Blocked pipes, drains and problems with pumping stations may have made worse the damage caused by a "one in 50 year" flood event.

That is one of the conclusions of a Denbighshire Council report into the flooding that saw almost 100 homes and businesses flooded on July 19 last year.

Rhyl, Prestatyn, Rhuddlan and St Asaph were all badly affected by flash flooding.

The torrential downpours also inundated parts of Conwy, Anglesey and Gwynedd, shutting a lane of the A55 and forcing the closure of a hospital in Abergele.

Sewers in parts of Denbighshire were simply unable to cope with the sheer volume of water that flowed, a report, prepared by the council's flood risk manager, found.

The council's scrutiny committee heard 98 properties were flooded. Rhyl was the worst hit town with 47 homes and businesses inundated.

Prestatyn had 33, including 27 on the High Street, Rhuddlan had 11 and in St Asaph the number was seven.

An investigation, lasting several weeks, by council officers found that the flooding was caused by surface water and it was made worse by blocked drains.

The report said: "The flooding that affected Denbighshire on July 19, 2017 was, statistically speaking a rare event. According to reports provided since by Natural Resources Wales and the Met Office, the return period of the rainfall event was around 1 in 50 years.

"This means that there is a 1 in 50 chance of a similar event occurring in any one calendar year.

"The flooding that occurred is best described as a pluvial event, that is, due to surface water, rather than emanating from a watercourse. Rhuddlan, Rhyl and Prestatyn are served by combined sewers, which carry sewerage as well as surface water.

"These sewers are the responsibility of D?r Cymru Welsh Water and many failed to cope with the volume of flows, which exceeded the capacity for which they were designed.

"Investigation work that D?r Cymru Welsh Water has carried out since the event indicates that blockages in pipes and problems with pumping stations exacerbated the flooding, but did not cause it," the report added.

The council is working with D?r Cymru and Natural Resources Wales to carry out a drainage study at Ffordd Derwen, Rhyl to look into whether improvements can be made to the management of Rhyl Cut and Prestatyn Gutter, as well as adjacent drains and sewers, with the hope that flood risk can be reduced.

Both pieces of work are ongoing and should be complete by September.

In November the UK Government will release its climate projections which is expected to say that this type extreme rainfall will happen more often.

D?r Cymru has been asked to comment.