I am interested in installing a system like this

http://www.ponddampiping.com/syphon1.html

I was worried about the water freezing in the 45 deg ell on the back side of the dam. Could you just use a 22 deg instead and put some kind of trash type guard on the end to keep the critters out? Or is there some other reason for the 45? Also I notice that this system does not have a collar on it in the core of the dame. Would it be beneficial to add one?