Groundwater

The Pillhill Brook Association (PBA) monitors groundwater behaviour within our catchment on a weekly basis. Groundwater level is important because it dictates the height of water in the brook and hence flow and also how quickly rainfall will soak away into the ground, preventing flooding. We monitor levels at 5 local boreholes

See map below for locations.

Current groundwater situation in the Pillhill Brook Catchment

The EA's groundwater trigger point of 84 m above sea level was exceeded at Clanville Gate on 21 October 2024. 

Groundwater at Clanville Gate exceeded 86 m above sea level on 1 December 2024 and the Environmental Agency are now issuing regular briefings on groundwater flooding. 

Groundwater at Clanville Gate exceeded 89 m above sea level on 2 February and is continuing to rise in response to the 145 mm of rainfall that fell in month of January. However groundwater levels remain lower than this time last year no doubt due in part to a 50% reduction in rainfall during the last 3 months of the year - 250 mm in Q424 versus 486 mm in Q423.

The latest Groundwater Flood alert for the villages surrounding Andover was issued on 10 February - read that here or sign up to receive your own EA Flood Warnings here.

Pillhill Brook Catchment GW Levels w/e 07.02.25.pdf

Historic Groundwater Story

The last Groundwater situation for Hampshire in 2024 was issued on 6 June 2024. 

The Environmental Agency (EA) use the groundwater level at Clanville Gate to inform them of the risk of flooding in the villages surrounding Andover. The EA also use a groundwater level of 84 m above sea level as the trigger point with Southern Water for the risk of major groundwater infiltration in the sewer network. Click on Andover Villages (Clanville) for the latest groundwater data. 

The last flood alert in 2024 was removed on Tuesday 28 May 2024 with a groundwater level at Clanville Gate of 89.27 m.