Hello,
Using the atmosphere-water exchange model has changed since previous tag v7p1r1. You now need to use the water quality module WAQTEL in order to manage it. You can have a look at the heat_exchange example in the examples of TELEMAC-3D, in particular the need to create a WAQTEL steering file and the mandatory keywords in the TELEMAC-3D steering file:
COUPLING WITH = 'WAQTEL'
WAQTEL STEERING FILE = 'name_of_the_waqtel_steering_file.cas'
WATER QUALITY PROCESS = 5
Hope this helps,
Chi-Tuan