Less than two weeks after Katrina made landfall, ports along the Gulf coast and channels on the Mississippi River
are once again navigational and safe for ship traffic. The National Oceanic and Atmospheric Administration
, the federal agency responsible for providing the nation’s nautical charts, has played a key role in a major interagency effort to ensure that navigational areas affected by Hurricane Katrina are clear of obstructions and debris.
NOAA led the surveying effort to open the region’s ports and shipping channels as soon as possible, and anticipates all needed surveys will be completed by Saturday. NOAA has survey teams in the Mid-Atlantic pre-positioned to survey shipping channels immediately after Hurricane Ophelia passes.
“Our teams have been working around the clock to help restore safe navigation channels,” said Captain Roger Parsons, NOAA Corps, who is director of NOAA’s Office of Coast Survey. “The currents of the Mississippi River
are so rapid that obstructions that are identified are sometimes washed away before they can be removed, requiring our Navigation Response Teams to go back and resurvey. However, substantial progress has been made, and much of the river and ports have been reopened by the Coast Guard.”
“It requires an immense coordination between the various divisions of NOAA, the U.S. Army Corps of Engineers, U.S. Coast Guard, Navy, local port authorities, state officials and our assets on site to ensure that all critical waterways are clear,” said Parsons.
Beginning August 26 — three days before Katrina hit -- NOAA dispatched NRTs, or Navigation Response Teams, to the Gulf area in preparation for the storm’s aftermath. NOAA deployed four NRTs in the region, along with one hydrographic survey ship (Thomas Jefferson), one coastal oceanography research ship temporarily outfitted with hydrographic survey equipment (Nancy Foster), and a contract hydrographic services provider to scan the sea bottom.
NRTs, which can be quickly dispatched to emergency sites, use small survey launches equipped with side scan sonar to survey waterways for underwater hazards to vessels. When sonar detects an obstruction on the sea bottom, divers determine what it is. Sonar also provides exact water depth over the obstruction. NOAA and contract hydrographic survey ships use both multi-beam and side scan sonar, covering a broader area. Survey launches are also deployed from the ships to cover shallow areas.
Waterways must be surveyed and cleared before oil tankers, cargo ships, and other vessels can safely transit the area. In recent years, ships have gotten longer, wider and deeper, and determining precise water depths is imperative for safe navigation. Hurricanes can play havoc with the sea bottom, rendering the depths and obstructions on nautical charts obsolete.