HIGH-RESOLUTION SPATIAL SAMPLING FOR TOTAL DISSOLVED SOLIDS AND DISSOLVED OXYGEN IN THE JORDAN RIVER, SALT LAKE CITY, UT: A SNAPSHOT OF WATER QUALITY

Eight segments of the heavily urbanized Jordan River, Salt Lake Co., Utah, are designated as impaired for total dissolved solids (TDS) and dissolved oxygen (DO) by the Utah Division of Water Quality (UDWQ). To identify impairments, 335 water samples were collected from 84 locations in segments 2-6 during each major season - winter, spring, summer and fall. Samples were collected over a 5-7 day period in close proximity to provide a fine resolution data set, a “snapshot” of water quality. Water was analyzed in the field for electrical conductivity, DO, and temperature. Of the 335 water samples, 133 are above the 1200 ppm TDS standard set by UDWQ. Trends decrease downstream through all seasons, however fall and winter increase in the more urban city environment. 5 of the 58 samples collected during the summer 2018 are below the 5.5 ppm DO standard set by UDWQ. Downstream of a major confluence, runoff from a wastewater treatment plant is introduced causing an average of 800 ppm. Major observable changes in TDS and DO occur at confluences in all seasons. At major mountain stream confluences TDS and DO improve with annual spring runoff. Summer variations in DO and TDS occur upstream in the suburban and agricultural areas of the river valley, with surface water runoff as the likely contributor. TDS trends high during winter months downstream in the urbanized segments, likely due to road salts and snow melt in the area. Current data has provided overall seasonal trends in the Jordan River. However, long term and more frequent observations are required for detailed mitigation of impairments. A broad data set allows for a detailed understanding of impairments in the river. With more data to interpret, the UDWQ is better equipped for mitigation efforts towards a clean and healthy river environment.