McKee said there is no requirement to lock a hatch on a debris screen and an unlocked hatch can allow maintenance workers to open it in the event of a build-up of debris or flooding.
He also said an unlocked hatch can allow someone who became trapped inside to escape.
The witness said: “There’s actually a risk associated with locking hatches.”
Concern had been expressed following Noah’s death that he could possibly have gained entry to the culvert through the unlocked hatch at the inlet.
Noah was last seen running behind houses at Northwood Road, where back gardens run alongside the waste ground where the culvert inlet is located.
McKee explained that the only people who were known to have access to the area around the culvert inlet were the residents of four local homes.
He said they were therefore “more alive and aware” of any risk than other members of the public.
“The site wouldn’t have been regarded as being accessible to the general public,” he said.
A barrister for the coroner asked the witness if the department considered if it might have been appropriate to liaise regularly with local families about any potential risk at the site.
McKee said the department has considered this matter, but it could not be done in isolation at one location.
He said there are hundreds of other locations across Northern Ireland and if it was to be done at one location it would have to happen at all locations, and this could create potential administrative and logistical issues potentially involving thousands of people.
