Northern Light, you're the expert. Can this really be built for $10 million?
Ty for the compliment, but this exact type of work is a bit outside my area of expertise. (large-scale soil remediation in particular).
FWIW, based on my experience, and what I've seen of costs for other projects; the vast majority of the base elements, subject to how much is being spent on planning/presentations etc. is within the do-able range, albeit without that much wiggle room.
Remediation costs have come down a lot in recent years, but that's still a very large volume of soil to be removed and I'm somewhat skeptical as to fully covering that cost inside the allotted budget.
My gut instinct is 12M and don't make any mistakes or exceed moderate contingencies and your fine.
Anything less requires some very good material sourcing and very tight labour management.
But that's very much guestimating on my part, since I haven't seen the line-item estimates here.
Let me offer this comparison.
Cormier-Designed Berczy Park ran just over 7M on 0.8 acres.
This site is 2.0 acres.
Assuming you simply scaled to size, you'd be at 17.5M
Clearly this design will not have some of the costs associated w/the ceramic dogs, and the water feature, while larger is somewhat simpler to execute.
However, designing it to hold ice all winter, and have heated steps, amongst other features also add some costs back.
You do have some fixed cost irrespective of size as well, so scaling is an oversimplification.
In then end, 12M would be do-able to me, but challenging and the open question on remediation costs.
I'd really struggle to see it come in much cheaper.