Environment Agency Flood Alert 30 January 2021 – River Wey Valley debrief
Many River Wey Society members will recall the very heavy rainfall experienced overnight on 29 to 30 January and will be interested in the outcome. This report has been distilled from various eyewitness reports.
The significant rainfall in the Wey Valley started about 2330 on the 29th and continued until approximately 0700 on the 30th. It fell on already heavily saturated ground so run off was swift. The water table level was already high, so with a 2.3 metre spring tide in Weymouth there was already a dangerous cocktail brewing.
In Upwey, 25.7mm of rain was recorded. There were only minor breakages of the river banks and there were no reports of properties flooded. The gauge in the culvert just north of the schoolroom showed a maximum reading at 0400. The Environment Agency Flood Alert was issued at 0656
In the Broadwey/ Littlemead area the gauge warned of possible flooding at 0300. Again, while no properties were flooded, the picture of the appropriately named Watery Lane by the disused railway bridge demonstrated just how much water was racing down the valley, to meet up with the eastbound flow from Pucksey Brook. This enhanced torrent sped down towards Nottington; the gauge there recorded 90 at 0500 and the meadow to the north of Greystones was completely flooded. Interestingly, by 1300 it had remarkably dropped back to a reading of 50. Property owners in Nottington again reported no water ingress.
The water meadows (flood plain) between Nottington and Radipole were fully activated and flooded by 0600 with the highest water levels at Meadows Mill peaking at about 0800. It is important to note that the pre-emptive action of opening up all the sluice controls at Meadows on the 29th had lowered levels here well in advance ; a really good move. !
It was certainly predictable that with the double whammy of high spring tide and rainfall timing, the lower reaches of the river would be overwhelmed. From the bottom of Manor Road, no river could be seen but there was a very large lake, filled with muddy, alluvial enriched water. Happily, again no flooding was reported although there was concern that the houses by the Radipole Village bridge were at a high risk.
How did we know all this? Your RWS River Watch Officers were ready, alert, up and about. We therefore must thank Richard Willett, John Restorick, Terry Gant, Sean (I lift sluice gates early) Cooper, and Martin Koseikiewicz for their timely actions and observations.
The main points to draw from this are;
- Everyone keep a close eye on the weather and act early
- Be ready for the evil cocktail of high groundwater/wet ground/high tide
- Environment Agency Alerts and Warnings are excellent but local knowledge is also vital
- Pre-empt problems before they overwhelm you
- Flood plains work
- Note how reactive the Wey is in a very short stretch
Robert Turner
Chairman
Watery Lane 30th January 2021
