SWAT model - Science topic

The influence of elevated atmospheric CO₂ (eCO₂), particularly under future scenarios exceeding 660 ppm, presents a critical uncertainty in modeling the water-food nexus. eCO₂ affects both plant physiology (e.g., stomatal conductance, transpiration, biomass accumulation) and hydrological processes (e.g., evapotranspiration, runoff generation), making its integration into modeling frameworks increasingly important.

I am currently exploring which hydrological and crop growth models are capable of incorporating eCO₂ effects, and to what extent they represent the associated physiological and hydrological mechanisms. Moreover, I am interested in understanding the complexity of these models in terms of how CO₂ response functions are embedded in their algorithms and equations.

Could you recommend hydrologic and crop models that can simulate eCO₂ impacts realistically? How do these models differ in their assumptions, parameterization, and overall representation of CO₂-driven processes?

Your insights, experiences, and any relevant literature would be greatly appreciated.

I am working on enhancing the SWAT+ model for my PhD research and need to modify its source code. Could anyone suggest:

Any guidance would be greatly appreciated. Thank you!

My research is on the impact of climate change on soil moisture dynamics in forest and grassland areas using the SWAT model. I need someone grounded in this area to mentor me. I am also open to collaborations and coauthoring. I tried using Hydrus-1D but it was a bit complicated and so I want to explore the SWAT model.

I have calibrated my SWAT model with monthly observed flow data, and the NSE coefficient is as high as 0.85 at monthly scale, while when I plot a FDC curve with daily flow data, it does not match well. Generally, the model overestimate the peak flow for a flood process, and the variability of simulated flow is much higher than that of observed, therefore, I want the simulated flow to be more smoother.

I think the SURLAG parameter from the basins.bsn file should be responsible for this.

I have changed the SURLAG from the default value of 4 to 1, 8,22, but it does not result in any difference in FLOW_OUTcms. I wonder why?

Is there any other responsible for this ?

Actually I am looking for SWAT+ modeling help book/video to understand the basic processes happening in SWAT+ with great details.

at the endpoint of the watershed. The Gaging point is not there.

Hi there, I am having an issue delineating the watershed. I am trying to load a .tif file and when I click 'create streams' I get the following error (attached). It's not a problem with QSwat+ software because I was able to follow tutorials online using the software, without issue. Any help would be greatly appreciated.

Edit: the error reads as follows:

*** Problem with TauDEM /Users/user/SWATPlus/TauDEM5Bin/pitremove -z /Users/user/Documents/Masters/Swat+/CGD Pre Harvest/Preharvest5/Preharvest/Watershed/Rasters/DEM/DEM_IRL_ITM.tif -fel /Users/user/Documents/Masters/Swat+/CGD Pre Harvest/Preharvest5/Preharvest/Watershed/Rasters/DEM/DEM_IRL_ITMfel.tif: please examine output above. ***

Hello friends, I'm trying to run QSWAT and I'm after step 3 on the simulation process , setup my model from 2001 to 2005 with NYSKIP 2. Chose daily because my data prepared like that. Before that I setup my WGEN_user , pcp and tmp data. When I click run SWAT I get the following message - forrtl: severe (24): end-of-file during read, unit 25, file D:\Transffered\N\Z-Zone\BAS\Ogosta_database_model\SWAT_Model_Final\test\Scenarios\Default\TxtInOut\000010000.sub

On step 1 of the model I merged several subbasins because they were very small and I joined them to bigger ones. Could that be the problem?

As you can see from picture 2 file 000010000.sub is empty?

Please share possible solution.

Dear Community,

I would like a question regarding the use of Partial Least Square Regression Analysis. Basically ,I am confused in units. For example, I have Year 1, Year 2, Year 3 land cover and Water Balance Components. The units of Water Balance Components are "mm", while the units of each landcover type for year 1, 2 and 3 are in square Km. I am confused how the different units will perform the PLSR test.

Either, I have to use the % difference in each Year or % of particular landcover type to the total area of the basin and similarly convert the water balance variables from "mm" to percentage.

Looking for a guidance. Please teach me.

Regards

I created a QSWAT hydrological model and the simulated daily runoff values in cubic meters per second are extremely higher. Does anyone have an idea what is causing this problem? #QSWAT #Hydrological_model

hi

i have calibrated a snow/glacier-fed mountainous watershed.

The calibration results are good with R2 and NSE >0.80 and p factor 0.77 and r factor 0.71, PBIAS 7.5

I have got the following values.

v__SFTMP.bsn                  -1.750000 v__SMTMP.bsn                  -5.850000 v__SMFMX.bsn                  1.100000 v__SMFMN.bsn                  2.100000 v__TIMP.bsn                   0.083333

Hi everyone,

I wanted to know what is the land use classification code used in the lookup table for Mixed Dryland Forest and for Scrub & Shifting Cultivation in the SWAT model.

Thank you all.

Majid.

Hi Everyone,

I am going to be carrying out a water quality study for a catchment that has a reservoir at its outlet and its majorly covered by vegetation, with some shifting cultivation and there are a few local villages, so there is some point source and non-point source pollution. So, I wanted to know, can SWAT model the following water quality parameters? And is there any better hydrological model to use for modelling these parameters?

1. Dissolved Oxygen (DO)

2. Biochemical Oxygen Demand

3. Chemical Oxygen Demand 4. Ammonia Nitrogen as N (NH3-N) 5. Total Suspended Solids (TSS)

6. Total Nitrogen as N (TN) 7. Total Phosphorus as P (TP) 8. Percentage of DO Saturation

9. Coliform

10. E. Coli

11. pH

12. Fluoride

13. Chloride

14. Iron

15. Manganese

16. Aluminium

I appreciate the feedbacks.

Thank you all,

Majid.

I have a monthly dataset of GLDAS evapotranspiration (version 3.6 a with 3-hourly temporal resolution). The conversions I have come across suggests multiplying the dataset values with 86400*(Number of days in the month) which sounds reasonable however the dataset values are all greater than 1 thus, this conversion will result in unrealistic ET values (>86400 mm at least).

So, I was wondering if the monthly dataset are actually daily ET values averaged over the month, making the actual units of the dataset kg/m2/day (mm/day) which require multiplication only with the number of days in the month.

Please provide your opinion over this.

But I have found much HEC HMS better compare to SWAT.

I am currently working on developing a SWAT model for a basin. After I have developed the model and figured out its hydrological components, I need to compare my work with an already published work. Can someone give me suggestions on how to proceed with my paper? or give me links to similar works so that I can get some ideas! Thank You.

Hello everyone, I am doing calibration of Flow for my watershed. My concern is, I am stuck with the value of NSE, R2 and PBIAS. only the p-factor and r-factor changes into decreasing value.

How to decrease the value of CN2 and ALPHA_BF? These parameters belongs to the most sensitive parameters in my model.

What do I need to check to verify these values?

Thank you!

Hello everyone, I am having a trouble to understand why does my point source located on downstream affected my upper stream data for flow?

Does anyone know any idea why it does?

Thank you!

In rainfall-runoff modeling, it is often not possible to find the unique best parameter set, different parameter sets may be given similar good results during calibration. To reduce uncertainty and to define the optimum parameter set, it is a fundamental analysis of model parameters.

How SWAT model computes the initial soil moisture (SWo) from the general water balance equation SWf = SWo+summation of (P-ET-Q-DP-GW).

Could you tell me some websites to download temperature data as input to a SWAT model?

Dear All,

 I hope this message finds you well. Actually, I have a problem with the irrigation management in SWAT model and I would appreciate if you can consult me on this issue. In my SWAT model I defined the irrigation manually in mgt files using mgt_op=2 and introduced the values of IRR_AMT for each subbasin and HRU  and the source of the irrigation one by one based on available data. I have three kinds of irrigation sources which are applied in my model: reach or dam or shallow aquifer. For some subbasins and HRUs (for example hru 1 sub1 or hru6 sub1...) the irrigation is defined to be from the reservoir dam but as I checked the OUTPUT.HRU of the SWAT in these regions some parts of irrigation (varied 20% to 80% for some HRUs) are supplied from the shallow aquifer which the value of SA_IRR (irrigated water from the shallow aquifer) shows that in the output file. It is contradictory that in the theoretical manual is also said as follows: For a given irrigation event, SWAT determines the amount of water available in the source. The amount of water available is compared to the amount of water specified in the irrigation operation. If the amount available is less than the amount specified, SWAT will only apply the available water. (ver2009, p 375) Furthermore, I checked the model with different sources added on by one to debug the problem. If all the irrigation source of  a specific subbasin (all HRUs) assumed to be from reach, dam or unlimited source then the  SA_IRR (irrigated water from the shallow aquifer) will be zero but if the shallow aquifer introduced as irrigation source for one or more HRUs of a specific subbasin, the other HRUs can also extract the rest of their irrigation water demand from the shallow aquifer as the SA_IRR will be nonzero. It happened for all the other conditions (IRR_SC=1 or RR_SC=2 or 5  According to the analysis of the irrigation source in my SWAT project, I got the following conclusion: If you define shallow aquifer as an irrigation source in one or some of the HRUs of a specific subbasin, then in all of the HRUs of that subbasin, the SWAT model first supplies the water from the defined source (dam or reach) and then it tries to supply the rest from the shallow aquifer. So I would appreciate if you let me know why the rest of the irrigation demands supplied from the shallow aquifer, whereas the reservoir is defined as source location of the irrigation. The output.hru file for one year of running is attached. Please let me know if you need any further information. Thank you for your kind support in advance. Best Regards,

Hello Everyone

I am facing an error at the running SWAT model simulation step. Showing that error as  txtInOut/ATOM.ATM.

Screenshot is attached . Please help me in this regard.

Working with SWAT modeling in mining regions. The Land Use of the mining region has to be fine enough to understand the impact of change of land disturbance by mining on hydrology.

Hello SWAT users,

I would like to design ponds in the catchment area.  I wonder if in this case it is enough to enter the parameters of the ponds in the .pnd files, or should they also be modificated on the landuse map?

Best regards

Damian

The SWAT model didn't report any errors in the previous operations, but when I click "Run SWAT", it runs not successful(fig1). I open the slr.slr as it tells me , but I don't know how to find the error. One more question is that, whether my chooses are correct in the window(fig2). Can anyone tell me how to do? Thank you very much.

Hello, honorable forum members. I have a question related to ponds, retention tanks, etc. in the SWAT model. What water balance parameters are affected by adding pond parameters in the .pnd file? I would also like to model an increase in the number of ponds in the catchment area. Is it enough to enter new parameters in the .pnd file for this purpose, or do you also need to draw the joints on the landuse layer? Best regards Damian

Respected All

The data which is available at https://swat.tamu.edu/data/india-dataset/ , the file named "SOIL_WATERBASE.7z" on this link has only the raster along with "VALUE" and "NAME" of the soil series, which is taken/subsetted from HWSD_FAO,

But the database file require a large number of inputs of different soil properties, for these soil series like, compaction, number of layers, Texture, Bulk density, Available water capacity, Proportion of sand silt and clay, etc, in the dbf file, which has these columns

OBJECTID

MUID

SEQN

SNAM

S5ID

CMPPCT

NLAYERS

HYDGRP

SOL_ZMX

ANION_EXCL

SOL_CRK

TEXTURE

SOL_Z1

SOL_BD1

SOL_AWC1

SOL_K1

SOL_CBN1

CLAY1

SILT1

SAND1

ROCK1

SOL_ALB1

USLE_K1

SOL_EC1

SOL_Z2

SOL_BD2

SOL_AWC2

SOL_K2

SOL_CBN2

CLAY2

SILT2

SAND2

ROCK2

SOL_ALB2

USLE_K2

SOL_EC2

and so on_____________till 10 layers (if available)

The another file named " soil_HWSD_FAO.7z " has its global raster without any information about the soil properties which are used in input database.

I have sub-setted/clipped the indian raster from the global,

although the global raster was missing spatial referencing,

So if someone is sub-setting the same for their area of interest, then you have to manually geo-reference the subsetted image to use it while creating HRU's.

Kindly share if you have any idea about, the source of the soil properties for these soil series.

I faced two errors while I was trying to rewrite SWAT inputs:

SWAT inputs rewriting: 'SPCON' does not belong to table.:RTE file print error on subbasin:1

column 'CO2_X' does not belong to table

Where can I get future data that can be fed directly into the SWAT model?

I would like to know the procedure of creating soil database for Australian soil classification types to apply in the SWAT model. Most of the global studies used FAO soil database for SWAT model setup but using Australian soil map will generate more accurate result. Please suggest how can I create a soil database or replace 'usersoil' database schema on SWAT2012. Thanking you in advance.

I am selecting an opensource hydrological model to perform a water sustainability assessment at a basin scale, including blue and green water sustainability evaluation and some considerations about water quality. I need an open source, well documented and user friendly open source software. After a first check, I identified two suitable options: SWAT+ and SWIM. I cannot really understand the differences among them. Any suggestion from someone who has already used these models? Thank you for your cooperation.

I cannot seem to get irrigation depth to be realistic (always underpredicts). I have tried manual and autoirrigation, increasing irrigation depth, changing stress factors, withdrawal source, and heat units/date scheduling. No option gets me close to the ~300 mm/yr for peanut/cotton, or ~400 mm/yr for corn. 

UPDATE: Changing the irrigation method from plant demand to soil moisture demand (WSTRS parameter) causes more realistic irrigation depths for my model, but also causes irrigation to occur all year instead of just during the growing season. Any suggestions?

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!

I am using swat model for first time. Now fro usersoil part, i am recording my soil properties by replacing existing data in table. My worry is am i corerct if i use existing codes such as OBJECTID,MUID,SEQN,SNAM and S5ID? By only editin other fields of siol properties. Wuold there be erorr in futuer runing of model?

Thank you,

Abiy

Good day Sir/Ma'am, I am one of the researchers and here's is our research study for our thesis: "Spur dike installation against soil erosion along mandulog river". And we are currently having a hard time looking for what software will be the fit in our research study and we would like to ask for your advice on where to get the software or what other softwares can we use to analyze the data in our study. Any suggestion will be greatly appreciated. Thank you and have a great day.

I would like to know at what height from the ground surface the temperature is measured to the weather data for the SWAT model.

Best regards

I am facing a challenge with the classification of my soil data in order to help create the usersoil database. My soil data was developed using the USDA classification system but I now have to convert it to the FAO code so as to match those provided in the SWAT2012 database to help generate the usersoil table. Could someone explain to me what the second and last numbers  in the code are and where I can obtain it. E.g Af32-2ab-3, Be49-3c-20

The first letters represents the dominant soils, Ferric Acrisol (Af) or  Eutric Cambisol (Be), the third figure is the soil texture class (1-coarse, 2-medium, 3-fine), the small leters indicate the slope class (a- level to undulating; b- rolling to hilly; c-steeply dissected to mountainous)

What does the second figure of 32 or 49 and the last figure of 3 or 20  represent in the code and where can I obtain them?

Secondly, is there an alternative way to create the usersoil table without using the FAO database, could anyone kindly share any useful resources in this regard?  

Thanks in advance!

Regards,

Brian

I have a problem with permanent wilting point WP. According to the formula WP = 0.40 * ((% CLAY * Bulk Density) / 100). My data shows that% CLAY = 5%, BulkDensity = 1.55. After converting, I have the result of 31mm per 1000mm of soil. To my knowledge it should be approx. 110 mm per 1000 mm of soil. Can I enter my own WP content data into the input.std file into the SWAT model?

Greetings

Damian

Hello dear user,

when calibrating, I would like to leave the value sol_z (1) - 300mm, sol_z (2) - 1000mm, sol_z (3) - 1500mm (mainly loess soil in the profile), which I used in modeling. Unfortunately, it is difficult to calibrate a model with this parameter. I wonder if there are any parameters that have a lot of dependency on sol_z? When I set the possibility of calibrating the sol_z parameter, the result was satisfactory. Unfortunately, the values of sol_z (1) - 150 mm, sol_z (2) - 300 mm and sol_z (3) -450 mm. This is not satisfactory due to the fact that the research region has a loess thickness of up to 20 meters.

Best regards,

Damian

I have been using the SWAT model, and simulation has been done several times by changing the evapotranspiration calculation method and the rate of hydrological parameters like Soil Evaporation Compensation (ESCO), Groundwater Re-evaporation (GW_REEVAP), Curve Number (CN2), Available water capacity of the soil layer (Sol_Awc), and Slope range of the area.

So, the annual precipitation is 318 mm, the annual surface runoff is 602 mm, but the annual evapotranspiration is based on the Hargraves method (1450 mm) and based on thornthwaite method ( 840 mm). so why runoff and ET are more than precipitation? it can be acceptable in terms of the water balance?

Any solution or recommendation to encounter it, please?

Hello everyone,

I have setup and calibrated the SWAT model with SWAT-CUP, the NSE coefficient is as high as 0.85 both for calibration and validation periods at five gauge sites. But the CN2 parameter for most of the subbasins are as high as 98, I don't think it's reasonable in the physical sense. I wonder how can I decrease CN2 by modifing other parameters?

Would you please give me a suggestion about which other parameter is equivalent or have similiar effect with CN2?

Thanks in advance.

I am trying to add DEM file for watershed delineation in ArcSWAT, but some error occurred. Can anyone help me to solve this issue...

I am using SWAT 2009 and working on a Godavari basin (India). My main objective is to estimate the monthly runoff. I already ran the model and found monthly runoff but it is overestimating. I used many calibration parameters to calibrate the model i.e. CN2, GWQMIN, GW_REVAP, REVAPMN, GW_DELAY, ALPHA_BF, SL_SOIL, LAT_TIME etc.

I am putting all the values in the parameter range, but I did not find any changes in the simulated runoff. What should I do?

I wonder how many HRU areas should I do in my catchment area. The catchment area of 30,000 ha is divided into 31 sub-basins. Upland area with a slight slope. 14 landuses. The 3 landuses are separated by the split landuses function into 6 additional landuses. Total landuses there are 20. 32 types of soils. 5 groups of terrain slopes. I used filter by landuse, soil, slope (thresholds) 15% landuses, 15% soils, 10% slope. I received 1,000 HRU areas. Is it correct? Should I accept fewer HRU areas?

Quantifying groundwater recharge in arid and semi-arid areas is a very challenging task because recharge amounts are small in comparison with the resolution of the investigation methods. Additionally, it depends on soil characteristics, geology, topography, land cover characteristics and land use, besides being affected by the temporal variability of precipitation and other hydrometeorological variables under arid and semi-arid climates. Several watershed models used to quantify recharge generally provide recharge estimates as a residual term in the water-budget. Which means that the estimation accuracy of recharge is controlled by the measurement accuracy of the various other parameters in the water budget. Moreover, according to the literature, daily time steps are desirable for estimation of recharge because recharge generally becomes a larger component of the water budget at smaller time scales.

How could we minimize the uncertainties accompanying the estimation of groundwater recharge under semi-arid conditions using SWAT model at small scale (around 350 km2 area)? Should the SWAT use be coupled with any other techniques or models (like Hydrus-1D) to get best results? Are you aware of any studies that have used SWAT to estimate groundwater recharge, or the impact of climate change and/or anthropogenic activities on groundwater recharge under arid or semi-arid conditions?

Hi

I have a SWAT-CUP calibration question.

When calibration is performed using SWAT-CUP, the correlation coefficient and NS value are decreasing rather than before calibration.

The correlation coefficient before correction was 0.9 or higher, and the NS value was also observed as 0.7.

Through correction, the NS value was increased and correction was carried out.

The Excel graph(figure file name 9) before calibration is based on the \Scenarios\Default\TxtInOut\watout.txt file in the SWAT project folder.

Please advise if I am doing wrong corrections.

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?

Can anyone explain the steps in SWAT modeling and to proceed ahead.

I am looking for surface and groundwater modeling using SWAT.

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

Hello and have a good time When running the SWAT model, I encounter the following image error. Is there anyone who can help me solve this problem?

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?

Dear Colleagues

I am using the SWAT model in an irrigated basin where I wanna specify the Irrigation database for major crops (sugarcane, maize, rice, wheat, and cotton) in SWAT model simulations. Does anyone suggest to me "how to address the crop management data including growing, harvesting date, and irrigation amount applied for each crop"?

Your's help will be really appreciated.

Thank you very much.

Kind Regards!

Arshad

I set up, run and calibrate SWAT model.

I want to test BMPs scenarios for the next step, but I don't know how to do that.

I have to prepare new input files or I can do on the ArcSWAT interface.

How can download the precipitation data from INDIAN METEOROLOGICAL DEPARTMENT(IMD) or Centre for Climate Change Research (CCCR) of Indian Institute of Tropical Meteorology

(IITM), Pune.

Could you refer to any other web sites?

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?

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.

Hi everyone need your help.thank you

input types and formats...!!!

Why the number of weather stations is different between "pcp1.pcp" and input weather data?

I have input 23 stations, but it only 8 stations in the "pcp1.pcp" and "tmp.tmp".

Could you help me? Thank you, very much!

Hi,

I am delineating my watershed for the first time in ArcSWAT 10.3. But when i try to attach my DEM file it gives an error 2147217383 ( failed to copy raster dataset). I have tried to check the permission of folder where DEM is present and everything is fine. DEM coordinates are in Projected UTM.

Can someone guide me through thus error.

Hello, Has anyone conducted calibration using the SWAT model? If so which method did you use? And was it successful ?

Hi Everyone,

I want to model the inputs of nutrients from septic system (septic tank and pit latrine) into ground water or surface water. could SWAT model this issue?

Any help will be appreciated

Thank you in advance

Hello everyone,

I have a calibration problem. After a few iterations of the model, I get a chart with high flows at the beginning and low flows at the end that do not match the measured flows.  I wonder if I have an error in the flow data somewhere or I am doing some calibration error. I would be very grateful for your help.

Best regards

Damian

Hi

I am friends I am calibrating stream flow using SWAT-CUP. While altering the parameter ranges to get the best simulated result, how to fix ranges for parameters.

Please help me in this

Regards

Dagani

I have my watershed file, when i upload the projected Soil Map for HRU analysis, SWAT gives error "there is no overlap with watershed gird" can anyone please answer me how to remove this error.

Dear All,

SWAT model needs volume of water and spread area when the reservoir is filled to the emergency spillway and principal spillway. In case of reservoir with radial gates the following data are available-

Crest Level of Spillway = 407.51 m

Height of Spillway Gates (Meter) = 15.25

FRL (Full Reservoir Level, m) = 422.76

Maximum level (Meter) = 425.7

Minimum Draw Down Level (MDDL) = 403.6 m

What will be the level for emergency and principal spillway?

Hi,

Has anyone conducted calibration using the new swat+ model? If so which method did you use? And was it successful?

Hi All,

I have calibrated my SWAT Project using SWAT-CUP successfully. I now want to incorporate baseline and future climate data into calibrated SWAT Model. As the SWAT CUP gives the best parameter ranges after successful calibration how should I incorporate these ranges in Arch SWAT Project?

If I use SWAT-CUP and copy the tmp and pcp files in the calibrated projected folder what should be the format of pcp and tmp files as they are inserted individually in ArcSWAT for each station but collectively found in pcp and tmp files of SWAT-CUP?

Which out of these two methods s accurate and more reliable?

Also when i use the fitted best parameters into my uncalibrated ArcSWAT folder and run with the same data the results are quite different from those in SWAT-CUP calibrated model , why the results are different in this case ?

TIA

Regards.

Hi everyone!

I am researching the impacts of different PET source on runoff. I want to adjust the SWAT source code to read MODIS PET data. Does anyone have instructions on the SWAT source code and the running structure of the source code? Thanks in advance.

Regards.

Any model output depends on its parameters. SWAT is a conceptual model, it contains an enormous number of physical and process-based parameters to capture real-world behaviour. The physical parameters which we can measure directly and the process-based parameters which cannot measure directly and it has to go through calibration or optimization. While optimizing the model, we will select the influential parameters. But, during the screening of influential parameters itself contains huge uncertainty like:

1. Which parameters have to select?

2. How much range has to take for selected parameters?

3. If we select more parameters, complexity and optimization will increase

4. Which method has to adopt for deriving the parameter value like Absolute, Relative or Replace?

Are any optimal methods available to select parameters and its range?