Mr. Wm. Rossasked the Secretary of State for Northern Ireland when he expects the programme of flow gauging stations for Lough Neagh to be completed; how many are now in operation and how many more are needed.
§ Mr. Dunn, pursuant to his reply [Official Report, 17th April 1978], gave the following information:
Of the 19 flow gauging stations within the Lough Neagh catchment recommended by the Lough Neagh working group all but two are operational, of which the construction of one is delayed because of land acquisition problems. The need for the second station is being reassessed in the light of the overall Northern Ireland hydrometric programme.
Mr. Wm. Rossasked the Secretary of State for Northern Ireland what would be the effect on the level of Lough Neagh of one inch of rain in the catchment area, if the rainfall in a 24 hour period and the outflow was at its maximum during that period and for 24 hours and 48 hours thereafter.
§ Mr. Dunn, pursuant to his reply [Official Report, 17th April 1978], gave the following information:
It is not possible to provide a comprehensive answer to this question, since the effect on the level of Lough Neagh of one inch of rain in the cathcment area will depend on the run-off, which is influenced by many factors including the existing wetness of the catchment and the seasonal effects of cropping and temperature. One inch of run-off is equivalent to a depth of approximately 12 in over the lough. The maximum recorded outflow, over the past five years, for a period of 24 hours is equivalent to a depth of approximately 3 in in the surface of the lough.
Mr. Wm. Rossasked the Secretary of State for Northern Ireland what is the catchment area for Lough Neagh, in square miles and how much of this is in Northern Ireland and how much is in the Irish Republic.
§ Mr. Dunn, pursuant to his reply [Official Report, 17th April 1978], gave the following information:
697WThe catchment area of Lough Neagh, including the lough area of 149 square miles, is 1,874 square miles, of which 156 square miles is in the Irish Republic.
Mr. Wm. Rossasked the Secretary of State for Northern Ireland how many acres of arable land surrounding Lough Neagh would be flooded if the level of the Lough were to rise to 51 ft., to 51 ft. 6 in., 52 ft., 52 ft. 6in., and 53 ft.
§ Mr. Dunn, pursuant to his reply [Official Report, 17th April 1978], gave the following information:
It is not possible from the survey information available to provide an answer in the form requested. However, survey information indicates that approximately 2,000 acres of land is exposed on the shore of Lough Neagh by lowering the level of Lough Neagh from 52.0 ft. to 50.0 ft. This does not take account of the more widespread drainage effects of 698W such lowering, and the Lough Neagh working group reported that the 1959 lowering of the lough
resulted in extensive improvement to an assessed area of some 28,000 acres of land adjacent to Lough Neagh and the lower sections of the inflowing rivers".
Mr. Wm. Rossasked the Secretary of State for Northern Ireland how many millions of gallons of water are needed to raise the level of Lough Neagh one inch: and how many days maximum outflow this represents.
§ Mr. Dunn, pursuant to his reply [Official Report, 17th April 1978], gave the following information:
About 2,100 million gallons of water are required to raise the level of Lough Neagh by one inch. This is equivalent to the maximum outflow recorded during the past five years, persisting for a period of about nine hours.