The Saq aquifer represents one of the major groundwater sources
in Saudi Arabia. The study area constitutes the northwestern part of Saudi
Arabia that includes major cities from Qassim and Hail in the east to Al-
Jouf in the north, Tabuk in the northwest and Al-Madinah Al-Monawarah
in the southwestern part.
The analysis of hydraulic parameters of ground water shows that
the regional flow system is directed towards the northwest. Statistical
analysis of groundwater was carried out using scatter plots, correlation,
cluster, principle components, and factor analysis. The results of
analyzing data by these techniques indicated the presence of strong
relation between sodium, calcium, chloride, Electrical Conductivity and
Total Dissolved Solids. Two main clusters were identified and these
clusters were divided into six subgroups. Further classification by
principal component and factor analysis, shows three factors responsible
for the variations in groundwater quality of the Saq aquifer.