The Mississippi river delta of the US state of Louisiana is a landscape still reeling from Hurricane Katrina, and facing the threat of worse storms to come.<br /><br />The fragile wetlands of the Mississippi delta once provided sufficient shelter from the storms of the Gulf for humans and wildlife. <br /><br />But when Katrina devastated the city of New Orleans four years ago, it changed the natural and cultural landscape of the region. And since then, people have been leaving.<br /><br />Al Jazeera's Nick Clark reports from New Orleans - for the latest in our special series on Rivers Under Threat.
