Assessment of shallow groundwater use for irrigating park trees in the metropolitan Taipei Basin according to variability conditions of water quality

Abstract

Shallow groundwater extraction for irrigating park trees in the Taipei Basin is a sustainable solution for environmental resource management and urban landscape preservation because it reduces the potential for damage to the underground infrastructure caused by rising groundwater levels. This study identified appropriate locations with clean and stable groundwater for irrigating park trees in the metropolitan Taipei Basin according to variability conditions of water quality. First, six hydrochemical parameters of groundwater associated with the Taiwan irrigation water quality standard were collected from a 12-year Taiwan Environmental Protection Administration survey. The first, second, and third quartiles of the six hydrochemical parameters were obtained to establish three estimation thresholds. According to the irrigation water quality standard, multivariate indicator kriging (MVIK) was adopted to probabilistically evaluate the integration of the six hydrochemical parameters. Subsequently, entropy based on the MVIK estimates was applied to quantify the spatial and seasonal variability of the hydrochemical parameters. Finally, the locations with high estimated probabilities and low local uncertainties were identified as appropriate locations for extracting groundwater to irrigate park trees. The results revealed that MVIK and entropy can be combined to determine the variability conditions of groundwater quality parameters and identify parks suitable for extracting groundwater for irrigation. Keywords: Groundwater, Irrigation, Park, Variability, Multivariate indicator kriging (MVIK), Entropy