After 2.5 years of examining photos and videos of the so-called “dikes” in sand mines, I have come to believe that some are designed to fail. In some cases, mines cause them to fail.
In most cases, the “dikes” are not really dikes. They’re just the edges of pits that miners have excavated. Or roads around the pits made of sand that easily erode.
And because miners mine so close to the river, when those pits fill with water, they overflow. The resulting erosion cuts channels between the pit and the river that allow the pits to discharge a portion of their wastewater. Lake Houston and public drinking water become collateral damage.
High Cost of Flimsy Construction
After the storm, miners throw some sand in the breach and wait for it to happen again. The sand creates only the appearance of a fix.
Month after month, I’ve photographed active breaches, “patched” breaches, and scars in the landscape from older breaches. Many reopen multiple times.
Breaches are so common that, in my opinion, they may be part of some miners’ business plans.
High Cost of Silt
If discharges consisted of plain water, I might not care. But the water usually carries silt with it. Miner’s settling ponds can fill with silt which has little marketable value. Flushing it downriver solves another problem.
Miners externalize their cleanup costs by foisting them off on an unsuspecting public. That sediment clogs rivers that must be dredged to avoid flooding. It reduces the capacity of the lake. And it escalates the City’s water treatment costs.
A retired high-level Public Works manager told me he routinely investigated and found breaches at sand mines during floods. In his opinion, many of the breaches were intentional and the floods created the perfect “cover” for the illegal discharges. “Blame it on Mother Nature,” he said.
West Fork Images from February Flyover
Below, a sampling of more than 1000 images I took on 2/13/2020. The first batch shows mines on the San Jacinto West Fork between SH242 and US59. I traveled NW to SE toward 59. I’ve arranged images in the same order.
Sand mine pond and water’s path to the river (right).Pond is full to the brim and will overflow on a minor rain.
Another angle looking north toward the same breach.
West Fork is migrating toward pit on right and will soon enter it. A powerful argument for reasonable setbacks from river.
Another pond at the same mine. The only thing holding back another illegal discharge is a feeble road made of sand. See close up in next pic of area near poll just left of center.
Close up of road in upper left of previous photo. Note how water seeping through it is already causing road to collapse.
Silt spreading into settling pond. See also reverse shot below.
Reverse angle from previous shot, but same pond. See West Fork in background and note how road in foreground was cut by spreading silt.
Site of previous double breach at RGI mine. Note gray area in second row of dikes. Process water from the pond behind it broke into the settling pond in the foreground and from there into the West Fork. TCEQ cited owners.
Two separate ponds may have shared this same “wash” to the river (foreground). Pond in middle right is actively discharging into river. See reverse angle in next shot.
Same discharge as in previous shot. From this angle it is easier to see the active discharge.
Same breach from third angle. From this angle, you can clearly see the path and the discharge.
This pond has been discharging into the river for months. Note the difference in the color of the river water and discharge water. This indicates the discharge water is still holding silt.
Reverse shot of same breach highlights both the path and the color difference of the discharge.
This pond is leaking into a drainage channel that parallels Northpark Drive south of Oakhurst.
Former breach at Eagle mine on Sorters Road. West Fork in foreground.
Scars from previous breaches. One of these was intentional, though I’m not sure which. See video below.
Video by resident who wishes to remain anonymous shows intentional breach at the mine above.
Another scar from previous breach.
Confluence of Spring Creek (left) and West Fork San Jacinto (right).Facing west.Note color difference in water. It’s frequently visible.
Same area looking southeast toward Humble.West Fork on left.
Same area looking NE toward Kingwood.West Fork comes in from left.Between the 59 bridge in the previous shot and this area, the Army Corps spent more than $90 million removing sediment from the West Fork. The City, County and State could spend another $35 million removing this blockage.
Wider shot shows just how much forest was blown out in this breach, leading one to wonder whether this was caused solely by nature.Another former breach into Caney Creek from the Triple PG mine. Only this eroding road stands between the mine and the creek.
Also at the Triple PG mine in Porter, this breach into White Oak Creek remained open for months. It, too, was the subject the Attorney General’s lawsuit. A restraining order against the mine calls for repairs to be certified by a professional engineer. This looks as though they may have tried to add concrete to the sand and stabilize it with rebar. However, note that the concrete, if that’s what it is, doesn’t rise much above the water. The road is made from eroding sand that will blow out in the next storm.
Reverse shot of same breach looking west. No concrete or rebar visible here – only rilling along steep sides of road. Rilling is the term for those vertical erosion channels.
Posted by Bob Rehak on 2/24/2020
909 Days since Hurricane Harvey and 158 since Imelda
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/2020/02/20200213-RJR_7753.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-02-24 15:22:182020-02-24 15:29:12Are Sand Mine Dikes Designed to Fail?
In the last month, workers made progress on pipeline bed repairs to two area sand mines. But repairs at one sand mine look substantial. At another, they look superficial. Triple PG in Porter is still edging into the danger zone.
Exposed by Erosion When Mining Came Too Close
In December and January, I posted about pipelines exposed when sand miners mined too close to them. Floodwaters then swept through the mines and undercut the pipelines, creating safety hazards.
Pipelines exposed by erosion at Liberty Materials Mine in Conroe. Photo taken January 20, 2020.
Several HVL (highly volatile liquid) pipelines (above) and one natural gas pipeline (below) were affected at mines in Conroe and Porter.
Exposed natural gas pipeline at Triple PG mine near Caney Creek in Porter. Photo taken December 3, 2019.
Here’s where things stand on repairs at both mines as of last week..
Triple PG Mine in Porter: Another Big Cover Up
The Triple PG Mine in Porter has covered up the exposed natural gas pipeline with sand. As of 2/13/2020, Triple PG had made no other visible attempts to stabilize the area, which is subject to repeated erosion. Harvey first exposed the pipeline, which Triple PG subsequently covered. Then Imelda re-exposed it. And Triple PG re-covered it.
Fresh sand covers exposed natural gas pipeline. Will it be washed away a third time in the next big storm?
Readers may remember that after Harvey, Kinder Morgan tunneled 75 feet under the mine and spliced in a replacement for the section that had been exposed. They then filled the cutoff section with inert gas. So the exposed section was not active.
Still, without further stabilization, the pipeline will likely be exposed again and again by future storms.
Triple PG still has made no attempt to stabilize erosion creeping toward the HVL pipelines that cross the mine in a utility corridor. The same erosion that exposed the natural gas pipeline will threaten those in future storms.
Five pipelines carry highly volatile liquids through this utility corridor. Triple PG mines sand from either side of them. During floods, Caney Creek runs through this mine creating the erosion you see here.
Liberty Materials Mine in Conroe: Fix Nearing Completion
At a Liberty Materials Mine in Conroe, a much more substantial fix is underway by the pipelines. The mine spanned both sides of the utility corridor. Water from one side, trying to get to the river on the other, washed under several HVL pipelines, exposing them.
Repairs began in January and were well under way in February. Crews first expanded the washed out area under the pipelines. Then they placed two giant culverts under the pipelines to allow water to move from one side to the other. They also cemented the culverts in place and drove vertical steel reinforcements in the ground to prevent re-exposure of the pipelines.
Two giant culverts will now carry water under the pipelines. Shown above: the outfall.Steel reinforcements rise above the level of the pipelines to help retard erosion.Photo taken 2/13/2020.Rip rap and other reinforcements will also help retard erosion.Inlets for the culverts. Photo taken 2/13/2020.Looking west toward The Woodlands. San Jacinto West Fork is at far end of sand mine. Note all the sand and sediment that has washed under this area to the far side of the steel reinforcements.
As of 2/13/2020, crews were filling dirt in under, around and over the pipelines.
The repairs here appear much more substantial than in the Triple PG mine. I just hope the volume of sand washing from one section of the mine to the other does not clog the culverts. The steel reinforcements will protect the pipelines in this location, but water has a habit of flowing around obstacles.
Posted by Bob Rehak on 2/23/2020
908 Days after Hurricane Harvey 157 since Imelda
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/02/20200213-RJR_7697.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-02-23 10:43:352020-02-23 10:57:20Progress on Pipeline Repairs at Sand Mines
What causes street flooding? At the risk of clarifying the obvious, rain accumulates faster than storm sewers and drainage ditches can carry it away.
A Lack-Of-Capacity Issue
Most streets are actually designed to be part of the flood retention system in any community. That’s because most storm sewers can only handle a two-year rain (about 2 inches per hour). When we get more than that – say a 10-, 25-, 50- or 100-year rain – water is stored in the street until capacity opens up in the storm sewers, ditches and creeks.
As you can see from the new Atlas-14 rainfall chart below, a 2-year rain in this area is 2.23 inches/hour; a 25-year rain 3.88 inches/hour; and a 100-year rain 4.88.
New Atlas-14 Rainfall Data for Lake Houston area from NOAA
When evaluating rainfalls, look at the storm totals AND shorter intervals, such as 15, 30 and 60 minutes.
Street flooding usually results from short, high-intensity downpours caused by slow-moving or training thunderstorms.
From a street-flooding perspective, getting 4 inches of rain in one day is not the same as getting 4 inches in one hour.
If you get 2 inches of rain in 30 minutes, you’re already at a 5-year rain. That’s well beyond the design capacity of storm sewers. You can expect water to back up into the street at that point, even if there are no blockages in the storm sewers.
That’s why builders elevate most homes several feet above street level and above the 100-year flood plain. It gives you an additional margin of safety.
How To Determine Intensity of Rainfalls
If you flooded from your street, first determine whether the cause was simply overwhelming rainfall or whether complicating factors existed.
How can you determine how much rain you got in any given time interval during a storm? Follow these simple steps:
Click on the gage nearest you. (For me, that’s Gage #755 at the San Jacinto West Fork and West Lake Houston Parkway. I will use that in the example below.)
In the pop-up window, click on the “For More Information” button.
At the top of the next window, select date and time intervals. The Time Interval varies from One Hour to One Year. I selected September 19, 2019 (the day of Imelda) and 24 hours. That shows me 24 1-hour intervals. From this and the table above, you can see that we had three very intense hours in a row during Imelda.
HarrisCountyFWS.org shows we got almost 11 inches during Imelda, the vast majority of it in three hours.Note: selecting other time intervals displays other time increments.For instance the system breaks hours down into 5-minute increments, years into months, etc.
From the two charts above, correlate the actual precipitation with the recurrence intervals. You can see that…
We had a 10-year rain, followed by a 5-year rain, followed by a 2-year rain – all in three hours!
Every single one of those hours met or exceeded the maximum capacity of the storm sewers. So it’s easy to see WHY we had street flooding.
When Street Flooding Turns into Home Flooding
In a small percentage of cases, street flooding turns into HOME flooding – when there simply isn’t enough backup capacity in the streets. (In the following discussion, I’m EXCLUDING homes that flooded from rivers, streams, or overland sheet flow during Imelda, i.e., Ben’s Branch, Elm Grove, etc.).
Extreme events reveal the weaknesses in any system. If your home was:
At a low point on the street…
Near a clogged storm drain…
A foot or two lower than surrounding homes…
At the bottom of a hill…
In an area where water collected or converged…
Near an outfall pipe that collapsed or was blocked…
Upstream from a ditch that was blocked…
…you may have flooded.
And then there are the bizarre cases.
I visited one man in Trailwood at the bottom of a hill that had NO storm drains. Inexplicably, someone placed the nearest drain in the middle of the hill – about half a block ABOVE his home.
Another man called me who lived near Village Park Drive next to a tributary of Ben’s Branch. The Community Association had erected a fence between the end of the street and the tributary. They built the fence so low to the ground that it became clogged with weeds and grass clippings during Imelda and formed a dam. In the heavy rain, water could not get under it and backed up into his home.
What Can You Do?
Short of praying or digging up every street in Houston to enlarge the storm sewers, homeowners DO have some remedies.
Keep storm drains clear. Keep yard waste out of them.
Call 311 for a storm-drain inspection if you suspect yours have become clogged. The City is currently inspecting ALL drains in Kingwood subdivisions that had street flooding last year.
Inspect outfall pipes where your storm drains enter the nearest ditch to ensure they have not collapsed or become blocked.
Look out for new construction, such as the fence above, that may back water up. Remove or elevate the horizontal rot board if it blocks the overflow of water from your street.
If the problem recurs in less extreme events, consider flood proofing or elevating your home.
Make sure you have flood insurance; that it’s up to date; and that it reflects the true replacement value of your home.
Wide shot from farther up the block of fence shown above. Gap under fence did not exist at time of Imelda.Note how rot board has NOW been elevated to allow water collecting in street to get into creek beyond fence.
Great Options Where Possible
If your area floods repeatedly, you may also be interested in lobbying the City or County to build an overflow spillway or detention pond between your street and the nearest drainage channel. Obviously, geographic circumstances may rule this possibility out for many. But if you have a vacant lot in your neighborhood and a nearby ditch…
Example of community detention pond with overflow channel to Taylor Gully (beyond fence). This wasn’t enough to protect North Kingwood Forest in Imelda, but their problem was complicated by sheet flow from Woodridge Village.
Posted by Bob Rehak on 2/22/2020
907 Days after Hurricane Harvey and 156 after Imelda
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/02/20200203-RJR_7540.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-02-22 19:33:112020-02-23 04:47:14Street Flooding: Causes and Cures
Are Sand Mine Dikes Designed to Fail?
After 2.5 years of examining photos and videos of the so-called “dikes” in sand mines, I have come to believe that some are designed to fail. In some cases, mines cause them to fail.
In most cases, the “dikes” are not really dikes. They’re just the edges of pits that miners have excavated. Or roads around the pits made of sand that easily erode.
And because miners mine so close to the river, when those pits fill with water, they overflow. The resulting erosion cuts channels between the pit and the river that allow the pits to discharge a portion of their wastewater. Lake Houston and public drinking water become collateral damage.
High Cost of Flimsy Construction
After the storm, miners throw some sand in the breach and wait for it to happen again. The sand creates only the appearance of a fix.
Month after month, I’ve photographed active breaches, “patched” breaches, and scars in the landscape from older breaches. Many reopen multiple times.
Breaches are so common that, in my opinion, they may be part of some miners’ business plans.
High Cost of Silt
If discharges consisted of plain water, I might not care. But the water usually carries silt with it. Miner’s settling ponds can fill with silt which has little marketable value. Flushing it downriver solves another problem.
Miners externalize their cleanup costs by foisting them off on an unsuspecting public. That sediment clogs rivers that must be dredged to avoid flooding. It reduces the capacity of the lake. And it escalates the City’s water treatment costs.
A retired high-level Public Works manager told me he routinely investigated and found breaches at sand mines during floods. In his opinion, many of the breaches were intentional and the floods created the perfect “cover” for the illegal discharges. “Blame it on Mother Nature,” he said.
West Fork Images from February Flyover
Below, a sampling of more than 1000 images I took on 2/13/2020. The first batch shows mines on the San Jacinto West Fork between SH242 and US59. I traveled NW to SE toward 59. I’ve arranged images in the same order.
East Fork Images from February Flyover
Posted by Bob Rehak on 2/24/2020
909 Days since Hurricane Harvey and 158 since Imelda
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.
Progress on Pipeline Repairs at Sand Mines
In the last month, workers made progress on pipeline bed repairs to two area sand mines. But repairs at one sand mine look substantial. At another, they look superficial. Triple PG in Porter is still edging into the danger zone.
Exposed by Erosion When Mining Came Too Close
In December and January, I posted about pipelines exposed when sand miners mined too close to them. Floodwaters then swept through the mines and undercut the pipelines, creating safety hazards.
Several HVL (highly volatile liquid) pipelines (above) and one natural gas pipeline (below) were affected at mines in Conroe and Porter.
Here’s where things stand on repairs at both mines as of last week..
Triple PG Mine in Porter: Another Big Cover Up
The Triple PG Mine in Porter has covered up the exposed natural gas pipeline with sand. As of 2/13/2020, Triple PG had made no other visible attempts to stabilize the area, which is subject to repeated erosion. Harvey first exposed the pipeline, which Triple PG subsequently covered. Then Imelda re-exposed it. And Triple PG re-covered it.
Readers may remember that after Harvey, Kinder Morgan tunneled 75 feet under the mine and spliced in a replacement for the section that had been exposed. They then filled the cutoff section with inert gas. So the exposed section was not active.
Still, without further stabilization, the pipeline will likely be exposed again and again by future storms.
Triple PG still has made no attempt to stabilize erosion creeping toward the HVL pipelines that cross the mine in a utility corridor. The same erosion that exposed the natural gas pipeline will threaten those in future storms.
Liberty Materials Mine in Conroe: Fix Nearing Completion
At a Liberty Materials Mine in Conroe, a much more substantial fix is underway by the pipelines. The mine spanned both sides of the utility corridor. Water from one side, trying to get to the river on the other, washed under several HVL pipelines, exposing them.
Repairs began in January and were well under way in February. Crews first expanded the washed out area under the pipelines. Then they placed two giant culverts under the pipelines to allow water to move from one side to the other. They also cemented the culverts in place and drove vertical steel reinforcements in the ground to prevent re-exposure of the pipelines.
As of 2/13/2020, crews were filling dirt in under, around and over the pipelines.
The repairs here appear much more substantial than in the Triple PG mine. I just hope the volume of sand washing from one section of the mine to the other does not clog the culverts. The steel reinforcements will protect the pipelines in this location, but water has a habit of flowing around obstacles.
Posted by Bob Rehak on 2/23/2020
908 Days after Hurricane Harvey 157 since Imelda
Street Flooding: Causes and Cures
What causes street flooding? At the risk of clarifying the obvious, rain accumulates faster than storm sewers and drainage ditches can carry it away.
A Lack-Of-Capacity Issue
Most streets are actually designed to be part of the flood retention system in any community. That’s because most storm sewers can only handle a two-year rain (about 2 inches per hour). When we get more than that – say a 10-, 25-, 50- or 100-year rain – water is stored in the street until capacity opens up in the storm sewers, ditches and creeks.
As you can see from the new Atlas-14 rainfall chart below, a 2-year rain in this area is 2.23 inches/hour; a 25-year rain 3.88 inches/hour; and a 100-year rain 4.88.
When evaluating rainfalls, look at the storm totals AND shorter intervals, such as 15, 30 and 60 minutes.
From a street-flooding perspective, getting 4 inches of rain in one day is not the same as getting 4 inches in one hour.
If you get 2 inches of rain in 30 minutes, you’re already at a 5-year rain. That’s well beyond the design capacity of storm sewers. You can expect water to back up into the street at that point, even if there are no blockages in the storm sewers.
That’s why builders elevate most homes several feet above street level and above the 100-year flood plain. It gives you an additional margin of safety.
How To Determine Intensity of Rainfalls
If you flooded from your street, first determine whether the cause was simply overwhelming rainfall or whether complicating factors existed.
How can you determine how much rain you got in any given time interval during a storm? Follow these simple steps:
From the two charts above, correlate the actual precipitation with the recurrence intervals. You can see that…
Every single one of those hours met or exceeded the maximum capacity of the storm sewers. So it’s easy to see WHY we had street flooding.
When Street Flooding Turns into Home Flooding
In a small percentage of cases, street flooding turns into HOME flooding – when there simply isn’t enough backup capacity in the streets. (In the following discussion, I’m EXCLUDING homes that flooded from rivers, streams, or overland sheet flow during Imelda, i.e., Ben’s Branch, Elm Grove, etc.).
Extreme events reveal the weaknesses in any system. If your home was:
…you may have flooded.
And then there are the bizarre cases.
I visited one man in Trailwood at the bottom of a hill that had NO storm drains. Inexplicably, someone placed the nearest drain in the middle of the hill – about half a block ABOVE his home.
Another man called me who lived near Village Park Drive next to a tributary of Ben’s Branch. The Community Association had erected a fence between the end of the street and the tributary. They built the fence so low to the ground that it became clogged with weeds and grass clippings during Imelda and formed a dam. In the heavy rain, water could not get under it and backed up into his home.
What Can You Do?
Short of praying or digging up every street in Houston to enlarge the storm sewers, homeowners DO have some remedies.
Great Options Where Possible
If your area floods repeatedly, you may also be interested in lobbying the City or County to build an overflow spillway or detention pond between your street and the nearest drainage channel. Obviously, geographic circumstances may rule this possibility out for many. But if you have a vacant lot in your neighborhood and a nearby ditch…
Posted by Bob Rehak on 2/22/2020
907 Days after Hurricane Harvey and 156 after Imelda