I just saw this post and thought I would throw this out there.
The best book I have read regarding hydraulics is "Fire Department Hydraulics" by Brent Hannig and Eugene Mahoney. It is a very good read if you are wanting the technical and practical side of things. You can buy it on Amazon.
Fire Department Hydraulics and Water Supply by Mike Wieder is also a good read. You can get it from the IFSTA website. Both cost about 70 bucks each.
Honestly the best way to learn about hydraulics is to get some inline pressure gauges, a flow meter, and a pitot gauge and go out and flow some water. It all comes togther when you do that.