PEMBROKESHIRE COUNTY COUNCIL is to spend £40,000 on a feasibility study investigating alleviating the risk of flooding at Lower Priory and Havens Head in Milford Haven.
The local authority has included the cost in its capital budget for consideration at Monday’s (Jan 13) Cabinet meeting.
The £40,000 cost of the feasibility study will be met through a £38,000 grant from the Welsh Government. The Council will contribute £2,000 towards the study, although the report accompanying the budget notes that funding may be secured from alternative sources.
Lower Priory and Havens Head were both subject to flooding in November 2018.
The flood at Lower Priory was catastrophic, causing damage to properties and inundating the Priory pub, causing its closure for many months.
Residents of Lower Priory pointed the finger at the massive amount of infill work on land leading from watercourses passing through the area towards Havens Head and the docks beyond. They also claimed failures of maintenance had blocked the trash screens on culverts.
Natural Resources Wales observed at the time: ‘The area affected contains two smaller watercourses that flow through a small valley through a culvert under a road/railway and into Milford Haven marina. The bottoms of the valleys are always wet and one has also been partially impounded to form a lake, which means the area can become tide-locked during high tides.
‘That coupled with the rain meant lots of water coming down the valley and lots coming in via the tide’.
While maintenance of the two minor watercourses is the responsibility of the County Council, once the watercourses pass on to land owned by Milford Haven Port Authority, responsibility passes to it to ensure its culverts are maintained and trash screens kept clear.
The Council does not have any powers to make landowners amend existing culverts to increase their capacity.
New developments have to comply with specific planning guidance from the Welsh Government. That guidance means surface water from an impermeable area created by a development (ie at Haven Head) must be dealt with through sustainable drainage systems (SuDS) which allow water to seep out via soakaways.
That standard has applied to all new developments for several years now.
The current situation, in which a large area of land is concreted over at the end of a watercourse, would no longer be permitted.
Following the flooding in November 2018, both the Port Authority and the Council tried to blame each other for the flooding.
A large amount of work subsequently took place to clear the areas around the affected culverts, including the removal of a significant amount of fallen trees and other vegetable debris.
In June last year, the Port Authority claimed that it was not liable for the flood damage and said the major factor in the flooding was a large increase in levels of silt in the lakes at Havens Head and Lower Priory combined with high tides and unprecedentedly levels of rainfall.
However, under questioning before a Council Committee, a Port Authority representative conceded its electronic flood warning system had been a casualty of the flooding and had stopped recording the water volumes at Lower Priory well before the peak of the inundation.
Information about how much infill was used around the watercourses is unavailable.
A recommendation in a report by contractors Atkins, who proceeded only based on information provided by the Port Authority, recommended the culverts should be increased to handle three times the volume of water they dealt with currently.
