The eastbound carriageway has reopened but the westbound remains close, says National Highways.
Floodplain meadows are one of the rarest habitats in England, says the wildlife trust.
The bridge is open again after being closed since the start of the year.
Renovation project on track for reopening to pedestrians and traffic by 29 June.
Double-decker buses are set to operate on a different route from what was announced last year.
Installing a gate at a dumping hotspot has led to a "lasting solution", a council says.
"It's not my story anymore it's a Northampton story - it belongs to us all now," says Steve Pateman.
The family of Steven Leadbetter say he was "larger than life" and "died doing what he loved the most".
Police are appealing for witnesses and and dashcam footage.
