Mobile Bay Blog

Dauphin Island needs beach renourishment to protect Coden, Bayou La Batre, and Seafood Industry

October 24th, 2008 8:42 AM

Dauphin Island officials hope to fix east end erosion

Friday, October 24, 2008

By KATHERINE SAYRE

Staff Reporter

DAUPHIN ISLAND — Rebuilding the east end of Dauphin Island to repair years of erosion would cost up to $12.8 million, according to a preliminary study released on Thursday.

Dauphin Island leaders gathered near Fort Gaines, the historic Civil War site on the barrier island, to announce the proposed project that would renourish about 10,200 feet of east-end beach using an estimated 1.14 million cubic yards of sand, according to the report by engineering firm WRScompass in Tampa, Fla.

Officials have been concerned about erosion on the east end, the more stable part of the island with a natural dune system and a forest of pine trees. Evidence of erosion there lies about 300 feet from the Gulf shore, where parallel lines of rocks — manmade sand traps known as groins — protrude from the water. The groins were built nearly a century ago, constructed perpendicular to a shore that no longer exists.

Town officials have argued that Fort Gaines, the local Audubon Bird Sanctuary supporting migratory birds, the local seafood industry and tourism dollars generated by the island are at risk if erosion continues to destroy the shoreline. Leaders hired a lobbyist in Washington, D.C., to secure funds for a beach renourishment project.

"The impact of Dauphin Island as a barrier island ... is more far-reaching," said Dauphin Island Mayor Jeff Collier. "It's not just our problem."

WRScompass conducted the preliminary beach rebuilding project study free of charge to the town, but officials said it would cost up to $1.5 million to complete a comprehensive study with more details about how to more forward with the project.

The rebuilt beach area would extend from Fort Gaines to the Dauphin Island Elementary School, town officials said. The project could add between 200 feet and 400 feet of beach extending toward the Gulf, according to the report.

The project would cost between $11.5 million and $12.8 million, according to the report, although Collier said the price could change depending on where the added sand is dredged from — and how far the site is located from the island.

Scientists have blamed erosion of the Mississippi-Alabama chain of barrier islands on dredging of ship channels, sea level rise, and stronger, more intense storms.

"There aren't many communities... that have to worry about their town physically going away," Collier said.

Brent Anderson, WRScompass vice president and technical services director, said he couldn't say exactly how long an engineered beach would last, but it would be constructed "as permanent as it can be made" with additional maintenance work after strong storms.

Officials said several other coastal cities have rebuilt their beaches, such as Gulf Shores and Miami Beach.

Scientists have said that the east end is the more stable part of the island when compared with the west end, a long spit of sand where beach houses on stilts line Bienville Boulevard.

It's on the west end that another engineered project was built on the beach. A three-mile protective berm built with about $3.6 million in sand was washed away by Hurricane Gustav, which struck Louisiana on Sept. 1. It was built last year to replace a $1 million berm that was destroyed by Tropical Storm Isidore in 2002.

Collier said he will be meeting with FEMA officials today to discuss hurricane damage repairs, including the berm.

Mike Moore, FEMA's disaster coordinator for Alabama, said the agency is in the process of approving some funds for storm repairs to the island, including about $3.6 million to remove and recover sand from the public right of way. Gustav covered the west end's roads with several feet of sand.

Moore said the island could seek federal funds for a replacement sand berm, but there's been no decision on its design or cost.

(The Associated Press contributed to this report.)

Posted by Kelby Linn on October 24th, 2008 8:42 AMPost a Comment (0)

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Losing Key Barrier Islands like Dauphin Island is a major problem.

October 24th, 2008 9:23 AM

ALABAMA VOICES: Losing key barriers

By Scott L. Douglass

Sandy beaches and barrier islands are important economic, environmental and quality-of-life assets in south Alabama. But nationwide, Dauphin Island has become the poster child for unwise coastal development and the folly of living on a barrier island.

Indeed, it has been cast in the national media as an example of the long-term fate of all developed barrier islands.

The island has been cut in two pieces and the western portion of "east Dauphin Island" overwashes repeatedly as hurricanes pass even hundreds of miles to the south. Many of the homes there have been destroyed, and all have been damaged multiple times by storm surge overwash and waves in the past decade.

The collapse of the west end of the island exposes the soft underbelly of the marshes of south Mobile County and Bayou La Batre to bigger waves, more erosion and higher storm surges. This will cause problems with the built infrastructure as well as oyster beds and fishing.

The beaches of the easternmost mile of the island have eroded over 700 feet to the north in the past few decades. Many of the changes to Dauphin Island are natural fluctuations. The migration of Sand Island onto Dauphin Island by the fishing pier has happened before -- roughly 300 and 150 years ago -- and it is right on schedule again.

This is one natural way that the island heals itself. Much of the island's damage has occurred in storms. But blaming storms for beach erosion is a bit like blaming gravity for plane crashes. Yes, gravity pulled the plane out of the sky, but there was obviously something wrong with the plane just before it fell.

There are only three proven ways to save the island's beaches, and some combination of these must be pursued.

One way is to back off, to retreat. Moving construction back away from the eroding shoreline and away from hazardous overwash areas provides a sandy buffer between the surf and the buildings and lets the natural processes occur without damaging things.

Most of the eastern end of the island, including the old town center, is protected by some of the largest dunes on the Gulf of Mexico. But elsewhere on the island, unless we are willing to permanently remove our houses, condos and businesses, some combination of the other two proven approaches -- beach nourishment and sand bypassing -- are required.

The island is downdrift of the Mobile Ship Channel, one of the largest sand thieves in America. More than 20 million cubic yards of sand have been permanently removed from the island's beach sand system needlessly by the ship channel.

Sand dredged from the outer bar of the ship channel must be "bypassed," i.e. placed on the beaches or in shallow water so that it can migrate quickly to the island's beaches.

The deficit of sand imposed by this tremendous withdrawal of sand over the past few decades should be replaced. Dauphin Island should really just be the poster child for the folly of living downdrift of a federal navigation channel.

Beach nourishment has restored the beaches of Baldwin County and more than 350 miles of other beaches throughout the country, and it can restore the beaches of Dauphin Island.

A well-engineered beach restoration plan is not like the disastrous, so-called FEMA berms that have been constructed twice on the island in the past decade. There is no way those could have worked. They violated some of the principles of successful coastal engineering. Essentially, they were attempts to stack sand on the beach unnaturally, and as such were doomed to fail.

Beaches take a certain shape in response to waves and tides and good coastal engineering tries to replicate those natural shapes. With limited resources, we must spend all available money on well-engineered projects that will succeed.

American beach communities with erosion problems that survive and thrive have one common characteristic -- everyone is on board with the need for sand bypassing and beach nourishment.

For Dauphin Island, this means the residents, the elected town government, the Park and Beach Board, the business community and the property owners' association as well as the Alabama State Port Authority and all the county, state and federal elected officials who represent the area.

Successful beach restoration projects in America are like a three-legged stool. The legs are the good engineering, the financing and the public perception. Without three strong legs, the stool collapses.

To convince citizens and elected officials to financially support island beach restoration, public access to the beaches of the island could be provided at every street end.

The new, open beach provided by the town is a step in the right direction. Unless public access to the island's beaches is improved, it is likely that the best solutions will not be politically possible and the island beaches will continue to deteriorate for another generation.

Scott L. Douglass is the author of the book "Saving America's Beaches: The Causes of and Solutions to Beach Erosion" and is a professor of civil engineering at the University of South Alabama.

Posted by Kelby Linn on October 24th, 2008 9:23 AMPost a Comment (0)

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