Monthly Water Situation Report Lincolnshire and Northamptonshire Area

Monthly water situation report Lincolnshire and Northamptonshire Area

Summary – August 2021 After near average rainfall in July, August was drier than average. This saw the soil moisture deficit increase and flows in rivers decrease. The wet winter means that groundwater levels are normal or above normal and this has supported the baseflows in the groundwater fed rivers but some of the runoff dominated rivers are now classified as below normal

Rainfall Lincolnshire and Northamptonshire Area received an average of 26.1mm during August, 44% of the long term average. The lowest rainfall was in the Witham to Chapel Hill hydrological area with 22.5mm, 37% of the long term average and the highest was in the Louth Grimsby and Ancholme hydrological area with 31.6mm, 52% of the long term average.

Soil Moisture Deficit/Recharge In response to the dry August soil moisture deficits are either normal or above normal for the time of year.

River Flows River flows have been falling during August particularly in the runoff dominated river Welland and Nene catch- ments. Flows at 8 out of the 10 sites monitored are classified as normal for August with Brampton branch of the River Nene at St Andrews Mill and the Ashley on the River Welland classified as below normal.

Groundwater Levels Groundwater levels fell in line with the seasonal trend during August but because of the wetter than average winter recharge period these are classified as either normal or above normal for the time of year

Reservoir Storage/Water Resource Zone Stocks All reservoirs are near or above their normal operating curves.

Environmental Impact There have been 2 additional cessation notice issued for the River Bain during August. The River Witham to River Ancholme Transfer has been operating during August and the River Slea augmentation was turned on at the end of August. No fluvial Flood Alerts or Flood Warning were issued during August.

Forward Look Probabilistic ensemble projections for river flows at key sites September 2021: There is a reduced likelihood of exceptionally low flows this September in the River Nene. December 2021: There is an increased probability of flows below the normal range this December. Probabilistic ensemble projections for groundwater levels in key aquifers September 2021: Groundwater levels are project to be in the normal range in both the chalk and oolitic limestone aquifers this September. March 2022: There is reduced probability of groundwater levels being lower than below normal next March.

Author: Hydrology and Operations Contact details: 03708 506506

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 2021

Rainfall August 2021

P a g e | 2

Total Rainfall in Millimetres Long Term Average Rainfall in Millimetres 1-Month Period for Louth Grimsby and Ancholme 1-Month Period for Steeping Great Eau and Long Eau

100 120

90 100 80

70 80 60

50 60

40 40 30

20 20 10

0 0

Oct-20 Jul-21 Oct-20 Jul-21 Sep- Nov- Dec- Jan- Feb- Mar- Apr-21 May- Jun- Aug- Sep- Nov- Dec- Jan- Feb- Mar- Apr-21 May- Jun- Aug-

21 21 21 21

21 21 20 20 20 20 20 20

21 21

1-Month Period for Witham to Chapel Hill 1-Month Period for South Forty Foot and Hobhole

120 120

100 100

80 80

60 60

40 40

20 20

0 0

Oct-20 Jul-21 Oct-20 Jul-21 Sep- Nov- Dec- Jan- Feb- Mar- Apr-21 May- Jun- Aug- Sep- Nov- Dec- Jan- Feb- Mar- Apr-21 May- Jun- Aug-

21 21 21 21

21 21 20 20 20 20 20 20

21 21

1-Month Period for Upper Welland and Nene 1-Month Period for Lower Welland and Nene

140 140

120 120

100 100

80 80

60 60

40 40

20 20

0 0

Oct-20 Jul-21 Oct-20 Jul-21 Sep- Nov- Dec- Jan- Feb- Mar- Apr-21 May- Jun- Aug- Sep- Nov- Dec- Jan- Feb- Mar- Apr-21 May- Jun- Aug-

21 21 21 21

21 21 20 20 20 20 20 20

21 21

P a g e | 3

Soil Moisture Deficit

Ancholme Grimsby Louth Steeping Great Eau and Long Eau Ranking derived from data for the period Jan-1961 to Dec- Ranking derived from data for the period Jan-1961 to Dec- 2012 2012 0 0

20 20

40 40 60 60 80

80 SMD(mm) SMD(mm) 100 100 120

120 140

140 160 Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Witham to Chapel Hill South Forty Foot and Hobhole Ranking derived from data for the period Jan-1961 to Dec- Ranking derived from data for the period Jan-1961 to Dec- 2012 2012 0 0

20 20 40 40 60

60 80

80 100

SMD(mm) SMD(mm) 120 100 140 120 160

140 180 Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Upper Welland and Nene Lower Welland and Nene Ranking derived from data for the period Jan-1961 to Dec- Ranking derived from data for the period Jan-1961 to Dec- 2012 2012 0 0

20 20

40 40 60 60 80

80 SMD(mm) SMD(mm) 100 100 120

120 140

140 160 Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

P a g e | 4

River Flow August 2021

P a g e | 5

Exceptionally high Notably high Above normal Normal - - - - Max Below normal Notably low Exceptionally low ─── Latest data - - - - Min Louth Weir, LUD Rase Bishopbridge, ANCHOLME Ranking derived from data for the period Jul-1968 to Dec-2017 Ranking derived from data for the period Jun-1967 to Dec-2012

2.0 2.5 1.8 1.6 2.0 1.4 1.2 1.5 1.0

0.8 1.0 Flow (cumecs)Flow Flow (cumecs)Flow 0.6 0.4 0.5 0.2 0.0 0.0 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21

Claypole, UPPER WITHAM Partney, LYMN & STEEPING Ranking derived from data for the period May-1959 to Dec-2017 Ranking derived from data for the period May-1962 to Dec-2012

3.0 10 2.5 8 2.0

6 1.5

1.0

Flow (cumecs)Flow (cumecs)Flow

2 0.5

0 0.0 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21

Fulsby and Fulsby Model combined, BAIN Langworth, BARLINGS EAU Ranking derived from data for the period Oct-1962 to Dec-2012 Ranking derived from data for the period Jul-1980 to Dec-2012

6.0 10 9 5.0 8 7 4.0 6 3.0 5 4

2.0 Flow (cumecs)Flow Flow (cumecs)Flow 3 2 1.0 1 0.0 0 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21

Ashley, WELLAND Kates Bridge plus King Street, GLEN Ranking derived from data for the period Oct-1970 to Dec-2012 Ranking derived from data for the period Jan-1991 to Dec-2012

9 8.0

8 7.0

7 6.0 6 5.0 5 4.0 4 3.0

Flow (cumecs)Flow (cumecs)Flow 2 2.0 1 1.0 0 0.0 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21

P a g e | 6

Exceptionally high Notably high Above normal Normal - - - - Max Below normal Notably low Exceptionally low ─── Latest data - - - - Min Upton Mill Total, NENE (KISLINGBURY BRANCH) St.Andrews total, NENE - BRAMPTON BRANCH Ranking derived from data for the period Jan-1970 to Dec-2017 Ranking derived from data for the period Jan-1970 to Dec-2012

8 7.0

7 6.0 6 5.0 5 4.0 4 3.0

3 Flow (cumecs)Flow Flow (cumecs)Flow 2.0 2

1 1.0

0 0.0 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21 Nov-20 Jan-21 Mar-21 May-21 Jul-21 Sep-21

P a g e | 7

Groundwater Levels August 2021

Exceptionally high Notably high Above normal Normal - - - - Max Below normal Notably low Exceptionally low ─── Latest data - - - - Min Dunholme Road, Scothern Castlethorpe Bridge Ranking derived from data for the period Nov-1979 to Dec-2017 Ranking derived from data for the period Nov-1996 to Dec-2017

23 3.0

22 2.5 21 2.0 20 19 1.5 18 1.0

17 0.5 Level (mAOD) Level Level (mAOD) Level 16 0.0 15 14 -0.5 13 -1.0 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21

P a g e | 8

Exceptionally high Notably high Above normal Normal - - - - Max Below normal Notably low Exceptionally low ─── Latest data - - - - Min Leasingham Exploratory - LINCS LIMESTONE Grange Farm, Aswarby - LINCS LIMESTONE Ranking derived from data for the period Sep-1972 to Dec-2017 Ranking derived from data for the period Dec-1970 to Dec-2017

22 23 20 21 19 18 17 16 15 14 13 12

Level (mAOD) Level (mAOD) Level 10 9 8 7 6 5 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21

Greatford Hanthorpe - LINCS LIMESTONE Ranking derived from data for the period Jul-1974 to Dec-2017 Ranking derived from data for the period Jul-1972 to Dec-2017

20 17 18 15 16 13 14 11 12 9 10 7 8

5 Level (mAOD) Level Level (mAOD) Level 6 3 4 1 2 -1 0 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21

Grainsby - LINCS CHALK Horkstow Road, Barton-upon-Humber Ranking derived from data for the period Oct-1977 to Dec-2017 NORTH LINCS CHALK Ranking derived from data for the period Apr-1980 to Dec-2017 24

22 9 20 18 7 16 14 5 12

3 Level (mAOD) Level Level (mAOD) Level 10

8 1 6 4 -1 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21 Nov-18 Mar-19 Jul-19 Nov-19 Mar-20 Jul-20 Nov-20 Mar-21 Jul-21

P a g e | 9

Reservoir Stocks August 2021

Rutland Pitsford 100 100

90 90

80 80

70 70

60 60

50 50

40 40

30 30 Percentage of live capacitiylive of Percentage Percentage of live capacitiylive of Percentage 20 20

10 10 1996-1997

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 Combined Ravensthorpe and Hollowell Covenham 100 100

90 90

80 80

70 70

60 60

50 50

40 40

30 30 Percentage of live capacitiylive of Percentage Percentage of live capacitiylive of Percentage 20 20

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

Normal Operating Curve ------Drought Curve ---- 1995-1996 - - - - 2020-21 ------

P a g e | 10

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 September 2021. 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) Geo- logical map reproduced with kind permission from UK Groundwater Forum, BGS © NERC. Crown copyright. All rights reserved. Environment Agency, 100026380, 2021. ^ “Naturalised” flows are projected for these sites’

P a g e | 11

Forward Look – River Flows

Probabilistic ensemble projections of river flows at key indicator sites in December 2021. 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) Geo- logical map reproduced with kind permission from UK Groundwater Forum, BGS © NERC. Crown copyright. All rights reserved. Environment Agency, 100026380, 2021 ^ “Naturalised” flows are projected for these sites’

P a g e | 12

Forward Look - Groundwater

Probabilistic ensemble projections of groundwater levels at key indicator sites for end of Sep- tember 2021. 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, 2021.

P a g e | 13

Forward Look - Groundwater

Probabilistic ensemble projections of groundwater levels at key indicator sites for end of March 2022. 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, 2021.

P a g e | 14

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 per- meability 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. Ex- pressed 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.

Groundwater Level The water level measured in an aquifer at a borehole, which includes the impacts of artificial influence.

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 param- eter 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 ser- vice 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.

River Flow The flow in the river measured at a gauging station, which includes the upstream impacts of artificial influence.

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).

P a g e | 15