Seawater reverse osmosis desalination systems produce brine (concentrate) that normally must be discharged back to the sea. The concentrate can have up to twice the salinity of the feedwater and can cause environmental impacts to the marine environment. Innovation in the design and evaluation of diffuser systems has led to reductions in potential environmental impacts by causing rapid dispersion of the high salinity plume. The nearfield and farfield models used to assess potential environmental impacts of the dense water discharge have also been improved to allow assessment of impacts and to make design changes that lessen them. The selection of discharge sites has been improved by the ability of obtaining rapid and accurate bathymetric and water quality data that can be used in models to assess circulation and other aspects of outfall design and to monitor and assess potential discharge impacts.