Environmental impact of Karkheh Dam in the southern part of Iran on groundwater quality by intervention and trend analys
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Environmental impact of Karkheh Dam in the southern part of Iran on groundwater quality by intervention and trend analysis Mohammad Sakizadeh
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Lloyd H. C. Chua
Received: 29 March 2019 / Accepted: 24 September 2020 # Springer Nature Switzerland AG 2020
Abstract The main objective of this research was to investigate the impact of the construction of Karkheh Dam in 2001 (referred to as the intervention time), on groundwater quality. The time series of total dissolved solids (TDS) and other water quality data including potassium (K+), sodium (Na+), magnesium (Mg2+), calcium (Ca2+), bicarbonate (HCO3−), sulfate (SO42−), and chloride (Cl−) for the period between 1996 and 2012 were analyzed. The magnitude of the trend by Sen’s slope estimator for HCO3−, SO42−, and TDS was 0.005, − 0.02 and − 3.04, where a decline expected for SO42− and TDS, whereas for HCO3−, an increase was expected. According to the Pettitt’s test, the mean of TDS decreased from 2306.9 mg/l between 1996 and 2002 to 797.2 mg/l between 2002 and 2012. During this time, the standard deviation of TDS declined from 2187.1 to 132.0 mg/l. The results of change point detection by the Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10661-020-08629-z) contains supplementary material, which is available to authorized users. M. Sakizadeh (*) Environmental Engineering and Management Research Group, Ton Duc Thang University, Ho Chi Minh City, Vietnam e-mail: [email protected] M. Sakizadeh Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam L. H. C. Chua School of Engineering, Faculty of Science Engineering & Built Environment, Deakin University, 75 Pigdons Road, Waurn Ponds, VIC 3220, Australia
Pruned Exact Linear Time (PELT) algorithm were consistent with that of Pettitt’s test providing confirmation that a change point in Ca2+, Mg2+, SO42−, and TDS time series data occurred in 2002.The findings from intervention analysis using the Bayesian structural time series (BSTS) technique showed that TDS concentration during the post-intervention period had an average value of 1127 mg/l compared with 1972 mg/l, before the dam construction. The time series of TDS demonstrated a decrease of about 43% following the intervention time. Keywords BSTS . Change point detection . Intervention analysis . PELT algorithm . Pettitt’s test
Introduction An important objective in environmental monitoring programs is to detect the temporal trends in parameters of interest. A number of statistical procedures have been developed by researchers to distinguish between random fluctuations and persistent changes in data caused by perturbations in the environment (Libiseller and Grimvall 2002). Both parametric and non-parametric methods have been utilized for this purpose. Among the parametric methods, locally weighted regression (Huang et al. 2017) has been widely applied in water quality studies. On the contrary, non-parametric techniques are more popular, and the application of nonparametr
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