As a SWAT modeller and programmer, it’s very natural that I want to go deep into the SWAT source codes whenever questions come out. And again, it would be better to run SWAT live and look into values of all the variables to help trouble shooting. To do this, there are two options: commercial Intel fortran compiler and free gfortran. It’s hard to say which one is better. I chose gfortran for its price, freedom, cross-platform and multi-language compiling ability. For some reason, not all SWAT source code files follow the same standard. Compiling SWAT with gfortran is not as easy as Intel fortran. After some research, it comes out the best way to compile SWAT with gfortran. All the necessary steps are documented in one single user guide document with the hope it would be helpful.
All the efforts was recorded in following posts. And here are some important links.
Compile and Debug SWAT with GFortran and Eclipse (Windows version)
https://docs.google.com/document/d/16Do2U1_v4mZZBOV0hmcs6Gh1UvAUAXOMidpB-SE203A/edit?usp=sharing
Makefile
https://drive.google.com/file/d/0B16YhFB_9MejSG15ai0zYS1fMkU/edit?usp=sharing
Makefile Generator
https://drive.google.com/file/d/0B16YhFB_9MejZkxiakdLTHhMVlU/edit?usp=sharing
Posts
February 28, 2014 Single Document about Compiling and Debugging SWAT with GFortran and Eclipse
February 18, 2014 Makefile Updated – 1) No Need to Modify main.f any more; 2) A Single Makefile; 3) 64-bit Build
February 2, 2014 SWAT Makefile Updated – Ignore Underflow
January 28, 2014 MinGW Installation Guide for SWAT Debugging
January 28, 2014 Debug SWAT in Eclipse – Utilize Makefile
January 24, 2014 SWAT Makefile Updated – Stop running when overflow happens
January 23, 2014 Makefile – Compile SWAT using gfortran without modification
January 5, 2014 Compile and Run SWAT with Photran + MinGW – the easiest way to remove mathematical errors from SWAT
Michael Yu 
Hello,
(Sorry for posting this again, but i felt this was a more appropriate place to do so).
I was installing the MinGW-w64 from (http://sourceforge.net/projects/mingwbuilds/files/mingwbuildsinstall/mingwbuildsinstall.exe/download) and my installation always showed the error “ERROR res” and yet the installation completed.
Then there is no “C:\Program Files(x86)\mingwbuilds\x324.8.1win32dwarfrev5\mingw32\bin” folder – basically there is no “mingw32″ folder.
I hope you can help me out with this.
Thanks a lot for this blog – i hope to get a lot of use out of this!
Hi Soham,
Good to hear from you.
To be clear, which installation file did you use exactely as there are different options there? We could go from there.
Cheers
Michael
Hi Michael,
Thanks for the prompt response!
As far as i kept track, i first downloaded using “Auto-select”, and later tried all the other mirrors (if that’s what you mean by different options). Perhaps another thing i should mention is that i am currently in an educational institution in India, which uses proxy servers for internet. After each download, unless i used ‘no proxy’, i always got an error which didn’t let the installation start. Maybe that means something?
Thanks!
Soham
Hi Soham,
Have you try this link http://sourceforge.net/projects/mingwbuilds/files/mingw-builds-install/mingw-builds-install.exe/download? It will direct to you to the file directly. I’m in Canada and don’t know if the proxy would have any impact on the download. Please let me know if it works.
Thanks
Michael
hello sir..,
I have followed the guide of “Compile and Debug SWAT with gfortran and Eclipse” on the link https://docs.google.com/document/d/16Do2U1_v4mZZBOV0hmcs6Gh1UvAUAXOMidpB-SE203A/edit?usp=sharing, but i found some errors specially in file “readbsn.f” line 698. could you explain please how to solve my problem.
Hi friend,
Please see my another post https://zhiqiangyu.wordpress.com/2014/07/16/swat-changes-from-rev-622-to-rev-627/. The variable defined in basin.bsn is a real value but the variable in the program is using integer. For some reason, gfortan compiled program has problem when reading this but Intel Fortran don’t. Easy way to solve this is to change the prf value as an integer in bsn file.
Regards
Zhiqiang
Dear Zhiqiangyu,
I received an error when trying to compile the SWAT2012 rev 637 source code. I am compiling from command line using mingw32-make and gfortran. The error message is below. I am not sure, but it sounds like the problem has something to do with the last parenthesis not being interpreted on line 10 of the ndenit.f file.
Error message:
ndenit.f:10.72:
wdn = sol_no3(k,j) * (1. – Exp(-cdn(j) * cdg * vof * sol_cbn(k,j))
1
Error: Expected a right parenthesis in expression at (1)
Makefile: 342: recipe for target ‘debug32/ndenit.o’ failed
mingw32-make: *** [debug32/ndenit.o] Error 1
Thank you,
Steve
Hi Steve,
Yes. It may exceed the max length of line. Simply remove some space in the line make it shorter would be good to go.
Thanks
Zhiqiang
Zhiqiang,
Thank you for your reply. I think I was able to resolve this single error by adding flag ${LONGFIX} to the line in the Makefile where ndedit.f is compiled (near line 341). Unfortunately, when I tried compiling again I received a cascade of errors that I was not able to resolve. I am not sure why I am receiving so many errors given how straightfoward your instructions (with Makefile) were. The instructions I followed are via the link below. Do you know if the current SWAT release (rev 637) works with these instructions and Makefile? I am using the MinGW and MSYS method in your instructions.
Instructions I followed:
https://docs.google.com/document/d/16Do2U1_v4mZZBOV0hmcs6Gh1UvAUAXOMidpB-SE203A/edit?pli=1#heading=h.vai8uo4ma0x2
Thank you,
Steve
Hi Steve,
I don’t think rev 637 would have big difference apart from previous versions. It would be helpful if you could send the error messages. You may also try the methods I have suggested in last reply.
Thanks
Zhiqiang
Zhiqiang,
I tried compiling SWAT using your Makefile after removing Strawberry Perl (I think there were some problems with multiple shared files). The debug32 version compiled okay after I added ${LONGFIX} to the Makefile lines to compile ndenit.f, nminrl.f, and readbsn.f. However, the rel32 version (which is faster and what I want) failed to compile. When I tried compiling, I received the output below (stdout, stderr) and got two pop up windows “There is no disk in the drive. Please insert a disk into drive \Device\Harddisk5\DR5” ??
stdout and stderr:
mkdir -p rel32
gfortran -m32 -c -fmessage-length=0 -funderscoring -fbacktrace -ffpe-trap=invalid,zero,overflow -O3 -ffixed-line-length-132 ndenit.f -o rel32/ndenit.o -I rel32
ndenit.f:4.9:
use parm
1
Fatal Error: Cannot read module file ‘parm.mod’ opened at (1), because it was created by a different version of GNU Fortran
Makefile:2187: recipe for target ‘rel32/ndenit.o’ failed
mingw32-make: *** [rel32/ndenit.o] Error 1
Do you think there is a problem with the “parm.mod” module? I feel like I am getting close here.
Thanks,
Steve
Hi Steve,
Good to hear you have some progresses.
I have seen this error before. Try to delete parm.mod again and re-do the compilation.
Thanks
Zhiqiang
Hi Zhiqiang,
That was a good suggestion. I deleted the “rel32” folder and tried recompiling. The parm.mod problem seemed to go away, but then every time gfortan was invoked in a compile statement, an “insert disk into drive” error window popped up. I didn’t want to close 300 windows, so I forced quit the make process. The problem may be that I’m working over a Remote Desktop connection, and so maybe one of my system drives is mapped? Not sure. I’ll try this again next time I’m in the office and report back.
Thanks,
Steve
Zhiqiang,
Okay, I tried again to compile SWAT using the Makefile with MinGW make (mingw32-make). Although I nolonger receive compile errors, I am prevented from compiling because I get a pop-up window instructing me to insert a disk into my CD drive every time gfortran.exe or f951.exe are called during the make process. This window has to be closed before the compile process can continue, therefore I am unable to compile. Here are the error messages:
Text in pop-up window opened from call to gfortran.exe:
gfortran.exe – No Disk
There is no disk in the drive. Please insert a disk into drive \Device\Harddisk5\DR5
Text in pop-up window opened from call to f951.exe:
f951.exe – No Disk
There is no disk in the drive. Please insert a disk into drive \Device\Harddisk5\DR5
What a strange error. Do you know of a workaround?
Thanks,
Steve
Hi Steve,
It’s quite interesting. Where do you put your source files? Have you tried to run the gfortran in command window? You could write a simple Fortran program and compile it with gfortran to see what will happen. If you still get the same error message, it’s something related to the gfortran. If not, it should be related to the location of the source files.
Thanks
Zhiqiang
Hi Zhiqiang,
I am running gfortran from a command window. I just compiled Hello World successfully. My source code is located in folder: D:\Steven_Jepsen\Hydrologic_models\SWAT\source_code_SWAT2012\rev637_source
I reinstalled MGWIN this morning. I noticed three errors in the installation process relating to a gcc folder. Sorry, I did not write the errors down (I knew I should have, but still didn’t).
I am going to shelve this (at least for a while) until I hear of a fix. Compiling SWAT is not a necessity at the present time.
Thanks,
Steve
Dear sir
I have found difficulty in downloading MinGW-w64
I am in Nepal and i have used both the links above, the installation however is complete but
mingw32 is missing in
C:\Program Files (x86)\mingw-builds\x32-4.8.1-win32-dwarf-rev5\.
My aim of compiling the swat codes is to print snowpack and sublimation which it computes
but doesnot print ( it has commented the codes and wbl,out isnot printed)
Thanks for your great blog.
Regards
Shiva
Research assistant
Hi Shiva,
Not sure what caused the problem. May be try to use other options, like the Rtools?
Thanks
Zhiqiang
Shiva,
I am not sure if this is any help, but I have obtained SWE output by enabling print of the “SNO_HRU” variable in the HRU output. Also, I recall going through this HRU output and noticing that snow sublimation appeared to equal ET when snowcover is present. But perhaps this does not hold for all conditions (?), and would probably be good to doublecheck.
Steve
Dear zhiqiangyu
I am new to this compiling. I dont really have a good knowledge on it.
Actually i faced the same problem Soham Adla faced at the start of this thread.
However,i have installed Rtools and followed as mentioned in the your doc file in the blog(comments).
I tried it but it didnot work for me.
I couldnot download C:\Program Files (x86)\mingw-builds\x32-4.8.1-win32-dwarf-rev5 successfully. Thats the only thing i missed in your doc.
Dear Steve,
I am not sure where you are getting this output.
If you are talking about Sno_mm in the output.hru, thats not the snowpack and also in the documentation it
says not accumulated or something like that.
Regarding sublimation , can you please clarify how you noticed snow sublimation is equal to ET.
I dont know how it is possible cause i think there is always ET from soil and plants added to ET that SWAT prints.
Regards
Shiva
Hi Shiva,
sno_hru in the hru output is definitely the accumulated water equivalent of the snowpack. I found this by examining precip, snowfall, and sno_hru in the hru output. That is the only way I can make sense of what the output really contains. I could not understand the description of sno_hru clearly enough in the I/O documentation (the document has some rough spots).
Regarding ET, you are probably correct. I noticed that for one of my HRUs with bare land conditions, ET was equal to snow sublimation (again I could tell this from the hru output). However, in general plant transpiration would likely change this.
This equation should work to solve for snow sublimation from the HRU output:
sublimation = delta(sno_hru) – snowfall + snomelt
Steve
Hi Guys,
Nice discussion here.
For me, sno_hru is the SWE of each HRU.
Sublimation is part of ET. It will be less than or equal to ET depending on conditions. For winter, the plan is not growing, the plant part will be zero, which would lead to ET = Sublimation.
Sublimation is calculated with other equations. The it’s could be check using the equation given by Steve.
Thanks
Zhiqiang
Dear Michael
I amnot being able to instal the compiler properly..
I couldnot download 32-4.8.1-2win32-dwarf-rev5 .
Is there anyother way, i could sort this issues.
2.in my swat model, when i used the outputs from output.sub
and calculated effective yield at the basin outlet by sumproducting the yield and sub basin area and dividing it with total area, and the flow at the outlet from output.rch ,there is a discrepancy.
Waterbalance has been a key issue in my swat model.
Can you guide me the way to check waterbalance at HRU and subbasin level and correct this issue?
Thanks for your kind attention
Regards
Shiva
Hi Shiva,
What happened when you were trying to download MinGW-w64? I’m not quite sure why it’s like that. Have you try RTools?
For water balance, you calculation didn’t consider the loss in the channel routing. It’s normal they are different. I’m not sure why you want to check the water balance as it’s maintained very well in different level. I don’t think we need to to check that. Do you have any special concern?
Thanks
Zhiqiang
Hi Michael
I have tried to compile swat code following your instruction but I have faced some problems.
First, why in problem tab has type of error or warning in “C/C++ problem”.
Second, I haven’t seen the “Fortran Local Application” in Run configurations.
Third, I copied swat_debug32.exe and ran in txtinout of SWAT project I got an error: “Program received signal 8 (sigfpe) floating-point exception.”
I installed jre-8u111-windows-x64:
eclipse-parallel-neon-R-win32-x86_64: C:\eclipse
Rtools31: C:\Rtools
mingw-w64-install: C:\Program Files (x86)\mingw-w64\i686-6.2.0-win32-dwarf-rt_v5-rev1; C:\Program Files (x86)\mingw-builds\i686-4.9.1-release-win32-dwarf-rt_v3-rev2
mingw-get-setup: C:\MinGW\bin
Can you please tell me ways to solve these problems?
Thank you,
Tu Le.
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
Hi Ameya,
The water balance of snow pack should be checked separately with new snow as gain and snow melt and sublimation as loss. These three are in the summary result but the snow accumulation is not. You need that number to check the balance.
The runoff is quite low and groundwater water contributes a lot more. Consider to check the soil parameters and CN numbers.
Best,
Michael
Thank you michael for your reply.
My CN number is 17 which is low if i increase the cn and other soil parameters my NSE and R2 decreases.
So should i just leave the model like this. Also while checking water balance
is this formula correct.
Water Yield=Qsuf + Qgw + Qlat- Qloss
Precipitation=AET+ water yield+ Deep AQ recharge
Hi Ameya,
For me, the CN is too low. Reviewers will have questions.
I think water yield should equal to Qsurf + Qgw + Qlat. Precipitation should also consider the snow accumulation and the change of soil moisture.
I don’t think you need to check the water balance. The SWAT model has check all the water balances.
Best,
Michael
With this value my observed and simulated discharge is okay but if i increase the cn value and soil parameters the error parameters increases. I just want to check the water balance. Can you please tell me the process to check it.
Thank you micheal for your advice. My sub basin consists of mostly forest area. This maybe one of the reason for low CN value. My CN value are in the range of 30 but swat check shows average cn as 17. Is there any reason why is it that so.
Thank you micheal for your advice. My sub basin consists of mostly forest area. This maybe one of the reason for low CN value. My CN value are in the range of 30 but swat check shows average cn as 17. Is there any reason why is it that so.
That CN is the average of actual CN used in simulation.
Thank you very much for replying me micheal. Actually i tried replacing all my CN value with 77. But when i went to swat check and check the average value i got just 31 as average CN value. Why is that so?
Hi Zhiqiangyu
I am trying to compile SWAT source code rev670 from command line after following your tutorial and I am having the following error:
Error: ‘atri’ of module ‘parm’, imported at (1), is also the name of the current program unit
Makefile:63: recipe for target ‘debug32/atri.o’ failed
mingw32-make: *** [debug32/atri.o] Error 1
Being not familiar with Fortarn, I thought it is because param is duplicated. So I tried to comment it in the modparm.f which seems to work but later on other errors appear as follow:
Warning: Extension: Unary operator following arithmetic operator (use parentheses) at (1)
gfortran -m32 -c -fmessage-length=0 -funderscoring -fbacktrace -ffpe-trap=invalid,zero,overflow -O0 -g -fbounds-check -Wextra bmp_wet_pond.f -o debug32/bmp_wet_pond.o -I debug32
bmp_wet_pond.f:241:8:
& 0.043,0.053,0.064,0.077,0.092,0.11,0.134,0.166,0.212,0.287,0.384,
1
Error: Syntax error in array constructor at (1)
bmp_wet_pond.f:282:61:
call wpnd_depth(hvol,wdth,wtp_sdslope(sb),alpha,hdep)
1
Error: Symbol ‘hdep’ at (1) has no IMPLICIT type
bmp_wet_pond.f:270:16:
if (ia>cumrain(ii)) then
1
Error: Function ‘cumrain’ at (1) has no IMPLICIT type
bmp_wet_pond.f:271:17:
ia = cumrain(ii)
1
Error: Function ‘cumrain’ at (1) has no IMPLICIT type
bmp_wet_pond.f:274:48:
fa(ii) = ss * (cumrain(ii) – ia) / (cumrain(ii) – ia + ss)
1
Error: Function ‘cumrain’ at (1) has no IMPLICIT type
make: *** [debug32/bmp_wet_pond.o] Error 1
I would be grateful if you can support on this.
Thanks in advance.