Local flood risk management strategy

Transcription

Local flood risk
management strategy
www.portsmouth.gov.uk
2 • Local flood risk management strategy
Foreword
Portsmouth is a densely populated, urbanised
island city which has been shaped historically
by its relationship with the sea. This
relationship will also define our future. Many
areas within our conurbation are low lying and
protected from flooding by pumped drainage
systems and man-made flood defences.
Consequently, 12,500 residential properties
and over 1,000 commercial properties are
currently located in the tidal flood risk zone,
with up to another 1000 properties also at
risk from surface water flooding. Sea level
rise predictions forecast that in 2115 nearly
31,000 residential and 2,000 commercial
properties in Portsmouth will be at risk.
Working from guidance given in recent
government legislation (The Flood and Water
Management Act 2010) this strategy sets out
for the first time how Portsmouth City
Council works with the Environment Agency,
neighbouring local authorities, emergency
services and water companies to reduce all
forms of flood risk in the city.
Our flooding problems relate to coastal flood
risk, surface water and ground water. The
strategy sets out to explain these different types
of flooding and how we are working to reduce
the risk from them. This work will encourage
regeneration and bring inward investment to
the city as flood defences and drainage
networks are improved for the benefit of all.
Our strategy focuses on flood risk on a ward
by ward basis. It identifies known flooding
problems and how we are dealing with them
along with on-going issues where we are
working to find a solution. We are already
gaining momentum for refurbishment of the
sea defences at Southsea and North Portsea
Island and fully expect work for Phase 1 at
North Portsea to commence in Spring 2015.
Thank you for your interest in this subject
– so often taken for granted, but so
important to the future of our city.
Southern Water has also undertaken major
work in the city aimed at reducing flood risk to
properties from surface water, and we will
shortly be investigating levels of groundwater
around the city to determine whether or not
this will be an increasing problem in the future.
David Williams
Chief Executive
Portsmouth City Council
This is an exciting time for Portsmouth and
we cannot afford to be complacent. The
council will ensure the work we do takes into
account all the existing plans we have for
regeneration and improvement and we will
maximise any opportunity that allows us to
work with other organisations both public
and private, so we have a safe environment
to live and work in.
Whilst flooding can never be fully eliminated,
I believe this document, which
includes recent revisions relating to
the storms in 2014, sets out our
plans for the reduction of flood
risk and how we are working in
a co-ordinated approach with
our partners and stakeholders
to provide the greatest levels
of flood protection possible
for the city both now and in
the future.
Foreword • Local flood risk management strategy • 3
Contents
Introduction
6
Historic flooding in Portsmouth
9
Location
10
Flood risk in Portsmouth
12
Interactions between different types of flooding
21
Climate change
22
Citywide flood risk measures
4 • Local flood risk management strategy • Contents
24
Flood risk ward by ward
35
Protecting individual residential properties and flood insurance
64
Action plans
66
What you can do to minimise the effects of flooding
72
References
73
Glossary of terms
74
Contents • Local flood risk management strategy • 5
Introduction
Flooding is one of the biggest natural challenges facing Portsmouth.
Our position as a coastal city brings great benefits and these are
reflected in the council’s goal to shape the great waterfront city.
However, the risk of flooding from the sea, along with that from
surface water, are significant issues facing the city due to their
potential to threaten people, property and the environment. This risk
will increase as a result of climate change. Whilst we cannot entirely
eliminate the risk of flooding, this strategy aims to locally manage
flood risk for the people, economy and environment of Portsmouth.
Why has the strategy been written?
As a unitary authority, Portsmouth City Council is designated as a
Lead Local Flood Authority (LLFA) under the Flood and Water
Management Act 2010 (the ‘act’). The act places a statutory duty on
LLFA’s to develop, maintain, implement and monitor a Local Flood
Risk Management Strategy (hereafter referred to as the ‘strategy’) to
manage local flood risk in its area. The strategy aims to locally
manage flood risk for the people, economy and environment of
Portsmouth by working in partnership to identify and deliver feasible
and timely actions.
What are the guiding principles behind the strategy?
The strategy is focused on the following principles as set out in the
‘National Flood and Coastal Erosion Risk Management Strategy
(NFCERM)’ with which our local strategy must be consistent.
• Community focus and partnership working
• Catchment and coastal cell based approach
• Sustainability
• Proportionate, risk-based approaches
• Multiple benefits
• Beneficiaries should be allowed and encouraged to invest in local
flood risk management
6 • Local flood risk management strategy • Introduction
What is included in the strategy?
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The strategy must consider flood risk from surface water, ground
water and ordinary watercourses; however, we decided to include
coastal flood risk as a major consideration for Portsmouth. It can be
difficult to identify the type of flooding during an incident and often
it can be a combination of different types. By including all sources
of flood risk within this strategy, it provides a clear overview of flood
risk within Portsmouth and the co-ordinated approach to managing
these risks.
A27
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The document has already been revised to include actions resulting
from the storms of winter 2013/14.
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ROAD
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ROA
SQUA
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RO
ROAD
DARLINGTO
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WIMB
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ROAD
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CARISBROOKE ROAD
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ROAD
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TON
MIL
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BAT
ROAD
WHITWORTH
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INGLIS ROAD
ROAD
MI
FR
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ROAD
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STANS TED ROAD
LIVINGSTONE ROAD
RD
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ROAD
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ASHBY
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RO
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RICHMON
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LAND
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END
OA
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V
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CL
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RODN
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C
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ROAD
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GOLD ST
HAMBR
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ADAMES ROAD
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RE
PE
D
MOORLAND ROAD
NE
SHEARER ROAD
LA
DAULSTON ROAD
M
KING ST
STREET
BELM
ONT
CK
ON
GLENCOE ROAD
PEA
CO
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STR
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ROAD
M
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AD
RO
Baffins
R
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HAYLING AVENUE
EST
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AD
THORNCROFT ROAD
AVE
NUE
ROA
D
TA
KIRPAL ROAD
SELBOURNE TERRACE
CA
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IS
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AVENUE
BRAD
HU
ROAD
RD
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BROUG
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LANG
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RO
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MUS
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CR
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RO
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ROA
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ROA
D
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ROAD
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STR
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ARIEL ROAD
IA
NANCY ROAD
FR
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ROA
WINSTON CHURCHILL
STREET
GROSVENOR
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FRATTON ROA
STREET
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DS
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GUILDFORD ROAD
STRR
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T ROAD
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ROAD
ROAD
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BROOKFIELD ROAD
LIVER
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SHEFFIELD ROAD
SANDRINGHAM ROAD
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VIEW
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RT ST
LANDPO
WAY
RAIL
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BURNABY ROAD
D
ROA
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NR
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WAY ROAD
HANA
STREET
BURITON ST
TR
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GREETHAM STREET
ROAD
ALVER ROAD
STREET
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GARNIE T REET
ARU
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DP
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ST
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PAR
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COBUR
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NUE
TANGIER ROAD
T
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TR
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CLIVE ROAD
WIMPO
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EAST
BEECHAM ROAD
ST
ARUNDEL STREET
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UP
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STREET
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COR
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STREET
QUEEN STR EET
AL
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TW
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NORTH
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R RO
Charles Dickens
CUMBERLAND STREET
STRE
FOSTE
AD
RO
E
LAK
AD
E RO
LAK
D
EL
FI
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ON
M
TEIGNMOUTH ROAD
EASTBOUR NE ROAD
NEW ROAD
ROAD
URT
HAM P SHIRE STREET
MANOR ROAD
D
DON
CLAREN
RN W A L
Y
TWA
RKE
MA
NEW ROAD
D
GE
PLACE
NUTFIELD
T
KESWICK AVENUE
Fratton
HARCO
T
RE
ET
VON ROAD
CARNAR
ST
A
ROA
ES S
INVERN
DUKE
A
T URNER R O
ST
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CE
ES
CR
L IS
ROAD
CYPRUS
N
CH
UR
CH
ROAD
MALTA
NEW
CE
CO
ROAD
TO ROAD
TORON
ES
M
ET
RE
ST
BINSTEED
CR
AD
USE RO
FLATHO
STREET
SEYMOUR CLOSE
JERSEY ROAD
WINCHESTER ROAD
SULTA
N ROAD
PRINCE’S ST
VICTORIA
KENDAL AVEN
UE
LDS ROAD
E
NU
VE
EET
AN
EMM UEL ST
WALLINGTON ROAD
QUEEN’S ROAD
RD
WASHINGTON
B URRFIE
E
AV
D RI
5
PROSPEC
T ROAD
SEAFIELD ROAD
A
POWERSCOURT RO D
ROAD
CLYDEBANK
CLOSE
TON WAY
BIL
7
M2
N ESSUS STR
CHICHESTER ROAD
PORTCHESTER ROAD
E RD
ET
TRE
STIRLI NG S
KING WILLIAM STREET
MAYHALL ROAD
EPWORTH ROAD
The strategy will be treated as a ‘living’ document and will need to be
reviewed annually in line with other plans and strategies. The review
procedure will be undertaken at Portsmouth City Council’s Flood Risk
Strategy Group meetings. If there is a flood event with significant
consequences, an ad-hoc review of the strategy may be prompted.
The lifetime of the strategy is up to 2018, at which time there will be
a major review. The short life-span is due to major investment in
coastal defences and drainage over the next five year period.
BURRFIELDS ROAD
TOKIO ROAD
COPYTHORN ROAD
LABURNUM GROVE
WYMERING ROAD
MALTHOUS
WINTON ROAD
ROAD
OAD
How and when will the strategy be reviewed?
DUNDAS SPUR
GLENTHORNE ROAD
LONDON ROA
D
SEAGROVE R
BEV IS ROAD
KINGSTON CRESCE
NT
D
WYKEHAM ROAD
STANLEY ROAD
ROAD
FIELD
GAR
Copnor
MONC KTON ROAD
AD
HEATHCOTE RO
STUBBINGTON AVENUE
PITCROFT ROAD
LOCARNO ROAD
VERNON ROAD
STAMSHAW ROAD
MONTAGUE ROAD
E
MONMOUTH ROAD
TWYFORD AVENUE
CARDIFF ROAD
RD
R OAD
ALLCOT ROAD
DOMUM ROAD
DARTMOUTH
S AVENU
GLADY
CONNAUGHT
ANGERSTEIN ROAD
DERBY
AD
RO
OVE
D
MEYRICK ROAD
KNOX ROAD
E
E
END GR
NORTH
GLADYS AVENUE
NELSON AVENUE
Y ROA
WIDLE
WINSTANLEY ROAD
IC
RV
SE
AD
RO
ROAD
5
M27
Nelson
KIRBY ROAD
LA N
Y
L WA
INE
MA
T ER
AR
QU
TARGET
THURBERN ROAD
LOWER DERBY R
OAD
O
MAYFIELD ROAD
MUNSTER ROAD
WHALE ISLAND WAY
UE
ST SWITHUN’S ROAD
HEWET T ROAD
INHURST ROAD
OT
LC
HO
IV
E
O N L A NE
T
OR
RP
NE
ST C H A D ’S AVENUE
ROAD
N AVENUE
LONDO
WILSON ROAD
NEWCOMEN ROAD
GATCOMBE AVEN
NUE
ROAD
ORIEL ROAD
WADHAM
TH END
NOR
AVENUE
EC
T
D
AI
R LA
ROAD
ROAD
N ROAD
GRUNEISE
E
OP
LOVETT ROAD
GREEN LANE
BATTENBU
RG AVE
JERVIS
STRODE
HEL
ROA
WESLEY GROVE
COMPTON ROAD
OPHIR ROAD
ROAD
WALDEN
SQUARE
ROAD
ROAD
ROAD
SHADWELL
AD
R RO
TIPNE
UR WAY
HARBO
CHILDE
MITC
ROAD
WINDERMERE RO
AD
TIPNE
MADEIRA
OSIER C LOSE
WIL
LIA
AMBERLEY ROAD
MERRIVALE
TORRINGTON
DR
SYW
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HOR
AGE
NEVILLE SHUTE
ROAD
H ROA
D
ROAD
MAGDALEN
HARTLEY
COPNOR ROAD
MERE
DIT
ROAD
KIPLING
CRESCENT
LL
ANC
MS
DRIVE
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SYW
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R
CO
RO
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RO
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EN
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ROAD
NOR
WAY
ROA
D
MER L
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GATCOMBE
E RI DING
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ON
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POR
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RO
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CURTI
AVENUE
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DOYLE
DR
OA
D
ROAD
HO RP
HERN
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D
WOO
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AD
WOOD
H ROAD
ALT
BEECHW
WAY
ROAD
SOUTH
NORT
R OA D
WOO
Hilsea
ELM
WYLIE
E
IN
ROAD
EA
HORS
AD
ND
RO
ROAD
AN D Y
LO
CLOS
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CLOS
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A
WAR
SPITE
PAN
ORT
RO
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ROAD
OAK
RD
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NOR M
R
PE
NORT
W
SPIN
NAK
E
HO
R DRIVE
HANOVER ST
© Crown Copyright and database right 2013. Ordnance Survey licence number 100019671.
E
The strategy is also intended to identify projects to reduce flood risk
and identify who, how, where and when the projects will take place.
This includes referencing projects recently completed, underway or
already programmed by the risk management authorities.
T RO
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HILSE
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FAWL
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AD
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A27
SC
OT
HORSE
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FIRGROVE
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MILITAR
SOUT
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Introduction • Local flood risk management strategy • 7
What are the strategy objectives?
The strategy objectives set out below were agreed by the strategy working group, which included representatives from PCC Drainage, Planning
and Coastal teams, the Environment Agency and Southern Water.
1. We seek to improve the knowledge and understanding of all
sources of flood risk across Portsmouth, to include (in no
particular order of importance):
Surface water and run-off
Groundwater
Ordinary watercourses
Fluvial (main rivers)
Coastal
Reservoir
Sewer overload
Mains water supply bursts
2. Identify and work in partnership with other authorities,
stakeholders and the community who have a role in flood risk
management.
3. Increase public awareness of all flood risk across Portsmouth.
8 • Local flood risk management strategy • Introduction
4. Ensure that planning decisions are properly informed by flooding
issues, by avoiding development at inappropriate locations and
reducing flood risk wherever possible.
5. Maintain, and improve where necessary and affordable, flood risk
management infrastructure and systems to reduce flood risk.
6. Identify through an action plan, appropriate measures, and
schemes to manage flood risks providing balanced community
and environmental benefits, and establish who is responsible for
delivery of these measures.
7. Compile a funding plan for schemes listed on the action plan
8. For identified schemes, demonstrate compliance with the EU
Water Framework Directive through a Strategic Environmental
Assessment and Habitats Regulations Assessment.
9. Detail all procedures in place to mitigate a flood event, including
flood response and recovery
Historic flooding in Portsmouth
© City Development and Cultural Services, Portsmouth City Council
Southsea Common after ‘The Great Gale’, 1910
Broad Street, Old Portsmouth circa 1900-1920
Broad Street, Old Portsmouth 1989
Clarendon Road, Southsea, 2000
Historic flooding in Portsmouth • Local flood risk management strategy • 9
Location
© Crown Copyright and database right 2013.
Ordnance Survey licence number 100019671.
Portsmouth is bordered by four district boroughs, all within Hampshire County Council, which is the designated LLFA for each of these areas.
However, as explained later in the strategy, Portsmouth has only minor flood risk interaction with our neighbouring authorities. Comments from
the drainage departments in the adjacent authorities are shown overleaf. They describe from a localised perspective, any flooding which may be
common with Portsmouth and its neighbours.
10 • Local flood risk management strategy • Location
Interactions with surrounding boroughs
i. Havant Borough Council:
Havant has a partial land boundary with Portsmouth, but the
southern part of the boundary (Hayling Island) interacts with
Langstone Harbour by means of surface water, treated waste
water and occasionally in times of extreme weather events,
partially treated dilute wastewater which is discharged via
consented storm overflows.
Southern Water have confirmed that there is very little surface or
foul water interaction between Fareham and Portsmouth as the
western boundary of Budds Farm’s drainage catchment follows
Portsmouth City Council’s western administrative boundary.
Reach 1 of the Portchester Castle to Emsworth Coastal Strategy
extends into Fareham Borough Council catchment by 3670m
(PCC = 1945m)
Anecdotal evidence indicates that: The Westways estate [Havant
Road] drains (foul and storm water) into Portsmouth systems – the
storm water goes to the PCC/HBC boundary ditch which drains
south under the railway and the A27 into Farlington Marshes. The
private drainage from Farlington Redoubt (in HBC’s area) comes
into PCC catchment down the access road, and probably so does
Fort Purbrook foul water, assuming that’s not on cess pools. Fort
Purbrook storm drainage travels north away from PCC.
iv. Gosport Borough Council:
Reach 3 of the Portchester Castle to Emsworth Coastal Strategy
extends into Havant Borough Council catchment by 880m
(PCC = 8180m)
Portsmouth has very limited interaction with other boroughs in terms
of surface and groundwater. This is due to the topography, geology
and the manner in which the drainage system works. Both
Portsmouth and Langstone Harbours are tidal and are influenced by
the River Walllington and Hermitage Stream respectively. Due to the
size of both harbours, the impact of flows from the rivers are minimal
and any pollution would be quickly diluted and its effect minimised.
Bedhampton Springs, which are the source of Portsmouth’s water
supply, are within Havant Borough Council catchment.
ii. Winchester City Council:
Anecdotal evidence indicates that: The River Wallington flows
behind Portsdown Hill and into Portsmouth Harbour at
Wallington, so this may have an impact on the flow in the harbour
but it would be minimal given the harbour’s size.
There is no drainage interaction between the catchments as
Gosport does not have a land boundary with Portsmouth. Both
authorities interact with Portsmouth Harbour by means of surface
water, treated waste water and occasionally in times of extreme
weather events untreated waste water.
Summary:
The Portchester Castle to Emsworth Coastal Strategy includes
interactions with Fareham and Havant Borough Councils. The Eastern
Solent Coastal Partnership working on behalf of the council covers all
three areas, allowing the actions for the cells to be addressed across
council boundaries.
iii. Fareham Borough Council:
Location • Local flood risk management strategy • 11
Flood risk in Portsmouth
Surface water
Surface water flooding or surface run-off, is also known as pluvial
flooding. This type of flooding occurs when rainfall cannot soak
into the ground and then overwhelms the local drains and flows
across the surrounding area. This type of flooding is often (but not
exclusively) associated with high intensity rainfall and occurs very
quickly during or after the rainfall event.
Surface run-off refers to the overland flow of surface water until it
reaches a point where it can enter a watercourse or sewer. These
flows can be significant depending on their depth, direction and
velocity and are represented in Flood Hazard mapping.
Surface water flooding is often quite localised and is much more
difficult to predict than river or coastal flooding. There is often limited
advance notice of this type of flooding and it generally occurs after
prolonged heavy rainfall or high intensity thunderstorm events.
Typical surface water flood incidents in Portsmouth
12 • Local flood risk management strategy • Flood risk in Portsmouth
Surface water flood risk map
An extract from the Environment Agency’s ‘Areas Susceptible to
Surface Water Flooding’ (AStSWF) map was used to help determine
areas of surface water flood risk for Portsmouth’s Surface Water
Management Plan. The map was produced on a national scale using
set parameters, and was considered more accurate by the Surface
Water Management Plan stakeholders than the ‘Flood Map for
Surface Water’ (FMfSW), which was produced as a follow up to the
above. There appeared to be more correlation with known flooding
issues in Portsmouth with AStSWF.
A further map, the ‘Updated Flood Map for Surface Water’ (uFMfSW),
is being produced by the Environment Agency which takes into
consideration local level information and modelling. This is was
published in December 2013.
These maps are frequently used by the insurance industry to identify
properties at risk of surface water flooding.
A road gully not functioning
Flood risk in Portsmouth • Local flood risk management strategy • 13
Coastal flooding
Flooding from the sea (coastal flooding) tends to occur as a result
of high tides, surges in sea water and strong winds which raise the
sea level above the ground level of the coast or the level of any
infrastructure present e.g. flood defences. Coastal flooding can also
occur as a result of failure of infrastructure.
Coastal flooding is generally well understood, can be predicted to
some extent, and flood protection measures are in place at many
locations at risk from this type of flooding.
The Eastern Solent Coastal Partnership currently manages
improvements to and maintenance of the majority of the city’s sea
defences on behalf of Portsmouth City Council. However, some
defences are owned and maintained by third parties e.g. MoD
maintain the defences around HM Naval Base.
The main coastal flood risk occurs during a high tide event in stormy
conditions with tidal surge and either a south westerley or south
easterley storm.
Tidal flood overtopping on the ‘wet’ side of the flood gates at Old Portsmouth.
Wave overtopping
Southsea seafront is exposed to the open Solent water where wave
action can be heavily influenced by weather conditions and shipping
movements. This can give rise to flooding by overtopping of the sea
defences, leading to floodwater inundation behind the defences.
Two sections of Southsea frontage are often closed to vehicular
traffic by road gates during, or in anticipation of such events, as wave
overtopping can spray shingle onto the road, making it unsafe to pass.
NOTE: tide heights are measured in Chart Datum (mCD) around
Portsmouth, which can be calculated by adding 2.73m to the Above
Ordnance Datum (mAOD) level.
Shingle on promenade at Southsea following a storm event
Coastal squeeze
Coastal squeeze is the term used to describe what happens to coastal
habitats that are trapped between a fixed landward boundary, such
as a sea wall, and rising sea levels and/or increased storminess.
The habitat is effectively ‘squeezed’ between the two forces and
diminishes in quantity and or quality. In the Solent it is the saltmarshes
that are perhaps under the greatest threat from this effect. Coastal
habitats will naturally adapt to a changing climate by migrating inland
but, in highly populated areas like the Solent, there is no room for
this process to happen as the land is used for industry, housing or
recreation, and will be defended due to its high commercial value.1
Natural habitat migration
Saltmarsh erodes at
the seaward edge
Saltmarsh ‘migrates’
landwards
Defences in Old Portsmouth to prevent coastal erosion
Mean sea level
Sea level rise and
increased
storminess
Coastal erosion
Intertidal zone
Coastal squeeze
Area ‘squeezed as
saltmarsh erodes at
the seaward edge
Mean sea level
Sea level rise and
increased
storminess
Intertidal zone
Sea
wall
Saltmarsh
cannot migrate
landwards due
to presence of
sea wall
Coastal erosion is the wearing away of land and the removal of beach
or dune sediments by wave action, tidal currents, wave currents, or
drainage. Waves, generated by storms, wind, or fast moving motor craft,
cause coastal erosion, which may take the form of long-term losses of
sediment and rocks, or merely the temporary redistribution of coastal
sediments. Erosion in one location may result in an accumulation of the
eroded sediment nearby.
Portsmouth’s southern frontage experiences a natural process called
‘longshore drift’, meaning the sediment and shingle on Southsea
beach is redistributed over time along the coastline by tidal currents
and storms. This effect is regularly monitored to ensure the extent
of the erosion is not detrimental. The sediment is redistributed by
machinery as necessary.
Coastal flood risk map
EA flood zone 3 (1/200) 0.5% AEP
This map shows Environment Agency Flood Zone 3, which has been
produced on a national scale. The hatched area shows the areas that
could be affected by flooding, either from rivers or the sea, if there
were no flood defences. These areas could be flooded from the sea
by a flood that has a 0.5 per cent (1 in 200) or greater chance of
happening each year.2
The probability or likelihood of flooding is described as the chance
that a location will flood in any one year. If a location has a 0.5%
chance of flooding each year, this can also be expressed as having:
• a 1 in 200 chance of flooding in that location in any year
• odds of 199 to 1 against a location being flooded in any year
However, this does not mean that if a location floods one year, it will
definitely not flood for the next 199 years. Nor, if it has not flooded
for 199 years, will it necessarily flood this year.3
The coastal flood response team (Colas and ESCP) monitoring a high tide in Old Portsmouth
Groundwater
Groundwater may be present within permeable geological formations
(aquifers) and permeable worked or filled ground (sometimes referred
to as made ground). Under certain conditions the groundwater table
can rise significantly above its normal level and cause flooding of
property and structures both above and below the ground surface.
When this happens due to natural processes (rather than a leaking
water main for instance) it is known as groundwater flooding.
Groundwater flooding is usually preceded by long periods of heavy
rainfall but does not occur rapidly in the same way as fluvial flooding,
so the potential hazards to life and health are not as immediate or
severe. However, once groundwater flooding has begun, it often
takes a long time to recede, and may result in significant property
damage and disruption.
A recent groundwater flood event in Portsmouth
Local rise in water table due to
low permeability obstruction
Groundwater emergence
Water table
Ground level
Water table
Non-aquifier
Groundwater flow
Aquifier
Groundwater flood risk map
The map here is a combination of
information used to determine groundwater
areas for investigation. The Environment
Agency ‘Areas Susceptible to Groundwater
Flooding’ map was considered too short of
detail for Portsmouth, as it was determined
on 2km square grids.
Figure 20 Target Areas and Regions for groundwater flood risk management
Target Areas for Groundwater
Flood Risk Management
Target Regions
Target Areas
Surface Water LFRZs
Strategic Development Sites
Portsmouth Plan
SHLAA
151
44
10
11
• Influence detailed design of coastal projects
48
39
03
02
164
04
8
05
6
146
06
Tipner
07
09
10
5
08
9
6
4
Somerstown and North Southsea
1
11
168
152
3
City Centre
29
172
13
12
178
• potential sewer infiltration rates
• Influence on flood risk, and
165
101
25 new borehole sites have been selected
by PCC Drainage Team in conjunction with
Southern Water, Eastern Solent Coastal
Partnership and PCC Planning. Along with a
network of existing boreholes, groundwater
levels will be monitored to ascertain a trend
for groundwater across the city. This will be
used to inform:
• Suitability of SuDS for new developments
159
7
These areas will be targeted by Portsmouth
City Council to determine current and future
levels of risk through data monitoring.
• Relationship to rain and tide events,
01
76
47
This map includes the latest strategic
development planning information like the
‘Strategic Housing Land Availability Assessment’
(SHLAA) and Surface Water Management
Plan Local Flood Risk Zones (LFRZs).
• Ground contamination levels (at time of
borehole installation)
161
2
127
85
10
2
49
14
143
176
163
0
Kilometers
0.25
±
0.5
1
Reproduced from Ordnance Survey material with the permission of Ordnance Survey on behalf of
Her Majesty's Stationery Office. © Crown Copyright. Portsmouth City Council, 2013 100019671.
Sewer surcharge
Sometimes referred to as hydraulic overload or foul flooding, flooding
from sewers often occurs at the same time as other types of flooding
(particularly surface water flooding) and can be a result of blocked
drains or the sewer network being unable to hold all the water
flowing into it. It can be identified by water escaping from a manhole.
This type of flooding is the responsibility of the pipework owner,
normally the local sewerage company. Portsmouth City Council
maintains good working relationships with Southern Water and assist
them in the investigation of any flooding from sewers.
A sewer manhole surcharging in Portsmouth
Fluvial flood risk (rivers)
Fluvial flooding is also known as river flooding. It occurs when a
river cannot hold the volume of water which drains into it from the
surrounding land (known as a catchment) as water is not able to
be conveyed within the channel and overflows onto the adjacent
floodplain. In the context of this strategy, we refer to fluvial flooding
as flooding from main rivers. A ‘main river’ is defined in the Water
Resources Act 1991 as ‘a watercourse shown as such on a main
river map and includes any structure or appliance for controlling
or regulating the flow of water into, in or out of the channel’.
Portsmouth has two designated main rivers (Great Salterns Drain and
Farlington Marshes Gutter), but neither effect properties during a
flood event as they are in floodplains which have no development.
Great Salterns Drain, an EA designated main river
Ordinary watercourses
Aftermath of a burst water main. Debris, water and sunken
footpaths are visible
An ‘Ordinary watercourse’ is defined in the
act as ‘a watercourse that does not form part
of a main river’. This includes lakes, ponds
or other areas of water that flow into an
ordinary watercourse. Portsmouth has a small
number of ordinary watercourses, which do
not pose a flood risk to properties.
Reservoirs
The Reservoir Act 1975 states ‘a reservoir is
a ‘raised reservoir’ if it is designed to hold, or
capable of holding, water above the natural
level of any part of the land adjoining the
reservoir’.
Portsmouth Water operates one underground
reservoir within Portsmouth’s catchment
which according to the act does not require
consideration as a flood risk as it is below ground.
Water mains
The act also states that ‘a flood caused by a
burst water main’ is not required for flood
risk consideration. This is because burst water
mains are almost impossible to predict and
generally occur randomly, most likely as a
result of infrastructure failure.
Reservoir and burst water main flooding are
not investigated in Portsmouth’s strategy.
Main river and ordinary watercourse
flooding is also considered low risk and are
not actively investigated in the strategy.
A new watercourse on Great Salterns Golf Course
Interactions between different types of flooding
The interaction between different water sources can have an impact on flooding. These are explained below:
Surface water and tide
Surface water flooding is also exacerbated at locations where seepage
occurs beneath the defences, which contributes to maintaining a
high water table. The ground geology indicates that this may be the
case on the southern part of Portsea Island, which would result in
high groundwater levels at Southsea. ‘Tidelocking’ can also occur,
when a gravity flow surface water network cannot discharge to the
sea during a high tide. This causes surface water to back up and
increasing flood risk. Tidelocking is exacerbated by sea levels if sea
water is not prevented entering the sewer through the outfall e.g.
dysfunctional flap valve.
Surface water and sewer surcharge
Large parts of Portsea Island are served by combined sewers. This
means surface water uses the same trunk sewers as foul water, during
a rain event diluted foul water may be surcharged from a combined
sewer manhole. This poses a health and safety concern and often
results in a lengthy and costly clean up operation.
Groundwater and sewer surcharge
Many of Portsmouth’s sewers are of Victorian brick construction and
are liable to groundwater ingress, especially those at significant depth
from the surface. If the pipe joints are not properly sealed, ground
water enters the sewer network reducing its capacity and increasing
flood risk. It is difficult to quantify the amount of groundwater in
the sewers. Southern water have recently completed sewer lining in
Old Portsmouth to prevent seawater infiltration to the sewers
Groundwater and tide
Tidal levels are often mirrored in groundwater levels. High tides
can mean high groundwater levels especially in proximity to the
coast. This can be difficult to quantify as considerations such as the
permeability of the sub-soil and the condition of sea defences are
recognised as having an influence. Generally there is a slight time
delay between peak tide level and peak groundwater level.
Old Portsmouth Tide and Ground Water Level (GWL) comparison
25 November 2009 to 30 November 2009
5.00
4.50
4.00
Water Level (m)
Surface water and groundwater
Differentiating between groundwater flooding and surface water
which cannot infiltrate can be difficult. Groundwater flooding need
not occur after a local rainfall event; rainfall falling further away
may cause groundwater levels to rise over a much wider area, e.g.
due to an extensive aquifer, and thus cause groundwater flooding
at other locations. Again, if the ground is already saturated and
causing groundwater flooding, then any further local rainfall will
be unable to infiltrate and result in surface water flooding. PCC has
experienced a groundwater flood incident (95% certainty) in Baffins
ward in early 2013.
3.50
Recorded Borehole
GWL (mCD)
3.00
Sea Level (mCD)
2.50
2.00
1.50
17:00
22:00
03:00
08:00
13:00
18:00
23:00
04:00
09:00
14:00
19:00
00:00
05:00
10:00
15:00
20:00
01:00
06:00
11:00
16:00
21:00
02:00
07:00
12:00
17:00
22:00
03:00
08:00
13:00
18:00
23:00
04:00
1.00
Time
Interactions between different types of flooding • Local flood risk management strategy • 21
Climate change
Evidence:
There is clear scientific evidence that global climate change is
happening now. It cannot be ignored.
Over the past century around the UK we have seen sea levels rise and
more of our winter rain falling in intense wet spells. Seasonal rainfall
is highly variable. It seems to have decreased in summer and increased
in winter, although winter amounts changed little in the last 50 years.
Some of the changes might reflect natural variation; however the
broad trends are in line with projections from climate models.
Greenhouse gas (GHG) levels in the atmosphere are likely to cause
higher winter rainfall in future. Past GHG emissions mean some
climate change is inevitable in the next 20-30 years. Lower emissions
could reduce the amount of climate change further into the future,
but changes are still projected at least as far ahead as the 2080s.
We have enough confidence in large scale climate models to say
that we must plan for change. There is more uncertainty at a local
scale but model results can still help us plan to adapt. For example
we understand rain storms may become more intense, even if we
can’t be sure about exactly where or when. By the 2080s, the latest
UK climate projections (UKCP09) predict that there could be around
three times as many days in winter with heavy rainfall (defined as
more than 25mm in a day). It is plausible that the amount of rain in
extreme storms (with a 1 in 5 annual chance or rarer) could increase
locally by 40%.
One example of climate change occurring is the increasing frequency
of closures of the Thames Barrier. This clearly shows four closures in
the whole of the 1980s, rising to 19 separate closures in 2003 alone
and five for just the first three months of 2010.
22 • Local flood risk management strategy • Climate change
Thames Barrier Closures 1983 – 2010 4
Year
1983
Closures due to
Tidal flooding
Fluvial flooding
1
0
Total closures
1
1984
0
0
0
1985
0
1
1
1986
0
0
0
1987
1
0
1
1988
1
0
1
1989
0
0
0
1990
3
3
6
1991
0
0
0
1992
0
1
1
1993
5
4
9
1994
1
0
1
1995
3
2
5
1996
4
0
4
1997
0
0
0
1998
3
0
3
1999
3
3
6
2000
4
6
10
2001
11
4
15
2002
2
2
4
2003
11
8
19
2004
2
0
2
2005
5
0
5
2006
1
0
1
2007
11
0
11
2008
3
0
3
2009
1
4
5
2010 (up to 20 March)
0
5
5
Total
76
43
119
The future:
The current National Planning Policy Framework is likely to be
replaced. Following an external review, ministers have proposed a
new streamlined planning practice that will provide support for the
growth and creation of jobs and homes that the country needs. It will
also provide clearer protections for our natural and historic
environment by giving power back to communities who are generally
best placed to make local decisions.5 This is currently in the public
domain for consultation and comment.
In order to allow consideration of the effects of climate change, Map
Set 1E of the Partnership for Urban South Hampshire Strategic Flood
Risk Assessment shows revised outlines for Flood Zones 2 and 3 for a
number of years over the next century. The outlines were produced
for 2025, 2055, 2085 and 2115. This is in line with recent Defra
guidance on climate change, which provided allowances for sea level
rise to 2025, 2055, 2085 and 2115 and indicative sensitivity ranges
for increased river flows due to climate change from 2025 onwards.
In tidal areas, these climate change outlines were derived by
projecting the Environment Agency extreme sea levels inland, using a
methodology defined by the Environment Agency.
The map here shows the extent of Flood Zone 2 or 3 in the year
2115, given the predicted impacts of climate change. Although
planning decisions are taken using the present day Flood Zones,
PPS25 states that flood risk should be considered throughout the
lifetime of a development. In certain areas, climate change may mean
that the flood zones could encroach upon areas that would otherwise
be considered suitable for development. This may be an important
issue for local planning authorities. At the sub-regional scale, the
climate change outlines can be used to show which areas of the
sub-region are most vulnerable to rising sea levels, indicated as those
areas where there is greater variation between each climate change
outline from 2025 to 2115.
Climate change • Local flood risk management strategy • 23
Citywide flood risk measures
Portsmouth City Council departments that help reduce
flood risk and how
Portsmouth City Council has a number of measures in place to
mitigate the risk of flooding. These range from planning policies to
management and reactive actions in response to a flood event.
PCC seafront management
The Seafront Masterplan is intended to guide improvements to
the seafront area of the city, which stretches for 3.7km between
Portsmouth and Langstone Harbour entrances. It contains proposals
that respond to the overarching vision and aims of the Seafront
Strategy. In the context of the Local Flood Risk Management Strategy,
‘the plan seeks to establish a high quality baseline for proposals
including design principles …’
It is anticipated that detailed
proposals for enhanced coastal
defences at the seafront will be
informed by the masterplan which
identifies opportunities to utilise
coastal defence structures to deliver
wider benefits to the public in
terms of amenity and aesthetics.
The Seafront Masterplan is wholly
within Flood Cell 1 of the Portsea
Island Coastal Strategy, which has
attracted funding for improved sea
defences.
Colas (contractors working with
PCC on PFI agreement)
• Gully cleansing programme,
especially in autumn leaf fall
period.
• Maintain PCC owned drainage
assets e.g. highway drainage.
• Coastal flooding response team
for the Coastal Partnership.
24 • Local flood risk management strategy • Citywide flood risk measures
PCC Drainage Team
The act imposes a number of new duties on PCC as a Lead Local
Flood Authority. The Drainage Team undertakes many of these duties.
Other duties:
Statutory duties:SURFACE WATER FLOODING NOTES
• Respond to flooding incidents in the city.
• To prepare a Local Flood Risk Management Strategy (FWMA S9).
• Vital role in setting up and running of the emergency response
room during heavy rainfall events and co-ordinating the response
with contractors.
CITY OF PORTSMOUTH
Rain event of 6 October 2014



• To investigate flood incidents (FWMA S19).


• To establish and maintain a register of structures that affect flood
risk (FWMA S21).



• To designate third party assets that affect flood risk and give notice
to owners that they have been designated (FWMA Schedule 1).









• Responsible for consenting and enforcing works on ordinary
watercourses (FWMA Schedule 2 Para. 33).



• Prepare a Flood Hazard map (FRR Part 3).





















• Work with Eastern Solent Coastal Partnership in overlapping
matters.
• Assist TES Major Projects with drainage requirements (Technical
advice and Guidance – e.g. Tipner, Northern Road Bridge).
• Act as a liaison between Southern Water, the Environment Agency,
PCC departments and elected members (e.g. Southern Water
surface water separation schemes).

• Prepare a Flood Risk Management Plan (FRR Part 4).

• Seek external funding through Environment Agency Flood Defence
Grant in Aid (FDGiA) scheme for major schemes.
• Design solutions to improve the drainage capability of the city.
• New role as SuDS Approval Body (SAB) requiring LLFA to approve,
adopt and maintain SuDS on new developments (FWMA Schedule 3).

• Checking areas of the city susceptible to flood risk.






• Work with Colas to identify localised flooding and suggest possible
remediation / mitigation measures.
• Increase resident understanding of local flood risk.
• Increase our historic knowledge of Portsmouth drainage in liaison
with the central library and city museum.
• Continue works as a shared service with Southampton City
Council and Isle of Wight.
• Respond to residents’ enquiries with regards to flood and drainage.
• Promote SuDS.

• Promote schemes which reduce flood risk.





 
• Promote Flood Action Group (FLAG) schemes with the EA.
• Investigate unresolved flooding issues


© Crown Copyright and database
right 2014. Ordnance Survey licence number 100019671.
POINTS ADDED SINCE 5jan2012 MAP
23c - London Road at bus stops outside 99p shop
23d - Emsworth Road








Citywide flood risk measures • Local flood risk management strategy • 25
The Eastern Solent Coastal Partnership
The Coastal Partnership was formed through a shared service
agreement signed in April 2012 between the four local authorities of
Portsmouth City Council, Havant Borough Council, Gosport Borough
Council and Fareham Borough Council.
The Coastal Partnership’s work, on behalf of the council is:
Reduce the risks to people and the developed and natural
environment from flooding and coastal erosion by encouraging the
provision of technically, environmentally and economically sound
and sustainable defence measures along the entire 162km coastline
contained within the Coastal Partnership’s authority boundary. This is
achieved by undertaking a number of functions:
• ensure the development of strategic plans for the future
management of the coastline and ensure their implementation.
• ensure that any development within the coastal zone does not
adversely effect the environment.
The Coastal Partnership surveys and carries out research relating to
coast protection and sea defence; designs and supervises new sea
defence and coast protection projects; arranges and supervises coastal
protection works and advises private individuals on minor problems
with coast protection and flooding where these are the consultee’s
responsibility.
The Coastal Partnership maintains this with the help of land owners
whose land adjoins the shoreline.
The Coast Protection Act 1949 and the Land Drainage Act 1991,
provide maritime Councils with permissive powers to carry out coastal
defence works. Coastal defence is an encompassing term for both
‘coast protection’ and ‘sea defence’; where coast protection is the
protection of the land from the risk of erosion and sea defence is the
defence against the risk of flooding by the sea.
• monitoring the evolution of the coastline and the forcing
parameters affecting it.
A major task is the production of Management Plans in association
with the Environment Agency (EA). Shoreline Management Plans,
Flood and Coastal Erosion Risk Management Strategies and Beach
Management Plans contribute to the continuing maintenance of
the Borough’s assets and protection of property. The Plans are used
to provide the framework within which maintenance works and
new schemes are identified and prioritised. The Department for
Environment, Food and Rural Affairs ( DEFRA ) can award Capital
Grant towards Strategies, preliminary studies and Capital Schemes.
The Coastal Partnership also works to protect assets against coastal
erosion and flooding from the sea, without conflicting with the above.
More information about the Eastern Solent Coastal Partnership can
be found at the following link: www.escp.org.uk
• ensure that any development within the coastal zone does not
disrupt natural processes, such as the transport of sediment along
the shoreline.
• avoid committing future generations to inflexible and expensive
options for coastal defence.
PCC planning
The Portsmouth Plan, the strategy for development in the city up to
2027, includes two specific policies that influence how flood risk is
considered in new development:
• Requiring surface water to be separated within the site and the post
development rate of discharge of both surface and foul water to the
combined system should be no greater than the existing rate.
Policy PCS12 (Flood Risk) confirms that the council, in planning
future development in the city, will follow the flood risk management
hierarchy establish in Planning Policy Statement 25: assess, avoid,
substitute, control, mitigate. This applies both to plan making and to
the determination of planning applications. The council through this
policy has committed to:
• Mitigating the residual flood risk that remains after other steps
have been considered by ensuring that the design and layout of
development minimises the risk to people and damage to property
in the event of flooding and having in place effective emergency
response plans.
• Assessing the level of flood risk in making allocations for
development, and avoid flood risk by prioritising those sites for
development which are at lower risk of flooding.
• Assessing the level of flood risk in considering planning
applications and requiring the development to demonstrate that it
will be safe over its lifetime. Where necessary, controlling flood risk
on individual sites through on site flood risk management
measures.
• Maintaining and improving the city’s flood defences; and seeking
contributions towards flood defences from development.
• Seeking opportunities to improve the capacity problems of the
existing sewer system, including through the promotion of a link
separating the mainland waste water from Portsea Island wastewater.
• Permitting new developments only where the necessary surface
water drainage, foul drainage and sewage treatment capacity is
available, or where additional capacity will be provided in time to
serve any individual phase of the development without
unacceptably reducing the level of service to existing users, or
causing harm to the environment.
Other policies in the Portsmouth Plan also contribute, more indirectly,
to the management of flood risk: Policy PCS15 – Sustainable Design
and Construction expect new development to meet BREEAM or
Code for Sustainable Homes standards, which include measures on
water efficiency, flood risk and drainage; and Policy PCS13 – Greener
Portsmouth protects open spaces from development, encourages
green roofs and green walls
in new development and
requires new open space to
be provided in larger new
developments, all measures
The Portsmouth Plan
which help with effective
drainage across the city.
Portsmouth's Core Strategy
The Community Infrastructure
Levy (CIL) is a new levy that
PCC can choose to charge on
new developments in their
area. The money can be used
to support development by
funding infrastructure that
the council, local community
and neighbourhoods want,
this includes flood defence
structures.
www.portsmouth.gov.uk
1
The South East 7
PCC Flood Risk Strategy Group
PCC sits on a panel of LLFAs called the South East 7, which includes
all the unitary and county authorities from the South East stretching
from Hampshire through to Kent. As a joint venture, the SE7 has
delivered a Sustainable Drainage System (SuDS) Masterplanning
Guidance document for all those connected with implementing new
developments. The document is intended to provide a blanket for
SuDS across the whole of the South East, giving consistent guidance
to developers on how to address and choose SuDS under differing
site conditions.
A biannual meeting of Risk Management Authorities held at the
Civic Offices between PCC elected members, strategic directors,
PCC Planning, PCC Drainage, Eastern Solent Coastal Partnership,
Environment Agency and Southern Water to inform and update on
progress in matters relating to flooding.
The SuDS Approval Body
Under the Act, Portsmouth City Council has a duty to implement a
SuDS Approval Body (SAB) which is tasked with reviewing drainage
submissions of new developments. This is in addition to the existing
planning process. The SAB will have the power to refuse a planning
application on drainage grounds alone, and can also inspect the
construction of a drainage system to ensure it is built as designed and
as approved by the SAB. This duty is presently still not enacted, and is
currently under consultation.
Partnership for Urban South Hampshire (PUSH)
PUSH is a partnership dedicated to delivering sustainable, economicled growth and regeneration to create a more prosperous, attractive
and sustainable South Hampshire offering a better quality of life for
everyone who lives, works and spends their leisure time here.
Working in partnership, PUSH is determined to tackle these issues
and bring about a renaissance of the cities of Southampton and
Portsmouth as well as some of our older urban areas.6
Highways
• Incorporate SuDS in all major highway development in conjunction
with LLFA.
• Promote impermeable paving and reduce hard standing areas.
• Work with Southern Water to reduce water flow into sewers.
Civil Contingencies Unit
• Preparation of Multi Agency Flood Plan and Flood Response Plan.
• Inform the public on how to prepare for and manage a flood
event.
• Circulate Met Office weather warnings.
FRP June 2009, due for review 2014
MAFP June 2011, due for review 2014
Business as usual functions of Portsmouth City Council and their potential water environmental impacts
The table below shows how activities can affect water quality in bodies, like the harbours.7
Local authority
functions and
services
Point source
pollution
Local planning
policies
Urban diffuse pollution
Polluted runoff
from
impermeable
urban surfaces
Drainage/
sewerage e.g.
misconnections,
etc
Sediment run-off
from land e.g.
pollution down
surface water drains
◊
♦
◊
◊
Determination of
planning
applications and
building control
inspections
◊
♦
♦
♦
Local authority
drainage and flood
risk management
functions, and future
SuDS approval body
role
◊
♦
♦
♦
Environmental
health and pollution
control functions
◊
Managing local
authority buildings
and assets
◊
♦
Littering,
dumping and
general neglect
of watercourses
◊
♦
♦
◊
♦
Highways design,
maintenance and
cleansing operations
♦
◊
Local authority
community
leadership and
advocacy roles,
including education
♦
♦
♦
Low flows
in water
bodies
Habitat
degradation
e.g. invasive
non-native
species
♦
◊
◊
◊
♦
◊
◊
◊
♦
◊
◊
♦
♦
Open space and
green infrastructure,
ecology and
recreation
Pollution from
contaminated land,
including disturbance
during development
Physical
man-made
modifications
to water
bodies
Rural diffuse
pollution e.g.
from
agriculture,
septic tanks, etc
♦
♦
◊
◊
◊
◊
◊
◊
♦
◊
◊
◊
◊
◊
◊
◊
◊
◊
♦ = has significant potential effect on causes of poor water body status
◊ = has less significant potential effect on causes of poor water body status
The Environment Agency
Environment Agency main rivers
The Environment Agency is responsible for managing warnings of
potential tidal and fluvial flooding. The flood warning system is
based on geographical flood warning areas and indicates the level of
predicted risk. It advises the public and responders on the likelihood of
flooding through a staged approach to warning and taking action. The
Environment Agency has split the coastal floodplain in Portsmouth into
warning areas, based on the level of defences and flood risk.
The Environment Agency uses three flood codes to indicate the level
of predicted risk: flood alert, flood warning and severe flood warning.
Flood warnings are issued directly to the public, responders and the
media through a 24-hour warning system called Floodline Warnings
Direct. If a flood warning or severe flood warning is issued in the
Portsmouth area a recorded message is sent directly to all landline
numbers, including ex-directory, in that flood warning area. Members
of the public and businesses can also sign up to receive warning
messages through phone, fax, text, email or pager. Members of
the public can also call the EA 24-hour phone line Floodline service,
where they can listen to recorded information about flood warnings
in force or speak to an advisor on 0845 988 1188.
When the flood threat has receded the EA will issue Warning
Removed messages. This will tell people the flood threat has passed
and no further flooding is expected in their area. They will be issued
through Floodline Warnings Direct, Floodline and the internet.
The Environment Agency is the operating authority for flood defences
on designated main rivers:
• River Wallington (tidal) – flows
• Great Salterns Drain
into Portsmouth Harbour
• Great Salterns Drain (tidal)
• Farlington Marsh Gutter
• Farlington Marsh Gutter (tidal)
• Hermitage Lake (tidal) – flows
into Langstone Harbour
© Crown Copyright and database right 2013.
Ordnance Survey licence number 100019671.
Reducing the risk of flooding
Protecting the environment
• Building river and sea defences.
• Ensuring that farms, factories and other businesses don’t release too
many chemicals into the air, rivers and streams or land. We work with
people to help them meet their legal responsibilities, and we prosecute
anyone who wilfully breaks the law and damages the environment.
• Warning when flooding is expected from rivers or the sea.
• Helping people understand what they can do to protect
themselves and their property from flooding.
• Helping the emergency services during a flood.
• Working with local councils and water companies to reduce the
risk of flooding from heavy rainfall.
• Advising local councils on whether proposals for new buildings will
increase the risk of flooding.
• Using science and research to identify areas at risk from flooding
and plan the best ways of reducing flooding in the future.
• Advising government on policies affecting the risk of flooding.
• Working closely with the Met Office, who provide weather
forecasts and warn when heavy rain is expected.
• Licensing waste processing centres, such as recycling centres,
rubbish dumps and waste incinerators. Before granting a licence,
we assess whether they meet strict environmental standards, and
then we make sure they continue to meet them.
• Licensing the removal of water from rivers and underground, to
make sure there is enough water for wildlife as well as for homes,
farms, factories and other businesses. Every drop of water you use
at home and work is taken from the environment, and we make
sure water companies are able to supply their customers without
harming the environment.
• Carrying out scientific research to set standards for the quality of air,
land and water, and prove whether these standards are being met.
Our advice to government and businesses is based on sound science.
Improving the environment
• Cleaning up after major pollution incidents, such as chemical spills
on land or in rivers, and cleaning up places damaged by industry
or neglect in the past.
• Working with conservation organisations to create and restore
important wildlife habitats, and protect the plants and animals that
live in them. Habitats include rivers, ponds, pastures, marshes,
mudflats and woods.
• Licensing fishing by rod in all of England and Wales. The fees help
pay for work to make rivers a healthy place for fish and other
wildlife to live, and mean that people can continue to enjoy fishing.
The Environment Agency responding on site to a flood event © Eastern Solent Coastal Partnership
• Licensing boating for the Thames and some rivers in Kent and East
Anglia. We charge boat registration fees to help pay for work to
keep these waterways open for boats to use.
Adapting to climate change
Substantial flood risk
New flood defences must be able to cope with future rises in sea levels,
as well as current conditions. Science is at the heart of everything we
do, and our plans are based on solid scientific research.
• Issue flood warnings to professional partners, media and at risk
members of the public via Floodline Warnings Direct.
Reporting incidents and emergencies
The EA deals with things that affect the natural environment. Other
organisations deal with buildings, roads, the water supply and
keeping the neighbourhood safe and clean.
Business as usual
• Prepare and maintain Hampshire Local Flood Warning Plan.
• Contribute to multi-agency plans.
• Maintain EA duty officer procedures.
• Update flood risk maps for coastal and fluvial flooding.
• Maintain EA flood defence.
• Contact Response Working Group Local Resilience Forum partners
to discuss activation of Adverse Weather Office.
Severe flood risk
• Issue Severe Flood Warnings to professional partners, media and at
risk members of the public via Floodline Warnings Direct.
• Contact police and other partners to discuss activation of the
Strategic Control Group.
Flood waters receding
• Review EA duty officer procedures.
• Record locations of coastal/fluvial flooding.
• Advise on waste disposal issues.
• Maintain and operate Eastern Road pumping station.
EA live flood warnings link
• Maintain and clear grills on Great Salterns Lane.
Go to www.environment-agency.gov.uk and search ‘live flood
risk map’.
• Monitor fluvial and coastal conditions.
• Respond to pollution incidents.
Moderate flood risk
• Issue Operational Instructions to Portsmouth City Council
indicating levels reached for gate closure.
• Issue Flood Alerts to professional partners on flood risk.
Strategic overview:
• Co-ordinating flood and coastal erosion risk management activities.
• Provide flood warning service.
• Support emergency responders during a flood.
• Provide advice to professional partners on flood risk.
• Managing flood risk from main rivers, estuaries, the sea and
reservoirs.
• Consider contacting Response Working Group Local Resilience
Forum partners to discuss activation of Adverse Weather Office.
• Planning flood risk management activities.
• Record details of flood events
• Power to undertake works to reduce flood risk.
• Power to designate features.
Hampshire Constabulary
Responding to a severe flood event.
• Activate Hampshire and Isle Of Wight (HIOW) Local Resilience
Forum (LRF) strategic multi-agency management.
• Provide chair of Strategic Control Group (SCG).
• Co-ordinate media and public information in accordance with
HIOW LRF Media Plan for Major Incidents.
• Liaise with Highways Agency, local highways authorities and
co-ordinate resources to minimise disruption on the highways and
maximise emergency services access.
• Assist with co-ordinated risk assessed evacuations.
• Set up casualty bureau documentation teams as appropriate.
• Notify Special branch who will assess the potential impact on any
Critical National Infrastructure sites within HIOW.
Hampshire Constabulary responding to a flood event © The Eastern Solent Coastal Partnership
Hampshire Fire and Rescue Service
Responding to a severe flood event:
• Activate HIOW LRF strategic multi-agency management.
• Assist in the co-ordination of media and public information in
accordance with HIOW LRF Media Plan for Major Incidents.
• Continue with co-ordinated risk assessed evacuations, implement
long term flooding protocols.
Hampshire Fire and Rescue Service clearing a flood in The Phoenix’s basement, Duncan Road, Southsea
Southern Water
Southern Water collects and treats waste water (including surface
water) in Portsmouth. It owns and maintains a range of assets which
are essential to effective flood risk management in the city. These
assets themselves may be affected by surface water and groundwater
flooding in some instances. Southern Water is the licensed sewerage
undertaker regulated by the Environment Agency and, financially
regulated by Ofwat.
Southern Water is expected to take a lead in resolving all failures of the
sewerage service irrespective of cause. SW will liaise with other agencies
as necessary to effect a solution leading to a number of partnership
schemes with both surface water and sewerage benefits in due course.
Responding to a severe flood event
• Implement incident team.
• Incident team liaise with police and Portsmouth City Council to
implement appropriate multi-agency level of management.
A petrol interceptor being installed, Copnor Road scheme
• Activate severe weather plan.
• If activated, send representative to SCG.
• Increase standby staff if possible.
• Check plans for detailed actions for high risk assets/areas.
• Provide advice to the public as developed and agreed by the STAC.
Surface water separation
Southern Water has delivered a £20m investment, which included
surface water separation schemes to reduce the risk of sewer flooding
in parts of Portsmouth and Southsea. The scheme diverts a significant
amount of rainwater away from combined sewers by sending it to
the sea, as well as refurbishing some of the existing equipment on the
network, including the construction of two new underground pumping
stations. This work benefits the whole city but in particular, those areas
that have suffered flooding in the past.
The new well in Stamshaw Park, Gruneisen Road scheme
Flood risk ward by ward
How to use the ward pages
Abbreviations
Our strategy has taken the approach of considering each of the 14
wards individually for ease of reference. The information for each
ward has been set out as follows:
PEMS: Portchester Castle to Emsworth Coastal Strategy
PICSS: Portsea Island Coastal Strategy Study
SWMP: Surface Water Management Plan
FBC: Fareham Borough Council
HA: Highways Agency
HWT: Hampshire and Isle of Wight Trust
Ward name
Brief overview of the ward
characteristics including some of
the defining areas
Baffins
Baffins ward is located on the eastern side of Portsea Island and is
predominantly of low topography. There are large open spaces in the
form of the southern side of Great Salterns golf course, Milton
Common, allotments and various other green spaces. The developed
area is largely set back from the coast to the west of Eastern Road. The
coastline runs from the Harvester to Milton Common on Langstone
Harbour frontage. The ward also includes Great Salterns Lake which
acts as the main surface water drainage outlet for approximately one
quarter of Portsea Island. The lake and its tributary culvert feeding into
it from the golf course to the north are designated as a main river. It
has pumps which trigger at a certain water level in times of high tide.
Flooding
Baffins ward has a number of separate surface water drainage
networks but is largely served by combined drainage networks.
Baffins ward forms part of two separate areas identified for targeted
groundwater investigation.
There are a few pockets of surface water flooding recorded, and there
have been incidents of wave overtopping along the Eastern Road
frontage which causes disruption to one of the arterial roads of
Portsmouth. It is highly likely that there was groundwater influence
on one of the more recent events.
This area features in the Portsea Island Coastal Strategy Study –
actions are outlined on the next page.
Brief overview of the ward drainage
and coastal characteristics, and an
overview of flooding that has
occurred historically
4j
Key
Aerial shot of the ward showing
Surface Water Management Plan
Local Flood Risk Zones, areas
identified for groundwater
investigation and coastal flood cells
8
PICSS flood cell 4
areas targeted for
groundwater investigation
Ward boundary
SWMP hotspots
Photo showing an example of flooding
or flood aftermath within the ward
5
4i
4
3h
Wave overtopping along the Eastern Road frontage
38 • Local flood risk management strategy • Baffins
Coastal
Overlap
Sea defence
with other
type(s)
wards
Area
Coastal flood risk table with actions, responsible authority and funding information
Residential
properties presently
at risk (0.5% annual
probability flood)
Background information
Milton Bund to
Tangier Road
seawall (4i)
n/a
Seawalls,
revetments,
embankments
Frontage protects to residential properties
and Milton Common (former landfill site).
Existing standard of protection 0.5%)
Eastern Road
bridge to Great
Salterns Quay (4j)
Copnor
Seawalls,
revetments
Frontage protects to A2030, golf course,
housing estate and some commercial
properties. Existing standard of protection
0.5%.
23
Proposed measures (target standard
of protection 0.5%)
Responsible
authority
Completion
Funding
date
Raise crest wall and embankment,
provide shoreline protection
PCC
2017
Flood
Defence
Grant in Aid
PCC
Strengthen existing walls and raise
defences to provide a sustained
standard of protection accounting for
sea level rise.
2017
Flood
Defence
Grant in Aid
Surface
Surface water flood risk information with actions
Surface water
management
plan area
Overlap
with other Background information
wards
Properties presently at risk (1%
annual probability rain event)
Project lead
Commercial
Historic
flood
records
Proposed measures
Residential
8 – Great
Salterns golf
course
n/a
Golf course regularly floods when EA main river
running through the centre of the course bursts its
banks
1
11
Good
Great Salterns Scheme addressing the
issues. Additional storm water channel,
additional culvert and upgrade of existing
pumping station
Southern
Water
by 2015
Southern Water have identified a scheme to remove
surface water from the combined sewer network
n/a
n/a
Some
Tangier Road Scheme under construction
Southern
Water
by 2015
1
11
Tangier Road n/a
(not in SWMP)
Total
Completion
date
Groundwater
Areas identified for groundwater investigation and monitoring
Groundwater
desktop study
targeted area
Overlap
wards
Proposed measures
Project lead
5 – Great
Salterns
Copnor
Low topography, likely to have high groundwater table.
Highlighted as susceptible to groundwater emergence due
to a geological permeability boundary
Determine and agree with partners how
best to gather groundwater information
and exactly where within the area
PCC with support requested from Environment
Agency, Southern Water, PCC planning
department, Eastern Solent Coastal Partnership
end 2014
4 – Milton
Milton
Determine and agree with partners how
best to gather groundwater information
and exactly where within the area
end 2014
Stanley Avenue
n/a
Flooding to garages along the rear access road.
Investigations have found that the likely source is
groundwater with 95% surety.
PCC is investigating possibilities
PCC
end 2014
Completion
date
Baffins • Local flood risk management strategy • 39
NOTE: Only short term actions are shown as the strategy is due to be reviewed in 2018. For medium and long term actions please refer to PICSS / PEMS.
Flood risk ward by ward • Local flood risk management strategy • 35
Paulsgrove
Paulsgrove ward is dominated by the side of Portsdown Hill and the
M27 which splits the densely populated area into two sections. There
are large open spaces towards the top of the hill, King Richards and
St Pauls schools, Port Solent and along Southampton Road frontage.
The south coast railway line runs through the south of the ward. The
coastline is wholly within Portsmouth Harbour and includes Trafalgar
Wharf, Southampton Road, Port Solent and Horsea Island.
Flooding
Paulsgrove has largely separate surface water drainage networks with
sparse records of surface water flooding, most of which are likely to
be caused by localised issues like blocked gullies.
There have been historical incidents of wave overtopping along
Southampton Road frontage which causes localised disruption to
traffic and residential areas along the frontage.
The area to the south of the railway line has been identified for
targeted groundwater investigation.
This area features in the recently approved Portchester Castle to
Emsworth Coastal Strategy – actions are outlined on the next page.
Key
PEMS flood cell 1a
Ward boundary
PEMS flood cell 1b
PEMS flood cell 2
areas targeted for
PEMS flood cell 3
SWMP hotspots
1
11
Southampton Road frontage after a combined high tide and storm event
36 • Local flood risk management strategy • Paulsgrove
Coastal
Overlap
Sea defence
with other
type(s)
wards
Area
Dwellings presently
at risk from a 0.5%
annual probability
flood event
Proposed measures
Responsible
authority
EA/English
Heritage/
PCC/FBC
Portchester
to
Paulsgrove
(Reach 1)
Fareham
Borough
Council
Concrete wall,
concrete bag
wall, revetment,
embankment
and sheet piling
Frontage provides protection to
residential and commercial
properties and A27. Defences in
good to fair condition. Present
standard of protection 5-10%
66 (408 across
entire flood cell)
Raise defences to interim
height from Portchester Castle
to Paulsgrove
Horsea
Island
(Reach 2)
n/a
Concrete block
revetment (Port
Solent), Gabions
(MoD and
landfill site)
Frontage provides erosion
protection to landfill site.
Defences in very good to good
condition. Present standard of
protection <0.5%
0
Maintain current defences with PCC/MoD
replacement, refurbishment
and general repairs as required
Completion
date
Funding
Medium likelihood of funding
through Flood Defence Grant in Aid.
Contributions likely to be required.
Any development of the Trafalgar
Wharf site, included in the draft Site
Allocations document, could be a
potential source of funding
Works
required by
2020
MOD
ongoing
Surface
Surface water
management
plan area
Overlap with
other wards
none
n/a
Historic flood
records
Proposed measures
Project lead
Completion
date
Low surface water flood
risk. Potential for high
velocity overland flows
due to hill topography
n/a
n/a
Residential
Commercial
EA AStSWF map shows railway line acts as a
bund trapping water. Very little evidence to
support this
0
0
Proposed measures
Project lead
Highlighted as susceptible to groundwater
emergence due to a geological permeability
boundary
Gather information relating to groundwater levels,
contaminants, sewer infiltration, sea defence
integrity and ground infiltration rates, for sharing
among partner organisations, internally to PCC and
property developers. Will result in a groundwater
trend report for the city of Portsmouth
PCC with support requested from
Environment Agency, Southern Water, PCC
planning department, Eastern Solent
Coastal Partnership
Sparse
Groundwater
Groundwater
desktop study
targeted area
11 –
Cosham and
Paulsgrove
Overlap with
other wards
Cosham
Completion
date
2020
Paulsgrove • Local flood risk management strategy • 37
Cosham
Cosham ward is dominated by the south side of Portsdown Hill and
the railway line dissects the area. There are large open spaces towards
the top of the hill, King George playing fields and the Lakeside
commercial development.
The coastline runs along the south side embankment of the M27
and is wholly on the north side of Portscreek which separates the
mainland from Portsea Island and connects Langstone and
Portsmouth Harbours.
Flooding
Cosham has a number of separate surface water drainage networks along
with a number of combined drainage networks. There are some localised
records of surface water flooding, most of which are caused by localised
issues like blocked gullies or overland flows from the hill.
There have been very few historical incidents of wave overtopping along
the M27 frontage which acts as a barrier. The area to the south of the
railway line has been identified for targeted groundwater investigation.
There is potential for tide-locking to occur, however there are very few
instances where this is thought to have contributed to flooding.
This area features in the recently approved
Portchester Castle to Emsworth Coastal Strategy
– actions are outlined on the next page.
Key
PEMS flood cell 3
Ward boundary
areas targeted for groundwater
investigation
SWMP hotspots
1
11
10
A localised surface water flood event in Cosham ward
38 • Local flood risk management strategy • Cosham
Coastal
Overlap
Sea
with other defence
wards
type(s)
Area
(Part of)
M27 and
Farlington
(Reach 3)
Drayton
and
Farlington
Concrete
block
revetment
M27 frontage provides protection to strategic
infrastructure of M27/A27 and the South Coast railway.
Refurbishment works recently completed by the Highways
Agency means the condition of the revetment here is
currently good. Current standard of protection <0.1%
Residential properties
probability flood event)
Proposed measures* (target
standard of protection <0.1%)
Responsible
authority
Funding
Completion
date
1863
Maintenance of M27 revetment
HA
HA
Ongoing
*Refer also to measures required for overlapping wards due to interdependency of flood cells
Surface
Surface water
management
plan area
Overlap with
other wards
1–
Cosham
Drayton and
Farlington
Historic flood
records
Proposed measures
Project lead
Completion
date
Area considered too large
to treat as one group.
Further investigation
needed
PCC
ongoing
Residential
Commercial
EA mapping shows railway line acts as a
bund trapping water. Very little evidence to
support this. A recent flood event in this area
is not thought to have been influenced by the
railway line
481
90
Proposed measures
Project lead
boundary
Environment Agency, Southern Water, PCC
planning department, Eastern Solent
Coastal Partnership
Sparse
Groundwater
Groundwater
desktop study
targeted area
11 –
Cosham and
Paulsgrove
Overlap with
other wards
Paulsgrove
Completion
date
2020
Cosham • Local flood risk management strategy • 39
Drayton and Farlington
Drayton and Farlington ward is dominated by the south side of
Portsdown Hill and Farlington Marshes to the south. There are
large open spaces towards the top of the hill in the area of the
underground reservoirs and Farlington Marshes itself, which is
dissected by the A27. The developed area is largely to the north of
the railway line which runs along the north side of the marshes. The
coastline runs partly along the south side embankment of the M27
and around Farlington Marshes and is partly on the north side of
Portscreek and partly Langstone Harbour.
Flooding
The ward has a number of separate surface water drainage networks
along with a number of combined drainage networks. There have
been a number of recent flooding events which affected some
residential properties and these have been well documented.
There have been very few historical incidents of wave overtopping
along the M27 frontage, while the marshes are allowed to flood at
high tide events due to their importance for rare bird species.
The area around the north of Farlington Marshes has been identified
for targeted groundwater investigation.
It is likely that a combination of factors contributed to the three recent
flood events at the same location in the ward, including groundwater,
tidal influence, rainfall and inability for the sewerage system to cope.
Investigations by PCC and Southern Water are ongoing.
This area features in the recently approved Portchester Castle to
Emsworth Coastal Strategy – actions are outlined overleaf. Work
on the Farlington Marshes coastal defences are ongoing with the
Environment Agency and the Eastern Solent Coastal Partnership on
behalf of PCC.
Key
1
11
PEMS flood
cell 3
10
Ward boundary
2
areas targeted
for groundwater
investigation
SWMP
hotspots
A recent flood event in Drayton and Farlington ward
40 • Local flood risk management strategy • Drayton and Farlington
Coastal
Area
(Part of)
M27 and
Farlington
(Reach 3)
Overlap
Sea
with other defence
wards
type(s)
Drayton
and
Farlington
Concrete
block
revetment
Residential
properties
at risk
1449
M27 frontage provides protection to
strategic infrastructure of M27/A27 and
the railway. Refurbishment works mean
the condition of the revetment is good.
Current standard of protection <0.1%.
Farlington frontage provides protection
to the Farlington Marshes SPA. Defence
condition is poor – regular overtopping
occurs, and repair/maintenance required
annually. Standard of protection 20%
Proposed measures (target standard of protection
<0.1% at M27; 20% for 20 years at Farlington)
Responsible
authority
Funding
Completion
date
HA
HA
Ongoing
Maintenance of Farlington Marshes revetment
EA in the
short term
EA
Ongoing
Provision of vehicle underpass flood gate and culvert
flaps beneath A27 at Farlington Marshes
PCC/EA/
HWT
Flood Defence
Grant in Aid
secured
Completed
Undertake Solent-wide study to identify economic,
environmental and social impacts of either improving
existing revetment at Farlington Marshes, or undertaking
managed realignment
EA/PCC/HA
High probability
of attracting
Flood Defence
Grant in Aid
Required by
2020
Surface
Surface water
management
plan area
Overlap
wards
Residential
Commercial
Historic
flood
records
1–
Cosham
Cosham
EA mapping shows railway line acts as a bund
trapping water. Very little evidence to support this.
A recent flood event in this area is not thought to
have been influenced by the railway line
481
90
Sparse
Area considered too large to treat as one group.
Further investigation needed
The marshes act as a drain to a number of
properties in the Drayton and Farlington areas.
Ditch clearance work undertaken October 2014.
Further ditch clearance work proposed for winter
2015/16
0
4
Sparse
PCC/EA
Clearance of surface water pathways.
Environmental designations and the importance of
the marshes as a wetland habitat for bird species
may restrict work
Partially
completed
PCC/
PCC and Southern Water are investigating the
cause with a view to providing a long term solution. Southern
Water
Temporary pumps are in place until permanent
pumps are planned to be installed in 2015
ongoing
2 – Farlington n/a
Marshes
Station Road
(not in
SWMP)
50
Three separate flood incidents in the winter of
2012/13. Extends to over 50 properties. Manhole
surcharge witnessed on each occasion. Exact cause
not yet known
n/a
Total
531
0
Very
good
Proposed measures
Project
lead
Completion
date
PCC
ongoing
To complete
Oct 2015
94
Groundwater
Groundwater desktop
study targeted area
Overlap with
other wards
10 – Farlington
(excluding marshes
south of A27)
n/a
Proposed measures
Low topography, likely to have high groundwater
table. Highlighted as susceptible to groundwater
emergence due to a geological permeability boundary integrity and ground infiltration rates, for sharing
Project lead
Environment Agency, Southern
Water, PCC planning department,
Eastern Solent Coastal Partnership
Completion
date
2020
Drayton and Farlington • Local flood risk management strategy • 41
Hilsea
Hilsea ward is located in the northwest corner of Portsea Island and is
form of Alexandra Park, various playing fields and around the Hilsea
Lines scheduled ancient monument.
The developed area is largely set back from the coast. The coastline
runs from the Mountbatten Centre on Tipner Lake to the railway
bridge on the south side of Portscreek.
Flooding
Hilsea ward has a number of separate surface water drainage
networks along with some combined and a small number of privately
owned drainage networks. There have been very few historical
incidents of wave overtopping along the frontage which is well
sheltered by the motorway embankments of the M27 and M275.
Hilsea ward forms part of two separate areas identified for targeted
There have been a number of recent flooding events which affected
some private properties externally and these have been well
documented. It is likely that a number of factors have contributed to
the flooding including defective sewer systems, groundwater,
impermeable ground, rainfall and tide-locking. PCC and Southern
Water are working together to investigate and take corrective actions.
11
4k
4l
3
7
6
Key
PEMS flood
cell 3
PICSS flood
cell 4
8
5
6
Ward boundary
areas targeted
for groundwater
investigation
10
SWMP
hotspots
Wave overtopping at Alexandra Park
42 • Local flood risk management strategy • Hilsea
Coastal
Area
Overlap
Sea
with other defence
wards
type(s)
Portscreek Copnor
South (4k)
Residential
properties at risk
(0.5% annual
probability flood)
Seawalls,
revetments
Frontage provides protection to commercial and residential
properties, and Hilsea Lines scheduled ancient monument. Existing
standard of protection 10%
Hilsea
Lido to
Tipner
Lake (4l)
n/a
Seawalls,
revetments
Frontage provides protection primarily to residential properties.
Existing standard of protection 10%
(Part of)
M27 and
Farlington
(Reach 3)
Drayton
and
Farlington
Concrete
block
revetment
M27 frontage provides protection to strategic infrastructure of
M27/A27 and the South Coast railway. Refurbishment works
recently completed by Highways Agency means condition of
revetment here is currently good. Current standard of protection
<0.1%
1704
1863
Proposed measures (target
standard of protection 0.5%)
Responsible
Funding
authority
Completion
date
Raise existing embankment and
maintain existing walls and
revetments
PCC
Flood Defence 2015/16
Grant in Aid
Replace existing structures with
higher levels to provide a
sustained standard of flood
protection against sea level rise
PCC
Flood Defence 2025/26
Grant in Aid
HA
HA
Ongoing
Surface
Surface water
management
plan area
Overlap
wards
Residential
Commercial
3 – War
department
sewer
Copnor
Exact location and function of 1920s
sewer is unclear
0
5 – Northern
Parade (Alex
Way area)
n/a
This area is a natural low point and the 0
first point of emergence of flood
waters when the sewer system is at
capacity. Regular flooding to residents’
garages
Historic flood
records
Proposed measures
Project lead
Completion
date
5
Sparse
Further investigation required
PCC/Southern
Water
ongoing
4
Very good
Clearance of blockages in the sewer
network undertaken by Southern Water.
Responsibility for the private sewer has
for the meantime been taken on by PCC/
Colas for maintenance purposes
PCC/Southern
Water
completed
Groundwater
Groundwater
desktop study
targeted area
Overlap
wards
7 – Hilsea
n/a
boundary
8 – Alexandra
Park and Tipner
Nelson
boundary
Completion
date
Proposed measures
Project lead
2020
2020
Hilsea • Local flood risk management strategy • 43
Copnor
Copnor ward is located on the northeast corner of Portsea Island.
There are large open spaces on the northern part of Great Salterns
golf course, various playing fields and a part of Hilsea Lines
scheduled ancient monument. The developed area is largely set
back from the coast and is dominated by the railway line, industrial
estates and Anchorage Park housing estate. The coastline runs from
the railway bridge on the south side of Portscreek to the Harvester
on the Eastern Road.
3
Flooding
Copnor ward has a small number of separate surface water drainage
networks but is dominated by combined drainage networks. There
have been very few historical incidents of wave overtopping along the
frontage which is sheltered by Eastern Road.
Copnor ward forms part of two separate areas identified for targeted
There have been a number of historic flood events which affected
some private property and a main road. It is likely that this is caused
by a fault in the local sewerage network, which Southern Water are
currently rectifying.
4k
Key
4
6
4j
PICSS flood cell 4
areas targeted for
Ward boundary
SWMP hotspots
6
7
9
5
8
4l
Copnor Road affected by surface water
44 • Local flood risk management strategy • Copnor
Coastal
Area
Overlap
Sea
with other defence
wards
type(s)
Residential
probability flood)
Portscreek
South (4k)
Hilsea
Seawalls,
revetments
Frontage protects to commercial and residential
properties, and Hilsea Lines scheduled ancient
monument. Existing standard of protection 10%
Eastern Road
Bridge to
Great Salterns
Quay (4j)
n/a
Seawalls,
revetments
Frontage protects to A2030, golf course, housing
estate and some commercial properties. Existing
standard of protection 0.5%
837
Responsible
authority
Raise embankment and maintain
existing walls and revetments
PCC
Flood Defence
Grant in Aid
2015/16
standard of protection accounting
for sea level rise
PCC
Flood Defence
Grant in Aid
2025/26
Funding
Completion
date
Surface
Proposed measures
Project lead
Commercial
Historic
flood
records
Exact location and function of 1920s sewer 0
is unclear
5
Sparse
Further investigation required.
PCC/Southern
Water
ongoing
n/a
High surface water flood risk due to low
topography and combined drainage system
34
6
Sparse
PCC monitoring situation
PCC
ongoing
6 – Copnor Road
(Amberley Road area)
Hilsea
Flooding to main A288 Copnor Road,
rendering impassable
7
4
Good
Copnor Road Scheme – new piped network
and pumping station
Southern
Water
completed
7 – Quartremaine
Industrial Estate
n/a
High flood risk as a large part of northern
Portsea Island drains through the area
0
4
Sparse
Quartremaine Road Scheme – changes to
infrastructure and new box culvert
Southern
Water
completed
8 – Great Salterns golf Baffins
course
Golf course regularly floods when EA main
river running through the centre of the
course bursts its banks
1
11
Good
Great Salterns Scheme – additional storm
water channel, culvert and upgrade of
existing pumping station
Southern
Water
completed
9 – Copnor Road
(Monckton Road area)
Flooding in localised topographical low
spot
36
8
Good
Kiln Road Scheme addressing the issues.
Includes a new pumping station
Southern
Water
completed
78
38
Surface water
management plan
area
Overlap
wards
3 – War department
sewer
Hilsea
4 – Anchorage Park
n/a
Residential
Total
Completion
date
Groundwater
Area
Overlap
wards
5 – Great Salterns
Baffins
6 – Anchorage Park
n/a
Low topography, likely to have high
groundwater table. Highlighted as
susceptible to groundwater emergence
due to a geological permeability boundary
Proposed measures
Project lead
Gather information relating to groundwater levels, contaminants, sewer
infiltration, sea defence integrity and ground infiltration rates, for sharing
among partner organisations, internally to PCC and property developers.
Will result in a groundwater trend report for the city of Portsmouth
Environment Agency, Southern
Water, PCC planning department,
Eastern Solent Coastal Partnership
Completion
date
2020
Copnor • Local flood risk management strategy • 45
Nelson
Nelson ward is located on the western side of Portsea Island and is
form of Stamshaw Park, the MoD rifle range and the ferry ports. The
ward includes Tipner, Whale Island and the commercial ferry port.
The developed area is largely set back from the coast to the east of
the M275 motorway. The coastline runs from the Mountbatten
Centre on Tipner Lake to Flathouse Quay which are on Portsmouth
Harbour frontage.
Flooding
Nelson ward has an extensive network of separate surface water
drainage as well as some combined drainage networks.
There have been very few historical incidents of tidal flooding to
properties which are well sheltered by the motorway embankment of
the M275.
Nelson ward has been identified for targeted groundwater
investigation along the coastal side.
There have been a number of historic surface water flood events in
small pockets across the ward. It is thought that inadequacies in the
localised sewerage system have contributed. These are presently
being addressed by Southern Water and flooding has not occurred
recently in the areas where it was previously an issue.
5m
8
Key
6o
10
PICSS flood
cell 4
Ward boundary
9
areas targeted
for groundwater
investigation
SWMP
hotspots
6p
6n
A typical localised flood event which has not occurred recently
46 • Local flood risk management strategy • Nelson
Coastal
Overlap
Sea
with other defence
wards
type(s)
Area
Tipner Lake n/a
to Rotten
Row (5m)
Rotten
Row to
Albert
Johnson
Quay (6n)
Seawalls,
revetments
n/a
Seawalls,
revetments
Residential
probability flood)
of protection falls from 10% for
Tipner as sea levels rise)
Responsible
authority
32
Frontage provides protection to some residential
properties, a school and MoD rifle range. Statutory
requirement to maintain the coastal defences to minimise
the risk of any potential contaminates entering
Portsmouth Harbour’s water body. Portsmouth Harbour is
designated SAC, SPA, Ramsar and SSSi under the
Habitats Regulations. Improvements to the coastal
defences will be necessary, if the site is redeveloped, to
manage the long term flood risk. Existing standard of
protection 10%
PCC/MoD/
Repair existing seawall and
developer
re-profile flood embankment to
secure contaminated land. If the site
is regenerated, developers will
replace and improve defences
Frontage provides protection to M275, some commercial
properties and the commercial ferryport. Existing
standard of protection 2-10%
Monitor and maintain existing
defences as required
Funding
Completion
date
Uncertain Works to
secure
contaminated
land required
by 2018
Further flood protection measures
around Tipner may occur as part of
the City Deal funding
Landowner/
PCC
Contribu- Ongoing
tions
required
Surface
Surface water
management
plan area
Overlap
wards
Residential
Commercial
10 – Stamshaw
Hilsea
116
2
Flooding to a group of houses
in the local area
Historic flood
records
Sparse
Proposed measures
Project lead
Southern Water Gruneisen Road pumping station
replacement complete
Southern
Water
Completion
date
completed
Groundwater
Groundwater
desktop study
targeted area
Overlap
wards
8 – Alexandra
Park and Tipner
Nelson
9 – Stamshaw
n/a
Proposed measures
Project lead
Highlighted as susceptible to groundwater emergence Gather information relating to groundwater
levels, contaminants, sewer infiltration, sea
defence integrity and ground infiltration rates, for
Highlighted as susceptible to groundwater emergence sharing among partner organisations, internally
to PCC and property developers. Will result in a
groundwater trend report for the city of
Portsmouth
Completion
date
2020
2020
Nelson • Local flood risk management strategy • 47
Baffins
Baffins ward is located on the eastern side of Portsea Island and is
form of the southern side of Great Salterns golf course, Milton
Common, allotments and various other green spaces. The developed
area is largely set back from the coast to the west of the Eastern Road.
The coastline runs from the Harvester to Milton Common on Langstone
Harbour frontage. The ward also includes Great Salterns Lake which
acts as the main surface water drainage outlet for approximately one
quarter of Portsea Island. The lake and its tributary culvert feeding into
it from the golf course to the north are designated as a main river. It
has pumps which trigger at a certain water level in times of high tide.
Flooding
Baffins ward has a number of separate surface water drainage
networks but is largely served by combined drainage networks.
Baffins ward forms part of two separate areas identified for targeted
There are a few pockets of surface water flooding recorded, and there
have been incidents of wave overtopping along the Eastern Road
frontage which causes disruption to one of the arterial roads of
Portsmouth. It is highly likely that there was groundwater influence
on one of the more recent events.
4j
Key
8
PICSS flood cell 4
areas targeted for
Ward boundary
SWMP hotspots
5
4i
4
3h
48 • Local flood risk management strategy • Baffins
Wave overtopping along Eastern Road frontage in January 2015
Coastal
Overlap
Sea defence
with other
type(s)
wards
Area
Residential
probability flood)
Milton Bund to
Tangier Road
seawall (4i)
n/a
Seawalls,
revetments,
embankments
Frontage protects to residential properties
and Milton Common (former landfill site).
Existing standard of protection 0.5%)
Eastern Road
bridge to Great
Salterns Quay (4j)
Copnor
Seawalls,
revetments
Frontage protects to A2030, golf course,
housing estate and some commercial
properties. Existing standard of protection
0.5%.
23
of protection 0.5%)
Responsible
authority
PCC
Flood
Defence
Grant in Aid
PCC
standard of protection accounting for
sea level rise
Flood
Defence
Grant in Aid
Funding
Completion
date
Phased
from
2015/16 to
2025/26
Surface
Surface water
management
plan area
Overlap
wards
Residential
Commercial
Historic
flood
records
8 – Great
Salterns golf
course
n/a
Golf course regularly floods when EA main river
running through the centre of the course bursts its
banks
1
11
Southern Water have identified a scheme to remove
surface water from the combined sewer network
n/a
n/a
1
11
Tangier Road n/a
(not in SWMP)
Total
Completion
date
Proposed measures
Project lead
Good
Additional storm water channel, additional
culvert and upgrade of existing pumping
station
Southern
Water
completed
Some
New piped network and outfall to Great
Salterns Lake
Southern
Water
completed
Groundwater
Groundwater
desktop study
targeted area
Overlap
wards
5 – Great
Salterns
Copnor
4 – Milton
Milton
Stanley Avenue
n/a
Flooding to garages along the rear access road.
Investigations have found that the likely source is
groundwater with 95% surety.
Completion
date
Proposed measures
Project lead
Gather information relating to
groundwater levels, contaminants, sewer
infiltration, sea defence integrity and
ground infiltration rates, for sharing
among partner organisations, internally
to PCC and property developers. Will
result in a groundwater trend report for
the city of Portsmouth
end 2014
end 2014
Burehole installed to monitor GW levels
PCC with support from Souther Water
Investigations
2020
Baffins • Local flood risk management strategy • 49
Fratton
Fratton ward is located in the centre of Portsea Island and has no
coastline. There are open spaces in the form of Kingston Cemetery,
various parks and school playing fields. The developed area is
predominantly residential with a few commercial districts.
A large proportion of the ward has impermeable areas, meaning most
of the rainfall falls on hard ground (roads, tarmac, paving, roofs) and
runs along the surface until it can find a way into the sewers.
Flooding
Fratton ward has a predominantly combined drainage network.
There are a few pockets of surface water flooding recorded, but these
are very localised and are most likely caused by blocked gullies or pipes.
There is limited tidal or groundwater influence, the ward is highly
dependant on the sewerage network.
Fratton ward has not been identified for targeted groundwater
investigation.
9
Key
Ward boundary
5
A localised highway flood, typical of Fratton ward.
50 • Local flood risk management strategy • Fratton
areas targeted for
Surface
Surface water
management
plan area
Overlap
wards
Residential
none
n/a
0
Fratton ward has not been identified for surface
water investigation
Proposed measures
Project lead
Commercial
Historic
flood
records
Completion
date
0
Sparse
none at present
n/a
n/a
If you would like to report a flood:
There are a number of processes in place by which you can report a flood, or issues with the drainage system like blocked gullies:
• To report an issue with gullies anywhere in the city complete the
form by visiting www.portsmouth.gov.uk and search for
‘report it gullies’. You will need to supply an accurate address to
allow us to find the gully and short description of the problem.
• Direct to the council’s Drainage Team at drainage.team@
portsmouthcc.gov.uk or phone 023 9284 1588 which will be
picked up by a PCC Drainage Officer.
• If you believe a flood contains wastewater, PCC advises that you
contact Southern Water directly, by filling out an enquiry form at
www.southernwater.co.uk and search for ‘wastewater
enquiries’ or phone 0845 278 0845. PCC does not have the
power to work on sewers or structures owned by third parties or
other Risk Management Authorities, but we do work together to
resolve issues.
• PCC City Help Desk 023 9283 4092.
• Colas 023 9231 0900. Many local issues, where appropriate, are
passed to Colas by PCC to investigate under the terms of the
Private Finance Initiative (PFI) agreement, which is in place until
2029. In normal circumstances reported issues are investigated
and actioned within 28 days but in reality it is highly likely to be
much quicker. You may wish to call them directly.
• For social housing, we recommend you contact your area housing
office in the first instance. Visit www.portsmouth.gov.uk and
search for area housing office.
• IN AN EMERGENCY, CALL 999 IF YOU ARE IN DANGER OR
PEOPLE HAVE BEEN INJURED.
Fratton • Local flood risk management strategy • 51
Charles Dickens
Charles Dickens ward is located on the western side of Portsea Island
and includes the main shopping area of Commercial Road, HM Naval
Base and the Historic Dockyard. There are limited open spaces
although it does include Victoria Park and The Hard.
The developed area is largely set back from the coast due to the
location of HM Naval Base. The coastline runs from Flathouse Quay to
The Hard which are on Portsmouth Harbour frontage.
Flooding
Charles Dickens ward has a predominantly combined drainage network
although there are a number of surface water and private sewers.
The area is susceptible to tidal and groundwater influences to
flooding during a rain event.
Charles Dickens ward forms part of an area targeted for groundwater
investigation.
9
6p
6n
7q
11
Key
PICSS flood cell 6
PICSS flood cell 7
areas targeted for
Ward boundary
SWMP hotspots
1
1a
52 • Local flood risk management strategy • Charles Dickens
Anglesea Road affected by surface water flooding
Coastal
Overlap
Sea defence
with other
type(s)
wards
Area
Flathouse
Quay to
The Hard
(7q)
n/a
Seawalls,
revetments
Residential
probability flood)
Frontage provides protection to HM 0
Naval Base, some commercial and
residential properties. Existing
standard of protection generally
0.5%
Responsible
authority
Repair or replace seawalls as
required to a higher level to keep
pace with sea level rise
MoD/PCC
Completion
date
Funding
Alternative sources of funding
may be required to secure the
money required to implement
these works, including from the
MoD
post 2021
Surface
Surface water
management
plan area
Overlap
wards
Residential
Commercial
Historic
flood
records
11 –
Ordnance
Row
n/a
30
18
Sparse
Flooding to a cluster of properties
Proposed measures
Project lead
Southern Water sewer works have reduced
the frequency of flooding
Southern
Water
Completion
date
Completed
Groundwater
Groundwater
desktop study
targeted area
Overlap
wards
1 – City Centre
St Thomas
boundary
Proposed measures
Project lead
Gather information relating to groundwater
sharing among partner organisations, internally
Portsmouth
Completion
date
2020
Charles Dickens • Local flood risk management strategy • 53
Milton
Milton ward is located on the eastern side of Portsea Island and is
form of Bransbury Park, St Mary’s and St James hospitals, Fratton Park
football ground, allotments and various other green spaces.
The developed area is largely set back from the coast. The coastline
runs from Milton Common to the western edge of Eastney Lake on
Langstone Harbour frontage.
Flooding
Milton ward has a combination of combined, surface water and
private drainage networks.
There are sparse records of tidal flooding. There is potential for
groundwater and tidal water to influence flooding.
Milton ward forms part of two areas targeted for groundwater
investigation.
actions are outlined on the next page. An options appraisal for the
coastline is to commence in summer 2014.
Key
4i
4
PICSS flood cell 3
PICSS flood cell 4
areas targeted for
Ward boundary
SWMP hotspots
2g
3
2e
The seawall and frontage at the Thatched House
54 • Local flood risk management strategy • Milton
Coastal
Area
Overlap
Sea defence
with other
type(s)
wards
Residential
probability flood)
Responsible
authority
Funding
Completion date
Milton Bund to
Tangier Road
seawall (4i)
n/a
Seawalls,
revetments,
embankments
Frontage provides protection to residential 23
properties and Milton Common (former
landfill site). Existing standard of protection
0.5%)
PCC
Flood
Defence
Grant in Aid
Phased from
2015/16 to
2025/26
Eastney Lake to
Thatched House
PH seawall (3h)
n/a
Seawalls
Frontage provides protection to residential
and commercial properties. Existing
standard of protection 0.5%
Maintain and monitor defences
Landowner/
PCC
Landowner
2021/22
Surface
Surface water
management
plan area
Overlap
wards
Residential
none
n/a
0
Milton ward has not been identified for surface
water investigation
Proposed measures
Project lead
Commercial
Historic
flood
records
Completion
date
0
Sparse
none at present
n/a
n/a
Groundwater
Groundwater
Overlap with
desktop study
other wards
targeted area
3 – Eastney
Eastney and
Craneswater
4 – Milton
Baffins
Proposed measures
Project lead
Highlighted as susceptible to groundwater emergence Gather information relating to groundwater
Highlighted as susceptible to groundwater emergence sharing among partner organisations, internally
Portsmouth
Completion
date
2020
2020
Milton • Local flood risk management strategy • 55
St Thomas
St Thomas ward is located on the southwestern side of Portsea
Island and includes Gunwharf Quays shopping development. There
are limited open spaces although it does include part of Southsea
Common, HMS Temeraire naval sports facility and Ravelin Park.
Residential developed areas are largely set back from the coast
except in the Old Portsmouth area.
The coastline runs from The Hard to Clarence Pier which are on
Portsmouth Harbour’s entrance and the Solent.
St Thomas ward has a good surface water network with some
combined sewers. There are a few pockets of surface water flooding
recorded, but these are very localised and are most likely caused by
blocked gullies or pipes.
There are good records of coastal flooding to properties, especially in
the Old Portsmouth area.
There is a high likelihood of groundwater levels influencing flooding.
Old Portsmouth was, until recently, known to have significant
seawater infiltration to the trunk sewers. Southern Water have now
undertaken renovation of the sewer network to minimise the amount
of seawater infiltration. St Thomas ward forms part of an area
targeted for groundwater investigation.
Old Portsmouth has a network of over 30 tidal flood floodgates which
raise the standard of protection to 0.5% AEP (in 2006). The Eastern
Solent Coastal Partnership is responsible for overseeing the operation
and maintenance of the gates during high tide windows. A response is
triggered by a messaging service from the Environment Agency.
11
1
12
13
1a
Flooding
Key
PICSS flood
cell 1
PICSS flood
cell 7
Ward boundary
1b
2
areas targeted
for groundwater
investigation
SWMP
hotspots
56 • Local flood risk management strategy • St Thomas
Old Portsmouth floodgates during a high tide flood event
Coastal
Overlap
Sea defence
with other
type(s)
wards
Area
Spur
Redoubt to
Blue Reef
Aquarium
(1b)
St Jude
n/a
Old
Portsmouth
(1a)
Seawall,
revetments,
groynes,
other
residential and commercial properties
and scheduled ancient monuments.
Existing standard of protection varies
between 10-100%
Seawalls,
revetments,
other
residential and commercial properties
and scheduled ancient monuments.
Existing standard of protection 0.5%
Residential
probability flood)
533
Proposed measures (target standard of protection
0.5%)
Responsible
authority
Raise seawalls where possible along landward edge
of promenade, strengthen foreshore in areas that
rapidly lose beach material during storms and result
in damage to promenade (Clarence Esplanade
additional rock toe protection). Final set of measures
employed will be consistent with Seafront
Masterplan
Phase 1
2020/21
No works planned – defences recently improved
PCC
Phase 2
2025/26
Funding
Completion
date
Flood
Defence
Grant in
Aid
2018/19
n/a
To be
identified
by review
Strategy review for Old Portsmouth currently being
undertaken
Surface
Surface water
management
plan area
Overlap
wards
Residential
Commercial
Historic
flood
records
12 –
Hambrook
Street
n/a
9
2
Sparse
Flooding to a cluster of properties in 2009
Proposed measures
Project lead
Completion
date
PCC is monitoring the situation. There may
be a spring in the area which contributes
PCC
ongoing
Groundwater
Groundwater
desktop study
targeted area
Overlap
wards
1 – City Centre
Charles
Dickens
boundary
Proposed measures
Project lead
Portsmouth
Completion
date
2020
St Thomas • Local flood risk management strategy • 57
Central Southsea
Central Southsea ward is located in the central southern area of
Portsea Island and has no coastline. There are very limited open
spaces. The developed area is predominantly residential with a few
shopping districts.
A large proportion of the district has impermeable areas, meaning
most of the rainfall falls on hard ground and runs along the surface
until it can find a way into the sewers.
Flooding
Central Southsea ward has a predominantly combined sewer network.
There is limited tidal or groundwater influence, the ward is highly
dependant on the sewerage network.
Central Southsea ward has not been targeted for groundwater
investigation.
Key
areas targeted for
1
Ward boundary
SWMP hotspots
2
An example of the type of surface water flood in Central Southsea ward
58 • Local flood risk management strategy • Central Southsea
Surface
Surface water
management
plan area
Overlap
wards
Residential
none
n/a
0
Central Southsea ward has not been identified for
surface water investigation
Proposed measures
Project lead
Commercial
Historic
flood
records
Completion
date
0
Sparse
none at present
n/a
n/a
There are a number of processes in place by which you can report a flood, or issues with the drainage system like blocked gullies:
• To report an issue with gullies anywhere in the city complete the
form by visiting www.portsmouth.gov.uk and search for
‘report it gullies’. You will need to supply an accurate address to
allow us to find the gully and short description of the problem.
• If you believe a flood contains wastewater, PCC advises that you
contact Southern Water directly, by filling out an enquiry form at
www.southernwater.co.uk and search for ‘wastewater
enquiries’ or phone 0845 278 0845. PCC does not have the
power to work on sewers or structures owned by third parties or
other Risk Management Authorities, but we do work together to
resolve issues.
• Colas 023 9231 0900. Many local issues, where appropriate, are
passed to Colas by PCC to investigate under the terms of the
Private Finance Initiative (PFI) agreement, which is in place until
2029. In normal circumstances reported issues are investigated
and actioned within 28 days but in reality it is highly likely to be
much quicker. You may wish to call them directly.
• For social housing, we recommend you contact your area housing
office in the first instance. Visit www.portsmouth.gov.uk and
search for area housing office.
Central Southsea • Local flood risk management strategy • 59
St Jude
St Jude ward is located on the south coast of Portsea Island and
includes highly residential areas and some commercial districts and
ancient monuments. There are some open spaces including Southsea
Common and Clarendon Gardens.
Residential developed areas are largely set back from the coast. The
coastline of St Jude runs from Clarence Pier to Burgoyne Road and is
directly facing onto the Solent. The Seafront Masterplan outlines
proposals to improve the amenity value of the promenade.
Flooding
St Jude ward has a largely combined sewer network.
The ward was badly affected in 2000 by flooding, which is well
documented. It is likely that the low topography of the Great Morass
and Little Morass areas was a factor. Other factors include
groundwater, tide-locking and sewerage network issues.
There are sparse records of coastal flooding.
St Jude ward forms part of a large area targeted for groundwater
investigation.
1
Key
13
PICSS flood cell 1
areas targeted for
Ward boundary
SWMP hotspots
2
14
1b
1c
60 • Local flood risk management strategy • St Jude
Submerged cars during the September 2000 flood event
Coastal
Residential properties
presently at risk
(0.5% annual
probability flood)
Overlap with
other wards
Sea defence
type(s)
1b – Spur
Redoubt to
Blue Reef
Aquarium
St Thomas
Seawall,
revetments,
groynes,
other
Southsea Common, residential
and commercial areas and
scheduled ancient monuments
1c – Blue
Reef
Aquarium to
Southsea
Esplanade
Eastney and
Craneswater
Seawalls,
revetments,
other
amenities and residential
properties
Area
3310
Residual Life of
existing defences
Proposed measures (target standard of
protection 0.5%)
Responsible
authority
Completion
date
10-15 years except
5-10 years (Clarence
Esplanade and
Clarence Pier)
Reduce tidal flood risk from (existing) 5%
AEP to 0.5% AEP by improving coastal
defences. Construct new wave return and
splash walls, demountable defences
PCC
Phase 1
2020/21
10-15 years
Reduce tidal flood risk from (existing) 5%
AEP to 0.5% AEP by improving coastal
defences. Proposed option(s): Construct a
new wall landward of the promenade
(1.2km). Hold The Line - maintain (450m)
PCC
Phase 2
2025/26
Surface
Residential
Commercial
Historic
flood
records
13 – Pier
Road (Little
Morass)
n/a
Flooding of Southsea Common, a
topographical low point. Localised
carriageway flooding occurs regularly
4
2
Good
It is thought the local sewer network is part of the
issue. PCC is monitoring
14 –
Southsea
Eastney and
Craneswater
The area is flagged as having high surface
water flood risk due to its low topography
and combined drainage system. This is the
first point of manhole surcharge if the
Eastney pumping station were to fail
163
36
Very
good
Southern
Southern Water surface water separation schemes
Water
across Portsmouth will significantly reduce the flows
arriving at Eastney pumping station during a rain event.
This will raise the standard of protection for the area.
Both PCC and Southern Water have undertaken
property level flood protection measures in the area
167
38
Surface water
management
plan area
Overlap with
other wards
Total
Proposed measures
Project
lead
Completion
date
PCC /
Southern
Water
ongoing
completed
Groundwater
Groundwater
desktop study
targeted area
2 – Southsea
Overlap with
other wards
Eastney and
Craneswater
Proposed measures
Project lead
boundary
Portsmouth
Completion
date
2020
Eastney and Craneswater • Local flood risk management strategy • 61
Eastney and Craneswater
Eastney and Craneswater ward is located on the southeastern corner
of Portsea Island. There are large open spaces in the form of Canoe
Lake, Highland Road Cemetery, the seafront, Fort Cumberland and
some sports and recreational facilities.
The developed area is largely set back from the coast and is largely
residential. The coastline runs from South Parade Pier to the western
edge of Eastney Lake on The Solent and Langstone Harbour entrance.
The Seafront Masterplan outlines proposals to improve the amenity
value of the promenade.
Flooding
Eastney and Craneswater ward has some separate surface water and
some combined sewer networks. The ward includes Eastney pumping
station and associated rising mains, outfalls and holding tanks, which
are critical to the drainage of Portsmouth.
There are sparse records of coastal flooding, although some wave
overtopping has occurred in the past.
Tidal
4i influence on the drainage network is particularly significant in
this ward. Eastney and Craneswater ward forms part of two targeted
areas for groundwater investigation.
This area features in the Portsea Island
Coastal Strategy Study – actions are outlined
on the next page.
3h
Key
PICSS flood cell 1
2g
3
2f
PICSS flood cell 2
Ward boundary
areas targeted for groundwater
investigation
SWMP hotspots
2
2e
14
1d
1c
62 • Local flood risk management strategy • Eastney and Craneswater
Pier Road rock armour and frontage
Coastal
Overlap
Sea defence
with other
type(s)
wards
Area
Residential
probability flood)
1872
Responsible
authority
New flood wall on landward
side of promenade
PCC
Flood
Defence
Grant in Aid
Funding
Blue Reef Aquarium to
St Jude
Southsea Esplanade (1c)
Seawall,
revetments, other
Southsea Esplanade (1d)
n/a
Seawalls
Frontage provides protection to amenities
and residential properties. Existing standard
of protection varies between 0.5-100%
Melville Road caravan
site to Fraser Battery
(2e)
n/a
Seawalls,
revetments,
groynes,
embankments
Frontage provides protection to amenities
and residential properties and some
critical infrastructure. Existing standard of
protection 100% at Fraser Battery
Raise and strengthen existing
defences
Landowner/
developer
Landowner/
developer
Eastney Outfall to
Langstone Channel (2f)
n/a
Revetments,
groynes, gabions
residential properties and amenity.
Existing standard of protection 0.5%
Replace structure fronting
Eastney outfall at risk of
failure with a new revetment
and seawall
Landowner/
developer
Landowner/
developer
Langstone Channel to
Eastney Lake (2g)
n/a
Seawall, revetment,
gabions
No works in short term
n/a
n/a
Completion
date
Beyond
2025
n/a
Surface
Surface water
management
plan area
Overlap
wards
14 –
Southsea
St Jude
Residential
163
High surface water flood risk due to its
low topography and combined drainage
system. First point of manhole surcharge if
the Eastney pumping station were to fail
Commercial
36
Historic
flood
Proposed measures
records
Very
good
Project
lead
Completion
date
Southern Water surface water separation schemes will significantly
Southern by 2015
reduce the flows arriving at Eastney pumping station during a rain event Water
– raising the standard of protection for the area. PCC and Southern
Water have undertaken property level flood protection measures
Groundwater
Groundwater Overlap
desktop study with other Background information
targeted area wards
2 – Southsea St Jude
3 – Eastney
Milton
Highlighted as susceptible to
groundwater emergence due to a
geological permeability boundary
Proposed measures
Project lead
Completion
date
PCC with support requested from Environment Agency, Southern
Water, PCC planning department, Eastern Solent Coastal
Partnership
2020
Eastney and Craneswater • Local flood risk management strategy • 63
Protecting individual residential properties
23 properties in Southsea have been fitted with special equipment,
with the final property completed in February 2013. The properties
were among the worst affected by floods that hit Southsea after a
freak rainstorm in 2000.
The work was successfully undertaken after the council’s flood and
drainage team successfully won a grant from the Environment
Agency, the national body which deals with flooding.
Protection such as sealant for brickwork, special front doors, and
flood resistant airbricks was put in place. It has been designed to cope
with the kind of exceptional rainfall that has a 2% or more probability
of occurring in any given year. This can be referred to as a 1 in 50
year standard of protection.
The work package included training for residents on how to manually
deploy their flood defences in anticipation of a flood event, and ‘wet’
testing of the features once installed.
Flood doors across an internal garage, with removable central support post
A freshly installed flood door being ‘wet’ tested
64 • Local flood risk management strategy • Protecting individual residential properties
Flood insurance
The ABI and the government have recently agreed a Memorandum
of Understanding (MoU) on how to develop a not-for-profit scheme
– Flood Re – that would ensure flood insurance remains widely
affordable and available. The MoU is a first step towards establishing
Flood Re, and confirms it as the government’s preferred option.
Key elements of the framework are:
• Flood Re will be run and financed by insurers as a not-for-profit
fund which will cover the cost of flood claims from high risk
homes.
• Insurers will pass the flood risk element from those households
deemed at high risk of flooding to the fund. Premiums for the
flood risk will be calculated based on council tax banding up to a
maximum limit depending on the band.
Automatic airbricks installed
• Flood Re would charge member firms an annual charge of
£180million. This equates to a levy of £10.50 on annual household
premiums and represents the estimated level of cross-subsidy that
already exists between lower and higher flood risk premiums.
• Flood Re will be designed to fully deal with at least 99.5% of
years. Even in the worst half a percent of years, Flood Re will cover
losses up to those expected in a 1 in 200 year – a year six times
worse than 2007 – with government taking primary responsibility
– working with the industry and Flood Re – for distributing any
available resources to Flood Re policyholders should claims exceed
that level.
Providing operational issues, including governance and regulatory
approval, are resolved, the aim is for Flood Re to be up and running
by summer 2015, with regular progress reviews taking place to
ensure Flood Re can proceed. For now ABI members will voluntarily
continue to meet their commitment to continue to offer flood cover
to existing customers under the previous Flood Insurance Statement
of Principles.8
A flood door being tested for leaks during the installation phase
Flood insurance • Local flood risk management strategy • 65
Portsmouth City Council Coastal Partnership action plan
Level of
assessment
Intermediate
1a – 1d Southsea
(Harbour Railway to (Strategy)
Royal Marines
Museum)
Portsea
Island
Coastal
Strategy
Study
Current status and/or proposed mitigation of flood risk
Responsible
authority
Funding
source
Funding likelihood
Expected
completion
Reduce tidal flood risk from (existing) 5% AEP to 0.5% AEP by improving
coastal defences
Portsmouth
City Council
Capital
– FCRMGiA
Likely
Phase 1:
2012/22
Phase 2:
2025/26
2e – 2g Eastney
Spit (Royal Marines
Museum to Eastney
Lake)
Intermediate
(Strategy)
Reduce tidal flood risk from (existing) 10% AEP to 0.5% AEP by improving
coastal defences
3h Eastney Lake
Intermediate
(Strategy)
4i – 4l North
Portsea Island
(Twyford Avenue to
Milton Common)
5m Tipner (Harbour
Way to Twyford
Avenue)
Private
Uncertain
More likely
beyond 2025
Existing coastal defences provide tidal flood risk management up to 0.5% Portsmouth
AEP. Continue to monitor and maintain condition of existing sea defences. City Council
Future capital improvements to coastal defences may be necessary to keep and private
pace with sea level rise
Maintenance
– PCC
Revenue,
Improvements
– FCRMGiA
and private
Unlikely, contributions
required
2021/22
Intermediate
(Strategy)
Reduce tidal flood risk from (existing) 10% AEP to 0.5% AEP by adapting
to keep pace with sea level rise
Portsmouth
City Council
Capital – EA
FDGiA
Likely
P)hased from
2015/16 to
2025/26
Intermediate
(Strategy)
Statutory requirement to maintain the coastal defences to minimise the
risk of any potential contaminates entering Portsmouth Harbour’s water
body. Portsmouth Harbour is designated SAC, SPA, Ramsar and SSSi under
the Habitats Regulations. Improvements to the coastal defences will be
necessary, if the site is redeveloped, to manage the long term flood risk
Private
Private
Uncertain
Flood
improvements
only achievable
with
regeneration
6n – 6p Continental Intermediate
Ferry Port
(Strategy)
In order to maintain port operations the existing standard of flood risk
management (1.3% AEP) is to continue. This can be achieved by adapting
flood risk assets to keep pace with sea level rise
Portsmouth
City Council
Capital
– FCERMGiA
required
Post 2021
7q HM Naval Base
to Harbour Railway
Reduce tidal flood risk, to properties landward of HM Naval Base, from
(existing) 2% AEP to 0.5% AEP by adapting to keep pace with sea level
rise. The Ministry of Defence will continue to maintain it’s own National
Defence operations at the HM Naval Base
Portsmouth
City Council
Capital
– FCERMGiA
required
Post 2021
Intermediate
(Strategy)
Private
66 • Local flood risk management strategy • Portsmouth City Council Coastal Partnership action plan
Portsmouth City Council Coastal Partnership action plan (continued)
Portchester
to
Emsworth
Strategy
Level of
assessment
Responsible
authority
Funding
source
Funding likelihood
Expected
completion
1a – 1b Portchester
Castle to
Paulsgrove
Intermediate
(Strategy)
‘Hold The Line - Improve years 0-20 and Sustain 21-100’
PCC / FBC/
private
FDGiA and
contribution
FDGiA available to part
fund scheme cost.
Shortfall required to be
fulfilled by
contributions or cost
savings. Development
at Trafalgar Wharf
being considered
2021/22
1c Horsea Island
Intermediate
(Strategy)
All epochs ‘Hold the Line - maintain years 0-100’
Private
MoD
Uncertain
Uncertainty due
to private
ownership
M27 and Farlington
Marshes
Intermediate
(Strategy)
M27 All epochs ‘Hold The Line - Sustain years 0-100’
Private
Highways
Agency
Uncertain
Uncertainty due
to private
ownership
Intermediate
(Strategy)
Portsmouth
Farlington Marshes ‘Hold the Line – Maintain years 0-20 with a Solent
wide study to determine the long-term recommendations for the site. Hold City Council
the Line – Sustain or Managed Realignment years 21-100, based upon the
Solent wide study recommendations’. In addition to a study looking across
the context of the wider strategic network of sites, a study is required to
confirm the future management of the site. This is likely to be a range of
options from HTL to MR. This is likely to result in doing something
different, to recognise coastal change. The study will address the
economic, environmental and social implications and flood management
issues of the site. To be reflected in the implementation plan of strategy
and Action plan of the SMP. SMP, Strategy and Sustainability study are to
have clear engagement plans. The SMP and Strategy will be advising the
Regional Habitat Creation Plan of the likelihood of the need to provide
compensatory habitat for the features and amenities of Farlington
Marshes, and given the uncertain timescales this needs to be taken
account of now
Revenue –
maintenance.
Possible
capital
– realignment
Uncertain
Short term
study
completion
years 2013 to
2018. Spend
following
outcomes of
studies at latest
after 2030
Portsmouth City Council Coastal Partnership action plan • Local flood risk management strategy • 67
Portsmouth City Council drainage team action plan
PCC
drainage
team
Surface
water
management
plan
Level of
assessment
Ward(s)
Funding
source
Funding
likelihood
Expected
completion
Cosham
(north of
railway line)
Intermediate
Paulsgrove,
Cosham,
Drayton and
Farlington
This is a large area flagged due to the topography used in the model. The EA first
generation flood map AStSWF was used which doesn’t take into account drainage
systems. It also treats the railway line as a bund, which is not the case as water can
pass underneath the railway in several places through culverts. Recommended (in part)
for groundwater investigation
PCC
revenue
high
2020
Farlington
Marshes
Intermediate
Drayton and There are no properties on the marshes to flood. The sea wall surrounding the marshes
Farlington
is nearing the end of its design life which the Coastal Partnership are addressing with
the Environment Agency through a feasibility study. It has been discovered that a
surface water sewer drains into the marshes via Station Road, Sainsburys and under
the railway and A27. Investigations into the sewer function and integrity of the
network, culverts and ditches are ongoing
PCC
revenue /
Southern
Water
reactive
high
ongoing
War
department
sewer
Intermediate
Hilsea,
Copnor
A very small number of properties are effected by the low frequency flooding that
occurs along its 2km length. Exact location and function of sewer is unclear but it is
identified as a Southern Water asset. Further investigation required
Not yet
known
not
identified
ongoing
Anchorage
Park
Intermediate
Copnor
There are no significant historic flooding events recorded here. The area is flagged as
having high flood risk due to its low topography. The risk is further increased by the
estate having a combined drainage system. Any surface water separation scheme
would be very costly to implement. Recommended for groundwater investigation
PCC
revenue
not
identified
2020
Northern
Parade (Alex
Way area)
Intermediate
Hilsea
PCC are aware of the service road flooding and it has been documented numerous
times. Residents’ garages are routinely flooded but internal properties are unaffected.
Access to the sports facilities is affected but this is unadopted highway and is presently
leased to Parkwood Leisure. The surface water catchment that feeds into the Alex Way
sewer is relatively large for the pipes that currently serve it. A detailed model of the
catchment has been produced by PCC, no easy solution has been found. Southern
Water are aware of the issues and ongoing works to repair found blockages have not
resolved the situation so far
PCC
revenue /
Southern
Water
reactive
high
ongoing
68 • Local flood risk management strategy • Portsmouth City Council drainage team action plan
Portsmouth City Council drainage team action plan (continued)
Level of
assessment
Ward(s)
Detailed
Hilsea,
Copnor
Southern Water surface water scheme addressing the issues Copnor Road Scheme
completed
Quartremaine Intermediate
Industrial
Estate
Copnor
Southern Water surface water scheme addressing the issues Quartremaine Road
Scheme
completed
Great
Salterns Golf
Course
Intermediate
Copnor,
Baffins
Southern Water surface water scheme addressing the issues Great Salterns Scheme
Copnor Road
(Monckton
Road area)
Detailed
Copnor
Southern Water surface water scheme addressing the issues Kiln Road Scheme
completed
Intermediate
Nelson
Southern Water pumping station upgrade addressing the issues Gruneisen Road Scheme
completed
Intermediate
Charles
Dickens
The flooding at this location has been addressed by Southern Water through sewer
cleaning and maintenance
Hambrook
Street
Intermediate
St Thomas
We believe this was a one off incident caused by the flood of 2000. No further records
of flooding in the area exist. Southern Water undertook sewer renovations in the area
in 2007. Within area recommended for groundwater investigation
PCC
revenue
high
2020
Pier Road
(Little
Morass)
Intermediate
St Thomas,
St Jude
Pier Road is a natural flood plain which floods during heavy rainfall, no properties are
affected. Access to sea front is affected but there are numerous alternative routes.
Within area recommended for groundwater investigation
PCC
revenue
high
2020
Southsea
(Great
Morass)
Detailed
St Jude,
Eastney and
Craneswater
The Southern Water surface water separation schemes will help reduce the flows to the PCC
existing systems. The recent Blue Flag sewer renovation works carried Southern Water revenue
has improved the capacity of the current system which has further reduced the flood
risks. Within area recommended for groundwater investigation
high
2020
SuDS Approval Body
Detailed
ALL
citywide
A sub-element of planning applications which requires separate drainage submission
for new developments. High potential to reduce flood risk
Fee charged high
to developers
unknown
Groundwater Information
gathering
Desktop
study
ALL
citywide
Groundwater monitoring information in partnership with other agencies at strategic
locations
Revenue
high
2020
Highway drainage
local level
ALL
citywide
Reactive and proactive maintenance of highways drainage
PFI funded
high
2029
Copnor Road
(Amberley
Road area)
PCC
drainage
team
PCC /
Colas
Surface
water
Stamshaw
management
Ordnance
plan
Row
Funding
source
Southern
Water via
OFWAT
Funding
likelihood
Underway
Expected
completion
completed
Completed
Portsmouth City Council drainage team action plan • Local flood risk management strategy • 69
Southern Water Services action plan
Scheme / procedure
AMP5 Business
Plan 2010-2015
Level of
assessment
Primary type of
flood risk
Ward(s)
Funding
source
Kirtley Close CSO
Detailed
Drayton and New flap valves, access route and renovation to prevent tide
Farlington
locking influence
Spice Island
Detailed
St Thomas
Lining of sewers to reduce seawater infiltration and some remedial
gully rerouting
Gruneisen Road
Detailed
Nelson
Pumping station upgrade and capacity increase
OFWAT
Great Salterns
Detailed
Copnor,
Baffins
New channel and culvert to handle additional flows from schemes
to the north of the area. Pumping station upgrade
OFWAT
Tangier Road
Detailed
Baffins
OFWAT
Copnor Road
Detailed
Hilsea,
Copnor
Surface water separation. New pumping station
OFWAT
Quartremaine Road
Detailed
Copnor
Surface water separation. Upgrade Great Salterns pumping station
OFWAT
Kiln Road
Detailed
Copnor
Surface water separation. New pumping station
OFWAT
HM Naval Base
Detailed
Charles
Dickens
OFWAT
Rodney Road
Detailed
Milton
Surface water separation, may be shelved depending on flow
savings at Eastney being achieved by the above
OFWAT
Surface water
Funding
likelihood
Expected
completion
completed
completed
Awarded
completed
AMP6 Business
Plan 2015-2020
Information not yet High level
available
n/a
Information not yet available
OFWAT
high
covers period
2015-2020
AMP7 Business
Plan 2020-2025
Information not yet High level
available
n/a
Information not yet available
OFWAT
high
covers period
2020-2025
ALL
citywide
Information not yet available – To inform AMP applications
SW
Revenue
high
covers period
2015-2020
High level
ALL
citywide
Information not yet available – To inform AMP applications
SW
Revenue
high
covers period
2015-2020
n/a
ALL
citywide
Ongoing – reactive and proactive fixes to main sewers
Revenue
high
ongoing
Drainage Area Plan
Long Term Sewerage Plan
Drainage Maintenance
High level
Foul water
70 • Local flood risk management strategy • Southern Water Services action plan
Environment Agency action plan
Scheme / procedure
Level of
assessment
Primary type of flood risk
Ward(s)
Funding
source
Funding
likelihood
Expected
completion
Detailed
Fluvial and coastal
ALL citywide
EA to continue with flood warning activities and improvements
to improve resilience to flooding
EA
high
ongoing
Detailed
Coastal
Baffins,
Drayton and
Farlington
EA to continue current maintenance activities, pending future
management decisions in some locations (e.g. Farlington
Marshes)
EA
high
ongoing
Detailed
Coastal
Drayton and
Farlington
Installation of flood control structures to vehicle/cattle underpass
and culvert beneath A27 at Farlington Marshes to reduce risk of
tidal inundation
EA
high
completed
Detailed
Fluvial
Copnor,
Baffins,
Drayton and
Farlington
Permissive powers to undertake work as necessary; issue of
permits under Water Resources Act 1991 and Southern Region
Byelaws
EA
high
ongoing
Production and updating of national
flood maps
High level
Surface water, main river,
reservoir and coastal
ALL citywide
Hazard mapping for rivers and sea, and UFMfSW (Updated Flood
Map for Surface Water), both available at the end of 2013
EA
high
ongoing
Production of national flood plans,
strategies and guidance
High level
Surface water, main river,
reservoir and coastal
ALL citywide
Responsible for the delivery of national plans and strategies like
River Basin Management Plans, Catchment Flood Management
Plans, Portchester to Emsworth Flood and Coastal Erosion Risk
Management Strategy
EA
high
ongoing
Advice on flood risk to new
development
Detailed
Surface water (pending
SAB), main river, coastal,
reservoir, groundwater
ALL citywide
EA to continue to provide advice on strategic planning
documents and site specific development proposals in relation to
flood risk
EA
high
ongoing
Respond to pollution incidents
Detailed
All
ALL citywide
Reactive and proactive (e.g. bathing water quality sampling)
EA
high
ongoing
Flood Warning Service
Sea wall maintenance
Farlington Marshes culvert works
Main river management
Environment Agency action plan • Local flood risk management strategy • 71
What you can do to minimise the effects of flooding
Environment Agency advice on preparing for a flood9
Sign up to Flood Warnings Direct (see also page 60)
To register by telephone, or if you need help during the registration
process, please call Floodline on 0845 988 1188.
Flood Guidance Statement 10:30hrs 19 December 2012
Our assessment of daily flood risk for England and Wales is below.
Make a personal flood plan
Plan in advance what you will do if your property floods.
You can complete a personal flood plan online by visiting
www.environment-agency.gov.uk and search floods.
Complete a community flood plan
This is so community members and groups know how they will work
together to respond quickly when flooding happens. This advice is for
people active in the local community, leaders of community groups,
schools, hospitals or residential care homes and anyone else involved
in supporting communities to be better prepared for flooding.
Prepare a flood kit
Put together a kit of essential items you’ll need to hand if it floods.
Would you need extra support during a flood?
As part of your flood planning we recommend you think about who
you can ask for assistance before, during and after a flood. The EA
can also deliver flood warnings for your property to a relative or
friend, so that they are aware when you may need help. You can set
this up by phoning Floodline on 0845 988 1188.
10:30 - 23:59hrs
Wednesday
19 December 2012
00:00 - 23:59hrs
Thursday
20 December 2012
00:00 - 23:59hrs
Friday
21 December 2012
00:00 - 23:59hrs
Saturday
22 December 2012
00:00 - 23:59hrs
Sunday
23 December 2012
Headline
Significant river and surface water flooding likely from Wednesday evening through Thursday. This is a period of
raised flood risk generally, with further significant disruption possible over the weekend.
General Overview of Flood Risk
Successive periods of rain moving across England and Wales are falling on wet ground leading to the potential for significant
disruption across much of southern and central England and southeast Wales on Wednesday into Thursday. For southern
coastal counties and in Northamptonshire the flood risk is MEDIUM, as coloured amber on the maps above, while the flood
risk is LOW where the counties are coloured yellow.
Residual flood risks are then maintained for Friday as river response is likely to be ongoing, particularly in Northamptonshire
and along the Rivers Severn, Thames and Trent.
Further rainfall is then expected on Saturday. This is most likely to affect southwest England and parts of Wales and following
on from wet conditions on Wednesday and Thursday there remains the potential for some significant impacts here and so the
flood risk is currently LOW.
Ongoing flooding issues on the Somerset Levels and in Dorset and Wiltshire may be exacerbated by further rainfall.
The FGS will be updated this afternoon.
Warnings and Alerts in force in England and Wales at 10:30hrs
Flood (click here)
0 Severe Flood Warnings / 4 Flood Warnings / 37 Flood Alerts
Severe Weather (click here)
Alerts - Yes / Warnings - Yes
Best Judgement
Prepare your property for flooding
It’s impossible to completely flood-proof a property but there are lots
of things you can do to reduce flood damage. Some useful
information and advice on buying flood protection products is
available at www.environment-agency.gov.uk and search floods.
© Crown, Met Office and Environment Agency 2012
http://www.ffc-environment-agency.metoffice.gov.uk
An example of a Flood Guidance Statement issued by the Met Office
72 • Local flood risk management strategy • What you can do to minimise the effects of flooding
Page 1 of 3
References
1. www.solentpedia.info/our_changing_coast/coastal_squeeze
2. www.environment-agency.gov.uk/homeandleisure/37837.aspx
3. www.environment-agency.gov.uk/homeandleisure/floods/31680.aspx
4. en.wikipedia.org/wiki/Thames_barrier
5. www.gov.uk/government/news/
new-streamlined-planning-guide-launched-online
6. www.push.gov.uk
7. Environment Agency
8. www.abi.org.uk/News/News-releases/2013/06/ABI-andGovernment-agree-Memorandum-of-Understanding-on-schemeto-safeguard-UK-flood-insurance
9. Environment Agency
10.Environment Agency
There are a number of processes in place by which you can report
a flood, or issues with the drainage system like blocked gullies:
• To report an issue with gullies anywhere in the city complete
the form by visiting www.portsmouth.gov.uk and search
for ‘report it gullies’. You will need to supply an accurate
address to allow us to find the gully and short description of
the problem.
• If you believe a flood contains wastewater, PCC advises that
you contact Southern Water directly, by filling out an enquiry
form at www.southernwater.co.uk and search for
‘wastewater enquiries’ or phone 0845 278 0845. PCC does
not have the power to work on sewers or structures owned by
third parties or other Risk Management Authorities, but we do
work together to resolve issues.
• Colas 023 9231 0900. Many local issues, where appropriate,
are passed to Colas by PCC to investigate under the terms of
the Private Finance Initiative (PFI) agreement, which is in place
until 2029. In normal circumstances reported issues are
investigated and actioned within 28 days but in reality it is
highly likely to be much quicker. You may wish to call them
directly.
• For social housing, we recommend you contact your area
housing office in the first instance. Visit www.portsmouth.
gov.uk and search for area housing office.
Southsea Castle sea defences. © ‘The News’, Portsmouth
References • Local flood risk management strategy • 73
Glossary of terms
Term
The ‘Act’
AEP
Aquifer
AMP5/6
Meaning
The Flood and Water Management Act 2010.
Annual Event Probability – see SoP / Standard of Protection.
A source of groundwater comprising water bearing rock, sand or gravel capable of yielding significant quantities of water.
Asset Management Plan – A plan for managing water and sewerage company (WaSC) infrastructure and other assets in
order to deliver an agreed standard of service. AMP5 covers the period 2010-2015, AMP6 2015-2020.
BREEAM
BRE Environmental Assessment Method is the world’s foremost environmental assessment method and rating system for buildings.
CFMP
Catchment Flood Management Plan: A high-level planning strategy through which the Environment Agency works with
their key decision makers within a river catchment to identify and agree policies to secure the long-term sustainable
management of flood risk.
Climate Change Long term variations in global temperature and weather patterns caused by natural and human actions.
Combined sewer A sewer that drains both rainwater and foul water.
CSO
Combined sewer overflow. When a combined sewer reaches capacity it can overflow into another sewer (often a surface
water sewer) at strategic points to relieve pressure and reduce the risk of foul water flooding.
Culvert
A channel or pipe that carries water below the level of the ground.
Defra
Department for Environment, Food and Rural Affairs.
EA
Environment Agency.
ESCP
Eastern Solent Coastal Partnership.
FDGiA
Flood Defence Grant in Aid – Environment Agency controlled national funding stream for flood defence works.
Flood defence
Infrastructure used to protect an area against floods, such as floodwalls and embankments; they are designed to a specific
standard of protection (design standard).
Flood Risk Area An area determined as having a significant risk of flooding in accordance with guidance published by Defra and WAG.
FRR
Flood Risk Regulations 2009; Transposition of the EU Floods Directive into UK law. The EU Floods Directive is a piece of
European Community (EC) legislation to specifically address flood risk by prescribing a common framework for its
measurement and management.
HIOW
Hampshire and Isle of Wight.
HRA
Habitat Regulations Assessment.
Impermeable
A surface, geology type or structure through which water can NOT travel.
LDF
Local Development Framework.
LLFA
Lead Local Flood Authority – Local Authority responsible for taking the lead on local flood risk management.
74 • Local flood risk management strategy • Glossary of terms
Term
LRF
LPA
MoD
OFWAT
PCC
PEMS
Permeable
PFRA
PPS25
PICSS
RBMP
RFCC
Risk
RMA
SAB
SEA
SE7
SFRA
SMP
SoP / Standard
of Protection10
The ‘Strategy’
SuDS
SWMP
WFD
Meaning
Local Resilience Forum – a multi-agency forum of all the organisations that have a duty to cooperate under the Civil Contingencies
Act 2004, and those involved in responding to emergencies. They prepare emergency plans in a co-ordinated manner.
Local Planning Authority.
Ministry of Defence.
The economic regulator of the water and sewerage sectors in England and Wales.
Portsmouth City Council.
Portchester Castle to Emsworth Coastal Strategy.
A surface, geology type or structure through which water can travel.
Preliminary Flood Risk Assessment.
Planning Policy Statement 25: Development and Flood Risk.
Portsea Island Coastal Defence Strategy Study.
River Basin Management Plan – South East.
Regional Flood and Coastal Committee – Portsmouth is within the Southern RFCC region.
In flood risk management, risk is defined as a product of the probability or likelihood of a flood occurring, and the
consequence of the flood.
Risk Management Authority – specifically for Portsmouth these are the EA, LLFA, water company and the highway authority.
SuDS Approval Body.
Strategic Environmental Assessment.
South East Seven.
Strategic Flood Risk Assessment.
Shoreline Management Plan.
The standard to which an area is protected against flooding. This is generally expressed as a Annual Event Probability (AEP).
For example, an SoP of 10% means an area is protected against a flood with a 10% probability of occurring in any given
year. An SoP of 0.5% AEP means an area is protected against a flood with a 0.5% probability of occurring in any given year.
The flood with a 0.5% AEP has a lower likelihood of occurring than a flood with a 10% probability, but will be greater in
severity (higher water levels). A 0.5% AEP standard of protection is therefore higher than a 10% standard of protection.
PCC Local Flood Risk Management Strategy.
Sustainable Drainage System – Methods of management practices and control structures that are designed to drain
surface water in a more sustainable manner than some conventional techniques. For example, releasing rainwater directly
back to the environment instead of traditional piped networks.
Surface Water Management Plan.
EU Water Framework Directive.
Glossary of terms • Local flood risk management strategy • 75
Coastal and Drainage Team
Transport and Environment
Portsmouth City Council
Civic Offices
Guildhall Square
Portsmouth PO1 2NE
Telephone: 023 9284 1588
Email: [email protected]
äà
åã
You can get this Portsmouth
City Council information in large
print, Braille, audio or in another
language by calling 9284 1588.
Designed by: [email protected]
Published: March 2015 Ref: 13.2

Local flood risk management strategy

Transcription

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