Bathymetric, seismic, geotechnical, oceanographic, numeric model studies made for design of sea outfall line for treated water discharge. Dia.710mm HDPE pipe is 1120 meter long under sea water. Diffuser at -30.m depth. Maximum discharge 800 lt/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 bathimetric 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