The Isles of Scilly Council Infrastructure & Planning department is forecast to overspend by nearly £383,000 this year.
The areas of waste, water and the airport are all over budget, according to the 3rd quarter Financial Report for February 12th's Council meeting.
The water service is overspending by £272,635, due to "significant additional costs associated with the water shortage during the summer [and] significant additional overtime due to operational requirement and work in preparation of the South West Water transfer".
It was noted in the report that the income from water services is still more than the direct costs of delivering the service but for the current year the surplus that contributes towards support services costs and management costs will not be delivered in full.
The airport is expected to have a £122,537 overspend due to fewer than expected passengers, equipment repairs and training costs of a new Air Traffic Controller and replacement Fire and Rescue Duty crew.
Meanwhile, the waste and recycling operation is overspending by nearly £89,773, mainly due legal costs from a contractual dispute over the transfer station project.
However, the Fire and Rescue Service is underspending by almost £95,788 and most other departments are predicting an underspend, with an overall forecast of a net underspend of £64,000 for the year.
The Council’s Lead Member for Place Steve Sims said the infrastructure budget has been put under significant stress this year.
He said: “We all know about the unrelenting beautiful summer days which caused significant and potentially very serious long-term supply issues, which had to be dealt with there and then.
“The legal costs re the transfer station were unfortunate but had to be dealt with. The airport budget is obviously susceptible to unexpected variance in passenger numbers and airports for very good reasons have to be compliant. Staffing, particularly ATC, and equipment are heavily regulated and issues have to be dealt with quickly and this year has been an expensive one.
“So while unpalatable, the majority of the extra costs could not have been predicted. I'm delighted that there has been such a big saving in the Fire & Rescue budget, which hopefully will be carried forward into subsequent years.”