IAO STREAM FLOOD CONTROL REVISITED

Modifications are being proposed to correct deficiencies in the existing Iao Stream Flood Control Project.The original project, completed in 1981, has experienced extensive erosion, causing undermining and gradual collapse.The U.S. Army Corps of Engineers and the county are conducting an Environmental Assessment to prevent further property damage and reduce flood damage to Wailuku Town.A public meeting to discuss the Draft EA will be held next month.

Image Courtesy: Environet, Inc.

According to the Draft EA, there are several residential and commercial structures along the right bank of the `Iao Stream Channelthat are in danger of being undercut if stream bank erosion continues, as is the heiau along the lower reach of the left bank.The document further states that the erosion caused by high flow events has been partially repaired with concrete rubble masonry, however these repairs have subsequently suffered from additional erosion as well.The DEA states that frequent repairs have proved to be costly and do not adequately address the problem.

New Federal Emergency Management Agency (FEMA) rules require that existing levees obtain certification of their ability to withstand a 100-year frequency flood. A government agency responsible for levee construction or a Registered Professional Engineer must provide this certification. Since the Corps cannot certify the existing project as providing 100-year flood damage reduction in its present condition, the area adjacent the uncertified Iao Stream levees are expected to revert to a flood hazard area in Fall 2009. The proposed project modifications will meet the criteria for future certification by a registered engineer and accreditation by FEMA.

A public meeting to discuss the Draft EA is scheduled for April 2009 at the Velma McWayne Santos Community Center (Wailuku Community Center).Additional information on time and date will be posted at a later date.

(Posted by Wendy OSHER © 2009)