Flooding River flowing uphill?

[thackney]

Alright folks, help me understand what has happened.

Brazos River has flooded.  At Richmond, about 4 days ago, it crested and has dropped about 4 feet.

Downstream in Rosharon, we crested 2 days later, about 2 feet lower than Richmond.  Since then we have dropped inches.

http://water.weather.gov/ahps2/river.php?wfo=HGX&wfoid=18770&riverid=203892&pt%5B%5D=141729&pt%5B%5D=141366&allpoints=143254%2C143714%2C143248%2C141760%2C142486%2C143038%2C143320%2C142716%2C141645%2C142218%2C144625%2C141280%2C143222%2C141729%2C141366%2C143122%2C151714&data%5B%5D=hydrograph

The result, downstream in Rosharon, we are nearly 2 foot higher water elevation.  How did upstream drop below us, without our water flowing back?

[Joe Wooten]

The elevation at Rosharon is 49 ft. MSL, Richmond is 92 ft. MSL. If the flood difference is 2 ft now, then that is the driving head of the water upstream, which cannot overcome the 43 foot difference in elevation between the two locations.

[thackney]

The elevation at Rosharon is 49 ft. MSL, Richmond is 92 ft. MSL. If the flood difference is 2 ft now, then that is the driving head of the water upstream, which cannot overcome the 43 foot difference in elevation between the two locations.

Flood elevations are given in feet above sea level, not relative to the local ground.

[Just_Victor]

Perhaps it's the same way that the crest of a wave of water doesn't naturally fill the trough.

[RoosGirl]

Alright folks, help me understand what has happened.

Brazos River has flooded.  At Richmond, about 4 days ago, it crested and has dropped about 4 feet.

Downstream in Rosharon, we crested 2 days later, about 2 feet lower than Richmond.  Since then we have dropped inches.

http://water.weather.gov/ahps2/river.php?wfo=HGX&wfoid=18770&riverid=203892&pt%5B%5D=141729&pt%5B%5D=141366&allpoints=143254%2C143714%2C143248%2C141760%2C142486%2C143038%2C143320%2C142716%2C141645%2C142218%2C144625%2C141280%2C143222%2C141729%2C141366%2C143122%2C151714&data%5B%5D=hydrograph

The result, downstream in Rosharon, we are nearly 2 foot higher water elevation.  How did upstream drop below us, without our water flowing back?

I am thinking that, just like it took Rosharon two days later to crest than Richmond, if the water were to flow back towards Richmond it would also take that time to go "backwards".  However, not knowing the topography of the area and the details of the drainage system, Richmond may just have better drainage routes than Rosharon does to take water away from Richmond, but not necessarily through Rosharon.

[thackney]

I am thinking that, just like it took Rosharon two days later to crest than Richmond, if the water were to flow back towards Richmond it would also take that time to go "backwards".  However, not knowing the topography of the area and the details of the drainage system, Richmond may just have better drainage routes than Rosharon does to take water away from Richmond, but not necessarily through Rosharon.

The Brazos River flows from Richmond to Rosharon. All the other creeks , tributaries, etc that connects to the River brings water to the river, not take it away.

[Joe Wooten]

The Brazos River flows from Richmond to Rosharon. All the other creeks , tributaries, etc that connects to the River brings water to the river, not take it away.

By the rules of hydraulics, water flows downhill, the means Rosharon is at a lower elevation than Richmond, otherwise, the whole area between them would be one big lake.

[RoosGirl]

I'm just not seeing anything weird.  The graphs and charts show Richmond crest at 54.74 on 6/2, Rosharron at 52.56 on 6/4.  The initial water comes into the river upstream of Richmond, takes a while for the peak to get to Richmond, then a couple days later peaks at Rosharron.  As it flows downhill/downstream at some point along the way it starts stacking up and releasing water slower than it has water coming into it.  The water is stacking up downstream at Rosharron and may start stacking up at Richmond if those conditions persist.

[thackney]

By the rules of hydraulics, water flows downhill, the means Rosharon is at a lower elevation than Richmond, otherwise, the whole area between them would be one big lake.

Yep, a giant lake.

[RoosGirl]

Yep, a giant lake.

One girl's "stacking up" is another man's "lake". :)

I would like to know more about your damn dam.

[thackney]

One girl's "stacking up" is another man's "lake". :)

I would like to know more about your damn dam.

http://aquadam.net/

Not normally used for this type of application.

[RoosGirl]

That's a pretty neat product.  Is it your invention?

[thackney]

That's a pretty neat product.  Is it your invention?

Nope, but I am a customer.

[Joe Wooten]

The Ft. Calhoun nuke plant used those to protect it from the Missouri River floods several years ago. They worked very well until a moron ran a forklift into it......