UTAH DEPARTMENT OF TRANSPORTATION
TO: Those listed Below
FROM: R. James Naegle, P.E. Engineer for Location and Environmental Studies
SUBJECT: Logan Canyon, U.S. -89 Study Biological Assessment
RECEIVED MAY 23 1987 CH2M HILL BOISE
DATE: May 19, 1987
Attached is a copy of the Biological Assessment done by
Stanley L. Welsh, Endangered Plant Studies, Inc., of Orem
The Maguire Primrose found in the project vicinity is
the object of the Biological Assessment.
If you have questions or comments, please contact John Neil
of our office at 965-4227. Thank you for your cooperation.
cc: Robert Ruesink, U.S. Fish & Wildlife
Daniel Dake, FHWA
Stan Nuffer, CH2M Hill
Eduardo Norat, UDOT
John Neil, UDOT
ENDANGERED PLANT STUDIES, INC.
129 North 1000 East
Orem, Utah 84057
18 May 1987
Mr. James R. Naegle, P.E.
UTAH DEPARTMENT OF TRANSPORTATION
4501 South 2700 West
Salt Lake City, Utah 84119 RECEIVED MAY 19 1987 241 Utah Department of Transportation Location and Environ. Studies
Dear Mr. Naegle:
This report is in response to your letter of 5 May 1987 delivered to EPS
from the Utah Department of Transportation on 7 May 1987 regarding a
biological assessment of a segment of the highway in Logan Canyon
(Project No. 1371163, FO; Authority No. 5988).
An on-site survey was conducted during the period May 11-12 on a segment
of the Logan Canyon highway adjacent to and east of the Wood Camp
Trailer Park to the vicinity of milepost 385, a distance of
approximately 1000 feet, and for another 1000 feet east of there to
assure coverage of a second population of of Maguire primrose (no. 5 of
the attached map).
Prior to the on-site survey a literature review was undertaken.
Specific references were sought concerning present knowledge of the
distribution of Primula maguirei, a species listed as threatened under
stipulations of the Endangered Species Act of 1973, as amended.
Literature reviewed included status reports by Welsh in 1979 and the
Utah Native Plant Society (Padgett 1987). The latter report is
summarized in an April 1987 report to the Utah Department of
Transportation by CH2M Hill, which was made available by your office.
The Maguire primrose is apparently a calciphile, restricted to Laketown
and Fish Haven dolomite formations. It js likewise a mesophyte, growing
where moisture is available at least through the flowering period, which
apparently is from early April to after mid-May. Plants in more arid
and exposed sites flower first, followed later by those of the more
protected and shaded areas.
Proposed highway modifications, alternatives 81, C1, and D1, were
considered. All are essentially within the area of concern for a
principal population (designated in reports as population 4) of the
Maguire primrose. The plant occurs on outcrops of limestone south of
the highway, beginning at a point approximately 700 feet west of
milepost 385 and extending east to a point approximately 350 feet west
of that milepost. The population, estimated to contain 176 clumps of
Maguire primrose (Padgett 1987), occurs in small aggregations on exposed
boulderlike outcrops at the west edge of the population. The initial
(westernmost) occurrences are about 40 to 50 feet above the highway, and
about that same distance south of the present road shoulder. Eastward
the limestone is exposed as a cliff-forming unit and the population is
largest in the area where it is most exposed to the highway, about 550
feet west of milepost 385. At that most developed and deeply shaded
exposure the plants occur in profusion, beginning at a point estimated
at about 30 feet above the existing road. Eastward the exposure trends
upward in elevation and the population follows that exposure to perhaps
a hundred feet above the roadway.
The second population in close proximity to the proposed modification
(population 5) begins some 400 or 500 feet to the east of the east end
of the area of concern. The plants are more remote from the highway and
the plants are more scattered. There does not seem to be any potential
impact of the present proposal on that population.
Three other plants were noted in the CH2M Hill report indicated above.
They are Erigeron cronquistii, Musineon lineare, and Penstemon
compactus. All are currently cited as Category 2 plants in the Federal
Register, indicating that they are possible candidates for future
listing processes. Of these species only Musinpon was noted within the
proposed construction site. The species is a common component of the
limestone cliffs plant communities in Logan Canyon. It is growing with
the Maguire primrose at the population 4 site. The proposed action is
not thought to constitute a significant threat to the Musineon or to the
other category 2 species.
Two concerns were stated in the CH2M Hill report for the Maguire
primrose, especially at population 4. Other populations (2, 3, and 6)
known for the species are considered by me to be too remote from the
construction site as to be threatened by the proposed action. The
concerns involve cold air drainage down Logan Canyon, and the moderating
effect of canyon bottom vegetation on adjacent cliffs serving to buffer
the existing populations of Maguire primrose. To these can be added a
third concern -- dust from construction activities. Dust might overlay
stigmas thus providing competition for pollination and reduced seed set.
Concern number one, cold air drainage, does not seem to be significant.
The drainage of cold air is expected to continue about as in the past,
regardless of highway modifications. The second concern is probably
more importart, but, it should be noted, that the best developed part of
the population of Maguire primrose at population 4 is on the most
exposed portion of the cliff system (i.e.', there is little or no
screening vegetetation between the population and the road). However,
in point of action all possible care should be given to prevention of
wholesale removal of the remaining screening vegetation. Only that part
of the canyon bottom vegetation absolutely in the way of construction
should be removed. The third concern, dust, can be mitigated by waiting
until the flowering period is over prior to commencement of construction
activities, i.e., construction should commence no earlier than June.
The nearest approach of the construction is at the bend of the road at
the westernmost edge of the population 4 site. It is understood that as
much as 10 feet of the toe of the ridge might have to be removed to
allow proper alignment of the roadway. This should cause no problem to
the population if the rockwork is undertaken i.-Ii th care. Blasting should
be kept at a minimum and proper barriers constructed as to prevent
uphill scattering of debris.
If the recommendations cited above are followed there should be minimal
or no impact to the Maguire primrose population 4. The other
populations will not be adversely affected.
With best regards,
Stanley L. Welsh President
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