In July, the City announced it was wrapping up West Fork dredging and starting on East Fork dredging. It took three months for the dredgers to dredge their way through the Royal Shores channel before they could even start on the East Fork. Since then, it’s been a slow-go as round trip travel times to the placement area get longer.
Since then, the dredgers have managed to remove about 300 feet of the tip of one sandbar blocking the mouth of Luce Bayou and Red Gully (on the left in the shot above).
Note the sediment plume in the middle of the boat’s wake above. That indicates the shallowness of the river.
According to boater Josh Alberson, the depth through this reach of the river was reduced from 17 feet to about three feet between Harvey and Imelda.
Dredging: A Conveyance Issue
The dredging is far more than a recreational issue. The decreased conveyance of the river creates a sediment dam than backs water up and contributes to the flooding of homes. In fact, I passed by dozens of flooded and abandoned homes while looking for a place to launch my drone.
Mechanical Vs. Hydraulic Dredging
One can only wonder whether the City of Houston is using the right tools for the job. Even Stephen Costello, Houston’s Chief Recovery Officer, called mechanical dredging “unsustainable in the long run” when he addressed a crowd at the Kingwood Community Center on July 9.
But it may come down to a case of slow-go or no-go.
I asked a friend in the dredging business to estimate the costs of mechanical vs. hydraulic dredging. He qualified the discussion by saying that:
- To even consider hydraulic dredging you need a pit to pump the material into.
- He also suggested that to reduce long-term overhead costs, you want to be able to use the equipment year round and create a perpetual dredging program.
He said the ideal would be to go once around the lake and arrive back at the beginning when it was time to start all over again.
With hydraulic dredging, the upfront equipment and setup costs are far higher. Mechanical dredging is far slower and more expensive.
- Engineering and permitting costs
- Mobilization costs
- Depth and type of sediment
- Allowable run times
- Transport distance
- Water management
I won’t pretend that I have the answer to the question of which is better in this case: mechanical or hydraulic.
Vendor for Long-Range Dredging Plan Due to Be Selected This Month
The submission deadline for vendors bidding on a long range dredging plan for Lake Houston was 9/23. The Request for Qualifications stated that the City hoped to put contract approval on the City Council Agenda for December and start the contract in January. The selected vendor will have two years to complete the dredging plan.
It could easily take that long to finish the East Fork Mouth Bar at the current rate.
Posted by Bob Rehak on 12/3/2021
1557 Days since Hurricane Harvey and 775 since Imelda