The inquest has also heard that it could not have been foreseen that “a trespasser” would enter land linked to the schoolboy’s death.
The inquest has been exploring the possibility that the 14-year-old entered a structure leading to an underground drainage system after he disappeared.
The boy’s body was found more than 600 metres downstream.
Noah was last seen running between houses at Northwood Road in the direction of private back gardens.
The back gardens adjoin land on which the concrete and steel entrance to the underground drainage system is located.
The Department for Infrastructure has faced criticism at the inquest about the safety measures it had in place around the structure.
One expert on health and safety, Dr Mark Cooper, previously told the hearing that he believed fencing or other “reasonably practicable” safety measures could have been put in place as a deterrent to unauthorised access from the Northwood Road direction.
Giving evidence at the inquest on Wednesday, during his fourth day of evidence, Jonathan McKee from the Department for Infrastructure explained that the department does not own the land on which the culvert structure is built.
McKee explained that the department gains access rights to the site under powers granted for the purpose of drainage works.
He said the suggestion of additional fencing on the land was therefore not “reasonably practicable” because homeowners at Northwood Road are regarded as the ‘riparian owners’ of the land.
This means they have rights and access to the land behind their homes where the watercourse runs.
A barrister for the Department for Infrastructure asked the witness if it could have been foreseen that “a trespasser” could get onto that land.
McKee said it could not have been anticipated because the land is surrounded on different sides by a combination of high fencing, hedging and four local properties at Northwood Road.
One theory being explored at the inquest is that Noah may have entered private back gardens to gain entry to the adjoining ‘riparian owner’ land where the entrance to the underground drainage system is located.