Tilshead Borehole Levels: 1st March 2020

A fascinating week in which to watch the water levels in the River Till and the Tilshead borehole.  At the start of the week, the Environment Agency was suggesting that the borehole level had peaked and was falling.  The reality, from their own borehole data, was quite the opposite and the level peaked at around 99.58m AOD overnight on Tuesday but never exceeded 99.57m at my fixed measuring time of 04:00.  The borehole level started to fall slowly on Thursday morning and now stands at 99.55m AOD.  With the heavy rain towards the end of the week, the borehole level may start to rise again in the next couple of days as the rain works through the system.  By contrast, the river continued to drop steadily throughout the week but shot up again to pretty close to its peak levels again yesterday.  The speed of the river’s response is another indication that the ground is pretty much saturated and additional rainwater is simply running off directly into watercourses.   The sharp-eyed amongst you may have spotted that the 29/02/2020 data isn’t shown on the graph, nor is data for earlier leap years.  That was a conscious decision taken when the records were started to avoid a data gap in three out of four years.

We are expecting some further rain overnight and into tomorrow; perhaps getting heavier in the afternoon.  The good news is that the forecast, that had been suggesting another week of moderate rain, is now much more optimistic with a few showers during the working week, but with further rain coming in for the weekend.   As we move further into March, it is possible that we will have a spell of more heavy rain or even snow before things settle down a little.  The second half of March may finally give us some relief from the rain and, at least for the moment, it looks like a period of dry, settled, and even warm weather.

The Environment Agency updated the ongoing Flood Warning yesterday (29/02/2020):

Groundwater flooding for the Till

Flooding is expected – immediate action required

The groundwater level in the Tilshead borehole now appears to have peaked at 99.5m AOD. We believe a possibility of flooding still exists for Tilshead, Orcheston, Shrewton, Winterborne Stoke, Berwick Saint James and Stapleford. Residents are still advised to ensure property resilience measures remain in place and that pumps are working where they have been installed. Flooding of roads and fields is possible. Residents may experience inundation of septic tanks and sewer systems. Further unsettled conditions and moderate rainfall is forecast by the Met Office throughout this weekend and into Tuesday 03/03/20, so we may expect levels in the borehole to start to rise slowly again.

Winterbourne Stoke Parish Council