Before and during landfall, water poured into the Bay of St. Louis, and the initial flooding occurred in low-lying areas along the Jourdan River and its tributary bayous. Therefore, Diamondhead and Kiln began to flood before the bulk of the surge came. A record storm surge of nearly caused extensive damage. Many homes were badly damaged or completely destroyed, especially those homes on the south side of Diamondhead, facing the Bay of Saint Louis. The commercial center, including stores and restaurants, was mostly destroyed. A 1,000-gallon aviation fuel tank from the airport in Diamondhead floated onto I-10. The north side fared better, and many of the people whose homes had been destroyed in neighboring cities, as well as in Diamondhead, moved into the houses which remained on the north side. Overnight, the population swelled from 6,500 to 9,000. Following Hurricane Katrina, the POA found itself facing issues that it had not anticipated that brought back the issue regarding incorporation. A city would be eligible for federal or state financial resources that the POA would not have access to as a private entity. Concerns about the expiration of the various covenants that governed different areas within the POA also created anxiety among homeowners. In July 2006, the POA commissioned a study to determine how to best protect its assets. The study ultimately determined that incorporation would be the best route. In 2009, a petition supported by the Property Owners Association (POA) to hold an incorporation election was filed with the Hancock Chancery Court, and an election approved the incorporation. Opponents contended that the petition lacked a sufficient number of signatures and that incorporation requirements were not complied with. In 2010, the Hancock Chancery Court ruled against the opponents, who then appealed to the Supreme Court of Mississippi. The appeal further claimed irregularities during the hearing on the original objection. On October 29, 2011, the Supreme Court of Mississippi upheld the Hancock Chancery Court and ruled against the irregularity claims. In January 2012, a motion for extension to appeal the decision was denied by the Supreme Court, and a final edict mandating the incorporation was issued. The City of Diamondhead was presented its charter as the 111th city in Mississippi by Secretary of State Delbert Hosemann on February 6, 2012. Unlike most of the Mississippi Gulf Coast, which is relatively level, the Diamondhead area has more rolling topography, with elevations ranging from sea level to over . The city is bordered to the south by the Bay of Saint Louis.