Even with your description, there is a lot of information unknown so it is always helpful to see a photograph of the overall situation ... in case there is something relevant but not mentioned, and for us to better understand what is described. A landscape architect or drainage engineer could direct the grading work. Since there would be planting to occur after the grading is finished, the LA could handle it all. Some landscape designers and grading contractors could handle grading design, too. You'd need to inquire of anyone if they can/will do the work you're after.

"Since the pool is level, the surrounding paving area and grass beyond had to be elevated." It is not clear what you mean or why one would follow the other.

A big mystery is the deck and how grading could occur below it if it is low to the ground

since you're trying to find the right professional, one thing to consider is the laws pertaining to what you want to do. In many places, if you're disturbing more than X sq ft, you need to submit a grading and drainage plan to the city or county. If you think you'll be draining onto/otherwise impacting the wetland, you may need similar documentation. I'd start with getting either a landscape designer or landscape architect on site to review the conditions and potential issues. While this is something that a lot of grading/excavation contractors could do, it's hard to know as a layperson which ones need a plan to follow and which ones don't.

Quoted: "Since the pool is level, the surrounding paving area and grass beyond had to be elevated." It is not clear what you mean or why one would follow the other.

A big mystery is the deck and how grading could occur below it if it is low to the ground.

Thanks for the response. In answer to your questions: the pool is level, but as I said, the original slope of the yard was about 5' down from the house to the rear property line. So, the back edge of the pool was 4' above the original grade and fill had to be added around it. As to the deck, there is a 4' high crawl space between the underside of the deck and the grade below.

I am trying to get more photos and will also be contacting the original engineering firm who provided a grading plan ... which through a series of missteps and changed contractors on my daughter's part was not conformed to.

This is after 3-4 hour deluge of about 3" of rain. Notice not just the fact that the pool and pavers are underwater but that the surrounding lawn is as well.

If you already worked with an engineering firm that has been to the site and created drawings, and they weren't followed and now you're having a problem, I would start with calling them. They're going to be the fastest and most accurate way of determining what does and does not conform to the drawings, and what necessary next steps would be. Anyone else will need to come out and do a full topo and essentially reinvent the wheel.

The picture well explains the problem. I think you are getting great advice from Revolutionary Gardens. When you get a chance, take a picture square from the side so we can see the perpendicular view of the pool ... especially the farthest portion. And a picture of the below deck area.

I think you might want a network of french drains, not grading.

Just a temporary PS: I have just discovered, after my first chance to see the grading plan, that it appears that the pool was installed 3-4' below the engineer's drawing. If this is true, there is no way the existing grading could have been made to work without extensive excavation. We are pursuing remedy with the pool installer.

Presuming that the pool deck itself drains OK, with storm water running to its outside edges, it seems like it would be quite easy to make the yard drain. It looks like each side needs extremely gentle swales and that there is a pronounced slope toward the back lot line, and even lower elevations beyond. The hedge that's planted around the pool perimeter ... is it raised above the pool decking? It seems odd to me that anyone would want their pool enclosed by a hedge so closely to the deck ... or they would want a hedge obstructing the view beyond the pool. Even if they want these things, there is no space allowed for growth without impeding the pool deck area.

We have no knowledge of the land and grading located uphill of the pool deck area. Presumably, there will be water coming from that side which needs to be routed safely before it gets into the back yard. Is water graded away from the house foundation all around?

It looks to me that regrading to drain wouldn't amount to more than pushing some soil around on site, balancing cut and fill. There doesn't seem to be a true berm around the pool, but only some high soil to remove. To do that and create a gentle swale beyond it doesn't look like massive amounts of earth to be moved. Yet farther downhill beyond the pool is a substantial area of lower elevation. It looks like there'd probably be plenty of space to deposit any soil moved from farther up in the yard.

We have started legal action

Good luck. Report back on the resolution once you have it.