Tag Archive for: Woodridge Village Detention Ponds

Woodridge Village Excavation Activity Almost Doubles

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 Homes27170%47%
Has as of 9/6/23361.694%62.3%
Atlas 14 Requires385100%66%
If Sprint Excavates All 500K Cubic Feet580150%100%
As of 9/6/23.

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.

The site was busier today last month. Trucks constantly shuttled in and out.
Looking NE across the new basin and the main part of Woodridge Village
Looking SW toward site entrance, Kingwood Park HS and Woodland Hills Drive
Main thrust of work during August appears to be toward the east.
An excavator loaded several trucks while I watched.

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. 

Woodridge Village Excavation and Removal
Sprint can take material wherever it wants, but must excavate from within the red boundary line.

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.

Next Steps

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

2200 Days since Hurricane Harvey

Woodridge Village Detention Basin Capacity Doubling

Harris County Flood Control District (HCFCD) contractor Sprint Sand & Clay has started laying out, clearing and excavating a large, new detention pond that will more than double capacity on Woodridge Village. Woodridge contributed to flooding hundreds of homes along Taylor Gully twice in 2019.

When the developer clearcut approximately 270 acres, the loss of forests and wetlands decreased natural detention capacity on the land. This should help restore it.

Project Outline Becoming Visible

Last week, Sprint started building a construction road into the site. This week it appears that they also dug a shallow trench outlining the perimeter of the pond and started clearing brush within it.

Photograph taken looking NE from SW corner of Woodridge Village. New detention pond will go in foreground. The shallow trench may be the outline of the new basin. Contractor appears to be staying “inside the lines.”
Earth-moving equipment worked Saturday and was back at it Monday morning, 1/31/2022.

How the Math Works Out

Sprint will ultimately excavate approximately 500,000 cubic yards of fill which translates to 310 acre feet. When Perry left the site, it had constructed 271 acre feet of detention. The site needed another 108.4 acre feet of detention pond capacity to meet Atlas-14 requirements, but will get 310 (the number of acre feet in 500,000 cubic yards). That almost triples the required additional volume and more than doubles the current capacity…all for $1000.

The $1000 is the out of pocket cost to taxpayers. Under the terms of it’s E&R contract, Sprint will make its profit by selling the dirt it excavates to third parties out of the floodplain. Their contract obligates them to excavate at least 5000 cubic yards per month. There is no monthly max.

In case you have kids or grandkids who like playing with dump trucks, 500,000 cubic yards works out to 50,000 loads. That equals the number of fingers and toes on 2,500 kids. And that’s way more than all the students in Kingwood Park High School!

Turn this into a learning exercise!

About E&R Agreements

E&R agreements provide an opportunity for making progress in advance of future basin construction. These agreements essentially provide a head start in the excavation process before the detention basin is fully designed and constructed.

Residents should beware of heavy equipment entering and leaving the site. The site will remain fenced through the completion of construction.

HCFCD expects to hold public meetings beginning in April to discuss other possible uses, i.e, recreation, restoration, etc., on the site. More news to follow.

Posted by Bob Rehak on 2/2/22, repeating digit day.

1618 Days since Hurricane Harvey

Woodridge Village Detention Ponds Passed Sunday Test, But…

On Sunday morning, Jeff Miller, an Elm Grove resident who lives near Woodridge Village, reported 5.5 inches in his rain gage. That compares to a 6.24 inch rain that fell on Woodridge on May 7, 2019, when hundreds of homes in Elm Grove and North Kingwood Forest flooded. Also, Woodridge falls about 40% short of current Atlas-14 standards required to hold back floodwater from a 100-year storm.

So you can understand how nervous Elm Grove and North Kingwood Forest residents felt, especially considering that excavation of additional detention ponds on Woodridge Village has not yet started. Regardless, Woodridge did not flood homes across the county line this time. Here’s why.

Important Factors to Consider

Other important factors came into play last weekend that should relieve some of residents’ anxiety and help explain what happened.

First, remember that on May 7, 2019, Perry Homes’ contractors had clearcut 268 acres, but had barely begun work on detention ponds. Only one of five was complete.

Second, the intensity of the May 7, 2019 rain was higher than last weekend’s. On May 7, 6.24 inches fell in 5 hours. Last weekend, 5.5 inches fell in 9 hours.

Third, in 2019, the S2 detention area had been partially excavated but didn’t have any outflow control restrictions installed yet. So it didn’t really function as a detention pond.

Fourth, contractors had destroyed a berm between Elm Grove and Woodridge, and filled in a natural stream on Woodridge. Both have since been replaced.

Fifth, by current standards, last weekend we had a 5-year storm. But the detention ponds were designed to hold what today would be classified as a 25-year storm.

Photos Taken Sunday Morning

I took the photos below Sunday morning between periodic sprinkles, several hours after heavy rain stopped. They show how the current Woodridge Village detention handled the storm. All ponds were well within their banks. One was empty.

The triangular pond on the left is N2. N1 is out of sight above it. The two ponds on the right are S1 (foreground) and S2 beyond it. N3 is out of sight at the top of the frame.
S2 was about halfway to two-thirds full.
The tail of S2 is already silting in but had plenty of room to spare.
N3 Pond on eastern edge of property was supposed to have had an outflow control device but never got one.
The Junction where water from all five ponds comes together before flowing into Taylor Gully. N3 is at top of frame.
Reverse angle shot of the Junction with Taylor Gully in the background. Note how high the detention ponds are compared to the gully. The areas that flooded so badly in 2019 are just beyond the ponds.
Water coming from the big trianglar N2 pond now has to go through these twin culverts which were almost completely inundated.
Wider shot shows volume of water backed up in N2.
Only N1 in the NW corner of Woodridge was totally dry. The outflow capacity is much greater than the inflow. So this pond provides no detention benefit whatsoever. Local resident Jeff Miller says he has NEVER seen standing water in this pond.

Big Test and Additional Excavation Yet to Come

So the Perry-installed detention passed another test. But it was far from what college students would call a final exam.

Flood Control purchased this site last year and plans to turn it into a regional detention basin by more than doubling the detention capacity. However, the excavation contract lets the contractor take the dirt when it can be sold, while only meeting minimum monthly requirements which have not yet kicked in.

Posted by Bob Rehak on 1/11/2022

1596 Days since Hurricane Harvey

The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.

Excavation of Additional Woodridge Village Detention Pond to Begin Soon

Here’s something to give thanks for on Thanksgiving. Harris County Flood Control District (HCFCD) announced Wednesday, 11/24/21, that Sprint Sand & Clay could begin excavation of another large detention pond on the Woodridge Village property as early as November 29. Lack of detention pond capacity on the property while it was being cleared contributed to flooding hundreds of homes in Elm Grove and North Kingwood Forest twice in 2019.

Homeowners evacuating during Imelda.

Not Enough Detention Pond Capacity Existed to Meet Atlas-14 Requirements

Even after Perry Homes finished building the detention ponds in its plans, the volume still fell about 40% short of the capacity needed to meet Atlas-14 requirements.

Thus, the twice-flooded homeowners have been living in constant fear since then of every storm that passes overhead. PTSD caused some to postpone home restoration or even move away. So this should come as great news to the community.

HCFCD purchased the Woodridge Village property earlier this year. Harris County Commissioners then approved a contract for excavation in July. The excavation could be sporadic, however, because of the nature of the contract.

Sprint Sand & Clay will excavate material as needed under the terms of an HCFCD E&R contract. E&R stands for Excavation & Removal. HCFCD will pay Sprint just $1000 to excavate 500,000 cubic yards. Sprint then has the right to resell the dirt to developers, contractors and road builders at market rates.

The 500,000 cubic yards should more than compensate for the 40% shortfall of detention on the Woodridge site.

Creating Extra Capacity

When Perry left the site, it had constructed 271 acre feet of detention. The site needed another 108.4 acre feet of detention pond capacity to meet Atlas-14 requirements, but will get 310 (the number of acre feet in 500,000 cubic yards). That almost triples the required additional volume and more than doubles the current capacity…all for $1000.

That extra capacity will create a margin of safety for residents in case expected rainfall rates increase again in the future.

It will also create a buffer against future development. For instance, it should help those downstream on Taylor Gully where it joins White Oak Creek. Rapid development continues upstream on White Oak Creek.

Nature of Contract Will Lower Cost, but Could Extend Completion Date

The nature of an E&R contract benefits taxpayers from a cost standpoint. It’s like getting free help. However, there’s also a potential hitch; demand fluctuation could delay the dirt’s removal. The contract obligates Sprint to remove a minimum of 5,000 cubic yards per month. But Sprint can average that, taking 10,000 cubic yards one month and none the next.

Thus, Elm Grove and North Kingwood Forest residents might see furious excavation activity one month and none the next.

Regardless, HCFCD checks progress periodically with drones. And if Sprint looks like it is not complying, HCFCD has the right to terminate the contract. Otherwise, removal of the dirt could take up to three years.

The contract gives Sprint the right to sell the dirt anywhere with one condition. The ultimate placement must be outside any known floodplain – including the 500-year/0.02% annual chance floodplain.

This is the first time HCFCD has signed such a contract for work outside of Harris County. Woodridge Village sits in Montgomery County immediately north of the county line.

HCFCD started using E&R contracts all over Harris County long before the Bond. It was a way to show progress on detention basins that HCFCD had no money to build. The Cutten Road, Lauder Road, and Aldine-Westfield basins on Greens Bayou all started with E&R contracts.

Pond Will Go in Southern Section of Woodridge

The detention pond excavation will take place close to Sherwood Trails and Elm Grove to help intercept water coming off the steep northern portion of the site. See the green area below.

The new pond will also border the road that Perry built into the site. That will help facilitate removal of the dirt. See the photo below.

Looking East. Woodridge Village as of November 11, 2021. The new detention pond will go in the big empty area between the road and ditch which leads from upper left to top middle. Sherwood Trails, Elm Grove and North Kingwood Forest are inside the trees on the right.

Construction Must Observe Stormwater Quality Requirements

HCFCD emphasized that all normal stormwater quality precautions will remain in effect. Rain that falls during excavation will be pumped into one of the site’s existing detention ponds (on the right in the photo above) to keep sediment from migrating downstream. That’s important because HCFCD just finished excavating Taylor Gully to restore its conveyance. No one wants to see it get plugged up again.

Site Closed During Construction

The construction work involves heavy machinery. Physical barriers and safety signage alerting visitors will be placed at access points. Residents should follow all posted signs and remain clear of the construction zone.

Trucks Will Work Around High-School Schedule

HCFCD has coordinated the contractor’s work schedule with administrators at Kingwood Park High School and Humble ISD to avoid arrival and departure times at the high school.

For More Info

If you’re tracking the progress of this on the HCFCD website, look for “Excavation and Removal Project at Former Woodridge Property” under Kingwood Information in the SAN JACINTO Watershed:

  • Project ID: G503-06-00-E002
  • Bond ID: Z-02

HCFCD also maintains Facebook and Twitter pages.

The City of Houston purchased the northern 70 acres of the site for a wastewater treatment facility. But the fate of the rest of site has not yet been decided. Community groups have reportedly been lobbying to turn the area into a wooded park with trails. A decision could come on that in the next few months.

HCFCD officials emphasized that the final dimensions of the pond could change as excavation proceeds. But dimensions should be determined long before Sprint finishes excavation.

Posted by Bob Rehak on 11/25/2021

1549 Days since Hurricane Harvey

Woodridge Village: Perry Homes’ 60 Percent Solution Now Complete

When last I checked on the status of Perry Homes’ Woodridge Village project in Montgomery County north of Elm Grove, contractors were still putting the finishing touches on detention ponds. Since then, Perry has:

  • Erected chain-link fencing with barbed wire around the perimeter
  • Planted some grass to stabilize the soil
  • Removed all construction equipment from the site.

More Than a Year After Imelda, Still No Deal

Perry is waiting to see if Harris County and the City will be able to finalize a deal to purchase the site and turn it into a regional detention basin. The three sides have been talking for more than a year. The project twice contributed to flooding Elm Grove last year after Perry cleared the land but before they built all of the required detention capacity.

Now that they’re finished though, they still have only 60% of what they need. That’s because the company rushed to get the project permitted before new, higher Atlas-14 regulations went into effect.

In February this year, the City declined to consider purchasing Woodridge Village. The City said it was the County’s responsibility because voters passed a flood bond, even though the City had approved Perry’s plans even before LJA’s drainage analysis had been submitted.

Harris County has subsequently tried to buy the land and build more detention capacity since April. But Precinct 1 Commission Rodney Ellis has heaped new conditions on the sale every time the sides seem close to reaching a deal. Commissioners finally voted to approve negotiation of an earnest money contract in September. But then, at the October 27 Commissioners Court Meeting, Ellis hinted that he now wants the City to apply his “equity” standards to its own flood mitigation projects. “I’m going to propose that they give us a recommendation or I’ll come up with one, he bragged. Or threatened.

In the meantime, Perry Homes hinted to Elm Grove leaders that, “It sure would be nice if all those lawsuits went away.” Perry Homes also still has a “For Sale” sign up on the property, although the listing company does not show the property on their website.

Entrance to Woodridge Village from Woodland Hills.

This all reminds me of a line from one of my favorite movies. “Once the plan gets too complex, everything can go wrong.”

Walter Sobchak in Big Lebowski

At this rate, the 60% solution may stay the 60% solution for a long time. Certainly, the lawsuits show no sign of going away any time soon. The Harris County District Clerk’s website (see CAUSE NO. 2019-33415) has seen a flurry of filings in recent months.

Current Pics

Here’s how the site looks today.

Looking east over S1 towards S2, the two detention ponds on the southern border of Woodridge Village.
Looking north along the eastern border toward N3, the third pond on the northern section.
Where the northeastern portion of the site drains into the head of N3. Note security fence around perimeter.
Looking south along N3 toward Taylor Gully in the background.
Looking east along the northern border toward Ford Road in Porter.
Looking west along the northern border
Looking southwest across the northern portion of Woodridge Village, with N3 on the left.
N1, the first detention pond on the northern section of Woodridge Village
The massive N2 pond along the southwestern border of the northern section.

The detention ponds passed several minor tests last spring and summer, but have yet to see a major challenge.

Posted by Bob Rehak on 11/9/2020

1168 Days since Hurricane Harvey and 417 since Imelda

Woodridge Village Detention Ponds Pass Another Test

Back on June 25, 2020, the Woodridge Village detention ponds passed their first modest test when they retained a 2.32-inch rain that fell in a little more than an hour. The mostly excavated, but not-quite-finished ponds eroded badly, but no one in Elm Grove or North Kingwood Forest flooded. Then came Beta.

Design Capacity of Detention Ponds

LJA Engineering designed the Woodridge Village detention ponds to hold only a 12-inch rain in 24 hours. And the night before the storm, forecasters predicted Beta could drop 12 inches in the Lake Houston Area. Beta had already dumped 15-inches just a few miles south. All this created high anxiety. But in the end, the Lake Houston Area received less rain.

Elm Grove resident Jeff Miller measured just 5.5 inches in his rain gage – well within the theoretical design capacity of the detention ponds. But that was almost exactly the amount that flooded Elm Grove on May 7, 2019.

Ponds 40% Short of Atlas-14 Requirements

On top of that coincidence, other factors contributed to the anxiety felt by residents. LJA did not design the ponds to meet new Atlas-14 rainfall requirements; they’re 40% short. Nor did LJA acknowledge floodplains or wetlands on the property when they calculated detention requirements. All of these factors contributed to flooding Elm Grove last year and called LJA’s ethics into question.

So it was a welcome relief when the people of Elm Grove rolled out of bed Wednesday morning to find they didn’t flood.

How Well Did Ponds Perform?

Here’s what the ponds looked like after about five to six inches of rain. All photos were taken shortly after Beta’s rain stopped on Wednesday, 9/23/2020.

Looking north at N3 Detention Pond along eastern border of Woodridge Village where it joins the east-west portion of Taylor Gully. Note pond is a little less than half full, not surprising for a rain that was a little less than 50% of the design capacity.
Likewise, the massive N2 detention pond on the western border was less than half full.
Looking SE across the empty N1 pond on the western border. It had already drained into N2.

Two Failures in N3 Pond

However, there were two failures, both in the N3 pond. Neither was mission critical.

Water could not get into N3 without overflowing the edge of the pond, causing erosion. Stormwater seems to want to collect here. This same area eroded badly in a previous storm.
In a second place along N3, erosion blew out the entire western wall.

Overflow Spillway Apparently Not Used

The overflow spillway at the county line between the concrete lined channel and the S2 detention pond was apparently not needed during Beta. There were no signs of erosion (see below) that were present after previous floods.

Rain was spread out enough that it appears water from Taylor Gully and N3 stayed in the concrete-lined channel rather than using the emergency overflow spillway that leads back into the S2 detention pond (right) and the twin culverts.

Nevertheless, despite recently planting grass along the banks of the ponds, Perry Homes still has a significant erosion problem. Note the color of the water in Taylor Gully at the top of the image above. The company is redepositing silt in the ditch, which HCFCD just cleaned out.

Living Under the Threat of Bad Planning

A big test of these ponds will be a 12-inch rain. If the ponds can successfully detain that much rain without flooding Elm Grove, we will know they at least function as planned…despite their 40% shortfall in capacity.

But the ultimate test will be when we get a larger rain. LJA Engineering and Perry Homes did NOT design them for that.

Unless Harris County and the City can piece together a deal to buy this property and build more detention, residents could flood again. The real disaster scenario here could be the purchase deal falling through. If Perry or some other builder develops this property, downstream residents will forever live under the threat of that 40% shortfall.

Posted by Bob Rehak on 9/24/2020 with thanks to Jeff Miller

1122 Days since Hurricane Harvey and 371 since Imelda

The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.