FEMA Mitigation Best Practices: Mitigation Programs and Bioengineering Help Communities in Southern Utah Achieve Vision for Flood Control [open pdf - 784KB]
Alternate Title: FEMA Mitigation Best Practices: Mitigation Programs and Bioengineering Help Communities in Souther Utah Achieve Vision for Flood Control
"A major flood in 2005 ravaged the communities, resulting in the loss of 27 homes and triggering a federally declared disaster. Rock riprap, the layering of rocks along the riverbank to counteract erosion, was the primary mitigation technique used following the 2005 flood to rapidly stabilize river banks and protect vital infrastructure and homes from additional damage. Although effective in preventing erosion, the City of St. George recognized the drawbacks to riprap such as increasing the speed of water flow along a length of river causing potential downstream impacts; impeding the natural functions of a riverbank that interface between land and rivers or streams; and, the effect on wildlife, specifically fish. Riprap reduces areas for vegetation or riverbank diversity in which fish seek refuge during high water events and often results in their being washed out of the area during flooding. Riprap also can leave riverbanks with an unappealing man‐made look."
Federal Emergency Management Agency (FEMA): http://www.fema.gov/