Is Time Running Out for Sand?

Given the amount of sand we’re currently trying to remove from the mouth bar of the West Fork, this post may seem counter-intuitive to many. However…

Worldwide, sand is becoming scarce according to a number of recent reports and articles from respected sources. And as the scarcity transforms economies, it also transforms our environment.

Sand mine complex on the west fork of the San Jacinto adjacent to Kingwood.

Many now question the sustainability of an economy built on sand extraction from rivers and are exploring ways to reduce our dependence on that source … or import sand from places that are still producing it faster than they are using it.

Sand from Greenland?

An article in the New York Times points to people who are actually researching the feasibility of exporting sand produced by Greenland glaciers to Europe where river mining is outlawed in many countries. Such an endeavor would raise the cost of sand.

The article quotes Jason C. Willett, a minerals commodity specialist with the United States Geological Survey. “Currently almost all sand is mined within 50 miles of where it is used,” he said. “Once you move it any distance, it then costs too much.”

Regardless, the world makes so much concrete (more than 10 billion tons a year), that producers are investigating new ways to supply demand. Population is forecast to grow by more than 25 percent by 2050. “That makes sand, which is about 40 percent of concrete by weight, one of the most-used commodities in the world, and one that is becoming harder to come by in some regions,” says the Times.

Sand Extracted Faster than Nature Replacing It

Another article in the July 2019 international journal of science called Nature claims, “Sand and gravel are being extracted faster than they can be replaced.”

The article goes on to say:

  • Sand and gravel make up the most extracted group of materials, even exceeding fossil fuels1.
  • Urbanization and global population growth are fuelling an explosion in demand, especially in China, India and Africa2.
  • Roughly 32 billion to 50 billion tonnes are used globally each year, mainly for making concrete, glass and electronics3. (Note: this number is higher than the one quoted above but also includes additional uses.)
  • This exceeds the pace of natural renewal4 such that by mid-century, demand might outstrip supply2.
  • Desert sand grains are too smooth to be useful, and most of the angular sand that is suitable for industry comes from rivers (less than 1% of the world’s land)5.
  • This extraction of sand and gravel has far-reaching impacts on ecology, infrastructure and the livelihoods of the 3 billion people who live along rivers3,6,7

For example, the Nature article says, “In the Mekong delta, the Vietnamese government estimates that nearly 500,000 people will need to be moved away from river banks that are collapsing as a result of sand mining in the channel.”

Likewise, in Bangladesh, the Umngi River expanded when people started mining sand from the river bid.

From the July 2019 issue of Nature

UNEP Questions Sustainability

Another recent report by the United Nations Environment Program (UNEP) says, “Shifting consumption patterns, growing populations, increasing urbanization and infrastructure development have increased demand for sand three-fold over the last two decades,” claims the UN Report. “Further to this, damming and extraction have reduced sediment delivery from rivers to many coastal areas, leading to reduced deposits in river deltas and accelerated beach erosion.”

The report also called for reducing demand for sand and gravel through improved designs that cut the amount of concrete in buildings and infrastructure. (Lighter designs would also help address carbon dioxide emissions: Manufacturing cement, the reactive ingredient in concrete, creatives about 5 percent of global carbon dioxide emissions.

UNEP also warns that, “To meet demand in a world of 10 billion people without harming the environment, effective policy, planning, regulation and management will be needed. Currently, sand extraction and use is defined by its local geography and governance context and does not have the same rules, practices and ethics worldwide.” The report aims to start a productive global conversation on sand extraction.

“To curb irresponsible and illegal extraction, ” the report suggests a customization of existing standards and best practices to national circumstances.”

To read or download the full report on sand and sustainability, click here.

Difficulty of Change

Like all large scale transformations, this one will not be smooth or simple. The problem with all such reports is that they apply global observations to local conditions. And local conditions always govern actions and economics. As long as it’s cheaper to mine local sand than import it from Greenland, someone will mine it locally.

Those transportation costs can be a killer. In commodity businesses, every penny saved represents a competitive advantage. When you track that penny through the supply chain to the cost of finished goods ( i.e., to a house, a building, or a street, for example), it can have a substantial impact on affordability.

In a highly competitive, free-market economy like ours, producers will always fight to lower their cost of production. Getting them to voluntarily adopt practices that could benefit society is tough.

We can’t even get sand miners to push back 100 feet from the river. 4,000 miles to Greenland is a bit of a stretch!

That tiny problem aside, the value of reports such as these is that they let us develop alternatives before time runs out.

Posted by Bob Rehak on 7/16/2019

686 Days since Hurricane Harvey

Excavation of Taylor Gully Began Monday

When Barry drifted east over the weekend, it helped the Kingwood Area in more ways than one. Not only did it take flooding rains elsewhere, it allowed Harris County Flood Control to begin maintenance of Taylor Gully on Monday.

Erosion Upstream Clogged Ditch with Sediment

Beginning last year, developers clear cut the area upstream of the Harris County line without sediment control measures in place. That let erosion from the Woodridge Village property (see below) clog Taylor Gully with sediment.

Photo taken after May 7th flood showed massive erosion over large parts of Woodridge Village. Dirt from this area washed through the culvert in the background which had no erosion control measures in place at the time.

Cleaning that sediment out of Taylor Gully will help restore the natural conveyance of the ditch and reduce future flood risk to Harris County residents.

Video courtesy of Jeff Miller. It looks up Taylor Gully toward the Montgomery County Line in the background and then pans downstream toward Rustling Elms. He was standing with his back to Creek Manor. The culvert you see at the start of this shot is the same culvert in the background of the erosion photo above.

Reducing Flood Risk

Approximately 200 homes adjacent to this ditch flooded on May 7th. Residents appreciate every extra margin of safety they can get, especially since Perry homes and its subsidiaries are far from finished with installing detention upstream.

It was less than a week ago that Harris County commissioners accepted the right of way agreement. That allowed flood control to begin this project. Hats off to to the hard and fast working people at HCFCD!

Posted by Bob Rehak on 7/16/2019 with video from Jeff Miller

686 Days since Hurricane Harvey

All thoughts expressed in this post are my opinions on matters of public policy and safety. They are protected by the first amendment of the US Constitution and the Anti-SLAPP statute of the great State of Texas.

Update on Webster, Spurlock Elm Grove Lawsuits; Woodridge Construction

A defendant’s motion to dismiss more than 200 lawsuits brought by two local lawyers, Jason Webster and Kimberly Spurlock, on behalf of flooded Elm Grove residents has been tabled by agreement of the lawyers involved. A hearing on the motion to dismiss was scheduled for Monday, July 15th at 4PM in Harris County Judge Lauren Reeder’s 234th Judicial District Court.

Background: Lawsuits and Motion to Dismiss

Here’s a brief chronology of events in the case to date:

Motion to Consolidate, Change Venue and Counterclaims

That same day (June 17):

On June 24, 2019, the lawyers for both sides agreed to consolidate the cases and Judge Reeder signed an order consolidating them.

On June 27th, the plaintiffs filed a request to enter the defendant’s property to inspect it.

Plaintiffs’ Response to Motion to Dismiss

July 8 – Defendants responded to the plaintiff’s motion to dismiss the case(s). They cited the facts that they were NOT suing LJA Engineers, nor were they alleging any defect in their engineering plans or designs. Their claims, they said, related solely to construction practices. Specifically, they cited:

  • a. Blocking the drainage channels;
  • b. Filling in existing drainage channels;
  • c. Failing to properly install box culverts;
  • d. Failing to create temporary drainage channels;
  • e. Failing to allow adequate drainage after construction;
  • f. Failing to install silt barriers;
  • g. Allowing the Development to force rainfall toward Plaintiffs’ homes;
  • h. Failing to pay proper attention;
  • i. Failing to provide notice or warning; the filling in of creeks
  • j. Failing to have a proper rain event action plan;
  • k. Failing to have a proper storm water pollution prevention plan;
  • l. Failing to follow a proper storm water pollution prevention plan;
  • m. Failing to coordinate activities and/or conduct;
  • n. Failing to supervise the activities of the Development;
  • o. Failing to instruct in proper construction and/or drainage requirements;
  • p. Failing to train in proper construction and/or drainage requirements,
  • q. Failing to construct the emergency release channel; and,
  • r. Failing to timely implement the detention ponds.

On that same day, July 8, Webster and Spurlock filed an amended petition specifying points A-R above.

Lawyers Agree to Table Motion to Dismiss … Subject to Conditions

Last Friday, July 12, the lawyers for both plaintiffs and defendants filed a Rule 11 Agreement. It specifies that Figure Four and PSWA “pass” the scheduled July 15th hearing on the motion to dismiss, but retain their right to refile under certain conditions.

No Rulings Yet on Venue, Access or Trial Date

Judge Reeder has not yet ruled on the change of venue motion or access to the property. Nor has she set a trial date.

Meanwhile, Back at the Construction Site…

Meanwhile, construction on the job site in the last week continued but at a slower pace. According to Elm Grove resident Jeff Miller who has closely monitored construction progress:

  • Rebel Contractors widened a ditch leading down the eastern side of the development adjacent to North Kingwood Forest.
  • They deepened the channel connecting that ditch with the S2 detention pond.
  • The installed culverts under a road that will connect the north and south sides of the project.
  • They continued clearing land, moving dirt and building up portions of the northern section.

Culverts being installed under future road, but not yet functioning
More culverts ready to install under future roads
Future roadway with 3-4 story brush piles in background
More brush piles near future road

No More Obvious Progress on Expansion of Detention Capacity

It appears that no additional detention ponds have yet been excavated beyond S2, according to Miller. Therefore, my last estimate of approximately 25% completion of detention has not changed.

Had Hurricane Barry dropped the kind of water here that it did on Louisiana and Mississippi, Elm Grove and North Kingwood Forest residents would almost surely have flooded again.

LJA Engineers designed the onsite detention to hold a little more than a foot of rainfall. But with only an estimated 25% of the detention functioning at this point, 3″ of water could produce another flood (assuming my estimate is accurate).

Posted by Bob Rehak on July 15, 2019

685 Days since Hurricane Harvey and 9 weeks since May 7

All thoughts expressed in this post represent my opinions on matters of public interest and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas

KHOU Reports Elm Grove and Other Residents Now Eligible for Low-Interest SBA Loans

According to a report by KHOU 11, Harris County Judge Lina Hidalgo announced on Friday that Kingwood residents affected by floods in early May can now apply for SBA loans. Loan amounts can range up to $200,000 with interest rates as low as 1.983 percent. 

Most of those affected live in Elm Grove and North Kingwood Forest. However, the county estimates approximately 400 families in Harris County flooded. They will also be eligible.

Elm Grove on May 9 just south of the clear cut area for the new Perry Homes development in Montgomery County.

Where to Apply

You can get more information about the loans or apply online by clicking here. SBA representatives are also available by calling 1-800-877-8339 or by email at disastercustomerservice@sba.gov.

Harris County, the Texas Division of Emergency Management, the Texas Governor’s Office and the city of Houston worked together to secure the federal assistance.

Hidalgo Stresses Aid May Not Be Available in Next Flood

“We will always fight zealously for our region, but the process for obtaining federal disaster assistance all too often ignores the reality of what’s happening on the ground,” Judge Hidalgo said. “Until the federal government addresses this issue and lowers the threshold for aid, we run the risk in future incidents of hard-hit residents being left without key federal assistance.”

Posted by Bob Rehak on 7/14/2019 with help from Juanita Cantu

684 Days after Hurricane Harvey and 9 weeks after the Elm Grove Flood

What Rivers Looked Like Before the EPA Regulated Water Pollution

Something happened today that made me realize how, as a society, we are losing sight of the things that caused us to regulate the environment 50 years ago. As a result, some bad history could repeat itself

After seeing yesterday’s post about the West Fork mouth bar, a reader named Suzanne Kite sent me a link to an article on BusinessInsider.com. Little did she know that – for me – it would be a free ride on an emotional roller coaster in the wayback machine. The article talked about pollution of America’s rivers before the EPA…and focused on Cleveland, Ohio.

How Physical Landscape Shaped Political Landscape

About two thirds of Americans alive today had not yet been born when Cleveland’s Cuyahoga River caught fire in 1969. So they have no memory of the event that helped give birth to the EPA.

The Cuyahoga River caught fire a total of 13 times dating back to 1868. It was one of the most polluted rivers in America. Photo: Cleveland State University Library.

I remember it vividly. I was born in Cleveland, not far from the Cuyahoga River. Some of my earliest and happiest memories of childhood revolved around clam bakes with my family in Lake Erie in the early 1950s. But then we had to stop. The clams, they said, were contaminated with pollution from the Cuyahoga.

When the Cuyahoga caught fire, it came to symbolize out-of-control pollution. It became the spark that led to the creation of the EPA.

Says Aylin Woodward, author of the BusinessInsider.com article, “The disaster prompted a public outcry that in part led to the formation of the US Environmental Protection Agency (EPA) in 1970. The EPA was charged with regulating the country’s polluted air and waterways…”

“Documerica” Photo Archives

She continued. “Soon after its founding, the agency dispatched 100 photographers to capture the US’ environmental issues as part of a photo project called Documerica. The photographers took about 81,000 images, more than 20,000 of which were archived. At least 15,000 have been digitized by the National Archives, and the images now function as a kind of time capsule…”

The archives actually show many photographs of pollution coming from sand and gravel mines.

If you like looking at old photos, you will find this collection fascinating. This BusinessInsider article shows how people and businesses back then used rivers as sewers. A separate article in the Smithsonian goes into even more detail on the Cuyahoga.

Environmental Degradation Preceded Population Loss

Cleveland was a once-proud and booming city that symbolized America’s industrial might. In 1950, it ranked as the seventh largest city in the country. Houston at the time ranked only 14th with a little more than half of Cleveland’s population. In the latest census (2010), however…

Cleveland ranked 45th and had lost more than half the population it had 60 years earlier. It continues to lose population at an alarming rate.

San Jacinto Problems Not New

An alarming number of readers who saw yesterday’s post about the San Jacinto West Fork mouth bar commented on the massive amount of sediment pollution. They believe that not enough is being done to reduce the amount of sediment coming downstream.

Mouth bar blocking the West Fork of the San Jacinto. Photographed from a drone operated by Franz Willette of BCAeronautics.

Not all, but much of that sediment, in my opinion, came from approximately 20 square miles of sand mines upstream that were inundated by three so-called 500-year storms in 2015, 2016 and 2017. The rate of deposition has increased exponentially as you can see in the graph below.

Sudden exponential growth in mouth bar volume. Graph compiled by RD Kissling from Google Earth historical satellite photos.

FEMA believes that at least 500,000 cubic yards of sediment came downstream during Harvey. The City of Houston believes the number is closer to 1.4 million cubic yards.

All of that sediment pollution threatens the main source of the City’s drinking water by reducing its capacity.

Let’s Learn from History

The point of all this: history is repeating itself.

In 2006, American Rivers named the San Jacinto one of the 10 most endangered rivers in America… because of sand mining. And it has only become worse since then.

These developments make me fearful of the future that my children and grandchildren will inherit. If you share these feelings, please continue to apply pressure on elected representatives to push sand mines further back from the river.

What good is cheap concrete if the environment has become so degraded that people move elsewhere?

Posted by Bob Rehak on 7/13/2019

684 Days since Hurricane Harvey

Weekly Mouth Bar Dredging Update with Images from Carolyn Daniel, Kendall Taft, Franz Willette of BCAeronautics, and the Army Corps

We learned a little bit more this week about the next phase of dredging. Several graphics (below) released by the Corps summarize modifications to the Emergency West Fork Debris Removal Project.

What We Confirmed and Learned

We confirmed that:

  • Great Lakes, the prime contractor on the original job, will be the only contractor on the Corps portion of the contract extension
  • Great Lakes will pump sediment all the way upstream to Placement Area 2
  • The Corps intends to dredge 500,000 cubic yards in the area of the mouth bar.

We learned that:

  • The original contract contingency allotment of approximately $3.5 million was used up, most likely by additional sediment washed downstream during floods in December, January, February, May and June.
  • Callan, the subcontractor for phase one, has approximately 83,000 cubic yards to dredge due to modification of the original contract.
  • Dredging an additional 500,000 cubic yards will cost another $17,085,861
  • The FEMA/Corps portion of the dredging should finish by December 6, 2019
  • Demobilization and cleanup will take until Jan. 22, 2020
  • This is FEMA mission assignment SWD-30
  • Great Lakes started dredging the mouth bar on June 25th
  • Great Lakes will dredge a wide area but not go all the way to the FM1960 bridge.

Corps Releases Summary of Project and Extension(s)

I compiled the information above from a PDF developed by The Army Corps. They released it on July 9.

First page of a 2-page PDF released by the Corps on July 9.
Second page of a 2-page PDF. Army Corps summary of Emergency West Fork Dredging project. For a high-resolution PDF, click here.

To calculate the depth of dredging in that blue area to the right, I simulated the outline in Google Earth and found that it roughly equals 500,000 square yards. That means if they dredge this whole area, they will reduce the river bed by approximately 3 feet. The area already averages 2-3 feet deep. That means the river will be roughly 6 feet deep through this reach when the Corps finishes its portion of the job.

The area outlined by Corps is approximately 500,000 square yards.
Where Callan will finish dredging near Kings Harbor, the depth will be approximately 22.5 feet.

However, upstream, Callan is dredging to a depth of 22.5 feet. Thus, creating a continuous gradient along the river bottom would require dredging approximately another 16 feet deeper in the same area…and that wouldn’t even get you to the FM1960 bridge. Also, note the gap in the graphic between where Callan will finish its portion of Phase One and Great Lakes will start mouth bar dredging.

Unknowns

It is unclear at this point who will dredge the rest of the material that needs to be removed to restore conveyance of the West Fork. Neither the City, County, nor State have yet announced their plans. We don’t know:

  • Where they will dredge
  • How deep they will go
  • Where they will place the material
  • How much it will all cost, or
  • When they plan to do it.

In the meantime, here are two dramatic sequences of photos plus a video submitted by readers this week. They show what the start of mouth bar dredging looked like from the air and water.

Carolyn Daniel Mouth Bar Shots from Airplane Landing at IAH

Carolyn Daniel submitted these shots of the mouth bar and dredging activity taken from her airplane window while on a landing approach to Bush Intercontinental Airport.

On approach to IAH. FM 1960 at bottom of frame. East Fork of San Jacinto upper right and West Fork on the left. Kings Point and Royal Shores between them. Image courtesy of Carolyn Daniel.
Can you spot East End Park? Kingwood Drive? Town Center? All are visible in this shot by Carolyn Daniel.
Mouth bar of west fork with dredge. Photo courtesy of Carolyn Daniel. Note the large Triple-P sand mine near the top of the frame in Porter.
Mouth bar of San Jacinto West Fork with Great Lakes Dredge. Image courtesy of Carolyn Daniel.
Mouth bar of West Fork with dredge. Atascocita Point on left in foreground. Fosters Mill and Kings Point in background. Photo Courtesy of Carolyn Daniel.
Through the clouds. While landing at Bush Intercontinental Airport. Mouth bar of San Jacinto West Fork with Great Lakes Dredge. Image courtesy of Carolyn Daniel.

Franz Willett Drone Shots Courtesy of BCAeronautics

Franz Willette runs a company called BCAeronautics that uses drones in mapping, inspections, roofing analyses, site surveys, and 3D modeling. He did not have clouds to contend with and could shoot safely from a much lower elevation. Willette is FAA certified.

West Fork Mouth Bar with Great Lakes Dredge. Drone image courtesy of Franz Willette, BCAeronautics.
West Fork Mouth Bar with Great Lakes Dredge. Drone image courtesy of Franz Willette, BCAeronautics. Great Lakes should dredge those two small islands in the background.
West Fork Mouth Bar with Great Lakes Dredge. Looking south toward the FM1960 Bridge. Drone image courtesy of Franz Willette, BCAeronautics.
West Fork Mouth Bar with Great Lakes Dredge. Drone image courtesy of Franz Willette, BCAeronautics.

Kendall Taft Video

Video courtesy of Kendall Taft. Shot from south of mouth bar looking north.
Shows how shallow the water is and how vast the expanse is.

I hope to post updates weekly on this project. So readers, please help. Submit your images through the submissions page of this web site. My thanks to Carolyn Daniel, Franz Willette, BCAeronautics and Kendall Taft.

Posted by Bob Rehak on 7/13/2019 with help from Carolyn Daniel, Franz Willette, BCAeronautics and Kendall Taft.

683 Days since Hurricane Harvey

Rehab Work to Begin on Upstream Portion of Taylor Gully Monday, July 15

According to Beth Walters of the Harris County Flood Control District (HCFCD), work on the upstream portion of Taylor Gully in Kingwood will begin on Monday, July 15, weather permitting. There’s still uncertainty regarding the local impact of Tropical Storm Barry, however, equipment has already started showing up at the job site.

Taylor Gully at the county line is half blocked with silt due to erosion from the clearcut area in the Woodridge Village development behind this culvert. Photo courtesy of Jeff Miller.

From Bassingham to Harris County Line

The work will extend from Bassingham to the Harris County line where the Gully meets the new Woodridge Village development in Montgomery County.

Scope of Work

This work will include the following:

  • Desilt the channel
  • Reconstruct the backslope interceptor structures
  • Install new backslope interceptor pipes
  • Regrade backslope swales
  • Install new gates
  • Install new “No Trespassing Signs”
  • Re-Set the covers of the “E type” inlets that have been damaged

Next Steps

After completing this reach of the channel, HCFCD staff will investigate Taylor Gully further downstream, where HCFCD completed a desilt job in the spring of 2019, from Bassingham to the downstream end.  HCFCD will open up any constrictions and desilt the channel if necessary.

Vital for Flood Mitigation

Approximately 200 homes near this channel flooded during the May 7th storm. According to residents, video taken during the storm, and still photos taken after the storm, overland sheet flow from Woodridge Village was the likely cause of their problems. Regardless, news of this effort will come as a great relief to Elm Grove and Woodstream residents who welcome every extra margin of safety they can get.

Kudos to the flood control district for jumping on this project. Commissioners Court approved the right of way acquisition only last Tuesday!

Work on Montgomery County Portion of Gully Also Proceeding

Elm Grove resident Jeff Miller also reported today that Woodridge has expanded a portion of Taylor Gully that runs through Montgomery County. Where the east/west portion of the ditch makes a 120 degree turn and starts heading south along the western border of North Kingwood Forest…

This corner and the portion of the ditch that extends straight down were expanded this week.

… the contractor widened the ditch and expanded the turn.

Dozens of homes flooded in North Kingwood Forest (left side of photo behind tree line) on May 7. This ditch had a tiny portion of current capacity at the time (see below). Photo courtesy of Jeff Miller.

For comparison, here is what the same ditch looked like on May 12.

Same ditch as above adjacent to North Kingwood Forest (on left) but on May 12.

To see what the entire turning radius NOW looks like, see this video.

Video courtesy of Jeff Miller.

More good and welcome improvements. Just wish they had been in place before May 7th.

Posted by Bob Rehak on 7/13/2019 with help from Jeff Miller.

683 Days after Hurricane Harvey and Two Months after the Elm Grove Flood

Christmas in July for Elaine Phillips

It wasn’t supposed to happen. But it did. After receiving two letters and two visits telling Elaine Phillips that the City could do nothing to fix her drainage, trucks magically showed up this morning … and fixed it. They gave her no explanation.

Epic Battle over Partially Blocked Drainage Swale

You may remember me posting about Elaine Phillips on June 21. Elaine was battling cancer, contractors, and the City of Houston bureaucracy all by herself. Her home had just flooded for the fifth time since 1997 and her husband was working in New York. The swale in front of her home had never been regraded and was partially clogged with sediment.

Surprise Turn of Events

“We had been told, as recently as Wednesday, 7/10, that nothing would be done in the near future, despite the unrelenting efforts of both Dave Martin’s office and Dan Crenshaw’s office,” said Elaine. “Then I woke up to four city trucks and a back hoe Thursday morning. They regraded the ditches from my house to the corner and Cindy’s house to the corner. Don’t know how, who, or why it’s happening, but I’m not going to look a gift-horse in the mouth. It’s Christmas in July! Many thanks to Kaaren Cambio from Dan Crenshaw’s office and Dave Martin’s office as well!”

Elaine Phillips newly graded ditch should help ensure positive drainage in future storms and move water away from her house faster.

Altogether, Phillips estimates that various city, county, and congressional representatives worked dozens of hours trying to help her for a job that ultimately took about five hours from start to finish.

Other Possibilities Still Remain

Phillips has also explored elevating her house and buyouts. Both remain possibilities thanks to their extra efforts on her behalf.

In the meantime, Phillips is giddy with glee. Until today, progress had remained elusive for 22 years.

For good measure, and in the spirit of Christmas, while the City of Houston crew was out helping Phillips today, they also deepened the ditches in four more homes near the same intersection.

A hearty thanks to the City from the Kings Forest Board and residents.

Posted by Bob Rehak on July 12, 2019

682 Days since Hurricane Harvey


Latest Barry Update and How to Interpret a Cone Map

There’s a lot more in a cone map than meets the eye. The map below shows the latest forecast track for Tropical Storm Barry. Here’s a short tutorial on some other things you can get out of it.

Status of Tropical Storm Barry as of 1PM CDT, Friday July 12, 2019

As you can see, the trajectory continues to favor landfall in Louisiana and then movement up through Arkansas. However, these maps convey much more information that may not be apparent at first glance.

What Cone Map Symbols Mean

This graphic shows an approximate representation of coastal areas under a hurricane warning (red), hurricane watch (pink), tropical storm warning (blue) and tropical storm watch (yellow).

The orange circle indicates the current position of the center of the tropical cyclone.

The black line, when selected, and dots show the National Hurricane Center (NHC) forecast track of the center at the times indicated.

The dot indicating the forecast center location will be black if the cyclone is forecast to be tropical and will be white with a black outline if the cyclone is forecast to be extratropical.

If only an L is displayed, then the system is forecast to be a remnant low. The letter inside the dot indicates the NHC’s forecast intensity for that time: 

D: Tropical Depression – wind speed less than 39 MPH
S: Tropical Storm – wind speed between 39 MPH and 73 MPH
H: Hurricane – wind speed between 74 MPH and 110 MPH
M: Major Hurricane – wind speed greater than 110 MPH

Forecasting Uncertainty

NHC tropical cyclone forecast tracks can be in error. This forecast uncertainty is conveyed by the track forecast “cone”, the solid white and stippled white areas in the cone map graphic.

The solid white area depicts the track forecast uncertainty for days 1-3 of the forecast, while the stippled area depicts the uncertainty on days 4-5.

Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. So about 2 out of 3 times.

How the NHC Forms Cone Maps

To form the cone, a set of imaginary circles are placed along the forecast track at the 12, 24, 36, 48, 72, 96, and 120 h positions, where the size of each circle is set so that it encloses 67% of the previous five years official forecast errors. The cone is then formed by smoothly connecting the area swept out by the set of circles.

Big Difference Between Cone Size and Storm Size

Realize also that a tropical cyclone is not a point. Their effects can span many hundreds of miles from the center.

The area experiencing hurricane force (one-minute average wind speeds of at least 74 mph) and tropical storm force (one-minute average wind speeds of 39-73 mph) winds can extend well beyond the white areas shown enclosing the most likely track area of the center.

Other Linked Graphics Complete the Story

The distribution of hurricane and tropical storm force winds in this tropical cyclone can be seen in this linked Wind History graphic.

Considering the combined forecast uncertainties in track, intensity, and size, the chances that any particular location will experience winds of 34 kt (tropical storm force), 50 kt, or 64 kt (hurricane force) from this tropical cyclone are presented in tabular form for selected locations and forecast positions. This information is also presented in graphical form for the 34 kt50 kt, and 64 kt thresholds.

All things considered, the latest forecast shows that there’s only a 5% chance that Houston will see tropical storm force winds from this event.

If you have relatives or friends living closer to the center of the projected path, the tabular data above, will show you the exact percentages for dozens of cities.

To Find the Latest Cone Maps

Go to the National Hurricane Center and click on two-day or five-day. Then scroll to the bottom of the page for many linked graphics that tell the story of the storm.

Rainfall Graphic

Latest rainfall map projects that Houston may get up to an inch of rain, while parts of Louisiana are getting more than 16 inches.

Posted by Bob Rehak with Info from the National Hurricane Center on July 12, 2019

682 Days since Hurricane Harvey

Fault Movement and Property Damage Linked to Aquifer Depletion in Montgomery County

A new report just released by the SMU Department of Earth Sciences draws several important conclusions that bear on the groundwater management debate in Montgomery County. The report links aquifer depletion and subsidence with fault movement, road damage, home damage, and damage to other structures.

Subsidence in the north Houston/Montgomery County region from a separate report by the HGAC.

Aquifer Depletion Linked to Fault Activation/Property Damage

Significant findings include:

  • Excessive groundwater production has resulted in water-level declines, subsidence, and fault movement.
  • Subsidence and fault movement are not just limited to the Evangeline aquifer; they also occur in the Jasper aquifer.
  • Fault movement has damaged roads, highways, homes, wells, pipelines, and other surface structures.
  • Timing and location of fault movement correlates to timing and location of water-level declines and subsidence.
  • Damages from fault movement go beyond The Woodlands area. They extend as far north as the Conroe Aquatics Center near downtown Conroe.

Peer Reviewed Research Funded by NASA and SMU

NASA and SMU co-funded the peer reviewed research which appeared in the June 25, 2019, issue of the journal Remote Sensing.

Some key quotes:

“Hundreds of paved roads and homes in the Houston area are being offset by faults and require frequent maintenance.”  (p. 1)

“The newly discovered fault activation appears to be related to excessive groundwater exploitation from the Jasper aquifer in Montgomery County.  The continuous mining of groundwater from the Jasper aquifer formed new water-level decline cones over Montgomery County, corroborating the intensity of new fractures.” (p. 1)

“Our study seems to validate that subsidence and related shallow subsurface fault activities in northern [Greater Houston] relates to mining of aquifers.” (p. 17)

“Faulting activities were in connection with the spatial distribution and density of water-level decline and ground subsidence.”  (p. 16)

“…the newly discovered fault activation appears to be related to the stress associated with fluid pressure reductions caused by excessive water extraction from Montgomery County aquifers.” (pp. 17-18)

Corroborates Other Research

The results of this SMU report further corroborate recent findings published by the Harris-Galveston Subsidence District in May, 2018. The subsidence district concluded that the Jasper aquifer is compressible and that the potential for subsidence increases in the northern portions of the Jasper where it is being used for freshwater supply.  

For Full Report

For the full report, see: Qu, F.; Lu, Z.; Kim, J.-W.; Zheng, W. Identify and Monitor Growth Faulting Using InSAR over Northern Greater Houston, Texas, USA. Remote Sensing. 201911, 1498.

Need for Full-Cost Accounting

Last year, I observed that we should have full cost accounting for sand mining along the river. If we had such a thing, sand mining practices might be different. The same could be said for groundwater pumping. As a famous oil-filter commercial once said, “You can pay me now or pay me later.” Yet another Montgomery County mystery to ponder.

Posted by Bob Rehak on 7/12/2019

682 Days since Hurricane Harvey