Field survey and modelling of irrigation water quality indices in a Mediterranean island catchment: a comparison between spatial interpolation methods |
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Authors: | Nikolaos Malamos Demetris Koutsoyiannis |
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Institution: | 1. Department of Agricultural Technology, Technological Educational Institute of Western Greece, Amaliada, Greecenmalamos@teiwest.gr;3. Department of Water Resources and Environmental Engineering, School of Civil Engineering, National Technical University of Athens, Zographou, Greece |
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Abstract: | ABSTRACTA biannual survey of physico-chemical quality indices of 104 irrigation-water wells located in a cultivated plain of a Mediterranean island catchment was conducted using a multi-parameter probe. The campaign was planned so as to differentiate between the dry and wet seasons. The acquired data constituted the test bed for evaluating the results and the features of four spatial interpolation methods, i.e. ordinary kriging, universal kriging, inverse distance weighted and nearest neighbours, against those of the recently introduced bilinear surface smoothing (BSS). In several cases, BSS outperformed the other interpolation methods, especially during the two-fold cross-validation procedure. The study emphasizes the fact that both in situ measurements and good mathematical techniques for studying the spatial distribution of water quality indices are pivotal to agricultural practice management. In the specific case studied, the spatio-temporal variability of water quality parameters and the need for monitoring were evident, as low irrigation water quality was encountered throughout the study area. |
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Keywords: | irrigation water quality specific conductance pH spatial interpolation bilinear surface smoothing kriging inverse distance weighted nearest neighbours cross-validation |
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