Monthly Water Situation Report Yorkshire Area

Monthly water situation report Yorkshire Area

Summary – November 2019 A very wet month as a result of numerous frontal storm conditions ensured above average monthly rainfall totals throughout Yorkshire. Many rivers were in the exceptionally or notably high range with flooding in South Yorkshire and in the Hull catchment. Soils were fully saturated throughout the month and groundwater levels were high, seeing the highest recorded dip level for November in the Millstone Grit and the Chalk. Reservoirs were close to full capacity throughout the month.

Rainfall Yorkshire experienced very unsettled and very wet weather during November. All catchments recorded above their monthly long term average (LTA) total with the Don and Hull catchments recording over twice their monthly LTA.

Frequent episodes of frontal rain storms dominated ensuring there were many wet days. However, some of the storms produced significant rainfall totals, most notably on:

 the 7th to 8th November: a storm front aligning in a north-east to south-west direction through the Hull and Don catchments ensured significant rainfall totals occurred over peak 12-hour to 48-hour accumulations. Especially through the middle Don, lower Rother, middle to lower Dearne, and the lower Hull catchments. The lower Rother and middle to lower Dearne catchments recorded over a months’ worth of rainfall in 18 hours while the lower Hull catchment recorded just over half a months’ worth of rainfall in 12 hours.

 the 14th to 15th November: a storm front twisting in a northerly direction from the south of the area ensured locations within the Hull catchment received over half a months’ worth of rainfall over 4 to 6 hours. Sheffield, Rotherham, and Doncaster also recorded daily totals on the 14th November equivalent to 30% to 40% of the LTA.

 the 27th November: Localised heavy showers within central North Yorkshire and eastern catchments produced up to 30% to 50% of the monthly LTA over a 24-hour period.

With regards to the individual catchment average rainfall totals, using the Met Office National Climate Information Centre (NCIC) dataset from 1891, it is showing to be the wettest November for the Don catchment, the 2nd wettest November for the Hull catchment and 5th wettest November for the Esk catchment. Looking at the longer periods, it’s also the wettest 3-month period ending November for the Don and Hull catchments, the wettest 5- month period ending November for the Don and Calder catchments, and the 2nd wettest 5-month period ending November for the Hull catchment.

Soil Moisture Deficit (SMD) The soils were almost fully saturated at the start of November and remained saturated and wet throughout the month, leaving no additional storage capacity available.

River Flows River flows during November were in the exceptionally high range within the Rother, Don, Went, Hull, Derwent and Rye catchments, reflecting the locations where the most significant rainfall totals occurred. Locations in the Rother, lower Don and Went catchments also recorded the highest November monthly mean flow on record. Apart from the Aire and Ure catchments, which were within the normal range, all the other rivers were notably high or above normal. Monthly mean flows ranged from 96% of the LTA on the upper Ure catchment to more than 400% of the LTA on the Rother, Don, Went and upper Hull catchments.

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. © Environment Agency 2019

River flows in the Pennine fed catchments were already high at the beginning of November and the rain during the first few days ensured they remained high. The storm over the 7th and the 8th November had a significant impact in South Yorkshire which experienced extensive flooding. The highest peaks on record were measured at Rotherham (River Don), Doncaster (River Don), Adwick Le Street Whitecross Bridge (Ea Beck) and Kirk Bramwith (River Don). Many other locations over South Yorkshire recorded the second highest peak, just behind the late June 2007 flood event.

The Yorkshire rivers responded quickly to all the rainfall events that followed, ensuring frequent high peak flows throughout the month. There was a brief respite when flows slowly declined between the 17th to the 22nd November, but they began to increase once again as wetter weather returned towards the end of the month.

In the groundwater dominated catchments in the east, the Rye and Derwent catchments had flows that were in the notably or exceptionally high range for the majority of the month, fluctuating with a series of multiple peaks. In the River Hull, flows were constantly in the exceptionally high range as they increased through the month in response to rising groundwater levels in the Chalk. Flows in Mires Beck and the River Foulness, also in the exceptionally high flow range, showed a more fluctuating pattern in response to rainfall events.

Significant peak levels were recorded across the Hull catchment during November. Over the 7th and the 8th Burstwick Hall Road Bridge, located on Burstwick Drain, recorded its 3rd highest peak in a 20 year record. Over the 14th to the 16th Brough, located on Ellerker Drain, recorded its highest peak in a 25 year record while North Cave, located on Mires Beck, recorded its 4th highest peak in a 35 year record. Then on the 28th Wansford Snakeholm Lock, located on West Beck, recorded its 3rd highest peak in a 31 year record, Beverley Shipyard, located on the River Hull, recorded its 2nd highest peak in a 25 year record and Dunswell Ennerdale Bridge, located on the River Hull, recorded its highest peak in a 17 year record.

Groundwater Levels Magnesian Limestone The groundwater level at Brick House Farm continued to rise and was above the average for the time of year.

Millstone Grit The groundwater level at Hill Top Farm continued to rise and was at the highest recorded dip level for November.

Sherwood Sandstone The groundwater level in the Sherwood Sandstone, measured at both Great Ouseburn and Riccal Approach, had increased during the month and were well above average for the time of year. The groundwater levels measured at Great Ouseburn were almost at the maximum previously recorded for November.

Corallian Limestone The groundwater level at Sproxton had decreased during the month but still remained above the average for the time of year. The levels measured at East Ness continued to rise and were above average for the time of year.

Chalk The groundwater level in the northern area of the aquifer, as monitored at Wetwang, sharply increased and was at the highest recorded dip level for November. At Dalton Estate in the south of the aquifer the groundwater level had increased to well above average level for the time of year.

Reservoir Storage Overall reservoir stocks were very high at the start of November and despite a slight reduction by the end of the month, remained well above the LTA and at near full capacity.

Environmental Impact No abstraction licences had any Hands off Flow (HOF) in force within Yorkshire however, 21 were on advance warning notifications although they were still able to abstract.

Author: Yorkshire Hydrology

Rainfall

Above average rainfall Below average rainfall 1-Month Period for Swale (NE) 1-Month Period for Ure

200% 200%

150% 150%

100% 100%

50% 50%

0% 0% Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19

1-Month Period for Nidd 1-Month Period for Ouse

200% 250%

200% 150%

150%

100%

50% 50%

0% 0% Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19

1-Month Period for Wharfe 1-Month Period for Dales North Sea Tribs

200% 250%

200% 150%

150%

100%

50% 50%

0% 0% Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19

1-Month Period for Rye 1-Month Period for Derwent (NE)

250% 250%

200% 200%

150% 150%

100% 100%

50% 50%

0% 0% Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19

Above average rainfall Below average rainfall 1-Month Period for Aire 1-Month Period for Calder

200% 250%

200% 150%

150%

100%

50% 50%

0% 0% Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19

1-Month Period for Don 1-Month Period for Hull and Humber

250% 250%

200% 200%

150% 150%

100% 100%

50% 50%

0% 0% Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19 Dec-18 Jan-19 Feb-19 Mar-19 Apr-19 May-19 Jun-19 Jul-19 Aug-19 Sep-19 Oct-19 Nov-19

Soil Moisture Deficit

River Flow

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Addingham, WHARFE Birstwith, NIDD Ranking derived from data for the period Dec-1973 to Dec-2017 Ranking derived from data for the period Dec-1976 to Dec-2017

20 45 18 40 16 35 14 30 12 25 10 20 8 15

Flow (cumecs) Flow (cumecs) Flow 6 10 4 5 2 0 0 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Briggswath, ESK Buttercrambe, DERWENT Ranking derived from data for the period Jan-1993 to Dec-2017 Ranking derived from data for the period Sep-1973 to Dec-2017

20 50

40 15

30 10 20 Flow (cumecs) Flow (cumecs) Flow 5 10

0 0 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19

Crakehill Topcliffe, SWALE Doncaster, DON Ranking derived from data for the period Jun-1980 to Dec-2017 Ranking derived from data for the period Jul-1959 to Dec-2017

90 70 80

60 70

50 60 50 40 40 30 30 Flow (cumecs)Flow 20 (cumecs)Flow 20 10 10 0 0 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19

Elland, CALDER Hunsingore, NIDD Ranking derived from data for the period Jul-1971 to Dec-2017 Ranking derived from data for the period Oct-1968 to Dec-2017

25 25

20 20

15 15

10 10 Flow (cumecs) Flow (cumecs) Flow

5 5

0 0 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19

Kildwick, AIRE Kilgram Bridge, URE Ranking derived from data for the period Aug-1971 to Dec-2017 Ranking derived from data for the period Aug-1971 to Dec-2017

25 50 20 40 15 30

10 20 Flow (cumecs)Flow (cumecs)Flow

5 10

0 0 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Ness, RYE Skelton, OUSE Ranking derived from data for the period Sep-1974 to Dec-2017 Ranking derived from data for the period Sep-1969 to Dec-2017

12 160 10 140

8 120 100 6 80

4 60 Flow (cumecs) Flow (cumecs) Flow 40 2 20 0 0 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19

Tadcaster, WHARFE Walden Stubbs, WENT Ranking derived from data for the period Jul-1991 to Dec-2017 Ranking derived from data for the period Oct-1979 to Dec-2017

4.0 60 3.5 50 3.0

40 2.5

2.0 30 1.5 20 Flow (cumecs)Flow (cumecs)Flow 1.0 10 0.5

0 0.0 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19

Wansford Snakeholm Lock - West Beck, WEST BECK Whittington, ROTHER Ranking derived from data for the period Nov-1988 to Dec-2017 Ranking derived from data for the period Nov-1979 to Dec-2017

8 10 7

6 8 5 6 4

3 4

Flow (cumecs) Flow 2 (cumecs) Flow 2 1

0 0 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19 Feb-19 Apr-19 Jun-19 Aug-19 Oct-19 Dec-19

Groundwater Levels

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Brick House Fm Dalton Estate Well Ranking derived from data for the period Oct-1979 to Nov-2017 Ranking derived from data for the period Jan-1889 to Nov-2017

18 23

17 21 16 19 15

14 17

13 15 Level (mAOD) Level 12 (mAOD) Level 13 11

10 11 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Jun-19 Oct-19 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Jun-19 Oct-19

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Great Ouseburn Hill Top Fm Ranking derived from data for the period Jan-1976 to Nov-2017 Ranking derived from data for the period Oct-1973 to Nov-2017

17 128

128 17 127 16 127

16 126

126 15 Level (mAOD) Level (mAOD) Level 125 15 125

14 124 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Jun-19 Oct-19 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Jun-19 Oct-19

Riccall Approach Farm Sproxton Ranking derived from data for the period Feb-1977 to Nov-2017 Ranking derived from data for the period May-1975 to Nov-2017

7 50

7 49 6 48 6 5 47 5 46

4 45

Level (mAOD) Level 4 (mAOD) Level 44 3 3 43 2 42 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Jun-19 Oct-19 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Jun-19 Oct-19

Wetwang Ranking derived from data for the period Oct-1971 to Nov-2017

33 31 29 27 25 23 Level (mAOD) Level 21 19 17 Feb-17 Jun-17 Oct-17 Feb-18 Jun-18 Oct-18 Feb-19 Jun-19 Oct-19

Reservoir Stocks – Data from Water Company

Yorkshire Supply (data supplied by Water Company) 100

30 Percentage of live capacity

Weekly LTA (historic) 10 Maximum (historic) Minimum (historic) 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec This graph is produced from Yorkshire Water © Crown Copyright data.

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.

Cumecs Cubic metres per second (m3s-1)

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.

Long term average (LTA) The arithmetic mean calculated from the historic record, usually based on the period 1961-1990. However, the period used may vary by parameter being reported on (see figure captions for details). mAOD Metres Above Ordnance Datum (mean sea level at Newlyn Cornwall).

MORECS Met Office Rainfall and Evaporation Calculation System. Met Office service providing real time calculation of evapotranspiration, soil moisture deficit and effective rainfall on a 40 x 40 km grid.

Naturalised flow River flow with the impacts of artificial influences removed. Artificial influences may include abstractions, discharges, transfers, augmentation and impoundments.

NCIC National Climate Information Centre. NCIC area monthly rainfall totals are derived using the Met Office 5 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 capacity of the reservoir that is normally usable for storage to meet established reservoir operating requirements. This excludes any capacity not available for use (e.g. storage held back for emergency services, operating agreements or physical restrictions). May also be referred to as ‘net’ or ‘deployable’ capacity.

Soil moisture deficit (SMD) The difference between the amount of water actually in the soil and the amount of water the soil can hold. Expressed in depth of water (mm).