If you have a toddler who likes to play in the water, take them to Garden City Park in Richmond (and pack some boots and a change of clothes). Aside from manmade water features, it has a giant slide built into the hill, and many natural elements, like climbing structures made from trees and a gentle stream for kids to run in. It is not surprising that the playground was designed by children. I think that is what makes it so successful. It is built with an explorer's spirit in mind.