[retiredguy123]

Mine just drains aboveground to the concrete slab inside the gate using a short connection piece from the downspout. That is the way the builder installed it. I have two of these aboveground pieces and downspouts inside the gate. No issues. Why do you need to use an underground tube from inside the gate to outside the gate? I would rather have the water draining inside the gate. I would remove the green popup and cover the area with rocks.

Note that if you try to drain the water into the confined rock area near your front porch, I think you will have continual maintenance issues. There will be a lot of water flooding that area.