The paper presents the concept and deployment of the agro-hydro-meteorological monitoring system (abbrev. AgHMM) created for the purposes of operational planning of regulated drainage and irrigation on the scale of a drainage/irrigation system (INOMEL project). Monitoring system involved regular daily (weekly readings) measurements of agrometeorological and hydrological parameters in water courses at melioration object during vegetation seasons. The measurement results enable an assessment of the meteorological conditions, moisture changes in the 0-60 cm soil profile, fluctuations of groundwater levels at quarters and testing points, also water levels in ditches and at dam structures, and water flow in water courses. These data were supplemended by 7-day meteorological forecast parameter predictions, served as input data for a model of operational planning of drainage and subirrigation at the six melioration systems in Poland. In addition, it was carried out irregular remote sensing observations of plant condition, water consumption by plants and soil moisture levels using imagery taken by unmanned aerial vehicles and Sentinel’s satellites. All the collected data was used for support operational activities aimed at maintaining optimal soil moisture for plant growth and should to provide farmers with high and stable yields. An example of the practical operations using the AgHMM system in 2019 is shown on the basis of the subirrigation object at permanent grasslands located in central Poland called “Czarny Rów B1”.