Solent and South Downs water situation report: March 2024 summary
Updated 15 April 2024
Applies to England
© Crown copyright 2024
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1. Summary
Solent and South Downs (SSD) had above average rainfall in March, receiving 165% (110mm) of the long term average (LTA) rainfall (67mm). Monthly mean river flows ranged from above normal to exceptionally high and groundwater levels ranged from notably high to exceptionally high. Soils across SSD ended the month wetter than the average. 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 March, receiving 165% (110mm) of the LTA rainfall (67mm). There were 4 days (1, 4, 27 and 31) when the highest total was greater than 20mm. The gauge at Chiddingfold (Arun) recorded 26.8mm on 1 March which was the highest daily total in the month. During March there were no completely dry days.
Over the last year and a half the majority of monthly rainfall totals have been higher than average so there are some significant cumulative rainfall totals across SSD in the rainfall record that dates back to 1871.
Rainfall for the January 2024 to March 2024 period (3 month January to March) ranks as 4th wettest for SSD as a whole and the wettest on record for the East Hants Chalk, Test Chalk and West Sussex Chalk areal rainfall units.
For the October 2023 to March 2024 period (6 month October to March) SSD received 184% of the LTA which ranks as 2nd on wettest on record behind the October 2000 to March 2001 total. The totals for the Isle of Wight and Lymington areal units were the wettest on record.
For the April 2023 to March 2024 (12 month April to March) the SSD total ranks as 2nd on record (behind the April 2000 to March 2001 total) with the Lymington areal unit the wettest on record.
The 18 month period from October 2022 to March 2024 is the wettest on record for SSD and all the Hampshire and West Sussex areal units. For the East Sussex areal units October 1999 to March 2001 was the wettest 18 month period on record for an 18 month period starting in the month of October.
3. Soil moisture deficit and recharge
Soils across SSD ended the month wetter than the average for March, which means catchments are more responsive to run off.
4. River flows
Monthly mean river flows across SSD ranged from above normal to exceptionally high.
Flows were above normal:
- River Medina at Blackwater
Flows were notably high:
- River Lymington at Brockenhurst
Flows were exceptionally high:
- River Adur at Sakeham
- River Arun at Alfoldean
- River Cuckmere at Cowbeech
- River Itchen at Allbrook & Highbridge
- River Meon at Mislingford
- River Ouse at Goldbridge
- River Rother at Iping Mill
- River Test at Broadlands
- River Test at Chilbolton
- River Wallington at North Fareham
The monthly mean flows for March for the River Adur at Sakeham and for the River Arun at Alfoldean were the highest on record since 1967 and 1970 respectively. Flows were the second highest on record for the River Cuckmere at Cowbeech, the River Itchen at Allbrook & Highbridge, the River Test at Broadlands and the River Test at Chilbolton since 1968, 1958, 1957 and 1989 respectively.
5. Groundwater levels
End of month groundwater levels ranged from notably high to exceptionally high.
Groundwater levels were notably high at:
- Carisbrooke Castle (Isle of Wight)
- West Meon (East Hampshire Chalk)
Groundwater levels were exceptionally high at:
- Beeding Hill (West Sussex Chalk)
- Catherington (East Hampshire Chalk)
- Chilgrove (West Sussex Chalk)
- Clanville Gate (Test Chalk)
- Cornish Farm (East Sussex Chalk)
- Harting Common (Western Rother Greensand)
- Houndean Bottom (East Sussex Chalk)
- Lopcombe Corner (Test Chalk)
- Preston Candover (East Hampshire Chalk)
- Youngwoods Copse (Isle of Wight)
Groundwater levels for March were the second highest on record at Beeding Hill, Houndean Bottom, Lopcombe Corner and Youngwoods Copse and since 1979, 1977, 1963 and 1978 respectively.
6. Reservoir stocks
End of month reservoir stocks were above average at Ardingly Reservoir (Ouse) with 100% of total capacity (LTA 97%) and were below average at Arlington Reservoir (Cuckmere) with 86.9% of total capacity (LTA 99%).
7. Environmental impact
No licence restrictions were in force in March.
There were 29 Flood Alerts issued in SSD during March. 18 fluvial and 2 groundwater Flood Alerts in Hampshire and 9 fluvial Flood Alerts in Sussex.
There were 3 fluvial Flood Warnings issued in Hampshire during March.
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.