Record Details
page 3-23
Digital Collections at BYU
| Field | Value |
|---|---|
| Title | page 3-23 Diamond Fork System Final Supplement to the Final Environmental Impact Statement, page 3-23 |
| Coverage | Electronic reproduction; |
| Format | 3-23 text/PDF |
| Rights | Brigham Young University; http://lib.byu.edu/about/copyright/generic.php Public Domain Public |
| Language | English; eng; en |
| Relation | Central Utah Project; Western Waters Digital Library; water 335.2 3352 3352 groundwater quality no baseline groundwater quality data are available for the sixth water or diamond fork creek drainages or for the spanish fork river drainage in the immediate vicinity of the river however monitoring of the strawberry tunnel outlet revealed that during times of seepage flow groundwater alone selenium concentrations can exceed chronic aquatic life support standards in this area in southern utah valley through which the spanish fork river flows and in which diverted spanish fork river water is used for irrigation groundwater is typically a bicarbonate type bicarbonate constitutes over 50 percent of the reactive value of the anions dissolved within the groundwater shallow groundwater tends to be higher in salinity than surface water entering the valley but is generally of good quality CUWCD 1998c 33.6 336 336 impact analysis 336.1 3361 3361 methodology impacts were estimated using a quantitative mixing analysis for sixth water creek diamond fork creek and spanish fork river this analysis used weighted average concentrations to determine impacts of strawberry reservoir water additions on river water quality for the parameters shown in table 36 3 6 basic data from the USBR USER from 1988 to 1998 were used for strawberry reservoir and spanish fork river below spanish fork diversion dam to utah lake averages data from 1995 through 1998 were used to assess other portions of the sy system stern where data were insufficient or incomplete historical data 1978 to 1982 CUWCD 1998b were used or combined with new data to complete the analysis data were not available for fifth water creek therefore values for sixth water creek were used the water quality impact analysis is based on flow weighted averages where available an air temperature and climate mixing model analysis see water quality technical memorandum CUWCD 1999f was conducted to determine the potential for freezing conditions that might result in flooding above the spanish fork diversion dam the temperature mixing model is limited in its ability to predict when freezing may occur and does not take into account effect of flow volume on water temperature equilibration with ambient air temperature spanish fork diversion dam was chosen for this analysis due to completeness of available data and because this location provides a boundary condition for assessing potential impacts on downstream dams this analysis used historical minimum monthly average air temperatures and 1997 and 1998 maximum daily wind speed and minimum relative humidity to determine whether river water would cool to below freezing during the winter these data were obtained from the utah climate center water releases occur from below the potential thermocline depth throughout the year because the syar tunnel inlet is positioned at the bottom of Br bryants bryanfs bryanos abryants yants fork bay with a designed full storage capacity depth of approximately 90 feet below the reservoir surface actual depth would vary depending on the water level in strawberry reservoir analysis of historical data shows that the maximum sampled depth of Br bryants bryanfs bryantt yants fork bay was at least 26 feet and averaged at least 44 feet thus it is reasonable to expect that bryants abryants Br yants fork bay releases would be from below 33 feet deep on average thus below the thermocline if stratification occurs A thermocline is likely to form in a water body this deep during the early summer lasting until early fall may to october USBR 1988c in previous studies it was determined that releases would occur from both above and below the strawberry reservoir thermocline because the cofferdam between bryants abryants Br yants fork bay and strawberry reservoir was at a fixed location this cofferdam has been partially removed and now water flow between the two systems is continuous for the upper 90 feet consequently water releases would be from below the thermocline when strawberry reservoir is stratified or from mixed conditions when the reservoir is not stratified the impact analysis also examines phosphorus concentrations and temperature variations depending on whether releases only would be made from deep water that may be below the thermocline or from n mixed axed waters within 323 3 23 diamond fork system FSFEIS FS FEIS |
| Identifier | http://cdm15999.contentdm.oclc.org/cdm/ref/collection/WesternWatersProject/id/9046 |
