The Defence of Hamburg

Initial decoy methods in and around Hamburg included the disguising of the distintive lakes in the centre of the city.
The intention was that bombers using the Binnenalster as an aiming point would drop their bombs harmlessly into the watery decoy. 

The inaccuracy of British bombing meant this deception was ineffective and after a short period it was no longer maintained.

The German also created a decoy lake at Wedel to resemble the famous Außen Alster near the Hamburg city centre.
The Allied Operational Research Section believed that, "the whole of the village of Wedel has been made into a decoy for Hamburg which it resembles somewhat in shape".
 

There is no record as to what the citizens of Wedel thought of this deception as it is believed to have fooled a large proportion of bombers on the night of March 3rd 1943.......a significant raid before Operation Gomorrah in July/August 1943.



The description of the raid explains the successful deception (extract courtesy of Bomber Command Diaries)

With the development of H2S and Pathfinder marking techniques such physical decoy systems were abandoned.
However, fire sites and decoy target indicators continued to be employed.