This is a pretty clean storm drain -- except for one part, which is decorated with peni.
The drain is pretty new, we're talking the last 5-8 years. According to the stamps the drain pieces were made in '06 and '05.
This is probably one of the biggest storm drains I have seen. But like all drains there are parts where it fluctuates. The entrance is around 7-8 feet tall. Width is also pretty large, you can easily walk 3 abreast.
My friend and I haven't explored the entire drain. We came across several junction points, but only went through one of them.
Drain Sunnies
Junction (two 5ft~ and a 6ft~)
More to come! I'll bring my nice camera next time.