[…] the [Irish] Board of Works grew, from comparative insignificance in 1831, to become for nearly half a century the chief agency through which government influenced Irish economic development. 
The Board of Works, now the Office of Public Works, was responsible in 1848 for making certain grants and loans and for:
- public buildings including government offices, Maynooth College and lunatic asylums
- roads and bridges
- drainage and land improvement
- fisheries including sea fisheries and those of oysters, salmon, trout, eels and pollan
- certain piers and harbours
- some inland navigations.
Sometimes drainage and navigation work overlapped, as in the Ballinamore and Ballyconnell District. But we are concerned here with the neighbouring Lough Oughter district, which is upstream of Belturbet in Co Cavan. Belturbet is the head of the River Erne navigation, although Waterways Ireland would like to extend navigation to Lough Oughter. (I wonder whether that has higher or lower priority than the canal to Clones, which would start not far from Belturbet.) To get an idea of the geography, go to the Ordnance Survey Ireland website and select Ortho 2005 from the list on the right. You should see the town of Belturbet at the top of the page; you can then fly upstream (south, towards the bottom of your screen) along the Erne to Lough Oughter. There is quite a lot of water up there. As A R G Griffiths said:
Almost every county in Ireland had land that was bog, mountain or flooded by rivers. 
And the neighbouring counties of Fermanagh, Cavan and Leitrim had more than their share of water.
Drainage resulted in land reclamation: more land, so more, and more valuable, crops. As well as that, the work created employment in rural areas, where there were few other opportunities to earn an income. So the Board took it seriously: in the Ballinamore and Ballyconnell District in 1849 there were up to 4000 men employed on one day, with 1849 on one day in 1851 on Loughs Oughter and Gowna. 
That said, the employment creation aspect was not as successful as it might have been: interruptions to the flow of funds meant that men had to be laid off and sometimes, by the time funding resumed, they had left the district. Farming took priority, so drainage work had to be scheduled when demand for agricultural labour was low, but it couldn’t be done when rainfall was too high. Emigration took some workers away; then there was competition for labour from the railways  and even from the army .
Thomas John Mulvany CE
T J (Thomas J, Thos J) Mulvany was a chartered engineer and the youngest brother of John Skipton Mulvany and of William Thomas Mulvany, who was Commissioner for Drainage at the Board of Public Works. After being attacked by a House of Lords committee for charging landowners too much money for drainage work, William Thomas retired on a pension and went to Germany, where he opened coal-mines on the Ruhr. David Malcolmson of Portlaw was an investor, and that is said to have resulted in the introduction of the Portlaw roof to the Ruhr.
Thomas J Mulvany joined his brother in Germany in 1855, but for some years previously he was an energetic District Engineer working on drainage schemes. His concept of time of concentration was the basis for the rational method of prediction of flood peaks; he read a paper “On the Use of Self Registering Rain and Flood Gauges in making Observations of the Relation of Rainfall and of Flood Discharges in a given Catchment” to the Institution of Civil Engineers of Ireland in February 1851. 
In 1849, T J Mulvany reported that he had two dredgers at work:
A dredging-vessel, worked by men, which was purchased for the use of the Lough Oughter district, has been transferred to this [Ballinamore and Ballyconnell] district, and is now employed clearing away the dams etc at Aghalane. A spoon and bay-dredge has been also fitted up, to work Demagore and Carrickalease, and it is in contemplation to provide one or two additional dredgers, worked either by steam or manual power […]. 
Boat-building at Belturbet
In 1850  he set up workshops at Kilconny, which is the suburb of Belturbet on the west side of the Erne. He tested several designs of screw-pumps and got 21 of the best type, horse-operated, made at the workshops:
These pumps, and all the machinery connected with them, except the castings, were constructed in the Board’s workshops at Belturbet …. 
In the following year he became even more ambitious:
The workshops at Belturbet have been kept in constant operation during the year, and have been found to be a great convenience in enabling us not only to effect repairs of machinery, etc, with a great saving of time and expense; but also to execute a variety of important works in a more satisfactory manner and at considerably less cost than it was found practicable to get them done by contract.
In addition to a large amount of work for lock-gates, we have constructed an iron lattice bridge for the Longford district, 43 feet span and 12 feet roadway; three barges, fitted up with spoon and bag apparatus for dredging away dams in the Lough Oughter district; a large steam dredger, 80 feet long, and 15 feet 6 inches wide, for the Ballinamore and Ballyconnell district; and two scows or tenders for this dredger, 48 feet long and 15 feet wide, on deck.
The dredger has been launched, and fitted with steam-engine, boiler, and other machinery, and will shortly be ready for work. Two additional screw-pumps have also been constructed since the date of my last Report, and great advantage has been experienced from the working of those provided in the preceding year. 
In 1853 the workshops produced an iron lattice-bridge and eight accommodation bridges of wood and iron, as well as an anchor boat for the dredger, and work began on a “new set of iron buckets and links” for the dredger.  However, there was less work in the following year: the buckets and links were completed, the dredger was maintained and smith’s work for locks and sluices was carried out.  That was Mulvany’s last full year; the report in the following year was written by his successor, Martin Farrell CE, and the workshops were closed in 1856.  In 1858 Farrell had the mill at Ballinamore fitted out as a blacksmith’s shop:
[…] several burst plates in the hull of the “C” dredger have been replaced with new plates. 
The dredgers and the distillery
In 1857 it became necessary to get the dredgers (including the “C” dredger, which had come from the Shannon) up to Lough Oughter. But the river was not navigable above the bridge and the distillery weir was just one of several obstacles to navigation. Here is the distillery; select Historic 6″ or Historic 6″ B&W to see it. Here is how they got the dredgers up the river:
For the purpose of bringing the steam dredgers from the Ballinamore and Ballyconnell District into Lough Oughter, it was necessary to form three levels by means of dams in the navigation course that had been partially prepared below the Belturbet weir, and as the level of Lough Erne had fallen very low at the time that the dams were being prepared, it was necessary to cut a channel for the dredgers through a short shoal a little below the Belturbet bridge.
The “C” dredger arrived from Leitrim, near the Shannon, on the 5th of August, and the dredger built at Belturbet, which had been lent to the Londonderry and Enniskillen Railway Company to have some dredging work done near Enniskillen, arrived on the 6th of August. They were both, with their barges, raised through three artificial levels (a perpendicular height of eleven feet) without accident or any interference with the level of water for the distillery.
Two spoon and bag dredgers were also brought from the Ballinamore and Ballyconnell District to dredge the tops of the dams, in order to get a sufficient depth of water on them for the steam dredgers. The dams nearest to Lough Oughter were first engaged in, as being likely, in freshes, to have a greater depth of water on them, and to give greater and more immediate relief to the land. 
That method of getting the dredgers up the river reminds us of the thirteenth-century Priory at Athassel on the Suir ….
6. J C I Dooge “The Development of Hydrological Concepts in Britain and Ireland between 1674 and 1874” in Hydrological Sciences—Bulletin—des Sciences Hydrologiques XIX 3, 9/1974 consulted online at http://iahs.info/hsj/193/193009.pdf February 2011
14. “Extract from the Annual Report of Mr Martin Farrell CE, District Engineer, for the year 1858” in Twenty-Seventh Report from the Board of Public Works, Ireland, with Appendices, 1858 Dublin, HMSO 1859
15. “Extract from the Annual Report of Mr Martin Farrell CE, District Engineer, for the year 1857” in Twenty-Sixth Report from the Board of Public Works, Ireland, with Appendices, 1857 Dublin, HMSO 1858
You may be interested in the role of the cads and bounders of the Ulster Canal Company in getting the Junction Navigation (later the Ballinamore & Ballyconnell Canal and later still the Shannon–Erne Waterway) built at other people’s expense.