Confined Groundwater at No . 52 , Hollywood Road , Hong Kong

Two standpipes were installed for site investigation purposes at No. 52, Hollywood Road, Hong Kong. Groundwater was observed to overflow continuously from the standpipes. After pipes were added to the top of the standpipes, the water level in the standpipes rose up to 0.6 and 3.7 m above the ground surface, respectively. This indicates that the groundwater in this site is well confined. Chemical analysis of the water samples from the standpipes confirms that the water was from deep groundwater. A further examination of the borehole and piezometric information collected from various sources indicates that the overflow phenomenon is quite common in Sheung Wan and Mid-Levels areas. This observation provides convincing field evidence for the conceptual model proposed by Jiao and Nandy [1] concerning a confined groundwater zone in slopes of weathered igneous rocks in Hong Kong. It is suggested that overflow is an important hydrogeological feature and deserves careful investigation since it may have adverse impact on slope stability and foundation design.