Common Question on Lake Koshkonong Flood Storage

We get this one every time there is high water or a flood stage - if we increase the operating orders for the summer by 7 inches, would the flood of 2013 be that much worse - 7 inches higher than what is was at crest?

Hydrology simplified; 

7 inches = 6,000
Flooding = 1,000,000

Flooding brings 167x more water than what our modest request for 7 inches would bring.

This is taken from the FAQ page.

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...The reason for this is the contrast between the volume of water occupied by the proposed water level increase and the very much larger volume of water contained in a large flood on the Rock River, combined with the hydraulic characteristics of Indianford dam. 

Specifically, if the Lake water elevation was at the proposed target -- 7" higher than the current operating order target, the increased volume of water of water in the lake would be approximately 6,000 acre-feet -- 7 inches over approximately 10,000 acres. 

In comparison, the 2008 flood volume that flowed through the Rock River was over 1,000,000 acre feet. Because the flood volume is so much larger than the storage "lost" in the lake due to the proposed operating order change, the water level in the lake at the beginning of a flood has little effect on the peak discharge that moves out of the Lake. 

In summary, the proposed summer target water level increase is an infinitesimal fraction of the typical flood flow, meaning that peak discharge in the Rock River would be unaffected, and the Lake levels at flood time would be controlled by the inoperable crest of the Indianford dam and the Rock River downstream, and not the gate settings associated with the revised operating order.