alright, constructive criticism.
You'll progress in mapping far faster if you try an actual gameplay map. I'd suggest 5 point CP map. All achievement maps will teach you, is how to make brushes, add water, add player starts... The hard part about mapping isn't knowing how to do something, its knowing what to do. Making a balanced map is harder than just knowing how to use func_detail.
So, that said, how is making an achievement map going to teach you the ins and outs of mapping? It won't. It will teach you how to use basic functions of hammer, beyond that is wishful thinking.
You say you have other map ideas. Why can't you start them? make an intel room for a ctf map, don't worry about the rest of the map. Make a center CP for a cp map, don't worry about the others. These were all contests in the past and will help you far greater than making a map to help people cheat at the game and grow their achievement egos. Just because your map idea (probably) has lots of detail, doesn't mean its meant to start out that way, most maps start out as rough dev textured blocks, and progress from there. So saying achievement maps are the only thing you're capable of is suspect.
Achievement maps are one of the many plagues of TF2, which compromise what the devs have in mind for the game. Therefore I can't justly support them.
Edit: On the topic of water, perhaps making them on the same plane (same water level). Or blocking one another from vis. Or the easiest and quickest, use cheap water.