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Show 2 - NEW TIMES - JANUARY 1993 — fortunate to have up-to—date informa- flows can have the consistency of tion on the hazards related to topography, geology, and soils. The Utah Geological Survey in 1992 released a cement and are not confined to existing channels. They threaten life as well as property. When this material dries it is not compacted. In Castle Valley some of the debris-flow material has not been completely saturated since it was areas of the Colorado Plateau are in a low earthquake hazard zone. Although there is a fault about 1-1/2 miles long in Castle Valley, the Utah Geological Survey study concluded that the fault and related W are the result of collapse due to dissolving of underlying salt by ground water. Although movement of this fault or the development of sink holes would cause local damage, the study concluded that movement of the fault would not cause a large earthquake. deposited, and is classified as 29112115; M. When this material is saturated by irrigation, roof runoff, or identify some geologic hazards and apply simple rules to make their home septic tank absorption fields, the soil sites, and perhaps those of neighbors, material compacts, causing the surface safer. To minimize the danger of floods and debris flows, determine what nature is trying to do and then work with nature, not against it. Don’t block or try to divert natural drainage channels. Disturb the natural Surface as little as possible, and think about the consequence of adding water to the surface or subsurface. If rocks are on the surface or in the soil, think about how they got there. Large boulders scattered on the surface near steep slopes are probably part of a rock fall. Rocks with well-rounded edges were likely deposited by flood waters. Rocks that are not rounded were likely part of debris flows. The events that deposited these rocks will likely occur again. Think about what a recurrence might quite destructive as the water seeks new channels. Areas below the alluvial fans are also exposed to these floods. More dangerous are the minus that develop when large volumes of soil and rock are carried by the water. These Geologic Hazards in Castle Valley Every area is exposed to natural hazards, and the town of Castle Valley is no exception. In Castle Valley we are report on the geologic hazards in the valley, and the Soil Conservation Service in 1991 published a report that defines 12 soil types in the town and the properties of these soils that should be considered in the development of home sites. Rggk falls are a hazard along much of the margin of Castle Valley. The Utah Geological Survey has to subside, which can damage structures built on this collapsible soil. Much of the soil in the central part of the valley is susceptible to m documented five significant rock falls from Porcupine Rim since 1959. Rocks fall from the rim and roll, bounce, and slide for some distance into the valley. Along the margins of Castle andjjpjng. Piping occurs when water moves rapidly in the shallow subsurface and carries away fine material, leaving “pipes” that then collapse. Erosion and piping can damage structures. Valley, tromielgudburstiraiutoms carry soil and rock into the valley. Some of The larger streams that flow these floods are mostly water, and under natural conditions would be confined to established channels and do through Castle Valley can flood as a result of cloud bursts, rapid snow melt, and extended periods of precipitation. These W can be very large and do considerable damage to lower areas in the valley. Castle Valley and surrounding little damage outside of these channels. Unfortunately, construction in the valley has disrupted the natural drainage, and now these floods can be Anyone can make observations to do to people and structures. ALLUVIAL FAN FLOODING 3: DEBIIS FLOW MAZAID COLLAPSIBLE SOIL ALLUVIAI. FAN FLOODING L DEBRLS FLOW HAZARD COLLAPSIME SOIL A i rocx nu. & /‘ SHALLOW ssnnocx/ A , A I \ ll ‘ SOIL SUIJECT TO EROSION & PWG SOIL SUIJECT TO EROSION A PIPING At /\ STREAM FLOODING \/ \ / 1 / I! ROCK FALL L SMALLOW BEDROCK \ //\ \ l ' \ ‘ \ FAULT RUFTUKE A SINK HOLES The zoning ordinances of the Town of Castle Valley do not regulate development based on geologic hazards. The Castle Valley Planning Commission makes information on the hazards available to all residents and prospective residents, so they can take the actions that will provide the degree of protection they desire. Information on the geologic hazards and actions that can be taken to provide protection from the hazards can be obtained from the Planning Commission. GEOLOGIC HAZARDS ACROSS CASTLE VALLEY FOR SALE: New passive-solar home. SW stucco design. 2 bedrooms and 2 baths. Lots of ceramic tile and custom cabinets. 244 Miller Lane. fimmm 47 E. CENTER STREET MOAB, UT 84532 801-259-2650 JANIE TUFT - SALES AGENT P.O. Box 1121 - Moab, Utah 84532 RES, 801—259-8360 - Leave Message ——Don Mabey |
