Browsing by Author "Hiremath, C.G."

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    Regionalization of flow duration curves for catchments in southern India using a hierarchical cluster approach
    (IWA Publishing, 2023) Hiremath, C.G.; Nandagiri, L.
    The present study on the hydrologic regionalization was taken up to evaluate the utility of hierarchical cluster analysis for the delineation of hydrologically homogeneous regions and multiple linear regression (MLR) models for information transfer to derive flow duration curve (FDC) in ungauged basins. For this purpose, 50 catchments with largely unregulated flows located in South India were identified and a dataset of historical streamflow records and 16 catchment attributes was created. Using selected catchment attributes, three hydrologically homogenous regions were delineated using a hierarchical agglomerative cluster approach, and nine flow quantiles (10–90%) for each of the catchments in the respective clusters was derived. Regionalization approach was then adopted, whereby using step-wise regression, flow quantiles were related with readily derived basin-physical characteristics through MLR models. Cluster-wise performance analysis of the developed models indicated excellent performance with an average coefficient of determination (R2) values of 0.85, 0.97, and 0.8 for Cluster-1,-2, and-3, respectively, in comparison to poor performance when all 50 stations were considered to be in a single region. However, Jackknife cross-validation showed mixed performances with regard to the reliability of developed models with performance being good for high-flow quantiles and poor for low-flow quantiles. © 2023 The Authors.
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    Regionalization of Flow Duration Curves for West Flowing Rivers of India
    (Springer Science and Business Media Deutschland GmbH, 2022) Hiremath, C.G.; Nandagiri, L.
    A flow duration curve (FDC) by providing a concise description of the temporal variability of streamflow from a river basin is extremely useful as a hydrological signature and also in the design of water resources projects. However, long-term historical measured streamflow records are essential to derive the FDC, and hence, a major challenge has been to develop methods to estimate the FDC for ungauged river basins. Also, for the derived FDC to provide an accurate representation of the variability of natural flows, no regulations/abstractions must exist upstream of the gauging station. Therefore, the present study was being taken up to develop a methodology for prediction of FDCs in ungauged river basins located in the hydrologically homogeneous West flowing rivers of India using streamflow records of 14 unregulated river basins. FDCs were derived for each basin using frequency analysis, and flow quantiles at specific exceedance probabilities were extracted. Subsequently, the regionalization approach involving transfer of hydrological information from gauged basins to ungauged basins was adopted by developing regression models relating flow quantiles to easily derived basin physical characteristics. The performance of the developed regression models was evaluated using validation datasets and found to yield satisfactory results. Results of this study will permit estimation of flow quantiles and FDCs in ungauged basins located within West flowing rivers of India. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.