LEBANON — Ramp closures on interstates 89 and 91 will start Wednesday as construction crews finish work on the I-89 Southbound bridge over the Connecticut River, the New Hampshire Department of Transportation announced Monday.

The I-91 Northbound Exit 10A off-ramp that directs traffic onto I-89 will be closed Wednesday from 8:30 a.m. to 3 p.m., and again from Monday, March 31 through Wednesday, April 2.

The I-89 southbound off-ramp at Exit 20 will be closed Thursday, April 3 and Friday, April 4.

The ramp closures are intended to allow crews to conduct drainage and road reconstruction work to prepare for an April 4 traffic shift onto the new bridge, according to a “weather dependent” schedule.

Detours will be in place.

For Exit 10A northbound, travelers can change directions via Exit 12 in Wilder and take I-91 southbound to the Exit 10A off-ramp.

For Exit 20, a detour will direct traffic off of I-89 southbound at Exit 19 in Lebanon to reverse direction to Exit 20 northbound. This is also the detour that is currently in place to avoid the closed dry bridge that connects the village of West Lebanon to Route 12A.

— Clare Shanahan