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# Rainfall Runoff Modelling - Science topic

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I mean after calculation of Mann Kendall test
Of the many possible options for such problems related to shift and change detection, another potential choice is a Bayesian changepoint method available in R, Matlab, and Python (https://github.com/zhaokg/Rbeast). It has been used for problems in dozens of fields. Maybe it helps with problems like yours, but it may be not.
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(Matlab, R, Python, ...??)
taking into account the current evolution of artificial intelligence
you don't regret with Python
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Can somebody provide a paper which states that the model validation efficiency tends to be lower than model calibration efficiency?
When dealing with modeling processes, everything can happen since you cannot predict the performance of a model before you test it on a data set. But you can confidently say that since the models are trained to fit the calibration data it is natural that the calibration efficiency (precision) is higher than validation.
Furthermore, I don't think you would find such a paper. I mean, to be honest, the subject it is not important to try to find a way to analytically prove whether the validation precision of a modeling process will tend to be lower. What will be the gain of such a result? Take also into account that it is not even certain that such proof even exists.
Moreover, to make a robust statistical claim we need to analyze a very huge set of models with a very much more enormous set of data. It is virtually impossible to study every model using every kind of data for every purpose possible.
I think if you stated more precisely, what you exactly you are after you definitely can find your answer here.
Cheers!
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Dear all,
I am going to derive the precipitation data from NETCDF files of CMIP5 GCMs in order to  forecast precipitation after doing Bias Correction with Quantile Mapping as a downscaling method. In the literature that some of the bests are attached, the nearest neighborhood and Inverse Distance Method are highly recommended.
The nearest neighbour give the average value of the grid to each point located in the grid as a simple method. According to the attached paper (drought-assessment-based-on-m...) the author claimed that the NN method is better than other methods such as IDM because:
"The major reason is that we intended to preserve the
original climate signal of the GCMs even though the large grid spacing.
Involving more GCM grid cell data on the interpolation procedure
(as in Inverse Distance Weighting–IDW) may result to significant
information dilution, or signal cancellation between two or more grid
cell data from GCM outputs."
But in my opinion maybe the IDM is a better choice because I think as the estimates of subgrid-scale values are generally not provided and the other attached paper (1-s2.0-S00221...) is a good instance for its efficiency.
I would appreciate if someone can answer this question with an evidence. Which interpolation method do you recommend for interpolation of GCM cmip5 outputs?
Thank you in advance.
Yours,
Can you please refer to the tools and codes used in regridding?
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My study area is extremely large (multiple valleys) and precipitation is close to zero. Streams are often dry, but runoff almost solely comes from glacier melt and is heterogenous throughout the valleys. I have extracted stream boundaries for hundreds of basins using a machine learning algorithm and I can get channel geometry such as width/depth/cross sectional area (at any point along the stream), wetted perimeter etc. Is there any way I can get approximate velocity, discharge, etc at bankfull using stream geometry and a corresponding DEM? Maybe using slope and geometry?
The Manning's n approach has been around for quite a while and may suit your needs quite well. Having said that, simply bear in mind that the approach assumes that all flow is 1-dimensional. In other words, this numeric model assumes that the water in the channel essentially flows in a straight line. Perhaps you are familiar with the old phase 'all models are wrong, some are useful'. Point being, just remember that the output you get is an approximation. In the off chance you have some measured discharge values in your study area, this can help quite a bit to calibrate the roughness values you end up using.
The HEC-RAS 1-D model relies on the Manning's equation for its calculations. If you crank up the roughness values, this will result in slower velocities and higher water surface elevations. Conversely, if you lower the roughness values, this results in higher velocities and lower depths.
As for the value of Manning's n that you use, I'll admit that these references might not be the most appropriate or useful for you particular application. Having said that, it doesn't mean that you can't learn something from these references either. So yes, they are 'oldies' but they are also 'goodies' and they can help to you start to better understand some appropriate Manning's n values.
Limerinos, 1970. Determinination of the Manning Coefficient From Measured Bed Roughness in Natural Channels
Arcement & Schnieder, 1989. Guide for Selecting Manning's Roughness Coefficients for Natural Channels and Flood Plains
Verified Roughness Characteristics of Natural Channels
Hopefully these references prove helpful. Best of luck with your project.
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any one know about how to prepare intensity duration frequency curve for estimation of peak flow for rainfall runoff modeling for ungauged watershed
Hi,
It's possible too use analysis by cross-correlation between rainfall and hydrograph. You obtain the lag between rainfall and flood.
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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.
Interesting question. In addition to the very useful comments and replies from colleagues, I would like to add some observations and comments. The calibration and validation strategy depends on different factors, such as the purpose of the modelling and possible final application, the availability of data and the hydroclimatological conditions in the studied catchment(s).
The modelling purpose can be very general (e.g. simulation of hydrological regime and behaviour of a catchment), specific (e.g. low flows) or supporting water systems and infrastructure design (extreme, non-observed conditions) and future impacts (e.g. due to climate change). Calibration and validation strategies for general purposes can be more straightforward by using the split-sample test and dividing the time series in two parts, indeed generally somewhat more data for calibration (e.g. 2/3) than for validation. Specific purposes and support for design and impact assessment require more tailor-made approaches showing the robustness of the model. For instance, for flood design purposes one would like to show that the calibrated model can also be used for more extreme conditions than the calibration conditions. Hence, one might select the calibration and validation periods in such a way that the validation period includes more extreme events than the calibration period. In this and similar cases a so-called differential split-sample test is therefore more appropriate. Similar reasoning applies for climate change impacts studies, where you might want to show that your model can also be used for changed climatic conditions. This can be (partly) achieved by selecting a validation period with (hydro)climatological conditions more similar to the expected changed climatic conditions than the calibration period.
Data avaliability obviously determines what is possible in the calibration and validation. When for instance streamflow data are not sufficiently available, you might look for alternative data regarding other output variables such as actual evaporation (e.g. based on satellite information) or state variables (e.g. soil moisture, snow and groundwater). Different calibration strategies for multiple variables (and objectives) are available in the literature, see for instance .
Recommended splits for calibration and validation periods (e.g. 50-50 or 70-30) will also depend on the hydroclimatological conditions in the study catchment (e.g. the occurrence of dry and wet periods) and the hydrological model used. The systematic study mentioned by Mehmet Cüneyd Demirel provides a nice example of the detemination of the optimal data length, but results obviously depend on the hydroclimatological conditions, the catchment characteristics and the model used.
Good luck,
Martijn
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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.
Harsch, you need to give some more detail about your model setup in order for anybody to be able to say anything about what may be the cause of this.
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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.
Thank you everyone for replying. I had an inkling that the equation referred to the Manning's equation. That is why the thesis author using a K value of 5 by jyst looking at the channel bed surface made no sense to me. To be honest, tgat thesis smells fishy to me now.
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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.
Brahim Abdelkebir I've found that if the input time of concentration is less than your simulation time step, then it is automatically increased to match the simulation time step (24h in our cases). So you'll have to reduce the simulation time step. The output graphs will look weird but this is the only solution I could come up with.
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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?
Define a reservoir, then put a pump on that and play with the rule base of the pump such that it always pumps unless (some condition you like)
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Can somebody please provide links to papers consisting of tables with maximum canopy storage values against corresponding landuses? Classification of landuse as used by ESRI is preferrable.
Hope you get some idea from the following paper
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After running a simulationa and comparing the simulated discharge with Observed discharge the values of Nash Sutcliffe coefficient has been -40.473, and after optimizing the value comes out to be -8.216. Which steps can i take to have NSE to 0.65-0.80.
Which factors can i optimize.
If your discharges are affected by a reservoir operation you should make them natural flow by using reservoir operation records.
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I am doing uncertainty in rainfall runoff model ("hbv") and wants to get optimal value of parameter, but the difficulty is the selection of the likelihood function? (the cod in Rstudio and interpretation)
I would start with the normal likelihood function. See the attached to get started. Best wishes David Booth
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Hello Everyone,
I am a hydrologist and want to model baseflow (i.e. surface-water groundwater interactions) via the development of a numerical groundwater model (GW model). One of the critical input parameters for the development of the GW model is the hydrogeology of the catchment in question.
Bore-well lithology datasets required for preparation of hydrogeology map or Fence Diagram is very limited (2 borewell logs only), Since, my study area lies in the headwater mountainous region. I am planning to do an electrical resistivity survey for mapping the hydro-geology of the basin in the catchment area of 102 Km2. I have a few questions, in planning Electrical survey in the basin-
1. What could be the optimum number of resistivity profiles required for appropriate representation of hydrogeology of the basin?
2. How to identify the most appropriate locations for Electrical resistivity profiling representative of the basin under consideration?
I request you all to give suggestions in this respect.
Thanking You.
Regards
Rajat
In general, for this area of land, you must first try to drill at least 10 boreholes. This is so that you can have parametric soundings to calibrate and validate electrical soundings.
Now, and given that the number of drilling is very limited, it seems judicious to me to carry out a grid of 500 m and to carry out a sounding (SEV) with AB/2 of 1000 m in each point of the grid.
The solicited depth of the SEV depends on the increase in the depth of the aquifers (according to geological data). It is therefore necessary to increase the length of electrical soundings in the areas of increase in P and to add SEVs with AB/2 between 3000 and 5000 m (for example).
The establishment of the geo-electrical profiles can be distributed, according to the configuration of the ground, in the following way:
Total number of SEV Number of profile Number of SEV/profile
Zone 1 24 04 06
Zone 2 18 03 06
Zone 3 20 05 04
Best regards
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Hello everyone,
During calibration of a hydrological model using synthetic data, I was trying to add Gaussian noise to the simulated streamflow data. But many streamflow values are near to and equal to zero, if I add a Gaussian noise with certain standard deviation (lets' say 10%), it will make many data values negative. But streamflow data values as negative will be invalid.
Could anyone please suggest how should I proceed ? Also, cite studies which supports that method.
Oh I see, thanks for explaining!
It seems to me that you already provided one possible answer to your question: Your model should include noisiness of data.
Are you somehow stuck with a model that cannot adequately handle noisy data?
If so then you will have to fudge a bit and check if your fudgy approach will cause unwanted error/bias in your calibration. E.g.: Do you expect problems if you simply add the noise you had in mind and turn the negative values to 0's before starting the calibration?
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1. Which is the correct order in Data-processing of rainfall time series- Homogeneity test followed outlier detection & treatment (OR) Outlier detection & treatment followed by Homogeneity test?
2. I have monthly rainfall data for 113 years. I am planning to run four homogeneity test- Buishand range test (BRT), Standard normal homogeneity test(SNHT), Von-Neumann Ratio (VNR) and Pettitt.
3. Which is the appropriate method for identifying outliers in a non-normal distribution ?
4. Should the descriptive statistics(DS) and Exploratory data analysis (EDA) should be conducted before (or) after treating the outlier? (or) a comparison should be made in the EDA & DS before and after treating the outlier
You should first check the discordancy in R that will tell you if any of the regions in your dataset are discordant (means gross error or outlier) then further do a homogeneity test.
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Hello all,
I have been trying to find out length of longest flow path, through GIS but it is always giving me the vlaue of 0.29 whereas my study area is 6896 km2. How to solve this problem.
Hello again Mr. Nazar. I recommend you to use HMS to calculate longest flow path. I used GRASS GIS R.LFP toolset in the past but with version of HEC-HMS 4.6 the computation is much simplier here. But it require to set up digital elevation model in HMS.
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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"
IntErO model for calculation of soil erosion intensity and runoff
Dear colleague/s,
(to Ibrahim, but open to some other interested colleagues)
I am kindly inviting you to have a look at the application of my IntErO model for the calculation of soil erosion intensity and runoff (link):
IntErO model
- Simple installation;
- Examples of applications available on the same web page (but also on RG and on www.geasci.org/Publications);
- I, as an author, am available to demonstrate how it is working.
Finally, in case you decide to compare the results received with using the IntErO with some other model/s and or measurements, I will try to arrange to finance the publication of the paper having in a team of authors two of us from my team,
Sincerely,
Velibor Spalevic
Mob/Viber/WhatsApp: +38267201222
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I am looking for modelling tools that are capable of simulating the impacts of green infrastructure.
Check on this paper.
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Hi all,
I was thinking about applying the downscaling statistical methods on GPM using the MODIS cloud level 2 . However, I am not sure about it from the prospective of its validity on arid or semi arid areas with low number of observations for instance.
This is a good question.
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Hi everyone
I am trying to run the CESM model, in order to evaluate teleconnection in a rising temperature levels, in low-mid atmosphere conditions and the rainfall patterns in the Andes of South America.
But, I am newbie in this, so I am having some troubles indeed, when I execute the ./create_newcase this command does not create a new folder into my directory, I was finding out what I did wrong but I am lost
Can anyone  help with this one?
Thanks a lot!
That is a good question.
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HI everybody
I am trying to run the CESM-atm model, but I don't get where is the path for the data, I am attaching an image of what must be the structure of the path.
By the way, I am running this model in my personal lap, so I had to do the porting proccess before, so I don't  think that would be really the problem here.
Could anyone explain me what I must do for downloading the data for the model?
Thanks a lot!
That is a good question.
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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.
That is a good question.
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i wish to know how to decide whether we need to use MIKE Basin for a particular catchment or do we need to use MIKE Rainfall Runoff model NAM.
That is a good question.
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I want to work with HEC-HMS on rainfall-runoff simulation & when I wanted to build the catchment polygon layer, I faced the error that says:
"the system cannot find the file specified"
I searched a lot but I didn't find the way for my problem.
NOTE: The catchment grid layer has been built successfully, but when I checked it's file in the saving path, it had only 8 items, but the other layers had 9 items in their files.
It didn't have the log file, but the other layers had the log file. My system RAM isn't full.
What do you suggest for my problem?
Which version of the HEC-HMS do you use? Naqash Taroob
In the newer versions you can import GeoTIFF files, maybe this way helps you
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Dear Researchers,
We are aware that a shift in monsoon peak discharge may have an adverse impact on several water-based applications such as agriculture, dam operations, etc. E.g. I am interested to know how to quantify the same based on modeling approaches. Thank you!
Sincerely,
Aman Srivastava
I think these papers could help you;
1. On the Suitability of GCM Runoff Fields for River Discharge Modeling: A Case Study Using Model Output from HadGEM2 and ECHAM5, February 2012,
2. Development of a high resolution runoff routing model, calibration and application to assess runoff from the LMD GCM, September 2003,
3. Climate change and its impacts on river discharge in two climate regions in China, November 2015,
4. Modelling the potential impacts of climate change on hydrology and water resources in the Indrawati River Basin, Nepal, February 2016,
They're available on the ResearchGate Server for download.
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I'm having a hard time using TopoIndex (which is the first step). It keeps on getting an error which says that the corrections did not converge (regardless of how many iterations). Any troubleshooting tips?
Hi!
Has it ever happened to you that TRIGRS gives the maps all the same even changing the input values ​​in the model? Gridmatch doesn't show any errors and TRIGRS runs without a problem but then my Safety Factor maps are all the same regardless of whether I change values of precipitation, time, etc. Can anyone help me with this problem?
Thanks!
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Is there any way to calibrate a rainfall-runoff model with Hec-Hms anything other than discharge? The thing is I don’t have continuous discharge data availability. But I have water level and cross-section data. Is there any way to calibrate through water level? It's important for the thesis project I'm working on.
Hi, Najmus!
I suppose you have water level and cross - section data because you have a canal or, more likely, a river reach. And I suppose you have a maximum level into that stream. So you are trying to calibrate for the peaks of a storm.
If you are going to use the SCS method, you will only need to vary the Curve Number to get the maximum flow. So you will get the CN of your basin, but acccording to the SCS transformation.
If you have the CN (because in your country that value has been set by an official ocument) the CN is given; so you will have to use the Clark transformation method, and you will just be able to calibrate the storage coefficient.
If the basin is big and complicated, you will also have transport reachs, and you will have to estimate transport parameters. I advise you to use Muskingum - Cunge routing.
I also hope this helps a little bit!
José Luis
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For my future discharge forecast in the calibrated HEC HMS model, i need the precipitation data of the future.How can i get this data in the daily timescale?
Interested
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Because I see that to estimate soil loss throught USLE, RUSLE models, some researchers use models that are not compatible with the study region?
If referring directly or indirectly to the USLE R factor, sometimes called the rainfall runoff factor, it is developed from the frequency and intensity of rainfall events, on average, for specific areas. The US has a map developed for this. The rainfall intensity is one of the driving energy factors or forces that is accumulated into an energy R factor from long term rainfall records. Rainfall rates exceeding 3 inches per hour are apparently the maximum rainfall intensity applied as either the amount sufficient to dislodge soil particles, or perhaps that rate on agricultural soils often leads to puddling, which absorbs any added energy from more intense events. Soil loss estimates through USLE and associated equations do not include any erosion associated with channelized flow, it is basically what one might call sheet erosion and sheet flow. The USLE estimates the dislodgement, entrainment of soil particles in this surface flow and movement and deposited to another area or delivered to a channel network. Since rainfall is the driving force for particle dislodgement, it seems that soil loss models would have to consider local or regional rainfall information. Wind blown soil is another force consideration that is not evaluated in rainfall or runoff with USLE soil loss estimate.
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My study area of rainfall-runoff modelling is in mountainous region and has snow cover. There is about 10 percent snowmelt contribution to the discharge of the river i am modelling. How can I include snowmelt parameters to enhance my study? any tutorials on snowmelt modleing in hec hms would be welcome..Thanks in advance
Have a look at this related work :
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I am doing my project work in snowmelt runoff modelling. I have collected a Matlab code which I found very difficult to understand due to its complexity.
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Hi all, i'm trying to implement the SM2RAIN algorithm in python for estimating precipitation in USA based on soil moisture observations, i started by gathering data on county level.
I used " NASA_USDA/HSL/soil_moisture" for the SM observations, basically the SURFACE SOIL MOISTURE (ranges from 0 to 25mm), the temporal resolution is 3 days (the lowest available one)
For the precipitation, i used "IDAHO_EPSCOR/GRIDMET" for daily observation, i resamplead the data to 3 day accumulated values.
I implement the algorithm using this code freely available on github " https://github.com/IRPIhydrology/sm2rain/blob/master/sm2rain/algorithm.py ".
I normalized the surface soil moisture values and got started with on county (320 observation)
I used the pearson's correlation R and RMSE as metrics for evaluating the output of the model.
The calibration process was processed on the whole dataset
PROBLEM:
The issue is that i'm getting a low R value (below 50%), and the simulated precipitation always has the same pattern as the soil moisture.
the simulated precipitation cannot catch the hight values of observed precipitation as you see in the attached file (orange color: observed precipitation/ blue color simulated precipitation [only 30 points in the graph]
Questions:
Did i choose the correct soil moisture variable ?
it is normal that simulated precipitation has the same pattern as the soil moisture ?
Any tips or suggestions are appreciated.
Very late answer :)
I believe there's a temporal mismatch between soil moisture and precip data.
Two suggestions:
1) you can send us the SM and P data to have a quick check
2) please note that an updated version of SM2RAIN algorithm is available in GITHUB: https://github.com/IRPIhydrology/sm2rain
I am at disposal for any question
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I have downloaded the MSWEP sub-daily rainfall data (3-hourly data 0.1 degree resolution). I used MATLAB to convert it and obtained a table of dimensions 1800 x 3600 for a specific date. I am unable to understand how to interpret the resulting table. I am assuming the rows and columns represent latitude and longitude intervals. But I am not entirely sure of what the range is. I am a litle confused about how to interpret this. Any tips regarding this will be helpful!
Generally, for a specific date, products from remote precipitation sensing will result in a matrix, which is consistent with the described. To ensure that it is this result that you are seeking, it is interesting to use a visualization tool for this data, the use of ncview or Panoply can help in this regard. If you use linux you can install and use ncdump, the understanding of the data is broader.
Hope this helps.
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Dear all,
I have prepared rainfall datasets for SWAT MODEL using 0.25 degree IMD long term gridded rainfall data,
but as I am using it in the model, it is rounding off the co-ordinates value.
eg:- for the latitude 19.75 and longitude 78.50, the name given to the file is PY1975X7850,
but in the textinout folder, the .pcp file for precipitation is rounding off the coordinates to 19.8 and 78.5.
If it is taking co-ordinate values to 1st decimal place only, then can't we use the 0.25 degree rainfall data in the input?
also it is not displaying the input data in the same format.
Kindly, refer to the attached video to understand the query.
Any valuable suggestions are highly appreciated.
Thanks.
Try 0.2 or 0.3, more decimals don't accept me either.
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What method would you recommend me to carry out a rainfall-runoff analysis with "limited" data (Monthly rainfall [series of 71 years], soil map, LULC map, DEM)? I wanted to use the SCS-CN method but I don't have daily precipitation data.
Feel free to ask if you have any doubt.
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I am doing a small research to review the water related open source tools / software (e.g FREEWAT).
if you have used/developed/ heard of similar tools,please share it with me ?
Yes USGS based softwares eg MODFLOW, Modelmuse, mt3dms, modpath. check their website for more info. All softwares are free and open source
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I am new to HEC HMS. and i am thinking to perform rainfall runoff modelling of a basin near my area using HEC HMS. The data i have is rainfall time series data and flow data of my outlet point. I want to estimate the discharge and compare the discharge obtained from the model to that of the real observed data..how can i perform the modelling without using soil data as i dont have any soil data or soil classification data of my region (for SCS CN method)?
You actually do not need a soil map to set a HEC-HMS model or to calibrate it. It is a conceptual model, so lot of things are approximated. Of course you can use soil and land use to get the Curve Number and other related parameters in GeoHMS but during calibration they are likely to change also. So, a better idea is, do a literature search, start with reasonable values of soil related parameters and do the calibration and validation for streamflow simulation.
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Hi. I need an open source QGIS friendly software to model runoff in a big basin in Africa (17.000 km2). I know how to do it in Hec-Hms but it seams a bit amateur, because the choice of CN depends on user criterion. I would prefer to use a software that use DEM to calculate runoff. In the other hand, and as far as I know, Hec-GeoHMS works only with ArcGIS. Am I right?
Can someone tell me the pros and cons of IHACRES, TOPMODEL and EPA BASINS/HSPF ?
Hi,
SWAT+ fits for your goal. The following paper explain step by step simulation process:
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Rainfall Runoff modelling by using Qgis Watershed
Hello Amit,
You may use the ArcHydro toolbox version in the QGIS for estimating the catchment runoff. Also, you can go step by step, by delineating the catchment outlet, then the FDR, Flow accumulation, and drainage area for the given catchment. Also, you can use the SAGA toolbox for the same. The following links may also be very useful for you:
Cheers
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Here is the FAO Dependable Rain Method to computes MONTHLY effective rainfall
Pe = 0.8 P - 25 if P > 75 mm/month
Pe = 0.6 P - 10 if P < 75 mm/month
Where Pe is the monthly effective rainfall and P is the monthly rainfall
If I want to use the same formula to compute DAILY rather than Monthly Rainfall, can I do that?
DailyPe = 0.8 DailyP - 25 if daily P >2.5mm/day (or 75 mm/30 days)
DailyPe = 0.6 DailyP - 10 if daily P < 2.5mm/day (or 75mm/30 days)
Where DailyPe is the daily effective rainfall and DailyP is the daily rainfall.
This data has been of interest to me as well.
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This error apears only in subasins with a value superior than 19, 682 in the initial abstraction in the method SCS Number Curve.
I think you should not select any method for initial loss or data which you inputted for initial loss for these basins which are shows in error.
you should select the method for initial loss and add appropriate data for selected methods and run again.
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Raindrops falling on the soil
I do not think that this material exists in one of the research laboratories in Algeria. Maybe you have to look at the meteorological office. It may be equipped with such a device.
Regards
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Coefficient of determination R^2
Coefficient of Determination and Nash-Sutcliffe Efficiency are based on least squares so give greater weight to the peaks. A high CoD can indicate the peaks fit well but not the recessions. You can get a better idea of the fit of the recessions by taking logs. There are other measures you can use if you trawl through the literature however I used a combination of NSE and logNSE to indicate the fit of my models when working on my PhD. However what value to pick is a very good question - the answer to that is dependent on so many factors and is often a case of as good as you can get given the uncertainties involved. Good luck. It is probably good practice to determine your limits of acceptability before you start to model then throw out any models that don't comply - again trawl the literature particularly the work of Keith Beven.
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See ⬇️, the upper bar has darker colours for larger errors, does it help the assessment of the agreement of obs (green) vs sim (red)?
Ex using different 🛰️ 🌧️ products, including #SM2RAIN https://www.earth-syst-sci-data.net/11/1583/2019/
here the Matlab code with an example of data for making the figure
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I have eight rainfall events with length of 476 days. i want to predict the peak discharge and peak time.
Use Microsoft Excel, which has a wide range of functiona
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Hi all,
I want to run a runoff simulation in a catchment and almost finished my model in python but, my concern is how to measure the impacts of an increase in 20% of the rainfall in the catchment. Should I increase the original rainfall dataset by 20%? or should I code the increasing part independently?
Thank you very much for your help.
Hi Oswaldo,
and Jose Pablo Ortiz Partida ; why would you like to estimate the effect of changes (only increases?) in rainfall on the runoff? Because of the expected effect of climate change on rainfall patterns? To determine the sensitivity of the runoff to rainfall changes?
In the first case it would be good to use outputs of different Global Climate Models (GCMs) for different Representative Concentration Pathways (RCPs) to assess how for instance rainfall and temperature will change in the area of interest. You then will need a downscaling method to obtain rainfall and temperature (and other meteorological variables) at the catchment scale (instead of the coarse GCM scale). Furthermore, bias correction might be needed.
In the second case, you can evaluate the changes in runoff or streamflow due to different rainfall changes and assess the sensitivity, for instance an increase in rainfall of 20% might lead to an increase in streamflow of 20% as well, but also might be amplified to an increase in streamflow of e.g. 30%.
Good luck,
Martijn
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Hello everyone!!
i'm predicting the future rainfall using SDSM Software.
while calibrating (Period 1970 to 2000) the model for, conditional monthly frequency, SDSM is giving an error says " An error has occurred- please check all the selections. overflow has occurred ".
checked for the Predictand length it looks perfect for 366 days a year setting.
Predictors are Canadian Based NCEP-NCAR (1961 to 2005) of the box (27x , 41y) seems correct, all the variables appears while calibrating.
not able to Debug please do help.
check the Attachment for the error message.
Hello Sir, I am also facing this problem. can You please suggest me the solution.
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Hi,
I have a question for all the soil scientists and geo-hydrologists around.
We want to model the runoff behaviour of a couple of watersheds where some soil and water conservation measures will be implemented (something like small trenches to retain runoff).
Our model is something simple and we are building it for an area with little data available (thus the need to stay simple). We want to roughly estimate how much additional water (runoff and direct rainfall) can be captured by the soil and water conservation structures. The model is a simple water balance for which we need infiltration values (measured with mini disk infiltrometer), which in turns is influenced by soil texture.
We have collected quite a number of samples at surface (0 to 20 cm) and subsurface (20-50 cm) for this. Here is my question for you:
When on a budget constrain, which depth would you prioritize to characterize texture - surface or sub-surface?
Our gut feeling is to prioritize the surface samples, but i would love the opinion of some scientists with hands on experience (possibly with some references to prove the point).
Any thought on this would be much appreciated!
Thanks a lot everyone,
Francesco
The priority would be for the surface layers. If low hydraulic conductivity layers are expected in the subsurface layer, the importance of characterizing these strata would be increased.
With budget constraints, it might be a valid idea to prioritize field infiltration testing to calibrate empirical models, in addition to soil density and macroporosity.
An additional note: in certain oxisols, texture is not a determinant of infiltration capacity, but rather soil structure (granular), which results in high macroporosity. In these cases, even for clay soils but with granular texture, the infiltration capacity is high.
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It can be lumped to a catchment level (with average rainfall and % of land cover types e.g. forest, agriculture, urban) or raster cell based. I agree that, there are many other factors such as topography, soil type, evaporation/evapotranspiration, distance to reach as well as daily/event rainfall distribution that influences the river discharge. But at the moment, the purpose is to compare the net change in river discharge (or runoff) in relation to change in rainfall and/or land use land cover only without needing to specify other information.
I tried the Soil curve number method using land cover and hydrologic soil group, but found it not suitable for monthly or annual data as the response for various amount of rainfall differ a lot and it is aimed for event level runoff estimation.
Thanks a lot for the help
Dinesh
if you search in the literature you will find many examples of lumped models based on stepwise multiple regression that include rainfall , landuse, evapotranspiration etc. I published a paper (sometime ago) Rainfall-Runoff Relationship and Water Budget for Zarqa River Basin I will add the full text to my profile ... hope that help
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Rainfall Runoff Modeling Using HEC-HMS
Go to "Geo-processing--> geo-processing options --> unclick background processing. "
Then re-compute river slope
This should work fin
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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
@Vasker Sharma, you can use the autocorrelation fuction syntax in R,that is acf (), assuming you have a monthly data series of a data frame called Rubi, to check for auto correlation at lag=1 in the January series of Rubi in R you type as follows;
acf (Rubi\$January,lag.max=1)\$acf pressing your enter key will display the autocorrelation plot at lag=1,you will clearly see the limit line marked in blue,if your output crosses the limit line in either the positive or negative side of the divide then you can say that the January series of the data frame called Rubi is statistically significant at lag=1.Modified Mann-Kendall (MMK) is then recommended,in such case i will recommend the Bias Corrected Pre-whitening (BCPW).
Best of luck
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I have a question about your work (Fuzzy Logic).
In forecasting something using FIS toolbox (in matlab) how to use previous output (T-1) as one of inputs?
What model you are using with Fuzzy Logic and what are the inputs and outputs of model.
Your question is not clear. If you clarify then I will be able to understand and attempt to suggest if it is possible.
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I am trying to calibrate a hydrologic model for a large watershed in central Mexico(Lerma). I found several stream gages in the watershed, but hourly streamflow data from the gages is not consistently available till 2018. Also, I haven't been able to find any historical rainfall data. To collaborate my model, I need both rainfall & runoff data.
Can someone suggest any source to download rainfall and runoff data for the central Mexico-Conauga?
I would truly appreciate any help.
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What data do we need?
I got 35 years of daily data of rainfall and river discharge.
I am working on this project for my final year research project in civil engineering.
I think most kinds of ANNs could well simulate the river discharge with the previous observed streamflow and current rainfall data. But those works highlight the predicted discharge only. Hence, if for something new, your point should focus on if the LSTM can reasonably reflect the mechanistic processes. Specifically, the soil moisture has the memory of previous wetness in a watershed, which may be suitable for the function of short-term memory in LSTM. It means soil moisture productions made from remote sensing or land surface modeling may be useful for your research project. Moreover，some of my work published in 2013 and 2014 could be helpful, as well.
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The soil erosion rate level is different across the region, what is the acceptable erosion risk level for construction activity ? Any reference or comparison between country or region ?
Dear Abdul Rahman Mahmud
A paper is attached. It can be useful for your question.
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Hi, I am working on road improve project in Africa Region. Of course we are going to project main road and its infrastructure system. We are developing main drainage and support drainage systems. Because of project site morphologic and climate conditions, runoff harvesting is main issue for our project. We will use roadside drains, outfall chanel, ponds in our project. I'm wonder what you think about following topics:
• How do you think we should calculate ponds-outfall channel shapes, lengths, diameters ?
• How do you think we should solve complex interaction between culvert or pipe structure under road and roadside drains (ponds-outfall channel) ?
Thanks.
Sorry, I could not tell from question that you were licensed engineer. Your question direction seems to be using the road system and access potential to develop water storage. Water storage can have many benefits, but also effects and liabilities. Installing ponds, dikes, dams, channel modifications are various forms of hydrological modifications. If volume of water storage is important, identifying preferential dam locations may be important. These modifications can affect various aquatic habitat and channel functions, water quality and sediment transport; benefits possible for water uses as irrigation, fire control, perhaps recreation, fishing, etc. As with any project with intent to modify hydrology, it is best that decision maker be presented with full assessment of effects to make informed decision and as well identify areas of mitigation or design concerns. The larger the drainage size (named stream, watershed, or basin scale), the more complex and detail may be needed. If rural areas are involved and downstream, failure of structures are unlikely to have same effects as if failure would flood downstream communities or urban areas. I would make sure I have reviewed drainage land use, geology, soils, rainfall and streamflow records. Below moderate to large dams, culverts and other crossings are unlikely to be sufficient unless specifically designed for bipass or overflow.
I would consult with fisheries biologists, botanists, etc. I would make sure equipment used is washed as needed to avoid transfer of invasive species. I would make sure ponds have overflow channel or armored to allow overflow. If roads are used to develop permanent ponds or lakes with control to manage flow, I would design road much like a dam, with clay core, compaction, etc., design armored overflow. It is not unusual for many US areas even with great hydrology data, for the design storm uncertainty to be plus or minus 40%. I am unfamiliar with storm severity data for Africa, but uncertainty can be a significant factor. For many large stream systems, providing for aquatic organism passage is an important concern, so if you are installing culverts, they need to be designed for outlet control, submerged. I am used to the team approach to projects, but consulting with a variety of expertise, specialists, landowners in vicinity can provide both benefits and perhaps frustrations, depending on your opinion, and the direction of decision maker or developer.
We use various methods to allow for dependent species and instream flows, depending on the circumstance. In most instanced we would recommend bankfull flow releases every year or two, to maintain channel capacity, and some use the 7Q10 flow as the minimum flow released from control structures to maintain perennial flow, in addition to any downstream needs with water rights.
There are guides on internet if needed to address not only road construction, design, but also size of sediment basin, plunge or scour pool, pond, dike, dam, culvert sizing nomographs, erosion control, etc. Some of your training and texts probably covered topics, but pulling it all together into project form to fit specific circumstance adds complexity. I have learned, especially in relative flat or inaccessible terrain, the value of LiDAR adds substantial topographic and channel detail, improves identification of hydrologic boundaries, georeferencing streams and estimating stream types and morphology. DEM Contour intervals of less than 1 meter may be available for improvement of draft design before field survey Confirmation.
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The best design consideration in design sediment basin.
A few ideas. The size of basin with respect to drainage area and expected storm flow. The residence time for suspended solids to settle before discharge. The length or path distance that sediment would have to move within the sediment basin before being discharged. The type of sediments - storing clays is especially difficult to settle without sufficient storage time. Maintenance of sediment basin - will it be maintained on regular schedule, or just built and left. Sediment sources and activities in watershed. If capacity is exceeded, would the sediment basin fail or have emergency overflow? How long is sediment basin supposed to operate, short term associated with an activity and mitigation, or long term due to recurrent sediment issues and need for low sediment to support downstream uses, water treatment, etc. Consider type of upstream contributing streams - gullies and steep gradients deliver sediments efficiently, while upstream braided streams are result of high sediment load, and they also tend to be accumulating sediment (aggrading). What is potential for contributing upstream activities such as channelization, road development and land clearing, urbanization, etc. If not familiar with Roehl (about 1962), he developed sediment delivery ratio from drainage size using ponds and dams. His results suggest that the larger the contributing drainage area and associated reservoir, the greater efficiency at removing sediments, and one might also assume that larger watersheds often have ability to store some sediment on their floodplains.
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any software suggestion for modeling precipitation on sandy soil
and if it is easy to use better
What exactly are you looking to model? Infiltration? slope hydrology? geomorphology?
I've used 'CAESAR-Lisflood' successfully for a range of sandy slopes to simulate short and long term erosion and sediment loads in runoff. 'SoilCover' is good for infiltration. Good luck!
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Hi everyone,
Can anyone guide me how to use SCE-UA to get the optimized value of parameters, especially parameters from rainfall runoff model. I found one SCE-UA script written in matlab language, however, I can't find any part of the script is related to parameter of model.
Dear Jean,
Thanks for your explanation.
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Is there any model available to predict surface runoff temperature?!
Hi Saber,
Depending on the level of detail needed and the amount of complexity you are willing to employ, there are a number of possibilities. My experience is mostly from working in cold / temperate landscapes, so I am not exactly sure how relevant these ideas will be to your situation. Here are the possibilities for simulating water (runoff) temperature on a given day (T_w(t)), from most simple to more complex:
(i) The average air temperature (T_air(t)) or zero degrees, whichever is greater.
T_w (t) = max(T_air(t), 0)
(ii) Lagged air temperature
T_w(t) = (1/k)(T_air(t)) + ((k-1)/k)(T_w(t-1))
The "Nordic" HBV model I have used in the past uses a default lag factor (k) value of 30
(iii) A process-based soil temperature model, I have used Rankinen et al. (2004) and been satisfied with the results
(iv) Any of the more complex, process based river temperature models (see, e.g. Webb et al. 2008)
Rankinen, K., Karvonen, T. and Butterfield, D., 2004. A simple model for predicting soil temperature in snow-covered and seasonally frozen soil: model description and testing. Hydrology and Earth System Sciences Discussions, 8(4), pp.706-716.
Webb, B.W., Hannah, D.M., Moore, R.D., Brown, L.E. and Nobilis, F., 2008. Recent advances in stream and river temperature research. Hydrological Processes: An International Journal, 22(7), pp.902-918.
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As part of my research, I am modelling runoff discharge on a rural watershed. I would like to activate Land Use Update with SWAT. I am using ArcGIS 10.3.1 with ArcSWAT, along with SWATCUP 5.1.6 for automatic calibration. I used SWAT LUU tool (see https://saraswat-swat.rcac.purdue.edu/swatluu) to prepare inputs lup.dat and relevant files for 3 differents land use scenerios (2004, 2009 and 2017). My simulation goes from 2004 to 2017, with one year warm up (2004).
I noticed that when I run SWAT-CUP, it seems to find lup.dat, since deleting any of the associated *.dat files containing HRU fractions (HRU_FR) values returns an error. However, during the auto-calibration process, *.hru files are constantly edited, but their HRU_FR (first line) does not change. As such, it seems that land use update does not work.
Are there any recommended guidelines or anything I have missed ? In case any information is needed upon this, I would be glad to provided them. Thanks in advance.
Roland.
Hi Roland,
Do you mean that the SWAT_CUP copys the lup.dat but It does not copy the associated files (HRUs fraction files)?
If this is the case, might be you could try to copy the land use change fraction files to the working folder of SWAT_CUP for it.
About the .hru changing constantly but the HRU fraction does not change. I think this is because every time the parameters was change, all of the file will be rewrite by SWAT_CUP. SWAT_CUP does not need to change the HRU_FR in .hru file because SWAT will change it according to the information in the lup.dat file.
I also create an R script to generate input files (TxtInOut) for SWAT (new HRUs emerings due to land use change will also be consider and you can also interpolated you HRU fraction at any time). If you interest in using this script, please let me know.
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Over the years, there have been numerous techniques developed to analyse baseflow recession as well as derive a recession constant, K (Hall, 1968, Vogel & Kroll, 1996; Kienzle, 2006; Dijk, 2010; Beck et al., 2013).
How you do select the range (start and end points) on the recession limb to derive the recession constant / do recession analysis?
Why did you use that rule? How is it advantageous over the others?
You could also look at the papers by Lamb and Beven 1997 and Beven et al 2011 on generating a master recession curve
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Is there any way to compute effective rainfall in Australia ? Like the the SCS-CN method for the US. It has to be specific to Australia, preferably from observation/experimentation in the field (empirical equation). I am looking for something different from the Dependable Rain (FAO) or the USDA soil conservation service.
The concept of 'effective rainfall ' is irrelevant for most environments. What is effective rainfall in an urban area? 'Effective rainfall' is the amount of rain which is 'used' to produce a crop or fill a reservoir. It is meaningless when applied to an area much bigger than a paddock - and even then if the terrain is variable in slope or soil, or the farming system is different, the calculation becomes very difficult very quickly.
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I'm searching for some softwares (or methods) that can help me to model the fate of pharmaceuticals (or pesticides/chemicals) from runoff in agricultural soil.
I tried to use RZWQM and PRZM but without satisfying results; other ideas?
Dear Andrea
Take a look at these files and link. Hope it might be useful.
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Does anyone has a simple empirical formula to compute Daily effective Rainfall for any location in Thailand?
Thanks
Hi Daniel,
Water in the root zone may be measured by sampling and oven-drying the soil before and after every shower of rain. The increase in soil moisture, plus evapotranspiration loss (ETa) from the time the rain starts until the soil is sampled, is the amount of effective rainfall. After heavy rainfall evapotranspiration can be assumed to be at the potential rate during the short period from cessation of rainfall until the sampling time. This can be taken as 0.4 to 0.8 times the evaporation value of the Class A Pan
ER = M2 - M1 + kp EoER = effective rainfall Eo = Class A Open Pan evaporation value M1 and M2 = moisture status in the effective root zone before and after rain, respectively kp = pan coefficient
The method takes into account the soil and the crop characteristics. The determination is simple and accurate but it may involve errors due to soil variation; the sampling errors may range from 5 to 40 percent. The method is also laborious and time consuming. The use of neutron probes reduces the drudgery of periodic soil sampling, but these are costly methods for routine purposes and also subject to sampling errors
Best Regards.
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hello everyone!!!
we are doing rainfall runoff mdelling Using SWAT.
we have two gauging sites where levels are measured.
one locations is weir and another one is controll crossestion.
both the locations are very close to sea. levels measured at both the sites are affected by the sea level variations.
i would like to correct these levels before using it for callibration and validation (we have stage disgharge relationship to convert levels into discharge) .
Note: we dont have the sea levels data.
I have not tried to do this. Most places have approximate tide elevations by date and hour calculated by moon influence. Wind speed and direction can affect tides. You should probably determine the exact elevations when tidal influence begins, and how much time after especially high tides like new or full moon does it take to drain the brackish water and return to freshwater. Since freshwater is less dense, obtaining salinity values is unlikely to help due to poor mixing. During non-storm periods, you can probably recover flow data by smoothing the recession curve before tidal influence with recession curve when tidal influence is gone.
If tidal influence is regular, such as twice a day, you might be able to use the past daily tide tables and using periods of low freshwater flow, determine the influence of the tides in reversing flow direction, flooding weir or upstream sections or floodplain with tidal water, and then the time it takes when the tide drops to return to baseflow. You might need to calibrate flows over a weir that has backwater, rather than a free drop in elevation. The flow velocities through culverts are different between inlet control, and outlet control, partially to fully submerged.
If your long term goal were only measuring freshwater response at these sites, an efficiently placed dike downstream at high tide elevation may be used to control salt water entry. A water control structure sometimes called a trunk, can limit salt water entry, but allow for freshwater passage at lower tide. Another option could be to raise the weir outlet so salt water influence is avoided or less frequent. Some of the advantages of a weir are lost if the v notch control is affected by backwater. As the backwater elevation increases, the effective cross section of the notch is reduced from free fall by gravity to push back by water, velocity slows.
Periods of storm hydrographs affected by high tides would be most difficult to recover. Storm hydrographs not affected by tides will be the best data. Flow data affected by tides will likely be of lesser quality. Placement of a transducer or other water level indicator upstream of tidal influence and downstream of the weir and/or gauged cross section would help differentiate better the timing of salt water influence and help improve quality of recovered data.
I do not know of any model that can help, but would not be surprised if there was one that could be calibrated or modified to assist. If you have stream gauging equipment or an agency such as US Geology Survey, I think a respectable level of calibration and recovery of flow data would be possible.
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Hello everyone!!
I would like to know , How to convert hourly stream flow discharge to daily discharge ?
The discharge data thats measured hourly in m3/s can be averaged over period of 24hrs ( average of 24 values) to report mean daily discharge in m3/s.
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Dear All Prof, lecturer, and researcher. I am Ali Rahmat, Master student of Gifu University. I am in confuse condition, I get home work from my supervisor to separate direct runoff and baseflow but I only have total runoff (water discharge). I try to approach used electric conductivity and water temperature data but still can not prediction when direct runoff stop.
Did any equation to prediction direct runoff and baseflow? or another technic to separate?
Thank you very much
The "lfstat" package on R looks quite good too, and provides scientific references. But the WHAT website is probably the easiest.
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I'm currently trying to study the flash flood risks in an ungauged area. Is there a recommended way to calculate the daily accumulated rainfall data in a certain location using satellites like TRMM ?
Hi Omar,
I would suggest looking at GPM data in addition to TRMM, GPM being a much newer product with a higher spatiotemporal resolution. NASA's Giovanni web portal (https://giovanni.gsfc.nasa.gov/giovanni/) is a great resource to download information from both missions, since you can do it in gridded format or with post-processing that allow things like obtaining area-averaged time series.
Also, since you are interested in flash floods, aren't daily estimates too coarse for that purpose? TRMM has an hourly resolution product and GPM has one with a resolution of 30 minutes (also available from Giovanni).
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