On-site parkland dedication in general is stupid. Folks get all swoony over Paley, and rightly so, but don't understand that it's a private, funded, secured, heavily manicured, experience. The City (no surprise) doesn't seem to get this and, to compound things, are moving away from cash-in-lieu which is going to lead to any number of random, poorly-maintained, open spaces, across the city.
On-site makes sense when:
1) The site is large, and a meaningful park is possible
2) The site directly abuts an existing park and the amount of land available can materially enhance that existing park.
It does not make sense the way it is being used by the City, the majority of the time.
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What should be happening is a process that looks like this (in my opinion) :
a) Decide which existing parks in an area (downtown for example) would benefit from expansion, and have adjacent parcels which could realistically be acquired and added to said park.
b) Decide which areas would benefit from a completely new park, consider whether the amenities desired/needed in that area can be realistically delivered on the parcel(s) available.
c) Immediately apply an 'H' zoning to any parcel prioritized for acquisition, blocking it from being anything but a park; and/or rezone it parks/open space with the existing use as legal, non-conforming.
d)Acquire those properties that have owners insistent on or willing to sell now, immediately, off-set this with existing cash-in-lieu and direct budgetary expenditure.
e)For lower priority parcels, with owners willing to accept the above zoning and maintain existing uses, acquire them as cash-in-lieu becomes available.