Water Situation Report
Monthly water situation report South East England Summary – September 2017 The south-east of England received close to average rainfall for September, with 104% of the long term average. By the end of the month, the soil moisture deficits were close to the long term average. Recharge was about half what would be expected during September. River flows had a muted response to the rainfall during the month owing to the high soil moisture deficits and groundwater levels have continued their seasonal decline.
Rainfall The south-east of England received close to average rainfall for September, with 104% of the long term average (LTA). There were 5 days when relatively heavy rainfall fell, with the wettest, the 3rd, the 8th and the 27th accounting for approximately 36% of the monthly total. The 5 highest daily rainfall totals across the south east all occurred in Solent and South Downs (SSD) on the 3rd and 8th, with the highest daily total (37.2 mm) recorded at Calbourne (Isle of Wight) on the 3rd. However, on average, a third of the month was dry with raingauges recording less than 0.2mm in a day. September marked the end of a relatively dry water year. It was the driest 12 months ending in September since 1989 for Chilterns West (Thames Area, THM); and the Stour and Darent (both Kent and South London, KSL). It was the driest year since 2005 for a number of units towards the south, including West Sussex Chalk (SSD) and North Downs, Hampshire (THM). However, for most of the units across the south-east it was the driest water year since 2011, including Lee Chalk and Roding (Hertfordshire and North London, HNL); Cotswolds West (THM), Test Chalk (SSD) and Upper Mole (KSL).
Soil Moisture Deficit/Recharge The soil moisture deficits (SMDs) peaked about the 7th of September, then dropped in response to the rainfall on the 8th and 27th to end the month close to the LTA. Recharge was about half what would be expected during September owing to the high SMDs during most of the month and was just below half the LTA for the period April to September.
River Flows River flows had a muted response to the rainfall during the month owing to the high SMDs. The seasonal recession of flows continued at most of the indicator sites. The River Mimram at Panshanger and the River Ver at Colney Street (both HNL) had notably low flows during September, reflecting the local groundwater levels. The Ver had the lowest September flows since 2006. The River Dour at Crabble Mill (KSL) had the lowest September flows since 1997. Only one flood alert was issued during September: HNL
THM
SSD
KSL
Total
Fluvial Flood Alerts
0
1
0
0
1
Fluvial Flood Warnings
0
0
0
0
0
Groundwater Levels Groundwater levels continued the seasonal decline expected at this time of year and were at normal levels during the month or lower. The lowest levels were generally recorded in the Chilterns and North Downs. Ashley Green (HNL) continued to have exceptionally low levels and had the lowest September levels on record (from 1987). Lilley Bottom (HNL) had the lowest September level since 2006 and Little Bucket (KSL) had the lowest level since 1996.
Reservoir Storage/Water Resource Zone Stocks Reservoir storage remains above the LTA for most of the reservoirs across the south-east of England with the exceptions of Lower Thames (HNL), Bewl and Darwell (KSL). Author: Groundwater, Hydrology and Contaminated Land Team, Hertfordshire & North London 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 2017
Rainfall Map
Total rainfall for hydrological areas across 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. Data source: Rainfall from South East Soil Moisture Model. 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, 2017.
www.gov.uk/environment-agency
© Environment Agency 2017
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, 100026380, 2017 Geological map reproduced with kind permission from UK Groundwater Forum, BGS © NERC
www.gov.uk/environment-agency
© Environment Agency 2017
Thames – Page 1 Monthly total rainfall (mm)
Long term average rainfall (mm) Berkshire Downs (G) - Rainfall
120
120
100
100
80
80
Rainfall (mm)
Rainfall (mm)
Cotswolds - West (A) - Rainfall
60
40
60
40
Effective Rainfall (mm)
Effective Rainfall (mm)
50 40 30 20
50 40 30 20
10
10
0
0 Sep-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
RIVER COLN AT BIBURY
RIVER KENNET AT THEALE
Ranking derived from data for the period 01/10/1961 to 31/12/2012
Ranking derived from data for the period 01/10/1961 to 31/12/2012
4.5
35
4.0
30
3.5
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
Sep-17
60
60
Jan-17
Aug-17
70
Dec-16
Aug-17
70
Nov-16
Jul-17
Berkshire Downs (G) - Effective Rainfall
80
Oct-16
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Cotswolds - West (A) - Effective Rainfall
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
0
Dec-16
0
Nov-16
20
Oct-16
20
3.0 2.5 2.0 1.5 1.0 0.5 0.0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
25
20
15
10
5
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER THAMES AT EYNSHAM Ranking derived from data for the period 01/01/1955 to 31/12/2012
80
Daily Mean Flow (cumecs)
70 60
50 40 30 20
Data from Farmoor gauging station during June 2017.
10 0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Thames – Page 2 Monthly total rainfall (mm)
Long term average rainfall (mm)
North Downs - Hampshire (P) - Rainfall
Wey - Greensand (S) - Rainfall
100
100
80
80
Rainfall (mm)
120
Rainfall (mm)
120
60
40
60
40
20
20
0
0 Aug-17
Jul-17
Aug-17
Sep-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
North Downs - Hampshire (P) - Effective Rainfall
Wey - Greensand (S) - Effective Rainfall
100
80
90
70
Effective Rainfall (mm)
Effective Rainfall (mm)
80 70 60 50 40 30 20
60 50 40 30 20 10
10 0
0 Sep-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
RIVER WEY AT TILFORD
RIVER LODDON AT SHEEPBRIDGE
Ranking derived from data for the period 01/01/1973 to 31/12/2012
Ranking derived from data for the period 01/10/1965 to 31/12/2012
14
10 9
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
12
10
8
6
4
2
8 7
6 5 4 3 2
1 0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER THAMES AT KINGSTON (NATURALISED) Ranking derived from data for the period 01/01/1883 to 31/12/2012
350
Daily Mean Flow (cumecs)
300
250
200
150
100
50
0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Hertfordshire and North London Monthly total rainfall (mm)
Long term average rainfall (mm)
Chilterns - East - Colne (N) - Rainfall
Lee - Chalk - Rainfall
100
90
90
80
80
70 60
60
Rainfall (mm)
Rainfall (mm)
70
50 40 30
50 40 30 20
20 10
10
0
0 Aug-17
Jul-17
Aug-17
Sep-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Chilterns - East - Colne (N) - Effective Rainfall
Lee - Chalk - Effective Rainfall
70
50 45
60
Effective Rainfall (mm)
Effective Rainfall (mm)
40 50 40 30 20
35 30 25 20 15 10
10 5 0
0
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
0.8
0.6
0.4
0.2
31-Jul-17
30-Sep-17
Sep-17
1.0
31-May-17
Jun-17
1.2
31-Mar-17
May-17
1.2
31-Jan-17
Apr-17
RIVER MIMRAM AT PANSHANGER Ranking derived from data for the period 01/12/1952 to 31/12/2012
1.4
0.0 30-Nov-16
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
RIVER VER AT COLNEY STREET (HANSTEADS) Ranking derived from data for the period 01/10/1956 to 31/12/2012
1.4
30-Nov-17
1.0
0.8
0.6
0.4
0.2
0.0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER LEE AT FEILDES WEIR (Naturalised) Ranking derived from data for the period 01/10/1883 to 31/12/2012
30
Daily Mean Flow (cumecs)
25
20
15
10
5
0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Solent & South Downs – Page 1 Monthly total rainfall (mm)
Long term average rainfall (mm) Lymington - Rainfall
Test Chalk - Rainfall 140
120
120
100
100
Rainfall (mm)
Rainfall (mm)
80
80 60 40
60
40
20
20 0
0
Effective Rainfall (mm)
Effective Rainfall (mm)
Sep-17
60 50 40 30 20
70 60 50 40 30 20
10
10
0
0 Sep-17
Jun-17
May-17
Apr-17
LYMINGTON RIVER AT BROCKENHURST
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Aug-17
80
Dec-16
Aug-17
70
Nov-16
Jul-17
90
Oct-16
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Lymington - Effective Rainfall
Test Chalk - Effective Rainfall 80
RIVER TEST AT BROADLANDS
Ranking derived from data for the period 01/01/1997 to 31/12/2012
Ranking derived from data for the period 01/10/1957 to 31/12/2012
16
30
14
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
25 12
10 8 6 4
20
15
10
5
2 0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER ITCHEN AT ALLBROOK AND HIGHBRIDGE Ranking derived from data for the period 01/10/1958 to 31/12/2012
14
Daily Mean Flow (cumecs)
12
10
8
6
4
2
0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Solent & South Downs – Page 2 Monthly total rainfall (mm)
Long term average rainfall (mm) Ouse - Rainfall
Arun - Rainfall
100
100
80
80
Rainfall (mm)
120
Rainfall (mm)
120
60
40
60
40
20
20
0
0
80
90
80
70
Effective Rainfall (mm)
Effective Rainfall (mm)
Aug-17
Ouse - Effective Rainfall 100
60 50 40 30 20
70 60 50 40 30 20
10
10
0
0 Sep-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
RIVER ROTHER AT IPING MILL
RIVER ARUN AT ALFOLDEAN
Ranking derived from data for the period 01/11/1966 to 31/12/2012
Ranking derived from data for the period 01/05/1970 to 31/12/2012
12
25
Daily Mean Flow (cumecs)
10
Daily Mean Flow (cumecs)
Aug-17
Jul-17
Sep-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Arun - Effective Rainfall 90
8
6
4
2
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
20
15
10
5
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER OUSE AT GOLDBRIDGE Ranking derived from data for the period 01/10/1992 to 31/12/2012
20
Daily Mean Flow (cumecs)
18 16 14
12 10 8 6 4
2 0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Kent & South London – Page 1 Monthly total rainfall (mm)
Long term average rainfall (mm) Eastern Rother - Rainfall
Medway - Rainfall 120
140
120
100
100
Rainfall (mm)
Rainfall (mm)
80
60
40
20
80 60 40 20
0
0
Effective Rainfall (mm)
Effective Rainfall (mm)
50 40 30 20
70 60 50 40 30 20
10
10
0
0 Sep-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
RIVER MEDWAY AT TESTON & EAST FARLEIGH COMBINED
RIVER TEISE AT STONEBRIDGE
Ranking derived from data for the period 01/10/1956 to 31/12/2012
Ranking derived from data for the period 01/10/1961 to 31/12/2012
100
10
90
9
80
8
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
Sep-17
60
Jan-17
Aug-17
80
Dec-16
Aug-17
70
Nov-16
Jul-17
90
Oct-16
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Eastern Rother - Effective Rainfall
Medway - Effective Rainfall 80
70
60 50 40 30 20
10
7
6 5 4 3 2
1
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER ROTHER AT UDIAM Ranking derived from data for the period 01/10/1962 to 31/12/2012
Daily Mean Flow (cumecs)
25
20
15
10
5
0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Kent & South London – Page 2 Monthly total rainfall (mm)
Long term average rainfall (mm)
Darent - Rainfall
Stour - Rainfall
100
100
80
80
Rainfall (mm)
120
Rainfall (mm)
120
60
40
60
40
20
20
0
0
Aug-17
Sep-17
Aug-17
Jun-17
Jul-17
Jun-17
May-17
Jul-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Stour - Effective Rainfall
Darent - Effective Rainfall 45
60
40
Effective Rainfall (mm)
Effective Rainfall (mm)
50 35 30 25 20 15 10
40
30
20
10
5
0
0 Sep-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
RIVER DARENT AT HAWLEY
GREAT STOUR AT HORTON
Ranking derived from data for the period 01/12/1963 to 31/12/2012
Ranking derived from data for the period 01/10/1964 to 31/12/2012
3.0
16
14
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
2.5
2.0
1.5
1.0
0.5
12
10 8 6 4 2
0.0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
0 30-Nov-16
30-Nov-17
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER DOUR AT CRABBLE MILL Ranking derived from data for the period 06/01/1976 to 31/12/2012
1.6
Daily Mean Flow (cumecs)
1.4 1.2
1.0 0.8 Data under investigation.
0.6 0.4 0.2 0.0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Groundwater Levels Exceptionally high Below normal
Notably high Notably low
Above normal Exceptionally low
Normal ─── Latest data
CHILTERNS WEST - STONOR PARK - CHALK Ranking derived from data for the period May-1961 to Dec-2012
87 106 82
Level (mAOD)
Level (mAOD)
104 102 100 98
72 67
96
94 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
62 Dec-15 Mar-16 Jun-16
Sep-17
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
MARLBOROUGH DOWNS - ROCKLEY - CHALK
NORTH DOWNS - TILE BARN FARM - CHALK
Ranking derived from data for the period Mar-1933 to Dec-2012
Ranking derived from data for the period Oct-1971 to Dec-2012
144
93
142
92
140
91
Level (mAOD)
Level (mAOD)
77
138 136 134
90 89 88
132
87
130
86
128 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
85 Dec-15 Mar-16 Jun-16
Sep-17
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
CHILTERNS EAST - ASHLEY GREEN - CHALK
LEE CHALK WEST - LILLEY BOTTOM - CHALK
Ranking derived from data for the period Sep-1987 to Dec-2012
Ranking derived from data for the period Jul-1979 to Dec-2012
99
129
Level (mAOD)
Level (mAOD)
98 124
119
114
97 96 95
94 93
109 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
92 Dec-15 Mar-16 Jun-16
Sep-17
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
HAMPSHIRE DOWNS - CLANVILLE LODGE - CHALK
HAMPSHIRE DOWNS - LOPCOMBE CORNER - CHALK
Ranking derived from data for the period Mar-1963 to Dec-2012
Ranking derived from data for the period Apr-1963 to Dec-2012
95 90
93 91
86
Level (mAOD)
Level (mAOD)
88
84 82 80
89 87 85 83
78
81
76
79
74 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
www.gov.uk/environment-agency
Sep-17
77 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
© Environment Agency 2017
Groundwater Levels Notably high Notably low
Above normal Exceptionally low
ISLE OF WIGHT - CARISBROOKE CASTLE - CHALK
SOUTH DOWNS - WEST MEON - CHALK Ranking derived from data for the period Sep-1986 to Dec-2012
32
94
31
92
30
90
29 28 27
88 86 84 82
26
80
25
78
24 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
76 Dec-15 Mar-16 Jun-16
Sep-17
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
SOUTH DOWNS - HOUNDEAN BOTTOM - CHALK
NORTH DOWNS - CHIPSTEAD - CHALK
Ranking derived from data for the period Jan-1977 to Dec-2012
Ranking derived from data for the period Oct-1942 to Dec-2012
24
101 99
Level (mAOD)
19
Level (mAOD)
Normal ─── Latest data
Ranking derived from data for the period Aug-1977 to Dec-2012
Level (mAOD)
Level (mAOD)
Exceptionally high Below normal
14 9
97 95 93 91 89
4
87 Sep-16 Dec-16 Mar-17 Jun-17
85 Dec-15 Mar-16 Jun-16
Sep-17
Sep-17
NORTH DOWNS - SWEEPS LANE - CHALK
NORTH DOWNS - RIDDLES LANE - CHALK Ranking derived from data for the period Apr-1982 to Dec-2012
46
25
46
23
45 45 44 44
21 19 17
15 13
43 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
11 Dec-15 Mar-16 Jun-16
Sep-17
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
NORTH DOWNS - LITTLE BUCKET - CHALK
CHILGROVE HOUSE GWL
Ranking derived from data for the period Jan-1971 to Dec-2012
Ranking derived from data for the period Feb-1836 to Dec-2012
87
75 70
Level (mAOD)
82
Level (mAOD)
Sep-16 Dec-16 Mar-17 Jun-17
Ranking derived from data for the period Jan-1984 to Dec-2012
Level (mAOD)
Level (mAOD)
-1 Dec-15 Mar-16 Jun-16
77 72 67
65
60 55 50 45
62
57 Dec-15 Mar-16 Jun-16
40
Sep-16 Dec-16 Mar-17 Jun-17
www.gov.uk/environment-agency
Sep-17
35 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
© Environment Agency 2017
Reservoir Stocks 2003
LTA
MIN
2013
2016
2017
2003
Thames Water - Lower Thames Reservoirs - Lower Thames
LTA
MIN
2013
2016
2017
Thames Water - Lee Valley Reservoirs - Lower Lee
100
Percentage of live capacity
Percentage of live capacity
100 80
60
40
20
0
80
60
40
20
0 Jan Feb Mar Apr May Jun 2003
LTA
Jul
Aug Sep Oct Nov Dec
MIN
2013
2016
Jan Feb Mar Apr May Jun
2017
LTA
Thames Water - Farmoor Reservoir - Upper Thames
Percentage of live capacity
Percentage of live capacity
2013
2016
2017
100
80
60
40
20
0
80
60
40
20
0 Jan Feb Mar Apr May Jun LTA
MIN
Jul
Aug Sep Oct Nov Dec
2013
2016
Jan Feb Mar Apr May Jun
2017
LTA
South East Water - Ardingly Reservoir - Ouse
MIN
Jul
Aug Sep Oct Nov Dec
2013
2016
2017
South East Water - Arlington Reservoir - Cuckmere 100
Percentage of live capacity
100
Percentage of live capacity
Aug Sep Oct Nov Dec
Sutton & East Surrey Water - Bough Beech Reservoir Medway
100
80
60
40
20
0
80
60
40
20
0 Jan Feb Mar Apr May Jun LTA
MIN
Jul
Aug Sep Oct Nov Dec
2013
2016
Jan Feb Mar Apr May Jun LTA
2017
MIN
Jul
Aug Sep Oct Nov Dec
2013
2016
2017
Southern Water - Darwell Reservoir - Rother (Eastern)
Southern Water - Bewl Reservoir - Teise (Medway) 100
100 90
Percentage of live capacity
Percentage of live capacity
MIN
Jul
80 70 60
50 40 30 20
90 80 70 60 50 40 30 20 10
10 0
0 Jan Feb Mar Apr May Jun
www.gov.uk/environment-agency
Jul
Aug Sep Oct Nov Dec
Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
© Environment Agency 2017
Reservoir Stocks LTA
MIN
2013
2016
2017
LTA
Southern Water - Powdermill Reservoir - Brede
2013
2016
2017
100
Percentage of live capacity
100
Percentage of live capacity
MIN
Southern Water - Weir Wood Reservoir - Medway
80
60
40
20
80
60
40
20
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
Cumulative Rainfall Plots CUMULATIVE RAINFALL FOR HERTS AND NORTH LONDON AREA COMPARED WITH LONG TERM AVERAGE 2000
1500
1500
1000
Sep-17 Sep-17
Jul-17
Aug-17
Jun-17
Apr-17
May-17
Mar-17
Jan-17
Feb-17
Dec-16
Oct-16
Nov-16
Sep-16
Jul-16
Aug-16
Jun-16
Apr-16
May-16
Aug-17
CUMULATIVE RAINFALL FOR SOLENT AND SOUTH DOWNS AREA COMPARED WITH LONG TERM AVERAGE
Mar-16
Oct-15
Sep-17
Jul-17
Aug-17
Jun-17
Apr-17
May-17
Mar-17
Jan-17
Feb-17
Dec-16
Oct-16
Nov-16
Sep-16
Jul-16
Aug-16
Jun-16
Apr-16
May-16
Mar-16
Jan-16
0
Feb-16
0 Oct-15
500
Jan-16
Average
500
Feb-16
Average
1000
Dec-15
MILLIMETRES
2000
Dec-15
MILLIMETRES
CUMULATIVE RAINFALL FOR THAMES AREA COMPARED WITH LONG TERM AVERAGE
CUMULATIVE RAINFALL FOR KENT AND SOUTH LONDON AREA COMPARED WITH LONG TERM AVERAGE
2000
2000
1800 1500
1400
MILLIMETRES
MILLIMETRES
1600
1200
Average
1000 800
600
Average 1000
500
400 200
www.gov.uk/environment-agency
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-16
Aug-16
Jul-16
Jun-16
May-16
Apr-16
Mar-16
Jan-16
Feb-16
Oct-15
Dec-15
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-16
Aug-16
Jul-16
Jun-16
May-16
Apr-16
Mar-16
Jan-16
Feb-16
Oct-15
0 Dec-15
0
© Environment Agency 2017
www.gov.uk/environment-agency
© Environment Agency 2017
South East Areal Rainfall units for reference
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, 2017.
www.gov.uk/environment-agency
© Environment Agency 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 (m 3s-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 Notably high Above normal Normal Below normal Notably low Exceptionally low
Value likely to fall within this band 5% of the time Value likely to fall within this band 8% of the time Value likely to fall within this band 15% of the time Value likely to fall within this band 44% of the time Value likely to fall within this band 15% of the time Value likely to fall within this band 8% of the time Value likely to fall within this band 5% of the time
Cat code LIT 9025
www.gov.uk/environment-agency
© Environment Agency 2017
Rainfall The south-east of England received close to average rainfall for September, with 104% of the long term average (LTA). There were 5 days when relatively heavy rainfall fell, with the wettest, the 3rd, the 8th and the 27th accounting for approximately 36% of the monthly total. The 5 highest daily rainfall totals across the south east all occurred in Solent and South Downs (SSD) on the 3rd and 8th, with the highest daily total (37.2 mm) recorded at Calbourne (Isle of Wight) on the 3rd. However, on average, a third of the month was dry with raingauges recording less than 0.2mm in a day. September marked the end of a relatively dry water year. It was the driest 12 months ending in September since 1989 for Chilterns West (Thames Area, THM); and the Stour and Darent (both Kent and South London, KSL). It was the driest year since 2005 for a number of units towards the south, including West Sussex Chalk (SSD) and North Downs, Hampshire (THM). However, for most of the units across the south-east it was the driest water year since 2011, including Lee Chalk and Roding (Hertfordshire and North London, HNL); Cotswolds West (THM), Test Chalk (SSD) and Upper Mole (KSL).
Soil Moisture Deficit/Recharge The soil moisture deficits (SMDs) peaked about the 7th of September, then dropped in response to the rainfall on the 8th and 27th to end the month close to the LTA. Recharge was about half what would be expected during September owing to the high SMDs during most of the month and was just below half the LTA for the period April to September.
River Flows River flows had a muted response to the rainfall during the month owing to the high SMDs. The seasonal recession of flows continued at most of the indicator sites. The River Mimram at Panshanger and the River Ver at Colney Street (both HNL) had notably low flows during September, reflecting the local groundwater levels. The Ver had the lowest September flows since 2006. The River Dour at Crabble Mill (KSL) had the lowest September flows since 1997. Only one flood alert was issued during September: HNL
THM
SSD
KSL
Total
Fluvial Flood Alerts
0
1
0
0
1
Fluvial Flood Warnings
0
0
0
0
0
Groundwater Levels Groundwater levels continued the seasonal decline expected at this time of year and were at normal levels during the month or lower. The lowest levels were generally recorded in the Chilterns and North Downs. Ashley Green (HNL) continued to have exceptionally low levels and had the lowest September levels on record (from 1987). Lilley Bottom (HNL) had the lowest September level since 2006 and Little Bucket (KSL) had the lowest level since 1996.
Reservoir Storage/Water Resource Zone Stocks Reservoir storage remains above the LTA for most of the reservoirs across the south-east of England with the exceptions of Lower Thames (HNL), Bewl and Darwell (KSL). Author: Groundwater, Hydrology and Contaminated Land Team, Hertfordshire & North London 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 2017
Rainfall Map
Total rainfall for hydrological areas across 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. Data source: Rainfall from South East Soil Moisture Model. 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, 2017.
www.gov.uk/environment-agency
© Environment Agency 2017
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, 100026380, 2017 Geological map reproduced with kind permission from UK Groundwater Forum, BGS © NERC
www.gov.uk/environment-agency
© Environment Agency 2017
Thames – Page 1 Monthly total rainfall (mm)
Long term average rainfall (mm) Berkshire Downs (G) - Rainfall
120
120
100
100
80
80
Rainfall (mm)
Rainfall (mm)
Cotswolds - West (A) - Rainfall
60
40
60
40
Effective Rainfall (mm)
Effective Rainfall (mm)
50 40 30 20
50 40 30 20
10
10
0
0 Sep-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
RIVER COLN AT BIBURY
RIVER KENNET AT THEALE
Ranking derived from data for the period 01/10/1961 to 31/12/2012
Ranking derived from data for the period 01/10/1961 to 31/12/2012
4.5
35
4.0
30
3.5
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
Sep-17
60
60
Jan-17
Aug-17
70
Dec-16
Aug-17
70
Nov-16
Jul-17
Berkshire Downs (G) - Effective Rainfall
80
Oct-16
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Cotswolds - West (A) - Effective Rainfall
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
0
Dec-16
0
Nov-16
20
Oct-16
20
3.0 2.5 2.0 1.5 1.0 0.5 0.0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
25
20
15
10
5
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER THAMES AT EYNSHAM Ranking derived from data for the period 01/01/1955 to 31/12/2012
80
Daily Mean Flow (cumecs)
70 60
50 40 30 20
Data from Farmoor gauging station during June 2017.
10 0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Thames – Page 2 Monthly total rainfall (mm)
Long term average rainfall (mm)
North Downs - Hampshire (P) - Rainfall
Wey - Greensand (S) - Rainfall
100
100
80
80
Rainfall (mm)
120
Rainfall (mm)
120
60
40
60
40
20
20
0
0 Aug-17
Jul-17
Aug-17
Sep-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
North Downs - Hampshire (P) - Effective Rainfall
Wey - Greensand (S) - Effective Rainfall
100
80
90
70
Effective Rainfall (mm)
Effective Rainfall (mm)
80 70 60 50 40 30 20
60 50 40 30 20 10
10 0
0 Sep-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
RIVER WEY AT TILFORD
RIVER LODDON AT SHEEPBRIDGE
Ranking derived from data for the period 01/01/1973 to 31/12/2012
Ranking derived from data for the period 01/10/1965 to 31/12/2012
14
10 9
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
12
10
8
6
4
2
8 7
6 5 4 3 2
1 0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER THAMES AT KINGSTON (NATURALISED) Ranking derived from data for the period 01/01/1883 to 31/12/2012
350
Daily Mean Flow (cumecs)
300
250
200
150
100
50
0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Hertfordshire and North London Monthly total rainfall (mm)
Long term average rainfall (mm)
Chilterns - East - Colne (N) - Rainfall
Lee - Chalk - Rainfall
100
90
90
80
80
70 60
60
Rainfall (mm)
Rainfall (mm)
70
50 40 30
50 40 30 20
20 10
10
0
0 Aug-17
Jul-17
Aug-17
Sep-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Chilterns - East - Colne (N) - Effective Rainfall
Lee - Chalk - Effective Rainfall
70
50 45
60
Effective Rainfall (mm)
Effective Rainfall (mm)
40 50 40 30 20
35 30 25 20 15 10
10 5 0
0
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
0.8
0.6
0.4
0.2
31-Jul-17
30-Sep-17
Sep-17
1.0
31-May-17
Jun-17
1.2
31-Mar-17
May-17
1.2
31-Jan-17
Apr-17
RIVER MIMRAM AT PANSHANGER Ranking derived from data for the period 01/12/1952 to 31/12/2012
1.4
0.0 30-Nov-16
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
RIVER VER AT COLNEY STREET (HANSTEADS) Ranking derived from data for the period 01/10/1956 to 31/12/2012
1.4
30-Nov-17
1.0
0.8
0.6
0.4
0.2
0.0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER LEE AT FEILDES WEIR (Naturalised) Ranking derived from data for the period 01/10/1883 to 31/12/2012
30
Daily Mean Flow (cumecs)
25
20
15
10
5
0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Solent & South Downs – Page 1 Monthly total rainfall (mm)
Long term average rainfall (mm) Lymington - Rainfall
Test Chalk - Rainfall 140
120
120
100
100
Rainfall (mm)
Rainfall (mm)
80
80 60 40
60
40
20
20 0
0
Effective Rainfall (mm)
Effective Rainfall (mm)
Sep-17
60 50 40 30 20
70 60 50 40 30 20
10
10
0
0 Sep-17
Jun-17
May-17
Apr-17
LYMINGTON RIVER AT BROCKENHURST
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Aug-17
80
Dec-16
Aug-17
70
Nov-16
Jul-17
90
Oct-16
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Lymington - Effective Rainfall
Test Chalk - Effective Rainfall 80
RIVER TEST AT BROADLANDS
Ranking derived from data for the period 01/01/1997 to 31/12/2012
Ranking derived from data for the period 01/10/1957 to 31/12/2012
16
30
14
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
25 12
10 8 6 4
20
15
10
5
2 0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER ITCHEN AT ALLBROOK AND HIGHBRIDGE Ranking derived from data for the period 01/10/1958 to 31/12/2012
14
Daily Mean Flow (cumecs)
12
10
8
6
4
2
0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Solent & South Downs – Page 2 Monthly total rainfall (mm)
Long term average rainfall (mm) Ouse - Rainfall
Arun - Rainfall
100
100
80
80
Rainfall (mm)
120
Rainfall (mm)
120
60
40
60
40
20
20
0
0
80
90
80
70
Effective Rainfall (mm)
Effective Rainfall (mm)
Aug-17
Ouse - Effective Rainfall 100
60 50 40 30 20
70 60 50 40 30 20
10
10
0
0 Sep-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
RIVER ROTHER AT IPING MILL
RIVER ARUN AT ALFOLDEAN
Ranking derived from data for the period 01/11/1966 to 31/12/2012
Ranking derived from data for the period 01/05/1970 to 31/12/2012
12
25
Daily Mean Flow (cumecs)
10
Daily Mean Flow (cumecs)
Aug-17
Jul-17
Sep-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Arun - Effective Rainfall 90
8
6
4
2
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
20
15
10
5
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER OUSE AT GOLDBRIDGE Ranking derived from data for the period 01/10/1992 to 31/12/2012
20
Daily Mean Flow (cumecs)
18 16 14
12 10 8 6 4
2 0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Kent & South London – Page 1 Monthly total rainfall (mm)
Long term average rainfall (mm) Eastern Rother - Rainfall
Medway - Rainfall 120
140
120
100
100
Rainfall (mm)
Rainfall (mm)
80
60
40
20
80 60 40 20
0
0
Effective Rainfall (mm)
Effective Rainfall (mm)
50 40 30 20
70 60 50 40 30 20
10
10
0
0 Sep-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
RIVER MEDWAY AT TESTON & EAST FARLEIGH COMBINED
RIVER TEISE AT STONEBRIDGE
Ranking derived from data for the period 01/10/1956 to 31/12/2012
Ranking derived from data for the period 01/10/1961 to 31/12/2012
100
10
90
9
80
8
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
Sep-17
60
Jan-17
Aug-17
80
Dec-16
Aug-17
70
Nov-16
Jul-17
90
Oct-16
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Eastern Rother - Effective Rainfall
Medway - Effective Rainfall 80
70
60 50 40 30 20
10
7
6 5 4 3 2
1
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER ROTHER AT UDIAM Ranking derived from data for the period 01/10/1962 to 31/12/2012
Daily Mean Flow (cumecs)
25
20
15
10
5
0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Kent & South London – Page 2 Monthly total rainfall (mm)
Long term average rainfall (mm)
Darent - Rainfall
Stour - Rainfall
100
100
80
80
Rainfall (mm)
120
Rainfall (mm)
120
60
40
60
40
20
20
0
0
Aug-17
Sep-17
Aug-17
Jun-17
Jul-17
Jun-17
May-17
Jul-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Stour - Effective Rainfall
Darent - Effective Rainfall 45
60
40
Effective Rainfall (mm)
Effective Rainfall (mm)
50 35 30 25 20 15 10
40
30
20
10
5
0
0 Sep-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
RIVER DARENT AT HAWLEY
GREAT STOUR AT HORTON
Ranking derived from data for the period 01/12/1963 to 31/12/2012
Ranking derived from data for the period 01/10/1964 to 31/12/2012
3.0
16
14
Daily Mean Flow (cumecs)
Daily Mean Flow (cumecs)
2.5
2.0
1.5
1.0
0.5
12
10 8 6 4 2
0.0 30-Nov-16
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
0 30-Nov-16
30-Nov-17
31-Jan-17
31-Mar-17
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
RIVER DOUR AT CRABBLE MILL Ranking derived from data for the period 06/01/1976 to 31/12/2012
1.6
Daily Mean Flow (cumecs)
1.4 1.2
1.0 0.8 Data under investigation.
0.6 0.4 0.2 0.0 30-Nov-16
Exceptionally high Below normal
www.gov.uk/environment-agency
31-Jan-17
31-Mar-17
Notably high Notably low
31-May-17
31-Jul-17
30-Sep-17
30-Nov-17
Above normal Exceptionally low
Normal ─── Latest data
© Environment Agency 2017
Groundwater Levels Exceptionally high Below normal
Notably high Notably low
Above normal Exceptionally low
Normal ─── Latest data
CHILTERNS WEST - STONOR PARK - CHALK Ranking derived from data for the period May-1961 to Dec-2012
87 106 82
Level (mAOD)
Level (mAOD)
104 102 100 98
72 67
96
94 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
62 Dec-15 Mar-16 Jun-16
Sep-17
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
MARLBOROUGH DOWNS - ROCKLEY - CHALK
NORTH DOWNS - TILE BARN FARM - CHALK
Ranking derived from data for the period Mar-1933 to Dec-2012
Ranking derived from data for the period Oct-1971 to Dec-2012
144
93
142
92
140
91
Level (mAOD)
Level (mAOD)
77
138 136 134
90 89 88
132
87
130
86
128 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
85 Dec-15 Mar-16 Jun-16
Sep-17
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
CHILTERNS EAST - ASHLEY GREEN - CHALK
LEE CHALK WEST - LILLEY BOTTOM - CHALK
Ranking derived from data for the period Sep-1987 to Dec-2012
Ranking derived from data for the period Jul-1979 to Dec-2012
99
129
Level (mAOD)
Level (mAOD)
98 124
119
114
97 96 95
94 93
109 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
92 Dec-15 Mar-16 Jun-16
Sep-17
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
HAMPSHIRE DOWNS - CLANVILLE LODGE - CHALK
HAMPSHIRE DOWNS - LOPCOMBE CORNER - CHALK
Ranking derived from data for the period Mar-1963 to Dec-2012
Ranking derived from data for the period Apr-1963 to Dec-2012
95 90
93 91
86
Level (mAOD)
Level (mAOD)
88
84 82 80
89 87 85 83
78
81
76
79
74 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
www.gov.uk/environment-agency
Sep-17
77 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
© Environment Agency 2017
Groundwater Levels Notably high Notably low
Above normal Exceptionally low
ISLE OF WIGHT - CARISBROOKE CASTLE - CHALK
SOUTH DOWNS - WEST MEON - CHALK Ranking derived from data for the period Sep-1986 to Dec-2012
32
94
31
92
30
90
29 28 27
88 86 84 82
26
80
25
78
24 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
76 Dec-15 Mar-16 Jun-16
Sep-17
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
SOUTH DOWNS - HOUNDEAN BOTTOM - CHALK
NORTH DOWNS - CHIPSTEAD - CHALK
Ranking derived from data for the period Jan-1977 to Dec-2012
Ranking derived from data for the period Oct-1942 to Dec-2012
24
101 99
Level (mAOD)
19
Level (mAOD)
Normal ─── Latest data
Ranking derived from data for the period Aug-1977 to Dec-2012
Level (mAOD)
Level (mAOD)
Exceptionally high Below normal
14 9
97 95 93 91 89
4
87 Sep-16 Dec-16 Mar-17 Jun-17
85 Dec-15 Mar-16 Jun-16
Sep-17
Sep-17
NORTH DOWNS - SWEEPS LANE - CHALK
NORTH DOWNS - RIDDLES LANE - CHALK Ranking derived from data for the period Apr-1982 to Dec-2012
46
25
46
23
45 45 44 44
21 19 17
15 13
43 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
11 Dec-15 Mar-16 Jun-16
Sep-17
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
NORTH DOWNS - LITTLE BUCKET - CHALK
CHILGROVE HOUSE GWL
Ranking derived from data for the period Jan-1971 to Dec-2012
Ranking derived from data for the period Feb-1836 to Dec-2012
87
75 70
Level (mAOD)
82
Level (mAOD)
Sep-16 Dec-16 Mar-17 Jun-17
Ranking derived from data for the period Jan-1984 to Dec-2012
Level (mAOD)
Level (mAOD)
-1 Dec-15 Mar-16 Jun-16
77 72 67
65
60 55 50 45
62
57 Dec-15 Mar-16 Jun-16
40
Sep-16 Dec-16 Mar-17 Jun-17
www.gov.uk/environment-agency
Sep-17
35 Dec-15 Mar-16 Jun-16
Sep-16 Dec-16 Mar-17 Jun-17
Sep-17
© Environment Agency 2017
Reservoir Stocks 2003
LTA
MIN
2013
2016
2017
2003
Thames Water - Lower Thames Reservoirs - Lower Thames
LTA
MIN
2013
2016
2017
Thames Water - Lee Valley Reservoirs - Lower Lee
100
Percentage of live capacity
Percentage of live capacity
100 80
60
40
20
0
80
60
40
20
0 Jan Feb Mar Apr May Jun 2003
LTA
Jul
Aug Sep Oct Nov Dec
MIN
2013
2016
Jan Feb Mar Apr May Jun
2017
LTA
Thames Water - Farmoor Reservoir - Upper Thames
Percentage of live capacity
Percentage of live capacity
2013
2016
2017
100
80
60
40
20
0
80
60
40
20
0 Jan Feb Mar Apr May Jun LTA
MIN
Jul
Aug Sep Oct Nov Dec
2013
2016
Jan Feb Mar Apr May Jun
2017
LTA
South East Water - Ardingly Reservoir - Ouse
MIN
Jul
Aug Sep Oct Nov Dec
2013
2016
2017
South East Water - Arlington Reservoir - Cuckmere 100
Percentage of live capacity
100
Percentage of live capacity
Aug Sep Oct Nov Dec
Sutton & East Surrey Water - Bough Beech Reservoir Medway
100
80
60
40
20
0
80
60
40
20
0 Jan Feb Mar Apr May Jun LTA
MIN
Jul
Aug Sep Oct Nov Dec
2013
2016
Jan Feb Mar Apr May Jun LTA
2017
MIN
Jul
Aug Sep Oct Nov Dec
2013
2016
2017
Southern Water - Darwell Reservoir - Rother (Eastern)
Southern Water - Bewl Reservoir - Teise (Medway) 100
100 90
Percentage of live capacity
Percentage of live capacity
MIN
Jul
80 70 60
50 40 30 20
90 80 70 60 50 40 30 20 10
10 0
0 Jan Feb Mar Apr May Jun
www.gov.uk/environment-agency
Jul
Aug Sep Oct Nov Dec
Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
© Environment Agency 2017
Reservoir Stocks LTA
MIN
2013
2016
2017
LTA
Southern Water - Powdermill Reservoir - Brede
2013
2016
2017
100
Percentage of live capacity
100
Percentage of live capacity
MIN
Southern Water - Weir Wood Reservoir - Medway
80
60
40
20
80
60
40
20
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
Cumulative Rainfall Plots CUMULATIVE RAINFALL FOR HERTS AND NORTH LONDON AREA COMPARED WITH LONG TERM AVERAGE 2000
1500
1500
1000
Sep-17 Sep-17
Jul-17
Aug-17
Jun-17
Apr-17
May-17
Mar-17
Jan-17
Feb-17
Dec-16
Oct-16
Nov-16
Sep-16
Jul-16
Aug-16
Jun-16
Apr-16
May-16
Aug-17
CUMULATIVE RAINFALL FOR SOLENT AND SOUTH DOWNS AREA COMPARED WITH LONG TERM AVERAGE
Mar-16
Oct-15
Sep-17
Jul-17
Aug-17
Jun-17
Apr-17
May-17
Mar-17
Jan-17
Feb-17
Dec-16
Oct-16
Nov-16
Sep-16
Jul-16
Aug-16
Jun-16
Apr-16
May-16
Mar-16
Jan-16
0
Feb-16
0 Oct-15
500
Jan-16
Average
500
Feb-16
Average
1000
Dec-15
MILLIMETRES
2000
Dec-15
MILLIMETRES
CUMULATIVE RAINFALL FOR THAMES AREA COMPARED WITH LONG TERM AVERAGE
CUMULATIVE RAINFALL FOR KENT AND SOUTH LONDON AREA COMPARED WITH LONG TERM AVERAGE
2000
2000
1800 1500
1400
MILLIMETRES
MILLIMETRES
1600
1200
Average
1000 800
600
Average 1000
500
400 200
www.gov.uk/environment-agency
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-16
Aug-16
Jul-16
Jun-16
May-16
Apr-16
Mar-16
Jan-16
Feb-16
Oct-15
Dec-15
Sep-17
Aug-17
Jul-17
Jun-17
May-17
Apr-17
Mar-17
Feb-17
Jan-17
Dec-16
Nov-16
Oct-16
Sep-16
Aug-16
Jul-16
Jun-16
May-16
Apr-16
Mar-16
Jan-16
Feb-16
Oct-15
0 Dec-15
0
© Environment Agency 2017
www.gov.uk/environment-agency
© Environment Agency 2017
South East Areal Rainfall units for reference
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, 2017.
www.gov.uk/environment-agency
© Environment Agency 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 (m 3s-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 Notably high Above normal Normal Below normal Notably low Exceptionally low
Value likely to fall within this band 5% of the time Value likely to fall within this band 8% of the time Value likely to fall within this band 15% of the time Value likely to fall within this band 44% of the time Value likely to fall within this band 15% of the time Value likely to fall within this band 8% of the time Value likely to fall within this band 5% of the time
Cat code LIT 9025
www.gov.uk/environment-agency
© Environment Agency 2017
