Addressing Man-Made Aspects of the Harvey Disaster in Northeast Houston

By Bob Rehak

Note: This article first appeared in the Houston Chronicle Gray Matters section
on January 29, 2018 under a different headline.

See https://www.houstonchronicle.com/local/gray-matters/article/Harvey-showed-why-we-have-to-stop-mining-sand-in-12533339.php?cmpid=gsa-chron-result

Bob Rehak, a retired businessman living in Kingwood, has become active in flood recovery efforts.

(Houston, March 4, 2018) Hurricane Harvey flooded more than 16,000 homes and 3,300 businesses in the Lake Houston area according to SBA estimates released in November, 2017. According to Dave Martin, the area’s Houston City Council Member, damages will run into the billions and the area’s tax base could be reduced by 20 to 30 percent in 2018.

In my subdivision alone, 45 percent of the homes flooded; only two or three had ever flooded before, even in 1994 and during Tropical Storm Allison. What was different this time? Was it simply the volume of rain or was something else also at work here?

After the flood subsided, I observed new sand dunes along the shores of the San Jacinto – some higher than 15 feet! Where did all the new sand come from? Was there a connection between it and the flooding?

To find answers, I rented a helicopter and surveyed the east and west forks of the San Jacinto. My search also led to State Senate and House hearings.  I had meetings with public officials at the local, county, state and federal levels. I also interviewed flood experts from Galveston and Harris Counties. Here is what I found.

Humans exacerbated flooding along the San Jacinto
in ways that they didn’t in other parts of Houston.

Mitigating the risk of future flooding will almost surely, in my opinion, require eliminating sand mining operations on both the east and west forks of the San Jacinto and other tributaries that form Lake Houston. Adjacent to Kingwood alone, these mines have denuded 3000 acres of riverfront – 20 percent of the size of Kingwood. But they are far from the only sand mining operations.

While virtually invisible from the ground, from the air their devastation is shocking. Satellite and aerial photos reveal that Harvey’s floodwaters breached the dikes surrounding the mines. The swirling floodwaters scooped up an incalculable amount of sand and deposited it downstream, blocking and backing up drainage ditches, streams, and the river itself. Many of my photos show sand in treetops. If the sand reaches that high onshore, imagine how much it reduced the carrying capacity of the river!

Certainly, the extreme nature of Harvey made large-scale damage inevitable. But were it not for the actions of humans, many homes and businesses that never flooded before might have been saved.

Man-Made Problems

Collectively, we:

1. Allowed mining operations to clog the San Jacinto river with sand.
2. Failed to follow engineer’s recommendations to dredge the river.
3. Designated multiple agencies with conflicting mandates to govern the river.
4. Created a San Jacinto River Authority that failed to protect downstream interests.
5. Created a bottleneck in the river with dams that have different release rates.

We need to move from identifying culpability to fixing problems. By acting now to de-bottleneck the river and the politics that surround it, we can improve public safety and mitigate damage from future storms.

Recommendations

Here, in my opinion, is what we should do to address each of these issues. Many experts agree.

1. Reduce the rate of sedimentation: Buy land occupied by sand mines and turn it into parks. Stabilize soil with plants, trees and grass to reduce erosion.
2. Dredge the San Jacinto: We must improve the velocity and carrying capacity of the river. A Brown & Root study released in 2000 recommended dredging to mitigate flooding. Yet so far, not one yard of sand has been removed. Sand deposited during each new flood reduces river capacity. The last sedimentation survey of the west fork in 2011, showed an average depth of less than five feet. It’s now inches deep in many places. Parts have become unnavigable with boats that draw as little as 18 inches.
3. De-bottleneck the Politics of Flood Management: We need to create a UNIFIED command structure along the ENTIRE river with the PRIMARY mission of reducing flooding. Currently Harris County Flood Control and the San Jacinto River Authority (SJRA) govern the river. However, the SJRA’s enabling legislation gave it responsibility for flood control and environmental preservation on one hand, and water conservation and economic development on the other. These mandates can conflict with each other. In the agency’s 81-year existence, it has allowed sand mines to decimate the banks of the river and failed to build even one flood-control dam. The SJRA has certainly helped economic development in Montgomery County. However, Montgomery County sand mines along the river have contributed to flooding in Harris County. We need to establish flood management as the top priority for all agencies governing the San Jacinto.
4. Maintain an SJRA board that represents the upper Lake Houston area:  We should urge the governor to make sure Lake Houston area residents are always represented on the SJRA board. People living here suffered most of the consequences of SJRA actions during Harvey, but were not represented on the board at the time;
5. Modify the Lake Houston Dam: Pre-releasing water in anticipation of a major storm can reduce flood damage because lowering a lake’s level reduces the height of the flood. However, Lake Houston cannot shed water as quickly as Lake Conroe because Lake Houston has a fixed-height spillway and Lake Conroe has tainter gates. The SJRA cited this as their reason for not pre-releasing water from Lake Conroe; they said they feared flooding the Lake Houston area. We need to add tainter gates to Lake Houston’s dam. That will let both lakes pre-release water at the same rate, eliminating the Lake Houston bottleneck and reducing future flood damage.

Generic solutions designed for other parts of Houston may help in the upper Lake Houston area, but they won’t address the root causes of flooding here. These recommendations will. We need action now. The next hurricane season is just three months away! The following photos illustrate why we need to act quickly.

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Originally published in the Houston Chronicle on 1/29/2018 in their Gray Matters column. This version contains minor updates.