I am advised that the National Parks and Wildlife Service (NPWS) is the several fishery owner (on behalf of the State) of the relevant fishery and that the fishery is leased by NPWS to the body referred to by the Deputy.
I understand that development permission would have to be sought from the fishery owner (NPWS) in the first instance.
Inland Fisheries Ireland operates the Salmon Conservation Fund which provides for development works. Applications for projects under the Fund can be made to IFI which are then considered in line with the criteria for the scheme. These criteria are available on the IFI website: www.fisheresireland.ie. The acceptance of an application would be subject to permission for development works from the fishery owner.