City Analyzing Samples from Mouth Bar In Hopes of Determining Volume Due to Harvey

According to Stephen Costello, Chief Resiliency Officer for The City of Houston, the City contracted with a company called Tetra Tech to take core samples earlier this week from and around the mouth bar on the West Fork of the San Jacinto.

Why Core Samples?

The mouth bar is a giant sand bar at the mouth of the river where it meets the lake. The size of it has concerned residents throughout the Lake Houston Area since Harvey. It has the potential to back water up on both sides of the river and worsen flooding.

Some background. The Army Corps initially excluded the mouth bar from its current dredging program on the west fork. Their reason: a small part of the bar existed before Harvey. FEMA, which is funding the dredging, by law cannot spend money on remediation for things that existed before the disaster in question.

It took months for the City, FEMA and the Army Corps to agree on a way to estimate the volume of sand deposited by Harvey. The answer says Costello: something called the Stockton protocol that he says was developed after Superstorm Sandy at Stockton University in New Jersey.

Analysis Due by End of February

The core samples will be key to estimating pre- and post-Harvey volumes. Costello says engineers will look at density and color of sand grains to help estimate where sediment from one storm stops and another starts.

Costello hopes engineers will complete their analysis by the end of February. In the meantime two other efforts are proceeding simultaneously.

Search for Suitable Disposal Site Continues

The Corps will evaluate one property for suitability as above-ground storage. Separately, others are also out looking at sub-surface storage sites (i.e., old sand pits). Several have been located. The cost and safety of above ground and below ground storage will be weighed against the possibility of hauling material off by truck. Distance between the dredge and disposal sites also affects pumping costs.

All this will take time, especially if a full-blown environmental study is necessary for the above-ground option. Costello says the Corps has told him that could take four months to two years.

Evaluating Plan B

Because of delays, Costello is starting to worry that delays may cost taxpayers the opportunity to save $18 million. That’s the cost to remobilize a second dredging project if the current dredging project cannot be extended.

Accordingly, Costello is pursuing two options. The first involves praying (that’s a joke). The second involves working back through the Texas Division of Emergency Management to get FEMA to declare the mouth bar part of the original emergency mission. The Corps seems to move much faster when orders come from FEMA, several sources tell me. Maybe we should start praying too. (That’s not a joke.)

Money, according to Costello, should not be a problem. FEMA has approved the use of debris cleanup money from Harvey for dredging. He believes enough money remains in that fund to cover the City’s cost share.

Where Current Dredging Project Stands

The Corps estimates that the current dredging project is 45% complete. They hope to complete dredging by the end of April.

City contractors are still removing downed trees from Lake Houston as a result of Hurricane Harvey’s destruction.
The Callan Dredge is currently working the area near Kings Harbor at the West Lake Houston Parkway Bridge.
The immensity of the equipment underscores the need to keep crews working at the end of the current project on the mouth bar. Remobilizing all this equipment could cost $18 million or more if delays create a need to remobilize.

Posted by Bob Rehak on February 7, 2018

527 Days since Hurricane Harvey