Emigration Creek TMDL
Emigration Creek, 2002.
Emigration Creek is a 3rd order tributary of the Jordan River supporting: 2B-Non-contact recreation and 3A-Coldwater fishery beneficial uses.
Instream Flow
The hydrologic cycle for the Emigration Watershed is short, with snow pack disappearing by early April at 6,300 ft. elevation. Seasonal peak flows (March-June) have been as high as 140 c.f.s., with seasonal low flows averaging 10 c.f.s. The Flood Control & Engineering Division of Salt Lake County monitors Emigration Creek flows on a daily basis at the canyon mouth. These records can be accessed through Salt Lake County Streamflow and Rainfall Historical Data.
Emigration Creek Water Quality
Monitoring efforts by the Salt Lake County 208 Water Quality Project, Salt Lake City-County Health Department, Salt Lake City Public Utilities, University of Utah, Salt Lake County Public Works, and U.S. Geological Survey suggest that the potential origin of non-point pollution in the Creek includes animal feedlot or grazing areas, residential waste disposal, urban stormwater runoff, hydrologic modifications, and groundwater seepage from old holding vaults and septic tank leach fields. Additionally, watershed Management Plans prepared by Salt Lake County (1996) and Salt Lake City (1988) make the following observations in regard to water quality in Emigration Canyon:
"Water quality in Emigration Canyon is the poorest of all the watersheds. Although Emigration Creek water is currently not used for culinary purposes, Salt Lake City owns two-thirds of the water rights and its use in the future remains an option. The City has refused sewer line access because Emigration Canyon is not within City boundaries. Anexation of the canyon has been controversial and forestalled for more than [two] decades. The watershed management plan recommends the City make an exceptio to its policy and grant sewer access."
In 2002, Salt Lake County conducted a water quality assessment of Emigration Creek and found high fecal coliform levels. This data was published in 2003 in the Emigration Watershed Non-Point Pollution Assessment: Coliform Bacteria Water Quality Analysis.
Emigration Canyon
The Emigration Canyon Watershed has been designated a National Historic Place, as the route used by early pioneers who entered the Salt Lake Valley in 1848. The Watershed comprises about 18 square miles with an estimated lenth of 10.5 miles. it contains 32 first order tributaries geomorphically classified as steep "A-2" channels, while the second order Emigration Creek is principally a "B-3" stream type. Average annual discharge is estimated between 4,400-6,110 acre feet, comprising about 2-3% of the total Wasatch Front water source for the Jordan River Watershed.
Population
Since 1980, the population in the canyon has doubled. Present population is estimated at 1,238 with an average family size of 2.8 and a median age of 35.4 years. By the year 2010, the population is projected at 2,000 with water suppply as the main constraint to development.
Land Ownership
Approximately 4,800 acres or 40% of the total watershed is privately owned. The remainder is publicly owned or managed either by the U.S. Forest Service (34%) or Salt Lake City Corporation (26%). Lots in Emigration Canyon are dominated by single family residential use, there are 1,136 lots of record in the canyon, of which 440 have been developed. Of the 696 lots remaining, 340 could be developed due to slope, access, stream buffer, and ridge line restrictions. Of the 11,520 acres in the watershed, about 10% is subdivided.
Soils
The Summit Soil Survey (Soil Conservation Service, 1974) indicates the predominate stream-side soil types to be represented in the Harker Series, which has the following sever constraints: High shrink-swell potential, very high to high erosion hazard, slow to very slow permeability, high water runoff potential, susceptibility to hillside slippage. Other limiting soil types (generally constrained by rock outcrop or shallow bedrock) occur in upper reaches (Pincrest Are) of the watershed.
Geology
Formations prominent in the upper watershed include limestones and sandstones of the Thaynes, Ankereh, Woodside, and Park City units. Dominant geology in the lower watershed is the Twin Creek limestone, Preuss Formation (red shale and sandstone), and Kelvin Formation (reddish brown silt, sandstone, and conglomerate).
Wastewater Disposal
All existing and new development is required by State law to provide individual septic tank drain fields and holding vaults. The Salt Lake Valley Health Department is charged with responsibility for regulating these facilities for compliance with State laws governing groundwater contamination and source water protection. The State Division of Water Quality presently does not consider urban stormwater runoff as "wastewater" but does require that best management practices (mainly erosion and runoff controls) be implemented during both construction and post-construction phases.
December 30, 2005 Update
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