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Author Topic: Effect of sea level rise on river heights  (Read 2417 times)

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Effect of sea level rise on river heights
« on: March 27, 2013, 07:14:41 AM »
Possibly silly question coming...

I live near a large, tidally affected and brackish river about 20 km from the coast. The mean height of the river here is about 1.5 m above sea level.
In the ten years I've lived here, sea levels at the coast have risen by 3cm.

Would the mean river height here likely have risen by this much? A little higher? Or a little lower? (assuming the only change is sea level rise, and that flows are constant, etc)

Three cm might seem like two-tenths of sod all, but with 20,000 properties or so affected (not necessarily damaged) in the last major flood, I figure 3cm would add 100-200 to the total.
For an individual property 3cm could be the difference between losing and keeping your carpets, or your ceiling insulation, etc


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Re: Effect of sea level rise on river heights
« Reply #1 on: March 27, 2013, 12:50:48 PM »
The discharge elevation does impact the upstream elevations of a river.  In order to determine the magnitude of the impacts upstream from the discharge (mouth) of the river, the would need to be modeled, (using HEC-RAS or similar software).  The length upstream impacts depend on the river slope and geometry, but in general, the impacts are all contained within the first few hundred feet of the discharge . In your case, the impacts at the mouth would be 3 cm, then further from the discharge point the impact would be reduced to zero.