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Item Historical development of irrigated agriculture under the Malaprabha Project, Karnataka, India(Indian Academy of Sciences, 2020) Aswathaiah, U.; Nandagiri, L.The present study analyses the historical development of irrigated agriculture in the command area of the Malaprabha irrigation project located in a semi-arid region of Karnataka, India. Considering the historical period from 1965 to 2014, spatio-temporal changes in irrigated area, cropping patterns, crop and irrigation water requirements using CROPWAT model and sources of irrigation water were characterized relative to the pre-project period at decadal time-step. Overall results indicate an increase in irrigated area, depar-ture from the planned cropping pattern and a shift towards cultivation of water-intensive cash crops, canal releases not conforming to estimated irrigation water requirements and an increase in groundwater-based irrigation in the command area of the project. The findings of this study can be used to formulate more effective management strategies to improve the efficiency of the project and promote sustainable development of natural resources. © 2020. All rights reserved.Item Extraction of Nonlinear Trends in Time Series of Rainfall Using Singular Spectrum Analysis(American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2020) Aswathaiah, U.; Nandagiri, L.Characterization of nonlinear trends in time series of hydroclimatic variables exhibiting nonstationarity is necessary for more realistic projections of climate change and for optimal design of hydraulic structures. The present study was conducted to demonstrate the applicability of a novel Monte-Carlo-based singular spectrum analysis (SSA) to characterize nonlinear trends in historical time series of rainfall characteristics. Long-term (1960-2015) rainfall records for 17 gauges located in the Malaprabha River Basin, India, were used to analyze spatiotemporal variabilities of trends in rainfall totals and number of rainy days for annual and seasonal time periods. While the traditional Sen's Slope and Mann-Kendall (MK) trend tests indicated statistically nonsignificant decreasing monotonic trends at most gauge stations, SSA revealed the existence of steep nonlinear trends and distinct change points in the direction of the trend over the period of record for both rainfall and rainy days. Results of this study demonstrate the potential for SSA to extract crucial information on the trajectories of nonlinear trends and change points in time series of hydroclimatic variables that exhibit nonstationarity. © 2020 American Society of Civil Engineers.