The firm behind plans for an £1.8 million activity hub plan at Thirlmere has defended the scheme.
Treetop Trek want to install two zip lines and an 18km cycleway in the managed forestry around the reservoir.
The lines would stretch from one side of the lake to the other.
The plans have attracted a huge amount of opposition from Friends of the Lake District and the Open Spaces Society, among other groups, and thousands of people have signed a petition against it.
They say it will ruin the area's tranquil nature.
But Mike Turner, managing director of Treetop Trek, told the Financial Times: "The Lake District is not just for mountain climbers and fell walkers. It is for everyone. It shouldn’t be preserved in aspic."
Mr Turner said the Thirlmere Activity Hub will create the equivalent of 28 full-time jobs and attract an extra 127,000 visitors a year.
Mr Turner said: "Zip lines and cycle tracks are clearly not environmental matters – they are emotional ones.
The closing date for comments on the plan has been extended to January 12.
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