Scrutiny of Hertfordshire
County Council’s Land
The Land Drainage Topic Group
For further information please contact:
Head of Scrutiny
Hertfordshire County Council
Tel: 01992 555300
1. Background X
3. Summary of evidence X
Interagency working, including
discharge of duties
HCC (strategic, limitations)
EA (statutory obligations, limitations)
HCC Drainage Action Plan
Interim Pitt Report
4. Conclusion X
5. Glossary of terms and abbreviations X
Appendix 1 – Membership and List of Meeting Dates
Appendix 2 – Case Studies
Appendix 3 – HCC Drainage Action Plan
Appendix 4 – Interim Pitt Report Summary
Appendix 5 – Unicorn Project Report
1.1 Purpose of the report: The Overview & FRAMEWORK FOR SCRUTINY:
Scrutiny Committee agreed to add this Issues and Questions to be addressed:
topic to the Environment Scrutiny
Committee‟s work programme. It was 1. Why are we doing this now? A number
noted that the Director of Environment of factors could intensify the problem,
has raised land drainage as a key issue including
for the Environment Department. This a prediction of shorter sharper rainfall
should be seen against substantial the forecast of the increase in
additional spending on Herts Highways households
badged as Herts Extra. 2. To address the impact of poor drainage
1.2 The purpose of the Topic Group was to traffic flow on what is already a very
examine the impact of land drainage. busy network
The Group held a number of meetings
the physical state of the highway
and took evidence from Hertfordshire
damage to property, including HCC
County Council (HCC) officers, external
3. Consider the responsibility of agencies
expert witnesses and a visit to the
in respect of the maintenance of:
Water Courses and other water falls
1.3 It is a specific report of an all-party five Land Drainage
member Topic Group established by Public Sewers
Hertfordshire County Council‟s The highway drainage system and its
Environment Services Scrutiny elements
Committee. 4. Clarify and explore the robustness of
HCC‟s involvement in Inter Agency
1.4 The remit of the topic group is contained Working, including the responsibility for
in the Framework for Scrutiny (as statutory enforcement
outlined on this page). A copy of the full 5. Explore how this issue impacts on
scoping document for this scrutiny can HCC‟s Challenge of making
be viewed on the County Council web- Hertfordshire An even better place to
site at live and work and Community
www.herstdirect.org/yrccouncil/civic_cale Leadership role
1.5 An area of particular concern was the impact of Climate Change on land
drainage. The Group established that for the UK there are no long-term
trends clearly apparent in the amount of annual rainfall the UK receives.
However, there is a clear trend in the proportion of rainfall received in the
winter relative to the summer so that winters over the last 30 years have been
getting wetter, whilst summers have been getting drier.
1.6 The most appropriate information on how climate change will impact on
rainfall can be found within the UKCIP02 climate change scenarios for the
United Kingdom. These were produced by the UK Climate Impacts
Programme (which is funded by the Government) in 2002 and outline the
potential changes in our climate over the next century. The scenarios are
based on historical weather data and robust computer modelling techniques
from the Met Office. From these scenarios, we can expect to see in the East
up to a 15% increase in winter rainfall
a 15-30% decrease in summer rainfall
1.7 It is important to recognise these shifts in rainfall between seasons will
probably have physical implications for the capacity of drainage systems as
well as their maintenance in the future.
1.8 In terms of rainfall patterns, particularly short sudden rainfall, it would be very
difficult, if not impossible to predict at the local scale for the future because it
is often very localised and subject to a range of factors. However, the
UKCIP02 scenarios do suggest that for the UK in general winter depression
tracks (in persons terms „winter storms‟) may be likely to increase in intensity
and frequency in the future.
1.9 The new scenarios, due from UKCIP08 IN November 2008, will provide more
locally specific information and will provide a range of plausible changes in
climate with an estimated likelihood of occurrence, which is very well suited to
1.10 Minutes and papers from meetings of the Topic Group can be obtained from
1.11 Having considered the evidence, the Group agreed a series of
recommendations on behalf of the Environment Scrutiny Committee. The
Overview & Scrutiny Committee will then consider whether to refer these to
one or more of the following:
Leader of the Council
Chief Executive of the Council
Executive Member for Highways, Transport & Rural Affairs
1.12 A summary of the Group‟s recommendations is listed.
Recommendation 1 To improve communication and liaison between agencies
HCC Environment need to facility a 1 Day Seminar of key
partners to establish robust on-going relations between
Recommendation 2 Hertfordshire Highways Action Plan to be introduced
during this financial year. Additional revenue funding is
provided to restore routine programmes of drainage
maintenance, and to develop an asset management
Recommendation 3 The good practice shown by a district with regard to
planning and development and riparian maintenance
needs to be adopted throughout Hertfordshire who to
Recommendation 4 OSC needs to commission scrutiny of flooding to
complement the work of this topic group, especially in light
of the presentations made at the Hertfordshire Resilience
Conference (6 March 2008
2. Summary of Evidence
2.1 To help develop an understanding of the issues the Group requested in-depth
studies on two recent incidents in the County: one in a well known hot spot
and a totally unexpected occurrence. The case studies were concerned
details of the flooding episode at Barley (14 June 2007) and regular flooding
on the B158 Lower Hatfield Road.
2.1.1 Barley Flooding: the Group identified a number of key issues including (the
Herts Highways included in italics):
Co-ordination of Cross Boundary working – Hertfordshire Police was
preventing motorists entering the flood water whilst Cambridgeshire
Police was not stopping motorists entering the flood water. Perhaps
this is a matter for closer liaison between the police authorities.
Would the response need to be different if a similar event occurred on
a major road? The flooding and embankment slip occurred on a minor
rural road, which was closed for many weeks whilst remedial work was
carried out. An embankment slip on a main road is unlikely. Severe
flooding however could have a major impact on traffic flow if a main
road was closed or traffic flow impeded
Is there a need for Herts Highways to survey verges for possible
slippage in storm conditions? This would be ineffective and costly.
Even at Barley, an inspection of the embankment would not have
identified cause for action. The failure was caused by the exceptional
weather conditions and failure of the water course. There are known
areas of embankment slippage, even on A roads which are monitored.
What are Hertfordshire Highway‟s responsibilities in regard to
supporting the emergency services in incidents of this nature? In
emergency incidents the emergency services take command. Herts
highways provide support services as required, and as resources
permit. There are regular joint exercises held to test out response
Does Hertfordshire Highways need a more robust database to log
incidents of this nature? The Current HERMIS management system
logs all transactions on the highway from which most reports can be
Where do the costs associated with incidents of this nature get
passed? Not sure – we’ll need a clearer response for the final report
2.1.2 The final costs associated with the Barley Case Study were as follows:
Initial emergency response £6,000
Verge work B1039 Chishill Road £12,000
Landslip Bogmore Road £75,000 Work due to start on
site 3-4 weeks.
Further cleansing of drainage systems £3,000
2.1.3 The Group heard details of incidents of flooding on the B158 Lower Hatfield
Road. The most serious incidents of flooding along this stretch of road
occurred in 1987, 1993 and 2000. There have been problems with the
existing drainage system along the B158 for many years and thus far
Hertfordshire Highways have undertaken remedial works where possible to
repair the existing system. This section of road has continued drainage
problems along its length. A study has been carried out to investigate the
problems and develop solutions. An approach of implementing localised
improvements on the highway, within the control of Herts Highways was
proposed, but this has been challenged by businesses located along the
length of the B158. An holistic approach involving other bodies, principally
the Environment Agency and adjacent landowners, would be required to
achieve a long term solution.and is very costly. Heavy Goods vehicle traffic
travelling along the B158 is not responsible for damaging the highway
drainage network but does drag soil from the road edges onto the road which
contributes to blockages of the drainage system.
2.1.4 A summary of problems contributing to flooding along this stretch of road
Overland run-off from adjacent land;
Sediment material blocking the drainage network;
Flooding of the River Lea resulting in water backing up drainage pipes
2.1.5 Possible ways forward have been identified by the Herts Highways:
Increased co-ordination of activities with external agencies e.g. the
Agree appropriate storm frequency return periods; and design and
implement a drainage system with adequate capacity
Implement an improved maintenance regime concentrating on gullies,
grids and culverts;
Better co-ordinated works programme ensuring that all appropriate
works are carried out simultaneously;
A range of technical options to improve the drainage network.
2.1.6The cost of the holistic approach is estimated to be in the region of £1.2m.
2.2 Hertfordshire County Council (HCC), as the Highway Authority for the
majority of the roads in Hertfordshire has various duties and powers in
relation to flooding and drainage on the highway maintained at public
2.2.1 The Highway Authority is not responsible for flooding or drainage on private
land – this is the responsibility of the owner or occupier of the land. Where the
flooding is caused by inadequate highway drainage, the Highway Authority
may be liable for causing a nuisance. Where flooding on a highway is caused
by another person (e.g. an adjoining landowner), the Highway Authority can
take action against the person responsible. Nuisance water flowing down a
farm track will deposit silt or stones onto the highway. HCC has the authority
to make the land owner prevent this from occurring.
2.2.2 HCC, as the Highways Authority for Hertfordshire, has a common law duty to
maintain the highway and “put the highway in such good repair as renders it
reasonably passable for the ordinary traffic of the neighbourhood at all
seasons of the year without danger caused by physical condition.” The duty
to maintain includes a duty to keep the highway free from flooding and
provide adequate drainage.
2.2.3 Standing water on the road may constitute an obstruction to the highway and
HCC would have a statutory duty to act.
2.2.4 Under the Flood Defence Funding 2003, enforcement responsibilities for
small rivers, main ditches and other ditches moved from local authorities to
the Environment Agency.
2.3 District Responsibilities (the Group may wish to reflect on the comment
from ESC with regard to new developments on known flood areas). The
Head of Planning at Hertsmere Borough Council (previously Chairman of
HCTOA Planning Committee), attended a meeting and provided evidence on
aspects of the planning process that cover land drainage issues. The Group
established that strategic flood risk assessment informs the planning process.
2.3.1 There are three main planning documents:
i) 20 Core Strategic Priorities
ii) Site Allocations
iii) Development Control Policy Document
2.3.2 Sustainability assessment is undertaken throughout the planning process.
More assessment is now undertaken in the than in the past and is carried out
in conjunction with the Highways Authority and Environment Agency. The
Topic Group were informed about a new piece of work called Strategic
Drainage Assessment which is undertaken as part of the Local Development
Framework (this is a statutory requirement). The Site Allocations document is
the most used for the consideration of Drainage Issues. Most
districts/boroughs follow a similar process, although it was noted that cross
boundary work could be further improved by better co-ordinated timescales
for the production of documents.
2.3.3 Planning permission is required for the concreting of driveways and patio‟s in
most local authorities. If planning permission is not granted and the
development goes ahead regardless, the authority has the power to enforce.
However, as this can be expensive and time consuming, local authorities
need to consider what the „best use of resource‟ is.
2.3.4 Development Control Process. The speed of determination of applications
is for small developments – 8 weeks and for large developments – 13 weeks.
For developments of five or more houses, planning approval is unlikely
without a drainage system being included within the proposal. Pre-
negotiation between planners and developers takes place wherever possible.
HCC (strategic, limitations)
2.4 Environment Agency (EA) (members may wish to consider what to
include at this section). The Group had a number of areas to cover when
meeting the EA:
What are the main responsibilities of the Environment Agency in
respect of land drainage and water courses?
What arrangements are in place for carrying out these responsibilities
operationally through planned or reactive maintenance works of the
key drainage channels and water courses by enforcement of the
powers available either directly or through local authorities and other
What are the key issues associated with partnership working?
How is the Agency consulted on large scale development and its
impact at strategic level, local level and case by case?
Forecasting / Climate
What involvement does the Agency have with weather forecasting,
climate change modelling and its impact on land drainage?
What potential implications does a shift in climate have on drainage
2.5 Water authorities
Case Study: Radlett Road, Watford. Thames Waters provided the following
written evidence to the Group.
Brief details of the history of the problem, how far back does it go,
extent of problem, impact on residents and road users
There are 19 properties in Radlett Road and Eastfield Avenue that suffer
from either foul water flooding, surface water flooding or both. Three are
flooded internally and 14 externally. The driver property for the scheme
has flooded six times between 1989, when the first incident was reported,
and 2006. Flooding also occurs to the highway and this leads to run off
into the gardens of the properties.
What is the cause of the problem?
Flooding is due to lack of hydraulic capacity in the foul and surface water
sewers. It is also considered that there is insufficient highway drainage in the
area which exacerbates the problem. The local highway office has
implemented improvements, as far as they are able, to the highway drainage
system, to mitigate property flooding
What is the proposed solution and estimated cost?
Solution on the Byron Av/Eastfield Av SW system involves 127m of new
300/450 sewer and upsizing of 19m of existing 300mm diameter to 450mm
diameter. Solution on the Balmoral Road SW system consists of 210m of
new 450/525/900mm diameter sewer connecting to a 12m diameter. 15 metre
deep tank with pumped return. Foul solution involves 87m of new 450mm
What is the programme for the work?
The project is currently in design phase. The next milestone is March 2008
when we request funding from the board to allow us to proceed with
construction. Construction is planned to commence in June 2008 and
completion is proposed as February 2009.
Why is this problem being addresses now?
Projects on the flooding programme are prioritised according to the flooded
properties SFI, Sewer Flooding Index. This is a measure of the severity and
frequency of the flooding that has been experienced. Radlett Road had a
relatively low SFI however the projects with higher scores were addressed
either in the last Amp period or in year one and two of this five year amp
period (we are currently in Year Three). There remains a need to alleviate
flooded properties year on year, so the projects that with lower SFIs, less
outputs (flooded properties) and greater cost are then considered. Relating to
TW improvements work general (surface water sewers and land drainage)
Is there a prioritisation/ ranking process and how does it work? Can a
list be provided of outstanding problems in the county with an indicative
Partially covered this above. Currently there are no further briefed projects in
the Watford area. We have a couple of projects in the St Albans Area but I
understand this is not your patch.
Is there a mechanism for highway flooding problems related to the TW
sewer outfall to be included in the programme?
If during the course of our investigation, we discover a highway drainage
problem is contributing to the overall flooding issue, then we will bring this to
the attention of the highway authority and hope that they will resolve the
issues with their infrastructure. If funded by the HA, highway drainage works
could be included within the scope of our works on site in order to be most
cost effective, minimise disruption to the public, and ensure a joined up
approach between the HA and Thames, as there is nothing worse than
flooding continuing after we've constructed a multi million pound scheme just
because a few extra gullies are required.
In terms of the TW programme what are the nominated area contacts?
Details were provided to Herts Highways.
Are they aware of our contacts responsible for road space/ works
No not really. The Principal Project Manager has requested a meeting with
the Highways Service Manager (South West Herts) and his equivalents for
the other areas in Herts and , if appropriate, their Manager. The meeting
would be to discuss how we can all interact in the future and give a more
general view of Thames Water and what we are doing and how inadequate
Highway Drainage is becoming more and more of a problem for us when
resolving flooding. Is this something Herts Highways would be interested in
meeting us on?
2.6 HIGHWAY DRAINAGE – CURRENT PRACTICE
2.6.1 A well maintained drainage system is vital to the effective management of the
highway network.and is an important factor in safety, the free flow of traffic
and the condition of the road surface. An extensive drainage system has
been established, over the last hundred years or more, but records of the
systems are poor. In urban areas the drainage system commonly comprises a
network of road gullies, connected to highway drains and surface water
sewers, in rural areas, typically, grips cut through the highway verge into
ditches. The highway drainage systems are often dependent on outfalls
which are the responsibility of the Environment agency, Thames Water or
2.6.2 The Group clarified that 95% of problems with drainage systems are caused
by blockages. Cleansing and repair work resolves the problem in the majority
2.6.3 Only road gullies are maintained on an annual/cyclic basis. The frequency of
gully emptying is under review with proposals for an enhanced cleansing
frequency of vulnerable gullies and a reduced frequency in urban (often
difficult to access) streets Through the annual programme, defects are
recorded for later action. A defect at the gully is often an indication of a more
general problem with the system into which it feeds
2.6.4 Flooding problems are reported by the public at times of heavy rainfall. These
are responded to through the Cat 1 service, but the cause of the flooding is
not always resolved. Drainage defects are identified from public reported
faults or local officer knowledge. Monthly and ad hoc cleansing using a Vactor
unit is used to investigate defects and cleanse the system, which resolves the
problem in most cases.
2.6.5 Drainage problems which cannot be resolved simply are put on a list to be
prioritised for funding as a drainage scheme. The budget (2007/08) for such
work was £800k. It is expected to be between £800-900k (2008/09). Whilst
some drainage schemes can cost over £1m, the majority cost less than
£100k. A huge capital investment would be required to replace Hertfordshire‟s
2.6.6 The reduction of revenue funding has resulted in reduction of routine
maintenance programmes such as grip and ditch clearance, clearing out
soakaways etc. Drainage systems are maintained only when a problem is
occurs. The need to quantify the level of service required and the cost of
maintaining that service was identified. At present there is insufficient
information to enable a choice to be made on the most effective maintenance
2.6.7 We need more on intro for this item. Information systems are expensive. It
can cost £2.5k to survey the drainage per kilometre of road and Hertfordshire
has 5000km of roads. A survey of the A road drainage system would cost in
the region of £125, 000
2.6.8The support and assistance provided by Thames Water regarding the
resolution of highway drainage issues is varied with the resolution of a
number of problems around the county are awaiting their cooperation. It was
noted that new legislation is being introduced which enables the scrutiny of
utility companies by local authorities.
2.6.9Traffic Regulation Orders are used to close roads in order to carry out
maintenance. In some areas HCC gains the cooperation of residents by
undertaking a letter drop.
2.7 HIGHWAY DRAINAGE ACTION PLAN
2.7.1Herts Highways have developed a drainage action plan for the forthcoming
year (2008), which will be constrained by the funding available. The main
improving the methods of capturing and recording and utilising
information relating to drainage systems;
prioritisation of, and attention to, regular flooding hot spots/problems;
implementation of a planned routine maintenance regime, when and
where possible . Mapping and condition survey of drainage on the A
road network would be a start
establishing consistent and best practice across the county with levels
developing and utilising stakeholder contacts to improve working
2.8 Interim Pitt Report
During August 2007, Sir Michael Pitt was asked by ministers to carry out a
review of the flood-related emergencies which occurred during the summer of
2007. An interim report has been published to achieve three objectives:
to identify issues which need urgent action;
to set out the direction for the remainder of the Review; and
to provide a document for consultation before the final report is
published summer 2008.
2.8.1 The floods during June and July 2007 were a wake-up call. The three months
from May to July were the wettest since records began and the events that
followed have been linked to the deaths of 13 people. They also resulted in
damage to approximately 48,000 homes and 7,000 businesses. Power and
water supplies were lost, railway lines, eight motorways and many other roads
were closed and large parts of five counties and four cities were brought to a
standstill. From an emergency response standpoint, this was a new level of
challenge. The flooding triggered a series of emergencies which stretched
local resources to the limit. Taken from the Executive Summary of the Interim
Report (the full summary can be found at Appendix X).
2.8.2The Group considered the outcomes of the recently published interim Pitt
Review, assisted by the Head of Safety, Emergency Risk Management Unit
(SERMU) and the Assistant Chief Officer: Service Delivery, Fire & Rescue
Services. The Pitt Review identified 15 urgent recommendations and 72
2.8.3If Hertfordshire had received the level of rain experienced in other parts of the
country during the summer 2007, serious flooding could have occurred.
Hertfordshire‟s location at the top of a catchment area means that the time
between rain falling and possible flooding is very short. This makes warning
residents and businesses of possible flooding very difficult.
2.8.4 Hertfordshire County Council has responsibilities under the Civil
Contingencies Act and invites District and Borough Councils to manage the
distribution of sandbags. Sandbags are not the best devise for preventing
flooding but do provide reassurance to the public.
2.8.5 Project UNICORN is an example of joined up working between HCC and
Middlesex University. The project has been running for the last three years
and identifies areas at „high risk‟ of flooding within the county. These include
care homes and schools who have signed up to the scheme. It was noted that
the sharing of information by utility companies is essential in order to identify
the impact of assets being lost during flooding events.
2.8.6 Fire & Rescue Service possess high volume pumps, as part of a national
network, which were deployed to Gloucestershire to help with the summer
floods. Fire & Rescue Service works outside of the traditional boundaries of
Hertfordshire in such events.
2.8.7 The difference between Flood Response and Water Rescue were clarified.
Fire & Rescue Service would do this but receive no funding and there is no
legal requirement for them to provide this service. Support is provided by
Water Rescue Experts who are voluntary and support can also be provided
by the RAF and RNLI.
After assessing the evidence received the Group reached the following
There is a lack of clarity about the priority and responsibility for
maintenance of critical water courses.
infrastructure is in place that is not effectively maintained at the present
frequency of gully cleaning should be considered – maintenance
programme for the 160,000 gulley‟s in Hertfordshire
mapping of the current drainage network – location of sensitive /
how to respond to weather events that occur which are very difficult to
cleaning of grips on rural routes – currently not undertaken
7. Glossary of terms & abbreviations
Cat 1 service
Environment Scrutiny Committee
Hertfordshire County Council: works with local
organisations and central government to deliver a range
of local services to over a million people, who live, work
and travel in Hertfordshire.
Riparian Owner As a riparian owner your responsibilities include the
Responsibilities maintenance of the bank and bed of your section of
watercourse, in order to avoid any obstruction of flow
in the watercourse;
You must accept flood flows through your land, even
if these are caused by inadequate capacity
downstream. There is no duty in common law for a
landowner to improve the drainage capacity of a
Any structures you own, culverts, trash screens,
weirs and mill gates, must be kept clear of debris.
Riparian Owners You have the right to receive a flow of water in its
Rights natural state, without undue interference in quantity
You have the right to protect your property against
flooding from the watercourse and also to prevent
erosion of the watercourse banks or any structures.