?

Has anyone a complete data of a coastal aquifer to simulate saltwater intrusion using GMS software?

Dear Researchers,

I would like to ask that between

**Wa**ter Flow and Balance**Si**mulation**M**odel (WaSiM) and Cold Regions Hydrological Model (CRHM) which is good model in permafrost hydrology prespectve. I have to choose anyone between these two models. I am confused and not yet finally decided.Expert opinion is highly appriciated and valuable.

Thanks in anticipation.

Regards

Naveed.

With application of kalman filter , How can we inclusing of model error Q ?

probability of transition ,modeling, Markov chains

Hi,

Please let me know is this the right approach for the calibration of flow in SUFI2?

1. I should first check the performance of initial model with observed data :

i. Should I compare the simulated results given as "flow_out" in the "rch" file in SWATOUTPUT.mdb with the observed data?

ii. Should this be performed for the whole discharge period or only the period for which I intend to perform calibration?

iii. Should I compute the waterbalance before doing calibration using my first model and pleae let me know what else i should check apart from comparing the observed and simulated discharge in the first step.

2. Based upon the comparsion of simulated and observed flow I should do the regionalisation of parameters.

2. Sensitivity Analysis to find out the parameters most sentive for the watershed with regards to flow.

3. I should set the range for the parameters identified in step 3.

Can i first use the ranges provided as default in SWAT-CUP or I should set the ranges based on literature review (in case I find any). For this step I should run the simulations from 500-1000 times and check the values of Objective funcion and 95PPU and r-factor. If the ranges are satisfactory then those ranges set for the parametsr will be final otherwise i should repeat the model for another 500-1000 simulations by changing the ranges.

please correct me if my approach is wrong.