HomeMy WebLinkAboutFile Documents.211 Cottonwood Ln.0062.2019 (2).ARBKEngineering_0062.2019.ARBK_1
Page: 3
Author: jackd
File Name: 530-003211CottonwoodDrainLtr-10-19-18.pdf
Provide more detail for how rain
barrels release water?
530-003211CottonwoodDrainLtr-10-19-18.pdf (5)
Page: 4
Author: jackd
File Name: 530-003211CottonwoodDrainLtr-10-19-18.pdf
Green roof maintenance needs
to be included in the
maintenance section.
Page: 4
Author: jackd
File Name: 530-003211CottonwoodDrainLtr-10-19-18.pdf
The pervious paver volume can
be used for detention.
Page: 7
Author: jackd
File Name: 530-003211CottonwoodDrainLtr-10-19-18.pdf
Green roof is viewed as
pervious, and up to the same
amount of impervious areas
draining toward green roof.
Page: 16
Author: jackd
File Name: 530-003211CottonwoodDrainLtr-10-19-18.pdf
Include a more detailed
description of a properly
operating system.
Mountain Cross Enginee
Civil and Environmental Consultin 826 ½ Grand Avenue, Glenwood Sp
P: 970.945.5544 F: 970.945.5558 www.mo
Due to the proactive effort to reduce impervious areas, propo
condition. Since the Smuggler Trailer Park is in an unresol
drain system is concerned, the City has required detention. T
from the FAA Procedure described in the Code. Due to the
historic condition, the detention volume that is required of 6
offset detention volume by providing rain barrels per the am
of 110 gallons, or 14.7 cubic feet. This would drop the deten
Because the site is small and detention would be impractica
lieu” of providing on-site detention. The calculations are atta
Provide more detail
for how rain barrels
release water?
Mountain Cross Engineering, Inc. Civil and Environmental Consulting and Design 6 ½ Grand Avenue, Glenwood Springs, CO 81601
eriodically for the drainage system. At a minimum the following
e spring and fall: swales, roof gutters, downspouts, and the water
ed and cleared of mud and debris. Temporarily, the general notes
quent inspection of the silt fence. Attached in the Appendix is a
e used by the Owner.
drainage design, WQCV was anticipated. The site grading was
e WQCV.
entire site by providing permeable pavers and green roof. These
aces. Green roof maintenance needs to be
included in the maintenance section.
211 Cottonwood Lane
October, 2018 Page 4 of 5 Water Quality The Code requires that Water Quality Capture Volume (WQCV) be provided. For the project, the permeable pavers are proposed to provide the WQCV. Downspouts from roof gutters should be directed onto the permeable pavers. The WQCV was calculated based on the site acreage and percent impervious area. Based on Fig
8.13 in the Urban Runoff Management Plan the watershed inches is determined based on the percentage of effective impervious area determined from the type of drainage system that is tributary to the impervious areas. Level 1 adjustment was used to determine the “Effective Impervious Area” from Fig 8.14. Based on the Effective Imperviousness of 51%, this yields 0.07 watershed-inches. Using the basin area of 0.122 acres, this yields 31.0 cubic feet of WQCV. The WQCV structure of permeable pavers is 925 square feet with 8” of sand assuming a 30% void ratio. This volume of the voids is 185 cubic feet which is much larger than the required volume.
If the capacity of the WQCV is exceeded, the excess runoff would overtop the curb and flow into the existing storm system in the adjacent Cottonwood Lane. Calculations are attached.
Temporary structures are intended to be used during construction activities. Temporary erosion control measures that are to be employed during construction have been designed to contain sediment on the site and to mitigate erosion from construction activities. Silt fencing is placed around the downhill limits of disturbance and inlet protection is placed at the storm drain on the street. Permanent erosion control measures are revegetation of disturbed areas, and design of
conveyances to prevent erosion. Additionally, the Code requires a Water Quality Capture Volume (WQCV) per the Figures 8.13 and 8.14. The site will disturb less than one acre and therefore will not require a permit from CDPHE. Maintenance
Maintenance will be required periodically for the drainage system. At a minimum the following should be done bi-annually in the spring and fall: swales, roof gutters, downspouts, and the water quality structure should be cleaned and cleared of mud and debris. Temporarily, the general notes require the maintenance and frequent inspection of the silt fence. Attached in the Appendix is a
The pervious paver
volume can be used
for detention.
Green roof is viewed
as pervious, and up
to the same amount
of impervious areas
draining toward
green roof.
Maintenance Plan
hecklist to aid the Property Owner of ongoing drainage system maintenance for
ne in Aspen CO. The site will require more frequent cleaning of sediment
e matures, maintenance should be performed after large magnitude rainfall
nging of the seasons. Damaged, cracked, or missing items should be repaired
overed. This is not intended to be an all-inclusive list:
ve drainage and grade any ponding areas to drain
ales from deposited sediment and debris
Include a more
detailed description
of a properly
operating system.
A description of rain barrel release has been added to page 3 of the report.
A product specification sheet has been added to plan sheet C5.
The maintenance for the Green Roof has been added to the maintenance section
and included in the Maintenance Plan.
The report has been revised to provide detention volume in the
permeable pavers.
The green roof and the permeable pavers are considered as 50% impervious
and 50% pervious in the calculations per a previous conversation with
City Staff. The impervious roof areas in the calculations are for roofs
on adjacent neighboring properties and the proposed solar panel roof.
The Maintenance Plan has been revised to describe the system and a
section for permeable pavers, green roof, and rain barrels has been
added.
05/15/2019
Page: C2
Author: jackd
File Name: Civil - 211 Cottonwood Lane.pdf
Show what sections of roof are
green roof and show what
sections of roof drain to green
roof. If there are sections that
drain to green roof, a level
spreader is required.
Civil - 211 Cottonwood Lane.pdf (2)
Page: C2
Author: jackd
File Name: Civil - 211 Cottonwood Lane.pdf
Provide green roof detail.
Page: Grade-2 of 6 Temporary Micropile Wall Location
Author: jackd
File Name: Excavation Stabilization - 211 Cottonwood Ln.pdf
Provide a legal agreement
showing the ability to excavate
into the private roadway. Will this
excavation danger road users?
Excavation Stabilization - 211 Cottonwood Ln.pdf (1)
I F
F
G
I
F
F
Show what sections
of roof are green roof
and show what
sections of roof drain
to green roof. If there
are sections that
drain to green roof, a
level spreader is
required.
I F
F
G
I
F
F
H
Provide green roof
detail.
Top of Temporary Slope
at 1.5H:1V
Provide a legal
agreement showing
the ability to excavate
into the private
roadway. Will this
excavation danger
road users?
Green Roof area is shown on sheet C2
with arrows showing flow direction. Solar
panel roof area is shown on sheet C2 with
flow direction. No roof sections drain onto
the green roof so no level spreader is needed.
Green Roof detail is provided on sheet C5.
See letter from Smuggler Home Owners Association.
05/15/2019