Kingwood Diversion Ditch Completely Blocked At River Grove

5/26/24 – Now that the flood has completely receded, aerial photos show that the Kingwood Diversion Ditch at River Grove Park has become completely blocked by sand again … for the third time in six years.

Without serious sand-mine reform (which is an unrealistic dream), dredging will become more frequent and costlier. We’re on an unsustainable path. Let’s look at the problem and a possible solution.

Already Dredged Twice Since Harvey

The mouth of the ditch has already been dredged twice since Harvey: once by the Army Corps and once by the Kingwood Service Association (KSA). But earlier this year, two floods redeposited sand that now blocks the channel mouth again.

Boaters report that river access has become increasingly difficult. Now it’s virtually impossible.

KSA owns the park and the boat launch, but not the Diversion Ditch which cuts through the park. The City and County have responsibility for that.

Regardless, KSA has obtained dredging bids north of $800,000 to keep the boat docks open. To put that in perspective, it’s one third of the organization’s cash reserves. And that will force KSA to decide whether it wants to continue funding a boat launch.

But a bigger, more important question remains. If the sediment continues to accumulate, how many people will flood? Hundreds flooded behind a Diversion-Ditch blockage during Harvey.

As sand builds higher, the problem will become more dangerous. So, where is all the sand coming from?

For this story, I started at River Grove and worked my way upriver toward a hellish, out-of-control sandscape on the West Fork just above Kingwood. It typifies 20 square miles of sand mines in a 20-mile reach of the West Fork between US59 and I-45. But let’s talk about River Grove first.

River Grove Boat Launch Blocked

Today, on a hot Memorial Day Weekend, every boat owner in Kingwood would normally flock to River Grove. But the parking lot was virtually empty this morning. Here’s why.

*An emerging sand bar has totally blocked the boat launch.*

While I took pictures at this location, one man with a small, flat-bottomed johnboat came in. He had to get out of his boat and drag it on foot across the sand bar. The sand bar totally blocks larger boats. To that point, note the virtually empty parking lot in the picture above.

Following the Sand Upstream

So, I took a short drive upstream to see where the sand came from. The next stop: the confluence of Spring Creek and the West Fork, a few hundred yards upstream from the US59 Bridge. The confluence has looked like this for the last month.

*Slightly upstream from the US59 bridge. Spring Creek (left), West Fork San Jacinto (right).* *5/26/24.*

That water on the right looked very dirty. So I followed the sediment trail upstream. It led to the hellish sandscape mentioned above. See below.

Full Scope of Damage Near Hallett Mine Now Apparent

As floods have receded, the damage to mines in the river’s floodway and floodplains has become apparent. So has damage to the river system itself.

During the storms, the river cut through the dike of an abandoned sand pit owned by Hallett until January 2024. That’s when Hallett sold it to a real estate developer, according to the Montgomery County Appraisal District records.

Within days of the sale, the year’s first flood breached the dike at the downstream, southern end of the pit. Later, in May, a second flood breached a dike on the upstream, northern end.

Then the river started flowing through the mile-long, half-mile-wide pit and abandoned its normal channel. It churned up massive amounts of exposed sand and carried it downriver. The river’s velocity was more than sufficient to transport sand.

As more and more stormwater went through the sand pit, less and less went down the normal river channel. Water velocity slowed in the channel and sand dropped out of suspension. That created an enormous blockage that now appears to have cut off the river channel.

No one has yet taken steps to rebuild the broken sand mine dikes. Nor has anyone cleared the river channel. Meanwhile, the West Fork is running through an abandoned sand mine and carrying sediment downstream. See pictures below.

*Looking upstream over West Fork San Jacinto. Channel has filled in with sand and river has rerouted itself through an abandoned pit* *(upper left)*.

In the picture above, it’s hard to tell where the river even was. It formed an S starting at the lower left.

*Where river exits southern end of pit and continues down river.*

Between the entrance and the exit, the river looked like this.

*Former West Fork Channel. The channel is totally cut off by sand. Nearby residents estimate the depth of the sand to be 5-6 feet high near the northern breach.*

This one-minute video shows where the river now enters the sand pit and the blockage in the former river channel.

Video shot on 5/26/24

Rain, River-Depth Impacts on Photographs

Environmental factors often influence photography. So, I recorded the following.

Harris County’s Flood Warning System shows that it hasn’t rained at all in the last week. That has reduced rates of flow in the West Fork.

I took all pictures above on 5/26/24. At the time, Lake Conroe was finally approaching its normal level of 201 feet above mean sea level. But the San Jacinto River Authority (SJRA) was still releasing water at a modest 350 cubic feet per second (CFS).

*Screen capture from SJRA dashboard, 12:07PM, 5/26/24.*

The SJRA release from Lake Conroe increased flow in the river past the sand mines.

Downstream, the Coastal Water Authority was discharging almost 4,000 CFS from Lake Houston at the same time in preparation for some repairs on the dam beginning later this week.

*Screen capture from Coastal Water Authority website at 12:18 PM, 5/26/24.*

The CWA release would lower the water level slightly in Lake Houston and near River Grove Park. But it would not affect areas as far upstream as the sand mines.

The Lake Houston water level was several inches to a foot below normal when I took these pictures. The CWA lists the normal pool at 42.4 feet. However, the Texas Water Development Board says that the spillway on the lake has a crest elevation of 41.73 feet.

So, What’s Next?

Note that the Kingwood Diversion Ditch affects drainage of the entire western half of Kingwood. The Harris County Flood Control District listed it as one of the top two priorities among flood-mitigation projects in the Kingwood Area.

Leaving this ditch silted in is not an option. Take boating out of the discussion. Hundreds of homes flooded during Harvey near this ditch when it previously became silted in and backed up.

KSA, a small, volunteer organization, cannot continue to fund the dredging of City and County property as dredging intervals become more frequent. Especially since no one is attempting to reign in irresponsible mining practices upstream.

Kingwood needs help. As a result of the disaster declaration that came after recent flooding, the Harris County Flood Control District should explore using FEMA debris removal funds to remove this dangerous blockage immediately.

The Diversion Ditch project would be an excellent candidate for those funds. We need to make our elected representatives aware of the issue and a possible funding solution.

This FEMA Fact Sheet outlines eligibility for the funds.

Hurry. We only have 30 days from the disaster declaration.

Posted by Bob Rehak on 5/26/24

2462 Days since Hurricane Harvey

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