I do not know all the inner workings of BLD parks and they might change by state and site.... but...

Years ago BLD was talking with the city of Concord CA and I was a rep for the softball program...

BLD was trying to get the city to set aside 30 acres of what was, and is, an old armory (if I remember the size correctly) BLD was asking for free use for 30 years and they were willing to offer other perks such as maint. to city staff.

This same type thing was done in san jose at a complete called Twin Creeks...that developer got 30 years free and he paid for building... his son became the park/property director.