There are a few options for creating lakes in CAW.
For those at sea level:
1. Check out Nilxis' tutorial on making a beach, it describes how to gently slope the beach (which you could use for lakes as well). It just involves creating terrain "steps" with the flatten tool and then gentle smoothing the steps. http://nilxisdesigns.blogspot.com.es/2013/01/como-hacer-una-playa-de-arena-facil.html
Nilxis also has some other really great tutorials if you want to check them out, including some decorating tips.
For those above sea level:
1. Water planes - mod the sims has tutorials on this, but I always found it to be somewhat complicated.
2. SuperCAW pond tool - if you have SuperCAW or download it, it has a pond tool that can be used to carve out lakes and ponds directly in CAW. However, it has known issues, one of which is that if you're not careful it can flood your entire world, and cannot be undone. My suggestion with this is to save right before you use it and make sure the pond/lake has edges above where the water level will be all the way around. If it does flood, exit without saving and reload the world. I've been using the pond tool for years and find it's a decent work-around with careful use.
3. Make a "pond" in a lot using EIG - it won't be part of the official world water, but if you're going for just aesthetics and fishing use, this will work well. If you want boats to use it, this is not a good option.
Hope these help! And if you don't have a world showcase thread already, you should make one so we can watch the progress! :) <3
