Monthly Water Situation Report East of England

Monthly water situation report East of England

Summary – March 2017 March continues the dry period experienced in East Anglia since July 2016; only November has seen above average rainfall. The driest parts of the area are the East Suffolk and Essex catchments, followed by the Cam and Lark catchments. Soil moisture deficit has increased to above normal conditions as a result of the rainfall deficit. River flows are below normal in the Ely Ouse and North- west Norfolk catchments, with the river Cam showing notably low conditions. Groundwater recharge continues at the majority of sites, but at a slower rate than in previous years, causing the majority of sites to be classified as below normal. Rainfall East Anglia received an average of 33 mm of rainfall, 71% of the long term average during March. This continues a predominantly dry period which started 9 months ago in July 2016, with only November seeing above average rainfall. South Essex is particularly dry, with only 19 mm of rainfall, 47% of long term average in March. This has made the total rainfall in the last 9 months the 2nd driest since record began, with just 61% of average rainfall. Soil Moisture Deficit/Recharge Soil Moisture Deficit (SMD) has increased to above normal conditions, reaching an average value of 22 mm in the area. This is in response to the reduced rainfall, increase in temperature and beginning of the growing season. River Flows River flows have fallen at 13 sites due to the below average rainfall; only the rivers in the north Norfolk have shown a flow increase during March. The rivers in the Ely Ouse and NW Norfolk catchments are below normal due to the reduced recharge experienced in the chalk, following lower than average effective rainfall over the winter period. The exception to this is the River Wissey, where flows were maintained by the previous recharge experienced in June 2016. Groundwater Levels Groundwater recharge continues at the majority of sites. Only 4 sites have stopped recharging: the Upper Ouse Limestone, the Ivel Greensand, and the Lark and Ivel Chalks. Despite the recharge, 11 of the 18 sites are classified as below normal due to the below average effective rainfall over the recharge period. Reservoir Storage The levels of the 5 reported reservoirs in the area were sustained or increased during March and all are close or above their operating curves. Forward Look Probabilistic ensemble projections for river flows at key sites June 2017: There is an increased probability of flows being below the normal range at most groundwater fed rivers this June, but there is a reduced probability of exceptionally low flows with exception of the Ely Ouse at Denver, the River Ouse at Offord and the River Stiffkey. September 2017: There is an increased probability of flows being below the normal range at most groundwater fed rivers this September, but there is a reduced probability of notably low flows with exception of the Ely Ouse at Denver and the River Stiffkey.

Probabilistic ensemble projections for groundwater levels in key aquifers September 2017: Therfield Rectory is showing an increased likelihood of exceptionally low levels, whilst Redlands shows an increased likelihood of notably low levels. The rest of the area shows an increased likelihood of normal or below normal levels in September. March 2018: The forecast models are currently showing a spread of results across each site, however there is a slightly increased likelihood of levels being below the normal range expected next March. Author: Hydrology & Operations Contact details: 03708506506

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 2017

Rainfall March 2017

Above average rainfall Below average rainfall

250% 1-Month Period for East Anglia 250% 1-Month Period for Upper Bedford Ouse

200% 200%

150% 150%

100% 100%

50% 50%

0% 0%

May May

Jun Jun

Jan Jan

Feb Feb

Mar Mar

Apr Apr

Oct Oct

Jul Jul

Aug Aug

Sep Sep

Nov Nov

Dec Dec

- -

16 16

- -

16 16

- -

16 16

17 17

16 16

16 16 16 16 250% 1-Month Period for Lower Bedford Ouse 250% 1-Month Period for Central Area Fenland

200% 200%

150% 150%

100% 100%

50% 50%

0% 0%

May May

Jun Jan Jun Jan

Feb Mar Feb Mar

Apr Oct Apr Oct

Jul Jul

Aug Sep Nov Dec Aug Sep Nov Dec

- -

- - - -

16 16

- - - -

------

16 16

- -

16 17 16 17

17 17 17 17

16 16 16 16 16 16 16 16 16 16 250% 1-Month Period for Cam 250% 1-Month Period for NW Norfolk and Wissey

200% 200%

150% 150%

100% 100%

50% 50%

0% 0%

May May

Jun Jan Jun Jan

Feb Mar Feb Mar

Apr Oct Apr Oct

Jul Jul

Aug Sep Nov Dec Aug Sep Nov Dec

- -

- - - -

16 16

- - - -

------

16 16

- -

16 17 16 17

17 17 17 17

16 16 16 16 16 16 16 16 16 16 250% 1-Month Period for Little Ouse and Lark 250% 1-Month Period for North Norfolk

200% 200%

150% 150%

100% 100%

50% 50%

0% 0%

May May

Jun Jan Jun Jan

Feb Mar Feb Mar

Apr Oct Apr Oct

Jul Jul

Aug Sep Nov Dec Aug Sep Nov Dec

- -

- - - -

16 16

- - - -

------

16 16

- -

16 17 16 17

17 17 17 17

16 16 16 16 16 16 16 16 16 16

Above average rainfall Below average rainfall

250% 1-Month Period for Broadland Rivers 250% 1-Month Period for East Suffolk

200% 200%

150% 150%

100% 100%

50% 50%

0% 0%

May May

Jun Jun

Jan Jan

Feb Feb

Mar Mar

Apr Apr

Oct Oct

Jul Jul

Aug Aug

Sep Sep

Nov Nov

Dec Dec

- -

16 16

- -

16 16

- -

16 16

17 17

16 16

16 16 16 16 250% 1-Month Period for North Essex 250% 1-Month Period for South Essex

200% 200%

150% 150%

100% 100%

50% 50%

0% 0%

May May

Jun Jan Jun Jan

Feb Mar Feb Mar

Apr Oct Apr Oct

Jul Jul

Aug Sep Nov Dec Aug Sep Nov Dec

- -

- - - -

16 16

- - - -

------

16 16

- -

16 17 16 17

17 17 17 17

16 16 16 16 16 16 16 16 16 16

Soil Moisture Deficit Data based on MORECS dataset (Met Office © Crown Copyright) ─── 2015-16 ─ ─ ─ 2014-15 Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data

East Anglia Ranking derived from data for the period Jan-1961 to Dec-2012 0

80 SMD (mm) SMD 100

120

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

River Flow March 2017

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Cappenham, TOVE Willen, OUZEL Ranking derived from data for the period Feb-1962 to Dec-2012 Ranking derived from data for the period Jan-1962 to Dec-2012

6.0 16 5.0 14 12 4.0 10 3.0 8

2.0 6

Flow (cumecs)Flow (cumecs)Flow 4 1.0 2 0.0 0 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Roxton, OUSE (AN) Blunham, IVEL Ranking derived from data for the period Oct-1972 to Dec-2012 Ranking derived from data for the period Aug-1959 to Dec-2012

12 50 10

40 8

30 6

20 4

Flow (cumecs)Flow (cumecs)Flow

10 2

0 0 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17

Offord(Gross Flows), OUSE (AN) Dernford, CAM (AN) Ranking derived from data for the period Jan-1970 to Dec-2012 Ranking derived from data for the period Feb-1949 to Dec-2012

120 5.0 4.5 100 4.0 3.5 80 3.0 60 2.5 2.0

40 Flow (cumecs)Flow Flow (cumecs)Flow 1.5 1.0 20 0.5 0 0.0 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17

Temple, LARK Abbey Heath, LITTLE OUSE Ranking derived from data for the period Nov-1960 to Dec-2012 Ranking derived from data for the period Jun-1968 to Dec-2012

5.0 16 4.5 4.0 14 3.5 12 3.0 10 2.5 8 2.0

6 Flow (cumecs)Flow Flow (cumecs)Flow 1.5 4 1.0 0.5 2 0.0 0 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17

Northwold Total, WISSEY Denver Ely Ouse, OUSE (AN) Ranking derived from data for the period Jul-1983 to Dec-2012 Ranking derived from data for the period Nov-1971 to Dec-2012

7 50

6 40 5

4 30

3 20 Flow (cumecs)Flow 2 (cumecs)Flow 10 1

0 0 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data Marham, NAR Heacham, HEACHEM Ranking derived from data for the period Apr-1982 to Dec-2012 Ranking derived from data for the period Nov-1965 to Dec-2012

3.0 1.0 0.9 2.5 0.8 0.7 2.0 0.6 1.5 0.5 0.4

1.0 Flow (cumecs)Flow Flow (cumecs)Flow 0.3 0.2 0.5 0.1 0.0 0.0 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17

Ingworth, BURE Swanton Morley Total Flow, WENSUM Ranking derived from data for the period Jun-1959 to Dec-2012 Ranking derived from data for the period Oct-1969 to Dec-2012

3.0 10 9 2.5 8 7 2.0 6 1.5 5 4

1.0 Flow (cumecs)Flow Flow (cumecs)Flow 3 2 0.5 1 0.0 0 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17

Needham Weir Total, WAVENEY LOWER Lexden, COLNE (AN) Ranking derived from data for the period Dec-1963 to Dec-2012 Ranking derived from data for the period Oct-1959 to Dec-2012

7 12 6 10 5 8 4 6 3

4 Flow (cumecs)Flow Flow (cumecs)Flow 2

2 1

0 0 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17

Springfield, CHELMER Ranking derived from data for the period Nov-1965 to Dec-2012

2 Flow (cumecs)Flow

0 Jun-16 Aug-16 Oct-16 Dec-16 Feb-17 Apr-17

Groundwater Levels March 2017

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data FRINGFORD - GREAT OOLITE BIGGLESWADE Ranking derived from data for the period Sep-1980 to Dec-2012 Ranking derived from data for the period Mar-1968 to Dec-2012

99 28.0

98 27.5

97 27.0

96 26.5

95 26.0

Level (mAOD) Level (mAOD) Level

94 25.5

93 25.0 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data THERFIELD RECTORY REDLANDS HALL Ranking derived from data for the period Jan-1883 to Dec-2012 Ranking derived from data for the period Aug-1963 to Dec-2012

52 91

47 86

Level (mAOD) Level (mAOD) Level 76 37

71 32 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17

LINTON GOG MAGOG Ranking derived from data for the period Jan-1980 to Dec-2012 Ranking derived from data for the period Jan-1980 to Dec-2012

31 18

30 17 29 16 28 15 27

14 Level (mAOD) Level Level (mAOD) Level 26

25 13

24 12 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17

BURY ST EDMUNDS NEWMARKET Ranking derived from data for the period May-1983 to Dec-2012 Ranking derived from data for the period Feb-1983 to Dec-2012

33 17

32 16 31

30 15 29

28 14 Level (mAOD) Level Level (mAOD) Level 27 13 26

25 12 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17

KENNINGHALL BRECKLAND Ranking derived from data for the period Aug-1973 to Dec-2012 Ranking derived from data for the period Jan-1971 to Dec-2012

33 29 32 28 31 30 27

29 26 28

27 25 Level (mAOD) Level Level (mAOD) Level 26 24 25 23 24 23 22 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data WASHPIT FARM ROUGHAM BIRCHAM TOFTS Ranking derived from data for the period May-1950 to Dec-2012 Ranking derived from data for the period Sep-1971 to Dec-2012

50 49 50 48 48 47 46 46 45 44 44

42 Level (mAOD) Level Level (mAOD) Level 43 42 40 41 40 38 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17

EAST KINGS LYNN CASTLE FARM Ranking derived from data for the period Jan-1987 to Dec-2012 Ranking derived from data for the period Mar-1967 to Dec-2012

12.0 24

11.5 22

11.0 20

10.5 18

10.0 16

Level (mAOD) Level (mAOD) Level

9.5 14

9.0 12 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17

OLD PRIMARY SCHOOL, South Creake PUG COTTAGE Ranking derived from data for the period Sep-1952 to Dec-2012 Ranking derived from data for the period Feb-1991 to Dec-2012

24 2.0 1.8 23 1.6 22 1.4

21 1.2 1.0 20

0.8 Level (mAOD) Level 19 (mAOD) Level 0.6 0.4 18 0.2 17 0.0 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17

THE SPINNEY SMEETHAM HALL COTT. Ranking derived from data for the period Nov-1952 to Dec-2012 Ranking derived from data for the period Jan-1964 to Dec-2012

12.0 30.0

11.5 29.5 29.0 11.0 28.5 10.5 28.0 10.0 27.5

9.5 27.0 Level (mAOD) Level Level (mAOD) Level 26.5 9.0 26.0 8.5 25.5 8.0 25.0 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17 Jun-14 Oct-14 Feb-15 Jun-15 Oct-15 Feb-16 Jun-16 Oct-16 Feb-17

Reservoir Stocks March 2017

─── 2015-2016 ─── Normal Operating Curve ─── Drought Alert Curve ── ─ 1995-1996

Grafham Alton

100 100 90 90 80 80 70 70 60 60 50 50 40 40 30 30

20 20

Percentage of live capacity live Percentageof capacity live Percentageof 10 10 0 0 Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov

─── 2015-2016 ─── Normal Operating Curve ─── Drought Alert Curve ── ─ 1995-1996 Ardleigh Abberton

100 100 90

80 80 70

60 60 50 40 40 30

20 20 n.b. from 20/01/2014 Abberton %full is based

Control curve 1 on increased “19m.Volume”

Percentage of live capacity live Percentageof capacity live Percentageof Control curve 2 n.b. from 29/09/2014 Abberton %full is based 10 on increased “20m.Volume” 0 0 Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov

Hanningfield

100 90 80 70 60 50 40 30 20

Control curve Percentage of live capacity live Percentageof 10 0 Jan Mar May Jul Sep Nov Jan Mar May Jul Sep Nov

Forward Look – River Flows

Exceptionally high or low levels are those which would typically occur 5% of the time within the historic record. Notably high or low levels are those which would typically occur 8% of the time. Above normal or below normal levels are those which would typically occur 15% of the time. Normal levels are those which would typically occur 44% of the time within the historic record.

Probabilistic ensemble projections of river flows at key indicator sites in June 2017. Pie charts indicate probability, based on climatology, of the surface water flow at each site being e.g. exceptionally low for the time of year. (Source: Centre for Ecology and Hydrology, Environment Agency) Geological map reproduced with kind permission from UK Groundwater Forum, BGS © NERC. Crown copyright. All rights reserved. Environment Agency, 100026380, 2017. ^ “Naturalised” flows are projected for these sites’

Probabilistic ensemble projections of river flows at key indicator sites in September 2017. Pie charts indicate probability, based on climatology, of the surface water flow at each site being e.g. exceptionally low for the time of year. (Source: Centre for Ecology and Hydrology, Environment Agency) Geological map reproduced with kind permission from UK Groundwater Forum, BGS © NERC. Crown copyright. All rights reserved. Environment Agency, 100026380, 2017. ^ “Naturalised” flows are projected for these sites’

Forward Look - Groundwater

Probabilistic ensemble projections of groundwater levels at key indicator sites for end of September 2017. Pie charts indicate probability, based on climatology, of the groundwater level at each site being e.g. exceptionally low for the time of year. (Source: Environment Agency) Geological map reproduced with kind permission from UK Groundwater Forum, BGS © NERC. Crown copyright. All rights reserved. Environment Agency, 100026380, 2017.

Probabilistic ensemble projections of groundwater levels at key indicator sites for end of March 2018. Pie charts indicate probability, based on climatology, of the groundwater level at each site being e.g. exceptionally low for the time of year. (Source: Environment Agency) Geological map reproduced with kind permission from UK Groundwater Forum, BGS © NERC. Crown copyright. All rights reserved. Environment Agency, 100026380, 2017.

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).