Dr. N K Tyagi  played a lead role in conceptualizing, planning   and implementing  research programmes to develop strategies for: 1) conceptualizing and proposing a framework for preventing the development of water logging and salinity through irrigation system improvements, 2) increasing the understanding of  hydrologic  behavior of alkali  soils under reclamation and the technology innovations for  reducing cost  of reclamation 3)   increasing the understanding of the role monsoon rains and subsurface drainage  in promoting use of  salty waters  and modifying    guidelines for use  of these waters in agriculture, 4) hydraulic and economic optimization of groundwater for  establishing the  possibilities of augmenting the water supply through enhanced stream aquifer interaction and 5) increasing the green water use efficiency and improving blue water availability through rainwater management in coastal saline zones in Sundarbans Gangetic delta.  These efforts also involved analyzing the impacts of technological interventions on people and environment and sensitization of development agencies of the dangers of unchecked salinization. This led to formulation and implementation of irrigation system and land rehabilitation programmes and their post rehabilitation monitoring. The outputs and outcomes of each initiative are briefly described.