Tag Archive for: BMPs

Mining Technology Feature Article about Sand Mining in the Wake of Hurricane Harvey

A lady named Molly Lempriere from Mining Technology magazine (a Global Data publication) contacted me from the UK for an interview. She said she was “writing an article about the effect of sand mining in the wake of Hurricane Harvey and its impact on flooding.”

These were the questions she asked and my responses. Since most of you don’t read Mining Technology, I wanted to share them with you. Her article has not yet appeared and may not. She has not responded to my queries about its publication date.

When we experience a disaster like Harvey, it’s important to examine all the factors that contributed to the damage, and mitigate each to the extent possible.

Q. How long have you been campaigning against sand mining?

A. I’m not campaigning against sand mining per se. I’m campaigning against reckless sand mining. I began in September 2017, when it became apparent that giant sand deposits left by Hurricane Harvey contributed to billions of dollars in damages in my area.

Q. How devastating was Hurricane Harvey to the surrounding area?
  • FEMA (Federal Emergency Management Agency) received more than 16,000 claims from residents and 3,300 from businesses in the Lake Houston area.
  • Harris County Flood Control documented more than 5,500 damaged structures in the Humble and Kingwood areas alone. Note: One structure, such as an apartment complex, might include hundreds of people.
  • At least ten people (that I know of) died.
  • After 11 months, only half of the residents who flooded are fully back in their homes.
  • City of Houston estimates Lake Houston area damages to be in the billions.
  • City of Houston estimates this area’s tax revenues were reduced 20-30 percent.
  • Our local school district documented $97.5 million in damages to its facilities so far; two still have not re-opened.
  • Kingwood High School closed for 7 months; 4000 students had to be bused to another high school more than an hour away the entire time.
  • U.S. Army Corps of Engineers will begin an emergency $70 million dredging project this week.
  • 44 percent of all Lake Houston Area Chamber of Commerce businesses were adversely affected (100% within certain areas up to 1.5 miles from the San Jacinto River).
  • Union Pacific Railroad had to replace its bridge, disrupting rail traffic for weeks.
  • TxDoT had to replace part of the I-69 bridge for more than $20 million. All traffic in and out of Houston was delayed for months.
  • A new hospital facility is still under repair after 11 months.
  • Lone Star College lost 6 of its 9 buildings in Kingwood for most of the school year and won’t be fully operational until 2019.
  • Kingwood’s library closed for more than eight months.
  • Two local parks were inundated with sand; some dunes exceed 10 feet in height.

 

Harvey knocked out the Union Pacific Railroad bridge over the San Jacinto River near I-69. It disrupted rail traffic for weeks. Picture taken 9/14/2017.

 

TxDoT had to replace the I-69 southbound bridge at a cost of more than $20 million. The bridge re-opened in July, 2018.

Q. Were the effects of sand mining on flooding considered previously?

A. Yes.

  • State Representative Dan Huberty introduced legislation in 2011 to regulate sand mines due to concerns about the increasing rate of sedimentation.
  • Former State Senator Tommy Williams introduced legislation to tighten restrictions on sand mining near rivers. TACA lobbied against it and it failed.
  • Prior to that, Texas implemented a pilot program for a small portion of the Brazos river that restricted sand mining within the 100-year flood plain.
  • Lake Houston, the main source of drinking water for America’s fourth largest city, is losing capacity at an increasing rate– even as the City plans to supply another 1.5 million customers with water from the lake.
  • Area around Kingwood’s only boat launch has required dredging at an increasing rate.
Q. To what extent are sand mines directly to blame?

A. Asking the question this way is like asking what percentage of a train wreck was due to poor visibility, excessive speed, tight curves, or a tired engineer. It’s impossible to quantify.

However, sand miners deserve part of the blame. They contributed to the problem by pushing the safety envelope. They built mines in floodways, lobbied against common sense regulations that could have minimized damage, and ignored best practices commonly observed in other states that reduce erosion.

Certainly, not all sand mines share equally in the blame; some operate more responsibly than others. Certainly, part of the sand comes from natural sources. And certainly, Mother Nature pushed the limits with Harvey.

However, TACA wants people to believe that no sand came from mines because of the way they are designed.

Aerial and satellite imagery show the TACA claims to be misleading. See:

With one exception, all area sand mines have chosen to locate, at least partially, in floodways. Some are entirely in floodways. That means they are in the main current of the river during floods. At the peak of Harvey, that current carried approximately 150,000 cubic feet per second down the West Fork of the San Jacinto River where miners had exposed almost 20 square miles of sand IN THE FLOODWAY.

One mine, whose dikes have repeatedly broken, leaves only 40 feet of unvegetated sandy buffer between operations and the river. Its dikes are not sloped like best management practices recommend.

As a consequence of ignoring best management practices for setbacks, buffer zones, slopes, and vegetative erosion controls, the dikes in that mine have broken repeatedly. Floodwaters go over and through its dikes, washing sand downstream.

That sand then constricts the carrying capacity of the river, reduces the river’s gradient, and blocks drainage ditches. In these ways, sand mines contribute directly to flooding.

TACA has fought legislation that: prohibits mining in these dangerous areas, leaves natural buffers against flooding, and makes miners responsible for cleanup.

Q. What more needs to be done to protect the local area against sand mining?

A. Several things.

  • If all sand mines followed best management practices commonly used in other states for setbacks, erosion controls, buffer zones, vegetation, reclamation, and construction, I believe we could radically reduce the amount of sand coming from mines during floods.
  • Mining in floodways should be outlawed. It’s reckless. It has also proven dangerous, and harmful.
  • When dikes are breached, owners should promptly repair them. In one case, a broken dike has gone unrepaired for three years while the mine emits sand and sediment directly into the San Jacinto River. In another case, a dike went unrepaired for eight years.
  • Sand miners should acknowledge that they are part of the problem instead of denying it. They should post remediation and cleanup bonds rather than externalizing their cleanup costs to downstream residents.

A mine whose dikes were breached and remained open for eight years was repeatedly flooded. 

Q. On ReduceFlooding.com you mention that there are multiple agencies with conflicting mandates that govern the river. So is it the mining that’s inherently bad or the management?

A. This question belies TACA’s role in aggressively lobbying against common-sense regulations that would protect residents.

Conflicting mandates have nothing to do with bad management; they’re about focus. Only one agency focuses on flood control. Others focus on conserving and selling water.

Q. Are there lessons that could be learned from other sand mining operations around the world?

A. Yes. If Texas sand miners followed the best management practices (BMPs) from other states and countries, many of the problems here could be reduced or eliminated.

Communication of BMPs also needs to be improved. Louisiana has an excellent guide to best management practices for sand mining. It’s clear, concise, candid, well written and well illustrated. It was developed by government and industry working together, and clearly lays out the dangers if best practices are not followed.

Alaska discourages mining within 1000 feet of a public water source. That could help here. The San Jacinto River is the main source of water for millions of people.

Q. Is there a way for TACA and sand mining to help reduce flooding risks?

A. Yes.

  • Don’t locate sand mines in floodways.
  • Follow best management practices used in other states and countries.
  • Quit misleading people, especially legislators.
  • Acknowledge the risks and dangers; quit pretending they don’t exist.

During Harvey, when the San Jacinto River Authority had to open the floodgates on Lake Conroe, approximately 150,000 cubic feet per second swept through 20 square miles of sand mines.

Partially as a result, one particular sand dune that the Army Corps of Engineers expects to begin dredging next week grew 1,500 feet in length and 12 feet in height in one day during Harvey. It completely blocked a drainage ditch that empties the western third of Kingwood. More than 650 homes and a high school that depend on that ditch flooded. Result: more than $250 million dollars in damages. Did all of that sand come from mines? No. Did mines contribute? Yes.

Q. What ideally would you like to happen next? 

A. We need to:

  1. Stop sand mining in the floodway of the main drinking water source for America’s fourth largest city.
  2. Establish minimum setbacks between mines and rivers, especially the San Jacinto.
  3. Create a clear, concise set of best management practices (BMPs) that everyone can read and understand.
  4. Raise awareness of BMPs.
  5. Follow BMPs.
  6. Increase fines for those who fail to follow BMPs.
  7. Remediate abandoned mines.
  8. Within active mines, immediately re-vegetate areas that are no longer being actively mined.

All but one of the West Fork mining operations are not only in the floodplain, they are in the FLOODWAY! The Red cross-hatched areas above show the floodway, while the Aqua shows the 100-year flood plain.

Q. Is there anything else that you’d like to add?

A. I contacted TACA. They did not respond to me.

Posted 8/5/2018 by Bob Rehak

341 Days since Hurricane Harvey
 

Do Local Sand Mines Follow Best Management Practices?

Note: This is the first article in a series on sand mine best management practices. It focuses on insufficient natural buffers between the mines and the San Jacinto river. Subsequent posts will focus on land clearing, site reclamation practices, and more.

A comparison of sand mining actual and best management practices found that performance shortfalls in local mines exacerbate sedimentation in the San Jacinto River, contrary to assertions by the Texas Aggregate and Concrete Association (TACA) that sand mining has environmental benefits.

Proximity of mines to San Jacinto River in non-flood conditions.

TACA claims that when a river floods, the current is so weak that sand and sediment are deposited inside of mines. An analysis of satellite and aerial photos shows, though, that the current is strong enough to break dikes, destroy roads, re-route the river through mines, and carry sediment downstream.

TACA sounds eerily reminiscent of Richard Pryor when his wife caught him in bed with another woman. “Who you going to believe? Me or your lyin’ eyes?”

In at least one case, a broken dike has gone unrepaired for years while pollution continues to escape into the San Jacinto, the main source of water for Lake Houston and millions of people.

Dangers of Sand Mining

Numerous states and countries acknowledge the following risks of sand mining. Most impose regulations on the industry because sand and silt washed downstream from mines can:

  • Impair water quality
  • Increase water treatment costs
  • Impair wildlife and fish habitat
  • Reduce carrying capacity of rivers and streams
  • Reduce the volume of lakes
  • Block drainage ditches
  • Contribute to flooding
  • Impose dredging expenses on taxpayers
  • Ruin recreation

Louisiana: Leader in Communicating Best Practices

The Louisiana Best Management Practices Guide to sand mining is one of the most concise, candid and clearly written guides in the world. Government and industry developed it together. The refreshingly honest introduction states:

  • “Sand and gravel mining operations can potentially cause off-site impacts to water quality if site planning and BMPs are not factored into every aspect of the mining operation.”
  • “…BMPs … should be utilized … to prevent pollutants from leaving the mining operation.”
  • “Siltation is considered the highest nonpoint source priority of concern in wetland areas and the second highest priority affecting lakes (1992 Report to Congress).”
  • “Mining related activities have been estimated to cause 7 percent of the nation’s nonpoint source impacts to lakes and 17 percent to coastal waters.”

Comparing Texas Practices to Other Areas’

Texas does not make it clear what the state’s best management practices (BMPs) for sand mines are. So how do sand mines along the San Jacinto measure up to other states’ and countries’ guidelines? Not well.

One focus of their BMPs is the use of buffer zones, setbacks and strips of vegetation to reduce erosion and control sedimentation. The minimum distance between mine and river in most cases is 100 feet. Some specify more.

  • Alaska, for instance, discourages mines from locating within 1000 feet of a public water source, i.e., the San Jacinto which feeds Lake Houston, the main drinking water source for millions of people. The minimum near other bodies of water in Alaska is 200 feet.
  • Malaysia specifies a 50 meter setback (164 feet) from all river channels.
  • Australia prohibits sand mining in sensitive areas altogether.

In Texas along the San Jacinto, miners often excavate to within 40-50 feet of rivers, and remove vegetation to build dirt roads on the remaining narrow strip between the mine and the river. These thin, sandy barriers provide little defense against floods. They have been repeatedly breached, as you will see below. The river often runs right through mines, carrying sand and sediment downstream.

Types of Barriers against Sedimentation

Louisiana mandates a minimum 100-foot buffer adjacent to perennial streams. The state recommends a dual defense against sedimentation: vegetation and structural measures. Their best practices guide states, “Vegetation is an inexpensive and effective way to protect soil from erosion. It also decreases erosion from flowing water by reducing its velocity. Roots hold soil and increase infiltration. Topsoil should be added where existing soils are not suitable for adequate vegetative growth.”

Vegetative controls include:

  • Maintaining buffer zones between mine and river
  • Sod stabilization techniques. Sodding can be more than 99 percent effective in reducing erosion.
  • Protection of trees involves preserving and protecting selected trees that exist on the site prior to development.
  • Temporary and permanent seeding

Structural controls include:

  • Diversion ridges, berms or channels of stabilized soil
  • Silt fences
  • Sediment basins with banks sloped at 2:1 or less
  • Dikes – Must be well compacted and vegetated, with an outlet pipe or coarse aggregate spillway
  • Riprap protection – at the outlet end of culverts or channels to reduce the depth, velocity and energy of water so that the flow will not erode the receiving stream.
  • Check dams – Small dams less than 2 feet high constructed across swales or drainage ditches to reduce flow velocity and erosion.
  • Aggregate stabilized site entrances – at least 50 feet long to reduce sediment tracked onto public roads. Tire washing may also be needed.
  • Good housekeeping practices for fuel, debris, sediment from unstabilized areas, etc.
  • Post-construction stormwater management measures
  • Retention ponds
  • Vegetated swales and natural depressions that filter sediments from runoff with side slopes of 4:1 or less.

A Visual Comparison

Note the images below. The first represents the ideal; it is taken from the Louisiana BMP guide. The rest are from the West Fork of the San Jacinto in the last three years.

Image of ideal stream bank from Louisiana Sand Mining Best Practices Guide. Note vegetation, grass, gradual slope and aquatic plants.

West Fork Sand Mine,  9/14/2018. During Harvey, 150,000 cubic feet per second came rushing down this narrow channel and flooded 20 square miles of exposed sand in more than a dozen different mines.

Consequences of NOT Following BMPs

The image above and the following images all come from a small area of investigation shown below.

2.1 miles from Northpark Drive and US59, and 3.1 miles upstream from the US59 bridge.

The following images demonstrate what happens when miners work too close to the river. Numbers on the first image correspond to close-ups that follow.

Inundation of sand mines during Harvey on 8/30/17. Numbers correspond to close-ups below.  All photos courtesy of Google Earth.

1 – Rapids within sand mine.

2 – Water rushing into mine, creating turbulence.

3 – Water takes a shortcut across meander through mine.

4 – Washed out road INSIDE sand mine during Harvey. 

5 -Sand bars within sand mine in conjunction with ruptured dikes prove sand was carried downstream. Photo taken on 10/28/2017 (after Harvey).

In a white paper circulated among Texas state legislators called The Societal and Environmental Benefits of Sand Mining. TACA insists, “When [water invades a sand mine during a flood], the velocity of the water slows significantly, losing its ability to keep sediments in suspension and the stream or river begins to deposit its sediment load. When flood waters back into an area where a sand and gravel pit is located, the pit becomes a sediment trap for the flood waters and their sediments.” This series of photos directly refute TACA’s claims.

Why do we allow sand mines to operate in areas that flood repeatedly and violently, so near the drinking water source for millions of people?

Un-repaired Dike Still Leaks Sediment after 3 Years

Are the mines following Best Management Practices? The dike on the right in the images below ruptured in 2015 and still has not been repaired. Note sediment streaming into the West Fork.

Dike ruptured during flood in 2015 (see image below). It continues to spew sediment into the river.

Geologists say that once a river “captures” a sand mine, it repeatedly tries to take that same route in subsequent floods. This is a direct consequence of mining too close to the river. 

Cautionary Advice from India

Sustainable Sand Mining Management Guidelines from India state, “Floodplain Extraction should be set back from the Main Channel. In a dynamic alluvial system, it is not uncommon for meanders to migrate across a floodplain. In areas where sand and gravel occurs on floodplains or terraces, there is a potential for the river channel to migrate toward the pit. If the river erodes through the area left between the excavated pit and the river, there is a potential for “river capture,” a situation where the low-flow channel is diverted though the pit. In order to avoid river capture, excavation pits should be set back from the river to provide a buffer, and should be designed to withstand the 100-year flood… Adequate buffer widths and reduced pit slope gradients are preferred over engineered structures which require maintenance in perpetuity.”

Sand Miners Externalize Costs

Because these West Fork sand mines did not consider violent floods in their design and construction criteria, taxpayers downstream bear the cost of remediation. Dredging of the West Fork will cost tens of millions of dollars – for the initial 2.1 mile phase alone! That doesn’t even include recurring and unnecessarily high costs of water treatment because of turbidity.

Posted 6/24/18 by Bob Rehak

299 days since Hurricane Harvey