In purely quantifiable monetary terms, it is clear from these estimates that the project has a very significant capital cost of circa €46m and that the quantified annual net economic benefits are at most €323.5k per annum. The latter thus covers the annual revenue costs of €308.8k per annum only. Applying any cost benefit analysis, whether payback period or net present cost, will result in a large negative for the project.
The justification of the project therefore relies largely on the unquantifiable benefits associated with the project and the disadvantaged area in which these will occur.
Department of Arts, Heritage and the Gaeltacht Restoring the Ulster Canal from Lough Erne to Clones: Updated Business Case February 2015
The project will give this border region, which has suffered greatly from economic deprivation, a much needed boost in terms of job creation and tourism. There is significant potential for growth in the waterways based tourism market and I have no doubt that the reopening of this section of the canal will help to attract significant numbers of visitors to the area.
Heather Humphreys quoted in Department of Arts, Heritage and the Gaeltacht press release Minister Humphreys secures Government approval to restore Ulster Canal from Upper Lough Erne to Castle Saunderson 24 February 2015
If “quantified annual net economic benefits are at most €323.5k per annum” for a sheugh running all the way to Clones, it is hard to see how a shorter sheugh to Castle Saunderson is going to result in “a much needed boost in terms of job creation and tourism”.
But that’s where the unicorns come in: it will all happen by magic.
Irish waterways history 
perhaps some of the massive financial surplus brought in by Tralee’s fully functioning Ship Canal could be shared out with other waterways, to further enhance this exponential growth spiral?