Document Type

Report

Publication Date

January 1986

Abstract

Introduction: The Great Salt Lake is a terminal lake and as such is one of the major inland bodies of salt water in the world, and the largest lake of brine in the western hemisphere. Its unique features, including its mineral rich waters and interesting shores and islands, make it appealing to both industry and vacationers. Until recently, some of the great waterfowl sanctuaries in the U.S. existed along the easterly and northerly shores of the lake. However, during the past three years record breaking inflow volumes and lower than normal evaporation rates have caused an unprecidented rate of rise in the elevation of the lake surface. The rising water already have caused extensive damages to both public and private properties, including raods, highways, railroads, hunting club facilities, mineral extraction facilities, waterfowl areas, home, water treatment facilities, and agricultural lands. For example, the Southern Pacific Railroad Company has spent many millions of dollars raising the level of the causeway which crosses the lake between Promontory Point and Lakeside on the western shore, and a causeway which was constructed by the State ro provide access to a State park on the northern tip of Antelope Island now stands under approximately three feet of water. Continued increases in the lake level would create further damage to homes, transportation links (including the Salt Lake City International Airport), lakeside industries, and recreation facilities. In order to reduce future damages from the rising waters of the lake, various diking options, among other alternative flood control possibilities, are being considered by the State. Some of the diking options were addressed in a recent feasibility-level engineering study completed by James M. Montgomery, Consulting Engineering, Inc., and a team of sub-consultants (Montgomery 1984). The study evaluates several on-shore (or perimeter) diking altneratives to protect specific facilities, such as waste-water treatment plants. In addition, the study looks at some in-lake diking alternatives which provide certain management options by compartmentalizing the lake. In-lake diking options presented by the Montogmery study included various configurations between points on the wast shore of the lake and the Antelope and Fremont Islands. As might be expected, the Montgomery study shows that the in-lake dikes, although more comprehensive (less selective) in the protection provided, are consideraly more costly both to construct and to maintain than perimeter dikes for the same area. Various possible perimeter dike configurations to protect properties on the east shore are discussed by the Montgomery reoprt. The costs of these structures are compared with the much higher costs for in-like dikes needed to protect the same properties. However, the report, by design, addreses the in-lake dikes purely from a flood protection point of view and does not consider other possible advantages of in-lake diking, including: 1. Possible freshening of the waters in areas enclosed by dikes along the east shoreline to enhance boating and swimming and to enable these waters to be used for irrigation, municipal, and industrial purposes. 2. Capabilities to manage the levels of the water adjacent to the east shoreline in order to optimize conditions for waterfowl santuaries. 3. Providing road access to the Antelope Island State Park, and even the possibilitiy of an additional north-south transportation route by-passing Salt Lake City. East of these three issues needs careful study to evaluate the potential physical and economic impacts. For example, a study of items (1) and (2) should address questions such as: (a) Can water in the impounded areas be freshened sufficiently to permit its use for boating and swimming, irrigation, and/or municipal and industrial purposes? (b) To waht extent will freshening create odors (anaerobic conditions), promote algae growth, and cause other water quality problems within the impounded areas? (c) Will regulation to maintain water and salinity levels suitable for waterfowl habitat preclude other uses such as boating and swimming, irrigation, and/or municipal and industrial?