By Tim Gaynor and Matthew Bigg New Orleans Sept. 1: Hurricane Gustav barged ashore on the US Gulf Coast west of New Orleans on Monday, hammering the city devastated by Katrina in 2005 with surging floodwaters that threatened its rebuilt levees. The storm was weaker than feared. But waves splashed over floodwalls containing the New Orleans industrial canal, triggering a tense watch over the barrier system that failed three years ago. Water rose in the Fifth District, west of the canal, and the US Army prepared to evacuate residents who stayed behind. Nearly two million people fled the Gulf Coast, and over 11 million residents in five US states were threatened. The streets of New Orleans were ghostly quiet after 95 per cent of its population fled, responding to desperate evacuation calls, leaving only 10,000 people behind. New Orleans mayor Ray Nagin cautioned residents against too much early optimism, expressing concern about the stability of the concrete and earthen flood barriers. Gustav also took centrestage in US politics. The Republicans were to open their convention on Monday to nominate presidential candidate John McCain with a bare-bones programme stripped of the usual pomp. Gustav had stirred uneasy comparisons to Katrina, the costliest hurricane in US history, which killed some 1,500 people. President George W. Bush, heavily criticised for the slow Katrina relief efforts, cancelled his appearance at the Republican convention and travelled to Texas to oversee emergency efforts. "This storm has yet to pass. It