Ma, J., 2020. Consideration of the allowable groundwater discharge in a tunnel project. In: Hu, C. and Cai, M. (eds.), Geo-informatics and Oceanography. Journal of Coastal Research, Special Issue No. 105, pp. 110–114. Coconut Creek (Florida), ISSN 0749-0208.

Alteration to the groundwater flow system during tunneling may be irrecoverable, such as due to excessive discharge-induced groundwater table drawdown and impact to the regional ecological environment. It is therefore necessary and beneficial to specify allowable groundwater discharge during the planning and design of a tunnel project. A case history for a project during which the groundwater was mismanaged in the tunnel design and construction shows the difficulty of coping with the situation in an environmentally and operationally favorable way, especially for sections with a high-permeability belt or layer in the surrounding rocks. To drain groundwater in a controlled mode in a tunnel project, it is vital to specify the allowable discharge in the tunnel design and to control the groundwater drainage magnitude during construction and operation.