Research and analysis

North West water situation: April 2024 summary

Updated 15 May 2024

Applies to England

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

1. Rainfall

April was another month where we observed the wet and unsettled weather that has been characteristic of the last 5 months. In particular, the first half of April saw exceptional rainfall, with indicator sites across the North West recording either close to, or above their long term averages (LTA) by the end of the first week. Although the second half of April saw drier weather with high pressure systems dominating, moderate rainfall totals were still recorded, particularly across Cumbria, and in the upland areas of Lancashire and Greater Manchester, Merseyside, and Cheshire (GMC).

Rainfall for North West England as a whole was classed as exceptionally high for April, at 195% of the LTA, and was ranked as the wettest April since 1871 (153 years), with a cumulative rainfall of 138mm, breaking the previous record of 130mm in 1913. Cumbria and Lancashire observed 203% of the LTA, classed as exceptionally high. This was also the wettest April for the area, with a cumulative rainfall of 153mm, breaking the previous record of 152mm in 1947. GMC observed lower totals at 168% of the LTA, but still classed as exceptionally high, and was ranked as the sixth wettest April since 1871.

Rainfall totals were generally higher towards the north of North West England, particularly in Cumbria, than towards the south, however, all hydrological areas were classed as exceptionally high with the exception of:

• the Douglas hydrological area (classed as notably high)
• the Esk (Dumfries) hydrological area (classed as above normal)

The highest rainfall (in terms of the LTA) was observed in the Eden hydrological area (232% of the LTA), classed as exceptionally high, and ranked as the second wettest April since 1871, and the wettest since 1947. The lowest rainfall was recorded in the Esk (Dumfries) hydrological area (147% of the LTA).

April 2024 was also ranked as the wettest April since 1871 for:

• the Esk (Cumbria) hydrological area, with a cumulative rainfall of 203mm, breaking the previous record of 182mm in 1947
• the Kent hydrological area, at 206mm, breaking the previous record of 182mm in 1970

April 2024 was also:

• the second wettest April since 1871 for the Derwent hydrological area;
• the fifth wettest April for the Cheshire Rivers Group, and the Wyre and Lune hydrological areas

The 3-month cumulative rainfall totals reflects the rainfall pattern seen in February, with nearly all hydrological areas classed as exceptionally high, with the exception of:

• the Eden hydrological area which was classed as notably high
• the Esk (Dumfries) hydrological area which was classed as above normal

The 3-month period ending in April was ranked as the wettest since 1871 for:

• North West England, with a cumulative rainfall of 400mm, breaking the previous record of 393mm in 2020
• GMC, which recorded 312mm during this period, breaking the previous record, which was 289mm in 1920
• the Esk (Cumbria) hydrological area, at 590mm, breaking the previous record of 561mm in 1989
• the Cheshire Rivers Group hydrological area, at 285mm, breaking the previous record of 266mm in 1920
• the Kent hydrological area, at 601mm, breaking the previous record of 588mm in 1989
• the Mersey and Irwell hydrological area, at 336mm, breaking the previous record of 323mm in 1970
• the Douglas hydrological area, at 319mm, breaking the previous record of 308mm in 1981

Of note, the 3-month period ending in April was also the second wettest 3-month period since 1871 for:

• Cumbria
• Lancashire
• the Derwent hydrological area
• the Wyre and Lune hydrological area

The 3-month period was also the third wettest for the Ribble hydrological area.

The 6-month cumulative rainfall totals see almost all hydrological areas across the North West England being classed as exceptionally high, with the exception of the Esk (Dumfries) hydrological area, which was classed as above normal.

The 6-month period ending in April was also the wettest since 1871 for:

• GMC at 697mm, breaking the previous record of 671mm in 2016
• the Cheshire Rivers Group hydrological area at 592mm, breaking the previous record of 533mm in 1920 by almost 60mm

In addition, this was the second wettest 6-month period since 1871 for:

• North West England
• Cumbria
• Lancashire
• the Esk (Cumbria) hydrological area
• the Derwent hydrological area
• the Eden hydrological area
• the Kent hydrological area
• the Mersey and Irwell hydrological area
• the Douglas hydrological area
• the Ribble hydrological area
• the Wyre and Lune hydrological area

The 12-month cumulative totals replicate the trend seen in the 6-month cumulative rainfall totals, with all hydrological areas, except for the Esk (Dumfries) which was classed as above normal, being classed as exceptionally high.

The 12-month period ending in April was the wettest since 1871 for:

• North West England with a cumulative rainfall of 1,676mm, breaking the previous record of 1,587mm in 2016
• Cumbria, at 1971mm breaking the previous record of 1,942mm in 2016
• GMC at 1,333mm, breaking the previous record of 1,229mm in 2020
• Lancashire at 1,784mm, breaking the previous record of 1,669mm in 1981 by over 100mm
• the Esk (Cumbria) hydrological area at 2,328mm, breaking the previous record of 2,262mm in 2016
• the Cheshire Rivers Group hydrological area at 1,169mm breaking the previous record of 1,074mm in 2001
• the Kent hydrological area at 2,463mm breaking the previous record of 2,261mm in 2016 by more than 200mm
• the Mersey and Irwell hydrological area at 1,479mm breaking the previous record of 1,381mm in 2020
• the Douglas hydrological area at 1,456mm breaking the previous record of 1,303mm in 2001 by over 150mm
• the Ribble hydrological area at 1,826mm breaking the previous record of 1,767mm in 2020
• the Wyre and Lune hydrological area which at 1,960mm also broke the previous record which was 1,876mm in 2016

Additionally, the 12-month period ending in April was also:

• the second wettest on record for the Eden hydrological area
• the third wettest on record for the Derwent hydrological area

2. Soil moisture deficit and recharge

Drier weather observed during the second half of April increased soil moisture deficits (SMD) across the North West compared to levels at the end of March. This is particularly the case for Lancashire and GMC. SMD levels for the end of April across North West England fell within the range of 1 to 24mm. This was either at or slightly higher than expected for the time of year.

3. River flows

Monthly mean river flows increased across all catchments in response to the rainfall received during April. River flows in all catchments increased to levels that far exceeded what would be expected for the time of the year. Overall, 20 out of 25 sites were classed as exceptionally high, with the remaining sites classed as notably high. It is also worth noting that 18 out of 25 of the indicator sites recorded monthly mean river flows above 200% of their LTA. 

Monthly mean river flows were generally higher in Cumbria, Cheshire, and in the uplands of Lancashire and Greater Manchester than elsewhere, which reflects the rainfall that was received during the month. River flows were highest (in terms of percentage of the LTA) in the Upper Lune catchment at Lunes Bridge (301% of the LTA, classed as exceptionally high), and lowest in the Tame catchment at Portwood (164% of the LTA, classed as notably high).

There were some notable peaks in daily mean flow recorded when rain fell on saturated ground on 8 and 9 April. Daily mean flows above Q1 (this is where mean flow has been exceeded only one percent of the time during the lifespan of the gauging station) were recorded at:

• Ashbrook gauging station on the River Weaver
• Bollington Mill gauging station on the River Bollin
• Bulgill gauging station on the River Ellen
• Sheepmount gauging station on the River Eden
• Kirkby gauging station on the River Alt

4. Groundwater levels   

Groundwater levels across the North West at the end of April were classed between exceptionally high and normal. Groundwater levels at Skirwith increased from notably high to exceptionally high, and decreased at Bruntwood Hall from exceptionally high to notably high.

All other groundwater indicator sites remained at the same classification with:

• Lea Lane being classed as normal
• Brown Bank Lay-By being classed as above normal
• Richmond Park and Priors Heyes being classed as exceptionally high

Levels at Priors Heyes remain high compared to historic levels because the aquifer is recovering from the effects of historically high abstractions.

5. Reservoir storage

Total reservoir storage for North West England decreased slightly from 93% at the end of March to 92% at the end of April, higher than the average of 90% at this time of the year, but slightly lower than this time last year when total reservoir storage was at 93%.

At the end of April, reservoir storage (in terms of percentage) was highest at Crummock Water and Ennerdale Water, which were both at 100% full. Storage was lowest at Longdendale (78%). The combined storage at Haweswater and Thirlmere was 96%, higher than the average of 87% at this time of year, and higher than the storage level this time last year which was 94%.

Reservoirs kept low for maintenance works include:

• Audenshaw No.1, Torside, and Woodhead (part of the Longdendale system)
• Anglezarke, and High Bullough (part of the Rivington system)
• Dingle, and Jumbles (part of the Bolton supply system)
• Harlock (part of the Poaka Beck system)
• Kitcliffe (part of the Piethorne Valley system)
• Ogden Lower, and Ogden Upper (part of the Ogden (Barley) system)
• Alston No.2 (part of the Longridge system)
• Llyn Celyn (part of the Dee (Celyn and Brenig) system)
• Coldwell Upper (part of the Coldwell system)
• Cragg (part of the Cowpe system),
• Ridegate (part of the Ridegate system)

Author: Cumbria and Lancashire Hydrology Team, hydrology.CMBLNC@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 herein.