Tag Archive for: development

5-Year Rain Brings White Oak Creek Close to 100-Year Mark in Royal Pines

Between 1:00 and 3:00 PM on 1/24/23, approximately 3.6 inches of rain fell over Royal Pines in southeast Montgomery County. According to Atlas-14 rainfall tables, that qualifies as a 5-year rainfall event. But floodwaters from White Oak creek approached the edge of the 100-year floodplain. And missing silt fences let sediment escape into the wetlands that border the property.

5-Year Rain

A friend who lives a mile from Royal Pines recorded about 4″ on his rain gage for the full day. A check of nearby rain gages on the Harris County Flood Warning System, showed that the official gage at FM1485 and the San Jacinto East Fork recorded approximately 3.6 inches between 1 and 3 PM today.

Harris County Flood Warning System hyetograph shows approximately 3.6 inches fell in two hours on 1/24/23.

Cross-referencing that rate with NOAA’s Atlas-14 rainfall probability estimates for this area, we can see that 3.6 inches in 2 hours equals a 5-year rain.

atlas 14 rainfall probabilities
NOAA Atlas 14 rainfall probabilities for Lake Houston Area.

100-Year Flood Line

Now let’s look at how close that 5-year rain came to the 100-year flood line. In the construction diagram below, the developer shows the edge of the 100-year flood plain. It’s the dotted line between Zone AE and Zone X. I’ve circled the relevant portion in red.

If you were to project that line toward the lower right, it would roughly parallel the heavy black line that forms the eastern boundary of Country Colony, which you can see in the middle right of the photo below.

Floodwaters from Creek Overflow Royal Pines

The water comes almost to the edge of the floodplain shown in the construction diagram above.

Looking SE across Royal Pines. County Colony in upper right.

That big area filled with water, is a part of White Oak Creek cutting across Royal Pines. Think it’s just standing water? Think again.

The closer shot below shows water streaming through the soon-to-be subdivision and filling the Country Colony drainage ditch to overflowing.

Notice the water streaming through the cleared area and carrying away sediment downstream.

Notice also how the floodwaters approach what appears to be some sort of water treatment facility in the upper right.

These shots also document the absence of silt fence on the eastern side of Royal Pines.

All that silt will migrate down White Oak Creek and Caney Creek into the East Fork San Jacinto which the City of Houston just dredged at great public expense. The public also must foot the bill for increased water-purification costs.

From Harris County Flood Education Mapping Tool.

More Missing Silt Fence in NW Corner of Royal Pines

The SE corner of Royal Pines wasn’t the only part of the development missing silt fence. The developer removed it from the NW corner – where a neighbor has now flooded three times in two months.

Looking N toward White Oak Creek. Contractors removed the silt fence last week. Rain then swept sediment into the woods.

Those woods contain sensitive wetlands.

Notice how water coming from the north (left) is clear. But water coming from Royal Pines (right) is filled with sediment.
The muck filled the wetlands for more than a mile downstream.

How Can a 5-Year Rain Reach Almost as Far as a 100-Year Floodplain?

We need an answer to that question before this development starts pouring concrete. There are several possible explanations.

  • Clearcutting accelerated runoff.
  • Bulldozers compacted soil, limiting the rate of infiltration.
  • The developer hasn’t built any stormwater-detention-basin capacity to offset the increased runoff.
  • Planners used old (lower) Montgomery County rainfall data to determine the extent of the floodplain in their plats and plans.
  • Engineers didn’t count on the cumulative impact of insufficiently mitigated upstream development, some of which used beat-the-peak, hydrologic-timing surveys to avoid building detention basins.
  • The developer altered the landscape.
  • More rain fell upstream than at the gage shown above.
  • Some or all of the above.

I took these photos within an hour of the end of the rain. So there wasn’t much time for water to work its way downstream very far.

Two floodplain experts I consulted pointed to the cumulative impact of upstream development as a possible culprit. Engineers are likely working with flood data acquired in the 1980s before Montgomery County became one of the fastest growing counties in the region. The data is simply too complex to adjust after each new development. So, it never gets revised and errors compound over time.

I’m sure the Montgomery County Engineers Office and TCEQ will want to get to the bottom of this before the developer starts building homes. If homebuyers flood on rains that are far less than 100-year rains, tremendous liabilities could result.

When Perry Homes attempted to build Woodridge Village – only one-half mile from Royal Pines – its engineers pretended no floodplains existed. That cost Perry Homes millions of dollars and its reputation.

If Royal Pines or Montgomery County would like to rebut the issues I’ve raised, I will be happy to publish their point of view. The public deserves to know what’s going on.

Posted by Bob Rehak on 1/25/23

1975 Days since Hurricane Harvey

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

Development Update on 3 Areas in NW Humble

Three areas in northwest Humble are in various stages of development. Parts or all of these areas flooded during Hurricane Harvey. The flooding was deep enough that reportedly one of the developers is not even going to try to raise the area. Instead, he said he will raise the homes 6-7 feet. Let’s hope that’s enough.

The numbers in the satellite image correspond to the groups of photos below. I took all shots on 1/3/23.

#1 will become light industrial. #2 will become single family residential. #3 will become single- and multi-family residential.

Area #1 – Light Industrial

According to a 2016 map by Skymark, the developer, the first area will become light industrial.

A four-lane divided road leads from the NW corner of Townsen Boulevard to Spring Creek on the north. By Skymark Development.
The road abruptly stops before reaching Spring Creek and the Spring Creek Nature Trail.

The unpaved area between Spring Creek and where the road ends is owned by another developer (Pacific Indio) who also owns the land on the far side of the creek.

The Spring Creek Nature Trail cuts through the woods near the creek and follows it north toward I-45.
Reverse angle shot looking SE toward Deerbook Mall shows large cleared area with stormwater detention basin.

Area #2 – Single Family Residential

Contractors are in the process of building roads into an area west of Target and Kohls. Saratoga Homes reportedly plans to build 357 homes and townhomes on this location.

Looking S from over Townsen Blvd. we can see two large stormwater detention basins (lower and upper left)
Same area, but looking east toward Kohls and Target.

The closer shot below shows that not all the roads have been built yet.

Saratoga plans to build elevated homes here.

Area #3 – Single- and Multi-Family Residential

Looking south toward Sam’s with Townsen Blvd West on right, we can see a large stormwater detention pond that already has grass growing. This area will become single- and multi-family residential, some of which will be dedicated to seniors.

Note last of trees in center foreground being cleared and shredded for mulch.
Spillway from detention basin seems to have a detour built into it. The purpose? Likely to slow the water and avoid erosion at the base of the utility poles. The long ditch on the left will drain Areas 2 and 3.

Together, all three areas comprise approximately 260 acres according to this map on the Skymark Development website.

To learn more about the history of these sites, see the posts below. They contain floodplain and wetland maps.

Onward. Into the danger zone!

Posted by Bob Rehak on 1/9/23

1959 Days since Hurricane Harvey

Royal Pines Clearcutting Floods Neighbor on Less Than 1″ of Rain

As proof of how dangerous clearcutting without sufficient mitigation can be, the controversial Royal Pines development has flooded a neighbor on a rain that was less than 1″ – even as the Lake Houston area flirts with drought.

Royal Pines sits at the northern end of West Lake Houston Parkway in Montgomery County. Looking SE from NW corner on 10.31.22.

The circumstances are similar to those of a nearby development – Woodridge Village. There, clearcutting flooded Elm Grove Village and North Kingwood Forest twice in 2019. Without sufficient detention basins, sheet flow from approximately 268 acres swept through hundreds of homes. But those incidents weren’t during a drought. And the rainfalls were much heavier.

Less than an Inch of Rain

In this case, the rain fell on October 28, 2022. Harris County’s Flood Warning System recorded a peak of .72 inches of rain in an hour at the nearest gage. To put that in perspective, .72 inches is so slight that it would have had to have fallen in five minutes to qualify as a five-year rain or ten minutes to qualify as a one-year rain.

atlas 14 rainfall probabilities
NOAA’s Atlas 14 rainfall probabilities

However, the rain was spread out over about a half hour.

From Harris County Flood Warning System for West Lake Houston Parkway gage on 10/28/22.

And the soils were not saturated either. The Lake Houston Area has been in drought for much of the year. As of 11/5/22, the US Drought Monitor rated this area “abnormally dry.”

From US Drought Monitor

During the entire month before October 28, the area had received only a little more than a half inch of rain.

From Harris County Flood Warning System for month before rain in question.

Sloping Land Toward Neighbor’s House

The flooding occurred in the northwest corner of the new development. From pictures and emails supplied by the neighbor, aerial photos taken during the last several months, elevation profiles obtained from the USGS national map, and construction plans obtained via a FOIA Request, I’ve been able to piece together the following. It appears that:

  • Montgomery County asked the developer to revise its plans for a detention basin.
  • Before approval of the revisions, contractors clearcut 200+ acres.
  • Contractors filled in a natural depression that channeled runoff toward White Oak Creek and sloped the development toward the neighbor’s home.
  • Runoff from the .72-inch rain rushed toward the northwest corner of the development.
  • Silt fences funneled most of the runoff toward the corner, where it broke through the fence.
  • Runoff also seeped under the fence.
  • The runoff washed sediment across the back of the neighbor’s property toward White Oak Creek.

See the YouTube video below.

Video shot by resident on 10/28/22
Sloping mudline on silt fence shows how land had been angled toward this corner. The lower elevation used to be to the right. See discussion below.
Water and muck running onto neighbor’s property through break in corner. Water also ran underneath silt fence.
Aerial photo taken five days later on 11/2/22. Notice all the muck still in the corner and the silt deposited in the woods.

The neighbor’s property extends on a straight line beyond the left fence. Water flowed from bottom of frame toward corner.

Wider shot taken after the rain on 11.2.22 shows contractor tried to fill in trench eroded by runoff.
On 11.5.22, contractors repaired the silt fence and installed additional silt fences to slow and block runoff.

Luckily, the neighbor’s house did not flood. But a heavier rain might have flooded it.

Development Now Slopes Toward Neighbor Instead of Away

The USGS National Map shows that this area used to slope AWAY from their property, NOT TOWARD it.

Left side of image shows contour (brown line) from USGS National Map before land was cleared. Right side shows area east of the resident’s home used to slope down more than 7 feet in about 250 feet.

In this area water flows from the bottom of the frame toward the top where White Oak Creek is. Comparing the contours on the left above and depression on the right with the direction the water actually travelled confirm that contractors altered the slope of the land.

Yet Chapter 11.086 of the Texas Water Code begins “No person way divert … the natural flow of surface waters in this state, or permit a diversion … that damages the property of another …”

Missing Detention Basin

Construction plans show that the developer was supposed to have built a detention basin in the corner that flooded.

Royal Pines
Royal Pines construction plan shows detention basin in northwest corner. Also note same contour shown on USGS map above.

However, the Montgomery County Engineer’s Office has reportedly asked for changes to the design of the detention basin. A sound business practice would have been to avoid clearcutting that area until the basin could have been excavated immediately.

Montgomery County does not require the approval of construction plans before clearcutting. This story shows why that should change. Delays expose people to more flood risk.

Normally, October is the second rainiest month in Houston. We average 5.46 inches.

Clearly, the flooding shown in the pictures below could have been much worse in a normal year.

Let’s hope they get that stormwater detention basin built before heavier rains return! And let’s also hope that other contractors learn this clearcutting lesson.

Posted by Bob Rehak on 11/6/2022

1895 Days since Hurricane Harvey

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

Mavera Clearing More Land West of FM1314

The Pulte Homes Mavera development at FM 1314 and SH 242 comprises approximately 2000 acres. Contractors first focused on clearing the 865 acres east of FM 1314. Photos taken on 7/22/2022 show they’re now also focusing on the 1150 acres west of FM 1314. Significant clearing in this western portion has already occurred. But more remains.

Map of Mavera At Ultimate Buildout

Map excerpted from developer’s 5/29/2020 memo to Montgomery County engineers.

Photos From West to East

Looking west from middle of western portion of Mavera. SH 242 in background. Channel drains into Crystal Creek which drains into West Fork San Jacinto by sand mine ponds in upper left.
Looking south from same position. SH 242 cuts left to right through upper middle of frame. Ponds in background are sand mines bordering the San Jacinto West Fork.
Looking east from same position at drainage coming from eastern portion of same development in distant background.
Moving farther east toward FM 1314. Still looking east. SH 242 cuts diagonally from middle right toward upper left.
Intersection of FM 1314 (bottom) and SH 242 (right). Looking east toward first section cleared and drained.
Eastern-most section of Mavera. Looking NE.

Hydrologic Timing Used to Reduce Detention Requirements

While Mavera will provide some linear detention in the main channel along with some small ponds, it relies heavily on a hydrologic timing study to avoid building all the floodwater detention capacity normally associated with a development of this size.

Hydrologic timing studies attempt to show that a development can get stormwater to a river, such as the West Fork, before the peak of a flood arrives. The theory: if you aren’t adding to the peak, you don’t need as much detention.

However, Harris County discourages the use of hydrologic timing. It encourages developers to get their water to the river as fast as possible. If enough developments do that, it can shift the peak. Regardless, Montgomery County still allows it.

In a hundred-year (1% annual chance) flood, this development claims it will not add to the peak. And therefore, it will have no adverse impact downstream. Yet it alone sends more than 16,300 cubic feet per second downstream toward West Fork sand mines and the Humble/Kingwood Area. That represents about 10% of the water that came down the West Fork during Harvey at this location.

Posted by Bob Rehak on 8/2/2022

1799 Days since Hurricane Harvey

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

Mythbusters: Common Misperceptions about Flooding in Harris County

Since Hurricane Harvey, I’ve continually run into several widely held misperceptions about flooding in Harris County. As we head into another hurricane season, let’s set the record straight about the most common myths. Some of the facts below have been adapted from information provided by the Harris County Flood Control District.

MYTH: The Harris County Flood Control District is responsible for addressing all types of flooding.

FACT: The Harris County Flood Control District is responsible for bayous and many of their tributaries. However, the City of Houston, other municipalities, and Precincts – in unincorporated Harris County – handle storm sewers and roadside ditches.

street flooding

The Texas Department of Transportation handles drainage of highways and their feeder roads.

The moral of this story: make sure you call the right people when you see a problem developing.

MYTH: I’ve lived in my house for more than 30 years and I’ve never flooded. Therefore, I don’t need flood insurance.

FACT: Most Harris County residents live in homes vulnerable to flooding because:

  • Our topography is flat.
  • Many of us have impermeable clay soils that increase runoff.
  • Our subtropical climate can produce large amounts of rain in short periods of time.

Storm rainfall patterns may have spared your area since you have lived there. But that could change like the weather.

Remember. People thought Tropical Storm Allison was the worst. It caused all the flood maps to be revised. Then along came Harvey. Now, HCFCD and FEMA are revising the flood maps again.

During Harvey, more than 68 percent of the homes that flooded in Harris County were outside the 100-year flood plain. So, consult your insurance agent. Most homeowner insurance policies do not cover flooding. You need a separate policy for that.

MYTH: A 1-percent (100-year) flood occurs only once every 100 years.

FACT: A 1-percent (100-year) flood can occur multiple times throughout a century. A 100-year flood has a 1-percent chance of occurring in any given location in any given year. Doesn’t sound like a lot? Think of it this way: A home in a 1-percent (100-year) floodplain has at least a 26-percent chance of flooding during a 30-year period of time – the duration of many home mortgages. And remember, Harris County experienced four hundred-year events in four years (Tax Day, Memorial Day, Harvey, and Imelda).

MYTH: I only need to worry about flooding during hurricane season.

FACT: Flooding can happen any time of the year. Of the four storms mentioned above, two occurred outside of hurricane season.

Short, high intensity rainfalls can cause street flooding that invades vehicles and homes built close to street level or near developments with insufficient mitigation.

Hundreds of homes flooded in Elm Grove on May 7, 2019. The causes: 5.64″ of rain in about 12 hours. And a 270-acre tract upstream that had recently been clearcut with only 9% of the promised detention ponds constructed.

high water rescue truck
High water rescue truck on flooded Elm Grove Street, May 2019
MYTH: If I didn’t flood during Allison or Harvey, chances are I won’t ever flood.

FACT: The greatest rainfall brought by Tropical Storm Allison hit the northeast part of Houston and Harris County, dropping more than 28 inches of rain in 12 hours and 35 inches of rain in five days. However, some areas received fewer than 5 inches of rain. Had the damaging rains of Allison targeted other areas, they would have experienced similar, devastating flooding.

Harvey also hit and missed certain areas. But the differences were even more dramatic. While Friendswood received 56″ of rain, Willis in Montgomery County received only 5″ between August 25 through September 1, 2017. See USGS, Table 1, Page 3.

MYTH: I don’t need flood insurance because I don’t live in a mapped floodplain.

FACT: We are all at risk for flooding regardless of our proximity to a mapped floodplain. Flood Insurance Rate Maps (FIRMs or floodplain maps) published by the Federal Emergency Management Agency are good indicators of flooding risks from bayous and creeks overflowing their banks. However, they do not show flooding risks from storm sewers and roadside ditches exceeding their capacity, risks from unstudied bayous and creeks, or risks from storms greater than a 0.2 percent (500-year) flood — such as Tropical Storm Allison in 2001 or Hurricane Harvey in 2017.

MYTH: New land development causes flooding.

FACT: New development can accelerate the time of concentration of floodwaters, contributing to faster, higher flood peaks. That’s why cities and counties regulate development. But some see lax regulation and enforcement as a tool to attract new development. And even those with strict regulations may find that they aren’t strict enough to handle storms of increasing intensity.

HCFCD graph showing effect of development in Brays Bayou watershed. Insufficiently mitigated development over 85 years accelerated runoff, building flood peaks faster and higher.

Flooding can be inherited from areas developed before our understanding of flooding improved. So it would be safer to say that “Insufficiently mitigated development causes flooding.”

Regulations dating to the early 1980s in many areas require stormwater runoff after development to be no greater than runoff before development. Developers must detain any excess stormwater on site. However:

  • Development prior to the 1980s was not as regulated.
  • Our understanding of what constitutes a 100-year rainfall continues to evolve. So pre/post estimates may be off.
  • Loopholes exist in many jurisdictions that allow developers to avoid building detention ponds.

Today, we have a hodge-podge of regulations throughout the region. Learn regulations in your area and monitor new developments to ensure compliance.

MYTH: A storm surge from a tropical storm or hurricane will inhibit our bayou system’s ability to drain.

FACT: Most of our bayous and creeks are upland and drain by gravity. Because of their natural slope toward Galveston Bay, a storm surge caused by a tropical storm or a hurricane will not impede this process. Of the roughly 2,500 miles of bayous and creeks in Harris County, only a small portion near Galveston Bay will be influenced by storm surge for a short period of time.

Posted by Bob Rehak on 6/20/22 with thanks to the Harris County Flood Control District

1756 Days after Hurricane Harvey


Top Stories of 2021 in Review

Below are my personal picks for the top flood-mitigation stories of 2021.

The Fight for Funding

In 2019, Commissioners Court established “equity” guidelines that prioritized projects in Low-to-Moderate Income watersheds. Then this year:

Still no word from HUD on a possible direct allocation of $750 million. We may hear in January.

To help you follow this story, I make quarterly FOIA requests for Harris County Flood Control District spending and post the analyses on a dedicated funding page.

Sand-Mining Best Management Practices

Activists led by the Lake Houston Area Flood Prevention Initiative and the Bayou Land Conservancy petitioned the Texas Commission on Environmental Quality (TCEQ) to establish best management practices for sand mines in the San Jacinto watershed. We didn’t get everything we wanted, but we got a vast improvement over what we had. And the new BMPs may help reduce erosion that contributes to future floods in this area.

West Fork Sand Mine illustrates need for vegetative controls to reduce erosion.

Relentless Development

Fueled by low interest rates and flight from city crowds during Covid, suburban and rural development surged in 2021. Flood-mitigation felt like an afterthought in many developments. We saw that with Colony Ridge in Liberty County. Colony Ridge clearcut wetlands, paved over floodplains and ignored county regs designed to reduce erosion.

In the Kingwood Area, the Laurel Springs RV resort took advantage of a grandfathering clause in permitting to build a detention pond one-half the size of current requirements. These represent just two examples of many.

The Laurel Springs RV Resort got its detention pond approved one day before stiffer regs went into effect.

After Harvey, we saw how such practices made flooding worse. How soon we forget!

Houston Housing and Community Development Meltdown

Houston’s Housing and Community Development Department, which was responsible for distributing more than a billion dollars in Harvey disaster relief funds, came unglued again this year. Last year, it sued the Texas General Land Office to keep money it couldn’t give away. This year, the Department’s Director publicly denounced the Mayor of Houston for trying to steer multi-family housing subsidies to the Mayor’s former law partner. The Mayor claimed ignorance of the partner’s involvement and announced a City Attorney investigation which never materialized.

Meanwhile, flood victims were victimized a second time. Bureaucratic bungling denied aid to people who deserved it.

World War II And Lake Houston Gates

May 9, 2021, was 1349 days after Hurricane Harvey ravaged Texas and the Gulf Coast. That’s the number of days it took the US and its allies to win World War II. But during that time we’ve had few victories in the fight against future flooding in the Lake Houston Area with the exception of dredging, So far, we’ve mainly completed studies. And many of those are still in the works.

For instance, the City of Houston has been studying ways to increase the release capacity of the Lake Houston Dam. Right now, the release capacity is one-fifteenth that of the gates on Lake Conroe. That makes it difficult to shed water quickly before and during floods. FEMA gave the City money to study the problem, but is still finalizing recommendations. The City hopes to make an announcement in January.

Lawsuits

The Lake Conroe Association had its lawsuit against the SJRA thrown out of court…with prejudice. The LCA hoped to prohibit the SJRA’s policy of seasonal lake lowering, which was designed to help protect the Lake Houston Area until other flood mitigation efforts could be put in place.

The Texas Attorney General is still suing the Triple PG Sand Mine in Porter on behalf of the TCEQ. There has been little movement on the case in the last 18 months. The mine’s owner changed legal counsel in July 2020. A TCEQ representative says the AG has not given up. The two sides are still in discovery.

Approximately 1700 homeowners in the Lake Houston Area sued sand mines for contributing to flooding during Harvey. The cases were consolidated in the 281st Harris County District Court under Judge Sylvia Matthews. She recently set deadlines in the first half of next year for motions, depositions, joinder, expert witness testimony and more. The case is known as “Harvey Sand Litigation.”

Various lawsuits against the SJRA for flooding during Harvey are still working their way through the legal system.

Kingwood residents reached a settlement with Perry Homes, its subsidiaries and contractors this year over two floods that damaged hundreds of homes in Elm Grove and North Kingwood Forest during 2019. The incidents had to do with development of Woodridge Village, just across the Harris/Montgomery County line.

Woodridge Village

Harris County Flood Control District purchased Woodridge Village from Perry Homes in February this year and hired a contractor to begin doubling the current floodwater-detention capacity on the site. When complete, the additional capacity will help protect homes in Elm Grove, North Kingwood Forest and downstream along Taylor Gully.

Expansion of Dredging

After three and a half years of dredging in the San Jacinto West Fork, dredging has now moved to the East Fork. State Representative Dan Huberty secured $50 million earlier this year to extend the dredging program to other inlets around Lake Houston in the future.

East Fork Dredging. Photographed in early December between Huffman and Royal Shores in Kingwood. Looking south toward Lake Houston.

Bens Branch and Taylor Gully Cleanouts

In Kingwood, HCFCD finished excavating both Bens Branch and Taylor Gully to help restore their conveyance. Through gradual sediment built up, both had been gradually reduced to a 2-year level of service in places. That means they would come out of their banks after a 2-year rain.

Final phase of Bens Branch maintenance between Kingwood Drive and Rocky Woods. Note Kingwood High School in upper right.

Subsidence

Years of fighting over subsidence between the Lone Star Groundwater Conservation District and Groundwater Management Area 14 came to a head earlier this year. LSGCD fought any mention of subsidence in Desired Future Conditions (DFCs) for Montgomery County. GMA-14 wanted to include it, but finally recommended allowing each groundwater conservation district to make a subsidence measure optional. Unlimited groundwater pumping in southern Montgomery County could tilt Lake Houston toward homes at the northern end of the lake. That’s because subsidence would be greater there than at the Lake Houston Dam by TWO FEET.

GMA-14 will take a final vote on January 5 on the final DFCs. You still have time to protest.

Posted by Bob Rehak on 12/31/2021

1585 Days since Hurricane Harvey

Spring Creek Greenway Threatened by New Development

One of the most popular natural attractions in the north Houston area is the Spring Creek Greenway. But between mile marker 8 and 8.5, a large new development called Breckenridge East has cut across the trail, leaving a massive scar through the forest to accommodate its drainage.

Nature Interrupted

Since 1979, Harris County Precinct 4 commissioners have added to the beautiful trail system between I-69 and I-45. The Spring Creek Greenway currently connects and protects approximately 7,000 acres of forest in Harris County, preserving this ecological gem as a mecca for ecotourism, education, and outdoor recreation.

But yesterday, a reader and cyclist, Ken Matthews, alerted me to an issue.

Photo by Ken Matthews on 10/31/2021. Taken from Spring Creek Greenway looking toward new development.
NE portion of development from the air. Oval indicates where it cuts across greenway. Spring Creek cuts through top of frame from left to right.

Role of Forests in Flood Prevention

According to Harris County Precinct 4 and Harris County Flood Control District:

  • Forests buffer against flooding by absorbing rainfall in their canopies and in the soil.
  • Trees act as natural water filters and significantly slow the movement of storm water, which lowers runoff, soil erosion, and flooding.
  • From an economic viewpoint, communities that use this important function of trees and canopy cover may spend less money on other flood control methods.

Infiltration rates for forested areas are 10-15 times greater than for equivalent areas of turf and grass.

Harris County Flood Control District

Recipe for Runoff

In the shot above, you can see the beginning of what looks like a large detention pond. But as we saw with Woodridge Village flooding in 2019, putting in the detention ponds AFTER the land has been cleared can be a recipe for runaway runoff during big storms.

Lush forest replaced by vast expanse of sterile nothingness.
Entire development. A local resident told me that during Harvey, water came up to Cypresswood Drive in the lower left. That put this entire area underwater.
Breckenridge East is in far upper left. Another development a little more than a block away is also cutting into the forest. Cypresswood Drive in foreground.
Looking NW from second development across Planet Ford Stadium toward Breckenridge East, one can see a whole series of developments starting to encroach on the Spring Creek floodplain and greenway.

Support Bayou Land Conservancy

The Bayou Land Conservancy (BLC) plays a vital role in protecting and maintaining the Spring Creek Greenway, which is the longest, contiguous, urban forested corridor in the country.

When finished, the Greenway will ultimately:

  • Stretch over 40 miles,
  • Reach from Highway 249 in Tomball east to US 59 in Kingwood, and 
  • Cover more than 12,000 acres. 

Please support the Bayou Land Conservancy. They preserve land along streams for flood control, clean water, and wildlife. Not to mention future generations.

Posted by Bob Rehak on 11/1/2021 with thanks to Harris County Precinct 4, Bayou Land Conservancy and Ken Matthews

1425 Days since Hurricane Harvey

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

Clean Water Act, R.I.P.

Confluence of Spring Creek (left) and San Jacinto West Fork (top) on March 6, 2020. The Montgomery County line cuts left to right through the center of this picture at the tip of that white sand bar.

If the Clean Water Act were still being enforced, we might see scenes like this less often. You’re looking at the confluence of Spring Creek and the San Jacinto West Fork. It has looked like this during random flyovers in four out of the last six months.

Clean Water Act Abuses

Only after the infamous and extreme white-water incident in November last year was West Fork pollution reduced briefly. The white-water episode was so egregious that it attracted network television attention and prompted a crackdown by the TCEQ. TCEQ cited Liberty Materials in Conroe for allegedly discharging 56 million gallons of white goop into the West Fork. The discharge had 25 times the normal level of suspended solids in it.

Liberty isn’t the only sand mine on the West Fork. You can find approximately 20 square miles of sand mines in the twenty mile stretch between I-69 and I-45. Spring Creek on the other hand has only one mine – almost 30 miles upstream at SH249.

Most West Fork mines have a tendency to leak waste water from time to time. That’s part of what you see in the photo above. Below are seven NEW breaches spotted this month upstream on the West Fork.

Mine water leaks into wetlands and out past perimeter road at LMI E. River Road mine in Conroe.
Pumping water over dike at same Liberty Materials Mine on River Road.
At same mine, a pipe through the dike discharges water at a fixed height into an adjoining ditch that leads to the West Fork.
Liberty Materials leaks water into backyard of home in Bennett Estates. From here it goes into a storm drain on Calhoun and into the river.
Difficult to see at this resolution, there’s a pump in front of the trees on the left. It’s sending waste water into the wetlands below the mine.
Hallett sprouts another leak into the West Fork (lower right).
Most of these breaches happen out of sight and never get reported.

MoCo Tax Breaks for Polluters

Why such a high concentration of mines on the West Fork? It might have something to do with tax breaks by the Montgomery County Appraiser’s Office which passes out ag and timber exemptions for industrial cesspools. That’s contrary to how the State Controller says MoCo should appraise the mines. But nobody at the state level seems to put much pressure on MoCo.

Construction Practices Muddy Clean Water Act, Too

Another part of the West Fork turbidity problem is upstream construction in Montgomery County. Believe it or not, Montgomery County starts at the tip of that white sand bar at the confluence of Spring Creek and the West Fork.

Sediment control is not a high priority for MoCo developers. Nor is enforcement a high priority for MoCo. In fact, the East Montgomery County Improvement District actively advertises its LACK of rules as a way to lure developers.

That’s how you get construction practices like those in the new 2200 acre Artavia complex going in next to the West Fork sand mines, just south of SH242 by FM1314. Brand new culverts are already clogging. See below.

Artavia drainage ditch and culverts. A river of mud.

More on Artavia in a future post.

The erosion is so bad, even the erosion is eroding in many places.

Decline of Clean Water Act

Then, of course, another part of the problem is the gutting of the Federal Clean Water Act. States, counties and municipalities used to have someone setting standards and looking over their shoulders. The rollback of key provisions, such as the redefinition of “waters of the U.S.”, has been heralded as a boon to developers and the death knell of wetlands.

Just last week, we saw the Army Corps rule that the wetlands on Perry Homes Woodridge Village property did NOT fall under their jurisdiction, so there was no violation of Section 404 of the Clean Water Act.

Of course, you don’t have to change regulations to kill them. You can just not enforce them. By turning a blind eye. Gutting enforcement staff. Overruling staff. Reinterpreting policy. Ignoring evidence. Or resetting priorities. To name just a few.

Don’t Know What You Got Till It’s Gone

Many of us who grew up before the Clean Water Act (formerly known as Federal Water Pollution Control Act, passed in 1972) remember how bad things were. Like the Cuyahoga River fire in 1969.

The San Jacinto West Fork has already been named one of the most endangered rivers in America. But my biggest fears are not for the river. They’re for the health of the millions of people who depend on water from the river. For the people who will flood when the river becomes clogged with sediment. For the poor and elderly who can’t afford sky high bills to cover the cost of water treatment. And for the long-term health of the economic hub of the region, Houston.

Posted by Bob Rehak on 3/14/2020

928 Days after Hurricane Harvey

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

MoCo Will Consider Requiring More Detention for New Developments in August 27 Meeting

Montgomery County commissioners will consider changing flood mitigation requirements for new developments at their regular August 27 meeting. Commissioners will hear public testimony and consider approving a revision to the Montgomery County Drainage Criteria Manual. The change would close a loophole that allows developers to substitute “flood routing studies” for detention ponds in new Montgomery County developments. 

How Developers Use Flood Routing Studies

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.

A graphic from a Caldwell Brokerage brochure shows some of the major current and planned developments in the area between the Woodlands and Kingwood with the number of homes.

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 graphic comparing 5-year growth rates in area school district enrollments.

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.

Register Your Opinion

Expect developers to testify against closing the “flood routing study” loophole. You can testify for closing it, however. Montgomery County Commissioners will hear public testimony at their regular meeting on August 27th. The meeting starts at 9:30. Montgomery County has special sign-up procedures for citizens who wish to testify; make sure you sign up beforehand. Check the agenda beforehand to plan your time. You can also register your opinion with county commissioners via phone or email.

Posted by Bob Rehak on 7/31/2019

701 Days since Hurricane Harvey

Dangers of Erosion when Developing Floodplains

A resident of The Commons on Lake Houston contacted me about some severe erosion in her community. I can only describe it as stunning. It destroyed trails owned by the Property Owners Association that people used for hiking, biking and horseback riding. The loss of these trails limits recreational opportunities and has physically divided large parts of the community.

Sadly, it didn’t have to be that way. Infrastructure and ditch maintenance did not keep pace with development.

As development crept closer to the East Fork of the San Jacinto over the years, the erosion worsened. In older neighborhoods on higher ground, a series of small check dams in a major drainage canal reduced erosion.

A check dam is a small dam constructed across a drainage ditch to counteract erosion by reducing water flow velocity. 

Wide grassy, gentle slopes and check dams keep erosion at bay in areas first developed.
The last check dam. Downstream, it’s different. 

Below Check Dams, Uncontrolled Erosion

The dams stop short of the East Fork. A tiny swale that residents used to step over has expanded into a steep-sided gully approximately 20 feet deep and 50-75 feet wide. Not even concrete can stop the erosion now.

Concentrated runoff below the check dams has peeled away concrete used to reduce erosion around this pipe.

Trails used to run alongside and across this ditch. Now they’ve been swallowed. Residents have nicknamed the ditch “The Grand Canyon.” They fear walking near the edge because of potential for cave-ins.

Water exits the other side of the pipe with the force of a fire hose. It has eroded a huge bowl, now eating trails and trees.
Further downstream, a shallow ditch has turned into what residents now call “The Grand Canyon.”
Resident points to where part of a horseback riding trail caved in.
Trees falling into the center force the water wider during floods, worsening erosion.
This tree created an eddy that ate away a foot path. It went from lower left to upper right.

Causes of Erosion

Erosion can result from many things. Multiple factors played a role in the Commons.

As the developer built up land to elevate foundations, he increased the slope. That accelerated runoff.

Clearing land for a new subdivision along the ditch also accelerated erosion of soft, sandy soil.

Finally, concentration of runoff also played a major role. When runoff spreads out over over acres, it poses no threat. But concentrating it turns a thousand trickles into a firehose aimed at loose, sandy soil. The result: severe erosion every time it floods.

Residents of The Commons have already seen how that erosion can destroy recreational opportunities and infrastructure. They pray that their developer will fix the Grand Canyon before it starts eating homes.

Lessons for Kingwood

This Commons story contains timely lessons for the residents of Kingwood as we consider a potential high-rise development in the floodway and floodplain of the San Jacinto.

The Commons erosion reminded me of the Kingwood Rapids. Whitewater enthusiasts gave that name to the drainage ditch that runs between Kingwood and Forest Cove near Deer Ridge Park, just south of Walnut Lane (see below).

The drainage ditch between Walnut Lane and Deer Ridge Park has jokingly been dubbed the Kingwood Rapids by whitewater enthusiasts. Ditch erosion now threatens yards and fences. Image courtesy of Google Earth.

The proposed new high-rise development would use this ditch to drain hundreds of acres that they intend to pave with concrete.

“Kingwood Rapids” in 2009 shows same processes at work here that threaten the Commons.

High-Rise Concern: Erosion and Incision

As you can clearly see, the ditch can barely handle existing runoff during storms. It’s severely eroding.

Draining high-rise, high-density commercial space into these ditches will cause them to “incise.” Incise means “cut into.” Runoff will deepen and/or widen ditches. But ditch erosion already threatens nearby homes.

This same ditch runs through River Grove Park, which already cost Kingwood residents more than half a million dollars in repairs after major storms in 2015, 2016 and 2017. The soccer program at River Grove still has not fully recovered. The lacrosse league has abandoned its lease there. One shudders to think of the damage that the loss of River Grove to do to the entire community.

Impact on Water Quality

All this erosion also has a direct impact on water quality in several ways. First, the sediment flows into the lake. There, it reduces lake capacity. The sediment also increases turbidity, which increases water treatment costs and harms riparian vegetation. That vegetation helps stabilize banks, protect property and provide cover for fish which waterfowl and eagles feed on6

More food for thought as you compose your letters to the TCEQ and Army Corps.

Posted by Bob Rehak on 1/16/2019

506 Days since Hurricane Harvey