I'm going to risk sounding like a total idiot

My obscurus garter loves being in her water pot. I have a tub with lid and a side hole entrance with maybe a cm and a half of water in and she spends a lot of time in it. The very recently acquired Florida blue also spends a lot of time more than the obscurus at the moment in her water tub. So my question is should more provision be given to their love of water by providing a larger water area or even a mini filtered section ? Is it a good idea or does it make the terrarium too humid (this is why I provide pots with lids) ? Is it possible when setting up a naturalistic enclosure to make it part aquatic and still be able to keep it clean ?

In my head I can envisage a lovely large terrarium housing a group of five or so garters with lots of plants and a mini pond. I'm wondering if this is a possibility or just a mad dream.