Harris County Flood Control District (HCFCD) has a large active construction project underway in Tomball. Phase I of the project stretches about two-thirds of a mile from SH249 to FM2920 on a tributary of Willow Creek as it arcs around a major shopping center near downtown Tomball and Lone Star College/Tomball. The project includes channel widening and deepening; dry and wet stormwater detention basins; and opportunities for recreational trails.
Willow Creek: A Study in Contrasts
The Willow Creek watershed is located in northwest Harris County. It drains about half of the City of Tomball. The tributary highlighted above flows through densely developed shopping and medical center areas on the northern end to agricultural and oil and gas interests on the lower end.
Willow Creek: Present and Future
Willow Creek flows into Spring Creek just upstream of where Spring Creek crosses under I-45. The Willow Creek watershed covers about 54 square miles. The downstream end of the watershed is within the floodplain of Spring Creek.
Willow Creek watershed is mostly undeveloped. Significant development is limited to the City of Tomball and a few residential subdivisions in the lower end. The development rate has not been very rapid. However, officials expect it to increase as the City of Tomball continues to expand and urbanization from Houston stretches northwest.
This project will directly benefit mostly areas on the northwest side of the county. However, it may provide some downstream benefit by holding back water in major floods.
Goal: Contain Runoff from 100-Year Event
Phase 1 of this project began construction activities in January 2021. As funding becomes available, future phases of the M124-00-00 project will continue channel conveyance improvements and construct several more stormwater detention basins from F.M. 2920 to the confluence with Willow Creek. Phase II will also deepen the channel improvements from Phase 1 that you see above.
The overall goal of the M124-00-00 project is to enable the channel to contain the 1-percent (100-year) storm event within the channel banks based on existing watershed conditions.
The total project focuses on conveyance improvements of stormwater in the area, as well as reducing flood risk through construction of stormwater detention basins. Stormwater detention basins reduce flooding risks by taking in and temporarily storing stormwater during heavy rain events and releasing the water back into the waterways when the threat of flooding has passed.
Multiple new detention basins along the M124-00-00 channel will add approximately 390 million gallons of storage capacity (an approximate 2,164 percent increase in current storage capacity) to benefit the Willow Creek watershed. That’s enough to contain a foot of water falling on 1200 acres.
Posted by Bob Rehak on 12/26/2021based on info from HCFCD.org
1579 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/12/20211224-DJI_0258.jpg?fit=1200%2C799&ssl=17991200adminadmin2021-12-26 12:35:472021-12-27 11:40:39Willow Creek Widening and Stormwater Detention Basins Improving Tomball Drainage
Construction has begun on another massive detention pond along Halls Bayou. It stretches south from Isom Street to the bayou between Chrisman and Aldine-Westfield Roads. It covers approximately 26 acres and when complete will hold 180-acre feet of stormwater to reduce the risk of flooding. This is just one of 11 projects comprising the Halls Implementation Program. Together they have a total current value of $212 million dollars.
Such basins take in excess stormwater during heavy rain events and then release it slowly back to the channel when the threat of flooding has passed. Part of the basin will have a wet bottom and another part will have a vegetated shelf. Yet another part will go in between Isom and Aldine Mail Route Road, although that portion has not yet begun construction. (See below).
Harris County Flood Control District (HCFCD) lists the project as C-25 on its website. But the Flood Bond Program ID is P518-11-00. Ultimately, this will become part of a much larger project area that includes P118-21-00. Together, they will improve drainage in a large part of east Aldine.
Each of these projects falls into Commissioner Adrian Garcia’s Precinct 2. The description that accompanies the project in the flood-bond spreadsheet says, “This project could reduce the risk of flooding for over 90 buildings and could reduce the 1% floodplain for over 100 acres.” The HCFCD spreadsheet and website indicate a total cost of more than $14 million.
But keep this in mind. Project C-25 will work in conjunction with two proposed Harris County Engineering Department projects: neighborhood drainage improvements in the Western Homes subdivision and proposed roadway and drainage improvements along Aldine Mail Route Road. The detention capacity in the pond you see here will accommodate drainage improvements in those areas without flooding other areas. Thus, the pond will really help more than 90 structures.
C-25 is a partnership project. HCFCD received an approximately $9.5 million Community Development Block Grant for Disaster Recovery (CDBG-DR) from the US Department of Housing and Urban Development (HUD). Approximately $5.4 million comes from local funding.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/10/20211013-DJI_0559.jpg?fit=1200%2C799&ssl=17991200adminadmin2021-10-13 13:52:592021-10-13 20:28:46Another Massive Detention Pond Going In Next to Halls Bayou
Between US59 and Sorters-McClellan Road, a few blocks south of Kingwood Drive, New Caney ISD High School #3 is finally taking shape. And it now has an official name: West Fork High High School.
On January 1, 2021, contractors were just starting to pour concrete for the foundations and parking lots. According to the New Caney ISD’s June update:
Site work storm drainage is 95 percent complete
Sanitary sewer system – 85 percent.
Electrical system – 98 percent.
Water system – 90 percent.
Building concrete slab – 90 percent.
Form and pour tilt-up panels – 99 percent.
Erect panels – 95 percent.
Structural steel – 55 percent.
Metal decking – 20 percent.
Concrete masonry unit (cinder block) masonry – 10 percent.
Aerial Photos Taken 7.12.21
Here’s how all that looked on the afternoon of July 12, 2021.
Site Plan, Architectural Renderings for New Caney ISD West Fork High School
Here’s how it should all look when finished.
New Caney ISD expects to finish construction on the 60-acre site in the summer of 2022. The site is in Montgomery County, but also the City of Houston’s Extra-Territorial Jurisdiction.
Detention Pond Requirements
The dry-bottom detention pond takes up approximately 5 of the 60 acres – or one twelfth of the site. Assuming it’s 12 feet deep, it would hold a foot of rain falling on the entire site. The new minimum recommendation for a site this size in Harris County and the City is .65 acre feet of detention per acre. That would be about 40 acre-feet of detention, which a pond 8 feet deep would hold.
Because the construction site is closed, and the plans I have don’t specify depth, it’s hard to say exactly how much capacity the detention pond has. But I’m guessing it’s deep enough to meet the new minimum requirements under Atlas 14. I say that judging by the height of the pond walls compared to the pipes leading into it.
I would expect no less from a public school system.
Posted by Bob Rehak on 7/12/2021
1413 Days after Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2021/07/20210712-DJI_0066.jpg?fit=1200%2C799&ssl=17991200adminadmin2021-07-12 17:54:312021-07-12 17:55:11New Caney ISD’s New West Fork High School Taking Shape
Perry Homes’ current contractors have excavated 3X more detention pond volume in ten weeks than the previous contractors did in virtually two years. During this past week, they finished excavating three ponds on the northern section of Woodridge Village. Together, they comprise 77% of the total detention volume for the whole site.
Excavation Done, but Finish Work Remains
That doesn’t mean they’re totally done with the ponds. Recent aerial photos show that they still have much finish work to do. That includes:
Shaping the sides
Creating backslope swales
Installing pipes to funnel water from the swales into the ponds and channels
Ensuring water can flow out of Adams Oaks in Porter on the west side of the subdivision into Taylor Gully as it previously did
Creating concrete “pilot channels” in the center of the ponds and larger channels
Planting grass along the sides of the slopes to reduce erosion
Installing outflow control in several places to hold back floodwaters
Building maintenance roads around the ponds
Elm Grove resident Jeff Miller, who monitors the progress of construction daily, says crews are already hard at work on many of those tasks.
With the peak of hurricane season now less than two months away, Perry Homes is in a race against risk. The company may regret the six months of virtual inactivity between the completion of pond S2 and the start of work on ponds N1, N2, and N3 in early April.
The faster pace of current construction puts pressure on Harris County and the City of Houston to complete an offer if an offer will be made. Elm Grove residents lobbied the City and County to purchase the property and build a regional flood detention facility. They center would also help protect downstream residents on the East Fork and Lake Houston.
Since then, the County has clamped down on communications regarding this subject. Rumors suggest that all parties are still trying to make a deal happen. But the County has denied all FOIA requests and referred them to the Texas Attorney General for a ruling on their denials. That often happens when negotiations are in progress, according to a knowledgeable source.
What Happens Next?
At the contractor’s current rate of progress, it’s entirely possible that contractors will complete all work on detention ponds in July.
With approximately $14 million dollars invested in the property, with hurricane season here, with lawsuits pending, and knowing that the amount of detention is insufficient to hold a 100-year rain, Kathy Perry must be sweating bombshells.
Ms. Perry may be hoping for a City/County offer, but she can’t be counting on one. If she were, she could have sold the dirt coming out of those detention ponds. Instead, however, she’s building up land elsewhere on the site to keep her options open and develop the site if a deal falls through.
That dirt will have to be moved again at taxpayer expense if the county builds additional detention ponds.
Pictures of Site as of 6/19/2020
Here’s what the site looked like as of 6/19/2020.
Need for Grass if Deal Not Reached Quickly
Note how the grass on the southern side of the gully has all died. That raises a question. If Perry, the City and County do not complete a purchase agreement soon, will Perry plant grass on the northern section to slow runoff. Right now, it’s all hard-packed dirt.
Planting grass over an area this large would be a big investment and might get in the way of construction if Perry decides to develop the land. But it will reduce flood and legal risks.
Posted by Bob Rehak on 6/20/2020
726 Days after Hurricane Harvey and 275 after Imelda
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/06/20200619-DJI_0205.jpg?fit=1200%2C900&ssl=19001200adminadmin2020-06-20 14:57:582020-06-20 14:58:16Perry Contractors Now Focusing on Finish Work for Detention Ponds
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
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 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.
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.
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
“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.)
No Protection for Overflow Spillway
Backslope Interceptor Swales?
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!
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.”
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.
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.
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.
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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/11/RJR_4350-2.jpg?fit=1500%2C1089&ssl=110891500adminadmin2019-11-21 17:48:092019-11-21 18:26:13What Went Wrong, Part III: Perry Homes’ Woodridge Village Detention Pond Catastrophe
NOAA redefined the amount of rainfall it takes to qualify as a 100-year or 1000-year event. They defined the new 100-year rain as 17.3 inches in 24-hours – a 42% increase. That means that to meet new 100-year standards, Perry would have had to increase its detention capacity by 42%. Instead of 271 acre feet, it would have needed 385.
Using Atlas 14 would have reduced the number of salable lots and the economic projections for the development to a substantial degree.
Woodridge Plans Approved Even Before LJA Submitted Hydrology Report
Now here’s where it gets even more interesting. City of Houston approved the detention plans on 8/12/18 – two weeks BEFORE the LJA hydrology report on 8/28/18 and only a month BEFORE NOAA released the new Atlas 14 data. Hmmmm! Think they were in a hurry to get these approved? (Note: The approval date for MoCo is unreadable).
Perry Homes played a game of beat the clock and was winning … until May 7, 2019.
Future Flood Risk Remains Even with Planned Detention Ponds
Until now, I have been posting about the lack of detention ponds. Closer analysis reveals that this is only part of the problem. Even if Perry builds the remainder of the detention ponds as planned, they will be insufficient to meet the new NOAA standards and will pose a flood risk to people downstream.
After contributing to two floods in Elm Grove and North Kingwood Forest, the engineers and owners of Woodridge Village surely must realize how dangerous trying to Beat the Clock was.
Forty-two percent of a 100-year flood as defined by the new Atlas-14 data will overflow the banks of the detention ponds and add to the load on Taylor Gully or go into the streets of Elm Grove and North Kingwood Forest.
This image taken Friday night at Sunset shows how impervious the Woodridge soil is. Water is still ponding three and a half days after a two-inch rain (October 28, 2019).
795 Days after Hurricane Harvey and 45 after Imelda
The thoughts expressed 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/11/Aerial-Perry-Sml.jpg?fit=3553%2C851&ssl=18513553adminadmin2019-11-01 23:33:312019-11-03 20:13:20Woodridge Village Detention Calculations Off by More Than 40% According to New Standard
A week after J. Carey Gray, a lawyer representing Perry Homes’ subsidiaries and contractors, promised the Mayor of Houston that his clients would move as quickly as possible to complete Woodridge detention ponds, there still has been no excavation activity at the job site. And in fact, according to Jeff Miller, an Elm Grove resident who visited the site today, much of the material and equipment that had been on site are now gone.
Lack of Detention Implicated in Two Floods
Twice in four months, Elm Grove and North Kingwood Forest flooded severely when water from Perry Homes’ troubled Woodridge Village development overflowed into the streets of those communities immediately south and east of Woodridge.
Before the May flood, Perry had clearcut virtually the entire 268 acres, but installed only 7% of the detention.
Before the September flood, they had substantially completed only one more pond, bringing the total to 23% of the planned detention.
So it’s not too surprising that the completed detention ponds overflowed in heavy rains.
It was like trying to store 100 gallons of water in a 23 gallon container.
Excavation Work on Detention Ponds Stopped for Two Months
As the pictures below show, there’s one piece of excavation equipment on the northern portion of the site and it hasn’t moved for about a month.
Eight days later, you can see the same equipment still in the same place. However, it appears that two other pieces are now parked with it.
Only Modest Repair Work on Ponds Since August
Resident Jeff Miller reported that an excavator removed some eroded sediment out of one completed pond (S1) after Imelda. Below is the photo he took on 10/6/2019. However, this was repair work, not newexcavation work.
However, no new detention capacity exists on the northern section which has the steepest slope and the largest surface area. It was to provide 77% of the total detention.
N-1 and N-2 should provide 62% of the detention capacity. However, N-1 doesn’t exist. N-2 is not fully excavated. And N-3, which will provide another 15% is only a distant dream.
Hundreds of Families Remain at Risk
The lack of progress on detention places hundreds of families at risk as we slog our way through another 5 weeks of hurricane season. The season ends on November 30. But flood-weary residents also remain wary of non-tropical storms, such as Tax Day, Memorial Day, and May 7th this year. In the moist, Gulf-coast region, heavy storms can strike any time of year.
Now, there’s an iron-clad contract if I ever saw one! However, as of October 22, 2019, no residents that I consulted around the site had seen any workers recently. Mr. J. Carey Gray, Attorney at Law, dated his letter October 17th.
According to resident Nancy Vera who lives immediately south of the construction site, there has been no recent construction activity anywhere on the site that she or her family can see.
Gretchen Smith who can see the site from her front yard in Porter has seen no workers.
Jeff Miller visits the site almost daily to check progress or non-progress of work. He had not seen any workers lately either. Moreover, he said that much of the materials and heavy equipment that had been stored on site appear to be gone.
Maybe Mr. Gray needs to consult with Larry, the Cable Guy.
Posted by Bob Rehak on 10/23/2019, with help from Jeff Miller, Nancy Vera, and Gretchen Dunlap-Smith
785 Days since Hurricane Harvey and 34 since Imelda
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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/10/Excavator-Highlighted.jpg?fit=1500%2C1000&ssl=110001500adminadmin2019-10-23 00:11:302019-10-23 00:12:40One Week After Town Hall, Still No New Work on Woodridge Village Detention Ponds
Many homes flooded in Elm Grove this week that did not flood on May 7th, or ever before. Estimates from the homeowner’s association range from 2 to 3 times the number that flooded on May 7th. The shocking part: most of the flooding was preventable.
History of Problems with Woodridge Village
On May 7th, floodwater from a new development in Montgomery County contributed to the flooding of almost 200 homes in Elm Grove Village.
The basic problem: Perry Homes, its subsidiaries and contractors had clearcut approximately 268 acres. They filled in natural streams and wetlands without installing needed detention ponds. Runoff from the development then went straight into Elm Grove.
In the weeks that followed, hundreds of Elm Grove residents filed lawsuits against the developer and contractors. In the months that followed:
The Perry gang, managed to complete less than 25% of the needed detention pond capacity, despite ideal construction weather, and then they apparently stopped work altogether.
Drone Footage Shows Huge Clearcut Area Where Three Detention Ponds Should Have Been
As work came to a standstill, residents became concerned. Last Sunday, Matt Swint flew his drone over the development to document the status of work on detention ponds. Just four days later, Imelda struck.
Swint captured all three of the images immediately below on 9/15/2019. They show that no progress was made on ANY of the detention ponds planned for the northern section.
No Work Ever Done on Northern Detention Ponds Despite Area Having Been Clearcut for Months
They could have hired extra crews to build those northern detention ponds. But no. Why be aggressive when you’re months behind schedule and have ideal construction weather?
Their lawyers were, however, working overtime, blocking discovery in the court case against the developer and contractors.
A judge failed to recognize the dire threat that Elm Grove residents still lived under. She may have unwittingly contributed to this mess. With no sense of urgency, she tolerated deliberate delays and set a trial date a year away.
On September 19, Elm Grove flooded again. Worse than on May 7th. Much worse. Beth Guide of the Elm Grove Homeowners Association and numerous homeowners estimate that the water was at least a foot to eighteen inches deeper. The additional water involved twice as many streets, and affected as many as two to three times more homeowners. Now they, too, get to join the lawsuit and battle institutional indifference. (Note: many streets are so congested that it is virtually impossible to get an exact count at this time. That number could change.)
Scenes from Elm Grove, One Day after Second Flood in Four Months
Witnessed men and women weeping openly as they hauled belongings to the curb for the second time in four months.
Watched kids discarding Christmas and birthday presents in trash piles that sometimes reached rafters.
Talked with a family that had just finished installing replacement cabinets from the May 7th flood.
Saw desperation in the eyes of young couples who feared bankruptcy.
Met the grown children of elderly people there to help salvage what they could for parents.
Defendants’ Responses to Plaintiffs’ Questions
As this tsunami of heartbreak unfolded in front of me, I could not get the defendants’ responses to the plaintiffs’ simple requests out of my mind.
Request: Identify the entity or individual in charge on May 7, 2019.
Response: “Defendant objects to this Request for Production on the grounds it is vague, ambiguous, unclear and overly broad with respect to the requesting party’s use of the phrase ‘in charge…'”
Or how about this one:
Request: Identify the person in charge of permit compliance.
Response: “Defendant objects to this Request for Production on the grounds that such Request is vague, overly broad, and fails to specify and/or describe with reasonable particularity – as is required by Rule 196.1(b) of the Texas Rules of Civil Procedure — the documents and/or things to be produced. Defendant further objects to this Request for Production on the grounds that such Request is argumentative and assumes the truth of matters which are not in evidence, and which may be in dispute, to the extent that such Request suggests and/or assumes that one specific individual was “… in charge of compliance …” by this Defendant as to the terms and conditions of TPDES General Permit TXR150000.”
Whew! That lawyer must be getting paid by the word. I know some people that could have communicated the same meaning with a finger gesture.
The judge in this case will hear a motion to compel responses on Monday, September 23rd in the 234th Judicial District Court of Harris County. I hope she puts a stop to this nonsense. It’s time somebody did…with the rain train spread out across the Atlantic during the worst part of hurricane season.
What 23% Retention Contributed To
This video shows what the people of Elm Grove faced during Imelda from Woodridge Village and what they will continue to face. With only 23% of the detention capacity in place, it overflowed when the design limits were tested. See video below.
It’s kind of like expecting a car with one tire to work as well as a car with four.
One Day After the Latest Storm
Posted by Bob Rehak on 9/20/2019, with images from Matt Swint, Allyssa Harris, Jeff Miller
752 Days after Harvey and One Day after Imelda
All thoughts expressed in this post are my opinions on matters of public opinion and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP statute of the Great State of Texas.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/09/Woodridge-N1-Detention-Pond-Location.jpg?fit=1500%2C994&ssl=19941500adminadmin2019-09-20 23:02:182019-09-21 07:54:07Elm Grove Has 2-3X More Damage Than After May 7th, Much of It Foreseeable and Preventable
A November 2018 article appearing in the peer-reviewed scientific journal Nature found that urban growth can intensify both rainfall and runoff from hurricanes. Further, urban growth can increase the risk of flooding and shift the location of flooding. The article specifically studied the effects of Hurricane Harvey on Houston and found that urban growth increased the probability of such an extreme flood across the basin by 21X.
The Nature study looks at two distinct effects of urbanization. The first is the impact of impervious surface on RUNOFF. The second is the impact of the urban landscape’s surface roughness on RAINFALL.
The Runoff Component
Numerous studies have looked at the relationship between percentage of impervious cover, runoff, and flooding – a well documented phenomenon. Impervious cover accelerates transport of rainfall from neighborhoods to rivers. That raises peak flows rather than spreading them out over time. Dr. William Dupre, professor emeritus from the University of Houston visualized the relationship this way.
Rainfall Component Much Less Studied
However, the effect of urban growth and a city’s surface topography on RAINFALL from hurricanes is much less studied. The authors say in Nature that, “Urbanization led to an amplification of the total rainfall along with a shift in the location of the maximum rainfall.” (Page 386).
“Much less is known regarding the urban effects on the organized tropical rainfall of a hurricane, in particular during one like hurricane Harvey, which stalled for several days.” They continue, “…experiments (with computer models) clearly show a large increase in rainfall arising from urbanization over the eastern part of the Houston area.”
The authors compared present and past urban landscapes and also modeled a scenario in which the entire region was cropland.
Mechanisms Responsible for Increase Rainfall
To understand the physical mechanisms responsible for the heavier rainfall, they analyzed the vertical convergence of winds and wind fields.
“The enhanced rainfall … and the shift of rainfall … are tied to the storm system’s drag induced by large surface roughness,” say the authors.
Scientific American explains in more detail. Kerry Emanuel, an atmospheric scientist at Massachusetts Institute of Technology, who did not work on the study said, “We know cyclones are sensitive to characteristics of the surface—mountains, streams, marshland. This new twist is that cities have become big enough to tangibly alter the storm.” Said Gabriele Villarini, an environmental engineer at The University of Iowa and an author on the study, “We removed the urban areas from Houston and replaced them with cropland.”
“The presence of urban areas enhanced all the things you need to get heavy precipitation,” Villarini, one of the study’s authors says. “A stronger drag on the storm winds, associated with a larger surface roughness length” contributed to the increased rainfall.
Emanuel explained, “First, the artificial ruggedness of an urban area slows air down. Whenever air slows in a hurricane, he says, it gets shunted toward the center of the storm and up into the sky. That increases rainfall everywhere [in a metropolitan area].” He added, “A storm moves particularly slowly over downtown areas where buildings are tallest, but the winds bearing down from outside the city are still moving quickly. So, [the storm] is piling up on the city.”
Impact on and Implications for Houston
This increase in urban growth in flat terrain creates problems from a flood perspective, despite mitigation measures already in place.
Urbanization has increased the probability of an event like the flooding associated with Hurricane Harvey by about 21 times, say the authors in Nature on page 388.
The authors make several high-level recommendations.
Urban planning must take into account the compounded nature of the risk now recognized.
Flood mitigation strategies must recognize the effect of urbanization on hurricanes.
Weather and climate models must incorporate the effects of urbanization to increase forecast accuracy on local and regional levels.
“It is critical for the next generations of global climate models to be able to resolve the urban areas and their associated processes,” conclude the authors.
About the Authors and Models
The authors are:
Wei Zhang and Gabriele Villarini from the Department of Hydroscience & Engineering, The University of Iowa, Iowa City, IA
Gabriel A. Vecchi from the Department of Geosciences, Princeton University and the Princeton Environmental Institute, of Princeton, NJ
James A. Smith from the Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ.
To date, the role of a city in altering rainfall during tropical cyclones has received very little attention. Houston has had the largest urban growth and the fifth-largest population growth in the United States in the period from 2001–2011. Much of that growth is now on the periphery of the city. The two fastest growing parts of the region are Fort Bend and Montgomery Counties.
Also, the new NOAA Atlas-14 (rainfall measurements updated after Harvey) does not consider forward-looking urban growth effects. The precipitation frequency data in NOAA Atlas 14 was determined by a statistical analysis of historical rainfall, a key input for FEMA Flood Insurance Rate Map (FIRM) modeling. With all that uncertainty, we need to err on the side of caution in flood planning.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/02/KingwoodGreens-e1551452236612.jpg?fit=1500%2C1038&ssl=110381500adminadmin2019-08-18 20:39:572019-08-19 02:39:01Study Suggests Large Cities Like Houston Can Intensify Rainfall and Runoff From Hurricanes
Flood routing studies calculate when runoff from a new development will hit a river during a major rain event. If results show that the runoff will reach the river before the crest of a flood, developers may not need to build detention ponds. The idea: it’s not adding to the peak, so why run up costs needlessly?
Why Flood Routing Studies are Inadequate
In principle, that sounds good. However, routing studies almost always contain flawed assumptions according to Jeff Johnson, Montgomery County’s Engineer.
First, they don’t consider the cumulative effects of other developments. Second, they are almost always based on outdated hydrologic models. And third, they assume “ideal” storm conditions.
“If you start with a brand new hydrologic model,” says Johnson, “the modeling a developer does could theoretically be accurate.” But his/her runoff changes the model. That runoff rarely gets incorporated into the model that the next developer uses. “So the next developer is dealing with outdated assumptions,” says Johnson. Same way with the third and fourth developers, etc. They all keep going back to the original model, even though they know it has been changed by previous developments. Said another way, additional runoff is not added to the model on which subsequent developers base their calculations. So they all show no consequences when the cumulative effects can be large.
Another problem. They all base calculations on ideal assumptions. Johnson estimated that only a small percentage of storms conformed with ideal conditions. For one example, calculations are valid only if rain stops before the flood reaches its peak.
Shortage of Detention Leads to Downstream Flooding
As a result, there’s not enough detention upstream to protect downstream residents during a major storm.
Many developers like the flawed assumptions behind the routing studies. They justify building less detention, which costs developers time and money. And with less detention, they can develop and sell more lots per acre. So they reduce costs and increase income.
But when that happens, somebody downstream pays the price. “They’re not being responsible,” said Johnson. “This is a public safety issue.”
One flood expert that I interviewed for this article said, “Only good things come from more detention.”
City of Houston Public Works Director Agrees
As if to punctuate Johnson’s point, shortly after my interview with him, I attended a talk by City of Houston Publics Work Director Carol Haddock. Haddock emphasized that flooding today largely stems from problems inherited from legacy infrastructure. “We’re living with infrastructure developed before we knew what we now know about flooding,” said Haddock.
Haddock argued for both higher drainage and detention capacity. They will help accommodate future floods and future development – while protecting people and property downstream, she argued.
Projected MoCo Growth Underscores Need to Close Development Loophole
Getting drainage and detention right is crucial, not just for families downstream in northern Harris County, but also for families in Montgomery County itself. The New Caney ISD (NCISD) is projected to grow substantially in the next few years. The NCISD just completed a demographic update from Population and Survey Analysts (PASA). (Caution: 58 meg download.) Page 6 of the study shows that the District expects to grow by more than 19,000 housing units in the next 10 years. That’s almost as large as Kingwood. And it doesn’t even include commercial space.
In the previous 5 years, the NCISD had the second highest percent change in school district enrollment in the region at a whopping 30.3%. Only Alvin had a higher increase at 31.6%.
PASA predicts the new commercial area near 45 and 99 will have as much square footage as downtown Austin. And, further upstream, Conroe was the fastest growing City in America in 2017.
Fortunately, the new San Jacinto River Basin Survey will update hydrologic models. But with projected growth like this, they will become outdated as soon as they are complete. All the more reason to move away from the flood routing paradigm of development and require more on-site detention. ASAP.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/07/Growth-NCISD.jpg?fit=856%2C1160&ssl=11160856adminadmin2019-07-31 22:56:442019-07-31 23:00:03MoCo Will Consider Requiring More Detention for New Developments in August 27 Meeting