DESIGN OF FOURTH DAM IN NUST AND ANALYSIS OF ITS EFFECT ON NEARBY BUILDINGS

Abstract

Pumping ground water by means of tube wells is a popular way of meeting water requirement but it runs the risk of lowering the water table thus causing water scarcity. Sector H-12, Islamabad, employed the same technique to fulfill the water demands of the university and after sometime the tube wells became dry. A successful attempt to raise the water table was made via construction of a series of small earthen dams. As an insurance, a fourth dam is proposed upstream of the third dam. The dam is located behind the Ghazali Hostels and the squash court. A topographic map of the site was developed after performing a detailed survey of the site. Samples were collected from 5 boreholes and the soil properties were discovered by means of various field and lab tests. Hydrological analysis of the site provided the catchment area size i.e. 1.96 km2 and the reservoir capacity of approximately 9500 cubic meters. With abundant sandy lean clay available near the site, a homogenous dam has been designed with the crest level as high as 20 feet above the ground level. Analyses have been carried out to ensure safety in terms of slope stability, seepage and rapid drawdown. Taking into account the present water table depth and expected increase due to proposed dam, it has been made sure that the nearby buildings do not suffer with any ill effects. The dam economically and efficiently serves its purpose in the long run ensuring self-sustainability of NUST in terms of water requirement.