<P> The causeway running across the lake was built in the 1950s by the Morrison - Knudsen construction company for the Southern Pacific Railroad as a replacement to a previously built wooden trestle known as the Lucin Cutoff . The route is now owned and operated by Union Pacific . About 15 trains cross the 20 - mile (30 km) causeway each day . Previous to December 2, 2016, the causeway constrained the flow of water between northern and southern parts, which has a significant impact on various industries surrounding the lake . With the construction of a 180 - foot - long (55 m) bridge and the opening of the causeway for water to flow between the arms of the lake, water levels have begun to equalize . The impact of the flow of water from the southern arm of the lake to the northern is yet to be seen . </P> <P> The northern arm of the lake has a much higher salinity, to the point that the native brine shrimp cannot survive in its waters . In the southern portion, where the vast majority of the fresh water inlets are found, the salt level can dip below what is necessary for the brine shrimp to survive, while water in the northern bay is too salty . The salinity of northern arm of the lake will likely drop as lower salinity from the southern arm of the lake flows into the northern arm . The brine shrimp harvesting industry could benefit from the causeway allowing a freer flow of water . There were concerns from the brine shrimp harvesting industry that the lake conditions in the southern arm of the lake were becoming too saline for the brine shrimp due to several years of lower precipitation in the lake's watershed . The precipitation in the watershed has been above normal for the current water year that begins its tracking October 1, 2016 . This additional precipitation has allowed the levels of both arms of the lake to rise, and at least for the near future the conditions for a healthy brine shrimp population seem good . </P> <P> Great Salt Lake Minerals Company (a subsidiary of Compass Minerals) which extracts minerals from the northern bay . The company potentially benefits from the higher salinity of the northwest arm of the lake but has had difficulties accessing water from the lake because of lower water level . Previous to the opening of the causeway they had had to extend their intake channels to reach the water . </P> <P> Morton Salt, Cargill Salt, Broken Arrow Salt and the Renco Group's U.S. Magnesium each extract minerals from the southern bay, and could benefit from a more natural mixture of water between the two sides of the lake . </P>

Dead sea and the great salt lake of utah