Would like to put in pond roughly 5' x 8' by 2.5'. What do I need though? Do i need uv sterilizers? Skimmer? What about filters? I would be digging the hole and laying the undelayment, not using the hard plastic casings.
Ponds what are the NEEDS
A skimmer, a pump and maybe a waterfall filter would probably be a minimum. You will need more filteration if you want fish. A UV isn't absolutely necessary but will keep you water clear.
Something else that has been discussed recently is a bottom drain. After reading the various posts I think it would be worth investigating for you since you are in the planning stages. I would definately recommend a UV light. There are a lot of filters that have UV lights included.
Are you putting fish in the pond? If so, consider going a little deeper (at least in the middle) so that they can hibernate in the winter. I live in zone 5 (Chicago area) and this is very necessary for our cold weather climates. Also, consider built in shelves for your plants. Some plants require a certain amount of water over them and some aren't too picky. Do you know what kinds of plants you plan to put in? If you like the water lillys consider that they prefer still water (water turns clockwise in a pond (to the left of my waterfall if where my water lillys live-at 3 feet-4 feet deep). I wish I could draw a picture of what I mean.
I was little concerned that the 2.5' wouldn't be quite deep enough for the cold winters. As far as plants I don't know. I haven't gotten that far. Right now in very beginning stages of planning. Trying to figure out the cost to start off with and then go from there.
Here is what I am running and have run it for years. I do not have a skimmer but it would have been nice. I have a large pump that runs my waterfall because I like a lot of water force. I have a smaller pump that runs my external filter and UV. That water runs through those and then out another water feature. I used to have an internal filter and that was a mess to clean. Live and learn. I have problems with birds and snakes, so I have my pond netted.I have goldfish and shubunkins in this pond and they have done very well. The pond is only about 2.5 feet deep. It has shelves for plants
I am currently planning a second pond, which will be much deeper so that I can put koi in there. It will have a waterfall, a skimmer, two pumps, an external filter, a Uv, and possibly a bottom drain.
I'm in Nebraska too and if you are just going to keep goldfish 3 feet should be enough. I went to 4 feet just in case I got bitten by the koi bug later on:)
I live in zone 5 and my little ponds are both at or about two feet deep. I have a few koi in one and goldfish in the other. Both made it through the winter without any problems. I did have a heater in the koi pond for about half the winter and then it died. The koi did not. I have never had a heater in the goldfish pond.