Utah Lake is one of the largest natural freshwater lakes in the western United States. Snowpack runoff from the Wasatch Mountains and water from numerous small tributaries are the primary sources for water to the lake. Primary inflows include the American Fork River, the Provo River, Mill Race Creek, Hobble Creek, the Spanish Fork River, and Currant Creek, with the Provo River contributing the greatest flow. The Jordan River drains the lake northwards towards the Great Salt Lake.
The lake is hypereutrophic, or overly rich in nitrogen and phosphorus. Excessive concentrations of nutrients cause large seasonal cyanobacterial blooms, low dissolved oxygen levels, elevated pH, and possible cyanotoxin production during harmful algal blooms. The lake is the receiving body for wastewater treatment plant effluent, industrial discharges, stormwater discharges, and nonpoint source runoff. Rapid growth and urban expansion within the watershed may be exacerbating these hypereutrophic conditions. The goal of the Utah Lake Water Quality Study (ULWQS) is to address these conditions through the development of nitrogen and phosphorus criteria that are protective of the lake’s aquatic life, recreation, and agricultural uses.
The ULWQS employs a three-phased approach to investigate and address the role excess nutrients play in the water quality and ecological conditions in the lake.
- Phase 1: Data gathering and characterization
- Phase 2: Development of in-lake criteria for nitrogen and phosphorus
- Phase 3: Implementation planning for Phase 2 criteria
The study is funded by a $1 million grant (95.8 KB) awarded to DWQ by the Water Quality Board in August 2016, with an additional $500,000 awarded by the legislature in 2018.
Phase 1: Data Gathering and Characterization
In November 2015, DWQ initiated the data gathering and characterization phase (Phase 1) of the ULWQS. This phase included coordination of research efforts, data compilation, an evaluation of in-lake water-quality conditions, an evaluation of nutrient sources entering the lake from the surrounding watershed, and development of water-quality models to inform Phase 2. Important elements of Phase 1 included:
- Stakeholder process development – The Utah Lake Water Quality Study Stakeholder Process (872.82 KB) established a 16-member Steering Committee representing diverse stakeholder interests and an independent Science Panel responsible for developing scientifically defensible water-quality goals for the lake. This process will guide Phase 2 and Phase 3 of the study.
- Data compilation – DWQ created a water-quality database containing data from all known sources.
- Data explorer – DWQ developed the Utah Lake Data Explorer tool to visualize and analyze Utah Lake water-quality data.
- Literature review – A comprehensive Utah Lake bibliography was developed during Phase 1 and includes research literature related to water-quality conditions in the lake. Building on this bibliography, DWQ completed an in-depth literature review to identify the studies included in the bibliography that are highly relevant to the ULWQS.
DWQ also developed and implemented a water-quality monitoring program for the 2018 field season. The data-collection effort was designed to support the Science Panel, supplement existing datasets, and advance scientific understanding of harmful cyanobacteria blooms on the lake. DWQ sampled 11 open-water sites on Utah Lake and 18 inflow sites during the summer of 2018.
The Phase 1 report was completed in 2018 and delivered to the Steering Committee and Science Panel.
Phase 2: Site-Specific Criteria Development
Phase 2 is the core responsibility of the Steering Committee and Science Panel. These two groups will evaluate factors that negatively impact the lake’s designated beneficial uses, guide additional research to address data gaps, and develop site-specific criteria for phosphorus and nitrogen.
The January 2018 Steering Committee kick-off meeting initiated Phase 2. The Steering Committee accomplished several significant tasks during 2018, including nomination and selection of the Science Panel Membership and development of the Science Panel Initial Charge. The Science Panel Initial Charge directs the Science Panel to answer the following questions:
- What was the historical condition of Utah Lake pre-settlement with respect to nutrients and lake ecology? What trophic-state (nutrient) shifts and significant transitions have occurred since settlement?
- What is the current state of the lake with respect to nutrients and ecology?
- What additional information is needed to define nutrient criteria that support existing beneficial uses?
The Steering Committee also developed the ULWQS Public Engagement Plan.
The Science Panel met several times beginning in May 2018 and has focused its work on addressing the Initial Charge questions as well as preliminary identification of data gaps to guide future research activities.
Phase 3: Implementation Planning for Phase 2 Criteria
Phase 3 of the ULWQS, currently planned to begin in 2020, will focus on implementing the criteria developed during Phase 2 and may include the following elements:
- Evaluation of current use designations and the scientific and economic feasibility of achieving recommended criteria.
- Implementation of water-quality and watershed models to help identify sources of phosphorus and nitrogen, identify reductions required to meet criteria, and inform decisions on how to best reduce nutrient loading.
- Evaluation of costs to implement required reductions.
- Evaluation of scenarios for achieving the most cost-effective solutions for reducing excess nutrients.