A Temporary Bridge Over Tumbling Bay Weir Is Feasible, Says Leading Engineer

Published on: 26 Oct, 2022
Updated on: 28 Oct, 2022

Remains of the weir footbridge shortly after its dramatic collapse in 2019.

By Martin Giles

The full repair of the Tumbling Bay Weir at Millmead is taking much longer than necessary and is costing too much. This is the opinion of a professional who was responsible for the weir as part of his role as a principal engineer at Guildford Borough Council (GBC) until 1987.

He also believes that there is a precedent for an inexpensive temporary footbridge to be constructed that would allow the towpath to be quickly reopened. The towpath has now been closed for three years.

Chris Shaw giving his talk at St Catherine’s Village Hall on Monday evening (October 24).

After the collapse of the weir in November 2019, Chris Shaw, a chartered civil and structural engineer, offered his experience and advice to those working on site but his offer was not taken up. He also wrote at length to the lead councillor responsible, John Rigg (R4GV, Holy Trinity), in May this year but no reply was received.

Mr Shaw told an audience during his talk, arranged by St Catherine’s Village Association (SCVA), whose members include those most directly affected by the three-year closure of the towpath, that a lack of local knowledge appeared to have hampered repair work resulting in the first attempt to install a temporary barrier failing.

The first attempt at a repair failed when bags of ballast lowered into the gap left by the weir proved insufficient to form a barrier and were pushed aside by the weight of water.

He had intimate knowledge of the weir because of his work on it as senior assistant engineer and then principal engineer between 1974 (when GBC came into existence) and 1987. In that period, with subordinates, he was responsible for the structural engineering aspects of work on the weir and river banks.

At that time, it appeared to him that GBC assumed financial responsibility for the maintenance. Mr Shaw said he and a colleague “inspected the area twice a year, decided what would need doing, and the required money was put in the budget.”

The civil engineer with local knowledge of the River Wey in Guildford was concerned that the clay bed of the navigation might have been damaged by scaffolding poles driven through it to dam the water by the rowing club.

During one maintenance project, he said that a former National Trust representative insisted that the towpath remained open and this resulted in a temporary weir footbridge being constructed.

The construction of such a bridge now, to reopen the towpath, has been suggested on numerous occasions. Mr Shaw believed this could be done at a relatively modest cost which he estimated at £10,000.

Recently, at another SCVA meeting, Cllr Tom Hunt (Lib Dem, Friary & St Nicolas) said that a temporary bridge had not been installed because of concerns about the associated liability risk.

The once popular towpath has remained closed now for three years.

The chartered engineer blamed the collapse on a lack of regular maintenance and questioned whether any had been carried out in recent decades up until its near-disastrous collapse under a pregnant woman, who had to leap to safety.

He agreed with others that the main reason for the lack of progress in effecting a full, permanent repair appeared to be the reluctance of the two main agencies involved, the National Trust and Guildford Borough Council, to agree financial responsibility.

According to figures given to Mr Shaw by GBC, the total cost of the repair to date is £1,125,800, with the cost divided between GBC and the National Trust, with GBC bearing roughly two-thirds of the cost. A revised total cost figure of £881,000 was later given by GBC.

On October 4 a spokesperson for the National Trust told The Guildford Dragon NEWS that they hoped to be in a position to be interviewed about the weir repair “very soon”.

Editor’s note: The Guildford Dragon has facilitated renewed contact between Mr Shaw and Cllr Rigg. On October 4 the National Trust said that they hoped to be in a position to be interviewed about the weir repair “very soon”.