Indian scientists from the Civil Engineering Department, Indian Institute of Technology, Gandhinagar, Gujarat has developed the high-resolution maps of irrigated areas of India from 2000-2015.
This have been prepared using remote sensing data. The maps were validated with ground-based survey data. High-resolution irrigated water maps are essential for estimation of irrigation water demand and consumption on a spatial scale, crop productivity assessments and hydrologic modelling.
Scientists used the remote sensed vegetation index data from MODIS [Moderate Resolution Imaging Spectroradiometer] and high resolution (56 metre) land use/land cover data from the National Remote Sensing Center (NRSC) to prepare the maps.
Also, the resolution of remotely sensed vegetation index data may not be able to fully capture irrigated areas of small land holdings in India. And, a 250-metre pixel is considered fully irrigated even if there is partial irrigation in a small field within a pixel.
To highlight the trend and response of irrigation to rainfall variations, the authors chose the Indo-Gangetic Plain, which had witnessed severe drought in 2002 and 2015. To understand how unusual the 2015 drought was, the authors looked at the magnitude of deficit in 2015 monsoon rainfall and also looked at the long-time data from IMD.
Why New Irrigation Map?
The irrigation maps developed by the Food and Agriculture Organisation (FAO) are of low resolution, the high-resolution maps of International Water Management Institute (IWMI) are available for just one year and do not cover the entire country.