North Dakota Floods Aggravated By "Global Warming"

Paul R (13:13:48) :
“And for 100 year floods to be happening twice with just over a decade between them, that’s not normal, I don’t care if you “believe” in gloal climate change or not.”

The concept of a 100 year flood is widely misunderstood. It does not mean that the floods will only occur once each 100 years it means that a flood of that severity has a 1/100 chance of occurring in any given year. As mentioned above these are random events and just like tossing double sixes with a pair of dice, you can figure out the odds of throwing double sixes in an infinite series of throws. That said if you throw a double six your odds of throwing another one on the next throw are exactly the same as they were on the first throw. Independent random events do not influence each other so you could easily have more than one 100 year flood in a single season.
The methods of flood mitigation are well known and there are lots of things communities can do to reduce their risk. The big mistake most towns make is building their flood control dikes right along the normal river channel. That gives the river no where to go as it enters flood stage. It is much better to condemn a swath of property a 1/4 mile wide or so on each side of the river and build the flood control structures set back by a 1/4 mile from the channel. You then zone the area inside this flood plain for uses that are little effected by flooding. Things like parks, golf courses, soccer fields, ball fields, City parking lots, elevated river side restaurants etc.
In some cases rather than force relocation, the property owners are offered a choice. If you relocate, we will provide a relocation incentive, but if you get flooded out, you will get no reconstruction benefits (all on your dime) and you will be on your own during the flooding period.
By providing that extra flood impoundment, you greatly slow the flood water flow rates and give it a chance to spread out and it lowers the peak crest at the exchange of a slightly longer period of flooding.
In a town north of Denver, they are built on very flat ground and during heavy thunderstorms they whole area floods. The local community has a simple solution for the problem. Instead of having to put sand bag barriers around the whole town or every structure, all the homes are surrounded by low walls with narrow access areas set up so a simple board could be slid into the gate way, and a couple sandbags is all that is necessary to prevent flooding of the homes yard.
In a known flood area, they could use landscaping to pre-place segments of a flood control structure in critical locations and during flooding their sand bag requirements would be reduced by an order of magnitude.
This has all been done in may communities, it is not rocket science, all you need is the political will and public will to work out a solution that fits the local conditions and minimizes the predictable flood losses every time it floods.
Larry

In my opinion, the flood threat for FARGO in the next several decades continues to be present if AMO and PDO both continue to be negative or cool. Such a pattern existed previously from 1964-1976 and may repeat for the next decade or two if past PDO AND AMO patterns repeat and they last for 20-30 years once they start.[ however, sometime they fluctuate with shorter cycles] The average flow 1965-1976 was 1740m3/sec. , six years had a flow of 1800 m3/sec and four years with 2209-2718 m3/sec. This well above the normal

EM SMITH
The web page you referenced shows maximum flows of 19800 cfm, which translates to about 560m3/s.[1m3/s=35.3146 cf/s ]This is much lower than the 3000-6000m3/s peak flows we talked about earlier at Winnipeg. The difference must be the flow at FARGO and the flow at Winnipeg . The latter receiving the flow from a much larger drain basin? Is this your understanding?

Greg Gladen’s Blog has an interesting, long, post about this at “The Ice Ages Matter (Even Today)”