Tag Archive for: Woodridge

Even More Discoveries Demand Independent Investigation into Causes of Flooding Around Woodridge Village

On 8/28/2018, LJA Engineers’ project manager for hydrology and hydraulics, submitted a 59-page letter to the Montgomery County Engineer’s Department. The subject: Figure Four Partner’s proposed Woodridge Village development. It shows that the developer knew of the potential for downstream flooding, yet did not develop the site in a way that might have prevented or reduced flooding.

Specifically, the developer’s team failed to construct needed detention ponds in a timely manner. They could have helped offset the effects of clearcutting the southern section of land. Instead, the contractor continued clearcutting the northern section, filled in existing drainage, and sloped land toward Elm Grove BEFORE installing needed detention ponds.

The contractor also failed to repair a culvert running next to North Kingwood Forest. Engineers warned that the damaged culvert had to be replaced.

Finally the engineers may have mischaracterized the soil in modeling assumptions. They classified soil as sandy loam instead of clay. That could have skewed a key factor in runoff models by 2X to 3X.

Parts of Porter Also Flooded That Were Not in Any Recognized Flood Zone

LJA’s letter also shows that residents who flooded in Porter on the western edge of the new Woodridge development were NOT in either 100-year or 500-year flood zones. This supports the claims of Porter flood victims, such as Gretchen Dunlap-Smith. They say they never flooded before. They also claim that Rebel Contractors pushed dirt up against the western edge of the development while filling in natural drainage and wetlands. These actions likely constrained drainage on May 7th, before the contractor began installing storm sewers, drainage ditches and detention ponds in that area.

Flood Plain Maps Show What Developer’s Team Knew Before Permit Granted

Section 1.5 of LJA’s letter to Montgomery County states, “The project site is shown on FEMA Flood Insurance Rate Map (FIRM) panel 48339C0750H for Montgomery County, Texas and Incorporated Areas, revised August 18, 2014. The area just across the county boundary from the project site is shown on FIRM panel 48201C0305L for Harris County, Texas and Incorporated Areas, revised June 18, 2007.” On Page 51, the letter shows existing floodplains on the map below.

Page 51 from LJA letter to Montgomery County Engineer. The dark purple lines show the boundaries of the new development. The light purple and gray areas below the new development show the 100-year and 500-year flood plains in Elm Grove, North Kingwood Forest, Mills Branch and Woodstream Villages.
Drainage on the developer’s two tracts is sloped toward Taylor Gully, Elm Grove and North Kingwood Forest in red circle.

Clearcutting of the S2 detention pond area finished last November according to Nancy Vera of Elm Grove. However, only detention pond S1 and the flow-restricting box culvert next to Vera’s house had been substantially completed by May 7. Neither N1, nor the drainage ditch connecting it with N2 were excavated on May 7th; they still have not been excavated.

At the time of the May 7th flood, only detention pond S-1 had been installed. N-2 is on land owned by Montgomery County and was at least partially excavated in 2006, but none of the devices regulating flow into or out of it had been installed on May 7th.

LJA Engineering’s models assumed all the detention ponds are in and functioning, but we know they were not at the time of the flood. Instead of installing drainage first, the contractor focused on clearcutting and grading the northern section of land which exacerbated flooding on the southern section.

Drain Pipe Should Have Been Replaced

Page 3-1 of the LJA Letter mentions, “…an existing 36-inch-diameter x 290-foot HDPE culvert in Taylor Gully at the downstream end of the project. The upstream end of the culvert is within Montgomery County and the downstream end is within Harris County. Because of its poor structural condition, this culvert needs to be replaced.”

Intake end of the pipe referenced on page 3-1 of LJA Engineer’s letter to Montgomery County. Photo taken on May 12, 2019.

Judging by the poor condition of the pipe after the May 7th flood and the lack of disturbed soil around it, I feel it’s safe to say that it wasn’t replaced at the time of the flood.

Modeling May Have Included Faulty Assumption About Soil

Every time I re-read the letter to Montgomery County, new things jump out at me in light of new things I have learned. Today, I spotted another huge and potentially faulty assumption relating to runoff and flooding. The site description on page 1.1 states that the project site is “characterized by fine, sandy loam.” One of the oil industry’s leading geologists, however, characterized it as “mostly clay,” though he did say it became more sandy in natural drainage features, such as stream beds.

Major factors affecting the runoff coefficient for a watershed are land use, slope, and soil type. We know the contractor increased the runoff rate when it clearcut the forest and altered the slope of land. But I had not previously focused on how the engineers characterized the soil type, which affects water infiltration.

  • Sandy soils absorb more rain, generally reducing runoff.
  • Soils with more clay absorb less rain, generally increasing runoff.

In modeling runoff and flooding potential for Woodridge Village and downstream areas, LJA Engineers used the Army Corps’ Hydrologic Modeling System (HEC-HMS). Page 216 of the user guide for that program states that, “The sand percentage accounts for the effect of infiltration and surface runoff properties on hydrograph generation. Zero percent indicates essentially all-clay soils with characteristically low infiltration rates. Conversely, 100 percent indicates essentially all-sandy soils with characteristically high infiltration rates.”

BrighthubEngineering.com estimates infiltration rates in inches per hour for different types of soil. They show the rate for clay-based soils to average one-third to one-half the rate for sandy loam. That means…

The characterization of the soil could have skewed this component of LJA’s modeling by 2X to 3X. Certainly, that merits further investigation and verification of LJA Engineering’s results before contractors begin pouring concrete.

New Discoveries Argue for Independent Engineering Investigation

All of these observations argue for an independent investigation into the engineering of and construction practices on this site. They raise serious questions about the accuracy of LJA’s conclusions and whether their plans will protect downstream residents from future flooding.

Let’s pray that Montgomery County and the City of Houston commission a forensic investigation into the causes of this flooding. That’s the only way we’ll be able to prevent similar flooding in the future. By the time these issues work their way through the court system, contractors will have built homes and streets that could forever alter downstream flood potential. Harris County and the Federal government could be stuck with hundreds of buyouts costing tens of millions of dollars. A second opinion might save a lot of heartbreak, misery, and tax dollars. Better safe than sorry.

Posted by Bob Rehak on 6/2/2019

642 Days since Hurricane Harvey

The thoughts in this post represent my opinions on matters of public policy and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP statute of the great State of Texas.

Woodridge Problems Still Piling Up for Porter Resident Chris Yates

Photo looking west toward Yates property just out of frame on right. Developer continues to build site up relative to neighbors – before installing drainage. This has created problems for Chris Yates and his neighbors in Porter.

Some more bad news surfaced today for the people whose drainage has been affected by Woodridge Village construction activity. Rebel Contractors has built up the level of Woodridge before installing drainage between Woodridge and neighbors. As a result, water has ponded in Porter yards for months and damaged their property. Then, to add insult to injury, about a week after finally erecting a long-awaited silt fence, Rebel Contractors covered it with dirt.

Woodridge: The Yates Family Curse

Chris Yates, who lives at 25395 Needham Road in Porter, sent me these pictures today. They show how construction activity has affected his property. First up: two BEFORE shots showing his happy family in front of the Woodridge site.

Yates’ daughter Amber in back yard before clearcutting began. Looking east. A small ditch ran through the tree line which forms the property line between Yates and Woodridge. Note the telephone lines at the top of the picture for reference in subsequent photos.
Yates with family in happier times. This was taken after construction began but before water started piling up. Note piles of dirt being stacked up on Woodridge property in background.
After clearcutting and grading of the Woodridge property in the background, water started collecting in Yates’ yard. This rain fell in March and remained there until Friday, May 31, when Yates pumped it out.

Contractor Should Have Maintained Positive Drainage at All Times

Page 6/Point 12 of the Woodridge Village Detention Plan states that, “Contractor shall maintain positive drainage from construction site at all times. Any damage to existing ditch system as the result of the contractor’s activities shall be repaired to existing or better conditions.” Oops! Neighbors up and down the western border of Woodridge have experienced stagnant water. Some have even experienced flooding.

Almost 4 Feet of Standing Water Before Any Drains Away

The Yates back yard on May 7. Their four-foot fence is barely visible in these two shots taken as water built up. It could not drain away according to Yates until the stormwater crested at a high point to the south between his home and Sherwood Trails..
This recent shot shows how the standing water killed Yates’ grass. Silty runoff ponded for two months.
Today, Yates pumped the water out to his street drain. It took him eight hours, pumping at 3,700 gallons per hour. While this kind of damage does not compare to the loss of a home, I’m sharing this story because it seems to illustrate the contractor’s disregard for the problems it causes neighbors.
Yates raises several animals on his property but has had to keep them caged for months because of the standing water.
Detention plans show that developer knew runoff was moving west to east toward development.
Page 12 of the Water, Sanigtary Sewer and Drainage Facilities & Paving Appurtenances Plan shows that developer was expecting to compensate for 10-aces of offside drainage from the Yates neighborhood, but didn’t start installing the storm drains for months, until well after three heavy May rains.
Looking north from Yates back yard along western boundary of Woodridge. Note the standing water between development and neighbors. The Woodridge side of the property (right) was elevated approximately 3 feet before drainage was installed. Photo taken 5/31/2019.
Plans show that this drain should eventually handle water that collects between Yates’ property and Woodridge. Question: Why wasn’t this installed before the Woodridge property was elevated? Said Yates who has years of construction experience, “Drainage is put in by elevation so this could have been put in before building up.” Photo taken 5/31/2019.

More Out-of-Sequence Construction?

Yates, whose father owned a clearing/grading business, worked in the family business when younger and said that on a site like this, they typically installed drainage first thing. The reason: ponding water slows down construction. “Even though it takes time, it saves time,” said Yates. “You can’t work when the site is wet. Construction on this site seems to be out of sequence.”

Yates also said that he had talked to the developer and learned they were six months behind schedule. One can only wonder whether the delayed installation of drainage had anything to do with the construction delays.

This sequencing complaint echoed the concerns of Elm Grove and North Kingwood Forest residents. They flooded, in part, because the developer clear cut the entire 268 acres before installing critical detention ponds.

The Silt Fence Saga: Part 2

This and detention ponds were not the only out-of-sequence construction that neighbors have suffered through. Silt fences should have been installed before clear cutting started. Instead, they were put up almost a year later.

Additionally, the developer finally installed silt fences last week. The developer was supposed to install them before clearcutting began. For months, residents complained about sand, silt and clay pouring out of the construction site into streets and storm drains. Then about a week or so ago, after a complaint to the TCEQ triggered an investigation, silt fences finally appeared. Now they are buried under dirt again.

1-2 Week old silt fence … buried under silt. Said Yates, “What’s the point of silt fences if you are piling dirt on top of them an on the other side of them?” Photo taken 5/31/2019.

Chris Yates must feel at this point as though he’s Rodney Dangerfield. “Can’t get no respect.” Let’s hope he and the hundreds of other families affected by Woodridge construction find some before this is all over.

Posted by Bob Rehak on 6/1/2019 with images courtesy of Chris and Tammy Yates of Porter

641 Days since Hurricane Harvey

All thoughts expressed in this post are my opinions on matters of public policy and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP statute of the Great State of Texas.

More on What Went Wrong Near Elm Grove and How to Help Protect Residents from Future Flooding

Map by LJA Engineering shows natural drainage. Purple outline shows boundaries of Figure Four Partners’ Woodridge Development. Dark gray outline shows extent of drainage area for Taylor Gully. All drainage in A-E flows to F.

According to residents in Elm Grove and North Kingwood Forest, their homes never flooded before May 7th, 2019, including during Hurricane Harvey. Then bulldozers cleared the 262 acres north and west of them to create a new subdivision called Woodridge Village.

Reconstruction of Events

After talking with dozens of residents, mapping flood damage, reviewing flood videos, and photographing the aftermath, I think the following happened on May 7, 2019.

Before May 7th, contractors had finished clearing most of Woodridge Village’s 268 acres, most of which was hard clay. This accelerated runoff. They had also begun grading the land, filling in historical drainage channels and wetlands. But they had not yet totally completed any of the replacement drainage, even though one pond was substantially completed.

A large, long, linear ditch ran along the county line. Approximately half of this ditch (labeled S1 by the developer) bordered Sherwood Trails. Contractors had fully excavated the ditch but not fully finished it. The other half of the ditch that bordered Elm Grove did not yet have:

Red labels and circle have been added to approved drainage plan to make it easier to follow this discussion. Small black arrows indicate direction of flow. The 29-acre triangular area labeled N2 actually belongs to Montgomery County, which started cleared most of the land between 2006 and 2008.

Here’s an enlargement of the crucial S2 detention area that shows the flow. All water from the northern section of Woodridge, drains to the part of Taylor Gully running from the triangular detention area N2 on the left toward the upper right.

Note two u-turns made by the water within the space of 200 feet.

Several things happen when the water reaches the upper right.

  • Most of the runoff is forced to make a 120 degree right turn.
  • It’s joined by more water flowing south along the eastern edge of the property to the north, and the gas pipeline easement north of North Kingwood Forest.
  • All of that flows into a much smaller ditch…
  • …that narrows down into a 3′ pipe…
  • At that point, it is supposed to make another 90-degree turn into…
  • …a grassy-lined channel that conveys the water into S2
  • …where it mixes with stormwater from S1…
  • …and flows through a box culvert…
  • …into Taylor Gully where it’s joined by water shooting out of the 3′ pipe.

Here’s an even closer view of how all that works.

The Big Lebowski Connection

In the movie The Big Lebowski, Walter says to The Dude, “That’s right, Dude, the beauty of this is its simplicity.  Once the plan gets too complex everything can go wrong.” And it did.

Of course, it was complicated by the facts that:

  • Most of S2 had not yet been excavated.
  • The grassy-lined channel to convey water from the upper part of Taylor Gulley into S2 had also not yet been excavated.
  • A reinforced concrete box culvert had been installed to reduce the outflow into the lower part of Taylor Gully. That backed water up.
  • A second reinforced concrete box culvert had not yet been installed farther up the ditch that might have held back some of the water that flowed into Elm Grove.

Critical Corner of Chaos

Jeff Miller, an Elm Grove resident who came within inches of flooding dubbed this corner of the development the “Critical Corner of Chaos.”

Jeff Miller schematic showing series of problems near area that flooded. To his list, I would add the culvert across the ditch by the road that did not yet exist.

Photographs of debris patterns left in grass near the diagonal part of Taylor Gully show that water started overflowing the banks as far west as the road that crosses the ditch. From there, it headed straight south toward Elm Grove.

Debris from flood caught in grass high above ditch indicates that water went out of banks near the proposed street that connects the north and south sections of Woodridge. From here, the water headed overland toward Elm Grove in the background.

Also, when water started to make that 120 degree turn at the top of Miller’s diagram, it overflowed the banks into North Kingwood Forest. Part of the water also split off on the other side of the ditch and headed toward Elm Grove. The constrictions caused by:

  • Flowing from a large ditch into a smaller ditch
  • Flowing from the small ditch into a 3-foot pipe
  • Not enough detention excavated
  • Restricted outflow at the box culvert

…all forced water to flow into surrounding neighborhoods and down streets. Overland sheet flow added to street flooding already present raised the level of the water enough to enter at least 196 homes. The main paths that the water took looked something like this.

The red line shows the location of the buried 3′ pipe. Blue lines indicate the MAIN flow of water. Note, it also spilled out onto other side streets. This map shows the main flow, not the extent of flooding.

Current and Future Concerns

It’s been three weeks since the flooding. As the site continues to take shape, and as we officially enter hurricane season this week, several things should concern residents.

  • Rebel Contractors is far from having all the detention ponds excavated.
  • The dirt they have excavated is being used to elevate Woodridge above Elm Grove.
  • The drainage scheme LJA envisioned at the southeastern corner of the subdivision may not be sufficient in future heavy rains to prevent flooding in neighboring communities.
  • Taylor Gulley in Kingwood may not have sufficient conveyance to handle the volume of water coming from upstream development.

I mention this last point because older subdivisions in Porter along the western edge of Woodridge also flooded. Apparently, Woodridge blocked, at least partially drainage flowing from those areas. Therefore, less water came from that area than normal. Had it been added to the May 7th flood, things in Elm Grove and North Kingwood Forest could have been even worse.

Dirt excavated from S2 Detention Pond is being used to raise elevation of land elsewhere in development. Homes along Needham Road in Porter are in background by cell tower.
Jeff Miller, who helped with this analysis, stands on the original level of the land next to a street that will be about three feet above the elevation of Elm Grove. Miller stands 6′ tall. Note the fire plug at his eye level.

Urgent Recommendations

Before all of Woodridge Village becomes set in concrete, we need the best engineers in town to re-evaluate the LJA plans independently, especially at the “critical corner of chaos.” Then I hope the developer hires additional resources to ensure a verified or improved plan is executed before we hit the peak of hurricane season in August and September.

All thoughts in this post represent my opinions on matters of public policy and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP statute of the great State of Texas.

Posted by Bob Rehak on 5/28/2019 with help from Jeff Miller

637 Days since Hurricane Harvey