Solent and South Downs water situation report: November 2024 summary
Updated 13 December 2024
Applies to England
© Crown copyright 2024
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1. Summary
Solent and South Downs (SSD) had average rainfall in November, receiving 102% (91mm) of the LTA (89.6mm). Monthly mean river flows across SSD ranged from normal to notably high. End of month groundwater levels ranged from normal to exceptionally high. Soils across SSD ended the month wetter than the average for November. End of month reservoir stock was above average at Ardingly Reservoir (Ouse) and was below average at Arlington Reservoir (Cuckmere).
2. Rainfall
SSD had average rainfall in November, receiving 102% (91mm) of the LTA (89.6mm). The areal units in Hampshire received higher rainfall, than those in Sussex. The Pevensey Levels areal unit received the lowest rainfall with 76% (72mm) of LTA. The Test Chalk areal unit in the west of SSD received the highest rainfall with 140% (112mm) of LTA.
Between the 17 and 26 November, there were 2 named storms - Bert and Conall. About 95% of the rainfall in November fell in these 10 consecutive days. The rest of the month was mostly dry, except the 30 November which was a wet day.
Over 30% of the rainfall fell on 26 November, when the highest daily rainfall totals of the month were recorded:
- 45.7mm at Calbourne RG (Isle of Wight)
- 40.9mm at Chilgrove House RG (West Sussex Chalk)
- 40.8mm at Chiddingfold RG (Arun)
- 40.5mm at Duncton RG (Western Rother Greensand)
- 40.1mm at Carisbrooke RG (Isle of Wight)
For Test Chalk areal unit, the current year to date, last 11 months (January to November), was the wettest on record. Also, the last 3-months period, September to November, was the second wettest on record for Test Chalk areal unit.
Over the longer time periods, the 14-month, 18-month and 24-month running totals remain exceptionally high and were the wettest on record for SSD. These periods were also the wettest for the following areal units:
- Test Chalk
- East Hampshire Chalk
- West Sussex Chalk
- Isle of Wight
- Hampshire Tertiaries
- Lymington
- Sussex Coast
All these statistics are based on records going back to 1871.
3. Soil moisture deficit and recharge
Soils across SSD ended the month wetter (0mm) than the average for November (25mm).
4. River flows
Monthly mean river flows across SSD ranged from normal to notably high.
Flows were normal on the:
- River Meon at Mislingford
- River Wallington at North Fareham
- River Arun at Alfoldean
- River Ouse at Goldbridge
- River Cuckmere at Cowbeech
Flows were above normal on the:
- River Lymington at Brockenhurst
- River Medina at Blackwater
- River Rother at Iping Mill
- River Adur at Sakeham
Flows were notably high on the:
- River Test at Chilbolton
- River Test at Broadlands
- River Itchen at Allbrook and Highbridge
The monthly mean flows for November for the River Test were the fifth highest on record at Chilbolton (1989), and the sixth highest at Broadlands (1958).
5. Groundwater levels
End of month groundwater levels for November ranged from normal to exceptionally high.
Groundwater levels were normal at:
- Catherington (East Hampshire Chalk)
- Harting Common (Western Rother Greensand)
- Chilgrove (West Sussex Chalk)
- Beeding Hill (West Sussex Chalk)
Groundwater levels were above normal at:
- Carisbrooke Castle (Isle of Wight)
- West Meon (East Hampshire Chalk)
- Houndean Bottom (East Sussex Chalk)
Groundwater levels were notably high at:
- Lopcombe Corner (Test Chalk)
- Cornish Farm (East Sussex Chalk)
Groundwater levels were exceptionally high at:
- Clanville Gate (Test Chalk)
- Preston Candover (East Hampshire Chalk)
- Youngwoods Copse (Isle of Wight)
Groundwater levels for November were the highest on record at Youngwoods Copse (1978), second highest at Preston Candover (1975) and third highest at Clanville Gate (1966).
6. Reservoir stocks
End of month reservoir stocks was above average at Ardingly Reservoir (Ouse) and was below average at Arlington Reservoir (Cuckmere). Ardingly Reservoir (Ouse) was at 100% of total capacity (LTA 77%) and Arlington Reservoir (Cuckmere) was at 57.2% of total capacity (LTA 72.36%).
7. Environmental impact
During November there were a total of 5 licence restrictions in force, 4 cessations and one reduced abstraction rate.
The cessations were in force on the:
- River Rother (Arun and Western Streams)
- River Lymington (New Forest)
- River Hamble (East Hants)
- River Ouse (Adur and Ouse)
The reduced abstraction rate was in force on the River Meon (East Hampshire).
During November there were 29 Flood Alerts issued. In Hampshire 13, on the Isle of Wight 4, and in Sussex 12 Flood Alerts; all fluvial.
During November there were 13 Flood Warnings issued. In Hampshire 6, on the Isle of Wight 2 and in Sussex 5 Flood Warnings; all fluvial.
Author: [email protected]
Contact Details: 03708 506506
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.