North Yorkshire
Council
Transport,
Economy, Environment and Enterprise
Overview and
Scrutiny Committee
12
April 2023
Preventing
Flooding on Highways – Gully Clearance and
Maintenance
Report of the
Corporate Director - Environment
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1.0
Purpose of Report
1.1
To provide members
with an update on the progress and performance to date of NY
Highways, the Council’s company for the operational delivery
of highway services, on highway gully cleansing.
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2.0
Background
2.1
A highway delivery options exercise was undertaken in 2018/19 to
determine the mechanism for the operational delivery of highways
services. In April 2019 the Executive approved the
implementation of a wholly owned “Teckal company” to
deliver the highways operational services. A Teckal company
was recommended as the preferred way forward and, upon the approval
of the Teckal company, a 5 Year Plan was developed which contained
the following milestones:
·
2019/20 and 2020/21
Development of NY Highways (years 1 and 2)
·
2021/22 Implementation
of NY Highways (year 3)
·
2022/23 and 2023/24
Review performance of NY Highways (years 4 and 5)
2.2
NY Highways has since undertaken collaborative reviews with
colleagues on current and future ways of working that promote
innovation and efficiency throughout its services. A report was
presented to this committee on 11 July 2022, outlining a number of
achievements and performance milestones, which included but was not
limited to:
·
Seamless mobilisation
of NY Highways during Covid-19
·
Successful delivery of
the winter service
·
Delivery of the
Capital schemes programme
·
Storm Arwen
response
·
Introduced new methods
of service delivery
·
Release of 5-year
carbon plan which has been approved at NYH Board
meetings.
·
Secured Local Council
Road Improvement Group (LCRIG) Innovation funding
·
Roll-out of the
Connected Safety Net (CSN) applications for Safety and
Audit
·
Incident recording
tool (Accident book) that is GDPR compliant and track the incident
through the investigation process and closure.
2.3
Another key element of that report and of particular interest to
Members was the highway gully cleansing operation. The 11 July 2022
report outlined the roll-out of a pilot scheme for Kaarbontech
Gully solution, key points being a new risk-based approach for
gully cleaning based on previous year’s data along with
Environment Agency data to determine the number of gullies to be
attended each year. The analysis of this data will ensure
that the gully crews only need to attend gullies that require
attention, therefore saving time and costs associated with gully
maintenance. During the NYH mobilisation period, five new state of
the art gully tankers were purchased in addition to three existing
tankers that were transferred from Ringway, there were
unfortunately some reliability issues with the new gully tankers
which have now been resolved and although NYH has experienced these
difficulties during the Pandemic, and whilst the introduction /
embedment of the Kaarbontech programme was still in its infancy and
part-introduced in May 2022, NYH still managed to attend around 75%
of the programmed gullies, which is comparable with the previous
contractor’s performance.
2.4
Ultimately, programmes
of scheduled (and non-scheduled) gully cleansing contribute towards
the policy objectives contained in the over-arching Highway Asset
Management Plan. The relevant extract from this plan is included as
Appendix A to this report.
2.5
More recent
developments:
During the course of
the last year, surveys have been completed in Area 1 (Richmond),
Area 3 (Whitby), Area 6 (Harrogate) and Area 7 (Selby) to define
their programmes of work; this was due to historic data being not
sufficiently reliable. However, Area 2 (Hambleton), Area 4
(Ryedale) and Area 5 (Craven) have had programmes derived from
existing data, which was sense-checked to ensure its robustness and
confirm no need for additional surveys.
2.6
Current
position:
2022/23 has
essentially been a transition year with regard to fully deploying
the new risk-based approach. Our surveys show that there are
164,171 gullies on the highway network. This risk-based programme
approach identifies that 98,503 gullies need to be attended in any
given year, with some higher-risk locations requiring more than one
clean in that twelve month period (taking the total number of
attendances to 106,711). This represents some 65% of the total
attendances required. That 65% is targeted and constantly-updated
by performance data that directs where those cleanses are required.
Conversely, the previous cleansing regime (built up over a number
of years on a combination of limited data and local knowledge) was
much less-reliable and included inefficiency, with some locations
being attended only to find that the gully pot was silt-free and
water in the pipework running freely.
Data collected and
sense-checked indicates that by the end of February 2023, the total
number of gullies attended was 77,252 in 2022/23. Good progress
through March, which was less-impacted by adverse weather and
included some weekend / longer-day working, means that completion
of the full 98,503 programme is expected on 14 April 2023. This
represents 92.3% performance, and a further improvement on the 75%
figure reported for last year.
2.7
Forward look /
planning & programme:
By April 2024, all
parts of the county will have had at least twelve months of the new
Kaarbontech risk-based regime and therefore any inefficiency in
attending gullies under the old regime/programme that would have
been part of the 22/23 year (i.e. prior to transitioning to the
risk-based programme) will be removed so those gullies that do not
need attending are removed through the ‘living’
Kaarbontech programme. The Kaarbontech programme can also be
updated to ensure non-scheduled attendances are not duplicated with
a scheduled attendance a week later.
3.0
Conclusion
3.1
Ultimately, the core objective as outlined in the policy extract
below is removing water from the highway network. This in turn
improves safety for those travelling within and through the county
and reduces risk of accidents, particularly during winter where ice
is an additional hazard. Taking this risk-based approach
and using empirical data, which is continually evolved, means that
resource is deployed where needed as opposed to travelling to a
site and finding the gully is free of silt / detritus and
free-flowing. Fully embedding the Kaarbontech programme in 2023/24
alongside the performance improvement that has been achieved in
2022/23 is commended to members to note.
5.0
Financial Implications
5.1
There are no financial implications arising directly from this
report as it provides an update on progress.
6.0
Legal Implications
6.1
There are no legal implications arising directly from this report
as it provides an update on progress.
7.0
Equalities
Implications
7.1
An initial equalities impact assessment form was completed and is
included as Appendix B. The assessment of this report concluded
that there is no impact on people with protected
characteristics.
8.0
Environmental Impacts/Benefits including Climate Change Impact
Assessment:
8.1
See Appendix C. This risk-based 5-year Carbon Plan positively
contributes towards the reduction in carbon used when delivering
the highways services.
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9.0
Recommendation
9.1
Committee Members are requested to note the information within the
report and offer comments or suggestions where
necessary.
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Appendices:
Appendix A –
Highways Drainage System information / policy taken from Generic
NYCC Highways Asset Management Plan
Appendix B – Initial
equality impact assessment screening form
Appendix C –
Climate Change
Assessment
Background
Documents:
Report to TEE O&S
Committee 11 July 2022
KARL
BATTERSBY
Corporate Director,
Environment
County Hall
Northallerton
24 March
2023
Report Author and
Presenter: Nigel Smith, Interim Head of Operations NY Highways /
Head of Highway Operations NYC
Note: Members are invited to
contact the author in advance of the meeting with any detailed
queries or questions.
Highways Drainage
System information / policy taken from Generic NYCC Highways Asset
Management Plan
Highways drainage
systems
The condition of
highway drainage systems can contribute to the core objectives as
follows:
·
Safety - accumulation
of water on carriageways, footways and cycleways
·
Serviceability -
accumulation of water on carriageways, footways and
cycleways
·
Sustainability -
polluted effluent from clearing of highway drainage affecting
watercourses
o
Inadequate drainage of
the highway structure will reduce effective life and increase
maintenance liability.
o
Authorities have a
duty to prevent nuisance to adjoining landowners by flooding and
should also work with others in the wider community to minimise the
future risk of flooding.
Highway drainage
systems fall into the main headings of:
·
culverts
·
grips and
ditches
·
piped
drainage
·
pumps.
Under these headings
there are two distinct categories of drainage system maintenance
and drainage cleaning/cleansing.
Drainage system
maintenance comprises:
·
maintenance and
replacement of existing carriageway drainage systems
·
replacement and
realignment of kerbs for drainage purposes
·
maintenance and
replacement of culverts and structures up to a diameter of 1.5m or
a span of 1.5m (culverts and structures exceeding these
measurements fall within the scope of the bridges team and their
associated Highways Structures Asset Management Plan)
·
all drainage works not
included in reconstruction, overlay, resurfacing or surface
dressing
·
maintenance to pumps
and sumps is carried out by specialist contractors.
The objectives of
drainage system maintenance are to maintain the structural
integrity of existing drainage systems to prevent accumulations of
water on the carriageway, to prevent the ingress of water into the
pavement structure and to maintain the highway in a safe condition
for road users and pedestrians.
The Highway Gully
Cleansing policy describes the cyclical maintenance of the gulley
infrastructure throughout the county. The risk based approach
mirrors the safety, serviceability and sustainability core
objectives. The policy recognises the need for a reactive service
to exist to assist in the management of highways drainage however
mandates that this is a part of a whole process feeding back into
the cyclical maintenance.
Any reactive
maintenance is decided on a needs based approach assessed by the
regular inspection of the highway, local knowledge and reports from
the public.
In regard to safety,
types of defects to be recorded and investigatory levels are
included in the Highways Safety Inspection Manual. Culverts under
roads and manholes should be inspected for structural damage or
deterioration and cleaned when required. Piped drainage, soakaways
and associated systems should be checked and flushed during service
inspections and cleared when required.
Where a drainage
system exists, it should be capable of removing water from the
carriageway as it reaches a gully or grip. Where this is not the
case and cleaning or jetting does not affect an improvement, the
necessary remedial action should be taken as soon as
possible.
For ironware
comprising covers, gratings, frames and boxes set in carriageways
the following condition standards apply. Manhole covers and boxes
should be installed to a tolerance of +/- 5mm to the surrounding
level. Gully frames and gratings should be installed level or not
exceeding 10mm lower than the surrounding carriageway. When boxes,
frames and covers are found to be greater than 20mm lower than the
surrounding carriageway they should be re-set.
Drainage
cleaning/cleansing comprises:
The testing, rodding
and jetting of the highway drainage system. This includes drains,
gullies, piped ditches, grips, carriageway drainage on structures
and drainage of subways. The cleaning of drainage installed outside
the highway boundary under licence or easement should be
included.
The cleaning of
gullies and catchpits or manholes which are the responsibility of
the highway authority. As a guide, this is all surface water
drainage the sole purpose of which is to remove water from the
highway; however, this is not always the case. If in addition the
drainage system carries roof water or water from private
properties, that system is the responsibility of other authorities.
In these cases, the highway authority is responsible for the gully
and gully connections only.
The maintenance of
ditches and grips through the removal of silt, vegetation growth
and damage to allow free passage of water from the highway. The
maintenance should be confined to those ditches which are the
responsibility of the highway authority (in the main, ditches are
the responsibility of the adjoining landowner). Section 100 of the
Highway Act 1980 empowers authorities to keep open ditches on land
adjoining the highway.
The objectives of
drainage cleaning/cleansing are to prevent water penetrating the
foundations of carriageways and footways, to remove detritus from
gullies or catchpits to ensure the rapid removal of water from the
road surface, to maintain free flow conditions in all open channels
and grips and to maintain self-cleansing flows in the drainage
pipes, catchpits and outfalls.
The policy is to carry
out the required amount of drainage cleansing and cleaning
commensurate with the objectives and needs. They are assessed
through routine highway inspections, awareness of frequent flooding
at a particular location, reports of drainage defects from gully
maintenance operatives and complaints of malfunction. Types of
defects to be recorded and investigatory levels are included in the
Highways Safety Inspection Manual.
Grip clearing should
be commenced after the last grass cut of the year and completed if
possible before the onset of winter. Kerb offlets can sometimes be
neglected and should be jetted as necessary to ensure efficient
working.
Areas at risk of
flooding should be identified and recorded within the Highway Asset
Management System. Inspection of these sites will form part of the
safety inspection regime. Supplementary checks should be undertaken
during periods of heavy rainfall as resources allow.
Gullies are cleansed
according to their associated schedule, which is based on the age
of the gully, the location. Non-functioning or damaged gullies are
recorded by the contractor and reported to the client for further
investigation and remedy.
Priority is given to
inspecting and cleansing sections of system which pose a high risk
of flooding or disruption to the network. During all drainage
investigation records of the system must be compiled and added to
the inventory.
Gullies should be over
filled when emptied to ensure that they are clear. If not, the unit
should be recorded for jetting. No more than 50mm of material
should remain in the unit before it is recharged with clean
water.
The frequency of
cleansing of oil interceptors will depend on their design and
location and will need particular consideration on a site specific
basis. Material arising from all road drainage emptying and
cleansing operations has potential implications for pollution and
should be disposed of correctly in accordance with the Environment
Agency requirements.
