One dam on the Tittabawassee River failed on Tuesday, May 19 after up to 7 inches of rain fell on saturated ground. The Edenville Dam failed, the Sanford Dam is still there. The volume of water submerged it, but it did not fail. If the Sanford Dam had failed, the flood would have been several feet higher in Midland. Here’s a link to a nice map of Midland County. Wixom Lake, behind the Edenville dam completely drained…the river now runs through what was the middle of the lake The lake typically has a surface area of 1,980 acres (8.0 km2), a shoreline of more than 84 miles (135 km), a maximum capacity of 66,200 acre feet (81,700,000 m3), a normal capacity of 36,000 acre feet (44,000,000 m3), and a maximum depth of 40 feet (12 m)..
Sanford Lake has a surface area of 1,499 acres (6.07 km2) and a shoreline length of 34.5 miles (55.5 km). The main body of the lake stretches for about 6 miles (9.7 km) north of the dam, but the water remains deep enough for small boat navigation up past the town of Edenville, Michigan ten miles (16 km) north of the dam. It has a volume of 13,899 acre feet. By comparison, Reeds Lake in East Grand Rapids covers 265 acres. Sanford Lake is slightly over half a mile wide at its widest point, and averages 9.3 feet deep, with a deepest point of 26 feet. It continues to drain. 6 helicopters responded to the dam failures and flooding. Here’s a wider view:
Here’s air video from Ryan Kaleto. Here’s video of the Edenville Dam collapsing. The raging waters. The Tittawabassee River is 72.4 miles (116.5 km) long and drains an area of 2,471 square miles. It empties into the Saginaw River, which flows into Saginaw Bay. Here’s the graph of the water level of the river at Midland:
As of 915 pm Sat. (5/23), the water level is at 19.25 feet, or nearly 5 feet BELOW flood stage. So, it’s over 15 feet from the crest. The river crested at 35.05 ft., which is 1.15 feet higher than the previous record flood in the fall of 1986. The crest moved downstream into the Saginaw River and out into Saginaw Bay. One projection had water up to 9 feet deep in the city proper. Fortunately, we didn’t get that high, because the Sanford dam held. Driver rescued after pick-up truck swept away by floodwaters. As far as I can tell, there were no fatalities or serious injuries with this event.
At 9:15 pm Sat. (5/23), the flow on the Tittawabassee River at Midland was still at 10,400 cubic feet per second, compared to an average flow of 1,260 cfs. The Saginaw River at Saginaw has a flow of 37,400 cfs, compared to an average flow of 4,550 cfs.
As the river gets back to normal flow, there will have to be an inspection of the Sanford Dam – to see if that can be salvaged and later they will determine whether to rebuild the Edenville Dam.
A final note – I’m a little uncomfortable calling this a “500-year flood”. It was a 500-year flood only because a man-made dam failed. This event was part nature and part man.