As well as being at full capacity, they are worried that the present bridge may collapse because it was built on the cheap and uses the same style as a bridge in Minneapolis which collapsed in 2007.
The location of this bridge was chosen because it was the closest they could get to New York City without the bridge coming under the Port Authority who would have demanded the tolls. Compare with the Thames where the City of London's control of the river extends a long way up and downstream from the city.

Officially Sing Sing Correctional Facility. Americans still cling to the notion that prison can correct people. They bang up 478 per 100,000 of their population — three and half times the European rate.
I found this undated image on this web page. Curiously, I need to flop it to get a very close match to my image:

The telephone poles nearer to the tower are gone but the lattice towers carrying various railroad cables seem totally unchanged.

This map dated 1931 shows an area of marsh. Since then its use as a landfill site has turned it into 30 metre high hill. It has now been capped off with soil but such sites continue to generate methane for years afterwards. This manhole is one of the methane vents.

I think these rock filled ditches and embankments are are to catch storm water and prevent big flows which might carry soil away.