The effect of irrigation efficiency upon the water demand for agricultural purposes in the Utah Lake drainage area has been evaluated in this study . Irrigation demand is the quantity of water at the supply source necessary to satisfy crop water requirements, taking into account irrigation efficiency. The Utah Lake drainage area was divided into hydrologic subareas and districts to facilitate analysis. The demand, surplus, and deficit quantities for each area was determined. The computations were made using constant mean quantities. Within a given area, the diverted water was assumed to be applied uniformly to satisfy agricultural crop demands, and the contribution of groundwater was neglected. The quantity of major interest is the surplus or deficit, which has been computed for present and potential future irrigation effiencies taking into account historical diversions and precipitation, and estimated root zone storage. The crop demand is not adequately met in the study area. There is a surplus in the Provo district (29,000 acre-feet annually), while deficits occur in the Spanish Fork district (69,000 acre-feet annually) and Northern Juab Valley subarea (38,000 acre-feet annually). The common pattern is excessive diversions in May and insufficient diversions in July through September. The present mean irrigation efficiency of 36 percent in the Utah Lake dra inage area results in an annual deficit of 111,000 acre-feet, of which 69,000 acre-feet occurs in Utah Valley. The maximum monthly deficit is 76,000 acre-feet, which occurs in August. Provided irrigation efficiencies were increased to 68 percent, surplus would exist in every month and the annual surplus would be 159,000 acre-feet. The combination of additional storage facilities to modify the diversion to coincide with crop demand, reallocation of water from water -plenty to water -short areas, and increasing the irrigation efficiency would provide the best economic use of water for the benefit of the area. (169 pages)

Deer flies have been implicated as mechanical veotors of tularemia in Utah. Although infected flies heretofore have not been tound in nature, there is little doubt of their importance in transmitting tularemia to man. Two species present in this area, Chrysops discalis Williston and Chrysops noctifer Osten Sacken, have been shown experimentally to transmit the disease. The presence of deer flies in the environs of Utah Lake where tularemia is endemic oftera a potential health threat to man, and the expanding human population and development ot recreational facilities adjacent to the lake inorease this potential. Despite the taot that deer flies have been implicated with tularemia in Utah, little is known about their distribution or seasonal occurrence in the environs of Utah Lake.

The water quality of Utah Lake is of great importance to agriculture, recreation, and wildlife. The Utah Lake Simulation Model (LKSIM) was created to accurately predict changes in water quality parameters. However, a potential limitation of LKSIM is the age of the underlying data which was gathered from 1930 to 1980. New sample data were collected from March 2009 through May 2011. Samples were taken from 13 tributaries, the Jordan River Outlet, and various wastewater treatment plants (WWTP). Upon dividing the collected data points into seasons and plotting them in Microsoft Excel, trendline equations were produced. These equations correlated TDS and ion concentrations with flow and their respective times of the year. The new equations were compared with the old LKSIM equations by plotting them both against the collected, sample data points. The new trendline equations and mean values proved their worth by generating more accurate predictions of TDS and ion concentrations according to the sample data. However, further studies on the other tributaries of Utah Lake to determine their effect on the water quality may be of value. Also, future sampling from the tributaries of this study may be beneficial in gauging the accuracy of the equations and mean values that were found.

Atmospheric deposition (AD) is a significant source of nutrient loading to waterbodies around the world. However, the sources and loading rates are poorly understood for major waterbodies and even less understood for local waterbodies. Utah Lake is a eutrophic lake located in central Utah, USA, and has high nutrient levels. Recent research has identified AD as significant sources for nutrient loading to the lake to better understand the dust AD sources, we sampled suspected source locations and collected deposition samples around the lake. We analyzed these samples using Inductively Coupled Plasma (ICP) for 25 metals to characterize their elemental fingerprints. We then compared the lake samples to the source samples to determine likely source locations. We computed spectral angle, coefficient of determination, multi-dimensional scaling, and radar-plots to characterize the similarity of the samples. We found that lake deposition samples were more similar to local sources than to distant sources. This suggests that the major source of atmospheric deposition onto Utah Lake is the local empty fields south and west of the lake and not the farther playa sources as previously suggested. Preliminary data suggest that dust AD is associated with dry, windy conditions and is episodic in nature. We show that AD from dust deposition is likely a small portion of the overall AD nutrient loading on Utah Lake, with the dry and precipitation source contributing the majority of the load.

Utah Lake is a shallow eutrophic lake located in central Utah. It is characterized by high nutrient and silt loads and by large algal blooms in late summer and early fall. Phytoplankton samples and environmental data were taken from June through August 1974. Phytoplankton species were identified and then quantified in a Palmer counting cell. Environmental continuum theory was employed to describe algal succession and regression analysis was used to discover interactions between algal communities and the environment. Phytoplankton communities in June were characterized by high species diversity. As the lake environment became stressed in late summer due to higher turbidity, nutrient levels, and pH and decreases in available inorganic carbon,species diversity decreased. By August, the phytoplankton flora was composed essentially of only two species, Ceratium hirundinella and Aphanizomenon flos-aquae.

Spatial and temporal variations of Utah Lake’s flow field were modeled using the Estuary Lake and Computer Model from the Centre for Water Research (CWR-ELCOM) at the University of Western Australia as part of an effort to increase understanding of the lake’s natural processes in order to restore the lake to its pristine, clear-water state and preserve the habitat of the June sucker, an endangered species. The model was validated using temperature measurements taken by sensors in 2007. The water temperature was a strong function of air temperature and incident short wave radiation, and was influenced to a lesser degree by wind speed, wind direction, relative humidity, and cloud cover. The water currents were affected most strongly by wind speed and wind direction. The model also predicted the free drifting paths of June sucker larvae entering Utah Lake through the Provo and Spanish Fork Rivers between mid-April and July.

The channel catfish, Ictalurus punctatus (Rafinesque), was first introduced into Utah Lake in the summer of 1911, and has since been stocked in the lake on numerous occasions. It has only been in the last few years that the channel catfish has become an important game fish in Utah. As the value of the channel catfish, as a game fish, increased, it has become increasingly important to the state to maintain this species for present and future generations. This study was initiated in 1958 and completed in 19 60, and was financed by the Utah State Department of Fish and Game. Data on certain phases of the channel catfish life history were investigated to provide information to aid in management of this species. The following phases were studied: age and rate of growth; age composition of the population; reproduction success; food habits; movements; and extent of the fishing pressure.

Due to the inconveniences associated with under ice population studies, most aquatic population studies are made during the spring, summer, and fall seasons. Like most lakes little is known about the fall and winter popu-lations of the Utah Lake invertebrates. The purpose of this study is to classify, determine quantitative fall and winter population fluctuations, and obtain life history and ecological information of the macro-invertebrates at . Lincoln Beach, Utah Lake. This lake is the largest, natural occurring body of fresh water in the state and has a high potential for the production of gamefish and water-fowl. As Smart (1960) points out, an estimate of the amount of bottom fauna is the most important single stand-ard for evaluating the potential of a lake to produce fish. It is also an important consideration in the evaluation of waterfowl habitats (Barnett, 1964).

The spatial scales at which ecological phenomena are viewed constrain the results of interactions between species and their environments. In lake ecosystems, important dynamics have been identified at the landscape scale and the macrohabitat scale. To determine if landscape-scale effects and macrohabitat-scale effects are important in survival and growth of young June suckers, we compared variation among sites in Utah Lake. Large semi-permeable cages were used to house June suckers in situ at five sites representing landscape-scale variation and two sites representing macrohabitat-scale variation in Utah Lake. We compared survival and growth among sites and related it to resource availability (zooplankton abundances), temperature, and disturbance regime to determine if these were possible drivers of variation. Provo Bay had the highest mean survival and high survival in all four cages. Growth differed among sites: Provo Bay and the northwest site had the highest and lowest mean growth rates, respectively. Survival was higher in vegetated water than open water, whereas growth was significantly higher in open water. Zooplankton densities were highest in Provo Bay and the open water habitat, suggesting a positive relationship between food abundance and growth. Temperature patterns were not consistent with differences in growth among sites. Disturbance was greater in the open lake, which may partly explain the higher survival rates in Provo Bay.

Recent urbanization of Utah Valley, Utah, has highlighted the impacts of anthropogenically-driven eutrophication of Utah Lake, which may lead to more frequent harmful algal blooms. To examine changes in trophic state, three freeze cores were taken from Utah Lake (Goshen Bay, Provo Bay, and near the Provo Boat Harbor) to examine the extent of eutrophication since European settlement. 210Pb and 137Cs chronologies were constructed for all three cores, although due to low supported 210Pb in the Provo Boat Harbor core, an additional pollen analysis was performed. Lower juniper pollen counts in addition to higher POACEAE (grasses and cereals) counts above 27 cm suggests that land clearance was taking place and horizons above this depth are post-1850s, when Utah Valley was settled. Chronologies in Goshen Bay and Provo Bay show that horizons above 40 cm are post-1950s. Hydrogen index (HI) values derived from RockEval pyrolysis were used to characterize the organic matter in the cores. Material from all three cores show an up-section increase in HI, consistent with the increasing deposition of algal matter. δ15NATM and δ13CVPDB isotope ratios were also measured for organic matter in the cores. 15N shows enrichments upward in the cores, combined with a depletion in 13C across all three. δ15NATM values suggest increasing anthropogenic influence with time that may contribute to algal blooms and eutrophication. δ13CVPDB ratios become depleted towards the top of the core showing a change in the lake’s ecology which may be due to the introduction of invasive Phragmites. X-Ray diffraction (XRD) analysis was used to analyze mineralogical differences. Eastern Utah Lake and Goshen Bay cores contain 70-80 % calcite, 10-15% quartz and 10% dolomite. Provo Bay samples contain 50-60% calcite, 20-30% quartz, and 10% dolomite. The dominance of calcite suggests that the sediment is dominated by endogenic minerals, albeit with a greater contribution of detrital minerals in Provo Bay. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used for elemental analysis. Concentrations of phosphorous and trace metals increase in the younger sediment of all three cores, suggesting greater anthropogenic influence on lake water with time. Overall, the rise in HI, P, trace metals, and 15N since European settlement suggests that the lake has become more eutrophic and anthropogenically-impacted in the last 170 years. This highlights the importance of understanding human impacts on water quality to help mitigate any future damage to Utah Lake’s ecology and waterways.