water situation report - assets.publishing.service.gov.uk...all data are provisional and may be...

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 2020

Monthly water situation report

Summary – February 2020 As a result of Storms Ciara, Dennis and Jorge, Thames Area received two and a half times the average rainfall for February, resulting in all units in the Thames Area being classed as notably high or exceptionally high for the time of year. This was the sixth month in a row of above average rainfall. The majority of the rivers we report on were classed as notably high for the time of year, while most groundwater sites were notably high or exceptionally high. For the fourth month in a row the Soil Moisture Deficit remained at zero in all catchments.

Rainfall As a result of Storms Ciara, Dennis and Jorge, February was a particularly wet month. The Thames Area received a total 120mm of rainfall in February, which is 252% of the Long Term Average (LTA), leading all units to be classed as either notably high or exceptionally high for the time of year. In the south of the Thames Area the Lower Wey and Wey Greensand received 288% of their LTA rainfall for February, this was the 3rd and 4th wettest February respectively for these units since 1910. Just under half the month’s rain fell over four separate days; 9, 12, 15 and 28 February. On the wettest day, 15 February, Bordon and East Worldham raingauges in the Wey Greensand received a daily total of 37.5mm and 32.9mm respectively.

Soil Moisture Deficit/Recharge February’s rainfall meant that the Soil Moisture Deficit (SMD) for the Thames Area was 0mm for the fourth month in a row, leading to soils being wetter than expected for the time of year. With fully saturated soils, effective rainfall was nearly 300% of the LTA for February. The Wey Greensand received 148mm of effective rainfall, this was three and a half times of what is expected for this time of year. After a 6th consecutive month of above average rainfall, Thames Area has received 200% of the expected effective rainfall for the winter period so far.

River Flows With fully wetted soils across the Thames Area, rivers responded quickly to the rainfall during February and the majority of our indicator sites recorded notably high or higher monthly mean flows for the time of year. In the south of the Thames Area, two sites, Tilford on the Upper River Wey and Swallowfield on the River Blackwater both had exceptionally high flow. At Tilford, exceptionally high groundwater levels in the chalk at Tile Barn Farm combined with exceptionally high rainfall to create exceptionally high flows. In contrast, in the flashier clay dominated River Blackwater catchment, the river reacted quickly to heavy rainfall to produce exceptionally high flows at Swallowfield.

Groundwater Levels By month end, all but one of the indicator sites had risen as compared to last month and the majority were classed as notably high or exceptionally high. Groundwater levels of the Oolitic limestones have increased reaching exceptionally high at one key monitoring site (Ampney Crucis). Groundwater levels at all indicator sites in the Chalk are notably high or exceptionally high, apart from the slower reacting Stonor Park, which remained normal for the time of year. Groundwater levels of the Greensands have also increased reaching

notably high at two of the key sites.

Environmental Impact There were 82 fluvial Flood Alerts issued on rivers during February and 29 Flood Warnings. By month end, there were seven groundwater Flood Alerts in force, four of which were issued in February. At the end of the month there were no flow constraints in place on abstractions, because river flows remained high enough that abstraction did not need to be restricted in order to protect the environment. Author: Thames Area Groundwater Resources and Hydrology Team Contact details: 02030259659 [email protected]

Thames Area

mailto:[email protected]



Rainfall Map (1)

Total rainfall for hydrological areas across Thames Area for the current month (up to 29 February) 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, 2020). Provisional data based on Environment Agency 1km gridded rainfall dataset derived from Environment Agency intensity rain gauges. Crown copyright. All rights reserved. Environment Agency, 100024198, 2020.



Rainfall Map (2)

Total rainfall for hydrological areas across Thames Area for the current month (up to 29 February), the last 3 months, the last 6 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, 2020). Provisional data based on Environment Agency 1km gridded rainfall dataset derived from Environment Agency intensity rain gauges. Crown copyright. All rights reserved. Environment Agency, 100024198, 2020.



River Flow and Groundwater Status Map

Groundwater site status based on end of month level. Surface water site status based on mean monthly 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, 100024198, 2020. Geological map reproduced with kind permission from UK Groundwater Forum, BGS © NERC



Rainfall, effective rainfall and river flow (1) Cotswolds West and River Coln Cotswolds East and River Evenlode Monthly total rainfall (mm) Long term average rainfall (mm)

Exceptionally high Notably high Above normal Normal Below normal Notably low Exceptionally low ─── Latest data

0

20

40

60

80

100

120

140

160

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

Cotswolds West - Rainfall

0

20

40

60

80

100

120

140

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

Cotswolds East - Rainfall

0

20

40

60

80

100

120

140

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)

Cotswolds West - Effective Rainfall

0

20

40

60

80

100

120

140

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)

Cotswolds East - Effective Rainfall

0

1

2

3

4

5

6

29-Apr-19 29-Jun-19 29-Aug-19 29-Oct-19 29-Dec-19 29-Feb-20

Dail

y M

ean

Flo

w (

cu

mecs)

RIVER COLN AT BIBURYRanking used data from 01/10/1963 to 31/12/2017

0

5

10

15

20

25

30


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER EVENLODE AT CASSINGTONRanking used data from 01/10/1970 to 31/12/2017



Rainfall, effective rainfall and river flow (2) Cherwell catchment and River Cherwell Upper Thames catchment and upper River Thames Monthly total rainfall (mm) Long term average rainfall (mm)


0

20

40

60

80

100

120

140

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

Cherwell - Rainfall

0

20

40

60

80

100

120

140

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

Upper Thames - Rainfall

0

20

40

60

80

100

120

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)

Cherwell - Effective Rainfall

0

20

40

60

80

100

120

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)Upper Thames - Effective Rainfall

0

5

10

15

20

25

30


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER CHERWELL AT BANBURYRanking used data from 01/01/1972 to 31/12/2017

0

10

20

30

40

50

60

70

80


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER THAMES AT FARMOOR (NATURALISED)Ranking used data from 01/10/1992 to 31/12/2017



Rainfall, effective rainfall and river flow (3) Thame catchment and River Thame Ock catchment and River Ock Monthly total rainfall (mm) Long term average rainfall (mm)


0

20

40

60

80

100

120

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

Thame - Rainfall

0

20

40

60

80

100

120

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

Ock - Rainfall

0

10

20

30

40

50

60

70

80

90

100

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)

Thame - Effective Rainfall

0

10

20

30

40

50

60

70

80

90

100

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)

Ock - Effective Rainfall

0

5

10

15

20

25

30

35


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER THAME AT WHEATLEYRanking used data from 01/01/1990 to 31/12/2017

0

2

4

6

8

10

12

14


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER OCK AT ABINGDONRanking used data from 01/06/1979 to 31/12/2017



Rainfall, effective rainfall and river flow (4) Berkshire Downs and River Kennet Chilterns West and River Wye Monthly total rainfall (mm) Long term average rainfall (mm)


0

20

40

60

80

100

120

140

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

Berkshire Downs - Rainfall

0

20

40

60

80

100

120

140

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

Chilterns West - Rainfall

0

20

40

60

80

100

120

140

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)

Berkshire Downs - Effective Rainfall

0

20

40

60

80

100

120

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)

Chilterns West - Effective Rainfall

0

5

10

15

20

25

30

35

01-Mar-18 01-May-18 01-Jul-18 01-Sep-18 01-Nov-18 01-Jan-19 01-Mar-19

Dail

y M

ean

Flo

w (

cu

mecs)

RIVER KENNET AT THEALERanking used data from 01/10/1961 to 31/12/2017

0

1

1

2

2

3


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER WYE AT BOURNE END (HEDSOR)Ranking used data from 01/01/1965 to 31/12/2017

Please note: No data available for Theale

since June as performance of the gauge is

impaired.



Rainfall, effective rainfall and river flow (5) Loddon catchment and River Loddon North Downs (Hampshire) and Blackwater Monthly total rainfall (mm) Long term average rainfall (mm)


0

20

40

60

80

100

120

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

Loddon - Rainfall

0

20

40

60

80

100

120

140

160

180

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

North Downs Hampshire - Rainfall

0

20

40

60

80

100

120

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)

Loddon - Effective Rainfall

0

20

40

60

80

100

120

140

160

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)North Downs Hampshire - Effective Rainfall

0

2

4

6

8

10

12

14

16

18

20


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER LODDON AT SHEEPBRIDGERanking used data from 01/10/1965 to 31/12/2017

0

5

10

15

20

25


Dail

y M

ean

Flo

w (

cu

mecs)

BLACKWATER AT SWALLOWFIELDRanking used data from 01/10/1952 to 31/12/2017



Rainfall, effective rainfall and river flow (6) Wey (Greensand) and Lower Wey catchment and upper River Wey lower River Wey Monthly total rainfall (mm) Long term average rainfall (mm)


0

20

40

60

80

100

120

140

160

180

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

Wey Greensand - Rainfall

0

20

40

60

80

100

120

140

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

No

v-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Rain

fall (

mm

)

Lower Wey - Rainfall

0

20

40

60

80

100

120

140

160

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)

Wey Greensand - Effective Rainfall

0

20

40

60

80

100

120

Mar-1

9

Apr-1

9

May-1

9

Jun-1

9

Jul-1

9

Aug-1

9

Sep-1

9

Oct-1

9

Nov-1

9

Dec-1

9

Jan-2

0

Feb-2

0

Eff

ecti

ve R

ain

fall (

mm

)Lower Wey - Effective Rainfall

0

5

10

15

20

25

30

35


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER WEY AT TILFORDRanking used data from 01/01/1973 to 31/12/2017

0

10

20

30

40

50

60

70


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER WEY AT GUILDFORDRanking used data from 23/02/1996 to 31/12/2017



River Thames


0

10

20

30

40

50

60

70

80


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER THAMES AT FARMOOR (NATURALISED)Ranking used data from 01/10/1992 to 31/12/2017

0

50

100

150

200

250

300


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER THAMES AT WINDSORRanking used data from 01/08/1979 to 31/12/2017

0

50

100

150

200

250

300

350

400

450

500


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER THAMES AT KINGSTON (NATURALISED)Ranking used data from 01/01/1951 to 31/12/2017

0

50

100

150

200

250

300

350

400

450


Dail

y M

ean

Flo

w (

cu

mecs)

RIVER THAMES AT KINGSTONRanking used data from 01/01/1951 to 31/12/2017



Groundwater Levels

99

100

100

101

101

102

102

103

103

104

104

May-18 Aug-18 Nov-18 Feb-19 May-19 Aug-19 Nov-19 Feb-20

Level (m

AO

D)

AMPNEY CRUCIS - GREAT OOLITERanking derived from data for the period Dec-1958 to Dec-2017

94

95

95

96

96

97

97

98

98

99

99


Level (m

AO

D)

FRINGFORD - GREAT OOLITERanking derived from data for the period Sep-1980 to Dec-2017

94

96

98

100

102

104

106


Level (m

AO

D)

JACKAMENTS BOTTOM - INFERIOR OOLITERanking derived from data for the period Jan-1974 to Dec-2017

58.0

58.2

58.4

58.6

58.8

59.0

59.2

59.4

59.6

59.8

60.0


Level (m

AO

D)

MARCHAM - CORALLIANRanking derived from data for the period Jan-1988 to Dec-2017

105

110

115

120

125

130


Level (m

AO

D)

GIBBET COTTAGES - CHALKRanking derived from data for the period Jul-1973 to Dec-2017

62

67

72

77

82

87


Level (m

AO

D)

STONOR PARK- CHALKRanking derived from data for the period May-1961 to Dec-2017

128

130

132

134

136

138

140

142

144


Level (m

AO

D)

ROCKLEY - CHALKRanking derived from data for the period Mar-1933 to Dec-2017

85

86

87

88

89

90

91

92

93

94

95


Level (m

AO

D)

TILE BARN FARM - CHALKRanking derived from data for the period Oct-1971 to Dec-2017



Groundwater Levels


94

95

96

97

98

99

100


Level (m

AO

D)

FRITH COTTAGE - LOWER GREENSAND (HYTHE)Ranking derived from data for the period Jul-1970 to Dec-2017

56.0

56.5

57.0

57.5

58.0

58.5

59.0

59.5

60.0


Level (m

AO

D)

FLASHES - LOWER GREENSAND (FOLKESTONE)Ranking derived from data for the period Apr-1993 to Dec-2017

89

90

91

92

93

94

95

96

97

98

99


Level (m

AO

D)

MODEL FARM - UPPER GREENSANDRanking derived from data for the period Feb-1963 to Dec-2017



End of month flow constraints

Summary of flow constraints

Week ending 02/02/2020 09/02/2020 16/02/2020 23/02/2020

Number of flow constraints in force 0 0 0 0



Summary of rainfall, effective rainfall and soil moisture deficit Rainfall and effective rainfall Rainfall (mm) Effective Rainfall (mm)

Area 29 day total

February LTA

% LTA 29 day total

February LTA

% LTA

Cotswolds West 145 57 252 131 43 309

Cotswolds East 112 48 232 99 36 274

Berkshire Downs 130 52 249 117 39 300

Chilterns West 115 47 242 101 36 278

North Downs Hampshire 159 59 269 146 51 288

Wey - Greensand 161 56 288 148 43 347

Upper Thames 116 45 255 102 35 291

Cherwell 103 45 231 89 35 255

Thame 95 41 235 82 29 279

Loddon 114 44 256 100 33 308

Lower Wey 120 42 288 106 32 334

Ock 93 41 229 79 30 265

Enborne 125 51 245 112 40 282

Cut 98 40 247 84 29 286

Thames Area 120 48 252 107 36 294

Soil moisture deficit SMD (mm)

Area End

February

End February

LTA

Cotswolds West 0 3

Cotswolds East 0 3

Berkshire Downs 0 3

Chilterns West 0 2

North Downs Hampshire 0 2

Wey - Greensand 0 3

Upper Thames 0 4

Cherwell 0 2

Thame 0 2

Loddon 0 3

Lower Wey 0 3

Ock 0 4

Enborne 0 3

Cut 0 3

Thames Area 0 3



Winter rainfall and effective rainfall

Winter period: 01/10/2019 to 29/02/2020

Rainfall (mm) Effective Rainfall (mm)

Area total LTA % LTA total LTA % LTA

Cotswolds West 603 359 168 552 255 216

Cotswolds East 522 308 169 448 206 218

Berkshire Downs 547 348 157 442 217 204

Chilterns West 490 321 152 360 207 174

North Downs Hampshire 632 406 156 540 319 169

Wey - Greensand 639 391 164 537 256 210

Upper Thames 498 300 166 395 178 222

Cherwell 473 288 164 378 184 205

Thame 440 274 161 324 153 212

Loddon 474 309 153 351 183 192

Lower Wey 485 297 163 355 181 196

Ock 437 270 162 310 137 226

Enborne 537 342 157 435 218 199

Cut 418 283 148 284 158 180

Thames Area 514 321 160 408 204 200

This is a second estimate of areal rainfall, effective rainfall (i.e. percolation/runoff) and soil moisture deficit. There may be significant variation within each area which must be considered when interpreting these data. When additional meteorological data is available estimates are revised, this will affect period totals.



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).

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

LIT 9042

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