Research and analysis

Solent and South Downs water situation report: July 2025 summary

Updated 12 August 2025

Applies to England

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

1. Summary

Solent and South Downs (SSD) had average rainfall total in July, receiving 109% (60.1mm) of the long term average (LTA) of 55.3mm. Monthly mean river flows across SSD ranged from notably low to above 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 July. End of month reservoir stocks were below average at Ardingly Reservoir (Ouse) and at Arlington Reservoir (Cuckmere).

2. Rainfall

SSD had average rainfall total in July, receiving 109% (60.1mm) of LTA (55.3mm). The Ouse and the Pevensey Levels areal units on the east received the highest rainfalls during July. The Ouse areal unit received 137% (78.4mm) of LTA (57.4mm) and Pevensey Levels areal unit received 133% (75mm) of LTA (55mm). The Test Chalk and the Lymington areal units on the west received the lowest rainfall with 41.8mm for both areas. This represents 73% of LTA (57.5mm) for the Test Chalk and 82% of LTA (51.2mm) for the Lymington areal unit.

There were only six days with widespread rain: 5, 6, 18, 19, 20 and 31 July, and over 80 % of the month’s total rainfall fell on these days. The rest of July was mostly dry.

The wettest day was the 31 July, and the large rainfall totals recorded on this day boosted the monthly totals. The highest daily total of 53.0mm was recorded on 31 July at Warnford RG (East Hampshire Chalk). On the same day, 40.6mm was recorded at Cowes W WKS RG and 38.4mm at Calbourne RG both on the Isle of Wight.

The last 5 months has been the sixth driest March–July period on record for SSD. It was the third driest 5-month period on record for the Test Chalk areal unit, only the March-July period for 1976 and 1921 were drier. For the Sussex Coast it was the fourth driest 5-month period; only the March to July periods for 1976, 1921 and 1938 received less rainfall.

For longer time periods the running totals remains high. For the 24-month period (starting August 2023) it was the sixth highest total for SSD.

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 July.

4. River flows

Monthly mean river flows for July ranged from notably low to above normal across SSD.

Flows were notably low on the:

• River Lymington at Brockenhurst

Flows were below normal on the:

• River Meon at Mislingford
• River Arun at Alfoldean

Flows were normal on the:

• River Test at Broadlands
• River Test at Chilbolton
• River Itchen at Allbrook and Highbridge
• River Wallington at North Fareham
• River Medina at Blackwater
• River Rother at Iping Mill
• River Cuckmere at Cowbeech

Flows were above normal on the:

• River Adur at Sakeham
• River Ouse at Goldbridge

The notably low monthly mean flows for the River Lymington at Brockenhurst were the fifth lowest on record for July since 1960.

5.   Groundwater levels     

End of month groundwater levels for July 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:

• Harting Common (Western Rother Greensand)
• Catherington (East Hampshire Chalk)
• Chilgrove (West Sussex Chalk)
• Houndean Bottom (East Sussex Chalk)

Groundwater levels were normal at:

• Clanville Gate (Test Chalk)
• Lopcombe Corner (Test Chalk)
• West Meon (East Hampshire Chalk)
• Cornish Farm (East Sussex Chalk)

Groundwater levels were above normal at:

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

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

6. Reservoir stocks

End of month reservoir stocks were both below average. Ardingly Reservoir (Ouse) was at 51.71% of total capacity (LTA 82%) and Arlington Reservoir (Cuckmere) was at 66.1% of total capacity (LTA 73.35%).

7. Environmental impact 

7.1 Abstraction licence restriction

At the start of July there were 13 licence restrictions in force, which increased to 25 licence restrictions by the middle of the month. By the end of the month 20 licence restrictions were in place. These included:

Cessation of abstraction for:

• three licences on the Arun and one licence on the Loxwood Stream (Arun),
• one licences on the Pagham Rife (Sussex Coast)
• three licences on the River Rother and one licence on the River Lod (Western Rother Greensand)
• one on the River Meon (East Hampshire Chalk)
• four on the River Medina and three licences on the Shepherds Chine (Isle of Wight)
• one on the Lymington River and three on Walkford Brook (Lymington)
• one on the River Blackwater (Hampshire Tertiaries)

Restrictions on abstraction rates for:

• one on the River Meon (East Hampshire Chalk)
• one on the Calbourne (Isle of Wight)
• one on the River Blackwater (Hampshire Tertiaries)

7.2 Flood warnings in force

There were no flood warnings issued in July 2025, but eight fluvial flood alerts were issued. Six flood alerts were issued in East Sussex, one in West Sussex, and one in Hampshire.

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.