270-Irrigated Area Mapping Using Multi-Temporal IRS WiFS Data

Abstract

Irrigated agriculture in many areas of the world is currently being practiced from multiple water sources such as precipitation, canal, wetlands, ground aquifer, etc. This study highlights the use of high temporal remote sensing data (IRS-1 D Wide Field Sensor (WiFS), 188-m resolution) to map landuse/cover along with irrigated classes (canal water, groundwater or wetland irrigated crop) of the rice cropping systems in the 6 Main Canal (6MC) command of Damodar Irrigation Project West Bengal, India for summer season of the year 2000. A multi-date (10 dates 2 bands) image stack was prepared. Using this image stack an unsupervised classification(Fuzzy k-means) backed by Space-Time Spiral Curve (ST-SCs) technique, canal release and wetlands information was used to prepare irrigated classes (canal, groundwater or wetlands) map for summer 2000. ST-SCs have been used to analyze temporal WiFS data to continuously monitor class dynamics over time and space and to determine class separability (different types of irrigated-classes) at various time periods within the season. Results showed that the areas under agriculture, non-agriculture and water were 81%, 18.5% and 0.5%, respectively. While,groundwater, canal water and wetland irrigated rice were 67.6%, 25.6% and 6.8%, respectively out of the agriculture area. Accuracies for the different irrigated classes varied from 85% to 95%. A productivity index (LAI/water-requirement) was also developed and weighed against the observed yield data. Results showed a close agreement between the observed yield and productivity index.