Tag Archive for: FM1485

Colony Ridge Buying Up Floodplain Land in Huffman

Colony Ridge Land, LLC, developer of the world’s largest trailer park in Liberty County, is buying up Harris County property in the floodplain of the East Fork San Jacinto. Since the property in the Cypress Point subdivision was originally platted, flood maps changed in 2001 and are in the process of changing again. Most of the properties face serious flood risk that the current flood maps may not communicate.

Land Remains Uncleared

Development has not yet started. The land is still heavily wooded…so much so, in fact, that dirt roads developed in the 1980s have become overtaken by trees and undergrowth. They are barely passable according to one person I talked to.

Colony Ridge has acquired at least 19 (but not all) properties within red area.
What the partially developed area looked like in 1988. Note unpaved roads nearest river.

Back in the late 1980s, the original developer cleared space for roads and platted the land going down to the East Fork. But today, paved roads stop about a quarter mile short of the river. From the air, those old dirt roads look like a slight indentation in the forest canopy.

Looking NE from over the utility corridor that forms the southern limit of the area. East Fork on right flows toward camera.
Looking NE from farther north. Old roadway appears as a crease in the jungle.
Still looking NE. Note how pavement on Birchwood Drive stops short of entering area.
Reverse angle looking S toward Lake Houston visible as blue streak below horizon in upper left. Lake Houston Park on right.

The Big Question

Why did the original developers stop short of paving roads all the way to the river? The answer likely has something to do with floodplains. Note in the image below how several of the lots border or lay within the floodway. Many more lay within the 100- and 500-year floodplains.

How Bad Could Flooding Be?

But those floodplain maps are outdated and can mislead. High-water marks established by HCFCD and contour maps by the U.S. Geological Survey suggest this property has flooded seriously at least 8 times in the last 20 years.

Elevation profile from USGS National Map

From the East Fork to the end of Oaknoll Drive, the elevation rises from approximately 42.5 feet to 67 feet. The 24.5-foot difference might sound like a lot. But consider this.

In 1994, the flood of record for the East Fork in this area (before Harvey), crested at 76.2 feet. That would have put the highest property near Oaknoll under 9 feet of water. The lowest property near the river would have been under 33.7 feet of water.

Then came Harvey. At the nearest gage, the East Fork crested at 81.2 feet.

That would have put the highest and lowest properties under 14.2 feet and 38.7 feet of water respectively.

All figures were computed using the elevation profile function in the USGS National Map, and cross referencing the results with the Harris County Flood Warning System gage at FM1485.

Even though most of the acquired properties are shown in the 500-year flood plain, most of them have been under water eight times in the 20 years since 1994.

Approximate high water marks from HarrisCountyFWS.org gage at FM1485 and East Fork.

In fact, most of the undeveloped lots likely flooded in an unnamed and already forgotten flood in April of this year.

HarrisCountyFWS.org.

Official Floodplains Expanding

Floodplains change with better understanding of the climate, upstream development, and better measurement technologies, such as LIDAR. Our current flood maps were developed after Tropical Storm Allison in 2001. But we’ve gotten a lot smarter about flood mapping since then.

That’s why Harris County Flood Control District and FEMA are updating flood maps for this area. The floodplains you see above will likely expand by 50% to 100% according to preliminary guidance from Harris County Flood Control. FEMA is in the process of certifying revised maps and should release them later this year or early next for public comment.

From MAAPnext.org.

Are Readings from FM1485 Analogous to Cypress Point?

Give or take few feet, the flood depths cited above are probably in the ballpark. Even if the high-water marks at Cypress Point are a few feet lower, they still represent serious flooding.

HarrisCountyFEMT.org shows that the width of the floodplain at FM1485 and Cypress Point, lower left, does not vary significantly.

One of the region’s leading hydrologists who has studied this area extensively felt the flood heights at FM1485 would translate well to Cypress Point where Colony Ridge is acquiring property. Colony Ridge has purchased at least 19 properties in the affected area. The map below shows where they are.

Note how virtually all purchases happened after Imelda, which would have put even higher properties under almost six feet of water.

Another property valuation report shows how the land value decreased 73% after Imelda in 2019. Colony Ridge purchased most of the properties in 2020. Bargain hunting?

Homes on Stilts Likely Unaffordable for Colony Ridge Target Market

It’s not clear what Colony Ridge plans to build on this property. However, the company has a history of selling land to Hispanic immigrants, then letting them clear their own lots and bring in trailer homes.

Many may not have a firm grasp of English. Few likely understand flood risk, especially the nuances of flood maps in flux. And Colony Ridge typically “owner finances,” meaning buyers don’t go through banks which would require flood studies and flood insurance before making a mortgage loan.

Alleged abuses are so common that whole websites have been set up to chronicle them.

Under today’s guidelines for developing land in floodplains, especially this deep in floodplains, homebuilders would likely have to elevate homes on stilts. And elevating homes 35 feet high would likely make them cost prohibitive for most of Colony Ridge’s primary target market.

Watch this one closely to make sure that no rules get broken.

Posted by Bob Rehak on 8/4/23

2166 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.

East Fork Flooding Migrates Downstream

Two days ago, I wrote about San Jacinto East Fork Flooding at FM2090 in Plum Grove. Yesterday, floodwaters were peaking downstream at FM1485/SH99. No homes were threatened that I saw, but at least one vehicle stalled and was abandoned.

Pictures Taken on 4/10/23 Just After Peak

See the pictures below that I took Monday afternoon when the river was at 63 feet.

Looking west along SH99 at the San Jacinto East Fork where FM1485 parallels the Grand Parkway.

Note the difference in the width of the spans in these bridges. The newer bridge is at least 5X wider. Because water flows right to left, this creates a bottleneck that causes the roads in this area to go underwater frequently. TxDoT probably needs to widen the 1485 bridge or elevate the roadway or both.

Looking east. Upstream (left) of the 1485 bridge, the East Fork remained placid. But downstream, you can actually see the currents in the rushing water.
Looking east from over eastbound FM1485 as vehicles attempted to plough through water. Note the black car stalled at the side of the road farther up. That one didn’t make it.
Looking west at same location. Despite the dangers, vehicles persisted through the water. There was no room for them to turn around.

All this was caused by rain falling 20 or more miles upstream last week.

According to the stream elevation table below, the floodwaters at FM1485 have since receded.

From Harris County Flood Warning System.

The floodwaters are moving even farther downstream toward the headwaters of Lake Houston. According to the Harris County Flood Warning System, the lake elevation is still about a half to a full foot above the spillway. According to USGS, the top of the spillway is at 42.4 feet above sea level.

From Harris County Flood Warning System.

As of this writing (noon on 4/11/23), SJRA has scaled back its releases from Lake Conroe to about 1000 cubic feet per second (CFS).

Caution to Swimmers and Waders

Swimming or wading in floodwater can endanger your life. A cubic foot of freshwater weighs about 62 pounds. Rapidly moving water that rises above knee level has enough force to easily knock adults over and sweep them downstream.

The East Fork at FM1485 is still moving at more than 4000 CFS!

USGS

So swimmers and waders beware. This morning a reader wrote me about a woman and her daughter who were killed in the East Fork after Harvey. The woman could not battle the current. Her daughter tried to save her and both died.

Understand also that floodwaters can easily scour the riverbed to create drop-offs in unexpected places. Even if you could safely wade in areas before the flood, after the flood, you could easily step into holes over your head.

If you find yourself swept up in a strong current, don’t try to swim against it. Swim perpendicular to it or with it to reach shore.

Posted by Bob Rehak on 4/11/2023

2051 Days since Hurricane Harvey

Grand Parkway Extension is Getting There

TxDOT’s Grand Parkway extension (a.k.a. State Highway 99) is rapidly moving east and south toward I-10. As it arcs around the northeast quadrant of the Houston Metro Area, it will open up vast new areas to development. Below is a map showing several already under development.

New Developments Already Under Way

New developments that will take advantage of mobility improvements brought about by the Grand Parkway extension. From City of Houston Plat Tracker. Gray area is City’s Extra-Territorial Jurisdiction (ETJ).

East Fork Crossing: Tale of Two Bridges

Yesterday, as I was photographing different areas near Huffman and New Caney near the San Jacinto East Fork, I captured these shots of the Grand Parkway extension and FM1485. The Grand Parkway is still under construction in this area, but it’s rapidly getting there.

SH99 and FM 1485, looking northeast toward Colony Ridge and Liberty County.
SH 99 and FM 1485 looking north with San Jacinto East Fork running through middle of frame from top to bottom.
SH 99 and FM 1485 Looking east over San Jacinto East Fork

In March, this Grand Parkway in this area was nothing but dirt. By June, they were clearing land down to the Luce Bayou InterBasin Transfer Canal. Now it’s concrete as far as the eye can see. At least from the East Fork.

I’ve taken shots of this area before and am fascinated by the difference in the spans of the bridges. Part of what you’re seeing is the difference between standards for Farm-to-Market Roads and State Highways. But you’re also looking at the consequence of an increase in expected rainfall rates, more upstream development, and learning from experience. FM1485 frequently goes under water nowadays.

Detention Pond under Bridge: Permanent?

One of the curious things I noticed yesterday was a large detention or sediment retention pond under the bridge. TxDOT has rerouted the East Fork around it as you can see in the first and second photos. I wonder if they will keep it as a large detention pond under the freeway when they complete construction. Or whether they will return the river to its normal course and plant trees between the two roads as you see in the distance.

Stay Away During Construction

Traffic detours through this area are a nightmare. Stay away if you can. It took me an hour to get from here to Kingwood yesterday via 1485, 494 and US59 at 2:30 pm. The distance: only 7 miles as the crow flies.

Posted by Bob Rehak on 12/4/2021

1558 Days since Hurricane Harvey and 776 since Imelda

FM1485: What’s Wrong With This Picture?

I took this picture on May 26, 2021. It shows TxDOT construction of the new State Highway 99 (Grand Parkway) next to FM1485 in New Caney. The picture looks northeast toward Colony Ridge in Liberty County. The East Fork of the San Jacinto River flows under both bridges toward Lake Houston on the right.

Looking east toward Colony Ridge across FM1485 and the East Fork. Water flows left to right.

Note the huge backup of water trying to get under the FM1485 bridge. Also note how much taller and wider the new bridge is compared to the old one.

How Much Rainfall Caused This?

Here is rainfall for the month of May as measured by the Harris County Flood Control District Gage at this location.

The Harris County Flood Warning System shows that the largest rainfall for the month was 2.28 inches TWO days before the photo. But the ground was clearly saturated from steady, moderate rains the week before.

The gage upstream at FM2090 shows slightly more rain. It reported 14 inches for the month instead of 11, but it received exactly 2.28 inches on the same day this gage did. While 2+ inches in a day is substantial, few in this part of the world would consider it excessive – especially since it was spread out over 5 hours.

Likewise, according to Atlas-14 standards, the rain that fell in the week before would qualify as a 1- to 2-year rain – notable, but not historic.

Note the 7-day rainfall totals in columns 1 and 2.

Submerged 41 Times in 32 years

And after consulting Harris County Flood Control District records, I learned that FM1485 has gone under water 41 times since 1990 – an average of 1.32 times per year.

The East Fork came out of its banks and flooded this area twice in the week before the picture was taken.

Rainfall data, road flooding frequency and the photo all suggest that a 1- to 2-year rain is enough to flood FM1485.

What Should a Roadway over a Major River Withstand?

Yet the TxDOT standard suggests that such minor arterials and bridges over a major river crossing be built to withstand 25- to 50-year floods. Oops!

Obviously TxDOT built a much higher road and a much wider, taller bridge for its new highway. The new one is approximately five times wider than the old one. Construction standards for major highways could account for that. But so could TxDOT’s experience with FM1485.

So What’s Going on Here?

Why did TxDOT make the new bridge so much wider and taller?

  • Did TxDOT just get the engineering wrong on the old bridge?
  • Did bridge standards change over time?
  • Do state highways have higher standards than farm-to-market roads?
  • Did Atlas-14 increase the risk?
  • Did upstream development, such as Colony Ridge, alter the hydraulics of the watershed when the developer paved over wetlands and deforested thousands of acres while providing little detention-pond capacity?
  • Did the mischaracterization of soil types in Colony Ridge lead to more runoff than anticipated?
  • All of the above?
  • Some of the above?

Jeff Lindner, Harris County’s meteorologist, cautions that, “Water surface elevations depend on many variables…rainfall patterns, intensity, soil conditions, water level in the river when the rain started, ect. It is usually difficult to compare events as no two are exactly alike. You really need a hydrological analysis of the location to determine the amount of run-off from that site into the river per an amount of rainfall.”

Good luck with that! More than six months after the Liberty County Attorney launched an investigation into Colony Ridge drainage reports, we still are waiting for answers.

Posted by Bob Rehak on 7/15/2021

1415 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.

East Fork Rose 11 Feet Today; Almost Out of Banks at FM1485

The East Fork of the San Jacinto at FM1485 received almost 10 inches of rain today, including almost two inches in one hour late this afternoon.

Just upstream at 2090, the East Fork also received more than 10 inches in heavy bursts throughout the day.

As a consequence, the East Fork has risen 11 feet in the last 20 hours. It currently stands at about 57 feet. Flooding becomes likely at 60 feet.

Therefore, the river has three more feet to rise before coming out of its banks at FM1485.

Stay alert. For the most up to date information, consult:

  • HarrisCountyFWS.org
  • Click on the gage nearest you.
  • Select “For more information”
  • Click on the Rainfall and/or Stream Elevation tabs to see graphic representations like those above.

Better yet, establish an account and sign up for automated alerts. You can customize your preferences or accept defaults for as many gages as you wish.

The ground is already saturated. So any additional rainfall will result in rapid runoff So good luck to East Fork residents tonight and tomorrow.

Jeff Lindner, Harris County Meteorologist says “Additional rainfall amounts of 2-4 inches with isolated amounts up to 6 inches will be possible in this area with totals west of I-45 generally less than 2 inches.”

Posted by Bob Rehak on 9/18/2019 at 6pm

750 Days since Hurricane Harvey