Various agencies and organizations have monitored the ecology and water quality of Utah Lake and its tributaries for many years. The 2015 Utah Lake Water Quality Study (ULWQS) Work Plan identified the need for a robust and complete data set that would help scientists:
- Build a predictive water-quality model.
- Determine trends in water-quality conditions over time.
- Identify gaps in data collected in 2016 and allow for an assessment of impairment, delisting, and possible refinement of assessment-unit areas.
- Development of Excel databases with all available water chemistry, flow data, high-frequency data, zooplankton, phytoplankton, fish, and macroinvertebrate studies for Utah Lake and tributaries
- Compilation and summary of all reports, studies, and investigations relevant to Utah Lake and its tributaries
- Data-gap analysis and summary of additional monitoring needs
Thorough data analysis would also help determine whether Utah Lake is experiencing an ecosystem shift from a turbid state dominated by free-floating algae that reduce water clarity and limit rooted aquatic vegetation growth to a clear water state dominated by rooted aquatic plants that reduce the resuspension of bottom sediments and phosphorus uptake by cyanobacteria.
During Phase 1, the Division of Water Quality (DWQ) compiled all available data from partners and other groups into a data management system and conducted a literature review of all available and relevant reports, studies, and investigations completed for Utah Lake, its tributaries, and watershed.
Data Acquisition and Compilation
DWQ has emphasized the importance of compiling all available data and housing it at DWQ. During a November 2015 stakeholder meeting, the Division asked group representatives, research groups, and future investigators if they were planning to conduct studies on Utah Lake between 2016 and 2019.
Utah Lake Monitoring
DWQ developed a Sampling Analysis Plan (SAP) to document the procedural and analytical requirements for the ULWQS. The SAP’s two main objectives:
- Support the goals of the Utah Lake Water Quality Study
- Increased understanding of current water quality (nutrients, algae, and organic matter) in Utah Lake
- Increased understanding of nutrient loading to Utah Lake
- Support for development of a predictive water-quality model
- Support for the goals of the Utah Lake Science Panel
- Collect data to forecast harmful algal blooms (HABs)
- Phytoplankton and cyanotoxin testing for HABs
- Real-time, ambient Utah Lake water-quality data from sondes and satellite imagery to aid in HABs forecasting
The 2018 Utah Lake Sampling and Analysis Plan provides details of field sampling efforts, sites, sampling parameters, and sampling approaches used by DWQ to obtain a complete dataset for the 2018 sampling season.
DWQ collected data between 2016 and 2018 on the conditions of Utah Lake at open-water sites and major tributaries. These data benchmark present conditions and will help scientists identify additional studies needed to meet the objectives of the ULWQS.
DWQ samples 13 open-water sites on the lake on the second Tuesday of each month from May to November. Crews collect water-chemistry samples to understand the temporal and spatial condition of Utah Lake at each site. Field crews also document water depth, light penetration (Secchi depth), the color of the water column (e.g., gray, green, silty, etc.) and the presence of algal mats/scum when collecting samples.
DWQ coordinated long-term (seven-month) buoy deployments at three representative locations on the lake during 2016-2018. The buoys were equipped with multi-parameter data sondes and a telemetry system that provided real-time collection and analysis of data. This allowed DWQ to characterize diurnal variations in temperature, pH, specific conductance, and dissolved oxygen.
These buoys also served as an early-warning system for increases in cyanobacteria. These data guide algal and cyanotoxin sampling efforts and help provide local health departments with the information they need if lake conditions warrant a public-health advisory. These sondes record dissolved oxygen, pH, specific conductivity, water temperature, turbidity, chlorophyll a, and phycocyanin within the photic zone every 15 minutes. Deployments capture these data during the critical harmful algal bloom (HAB) season from July through September.
DWQ also collects samples within the major tributary sites to characterize water-quality conditions of tributaries contributing inflows to Utah Lake. The division samples 17 tributary sites every month and documents the presence of algal mats and phragmites whenever samples are collected. Water-chemistry samples from these major tributaries help DWQ understand the temporal and spatial variability of water-quality conditions around Utah Lake.
In November 2017, DWQ deployed ten pressure transducers (PTs) in tributary streams. These PTs are a low-cost and robust method of determining near-continuous flow in streams that are not gaged by another agency such as the U.S. Geological Survey or a utility. The transducers are programmed to log water depth every 15 minutes. Recorded values are stored in the sensor itself and periodically retrieved by field personnel. By combining these logs of water depths with a number of discharge measurements taken at the site, a rating curve can be developed, correlating the depth of water with the measured discharge. Discharge may be inferred from water depth alone once this correlation is established.
The Division of Water Quality (DWQ) is using a two-pronged approach to developing a database for the ULWQS: historic data collection and an interactive data-visualization tool.
Historic Data Collection
In 2016, DWQ began requesting data from all the monitoring partner entities. DWQ used stakeholder meetings in February 2016, October 2016, and May 2017 to encourage groups to submit Utah Lake-related data to DWQ. Unfortunately, some research groups were concerned about sharing data before submitting manuscripts, so the agency did not receive all the requested data. DWQ was, however, able to compile the following historical data:
- Field data collected from sonde(s)
- Water chemistry
- U.S. Geological Survey (USGS) data
- Utah Lake water elevation
DWQ also compiled pressure transducer, flow, and chlorophyll-a data.
Utah Lake Data Explorer
DWQ developed an interactive data-visualization tool called the Utah Lake Data Explorer (ULDE) to facilitate rapid analysis of a wide range of water-quality characteristics in Utah Lake. The ULDE is built on the R statistical platform (r-project.org) using the R package Shiny. The ULDE product is an interactive web app that allows users to generate a variety of Utah Lake-specific data visualizations as real-time responses to date, parameter, and analysis-type selections. More broadly, the ULDE could serve as a platform for conducting future analyses requested by the Utah Lake Steering Committee or Science Panel. The automated platform also streamlines the process of updating plots and analyses as additional data are generated.
The ULDE enables science panel members, steering committee members, and other stakeholders to:
- Rapidly visualize and understand basic patterns in water-quality conditions in Utah Lake.
- Compare conditions in Utah Lake to those observed in other lakes throughout the nation.
- Generate and evaluate hypotheses about Utah Lake.
The ULDE application can be accessed through a web browser. The application is available without the installation of R and dependent packages. Access through the web link requires internet access. A zip package of the application is also available for download for local installation for those who would like to be able to work offline or access source code. Running the ULDE locally requires the installation of the R statistical package and several R packages. A readme file outlining local installation and operation of the ULDE is provided in the zip file.
A bibliography of Utah Lake literature, studies, and theses was assembled during the development of the Utah Lake Pollutant Load Assessment Report. This bibliography was updated with studies available from local universities, researchers, and other readily available sources. A significant new source of publications is available from the Lake Ecology Laboratory, managed by Dr. Jereme Gaeta at Utah State University. These bibliographies were assembled into a single format and are available in Appendix A – Utah Lake Bibliography.
A literature review of a prioritized subset of relevant Utah Lake scientific studies identified in the Utah Lake Bibliography was completed at the end of Phase 1. The review prioritized 40 publications to help answer the Initial High-Level Charge questions developed by the Steering Committee. The review will be used to inform specific key questions in Phase 2.