Inputting a Lake as a Reservoir in SWAT+

[Paige B]

Hi Everyone, 

I am trying to add a lake to my watershed model in SWAT+ editor by having it as a reservoir. I was told that this is the best way to include a lake. However, I have tried two different ways receiving errors for both.

The following error occurs when I have the lake as a reservoir with no outlet and have the reservoir as the outlet:

Could not load SWAT+ Check because the table "basin_wb_aa" does not exist in your output database. Re-run your model and check all yearly and average annual files under the print options, and keep the analyze output box checked.

RE-CONFIGURE MODEL RUN

This error occurs when the reservoir has a channel as the outlet:

forrtl: error (65): floating invalid Image PC Routine Line Source rev61.0.1_64debug 00007FF648936732 RES_INITIAL 35 res_initial.f90 rev61.0.1_64debug 00007FF649AB4063 PROC_RES 27 proc_res.f90 rev61.0.1_64debug 00007FF64943AC64 MAIN__ 100 main.f90 rev61.0.1_64debug 00007FF649BDB0EB Unknown Unknown Unknown rev61.0.1_64debug 00007FF649BDB819 Unknown Unknown Unknown rev61.0.1_64debug 00007FF649BDB732 Unknown Unknown Unknown rev61.0.1_64debug 00007FF649BDB5EE Unknown Unknown Unknown rev61.0.1_64debug 00007FF649BDB88E Unknown Unknown Unknown KERNEL32.DLL 00007FFB4C43E8D7 Unknown Unknown Unknown ntdll.dll 00007FFB4E04C53C Unknown Unknown Unknown

The water entering this lake ends up leaving the watershed area that I am modeling. I am interested in the lake nutrient levels and nutrients reaching the lake through the input channels. If there are any solutions or suggesting for inputting a lake, the help would be greatly appreciated!

[Chris George]

I doubt the errors you report are directly caused by adding the lake,
but I suspect you may not be adding the lake correctly.

You add the lake as a shapefile, and QSWAT+ should do the rest. You can
mark the lake as a reservoir by including an attribute called RES and
setting it to 1, but this is the default if there is no RES field.
QSWAT+ will calculate where a channel exits the reservoir shape and mark
the reservoir point there: you do not need to add any such point yourself.

Chris

On 2/2/2026 10:06 PM, Paige B wrote:
> Hi Everyone,  I am trying to add a lake to my watershed model in SWAT+
> editor by having it as a reservoir. I was told that this is the best way
> to include a lake. However, I have tried two different ways receiving
> errors for both. The following

> ZjQcmQRYFpfptBannerStart
> This Message Is From an External Sender
> This message came from outside your organization.
> ZjQcmQRYFpfptBannerEnd

> Hi Everyone,
>
> I am trying to add a lake to my watershed model in SWAT+ editor by
> having it as a reservoir. I was told that this is the best way to
> include a lake. However, I have tried two different ways receiving
> errors for both.
>

> *The following error occurs when I have the lake as a reservoir with no
> outlet and have the reservoir as the outlet:*

>
> Could not load SWAT+ Check because the table "basin_wb_aa" does not
> exist in your output database. Re-run your model and check all yearly
> and average annual files under the print options, and keep the analyze
> output box checked.

> RE-CONFIGURE MODEL RUN <#/run>
>
> *This error occurs when the reservoir has a channel as the outlet:*

>
> forrtl: error (65): floating invalid Image PC Routine Line Source
> rev61.0.1_64debug 00007FF648936732 RES_INITIAL 35 res_initial.f90
> rev61.0.1_64debug 00007FF649AB4063 PROC_RES 27 proc_res.f90
> rev61.0.1_64debug 00007FF64943AC64 MAIN__ 100 main.f90 rev61.0.1_64debug
> 00007FF649BDB0EB Unknown Unknown Unknown rev61.0.1_64debug
> 00007FF649BDB819 Unknown Unknown Unknown rev61.0.1_64debug
> 00007FF649BDB732 Unknown Unknown Unknown rev61.0.1_64debug
> 00007FF649BDB5EE Unknown Unknown Unknown rev61.0.1_64debug
> 00007FF649BDB88E Unknown Unknown Unknown KERNEL32.DLL 00007FFB4C43E8D7
> Unknown Unknown Unknown ntdll.dll 00007FFB4E04C53C Unknown Unknown Unknown
>
> The water entering this lake ends up leaving the watershed area that I
> am modeling. I am interested in the lake nutrient levels and nutrients
> reaching the lake through the input channels. If there are any solutions
> or suggesting for inputting a lake, the help would be greatly appreciated!
>

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