HomeMy WebLinkAboutLand Use Case.605 S Alps Rd.13A-87 MEMORANDUM
TO: Aspen Planning and Zoning Commission
FROM: Glenn Horn, Assistant Planning Director
RE: Moses 8040 Greenline Review
DATE: June 16, 1987
BACKGROUND INFORMATION
Applicant: Gaard Moses
Applicant's Representative: Gideon Kaufman
Location: South of the Aspen Alps just to the east of Little Nell
ski slope (see attachment 1)
Zoning: R -15 PUD
Size: 1 acre (43,560 square feet)
APPLICANT'S REQUEST
The applicant is requesting 8040 Greenline Review approval in
order to reconstruct a single - family house on the subject site.
PREVIOUS P &Z REVIEWS
On January 28, 1987 the P &Z reviewed a request from this appl-
icant for rezoning from C (Conservation) to R -15 PUD and a
subdivision exception for the purposes of creating two lots. The
P &Z recommended approval of the applicant's request and the City
Council subsequently granted approval to the applicant. At the
City Council meeting the applicant indicated that it was his
intention to return to the P &Z in the Spring to go through a 8040
Greenline review to reconstruct one of the dwelling units on the
site.
REFERRAL COMMENTS
1. Engineering Department: Due to an unusually substantial
work load the Engineering Department was not able to
provide the Planning Office with written comments
concerning this application. However, Jay Hammond has
reviewed a geological report prepared by Chen &
Associates regarding the Moses property and met with
the applicant (see attachment 1, Chen report). Based
upon Jay's review of the report and discussions with
the applicant he has made the following two recommenda
tions:
a) Mitigation measures such as deflection walls and
berms should be constructed on the east side of
the proposed dwelling to protect the residence
from the possibility of a mud flow.
b) Additional studies of the potential for a large
mud flow should be undertaken to the satisfaction
of the City Engineer prior to a date established
by the P &Z.
PLANNING OFFICE COMMENTS
Section 24 -6.2 of the Municipal Code establishes specific review
criteria for 8040 Greenline review. This section lists the
criteria and addresses each of them individually.
1. Criteria - Whether there exists sufficient water
pressure and other utilities to service the intended
development.
Response - The development is presently served by the
local sanitation district and service is adequate, the
development presently utilizes a well, however, as part
of the subdivision exception process approved this
winter, the applicant agreed to connect to the City of
Aspen water system.
2. Criteria - The existence of adequate roads to insure
fire protection, snow removal and road maintenance.
Response - During review of the subdivision exception
it was established that roads serving the site are
adequate.
3. Criteria - The suitability of the site for development
considering the slope, ground instability and possi-
bility of mud flow, rock falls and avalanche danger.
Response - About one month ago there was a minor mud
flow on the subject property. Although the mud flow
did not disturb the proposed building site it did come
close enough to cause us to look closely at the
potential for a larger mud flow. The City engineer has
commented above concerning the geologic report concern-
ing the mud flow which was filed by the applicant. The
Planning Office supports the view of the City Engineer.
4. Criteria - The effects of the development on the
natural watershed, runoff, drainage, soil erosion and
2
consequent effects on water pollution.
Response - The site plan for the proposed development
calls for the new residence to approximately match the
existing building footprint. Therefore, it is not
anticipated that there will be any adverse effects on
the surrounding environmental features in the area.
5. Criteria - The possible effects on air quality in the
area and city wide.
Response - There will be no adverse effects on local
air quality resulting form this development.
6. Criteria - The design and location of any proposed
structures, roads driveways or trails and their
compatibility with the terrain.
Response - The location of the structure will not be
altered significantly. Due to the isolated location of
the building site, the residence will not be highly
visible from off the site. Roads serving the site will
not be relocated.
7. Criteria - Whether proposed grading will result in the
least disturbance to the terrain„ vegetation and
natural features.
Response - There will be very little disturbance to the
terrain on the site, with the exception of the con-
struction of a berm on the east side of the property
which is intended to protect the property from a
potential mud flow.
8. Criteria - The placement and clustering of structures
so as to minimize roads, cutting and grading and
increase the open space and preserve the mountain as a
scenic resource.
Response - In our opinion, the existing house is
located on the ideal location on the subject site. The
building site is relatively flat and out of site from
neighboring properties.
9. Criteria - The reduction of building height and bulk to
maintain the open character of the mountain.
Response - As mentioned already due to the excellent
citing of the house, the design and size of the
structure is not of great significance to this review.
The house is restricted to 3,800 square feet in size.
3
RECOMMENDATION
It is our opinion that the most significant issue associated with
this application is the potential for another mud flow affecting
the site. Based upon a site visit made by the Planning Office
and City Engineer, it does not appear likely that there will be a
mud flow which will affect the proposed residence. However, the
Chen report leads us to believe that more definitive information
should be provided before the final building plans are approved.
Therefore, the Planning Office recommends approval subject to the
following conditions.
1) All representations made by the applicant will be
adhered to.
2) Mitigation measures such as deflection walls and berms
should be constructed on the east side of the proposed
dwelling to protect the residence from the possibility
of a mud flow.
3) Additional studies of the potential for a large mud
flow should be undertaken to the satisfaction of the
City Engineer prior to the issuance of a building
permit for the proposed reconstruction of the dwelling
unit.
Moses8040 /gh
4
5080 Road 154 Casper
Chen &Associates Glenwood Springs, CO 81601 Colorado Springs
Consulting Geotechnical Engineers 303/945 -7458 Denver
Fort Collins
Rock Springs
Salt Lake City
San Antonio
May 27, 1987
Subject: Potential Geologic Hazards
Reconnaissance for the
Gaard Moses Property,
Aspen, Colorado.
Job No. 4 194 87
Mr. Gaard Moses
P.O. Box 21
Aspen, Colorado 81612
Dear Mr. Moses:
This letter summarizes the findings of a geologic hazards
reconnaissance made for the Gaard Moses property. The purpose of
the reconnaissance was to observe the geologic conditions in the
vicinity of the site and to identify conditions which could have
an adverse impact on the construction of a new residence at the
location of the existing house. The investigation consisted of a
field reconnaissance and review of published geologic literature.
Site Conditions:
The Moses property consists of an irregular-shaped
ated parcel
which covers about 0.5 acres. The property
South Alps Road, Aspen, Colorado. The property is on the lower
slopes of Aspen Mountain. Terrain at the site is very steep with
slopes of about 40% to 50 %. A two -story wood frame house
occupies the lower northern part of the property. A single -story
wood frame house occupies the lot to the west and the Aspen Alps
condominiums are located further west. The hillside in the
vicinity of the proposed building site is generally forested with
dense stands of aspens and conifers. The channel of Spar Gulch
parallels the eastern property line and is located about 25 feet
east of the existing house.
Proposed Construction:
The existing house will be razed and a new residence
constructed at the same site. The new residence will be a one -
to two -story wood frame structure without a basement. Specific
structure and grading plans for the new home have not been
developed. It is our understanding that the new construction
will not require substantial site grading.
Mr. Gaard Moses
May 27, 1987
Page .2
Evaluation:
Based on the findings of this investigation there are several
conditions of a geologic nature which should be considered.
Building Foundation: We do not anticipate difficult
foundation conditions. After the existing house is razed a site
specific subsurface investigation should be conducted to evaluate
ground -water conditions, bearing capacity and potential volume
change characteristics of the foundation soils.
Slope Instability: The slopes in the immediate vicinity of— po L
the existing house and the proposed new residence appear to be P laces
stable under present environmental conditions; however, grading 11
of the steep slopes could result in local instability,
particularly if ground -water seepage is encountered.
A local landslide occurred this spring upslope of the
building site in an area of active springs. The landslide is
located near the southern part of the property about 180 feet to
the south of the existing house. Debris from the landslide were
mixed with spring water discharge and traveled as a small debris
flow in the Spar Gulch channel. Some of the debris were
deposited near the existing house. Some debris were transported
further downslope and were deposited on the Chance property.
As with all construction on steep mountain slopes there is
some risk of slope failure. Since substantial grading is not
anticipated for the new construction the impact of the
construction on slope instability is considered to be low.
Preliminary grading plans should be reviewed by a geotechnical
engineer prior to final design and construction at the site.
Slope instability at the site could also be related to grading on
adjacent properties. Grading on adjacent properties should be
evaluated prior to construction.
Debris Flow And Flooding: The localized landslide which
occurred upslope of the proposed building site this spring
resulted in a small debris flow. The bulk of the debris were
confined to the channel of Spar Gulch; however, some debris were
deposited on the property. These debris did not reach the
existing house.
In our opinion there is a potential for larger debris flow $
uc
along Spar Gulch. Additional studies should be undertaken to--2
determine the probable debris flow and water flood impacts. The sx, .
water flood and debris flow evaluations will require the services
of a surface water hydrologist who is familiar with the local l
drainage conditions and the city's master drainage plan. epJEeey'
Mitigation measures such as deflection walls and berms may be
Chen &Associates
aw,
Mr. Gaard Moses
May 27, 1987
Page 3
required to protect the new residence. Any flood or debris flow
mitigation measures for this site should be coordinated with
other property owners along the Spar Gulch drainage way. The
mitigation measures should be compatible with the city's master
drainage plan. We are available to assist the surface water
hydrologist in evaluating the debris flow aspects of the drainage
evaluation.
Abandoned Mines: Review of the extent of mining map by
Bryant, 1972, and general mining maps of the Aspen district in
our files show that the site may be underlain by abandoned mine
workings. If uncaved stopes or mine portal are present near the
building site then there may be a potential for damaging mine
subsidence. This potential should be assessed by further
studies.
We recommended the additional studies consist of an inventory
of available mine maps showing the extent of mining in the
area. The location of the site with respect to the mine workings
should be determined using surveys from identifiable surface mine
features such as the Lower Durant Tunnel portal. The locations
of the workings indicated by these reviews can then be used to
assess the subsidence potential.
Limitations:
This report has been prepared in accordance with generally
accepted geotechnical engineering practices in this area for use
by the client for preliminary site evaluations. As indicated,
several conditions were present which warrant further investiga-
tion prior to design and construction.
If there are any questions concerning this report or if we
may be of further service, please let us know.
Sincerely,
L. aJ0\srq1' CHEN & ASSOCIATES, INC.
15222 .:*
1 �o By h:., °. a-� 1/.� �
r 4 Ral y G. Mock,
st`•T' ”oNptt ,, •O�
°•. . g
E n ineering Geologist
eg ,.•�4
RGM /rrb
Rev. By: S.L.P.
Chen &Associates
References
Bryant, Bruce, 1972, Mine Locations and Metal Production, Aspen,
Colorado:
U.S. Geol. Survey Map I- 735 —D.
Chen &Associates
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LAW OFFICES
GIDEON I. KAUFMAN -�
A PROFESSIONAL CORPORATION
BOX 10001
315 EAST HYMAN AVENUE. SUITE 305
ASPEN. COLORADO 81611 TELEPHONE
GIDEON I. KAUFMAN AREA CODE 303
925-0188
RICHARD S. LUHMAN April 23, 1987
Mr. Glen Horn,
Associate Planning Director
Aspen /Pitkin County Planning Office
130 S. Galena Street
Aspen, Colorado 81611
Re: 8040 Greenline Review /Lot 1, Moses Lot Split
Dear Glen:
Please consider this letter an application for 8040
Greenline review pursuant to Section 24 -6.2 of the Zoning
Code of the City of Aspen. The application is submitted on
behalf of Gaard Moses who seeks to comply with the
commitments he made in the recent rezoning and subdivision of
his property. This application deals with Lot 1, Gaard's
home, and its conversion to single - family residential use
with a floor area not to exceed 3,800 square feet.
The plans for modification of the existing structure are
being prepared by Bill Poss within the parameters of the
building footprint on the Conceptual Design Study submitted
herewith. We believe that, because this conversion only
slightly modifies the existing structure, it fully complies
with the intent of Section 24 -6.2 in minimizing additional
impacts to this transition area. In fact, the conversion of
this structure to single - family will, in the long run, not
merely minimize impacts but reduce them through the less
intensive resulting use. The criteria set forth for
Greenline review are all met in this particular situation:
1. The existence of sufficient water pressure is
guaranteed by the applicant's agreement to implement the
water connection plan shown on the final subdivision plat as
contained in the Subdivision Exception Statement recorded in
connection with the plat. This plan involves running
approximately 400 feet of pipe to connect with the City's
high pressure water main located in the nearby ski slope.
2. Submitted herewith is a letter dated April 2, 1987
from Wayne L. Vandemark, Fire Marshall, indicating sufficient
fire access to the Moses' residence. Snow removal and
maintenance of the Aspen Alps road is adequately provided by
private contract.
Mr. Glen Horn
April 23, 1987
Page 2
3. The structure which we have proposed to modify has
been located on this former railroad roadbed for
approximately thirty years without problems from ground
instability, mud or rock slides, and avalanches. The
proposed modifications are quite minor and suggest no
impacts.
4. This project's modest modifications to the existing
structure will have no effects on the natural watershed
runoff, drainage, soil erosion and consequent water
pollution.
5. The possible effects on air quality in the area and
City wide will be only those resulting from construction
during the remodeling and should actually improve in the long
run due to the reduction in use of this structure.
6. The design location of the proposed structure,
roads, driveways or trails will not be significantly amended.
The upgrade of the structure will involve the use of
materials compatible to the surroundings and result in a much
more esthetically pleasing structure.
7. Other than the introduction of some additional
foundation walls very close to the structure there will be no
disturbance to the terrain, vegetation or any natural land
features. This is more fully addressed in Bill Poss' letter
submitted herewith.
8. As you have observed, the existing residential
structure is located in the ideal building site from the
public's perspective in that the site is a pre- existing
railroad roadbed and quite flat. For this reason, the slight
modifications of the structure's footprint disclosed by the
site plan being submitted herewith minimize the impact on
this already developed site. There will be no impact from
roads which are already in existence and no further cutting
or grading to disturb the existing natural terrain.
9. The Conceptual Design Study which is submitted
herewith discloses the extent by which the roof plan of this
structure is to be modified. The existing structure is
constructed on a pre- existing railroad roadbed which is below
the natural grade of the property and which enhances and
minimizes any impact of this modification on the well
forested existing natural slope of the mountain. In fact,
the actual site is located over 70 feet below the Little Nell
ski slope to the west and for years (until the Gondola was
constructed) few people in the community even realized that
the property was developed. While the property is now
visible from the gondola that overhead viewplane will remain
relatively unaffected by the proposed modifications and, if
anything, improved esthetically by the upgrading of the
structure which the applicant seeks permission to accomplish.
Mr. Glen Horn
April 23, 1987
Page 3
Enclosed are the items mentioned above together with our
application fee, a pre- addressed envelope to be used to
notify the Aspen Alps of the Greenline review date together
with the fees for processing this application. While I
believe you will find the enclosed in order I would
appreciate your contacting me to discuss any concerns you may
have with them. Otherwise, I look forward to having this
placed on the next available agenda. Naturally, I appreciate
and wish to thank both you, the Planning Office and the
Planning and Zoning Commission for their consideration and
help in this matter.
Very truly yours,
LAW OFFICES OF GIDEON I. KAUFMAN,
a Professional Corporation
By /J�
Gid n Kaufman
GK:bsr
Enclosures
Agil -00•014
t.,
1
605 EAST MAIN STREET
ASPEN. COLORADO 81611
TEL. (303) 925 -4755
April 28, 1987
Messrs. Gideon Kaufman
and Richard Luhman
1:15 East Hyman Avenue
Aspen, Colorado 81611
Gentlemen:
Attached is a copy of the conceptual design study for the
Moses remodel.
Briefly, our concept is to remove the upper story of the
existing structure, replace it with a new design for the
upper level, and create a new roof structure.
The new structure will be within the existing clearing,
approximately over the existing structure, which will -
rninirnize the impact to existing vegetation and grading.
The program calls for expanding the structure to the south at
the second level over an existing graded embankment, and to
the north with decks to cover some existing parking.
I will keep you informed as the designs develop. If you have
any questions, please don't hesitate to call.
Sincerely,
13 11 Rocs
BP: dem
Enclosure
April 2, 1987
To Whom It May Concern:
The Aspen Fire Department does have access to the G. Moses
residence on Aspen Alps road.
id4; edX
Wa ne L. Vandemark
Fire Marshal
ASPEN /PITRIN PLANNING OFFICE
130 S. Galena Street
Aspen,
(303) 925 -2020
Date:
I� j
Dear
This is to inform you that the Planning Office has completed its
preliminary review of the captioned
ti ned complete. ication. We have determined
that your application LI c
Additional items required include:
Disclosure of Ownership (one copy only needed)
Adjacent Property Owners List /Envelopes /Postage (one copy)
Additional copies of entire application
Authorization by owner for representative to submit applica
tion
Response to list of items (at ached /and below) de of the
compliance with the applicable policies
Code, or other specific materials
A check in the amount of $
A. Your applicatio4 s� complete and we sc� /uledWetw or ill
review by the he
to that
date you e. Several days need any iordaolyour hearing, we will call and
matp
available a copy of the memorandum.. Please note that it
IS NOT your responsibility to post your property with a
sign, which we can provide you for a $3.00 fee.
B. Your application is incomplete, we have not scheduled it
requested, this
e will place When
ou on receive have
agenda.
questions, 4
If you have any q , please call
the planner assigned to y our case.
Sincerely,
4SPEN9_ITRIN PLANNING OFFICE
C_�