To move rainwater further away from a foundation than the standard 2~3 foot above-ground downspout extensions, what are the underground options?
Example of standard downspout extension:
(Photo from carlsonexteriors.com)
When searching online, I see many examples of a downspout connecting to several yards/meters of flexible underground pipe which then raises to a "pop-up drain emitter". They open to allow water out, and close when the inside pressure drops, blocking water from entering from above.
Example of a pop-up drain emitter:
(Photo from kisseutopia.club)
Are these pop-up emitters necessary? Couldn't the underground pipe just have an open end with a grate?
I find the pop up emitters to be rather unsightly, especially next to a public sidewalk (which would be the maximum distance away from the foundation).