Cities in arid and semi-arid climatic conditions very often depend on reliable and economic water transmission schemes to import water from distant places. With the first Riyadh Water Transmission System, ILF Consulting Engineers had adopted an innovative design approach by applying a closed hydraulic, high pressure system. This design approach was then further developed taking also advantage of the more recent developments in pipe material and equipment design. In order to reduce the investment and operation costs of water pipeline systems, without compromising safety and erase of operation, the design philosophy has been adopted by ILF to numerous water pipeline systems worldwide, providing the optimized solution for each project.