Cardiff Rivers Not Dredged for 6 Years
Natural Resources Wales said that the last time any heavy dredging happened in Cardiff's rivers was 2014 for the Roath Brook.
According to Natural Resources Wales, the last dredging operation on rivers in Cardiff happened in 2014.
Dredging is a process by which material is removed from bodies of water, whether it is silt, rubbish, or other debris.
The findings were made by media literacy charity The Student View, following submission of a Freedom of Information to Natural Resources Wales.
The body stated, “We do not currently undertake the heavy maintenance associated with dredging on any of the rivers in Cardiff, we believe that the last heavy dredging operation undertaken was in 2014 on the Roath Brook.”
A Natural Resources Wales document entitled ‘Roath Brook Flood Scheme’ published in 2017, stated, “The Roath Brook burst its banks most recently during high river flows in 2007 and 2009 and during high tidal events in 2010 and 2012. The likelihood of flooding will only increase over time, as a rise in sea levels and more frequent and intense heavy rainfall are predicted as a result of climate change.”
However, the document goes on to say that it chooses not to dredge the body of water because: “During times of flooding most of the water flows across the floodplain adjacent to the river channel. Dredging would slightly increase river capacity but not enough to reduce the flood risk in Roath or to prevent flooding in areas at risk of high tides. The brook is however to be modified in the area around Roath Brook Gardens; in widening the channel here, the height of the flood defences can be reduced.”
It added that it is not involved in the removal of any rubbish discarded into Wales’ rivers.
Parts of Cardiff were flooded during early 2020 when Storm Dennis hit the city and the River Taff burst its banks.
Tim England, Operations Manager – Flood and Water Management for Natural Resources Wales, said “Our maintenance work on main rivers is one important element of managing the flood risk across Wales. The work we do to keep these channels clear includes removing silt, vegetation and other obstructions from rivers and streams to maintain channel conveyance.
“We undertake de-shoaling as part of our flood risk maintenance work, but we rarely undertake dredging. De-shoaling removes the build-up of river material deposited where river channel flows are slower. For example, inside of river bends or where river channel naturally widens, or where large storm events have resulted in additional material being transported and deposited.
“Dredging, on the other hand, deepens and widens rivers beyond their natural state. It can be environmentally damaging and does not necessarily increase river capacity, as local dredging does will not always tie in with the hydraulic gradient of the river. Dredging can simply create deeper sections along a river that will fill up naturally as the river returns to its natural equilibrium.”