CALLS for an inquiry into the Yenda floods have escalated after the shock discovery of three reports warning the controversial East Mirrool Regulator (EMR) must remain open.
The reports were written between 1979 and 1998 and made it clear the infrastructure played an important role in preventing flooding in the area.
The new information will form part of a class action a group of Yenda residents intend to pursue against Murrumbidgee Irrigation (MI), seeking compensation for damage caused by the March floods.
The members of Yenda Flood Victims Association (YFVA) believe the blocked regulator prevented water from leaving MI's channel system during the floods, causing the inundation of Yenda.
The most recent of the three uncovered reports, the 1998 MIA and Districts Community Land and Water Management Plan, written by a specially-created MIA taskforce, referred specifically to the EMR and infrastructure just outside Barellan.
"These floodways are for the conveyance of flood flows and must remain unobstructed," it read.
Twenty years earlier, a floodplain study written by the NSW Water Resources Commission called for the EMR to stay in use. The MIA branch of the same organisation repeated the warning in a 1991 drainage report.
YFVA president Paul Rossetto expected a hydrology study the group had commissioned to return the same findings.
He hoped the combined information would be enough to convince MI to re-open the structure.
"The whole thing (junction of Mirrool Creek and the main canal) is badly designed now," Mr Rossetto said.
"The EMR needs to be back in operation to prevent Yenda flooding again.
"This needs to be resolved and we need to get some sort of compensation."
As part of its investigations, YFVA has also discovered MI was not the only organisation which made a decision to block the regulator.
The state government's Department of Water Resources blocked two-thirds of the EMR in 1997. MI cemented a further 25 per cent during the latest drought.
YFVA will make a decision on whether to include other organisations in its class action after the hydrology study is completed.