Just an FYI: If you are ever in the Dallas/Ft. Worth/Arlington area, check out Six Flags Over Texas' Yosemite Sam and the Gold River Adventure (YSATGRA). It, like the Madagascar ride you reviewed, is a slow moving water dark ride and, more importantly, an unexpected, hidden treasure. I was impressed by the attention to both detail and story that this experience offers (especially considering my general disdain for anything SF related) . While YSATGRA is definitely a Disney-on-a-budget attraction, it is very well imagined and maintained, and should not be missed by any true theme park fan.
Just to let you know, Rye Playland's The Old Mill in New York is a water based dark ride. Also Six Flags Over Georgia had one in the 70s with The Okefenokee Swamp.