Loch Glascarnoch near Garve supplies water to Mossford power station.
A road that used to link Inverness and Ullapool, two bridges and part of a telegraph pole have been visible and were photographed by Calum Maclean.
Glascarnoch and its dam form part of energy giant SSE's Conon hydro electric scheme, which involves six dams and seven power stations.
The dams and power plants were built in stages between the 1940s and 1960s.
A new road to Ullapool was built to replace the one lost under Loch Glascarnoch.
SSE said the water level of the loch had been lowered for operational reasons.
A spokesperson said: "As we head into the winter we've pulled the level down because the rain we usually get in October and November can raise the levels up by as much as one metre a day."

Muhammadu Buhari said that if a credible Boko Haram leadership could be identified then he was prepared to talk with them without preconditions.
But he said he had no intelligence on the girls' whereabouts or their health.
Boko Haram seized the girls from their dormitories in the north-eastern town of Chibok in April 2014.
"If a credible leader of Boko Haram can be established and they tell us where those girls are, we are prepared to negotiate with them, without any precondition," said Mr Buhari.
Attempts to negotiate with Boko Haram during the rule of ex-President Goodluck Jonathan failed because officials were talking to the wrong people in the fragmented militant group.
BBC Nigeria analyst Naziru Mikailu says Mr Buhari's offer to revive talks shows that Boko Haram remains a force, despite his claim last week that the group had been "technically" defeated.
There is little prospect of Boko Haram agreeing to negotiate the release of the girls, he adds.
The militants regard the girls as their most invaluable captives and their leader, Abubakar Shekau, said last year that most of them had converted to Islam and had been married off.
Some Nigerians on social media expressed anger at the president for saying the government had no idea where the girls were being held, saying it indicated a failure of the intelligence services.
Mr Buhari took office in May with a promise to defeat the group, and gave the military a deadline of the end of the year to end the six-year insurgency.
Although Boko Haram has been driven out from most of the areas it controlled in north-eastern Nigeria, it has continued to carry out suicide bombings and raids into neighbouring Cameroon, Chad and Niger.
The military has managed to free hundreds of Boko Haram captives in recent months.
However, they did not include any of the Chibok girls.
Using football to tackle Boko Haram
Why Boko Haram remains a threat

The midfielder, 20, agreed to a five-year deal with the French champions.
He scored 13 league goals for Anderlecht last season to help them win the Belgian title.
"Monaco is a club with an ambitious project, recognised on the European stage, and which relies on young players," Tielemans said.
"I am very happy to be here. I will now do everything possible to progress here and repay the confidence the club have shown in me."
Find all the latest football transfers on our dedicated page.
Water levels at a loch created in the 1950s have dropped low enough to reveal structures usually hidden underwater.
[NEXT_CONCEPT]
Nigeria's president has said he is prepared to negotiate with Boko Haram militants to secure the release of about 200 schoolgirls.
[NEXT_CONCEPT]
Monaco have signed Belgium's young player of the year Youri Tielemans from Anderlecht for a reported 25m euros (£21.63m).