HomeMy WebLinkAboutFile Documents.905 Chatfield Rd.0111.2018 (86).ARBK
An Employee-Owned Company
1517 Blake Avenue, Suite 101
Glenwood Springs, CO 81601
Telephone (970) 945-8676
Fax (970) 945-2555
Land Surveying Civil Engineering
January 25, 2019
Mike Horvath, P.E.
Civil Engineer II
City of Aspen Engineering Department
130 S. Galena Street
Aspen, CO 81611
RE: Permit No. 0111.2018.ARBK, 905 Chatfield Road
Response to Engineering Comments dated December 12, 2018 and various City
Comments
Dear Mike:
High Country Engineering, Inc. is providing responses to comments dated December 12, 2018
emailed on December 12, 2018. Your original comments are included below with my responses
in italics. In addition to our written responses, we are also including the revised drainage report
and civil engineering plans to provide the requested information.
12/12/2018 Engineering Comments
1. Project cannot propose trees within the utility easement.
The tree in the south easement is moved out of the easement.
2. Please regrade driveway to increase cover over water line. Insulation will not be accepted
in this case.
Per discussions with City Engineering and Water Department personnel, the
minimum resulting cover must be 6.0’ or greater. The plans are revised to identify
the proposed potholing. The contractor shall pothole and document existing
elevations of the water main and maintain 6.0’ minimum cover in all locations. See
Sheet C1-01 for the existing water main profile based on the best information
available estimated from above ground. See Sheet C1-10 for the driveway centerline
profile crossing the existing water. Specific notes are included providing instructions
for potholing, verifying existing depth, City inspection, and potential driveway design
with maximum 12.0% slope.
In the event the 9.57% driveway design on Sheet C1-10 and utility profile on Sheet
C1-01 does not achieve 6.0’ cover across the driveway cut, the contractor shall notify
High Country Engineering to provide an alternative design.
3. 3:1 is maximum allowable slope unless permanent erosion control is proposed. Please
adjust plans.
Complete. See Sheet C1-10.
4. Trees cannot be proposed on top of water main. Please provide 10’ separation between
proposed trees and water main.
02/14/2019
Mike Horvath
January 25, 2019
Page 2
Coordination with Lift Studio and City Engineering resulted by revising trees in the
front easements and allowing new trees in the front yard utility easement to be 10’
from the water main and are not placed on top of other utility services.
5. Please increase cross slope to be larger than longitudinal slope to ensure runoff reaches
swale.
Cross slope is revised to ensure runoff reaches swale by increasing slope to south and
east direction. See Sheet C2-00.
6. Leveling mechanism is required. No point discharges are allowed. Also a flow control
measure needs to be implemented to ensure runoff is not greater than historical.
Riprap is provided at the 4” underdrain outfall to dissipate drainage and prevent
point discharge. The bioretention pond is designed to detain the 100-year runoff
volume and WQCV which also treats runoff through rain garden growing media,
filter material, and underdrain. Peak runoff flow rates exceeding the 100-year rate
will be conveyed via the concrete outlet weir. Refer to Bioretention detail and 100-
year storage and WQCV WSE on Sheet C3-00. The elevations of the detail are
reflected on the Grading and Drainage Plan C2-00. An outlet orifice designed to
restrict the peak outflow to historical rates has been added to the underdrain outlet
piping.
7. Patio is impervious and runoff must be routed to BMP’s. Please clarify conveyance to
BMP’s for this patio.
A drain inlet is added to capture runoff from the master patio and convey drainage to
water quality and detention vaults.
8. COA requires a 20’ stick of C900 to be centered at water crossing. Please adjust plans to
incorporate this requirement.
Complete. See Sheet C1-01.
9. Please label vertical separation. 18” minimum.
Complete. See Sheet C1-01.
1/9/2019 Parks Comments
1. Do not place SCF in the driplines of trees.
Sediment control fences are revised accordingly out of driplines. See Sheet C2-00.
2. KEEP ALL STORMWATER PIPING OUT OF DRIPLINES OF TREES! KEEP ALL
UTILITIES OUT OF DRIP LINES OF TREES.
Stormwater piping and utilities are revised to the greatest extent possible out of the
driplines. See Sheet C2-00. Should conditions in the field differ from the plans, the
contractor understands any excavation near existing trees shall be reviewed with City
Forester.
3. Keep drainage swale out of tree driplines.
Drainage swales are revised to the greatest extent possible out of the driplines. See
Sheet C2-00.
02/14/2019
Mike Horvath
January 25, 2019
Page 3
I hope you find our responses to be complete. Please let me know if you have questions or
comments. Feel free to contact me if you require any additional information.
Sincerely,
Romeo Baylosis, P.E.
Project Manager
Enclosure
02/14/2019