Yesterday, the area where a developer proposes a new high-rise development flooded for the fifth time this year. This underscores the need for remediation before any permitting.
It wasn’t an especially heavy rain last week. Kingwood received about 2.5 inches. Areas upstream averaged 3 to 4 inches. Yet the West Fork came out of its banks and flooded River Grove Park for the fifth time this year (February 26, March 28/29, July 4, December 7/8, December 27). The USGS Gage at US59 showed that the flood crested at about midnight. The crest reached almost 50 feet at US59.
Jim Zura of Zura Productions took his drone to River Grove during the last light before the overnight crest. The video shows that although the road was still useable, many of the park’s popular amenities were not. The playground, soccer fields, boat ramp and boardwalk all flooded.
Earlier this year, the US Army Corps of Engineers found that excessive sedimentation in the river contributed to excessive flooding. The frequency of these floods supports that conclusion. The Corps began dredging in late September to remove sediment, but has completed only about 20% of the project so far. Downstream blockages remain. And the biggest – at the mouth of the West Fork – is not even within the scope of the current dredging project.
The end of Zura’s video shows the soccer fields and adjoining property, including a small lake in the floodway. This flood gives us a glimpse of how a minor rain would affect the proposed high-rise development there.
The frequency of these floods underscores the need to consider the implications of permitting such a major development – especially when officials know the engineering is based on obsolete data and flood maps that in no way reflect current realities.
Until remediation efforts are complete, officials should postpone consideration of the permit. Remediation efforts include:
- Dredging the West Fork all the way from US59 to Lake Houston
- Creating additional upstream detention
- Adding flood gates to Lake Houston
- Restoring the conveyance of local drainage ditches and streams.
Rainfalls of the magnitude that caused these five floods should happen about once every 2 years according to Harris County Flood Control. This year they happened five times: 10X greater than expected. A review of peak crest data since 1929 roughly confirms these expectations. In the 80 year since then, the river crested over 50 feet only 40 times.
A review of the same data shows that the river has crested over 57 feet 9 times in the last 80 years and six times since 1994.
I believe excessive sedimentation played a role in this frequency increase. Instead of flooding every other year like this, we’re flooding almost every other month. That’s significant enough to put the brakes on development in the floodway, at least until we understand the extent of the problems and can fix them.
These are my opinions on matters of public policy. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statutes of the Great State of Texas.
Posted by Bob Rehak on December 31, 2018
489 Days since Hurricane Harvey