Different Land Use Code in SWAT-Check Land Use Summary Table

[Rajveer]

Hello Everyone, 

I have given the Land use Code URBN for the urban and built up area in the lookup table. 

But when i checked the output from SWAT Check Land Use Summary Table, The code of urban class (URBN) is changed to BERM that is for Bermuda grass. 

But in the Land use report it is showing correct.

Can any one please suggest me why in Land use summary table the Urban class is changed to Bermuda  grass class??? And how it can be corrected??  

[Daniel Fuka]

Bermuda grass is the default crop management practice used for most of the Urban landuses. The landuse is descriptive of the area, while the crop/management practice can change throughout the simulation day to day if you set more complex scenarios. See the OpSchedules[,default] table in SWAT2012.mdb to start the long road of better understanding this realm from the initialization side, though the Theory Manual for SWAT should be open as well, as it is not as complex as it appears from the data initialization side. 

[Rajveer]

Thanks Daniel for the Suggestions. 

So can i continue my analysis with the Land use of Bermuda grass considering as a Urban Land use??

[Daniel Fuka]

No, well.. not if you want to simulate the other Urban processes that SWAT can model. BERM landuse will just simulate the crop model for BERM. The Urban landuses add several additional urban models to the simulation.

See chapter 6.1-6.3 from the SWAT Theory for a better understanding:

https://swat.tamu.edu/media/99192/swat2009-theory.pdf

[Lakhwinder Singh]

Its default, When you give threshold  to land use , soil , slope, its decided at that time. It means smaller class less then specific of some percentage will merge with other class. BERM representing merged class besed on percentage, other class pixel is in such a less amount less then 15, we say cannot countable. So this is actual results.  For more details results see "texinout" files. its just summery. 

[Rajveer]

Thanks Daniel and Lakhwinder, 

The major Land use in my basin is forest, range land and agriculture. The Urban area is very lees having small small patches in different sub basin. 

But i want to simulate the runoff generated from Urban class also?? Is it possible ??

In my TxInOut file Urban class is present 

[Daniel Fuka]

Indeed it is possible, and it sounds as if you are already doing it. You just have to keep track of HRUs to Landuse associations as (say output.hru) will give you the current management practice of the day. 

[NTAKIRUTIMANA Manassé]

Hi Rajveer and SWAT user

I got the same  question as you  Rajveer described below, where mu URBN landuse was change to BERM. When i check with SWAT-checker  URBN is changed to BERM and even in output.hru file , the urban is also changed to BERM for all days, as i'm doing hydrological simulation for my catchment this has high effect on simulated discharge. I have gone through the suggestions that different people gave to you, but no one work for my case.If you can help or someone else, to fix this issue you will save the day for me. 

Thanks in advance to whoever will help

[Jim Almendinger]

This issue has been described and explained many times before.  It is not a problem -- it is simply that SWAT models the pervious surfaces in urban settings as bermuda grass (BERM) and so explicitly uses that as its "crop" there.  This is expected behavior of SWAT, and not a mistake to be corrected.  

-- Jim

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James E. Almendinger, PhD Director, St. Croix Watershed Research Station 16910 152nd St N, Marine on St. Croix, MN  55047

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