I moved up here from Colorado for a temp
assignment in Spokane this summer. Colorado has
started buidling these park and play holes like mad
for one very good reason: They bring in massive
tourist dollars as long as they flow. For a cost of
$140k  a large part of which came from federal
grants, and a 20 yard section of state land on the
river at the pre-existing boat launch, it's
estimated that the hole in Salida CO brings in
$3million to the community over a 3 month season. 
Aside from the fact that it would it be fun, it
would be good exposure for the boating community.
You wouldn't believe how many non-boating tourists
stop to watch, shoot pictures, eat lunch, etc at
these new park and play holes. With the exception
of trash collection, I can't think of a single
negative aspect to a park and play holes.