Already fish, including including pike, tench, carp, roach and an eel, have been moved from the lake and released into the Nene in preparation for the work to start.
The lake will now be pumped dry and the silt will be removed before work can start on construction which is being handled by the Environment Agency on behalf of the Becket's Park Partnership.
When complete, there will be 80 berths, six of which will be residential.