Research and analysis

Solent and South Downs water situation report: June 2025 summary

Updated 15 July 2025

Applies to England

• Publication for Northern Ireland
• Publication for Scotland
• Publication for Wales

1. Summary

Solent and South Downs (SSD) had below average rainfall in June, receiving 65% (36mm) of the long term average (LTA) of 56mm. Monthly mean river flows across SSD ranged from exceptionally low to normal. The end of month groundwater levels ranged from exceptionally low to above normal. Soils across SSD ended the month much drier than the average for June. End of month reservoir stocks were below average at Ardingly Reservoir (Ouse) and at Arlington Reservoir (Cuckmere).

2. Rainfall

SSD had below average rainfall in June, receiving 65% (36mm) of LTA (56mm). The rainfall distribution shows slightly lower totals in the east when compared to the rest of the area. The Lymington areal unit received the most rainfall during June with 82% (45mm) of LTA (55mm). The lowest monthly rainfall totals were recorded in the Pevensey Levels areal unit with 25mm, representing 49% of LTA (52mm). This was followed closely by the East Sussex Chalk with 28mm representing 50% of LTA (56mm). 

The highest daily totals of 27mm and 25mm were recorded on 6 June at Peel Common (Hampshire Tertiaries) and at Buxted (Ouse) respectively. These totals represent 50% of the total rainfall for the month at both sites.

There were only 10 wet days this month. The majority of these were in the first week of the month between the 1 and 8 June. However, 80% of the total monthly rainfall fell over just 3 days, between 5 and 7 June. The rest of June was mostly dry with light scattered rain, though temperatures were high.

June’s rainfall has not been notable, but the last 4 months of rainfall has been the fourth driest March to June period on record for SSD. It was the third driest March to June period on record for the Test Chalk, Adur and Arun areal units. It was the fourth driest of that period for the remainder of the SSD areal unit.

All these statistics are based on records going back to 1871.

3. Soil moisture deficit and recharge

Soils across SSD ended the month much drier than the LTA for June.

4. River flows

Monthly mean river flows for June ranged from exceptionally low to normal across SSD.

Flows were exceptionally low on the River Arun at Alfoldean.

Flows were below normal on the:

• River Lymington at Brockenhurst
• River Test at Broadlands
• River Meon at Mislingford

Flows were normal on the:

• River Rother at Iping Mill
• River Adur at Sakeham
• River Ouse at Goldbridge
• River Cuckmere at Cowbeech
• River Wallington at North Fareham
• River Medina at Blackwater
• River Itchen at Allbrook and Highbridge
• River Test at Chilbolton

The exceptionally low monthly mean flows for the River Arun at Alfoldean were the third lowest on record (1970) for June.

5. Groundwater levels 

End of month groundwater levels for June ranged from exceptionally low to above normal across SSD.

Groundwater levels were exceptionally low at:

• Carisbrooke Castle (Isle of Wight)
• Beeding Hill (West Sussex Chalk)

Groundwater levels were below normal at:

• Houndean Bottom (East Sussex Chalk)
• Catherington (East Hampshire Chalk)
• Chilgrove (West Sussex Chalk)

Groundwater levels were normal at:

• Lopcombe Corner (Test Chalk)
• Clanville Gate (Test Chalk)
• West Meon (East Hampshire Chalk)
• Harting Common (Western Rother Greensand)
• Cornish Farm (East Sussex Chalk)

Groundwater levels were notably high at:

• Preston Candover (East Hampshire Chalk)
• Youngwoods Copse (Isle of Wight)

The exceptionally low groundwater level at Carisbrooke Castle (Isle of Wight) is a record breaking lowest June level since 1977. Beeding Hill (West Sussex Chalk) is also the second lowest June level on it record that dates back to 1979.

6. Reservoir stocks

End of month reservoir stocks were below average at Ardingly Reservoir (Ouse) and at Arlington Reservoir (Cuckmere).

Ardingly Reservoir (Ouse) was at 74.4% of total capacity (LTA 91.0%) and Arlington Reservoir (Cuckmere) was at 76.3% of total capacity (LTA 84.0%).

7. Environmental impact 

7.1 Abstraction licence restriction

At the start of June there were 6 licence restrictions in force. By then end of the month 14 licence restrictions were in place, including the following.

Cessation of abstraction for:

• 3 licences on the Arun (Arun)
• one licence on the Loxwood Stream (Arun)
• one licence on the River Lod (Western Rother Greensand)
• one on the River Meon (East Hampshire Chalk)
• 3 on Walkford Brook (Lymington)
• one on the Lymington River (Lymington)

Restrictions on abstraction rates for:

• one licence on the Pagham Rife (Sussex Coast)
• one on the Wallers Haven (Pevensey Levels)
• one on the River Blackwater (Hampshire Tertiaries)

7.2 Flood Warnings in Force

There were no flood warnings issued in June 2025, but 2 fluvial flood alerts were issued. The 2 flood alerts were both in East Sussex, one on the Hollington Stream, and the other at Polegate and Wannock.

Author: HydrologySSD@environment-agency.gov.uk

All data are provisional and may be subject to revision. The views expressed in this document are not necessarily those of the Environment Agency. Its officers, servants or agents accept no liability for any loss or damage arising from the interpretation or use of the information, or reliance upon views contained in this report.