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Conwy Valley Flood News

Join Council, Natural Resources , Fire and Rescue Service and Dŵr Cymru/Welsh Water at a drop-in session at Glasdir, on the 25th April between 3pm and 7pm to discuss the recent flooding in March. We would welcome your views. Conwy valley floods March 2019 The Conwy reached its highest ever recorded level at Cwmlanerch on Saturday 16 March. This newsletter explains what all the agencies involved did to prepare, react to and are now doing to learn from the event. Natural Resources Wales

It’s encouraging to note that the At its peak, the same amount Conwy valley flood scheme once of water as in an Olympic-sized again successfully defended swimming pool was passing properties in Llanrwst and Llanrwst every four seconds. from flooding. In 24 hours the equivalent of flooding to homes in Conwy around half the water stored Terrace. A new permanent system Despite what some people say, in Llyn Celyn ran through the to replace the Dutch Dam will be it works by allowing water to valley. in place by the autumn. flow onto the valley floor at Pont , using the natural Unfortunately a few properties Some flood banks and other floodplain. This means the did suffer flooding and we assets have been damaged water in the river does not rise obviously sympathise with during this event and we will any higher, which would mean those people affected. Conwy be repairing these as part properties in Llanrwst and Council will be leading a review of our routine maintenance Trefriw being flooded. of the event to see if anything programme. can be done better the next We had a number of pumps At , 122millimetres time floods threaten. of rain fell in just 15 hours. This is outside Cartref y Borth and are 75% of the monthly average for Learnings so far reviewing how they were used to see if the system could have been March and is the most amount A recent exercise showed even more effective. of rain that has fallen in 15 hours that we needed temporary since records began in 1997. barriers at Llanrwst because You may have heard by now Significant rainfall was also the “Dutch Dam” was broken. that the National recorded at many other gauges These temporary barriers were is reviewing its plans for this in the area such as , successfully put up during the summer’s event and we are Llanrwst, Betws y Coed and weekend of 16 March. Conwy working closely with them to . County Borough Council are ensure a safe and successful investigating the cause of festival. Mythbusting Welsh Water A number of incorrect statements have been circulating in the wake As well as providing a of the floods. These are some of the ones that we have picked up on. continuous, high quality supply of drinking water, Welsh Water Floods happen because the river hasn’t been “dredged”. Dredging often – your not for profit water does not work and can often make matters worse by undermining company – is also responsible defences. We did recently remove some gravel at Bont Fawr to help for taking away, treating and us improve our flood monitoring and flood warning systems, but properly disposing of the this would not have reduced flood levels in the valley. wastewater that is produced. The key to the temporary barriers was in . We don’t need a key This is manged through a vast to put up the temporary barriers. All the equipment we needed was network of sewers, some of easily accessible at our Tan Lan depot. which carry only foul waste, The scheme to protect houses in Llanrwst increases flooding at Gwydir others carry foul and surface castle. The opposite is true. The scheme allows floodwater onto water while others carry just the floodplain by Pont Gower, rather than “backing up” and rising surface water. upstream. This means that the depth of floodwater upstream of Pont Villages in the Conwy Valley have Gower (including the garden at ) is lower than what it a combination of all three and it’s would have been prior to building the flood defence scheme. our responsibility to ensure they Why won’t you build a scheme to protect Gwydir castle? We recognise are maintained and kept free the historical significance of Gwydir Castle and its value to the Welsh of blockages so flows can pass cultural and physical landscapes. However, the risk of flooding is through them. During periods to the castle’s gardens and an uninhabited cellar. This means there of heavy rain, they can reach are insufficient benefits to justify investing in a flood alleviation capacity if too much surface scheme at Gwydir Castle. Flood risk management funding in water enters them. Wales is provided by Welsh Government and prioritised towards During the bad weather, we communities where flooding could pose a risk to life, as per the received a small number of calls Government’s policy. from the Conwy Valley area Flooding can be prevented if ditches are blocked in the uplands and reporting sewers overflowing. more trees grown. This can help reduce the risk of flooding but will Our teams attended at the not prevent it. The National Trust has already done a lot of this kind time in response and further of work to block old land drains on the and we are working investigations are now taking with them on other measures in Cwm . place to determine if the overflowing was linked to operational issues on the system or to the extreme weather conditions. We will continue to work with all agencies involved to help understand the impact of the weather on the area and identify any lessons that can be learned. If anyone has any issues relating to their sewer network we would encourage them to call us on 0800 085 3968.

Photo Natural Resources Wales Council

What we did during the flood The extreme weather events of Work during the weekend the weekend of March 16th/17th included: were very demanding for the Conwy County Borough Council • Clearing trash screens and gullies out of hours response teams. • Updating residents at • Unblocking drains and culverts Council staff were working on immediate risk of flooding flooding issues from 7.30am • Inspecting and investigating • Visiting and assessing until the last call at 11.45pm on highlighted locations households at immediate risk of Saturday. This was immediately • Deploying sand bags to divert flooding followed by gritting all priority water flow • Liaising with Natural Resources road routes overnight and • Setting up road signs warning Wales, , on Sunday morning, before of flooding and/or road North Wales Fire and Rescue returning to flood clean up closures, and revisiting regularly Service, emergency planners, and investigation works during RNLI and rescue Sunday. • Taking more than 100 calls from affected residents • Road sweeping to clear debris • Repairing damage to road surfaces • Clearing landslips The Council has telemetry (monitoring hardware) installed as part of flood alleviation schemes. This allowed Flooding Officers to remotely monitor water heights and blockages on Culverts at Cae Person, watercourses, managing Llanrwst on Friday 15th March the local flood risk better Photo: Conwy County Borough Council and using our resources efficiently. Using this information, teams were sent to take action where it was needed, such as clearing a build-up of debris. For example, the trash screen at Plas Isaf in Llanrwst was cleared within 30 minutes of the telemetry alert.

Culverts at Cae Person, Llanrwst on Saturday 16th March Photo: Conwy County Borough Council

Cae Person culvert - peak level at 3pm on March 16th

What we are doing now On Monday 18th March after the flooding, Flooding Officers began working across the affected areas, knocking on doors and filling in flood questionnaires with residents to identify the actual extent and number of properties affected.

By Thursday 28th March, our officers had visited Llanrwst, Conwy, Gyffin, , , Old , , , Betws y Coed and Trefriw.

We are also following up on all phone calls received during the flooding.

We will use this information, along with inspections of culverts and gullies, to target future investment in flood alleviation works to reduce the risk to the The latest Conwy County residents have the information local population. Borough Council Resident they need to be prepared. Bulletin was delivered to We are working on nine separate What we will do next households in February 2019 flood alleviation schemes to Although residents seem to be and contained advice for flood further reduce the flood risk to aware of the flood risk during preparation. Our website also has communities within the County, significant rainfall, the Council information on flood preparation in partnership with the Welsh wants to make sure residents and protection (www.conwy.gov. Government. have information about the uk/flooding). things they can do before flooding happens to avoid We will be looking at what other domestic damage. ways we can use to make sure