Abstract

The population increase and stride development in ArRiyadh city has triggered water consumption exponentially. Excessive utilization of water for domestic and city services has increased infiltration which in turn has led to water level rise in various parts of the city. Keeping in view, damage to man and environments, various drainage schemes were constructed with the objective to check continuous water level rising. The gravity drainages were designed as consisting of horizontal drains collecting groundwater through gravity action. In this paper, effectiveness of drainage systems in lowering water levels has been experimentally analysed. The investigations consist of drilling monitoring wells, performing permeability tests and flow measurements on existing dewatering pipes. The discharge flow rates were measured using different techniques including Manning's formula. Beside flow measurements, effect of gravity drainage was analyzed through continuous water level monitoring within affected areas.

Key words: Gravity drainage, horizontal drains, discharge flow, manning formula, ArRiyadh, Saudi Arabia.