A FLOOD protection scheme in Holmwood, Langholm may rise by up to £150,000, an increase of nearly 40 per cent on the original cost.
The original estimate of £250,000 has now been revised up to between £375,000 and £400,000 after groundwork investigations forced a rethink.
Dumfries and Galloway Council’s economy, environment and infrastructure committee is being recommended to incorporate Holmwood into the Langholm flood protection plan.
The report on Langholm’s scheme said the review of costs and benefits was almost done and estimates showed the cost to be £7.4m and the benefits £9.7m.
This meant a benefit cost ratio was possible and the scheme would be eligible for Scottish government funding.
The final costs would be reported to policy and resources committee to consider the financial implications to the council in progressing the scheme.
The first meeting to select the option or options to be taken forward was held last week in Langholm and this will be followed by a three-day community engagement event in Langholm in July.
A presentation will be made to the community council next January followed by a public engagement event in February.
The report said works to protect properties at Holmwood from water run-off from the surrounding hills would involve installing a combination of drains and berms to intercept overland flows west of Holmwood Drive to discharge into the Meikleholmside watercourse.
This would alleviate the flood risk to properties and gardens in Holmwood Drive and Meikleholmside.
The consultants said additional ground investigation would be needed to inform the detailed design and this could cost up to £40,000.
If the investigation revealed a significant amount of rock or other adverse conditions, the cost of installing the drainage works would go up.
Estimates were also being prepared for a previously unknown Scottish Water main diversion, ScottishPower works and the cost to the consultant to prepare a revised design.
Steven Herriott, head of roads and infrastructure, said: “The final costs could be between £375,000 and £400,000 or higher if there are adverse ground conditions.
“On this basis, it is considered that the projected costs of a scheme could outweigh the benefits and may not be a value for money project.
“There is an option to align progressing Holmwood with the Langholm scheme. In this way, savings could be made in terms of project management because the consultants, RPS, have been appointed for both.
“It’s recommended the ground investigations works are done at this time to inform the cost estimate for Holmwood.
“We appreciate properties will be left at risk from surface water run-off and the council will look to see whether any property level protection can be provided and flows can be partially diverted.
Faw Side Community Group, which is fighting plans by Community Windpower to build 45 turbines in the Ewes valley, attended Langholm community council’s meeting on Monday and asked whether RPS had been instructed to take the proposed windfarm into account.
They are concerned that extra run-off from the hills could cause greater flooding downstream, particularly in Langholm.
More water would run off because peat would be dug out, ditches cleared and roads built, creating a greater area of hard surfaces.
In a statement the group asks: “If Faw Side development plans have not been taken into account by RPS, how does the council propose to accommodate these developments. This is likely to mean reworking the RPS report findings, including extra costs.
“What assumptions are being made by RPS Consultants when they make their recommendations on the scope of flood prevention measures which need to be put in place?
“What assumptions have been made about the volumes of water which will come off the hillsides around the River Esk and Ewes Water. Are these measured or predicted values?