Assessment of groundwater emergency utilization in Taipei Basin during drought

SummaryBecause of potential impacts of global warming on the occurrence of increasing drought events, this work was to determine locations for groundwater emergency utilization in the Taipei Basin subject to conditions of groundwater quality and quantity. Multivariate indicator kriging was first used to probabilistically define regions with pristine groundwater quality which complies with the drinking water quality standard in Taiwan. Then, the groundwater flow model, MODFLOW, was adopted to simulate groundwater drawdown for specified pumping rates arranged in determined candidate zones with pristine groundwater quality during a six-month drought period. To reduce impacts on land subsidence by pumping, zones of pristine groundwater quality with minimizing pumping drawdown were the optimal locations to extract groundwater for domestic uses. Finally, a feasible scheme of groundwater emergency utilization during drought was proposed based on locations of current water supply plants and land-use. The analyzed results of combining groundwater quality and quantity reveal that two regions, the southern and eastern Taipei Basins, are feasible locations to pump groundwater during drought owing to characteristics of excellent groundwater quality and low pumping drawdown. After considering existent conditions of water supply plants and land-use, the southern Taipei Basin is recommended to extract groundwater for domestic uses, whereas groundwater in the eastern Taipei Basin is only limited for non-drinking purposes.

► Groundwater emergency use in the Taipei Basin is determined during drought.
► MVIK and MODFLOW is used to determine zones based on groundwater quality and quantity.
► Zones of excellent groundwater quality with minimizing drawdown are best locations.
► Groundwater in the southern aquifers is suggested for household uses.
► Groundwater is only limited in non-drinking purposes in the eastern aquifers.