AN order to infill a controversial waste dump will cost Glasgow City Council more than four times the original estimate.

The council will commit almost £21million to restore the Cathkin Landfill Site by September next year after being told to close it.

Last year it was ordered by South Lanarkshire Council to stop dumping at Cathkin, which is just outside its boundary and in the immediate vicinity of the Glasgow 2014 Games mountain bike course.

A Scottish Government planning reporter rejected a Glasgow appeal against the decision.

At the time the city council told the reporter it would have to find £2.6m to pay for commercial landfilling and another £5.5m to infill Cathkin as a result of the closure.

But a new report shows that estimate has quadrupled, with a suggestion they could rise further.

Part of the cost will include special measures to maintain landfill gases, with the landscaping including planting, fencing, remediation and restoration of water retention lagoons.

Following completion of the remediation and restoration, the city council will have to maintain and manage the site for up to 30 years, as required by the Scottish Environmental Protection Agency.

Glasgow had hoped to keep the landfill open until 2016, when a new energy-from-waste plant comes into operation.

Now the city will have to spend millions putting its rubbish into commercial landfill over the next three years.

The report by Councillor Alastair Watson, political head of land and environmental services, states: "The city council already had plans developed for the remediation and restoration works in the knowledge that landfill operations would cease at some point and these plans have now been finalised, costed and satisfy all necessary legislative and statutory consents.

"Forthcoming legislation requires a significant policy change in the continued reliance of landfill as a means of waste disposal over the coming years.

"The new Glasgow Recycling and Renewable Energy facility and continuing focus on recycling will help Glasgow communities satisfactorily meet this challenge."

Meanwhile, the council is to contribute £1m towards the cost of a new mountain bike and activity centre in the Cathkin Braes.

The £3.34m project, which will create 18 full-time equivalent jobs, will see the conversion of a B-listed church and the derelict site of five former multi-storey flats in Castlemilk into a community facility including bike services, a cafe, training space and a shop.

It is intended to comple- ment the Glasgow 2014 mountain bike course nearby.

The council said: "Despite its significant growth in recent years, mountain biking is not easily accessible to numerous communities in the city."