High housing targets are set to worsen flood risks in Barnet by putting more pressure on drainage systems, a council report warns.

Pressure to meet “the third-highest national housing targets” is leading to “rapid urbanisation” and “unprecedented population growth”, exacerbating the effects of climate change, the report says.

It adds that Barnet Council needs to protect floodplains and ensure all new development proposals include a “robust surface water drainage strategy”. A government housing formula sets a target for Barnet to build more than 5,300 homes per year, although the council’s new Local Plan adopts the London Plan’s minimum annual target of 2,364 homes.

The report, which was presented to the environment committee on Tuesday, sets out the council’s responsibilities and progress in tackling flood risk. It comes after Labour opposition councillors warned that overflowing drains and sewers in the borough posed a “serious health and safety issue” and urged the council to work with water companies and other organisations to deal with the problem urgently.

Geoff Mee, the authority’s executive director of environment, told the committee the council had a “very serious problem” with making sure it keeps drainage systems clear.

He explained that the council was looking to map out where its system of 30,000 highway gulleys lead to, and further investigation using CCTV cameras was likely to show “a good proportion” had failed.

The council has secured £6million to help reduce the risks of flooding within the Silk Stream catchment area over the next six years. It has also launched a scheme to remove artificial river banks along Burnt Oak Brook in Watling Park. Further flood-reduction schemes are expected to be implemented in Muswell Hill and Mill Hill over the coming years.

Under questioning from councillors, the director of environment said a “comprehensive flood risk mitigation plan” for the borough would be presented to the committee by the autumn.