English to Arabic Tech/Engineering Construction / Civil Engineering

Between Gate (1) and Gate (2), they have executed one manhole which collects grey water from two pipes (inlet pipes 300 mm) and one pipe go out (outlet pipe 200 mm), in such case the outlet pipe diameter must be larger than the inlet pipe diameter (at least 400 mm), but they install 200 mm diameter pipe (you can make sure from the existed manhole on the main network), (They tried to cheat you by fixing a small piece of pipe at the beginning of the outlet pipe) (demonstrative drawing attached).