After doing Bypass, toothdoctor and myself found ourselves in Rainbow Junction. The downstream culvert of Macro leads on from this, it's double barreled at the infall, but opens up to 3 someway in.
There was an interesting looking sidepipe and some vents letting daylight seep in, best of all something else lurked in the dark. A sidepipe led off to a sump chamber, absolute stillness, great depth and foreboding. Interesting place but you wouldn't want to fall in that water.