United States
Environmental Protection
Agency
Environmental Research
Laboratory
Duluth MN 55804
^* 3;
Vy"-*
'/^,x'
vvEPA
Research and Development
EPA-600/S3-82-071 Oct. 1982
Project Summary
Spring and Springbrook
Fauna of the Piceance Basin,
Colorado
Robert J. Martinson, Elizabeth A. Sergey, and James V. Ward
The aquatic macroinvertebrates of
Willow Creek, Piceance Creek, Stew-
art Gulch, and of spring sources
surrounding Tract C-b (see map.
Figure 2) in the Piceance Basin were
sampled from July 1978 through
August 1980 as part of a baseline
monitoring program prior to oil-shale
development. The spring sources
exhibited a somewhat different and
more constant physical and chemical
environment than the streams. The
more constant conditions in the
springs allowed a generally greater
density and biomass of macroinver-
tebrates than did the other study
streams. Species compositions were
also different. Differences in the
macroinvertebrate community struc-
ture at each of the sites in the streams,
were apparently caused by differences
in flow patterns, substrate type, and
influence of spring sources. The spring
sources had distinct communities
despite generally similar environ-
mental conditions. Different slopes of
the springs were the eminent cause of
macroinvertebrate differences be-
tween springs. A discussion of major
potential impacts resulting from
development of oil-shale upon aquatic
macroinvertebrates in springs and
springbrooks surrounding mining
Tract C-b is presented.
This Project Summary was devel-
oped by EPA's Environmental Research
Laboratory, Duluth, MN, to announce
key findings of the research project
that is fully documented in a separate
report of the same title (see Project
Report ordering information at back).
Introduction
The objectives of this study were:
1. To determine the macroinvertebrate
community structure of spring sources
and spring brooks surrounding Oil-
Shale Tract C-b.
2. To provide baseline data from the
above habitats prior to oil-shale
development.
3. To continue monitoring Piceance
Creek above and below Tract C-b.
The Piceance Basin is located in
northwestern Colorado, northwest of
the city of Rifle, and southwest of the
city of Meeker (Figure 1). The basin is
characterized by north to northeast-
trending ridges and valleys. Elevations
in the study area range from 1900 to
2100m with local reliefs of over 100 m.
The area is semi-arid; total annual
precipitation ranges from 30 to 51 cm.
The temperatures range from -40°C to
+40°C.
Natural vegetation of the valleys and
slopes consists primarily of big sage
brush (Artemesia tridentata), which
forms associations with grasses, forbs,
or other shrubs. The ridges and north-
facing slopes are dominated by a pinyon
(Pinus edulis) — juniper (Juniperus
osteosperma and Juniperus scopulorum)
woodland. Although hay is grown on
irrigated land in the stream valleys,
plant coverage for the entire basin
averages only 25% of the land's surface.
-------
Drainage
Basin Boundary
N
t
Rifle
•
10km
Figure 1. Location and boundaries of the Piceance Basin.
The largest known oil resource in the
world lies in the oil-shale deposits of the
Green River Formation in Colorado,
Wyoming and Utah. This resource has
stimulated governmental and industrial
interest in developing oil-shale extraction
technology. In 1974, the U.S. Depart-
ment of the Interior leased two tracts of
public land in the Piceance Basin to
stimulate oil-shale development (Tracts
C-a and C-b). The present study was
concerned only with springs and streams
near Tract C-b. Numerous studies of the
macro!nvertebrate fauna in aquatic
habitats near Tract C-b have been
carried out, but very little work has been
done in springbrook habitats near the
tract.
The effect of area springs in providing
important water quality characteristics
to streams is recognized. The water
flowing from these springs is provided
by two main aquifers which are sepa-
rated by a 30-m confining layer termed
the Mahogony Zone. The upper aquifer
is primarily within the Unit Formation
(sandstones and malstones), which
forms the surface rock. The aquifier is
located in the Parachute Creek Member
of the Green River Formation. The lower
aquifer is highly saline (up to 30,000 mg
L"1 T.D.S.) principally due to nahcolite
(NaHCOa). The Mahogony Zone sepa-
rates the upper and lower aquifers both
chemically and hydraulically, except in
recharge and discharge areas. Re-
charge areas are generally above an alti-
tude of 2130 m; water discharges from
the upper aquifier to the alluvium of the
valley floors and through springs along
the valley walls.
The springs and springbrooks provide
excellent locations to monitor ground-
water quality as oil-shale development
proceeds. The development plan at
Tract C-b was changed from the Tosco II
process to a modified in-situ extraction
method. The new technique involves
mining 10 to 30% of the shale to create
retort chambers. The remaining shale
above the chambers is then fractured
and retorted in place. This process is to
be carried out in the Mahogony Zone.
The locations of the sampling sites of
this study are shown in Figure 2. WC-2
was approximately 1-m wide, 10-cm
deep, and had a rubble substratum. WC-
1 was similar in depth; however, it was
wider and had a sand-silt substratum.
There were some emergent macrophytes
at WC-1 (Rorippa nasturtium-aquaticum
and Veronica salina), but WC-2 was
limited to a small amount of submerged
macrophytes (Zannichiellia palustris).
SP-1 was approximately 1.5-m wide;
depth was variable (2 to 15 cm)
depending upon the amount of emergent
macrophyte growth. The substrate was
primarily rubble. SP-2 formed a small
pool below the emergence area due to
low gradient. The entire channel
became choked with macrophytes
during the summer, and the low
gradient allowed an accumulation of silt
except at the emergence area. The
macrophytes influenced water depth to
a greater degree than at SP-1 In
contrast, the substrate of SP-3 was
rubble-boulder. Width near the multiple
sources was approximately 5 m; depth
was not influenced by macrophytes,
though macrophyte growth was heavy
during the summer.
PC-1 and PC-2 were approximately 4
to 5-m wide. PC-1 had a cobble
substrate and little algal growth. PC-2
had a predominantly rubble-boulder
substrate which supported large mats of
algae (mainly Cladophora) during the
summer.
SG-1 was located approximately 100
m below the springs which provided
year-around flow to Stewart Gulch. The
site was about 0.5-m wide and supported
fairly dense growths of emergent
macrophytes. The substrate was pri-
marily silt-gravel.
The variability of physico-chemical
factors at or near a spring source is
compared to the lotic environment some
distance from the source. Springs are
generally rich in carbon dioxide due to
the breakdown of subterranean organic
matter by microorganisms, and have a
low pH as the excess carbon dioxide
forms a weak acid. Dissolved oxygen is
also usually low at spring sources.
Spring sources generally, contain
fewer species of macroinvertebrates
-------
Scandard
Gulch Tract C-b
WC-2
lSG-1
I
West Fork
Middle Fork
Figure 2. Locations of the sampling stations surrounding Tract C-b, in the
Piceance Basin, Colorado.
compared to downstream areas that
have greater physico-chemical variabil-
ity. This may be due to temperature,
dissolved oxygen, or other parameters,
which, being relatively constant, fail to
provide cues necessary for initiation or
completion of the life cycles in some
species. Species able to withstand the
unique conditions of a spring are likely
to have reduced competition and may
exhibit greater density and biomass
than at areas farther downstream. The
diversity and number of organisms
inhabiting spring communities resemble
communities located in areas of organic
enrichment, a situation also reported
below hypoliminal release reservoirs
(which in some ways resemble springs).
Physical and chemical variables were
tabulated over a two-year period.
Dissolved oxygen, free COz, pH, temper-
ature, and stream width and depth were
measured in the field. Samples for
analysis of bound COz, dissolved and
suspended solids, nitrate-oxygen, and
other ions were transported to the
laboratory on ice. Organisms from each
spring and stream source were preserved
in the field with 5% formaline and later
transferred to 80% ethanol. Biomass
was determined and species diversity
values were calculated using the
Shannon-Weaver Index.
Conclusions and
Recommendations
1. The spring sources exhibited more
constant physical and chemical
conditions and generally supported
greater numbers and biomass of
macroinvertebrates than sites in
Piceance Creek, Stewart Gulch, and
Willow Creek. The spring sources
had less dissolved and suspended
substances, and had less dissolved
O2 and lower pH than other locations
sampled.
2. The sites in Willow Creek, Piceance
Creek, and Stewart Gulch had quite
different physico-chemical conditions
resulting in different macroinverte-
brate communities. The major regu-
lating variables appear to be flow
patterns, substrate type, and proxim-
ity to spring sources.
3. The three study springs were similar
in most physical and chemical
variables measured, yet contained
distinct macroinvertebrate commun-
ities. Differing gradients allowed the
development of such communities.
4. Monitoring of springbrook macroin-
vertebrates and physico-chemical
variables (especially dissolved salts
and flow) should be continued as oil-
shale development proceeds.
5. Additional research is necessary
concerning substances contained in
spent oil-shale from the modified in-
situ process and their effects upon
aquatic macroinvertebrates.
0 US. GOVERNMENT PRINTING OFFICE. 19K-559-017/0846
-------
Robert J. Martinson. Elizabeth A. Bergey, and James V. Ward are with the
Colorado State University, Fort Collins, CO 80523.
Leonard Mueller is the EPA Project Officer fsee below).
The complete report, entitled "Spring and Springbrook Fauna of the Piceance
Basin, Colorado,"(Order No. PB 82-240 193; Cost: $7.50, subject to change)
will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Research Laboratory
U.S. Environmental Protection Agency
Duluth, MN 55804
I 1
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
------- |