Sixty or so years ago, after the Shannon had flooded again, the government borrowed Col Louis Ernest Rydell from the US army cCorps of Army Eengineers, a notable flood-tamer of the mighty Mississippi, to advise on this intractable problem.
The Shannon impressed the colonel as one of the outstanding rivers of the world, and draining its basin for agriculture was well worth “aggressive” government effort. It would, he agreed, be complex and costly. He advised on the channels to be dredged in the river’s main stream and in tributaries spread out across a fifth of the country. Then he travelled on, to consider the floods around the long Indus river of Pakistan.
His 1956 report inspired Ireland's drainage works over following decades, including the arterial dredging that left many of our rivers as bare-banked canals. All that, of course, was before "biodiversity", the EU nature directives, the Ramsar wetland agreement, the EU water framework directive, the EU floods directive, the National C-Frams Pprogramme – it stands for catchment flood-risk assessment and management – and the unguessable, implacable change in Atlantic rain.
As migrant winter wildfowl spread out happily across the water, devastated farmers and bankside residents and businesses have reached for someone to blame. If not the ESB and the OPW, then it has to be the National Parks and Wildlife Service, puppets of the bureaucrats in Brussels.
Between SACs (special areas of conservation) and SPAs (special protection areas, for birds), the Shannon corridor is parcelled out into habitats for Europe's Natura 2000 conservation network. They warrant controls and prohibitions: raised bogs that can't be cut, farmland streams that can't be dredged and their banks scalped of bushes, fields that can't be ploughed and reseeded.
The slow Shannon and its banks and lakes are Ireland’s wildlife heartland, partly because its floods have set such close bounds to farming. The meadows of the callows have never been ploughed. Their rare wild-grass communities shelter nesting waders – even, until now, the corncrake. Dwindling in numbers year by year, the males were silent this summer for the first time.
On the lower Shannon an SAC protects a submerged and very rare pond weed among its plants, and a rich mix of threatened riverbank mosses and liverworts. In the same catchment all three species of Ireland’s lampreys breed, their river habitats closely protected, along with the pollan, fish relic of postglacial cold.
Frogs, newts, crayfish, eels, salmonids and their spawning grounds, herons, grebes, ducks and moorhens, otters (mink now, too, alas): the weave of species in the Shannon ecosystem is endless. But people are biodiversity, too, and if some now cry “F*** the wildlife!”, who can be surprised?
Since brutal 20th-century drainage that scooped the life out of rivers, much has developed in "soft" engineering that leaves waterways able to heal. But does the EU habitats Ddirective allow such post-facto surgery in prime SACs and SPAs?
The guidelines to article 6 (4) seem to hint at an option, so far exercised – and rarely – for siting major industries or motorways. “Where the site concerned hosts a priority nature habitat type and/or a priority species, the only considerations that may be raised are those relating to public health and safety [or] to other imperative reasons of overriding public interest.” Such an overriding test, the guidelines warn, “is onerous, and if passed it is likely that potentially expensive compensatory measures will be required”.
That means not payments to flood victims but the creation of alternative habitats to serve the Natura habitat and wildlife network. But there is only one Shannon.
Coping with unpredictable effects of climate change may figure in the "fitness check" on the two nature directives (as they're now called) announced by the European Commission. At its high-level consultation conference in Brussels last month, apprehensive NGO delegates were told that "the practical implementation of an integrated floods-nature management approach remains in the initial phase in many member states" – and also, perhaps, in the commission.
The regular, now more frequent, inundations of the Shannon have shaped maps produced by the C-Fram study (cfram.ie), and the latest floods must refine them further. Since it began, in 2011, the study has amassed an immense amount of data – even to the flood history and behaviour of the little Bunowen, flowing out at Louisburgh, just up the road from us.
The OPW is nothing if not thorough, and the wealth of descriptive detail in the hydrology reports is quite remarkable. But assessing future risks from historical patterns of peak flows and flood events must be problematic. The scaling up of flood flows by 30 per cent in a “high-end future scenario” seems already more than enough, on an island that will always be shaped like a saucer.
Michael Viney's Reflections on Another Life, a selection of columns from the past four decades, is available from irishtimes.com/irishtimesbooks