Tag Archive for: Taylor Gully

Public Comment Period on Taylor Gully-Woodridge Village Plan Open to December 28

Last night, Harris County Flood Control District (HCFCD) revealed its long-awaited recommendations to reduce flood risk along Taylor Gully. The recommendations involve channel improvements, another Woodridge Village stormwater detention basin, and a new bridge at Rustling Elms.

HCFCD is seeking public comment on the plan through December 28, 2022.

Outline of Recommended Alternative

Excessive runoff from Woodridge flooded hundreds of homes in Elm Grove, North Kingwood Forest, and Mills Branch twice in 2019 after a developer clearcut 270 acres without sufficient mitigation.

To fix the problem, HCFCD examined four different alternatives outlined in this presentation, but recommended Option 1. It includes building:

  • A concrete-lined, low-flow channel within the existing channel to expand conveyance from 350 feet downstream of Creek Manor Drive to 1500 feet downstream of Mills Branch Drive. The concrete portion would be four feet deep and 20 feet wide.
  • An additional dry-bottom, 412.5 acre-foot detention basin on the northern portion of the site.
  • A new clear-span bridge at Rustling Elms to replace the current bridge over two culverts.
Four-foot-deep, 20-foot-wide concrete channel-in-a-channel (not drawn to scale) would expand conveyance without expanding current width of main channel.
Scope of recommended alternative. Does not show work on E&R contract already underway or replacement of Rustling Elms bridge. But those would be included.

The recommended alternative would not require any right-of-way acquisition. Translation: no buyouts required.

166% Increase In Stormwater Detention Capacity

Not shown in the diagram above is the stormwater detention basin that Sprint Sand and Gravel is currently working on. Under the terms of their excavation and removal contract with HCFCD, the contractor has up to three years to excavate 500,000 cubic yards. A spokesperson for HCFCD said, “We expect that they will excavate the full amount. The E&R area, like the existing Perry Homes basins, will eventually connect to or become part of the Woodridge detention-basin network to complement the recommended alternative.”

Five hundred thousand cubic yards equals 309 acre feet. With the new pond, that would add 721 acre-feet of stormwater detention to the existing site. The site currently has 271 acre feet of detention. So, the detention volume would increase 166%. It only needed to increase 40% to meet Atlas-14 requirements. Net: the recommended fix should create a considerable margin of safety.

Not Included in Recommendations

The plan does NOT include any improvements near White Oak Creek at the downstream end of Taylor Gully. HCFCD determined that flooding at that end of the channel was caused by backup from White Oak and Caney Creeks.

Area circled in red floods from water backing up from White Oak Creek, not Taylor Gully.

However, discussion during the meeting suggested that the recommended detention basins further upstream on Taylor Gully could help that area to a minor degree. The plan primarily addresses flooding along and either side of the channel highlighted above to the left of the red circle.

Bridge Replacement

Because of the concrete-lined, low-flow channel conveyance improvements that are a part of the recommended alternative, the existing culverts at Rustling Elms Drive (below) would need to be replaced. See below. An open-span bridge like the one in the background would likely replace it. The current bridge built over culverts (below) backed water up considerably during the 2019 floods and contributed to flooding homes for several blocks on either side of it.

Rustic Elms Bridge on Taylor Gully
The bridge at Rustling Elms (foreground) caused backups after Woodridge was clearcut. This would be replaced.

Comparison of Alternatives

HCFCD recommended Alternative #1 because it removes the most structures, acres and roadway from the floodplain for the second lowest cost. Compare the alternatives below. For a fuller description of each alternative, including those not recommended, see the complete presentation.

Alternative #1 is recommended.

What Comes Next?

The sequence below outlines project steps. We are currently discussing the preliminary engineering phase. After public comments have been incorporated in that report, HCFCD will deliver it to commissioner’s court and begin final design.

After close of public comments, they will be incorporated into plan transmitted to Commissioners Court.

Then, the final design will begin for all improvements. Once complete, the final design will dictate final costs and timing.

To View Video of Meeting and Comment…

HCFCD wants your input. To review the hour-long video of the meeting and/or submit a public comment, see this page (F-14 Taylor Gully Flood Risk Reduction Project).

Review the entire presentation here.

Posted by Bob Rehak on 12/15/22

1934 Days since Hurricane Harvey

Last Reminder: Taylor Gully Meeting Wednesday 6:30 p.m.

Harris County Flood Control District will hold a virtual Taylor Gully meeting Wednesday, December 14, 2022 at 6:30 p.m. Purpose: to discuss the findings of its plan to reduce flood risk along Taylor Gully. Register at: PublicInput.com/taylor.

To learn more about the project scope, see this post. It discusses the related effort to virtually double detention capacity on the Woodridge Village Property that HCFCD purchased in 2021. Up to six hundred homes flooded in this area twice in 2019.

About Taylor Gully

The headwaters of Taylor Gully originally started where Woodridge Village is today, just north of the Harris/Montgomery County Line (tan area in map below). From there, it cuts through Elm Grove, Mills Branch and Woodstream Forest before joining White Oak Creek which then joins Caney Creek and the East Fork San Jacinto.

Taylor Gully/Woodridge Village
Project being discussed Wednesday night

Taylor Gully Meeting Details

The virtual community engagement meeting will be held on:

December 14, 2022, 6:30 p.m. – 7:30 p.m. 
Register/Join online at: PublicInput.com/taylor
Or join by phone* at 855-925-2801 with Meeting Code: 3364

The Taylor Gully meeting will begin with a brief presentation to share project updates, followed by a moderated Q&A session with Flood Control District team members. Residents will be able to submit questions, comments and input before, during and after the meeting, which will be considered during project development. Any comments not addressed during the Q&A session will receive a response at the conclusion of the public comment period.

Meeting Followup

Even if you are unable to attend the live meeting, residents are encouraged to register for the meeting to receive future project updates. A recorded version of the meeting will be available on the Flood Control District’s website and YouTube channel after the event. 

Special Needs?

Meeting accommodations can be made for those with disabilities. If needed, please contact 346-286-4040 at least three business days 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/taylor.

Posted by Bob Rehak on 12/13/22

1932 Days since Hurricane Harvey and 1181 since Imelda

Save the Date: HCFCD Releases Details of Taylor Gully Meeting

On Dec. 2, I printed a story about an upcoming virtual community meeting on Taylor Gully. At the time, Harris County Flood Control District (HCFCD) had not yet released details yet on how to attend. They have now. See their press release below. Please share it with family, friends and neighbors if you live anywhere along Taylor Gully. That includes parts of Sherwood Trails, all of Elm Grove, all of North Kingwood Forest, parts of Mills Branch, Woodstream Forest, and even parts of Porter in Montgomery County. Yes, plans will affect Porter also.

Map of Project

Map of project from HCFCD.org

Virtual Community Engagement Meeting for the
Taylor Gully Flood Risk Reduction Project

HCFCD PROJECT G103-80-03.1-E001

BOND PROJECT F-14

The Harris County Flood Control District will hold a community engagement meeting for the Taylor Gully Flood Risk Reduction Project. The purpose of this meeting is to inform residents about the project’s status, share project information and gather important community input on this effort.

The Taylor Gully Flood Risk Reduction Project focuses on improvements to Taylor Gully and the mitigation required to build the project. This project will be partly funded through the 2018 Bond Program, which was approved by Harris County voters on August 25, 2018. Community engagement is a foundational component of the Bond Program, and we invite your participation and input as projects are implemented.

Register Now

The virtual community engagement meeting will be held on:

December 14, 2022, 6:30 p.m. – 7:30 p.m. 

Join online at: PublicInput.com/taylor

Or by phone* at 855-925-2801 with Meeting Code: 3364

The meeting will begin with a brief presentation to share project updates, followed by a moderated Q&A session with Flood Control District team members. Residents will be able to submit questions, comments and input before, during and after the meeting, which will be considered during project development. Any comments not addressed during the Q&A session will receive a response at the conclusion of the public comment period.

Even if you are unable to attend the live meeting, residents are encouraged to register for the meeting to receive future project updates. A recorded version of the meeting will be available on the Flood Control District’s website and YouTube channel after the event. Meeting accommodations can be made for those with disabilities. If needed, please contact 346-286-4040 at least three business days 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/taylor.

Esta reunión de participación comunitaria se llevará a cabo en inglés; sin embargo, el Flood Control District proporcionará intérpretes de idiomas y materiales traducidos a pedido. En caso de necesidad, comuníquese al 346-286-4040 al menos tres días hábiles antes de la reunión.

*If you attend by phone only, maps and other exhibits will not be visible. However, information will be available after the meeting on the project webpage at hcfcd.org/taylor.

Posted by Bob Rehak on 12/8/2022 based on a press release from HCFCD

1927 Days since Hurricane Harvey and 1176 since Imelda

Taylor Gully-Woodridge Village Meeting Scheduled for Dec. 14

The Harris County Flood Control District (HCFCD) has scheduled a community meeting to reveal the results of an engineering study of the Taylor Gully watershed and Woodridge Village, the aborted development that flooded Elm Grove and North Kingwood Forest twice in 2019. The virtual meeting will be on:

  • December 14, 2022
  • 6:30 PM – 7:30 PM

Two Related Efforts

Because Woodridge Village sits at the headwaters of Taylor Gully, the volume of stormwater detention upstream and the amount of conveyance needed downstream are related. More of one could mean less of the other. HCFCD has been working to find the optimum solution, which should be discussed at the meeting.

Areas of Concern Identified by Community Members

Community members previously expressed concerns, including:

  • Bringing stormwater detention capacity on the Woodridge Village site up to Atlas-14 standards.
  • Straightening a Taylor Gully oxbow adjacent to Woodstream Forest where numerous homes flooded.
  • Replacing the old culvert-style bridge on Rustic Elms with an open-span bridge.
Rustic Elms Bridge on Taylor Gully
The Rustic Elms Bridge on Taylor Gully has a twin-culvert design with less conveyance than more open bridges like the one at West Lake Houston Parkway farther downstream in this image. Nearly every home behind this bridge on adjacent streets flooded in 2019.

Hundreds of homes adjacent to Woodridge Village and Taylor Gully flooded twice in 2019 after a developer clearcut approximately 270 acres before building required stormwater detention basins.

The developer then sold the troubled project to HCFCD in March 2021 after building 271 acre feet of stormwater detention capacity – an amount sufficient to meet Montgomery County’s pre-Atlas-14 standards, which were in effect at the time of permitting.

Taylor Gully One of Top Two Priorities in Kingwood Area

The Kingwood-Area Drainage Analysis from October 2020 recommended Taylor Gully as one of the top two priorities for Kingwood. However, HCFCD also recommended the Taylor Gully project be re-analyzed to determine how the use of Woodridge Village for detention could modify the recommended plan.

Here is the scope of work for the engineering company that worked on the Taylor Gully-Woodridge Village project.

42 More Acre Feet Removed to Date from Woodridge Village

In March 2021, Harris County and the City of Houston purchased the Woodridge Village property. They then started an Excavation and Removal Contract with Sprint Sand and Clay in January 2022 that could ultimately double the volume of stormwater detention on Woodridge Village.

Since February 2022, Sprint Sand & Clay has removed an average of more than 1,700 cubic feet of dirt each week from Woodridge. That’s roughly one acre foot per week. An acre foot equals 1613.33 cubic yards of material.

So, HCFCD has increased detention capacity by almost 42 acre feet since signing the contract with Sprint. That means detention capacity has already increased by about 16 percent, not quite half of what it needs to meet new Atlas-14 requirements.

Stats from HCFCD show cubic feet of dirt removed from Woodridge Village by Sprint Sand & Clay each week since start of E&R contract.

Pictures Showing Woodridge Village Status

Here are some pictures that show the extent of excavation on November 26, 2022.

Looking NE along Harris/Montgomery county line (tree line on right).
Close-up shot of active work area.
Looking S toward Sherwood Trails Village

Excavation and removal contracts give HCFCD a head start on construction of stormwater detention basins. The final dimensions may not be known yet, but HCFCD can make adjustments as it finalizes construction plans.

We should learn more about those on December 14th. Block out the date for the Taylor Gully, Woodridge Village meeting.

Posted by Bob Rehak on 12/2/2022

1921 Days since Hurricane Harvey

Woodridge Village Excavation, Taylor Gully Updates

Harris County Flood Control District (HCFCD) says that, as of 10/31/22, Sprint Sand and Clay has hauled off 66,094 cubic yards of dirt from Woodridge Village. That means, despite the slowing real estate market, that the company has exceeded its Excavation and Removal contract minimum within nine months of the first year.

Objective of Excavation

The objective of the contract: to get a head start on the removal of up to 500,000 cubic yards of dirt from what will eventually become the sixth stormwater detention basin on the Woodridge Village property. Woodridge forms the headwaters of Taylor Gully.

The Woodridge property flooded up to 600 homes in Elm Grove and North Kingwood Forest twice in 2019. That happened after the a developer clearcut the property before installing sufficient stormwater detention capacity.

Since then:

Community Meeting Will Reveal Findings of Engineering Study

HCFCD is now planning a community meeting to share the results with affected residents before the end of the year.

It’s not clear yet exactly:

  • How much additional detention Woodridge will need
  • How much channel widening Taylor Gully will need
  • Whether any bridges need to be replaced
  • How upstream improvements will affect residents farther downstream.

The preliminary engineering report should address all those questions.

Photos from September and October

In the meantime, a parade of dump trucks visits the Woodridge site most days to haul off dirt from where the sixth basin will go. The sixth basin could double stormwater detention capacity on the site – if Sprint excavates all 500,000 CY.

As of mid-September 2022, Sprint Sand and Clay had removed 57,785 cubic yards (CY). Currently, they have removed a total of 66,094 CY. That means they removed 8,309 CY in the last 6 weeks. And that in turn means the current monthly rate is about 5500 CY.

Sprint’s contract calls for them to remove a minimum of 60,000 cubic yards per year or 5,000 per month.

The September and October pictures below show how far Sprint has come in the last six weeks.

Woodridge Village E&R contract progress end of September 2022
End of September 2022
End of October. Sprint has not gone much farther, but they have gone deeper.

See pictures taken below from the reverse angle. The majority of the work now takes place at the far end.

Extent of excavation on September 24.
End of October 2022.

Groundwater appears to be seeping into excavated areas.

HCFCD did not confirm WHY Sprint appears to be digging shallower. Amy Stone, a HCFCD spokesperson, did say however that the site contains multiple types of soil. The volume removed in a particular location may relate to demand for a particular type.

More news about the community meeting and study findings when it becomes available.

Posted by Bob Rehak on November 1, 2022

1890 Days since Hurricane Harvey

New Woodridge Village Detention Basin About 12% Excavated, Engineering Study Almost Done

A new Woodridge Village Stormwater Detention Basin that could almost double detention capacity on the site continues to move forward slowly as housing starts slow. The trend at Woodridge seems consistent with other excavation and removal (E&R) contracts countywide.

Meanwhile, the first draft of a preliminary engineering study for the Woodridge site and Taylor Gully is complete and going through management review at Harris County Flood Control District (HCFCD).

Status of E&R Contract on Woodridge Village Site

As of mid-September 2022, Sprint Sand and Clay had removed 57,785 cubic yards of dirt from a planned detention basin on the Woodridge Village property in Montgomery County. Sprint is working under an E&R contract with HCFCD. The contract calls for them to remove up to 500,000 cubic yards at a minimum of 60,000 cubic yards per year or 5,000 per month.

Looking NE across new basin. Last month, it extended as far as the middle of the far pile of concrete pipes on the right.

So the company, which began work in February, has virtually met its first year minimum after eight months. However, the rate has slowed somewhat in recent weeks as housing starts have slowed due to a rise in interest rates. In the last four weeks for which totals are available (8/22/22 – 9/18/22), Sprint has removed only 3,045 cubic yards. To date, that brings the total excavated to 12% of the contract max.

Housing starts in the South have been especially hard hit. According to the Census Bureau, starts in August fell 13.5% compared to July and 15.4% compared to a year ago. That depresses demand for fill dirt and makes it harder for Sprint to find buyers for it.

Under the terms of its HCFCD E&R contract, Sprint gets only $1,000 for removing up to 500,000 cubic yards, but has the right to resell all the dirt at market rates. That’s how it makes its profit.

Woodridge Vs. Countywide Data

To see whether Woodridge was an anomaly or part of a trend countywide, I asked HCFCD to show readers the bigger picture. Alan Black, Deputy Director of Engineering and Construction supplied the data below. The chart shows the trend in all HCFCD E&R contracts countywide going back 10 years.

Source: HCFCD via FOIA Request

All data is open to interpretation. But I see three main “regions” in the chart above.

  • The first is pre-flood bond – before August 2018. With the exception of a few blips, excavation remained below 5,000 cubic yards per month. That’s roughly equal to the average being removed from Woodridge Village each month.
  • The second is a huge spike that occurred after flood-bond approval. it peaked at almost 35,000 cubic yards per month as HCFCD readied engineering studies on more than 180 projects countywide.
  • Third, HCFCD had a sharp falloff at the start of the pandemic in January 2020. After things stabilized, we see a gradual rebuilding. It coincides with a housing boom and is followed by another gradual drop-off. The latter coincides with rising interest rates and falling housing starts.

Regardless, the trend in the last few months does not bode well for those concerned about finishing the new Woodridge Stormwater Detention Basin quickly.

Looking W. The new Woodridge Village stormwater detention basin at the top of the frame could eventually fill most of the area between the road on the left and the ditch on the right.

Status of Preliminary Engineering Study on Taylor Gully

We should remember, however, that HCFCD always intended the Woodridge E&R contract as a head start on excavation while IDCUS finished its preliminary engineering study on Taylor Gully and Woodridge Village. The study began in mid-2021. IDCUS had 300 days to complete it.

IDCUS submitted the first draft of its results several months ago.

Amy Stone, HCFCD spokesperson

Since then, HCFCD staff has reviewed it and asked IDCUS to take a closer look at some areas, said Stone. At this point, the revised draft is working its way up to HCFCD top management for final review and comment. HCFCD has started preparing a presentation for all those affected in the area and exploring the best dates for a community input session.

Assuming HCFCD management doesn’t ask IDCUS for more revisions, we should know recommendations and next steps this fall. Following a public comment period, more changes may need to be made to engineering plans before design and construction start.

Folks who flooded in Elm Grove and North Kingwood Forest as well as others farther downstream in Mills Branch and Woodstream Village eagerly await the findings. More news when it becomes available.

Posted by Bob Rehak on 9/30/2022

1859 Days since Hurricane Harvey

Mitigation Update: 3rd Anniversary of First Elm Grove Flood

Back in 2019, portions of Elm Grove and North Kingwood Forest Villages flooded twice. The first time occurred on May 7th. According to Harris County Flood Control District’s (HCFCD) report on the storm, “A 30-min rate of 2.9 inches was recorded at US 59 and the West Fork of the San Jacinto River and a 1 hour rate of 4.0 inches.”

“380 structures were flooded in the Elm Grove Village subdivision and other nearby subdivisions in the northern portions of Kingwood.”

Investigation by HCFCD the following day revealed that “… the flooding was potentially caused by development upstream in Montgomery County that sent large volumes of sheetflow into the subdivisions and Taylor Gully.” This video shows the sheetflow pouring out Perry Homes’ Woodridge Village property into homes along Village Springs Drive.

Perry contractors had clearcut 267 acres without installing the required detention ponds when the rain hit.

In the three years that followed, I posted 242 reports about every aspect of that flood and a second one during Imelda. The second flood affected two to three times more homes in the same areas.

The floods triggered multiple lawsuits which Perry Homes, its subsidiaries and contractors finally settled late in 2021.

What It Looked Like

Shady Maple the night of the May 7 2019 flood
Escape. In Elm Grove on Shady Maple the night of the May 7, 2019 flood.
High water rescue
Rustling Elms Bridge in Elm Grove underwater as school bus tries to cross it.
Water in Keith Stewart's home on Shady Maple after May 7th flood in 2019.
Water rising at night in Keith Stewart’s home on Shady Maple after May 7th flood in 2019.

Catalog of Flood Mitigation Efforts

Ever since the Elm Grove floods, Harris County, HCFCD, the City of Houston, Congressman Dan Crenshaw’s team and others have worked diligently to reduce future flood risk.

On this Mother’s Day weekend, it may bring flooded families comfort to understand how far we have come. Much remains to do, but much has already been done, or at least started.

Major Maintenance on Taylor Gully

Even before the second flood, HCFCD undertook a major maintenance project on Taylor Gully to remove accumulated sediment and restore channel conveyance.

The project began in 2019. Work extended downstream to the natural portion of the channel. It finished in 2021.

Taylor Gully maintenance
HCFCD working to remove sediment buildup in Taylor Gully near the Maple Bend Bridge in January of 2021. The work began upstream near Rustling Elms in July 2019.

Kingwood Area Drainage Analysis and Taylor Gully Study

In 2019-20, HCFCD, Lake Houston Redevelopment Authority (TIRZ 10), and City of Houston teamed up to conduct a drainage analysis for all streams in the Kingwood area. A recommendation to prioritize engineering of drainage improvements along Taylor Gully (including Woodridge) came out of that study.

The Flood Control District began preliminary engineering study on the Taylor Gully improvements in 2021. HCFCD anticipates presenting results during late summer or early fall this year.

Purchase of Woodridge Village By County and City

In early 2021, the Flood Control District and the City of Houston partnered to acquire the 267.35-acre Woodridge Village property for approximately $14 million.

They closed on the purchase of Woodridge Village in March 2021.

Houston Mayor Pro Tem Dave Martin lobbied the City to purchase about 70 acres of the property.

HCFCD will use the remaining 194.35 acres of the Woodridge site for stormwater detention. That will help reduce flood risk.

Crenshaw Earmarks

Congressman Dan Crenshaw secured an earmark for $1.6 million for engineering of flood mitigation improvements along Taylor Gully. The engineering should shrink the floodplain. That will effectively remove 387 structures from the floodplain and has the potential to remove another 62.

Crenshaw also has another earmark pending for $10 million to actually construct the improvements recommended by the study.

Local groups must spend earmarks during the fiscal year in which Congress approves them. So funding can’t get too far ahead of the engineering.

Taylor Gully Preliminary Engineering Study

The Taylor Gully study will look at Woodridge in conjunction with other potential Taylor Gully improvements. However, HCFCD must perform additional preliminary engineering to further evaluate specific alternatives for Woodridge and determine the best. 

During each study, HCFCD will hold Community Engagement Meetings to present alternatives and gather feedback.

Excavation & Removal Contract

In January 2022, HCFCD began work on a Woodridge Excavation and Removal (E&R) project.

Start of the new floodwater detention basin that could double the capacity on Woodridge Village.This pond should ultimately expand beyond the lone trees in the middle of the frame near the top. Photo taken 4/30/22.

E&R projects provide a head start on the excavation process and risk reduction. They can start before the design of a stormwater detention basin. Contractors excavate a set amount of material within an agreed-upon timeframe and general area.

The excavation can also potentially provide interim stormwater storage while awaiting the design and construction of the final stormwater detention basin.

As of April 30, 2022, 36,421 cubic yards of material has already been removed from the site. See photo above taken that day. The project will remove as much as 500,000 cubic yards of soil and other material.

Woodridge will remain an active construction zone for up to three years.

Have a Happy Mother’s Day this weekend.

Posted by Bob Rehak on 5/6/2022

1711 Days since Hurricane Harvey and 1096 Days since May 7, 2019

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.

Sinkholes Often Sign of Damaged Storm Drains

Most of us have seen sinkholes. And most of us have probably given little thought to what causes them.

Retired engineer Chris Bloch, a local flood fighter, measured a 13-foot deep sinkhole near Taylor Gulley earlier this year that had become overgrown with vegetation. Working with the City of Houston and a local homeowner who first reported the problem, they found the sinkhole related to a nearby storm drain.

Bloch lowered this length of PVC pipe into the Taylor Gully sinkhole to measure the depth. Note how the hole had become overgrown with vegetation.

Other things can cause sinkholes, but in this area and in this part of the world, “storm drain gone bad” ranks high on the list of things to investigate.

Corrugated Pipe Commonly Used At Outfalls When Kingwood Built

According to Bloch, when Friendswood built Kingwood, they commonly used corrugated metal pipe (CMP) at storm sewer outfalls. CMP has an expected service life of approximately 35 years, says Bloch. And corrosion commonly causes failure at older outfalls constructed with such pipe.

For example, see the section of pipe below. This photo was taken on Ben’s Branch, not Taylor Gully, but it shows how the pipe rusted, bent, and crimped. Also look just to the right of the wooden posts, and you can even see a large hole in the pipe. It even tilts upward before it reaches the creek.

Corrugated metal pipe replaced earlier this year as part of a project to restore the conveyance of Bens Branch between Rocky Woods and Kingwood Drive. This area also developed a sinkhole near the manhole.

Taylor Gully Sinkhole One of Many In Area

Bloch frequently walks ditches looking for sinkholes to report to the City. He says he’s aware of at least five right now.

The 72-inch outfall to Taylor Gully serviced drainage area G03408-00-OUT which encompasses all of Greenriver Valley Drive and Mountain Bluff Lane as well as portions of Appalachian Trail, Natural Bridge and Echo Falls Drives. That area comprises 33.4 acres. See below.

Service area for damaged outfall encompasses 33.4 acres where several homes flooded.

The transition from a 72-inch concrete storm sewer to the 72-inch CMP outfall is at a manhole on the edge of the Taylor Gully right of way. See below.

Over the years, the CMP at the connection to the manhole failed. The earth above the failed pipe washed into the outfall and then downstream where it helped reduce the conveyance of Taylor Gully.

Repairs Started But Not Complete

The City of Houston has already repaired several storm sewers with failed corrugated metal outfalls. At least five additional storm sewer outfalls with sinkholes have been identified that have not yet been repaired.

Vegetation frequently hides the presence of these sinkholes. In addition to posing a danger to citizens walking along the banks of the drainage channels, the soil that falls into the sewer can be held up by the corrugations of the metal pipe reducing the flow capacity of the sewer, says Bloch.

Even without obstruction from soil falling into a sewer outfall, the rough surface of the corrugated metal pipe generates greater friction than smooth concrete. The friction slows the flow of storm water and reduces flow capacity which becomes critical during high intensity rains that cause street flooding.

Bloch somehow convinced the City of Houston Public Works Department to replace the damaged CMP at Taylor Gully with concrete pipe. See below.

“This upgrade in the outfall piping will significantly improve the flow capacity of the storm sewer system,” says Bloch.

Concrete pipe replaced CMP at the location of the 13-foot sinkhole on Taylor Gully. Installed by City of Houston Public Works Department after HCFCD repaired Gully.

Concrete Better for New Atlas-14 Rainfall Intensities

When Friendswood Development installed stormwater sewers in Kingwood, they met standards which applied at that time. With new Atlas-14 rainfall projections, we now understand that we should expect more rainfall. Several homes along Appalachian Trial suffered flood damage during Tropical Storm Imelda.

How to Report Sinkholes When You Find Them

As they say, it takes a village to reduce flooding. Now that you know the story behind sinkholes…

If you jog or walk along drainage ditches, exercise caution. Look out for developing sinkholes. And report them to 3-1-1 when you find them. They can pose dangers to children and even grown adults. To put that in perspective, Bloch (shown in the first photo) is more than 6 feet tall, but the sinkhole dwarfs him.

For More Information about Sinkholes

I highly recommend:

The US Geological Survey has an in-depth discussion of different types of sinkholes in different parts of the country and how each forms. This is geared toward students in science classes.

This NBC News story on YouTube has some spectacular examples of sinkholes in Florida along with easy to understand animations that show how they form.

Another 7 minute YouTube video from a series called Practical Engineering focuses on how sinkholes form. It contains both real world examples and table-top experiments that bring the processes to life.

Posted by Bob Rehak based on information and photos provided by Chris Bloch

1492 Days since Hurricane Harvey

Kingwood Diversion Ditch and Taylor Gully Preliminary Engineering Projects Begin

On June 29, 2021, Harris County Commissioners approved two contracts for preliminary engineering on the Kingwood Diversion Ditch and Taylor Gully Projects. This week, I’ve been getting reports of boots on the ground. So I grabbed my camera and went looking for activity this morning. I found a soil survey truck at Kingwood Drive next to the Diversion Ditch. I also found regular surveyors on Taylor Gully about a block south of Woodridge Village.

Both activities are among the first steps in preliminary engineering. And both are among the first steps in finding flood-mitigation solutions for a huge percentage of Kingwood’s population.

This drone shot shows the surveying crew a little more than one block south of Woodridge Village on Taylor Gully.
Looking downstream in opposite direction toward Rustic Elm Bridge out of sight around bend.
The surveyors were capturing elevations of the banks, slopes, ditch bottom, and backslope swales of Taylor Gully.

Taylor Gully Objectives and Scope

HCFCD has asked Idcus, Inc. to develop up to five conceptual alternative scenarios for modifying Taylor Gully. Alternative scenarios may include:

  • Expanding Detention On Woodridge Village Site so that no channel improvements are necessary.
  • Determining amount of detention and channel improvements necessary to ensure no adverse impact all the way to Lake Houston.
  • Finding the optimum balance between maximum flood protection and minimum construction costs.
Deliverables include:
  • Channel and basin layouts
  • Estimates of benefits for various levels of storms (100-year, etc.)
  • Right-of-way requirements
  • Cost estimates for right-of-way acquisition, engineering and construction management.
  • Performance metrics, i.e., estimated acreage of land inundation, number of structures in floodplain, number of structures flooded and miles of inundated roadway.
  • A scoring matrix to rank alternatives.
Scope of Taylor Gully Project includes the two halves of Woodridge Village outlined in gold above the ditch.

Kingwood Diversion Ditch Objectives and Scope

HCFCD hired Neel-Schaffer, Inc. for preliminary Kingwood Diversion Ditch engineering. They must:

  • Evaluate existing site conditions, previous studies, other projects that could affect this one, topography, rights-of-way, utilities, and soil surveys.
  • Evaluate existing bridges
  • Conduct and H&H analysis to assess existing and proposed conditions (from 2-year to 500-year storms).
  • Analyze Channel Improvements including the:
    • Impact of TIRZ #10’s latest design to replace the Northpark Bridge
    • Diversion structure at the confluence of Bens Branch and the Diversion Channel
    • Drop structures in lieu of a concrete lined channel to minimize high velocities due to the steep grade between 
      Walnut Lane and Deer Ridge Estates Blvd.
  • Develop phased construction plans based on available funding, potential impacts and benefits.
  • Conduct two public engagement meetings and coordinate with community groups.

Deliverables include:

  • Surveys
  • Geotechnical investigations, i.e., bridge borings
  • Environmental assessment
  • “Jurisdictional” determination. Does this channel fall under the jurisdiction of the Army Corps as it nears the West Fork? If so, channel design may need to be altered.
  • Determination of detention pond requirements
  • Exploration for subsurface utilities
  • Obtaining permits from the Corps
  • Landscape architect services
Scope of Diversion Ditch Project runs from St. Martha Catholic Church in Montgomery County to the San Jacinto West Fork at River Grove Park. This is the ditch that runs past the fire station on Kingwood Drive.

Why These Two Projects First?

Both of these projects evolved from the Kingwood Drainage Analysis finalized late last year. That study identified nine channels that needed improvement. These two were recommended for immediate help because:

  • They help the largest number of people.
  • HCFCD already owns land to expand and deepen the Diversion Ditch.
  • Diversion Ditch enhancement will immediately take pressure off Ben’s Branch, and help flooding there.

Note that Ben’s Branch has already gone through a four-phase major maintenance project designed to restore its original conveyance.

Here is Harris County Flood Control District’s Summary of Results from the 600-page Kingwood Area Drainage Analysis.

A Good Sign

Both of these projects go far beyond maintenance, which portions of both of these ditches have already received. While we’re still far from construction, the work that kicked off this week will improve flood safety for a large part of Kingwood.

Posted by Bob Rehak on 8/4/2021

1436 Days since Hurricane Harvey

Commissioners Approve Excavation Contract for Regional Detention Pond on Taylor Gully

In yesterday’s Harris County Commissioners Court meeting, commissioners unanimously approved a contract with Spring Sand & Clay LLC for excavation of a regional detention pond on Taylor Gully in Montgomery County at the Woodridge Village site.

Preliminary Engineering Began in Early July

Earlier this year, Harris County purchased Woodridge Village from Perry Homes for this purpose. Currently, engineers are examining several Taylor Gully alternatives.

Woodridge Village
Looking north across Woodridge Village toward Porter from over the Harris/Montgomery County line. The abandoned development currently has five detention ponds that will hold about 60% of the rain in an Atlas-14 100-year storm.

Currently, Idcus, Inc., an engineering company, has been contracted to look at:

  1. Whether existing detention and proposed channel improvements would suffice to mitigate flooding
  2. Whether expanding existing detention would eliminate the need for channel improvements
  3. A combination of the two scenarios above – determining the amount of additional detention and channel improvements necessary to ensure no adverse impact all the way to Lake Houston.
  4. Out-of-the-box alternatives that ensure no adverse impact while maximizing flood mitigation and minimizing construction costs.

The Idcus contract calls for the company to deliver channel and basin layouts for Taylor Gully no later than 300 days from the notice to proceed, which presumably was given in early July. However, excavation could start much sooner than that. (See below.)

Pieces of Puzzle Falling into Place

The no-cost contract with Sprint lets them set their own timetable as long as they complete improvements within three years. Sprint’s timetable will be driven by the company’s ability to sell the material they excavate; that forms their compensation.

The next step is for Harris County Flood Control District (HCFCD) to provide a grading plan to the contractor. While that will not happen tomorrow, the good news is that it won’t require waiting 300 days.

HCFCD can start excavating the retention pond before plans are finalized. After all, it’s not a problem if a detention pond holds more than the minimum required. It’s only a problem if it holds less. Engineers and contractors can adjust plans if necessary after excavation starts. This approach should minimize flood risk for worried Elm Grove and North Kingwood Forest residents.

All the pieces of the puzzle are starting to fall into place.

Posted by Bob Rehak on 7/21/2021

1422 Days since Hurricane Harvey