Filter/pump recommendations

[Indiananewbie]

Looking at pumps and filtration what's out there for me to choose ? 13x15 pond approx. 3 1/2 foot deep sole purpose looks and a place for my labs to swim /cool off no intention of adding fish or a lot of plants. I intend to have a waterfall feeding the top end and skimming / filtering the opposite end and pumping back up to the waterfall . Is this a normal way of doing it?

 

[KDubU]

I have a 5000 GPH for my to be pond and it will only be slightly larger than yours. I am no expert and this pump came with a kit I purchased for a 13x18 pond.