The Public Rights of Way Officer will be in attendance to provide the Panel with a statutory annual update on:
· Flood Risk Management
Recommendation: that Members
note the information provided.
Minutes:
The Public Rights of Way Officer
provided the annual update on flood risk management. Flood risk was a combination of the
probability (likelihood or chance), of an event happening and the consequences
(impact), if it occurred.
Flood risk was dependent on there
being a source of flooding, such as a river, a route for the flood water to
take (pathway), and something that was affected by the
flood (receptor), such as a housing estate.
Without a pathway linking the
source to the receptor, a flood might be a hazard, but not a risk. This concept was
known as the source-pathway-receptor model.
Return periods were often used to
describe how often a flooding event might occur. So for example, a 1 in 50-year flood
had a two percent probability of occurring in any one year.
Flooding sources included:
coastal and erosion, river (fluvial), surface water (pluvial) flooding and
groundwater. There
was also potential risk of flooding from failure of infrastructure, including
reservoirs and sewer systems.
Over the last two years,
Middlesbrough Council had moved from a reactive to a planned response to flood
risk. The
Council had been receiving an increased number of requests about blocked drains
and spent a great deal of time reacting to freeing those blockages.
Key tree-lined routes had been
identified and were swept more often to try and prevent fallen leaves blocking
gullies. In
advance of any predicted storms or bad weather, grills
and outfalls in becks were checked and cleared.
A new programme of regular road gully cleaning had also been implemented.
The Council was working with
Northumbrian Water Limited (NWL) on Stage 1 and Stage 2 studies to identify
areas that were at high risk of flooding.
In addition a programme of
highway drainage and culvert surveys was also being
undertaken.
The Council also worked with the
Environment Agency (EA) to identify properties at risk of flooding, the source
of flooding and how this could be mitigated. Flood alleviation schemes had been
completed at Saltersgill/Beechwood fields and Cornwall Close. An outline business case for an
alleviation scheme had been submitted in respect of Ormesby Hall and a study
was being undertaken at Shevington Grove.
Members were
shown photographs of the schemes at Saltersgill/Beechwood and Cornwall
Close where bunds had been installed to hold back excess water and allow it to
drain away naturally to avoid the area flooding.
There were approximately 27,000
gullies in Middlesbrough which required ongoing maintenance. Surveys had been undertaken to measure
the silt levels in the gullies and how quickly the gullies filled up with silt
again after cleaning. A
cyclical programme of drainage cleansing had been devised
according to need, ensuring that those gullies that filled up with silt the
quickest were cleaned more regularly to prevent any blockages.
The gulley network had been
divided into different areas – main roads, rural, town centre and estates. It was a 3-year
cycle and time was built in to the regular programme to enable the Council to
react promptly to any reports of blocked drains. Members were shown
a breakdown of the programme by Ward area.
It was clarified that older
housing estates were more likely to have a combined system for surface water
and sewage whereas new developments had separate system. Northumbrian Water were usually
responsible for the main drains under the roads.
The Officer invited Councillors
to report any flooding issues in their Wards to him. In relation to climate change, and the more
regular occurrence of storms, the probability calculations had been updated. Housing Developers
had to attenuate for a 1 in 100-year storm plus 40% for climate change. The Environment
Agency updated their calculations constantly.
The Council had a responsibility
to ensure that new developments mimicked green field run-off – so that there
was no change when a new development was built. Housing Developers had to provide
their calculations to the Council for checking.
Water had to be dealt with at
source and managed to ensure that after a storm the main networks did not flood. In respect of driveways – if they were
extended by more than 5m3, planning permission would be required to ensure a
soakaway was included.
In respect of artificial grass it was unclear as to whether or not planning permission would be needed in the
same way as for a concrete driveway.
The Chair thanked the Officer for
his presentation.
AGREED that the information provided was received and noted.