J!15met The Balance of Water - Present and Future moisture laden winds p e.t. pep e.t. p • p = precipitation e = evaporation l.f. = throughflow pe "" percolation e.t. - evapotranspiration Proceedings of AGMET Group (Ireland) and Agricultural Group o/the Royal Meteorological Society (UK) Conference Trinity College Dublin, September 7 - 9, 1994 General Editors: T. Keane and E. Daly Published by the AGMETGroup do Meteorological Service Glasnevin Hill Dublin 9 Copyright © the authors 1994 ISBN 0 95115513 X Cover: Water Balance diagram by kind permission: from Geomorphology and Hydrology by R ] Small, Longman Modular Geography Series Foreword Considerable reliance is placed on climatological and hydrological data for a wide range of water balance studies. The accuracy and archival status of the input data frequently concern hydrologists and agriculturals, who also ask what confidence can be attached to estimates of the different components. Apart from the reliability of instrumentation, the limitations of point measurement or estimation by fonnula, further difficulties arise from the specification of soil characteristics, effects of farming practices, distance from sea, altitude, and indeed from the method of spatialization of the data. This Dublin Conference sets out to review the research and progress of recent decades, address some of the current issues and indicate the likelihood of more accurate specification and determination of the parameters: precipitation, evaporation! evapotranspiration and run-off. The measurement and application of the water balance is central to the study of hydrology. A breath of scholarship together with the most recent research are brought to bear in the following papers presented at the Conference. The AGMET Group, was founded in 1984 to help develop and facilitate the practical application of meteorological services to Irish agriculture and farming. It is composed of experts drawn from the Meteorological Service, Teagasc (Agriculture and Food Development Authority), Geological Survey of Ireland, Office of Public Works, I Veterinary Services, and university departments concerned with agriCUlture, hydrology and the environment. This is the third major conference to be undertaken by the Group. The UK Agricultural Group is one of a number of specialist groups of the Royal Meteorological Society. In the furtherance of the science of agrometeorology it regularly undertakes conferences in Britain on a wide range of related topics. This Conference is the fruit of a unique joint venture between both organizations. T Keane EDaly AGMET Group Coordinator Geological Survey of Ireland Meteorological Service, Dublin 9 Dublin 4 I Acknowledgments Sincerest thanks is expressed to Conference speakers and poster presenters, their parent institutes and the supporting organizations who helped to make this Meeting possible. Bord na Mona, Dr Eugene Bolton and Ms Catherine Meenan are especially thanked for the visit arrangements to their Research Laboratories in Newbridge and for Corporate hospitality. The Organizing Committee wishes to thank the secretaries in the various institutes who typed authors' papers onto disc to a specified format. The continued support of the AGMET Group members has been essential to the success of the Conference. The sustained support of Professor Jim Dooge, who is Chairman of the Conference, is gratefully acknowledged and appreciated. A special thanks to Dr Mike Jones and Ms PameJIa Hennessy, Botany Department, Trinity CoJIege Dublin, for providing the Secretariat to the Conference. Sincere thanks Dr Jerry Clark, Secretary of the Agricultural Group of the Royal Meteorological Society, for his central role in promoting this joint meeting in Britain. Organizing Committee T Bolger, Office of Public Works, Dublin J Clark, University of Nottingham J Collins, University College Dublin E Daly, Geological Survey of Ireland, Dublin I J Dooge, University College Dublin P Hennessy (Conference Secretary), TCD M Jones, Trinity College Dublin T Keane, Meteorological Service, Dublin M McEntee, St Mary's College, Belfast J Martin, Office of Public Works, Dublin I GE.""EROUS SPO;';SORSHIP WAS RECEIVED FRmI: Bord Failte Bord na !\Iona Enyironmental Protection Agency ESB International Geological Suney of Ireland Irish National Committee of HIP Meteorological Service Office of Public Works Tara l\lines Teagasc The British Council I ii PROGRAM~IE Thesday, September 6 Afternoon and evening: arrival of delegates and poster mounting 18.00 Conference registration, Luce Hall 20.00 Reception in Luce Hall, Trinity College Dublin Welcome by Mr Declan Murphy, Director, Meteorological Service; and Mr Liam McCumiskey, Director General, Environmental Protection Agency 1l.\~IILTO:'II BmLD[I;G THEATRE 4 'Vednesday, September 7 09.00 Registration 09.30 Opening of Conference by Mr John Browne TD, Minister for Environmental Protection Conference Chairman: Professor Jim Dooge THE MEASlltE.'!E.';T OF THE WATER BALA..... CE I Morning Chair: Jim Dooge I 09.45 Weighing up the Water Balance John C Rodda, World Meteorological Organization, Genem 10.30 Discussion 10.45 Coffee 11.00 Fifty Years of Potential Evaporation John L Monteith, Institute of Terrestrial Ecology, Edinburgh 11.45 Discussion Chair: Mike Jones 12.00 Poster/Short Presentations 13.00 Lunch 111 Afternoon Chair: John Rodda 14.30 Adequacy of the Irish Rainfall Network Denis L Fitzgerald. Meteorological Service. Dublin 15.10 River flow in Ireland· Characteristics and Measurement John V Martin. Office of Public Horks. Dublin and Con Cunnane. University College Galway 1550 Discussion 16.05 Coffee Chair: Reinder Feddes 16.25 Similarity and Scale Effects in the Water Balance of Heterogeneous Areas I Keith J Beven. CRES. Lancaster University 17.05 Discussion Chair: Mike Jones 17.20 Poster over.iew 18.00 End of Session Thursday, September 8 I 09.00 Depart Dublin for Newbridge. Co Kildare 10.15 Bord na Mona research facilities and corporate presentation I Dr Eugene Bolton. Director of Research Aspects of Blanket Bog Research at Glenamoy William(Billy) Burke,fonnerly An Foras Taluntais. Dublin The Hydrodynamics of Raised Bogs: An Issue for Conservation Donal Daly. Geological Sun:ey of Ireland, Dublin and Paul Johnston. Trinity College Dublin I 12.15 Lunch at B6rd na M6na 13.00 Tour through midland bogs (active and preserved bog/fen) Clara bog. ecology, hydrology, conservation 15.30 Coffee at Clara 19.00 Civic Reception at Mansion House hosted by Rt. Hon. The Lord Mayor, I Councillor John Gormley I iv Friday, September 9 ApPLICATIO:-;S OF WATER BALA."CE Chair: John Monteith 09.30 Water Balance of Wetland Areas Kevin Gilman. Institute of Hydrology. Plynlimon 10.05 Broadleaved Woodland, its Water Use and some Aspects of Water Quality Robin Hall. Institute ofHydrology. Wallingford 10.40 Discussion 11.00 Coffee Chair: Con Cunnane 11.25 Modelling Catchment-scale Water Balance Dynamics using Long Time Series of Rainfall, Stream-flow and Air Temperature Ian G Littlewood. Institute ofHydrology. Wallingford 12.00 Spatial Variability and Accuracy of Remote Sensing Estimates of Evaporation and Soil Moisture "ithin EFEDA '91 Reinder A. Feddes. mzgeningen Agricultllral Unil'ersiry. The Netherlands 12.40 Discussion 13.00 Lunch I Chair: Keith BeYen 14.15 Water: Some Relationships between Quantity and Quality I Marie Shenvood. Environmental Protection Agency. IIbford 14.45 Hydrological and Landuse Changes in North Antrim I Nicholas L Betts. The Queen's Unil'ersiry of Belfast 15.15 Climate Change and a New Water Balance I James C I Dooge. CWRR. Unil'ersiry College Dublin 15.45 Discussion I 16.15 Close of Conference I v PARTICIPANTS A. Abdalla Department of Engineering Hydrology, University College, Galway, Ireland JJ.A. Aherne Environmental Resource Management, Faculty of Agriculture, University College Dublin, Belfield, Dublin 4, Ireland M. Ahsan Department of Engineering Hydrology, University College, Galway, Ireland C.R. Aldwell Geological Survey of Ireland, Beggars Bush, Haddington Road, Dublin 4, Ireland P.E Barba Department of Engineering Hydrology, University College, Galway, Ireland R. Baxter Botany Department, University of Dublin, Trinity College, Dublin 2, Ireland N.L. Betts School of Geosciences, Queens University of Belfast, Belfast Bn I INN, Northern Ireland K. Bevan Department of Environmental Science, Lancaster University, Bailrigg, Lancaster LAI 4Y2, U.K. T. Bolger Office of Public Works, 17/19 Lower Hatch Street, Dublin 2, Ireland G.M. Boyle Environmental Resource Management, Faculty of Agriculture, University College Dublin, Belfield, Dublin 4, Ireland I M. Bruen Civil Engineering Department, University College Dublin, Earlsfon Terrace, Dublin 2, Ireland K. Byrne Environmental Resource Management, Faculty of Agriculture, I University College Dublin, Belfield, Dublin 4, Ireland l.A. Carrick Kildare County Council, Sl Mary's Naas, Co. Kildare, Ireland l.A. Clark Physiology and Environmental Science Department, University of Nottingham, Sutton Bonnington Campus, Loughborough, Leic LEl2 5RD, U.K. I S.L. Clements Department of Engineering Hydrology, University College, Galway, Ireland I l.F. Collins Department of Crop Science, University College Dublin, Belfield, Dublin 4, Ireland I M. Connolly Office of Public Works, 17-19 Lower Hatch Street, Dublin 2, Ireland MJ. Conry Teagasc, Oak Park Research Centre, Carlow, Ireland I P.N. Corish 5 Oaklands Drive, Dublin 6, Ireland C. Coxon Environmental Science Unit, University of Dublin, Trinity College, Dublin 2, Ireland I J.G. Cruickshank