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Federal Register / Vol. 86, No. 1 / Monday, January 4, 2021 / Rules and Regulations
Located south of Provo Bay, the Spanish Fork River is the second largest stream inflow to Utah Lake, but the majority of the discharge is diverted during the irrigation season June through September; Psomas 2007, p.
12. Adult and larval June suckers occur in the Spanish Fork River UDWR 2006, p. 2; 2007, p. 2; 2008a, p. 3; 2009a, p.
4; 2010b, p. 2; however, the seasonally inadequate flows, poor June sucker rearing habitat at the Utah Lake interface, low water clarity, diversion structures, and miles of levees along the channel are obstacles to successful recruitment Stamp et al. 2002, p. 5.
Adult spawning habitat is limited to the lower 2.7 mi 4.3 km of the Spanish Fork River, where it is of poor quality.
Other tributaries where spawning may occur under favorable conditions include the American Fork River and Battle Creek, but streamflow to Utah Lake in these tributaries is not available most years; therefore, they are not found to comprise a significant portion of June sucker spawning habitat.
Recovery actions for the June sucker to address impacts from water development and habitat modification have included water acquisition, water flow management, and habitat restoration see Recovery, above. The availability of quality spawning habitat will improve species resiliency, and multiple spawning tributaries will improve species redundancy. The positive trend in spawning population numbers, increased number of June suckers, and observations of young-ofyear and age-1 June suckers in the wild indicate that water acquisition, water flow management, and habitat restoration have had a positive impact on June sucker reproduction JSRIP
2018, p. 1; see Species Abundance and Trends, above.
Introduction of Common Carp Historically, Utah Lake had a rich array of rooted aquatic vegetation, which provided nursery and rearing habitat for young June suckers Heckmann et al. 1981, p. 2; Ellsworth et al. 2010, p. 9. However, with the introduction of common carp around the 1880s Sigler and Sigler 1996, pp. 5
6, this refugial habitat largely disappeared. Common carp physically uproot and consume macrophytes and disturb sediments, increasing turbidity and decreasing light penetration, which inhibits macrophyte establishment Crowl and Miller 2004, pp. 1112.
Although not specifically identified at the time of listing in 1986, the successful establishment of common carp and their effects on the Utah Lake ecosystem are a threat to the June sucker
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SWCA 2002, p. 19. However, the previously described carp removal program reduced carp populations and increased macrophytic vegetation in the lake, improving resiliency of the June sucker see Recovery, above.
Urbanization Rapid urbanization on the floodplains of Utah Lake tributaries stimulated extensive flood and erosion control activities in lake tributaries and reduced available land for the natural meandering of the historical river channels Stamp et al. 2008, p. 4.
Channelization for flood control and additional channel manipulation for erosion control further reduced riverine habitat complexity and reduced the total length of tributary rivers for spawning and early-life-stage use Stamp et al.
2008, pp. 1213. It is anticipated that further urban infrastructure development is likely, as the populations of cities bordering Utah Lake and its tributaries continue to increase.
Among the potential impacts from continued urbanization near Utah Lake is the potential for the construction of bridges or other transportation crossings. One example is the Utah Crossing project, a causeway across Utah Lake proposed in 2009 Service 2009, entire. An updated application for the project to proceed has not been filed with Utahs Department of Transportation; however, as development continues on the western side of Utah Lake, the potential need for some type of crossing may increase.
A large-scale project to dredge Utah Lake, remove invasive species, and build habitable islands for private development was proposed in 2017, and is under early stages of planning and review at the State level ULRP 2018, entire. This project has not received any approval or necessary permits at the State or Federal level. We do not expect this Utah Lake Restoration Project or the Utah Crossing project to move forward or impact the June sucker in the next 5
10 years. All development projects on Utah Lake are subject to Federal and State laws, and require consultation with the Service prior to beginning work. However, such projects could potentially impact the June sucker by increasing habitat for predatory fish and restricting June sucker movement in Utah Lake Service 2009, entire.
Additional impacts to water quality due to the runoff from new structures could also pose a threat to the June sucker Service 2009, entire. The UDWQ is partnering with the Utah Lake Commission and other stakeholders to research and provide recommendations
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to improve water quality and address impacts of urbanization and other factors that may negatively impact future water quality UDWQ 2017, entire.
Lake Water Quality Utah Lake is hypereutrophic, characterized by frequent algal blooms and high turbidity Merritt 2004, p. 14;
Psomas 2007, p. 12. The increased turbidity, decreased water quality, and historical change in the plant community from macrophytedominated to algae-dominated see Habitat Restoration, above affect the fishes of Utah Lake, including the June sucker.
High turbidity decreases the feeding ability of many species of planktivorous fish Brett and Groot 1963, pp. 56;
Vinyard and OBrien 1976, p. 3, and can result in a lack of access to sufficient food for rearing juveniles.
Thus, elevated turbidity levels may decrease feeding efficiency of June suckers by limiting their ability to visually prey on preferred plankton food types.
Utah Lake is listed on Utahs 2016
section 303d list for exceedance of State criteria for total phosphorus and TDS concentrations UDWQ 2018, p. 3
7. The majority of the total phosphorus load to Utah Lake is from point sources.
Although Utah Lake has naturally elevated salinity levels compared to other intermountain freshwater lakes, the concentrations are substantially higher today than they were before human development Psomas 2007, p.
8. Within Utah Lake, natural salinity levels are due in part to high evaporation rates, which are a function of the lakes large surface-area-to-depth ratio and drainage basin characteristics.
Evaporation naturally removes about 50
percent of the total volume of water that flows into the lake, resulting in a doubling of the mean salt concentration in water passing through the lake Fuhriman et al. 1981, p. 7.
In addition, several natural mineral springs near the shores of Utah Lake contribute dissolved salts, although the magnitude and effect of these sources has not been quantitatively evaluated Hatton 1932, p. 2. Evaporative losses continue to be the main driver of salinity concentrations in Utah Lake.
However, settlement and development of the Utah Lake basin since the 1800s led to increases in irrigation return flows containing dissolved salts, which likely exacerbated natural salinity concentrations within Utah Lake Sanchez 1904, p. 1. Despite the human influences on inflows, in recent years, salinity levels in Utah Lake have not
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