Tilshead Borehole Levels: 1st December 2022

The year rolls round once again and I know 1st December is eagerly awaited by at least one villager as it marks the start of the rather arbitrary “flood season” for the River Till.   I have been monitoring these for the last decade by recording the levels in the Tilshead borehole from where the water in the River Till ultimately comes.  Others with low-lying properties tend to get a little more interested later in the year, if the level creeps up towards 100 metres AOD (Above Ordnance Datum) when flooding of village properties becomes likely.

Those who read the Parish Magazine may have noticed a recent article about low rainfall levels measured in Berwick St James and a bit of speculation that water levels in the aquifer are low.  The reality is very different as shown in the following graph of water levels on the 1st of December of each year over the last decade.

So, 2022 begins with a water level of 80.93m AOD which is the fifth deepest over the last decade and only a smidgin below the 10-year average depth of 81.60.  Despite the dry summer, water levels in the aquifer held up well and that was clear by how late the river dried up.  This year it was late September and in some years over the last decade, it has dried up in early July.  We should expect nothing different from a winterbourne and the periods of flood and drought are what make the flora and fauna of our particular river system so unique.  More than that, the geography and topology of the River Till, coupled with its status as a winterbourne, give it international significance.

One final thought as this flood season gets underway, the highest water levels we have experienced in the River Till over the last decade were in winter 2013-2014; the first year we began monitoring in earnest.  The water level was 80.07m AOD on 1st December 2013 and stayed at that level, with a dry river bed at the south end of Church Street, until 23rd December when we recorded a slight rise.  One property had issues with hydrostatic water pressure over the Christmas period and by 8th January, other properties in the village were having problems with rising water.  Levels only really began to recede in April 2014.

Winterbourne Stoke Parish Council