Bathymetric, seismic, geotechnical, oceanographic, numeric model studies made for design of sea outfall line for treated water discharge. Dia. 630mm HDPE pipe is 820 meter long under sea water. Diffuser at -30.m depth. Maximum discharge 550lt/sec. General Method for Sea Outfall ProjectsBathymetric Studies; A number of GPS equipment and an echo-sounder type depth meter have been used to record position versus water depth. Then the data obtained have been used to plot the bathymetric map showing depth versus local coordinates by using special mapping software.3-D Mathematical Model Studies;In order to determine the distribution of the pollutants resulting from the wastewater discharge into sea, three-dimension hydrodynamic models were prepared by using software Telemac3D Version 2.2, developed by Electricitéde France, Département Laboratoire National D