Below is a link to the Hill's Bark Park in Topeka; this site gives rules and much information about organization, etc.
www.hillsbarkpark.org
Our bark park is a converted softball diamond located in Gage Park (a large park in western Topeka containing a huge swimming complex, the zoo, miniature RR, flower gardens, shelter houses, playgrounds, carousel, theater, tennis courts, etc.).
After a small dog was killed by a larger dog several years ago, a separate annex for small dogs was added.
I've taken Puff there about 7 times hoping she'd play with other dogs but she only wanders around as if "stoned" by all the scents so we don't go anymore.
Instead, we started a weekly (Saturdays, 2-3) Labfest group.
Also, only 2 miles (3.2 km), 4 minutes, away we have a large nature preserve about 1 mile x .5 mile (1.6 x .8 km) in area with streams, ponds, woods, fields, deer + much other wildlife, and many trails lacing through it. Puff and I use this area early every morning for a 2 mile walk.