Ike raises rivers

Here’s a quick look at the flows in the Neches River (pronounced “NAI-ches“) in East Texas following Ike.

From what I’m seeing, the Neches sort of dodged a bullet.

At it’s midpoint in Big Thicket National Preserve, near Evadale, flow in the Neches River only jumped around 2,000 cubic feet per second — from 3,000 to 5,000 cfs — following Ike’s boomerang across East Texas.

You can see that on the graph below.

The graph displays the current flow rate in the Neches (at Evadale) in comparison to the 25-year record. The “outer” gray band displays 25 years of minimum and maximum flows. The “inner” skyblue band shows the 25th and 75th percentile (50 percent of the past 25 years fall within that band).

The graph also shows the median and average flow year over the past 25 years. But don’t be deceived, the “median” is a much better metric for getting a handle on “typical” river flows. It isn’t distorted by really big flow events as is the “average.”

The take home point for the Neches is that Ike raised it up on the high end of summer spectrum, but it’s not anywhere near the historic highs.
However, this may warrant a second (and closer) look:
There’s a distinct possibility that some of Ike’s peak flows were absorbed by upstream B.A. Steinhagen Reservoir, behind Town Bluff Dam. If I remember correctly, the reservoir was recently lowered (in part to treat exotic vegetation) and, similar to Lake Okeechobee prior to Fay, may have had some extra room to spare.
(Don’t you love a hydrologic mystery?)


And compare the flows in the Neches to what happened just one basin over — in the Trinity River Basin — right next to where Ike made landfall in Galveston Bay.
The Trinity River’s flow rate increased ten-fold, from 1,000 cfs to 10,000 cfs, in the days following Ike. That puts its current flow rate up at the 25-year record for mid-September!

But 10,000 cfs is only high by late summer standards.

The same flow rate in the spring would fall right along the median.

Isn’t the water cycle like that?

Big by “fall” standards may equate to only a median “spring.”

Of course that’s reversed in south Florida: we have “Big Water” falls and “Plummeting Water” springs.

The bigger question in Texas — especially along the Neches — is how high the water rises into the riparian floodplain corridors, and how long it stays there.

More on that later.

Many thanks to the U.S. Geological Survey for making the flow data available.
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