9342

• UCREFRP Catalog Number: 9342
• Author: Wynn, K. H., N. J. Bauch and N. E. Driver.
• Title: Gore Creek Watershed, Colorado--Assessment of Historical and Current Water Quantitiy, Water Quality, and Aquatic Ecology, 1968-98.
• USFW Year: 2001.
• USFW - Doc Type: Denver.
• Copyright Material: NO

Gore Creek Watershed, Colorado-Assessment
of Historical and Current Water Quantity, Water
Quality, and Aquatic Ecology, 1968-98

By Kirby H. Wynn, Nancy J. Bauch, and Nancy E. Driver

Abstract

The historical and current (1998)
water-quantity, water-quality, and aquatic-
ecology conditions in the Gore Creek water-
shed are described as part of a study by the
U.S. Geological Survey, done in cooperation
with the Town of Vail, the Eagle River Water
and Sanitation District, and the Upper Eagle
Regional Water Authority. Interpretation of
the available water-quantity, water-quality,
and aquatic-ecology data collected by various
agencies since 1968 showed that background
geology and land use in the watershed influence
the water quality and stream biota.
Surface-water nutrient concentrations
generally increased as water moved down-
stream through the Town of Vail, but concen-
trations at the mouth of Gore Creek were
typical when compared with national data for
urban/undeveloped sites. Nitrate concentrations
in Gore Creek were highest just downstream
from a wastewater-treatment plant discharge,
but concentrations decreased at sites farther
downstream because of dilution and nitrogen
uptake by algae. Recent total phosphorus concen-
trations were somewhat elevated when compared
to the U.S. Environmental Protection Agency
recommended level of 0.10 milligram per liter
for control of eutrophication in flowing water.
However, total phosphorus concentrations at the
mouth of Gore Creek were relatively low when
compared to a national study of phosphorus in
urban land-use areas.

Historically, suspended sediment
associated with construction of Interstate 710
in the early 1970's has been of primary concern;
however, recent data indicate that streambed
aggradation of sediment originating from
Interstate 70 traction sanding currently is
a greater concern. About 4,000 tons of coarse
sand and fine gravel is washed into Black Gore
Creek each year following application of traction
materials to Interstate 70 during adverse winter
driving conditions. Suspended-sediment concen-
trations were low in Black Gore Creek; however,
bedload-transport rates of as much as 4 tons per
day have been measured.
Water samples were collected during
spring and fall of 1997 from five alluvial moni-
toring wells located throughout the Town of Vail.
Nutrient concentrations generally were low in the
alluvial monitoring wells. Specific-conductance
values ranged from 265 to 557 microsiemens per
centimeter at 25 degrees Celsius. Concentrations
of radon in monitoring-well samples exceeded
the 300-picocuries-per-liter U.S. Environmental
Protection Agency proposed maximum contami-
nant level (which has been suspended pending
further review). Low levels of bacteria and
methylene blue active substances indicate
there is little or no wastewater contamination
of shallow ground water in the vicinity of the
monitoring wells and one of the municipal water-
supply wells. Ground-water ages in the alluvial
aquifer ranged from about 2 to about 50 years
old. These ages indicate that changes in land-
management practices may not have an effect
on ground-water quality for many years.

Abstriact