Wasn’t sure where to ask this question so I plunked it here. One of my ponds is used by my daughters as a swimming area. I have a small dock but would also like to have a clean and clear area to wade in from shore. The bottom is relatively clean. There’s a little silt over shale and clay. Firm bottom. I’ve thought about dumping some gravel maybe or sand. But also wondered if there are any other options? In my head it seems like there should be some kind of sinking mat that could be used for this purpose. I’d appreciate any suggestions. And I’m talking a very small area. Call it 10 yards wide or so and maybe extending 10 feet into the pond.

It is darn near impossible to keep a spot like that clean.
My pond has been full of water for a little over a year, and is getting ~9hrs aeration nightly.
I raked this pile of yech off of the gravel boat ramp yesterday.
It's a lovely mix of sago, FA, and tree leaves, with lots of tadpoles, baby crayfish, dragonfly nymphs, minnows, and other assorted underwater creatures.
Smells worse than a hog farmer's boot. There's a lot more stuff there than it seems. The heap is about knee-high, 3'x6'.

There is a "sinking mat" made for this purpose - I have been considering it for my pond too: https://www.lakemat.com/muckmat-pro/

When our pond was built, we had about 13T of 3/8" pea gravel made into a small beach. Its probably 40' wide and extends into the pond to a depth of about 3.5'. Doesn't take much pea gravel (at least, when everything was new and dry) to get enough of a surface to walk on without being in squishy clay.

A small area for a beach is manageable enough.
First, do like Augie and rake the big stuff that blew in over winter.
Then, alternate between Muck pellets and Weed Killer granules (weeks apart), for the spring and summer.
Aeration helps dissolve old vegetation and waste.
A soft layer of sand over the shale wouldn't hurt.