The latest total budget for the repair and upgrade works to meet the standard, 1-in-100-year, flood protection grade was issued by USACE when it also released risk maps detailing protection measures to be in place by 2011.

As a result of the modelling and risk management initiative, USACE said there was an additional cost estimate of US$7.6B – taking the total to almost double, at nearly US$15B. The extra US$7.6B is made up of US$6.3B for improved storm protection, and US$1.3B to enhance interior drainage networks.

While USACE said it had enough funds to proceed until 2009 (fiscal year) with scheduled repairs and improvements, the federal budget process will require the White House to seek the additional funds to complete the works programme within four years. The extra funds will not be needed until about October 2008, it added.

USACE said that the major programme of coastal and river defence works would mean the city has lower residual flood risks than prior to the onslaught of Hurricane Katrina and the failure of parts of the levee system.

The maps were developed by the Interagency Performance Evaluation Taskforce (IPET), which brought a variety of national and foreign agencies, companies and academic experts together to model a system-wide risk assessment. USACE said that the IPET’s work had led to a first in modelling.