The project includes linking the sewage plants Manfouha STP and Al-Ha'ir STP in Riyadh in order to transfer water to the sewage plants in Al-Ha'ir. This is done through the implementation of an integrated project that includes underground tunnels with a diameter of 3,300 mm and a total length of 11,755 linear meters, where the effect of wastewater on valleys and areas adjacent to the sewage line was taken into account through odors or sewage leakage, as the project is a qualitative leap. This will address many environmental problems in the city of Riyadh. An advanced methodology has been introduced to reduce the impact on valleys and the environment and to benefit from treated water and invest it in the future