Compared to July, Woodridge Village excavation activity almost doubled in August.
As of close of business on September 6, 2023, Harris County Flood Control District (HCFCD) contractor Sprint Sand and Clay has excavated 146,104 cubic yards of material to expand the stormwater detention basin capacity on Woodridge Village.
At the end of July, Sprint had excavated 135, 751 cubic yards. That means the company excavated another 10, 353 cubic yards in August, or 6.4 acre feet.
And that brought the total excavated to date up to 361.6 acre feet, or 94% of the Atlas 14 requirement.
Stepping Up Stormwater Detention Capacity
When Perry Homes sold the site to HCFCD and City of Houston, the site had five detention basins totaling 271 acre feet. The new basin has the potential to more than double that volume.
Think of the expansion of Woodridge Village stormwater-detention-basin capacity in four stages:
- The starting point, i.e., what the site had when purchased from Perry Homes.
- An additional amount that Sprint has excavated to date.
- The Atlas-14 requirement.
- The contract max (500,000 cubic yards).
Here’s how the various stages look in a table.
|Acre Feet of Stormwater Detention||% of Atlas-14 Requirement||% of Ultimate|
|Site Had When Purchased from Perry Homes||271||70%||47%|
|Has as of 9/6/23||361.6||94%||62.3%|
|Atlas 14 Requires||385||100%||66%|
|If Sprint Excavates All 500K Cubic Feet||580||150%||100%|
I based all calculations on original construction plans, HCFCD monthly reports, Atlas-14 Requirements and Sprint’s contract.
Photos Taken 9/7/2023
Here’s how Woodridge Village excavation activity looks on the ground.
Outline of Excavation
Harris County Commissioners Court approved the contract with Sprint Sand and Clay on July 20, 2021. It obligates Sprint to remove at least 5,000 cubic yards per month. Excavation started on January 27, 2022.
Sprint will make only $1,000 from its Woodridge Village excavation contract with HCFCD, but will make its profit by selling the dirt at market rates. An engineer familiar with HCFCD operations estimates that if HCFCD had to pay market rates to have that 146,000 cubic yards moved, it would have cost taxpayers between $1.46 million and $2.9 million. He based those numbers on recent bids.
So, the Sprint contract is a good deal for taxpayers, but it carries some uncertainty with it.
If the demand for dirt dries up, excavation could slow or stop.
But simply excavating the dirt isn’t the end of the job. Harris County still needs to slope the sides, plant grass, and tie the new basin into the site’s existing stormwater-detention-basin network.
HCFCD awarded the engineering project for all that to Halff, based on the company’s qualifications. HCFCD is currently negotiating the scope of the project with Halff.
At the current rate of excavation, Sprint could reach Atlas 14 requirements by the end of the year. But the contractor is still less than a third of the way through its contract maximum of 500,000 cubic yards.
Construction of Taylor Gully conveyance improvements cannot move forward until the appropriate stormwater mitigation on Woodridge Village is in place first. Only one thing is certain at this point. That could still be awhile.
But there is good news. In the meantime, the extra Woodridge Village detention basin capacity will go a long way toward reducing flood risk for people downstream.
Posted by Bob Rehak on 9/7/23
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