The sampling data from the groundwater quality monitoring network (GQMN) can
not only characterize the properties of the natural resource in groundwater system, but also
delineate contaminated area and risk potential by human activities. This study aimed to provide
a process for designing GQMN for non-existing monitoring well using Nantou area in Taiwan
as the example. First, this study have integrated four contributing factors (land use, soil media,
topography and population) of both vulnerability map and hazard map to calculate the
Contamination Risk Index (CRI) via Geographic Information System (GIS) model. The results
of the map demonstrated that the spatial distribution of the highest contamination risk potential
and provided the preliminary deployment of the spatial locations of the candidate monitoring
wells. According to the deployment of the candidate monitoring wells, this study used the
geostatistical approach to calculate the percentage of the total area with acceptance accuracy of
the candidate monitoring wells for different threshold. Based on the defined performance, the
available monitoring networks for different threshold of three cases are estimated. The
information can support the designer or the decision maker to design appropriate monitoring
network whether they have a limited funding or not.