Your total headloss through your system is not just the vertical lift. You will need to estimate the losses through the pipe, any turns (90° or 45°) or valve units. Backflow preventers will also induce some headloss. The loss through your lines is a function of the velocity through the line and therefore the diameter of the line. Are you running 2" pipe or running something smaller? Finally, you need to decide what type of flowrate you want in your cascading waterfalls....do you want to believe you're at Niagara falls or are you wanting a modest trickle?
There are numerous headloss calculators out there but you need to get a rough idea of what the current flowrate is, and if you can accept something less. It would appear that the pump you are thinking of choosing will certainly lift water up to your high point. Whether it will be enough???? Can't tell without more info. Also, look up the pump characteristics for your current pump (you didn't specify the make and model) to compare headloss versus flowrate with the pump you are thinking of choosing. That may provide a quicker answer.
---David

Thanks for the quick answer,
My current pump,(the one I want to replace), is a Chicago 1.2HP, 7 working amps, 61GPM (3660GPH), 28ft lift. I figured this pump uses about 840 watts and is not very efficient. This pump is giving a good flow rate and would like the replacement pump to have the same. I have no idea how many turns there are because I just bought this house and the pond was already installed, but the piping is 1 1/2 diameter. Keeping the same flow rate would be good. I am a newbie at ponding so some of the terms used to describe the pumps operation are foreign to me.
Here is a link to what looks like the current pump I am using. --> http://www.harborfreight.com/12-hp-3700-gph-dirty-water-submersible-pump-with-float-93820.html
Please let me know if you need more information or even pictures...
x

More useful information (I think). The spillway/creek bed width is mostly only about 12" wide but has one spot where it widens to about 30". The average width would probably be about 18 to 20 inches. The spillover thickness of the top waterfall is probably less than an inch, it is hard to tell exactly.
I found this calculator online --> http://www.your-garden-ponds-center.com/waterfall-pump-calculator.html and according to my estimates, the aquasurge 4000 should do the trick. I don't want too much pump but want something that will give a good sheet over the weirs.
Thanks again,
x

Can't seem to find the head curve (the flowrate of the pump as function of head or height of water) or table for your pump but making an educated guesstimate I'd say you're probably in the neighborhood of 10-12 feet taking into account the 1 1/2 inch pipe and approximate length. It appears the pump you propose to use should just about handle this although I suspect it might be a little bit less flow. It will certainly save you money!
There is another alternative IF you can convert your layout from a submerged pump to an external pump. The URL listed below should connect you with a website talking about Wave pumps - look at the 2 speed, 3/4 hp pump -- the two speed pump (but not submerged) would definitely handle your situation. When you don't care about having the water really roaring along you can run it on low speed and save money. When you've got guests or just want to listen to or look at the waterfall in full flow, flick a switch. 'Tis a possible alternative.
---David

Here is a link that might be useful: Wave pumps

Thanks for the tip, the external 2 speed does sound like a good option. I will run this alternative by my wife and go from there.
Thanks again David!