Characterizing Urban Storm Runoff Quality in Dhahran City in Saudi Arabia

The need to increase the water supply of the Kingdom of Saudi Arabia to keep up with the industrial and agricultural development cannot be overemphasized. Several ways exist to enhance the available supplies. One such method is the utilization of storm runoff from urban areas after appropriate treatment. In this study, the possibility of using urban runoff for industrial, irrigation, and other municipal uses after appropriate treatment is investigated. To achieve this, a representative urban watershed in the city of Dhahran was used and the runoff quantity and quality were determined over a four-year study period. The quality parameters considered were suspended solids (SS), total dissolved solids (TDS), alkalinity, hardness, chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), nitrite plus nitrate, phosphorous (P), chlorine (Cl), sulfate, grease and oil, coliforms, and heavy metals. The data obtained on the quantity and quality of the runoff in this city were further analyzed and the levels of treatment required for the various types of uses have been determined. The study showed that SS, COD, and coliforms were the major pollutants. Accordingly, the most feasible alternative is to convert the storm-drainage network to a sedimentation and temporary storage reservoir. If disinfected, the runoff water can be used for restricted irrigation.