This study attempts to give a preliminary survey of the marsh habitat in Powell's Slough near Utah Lake. The following aspects are treated: seasonal waterfowl utilization of the slough, productivity of nesting water-fowl, description of the vegetation, invertebrate analysis, and analysis of environmental factors that may influence the habitat.

Early in 1952, walleye fry were stocked for the first time in Utah Lake. Subsequent plants were made in 1954, 1955 and 1956. Altogether, over two million fry have been stocked. By January, 1958, it was felt sufficient time had elapsed for the species to establish patterns of growth, reproduction, food habits and consequent relationships to the new environment . Thus, on January 1, 1958, a Federal Aid to Fisheries project, number DJ F-4-R-5, job T, was initiated. This project was entitled "investigations of Yellow Pikeperch and Channel Catfish of Utah Lake, Utah County." Although the closing date was December 31, 1958, dat a were collected until October, 1959. Funds were allocated by the Utah Fish and Ga.me Department after December 31, 1958, for the continued study. Collection of data on the walleye was taken entirely from March, 19 58, to April, 1960, and all the work included herein is from that period.

Human activities have long had a negative impact on the water quality of freshwater lakes around the world. Utah Lake, located in north-central Utah, has been a subject of such impacts, as the lake experiences recurrent harmful algal blooms during the summer months. Lake warnings and closures have made the public increasingly aware of the ecological and economic impact of these blooms. The objectives of this study were to: 1) compare historical and present-day water quality and ecosystem conditions using environmental data contained in sediment cores, 2) identify whether, and when, Utah Lake transitioned from clearwater to turbid conditions, and 3) incorporate historically-validated lake plant community structure models into establishing forward-thinking lake management targets. The first two objectives will guide lake remediation efforts by providing insight into where lake managers should set our water quality goals and help identify the main driver(s) of eutrophication in Utah Lake. Environmental data from sediment cores indicate a transition in the lake’s recent history, marking a shift to greater phytoplankton dominance, which I attribute to the introduction of invasive common carp around 1881. The third objective provides management and restoration efforts with the water clarity requirements for returning the lake to its historical ecological state.

Utah Lake is a really large but shallow lake located in the arid environment of the Western United States. Due to a variety of factors it is listed by the Environmental Protection Agency as an "impaired water body" and must be closely monitored. Because of its large extent and shallow depth the water quality is heterogeneous and can change rapidly. This means that traditional water quality monitoring methods, which require large investments in field personnel, equipment, and water sample analysis, cannot produce a model that is truly representative of the entire water body. This thesis examines the feasibility of using remotely sensed imagery to develop a water quality monitoring system for Utah Lake that is accurate, repeatable and cost-effective. Due to the paucity of in situ water quality information, this is primarily a pilot study using Landsat satellite imagery collected within a 5-day window of existing in situ water samples measuring chlorophyll a. The brightness values of the imagery were regressed against the water samples to produce a model to accurately predict chlorophyll a concentrations across the entire lake. The results of the pilot study conclude that Landsat imagery could be a very useful monitoring tool if sufficient in situ data for calibration were available.

We analyzed chlorophyll-a (chl-a) concentrations in shallow, turbid Utah Lake using Landsat data from 1984 to 2021. Utah Lake is ~40 km by 21 km, has a surface area of ~390 km2, an average depth of ~3 m, and loses ~50% of inflow to evaporation. This limits spatial mixing, allowing us to evaluate impacts to smaller lake regions. We evaluated long-term trends at the pixel level and for areas related to boundary conditions. We created 17 study areas based on differences in shoreline development and nutrient inflows. We expected impacted areas to exhibit increasing chl-a trends, as population growth and development in the Utah Lake watershed have been significant. We used the non-parametric Mann-Kendall test to evaluate trends. The majority of the lake exhibited decreasing trends, with a few pixels in Provo and Goshen Bays exhibiting slight increasing or no trends. We estimated trend magnitudes using Sen's slope and fitted linear regression models. Trend magnitudes in all pixels (and regions), both decreasing and increasing, were small; with the largest decreasing and increasing trends being about -0.05 and -0.005 µg/L/year, and about 0.1 and 0.005 µg/L/year for the Sen's slope and linear regression slope, respectively. Over the ~40 year-period, this would result in average decreases of 2 to 0.2 µg/L or increases of 4 and 0.2 µg/L. All the areas exhibited decreasing trends, but the monthly trends in some areas exhibited no trends rather than decreasing trends. Monthly trends for some areas showed some indications that algal blooms are occurring earlier, though evidence is inconclusive. We found essentially no change in algal concentrations in Utah Lake at either the pixel level or for the analysis regions since the 1980's, despite significant population expansion, increased nutrient inflows, and land-use changes. This result matches prior research and supports the hypothesis that algal growth in Utah Lake is not limited by direct nutrient inflows but limited by other factors.

Research on the nesting of the Double-crested Cormorant (Phalacrocorax auritus auritus) was undertaken to determine the nesting ecology of the bird on Utah Lake, Utah County, and the possible effects that diking Provo Bay would have on the cormorants breeding there. In 1973, two colonies in Provo Bay were visited weekly to determine laying dates, incubation period, clutch size, and hatching dates. Another colony, located on the dike of the Geneva Steel Reservoir, was visited daily during the spring and summer of 1973. At this colony, egg-laying occurred from 13 April to 17 May. The average clutch size was 3.8, and the egg length and width averaged 60.50 mm x 39.05 mm. An average egg volume of 49.0 cc is first reported for the subspecies. The average period of incubation was 28 days, and 29.5 percent of the eggs hatched, beginning on 20 May and ending 9 June. The young weighed an average of 36 gm at hatching with a beak length of 17 mm and tarsometatarsal length of 11 mm. These increased to 1543 gm, 73 mm, and 58 mm, respectively, in 23 days. The cormorant population on Utah Lake may be severely reduced by the diking of Provo Bay.

From June to November 1967, a study on channel catfish, lctalurus punctatus (Rafinesque), in Mud Lake, Utah Co., Utah was undertaken. The objectives were (I) to estimate if channel catfish are increasing or decreasing in Mud Lake, (2) to estimate the mean size of adult channel catfish in Mud lake, (3) to determine which environmental factors effect the catch of channel catfish, and (4) to determine if the channel catfish in Mud lake are residents year round. A total of 310 mature channel catfish and 920 carp were collected with four hoop nets. Two fingerling were captured by seining. Ratios between carp and channel catfish over a 17 year period had been established which indicated a possible increase in the channel catfish population. With the exception of the fingerIings all channel catfish captured were at least 36.8 cm long with an average of 50.2 cm. A comparison between environmental factors (water temperture, turbidity, water level, and barometric pressure) and the catch showed that only water temperature changes had a statistically significant influence. Large catches during June, July, August, and September were recorded. In later months the numbers of fish captured decreased and no channel catfish could be seen when tho water cleared. It appears that channel catfish utiIize Mud Lake only during the summer.

The reproductive biology of the brooding leech Helobdella stagnalis (Linnaeus) in Utah Lake was studied for an 18 month period from June 1970 to December 1971. In determining the annual reproductive cycle, the number of adult leeches carrying eggs or young were counted at weekly intervals during the reproductive season and monthly during the rest of the year. Gonadal staging data from histological sections were correlated with the field collection data. It was found that two broods of young were produced by the adult animals during the reproductive season. Continuous water temperatures were recorded at the study site throughout the period of this investigation. Temperature was found to have an effect on the rate of gametogenesis, development, and the number of broods produced. The gonads have an off-on type of activity. When the testes are active, the ovaries are dormant and vice-versa.

This study was conducted to augment the limited information available regarding the Snowy Egret in the Utah Lake area of Utah. Field observations included the following: nesting habits; egg and clutch sizes; sexual, defense, and feeding behaviors. Analysis was made of the distinguishing subspecies characteristics (culmen, tarsus, and wing length) of the Snowy Egrets and of the distribution of the birds. Field observations showed that growth measurements of the young varied from 16.75 g at hatching to 260.58 g after 17 days. Culmen and tarsus measurements were 15.41 mm and 14.12 mm to 53.18 mm and 62.18 mm, respectively, after 17 days. The average clutch size was 2.93 eggs per clutch. The average egg measured 43.85 mm by 32.44 mm. Hatching success was 50.85% in the two major periods of hatching noted. The lack of distinct lines of differentiation between existing subspecies leads the author to question the validity of the current subspecies designations.

Atmospheric deposition is a marginally understood source of nutrient loadings to waterbodies. Atmospheric deposition occurs via wet (rain, snow) and dry (gaseous and particulate transport) pathways. Bulk atmospheric deposition is defined as the total deposition from both wet and dry pathways. Utah Lake is a shallow eutrophic freshwater lake located in central Utah, USA. Recent studies have shown atmospheric deposition to be a significant contributor to the nutrient budget of Utah Lake. This study presents the analysis using three different methods of six years' worth of wet atmospheric deposition samples from nine locations around the lake, though these samples do include some contribution from dry deposition. We present and compare nutrient loads and nutrient loading rates for total phosphorus, total in-organic nitrogen, and ortho-phosphorus. We conclude that wet atmospheric deposition contributed between 309 to 529 tons of total phosphorus, 1,166 to 2,078 tons of total nitrogen, and 106 to 201 tons of ortho-phosphorus to the lake during the study period. We extracted loading rates for the calendar year (in tons per year) and winter/summer month (in tons per month) from the data from each of the three methods of analysis. We show that wet atmospheric deposition is a significant pathway in which nutrients are transported to Utah Lake.