Monthly Water Situation Report North West England

Home , Audenshaw (ward), Cheshire, Cheshire (South), Haweswater Reservoir, Lancashire, Lancashire (North)

Summary – August 2021

Table 1. North West England summary of the current water situation. Parameter Current status Rainfall North West England rainfall was 74% of the August Long Term Average (LTA). Classed as ‘Below normal’ this month. Soil Moisture Deficit (SMD) By the end of August, SMD levels had decreased across the majority of North West England compared to levels at the start of August. River Flows Classed between ‘Below normal’ and ‘Above normal’. Groundwater Levels Classed between ‘Normal’ and ‘Exceptionally high’. Reservoir Storage Total North West England reservoir storage decreased from 68% (start of August) to 66% (end of August).

Rainfall Rainfall for North West England as a whole was classed as ‘Below normal’ for August (74% of the LTA). The 1-month August rainfall totals across the hydrological areas, indicated that six out of ten areas observed monthly rainfall totals classed as ‘Below normal’, with monthly totals for the remaining four hydrological areas classed as ‘Normal’ (Figure 2). The highest rainfall in August (in terms of percentage of the LTA) was observed in the Mersey and Irwell (91% of the LTA for August, classed as ‘Normal’), with the lowest rainfall being observed in the Wyre and Lune (64% of the LTA, classed as ‘Below normal’) (Figure 3). The first half of August brought the majority of the monthly rainfall total, with the rainfall during the remaining half of August was largely very dry and settled. The 3-month cumulative rainfall totals, between June and August, indicated ‘Exceptionally low’ rainfall across all hydrological areas within Cumbria. In particular, the Esk (Cumbria) and Derwent were ranked as the 4th driest, 3-month cumulative rainfall period (June to August) in 131 years. Notably, the Esk (Dumfries), Eden and Kent which were also ranked 5th driest, 6th driest and 6th driest respectively, for the same period of analysis. The 6-month cumulative rainfall totals (March to August) also indicated that the Esk (Dumfries) was classed as ‘Exceptionally low’ and the 2nd driest in 131 years. However, for North West England there was ‘Exceptionally high’ rainfall in May, which was 176% of the May long term average. This resulted in ‘Normal’ to ‘Exceptionally high’ river flows, helping to refill the reservoirs. The inclusion of May’s rainfall, which ranged between 156% to 202% of the LTA for May across the hydrological areas (with the exception of the Esk Dumfries) and was classed between ‘Notably high’ and ‘Exceptionally high’ across those areas, resulted in the 4-month cumulative total being classed as between ‘Below normal’ and ‘Above normal’, which is similar to classification of the 6-month cumulative period.

Soil Moisture Deficit/Recharge In general, the SMD levels decreased during August across most areas of the North West (Figure 4), with the exception of parts of the Weaver catchment in Greater Manchester, Merseyside and Cheshire (GMC) and the coastal areas around Morecambe Bay. In almost all catchments, SMD remains higher than expected for this time of year. Higher SMDs, between 101-130mm, were observed in the parts of GMC.

River Flows Despite the lower monthly rainfall totals in August compared to July, monthly mean flows increased in all catchments in the North West, with only flows in the Weaver catchment decreased from the previous month. This may be attributed to several short-lived intense rainfall events earlier in the month, particularly in the period between the 6th and 9th August, which may have skewed the monthly mean flow. River flows were classed between ‘Below normal’ and ‘Above normal’ in comparison to the LTA for August (Figure 5), with the highest flows (in terms of percentage of the LTA) in both the Mersey and Weaver catchments (114% of LTA, classed as ‘Above normal’) and lowest in the Lune (37% of LTA, classed as ‘Below Normal’) (Figure 6). At the end of August, four gauging stations across the North

All data are provisional and may be subject to revision. The views expressed in this document are not necessarily those of the AllEnvironment data are provisional Agency. Its and officers, may be servants subject orto agentsrevision. accept The viewsno liability expressed for any in lossthis ordocument damage arearising not necessarilyfrom the interpretati those of tonhe or Environmentuse of the information, Agency. Its or officers, reliance servants upon views or agents contained accept herein. no liability © Environmentfor any loss or damageAgency arising 2014 from the interpretation or use of the information, or reliance upon views contained herein.

West (three of which are in Cumbria and Lancashire) were at or below Q95 flow (a Q95 flow is the flow equalled or exceeded 95% of the time within the period of record and is an indicator of low flows).

Groundwater Levels Between the end of July and the end of August, groundwater levels have fallen, however have remained classed between ‘Normal’ and ‘Exceptionally high’ (Figure 7). The only changes to the banding classes since last month have occurred at Bruntwood Hall and Skirwith. For August, Crow Lady Farm was classed as ‘Normal’, Bruntwood Hall classed as ‘Above normal’ and Skirwith classed as ‘Notably high’. Brown Bank Lay-By, Richmond Park and Priors Heyes were all classed as ‘Exceptionally high’. The levels at Priors Heyes remained high compared to historic levels because the aquifer is recovering from the effects of historically high abstractions.

Reservoir Storage/Water Resource Zone Stocks Reservoir stocks for North West England decreased from 68% at the end of July, to 66% by the end of August (Figure 10). At the end of August, reservoir stock (in terms of percentage) was highest at Crummock (100%) and lowest at Haweswater (43%). Notably, reservoir stocks in the Lakes Group was 49% at the end of August (Figure 1). The combined storage at Haweswater and Thirlmere was below average for the time of year (46% compared to an average of 71%) and 33% lower than this time last year. Audenshaw No.1 and High Bullough were among the reservoirs kept low for maintenance works.

Haweswater Reservoir

Level 1 Level 2 Level 3 Enhanced monitoring and operations 100

Percentage of live Percentage ofcapacity live 10

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 1: Storage in Haweswater reservoir including the drought levels for the reservoir and storage for representative years; 1995, 2003, 2010, 2018 and 2020. (Source: United Utilities).

Contact: Cumbria and Lancashire Hydrology team: [email protected] or Greater Manchester, Merseyside and Cheshire Hydrology team: [email protected]

Rainfall

Crown Copyright. All rights reserved. Environment Agency, 100024198, 2021 Figure 2. Total rainfall (as a percentage of the LTA) for hydrological areas across North West England for the current month, the last three months, the last six months, and the last 12 months, classed relative to an analysis of respective historic totals. HadUK data based on the Met Office 1km gridded rainfall dataset derived from rain gauges (Source: Met Office © Crown Copyright 2021). Provisional data based on Environment Agency 1km gridded rainfall dataset derived from Environment Agency intensity rain gauges.

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Above average rainfall Below average rainfall 1-Month Period for North-west England 1-Month Period for Cumbria and Lancashire 300% 300%

250% 250%

200% 200%

150% 150%

100% 100%

50% 50%

0% 0%

Nov-20 Nov-20 Sep-20 Oct-20 Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jun-21 Jul-21 Aug-21 Sep-20 Oct-20 Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jun-21 Jul-21 Aug-21

1-Month Period for Greater Manchester, Merseyside and 1-Month Period for Cumbria and Lancashire (Cumbria) Cheshire 300% 300%

250% 250%

200% 200%

150% 150%

100% 100%

50% 50%

Sep-20 Dec-20 Nov-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jun-21 Jul-21 Aug-21

Oct-20 0%

Nov-20 Aug-21 Sep-20 Oct-20 Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jun-21 Jul-21

1-Month Period for Cumbria and Lancashire (Lancashire) 1-Month Period for Esk (Cumb) 300% 300%

250% 250%

200% 200%

150% 150%

100% 100%

50% 50%

Sep-20 Jun-21 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jul-21 Aug-21

Oct-20 0%

Apr-21 May-21 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21 Jun-21 Jul-21 Aug-21

1-Month Period for Derwent (NW) 1-Month Period for Eden 300% 300%

250% 250%

200% 200%

150% 150%

100% 100%

50% 50%

Dec-20 Mar-21 Oct-20 Nov-20 Jan-21 Feb-21 Apr-21 May-21 Jun-21 Jul-21 Aug-21

0% Sep-20

Sep-20 Feb-21 Aug-21 Oct-20 Nov-20 Dec-20 Jan-21 Mar-21 Apr-21 May-21 Jun-21 Jul-21

Above average rainfall Below average rainfall 1-Month Period for Esk (Dumfries) 1-Month Period for Cheshire Rivers Group 300% 300%

250% 250%

200% 200%

150% 150%

100% 100%

50% 50%

May-21 Jul-21 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 Jun-21 Aug-21

0% Sep-20

Jun-21 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jul-21 Aug-21

1-Month Period for Kent 1-Month Period for Mersey and Irwell 300% 300%

250% 250%

200% 200%

150% 150%

100% 100%

50% 50%

Oct-20 Jun-21 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jul-21 Aug-21

Sep-20 0%

Jun-21 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21 Apr-21 May-21 Jul-21 Aug-21

1-Month Period for Douglas 1-Month Period for Ribble 300% 300%

250% 250%

200% 200%

150% 150%

100% 100%

50% 50%

0% 0%

Apr-21 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Mar-21 May-21 Jun-21 Jul-21 Aug-21

Jan-21 Sep-20 Oct-20 Nov-20 Dec-20 Feb-21 Mar-21 Apr-21 May-21 Jun-21 Jul-21 Aug-21

1-Month Period for Wyre and Lune 300%

250%

200%

150%

100%

50%

Mar-21 Sep-20 Oct-20 Nov-20 Dec-20 Jan-21 Feb-21 Apr-21 May-21 Jun-21 Jul-21 Aug-21

Figure 3: Monthly rainfall totals for the past 12 months expressed as a percentage of the long term average (1961-90), for North West England and its hydrological areas using HadUK data based on the Met Office 1km gridded rainfall dataset derived from rain gauges (Source: Met Office © Crown Copyright 2021). Provisional data based on Environment Agency 1km gridded rainfall dataset derived from Environment Agency intensity rain gauges.

Soil Moisture Deficit

Figure 4: Soil moisture deficits for weeks ending 3 August 20211 (left panel) and 31 August 20212 (right panel). Top row shows actual soil moisture deficits (mm) and bottom row shows the difference (mm) of the actual from the 1961-90 long term average soil moisture deficits. MORECS data for real land use (Source: Met Office © Crown Copyright, 2021). 6

River Flow

Figure 5: Monthly mean river flow for this month, expressed as a percentage of the month’s long term average and classed relative to analysis of historic monthly means (Source: Environment Agency).

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Ashbrook, WEAVER (NW) Ashton Weir, MERSEY Ranking derived from data for the period Dec-1977 to Dec-2017 Ranking derived from data for the period May-1976 to Dec-2017

28 50 45 24 40 20 35

16 30 25

12 20 Flow (cumecs)Flow Flow (cumecs)Flow 8 15 10 4 5 0 0 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21

Caton, LUNE Newby Bridge FMS, LEVEN (NW) Ranking derived from data for the period Jan-1959 to Dec-2017 Ranking derived from data for the period Jan-1972 to Dec-2017

105 40 35 90 30 75 25 60 20 45

Flow (cumecs)Flow (cumecs)Flow 30 10

15 5

0 0 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21

Seaton Mill, DERWENT (NW) Pooley Bridge, EAMONT Ranking derived from data for the period Sep-1960 to Dec-2017 Ranking derived from data for the period Jul-1970 to Dec-2017

80 25 70

60 20 50 15 40

30 10

Flow (cumecs)Flow (cumecs)Flow 20 5 10 0 0 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Samlesbury Pgs, RIBBLE (NW) Sheepmount, EDEN (NW) Ranking derived from data for the period May-1960 to Dec-2017 Ranking derived from data for the period Oct-1967 to Dec-2017

105 180 160 90 140 75 120 60 100

45 80

60 Flow (cumecs)Flow Flow (cumecs)Flow 30 40 15 20 0 0 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21

St Michaels FMS, WYRE Ranking derived from data for the period Oct-1963 to Dec-2017

8 Flow (cumecs)Flow

0 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21

Figure 6: Monthly mean river flows for the past 10 months for sites across North West England (Source: Environment Agency).

Groundwater Levels

Figure 7: Groundwater levels at the end of the month classed relative to an analysis of historic groundwater levels for the same month (Source: Environment Agency). Geological map reproduced with kind permission from the UK Groundwater Forum, British Geological Survey (BGS) © Natural Environment Research Council (NERC).

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data BROWN BANK LAY-BY BRUNTWOOD HALL OBH Ranking derived from data for the period Jul-1974 to Dec-2017 Ranking derived from data for the period Dec-1972 to Dec-2017

26.0 50.0

25.5 49.5

25.0 49.0

24.5 48.5

24.0 48.0

Level (mAOD) Level Level (mAOD) Level

23.5 47.5

23.0 47.0 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21

Crow Lady Farm T74 PRIORS HEYES Ranking derived from data for the period Apr-1973 to Dec-2017 Ranking derived from data for the period Sep-1972 to Dec-2017

11.0 34.0

33.5 10.5 33.0 10.0 32.5

9.5 32.0

31.5

9.0 Level (mAOD) Level Level (mAOD) Level 31.0 8.5 30.5

8.0 30.0 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21

SKIRWITH RICHMOND PARK (YEW TREE FARM REPLACEMENT) Ranking derived from data for the period Oct-1978 to Dec-2017 Ranking derived from data for Yew Tree Farm for the period Jun-1971 to Dec-2017 133.0 16.0

132.5 15.5

132.0 15.0

131.5 14.5

131.0 14.0

130.5 13.5 Level (mAOD) Level 130.0 (mAOD) Level 13.0

129.5 12.5

129.0 12.0 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21 Data up to February 2019 from original Yew Tree Farm site

Figure 8: End of month groundwater levels for the past 34 months for North West England groundwater sites (Source: Environment Agency).

Reservoir Stocks

Figure 9: The location of reservoirs that comprise the supply districts across North West England and selected individual reservoirs.

Reservoir Stocks

Total North West England Reservoir Stocks North Area Supply District: Ribble 100 100

90 90

80 80

70 70

60 60

50 50

40 40

30 30 Percentage of live capacity of Percentage live 20 Percentage capacity oflive 20

10 10

0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec North Area Supply District: Lakes Pennines Combined 100 100

90 90

80 80

70 70

60 60

50 50

40 40

30 30

20 20

Percentage of live capacity of Percentage live Percentage of live capacity of live Percentage

10 10

0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Peak Supply District: Longdendale Peak Supply District: Stockport 100 100

90 90

80 80

70 70

60 60

50 50

40 40

30 30

Percentage of live capacity of Percentage live 20 20 Percentage of live capacity of Percentage live

10 10

0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Rivington Group Haweswater Reservoir 100 Level 1 Level 2 Level 3 Enhanced monitoring and operations 90 100

80 90 80 70 70 60 60 50 50 40 40 30 30

Percentage of live capacity of Percentage live 20 20

10 Percentage ofcapacity live 10

0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Reservoir Stocks

Thirlmere Reservoir Haweswater + Thirlmere Stocks 100 100 90 90

80 80

70 70

60 60

50 50

40 40

30 30 Percentage of live capacity live of Percentage

20 20 Percentage of live capacity of Percentage live 10 10 0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ennerdale Water Crummock Water

Trigger 1 Trigger 2 Trigger 3 Trigger 4 Trigger 1 Trigger 2 Trigger 3 Trigger 4 -1.0 100

90 -0.5 80

70 0.0 60

0.5 50

Level (mBTWL) Level 1.0 30

1.5 capacity of Percentage live 10

2.0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Celyn and Brenig (Dee) Vyrnwy Reservoir 100 100

90 90

80 80

70 70

60 60

50 50

40 40

30 30 Percentage of live capacity of Percentage live

20 capacity of Percentage live 20

10 10

0 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 10: End of month reservoir stocks for supply districts across North West England and selected individual reservoirs for current and representative years; 1995, 2003, 2010, 2018 and 2020 (Source: United Utilities and Environment Agency).

Glossary

Term Definition

Aquifer A geological formation able to store and transmit water. Areal average rainfall The estimated average depth of rainfall over a defined area. Expressed in depth of water (mm). Artesian The condition where the groundwater level is above ground surface but is prevented from rising to this level by an overlying continuous low permeability layer, such as clay. Artesian Borehole Borehole where the level of groundwater is above the top of the borehole and groundwater flows out of the borehole when unsealed. Effective rainfall The rainfall available to percolate into the soil or produce river flow. Expressed in depth of water (mm). Flood Alert/Flood warning Three levels of warnings may be issued by the Environment Agency. Flood Alerts indicate flooding is possible. Flood Warnings indicate flooding is expected. Severe Flood Warnings indicate severe flooding. Groundwater The water found in an aquifer The arithmetic mean calculated from the historic record, usually Long Term Average (LTA) based on the period 1961-1990. However, the period used may vary by parameter being reported on (see figure captions for details). Met Office Rainfall and Evaporation Calculation System. This is a MORECS generic name for Met. Office services involving the routine calculation of soil moisture and evaporation for Great Britain and uses a grid of 40 x 40 km squares. River flow with the impacts of artificial influences removed. Artificial Naturalised Flow influences may include abstractions, discharges, transfers, augmentation and impoundments. HadUK HadUK area monthly rainfall totals are derived using the Met Office 1 km gridded dataset, which uses rain gauge observations. Recharge The process of increasing the water stored in the saturated zone of an aquifer. Expressed in depth of water (mm). Reservoir gross capacity The total capacity of a reservoir. Reservoir live capacity The reservoir capacity normally usable for storage to meet established reservoir operating requirements. Soil moisture deficit (SMD) The difference between the amount of water actually in the soil and the amount of water that the soil can hold. Expressed in depth of water (mm).

Categories for rainfall, river flows, groundwater levels Exceptionally high Value likely to fall within this band 5% of the time Notably high Value likely to fall within this band 8% of the time Above normal Value likely to fall within this band 15% of the time Normal Value likely to fall within this band 44% of the time Below normal Value likely to fall within this band 15% of the time Notably low Value likely to fall within this band 8% of the time Exceptionally low Value likely to fall within this band 5% of the time

Units mAOD Metres Above Ordnance Datum (mean sea level at Newlyn Cornwall). mBTWL meters Below Top Water Level

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