Your area looks good. How many ducks is the yard for?
Ducks get things wet. WET, wet. Then they burrow their beaks down into the mud looking for gooey bits to eat.
It is a different mess than chickens make. Their house gets icky.
I clean my secure night yard once every 2 days - scrape out the damp straw, spray down the pea gravel, then when the gravel is dry, add new straw (in winter, in summer I leave the pea gravel bare).
The duck's house area I have a layer of plastic over the floor, then 3 bags of play sand, then about 8" of hay which I rake around & remove the gross, damp stuff, and cover with straw every 4-5 days. It is usually less disgusting than the night yard, because the ducks like to sleep out there, rather than where it is warm & cozy.
I planted climbing plants that the ducks could nibble along the outside of their coop/run/yard - peas, green beans, calendula, comfrey (okay, so they aren't all climbers) plus there are some wild raspberries that abut their run. It looks much nicer from the outside, and the ducks nibble at the peas & beans & their leaves happily from inside the run. I just toss beans & peas in to them from right outside the yard. It is pretty convenient.
Adding new ducklings is a little easier than adding new chicks.
Most ducks don't seem to be as viscous about pecking order as chickens, though I had a dominant pair that were pretty ruthless. They moved on, not the new duckies.
Once my babies were able to go out for field trips on nice days I used an A-Frame rabbit hutch I have that sits on the ground as their safety zone. I put it right against the ducks' enclosed yard, and the ducklings would spend their days there, where the big ducks could investigate them, but not get to them.
Once they were old enough to spend nights outside I put their safety zone inside the duck house & left everyone in there for a few days.
Once the big ducks stopped running at the hutch & chest bumping it (I think in excitement) I took the hutch out.