GEOLOGIC HAZARD AND ADVERSE CONSTRUCTION CONDITION MAPS NOW AVAILABLE FOR THE ST. GEORGE - HURRICANE AREA -- The Utah Geological Survey (UGS) has released a new report that identifies geologic hazards and adverse construction conditions in the rapidly developing St. George - Hurricane area of southwestern Utah.

The report, in DVD format, includes 14 maps showing the location and relative severity of geologic hazards and adverse construction conditions that may impact existing and future development in the 366-square-mile study area. “This new report will allow planners, other city and county officials, geologists, and engineers to determine where geologic issues related to existing or proposed new development exist, and to ensure that geotechnical reports adequately address those issues,” said Bill Lund, UGS Senior Scientist. “The report will also be useful to anyone interested in learning more about hazards and other geologic conditions in the St. George - Hurricane area.”

The most damaging geologic hazard in the area is flooding. The flood of 2005 on the Virgin and Santa Clara Rivers caused damage in excess of $100 million. Other hazards covered by the report include surface faulting, earthquake ground shaking, landslides, liquefaction, and rock fall.

The most troublesome adverse construction condition is expansive soil and rock. Numerous buildings and other structures throughout the area have experienced cracked foundations and walls as well as other kinds of structural, architectural, and landscape damage due to shrink/swell soil and rock. Other adverse construction conditions covered by the report include collapsible soil, gypsiferous soil and rock, caliche, shallow bedrock, shallow ground water, wind-blown sand, piping and erosion-susceptible soils, and breccia pipes and paleokarst.

The report also incorporates a unique GIS search application that permits users to rapidly query specific locations or parcels for geologic hazards or adverse construction conditions present, select the hazards or construction conditions of interest from a dropdown list, and prepare a map and brief report for the area under consideration. A link is provided to a more detailed report for each geologic hazard and adverse construction condition for users requiring in-depth information.

The UGS will train local officials in the use of the search application, and will assist as requested in preparing master plans and ordinances addressing geologic hazards and adverse construction conditions. Contact Bill Lund at (435) 865-9041, billlund@utah.gov

Special Study 127 Geologic Hazards and Adverse Construction Conditions, St. George - Hurricane Metropolitan Area, Washington County, Utah is available for $24.95 at the Natural Resources Map & Bookstore, located at 1594 West North Temple, Salt Lake City (801-537-3320 or 1-888-UTAHMAP; geostore@utah.gov).