Assessment of Stormwater Quality in the Context of Traffic Congestion: A Case Study in Egypt

Abstract

The aim of this study was to investigate the effect of traffic congestion in urbanized areas (parking lots and highways) on stormwater quality. Three separate locations in Egypt’s heavily urbanized and populous Giza Governorate were picked for the purpose of monitoring and evaluating the stormwater quality: Faisal (A), El Dokki (B), and Hadayek El-Ahram (C), with catchment areas of 10,476, 7566, and 9870 m2, and with monthly average daily traffic (MADT) values of 47,950, 20,919, and 27,064 cars, respectively. The physio-chemical and heavy metal stormwater quality parameters of six water samples were investigated and compared with Egypt’s water criteria and the World Health Organization (WHO) guidelines. The water quality index (WQI) and the irrigation water quality indices were used to assess the uses of stormwater. The results showed that the WQI varied from 426 to 929, with an average of (661 ± 168), indicating that the stormwater was contaminated at each location under examination and needed pretreatment in order to be useful. As a result, the allowed stormwater quality standards were exceeded for heavy metals such as Al, Cr, Cd, Fe, and Cu. The indicators of the stormwater quality for irrigation—the total dissolved solids (TDS), sodium adsorption ratio (SAR), soluble sodium percentage (SSP), permeability index (PI), magnesium adsorption ratio (MAR), and Kelley’s ratio (KR)—show excellent stormwater for irrigation, while the total hardness (TH) and residual sodium bicarbonate (RSBC) indicate poor irrigation water quality. It is advised to sweep the streets to remove particle-bound pollution before it reaches storm drain water, and to put in place an adequate stormwater sewerage system to catch rainwater.