Research and analysis

Solent and South Downs water situation report: July 2026 summary

Updated 12 August 2026

Applies to England

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

1. Summary

Solent and South Downs (SSD) had well below average rainfall in July, receiving 1% (0.7mm) of long term average (LTA) of 55.3mm. Monthly mean river flows decreased in July at all indicator sites across SSD, and ranged from exceptionally low to normal. Groundwater levels at all sites continue to recede and ranged from notably low to above normal in July. Soils in all the hydrological areas ended the month drier than average for July. End of month reservoir stocks decreased and were below average at Ardingly Reservoir (Ouse) and at Arlington Reservoir (Cuckmere).

2. Rainfall

SSD had well below average rainfall in July, receiving 1% (0.7mm) of the LTA (55.3mm). The lack of rain affected all hydrological areas. East Sussex Chalk areal unit, which received the most rainfall in July, recorded 1.5mm rain; this represents 3% of LTA (57.3mm). The Isle of Wight and the Sussex Coast areal units received the lowest rainfall with only 0.1mm for the whole month, which is less than 1% of the LTA.

In July there were only 5 wet days, when 1 mm or more of precipitation was recorded at specific rain gauges. These days were 2, 4, 25, 26 and 30 July. The highest daily rainfall totals were recorded at below locations, but even these were below 2mm:

• 1.9mm was recorded at Hastings Newgate, in the Pevensey Levels hydrological area on 26 July
• 1.9mm was recorded at Middle Wallop, west of Winchester, in the Test Chalk hydrological area, on 30 July

For the East Sussex Chalk hydrological area, the monthly rainfall total was the second lowest on record. In the rest of the hydrological areas, the July monthly rainfall totals were the lowest on record. For the SSD as a whole, the July rainfall total was the lowest on record.

The April to July 4-month period has been the fifth driest for the Test Chalk and for the East Sussex Chalk areal unit. It was also the eight driest on record for the East Hampshire Chalk areal unit and the West Sussex Chalk areal unit.

The March to July 5-month period has been the third driest for the Cuckmere and for the Pevensey Levels areal unit. It was also the fourth driest on record for the Sussex Coast areal unit and the fifth driest for the Ouse areal unit.

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

3. Soil moisture deficit and recharge

Soils in all the hydrological areas ended the month drier than average for July due to the lack of rainfall. Soil moisture deficits (SMDs) continue to rise and are higher than the LTA for the end of July for SSD. On 31 July SMD ranged between 159mm and 173mm in the hydrological areas which is well above the LTA of 80mm to 94mm. The combination of very high SMDs and very low rainfall resulted in no recharge across the SSD area.

4. River flows

Monthly mean river flows decreased at all indicator sites across SSD, and ranged from exceptionally low to normal in July.

Flows at three sites were classed exceptionally low: on the River Lymington at the Brockenhurst, on the River Wallington at North Fareham and on the River Arun at Alfoldean. These rivers are in predominantly clay catchments with little groundwater input and the flows ranged between 11% and 32% of the LTA. 

Flows at three sites were classed below normal: on the River Test at Broadlands, on the River Adur at Sakeham and the on River Cuckmere at Cowbeech. The flows at these sites ranged between 41% and 76% of the LTA. 

Flows at the rest of the indicator sites were classed as normal and ranged between 85% and 95% of the LTA. Flows were normal on the River Test at Chilbolton, on the Itchen at Allbrook and Highbridge, on the Meon at Mislingford, on the Medina at Blackwater and on the Rother at Iping Mill. These sites are in predominantly groundwater fed catchments, which means rivers are gaining water from the underlying geology. Flows were also classed as normal on the Ouse at Goldbridge, at this site the augmentation and compensation water releases from the Ardingly reservoir impact flows.

The monthly mean flows for July were the second lowest on record for the River Arun at Alfoldean since 1970. Flows were the third lowest for July for the Wallington at North Fareham and the Lymington at the Brockenhurst, in a record going back to 1976 and 1960, respectively.

5. Groundwater levels     

End of month groundwater levels for July ranged from notably low to above normal.

Groundwater levels at all sites continue to recede in line with the expected trend for this time of the year. However, reflecting the legacy of the high winter storage, groundwater levels remained healthy at the majority of the indictor sites, despite the dry weather over the recent months.

The majority of the report sites ended July with groundwater levels categorised as normal.

End of month groundwater levels were above normal at Preston Candover (East Hampshire Chalk) and at Youngwoods Copse (Isle of Wight).

End of month groundwater levels were below normal at Carisbrooke Castle (Isle of Wight), at Chilgrove (West Sussex Chalk) and at Houndean Bottom (East Sussex Chalk). End of month groundwater level was notably low at Beeding Hill (West Sussex Chalk).

The groundwater levels were the ninth lowest on record for July at Carisbrooke Castle (Isle of Wight), at Harting Common (Western Rother Greensand), at Beeding Hill (West Sussex Chalk) and at Houndean Bottom (East Sussex Chalk) since 1977, 1984, 1979 and 1977, respectively.

6. Reservoir stocks

End of month reservoir stocks decreased and were below average at Ardingly Reservoir (Ouse) and at Arlington Reservoir (Cuckmere). Ardingly Reservoir (Ouse) was at 61.22% of total capacity (LTA 82%) and Arlington Reservoir (Cuckmere) was at 61.4% of total capacity (LTA 73.35%).

7. Environmental impact 

At the beginning July, there were 12 licence restrictions in place, and by the end of the month the number of restrictions increased to 20.

For more information see the full report.

Arun & Western Streams:

• at the beginning of the month there were 3 restrictions in place: one on the River Lod, one on the Western Rother, and one on the River Arun
• from the second week 3 additional hands off flow (HoF) were triggered, 2 on the River Arun, and one on the Pagham Rife

All 6 restrictions were in place at the end of the month.

Cuckmere & Pevensey Levels:

• at the beginning of the month there was a restriction in place on abstraction rates for one Public Water Supply (PWS) licence on the Wallers Haven
• from the second week of July new condition triggered for a PWS on the River Cuckmere

Both were in place at the end of the month.

East Hampshire:

• there was one HoF in place throughout the month for a licence on the River Meon

Isle of Wight:

• at the beginning of July there were 2 HoFs in place, both on the River Medina. The PWS Media-Yar transfer scheme is in operation since 23 June
• from the second week of July 3 additional HoFs were triggered on the River Medina

All 5 restrictions and the transfer scheme were in place at the end of the month.

New Forest:

• there were four HoFs in place throughout the month, 3 on the Walkford Brook and one on the River Lymington

Test and Itchen:

• there was no restriction in place in the first part of July
• from the last week of July there was a new reduced abstraction rate condition triggered on the river Test

No flood alerts or flood warnings were issued in July.

Author: Groundwater, Hydrology and Contaminated Land Team, Solent and South Downs Area

Contact Details: 03708 506 506, 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.