CONCERNS have been raised over the potential increased risk of sewage overflows into a river if a proposed development of 20 bungalows in a village in Cornwall goes ahead.

A planning application has been submitted to Cornwall Council for the development on agricultural fields in Trewoon, on the outskirts of St Austell.

St Mewan Parish Council has requested further information about the proposal from the Cornwall planning department.

The parish council wants assurances from the department and from South West Water that “the existing main sewerage network has sufficient capacity to accommodate the additional housing associated with this development”.

The parish council, in comments on the Trewoon plan, said: “Lower Tregongeeves, Polgooth, is already subject to persistent and serious sewage flooding issues. These incidents occur two to three times per year and have a direct impact on nearby residential properties and the local environment.

“Most recently, South West Water attended the site with emergency tankers between December 13 and December 24 to manage sewage levels and prevent overflow into the river at Lower Tregongeeves.

“It has been identified that the balancing tanks were unable to cope with increased flows from upstream, resulting in sewage discharging and flooding. This raises significant concerns that the existing infrastructure is already operating beyond its intended capacity.”

The parish council wants confirmation “that the existing sewerage infrastructure, including balancing tanks, has adequate capacity to manage additional flows from the development without increasing the risk of flooding or environmental pollution”.

And parish council also wants an assurance that any necessary upgrades or mitigation measures would be completed prior to people moving into the proposed bungalows in Trewoon.

The parish council warned: “Without such assurances, there remains a serious risk that further development will exacerbate an already unacceptable situation for existing residents in Polgooth and the local water environment.”

The planning application is for land at the rear of Badger's Watch, north of Trevanion Road in Trewoon. The site had development on two of its boundaries. A range of one-, two-, three- and four-bedroomed bungalows would be built.

Disappointment has been expressed by a member of the public that only 30 per cent of the bungalows – six in total – will be affordable housing, with the rest being open market properties.

However, a resident living next to the development site has voiced strong support for the proposal, saying: “Cornwall is currently facing a well-documented shortage of housing, and small-scale, sustainable and deliverable schemes such as this are essential if we are to make meaningful progress toward meeting local and national housing targets.”

As part of public consultations about the plan, letters were sent to 132 neighbouring households telling them about the proposed development and inviting them to a consultation event which was subsequently held in Trewoon Village Hall.

Red Planning, the agents from Hay Common Developments, said the response to the public consultations about the plan had been “overwhelmingly positive, with only a few people showing concern for drainage and flooding”.

The agents said: “This concern has been carefully considered when implementing drainage strategies.”