Hydrological Study & Design of Hydraulic Structures for Lake Purification in NUST Campus

Abstract

Water pollution has become a serious problem worldwide, especially for lakes with a large stagnant water body. Islamabad, the capital of Pakistan, has seen rapid growth in population throughout the years (estimated at 1.23 million in 2023 by UN World Urbanization Prospects), thereby leading to increasing demands on natural resources and causing adverse effects on the environment like extensive pollution of surface water and of ground water by improperly disposed solid waste. This project aims to conduct hydrological studies on the streams flowing into NUST Lake, situated in Sector H-12, Islamabad, Pakistan. The main objective is to design hydraulic structures that will mitigate the pollution caused by polluted streams flowing into the lake. To achieve this goal, the proposed methodology utilizes several hydrological techniques, survey equipment, and software to gather relevant hydrological parameters needed for the design of the hydraulic structures. The proposed solution involves stopping the flow of low discharge streams (high in pollution concentration) from entering the lakes whilst granting entry to high discharge streams (low in pollution concentration). This will be achieved using hydraulic structures including an ogee-crested weir, channel walls, impervious apron, sewage pipes, and a concrete-lined trapezoidal channel. The ogee-crested weir will allow high discharge streams to enter the lakes and divert low discharge streams into the sewage pipes which will in turn transport them into a concrete-lined trapezoidal canal that will discharge the flows in an area away from the lakes. Laboratory tests have also been performed to confirm our theories of flows in the rainy season (high discharge streams) generally containing less pollution than flows in the dry season (low discharge streams) and to determine the coefficient of discharge over ogee-crested weirs. To ensure the effectiveness of the proposed solution, it has been designed against peak flows.