Thursday saw an expert questioned about conditions at the culvert at Premier Drive stream.
It is “extremely unlikely” that Noah Donohoe entered the storm drain where he was found dead anywhere other than the Premier Drive stream culvert, an inquest has heard.
The inquest, which is being heard with a jury, is now in its 17th week at Belfast Coroner’s Court, and heard further evidence from engineer and hydrologist Jeremy Benn on Thursday about the culvert.
Noah, 14, had set off on his bicycle from his home in south Belfast on the evening of Sunday June 21, planning to meet two friends in the Cavehill area in the north of the city.
However, he was later seen on CCTV footage cycling along York Road. The last sighting of him was on Northwood Drive.
Police believe Noah entered the nearby Premier Drive stream culvert, although there is no direct evidence such as CCTV or witnesses to support that.
His naked body was found around 600m further down the storm drain tunnel at a Northern Ireland Railways depot almost a week later on June 27 2020.
A post-mortem examination found the cause of death was likely to be drowning.
Mr Benn had previously given evidence along with three other expert witnesses last month.
The inquest heard all four thought it was “extremely unlikely” Noah entered the culvert system at any other point.
Mr Benn said the alternatives were manholes, which he described as having heavy covers, designed not to be easy to lift, and if Noah had entered via a manhole the cover would have remained off.
He said other parts of the watercourse were fenced off, while another section would have involved wading through deep mud, and the train depot where the section of storm drain where his body was found, is gated with 24-hour security.
Meanwhile, the experts were at odds over whether Noah’s body would have moved in the tunnel.
Mr Benn said Noah’s body could have moved a short distance downstream with the outgoing tidal flow, while the other experts felt any movement would have been short, less than a few metres.
The inquest heard Mr Benn was involved with drafting guidance on culverts in 2010 and 2019, and trained staff at Northern Ireland’s Department for Infrastructure on that guidance.
He was instructed by the department as an expert witness for the inquest.
Mr Benn was also described as having disagreed with the other expert witnesses over whether there should have been a security screen and fencing at the culvert which was refurbished in 2017.
On Thursday he warned that fencing in the area would have been very costly and difficult to put in.
In terms of security screens at culverts, he said they can lead to other dangers, adding that the flooding of the Westlink bypass in Belfast in 2008 was caused by a security screen at a culvert.
Counsel to the coroner Peter Coll KC, questioned Mr Benn on his assessment of the risk or hazards of the culvert.
Mr Coll suggested that due to it being dark, cold and the storm drain tunnel being so long and filling twice a day with the tide, that it was a “seriously dangerous place for a 14-year-old child, unauthorised, to be in”.
Mr Benn responded saying: “I wouldn’t go as far as to say it’s seriously dangerous.”
Returning to resume his evidence after lunch, Mr Benn said the culvert “wasn’t high risk” because of hazards being unlikely, terming it instead as “medium risk”.
