Hillingdon Council Cabinet Member and Officer Decisions
Ruislip Lido On-site Flood Plan - PART II
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Ruislip Lido
On-site Plan
February 2022
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022
Ruislip Lido
On-site Plan
February 2022
Revision 2
Commissioned (and revised) by:
London Borough of Hillingdon
Civic Centre, Uxbridge
Middlesex UB8
Prepared by:
Binnies UK
60 High Street
Redhill
Surrey
RH1 1SH
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
September 2021 (i)
CONTENTS
1. OBJECTIVES, SCOPE AND ADMINISTRATION OF THE PLAN 1
1.1 Objectives .................................................................................................................. 1
1.2 Scope ......................................................................................................................... 1
1.3 Administration of the plan.......................................................................................... 1
2. MANAGEMENT OF EMERGENCY BY UNDERTAKER 4
2.1 Undertaker’s procedures and authorised personnel .................................................... 4
2.2 External communications ........................................................................................... 7
2.3 Checklist for those attending emergency .................................................................... 7
3. DESCRIPTION OF THE RESERVOIR AND RETAINING DAM 8
3.1 Situation ..................................................................................................................... 8
3.2 Detailed records ......................................................................................................... 8
3.3 Physical dimensions and features ............................................................................... 9
3.4 Other features relevant to on-site operations .............................................................. 9
3.5 Access to reservoir ..................................................................................................... 9
3.6 Communications at reservoir ................................................................................... 11
3.7 Welfare facilities ...................................................................................................... 11
3.8 Normal Operation .................................................................................................... 11
4. ACTIONS BY UNDERTAKER ON SITE 12
4.1 Situation assessment ................................................................................................ 12
4.2 Undertaker’s Resources relevant to on-site activities ............................................... 12
4.3 Reservoir drawdown ................................................................................................ 12
4.4 Other measures ........................................................................................................ 14
4.5 Off-site impacts of site activities .............................................................................. 14
5. MAINTENANCE OF THE PLAN 15
5.1 Training of staff ....................................................................................................... 15
5.2 Periodic testing of equipment ................................................................................... 15
5.3 Exercising of On-site Plan........................................................................................ 15
5.4 Review and updating plan ........................................................................................ 16
ATTACHMENT A: MAPS SHOWING ACCESS TO DAM SITE 17
ATTACHMENT B: HYDROMETRIC DATA AND ESTIMATED INFLOWS 21
ATTACHMENT C: RESERVOIR LEVEL AGAINST ELEVATION AND DRAWDOWN
CAPACITY 24
ATTACHMENT D: VALVE ARRANGEMENT 25
ATTACHMENT E: INFORMATION SUPPLEMENTARY TO RESERVOIR RECORD 26
ATTACHMENT F: INFORMATION TO BE UPDATED FREQUENTLY 27
ATTACHMENT G: MAINTENANCE LOG 30
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
September 2021 (ii)
Change log for plan:
Rev Date Details of nature of
change
By Ckd Approved Accepted
by EA Owner Panel Eng
1
24
August
2021
Draft HR JH
2 Feb
2022 Updated for Certification HR JH PS-K
Management Information
Person responsible for preparing the plan On behalf of Pam Siva-Kumar, LBH
01895 250441
psiva-kumar@hillingdon.gov.uk
Name of Engineer certifying the plan John Hopkins, Binnies UK
Date of plan TBC
Who to contact about the plan Pam Siva-Kumar, LBH
01895 250441
psiva-kumar@hillingdon.gov.uk
Date for plan to be reviewed February 2023
Date(s) for testing the plan Before February 2027
How the plan will be tested Seminar/incident simulation exercise
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
September 2021 1
1. OBJECTIVES, SCOPE AND ADMINISTRATION OF THE PLAN
1.1 Objectives
This plan forms part of the risk management of Ruislip Lido, comprising the measures that
would be taken on site in the event of a serious problem with the structural stability of the
dam. It also satisfies the requirements for Element II of a Flood Plan under Section 12A of
the Reservoirs Act 1975 (added through Section 77 of the Water Act 2003).
1.2 Scope
This plan covers Ruislip Lido, owned by the Londo n Borough of Hillingdon (LBH) who
are also the Undertaker.
The principal characterist ics of the reservoir are summarised in Table 1 and are shown in
the figures in Appendix A.
Table 1: Details of Ruisip Lido
Capacity at spillway crest 400,000 m3
Location & National Grid
Reference
Reservoir Road, Ruislip. TQ 088 890
Consequence Class A1
Frequency of surveillance visits Weekly visits by LBH
Personnel with a knowledge of the dam’s behaviour
Undertaker’s staff See Table 2
Other Supervising Engineer (John Hopkins)
1. Shown on Ordnance Survey Landranger (1:50,000 scale) sheet 176 and Explo rer (1:25,000
scale) sheet 172
1.3 Administration of the plan
The status of this document is as shown in the document h istory record, and it is issued to
those shown in Table 2. It has been pre pared by Binnies UK and with input from the
London Borough of Hillingdon.
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On-site Plan
Binnies February 2022 2
Table 2: Distribution list for copies of this document and personnel who would be involved in managing any emergency on site
Position Name Postal Address
Phone
Office Out of hours Mobile
Internal – London Borough of Hillingdon
Reservoir Safety Manager
(Structures and Watercourses Manager)
Pam Siva-Kumar London Borough of
Hillingdon
2E/05 Civic Centr e,
High Street
Uxbridge UB8 1UW
psiva-kumar@hillingdon.gov.uk
Tel: 01895 250441
Emergency Planning Officer Pam Siva-Kumar London Borough of
Hillingdon
2E/05 Civic Centre,
High Street
Uxbridge UB8 1UW
psiva-kumar@hillingdon.gov.uk
Tel: 01895 250441
Interim Head of Highways Poonam Pathak London Borough of
Hillingdon
2E/05 Civic Centre,
High Street
Uxbridge UB8 1UW
ppathak@hillingdon.gov.uk
Tel: 01895 277557
Network Operations Manager Wayne Greenshields London Borough of
Hillingdon
2E/05 Civic Centre,
High Street
Uxbridge UB8 1UW
wgreenshield@hillingdon.gov.uk
Tel: 01895 250564
Reactive Maintenance Supervisor Martin Kenealy Harlington Road Depot
128 Harlington Rd,
Uxbridge UB8 3EY
mkenealy@hillingdon.gov.uk
Tel: 01895 277552
Rapid Response Officer Rapid
Response/Standby
Flood Officer (Rota
basis)
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On-site Plan
Binnies February 2022 3
Borough Emergency Control Centre
Manager
London Borough of
Hillingdon
Emergency Response Officer London Borough of
Hillingdon
Borough Emergency Control Centre
Manager
London Borough of
Hillingdon
Emergency Response Officer London Borough of
Hillingdon
Supervising Engineer
John Hopkins
Binnies UK
60 High Street Redhill
RH1 1SH
Reservoir Inspecting Engineer (Last S10)
(Now retired)
John Ackers
Alternative AR Panel Engineer Dominic Molyneux
Rachel Pether
Enforcement Authority – Environment Agency
a) Technical Manager - Reservoir Safety Environment Agency
Reservoir Safety
Manley House
Kestrel Way
Sowton Industrial
Estate
Exeter EX2 7LQ
-
b) Regional Office - Operations Manager
(EA switchboard)
-
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On-site Plan
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February 2022 4
2. MANAGEMENT OF EMERGENCY BY UNDERTAKER
2.1 Undertaker’s procedures and authorised personnel
London Borough of Hillingdon’ Emergency Procedures apply. This includes:
• Standard company procedures for managing emergencies;
• Lists of staff positions authorised to take action and manage the emergency;
• Contact lists for individuals filling each position; and
• Escalation sequence for incident, related to severity.
• Strategic multi-agency Reservoir Plan
London Borough of Hillingdon employ a Supervising Engineer (John Hopkins) supplied
by Binnies UK, who visits the reservoir twice a year. Binnies UK has other All Reservoir
Panel Engineers whose contact details are given in Appendix F. An All Reservoirs Panel
Engineer will be appointed by London Borough of Hillingdon in an emergency to come to
site and supervise the situation.
Any incident would be escalated as shown in Table 3. The responsibility for implementing
each stage and where appropriate escalating to the next stage lies with the London
Borough of Hillingdon staff listed in Table 2. Initially re sponsibility would be with the
first of these to visit the site; passing to the Reservoir Safety Manager when they arrive on
site.
Table 3: Stages in escalation of incident management
Stage Title Activity
1 Preliminary assessment London Borough of Hillingdon representative visits site,
determines whether a serious incident
2 Situation assessment a) A panel engineer (normally the Supervising Engineer)
visits site
b) Declare serious incident
c) Set up incident control centre
d) Panel AR Engineer appointed and comes to site.
3 On-site measures Initiate on-site measures
4 External notification Notify Local Authority Emergency Planning Officers of
serious structural problem with dam
5 Off Site Plan If at any moment there is a potential for a dam breach the
immediate actions of the off site plan must be activated.
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On-site Plan
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February 2022 5
Table 4: On-Site Action and Trigger Levels
Stage Status Details of Trigger(s) Undertaker’s Actions Local
Responders
Actions
STANDBY
(dam breach
possible)
ALERT Earthquake/landslip
affects local area.
Movement in dam crest /
slope / toe observed.
Uncontrolled release of
water, spillways blocked,
downstream culvert
blocked.
Exceptional rainfall event,
either forecast or
occurring.
Advice from Supervising /
Inspecting Engineer.
LBH contact Supervising
and/or Inspecting Engineer
and arrange immediate visit,
if required.
LBH acting controller to be
kept informed of the
situation.
LBH acting
controller may
contact all
relevant partners
to place on
standby.
Increase
frequency of
readings and
surveillance.
ADVISORY A structural problem in the
dam has been detected or
reported to the
undertaker(s).
A precautionary
drawdown is to be carried
out to reduce the
likelihood of failure to an
acceptable level.
Undertaker(s) to contact
LBH Structures.
Organise
emergency
drawdown
pumps.
Arrange for road
closure.
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On-site Plan
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February 2022 6
Table 5: Off-Site Action and Trigger Levels
Stage Status Details of Trigger(s) Undertaker’s Actions Local
Responders
Actions
IMPLEMEN
TATION
(dam breach
imminent –
dam has
failed))
ALARM An emergency drawdown
is required to avert failure
of dam structure.
LBH attends scene and
provides updates to local
responders and Supervising /
Inspecting Engineer.
Acting
Controller
activates and
implements Off-
site Plan in
conjunction with
partners and
undertakes all
necessary
mitigating
actions.
Acting
Controller
implements all
relevant multi-
agency
command and
control
arrangements, in
accordance with
the ERF Multi
Agency
Reservoir Plan,
with
participation of
Duty Officer
and relevant
engineers.
IMMINENT
FAILURE
Control of the reservoir
has been lost and failure
is inevitable.
FAILED The dam has failed and
large uncontrolled release
of water has occurred.
STAND-
DOWN
(flood waters
subsided or
return to
properties
permitted)
POST-
STANDBY
Serious problem averted None ‘All clear
given’.
Review plan in
light of response
and any ensuing
recommendation
s.
POST
IMPLEMENT
ATION
Water flows from the
reservoir are minimal and
efforts are focussed on
consequences in zones of
devastation.
None Focus on on-
going response
and recovery
operations
affecting the
needs of local
populations,
buildings,
critical
infrastructure
etc.
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On-site Plan
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February 2022 7
Table 6: On-Site Roles and Responsibilities
Role Typically Undertaken By Responsibilities Include
Duty Officer Structures and Watercourse Manager
Highways Manager
Delivery Manager
Out of Hours Call Out Engineer
Will attend site in an emergency and implement
emergency procedures as necessary, managing
other Council emergency on site staff.
Will liaise with Acting Controller as required
Acting
Controller
Lead Emergency Planning and
Resilience Consultant
No actual on-site role but will manage any
emergency remotely, liaising between Council Duty
Officer, Council on-site emergency staff, the
Environment Agency and emergency services as
necessary.
Major problems and incidents will be reported to
the Supervising Engineer who will liaise with the
Inspecting Engineer if necessary.
The London Borough of Hillingdon Borough Emergency Control Room (BECC) would be
managed by the Incident Controller. They will be responsible for
a) Contacting the designated appropriate personnel to provide the frontline team;
b) Facilitating implementation of on-site measures; and
c) Any other actions requested.
London Borough of Hillingdon communications manager will be desi gnated as the Press
Officer at the sta rt of the incide nt. All questions posed by the media shall be directe d to
this Press Officer. No -one else from London Borough of Hillingdon , or the Supervising /
Inspecting Engineer, shall pro vide inf ormation direct to the media unless spe cifically
requested to by the Press Officer.
2.2 External communications
External notification of an i ncident will be made once it has reached Advisory level, or
greater, as defined in Table 4.4 of the draft Engineering Guide to Emergency Planning for
UK Rese rvoirs (released by Defra in June 2006). This will b e the Du ty Manager , after
Director level authorisation. Notification will be to the Local Resilience Forum and use the
form in Element III of the Flood Plan. Where a Director is not a vailable then the Dut y
Manager shall issue the external notification, to avoid any delay in off-site actions.
2.3 Checklist for those attending emergency
The individual in charge at the dam site should arrange to take, or to have delivered to site,
the informa tion listed in Table 7. Clearly the pr iority should be to get to the dam and
arrange for any missing items to be delivered to site from elsewhere.
Table 7: Checklist of information and ancillary equipment required on site
Available from
1 Mobile phone (and charger) Use personal
2 Copy of this plan Hard c opy – files in London Borough of H illingdon office
control room, also copy held by supervising engineer 3 Copy of drawings/reservoir records
4 Confined space equipment Not required to operate control valves
5 Food & water Emergency Management Command Structure to organise out
of hours
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On-site Plan
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February 2022 8
3. DESCRIPTION OF THE RESERVOIR AND RETAINING DAM
3.1 Situation
Ruislip Lido was constructed in about 1810 as a feeder for the Grand Union Canal. It is now used
primarily as an amenity and for recreation. It also functions as a flood control facil ity and, for this
purpose, the water level has since the early 1990’s been kept to about 0.65m to 1m below the sill
level of the auxiliary spillway.
The reservoir is retained by an earth embankment dam. It is circa 6.7m high, 200m long with a
surface are a of 14 4,000 m2 and a capacity of approx. 300,000m3. The reservoir has a maximum
depth of about 6m and a top water area of 144,000m2. The reservoir is operated to provide flood
alleviation. Water level is normally managed to a target retention level of 49.5m OD. This is 1m
below top water level. The reservoir is very rarely fu ll or nearly full. The embankment has a crest
length of 59m and a m aximum height of 4.4m. The reservoir draw off occurs through a valve
controlled pipe di scharging into a culvert through the downstream half of the dam, where flow is
released downstream into the Cannon Brook and carried south toward the River Pinn.
The reservoir has been de signated ‘High Risk’ and is considered Category A in accordance wi th
Floods and Reservoir Safety, 4th Ed, ICE, 2015.
Figure 1 - Ruislip Lido – Location Plan
3.2 Detailed records
All data is held electronically on the company computer system, in addition to this there is a hard
copy of this report held in the reservoir fil e in head office with the Operational Statistics section .
The various databases are summarised in Table 8.
Copies of the information is also available on the Binnies compu ter system and h ard copies in the
files.
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February 2022 9
Table 8: Location of information on reservoir
Information Electronic Database Other
LBH Network Other
Drawings Highways Shared Drive Hard copies in
Highways cabinet
Last Inspection report Highways Shared Drive
Supervising Engineers
statements
Monitoring data
Prescribed form of record
Drawdown Assessment
Report
3.3 Physical dimensions and features
This plan summarises the key dimen sions and other information which would be of value
to have to hand in an emergency, as follows
Table 6: Key dimensions of the dam
Date built (Original construction) 1810
Dam crest level 52.2 mAOD
Wave wall (main) 53.09 mAOD
Wave wall (central overtopping section) 52.49 mAOD
Height of dam crest above downstream toe 7 m
Dam crest length 200 m
Dam crest width 4 m
Main Spillway 1.85m dia. shaft to 1.2m dia, culvert
Auxiliary Spillway 0.6m pipe discharging into shaft of main
spillway
m
Main Spillway sill level 50.48 mAOD
Auxiliary Spillway sill level 49.76 mAOD
Freeboard (at TWL) 2.34m
Upstream slope 1 in 5.5 above 0.6m high wall and 1 in 6.5
below
Downstream slope 1 in 3.5 above and below berm
Type Homogeneous earthfill embankment,
assumed to have been built from sandy
gravelly clay
3.4 Other features relevant to on-site operations
None
3.5 Access to reservoir
Access to the dam from the nearest public road is via the A4180 onto Reservoir Road.
From there the dam crest can be accessed either by car or on foot although vehicle access
is restricted by a locked barrier.
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February 2022 10
Table 7: Access to elements of dam
Issue Access
Public access The Lido is a public recreation area with a beach.
Members of the public are able to access the dam crest
and the water along the full length of the crest.
Undertaker’s personnel Good access from road across the berm. Through
access along the crest road is restricted by bollards.
Access for works
Upstream Face The upper part of the upstream face is grassed with a
well-maintained turf and a gentle enough slope for
pedestrians
Downstream face The downstream face is predominantly grassed with a
tarmac road on a berm, and is easily accessed on foot
(public access)
Crest The crest has a concrete wave wall on the upstream
side, which for much of its length acts as an emergency
weir, with a tarmac road covering the majority of the
crest. The road will have to be closed off if any works
are to be undertaken.
Drawoff pipe The outlet enters the shaft through a single 18” pipe
from the reservoir and immediately bifurcates. There
are then three valves in line on each branch of the pipe
before they discharge into a culvert running
downstream to the toe of the dam.
Overflow There is a concrete approach to the drawoff pipe with
its control being the upstream end of the concrete slab.
These are easily accessed by staff
Auxiliary spillway The auxiliary spillway including grille is easily
accessed and inspected
Main spillway The main spillway is covered by a concrete bridge
deck. Access is via a personnel access gate in the grille
(keys and access to be obtained from undertakers).
Staff would need to be confined space trained to access
the spillway shaft and culvert.
Drop shaft A vertical drop shaft discharges the water from the
main spillway into the downstream culvert. This can be
visually inspected from the top but it not accessible
without specialised abseiling equipment.
Downstream culvert The culvert can be accessed by qualified personnel with
confined space training. A removable grille, in good
condition, normally covers the outlet.
Downstream toe By foot from the road across the berm on the
downstream face of the dam.
Access for operation of valves The outlet enters the shaft through a single 18” pipe
from the reservoir and immediately bifurcates. There
are then three valves in line on each branch of the pipe
before they discharge into a culvert running
downstream to the toe of the dam. The valve shaft can
be accessed via the valve house outlet structure which
has a metal access ladder. Maintenance staff normally
periodically operate (monthly) the downstream
London Borough of Hillingdon Ruislip Lido
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February 2022 11
butterfly control valves.
The main control valves are either operated from the
valve house at the crest of the dam or remotely. There
is CCTV installed to check the status of the control
valves.
The guard valves are operated from the base of the
shaft. They are normally kept open and only
occasionally test operated.
Main outlet culvert Access into the upstream end is from the valve shaft; ladder
access. The downstream end of the culvert is more difficult
to access, requiring removal of the grille. The culvert also
bends so it is not possible to view much of it from the
downstream end. A fixed grille covers the downstream end.
3.6 Communications at reservoir
Mobile phone coverage at the dam site is considered good and reliable:
3.7 Welfare facilities
The nearest public toilets can be found adjacent to the Water’s Edge Pub and Restaurant,
and by Ruislip Lido beach. Out of hours access organised by BECC Manager.
3.8 Normal Operation
During normal operation, Ruislip Lido delivers protection against downstream flooding by
functioning as fl ood storage. Outflow from the spillway channel is normally conveyed
through a culvert underneath the dam cres t ro ad and the adjacen t Park Wood, where it
discharges into Cannon Brook and is conveyed further downstream to the River Pinn.
The various functions relevant to operation o f the reservoir in an emergency are liste d in
the distribution lis t for this docume nt, shown in Table 2. London Borough of Hillin gdon
regularly schedule surveillance visits (minimum of weekly) to Ruislip Lido.
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4. ACTIONS BY UNDERTAKER ON SITE
4.1 Situation assessment
In the eve nt of a proble m, London Borough of Hillin gdon would contact the Supervising
Engineer for advice, which if a serious incident was in progress would lead to the
appointment of an All Reservoirs Panel Engineer.
The first step on arrival of an engineer at the dam is assessment of the situation, to assess:
• Likely mode of failure and estimated time to failure if no action were taken;
• Candidate options for actions that could be taken to delay or avert failure;
• Availability of resources, both on site and at short notice from off-site; and
• Risk assessment of candid ate options, in terms of likely effectiveness in av erting
failure, health and safety issues for personnel on site and environmental impacts.
The checklist in Table 4 .8 of the Engineering Guide for Emergency Planning for UK
Reservoirs may be used to assist this process. The action(s) to be taken will be det ermined
by the Site Lead.
4.2 Undertaker’s Resources relevant to on-site activities
4.2.1 Equipment at dam site
N/A
4.2.2 Resources which could be brought to site
It has been identified that the Environment Agency and the Fire and Rescue Service have
equipment that could assist in breach mitigation actions, i.e. High Volume pump and other
pumping equipment.
London Borough of Hillingdon ha ve the following equipment available or approved
suppliers for pump hire (available at short notice):
Contractor/Supplier Skills/Equipment Contact Name Contact Number
O’Hara Br os (Term
Contractor)
Pumps
O’Hara Bros (Term
Contractor)
Pumps
4.3 Reservoir drawdown
4.3.1 Capacity of permanent installations
Drawdown is via a single 460mm (18 inch) pipe from the reservoir w hich bifurcates into
two 230mm (9 inch ) pipes. There are three inline valves on each branch; two g ate valves
and one butterfly valve.
The theore tical installed drawdown c apacity at TWL is circa 0.5 m 3/s. This gives a n
installed drawdown rate of 6.52%H/da y, equ ivalent to 287mm/day. It would take
approximately 4.2 days to empty the top third of the reservoir. The pres ent actual
drawdown capacity, based on a flow test carried out in 2018 after the upstream grille was
London Borough of Hillingdon Ruislip Lido
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February 2022 13
replaced, is circa 0. 3 m3/s. At 0. 3 m3/s this gives a drawdown rate of 3.24%H/day
equivalent to 144mm/day. The basic rec ommended drawdown fo r a Category A dam is
5%H/day equivalent to 220mm. The theoretica l i nstalled capacity meets this standa rd.
However, the present actual capacity does not.
Attachment C includes data on the reservoir volume.
4.3.2 Operation of permanent installation
The two main control valv es are either operated from the valve house at the crest of the
dam or remotely.
The guard valves are normally kept open.
4.3.3 Provision for installing and operating pumps
The reservoir drawdown could be supplemented with pumps brou ght to the s ite. It would be
practical to install up to about 0.5m3/s of temporary pumping capacity but it is unclear how long it
would take for this to be installed. There is good access across the dam and suitable locations for
pump installations. (See Attachment A, Map 3) The discharge would either be into the overflow
channel on the downstream left flan k or the outlet ch annel downstream of the centre of the d am.
However, there is currently no special provision for the installation of additional pumps.
Pump Location Estimated suction hose
length
Estimated delivery hose
length
Crest of dam by spillway 30m 40m
Crest of dam near valve house 40m 40m
Note: The pump hoses are likely to pass across the access road on the b erm which will need
special provision for traffic to pass over.
The Environment Agency and the Fire and Rescue Ser vice have equipmen t which c an assist in
breach mitigation actions, i.e High Volume Pump and other pumping equipment. Further
investigation should be undertaken and contacts established in the Fire and Rescue service. There
is good access across the dam and suita ble locations for p ump installations. The discharge would
either be into the overfl ow channel on the downstream left flank or th e outlet channel downstream
of the centre of the dam. Advice should be sought on how long it would take to source and install
this additional capacity. See Attachment A, Map 3 for loading and unloading area.
These data are used to provide illustrations of required pumping capacity to reduce the load on the
dam by half (lower to 66% water depth), as follows:
Theoretical Present With
temporary
pumps
Rate of lowering mm/day 287 144
Reservoir capacity in top 33% m3 150,000 – 200,000
Days to lower to T33% (50% of
volume)
days 4.2 7.3 2.5
Inflow volume in winter m3/s 0.02
Total volume to be evacuated by
pumps
m3 - -
Pumping rate m3/s - - 0.5
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4.4 Other measures
The checklists in Appendix C of t he Engineering Guide to Emergency Plann ing for UK
Reservoirs would be used in the event of an emergency.
4.5 Off-site impacts of site activities
During normal operation, Ruislip Lido delivers protection against downstream flooding by
functioning as flood storage. However, according to the 2016 emergency plan, up to 5,200
members of the public would be at risk in the event of overtopping during a storm event,
or in the event of a breach during site activities.
Outflow from the spillway channel is normally conveyed through a culvert underneath the
dam crest road and the adjacent Park Wood, where it discharges into Cannon Brook and is
conveyed further downstream to the River Pinn.
Figure 2 shows t he Environment Agency’s Flood Map. This in dicates that areas of
flooding (I in 100 year flood), that risk flooding properties, could occur on Cannon Br ook
in the vicinity of the A4180 and Ladygate Road, however the Halcrow Flood Risk
Assessment Report, dated September 2011, found that the flooding risk at the A4180 is
overstated.
Figure 2 – Environment Agency Flood Map
(Extract from Halcrow, Flood Risk Assessment Report, dated September 2011)
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February 2022 15
5. MAINTENANCE OF THE PLAN
5.1 Training of staff
The members of London Borough of Hillingdon staff listed in Table 2 each hold and have
read a co py of the Engineering Guide to Emergency Planning for UK Reservoirs . The
panel engineers at Binnies UK are kept up to date in respect of confined spaces and CDM
Regulations training courses.
A seminar/incident simulation exercise should be held at the frequency shown in Table 8,
to test and discuss the arrangements, confirm their practicality and identify improvements
that could be made t o incr ease the value of the plan and/or reduce costs. It should be
attended by the London Borough of Hillingdon staff listed in Table 2 and the Superv ising
Engineer.
In addition, at le ast one of the staff listed in Table 2 should attend a site visit with th e
Supervising Engi neer to che ck the pra cticality of i mplementation of the on-site
arrangements set out in this Plan.
5.2 Periodic testing of equipment
a) The gate valves should be test operated at least once per year. (Test operations
should be included in the Prescribed Form of Record.)
b) The actuated draw-off valves are normally tested monthly. The actuated valves
are o perated reg ularly to control the reservo ir wate r level. These have been
modified and n ow allow on and off-site operation . A CCTV system allows
visual moni toring of v alve positions. The gate va lves are not r outinely
operated, but should be test operated at le ast once per year, as per a) . [In the
event of a power cut it is unlikely to be possible to operate the control valves.]
5.3 Exercising of On-site Plan
Exercising shall be carried out as shown in Table 8.
Table 8: Frequency of exercising of on-site plan for Ruislip Lido
Item in plan to be
checked
Method of testing Frequency of testing Responsibility for
testing (sign off on test
sheet)
24 hour contact number
for pump supplier
Phone numbers at
2300hrs
Annually Reservoir safety
manager
Undertaker’s 24 hour
emergency response
Phone designated number
at 2300hrs
Annually Reservoir safety
manager
Contact of London
Borough of Hillingdon
staff listed in Table 2 and
Attachment F
Check details correct Annually Reservoir safety
manager
In-house seminar / incident
simulation exercise
See Section 5.1 One every 5 years Reservoir safety
manager
Contact equipment and
material suppliers to
confirm their availability
during an emergency
Included in seminar.
Phone numbers
Once every 5 years
Site attendance including
operation of valves.
Check practicality of
on-site arrangements
Once every 5 years Reservoir safety
manager
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022 16
5.4 Review and updating plan
The list of contacts in Attachment F should be checked annually, with a checklist of dates
and times phone numbers were checke d given in t he format in Attachment F. 3 and
included in the Supervising Engineer’s annual statements.
This plan sh ould be reviewed (and updated or modified as a ppropriate) at the frequency
shown in Table 8:
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022 17
ATTACHMENT A: MAPS SHOWING ACCESS TO DAM SITE
Map 1: Regional access to Ruisip Lido
o
This map is shows the local access routes and roads. The site is directly accessible via the A4180/Duck’s Hill Road onto
Reservoir Road.
Regional access from the major motorways is as follows:
• From the A 40 by exiting onto the B467/B reakspear Rd S heading North towards
Ruislip; Alternatively you can take the B466.
• From the A25 by taking any exit towards Ric kmansworth, followed by the
A404/London Road and onto the A4180 /Duck’s Hill Road.
The nearest train stations to Ruislip Lido are:
West Ruislip (1.7 mi)
Ruislip Manor (1.5 mi)
Ruislip (1.5 mi)
Northwood Hills (1.7 mi)
Eastcote (2.2 mi)
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022 18
Map 2: Local access routes and constraints
Access to the dam from the nearest public road is via the A4180 onto Reservoir Roa d. From there
the dam crest can be accessed either by car or on foot although vehicle access i s restricted by a
locked barrier.
The nearest public toilets can be found adjacent to the Water’s Edge Pub and Restaurant, and by
Ruislip Lido beach.
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022 19
Map 3: Temporary Pump Locations
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022 20
Map 4: Extent of Maximum Flood Outline (Reservoir Inundation)
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022 22
Grid Reference: TQ083846
Operator: EA
Local number: 3620TH
Catchment Area: 17.6km2
Level of Station: 32mOD
Max. Altitude: 113.40mOD
Mean flow: 0.13m3s-1
95% exceedance (Q95): 0.008m3s-1
10% exceedance (Q10): 0.314m3s-1
61-90 Av. Ann. Rainfall: 657mm
Sample Hydrograph of Gauged Daily Flows
Flow Duration Curve for Gauged Daily Flows
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022 23
Station Description
Gauging station located on Yeading Brook West, a sma ll tributary of the River Crane. The st ation
was closed in 1995.
Catchment Description
Impervious, suburban catchment in NW London, including some of the runoff from Northolt
Airport. Some agricultural land immediately u/s of the station..
Factors Affecting Runoff
N/A
River Flow and Catchment Rainfall on the National River Flow Archive
Gauged Daily Flows (gdf): 1979 to 1994
Catchment Daily Rainfall (cdr): 1961 to 2017
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022 24
ATTACHMENT C: RESERVOIR LEVEL AGAINST ELEVATION AND DRAWDOWN
CAPACITY
Figure C.1: Reservoir volume
RUISIP LIDO CAPACITY VS DEPTH
Water Level
(mAOD)
Amount of
drawdown (m)
Volume of water
in storage (m3)
Remarks
50.5 0 400,000 Main Overflow Level
50.0 0.5 320,000
49.5 1.0 250,000 Normal retention level/Target Level
49.0 1.5 200,000
48.5 2.0 160,000
48.0 2.5 125,000
47.5 3.0 90,000
47.0 3.5 60,000
46.5 4.0 30,000
46.1 4.4 0.00
45.67 - - Drawoff pipe IL
Note: Storage on this chart is calculated from the main overflow level (50.48mAOD). The official Top
Water Level is considered the weir sill in front of the auxiliary spillway pipe (49.76mAOD)
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022 25
ATTACHMENT D: VALVE ARRANGEMENT
Photograph showing arrangement of valves. Remotely controlled butterfly control valves are
those furthest downstream (top of photo)
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022 26
ATTACHMENT E: INFORMATION SUPPLEMENTARY TO RESERVOIR RECORD
None
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK
February 2022 27
ATTACHMENT F: INFORMATION TO BE UPDATED FREQUENTLY
Details of checks/updates since last major revision of plan
Date Updated by Comments
F.1 Pump suppliers
Pump suppliers Phone Distance from site
Working hours Out of hours
Environment Agency
F.2 Panel AR Engineers
Name Office address Phone
(working
hours)
Out of hours (24
hour contact)
Mobile
Binnies UK
60 High Street
Redhill,
RH1 1SH
Dominic
Molyneux
Rachel Pether
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK Ltd
February 2022 28
F.3 London Borough of Hillingdon staff who would be called upon first in an emergency
Name Office address Skills,
equipment
Phone and email
Work Out of hours Mobile
Pam Siva-Kumar London Borough of Hillingdon
Civic Centre, Uxbridge,
Middlesex UB8 1UW
Engineering
Structures
Manager
psiva-kumar@hillingdon.gov.uk
01895 250441
Poonam Pathak London Borough of Hillingdon
Civic Centre, Uxbridge,
Middlesex UB8 1UW
Interim Head of
Highways
ppathak@hillingdon.gov.uk
01895277557
Wayne
Greenshields
London Borough of Hillingdon
Civic Centre, Uxbridge,
Middlesex UB8 1UW
Network
Operations
wgreenshield@hillingdon.gov.uk
01895250564
Martin Kenealy Harlington Road Depot, 128
Harlington Road, Uxbridge UB8
3EY
Reactive
Maintenance
Supervisor
mkenealy@hinningdon.gov.uk
01895277552
-
Rapid Response/
Standby Flood
Officer (Rota)
London Borough of Hillingdon Borough
Emergency
Control Centre
Manager
London Borough of Hillingdon Emergency
Response
Manager
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK Ltd
February 2022 29
F.4 Schedule of associated documents to be read with this plan
Type Title Plan Latest Revision Remarks
Originator Owned by Rev No Date Custodian/contact
Emergency
response
Ruislip Lido
Reservoir
Emergency Plan
London Borough
of Hillingdon
London Borough of
Hillingdon
Draft May
2016
Emergency
Drawdown
Ruislip Lido -
Drawdown
Assessment
Black & Veatch London Borough of
Hillingdon
1 May
2018
London Borough of Hillingdon Ruislip Lido
On-site Plan
Binnies UK Ltd
February 2022 30
ATTACHMENT G: MAINTENANCE LOG
G.1 Exercising since On-site Plan issued
Details of entry Details of exercise Details of debriefing/lessons learnt Actions taken/ remarks
Date Name Date Level Lead
Individual
Date Lead
individual
Location of
report
G.2 Contact verification and callout simulation
Details of
entry
Details of verification Result of call Any Actions taken/ remarks
Date Name Date Time Type Lead individual
RUISLIP LIDO
Reservoirs Act 1975
Certificate under section 12AA(3), as to the requirements of a
direction under section 12A(2)(a) and (b) being satisfied
I John Hopkins of Binnies UK Ltd, 60 High Street, Redhill, Surrey. RH1 1SH, being a
member of the Supervising Panel, appointed by London Borough of Hillingdon to
consult on the preparation of a flood plan under section 12A for the reservoir known
as Ruislip Lido situated at Reservoir Road, Ruislip, Middlesex NGR: TQ 088 890, am
satisfied that the requirements of a direction under section 12A(2)(a) and (b) are
satisfied.
3 February 2022
RUISLIP LIDO
Reservoirs Act 1975
Direction under section 12AA(4) by Appointed Engineer, as to the
testing of a flood plan
I John Hopkins of Binnies UK Ltd., 60 High Street, Redhill, Surrey. RH1 1SH, being a
member of the Supervising Panel appointed by London Borough of Hillingdon to
consult on the preparation of a flood plan under section 12A for the reservoir known
as Ruislip Lido situated at Reservoir Road, Ruislip, Middlesex NGR: Reservoir
Road, Ruislip. TQ 088 890, direct that the flood plan be tested as specified below,
the interval commencing on 3 February 2022. A report of the test shall be provided
to assess the need for revision of the plan.
Element of flood plan
Manner of testing
Interval between tests
24 hour contact number for pump
supplier
Phone numbers at 2300hrs Annually
Undertaker’s 24 hour emergency
response
Phone designated number
at 2300hrs
Annually
Contact of London Borough of
Hillingdon staff listed in Table 2
and Attachment F of Plan
Check details correct Annually
In-house seminar / incident
simulation exercise
See Section 5.1 of Plan One every 5 years
Contact equipment and material
suppliers to confirm their
availability during an emergency
Included in seminar. Phone
numbers
Once every 5 years
Site attendance including
operation of valves.
Check practicality of on-site
arrangements
Once every 5 years
3 February 2022
View Decision / Minutes Text
Executive Decision Notice – 01 August 2022 Page 1 This notice is a public document also available to view on the Council's website www.hillingdon.gov.uk OFFICIAL EXECUTIVE DECISION NOTICE PUBLISHED BY DEMOCRATIC SERVICES Notice is hereby given that the following decision(s) have been made today by Cabinet Members at the London Borough of Hillingdon: Title of decision Ruislip Lido On-site Flood Plan Reference No. 541 Date of decision Monday 01 August 2022 Call-in expiry date 5pm, Monday 08 August 2022 Relevant Select Committee Property, Highways and Transport Select Committee Relevant Ward All Decision made Cabinet Members making the decision Councillor Jonathan Bianco – Cabinet Member for Property, Highways and Transport Approved That the Cabinet Member for Property, Highways and Transport approves the Ruislip Lido On-site Flood Plan for adoption by the Council as required under sections 12A (1) and (2) of the Reservoir Act, in conjunction with the Corporate / Executive Director. Reason for decision Under sections 12A (1) and (2) of the Reservoir Act, the London Borough of Hillingdon is required to prepare a flood plan for the Ruislip Lido in response to The Secretary of State's directive in 2021 to prepare a flood plan in relation to large, raised reservoirs. As there is no Cabinet meeting in late July or August 2022, the plan has been prepared for compliance and submitted for Cabinet Member approval. Alternative options considered and rejected As it is a legal requirement for large, raised reservoirs, such as Ruislip Lido, to have an approved onsite flood plan , no alternative options were copsidered. Classification Part I - Public Link to associated report Report Relevant Officer contact & Directorate Pam Siva-Kumar, Highways Executive Decision Notice – 01 August 2022 Page 2 This notice is a public document also available to view on the Council's website www.hillingdon.gov.uk Any interest declared by the Cabinet Member(s) / dispensation granted N/A Implementation of decision & scrutiny call-in [Internal Use only] When can this decision be implemented by officers? Officers can implement Cabinet Member decision in this notice only from the expiry of the scrutiny call-in period which is: 5pm, Monday 08 August 2022 However, this is subject to the decision not being called in by Councillors on the relevant Select Committee. Upon receipt of a valid call-in request, Democratic Services will immediately advise the relevant officer(s) and the decision must then be put on hold. Councillor scrutiny call-in of this decision Councillors on the relevant Select Committee shown in this notice may request to call-in this decision. The request must be before the expiry of the scrutiny call-in period above. Councillors should use the Scrutiny Call-in App (link below) on their devices to initiate any call-in request. Further advice can be sought from Democratic Services if required: Scrutiny Call-In - Power Apps (secure) Further information These decisions, where applicable, have been taken under The Local Authorities (Executive Arrangements) (Meetings and Access to Information) (England) Regulations 2012. This is the formal notice by the Council of the above executive decision, including links to the reports where applicable. If you would like more information on this decision, please contact Democratic Services on 01895 250636 or email: democratic@hillingdon.gov.uk. Circulation of this decision notice is to a variety of people including Members of the Council, Corporate Directors, Officers, Group Secretariats and the Public. Copies are also placed on the Council’s website. Democratic Services London Borough of Hillingdon Civic Centre High Street Uxbridge UB8 1UW Executive Decision Notice – 01 August 2022 Page 3 This notice is a public document also available to view on the Council's website www.hillingdon.gov.uk