Abstract
Excessive water usage together with limited capacity of local hydrogeological environment to dispose excess water or waste water has emerged as a problem of water level rise in many parts of ArRiyadh, the capital city of Saudi Arabia. In the past, groundwater rise to shallow horizons has caused considerable impact on public health, environment and infrastructure. In order to reduce and maintain groundwater to safe level, ArRiyadh Development Authority has constructed a gravity drainage system in the affected areas. During the initiation of the gravity drain project, water level in eastern ArRiyadh was > 15 m; therefore, the area was not included in the project but was subjected to regular groundwater monitoring. During the recent decade, eastern ArRiyadh has witnessed quick water level rise, with an average rate of 0.55 m/year. This water level rising trend seems persistent with time which may impart serious damage to the environment and infrastructure. The study shows that the presence of thick clays within eastern alluvium retards hydrodynamic connectivity and inhibits vertical groundwater movement.