A mandatory evacuation order has been lifted for 135 homes east of Dartmouth along the Little Salmon River from North Preston to Lawrencetown — prompted by the threat of a dam breaching.

In an update Saturday afternoon, officials with Halifax Water said the necessary work has been completed and people can start heading home at 5 p.m. AT this evening.

Bridges over Highway 107 and Highway 207 were open Saturday, but four other bridges in the area were closed. They were expected to reopen Saturday evening once the evacuation order was lifted.

"Traffic barricades will be pulled from all the roads and bridges at 5 p.m., except those on Lake Major Road and at the intersection of North Preston Road and Johnson Road. Those barricades will be removed at 7 p.m. tonight to allow crews time to remove their equipment and exit the work site," Halifax Water spokesman James Campbell said in a release.

"The Route 61 through North Preston will remain on a detoured route until the barricade on Lake Major Road is lifted. Detour information is on Halifax Transit’s service disruptions page."

Campbell said 90 per cent of people under the evacuation order left Friday night by 11 p.m. The evacuation was prompted by the risk of flooding should there be a breach of the dam during repair work.

Campbell said the fish ladder at the Lake Major dam was damaged during the heavy rain event on Dec. 10. He said the damage was discovered during the inspection on Thursday.

He said some of the armour stone anchoring the structure was washed away during the Dec. 10 storm. The fish ladder is a passageway for fish to bypass the dam.

He said crews reinforced the structure Saturday with larger pieces of armour stone.

Campbell said the evacuation was "very precautionary."

"It's very prudent to evacuate folks in the event of safety. If anything did go wrong here, the chances of getting everyone out in a very short period of time are very limited," he said.

Campbell said the final design for a long-term fix has already been completed.

"We've already had a design contract awarded for the repair of this dam, so the long-term plan will be to actually make a complete repair of the whole structure. It's actually our number one priority," he said.

Dams in Nova Scotia are inspected every seven years, and also after every major rainfall.

Some bridges closed

A few Halifax Transit buses were brought in to keep pets, like Karm, out of the cold. (Anjuli Patil/CBC)

There were warming centres open for people who had to leave their homes.

The homes under the evacuation order were near the Salmon River, which flows from Lake Major. The affected homes were located in North Preston, Cherry Brook, East Preston, Westphal, Lawrencetown and Cole Harbour.

"It's been pretty smooth so far. People have been understanding, very cooperative. This is just a precaution, we're just hoping for the best," said Coun. David Hendsbee.

Cody Faught and his dog Karm went to one of the warming centres Saturday morning.

"I didn't want to leave her by herself, she might get a little bit upset," he said.

A few Halifax Transit buses have been brought in to keep pets out of the cold.