Adisorn Champathong, Naota Hanasaki, Masashi Kiguchi, Taikan Oki
Received 2020/01/10, Accepted 2020/04/06, Published 2020/06/17

Adisorn Champathong¹⁾, Naota Hanasaki²⁾, Masashi Kiguchi³⁾, Taikan Oki³⁾⁴⁾

1) Royal Irrigation Department, Bangkok, Thailand
2) National Institute for Environmental Studies, Ibaraki, Japan
3) Institute of Industrial Science, The University of Tokyo, Tokyo, Japan
4) United Nations University, Tokyo, Japan

Understanding the extent to which human activities affect river flow is fundamental for enhancing effective water resources management. In past decades, various methods have been proposed to estimate naturalized flow (i.e. the expected flow if the basin is unaffected by human activities). However, there are still drawbacks to naturalized flow estimation, particularly in a highly regulated basin with incomplete hydrological observation. This study proposes a method for daily naturalized flow development at the key station of the Chao Phraya River Basin; the most highly regulated basin in Thailand. The naturalized flow is estimated by applying the Naturalization with Coarse and Fine Components (NCFC) method to perceive river flow conditions unaffected by human disturbance. The estimation is derived with the integration of five components: (1) observed river flow at the key hydrological station; (2) changes in major reservoir storage; (3) water withdrawal along the river; (4) travel time from major reservoirs to the station; and (5) the filtering technique used by Savitzky-Golay with a three-day window.

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Copyright (c) 2020 The Author(s) CC-BY 4.0