Digging next to arbor vitae and junipers- advice please

[sandman900SS]

I want to bury a 4" pvc tube downspout drain right in between a large, 50 year old arbor vitae (left) and old juniper bushes (on right). Arbor vitae roots are visible on ground, and no doubt some will be cut digging the trench for tube. Will likely have to go two feet deep.
My question is: how likely is doing this to wound or kill either of them? Should I be worried about this?

 

[sandman900SS]

Here's how the large arbor vitae looks from the other side. It's about 35' tall, a nice screening- sure don't want to lose it, but who can say with the inevitable damage to roots.

 

[Tetters]

The Juniper will have a big tap root , and the Arborvitae will have fairly shallow fibrous ones. I think they will withstand the damage you would obviously cause by digging through them - however, be aware that putting a pipe that carries water next to thirsty trees is asking for trouble, as the roots that are still there will gravitate straight to the water supply and probably grow into and through the pipe, and block it up anyway.
Maybe there is another solution to the drainage problem?
We like to use all the rainwater we can possibly store from the roof and gutters - or maybe feed a wildlife pond? Failing that, is there another route you could take?

 

[sandman900SS]

Greatly appreciate your thoughts here. Root damage is my #1 concern, and the pop up will be 8' away in the lawn, so I don't suspect the roots will gravitate toward the line, but who can tell until it's done.
No, can't collect and store rainwater in this situation- must direct water 20' away from foundation.

 

[Tetters]

With both trees so well established, I reckon you should be safe enough. I do hope so, and wish you luck with the venture