The Kirkwood Aquatic Center, partially financed by and shared with Glendale and Oakland, provides us the most wonderful relief from the St. Louis summer, a.k.a. the sauna experience. We'll probably start by lounging on a float tube as the current pushes us along the 700-foot Lazy River, past water sprays and under bridges. But we can't long resist the thrill of the slides -- the open flume and the tube -- that shoot us into a pool after 135 feet of wild twists and turns. If we're feeling more energetic, we might work out in the 25-yard lap lanes or use one of the 1-meter diving boards in the exercise pool. More likely, we'll sit on a bubble bench in the shallow adult pool and watch the younger children play in theirs, with its inviting zero-depth entry. They quickly discover the fun of the play structures, especially the huge bucket that fills until it tips to drench everyone strategically jockeying for space under it. We'll probably eat at the concession stand, because it has a full-service kitchen, and then lounge on a chaise at one of the many locations, feeling grateful for the shaded areas and pleased to see the aquatic wheelchairs making the entire complex easily accessible. Nestled next to Kirkwood Park, the multilayered landscaping -- rock work, waterfalls, shrubs, flowers -- makes the spacious Aquatic Center (111 S. Geyer Rd., 314-821-7665) an attractive and refreshing retreat from summer heat. Regrettably, those who aren't residents of the three sponsoring communities will just have to swelter -- so make plans to move before Memorial Day 2001, when the center reopens.