Irrigation Drainage 25 Management 15 Congresses 14 Water-supply 14 Water resources development 12 Economic aspects 11 Agriculture 8 History 8 Irrigation farming 8 Research 8 Economic conditions 5 Irrigation engineering 5 Periodicals 5 Reclamation of land 5 Irrigation canals and flumes 4 Irrigation efficiency 4 Water conservation 4 Water-supply, Agricultural 4 Bibliography 3 Costs 3 Flood control 3 Forest management 3 Public works 3 Rice 3 Social conditions 3 Soils 3 Agriculture and state 2 Canals 2 Case studies 2