Research and analysis

Solent and South Downs water situation report: January 2026 summary

Updated 17 February 2026

Applies to England

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

1. Summary

Solent and South Downs (SSD) had above average rainfall in January. SSD received 193% (186mm) of long term average (LTA) of 96.8mm. Monthly mean river flows and end of month groundwater levels for January ranged from normal to exceptionally high across SSD. Soils ended the month wetter than the average for January across SSD. End of month reservoir stocks were above average at Ardingly Reservoir (Ouse) and below average at Arlington Reservoir (Cuckmere).

2. Rainfall

SSD had above average rainfall in January, receiving 193% (186mm) of LTA (96.8mm). All areal rainfall units in SSD had exceptionally high rainfall totals in January, except the Pevensey Levels unit, which was in the notably high range.

The Adur areal unit received the highest monthly rainfall total with 216% (204.3mm) of LTA (94.7mm). The Test Chalk, East Hampshire Chalk, Hampshire Tertiaries, Lymington and Arun areal units also received over 200% of LTA, with rainfall between 188mm and 207mm.

The Sussex Coast, East Sussex Chalk, Ouse, Cuckmere, and Pevensey Levels hydrological areal units in southeast part of SSD received the lower rainfall totals. Nevertheless, even these units had rainfall between 151mm and 182mm and counted for 168% to 185% of LTA. The Cuckmere and the Pevensey Levels areal units received the lowest rainfall totals with 168% (159mm) of LTA (94.4mm) and 169% (151mm) of LTA (89.5mm).

Over half of the monthly rainfall total was recorded on the 5 wettest days of the month: 8, 15, 20, 21 and 26 January. Storm Chandra swept across the UK from 26 to 27 January and brought a spell of severe weather with strong winds and persistent heavy rainfall. The highest daily totals were all recorded on 26 January with 43mm at Lyndhurst RG (Lymington) and 40mm at Testwood RG (Hampshire Tertiaries).

It has been the second wettest January on record for SSD and also for the areal units:

• Test Chalk,
• East Hampshire Chalk
• Hampshire Tertiaries
• West Sussex Chalk
• Western Rother Greensand
• Arun
• Adur

The January rainfall totals in the remaining 7 areal units in SSD ranked in the top 10 wettest on record.

November to January rainfall and August to January rainfall rank as fifth wettest on record for the Adur areal unit and 10th wettest for Lymington.

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

3.   Soil moisture deficit and recharge

Soil moisture deficits have fallen across the SSD in response to the exceptionally high rainfall. Soils across SSD ended the month wetter than the LTA for January and all areal units are no longer in deficit.

4. River flows

Monthly mean river flows for January ranged from normal to exceptionally high across SSD.

Flows were normal on the:

• River Test at Chilbolton

Flows were above normal on the:

• River Test at Broadlands
• River Itchen at Allbrook and Highbridge
• River Meon at Mislingford
• River Wallington at North Fareham
• River Medina at Blackwater

Flows were notably high on the:

• River Cuckmere at Cowbeech

Flows were exceptionally high on the:

• River Lymington at Brockenhurst
• River Rother at Iping Mill
• River Arun at Alfoldean
• River Adur at Sakeham
• River Ouse at Goldbridge

The monthly mean flows for January were:

• highest on record for the River Adur at Sakeham (1967)
• second highest on record for the River Arun at Alfoldean (1970) and the River Lymington at Brockenhurst (1960)
• third highest for the River Ouse at Gold Bridge (1960)
• fourth highest for the River Rother at Iping Mill (1966)
• fifth highest for the River Cuckmere at Cowbeech (1968)

5. Groundwater levels     

End of month groundwater levels for January ranged from normal to exceptionally high.

Groundwater levels were normal at:

• Clanville Gate (Test Chalk)
• Youngwoods Copse (Isle of Wight)
• Catherington (East Hampshire Chalk)
• Harting Common (Western Rother Greensand)
• Cornish Farm (East Sussex Chalk)

Groundwater levels were above normal at:

• Lopcombe Corner (Test Chalk)
• Preston Candover (East Hampshire Chalk)
• West Meon (East Hampshire Chalk)

Groundwater levels were notably high at:

• Carisbrooke Castle (Isle of Wight)
• Houndean Bottom (East Sussex Chalk)

Groundwater levels were exceptionally high at:

• Chilgrove (West Sussex Chalk)
• Beeding Hill (West Sussex Chalk)

The exceptionally high groundwater levels for January were the highest on record at Beeding Hill since 1979, and seventh highest at Chilgrove since 1836. The notably high levels for January were the third highest at Carisbrooke Castle since 1977, and fifth highest at Houndean Bottom since 1977.

6. Reservoir stocks

End of month reservoir stocks were above average at Ardingly Reservoir (Ouse) and below average at Arlington Reservoir (Cuckmere). Ardingly Reservoir was at 100% of total capacity (LTA 93%), and Arlington Reservoir was at 83% of total capacity (LTA 95.4%).

7. Environmental impact 

7.1 Abstraction licence restriction

At the start of January there were 6 licence restrictions in force, which increased to 7 licence restrictions in the second week, but by the end of the month there were no licence restrictions in place. Over the month the restrictions included, one:

• public water supply (PWS) licence on the River Ems
• PWS licence on the Ouse under drought order conditions
• licence on the Western Rother
• licences on the River Meon,
• licence on the River Hamble
• licence on the River Wallington
• licence on the Sowley Stream

7.2 Flood Alerts and Warnings in Force

Flood Alerts were issued over most of SSD between 8 to 31 January (based on date of first issue).

Fluvial flood alerts were issued for 34 individual areas and some repeatedly, so that 72 fluvial flood alerts for were issued. At the end of the month, 14 flood alerts were still in place.

Seven groundwater flood alerts issued in January starting on 26 January and all were in place at the end of the month.

Between 9 January to 28 January 35 fluvial flood warnings were issued for 24 individual areas. Most of the warnings, 22, were issued on 27 January in response to Storm Chandra. Two warnings were still in place at the end of the month.

Author: HydrologySSD@Environment-agency.gov.uk

Contact Details: 03708 506 506

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.