Tag Archive for: What went wrong

What Went Wrong, Part V: How Woodridge Village “Soiled” Perry Homes’ Reputation

Before Perry Homes bought the ill-fated land now known as Woodridge Village, it hired a company called Terracon to sample soils and submit a geotechnical analysis. Their objective: to see whether the land was suitable for residential development. Perry also hired LJA Engineering to analyze drainage. However, it appears that LJA did not consider Terracon’s findings when it modeled runoff (see Section 1.4 of LJA’s report).

LJA also assumed that “sandy loam” covered the entire site when the National Resources Conservation Service soil database shows sandy loam covers only 60 percent. The Terracon report, however, never even mentions “sandy loam.”

Different Findings Could Have Skewed Runoff Analysis

Both the different characterizations of soils and their extent could have skewed the results of LJA’s runoff analysis.

LJA said the soil was “fine sandy loam,” everywhere, period. Terracon bored holes to 20 feet at four locations and found mostly clay-based soils. Terracon did, however, find “sandy silt” with “clay pockets” in the first foot of ONE of their borings.

According to the USDA’s Natural Resources Conservation Service (NRCS), clay, sand and loam absorb rainfall at vastly different rates that can approach or even exceed 10X.

Source: Natural Resources Conservation Service, USDA

The NRCS site above does show “sandy loam” on 60% of Perry Homes’ property. However, the NRCS sampling technique usually involves a shovel. They appear to classify primarily surface soils (not surprising for the Department of AGRICULTURE).

That’s why NRCS clearly states that the infiltration rates above only apply to the first two inches of rain during an event. After that, the water may percolate down to another, less permeable layer of soil, such as the clay that Terracon found. At that point, fully saturated ground could force additional rainfall hitting the surface to pond or, if the land slopes, run off. That’s exactly what happened on May 7th and September 19th this year when Elm Grove flooded from Woodridge Village runoff.

According to NRCS, “Soil survey interpretations are rarely suitable for such onsite evaluations as homesites without further evaluations at the specific site.” 

But Terracon’s preliminary investigation sampled only four widely spaced spots at the perimeter of the property. None coincided with the locations of planned detention ponds, known wetlands, or streets. Only one even came close to a future home site. And the Montgomery County Engineer’s office has no record of Terracon performing additional work on the Woodridge site.

Also note that while NRCS shows sandy loam on 60% of the site, LJA assumes uniform distribution everywhere. That could also have skewed LJA’s computer modeling. NRCS showed that another 33% of the site (see below) contained soil consistent with wetlands. Wetlands don’t typically absorb water, often because of clay underlying them.

Wetland-Type Soils on ONE THIRD of Property “Overlooked”

A top geologist retired from one of the world’s largest oil companies sampled the soil at one of Terracon’s borehole sites shortly after the May 7th storm and confirmed Terracon’s findings as to surface soil type – mostly clay.

He also says, “The presence of clay close to the surface can cause water to pond and lead to the formation of wetlands wherever you find depressions in the land.” And in fact, the USGS National Wetlands Inventory shows extensive wetlands on the northern portion of the site.

USGS National Wetlands Inventory map of Perry Home’s site.

It’s not clear where LJA found its soil information; they don’t specify. But if it was from NRCS, they should have been alarmed by the presence of hydric topsoils on ONE THIRD of the property. Hydric soils are one of the defining ingredients of wetlands. Compare with map below, taken from the NRCS site. SosA and SouA are soil types typical of wetlands.

SosA, Sorter-Tarkington complex, 0 1 percent slopes {Hydric, with inclusions that are non-hydric} and SouA, Sorter-Urban land complex, 0 to 1 percent slopes {Hydric, with inclusions that are non-hydric} comprise approximately 29% and 3.6% of the site respectively.

Building homes over wetlands is dangerous because shifting soil can crack foundations. Wetlands also typically serve as collection points for water.

But LJA never mentions wetlands and the Terracon borehole sampling sites came nowhere near the wetlands on the property. Terracon spaced them widely around the perimeter as you can see from the site map with the red lines above.

Groundwater Levels Not Mentioned In LJA Drainage Analysis

LJA, had it read the Terracon report, might have also been concerned by the discovery of ground water at 15 feet, more than a half mile from Taylor Gully. At Taylor Gulley, contractors hit ground water at about 10 feet when excavating the S2 detention pond. But the pond was supposed to hold 15 feet of runoff. That means ground water reduced its capacity by a third. Even worse, a pond by N3 has had standing water near the ground SURFACE for months!

Note the man-made rectangular pond in the upper right. It has been that full since it first appeared in Google Earth satellite images almost a year ago. That’s not a good sign for another area designated to hold a major detention pond (N3).

That means these ponds will never be able to achieve their promised detention capacities with their current dimensions. There just isn’t enough depth. Engineers measure detention capacity from the top of any standing water, not the bottom of the pond.

More Curiosities Re: Testing and Reports

How strange that LJA’s drainage analysis never once mentions the words “water table” or “groundwater”! Especially when detention ponds are a central feature of the report and mentioned 42 times. LJA never mentions “retention” ponds once, although J. Carey Gray, the high-powered litigator representing Perry Homes, called the ponds that in his letter to the City. For the record, detention ponds have no permanent standing water; retention ponds do.

The first thing you notice about the Terracon report: the title says PRELIMINARY. Terracon also put “preliminary” at the top of every page. And repeated it 35 times within the report. Sometimes as many as three times in a single paragraph. Terracon also specifically recommended several followup tests. But if they were done, the Montgomery County Engineers office says it has no record of them.

Five Previous Developers Sold Site Rather than Develop It

At Thanksgiving Dinner yesterday, we had three engineers at the table. I posed the question, “Do you ever reach a point in projects when you say to yourself, “We shouldn’t do this,” as opposed to “How can we do this?”

The general consensus: There’s always a way to engineer a solution…if you don’t consider cost.

I wonder if that’s why five previous developers who owned this site didn’t do anything with it. They included Lennar, Kingwood 575, Reddy Partnership/Kingwood, Woodbridge 268, and Concourse Development.

It could be that they were just holding it and hoping to flip it at a higher price. Land generally appreciates faster than the rate of inflation. But it could also be that they investigated the cost of developing it more closely than Perry Homes did.

Below: the sales histories for the two major pieces of land that comprise Woodridge Village.

Source: Montgomery County Appraisal District
Source: Montgomery County Appraisal District

Of all the curiosities associated with this development, the sales history ranks near the top. Concourse held the property for less than a week before selling it to Perry Homes’ subsidiary, Figure Four Development LTD.

Perry Homes even commissioned and received Terracon’s Geotechnical report BEFORE Concourse bought the property. But that’s the subject for another post at another time. What was that about?

The important thing to note for now: When you’re selling dirt, it pays to know what kind of dirt you’re selling.

As Perry Homes Drags Out Court Case, It Could Incur More Liability

The once-proud Perry Homes is now buried under a mountain of law suits alleging that their actions flooded hundreds of homes…not once, but twice…in six months.

As Perry Homes drags these lawsuits out, Kathy Perry Britton could expose her father’s company to enough liability to bring it down. Can you imagine how a jury would react if Elm Grove flooded a third time when so many regulations have been flaunted? And when Perry has made no further attempt at mitigation since early August? I can.

Posted by Bob Rehak on 11/29/2019 with help from Jeff Miller

842 Days after Hurricane Harvey and 71 after 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.

What Went Wrong, Part IV: Perry Homes Develops Flood Plain That Wasn’t

Chapter 9 of the Montgomery County Drainage Criteria Manual discusses development in flood plains. Perry Homes and LJA Engineering somehow “overlooked” many of the points in this chapter. A flood plain ran through the property, but FEMA had not yet mapped it. LJA used that as an excuse to claim none existed.

Notice how flood plain mapping stops at county line. Perry Homes has the undeveloped property along and above the county line. Color code: Cross-hatched = floodway; aqua = hundred year flood plain; brown = 500-year flood plain. Source: MoCo Maps

Unfortunately, physical boundaries of flood plains do not observe political boundaries. Taylor Gully bisects this property, if you look at the flood maps, it magically defies flooding on the MoCo side of the county line.

Montgomery County Regulations Affecting Flood Plains

Below are guidelines from the Montgomery County Drainage Criteria Manual that Perry Homes would have had to follow had the property been mapped.

From Section 9.1.1 Floodplain Regulations:

“No fill or encroachment is permitted within the 100-year floodway which will impair its ability to discharge the 100-year peak flow rate except where the effect on flood heights has been fully offset by stream improvements.” [Emphasis added.]

“Placement of fill material within the floodplain requires a permit from the County Drainage Administrator. Appropriate fill compaction data and hydrologic and hydraulic data are required before a permit will be issued.”

From Section 9.1.2 Floodplain Development Guidelines and Procedures

“Construction within the floodway is limited to structures which will not obstruct the 100-year flood flow unless fully offsetting conveyance capacity is provided.”

  • “The existing designated 100-year floodplain and floodway should be plotted on a map of the proposed development.”
  • “The effect of the proposed development and the encroachment into the flood plain area should be incorporated into the hydraulic model and the resulting flood plain determined.”
  • “Careful consideration should be given to providing an accurate modeling of effective flow areas taking into account the expansion and contraction of the flow.”
  • “Once it has been determined that the proposed improvements adequately offset the encroachment, a revised floodway for the stream must be computed and delineated.”
From Section 9.2 Downstream Impact Analysis

“Pursuant to the official policy for Montgomery County, development will not be allowed in a manner which will increase the frequency or severity of flooding in areas that are currently subject to flooding or which will cause areas to flood which were not previously subject to flooding.”

What LJA Said About Perry Homes’ Project

On Page 1-2 of its Drainage Analysis, LJA Engineering explicitly states, “As shown on Exhibit 3, the proposed development is outside the 100-year floodplain.”

Phyllis Mbewe, P.e., CFM, LJA Project Manager – Hydrology and Hydraulics
LJA Exhibit 3 shows the floodplain stopping at the county line. LJA also did its best to make the .2 percent risk area blend into the area of minimal flood risk. This visually minimizes the amount of floodplain bordering MoCo, so the abrupt stoppage at the county line becomes less visible. Source: LJA.

Ms. Mbewe then states in her conclusion, “Based on these findings, the proposed development of the 268-acre tract creates no adverse drainage impacts for events up to and including the 100-year event.” [Emphasis added.]

What Does “No Adverse Impact” Really Mean?

People often twist the definition of terms you think are self evident. Especially in legal, technical, and political contexts.

To me, “No Adverse Impact” should mean, “Downstream people who didn’t flood before won’t flood after development.” That’s what section 9.2 states explicitly.

But when I talked to a flood professional, I got a different answer. To that person, “no adverse impact” meant, “the amount of water flowing across the property did not increase after development.” Much narrower! And seemingly contradictory to the spirit of 9.2.

“Floodplain” Definition Shocked Me

But that person’s definition of floodplain really shocked me. To me, floodplain means “the area adjacent to a stream that fills with floodwater after a very heavy rain.” But the professional told me I was WRONG. To the professional, a floodplain was “an area on a map that FEMA designated a floodplain for insurance purposes.”

In that person’s mind, because FEMA had never mapped the area in question, a floodplain did NOT EXIST. Whether or not the area flooded!

To me, that’s like saying an apple is something you see in a Kroger’s flyer, not something you eat. We’re talking about the difference between a symbol of something and the reality of it.

This discussion proved once again that words and phrases have different meanings that depend on the social context of usage.

In the minimum compliance environment of Montgomery County, LJA and Perry Homes argued that there was no floodplain. They found someone in the county engineer’s office who agreed with them…or was told to agree with them.

FYI, the official FEMA definition says, “Any land area susceptible to being inundated by floodwaters from any source.”

Consequences of Overly Narrow Definition

So did Elm Grove flood because Perry Homes, LJA and Montgomery County did not enforce the floodplain regs in section 9.2 of the Drainage Criteria Manual?

  • They certainly did not offset peak flows with stream improvements.
  • They did not plot the REAL-WORLD floodway and floodplain on a map of the proposed development (see above).
  • LJA did not incorporate encroachment into the floodplain in its hydraulic modeling, because they denied a floodplain existed.
  • Neither did LJA provide “an accurate modeling of effective flow areas taking into account the expansion and contraction of the flow.”
  • Finally, LJA did not compute, revise and delineate the floodway for the stream.

Had they done all these things, perhaps people would have seen that downstream homes that had never flooded were now subject to greater flood risk. But that’s really something for the jury to decide. And it would require FEMA to model the floodplain after the fact.

But like the narrow definition of floodplain, this whole discussion symbolizes a bigger problem.

How Do You Fix a Permissive, Minimum-Compliance Environment?

LJA had an obligation to its client and a higher one to the public that it ignored in my opinion.

Perry Homes could have demanded honest answers from its engineers, not the ones they wanted to hear.

FEMA could label areas like Woodridge Village “UNMAPPED”. This would send a signal to potential home buyers if sellers tell them they’re NOT in a floodplain. That might make developers think twice.

Home buyers need to demand integrity in this process. They need to ask better questions. They need to learn more about flooding.

But at the end of the day, Montgomery County Commissioners must define the kind of future they want. Do they want constant flooding? Or not. Because right now, they’re competing with other areas for new development on the basis of willful blindness and self-serving definitions.

Thirty years down the road, when it’s too late to fix the infrastructure problems they ignore today, MOCO residents will be paying the price. Some, who have flooded repeatedly, might argue they already are.

Posted by Bob Rehak on 8/26/2019 with help from Jeff Miller

820 Days after Harvey and 69 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.

What Went Wrong, Part III: Perry Homes’ Woodridge Village Detention Pond Catastrophe

Note: This is the third in a five part series about What Went Wrong in Woodridge Village that may have contributed to flooding in Elm Grove and North Kingwood Forest. It focuses on Detention Ponds.

Section 7 of the Montgomery County Drainage Criteria Manual cautions, “The introduction of impervious cover and improved runoff conveyance serves in many cases to increase flood peaks quite dramatically over those for existing conditions.” And that’s exactly what happened in Elm Grove and North Kingwood Forest in May and September of this year. Two subdivisions that had never flooded before were inundated with several feet of water from Woodridge Village.

Perry Homes failed to observe numerous regulations in the Drainage Criteria Manual including provisions for:

  • Erosion control measures such as pond linings, revegetation, backslope swales
  • Maintenance roads
  • Increases in downstream flooding
  • Geotechnical reports for detention ponds
  • Drainage of detention ponds

Critically, they also failed to construct all the detention ponds they promised.

Less than a Quarter of Detention Ponds Built

When listing factors that contributed to the flooding, the absence of several promised detention ponds should rank near the top.

  • Before the May flood, only one of five detention ponds (S1) was substantially complete and it provided only 7% of the promised detention capacity.
  • Before the September flood, contractors substantially completed a second detention pond (S2) that added another 16% of promised detention capacity.
  • Since then, no work has been done on additional excavation to protect against flooding.
While clearcutting ALL of the land, Perry Homes installed only PART of the detention.

According to LJA Engineering, Perry Homes was supposed to develop the project in two phases and clearcut only 30 acres in the northern section during Phase 1. However, something changed. Instead, Perry Homes clearcut the entire northern section. And they still haven’t excavated any of the three detention ponds there.

By May 2019, only S1 was substantially complete. By September, S2 was also substantially complete, but overwhelmed.

Had Perry Homes installed all the detention that it promised, the site should have detained a foot of rainfall. But it didn’t. When Imelda came along, it was like trying to pour 100 gallons of water into a 23 gallon jug. Water spilled out of the development into adjacent streets and homes.

Erosion Control Measures Missing for Detention Ponds

Section 7.2.7 of the Montgomery County Drainage Criteria Manual details Erosion Control Measures for Detention Facilities. It states:

“The erosion potential for a detention basin is similar to that of an open channel. For this reason the same types of erosion protection are necessary, including the use of backslope swales and drainage systems (as outlined In SECTION 6), proper revegetation and pond surface lining where necessary. Proper protection must especially be provided at pipe outfalls into the facility, pond outlet structures and overflow spillways where excessive turbulence and velocities will cause erosion.” (See page page 123 of pdf, numbered 113 in doc.)

Not much grass in S1 (right of the road) or the area that drains into it. All aerial photos below taken on 11/4/2019.
Not much grass on the slopes of S2 either, although Perry Homes did make an ineffective attempt to hydromulch the south (right) border.
No Protection for Overflow Spillway
Perry Homes quality! This spillway from Taylor Gully (right) was supposed to have a grass lining, but still does not. Picture taken 11/4/2019. As of 11/21/19 work still had not started on the lining. Perry Homes has done virtually no work on this pond for three months. However, they did start lining the channel on the right today.
Backslope Interceptor Swales?
The northern edge of the S2 pond has no backslope interceptor swale. As a consequence, water from Taylor Gully at the top of this frame flows over the edge of the pond and erodes it. This may not be a sustainable solution. In the long run, the Gully could erode its way into the pond from the north (top of the frame).

Maintenance Road Missing at Critical Point

Section 7.2.8 talks about Maintenance of Detention Facilities. It states, “A 30-foot wide access and maintenance easement shall be provided around the entire detention pond.” The most critical place in the entire chain of detention ponds, the final outflow culvert into Taylor Gully, has no room for a maintenance road. That’s because when they installed the required backslope interceptor swale, the only place left for it was the maintenance road. That’s planning for you!

S2 has no maintenance easement or road at final outfall into Taylor Gully. The backslope interceptor swale takes up that space.

No Increase in Downstream Flood Levels Allowed

Section 7.3 talks about DETENTION DESIGN PROCEDURES. It clearly lays out the design goal when it says…

No increase in downstream flow rates or flood levels will be allowed.

Further down in this section, the regulations state: “The maximum 100-year water surface elevation in all detention facilities shall be a minimum of 1 foot below the minimum top of bank elevation of the basin.”

Judging from this video shot by Edy and Ricki Cogdill during the May 7th storm, I would say Perry Homes didn’t meet that objective. It reminds me of that slime show on Nickelodeon, but in this case, the innocent bystanders got slimed.

No Geotechnical Report for Groundwater Level at Pond Sites

Section 7.5 discusses GEOTECHNICAL INVESTIGATIONS. It says, “Before initiating final design of a detention pond, a detailed soils investigation by a geotechnical engineer should be undertaken.” Regulations state that the ground water investigation must be “at the proposed site.” Montgomery County has no record of such an investigation or report.

A company called Terracon prepared a Preliminary Geotechnical Report for Perry that addressed issues pertaining to utilities, road pavement and residential foundations. But it makes no mention of detention ponds.

The company took four widely spaced borings around the perimeter of the site that managed to miss all the detention pond locations. Significantly, they missed all the wetlands, too.

Page 17 of Terracon Report. Red lines added to improve visibility of locations.

MoCo Claims It Has No Further Geotechnical Reports

If Perry Homes did additional investigations into ground water on this site, Montgomery County says it doesn’t have them.

If no further investigations were conducted, this could be a fatal flaw affecting the economics of the entire development. Note the presence of standing water in the photo below.

S2 Pond (left), Taylor Gully (center), and area where N3 pond will go (right) all have standing water that will reduce their rated capacity.

The presence of standing water reduces the rated capacity of detention ponds and channels. Only the area above the standing water counts as capacity. Regulations say that these ponds should drain completely (see below).

Thus, S2 likely has lost a third of its designed capacity. N3, when eventually built, could fare worse. Note how close the water is to the surface in the small pond on the right.

If you can’t go deep to get your detention pond capacity, you have to go wide. And that will mean fewer homesites than the 896 they planned. This site might not even make economic sense for building homes.

Problems with Homes Built Over Wetlands

The presence of wetlands in the northern section, which the Terracon report never mentions, would also significantly reduce the site’s suitability for building homes.

This article describes the problems with homes built on wetlands. The title: “Caution: Building in a Wetland Can Be Hazardous to Your House.” A biologist for the US Fish and Wildlife service who investigated filled wetlands in Pennsylvania warned: “Build your house in a wetland, and you’ve got a hobby for the rest of your life. You will be fighting that water forever.” He discusses cracked foundations and also warns, “When wetlands are filled, the water that made them wet has to go somewhere. … the water likely is leaking into formerly dry homes of downstream property owners.”

I’m sure Perry Homes would divulge the presence of former wetlands to the future buyers of homes on this site. It’s the only ethical thing to do and Kathy Perry Britton, CEO, has standards to maintain.

Incomplete Drainage of Detention Ponds

Section 7.6 of the Drainage Criteria Manual addresses GENERAL REQUIREMENTS FOR DETENTION POND CONSTRUCTION. It states:
“A pilot channel shall be provided in detention facilities to insure that proper and complete drainage of the storage facility will occur.” (Emphasis added.)

Complete drainage will likely never occur in S2 and N3 because of the high water table.

To excavate S2 to the required design depth, contractors had to continuously pump water out of it as they worked. It still retains water to this day.

Photo by Jeff Miller on June 2, three days after contractors started digging to the final depth. No surface linings were ever added to this portion of the pond per Section 7.2.7 of the MoCo Drainage Criteria Manual.
Photo taken on June 3 shows contractors were pumping water out of pond as they continued excavating.

If Perry Homes continues its Woodridge Village venture using its current plans, chances are, the company will never provide enough detention capacity for real world conditions. When modeling, their engineers did NOT use the current Atlas-14 rainfall statistics from NOAA.

The new statistics would require 40% more capacity to ensure downstream safety.

Where Does Perry Homes Go from here?

After ignoring regulations, hundreds of homes flooded. And they will flood again. Owning this site is like hanging a millstone around one’s neck. It could drown the entire company in perpetual litigation and debt.

Future Posts in this series will look at:

  • Contradictions in Perry Homes’ Plans
  • The Dirt on Perry Homes’ Soil Test
  • The Floodplain that Wasn’t

Posted by Bob Rehak on 11/21/2019 with help from Jeff Miller

814 Days since Hurricane Harvey and 63 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.