Keep in mind that if there is an animal living in that burrow that animal has learned how to divert large quantities of water away from their living quarters. If they had not learned that they would have been eliminated a very long time ago.
The same would hold true for trying to put gasoline engine exhaust down that hole, and unless you are a mechanic that could cost you a lot of dollars.
Saucers of Ammonia might discourage the bugger as would continuously knocking the hole in.

drowning or gassing.. NEVER works .. its called air transfer and drainage.. things you worked to develop in your soil ...

disturb the whole with a small shovel or just step on it ....... come back tomorrow... if its not reopened.. problem solved ..

if so.. disturb again.. until they begin to understand that you are in charge of this garden.. and not them ...

you are really kinda starting at the extreme of dissuasion.. lol .. whats next.. poisons and a gun?? ... lol ... go simple to start ... you might be surprised how wild animals.. dont like to be disturbed ....

i cant really tell much from your pic... some toads live in holes...

ken