Monthly water situation report - North East Area

Monthly water situation report - North East Area

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. www.gov.uk/environment-agency © Environment Agency 2019 1 Monthly water situation report Summary – March 2019 March was a particularly wet month with above average monthly rainfall totals across the North East Area. Monthly mean river flows are now classed as ‘normal’ or higher for the time of year at all indicator sites.

Groundwater levels in the North East area’s aquifers were variable in March, ranging from ‘below normal’ to ‘exceptionally high’. Soil moisture deficits increased slightly but all catchments are classed as ‘wet’. Reservoir stocks have generally increased this month and the majority are above average for the time of the year.

Rainfall March was a wet month with rainfall exceeding the monthly long term average (LTAs) in all catchments. The monthly rainfall totals for March range from 110% of LTA in the Seaham, Peterlee Coastal catchment to 170% of LTA in the Tyne catchment. The majority of March’s rainfall fell during the first half of the month, with two Met Office named storms Freya and Gareth bringing widespread heavy rainfall across the area. The Seaham, Peterlee Coastal area recorded above average rainfall for the first time since April 2018.

The cumulative rainfall total for the last 12 months is ‘notably low’ in all catchments with the exception of the Tweed and Northumbria North Sea tributary catchments which are classed as ‘exceptionally low’.

It is interesting to note that the 12 month rainfall accumulations to March for the Tweed and Northumbria North Sea tributary catchments are the 3rd and 4th driest since 1910 respectively. Soil Moisture Deficit Soil moisture deficits (SMDs) decreased during the first part of March in response to the wet weather and gradually dried towards the end of March, however soils throughout the North East remain ‘wet'. River Flows Monthly mean flows for March increased at all the indicator sites across the area compared to the previous month. Monthly flows range from 74% of LTA at Hartford Bridge on the River Blyth to 191% of LTA at Stanhope on the River Wear.

Daily mean flows show that all rivers experienced ‘exceptionally high’ flows during March particularly on the 16th as a response to Storm Gareth. Groundwater Levels The unconfined part of the Magnesian Limestone aquifer, represented by the typically responsive Aycliffe borehole, showed a ‘below normal’ groundwater level for March, despite ‘notably high’ rainfall in the catchment for the month. The dip reading was taken on March 20th, substantial rainfall in the catchment on March 15th likely to have passed through this part of the aquifer by the time the reading was taken. The levels in the semi-confined and confined parts of the Magnesian Limestone, represented by West Hall Farm and Red Lion respectively, are classed as ‘normal’ and ‘exceptionally high’ for the time of year.

With slower response times in comparison to the unconfined part, these sites show a general downward trend in groundwater level. With below normal rainfall amounts observed in the Wear and Tees catchments over the last six months, it appears that heavier rainfall events in early 2018 continue to recharge these parts of the Magnesian Limestone.

Groundwater levels in the Fell Sandstone aquifer have seen a slight increase in the semi-confined part, represented by Royalty Observation, following a downward trend since the sharp increase in April 2018. The groundwater level status here was ‘normal’ for March. The level in the unconfined part of the North East Area

Monthly water situation report - North East Area

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.

www.gov.uk/environment-agency © Environment Agency 2019 2 Fell Sandstone, represented by the responsive Townlaw borehole, was shown to be ‘below normal’ for March but this is most likely due to the negligible amounts of rainfall in the catchment in the three days preceding the borehole dip.

Reservoir Storage Reservoir stocks have increased during March with the exception of the Tees reservoirs at Cow Green and the Lune/Balder group. Stocks in all reservoirs except Derwent and the North Tynedale group are at above average levels for the time of the year. The compensation flow from Derwent reservoir continued to be substituted by releases from the Kielder tunnel in order to conserve water for public water supply. Water was also transferred into Mosswood water treatment works from the Kielder tunnel and pumped from Barrasford on the North Tyne to help refill West Hallington reservoir in the North Tynedale group.

Current % Stocks Previous Month % Stock Kielder 94.4 90.0 North Tynedale Group 83.8 78.4 Derwent 61.0 51.3 Durham Group 94.8 92.3 Lune Balder Group 95.3 96.6 Cow Green 99.5 99.7 Author: GWHCL team

Monthly water situation report - North East Area

www.gov.uk/environment-agency © Environment Agency 2019 3 Rainfall Total rainfall (as a percentage of the long term average) for hydrological areas across North East 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. NCIC (National Climate Information Centre) data based on the Met Office 5km gridded rainfall dataset derived from rain gauges (Source: Met Office © Crown Copyright 2019).

Provisional data based on Environment Agency 1km gridded rainfall dataset derived from Environment Agency intensity rain gauges.

www.gov.uk/environment-agency © Environment Agency 2019 4 Above average rainfall Below average rainfall 0% 50% 100% 150% 200% Apr-18 Jul-18 Oct-18 Jan-19 1-Month Period for Tweed 0% 50% 100% 150% 200% Apr-18 Jul-18 Oct-18 Jan-19 1-Month Period for Northumbria North Sea Tribs 0% 50% 100% 150% 200% Apr-18 Jul-18 Oct-18 Jan-19 1-Month Period for Tyne 0% 50% 100% 150% 200% Apr-18 Jul-18 Oct-18 Jan-19 1-Month Period for Wear 0% 50% 100% 150% 200% Apr-18 Jul-18 Oct-18 Jan-19 1-Month Period for Seaham, Peterlee Coastal Area 0% 50% 100% 150% 200% Apr-18 Jul-18 Oct-18 Jan-19 1-Month Period for Tees

www.gov.uk/environment-agency © Environment Agency 2019 5 Soil Moisture Deficit

www.gov.uk/environment-agency © Environment Agency 2019 6 River Flow Some features of this map are based on digital spatial data licensed from the Centre for Ecology and Hydrology, © CEH. Includes material based on Ordnance Survey 1:50 000 maps with the permission of the controller of Her Majesty’s Stationery Office © Crown copyright. All rights reserved. Environment Agency, 100026380, 2019.

www.gov.uk/environment-agency © Environment Agency 2019 7 Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data

www.gov.uk/environment-agency © Environment Agency 2019 8 Groundwater Levels Some features of this map are based on digital spatial data licensed from the Centre for Ecology and Hydrology, © CEH. Includes material based on Ordnance Survey 1:50 000 maps with the permission of the controller of Her Majesty’s Stationery Office © Crown copyright. All rights reserved. Environment Agency, 100026380, 2019.

www.gov.uk/environment-agency © Environment Agency 2019 9 Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data .

42.0 42.5 43.0 43.5 44.0 44.5 45.0 45.5 46.0 Jun-16 Oct-16 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Level (mAOD) ROYALTY OBSERV. Ranking derived from data for the period Dec-1990 to Dec-2012 137.0 137.5 138.0 138.5 139.0 139.5 140.0 Jun-16 Oct-16 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Level (mAOD) TOWNLAW Ranking derived from data for the period Aug-2001 to Nov-2012 75 77 79 81 83 85 Jun-16 Oct-16 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Level (mAOD) AYCLIFFE NRA2 Ranking derived from data for the period Mar-1979 to Dec-2012 3.0 3.5 4.0 4.5 5.0 5.5 6.0 Jun-16 Oct-16 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Level (mAOD) RED LION Ranking derived from data for the period Aug-1993 to Dec-2012 1.0 1.4 1.8 2.2 2.6 3.0 Jun-16 Oct-16 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Level (mAOD) WEST HALL FARM Ranking derived from data for the period Mar-1979 to Dec-2012

www.gov.uk/environment-agency © Environment Agency 2019 10 Reservoir Stocks 10 20 30 40 50 60 70 80 90 100 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Percentage of live capacity Kielder 2019 Min Max Mean 10 20 30 40 50 60 70 80 90 100 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Percentage of live capacity N Tyne Group 2019 Min Max Mean 10 20 30 40 50 60 70 80 90 100 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Percentage of live capacity Derwent 2019 Min Max Mean 10 20 30 40 50 60 70 80 90 100 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Percentage of live capacity Durham 2019 Min Max Mean 10 20 30 40 50 60 70 80 90 100 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Percentage of live capacity Cow Green 2019 Min Max Mean 10 20 30 40 50 60 70 80 90 100 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Percentage of live capacity Lune Balder 2019 Min Max Mean

www.gov.uk/environment-agency © Environment Agency 2015 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). Effective rainfall The rainfall available to percolate into the soil or produce river flow. Expressed in depth of water (mm). Groundwater The water found in an aquifer Recharge The process of increasing the water stored in the saturated zone of an aquifer. Expressed in depth of water (mm). Reservoir live capacity The reservoir capacity normally usable for storage to meet established reservoir operating requirements.

It is the total capacity less that not available because of operating agreements or physical restrictions. Only under abnormal conditions, such as a severe water shortage might this additional water be extracted.

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 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 cumecs Cubic metres per second (m3 s-1 ) mAOD Metres Above Ordnance Datum (mean sea level at Newlyn Cornwall).

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