Author(s): Pattarapong Teerapunyapong; Yutthana Phankamolsil; Areeya Rittima; Yutthana Talaluxmana; Allan Sriratana Tabucanon
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Keywords: Groundwater Recharge; Groundwater Modelling; WetSpass model; Phanom Thuan–Song Phi Nong–Bang Len Operation and Maintenance Projects
Abstract: WetSpass model was applied in this study to simulate and visualize the distribution of groundwater recharge and amount of yearly and seasonal averages groundwater recharge during 2000–2017. The study area covers the Phanom Thuan–Song Phi Nong–Bang Len Operation and Maintenance Projects in western region of Thailand where groundwater has been used as an alternative source of water for irrigation and industrial sectors. The recharge rates performed by WetSpass model were consequently compared with those achieved by empirical relations namely; Chaturvedi Formula (CF), Sehgal Formula (SF), Krishna Rao Formula (KRF), and Bhattacharya Formula (BF). It was exhibited that average rate of yearly groundwater recharge for calibration periods during 2000–2010 was 178.05 mm/yr with RMSE, r2, and d of 48.72 mm, 0.78 and 0.66, respectively. However, average rate of groundwater recharge for validation periods during 2011–2017 was slightly increased which was 186.35 mm/yr with RMSE, r2, and d of 55.09 mm, 0.24 and 0.53, respectively. The simulation result obtained from WetSpass shows that the average annual recharges in the Phanom Thuan, Song Phi Nong, and Bang Len Operation and Maintenance Projects are 22.5%, 22.4%, and 14.8% of average annual rainfall, respectively according to the different soil types. The average groundwater recharges in clay, loam soil, and sandy loam soils are approximately 14.8%, 24.6%, and 25.7% of average annual rainfall, respectively. Moreover, groundwater recharges in dry and wet seasons are quantified as 12.0%, and 88.0% of average annual recharge due to seasonal variation of rainfall magnitudes.
Year: 2020