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| Scotty’s Trout Dock and Marina floating anchored near Business 65 Bridge after it broke loose from its moorings and slowly drifted down stream pulling its anchors with it. |
Whether from the song by Lenny Kravitz, or a quote from Yogi Berra, the refrain, “It ain’t over till it’s over” applies to the current flooding event that some are experiencing in the Branson area. The current flood event didn’t start with the torrential rains during the night hours of April 9 into the early morning hours of April 10 nor will it end after the spillway gates on Table Rock Lake are closed, as planned early this week. It started in with record rains in March that used up a lot of the storage capacity of the area’s reservoirs and will not end until that capacity is regained.
Prior to the most recent rains, James D. Sandburg, US Army Corps of Engineers (Corps) Operations Manager, Table Rock Lake Project Office, said that the level of Table Rock Lake was 927.2 which was 75 percent of its flood control capacity, Beaver Lake was at 92 percent of its flood control capacity, and that Bull Shoals Lake was at 77 percent of its flood control capacity. The flood control capacity percentage relates to the actual current elevation of the lake as compared to the top elevation of the Flood Pool.
Although lake levels will fluctuate, the top of elevation for a specific lakes Flood Pool will not. The elevation for the top of the Flood Pool is 1130 for Beaver Lake, 931 for Table Rock Lake and 695 for Bull Shoals Lake. According to information received from the Corps at various meetings, these are critical levels in terms of flood control management and play a major part in the decision of when and how much water is released through the spillways of the dams controlling the lakes. After the actual rain itself, it is the releases through the dams that will actually cause the flooding. As a general rule, once a lake’s elevation gets to the top of its Flood Pool any water coming in will be passed through in the form of a release from the dam.
As an example, prior to the most recent rain, the elevation of Table Rock Lake had dropped to the 926.8 range on April 9 with a combined release of about 20,000 cubic feet of water per second (cfs) from its spillway and generators. It was lowering its levels by passing its water into the 25 percent of Bull Shoals storage capacity that was left even as it was acting as the storage for the inflow from Beaver Lake. As a result of the most recent rains however, a lot of that flexibility was quickly removed.
The elevation of Beaver quickly rose and exceeded the top of its Flood Pool necessitating releases into Table Rock Lake which, based on projections of exceeding the top of its Flood Pool level had to increase its releases from the 20,000 cfs prior to the rains. The necessary, unprecedented and record breaking release of in excess of 45,000 cfs is the primary cause of the major portion of the flooding problems currently being encountered. That release will continue and be modified as necessary to keep Table Rock as close to the top of its Flood Pool as possible.
Information received from the Corps indicates that as of 6:00 a.m. April 12, Beaver Lake had crested and had dropped back to an elevation of 1129.8 leaving very little storage capacity to handle another rain event. The same information indicates that Table Rock Lake crested at 933.25 at about 4:00 a.m. on April 12, its elevation as of 6:00 a.m. was 933.20, and that has no storage capacity to handle another rain event. As of 5:00 a.m. April 12, Bull Shoals Lake had not crested and its elevation was 693.4 with 1.6 feet left to the top of its Flood Pool. With the inflow from the Table Rock Lake releases to get its level back to the top of its Flood Pool it is expected that there will be very little if any storage capacity left in Bull Shoals to handle any future rain event.
The flooding from the last rain occurred when there was more than 25 percent of the capacity of Table Rock Lake and Bull Shoals Lake available to handle the rain. That cushion is gone until the lake levels can be lowered. Unfortunately, that will be a long slow process because of the limited storage capacity of Bull Shoals which limits the amount that can be released from Table Rock. That is compounded by the limited storage capacity in Table Rock which limits the amount that can be released from Beaver.
Bottom line, even if the spillway at Table Rock Dam is shut down early next week and the current flooding is abated it doesn’t mean that the danger of flooding is over. With the current lake levels, the danger of flooding from a two or three inch rain event similar to the most recent rain will be a danger that the area will be living with until the storage capacities of our areas lakes get to the point where they can handle additional storage.
