West-coast gas causes underwater blues

They must have got their tongues around it by now, in the boardroom of Enterprise Energy Ireland "Sru. . . Sruwaddacon Bay!". They may even have come across the story that the Children of Lir spent three centuries paddling up and down this sandy inlet at the corner of Broadhaven Bay. But swans do not appear in their Environmental Impact Statement (EIS), so that's one bird they don't have to worry about.

Bringing the Corrib gas pipeline ashore to the terminal in North Mayo and then trenching it down to Craughwell in Co Galway to connect with An Bord Gais's national grid is a huge project, warranting armfuls of EISs in glossy ring-binders. The first two get the gas as far as the terminal at Bellanaboy Bridge, about eight kilometres inland. Further tomes will cover the 150-kilometre journey south from the terminal, across rivers, through hedgerows (replantable), and dodging mature trees "wherever possible".

A naturalist's interest begins, however, some 70 kilometres due west of Erris Head and 350 metres down in the Atlantic, where six wells will gather the gas to a central drill-shaft, like the branches of a Christmas tree. Because of the great depth and powerful storms, the central well will be capped on the sea-bed and the wellhead joined directly to the pipeline - all this with the help of Remotely Operated Vehicles (ROVs).

How does one start to think of impact on undersea life? Already, with all the drilling in the field, rock cuttings have been raining down on the seabed and drilling-mud chemicals leaching out into the water - but nothing nature shouldn't make good quite quickly. The same could be expected for the long path of the pipeline, sunk into the sand along with its "umbilical" companion from the terminal (this remotely controls the flow of the wells and sends chemicals to make the gas behave).

Because an EIS is supposed to cover every possible hazard and impact (an undersea blow-out of gas "will rapidly disperse"), its baseline explorations can pile up all sorts of data. Last summer, seabed life was sampled all over the Corrib Field and along the pipeline seabed route. More than 265 different groups of animals were scooped up, many of them unrecorded in Irish waters - more a mark of how little we know, still, of life on the continental slope, than of any particular rarity. At the other end of the scale, the study quotes industry-funded research into undersea whale-calls that finds fin and blue whales (some of the biggest mammals of the deep) passing western Ireland at a peak in winter.

Rather more to the point, as some local observers have pointed out, would be a baseline study of the bottlenose dolphins that actually spend time in Broadhaven Bay, where the terminal effluent will be released at some four kilometres out. This is mainly treated water vapour condensed from the gas, but also occasional overflows of untreated water with traces of chemicals such as magnesium, iron and mercury. While the UK consultants, RSK, sought information from a number of conservation organisations, including BirdWatch Ireland, they seem not to have known of the Irish Whale and Dolphin group, with its special expertise.

At the sands of the Sruwaddacon estuary, the landfall construction scheduled for the autumn threatens to coincide with the arrival of wintering Brent geese and migrant waders such as bar-tailed godwit and curlew. Sruwaddacon is actually a Special Protection Area for birds, within a Special Area of Conservation covering the cliffs and peatlands to the east.

Bringing in diggers, piledrivers and trucks in summer could disturb corncrakes nesting in nearby rushy fields and the little terns, a scarce species, nesting on shingle bars within the inlet. It's also when the salmon and sea trout are passing through to the Glenamoy river and their smolt are leaving for the sea. A construction "window" of August and September, negotiated with Duchas, seems a probably inadequate compromise.

The terminal is destined for the long derelict Glenamoy peatland experimental station, where the site will be scooped out of grassed-over bog within the remnants of a conifer plantation. The plant is a lot bigger than I thought it would be - long and low, with four tall chimneys - but probably not an uninteresting punctuation on the lonely road west from Ceide Fields to Belmullet.

Given the extraordinary spread of buried Neolithic walls, dramatised at Ceide's pyramid, there were obviously possibilities at Glenamoy. But test holes three metres deep, dug under the eye of an archaeologist, have yielded nothing. Local anglers are more concerned with what happens to the vast volume of excavated peat, given the site's proximity to the feeder streams of Carrowmore Lake (itself an SAC).

From the landfall to the terminal, the pipe route sticks mainly to farmland, well away from "sensitive" areas, but its onward journey takes it across a whole series of peatland SACs - Slieve Fyagh Bog, the Bellacorick Bog Complex and the ecologically precious fen at Eskeragh. At this stage, the pipeline will be in the hands of An Bord Gais and following, one hopes, the construction and reinstatement methods on deep peat already worked out between Duchas and Enterprise Energy Ireland (the pipe trench must not, for example, start acting as a long-distance drain).

From the bogs on south, past Lahardaun, Turlough, Manulla and Balla, the "working width" of the 30-inch pipeline (initially, until reinstatement, a gash much like that of a minor road) will push through drumlin country, with its hedges, ringforts and rivers, and afterwards through limestone walls to Craughwell, south of Athenry.

The regional fisheries boards will see it through eight rivers and a dozen streams linked with Carrowmore, Conn and Corrib.

For a project that should virtually vanish into the ground once completed, the impact of bringing Corrib gas to market seems to be under close scrutiny every metre of the way. But the operations at Sruwaddacon Bay, in particular, could expose the folly of compromising on industrial intrusion into a remote and undisturbed estuary granted one of the EU's top badges of protection.