Northpark woods Archives - Reduce Flooding

Editorial: Need More Disclosure, Education About Flood Risk

Who teaches young home buyers about flood risk? No one in my experience.

More than forty years ago, I bought a new house next to a creek in a Dallas suburb. The trees and the view attracted me. Before I put money down, I asked about flooding and was assured that the home was two feet ABOVE the hundred-year flood plain. The homebuilder even showed me a survey and a drainage study, and pointed to the engineers’ stamps. I pulled out my checkbook and made the most tragic, costly decision of my young life.

Within a year, other developers just upstream from me built the Collin Creek Mall and Plano became the fastest growing city in America. With each passing month, rains made the creek swell higher. Then one day after a modest rain, I saw a pickup truck floating down the creek and the water creeped into my house.

Alarmed, I called the City Engineer. He convened a task force that included Garland, Richardson and Plano City Engineers. They asked the Army Corps of Engineers to re-survey the creek. The Corps found that…

…instead of being two feet above the 100-year floodplain, we were now 10 feet below it.

Had I known such dramatic change could happen so quickly, I never would have bought the home. I decided to sell, disclosed the flood risk, and lost a pile of money.

Costly Lessons Learned

That experience taught me several lessons.

Flood forecasting is a very inexact science. Changing conditions – such as upstream development, climate and political priorities – make it so. They are beyond the ability of engineers to predict.
Developers use the surveys and analyses that engineers produce to obtain building permits.
Their documents do not reflect the potential for future change.
Homebuilders, nevertheless, use the engineering documents to reassure future buyers that they are safe.

All along the way, people throughout the value chain make expensive binary decisions based on documents that don’t reflect future flood-risk. Permit or don’t? Invest or don’t? Build or don’t? Lend or don’t?

Flood Risk is Non-Binary, Flood Education Non-Existent

Professionals understand the flood risks involved. Members of the public rarely do. And that’s a powerful argument for flood-risk education and fuller disclosure.

But buy a house with a view of a river! You’ve achieved the American Dream, paid a premium, and the only information people volunteer along the way is a reminder to buy flood insurance.

It’s as if the chance of flooding equals the chance of getting hit by lightning.

According to the CDC, the odds of being struck by lightning in a given year are only around 1 in 500,000.

But the odds of flooding in a “500-year rain” are 1 in 500 – a thousand times greater. But most home buyers don’t worry about that. So builders keep building in flood plains. And buyers keep buying.

Everyone along the way – land owners, developers, public officials, engineers, and home builders – is financially incentivized to “make the sale.” Growth is good – especially to the people who enable it.

Example: Need for Flood-Risk Education

Below is a photo that shows part of a new development in Porter between Sorters-McClellan Road and the San Jacinto West Fork. At the start of 2019, it was all woods and wetlands bracketed by streams and a drainage ditch. Wetlands and the proximity to floodways increase flood risk.

*New woodless Northpark Woods development in the floodplain of the San Jacinto West Fork.*

However, FEMA’s current flood map (see below) was developed in 2014. That was before Harvey. It shows about half of the development (outlined in red) to be in the 100- or 500-year floodplains. But those floodplains will soon expand based on data collected after Harvey. The new flood plains will likely cover most of the site. But is anyone disclosing the current or potential flood risk?

*Northpark Woods highlighted in red. Floodplains delineated based on 2014 map which is now being revised and will be released soon.* *Cross-hatch = floodway. Aqua = 100-year floodplain. Brown = 500-year floodplain.* From FEMA’s National Flood Hazard Viewer.

Selling the Dream vs. Disclosing Risk

Young, first-time home buyers will mortgage themselves to the hilt to get a nice home with a water view. But there’s less risk disclosure on this developer’s website than on the back of a candy bar.

New homes here range from $225,000 to more than $300,000 with estimated mortgages starting at about $1,000 per month. The developer claims, “Our homes are where memories are made, families are raised and stories unfold. Our mission is to create thriving, enduring neighborhoods by building new homes with lasting livability.”

The developer’s website also boasts of “close proximity to the West Fork San Jacinto River where locals enjoy swimming, fishing, boating and skiing…” And they brag about nearby championship golf courses, owner financing, online buying, and $95 down. But they never mention flood-risk or even flood insurance once the website that I could find.

A home in the 100-year floodplain has, on average a 1-in-4 chance of flooding during the life of a 30-year mortgage. And keep in mind that those floodplains are shifting targets. Even a home in the 500-year floodplain has a 6% chance of flooding in 30 years.

All up and down the West Fork, East Fork, Bens Branch, Spring Creek, Peach Creek, White Oak Creek, Luce Bayou, Tarkington Bayou, and other area watersheds, similar developments are sprouting up in risky places.

People put their life savings in these homes and there’s less disclosure than on a candy bar.

Realistically, that’s not going to change. So “Buyer Beware”! People must educate themselves about flood risk. Start by referring friends and relatives in the market for a home to these posts. They explain where to find reliable, objective information about flooding and flood risk.

Posted by Bob Rehak on 1/16/2022

1601 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.

Erosion: Sometimes Sudden

Erosion can sometimes be sudden. It’s not always a slow process of water grinding away at dirt and dissolving it, or wearing down rocks. This post will examine several examples around us and look at their implications. I intend it as a continuation of yesterday’s post about ditch maintenance.

*The Northpark Woods development (right) on the West Fork San Jacinto River (background)*

There are four main types of erosion.

Hydraulic action – When rapidly moving water churns against river banks and scours or undermines them.
Abrasion – Caused by small pebbles moving along a river bank or bed and knocking other particles loose. Think of sandpaper.
Attrition – When rocks carried by the river knock against each other. They break apart to become smaller and more rounded. This is how boulders turn into gravel.
Solution – When water dissolves certain types of rocks, for example limestone. We often see this in Florida, where sinkholes frequently develop.

Most of these processes happen slowly. But the first can be sudden. One storm. One flood. And boom. That river bank where you used to sit and quietly contemplate nature is gone.

Now You See It; Now You Don’t

Sometimes large slabs of a river bank or ditch suddenly slump into a river, almost like mini landslides. One flood expert commented on the picture above; he said “The owners of those new homes may suddenly find the ditch in their backyards.”

At other times, the size of a flood forces a river to widen. We saw this during Harvey and Imelda. The relentless pounding of flood waters carries away everything in their path. Cutbanks (the outside of a river bend) are especially vulnerable. Water slams directly into them like a firehose and washes them away. This action actually changes the course of a river over time.

Most of the time, it happens so slowly, we barely notice it. But during large floods, it’s sometimes sudden, large, and devastating to homeowners or businesses near rivers.

Three More Examples of Hydraulic Action

Example A: East End Park

*East End Park in Kingwood. In 2019, the San Jacinto East Fork removed approximately 50-100 feet of river bank during Imelda,* *including this part of the Overlook Trail.*

Example B: Balcom House and River Migration

*Note a long peninsula south of the Balcom House on the San Jacinto West Fork before Hurricane Harvey.*

*After one monster storm, the peninsula was gone. The Balcoms lost 175 feet of riverfront property.*

Example C: River Aggregate Mine on West Fork in Porter

The third example comes from the abandoned River Aggregates sand mine beyond the new development in the first picture above. It’s a spectacular example of river migration.

In this case, the San Jacinto West Fork migrated 258 feet toward the mine’s dike in 23 years. When I first photographed the dike after Harvey, the river had eaten away an average of 12.4 feet per year. At the time, the dike was only 38 feet wide, and I predicted it could soon fail. It did. Within approximately a year.

*Image taken on 9/14/2017, shortly after Hurricane Harvey. At the time, only 38 feet stood between the abandoned mine in the background that the San Jacinto west fork in the foreground.*

*Note how the pond in the foreground disappeared when the river took the last 38 feet of river bank.*

Wait a minute, you say! What happened to the pond. After the river bank collapsed, the pond drained, exposing sediment already within it. And the action of draining concentrated more sediment in it, like all the remnants of food trapped in your sink drain after you’re done washing dishes.

History of Pond

The missing, shallow pond in the foreground above used to be the settling pond for River Aggregates.

*This satellite image from 2004 shows that* *River Aggregates used the missing pond as a settling pond.*

*This is how the mine looked in 2017 after River Aggregates abandoned it.* *Note river bank is still intact.*

*This is how the abandoned mine looked in January of 2019. The river bank was gone. The pond had drained. And a steady stream of silty water from other ponds leaked into the West Fork.*

Here’s how it looks today from a helicopter.

*River Aggregates mine now leaks a steady stream of silty water into the West Fork San Jacinto.* *This is the same area as above, but from the reverse angle.*

Lessons of Life Near a River

Most people never live long enough to see massive changes such as these in rivers. In most places, river change happens on a geologic time scale. But along the Gulf Coast, hurricanes can create floods that make rivers change on a human time scale, as these examples have shown.

What can we deduce from this?

Around here, we need to give rivers room to roam. Parks, green spaces, and golf courses, often represent the highest and best use of land near a river, bayou or ditch.
Building too close to rivers, bayous and drainage ditches can be costly. Disturbing wetlands and topsoil accelerates erosion. That, in turn, can threaten everything in its path. Be prepared to maintain anything you build near a watercourse, including the watercourse itself. And be prepared to fight what ultimately becomes a losing battle.
We need greater separation between mines and the San Jacinto river. Keep mines out of the meander belt. They worsen downstream sedimentation. And as we have seen, that can contribute to sediment build ups that require public money to remove. The alternative, leaving them in place, contributes to flooding.

Here’s a current list of ditch maintenance projects in the Kingwood area.

Posted by Bob Rehak on 5/18/2020

993 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 Watchlist: Perry, Romerica, Colony Ridge and More

Here’s an update to last week’s watchlist. It includes seven Lake Houston Area developments – four from last week and three new.

Perry Homes’ Woodridge Village

On April 28, 2020, Harris County Commissioners approved the purchase of Woodridge Village from Perry Homes with two conditions: 1) that the City of Houston would defray half the cost by contributing $7mm worth of land that HCFCD needed for other flood control costs, 2) that the City would adopt new Atlas-14 rainfall statistics.

The next day, Houston Mayor Pro Tem Dave Martin discussed the deal on a Facebook live “virtual lunch” with the Lake Houston Area Chamber. At about 26:20 into the video, he said that the stipulations had already been agreed to. He said the City had already identified 11 pieces of property, 6 of which were presented to the County during its consideration of the deal in executive session the previous night. He also said the City would divert water from Taylor Gully to the Kingwood Diversion Ditch and build a barrier between Elm Grove and Woodridge, while the county built a regional detention facility.

Perry contractors went back to work the next day before Martin spoke. They continued working all week. They worked near Mace in Porter, on N2 (the large detention pond in the middle of the western border), and N3 (another detention pond on the eastern border).

A reliable source who needs to remain anonymous told me that the work was at the request of Perry’s lawyers. The source said that Perry and its contractors were simply complying with their contract.

This week marks the anniversary of the first storm (May 7th) that landed Perry in hot water. And forecasters predict an above-average hurricane season, which starts in four weeks. The lawyers may have had that on their minds, too. As they say in legal circles, “The third time is the pen.” Woodridge contributed to flooding Elm Grove twice last year, in May and September.

*Excavator working near Mace in Porter on April 29, 2020.*

Romerica’s “Orchard Seeded Ranches”

This is the 331-acre project formerly known as the Heron’s Kingwood. It wound around the Barrington and River Grove Park. Romerica is now trying to develop the same land under a different name, “Orchard Seeded Ranches.”

However, on Thursday, 4/30/2020, the Houston Planning Commission deferred approval of the developer’s General Plan.

plat of orchard seeded ranches — *General Plan of Orchard Seeded Ranches in Kingwood Texas*

The Commission then asked the developer to consult with the City Engineer; the Planning and Development Department; and Harris County Flood Control before bringing further requests back to the Commission.

That should send a strong signal to the developer that rough waters lie ahead. Any proposal will likely be debated publicly when/if the developer returns.

The development is still listed in CoH’s PlatTracker. So we will continue to watch this one.

Holley’s Kingwood Cove Golf Course Redevelopment

A review of the City of Houston’s PlatTracker Plus Map indicates that Holley has not yet applied for any permits on the golf course in Forest Cove. City of Houston confirmed that via a FOIA request (Freedom of Information Act).

Note how golf course on left is unshaded. That indicates no activity with the Planning Commission. Compare that to the purple area on the right for Romerica’s property. That indicates approval of a General Plan is still pending.

A review of the Harris County Appraisal District website indicates a limited liability company in Pittsburgh, PA, actually owns the golf course.

*Harris County Appraisal District info for property at 805 Hamblen, aka Kingwood Cove Golf Course.*

It’s not unusual for developers to use other people’s money. I shall continue to watch this. Holley says his engineer is reworking plans based on input from people surrounding the course.

Ryko Property Near Confluence of Spring Creek and West Fork

This property is in Montgomery County and the City of Houston’s Extra Territorial Jurisdiction. The Montgomery County Engineers office says the company has not yet filed any plans that have been approved. The City of Houston PlatTracker Plus Map also shows the owner has not yet filed any applications.

*US FWS Wetlands Map shows wetlands throughout the Ryko property between Spring Creek and the West Fork.*

New Caney ISD High School #3

The New Caney Independed School District plans to build a third high school south of the HCA Kingwood Medical Center and behind the car dealerships that front US59. I don’t know much more about this except that they plan to extend roads into the area that is now forest. High schools usually have large parking lots. And that means rapid drainage. It is unclear at this time whether MoCo will require detention ponds.

Northpark Woods

This high-density development along the West Fork San Jacinto River in Montgomery County is now about one-third to one-half built. Construction continues.

The Colonies in Plum Grove

North of SH99 in Plum Grove and east of the East Fork in Liberty County, lies one of the largest developments in the Houston region without detention ponds.

In January of 2017, the Houston Chronicle wrote about how La Colonia was transforming Plum Grove. They interviewed local residents who lamented the loss of forests. ABC13 ran a story about the squalid living conditions. Yet the area continues to expand.

Formally known as Colony Ridge, some locals call it “The Colonies.” Colony Ridge bills itself as a “master-planned” community with six major subdivisions: Sante Fe, Camino Real, Grand San Jacinto, Rancho San Vincente, Montebello, and Bella Vista. Together they comprise 30,478 lots on approximately 10,000 acres at present. And they’re still growing!

*The Colonies currently cover an area almost as large as Kingwood. Photo 4/21/2020.*

*Drainage empties into the East Fork San Jacinto*. *While flying over the area, I did not see one detention pond.*

*Mobil homes make up most of the housing stock.* *Note open-ditch drainage.*

Colony Ridge advertises itself as “an escape from the city, land on which to grow and build a home, no restrictions and easy credit.” Aerial photos reveal people scratching out hardscrabble lives on barren lots.

This is a blue collar neighborhood. The developer says his target market is poor Latino laborers. They see this as a step up from apartment living and a chance to own a part of the American dream.

But while flying over it, I did not see one detention pond.

As SH99, the Grand Parkway, pushes east from 59, this area will boom. Without better drainage regulations, Liberty County and Plum Grove will heap their drainage problems on those downstream.

*FEMA’s National Flood Hazard Layer Viewer shows East Fork Flood Plains relative to Colony Ridge (right).*

The good news is that Liberty County has joined with seven other counties to form a Southeast Texas Drainage District. The bad news is that Harris County is not one of the seven.

Posted by Bob Rehak on 5/3/2020

978 Days after Hurricane Harvey

Where Thousands of Trees Once Stood: The New Woodless Northpark Woods

Recently, I flew up the West Fork of the San Jacinto in a helicopter and got some pictures of the new 91-acre Northpark Woods subdivision. It’s just north of Northpark, between Sorters Road and the West Fork. Where thousands of trees once stood, I saw a massive gash in the landscape. But when reviewing my photos, something else jumped out at me – the density of this subdivision and the percent of impervious cover it will have. Both the loss of trees and the higher percentage of impervious cover increase flood risk.

Inner-City Density Comes to Suburban MoCo

I previously wrote about Northpark Woods in a post called “Living on the Edge or the Death of Caution.”

As we saw Perry Homes do with Woodridge Village, this developer clear-cut the land. Trees often don’t survive the heavy equipment used in construction. And working around them consumes time. So builders find it simpler and cheaper to let homeowners replant them. However, regrowth can take decades, especially in heavily compacted soil which stunts tree growth.

But the tiny lots in this subdivision mean buyers may never even attempt to replant trees. There’s not much room for them.

More Impervious Cover Per Lot

Developments with tiny lots have more impervious cover (roofs, driveways, streets, sidewalks) as a percentage of the lot. The higher the percentage of impervious cover, the faster runoff accumulates, and the higher flood waters peak.

Graphically, it looks like this.

*Note how much faster and higher Brays Bayou flooded as the areas around it developed. Source:* *“Houston a Year After Harvey: Where We Are and Where We Need to Be” By Jim Blackburn and Phil Bedient*.

Aerial Images Taken on 10.2.19

Photographically, it looks like this. A civil engineer told me that homes like these can have 80% impervious cover.

*Note how closely the homes are spaced. In the second row of 7 homes, you can see that garages take up almost the entire width of each home except for a front door.* *Driveways will eliminate most of the front yards* *as you can see on the developer’s web site.* *Looking NW. Sorters Road is on the right on a diagonal.*

*Compare the density and tree cover in the foreground to that of Oakhurst, beyond the tree line in the far background. Looking NE toward Oakhurst.* *Also note the huge erosion holes downstream of the weirs in the ditch. Those will soon be in homebuyers back yards.*

*Note the proximity to the San Jacinto West Fork (as well as abandoned and active sand mines), in the background. Looking west toward West Fork and the Hallett Mine.* *Here, you can also see how that ditch erosion is already threatening the road along its side.*

In Shenandoah, TX, upstream from here, the City has allowed up to 10 lots per acre with 90% impervious cover!

Shifting Flood Plains

A Denver-based developer plans to sell these as starter homes. More experienced buyers ask tougher questions. When I bought a house in Dallas at a very young age, I didn’t even know what a flood plain was. Nor did I understand how inexact a science flood plain mapping can be. Or how quickly an upstream development can increase flooding downstream.

Within three years, I went from being two feet above the hundred year flood plain to ten feet below it.

Approximate outlines of development in white over MoCo floodplain map. Virtually half of the Northpark Woods subdivision is in floodplain (500year=brown, 100-year=aqua). New upstream developments have decreased the time of accumulation and increased flood peaks. See first graph above. Caution: the data behind these flood maps is from the 1980s and being updated.

The detention ponds on this site occupy the 100-year floodplain (aqua). About half the homes will be in the 500-year floodplain (brown). But keep in mind, the data on which this flood map is based has not been updated since the 1980s. So the real floodplains most likely cover far more area than shown here. Don’t be fooled by the 2014 date. The background image was updated then, not the height of the floods.

As long as less knowledgable people keep buying such homes in locations like these, developers will keep throwing them up.

Ironically, about three miles downstream, Harris County Flood Control is buying out another high density development near the West Fork. And Tammy Gunnels, only a quarter miles downstream – and in the 500-year flood plain – has now flooded 12 times in the last ten years.

Buyer Beware

Among the many other dangers of building in this location: river migration. The San Jacinto West Fork is migrating toward these homes at the rate of about 20 feet per year. When the river captures the abandoned sand pits next to these homes, it could migrate much faster.

The legal principle of “Caveat emptor” (Buyer beware) means that the buyer alone is responsible for checking the quality and suitability of goods before a purchase is made. Caveat emptor still applies when buying a house.

Most young people would not think to question when flood maps were last updated, especially if they see a date of 2014.

The data behind the flood map above is currently being updated as part of the San Jacinto River Basin Study by Harris County Flood Control, Montgomery County, SJRA and City of Houston. As of this writing, hydrologic and hydraulic models have been developed. Consultants are now calibrating those to known high water marks, such as those in this 2018 USGS study.

The USGS study shows that Hurricane Harvey at the Highway 99 gage (closest upstream gage) had an annual exceedance probability (AEP) of 2.4.

That means USGS classifies Harvey as a 42-year storm.

It could take years for that San Jacinto River Basin study to go through required public review and approval processes. Expect developers and other landowners to fight new maps every step of the way. More realistic flood maps will mean higher development costs for property that suddenly finds itself in a floodplain. And some properties could end up in floodways and be totally undevelopable. In the meantime, caveat emptor.

Posted by Bob Rehak on 10.22.2019

784 Days since Hurricane Harvey

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.

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