Southern California should heed lessons of Katrina

Lou and I were horrified when we saw the eye of Hurricane Katrina

make landfall just east of Pass Christian, Miss., last Monday. We had

a very personal interest in this killer storm.

Last spring, my sister, Ann, and her husband, John Bray, moved

from Oceanside to the little coastal community of Diamondhead, Miss.,

a few miles east of Pass Christian.

By lucky coincidence, they happened to be back in California last

week when Katrina struck. They had boarded up the windows of their

new house prior to the hurricane. But without either landline or

cellular telephone service in coastal Mississippi after the storm,

they didn’t know if their house was standing or flattened.

For obvious reasons, the human tragedy in New Orleans became the

focus of media attention, and the tremendous wreckage at the eye of

the storm received relatively little airtime.

As strange as it may sound, the ongoing loss of coastal wetlands

may be one of the reasons for the extent of the devastation in New

Orleans. Over many thousands of years, the Mississippi River has

deposited silt at its mouth, building up an enormous delta. The delta

is famous for its blues music and its crayfish cuisine, but it also

has been of hydrological importance to the city of New Orleans.

That delta separated New Orleans from the waters of the Gulf of

Mexico. Mangrove swamps and sea grass marshes provided a barrier to

storm surges. But that barrier has eroded at an alarming rate, and

its ability to shield the city from storms has eroded with it.

A recent study by the University of Texas found that Louisiana is

losing its delta marshes at the astounding rate of 60 acres per day.

This loss is due to three main factors: rising sea levels, ground

subsidence and redirection of sediment.

Sea level is rising in Louisiana and around the world. Some say it

is due to global warming caused by excessive burning of fossil fuels.

Others believe global warming may be due to other causes.

Regardless of the cause, the rise is real and people would be

foolish to ignore it. Coastal areas need to be especially careful in

their planning, a lesson that Huntington Beach needs to learn from

Katrina.

Ground subsidence in the delta is tied to Louisiana’s status as

one of the leading petroleum states in the nation. When oil is

withdrawn from the ground, the ground loses internal pressure and the

surface sinks. According to the U.S. Geological Survey, the

Mississippi Delta is sinking faster than any other part of the

country, and the oil industry is a major cause.

Huntington Beach also has experienced oil-related subsidence. Some

areas of Bolsa Chica subsided by up to three feet during the heyday

of our local oil production. Long Beach had it even worse, with some

areas dropping by nearly 20 feet due to oil production.

The good news for us is that wells in this area now pump water

back into the ground to replace the lost petroleum. Since this

practice began in the 1960s, subsidence from oil extraction has been

minimized. Subsidence, however, still may be a problem in Orange

County because freshwater wells pull too much water out of the

ground.

Of all the changes people have made to the Mississippi delta, the

worst one may be channelization. Much of the delta has been cut off

from the flow of the muddy waters of the Mississippi because of the

construction of flood-control barriers. This eliminated the natural

deposition process that is so important for maintaining the delta.

The constant deposit of mud from those waters gradually built up

the delta from the saltwater around it. Accumulation of silt may

sound minor, but remember, it was the silt of the Nile that allowed

Egypt to become one of the first great civilizations.

In Louisiana, the accumulation of silt used to balance out the

erosive force of storms coming in off the Gulf of Mexico. As we saw

last week, those storms still come in.

What is different is that silt accumulation is now prevented by

the channelization of the river. All the silt is deposited at one

small point at the tip of the river. The rest of the delta is

silt-starved.

The result is that the gulf is overtaking the delta. Last week, it

even overtook New Orleans.

Channelization is a mistake that we have made in a large way here

in Southern California. And it hurts us in ways similar to the loss

of wetlands along the Gulf Coast.

What we have lost here is sand. The sand that used to pour out of

our river mouths, especially during major storms, is now blocked by

dams and other water-control structures.

This has made it necessary for us to restore sand to our beaches

at great cost. “Sand replenishment” is now a multimillion-dollar

annual expense for beach communities in Southern California.

My sister Ann was able to reach a neighbor who had returned

briefly to Diamondhead to assess the damage. Although their

neighborhood was several miles inland, the storm surge flooded the

area to a depth of 12 feet during the height of the storm. Ann and

John’s brick house is one of the few homes that are still standing.

* VIC LEIPZIG and LOU MURRAY are Huntington Beach residents and

environmentalists. They can be reached at [email protected].

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