First Dredge Moves Down River

Ever since Hurricane Harvey departed the Houston region more than a year ago, anxious residents have waited for this day. Today dredges begin removing massive amounts of sediment blocking the West Fork of the San Jacinto River. The Army Corps conducted a survey that confirmed the sediment contributed to flooding. But it has taken virtually six months to bid the project, award the job, and mobilize.

The first dredge has left it’s dock at the command site for the Emergency West Fork Dredging Project. Photo courtesy of Lake Houston Area Chamber of Commerce.

This morning, the first dredge left its dock.

As late as yesterday afternoon, workers were busy preparing it.

Final prep on first dredge happened on Tuesday, September 18.

Cranes loaded final supplies onto dredges at the US Army Corps of Engineers Command Site on September 18, 2018 for the Emergency West Fork Dredging Project.

Overcoming Delays

In the last few weeks, the Corps experienced several delays. First a key part for the first dredge had to be remanufactured and shipped to the job site. Then heavy storms swarmed the Houston area last week. Because the cranes above act like lightening rods, every time thunder was heard, work had to stop until the threat passed.

Finally, as other equipment such as dredge pipe and booster pumps were moved down the river into position, it became apparent that additional sedimentation had clogged the river since the Corps did its initial survey. That meant that sediment had to be removed before the dredges could get into position to start dredging.

Here are two pictures that show the depth of the pontoons on the barge and one of the areas it must move through.

Note the depth of the pontoons on the barge; image taken several weeks ago when dredge was being assembled..

It must move through water as little as 18 inches deep to get to its starting position.

A giant sandbar almost completely blocks the west fork of the San Jacinto River just downstream from River Grove Park.

Clearing the Way

The Corps stated Monday that mechanical dredges were scooping out a channel for the hydraulic dredges and on Tuesday, this scoop was seen between River Grove and the blockage above.

Clearing the way for the hydraulic dredges

Starting at West Lake Houston Parkway and Moving Back Upstream to River Grove

According to the Corps, dredging will start in the Kings Harbor area, slightly east of the West Lake Houston Parkway Bridge. Work will then progress upriver toward River Grove Park in Kingwood, the end of this particular project.

Plans for Subsequent Phases Still Uncertain

No one has yet announced plans to dredge the mouth bar, the East Fork or to perform maintenance dredging after all of the major blockages have been removed.

For those who wonder how this dredging will work, the dredges stir up sediment then suction it into pipelines that are miles long. Booster pumps stationed at regular intervals keep the slurry moving through the pipes back upstream to old sand pits where it will be stored.

How Dredging Works

This picture shows the business end of the second dredge.

This object will be lowered into the water and rotate to stir up sediment which will then be suctioned into pipelines that carry the slurry back to placement areas.

Dredge pipeline is already in place.

Periodic booster pumps will keep slurry moving upriver to disposal areas.

Safety Warning

The U.S. Army Corps of Engineers requests recreational boaters to stay a safe distance from dredging operations. This equipment weighs hundreds of tons and cannot maneuver as quickly as recreational boaters. Don’t expect them to get out of your way. The safest thing to do is to stay out of this reach of the river until dredging has completed.

Posted by Bob Rehak on 9/19/18

386 Days since Hurricane Harvey