Tag Archive for: U.S. Army Corps of Engineers

Dredging Status: End of September

The U.S. Army Corps of Engineers has spread out across the West Fork of the San Jacinto River for its Emergency Dredging Project. Here is a visual status report from a trip up the river on Friday. I went from West Lake Houston Parkway past the US59 bridge to chronicle what has become an amphibious construction project.

The first dredge belonging to Callan Marine, a subcontractor to Great Lakes Dredge and Dock, has taken up position near the high tension power lines that connect Kingwood and Kings Lake Estates.

This is what the entire dredging assembly looks like.

It has been idling in the same position more than a week while pipeline and booster pumps are connected to it upstream.

Here’s what it looks like from the stern where dredged materials will enter the pipeline that takes them back to placement area #1.

This booster pump is required because of the distance to placement area #1 behind the apartments on Townsend near North Houston Avenue just south of the river.

Pilot boat shuttles pontoon with heavy equipment into place.

Heading upriver, more pipeline waits to be connected near the dredging command site.

At the command site, staff scurries to get the second dredge ready to launch before mid-October.

Dredge #2 owned by Great Lakes Dredge and Dock. This electric dredge will pump sediment to placement area #2 and require more booster pumps than the first dredge because of the length of the pipeline, almost five miles. Placement area #2 is on Sorters Road just south of Kingwood College.

Close up of the business end of the second dredge still at the dock. The rotating assembly stirs up sediment which is then suctioned into the pipeline and pumped to a placement area.Workers loading water into pipeline to get it to submerge. 

Pontoon with crane and pipeline welding equipment.  Sections of pipe waiting to be connected provide a convenient resting place for egrets and other water fowl.

The debris barges will offload their cargo here, where it will be transferred into these trucks and hauled away for processing or landfill.

Meanwhile, another crew scouts a route to placement area #2. Up the West Fork near Kingwood College, the river is so shallow, it may not be deep enough to float pipeline. If dredging in this reach of the river becomes necessary, it could delay the job and increase costs.

From this brief visual trip up the river, you can see that much prep work remains before full dredging can start. The second dredge has not yet launched and no pipeline has reached placement area 2. City officials have stated that the Corps hoped to be in full operation by mid-October. The 270-day clock for this project began ticking on August 19. Two hundred and twenty-nine days remain to the expected completion. Before the project is done, the Corps expected to move 1.8 million cubic yards of sand and sediment out of the river. 

Posted by Bob Rehak on September 30, 2018

397 Days since Hurricane Harvey


Dredging Update: First Dredge Being Assembled, Miles of Pipe Being Welded

The U.S. Army Corps of Engineers’ Command Site for its San Jacinto West Fork Emergency Dredging Project is a beehive of construction activity. I spent two hours at the site this morning at the invitation of the Corps. Now I can see why the prep is taking as long as it is. I had no idea so much was involved. Last week, I posted pictures of dozens of trucks arriving with equipment and pipe. This week they are assembling the first dredge of two and welding miles of dredge pipe…even as more arrives every hour.

First of Two Dredges Nearing Completion

Because of their size, two dredges are being delivered to the site in pieces and assembled there. Great Lakes Dredge and Dock, the contractor, brought in a 300-ton crane last week to lift the biggest pieces to the water’s edge. At the moment, two smaller 70-ton cranes are completing the work – lifting pumps, motors, stabilizers and other equipment into place.

Two seventy-ton cranes lift the remaining pieces of the first dredge into place at the command post south of the river.

Worker installing safety rails.

Same dredge showing where the dredge pipe will hook in.

Massive fittings weigh thousands of pounds

More dredge pipe arrives as the first dredge nears completion.

One of the impellers that will force dredged material into the dredge pipe. These are bigger than the pallet they sit on and are made from solid steel. They are actually considered a disposable item in the dredging process because they wear out. They are  the rotor located inside the case of a pump. it increases or decreases the pressure and flow rate of a fluid. 

Miles of Dredge Pipe Being Welded and Weighted

As workers assemble the first dredge near the water’s edge, other workers weld miles of dredge pipe together from 40-foot sections in a separate staging area. Each section weighs about 4,000 pounds. And each string is 1,000 feet long – about a fifth of a mile. These longer sections will then be put together with booster pumps to pipe spoils directly from the river to placement areas.

Acres of 24-inch HDPE pipe have arrived at the job site and are being stored in a massive pipe farm. Walls of the pipe are one inch thick. Each 40-foot section weighs about 4000 pounds.

Already five larger 1000-foot sections have been assembled. That’s nearly a mile of dredge pipe.

Welding machine shaves off the end of each pipe so the joints will be clean and even.

Next the welding machine heats up the ends of each pipe to 450 degrees and fuses them into one continuous piece.

This is what a completed weld looks like. It’s as strong as the pipe itself.

Next the pipe will be weighted with these steel collars to make sure it remains submerged during dredging operations. This is important because one pump might stop temporarily during dredging while other pumps continue to pull water through. The now partially filled pipe could become buoyant and a hazard to navigation.

To attach the collars, first, two halves are chained together then sledge-hammered into place.

Then the halves are welded together to form a permanent bond. This process is repeated over and over hundreds of times until each 40-foot section has its own collar/weight. The black screen is a safety device to protect the eyes of people nearby who may not have welding goggles. The flame from welding can be as intense as looking directly into the sun. 

Safety Warning

Do not attempt to visit this site. Stay away for your own safety. Huge construction equipment is moving about the site. Operators have limited visibility and they’re focused on balancing their loads, not looking out for unauthorized visitors.

Actual dredging should start in about ten days. When it does, it won’t be safe to be in a boat between the US59 and the West Lake Houston Park Bridges.

The pipe you see above will be submerged and marked with these buoys.

Safety buoys mean submerged dredge pipe is in the area. Stay away for your own safety. Do not attempt to boat, water ski, fish, or swim in the vicinity of dredging operations. Pipe can move swiftly and without warning. 

Dredging operations will continue 24/7 until completion. There is no safe time of day or day of the week to be in this section of the river.

Pipe will extend from wherever the current dredging is to one of two placement areas. One is south of Kingwood College and the other is between the river and Townsend east of US59.

Posted on August 20, 2018 by Bob Rehak

356 Days since Hurricane Harvey

Mobilization in Full Swing For Army Corps Dredging Project

The countdown has begun to D-Day – Dredging Day. D-Day is still a month away, but things are changing on the ground. Finally. Mobilization has begun for the U.S. Army Corps of Engineers Emergency Dredging Project on the West Fork of the San Jacinto.

During the last week, the winning bidder has been out surveying the lake, planning the job, and ordering equipment and materials. Now the hard work has started.

Roads are being built to the staging area. Equipment is being installed. Pipeline is being laid. For all those who doubted this day would ever come, here are the pictures that prove it’s happening.

Building a road to the launch site. All photos courtesy of the US Army Corps of Engineers

Grading the road.

Dock area shaping up.

Containers and heavy equipment arriving.

Generators in tow.

Heavy equipment and dredge pipe.

What to Expect When

Right now, crews are setting up the staging area. This week, pipeline arrives and crews will begin installing it. By August 18, two dredges will arrive in pieces by truck. Crews will then begin assembling and launching them.

On August 20, general debris removal will begin. By September 1, the dredges should be sucking sand out of the river and pumping it into placement sites. That process will continue until next April.

Phase Two?

At that point, unless funding has been approved to extend the dredging to include the mouth bar, the contractor, Great Lakes Dredge and Dock will begin removing its equipment from the river and cleaning up after themselves.

The cost of mobilization and demobilization – $17,900,000 out of approximately $69,800,000 – represents almost exactly 25% of the contract. The time also represents about 25% of the total time allotted.

For Your Own Safety…

For safety reasons, the Army Corps respectfully requests the public to stay away from the staging area. The amount of heavy equipment in use and the fast pace of work make this important. The Corps is not publishing details of the staging area’s location, though that will soon become apparent due to the increase in traffic. Just remember, these people have a large job to do and little time to do it. Please respect the demands on their time and respect the perimeter of the job site for your own safety. In the next eight months, they will move enough sand to fill up the Astrodome and then some.

Posted by Bob Rehak on July 31, 2018

336 Days since Hurricane Harvey

Seasonal Lowering of Lake Conroe Begins August 1

On August 1, the City of Houston Public Works Department, the San Jacinto River Authority (SJRA) and the Coastal Water Authority (CWA) plan to begin lowering the level of Lake Conroe as part of a joint operations plan to mitigate flooding threats during the peak of hurricane season. The plan calls for lowering Lake Conroe gradually through small releases – about an inch a day – until the lake level reaches 199 msl (mean feet above sea level).

Intent of gradual lowering of Lake Conroe is to avoid another 79,000 cubic-feet-per-second release rate as we experienced during Harvey. Until normal flow is restored to the West Fork, Lake Conroe will be lowered temporarily and seasonally to mitigate flood risk.

Lake Conroe to Be Lowered 2 Feet Through September

This initial lowering will last through the end of September to create additional storage in Lake Conroe which could delay releases and minimize release rates during a storm, thereby providing a buffer against flooding for residents who live downstream of the dam.

The next lowering would occur during the peak of the spring rainy season – from April 1 – May 31, 2019. However, that lowering would only be by a foot – to 200 msl, because the rain threat is usually lower in spring.

Only Until Dredging Restores River’s Flow

The joint operations plan calls for continuing to lower Lake Conroe seasonally in this manner while the U.S. Army Corps of Engineers dredges the West Fork of the San Jacinto to restore flow.

Hurricane Harvey deposited tremendous amounts of silt in the West Fork which  physically changed the river’s ability to safely pass water during storms. Hence, the dredging.

Phase-One Dredging Has Already Started

Phase one will go from River Grove Park to the West Lake Houston Parkway bridge. Great Lakes, the contractor hired by the Corps, has 269 more days to complete the initial phase.

Phase-Two Still Needs Funding

The total project could take longer. Community leaders are now working furiously to arrange funding to dredge the remainder of the west fork, including the mouth bar.

Mobilization and demobilization comprise 25 percent of the total phase one project costs (approximately $18 million out of almost $70 million). Having phase two ready to start before phase one ends could save that money, creating extra value for taxpayers and enabling even more dredging, say for instance, on the East Fork.

Temporary Lake Conroe Lowering Could Last Up to 3 Years

The City, SJRA, and CWA will continue the seasonal lowerings for up to three three years. They will monitor progress of the dredging and annually re-evaluate the need to lower Lake Conroe. If the river’s flow is restored before three years, the temporary lowering would cease.

Lakes will Operate under Two Different Strategies

Lake Conroe is located upstream from Lake Houston. Large pre-releases immediately before a storm run the risk of pushing water into Lake Houston at a rate that could flood residents. Therefore, the SJRA will release at a much more gradual, controlled rate and maintain the lower level until the largest flood threat passes.

Lake Houston, as the lowest lake on the river system, can pre-release more safely. Therefore CWA will pre-release from Lake Houston if the National Weather Service predicts more than 3 inches of rain within the San Jacinto River basin in a 48-hour period. Coastal Water Authority will lower Lake Houston to 41.5 feet from its normal elevation of 42.5 feet.

To track lake levels visit:

  • Lake Conroe – www.sjra.net
  • Lake Houston – www.coastalwaterauthority.org

4 Million People Depend on City for Water

Lake Conroe and Lake Houston comprise two of the largest parts of the City’s drinking water system. More than 4 million Houstonians and residents of the greater Houston region rely on water provided by the City.

Posted by Bob Rehak on July 30, 2018

335 Days since Hurricane Harvey