ESTIMATION OF IRRIGATION WATER REQUIREMENT IN CLIMATE CHANGE SCENARIO FOR BETWA BASIN

Abstract

In this study, assessment of climate change and its impact on irrigation water requirement has been carried out for the Betwa river basin located in Central part of India partially in Madhya Pradesh and Uttar Pradesh. This study has been planned with specific objectives of (1) Evaluation of ETo estimates of two temperature based equations Hargreaves and Blaney- Criddle with the estimates of Penman- Monteith Equation for the Betwa Basin. (2) Trend analysis of weather parameters (Minimum Temperature, Maximum Temperature and Relative Humidity), evapotranspiration and irrigation water requirement. (3) Spatial distribution of crop coefficient (Kc) value using vegetation indices map derived from satellite data. In this study various meteorological data (Temperature, Relative Humidity, Wind Speed, Sunshine Hour and Rainfall) and satellite data were used for the purpose. Field visit of the study area was conducted twice for the purpose of ground truth verification. CROPWAT 8.0 software was used for the estimation of reference evapotranspiration by Penman-Monteith method and effective rainfall. ERDAS Imagine V9.2 was used for the processing the satellite data and generating LULC map and mapping of monthly Kc map from NDVI/SAVI map was carried out in ArcGIS V9.3 software. Correlation analysis of various weather parameters (Minimum Temperature, Maximum Temperature, Mean Temperature and Relative Humidity) has been carried out. Irrigation water requirement of the study area has been estimated using 29 years weather parameter (Minimum Temperature, Maximum Temperature, Mean Temperature and Relative Humidity) and weighed crop coefficient approach. Trend analyses of all climatic variables along with Crop Water Requirement (CWR) and Irrigation Water Requirement (IWR) have been done using Mann-Kendall test and Theil-sen's slope estimator. Finally spatial crop water requirement of the study area was carried out using vegetation indices (SAVI and NDVI) derived from satellite data for Rabi season of the year 2010-I1. Blaney- Criddle equation shows better results than Hargreaves equation when their ETo estimates were compared with Penman-Monteith estimates. Trends of ETo and 1WR were found negative in the Betwa basin. Further GIS based approach revealed that irrigation water requirement in the months from November 2010 to April 2011 were 54.57, 85.74, 74.54, 63.82, 71.62 and 23.14 Mm3 over whole Betwa basin