Save Date: Public Input Scheduled for Adlong Ditch Project on May 25

The Harris County Flood Control District (HCFCD) will hold a virtual Community Engagement Meeting for Adlong Ditch Conveyance Improvements on May 25. The purpose: to share project information and update residents on status of the project.

This project is in the Preliminary Engineering Report (PER) stage. PER objectives include delivering more detailed recommendations for flood damage reduction and an implementation strategy.

The Virtual Community Engagement Meeting will be held on:
WEDNESDAY, MAY 25, 2022
6:30 – 7:30 p.m.
Join online at: PublicInput.com/Adlong
Or by phone* at 855-925-2801 with Meeting Code: 4964

2018 Bond Program funds will pay for this project. Community engagement is an important component of the Bond. And HCFCD invites your participation.

About the Meeting

The meeting will begin with a brief presentation to share project updates. A moderated Q&A session with Flood Control will follow. Residents may submit questions and comments before, during and after the meeting and throughout the public comment period. Any comments not addressed during the Q&A session will receive a response at the conclusion of the public comment period.

Even if you can’t attend the virtual meeting, you can register to receive future project updates. HCFCD will post a recording of the meeting on the District’s website and YouTube after the event.

If you need accommodations because of a disability, please contact 346-286-4040 at least 48 hours prior to the meeting. For questions, please contact the Flood Control District at 346-286-4000, or fill out the comment form online at hcfcd.org/f-43.

*If you attend by phone only, maps and other exhibits will not be visible. However, you can find those after the meeting at hcfcd.org/f-43.

Location of Ditch

Adlong Ditch runs north to south through a mostly rural area, east of Lake Houston between FM2100 and Cedar Bayou. The ditch runs from approximately Old Atascocita Road on the north to its confluence with Cedar Bayou east of Crosby.

*Adlong Ditch starts near the center of the frame and runs toward the lower right. See Q128-00-00 where it crosses Highway 90.*

Arkema Disaster Happened Near Adlong Ditch

A high-level executive of the flood control district described flooding in this area during Harvey. He said it was “a giant lake.”

The U.S. Chemical Hazards and Safety Investigation Board (CSB) said the flooding directly contributed to the disaster at the Arkema chemical plant, one block east of the ditch on Highway 90.

*Adlong Ditch (left) flooded Arkema Chemical Plant (right) during Harvey, cutting off an evacuation route because of toxic fumes released.*

According to the Board, Harvey disabled refrigeration systems at the Arkema plant in Crosby, where the company manufactures organic peroxides normally stored at -20 degrees F. As temperatures increased, the peroxides spontaneously combusted on August 31.

Arkema had a history of flooding, but never as bad as it did during Harvey. As a result, managers did not initially consider the plant’s safety systems at risk. But floodwaters at the plant during Harvey eventually reached 5 feet high – incredible for such a flat area.

*Arkema Facility during Harvey. Rescuing part of the crew riding out the storm* *inside the plant*.

The full report by the CSB details a series of catastrophic, bone-chilling miscalculations. It serves as a grim reminder of the power of floods and the need for preparation.

Residents within a 1.5 mile radius had to be evacuated. And because plant managers knew from experience that miles of surrounding roads would become impassable, they left a crew inside the plant to ride out the storm.

Not much later, 350,000 pounds of organic peroxide spontaneously combusted. Residents living within 1.5 miles of the plant had to evacuate and could not return home for a week. The incident endangered the lives of employees, first responders and neighbors. Highway 90, an evacuation route, had to be closed for days because of toxic fumes.

Cedar Bayou Flood Risk Reduction Study

Ironically, Harris County Flood Control District (HCFCD) had started a Cedar Bayou Flood Risk Reduction Study six months before Harvey as part of its Cedar Bayou Plan. This study investigated existing flood hazards and identified potential future drainage improvements to help mitigate flooding and flood damage.

Included in the study were the Cedar Bayou main stem (Q100-00-00) and 18 of its tributaries deemed as priorities, including Q128-00-00 (Adlong Ditch).

Outline of Long-Term Solution for Adlong Ditch

The long-term proposed solution for Adlong Ditch includes:

A large regional stormwater detention basin (approximately 120 acres in size which would provide approximately 511 million gallons of storage volume
Widening and deepening the channel
Structure improvements to increase the capacity of existing bridges/culverts.

Short-Term Objectives

The short-term recommendations include:

Acquisition of right-of-way (ROW) for future improvements
Initial construction of the regional stormwater detention basin.

Project Benefits

Implementation of the long-term proposed solution would be phased as funding becomes available. The project benefits include:

More effective channel conveyance to contain future 100-year flows.
Removal of inundation of up to 17 structures downstream of US 90 in the 100-year event.
Removal of inundation of approximately 1,169 acres and 4.5 miles of road in the 100-year event,
An estimated reduction of $1.1 million in damage

Posted by Bob Rehak on 5/13/2022

1718 Days since Hurricane Harvey