The clouds (or smoke?) are great! Are they from a symbol set or did you use a different technique?

Realized I didn't have any stains or scum, so added a bit. Really love how this template includes so many different effects options for adjusting the coloring.

Okay, I think I've done my final tweaks for my practice sewers.

I realized that my sewer pipes weren't actually doing anything, so I used end-pipes off of T junctures to allow the graywater they're carrying to be deposited into the sewer canals. Added a few more bridges over the canals because there were a few areas that were inaccessible to maintenance workers. Tightened up the border texture. Moved the water (Effluent 05) in the storm drain canals to a new water sheet to give it a slightly higher transparency. (Not sure if I did that effectively or not.) And I added a bit more drama to the tentacle action in the lower right.

Been plotting out how the waste management system in my major cities will work. From the age of 6 to 14, I grew up without electricity or indoor plumbing, so the ecology of outhouses isn't foreign to me. (What do you do when you fill one up? Dig another hole, and with enough time, the first one will be ready to be re-used again.) We sorted recycling long before curbside recycling existed (not that we had a curb -- we were a mile outside of our tiny town of 3,000 people). Compostables were sorted four ways: veggie peelings and ends for the rabbits in their elevated hutches, coffee grounds went to the worms that broke down the rabbit droppings below the hutches, egg shells were ground up and fed back to the chickens to give them calcium to strengthen their shells, and the rest went to the compost heap. Glass was sorted into separate bins for clear, green, and brown glass. Metals were sorted into separate bins for tin and aluminum. The rest was junk. Plastic wasn't as prevalent then and wasn't recyclable, and had to be taken to the dumps for landfill. So yeah, I've been thinking about the waste management issues for a medieval city. But also: humans and intelligent humanoids are nothing if not resourceful and inventive. In a fantasy world, what sort of burrowing or earth-eating creatures could be put to use to make tunnels easier than medieval humans could? What sort of debris-eating creatures like gelatinous cubes could be used to manage waste? No need in my world to dump untreated sludge back into rivers or oceans!

That’s beautiful!

no, I haven’t figured out how it will all piece together. I think it works well with Sue’s other styles — Marine Dungeons, Forest Trails, Creepy Crypts… But I really have to experiment and see.

I made a few tweaks. Changed most of the effluent to brown except for the portions from the vents (aka storm drains) that's meant to be rainwater. Added a few bunches of leaves from Forest Trail to those ones. Added some bridges for maintenance workers to use to cross canals. Left a bit of green coming from one of the canals -- a mystery for adventurers to solve? I should probably add some slime....