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VOLUME 3 ISSUE 3 FALL 1993
SWITCHGRASS HOLDS ITS OWN
Summer flooding throughout the Midwest proved one thing - switchgrass is the vegetation for levees. In numerous examples levees which had switchgrass growing on them survived the flooding. Not only did the switchgrass itself survive when the flood waters receded but the levees it was planted on had survived. In one of the most striking examples, a levee which had both fescue and switchgrass growing on it, the fescue portion was gone, not just eroded but completely gone. The adjacent switchgrass area was still intact. The washed away levee exposed the extensive root
system of the switchgrass which made it obvious why it had held. Other levees had fescue planted across their tops but switchgrass near the base of their slopes. The tops eroded severely but erosion stopped when it reached the switchgrass. There was a distinct line, bare soil then switchgrass plants. There were numerous other levees saved by switchgrass by yet another method. As the water topped the levees the tall grass was laid over, forming a protective matte of vegetation stopping all erosion.
The whole situation has many rethinking levee vegetation and management. Fescue or smooth brome and regular mowing to keep the vegetation short previously has been required as levee vegetation and maintenance on federal levees. The St. Louis District of the Corps of Engineers has adopted a switchgrass seeding rate and is promoting it for the revegetation of the levees under their jurisdiction. However, the Kansas City District, despite the overwhelming evidence, refuses to accept switchgrass as an approved vegetation. I asked one official with the Kansas City District why switchgrass wasn't approved. He said, "it doesn't survive flooding, is a clump grass, therefore encourages erosion and attracts burrowing wildlife." I asked what the preferred vegetation was, he said, "brome." This is despite the fact that all grass except switchgrass was killed by the summer's flood.
In addition, switchgrass levees were still in place while many brome and fescue levees are now in the Gulf of Mexico. That tunnel must be a narrow one!
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