Author Topic: Harris County poised to receive grant to study flood tunnel idea  (Read 562 times)

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Offline thackney

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Re: Harris County poised to receive grant to study flood tunnel idea
« Reply #25 on: February 21, 2019, 12:46:13 PM »
I think that depth was mid-channel wasn't it?  (for waterway navigation) I am talking about the volume near or prior to industrial development.

During the ECHMA meetings, the word "epic" was often used to describe what "best case" drainage benefits say from dredging the HSC from inside the loop to the inlet of the bay.  OF course a high priced feasibility/ cost effectiveness study shot it down.  And of course this is several years before Allison or Harvey.

So reduce the depth to about 6 feet?  How would that help?

Galveston Bay is only about 6 feet deep except where they dredged for the channel.
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Offline catfish1957

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Re: Harris County poised to receive grant to study flood tunnel idea
« Reply #26 on: February 21, 2019, 12:54:08 PM »
So reduce the depth to about 6 feet?  How would that help?

Galveston Bay is only about 6 feet deep except where they dredged for the channel.

Bay depth is inmaterial when considering silting and sludge in a drainage scenario on the HSC.  Existing silt and sludge is what displaces the water than needs to be removed upstream. 

I display the Confederate Battle Flag in honor of my great great great grandfathers who spilled blood at Wilson's Creek and Shiloh.  5 others served in the WBTS with honor too.

Offline Elderberry

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Re: Harris County poised to receive grant to study flood tunnel idea
« Reply #27 on: February 21, 2019, 12:58:45 PM »
So reduce the depth to about 6 feet?  How would that help?

Galveston Bay is only about 6 feet deep except where they dredged for the channel.

Wagons used to cross Galveston Bay from Smith Point to Eagle Point.
He who makes an attempt to enslave me, thereby puts himself into a state of war with me.

Offline thackney

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Re: Harris County poised to receive grant to study flood tunnel idea
« Reply #28 on: February 21, 2019, 01:29:29 PM »
Bay depth is inmaterial when considering silting and sludge in a drainage scenario on the HSC.  Existing silt and sludge is what displaces the water than needs to be removed upstream.

I think that depth was mid-channel wasn't it?  (for waterway navigation) I am talking about the volume near or prior to industrial development.

The original Houston Ship Channel was dredged to 100 feet wide, 6 feet deep.

https://aoghs.org/transportation/houston-ship-channel/

https://tshaonline.org/handbook/online/articles/rhh11

Now it is dredged 45 feet deep for several hundred feet wide.



https://www.swg.usace.army.mil/Portals/26/docs/Navigation/Channel_Survey_Maps/HS/MLLW/HS_07_BGB_20181006_CS_EX_41_MLLW_68000_83305.pdf

It is not silted up and it is maintained at these depths and widths.

What do you imagine with the information I have shared with you could be done in the channel to significantly  improve?  And keep in mind the tunnel project is to get the water to the Houston Ship Channel, not replace it.

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Offline thackney

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Re: Harris County poised to receive grant to study flood tunnel idea
« Reply #29 on: February 21, 2019, 01:47:53 PM »
Life is fragile, handle with prayer

Offline catfish1957

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Re: Harris County poised to receive grant to study flood tunnel idea
« Reply #30 on: February 21, 2019, 03:55:50 PM »
The original Houston Ship Channel was dredged to 100 feet wide, 6 feet deep.

https://aoghs.org/transportation/houston-ship-channel/

https://tshaonline.org/handbook/online/articles/rhh11

Now it is dredged 45 feet deep for several hundred feet wide.



https://www.swg.usace.army.mil/Portals/26/docs/Navigation/Channel_Survey_Maps/HS/MLLW/HS_07_BGB_20181006_CS_EX_41_MLLW_68000_83305.pdf

It is not silted up and it is maintained at these depths and widths.

What do you imagine with the information I have shared with you could be done in the channel to significantly  improve?  And keep in mind the tunnel project is to get the water to the Houston Ship Channel, not replace it.

Outside the channel to near the banks is highly sedimented.  Removal of those sludges would give additonal upstream storm flush capacity (removal of solids displacing volume, bottlenecking flow) .  Back in '92 ECHMA ran the numbers, and thought though not cost effective, would be a way to eleviate some areas of Houston flooding.
I display the Confederate Battle Flag in honor of my great great great grandfathers who spilled blood at Wilson's Creek and Shiloh.  5 others served in the WBTS with honor too.

Offline Elderberry

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Re: Harris County poised to receive grant to study flood tunnel idea
« Reply #31 on: February 21, 2019, 10:13:48 PM »
   
Save Buffalo Bayou

A Ribbon of Life Through the Concrete of Houston

Flood Control’s Destructive Bayou Maintenance Will Lead to More Erosion, More Maintenance

Practices Fall Behind Standards Elsewhere

June 3, 2018

http://www.savebuffalobayou.org/?page_id=5324

Quote
For months we have been receiving complaints about the damage the Harris County Flood Control District is doing to Buffalo Bayou.

Citizens have been sending us video and photographs of contract workers dredging, banging, mucking, bulldozing, slamming and damming the channel and banks; dragging, cutting, and removing large trees, live trees, trees fallen against the banks, trees fallen in the woods.

And now we have reports that they’ve done the same to Cypress Creek in northern Harris County.

The “maintenance” they have done – virtually clearing out the channel and banks — will lead to greater erosion and instability, more sediment and more flooding. And more costly maintenance.

Harvey and the flooding that followed left a huge amount of woody and other sorts of debris in our bayous, our natural drainage system. Buffalo Bayou, our main river, flows from its source in the Katy Prairie for some 53 miles east through the center of Houston, becoming the Houston Ship Channel and emptying into Galveston Bay. For much of that route, the 18,000-year-old bayou remains one of the few relatively natural streams in the city. It accumulated a lot of debris, logjams and snags during Harvey, as did Cypress Creek.
The Importance of Fallen Trees

There are trees along Buffalo Bayou, great tall trees in places, and they sometimes fall into it. Trees have been doing this on rivers for over a hundred million years. Trees, before and after they fall, are a crucial part of the river’s natural system. Overhanging trees shade the water, regulating the temperature. Their extensive roots, together with the roots of riparian plants, anchor the bank, protecting the bank from washing out. When trees fall into the channel, they continue to provide stability to the stream and its banks, trapping sediment, fortifying against and deflecting heavy flows, helping the channel to maintain a healthy width and depth and to form riffles and pools, helping the stream to restore itself more quickly after a flood, and providing food and habitat for the diversity of creatures large and small that sustain the bayou’s ecosystem.

Without trees on and in the bayou, the bayou would become a barren, shifting, sandy wasteland, much more prone to washouts and collapsing banks, unable to stabilize and restore itself, sending increasing amounts of sediment (and trash) downstream. Alarmingly, some scientists maintain that once the trees are gone, as trees on our urban streams continue to be cut down, they cannot be replaced, and their vital function is lost forever.  (pp. 12-13)

Both Buffalo Bayou and Cypress Creek experienced severe flooding as a result of Harvey, for a variety of reasons, though Cypress Creek floods more regularly. Removal or repositioning of some large woody debris that blocks the flow is necessary for what flood managers call “conveyance” as well as recreational paddling. But there are right ways and wrong ways of doing it.

In the past, the practice of natural resource and flood control managers was to remove all large woody debris to improve stream flow or conveyance. But that began to change in the Seventies with the recognition of the importance of fallen trees.  Now the practice around the country is not just to leave strategically positioned logs in streams but actually to put them there, even saving large logs for that purpose. (p. 7)

More at link above.
He who makes an attempt to enslave me, thereby puts himself into a state of war with me.


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