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Thank you to everyone who attended the 11th Annual Salt Lake County Watershed Symposium! This free two-day conference encourages a comprehensive review of the current state of our watershed while creating learning opportunities for a diverse array of stakeholders. Sessions covered a broad range of topics on water quality and watershed issues with local, regional, and national relevance. Hosted by Salt Lake County Watershed Planning & Restoration.

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"The Symposium is tremendously important to the future of all of Utah. You guys are educating stakeholders across Northern Utah in an objective, user-friendly way about issues, problems and concerns that are not being discussed publicly anywhere else."  -Zach Frankel, Utah Rivers Council


Thursday, November 16 • 3:30pm - 4:00pm
Creating a Balance: Great Salt Lake Causeway Improvements

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Creating a balance: Great Salt Lake Causeway Improvements

Summary:
Infrastructure improvements to the Great Salt Lake railroad causeway provided a new structure with control berms to modify the water and salt transfer to meet regulatory, industry and ecosystem objectives.

Full Abstract:
Getting trains across the Great Salt Lake has posed a challenge since the completion of the Transcontinental Railroad in 1869, almost 150 years ago. Built in 1902 and modified in 1959, the railway corridor consists of a rock causeway which had two concrete culverts allowing water, salt and boats to pass between the arms of the lake. The semi-permeable rock causeway divided the lake in two, creating a unique ecology where bacteria in the salt saturated north arm turns the water pink, while fresh water flowing into the less saline south arm keeps the water blue. Safety concerns led Union Pacific Railroad, current owner of the causeway, and environmental regulatory agencies to develop a phased permitting strategy to start the closure the culverts in 2012 and determine required mitigation to replace the water and salt transfer and navigability provided by the culverts. Union Pacific, regulatory agencies, and HDR’s environmental and engineering team developed an innovative solution: a new 180-foot-long bridge with a 150-foot control berm. Side adjustable earthen control berms, and a 5-foot invert berm on the lakebed, allow control of the salt and water transfer to meet ecological, industry and lake management objectives. To find the optimal causeway opening that would duplicate the culverts functionality, the team developed several water and salt balance model simulations, modifying the USGS’s Water and Salt Balance Model—the first extensive modeling of the lake since 1998. The effort included updating and recalibrating the model with 14 years of actual lake inflows, salinity and evaporation data, as the Great Salt Lake’s size and salinity is tied to water inflows and weather cycle fluctuations. The team ran various 25-year historical scenarios and compared salinity conditions for different causeway opening geometries. This effort, along with federal and state agency peer review, provided regulating agencies and stakeholders with new understanding of the water and salt transfer and make the updated model innovative and irreplaceable. Final permit was issued on September 9, 2015, and construction started on October 1, 2015. Designing and constructing a stable structure amidst difficult geological and chemical (high salinity) conditions was another significant challenge. The center of the causeway spans two tectonic faults, between which fills with soft sediment—the culprit behind the culverts failure. The new bridge was built in more stable geological conditions with 49 piles driven to over 200 feet—unique for a less than 35-foot-deep lake. Temporary access roads and a track shoofly routed maintenance vehicles and trains around the mid-lake site during construction of the bridge structure, berms and excavated channels. Project completion in December 2016, marks a renewed cooperative effort among Union Pacific, regulatory authorities and environmental advocates to protect and preserve the extraordinary assets of the Great Salt Lake. The project is highly valued by Union Pacific, which maintains causeway safety and operation; state officials, who have a long-term, lake management solution; and environmental groups, who see the lake’s ecological resources continuing to thrive.

Speakers
WG

Wally Gwynn

Former Utah State Minerologist, retired
J. Wallace Gwynn worked briefly for Phelps Dodge Corporation, Amax Magnesium, Great Salt Lake Minerals and Chemicals, and then, after 34 years of service. As a saltines geologist, he retired from the Utah Geological Survey. He started his own consulting business, J. Wallace Gwynn... Read More →
avatar for Karen Nichols

Karen Nichols

Water Resource Engineer, HDR
Karen Nichols is a water resource engineer with HDR in Salt Lake City, UT. Ms. Nichols has more than 30 years of experience working with public and private clients providing environmental compliance, permitting, mitigation, and audits. She specializes in Clean Water Act (CWA) compliance... Read More →
KW

Kidd Waddell

Former USGS Hydrologist, retired
Kidd Waddell was raised in the small town of Roby, Texas where drinking water was scarce and had to be delivered by truck from reservoirs 20-50 miles distant. Consequently, after graduating with BS from Texas Western (now UTEP) in 1962, embarked on a 42 year career with the USGS primarily... Read More →




Attendees (22)