They're using Rhino Pipeliner 5000, which freezes as sprayed-on curds almost exactly as it hits the surface. Won't flow out, flatten, and self-level like standard epoxy or paint would. Under standing water, the orange peel texture is a perfect scaffolding for algae, bacteria, and general bio scum This shit shrinks 1-3% when curing, which in a pipe is exactly what you want. On a big slab, uh, no it will pull towards the center and delaminate from the substrate at the edges. Plus, applying directly to concrete is a problem. Long story short: Swiss cheese pinhole effect. Already flagged.
To avoid pinholes, mobility, and osmotic blistering, pros use geotextile. Thick, felt-like fabric gets laid out across a pond bed and anchored at edges. Flexible polyurea sprayed on the fabric, not the ground. Polyurea soaks into the fabric, cures. You get a seamless, reinforced rubber-like mat.
Rhino Pipeliner 5000 is not recommended for ponds. It's specialized for trenchless pipe repair, hence its rigidity and 3 second gel time. Other polyureas/polyurethanes are far more stretchable and good for continuous immersion. Baffled that Rhino itself didn't step in, maybe they did If Rhino Pipeliner 5000 (w custom flag blue tint) is indeed what they're applying, in around 5 years it'll be delaminating and peeling up in massive slimy sheets. So a perfect future metaphor for the Trump years inB4 capitol scum pond liner delamination