Gangua nallah, a stream originate from the western upland area of Bhubaneswar city (Chandaka Reserve Forest area) and flows along the south eastern side of the city almost parallel to Daya river along city-side and ultimately outfalls into Daya river near village Vadimula of Khurdha district in the state of Odisha. The total length of Gangua nallah from its origin to the confluence point is approximately 45 Km. After traversing along the city side, Gangua nallah confluences with Daya river approximately 9 km towards south direction from the city limit.
Gangua nallah flows along the city side of Capital city of Bhubaneswar. The city does not have any organised sewage treatment system and the sewage is discharged through storm water drains. There are about ten numbers of storm water drains in the city that carry untreated waste water and outfall into Gangua nallah at different locations. Thus Gangua nallah receives untreated sewage of the capital city and hence is polluted by the discharge of municipal waste water of the city only through several storm water drains.
After traversing a distance of 13 Km from its origin, Gangua nallah starts receiving wastewater of the city through storm water drains at different points. Hence, the polluted stretch of Gangua nallah covers a distance of about 32 Km. There is an average flow of 1.17 meter/ second throughout the stretch of the Gangua nallah. After receiving the wastewater of the city of Bhubaneswar, through storm-water drains, Gangua nallah has become a waste water carrying nallah and there are no beneficial uses of its water till its confluence with Daya river.