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Ed Yeates ReportingWashington County's widespread flooding where rivers cut their own channels was an eye opener for Salt Lake County. That's because flood control people here have some new technology that's supposed to block the undercutting of homes.
Residents watched helplessly in southern Utah as flooding rivers sliced out their own channels, undercutting homes that in some cases were more than a football field away from the original river bank. That too could happen along Salt Lake's Jordan River. But the flood plain here is much larger.
While the Jordan River itself is down low a much larger area is considered a flood plain. For example, between about 3900 and 4500 south the water can spread up to a half mile in a a projected 500 year flood.
But new subdivisions within that corridor have a new defense, one mandatory in Salt Lake County. The ground here is ready for some new houses, but something you can't see is buried underneath. Layers of carefully laid rock are waiting and ready in what is called a "launch trench."
Chris Springer, Salt Lake County Public Works: “The reason it’s called a launch trench is because the rocks will literally launch down the slope and protect the slope from any further erosion.”
In theory, engineers say it should work. But the real test is yet to come. Salt Lake has defined 60 countywide flood plains. It can't stop property owners from building in them, but it can now require they build houses and the ground underneath a certain way.
