Men's Breakfast Report, October 2013

 

The Men’s Breakfast Group met Saturday, October 12th with George Kidwell, chairman of the Velasco Drainage District. George was an engineer with Dow Chemical Company and active in Lake Jackson civic affairs when he was asked to become a member of the Board of the Drainage District. He went and got advice from a long time expert in drainage. The first thing he was told was that water always flows downhill. The second thing was that this area is flat so water does not flow out. The third thing is that if you want to remove water from the area you have to pump it. George decided that he could handle the position and has been on the board for 29 years. This is an elected position so he has run for election several times.

The Velasco Drainage district covers the southern end of Brazoria County between the Brazos River and Oyster Creek up to Bastrop Bayou. The district maintains sixty miles of levees, fourteen pump stations and the Brazos River tidal gate.

The levees were considered to be in excellent shape until Hurricane Katrina. The causes of the levee failures in New Orleans were analyzed and the lessons are being applied to all other levees in the country. Some of these failure mechanisms are present in parts of our levees. George discussed various mechanisms and how they applied to our levees.

In New Orleans, one levee was built on peat moss. When the water pressure built up, the levee was shoved 600 feet over the peat moss, opening a big gap. Other levees were built on porous sand, both in front and back of the levee. When the water rose it seeped under the levee and the levee eventually sank in the quicksand. Some levees had penetrations such as pipelines which acted as weak points that allowed leaks to start. Some barriers were flood walls instead of levees. Where the flood walls were not anchored deeply enough or with a broad enough base they were simply pushed over. Some levees had too great a slope in front or back so they slumped away when the water rose.

A major problem with our levees is penetration. The district has already removed the salt cedar that was growing on the levees. The salt cedar roots create weak spots that can become leaks in the levee, especially when the tree dies and the root decays. There are a large number of pipelines passing through or under the levees. The district is working with local industry to fix this problem. Some of the pipes are obsolete and can simply be removed. Others can be rerouted so they do not provide a hazard. Other mechanisms will be required on some pipelines.

We do have some flood walls. They will have to be checked to see if they go deep enough or have enough backing. Walls that do not meet new criteria will have to be strengthened or modified.

A few levees have too great a slope and will need more backing or moving. One problem are levees near the harbor. When the harbor was deepened the slope was inadvertently increased beyond proper limits. It has not yet been decided what will be done about it or who will pay for it.

One of the most problematic levees is the Dow barge canal. The canal looks like a spear thrust right up the middle of Brazosport. The canal was built in the 1940s to serve Plant B and as a source of seawater for the Plant B magnesium plant. The levees on either side of the canal are simply the spoil from dredging the canal, and not purposely- built levees. This means that the foundations and material are not correct in many places. It was suggested that another tidal gate be constructed for the barge canal but this is considered to be more expensive than armoring the levee.

After Katrina, the Federal Emergency Management Agency (FEMA) decided that areas within levees would not be considered to be protected unless the levees were recertified by the Army Corps of Engineers. The Corps does not have the money to do this so the district has to hire outside engineers to analyze the levees. This first required the Corps to come up with criteria for the levees and then for the district to get the study made and approved. FEMA was threatening to declare that the levees were inadequate and that all of Brazosport would be in the flood plain. This would make flood insurance prohibitively expensive and prevent almost all development, residential, commercial and industrial. George had to hire a lobbyist to talk sense to the bureaucracies in Washington. The red tape has finally been resolved. We are allowed to consider the present levees as sufficient protection from flooding for five years. At the end of this time the levees must have been brought up to modern specifications. The upgrade will cost eighty million dollars and is why the bond issue is on the November ballot.

George was asked about the rise in sea level caused by climate change. A small rise, one foot or less, would not be a major problem. George does not believe that climate change is a real problem and therefore is not something he is going to take into account. A similar problem is subsidence. The Brazosport Water Authority is planning to construct a desalinization plant that will use brackish water from an aquifer under Brazosport and vicinity as feedstock. If done improperly, this pumping could cause subsidence and effectively lower the levees. George did not have any comments on this potential problem.

The men had an interesting discussion and a good breakfast. Our next meeting will be on November 9th.