Hurricane Harvey deposited a giant sand bar at the mouth of the San Jacinto West Fork that formed a dam behind the dam. More than 3000 feet long and 3000 feet wide, it backed water up into thousands of homes and businesses. Ever since then, removing it has become a major focus of flood mitigation efforts in the Lake Houston Area.
As of this morning, virtually all of the above water portion was gone. So were there two excavators working on it last month. The portions that remain are so narrow that they are starting to crumble into the lake. The remainder of the job will likely have to be performed from pontoons. See the pictures below, all taken on 11/5/2020.
What you see in the photo above is the last of an estimated 400,000 cubic yards that the City of Houston is removing.
With the above water portion of the bar removed, it will be more difficult to visualize the problem from now on. But sand bars are like ice bergs. The majority of them lurks beneath the surface. And an underwater plateau still remains. It stretches from the foreground in the photo above almost all the way to the bridge in the background.
The graph below shows what it looks like. The blue line represents the water level. The gold line represents the deepest part of the channel from where the Corps finished hydraulic dredging in September 2019 down to the FM1960 bridge.
Stephen Costello, the City’s flood czar, is working to formulate plans for the next phase of dredging and hopes to announce them this month. FEMA has said that it will pay for dredging an additional million cubic yards from the mouth bar area.
Current Spoils Going to Good Use – Expanding FM1960
Currently, the spoils are being moved upstream to Berry Madden’s property on the south side of the river, opposite River Grove Park in Kingwood. Madden has plenty of room for more. See below. He says that TxDoT will use spoils currently stored on his property to widen FM1960. That project should start in the next few days. He also says that TxDoT estimates they will use spoils at the rate that dredgers are currently bringing them to his property.
That should create even more room for storage on Madden’s property.
Next Dredging Targets
In addition to dredging a channel through the mouth bar, the City still needs to open up the mouths of several streams and drainage channels around Lake Houston. Rogers Gully, for instance, has formed it’s own mouth bar. See below.
The City also needs somehow to address the dramatic growth of an East Fork San Jacinto Mouth Bar that grew 4,000 feet during Imelda.
Kudos to Mayor Pro Tem Dave Martin, State Representative Dan Huberty, State Senator Brandon Creighton, and U.S. Congressman Dan Crenshaw who have worked tirelessly to address these issues since Harvey.
Posted by Bob Rehak on 11/5/2020
1164 Days since Hurricane Harvey