upstream detention Archives

Is Downstream Flood Mitigation Keeping Pace with Upstream Development?

5/14/25 – This morning, I gave a presentation that compared the pace of downstream flood mitigation with the pace of upstream development. Are we gaining or losing ground in the Lake Houston Area?

Presentation Connects Many Dots

Answering that question requires connecting many dots. Here are the slides from the presentation with my narrative.

*To download a PDF of the presentation, click here.*

Offsetting Forces

As new upstream development adds impervious cover (roads and roofs) that can increase and accelerate runoff, building flood peaks higher and faster. And that can erode the safety of downstream residents. Managing flood risk becomes a struggle between competing forces.

MoCo One of Fastest Growing Counties in Country

The Lake Houston Area lies downstream from one of the fastest growing counties in the country. Montgomery County (MoCo) grew 68% in the last 15 years and 4.8% in 12 months recently. MoCo is currently the seventh fastest growing county in the entire country.

Ryko Exemplifies Danger of Upstream Development

Let’s look at a proposed MoCo development in the headwaters of Lake Houston. A company named Ryko bought 5,500 acres about a quarter mile west of Kingwood. It’s in the southern part of a triangle formed by Spring Creek, the San Jacinto West Fork and the Grand Parkway.

*US59 Bridge in foreground by the confluence of the Sand Jacinto West Fork and Spring Creek*.

“Like Aiming a Firehose At Kingwood”

Ryko, which is a Syrian-owned company, is reportedly working with Wan Bridge, a Chinese company, to develop 7,000 homes on the property. One of the leading hydrologists in the area told me that developing this property would be “like aiming a firehose at Kingwood.”

Many “Guardrails” Being Removed

Government has established many guardrails over time to protect people from insufficiently mitigated upstream development. But many of the guardrails are being removed. Or people are trying to remove them.

In this case:

A change to the state property code in 2023 gave developers the right to opt out of a city’s extra territorial jurisdiction (ETJ). ETJs lay the groundwork for future annexation by ensuring new infrastructure meets the standards of areas that might annex them someday. But if developments are not in an ETJ, they could change plats without approval.
Two bills pending in the legislature, HB23 and its companion SB2354, would essentially let developers “self-permit” by hiring engineering firms that replace government oversight.
The Endangered Species Act (ESA) constrains development in areas inhabited by threatened or endangered species. But Executive Order 14192 could change that. The US Fish and Wildlife Service has proposed a change under the order that means Ryko would no longer have to work around endangered species on its property.
An ex-Senior VP of Ryko for 21 years is now chair of the Houston Planning Commission. She still reportedly represents the company as an independent consultant,
The Montgomery County Drainage Criteria Manual hasn’t had a serious update for 40 years. The County still allows controversial practices, such as hydrologic timing surveys, to “prove” that upstream developments have no adverse impact on downstream residents.

Let’s take a closer look at the Ryko property with these issues in mind.

Upstream Development Almost Entirely in Floodplains

With that as a backdrop, what’s going on with the Ryko land? The map in the background for this next slide comes from Ryko’s Drainage Impact Analysis. It shows that their property (outlined in red) lies at the confluence of four major streams. All that blue represents floodplains and floodways.

*Property outline and stream names enhanced for readability.*

How Bad Is Ryko’s Flood Risk?

FEMA’s base-flood-elevation viewer shows that at the southern end of Ryko’s property, any homes would be under 25 feet of water in a 500-year flood (18.7 feet in a 100-year flood). Even at the higher elevations farther north, homes would be under 7 feet of water in a major flood.

Frequent Bald Eagle Sightings

Homeowners father north report frequent sightings of bald eagles. They believe the eagles live on Ryko’s property which is currently wilderness. One resident sent me a video of two eagles that landed in a tree right outside her living room window.

How Developers Document “No Adverse Impact”

The Texas Water Code contains a rule that states upstream development can have “No Adverse Impact” on downstream neighbors. To prove no adverse impact, engineers compare estimated pre- and post-development runoff.

If post-development estimates are less than or equal to pre-development, they satisfy the requirement.

Estimates Based on Hydrologic Timing Not Always Accurate

But how accurate are those estimates? Montgomery County’s antiquated drainage criteria manual still lets engineers use hydrologic timing surveys, a practice now prohibited by the City of Houston and Harris County for several reasons.

Timing studies let developers avoid building detention basins if they can show that their development’s stormwater “beats the peak” of a flood. The theory: they aren’t adding to the peak.

Not building detention basins saves developers money and adds to the number of salable lots. But “beat the peak” studies have serious limitations and can often mislead.

They assume, for instance, a uniform storm across an entire watershed. But that rarely happens. Imagine the case of a storm like Harvey, which approaches from the south as developers to the north rush to get their water to the river. God help the people caught in the middle.

Timing surveys, in the case of Montgomery County, are also based on decades old data that ignores the cumulative impacts of other developments over time.

How Avoiding Detention Can Add to Flood Peaks

What often happens in reality is that you get higher peaks than if you had built detention. This graph shows three lines. The two at the bottom show typical pre- and post-development runoff rates where/when hydrologic timing studies are prohibited.

*Not building detention often leads to earlier, higher peaks*.

The height difference could be the difference between flooding or not flooding.

MoCo Still Doesn’t Require More Reliable Method

In short, building stormwater detention is a sure thing. Hydrologic timing is not.

Banning hydrologic timing studies would force developers to design systems that TRULY detain and slow runoff. But Montgomery County still permits timing studies. The County’s new Drainage Criteria Manual that prohibits them has been sitting on the shelf for more than a year.

Downstream Mitigation Slowing

Now, let’s look at what downstream residents are doing to offset the impacts of upstream development.

Compared to the period after Harvey, that activity has slowed. The Lake Houston Area Task Force identified three crucial needs to reduce flood risk.

Dredging to increase throughput
More floodgates on Lake Houston to speed up output
Upstream detention to reduce input.

Dredging is Highlight to Date…

Dredging continues. We’ve spent approximately $200 million to date and that total is still increasing.

*Images shot current West Fork dredging plan, location of dredge by FM1960, and spoils placement area by Luce Bayou.*

…But More Sediment Keeps Coming

After the Army Corps finished its emergency West Fork Dredging Project, they recommended regular maintenance dredging to ensure our rivers had sufficient conveyance and our drainage ditches were not blocked. State Representative Charles Cunningham authored HB1532 to create a dredging district for the Lake Houston Area.

HB1532 passed overwhelmingly in the House and is now waiting to be heard by Senator Paul Bettencourt’s Local Government committee in the Senate.

But this legislative session ends in two weeks. Any bill not out of committee by this Friday is effectively dead. And Bettencourt has not yet scheduled Cunningham’s bill for a hearing.

Construction on More Floodgates Not Likely Before 2027

The additional floodgates on Lake Houston have been delayed repeatedly for various reasons. Simultaneously, the Coastal Water Authority (CWA) is looking at the costs of repairing the dam and replacing it altogether. The 70+ year old dam is near the end of its useful life.

CWA board member Dan Huberty stated that engineering for additional gates should be complete by 2027. At that time, the project will go out for bids.

The CWA won’t receive preliminary reports on dam repairs and replacement until at least July of this year.

No Progress on Upstream Detention, None Likely Anytime Soon

Meanwhile, virtually nothing has happened yet in terms of upstream detention. The San Jacinto River Authority identified 16 areas for upstream detention basins/lakes in its River Basin Master Drainage Study.

SJRA has no construction funds. So many of the projects were incorporated into the state flood plan. But the state’s Flood Infrastructure Fund does not have a committed revenue stream.

The Texas Water Development Board has about a billion dollars currently available to build $54 billion worth of requests in the flood plan.

So keep the pressure on elected representatives who can protect your family.

Posted by Bob Rehak on 5/14/25

2815 Days since Hurricane Harvey

Bridge over Tracks, Upstream Detention on Friday’s Commissioners Court Agenda

Two Kingwood-related items are on Harris County Commissioner’s Court agenda for this Friday.

#60 Recommendation to execute a Partnership Agreement with TXDoT for preliminary engineering and environmental review for a railroad grade separation on Hamblen Road, from Loop 494 to Laurel Springs Lane.

#83 Authorization to negotiate an interlocal agreement for a partnership project with the SJRA, Humble, and five utility districts for a feasibility study and conceptual design on the Spring Creek Watershed Flood Control Reservoirs.

Bridge over UP Tracks

The first item relates to the development of Precinct 4’s new Edgewater Park at 59 and the West Fork. Hamblen Road will be re-routed during park construction so that it connects with the first bridge over US59 north of the West Fork and Sorters-McClellan Road.

This would improve traffic flow and expand the development area of the 90-acre park that will serve as a key anchor park along the Spring Creek Greenway trail.
The current two-lane asphalt segment of Hamblen Road runs across the Union Pacific Railroad track through the middle of the proposed park. Plans include rerouting the new segment diagonally from Loop 494 at Sorters-McClellan Road to Laurel Springs Lane and upgrading it to a four-lane concrete with a bridge over the railroad track. The previous Hamblen Road segment could then be repurposed to serve park visitors. If approved, construction will not affect the park’s cypress ponds.

*Tentative plans for a new Edgewater Park at Hamblen Road and Loop 494. The proposed bridge across the railroad would be part of the diagonal segment.*

The bridge would also provide an evacuation route from Kingwood in the event of a railroad accident. UP plans to increase the length of its trains making a bridge more important than ever. In the event of a derailment, the longer trains (without the bridge) could block all Kingwood exits to US59.

Also, the current intersection is one of the most dangerous in Kingwood. Danny Sullivan, of Sullivan’s Automotive, says he tows vehicles almost daily from this stretch of road. There are a number of blind turns with people trying to cut across multiple lanes as traffic zooms north off the San Jacinto bridge.

Spring Creek Reservoirs: Feasibility Study, Conceptual Design

The second item arose out of the San Jacinto River Basin Master Drainage Study and a Spring Creek Siting Study conducted in parallel. This current project would study the feasibility of alternative locations and provide conceptual designs for one or more reservoirs.

Additional upstream detention is one of the three main legs of the Lake Houston Areas flood-reduction strategy. Upstream detention would reduce the inbound flow; dredging is restoring conveyance of the West Fork; and additional gates on the Lake Houston Dam will help eliminate backups.

*Peak flows from various tributaries during Hurricane Harvey. Source: SJRA.*

During Harvey, Spring Creek provided one third of the flow coming down the West Fork between Humble and Kingwood. To put that in perspective, that was as much as the peak release from Lake Conroe. Retaining even a portion of Spring Creek’s floodwater upstream would benefit people in Precinct 3 and Precinct 4 all across northern Harris County.

So even though this would be far upstream and not in our area, it still has the potential to reduce flooding significantly in the Lake Houston Area. And that’s very good news.

Thanks to Precinct 4 Commissioner Jack Cagle, Harris County Flood Control and their partners for pushing this project forward.

Posted by Bob Rehak on 2/24/2021

1275 Days since Hurricane Harvey

HCFCD Closes on First Upstream Detention Property

In 2018, Lake Houston area leaders identified a three-pronged strategy to help mitigate flooding. They dubbed it the “Plea for DDG.” Additional dredging, detention, and gates. Since then, dredging and gates have garnered the most media attention. Yesterday, however, we received some good news regarding additional upstream detention.

HCFCD Buys First Part of Raveneaux Club

The Harris County Flood Control District (HCFCD) closed on the purchase of the Raveneaux Country Club on January 30, 2020. The final purchase price for 27.63 acres of land was $11,496,427.20 which is also the current appraised value for the property.

*Cypress Creek runs through the Raveneaux Club before joining Spring Creek and the West Fork of the San Jacinto upstream from Lake Houston.*

The final deal includes a leaseback allowing the Country Club to continue operating for up to one year.

The Flood Control District will begin discussions with the Cypress Forest Public Utility District in February regarding an agreement to acquire the remaining 206 acres that primarily make up the golf course. HCFCD intends to use the land for a future flood risk reduction project in the Cypress Creek watershed.

Benefit to Cypress Creek AND Lake Houston Area

That project could help the Champion Forest area where hundreds of homes flooded during Harvey and other recent storms. It could also help the Lake Houston Area. By reducing and delaying floodwaters coming down Cypress and Spring Creeks, it could help offset releases from the Lake Conroe Dam.

Funding for Acquisition

Funding for the Raveneaux acquisition will come from the 2018 HCFCD Bond. See Project F-20 Cypress Creek Right-of-Way Acquisition and Floodplain Preservation.

Community Input Sessions Planned

The Flood Control District realizes that community interest in this matter is very high. At this time, project specifics have not been determined. The Flood Control District will have community engagement meetings to solicit input and ideas about the future project.

Some feel the loss of the Club could adversely impact surrounding home values. However, the Club had reportedly been losing close to a million dollars per year for several years and was no longer financially viable.

In a special web page devoted to the acquisition, HCFCD says it cannot predict how property values will change as a result of this proposed project. However, HCFCD “knows that properties with a lower risk of flooding have a higher value than properties with a high risk of flooding.”

First Part of a Larger Solution

It is unlikely that HCFCD will find one undeveloped tract of land large enough to reduce flooding in the Lake Houston Area by itself. Acquiring a combination of smaller tracts such as Raveneaux will likely be necessary. Yesterday, HCFCD took the first step toward a larger solution.

For more details as they become available, see: https://www.hcfcd.org/Find-Your-Watershed/Cypress-Creek/Raveneaux-Acquisition-Information

Posted by Bob Rehak on January 31, 2020

885 Days since Hurricane Harvey

Big Stories to Watch in 2020

As we enter 2020, keep your eyes on these stories.

Elm Grove Lawsuits and Mitigation

In 2019, Elm Grove flooded twice with runoff from the Perry Homes/Woodridge Village development in Montgomery County. Hundreds of homeowners sued Perry Homes’ subsidiaries (PSWA and Figure Four Partners) and their contractors.

On 12/17/19, attorney’s for the plaintiffs filed a fourth amended petition. Since the original filing, plaintiffs have named Double Oak Construction and Texasite LLC as additional defendants.

The judge set a jury trial date for July 13, 2020. To date, Perry Homes has done nothing to reduce the threat of flooding from their job site.

*The 268-acres clear-cut acres that contributed to Elm Grove Flooding.*

That brings us to the subject of mitigation.

What can be done to restore the safety of residents?

Perry Homes has demonstrated no interest in reducing the threat to downstream flood victims.

Protecting homeowners will require massive intervention from an outside source. But who? And how?

Harris County Bond Fund Mitigation Projects

In 2019, Harris County Flood Control began work on 146 of 239 of the projects identified in their $2.5 billion flood bond.

Many of those projects required studies and partners. Three affecting the Lake Houston Area are:

*Many projects could actually enter the construction phase next year.*

Recommendations from each study should come out in 2020. Then many more projects will get underway.

Upstream Development

In 2019, we saw what upstream development did to homes in Elm Grove and North Kingwood Forest bordering Taylor Gully.

I recently learned of two new developments in the Ben’s Branch watershed.

A developer intends to build 18 acres of apartments where the woods adjacent to the new St. Martha Church now stand.
Another developer intends to build hundreds of homes on tiny lots on an 80-acre site just north of St. Martha’s.

These two projects represent dozens of others gobbling up farm and forest land in southeast Montgomery County.

*This drainage ditch feeds into Ben’s Branch at Northpark Drive. The 18 acres of trees on the other side of the ditch could soon become apartments.*

Businesses such as the St. Martha School and Kids in Action already flooded twice this year. So did dozens of homes along Ben’s Branch.

Additional upstream development has the potential to make flooding even worse. This is like death by a thousand cuts. Residents just don’t have the time or energy to monitor each development to ensure that owners follow rules and regulations for wetlands, floodplains, drainage, etc. Neither evidently does Montgomery County. Which brings us to…

Montgomery County Standards and Enforcement

Montgomery County competes for development by touting its lack of regulations. That’s a huge problem for downstream residents.

Montgomery County still bases flood maps on data from the 1980s.
Large parts of the county remain unmapped for flood hazards.
The County last updated its Drainage Criteria Manual in 1989.
Developers ignore many provisions within it.
County Commissioners voted to leave loopholes open that allow developers to avoid building detention ponds.
The County even paid an engineering company to investigate itself for its role in the Elm Grove Disaster.

You get the idea. If you thought some benign government entity watched over new developments to protect downstream residents, think again. Below you can see the 80-acre site I mentioned above.

*Source: USGS National Wetlands Inventory.*

Note how it was covered in wetlands. Developers did not ask permission from the Corps to remove them. They just decided on their own that they didn’t need to ask.

Below, you can see how virtually half the site is in a flood zone or floodway.

*Source: FEMA’s national flood hazard layer viewer.* *Brown = 500 year flood plain, aqua = 100 year, cross-hatched equals floodway*.

Here’s how it looks in Google Earth. Developers have already cleared the site.

Developers intend to build high-density homes in the floodplains. They will also build their detention pond in the floodway. Those hazard areas will likely expand when and if the County incorporates new Atlas-14 data into their flood maps.

*Layout for Brooklyn Trails development in Montgomery County*

None of this seems to bother the leadership of Montgomery County. And that’s a bigger problem than any one development.

In 2020, expect more focus on the decision-making process and decision makers who have created a permissive culture of indifference to flooding problems.

Sand Mines

Sand mines operate so closely to the San Jacinto that their walls frequently break and pour polluted process water into the drinking water for 2 million people. If they get caught, they pay a small fine and continue operating with impunity.

Left: Liberty Materials Mine in Conroe that undercut five pipelines carrying highly volatile liquids. Center: Triple PG mine in Porter where erosion during Imelda exposed one natural gas line and threatens 5 more HVL pipelines. Right: Another Liberty Materials mine that allegedly dumped 56 million gallons of white goop into the West Fork.

Upstream Detention

During Harvey, the release of 80,000 cubic feet per second from Lake Conroe added to downstream flooding. The goal: to find enough upstream detention capacity to help offset future releases. The San Jacinto River Basin Study will examine that possibility. It’s unlikely that one reservoir will provide enough capacity. However, multiple smaller reservoirs may.

The study partners will release their results in the second half of 2020. Land acquisition and construction could take several additional years.

Dredging

Dredging is another essential element of flood mitigation on the West Fork of the San Jacinto. Sand buildup near the mouth of the river has created a giant sediment dam. The Army Corps removed three feet in a dredging effort that ended on Labor Day. But much remains.

Luckily, State Representative Dan Huberty sponsored legislation that allocated another $30 million. The Harris County Flood Bond allocated $10 million. The City of Houston allocated $6 million. Plus two more grant requests are still pending that could increase the total even more. And a disposal site for the material has already been permitted.

*Mouth Bar of the West Fork. Photo taken 12/3/2019.*

Last week, Harris County commissioners voted to proceed with additional dredging. Project managers are studying the most cost effective ways to proceed. We should see more dredging soon.

This money could also be used on the growing mouth bar of the East Fork.

State Highway 99 Extension

The extension of the Grand Parkway (State Highway 99) east and south to I-10 will open up vast new expanses of forest and farmland to high density development. The biggest threat will be to the East Fork watershed as construction moves through southeast Montgomery County and the northeast tip of Harris County into Liberty County.

*Eastward clearing for SH99 has reached Caney Creek near Lake Houston Park.*

Those are my predictions for the biggest stories of 2020. There’s a lot of good news in the forecast and much to remain vigilant about. Life seems to be a constant struggle between those who would increase and decrease our margin of safety when it comes to flooding.

Posted on 12/21/2019 by Bob Rehak

844 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.

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