Archaeological investigations are due to begin at the site of a planned £100m reservoir in Cheddar, Somerset.
More than 180 trenches will be dug over eight weeks around Bristol Water's proposed site by expert teams from Wessex Archaeology.
"The programme is part of the environmental assessment to identify areas where archaeology is present," said project spokesman Jeremy Williams.
The results will influence the future design of the proposed development.
The Somerset Levels, where the trenches will be dug, are considered to be one of the richest areas for archaeological remains in Britain.