Authors:
B. R. Joshi; S. M. Yadav;
Abstract:
The calculation of water consumption for irrigation is critical in maintaining the water supplies for cultivation in tropical catchments. These water withdrawals change seasonally, depending on the rainy and dry seasons. A land-use map is one of the inputs required by hydrological models used to estimate water withdrawals in the basin. However, land-use maps usually offer stagnant details without reflecting the hydrological seasons, associated crop seasons and activities during the year. This research, therefore, assesses the importance of seasonal land-use maps for measuring water withdrawals in the basin. We have developed a crop calendar for the two main seasons (rainy and dry) for the semi-arid Mohgaon basin, Madhya Pradesh, India. Further, two Landsat 8 images from 2016 (March and December) were used to develop seasonal land-use and land-cover
(LULC) maps (March: the non-monsoon season, December: the monsoon season). Classifications for land use were made using 10 land-use and land-cover classes for images from both seasons, which were dependent on the crop calendar. In addition, water withdrawals for irrigation were estimated using LULC maps. There were clear variations in land usage between dry and rainy seasons in rain-fed and irrigated areas. The maximum water withdrawal obtained for irrigating paddy crops was calculated at an average of 800 million m3/year (i.e., 56.2 cm/year). This research concluded that accurate seasonal land-use maps are important for quantifying the annual water use for irrigation in catchment areas with distinct dry and rainy seasons.
Keywords:
Crop calendar, Irrigation, Land-use maps, Water withdrawal.