63 thoughts on “SWAT

  1. Hello Dear,

    I face these problems while working on SWAT2012.

    After I run the SWAT, the result for sediment yield is zero i.e. there is no sediment yield.
    what could be the problem and how can I solve this?
    I know my project area is sediment prone area and there is prevailing sediment problem.

    I have very short time for my project please help me.

    Thank you in advance for any help you can provide.

    Best regards,

    • Hi Lemma,

      You may need to check the overland and channel sediment. As you know MUSLE is used to calculate the erosion, any zero factor would lead to zero sediment. Without the project files, I couldn’t tell which parameters have problem.

      I would suggest focus on one HRU or subbasin. And look into all parameters and outputs.

      Good Luck

      • Hi zhiqiangyu,

        I’m a graduate student, new SWAT user. I have a question for SWAT calibration. My study area include two hydrological stations in the south central China. In the calibration, the downstream hydrological station has worse results,R^2=0.45 and NSE=-0.15, but the upstream hydrological station has better results, R^2=0.72 and NSE=0.72. I don’t know what happened, and how should I check my model? The result of SWAT check as following.

        Groundwater ratio may be low
        Lateral flow is greater than groundwater flow, may indicate a problem
        Water yield may be excessive
        Surface runoff may be excessive


  2. Hi Michael Yu,

    My lack of experience in using SWAT leads me to ask every simple questions you can imagine. But still I have to ask because I want to learn. And I hope you will consider my questions.

    The sediment problem is solved and thank you for your help. Now I am calibrating SWAT. But the model under estimated the flow. there is low surface flow and high lateral flow. I got the warnings below. I tried to Increase the CN (in .mgt), Sol_AWC(in .sol) and ESCO(in .bsn) but still no significant change/improvement on the ratio.
    Surface runoff ratio may be low (< 0.2)
    Groundwater ratio may be low
    Lateral flow is greater than groundwater flow, may indicate a problem
    Water yield may be excessive
    Surface runoff may be too low

    The significant under prediction during calibration is for baseflow. The quick flow is more or less sufficiently predicted.

    Do you have suggestion)

    Thank you.


  3. Hi Michael Yu,

    My Catchment is located in Nepal, South of Kathmandu. I have been assessing the problem regarding the water balance. But, the problem related to lateral flow persists. The lateral flow is very big even much more bigger than surface runoff about six(6) times bigger. I cannot find the solution how to reduce it. I tried to increase the percolation to shallow aquifer and deep percolation as well as increasing the surface runoff but it is still too much. Do you have any idea)

    Thank you.


    • Hi Lemma,

      Heard some news about the earthquake in Nepal. Hope you are doing good.

      To find solution, it’s better to look into all the model results including all parts of the water balance. What about you send me the project for me to have a look? If it’s not possible, you could also send me the model outputs.


      • Hi Michael,

        Thank you. by the way I am not from Nepal. But, I have friends from Nepal. I have heard the news about the earthquake and it is really heartbreaking and disturbing. I hope they will recover soon. I am from Ethiopia Studying MSc. in Norway. Below I attached you my project for you to have a look at it. My land use and soil data is not of good quality. I am using online available data any way because I couldn’t get a better data. To include some description; I have only one weather station which records precipitation the temperature data was transferred from the station outside the catchment Many thanks for your. You have been helping me a lot.

        Best regards, Lemma​ MY_SWAT PROJECT.rar ​

      • Hi Lemma,

        It’s good you are not there.

        I’m not sure how you attached the file. I just see the file name but not the file. I don’t think you could actually upload a file in the comment system. If you like, you could send the file through email (hawklorry@gmail.com). I would be happy to look into that for you.


  4. Dear Michael

    I am currently working in hydrological model of kabul, afghanistan.
    My problem is water balance.

    To brief, precipitation occcurs in winter and is stored as snow( it is not printed by SWAT)
    which melts during summer and high flow is observed then.more than 75% of the flow is due to snow melt.

    At the start of my simulation, the outflow was 5 times that of observed.
    I had to increase ET to incur water losses. I put solawc to near 1 and esco to near zero but didnot help me alot so i asssigned snocovmax to 500. only then i could do my calibration.

    The problem with water balance is that.
    water yield is not equal to the sum of lateral flow, ground water and surface in output.sub on monthly basis but when compared at yearly level, only small deviation observed

    The water yield however from output.std doesnot match with from output.rch.
    the yield shown in output.std is only half of that shown in output.rch.


    • Hi Shiva,

      I would think SWAT has tried its best to keep the water balance. You may also want to look into the HRU outputs. Maybe you could share the result file to look into further. If a bug is there, we should report to SWAT team.

      And Sol_AWC close to 1 is too high for me. You may need look into other aspects to lower down the flow.


  5. Dear Michael

    Is it not amazing why SWAT wont print Snowpack and sublimation?
    How would one check water balance in a snowfed catchment?

    I want to share my result files.
    How may i do that


  6. Dear Michael

    The only way could lower flow so far as i know

    1. ET for which i had to increase sol_awc ,decrease esco
    2. I have to increase snocovmx which increased ET as sublimation

    I used hargreaves as method of ET
    My ppt 512 mm
    Yield – 200 mm
    area – 67500 km2

  7. Hello,

    Good day to you.

    Please, I am using the SWAT model to simulate stream flow in a catchment around Lake Victoria in Uganda. But, I have encountered some difficulties in inputing the soil map. The user soil names appearing on the program do not match with the soil names on the attribute table of my soil map. I downloaded the soil map from FAO soils website. Please, can you help me to rectify what to do?

    Thank you!


  8. Hi Michael,

    I am trying to model a catchment in south china with rubber trees dominated landuse. I am getting too high lateral flow and excessive water yield. I have been changing all groundwater parameters but I didn’t succeed to fix the problem. Do you have any comment on this? I know rubber trees are acting as water pumps but I don’t know how to implement this fact in SWAT.


    • Hi Ned,

      Try to check the parameter of the rubber tree in crop database. Also check the ET and water uptake. See if there are any stress on temperature, nitrogen and phosphorus.


  9. from SWAT output.std :

    So what can I do know about it?


      • Hey Michael,

        I checked the HRU output and apparently my forest landuse (FRSE and FRST) is facing excessive nitrogen stress days. However, since this is a forest, I cannot apply fertilizers. Do have any suggestions?

        Best regards

  10. Hello!

    I have a problem with P_STRS modeling. This value always = 0 even without any fertilizers. I don’t understand fortan, but for me “!”-character looks strange in npup.f:
    uapd = up2 – plantp(j)
    ! uapd = Min(4. * pltpfr(3,icrop) * bioday, uapd)
    uapd = 1.5 * uapd !! luxury p uptake

    I checked 528_code and didn’t find “!”. Is this difference important?

    Thank you!

    • Hi Valeriy,

      Sorry to respond late. With latest ver637 code, that line commented with !. It should be done on purpose. If P_STRS is always 0, you should consider to lower the available phosphorus.


  11. Helloo zhiqiangyu

    I am currently working in hydrological model of Land use land cover change

    actually prepared the required format for ARcSWAT 2009. But faced the problem with Input files of Weather Genereator parameters.. the display says that No data value are given for one or more parameters. IN,mWriteInputefiles.Ggn.

    Would you give me a=help on this



    • Hi Tesfahun,

      I haven’t been using ArcSWAT 2009 in recent years. For the error, it seems some data is missing from your input data. As it didn’t give which column is missing, it’s hard to tell. I would suggest to look into your weather data and make sure everything is in the right format. And then redo the process.


  12. Hello Zhiqiangyu,

    When I checked “Create HRU Feature Class”, the model stuck and shows a error message. If I unchecked it, model goes finely. But I need HRU feature map for my analysis. Few information about my model, area = 308188.00 (hec), no of subbasin: 65, and no of HRU: 2365. I am usig arcGIS 10.2.

    Do you know is there any solution of it.



      • Hello Zhiqiang,

        Thank you for reply. I attach here the error message I found. Error description is in German language. So, I translate that.

        Regards Jakirullah

  13. Hello all

    I have used swat checker to identify potential problems with my simulations. I have a five year period of warm-up but in the hydrology tab, i get the message that “Water yield may be excessive” and ” Surface runoff may be excessive”. How do i go about this? I am working at a 13 km2 forested watershed.

    I have noticed that others encountered problem with only low surface runoff which was easily rectified.

    Any help would be deeply appreciated. Thanks

  14. Hello Zhiqiang,

    I am currently working in hydrological model and sediment transport in a Peruvian watershed, I want to know if it is possible install the SWAT 10.3 in the ArcMap 10.4. And if it is possible, how can I do it? Could you give me a suggestion ?

    Thank you very much and I really appreciate your help


  15. Hi sir,
    Actually i am trying to run the swat simulation after the input tables got created. It is giving a error message-forrt1:erroe(73) : floating divide by zero. So, please give me some solution for this problem as fast as possible.

  16. Dear Michael,

    I am a new SWAT user and currently a researcher at Indian institute of Technology, Bombay. I am facing Some problems with Model, I believe you can help me with following problem.

    I want to add soil data into the model. The soil map is at village level. But when I load the shapefile it gives the following error. I am also attaching the screenshots.

    Unexpected Program Error Error Call Stack Sequence
    CreateOutputFilesDbase LUGridShp.vb Line: 3362
    Error Number
    Value does not fall within the expected range

    Parth Gupta

    • Dear Zhiqiang

      I am a new SWAT user and currently a researcher at Indian institute of Technology, Bombay. I am facing Some problems with Model, I believe you can help me with following problem.

      I want to add soil data into the model. The soil map is at village level. But when I load the shapefile it gives the following error. I am also attaching the screenshots.

      Unexpected Program Error Error Call Stack Sequence
      CreateOutputFilesDbase LUGridShp.vb Line: 3362
      Error Number
      Value does not fall within the expected range

      Asrat Shanka

  17. Hi Michael,

    I am using SWAT for hydrological modelling & sediment in highland agricultural area in malaysia.
    Model ran succesfully but the water yield too low,
    Total area is 179km2, 1 weather stn & 6 rainfall stns.
    I tried many things:
    – change CN, sol_awc, gw parameters
    – i did swat cup but best nse is still -0.3
    – it has been going on for almost 8 mths now

    Is it because of no weather stn & rainfall stn insufficient??


    • HI Azwin,

      0.09 is not low to me. Check the water balance using the SWAT_Check. It’s either ET or percolation. For your NSE, compare your flow data with precipitation data and see if the response is reasonable. Use reasonable part for your calibration.

      Hope this helps.


  18. Dear Michael,
    I am facing some problems regarding my weather data. I have temperature, precipitation, solar radiation, wind speed and humidity data. Only my temperature and precipitation data work, for the rest of the data I get an error like this “forrtl: severe: input conversion error, unit 137, file F:\Masterarbeit\Projects\Project_26_11_copy\Scenarios\Default\TxtInOut\slr.slr” when running SWAT.
    Interestingly, if I only use data from just one station (any station) instead of data from multiple stations, I can also include solar radiation, wind speed and humidity data without any error.
    I couldn’t find any useful information on this error online so far, do you have an idea?
    It would be great if you can help me out, I would really appreciate it.
    All the best,

    • Hi Johannes,

      It’s usually caused by the wrong format in the climate file. Try to open slr.slr in a text editor and check if all the lines are in same width. If not, change them to proper format. You could also send me the file (hawklorry@gmail.com).


    • Hi Johannes,

      To add to previous reply, the empty value -99 should be format as -0099.00 rather than -0099.000. If you see -0099.000, replace them to -0099.00.


      • Hi Michael,
        you were right. I changed the format from -0099.000 to -00.99.00 and now it works! Thank you very much for your help, that’s really nice of you. Do you have an idea where this error comes from and how to avoid it?

  19. Hi Michael,

    I am new to SWAT modelling.

    I got the ArcSWAT set up files from Client which is in SWAT2012.exe Revision 591 is packaged with ArcSWAT 2012.10_1.8 version files.
    But I have the only free version (QSWAT+QGIS) to use here and latest ArcGIS 10.5 also.

    My query is as follows:

    1. is it possible to open the relevant files or equivalent ones in QSWAT/QGIS to get the equivalent model set up in QSWAT? I tried to get up to the delineation of the watershed using their DEM and river network. But not possible to use the outlet points. Then stuck up at HRU stage. Not able to use the land use and soil files from their model set up files.
    2. Is there ArcSWAT version compatible for 10.5 ArcGIS version available? if not when this is going to be released?
    3. If I install 10.4 ArcGIS and corresponding ArcSWAT version, can I able to open the above set up (2012, 10.1 version)? If so, I can look for 10.4 license file with the client.
    4. Is there any conversion tool available to convert the ArcSWAT set up into QSWAT version?

    Thanks in advance,

    • Hi Suresh,

      Thanks for reaching out. For your query:

      1. I think the answer is yes. I’d suggest you to contact the author of QSWAT Chris George .
      2. It seems there is no ArcSWAT for ArcGIS 10.5. The SWAT team will shift to QSWAT in the future as it’s fee and easier to maintain.
      3. I’d think so. They may upgrade your database to a latest version.
      4. I don’t think so. Please contact the author of QSWAT Chris George .


  20. Hi Micheal,
    I am calibrating a basin in Nepal. I wanted to check my water balance considering snowfall. How would I do that in Swat. Also swat check shows my surface run off is low and water yield may be excessive. I have tried solving this problem but while i tried solving this issue my Nash-Sutcliffe and R2 decreases. What should i do with this issue.

    Precipitation 525.4mm
    Snow fall 114.87mm
    Snow melt 54.93mm
    Sublimation 27.84mm
    Surface Run off 2.63mm
    Lateral Soil 150.79mm
    Ground Water (Shallow AQ) 180.78mm
    REVAP 23.87mm
    Deep AQ recharge 96.09m
    Total AQ recharge 300.93mm
    Total water yield 334.20mm
    Percolation out of soil 300.93mm
    Actual evapotranspiration 101.3mm
    Potential evapotranspiration 265.2mm
    Transmission losses 0mm

  21. hi iam ashenafi nigusie from Ethiopia
    I use swat for investigation of LULC Change impact of river flow using Swat model, but when run simulation for swat model ,the set up swat run is not say database/schema_full.ini file doesn’t exist how i can solve it.

  22. Hi,
    I’m a graduate student. I’m trying to compile SWAT-670 source code in Linux base. But, I am getting fatal error message as “Fatal Error: Can’t open module file ‘parm.mod’ for reading at (1): No such file or directory
    compilation terminated.”
    Do I have basic error?, have anyone guide me on this?

  23. Hi Sir,

    I’m currently a graduate student and a new QSWAT user. I have encountered a problem with creating my HRUs. I got a message saying “There is no crop or soil data for the upslape of channel 346 in Subbasin 1 (and perhaps others)”. Could you kindly assist me?

  24. Hi Lemma Tufa,Am glad to see you here on this group.may you send me your address for communication regarding norway .
    Alemayehu from Ethiopia

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