Sand mining best practices throughout the country and the world urge operators to leave vegetation in place until they are ready to mine an area. The reason: to reduce erosion. However, approximately 60 acres of the sand mine below on the East Fork of the San Jacinto where it meets Caney Creek and White Oak Creek was cleared but not mined – just in time for two 500-year floods.
Approximately 65 acres of this mine were cleared before two five-hundred year floods, contributing to downstream sedimentation in the East Fork, even though only about three acres of the area was mined.
The cleared area lies totally in the 100-year flood plain and was inundated. Satellite images of the area downstream from the cleared land show a sudden buildup of sand. While the sand did not all come from the cleared area, one wonders how much sedimentation could have been prevented by following best practices.
The following sequence of images shows the rapid removal of vegetation.
The white outlined area will be totally cleared before Harvey. On April 8, 2014, it was all dense forest.
By March 3, 2016, most of the area was cleared.
By January 23, 2017, just before Harvey, the area was entirely cleared.
Risk from Flooding
This FEMA flood hazard map shows that the entire area lies within with 100-year flood plain (aqua) and adjacent to the floodway (cross-hatched area).
Before and After: Results
This image from 2014 shows the area in question when it was still forested. Note how little sand is in the river downstream from the mine.
Here’s the same view after vegetationwas cleared and the area was inundated by Harvey in 2017. Note all the sediment in the river downstream.
Much of the sand and sediment washed downstream is invisible to satellite photos because it’s under dense forest canopy. This area (downstream the sand mine being discussed) was once wetlands. A boardwalk through those wetlands had to be excavated from several feet of sand after Harvey.
Here’s what part of the same trail looked like before it was excavated. Approximately 30 acres of the park were blanketed with dunes up to 10 feet tall after Harvey. Every trail in the park required repairs. Total cost: approximately $200,000 to Kingwood residents.
A bird’s nest that was ten feet up in a tree is now knee high. Many of the trees along the Eagle Point trail in East End Park are buried under so much sand that they are dying.
An Ounce of Prevention
It’s impossible to tell how much of the sand above resulted from the removal of vegetation? Previous posts showed how the mines stockpile also eroded. The river itself contributed sediment. However, if the mine were not in the flood plain and if the miners had not removed so much vegetation so far in advance of mining, we wouldn’t be having this discussion.
So why do miners favor the floodplains and floodways? Why to they remove vegetation years before it will be mined? Is it all about the relentless pursuit of efficiency at the expense of safety?
Tomorrow, we will look at economics, taxation and how some well-intentioned laws passed in the late seventies to protect family farms helped fuel a boom in sand mining.
Posted September 24, 2018
391 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2018/09/Harvey-SanJac_374.jpg?fit=2000%2C1333&ssl=113332000adminadmin2018-09-24 02:26:442018-09-24 07:46:37Sand Mining Best Management Practices: Vegetation
The things government does now to protect us from future flooding – and the speed with which it does them – will make the difference between long-term recovery and decay.
In many ways, we’ve made incredible progress since Harvey – the initial frenzy of volunteerism, the massive trash pickup, repairing homes, re-establishing businesses, rebuilding infrastructure, re-opening schools, organizing an emergency (albeit partial) dredging project, passing a $2.5 billion flood bond, and more. The amount of activity speaks volumes about the character of the community. But recovery is far from complete.
The old HEB store still has not been leased to a new tenant.
Confidence determines whether people will rebuild. Without confidence, people are reluctant to invest. You can see lack of confidence in empty shops up and down West Lake Houston Parkway and in “for sale” signs in front of homes. People are saying, “I’m not going to risk this again.”
So what will give people confidence and speed recovery?
Expand Dredging
The Army Corps has started dredging a small portion of the West Fork – about 1.2 miles between Kings Lake Estates and River Grove Park. This will take until April or May of next year to complete. However, the biggest blockage in the river is NOT part of this project. The “mouth bar” where the river meets the lake will remain. Unless a second project to address that can be funded, bid and mobilized before the first is done, taxpayers will be forced to pay another $18 million in mobilization/demobilization fees – all over again.
First dredge on the San Jacinto is now working an area west of the West Lake Houston Parkway Bridge. Photo courtesy of Keith Jordan.
Even if the mouth bar is addressed, the rest of the West Fork, the East Fork and parts of Lake Houston will need to be dredged in order to clear channels through the upper Lake Houston area.
To prevent the current blockages from recurring and flooding us again, we should also develop a maintenance dredging program in perpetuity.
FEMA defines floodways as the main channel of the river during a flood – where the water moves the fastest. With the exception of one sand mine between Lake Houston and I-45, part of every single sand mine lies in the floodway.
West Fork sand mines on 8/30/17, one day after the peak from from Harvey
We’ve seen several instances of ruptured mine dikes on the West Fork – some that have gone unprepared for years and increased the rate of sedimentation. This contributes to the sand and sediment clogging our rivers, the destruction of downstream properties, and dredging costs which are substantial.
Improve Ditch Maintenance
Harris County has agreed to take over ditch maintenance for the City of Houston. However, the City of Houston is still looking for deeds and easements that should have been transferred and recorded during annexation 22 years ago. This does NOT inspire confidence. Once the County receives permission to clean and clear the ditches, it can proceed. County flood control crews have been surveying in anticipation of receiving the documents. Money has also been freed up in the Flood Control budget with the passage of the flood bond.
We should also remember that more water came down the East Fork during the peak of Harvey than the West Fork. Additional upstream detention on both forks will help reduce the input during floods and raise confidence.
Add More Flood Gates to Lake Houston
In March, the Mayor promised 10 additional flood gates for Lake Houston so that we could shed water faster during a flood. This pr0ject has progressed somewhat since then, but slowly. The City has filed an application with FEMA which has received a high score from the Texas Division of Emergency Management (TDEM). TDEM ranks applications for FEMA funding coming from Texas.
Nonetheless, some officials have said that additional gates could take 10 years to actually build. Given the fact that we’ve had five so-called “500-year storms” in the last 25 years (1994, 2001, 2015, 2016, 2017), 10 years is too long. Many older residents won’t live long enough to see those gates. We can and must do better. We won World War II in less than half that time.
Plead for Speed
Delays in these mitigation projects will undermine confidence and recovery. Conversely, fast-tracking these projects will restore confidence and speed recovery.
We also need to streamline government disaster recovery. Let’s face it. It has taken more than a year since Hurricane Harvey to get one dredge on the San Jacinto River. We can do better. We need to do better.
As always, these are my opinions on matters of public policy protected by the First Amendment of the United States Constitution and the Anti-SLAPP statute of the Great State of Texas.
Posted by Bob Rehak on September 22, 2018
389 Days Since Hurricane Harvey
00adminadmin2018-09-22 01:42:222018-09-22 08:11:10Opportunities to Speed Recovery
The Army Corps of Engineers Emergency West Fork Dredging Project started yesterday, but not where planned. The Corps originally said it would start slightly east of West Lake Houston Parkway bridge and work its way back west to River Grove Park. Contract documents indicated the eastward limit of dredging would include the area south of Kings Harbor. However, today dredging started west of the bridge, between the Kingwood Country Club Forest Course and Kings Lake Estates. That puts the start of dredging approximately in the middle of the contracted area.
From US Army Corps’ contract plans for West Fork Dredging project. Note arrow pointing to power lines in C-102.
Photo courtesy of Keith Jordan, a Kings Lake Estates resident, shows first dredge set up behind row of trees on West Fork. Note high tension power lines seen in the right of photo as a reference to the map above.
Jordan said, “Literally watching constant dredging occurring about 200 yards in front of my boat house in the river. Motors seem to be running 24/7 with lights on boats at night.” He later sent me this image.
Photo Courtesy of Keith Jordan.
Approximate starting point of dredging. Satellite image courtesy of Google Earth.
When asked about noise from the operation, Jordan replied, “Just hear a steady hum from inside the house. Nothing bad.”
I asked about the change in plans because Kings Harbor was one of the worst flooded areas in Kingwood. One hundred percent of the businesses were destroyed along with three apartment complexes. This is also the area were Ben’s Branch empties into the river.
The Corps has not yet explained the reason for the change in plans. They did, however, send these additional shots of the dredge in operation.
First dredge in operation on location in the middle of the contracted area.
First dredge at work near Kings Lake Estates. There appears to be a mechanical dredge working in front of the hydraulic dredge.
The dredge weighs approximately 27 tons and will be in the river 24 hours per day until early May of 2019 according to the Corps.
Over 4.5 miles of high density polyethylene pipeline measuring 24 inches in diameter is in position and will help move over 1.8 million cubic years of sediment and debris.
Corps officials are asking recreational boaters to stay clear of the dredge and be aware of debris removal pipelines and booster pumps within the river.
Posted by Bob Rehak on 9/20/18
388 Days since Hurricane Harvey
00adminadmin2018-09-20 23:35:382018-09-21 11:12:49Dredging Starts, But Not Where Planned
Sand Mining Best Management Practices: Vegetation
Sand mining best practices throughout the country and the world urge operators to leave vegetation in place until they are ready to mine an area. The reason: to reduce erosion. However, approximately 60 acres of the sand mine below on the East Fork of the San Jacinto where it meets Caney Creek and White Oak Creek was cleared but not mined – just in time for two 500-year floods.
Approximately 65 acres of this mine were cleared before two five-hundred year floods, contributing to downstream sedimentation in the East Fork, even though only about three acres of the area was mined.
Removing Vegetation Risks Sedimentation Downstream
The cleared area lies totally in the 100-year flood plain and was inundated. Satellite images of the area downstream from the cleared land show a sudden buildup of sand. While the sand did not all come from the cleared area, one wonders how much sedimentation could have been prevented by following best practices.
The following sequence of images shows the rapid removal of vegetation.
The white outlined area will be totally cleared before Harvey. On April 8, 2014, it was all dense forest.
By March 3, 2016, most of the area was cleared.
By January 23, 2017, just before Harvey, the area was entirely cleared.
Risk from Flooding
This FEMA flood hazard map shows that the entire area lies within with 100-year flood plain (aqua) and adjacent to the floodway (cross-hatched area).
Before and After: Results
This image from 2014 shows the area in question when it was still forested. Note how little sand is in the river downstream from the mine.
Here’s the same view after vegetationwas cleared and the area was inundated by Harvey in 2017. Note all the sediment in the river downstream.
Much of the sand and sediment washed downstream is invisible to satellite photos because it’s under dense forest canopy. This area (downstream the sand mine being discussed) was once wetlands. A boardwalk through those wetlands had to be excavated from several feet of sand after Harvey.
Here’s what part of the same trail looked like before it was excavated. Approximately 30 acres of the park were blanketed with dunes up to 10 feet tall after Harvey. Every trail in the park required repairs. Total cost: approximately $200,000 to Kingwood residents.
A bird’s nest that was ten feet up in a tree is now knee high. Many of the trees along the Eagle Point trail in East End Park are buried under so much sand that they are dying.
An Ounce of Prevention
It’s impossible to tell how much of the sand above resulted from the removal of vegetation? Previous posts showed how the mines stockpile also eroded. The river itself contributed sediment. However, if the mine were not in the flood plain and if the miners had not removed so much vegetation so far in advance of mining, we wouldn’t be having this discussion.
So why do miners favor the floodplains and floodways? Why to they remove vegetation years before it will be mined? Is it all about the relentless pursuit of efficiency at the expense of safety?
Tomorrow, we will look at economics, taxation and how some well-intentioned laws passed in the late seventies to protect family farms helped fuel a boom in sand mining.
Posted September 24, 2018
391 Days since Hurricane Harvey
Opportunities to Speed Recovery
The things government does now to protect us from future flooding – and the speed with which it does them – will make the difference between long-term recovery and decay.
In many ways, we’ve made incredible progress since Harvey – the initial frenzy of volunteerism, the massive trash pickup, repairing homes, re-establishing businesses, rebuilding infrastructure, re-opening schools, organizing an emergency (albeit partial) dredging project, passing a $2.5 billion flood bond, and more. The amount of activity speaks volumes about the character of the community. But recovery is far from complete.
The old HEB store still has not been leased to a new tenant.
Confidence determines whether people will rebuild. Without confidence, people are reluctant to invest. You can see lack of confidence in empty shops up and down West Lake Houston Parkway and in “for sale” signs in front of homes. People are saying, “I’m not going to risk this again.”
So what will give people confidence and speed recovery?
Expand Dredging
The Army Corps has started dredging a small portion of the West Fork – about 1.2 miles between Kings Lake Estates and River Grove Park. This will take until April or May of next year to complete. However, the biggest blockage in the river is NOT part of this project. The “mouth bar” where the river meets the lake will remain. Unless a second project to address that can be funded, bid and mobilized before the first is done, taxpayers will be forced to pay another $18 million in mobilization/demobilization fees – all over again.
First dredge on the San Jacinto is now working an area west of the West Lake Houston Parkway Bridge. Photo courtesy of Keith Jordan.
Even if the mouth bar is addressed, the rest of the West Fork, the East Fork and parts of Lake Houston will need to be dredged in order to clear channels through the upper Lake Houston area.
Reduce Sedimentation
Sedimentation comes from several sources: a) natural stream erosion, B) urbanization, and C) sand mining. With the exception of creating more upstream detention, we can’t do much to control A or B. We can, however, do something about the 20 square miles of sand mines in the floodways upstream from us.
FEMA defines floodways as the main channel of the river during a flood – where the water moves the fastest. With the exception of one sand mine between Lake Houston and I-45, part of every single sand mine lies in the floodway.
West Fork sand mines on 8/30/17, one day after the peak from from Harvey
Moving mines out of the floodway will require legislation that puts more distance between mines and rivers. As far as I can tell, Texas is the only state that does not require a minimum setback. We need greater setbacks because rivers migrate over time and capture pits during floods. This process is well understood and predictable.
We’ve seen several instances of ruptured mine dikes on the West Fork – some that have gone unprepared for years and increased the rate of sedimentation. This contributes to the sand and sediment clogging our rivers, the destruction of downstream properties, and dredging costs which are substantial.
Improve Ditch Maintenance
Harris County has agreed to take over ditch maintenance for the City of Houston. However, the City of Houston is still looking for deeds and easements that should have been transferred and recorded during annexation 22 years ago. This does NOT inspire confidence. Once the County receives permission to clean and clear the ditches, it can proceed. County flood control crews have been surveying in anticipation of receiving the documents. Money has also been freed up in the Flood Control budget with the passage of the flood bond.
Create More Upstream Detention
Holding water upstream during a flood lowers water levels downstream. The County has identified potential land to build another reservoir on far western Cypress Creek. That should help. But it’s a long term project and one of hundreds in the flood bond package.
We should also remember that more water came down the East Fork during the peak of Harvey than the West Fork. Additional upstream detention on both forks will help reduce the input during floods and raise confidence.
Add More Flood Gates to Lake Houston
In March, the Mayor promised 10 additional flood gates for Lake Houston so that we could shed water faster during a flood. This pr0ject has progressed somewhat since then, but slowly. The City has filed an application with FEMA which has received a high score from the Texas Division of Emergency Management (TDEM). TDEM ranks applications for FEMA funding coming from Texas.
Nonetheless, some officials have said that additional gates could take 10 years to actually build. Given the fact that we’ve had five so-called “500-year storms” in the last 25 years (1994, 2001, 2015, 2016, 2017), 10 years is too long. Many older residents won’t live long enough to see those gates. We can and must do better. We won World War II in less than half that time.
Plead for Speed
Delays in these mitigation projects will undermine confidence and recovery. Conversely, fast-tracking these projects will restore confidence and speed recovery.
We also need to streamline government disaster recovery. Let’s face it. It has taken more than a year since Hurricane Harvey to get one dredge on the San Jacinto River. We can do better. We need to do better.
As always, these are my opinions on matters of public policy protected by the First Amendment of the United States Constitution and the Anti-SLAPP statute of the Great State of Texas.
Posted by Bob Rehak on September 22, 2018
389 Days Since Hurricane Harvey
Dredging Starts, But Not Where Planned
The Army Corps of Engineers Emergency West Fork Dredging Project started yesterday, but not where planned. The Corps originally said it would start slightly east of West Lake Houston Parkway bridge and work its way back west to River Grove Park. Contract documents indicated the eastward limit of dredging would include the area south of Kings Harbor. However, today dredging started west of the bridge, between the Kingwood Country Club Forest Course and Kings Lake Estates. That puts the start of dredging approximately in the middle of the contracted area.
From US Army Corps’ contract plans for West Fork Dredging project. Note arrow pointing to power lines in C-102.
Photo courtesy of Keith Jordan, a Kings Lake Estates resident, shows first dredge set up behind row of trees on West Fork. Note high tension power lines seen in the right of photo as a reference to the map above.
Jordan said, “Literally watching constant dredging occurring about 200 yards in front of my boat house in the river. Motors seem to be running 24/7 with lights on boats at night.” He later sent me this image.
Photo Courtesy of Keith Jordan.
Approximate starting point of dredging. Satellite image courtesy of Google Earth.
When asked about noise from the operation, Jordan replied, “Just hear a steady hum from inside the house. Nothing bad.”
I asked about the change in plans because Kings Harbor was one of the worst flooded areas in Kingwood. One hundred percent of the businesses were destroyed along with three apartment complexes. This is also the area were Ben’s Branch empties into the river.
The Corps has not yet explained the reason for the change in plans. They did, however, send these additional shots of the dredge in operation.
First dredge in operation on location in the middle of the contracted area.
First dredge at work near Kings Lake Estates. There appears to be a mechanical dredge working in front of the hydraulic dredge.
Over 4.5 miles of high density polyethylene pipeline measuring 24 inches in diameter is in position and will help move over 1.8 million cubic years of sediment and debris.
Posted by Bob Rehak on 9/20/18
388 Days since Hurricane Harvey