Hundreds of bridges and roads were damaged and numerous several buildings and homes were flooded due to the large volume of rain.
Around 60% of the rainfall expected for the entire month of August fell in just nine hours.
About £12.5m is to be spent in Co Derry and Tyrone by the Department of Infrastructure in Northern Ireland (DfI), while Donegal County Council estimates it will spend €20m (£18m) – an increase of €5m (£4.5m) on this time last year.
Work is continuing in both jurisdictions a year after the flooding.
Three roads in Northern Ireland are still closed because of damage to bridges – Ballynameen Bridge in Church Street, Claudy; the Glenrandal Bridge in Claudy; and a bridge on Dreenan Road in Beragh.
The DfI estimates repairs will be completed by October this year.
In the Republic, between 60-70% of the estimated €20m repair bill has been spent so far.
The Housing Executive confirmed earlier this week that all its tenants forced out of their homes by the flooding have now returned.
They were put up in mobile homes while their homes were repaired.
It is currently playing its home games in the Irish League at Derry City’s Brandywell ground.
‘Stute’ have been looking for a new ground and have earmarked a possible site in the Waterside.
However, it could take up to three years before the work on the new ground could be completed.