The scheme asked people to take photos at set locations to identify changes in water levels over time.
Douglas Council says it would be "financially irresponsible" to start without flood defences in place.
An internationally important nature reserve in Hampshire is under threat from failing flood defences.
Access to flood defence works sites are being blocked off during this year's Appleby Horse Fair.
Hundreds of homes in the Datchet area saw serious flooding from the River Thames in February 2014.
The project will defend 570 properties on an unprotected stretch of waterfront in Poole town centre.
Planners approve works at Kionslieu Reservoir to reduce the risk of homes being flooded downstream.
At the moment, buildings with fewer than six residents can be converted without planning permission.
Residents say the news is a "massive relief" locally after winter storms damaged the area's sea defences.
