I'm needing to build a large trough. It will be 60" by about 148' with about 3' tall sides. I'm seeing that I allegedly should be able to remove the form for the sides after about 48 hours (I've never worked with concrete but that just seems super fast to me). This whole thing will be raised off the ground by columns about two feet or so. Now, obviously the bottom will need to be supported for much longer, but can anyone tell me about how long? and is it accurate that the form for the walls can be removed after only 48 hours give or take, depending on temperature?

Also, can this be done in sections? Say, can I do 12 feet, remove the forms, do the next 12' butting that one and then just work my way down 148 feet?

Edit: I forgot to mention this whole thing will only be holding 2" of water at the bottom and the walls will only be supporting like 30lbs/foot. Not sure if that matters.