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Show runoff in 1983 and 1984 resulted in numerous occurrences of local- flooding, landslides and mud- flow problems throughout the valley and in particular along the Wasatch Front streams on the east side of the valley. Also, the rising level of the Great Salt Lake, caused by record runoff from 1983 to 1986 resulted in many millions of dollars in damages to Salt Lake County residents. No single entity has sole authority for flood control management activities. Cities and counties have the necessary statutory authority to act, but at least six other state and federal agencies also have some degree of authority and responsibility. The state's emergency response and hazard mitigation coordination authority rests with CEM. Hazard mitigation planning is usually provided by the state hazard mitigation team following flood emergencies. Pre- emergency planning is also often conducted. CEM assists the county in maintaining their preparedness plans. Thunderstorms are common during the summer and fall months. These produce localized cloudburst flooding. Although the total volume of water produced by these storms is comparatively small, the instantaneous and localized runoff rate can be high. Damage from thunderstorms most often takes the form of erosion and sediment transport and deposition. Significant landslides and mud- flows can also result from these storms. Typically, these events occur along the hillsides or at the canyon mouths and adjacent residential developments. 13.5 Drought Problems Droughts do not pose as great a threat to life and property as floods. Droughts generally are more of a nuisance than a natural disaster. This is primarily because existing reservoirs make it possible to provide water for essential life functions throughout the period of drought. The industry most impacted by drought is the agricultural community. Ironically, the agricultural community usually has the senior water rights. In periods of extreme drought, when all users are required to cut back on water consumption, the farmer can suffer significant financial losses if not total crop failure. Another water use significantly impacted by drought is the wildlife and waterfowl management areas adjacent the Great Salt Lake. These water users are located at river's end and have come to rely heavily upon return flows as well as the natural flow of the river. Water shortages can result in disease and death for significant numbers of waterfowl and wildlife. The municipal area's have weathered the recent periods of drought fairly well. This has been primarily because existing culinary supplies exceed the current demand and water purveyors have been willing to share surpluses. However, in 10 to 15 years, as the demand approaches the available supply, droughts will pose a much greater threat to the municipal community. 13.6 Other Water- Related Emergency Problems Other disasters can impact water supplies. These generally are more localized in nature than flooding and drought. Included are such things as structural failure of water supply facilities ( i. e. dams and aqueducts), toxic spills, landslides and earthquakes. 13.6.1 Toxic Spills Toxic spills are most likely to occur along major highways such as 1- 15 and 1- 80, or along one of several railroad lines. This somewhat limits the potential for a toxic spill to threaten existing water supplies. Probably the greatest threat imposed by a toxic spill is the possibility of localized groundwater contamination. Groundwater contamination can be hard to detect, hard to quantify and difficult to clean up. For more on this subject, see Groundwater, Section 19. Any type of toxic spill into a river system can have a significant impact upon the waterfowl management areas along the shores of the Great Salt Lake. 13.6.2 Earthquakes The Jordan River Basin, along with the entire Wasatch Front, is especially vulnerable to the effects of earthquakes. This is not only because of the high earthquake potential associated with the Wasatch Fault, but also because state and local building codes and construction methods do not reflect the high earthquake potential of the area. The Dam Safety Section of the State Engineer's Office ( See Section 7 for more details) has been and still is monitoring and inspecting all of the states high hazard dams. High hazard dams are those whose failure would threaten loss of life and/ or significant property damage. Another threat imposed by earthquake is the potential rupture of the Jordan Aqueduct, the Salt Lake Aqueduct, or both. Such a failure would cause 13- 3 |