Full Notification

The rains of the past few days have pushed river levels up.  The Corps has begun reducing releases from Gavin’s Point Dam to help the situation.  Looks like this morning’s NWS update shows the river peaking at 24.9 on Monday morning.  This morning at 11 am I had an elevation shot at hole 8 (I mention hole 8 because it the lowest bank elevation) and the Water Surface Elevation was 1082.8.  At that time, the river stage was 22.8.  So the river should go up another 2.06 feet which would put the water surface elevation at 1084.9 at the peak.  The ground up by the road is 1087 to 1088.  So there is about 2-3 feet of room there.  It should be noted that we did experience similar flood stage earlier this summer and did not have any issues.    The Corps has not yet come out with their update. At these levels and elevations, it will be a manageable situation.  We may stage some preventive measures in case conditions change.  
 
The Big Sioux River is at 29.6 peak on Monday, so based on that we will be closing our valves Sunday night.  I am having pumps placed today in case it would rain while the valves are closed.  The 29.6 is a couple feet lower that what we saw earlier this summer so I don’t anticipate any issues there, but Sioux Falls got a lot of rain last night so that might be a second wave later next week. 

Please open attachment to view the Missouri River at Sioux City & Big Sioux River at Sioux City data.

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