Agriculture Water Balance (AWB) for Jhelum Canal Command Area Using RS and GIS Techniques

Abstract

Agriculture is an important sector of Pakistan Economy which largely depends on water resources, and it is important to define and adopt such agricultural practices that help in understanding the water requirement of crops and its timely supply for effective management of crops and conservation of water resources. Therefore, the current study aims at estimation of agricultural water balance (surplus/deficit) and assessment of Crop Irrigation Requirement under current and future Climate Change Scenario for Upper and Lower Jhelum Canal Command Areas. The required datasets were Sentinel-2 imagery, climatic parameters, CMIP-6 data, and irrigation water supply data. The climatic data and bias corrected CMIP6 data were simulated by employing CROPWAT model and used for the estimation of monthly CWR and CIR for the baseline (1982–2014) and future (years 2024-2048, 2049-2073 and 2074- 2099) period. By using required Irrigation data, water deficit is calculated for current and future scenarios in both canal (UJC and LJC) command areas. Results indicated that Tmax and Tmin showed an upward trend while precipitation showed a downward trend across all scenarios. ETo showed gradual increase and reached to maximum value in May and June. Minimum ET rate was observed in January. The monthly ETo variations suggest that CWR and Irrigation requirements may be highest from April to August and lowest from November to February. However, due to low rainfall and increased minimum and maximum temperature from November to February, Rabi season crop (wheat) faces severe water deficit as compared to Kharif season crops. CWR of all crops is expected to increase in future climatic scenarios which is an indication of amplified crop water demand for all major crops. However, water supply remains constant in both canals. Thus, unmet demand would reach peak values in January, and March-May in future because of comparatively low canal supplies in these months.