8/14/2019 Solent and South Downs Groundwater Update

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Solent and South Downs Groundwater UpdateBriefing Note No 222 January 2010

Groundwater Prospects

Groundwater levels are currently around the long term average for the time of yearacross much of the Northern and Western Hampshire. However, above averagelevels are present in East Hampshire and parts of West Sussex. Groundwaterlevels are expected to continue to rise following continuing winter rain.

In the Somborne Valley and Hursley area, groundwater levels are high and havecontinued to rise steadily in the past few weeks. Our records suggest that there isthe possibility of cellar flooding at Kings Somborne at the current groundwaterlevel (32.2m Above Ordnance Datum).

Groundwater levels are currently also high at the following locations:

Broadhalfpenny Down borehole which gives indicative levels forHambledon, Denmead, Meonstoke and Soberton

Chalton borehole which gives indicative levels for Finchdean, DeanlaneEnd and Rowlands Castle.

At these locations groundwater levels have risen further in the last month, but arenow stabilising. At the current high groundwater levels (around 56.5 m AboveOrdnance Datum) cellar and external flooding in these villages are possible. In thisarea groundwater levels respond fairly rapidly to rainfall so any heavy rainfall willcause the levels to rise again.

In West Sussex groundwater levels in the River Lavant catchment are also high,which has resulted in the Lavant flowing at Charlton and East Dean.

Prospects for the coming weeks

The weather outlook is for further unsettled weather, although temperatures willrecover to seasonal averages. As catchments are saturated, further rainfall willcause an increase in groundwater levels. In most years, levels peak in late Marchand April but this is dependent on the rainfall we receive in the coming weeks.

8/14/2019 Solent and South Downs Groundwater Update

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