The San Jacinto West Fork has become totally blocked by sediment at the Hallett Mine in Porter and rerouted itself through the giant sand mine.
The old river channel has been sealed off by sediment. And the river now enters and exits one of the mine’s largest pits through large breaches in what used to be dikes. See below.
White oval shows location of blockage. Blue line shows old route of river. Red lines show detours through sand pit.
More than Normal Erosion
Rivers always move during floods through erosion. But this represents a far larger than normal amount of movement through a process called pit capture.
The river now runs through the Hallett pit instead of following its normal curving channel.
See photos below.
The loss of the dikes is likely the result of the SJRA releasing 71,000 cubic feet per second from Lake Conroe during the peak of the recent flood. That was the second largest release in the history of the SJRA.
Pictures taken just before the peak of the flood show the river already overtopping the pit’s dike. Dikes like walls that separate the river from the mine’s pits. They keep industrial wastewater out of your drinking water.
Weak Sand Mining Regulations Brought This On
Two other contributing factors are the depth of the pit compared to the river and the width of the dike.
The deeper the pit (compared to the river), the less stable the dike.
The narrower the dike, the weaker it is.
Until recently, Texas was one of the few states (if not the only one) that had no minimum setbacks of mines from rivers. Bill McCabe of the Lake Houston Area Flood Prevention Initiative was instrumental in lobbying for greater setbacks. The TCEQ adopted them in 2021, but this pit predated the new regulation. And the TCEQ did not enforce the regulation in this case.
In fact, this pit was open on its southern end since January. That breach was already expanding before the recent flood.
Pictures Taken Before and After Flood Show Pit Capture
Pictures taken during and after the flood show the impact.
Hallett Mine San Jacinto West Fork on May 3, near peak of recent flood.Same area photographed on May 11, 2024. Break in dike is circled in red.
Following the river around to the right, you can see how much sand the river laid down. This likely happened when the volume of water moving through the channel decreased as the velocity decreased, allowing suspended sediment to drop out of suspension.
The river which flows right to left, used to flow toward the bottom left. But now it flows into the pit (upper left).Closer shot showing the river being diverted into piton the left.
This video shows the height of the sand deposited in the river bed when the river started flowing to the pit instead of following its normal channel.
Video courtesy of a fisherman, Jody Binnion. Listen to his narration.This shot also gives you some idea of the height of the sand now blocking the river.Farther upriver but looking downriver, you can see how the river has been diverted. Note how narrow the dike is/was as it approaches the point of failure.Note the ripples on the water flowing into the pit.At the far southern end of the pond, the water exits back into the river through this breach that opened up in the January flood.Between the new entrance and exit from the pond, the Northpark ditch enters the river from Oakhurst and Northpark Woods.
Impacts Associated with Pit Capture
Without a river to remove sand from the confluence with the ditch, more and more sediment will likely build up here.
In regard to the last point, sand mining also frequently stirs up heavy metals such as lead and cadmium, which have been documented in academic literature. However, I have no evidence that such chemicals are coming from the Hallett Mine.
This river, which now flows through the Hallett pit, flows into Lake Houston. And Lake Houston is the source of drinking water for more than 2 million people.
Posted by Bob Rehak on May 11, 2024
2448 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/05/20240511-DJI_20240511084429_0574_D.jpg?fit=1100%2C619&ssl=16191100adminadmin2024-05-11 11:28:382024-05-14 17:08:58San Jacinto West Fork Reroutes Itself Through Giant Hallett Mine
May 10, 2024 – The floodwaters have finally receded. The sun has come out. And the debris piles are ba-aack. People who flooded during the storms last week are taking advantage of the break in weather to muck out their homes, toss wallboard, and cart waterlogged furniture to the curb.
Nowhere in Kingwood was the flooding worse than on Dunnam Road where Taylor Gully, Caney Creek, White Oak Creek, Peach Creek and the East Fork San Jacinto all come together. At least six homes and a business flooded. And badly.
Today, I visited the area again to survey the damage and talk to the survivors. For the people who live there, it was like the Boulevard of Broken Dreams.
Photos Taken 5/10/24 on Dunnam Road
This isn’t the first time that Dunnam Road flooded. And it won’t be the last. Part of it is low and close to the river.
The flooding seemed especially poignant this time, however, because the heaviest rains fell more than 60 miles away and worked their way downstream over a period of several days.
The floodwater even peaked briefly and started to recede. This may have given many people false hope that they wouldn’t flood, despite the Harris County meteorologist’s warnings to evacuate.
West side of Dunnam is filled with debris piles.East side is also filled with debris piles. Note how force of water pushed fence in.Looking uphill toward higher ground.I think they’ll be needing more buckets and scrub brushes.This lady and her husband just moved here from El Paso by way of Tucson and LA. They wanted a place that wasn’t so dry and found Houston. She’s 5’6″ tall. So you can see how deeply their home flooded.Carrying all your belongings to the curb. Flooded closets and driers left people with only one option. The backyard fence.Previously flooded vacant home.This is a very patriotic community and many homes will need new flags.Oblivious to the tragedy and just happy to be in Grandma’s arms as she surveys neighbors’ damage.
Posted by Bob Rehak on 5/10/24
2446 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/05/20240510-RJR_3507.jpg?fit=1100%2C733&ssl=17331100adminadmin2024-05-10 17:54:392024-05-10 18:03:29Boulevard of Broken Dreams: Debris Piles are Ba-aack
Construction is always the riskiest period during a development project. Especially when you clearcut 533 acres and get 17 inches of rain … in a week. However, thanks to best practices and luck, most people surrounding the Sila development in Huffman narrowly escaped what could have become a major disaster.
As the people in Woodridge Village learned repeatedly on far less rain, best practices can make all the difference. They lived near a development where stormwater detention basins were not built before the rain; the people near Sila did.
The new 553-acre Sila Project in Huffman on the East Fork of the San Jacinto seems to have had considerably less impact on neighbors. This is a story of people caught between a rising river and sheet flow coming down a slope.
Sila’s Similarities, Differences with Woodridge
Several similarities with the Woodridge project exist. Sila is big. Built on an identical slope. And clearcut. But after 17 inches of rain last week, the outcome was dramatically different.
Instead of flooding hundreds of homes below the development as Woodridge did, most residents near Sila only got water in their yards. One fish pond was ruined. At least two vehicles flooded. And at least one garage flooded.
The big differences between Sila and Woodridge?
Sila had already built stormwater detention basins. When the rain hit, a series of berms and ditches helped funnel runoff to the basins and away from neighbors. Silt fences intercepted much of the runoff. And crews replaced the fences when silt started to spill over the top.
Before looking at pictures, first let’s look at some stats that put the rainfall in perspective.
5- To 25-Year Rainfall
After Sila weathered this year’s January rains, it got slammed again in the week between April 29 and May 5 with almost 17 inches of rainfall.
That included 7 inches in one day. And half of that fell in one hour.
Of the 17 inches, 7.12 inches fell on 5/2/24 alone, with 3.48 inches in one hour.
NOAA defines a 7-day/17.1 inch rain in this area as a 25-year rainfall. Ditto for a one-hour 3.88 inch rain. Seven inches in one day, however, is only a 5-year event.
However, the East Fork peaked at FM1485 at a level equal to a 500-year flood according to Harris County Flood Control’s Flood Warning System. That’s because even heavier rain fell upstream in less time. It then reached FM1485 when heavy rains were falling there.
East Fork peaked over 77 feet at FM1485 on May 5.According to HCFCD, 77 feet is more than a 500-year rain.
Also, according to HCFCD, to date, the area near FM1485 has received more than two thirds of a year’s average annual rainfall in about one third of the year – 34.72 inches!
Pictures Taken During Week of Heavy Rains
Northwood Country Estates resident Max Kidd provided many of the following photos taken at ground level during the flood.
They show mainly severe street flooding. Thankfully, Harris County Precinct 3 Commissioner Tom Ramsey’s crews had just finished cleaning roadside ditches. Otherwise these photos might have told a much worse story.
Water poured out of Sila across Northwood Country Road on 5/2, the day before the big rain.
On 5/3 and 5/4/24, Kidd took these photos.
Flooded home and vehicles.
Kidd believes the home above likely flooded from the East Fork. However, Sila runoff may have added to the flood depth.
Photos Taken After the Storm
Sila is so big that it’s hard to get it all in one shot. The aerial shots below were all taken on 5/6/24 after the rain ended.
Looking E across the southern portion of Sila. St. Tropez, a separate development is at very top of frameacross FM2100. But Sila drains to the East Fork, and St. Tropez drains to Luce Bayou.Luce later re-enters the East Fork near its mouth at the headwaters of Lake Houston.Sila had a swale behind the erosion to slow water running down a hill out of frame to the left. However, that swale filled in with sediment, according to Kidd. And water then flowed into a ditch behind the fence filling it with sediment, too. Still, some sediment flooded into the backyards of neighbors.A series of detention basins caught and channeled runoff through the development.Shortly after the rain ended, it appears that bulldozers graded perpendicular to slopes to help retain or slow down any additional rain that might fall.
In the photo below, also note the forested corridors that break up Sila runoff. While large portions have been clear cut, those that haven’t help retain sediment.
Detention basin was holding water and emptying it slowly, presumably at the pre-development runoff rate.Still, some sediment escaped the development. Note roadside ditch filling in at peak of triangle.
As I left after this photo session, I noticed workers replacing and reinforcing the silt fence above. But the photo below shows the volume of the sediment that escaped despite their efforts. A lot!
Drainage had filled in completely.Kidd’s fish pond is no longer habitableby fishdue to Sila runoff that polluted it.Lowest of the detention basins at southwestern edge of development was sending stormwater into a wetland mitigation bank before it reached the East Fork.Contractors had put silt fence at the outfall of the detention basin to help retain sediment.But then they pumped water toward the river, through a mass of muck, creating more erosion.(Can’t win ’em all.)Along the way to the river, some of the dirt will get a chance to settle out in the wetland mitigation bank.Regardless, the East Fork was running orange on 5/6/24.
No doubt, several sources contributed to the discoloration. They include Sila, other upstream developments, sand mines and natural, river-bank erosion.
Few developments that I have observed go to as much trouble to control runoff as Sila. And few bother to leave trees these days. I wish more did. We might have less sediment clogging our rivers and contributing to downstream flooding.
Posted by Bob Rehak on 5/9/24
2445 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2024/05/20240410-DJI_20240410115740_0182_D.jpg?fit=1100%2C619&ssl=16191100adminadmin2024-05-09 07:03:052024-05-11 21:05:09They Clearcut 533 Acres, Then Got 17 Inches of Rain
San Jacinto West Fork Reroutes Itself Through Giant Hallett Mine
Correction: This sand pit in this post was sold by Hallett to Riverwalk Porter LLC on January 23, 2024.
The San Jacinto West Fork has become totally blocked by sediment at the Hallett Mine in Porter and rerouted itself through the giant sand mine.
The old river channel has been sealed off by sediment. And the river now enters and exits one of the mine’s largest pits through large breaches in what used to be dikes. See below.
More than Normal Erosion
Rivers always move during floods through erosion. But this represents a far larger than normal amount of movement through a process called pit capture.
The loss of the dikes is likely the result of the SJRA releasing 71,000 cubic feet per second from Lake Conroe during the peak of the recent flood. That was the second largest release in the history of the SJRA.
Pictures taken just before the peak of the flood show the river already overtopping the pit’s dike. Dikes like walls that separate the river from the mine’s pits. They keep industrial wastewater out of your drinking water.
Weak Sand Mining Regulations Brought This On
Two other contributing factors are the depth of the pit compared to the river and the width of the dike.
Until recently, Texas was one of the few states (if not the only one) that had no minimum setbacks of mines from rivers. Bill McCabe of the Lake Houston Area Flood Prevention Initiative was instrumental in lobbying for greater setbacks. The TCEQ adopted them in 2021, but this pit predated the new regulation. And the TCEQ did not enforce the regulation in this case.
In fact, this pit was open on its southern end since January. That breach was already expanding before the recent flood.
Pictures Taken Before and After Flood Show Pit Capture
Pictures taken during and after the flood show the impact.
Following the river around to the right, you can see how much sand the river laid down. This likely happened when the volume of water moving through the channel decreased as the velocity decreased, allowing suspended sediment to drop out of suspension.
This video shows the height of the sand deposited in the river bed when the river started flowing to the pit instead of following its normal channel.
Impacts Associated with Pit Capture
Without a river to remove sand from the confluence with the ditch, more and more sediment will likely build up here.
Academic literature discusses the impact of “pit capture” on:
In regard to the last point, sand mining also frequently stirs up heavy metals such as lead and cadmium, which have been documented in academic literature. However, I have no evidence that such chemicals are coming from the Hallett Mine.
This river, which now flows through the Hallett pit, flows into Lake Houston. And Lake Houston is the source of drinking water for more than 2 million people.
Posted by Bob Rehak on May 11, 2024
2448 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.
Boulevard of Broken Dreams: Debris Piles are Ba-aack
May 10, 2024 – The floodwaters have finally receded. The sun has come out. And the debris piles are ba-aack. People who flooded during the storms last week are taking advantage of the break in weather to muck out their homes, toss wallboard, and cart waterlogged furniture to the curb.
Nowhere in Kingwood was the flooding worse than on Dunnam Road where Taylor Gully, Caney Creek, White Oak Creek, Peach Creek and the East Fork San Jacinto all come together. At least six homes and a business flooded. And badly.
Today, I visited the area again to survey the damage and talk to the survivors. For the people who live there, it was like the Boulevard of Broken Dreams.
Photos Taken 5/10/24 on Dunnam Road
This isn’t the first time that Dunnam Road flooded. And it won’t be the last. Part of it is low and close to the river.
The flooding seemed especially poignant this time, however, because the heaviest rains fell more than 60 miles away and worked their way downstream over a period of several days.
The floodwater even peaked briefly and started to recede. This may have given many people false hope that they wouldn’t flood, despite the Harris County meteorologist’s warnings to evacuate.
Posted by Bob Rehak on 5/10/24
2446 Days since Hurricane Harvey
They Clearcut 533 Acres, Then Got 17 Inches of Rain
Construction is always the riskiest period during a development project. Especially when you clearcut 533 acres and get 17 inches of rain … in a week. However, thanks to best practices and luck, most people surrounding the Sila development in Huffman narrowly escaped what could have become a major disaster.
As the people in Woodridge Village learned repeatedly on far less rain, best practices can make all the difference. They lived near a development where stormwater detention basins were not built before the rain; the people near Sila did.
The new 553-acre Sila Project in Huffman on the East Fork of the San Jacinto seems to have had considerably less impact on neighbors. This is a story of people caught between a rising river and sheet flow coming down a slope.
Sila’s Similarities, Differences with Woodridge
Several similarities with the Woodridge project exist. Sila is big. Built on an identical slope. And clearcut. But after 17 inches of rain last week, the outcome was dramatically different.
Instead of flooding hundreds of homes below the development as Woodridge did, most residents near Sila only got water in their yards. One fish pond was ruined. At least two vehicles flooded. And at least one garage flooded.
The big differences between Sila and Woodridge?
Sila had already built stormwater detention basins. When the rain hit, a series of berms and ditches helped funnel runoff to the basins and away from neighbors. Silt fences intercepted much of the runoff. And crews replaced the fences when silt started to spill over the top.
Before looking at pictures, first let’s look at some stats that put the rainfall in perspective.
5- To 25-Year Rainfall
After Sila weathered this year’s January rains, it got slammed again in the week between April 29 and May 5 with almost 17 inches of rainfall.
That included 7 inches in one day. And half of that fell in one hour.
NOAA defines a 7-day/17.1 inch rain in this area as a 25-year rainfall. Ditto for a one-hour 3.88 inch rain. Seven inches in one day, however, is only a 5-year event.
However, the East Fork peaked at FM1485 at a level equal to a 500-year flood according to Harris County Flood Control’s Flood Warning System. That’s because even heavier rain fell upstream in less time. It then reached FM1485 when heavy rains were falling there.
Also, according to HCFCD, to date, the area near FM1485 has received more than two thirds of a year’s average annual rainfall in about one third of the year – 34.72 inches!
Pictures Taken During Week of Heavy Rains
Northwood Country Estates resident Max Kidd provided many of the following photos taken at ground level during the flood.
They show mainly severe street flooding. Thankfully, Harris County Precinct 3 Commissioner Tom Ramsey’s crews had just finished cleaning roadside ditches. Otherwise these photos might have told a much worse story.
On 5/3 and 5/4/24, Kidd took these photos.
Kidd believes the home above likely flooded from the East Fork. However, Sila runoff may have added to the flood depth.
Photos Taken After the Storm
Sila is so big that it’s hard to get it all in one shot. The aerial shots below were all taken on 5/6/24 after the rain ended.
In the photo below, also note the forested corridors that break up Sila runoff. While large portions have been clear cut, those that haven’t help retain sediment.
As I left after this photo session, I noticed workers replacing and reinforcing the silt fence above. But the photo below shows the volume of the sediment that escaped despite their efforts. A lot!
No doubt, several sources contributed to the discoloration. They include Sila, other upstream developments, sand mines and natural, river-bank erosion.
Few developments that I have observed go to as much trouble to control runoff as Sila. And few bother to leave trees these days. I wish more did. We might have less sediment clogging our rivers and contributing to downstream flooding.
Posted by Bob Rehak on 5/9/24
2445 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.