Why the City Needs Regular River Surveys and Maintenance Dredging

Three months after supposedly reaching an agreement in principle to remove the mouth bar, FEMA, the Army Corps, the State and City still have no agreement in writing. From Day 1 of negotiations, FEMA and the Corps have consistently said they can’t address pre-Harvey conditions. I’m beginning to believe them. How did we reach this impasse and how can we move forward?

FEMA’s Dilemma

The Stafford Act (FEMA’s enabling legislation) prohibits FEMA from funding repairs not directly related to Harvey. But, because the City conducted no surveys after the Memorial or Tax Day Floods, it cannot prove how much came from Harvey. Yet it has asked FEMA and the Corps to remove the entire mouth bar.

The City’s Dilemma

The City of Houston has done little to maintain Lake Houston, especially the West Fork of the San Jacinto near Kingwood. Lack of regular surveys and maintenance dredging make city officials look like they’re trying to get others to clean up their mess.

Historical Perspective

Decades ago, after the 1994 flood, the City hired Brown & Root to study sedimentation in the lake, which includes about 13 miles of the East and West Forks of the San Jacinto. Engineers recommended surveying the river after every major storm and dredging when necessary to reduce the risk of flooding. They even pinpointed where sediment would likely build up and pointed out that the West Fork was capturing 42% of all the sediment coming into the lake (see page 9). However, before Harvey, the City never dredged and rarely conducted surveys – decisions that haunt us today.

The mouth bar. Sand, in part from the mines, has almost totally blocked the West Fork where it meets Lake Houston. Unofficial before/after measurements show that as much as ten feet was deposited in this area during Harvey (five below water/five above).

Sedimentation: Danger that Can No Longer Be Ignored

One insidious aspect of sedimentation is its invisibility. Like gunk in pipes, you can’t see it – until water backs up and floods your home. That’s exactly what happened to thousands of homes during Harvey. The problem which had slowly built up for years, went from sub-acute to critical almost overnight because of the massive volume of sediment deposited during Harvey.

That brings us to our present impasse.

No News is Bad News

The City, FEMA, the Army Corps and the State have argued about this for at least six months. We thought they reached agreement in principle to remove the mouth bar three months ago. But still no official announcements have been made. Sadly, it didn’t have to come to this:

  • If only the City had followed the advice of the experts it hired…
  • If only the City had maintained its property…
  • If only the City could document how much Harvey contributed to the blockage…
  • If only the City had acted years ago to limit sand mining in the floodway of the river…
  • …we could have been working on the mouth bar already. Instead…

Problem Becoming Demonstrably Worse

In the 80 years since we started keeping records on the West Fork at US59, the river has crested over 50 feet 40 times – once every other year. But in the last 11 months, floods have reached that height SIX times – more than once every other month. We topped 50 feet in the latest flood just minutes ago. All resulted from relatively minor rains. This sudden surge in frequency did not result from global warming.

Is it all a statistical fluke? Wetter than usual weather? El Niño? Upstream development? Perhaps some of each. But one would have to be blind to dismiss the sediment buildup in the river. A delta is marching steadily downstream, creating blockages that back water up.

The West Fork just before Kingwood’s annexation in 1996 and after Harvey. Comparison shows advancing sediment buildups blocking the river.

The High Cost of Ignoring Expert Advice and Routine Maintenance

Harvey brought the high cost of ignoring expert advice and routine maintenance into sharp focus. The lack of a survey that could have been conducted in a few days is costing the City months of delays and potentially tens of millions of dollars in State and Federal assistance. This exposes hundreds of thousands of residents to needless flood risk and undermines property values.

What Needs to Happen

All of this underscores the need to budget for and maintain one’s own property. Drainage fees, which we just put a lock box around, should easily handle the City’s portion of dredging projects and surveys.

How do we break this impasse?

FEMA and the Corps need to restore the conveyance of the river that existed before Harvey. Estimate it using available evidence like aerial photos and satellite images. We’ll never have an exact figure. So quit using that as an excuse to put hundreds of thousands of people at risk. Let’s get started with dredging what we can. Legally.

In return, the City could commit to annual river surveys that document the status of the river before each hurricane season.

The City also could commit to a regular maintenance dredging program to keep sediment at a sub-acute level. The annual surveys will determine the exact amounts and frequencies.

The City could also throw its weight behind legislative efforts to move sand mines out of the floodway, where they contribute to levels of sedimentation far beyond natural rates.

I’m not a mediator and I’m not the Mayor, but that sounds like a fair compromise that can protect residents as well as officials on both sides of this negotiation.

Floods don’t happen as often as police or fire emergencies, but when they do, they affect hundreds of thousands of people in ways that can be just as life altering. This is a public safety issue. Let’s go. Reach an agreement, please!

These are my opinions on matters of public policy, protected by the First Amendment of the U.S. Constitution and the Anti-SLAPP statute of the Great State of Texas.

Posted by Bob Rehak on January 4, 2019

493 Days since Hurricane Harvey