HomeMy WebLinkAboutFile Documents.725 Cemetery Ln.0045-2019-BRES (14) Duplex Residences
PARCEL NUMBERS 273512291001 & 273512291002
721, 723, 725, & 727 CEMETERY LANE
ASPEN (PITKIN COUNTY), COLORADO
DRAINAGE REPORT
Reviewed by Engineering
Report Date / History: 03/16/2020 3:24:58 PM
September 27, 2019 / Initial Permit Review "It should be known that this review shall not
January 14, 2020 / Permit Resubmittal relieve the applicant of their responsibility to
comply with the requirements of the City of
Aspen The review and approval by the City is
offered only to assist the applicants
understanding of the applicable Engineering
requirements_"The issuance of a permit based
on construction documents and other data shall
not prevent the City of Aspen from requiring the
correction of errors in the construction
documents and other data
Owner: Developer:
725 Cemetery Duplexes, LLC 725 Cemetery Duplexes, LLC
Attn: Tiffany Phipps Attn: Tiffany Phipps
623 East Hopkins Avenue 623 East Hopkins Avenue
Aspen, Colorado 81611 Aspen, Colorado 81611
Phone: 970-920-1280 Phone: 970-920-1280
Email: Tiffany@AspenStarwood.com Email: Tiffany@AspenStarwood.com
Prepared by:
Yarnell Consulting&Civil Design
P.O. Box 3901 229 Midland Avenue
Eagle, Colorado 81631 Basalt,Colorado
Phone: (970) 323-7008
Engineer-of-Record: Justin Yarnell, PE (CO), President
Email: Justin@TheYarnells.com
YARNELL CONSULTING & CIVIL DESIGN
TABLE OF CONTENTS
Table of Contents
Appendices ii
Engineer's Certification 1
1. General Location and Description 2
1.1. Location 2
1.2. Description of Property 2
1.3. Description of Project 2
1.4. Previous Drainage Studies 3
1.5. Adjacent Drainage Issues 3
1.6. Major Drainageway Planning Studies 3
1.7. Site Constraints 3
1.8. Irrigation Facilities 4
1.9. Drainage Easements /Tracts 4
2. Drainage Basins and Sub-Basins 5
2.1. Major Basin Description 5
2.2. Existing Sub-Basin Description 5
2.3. Proposed Sub-Basin Description 5
3. Low Impact Site Design 8
4. Hydrologic Criteria 9
4.1. Storm Recurrence Intervals 9
4.2. Design Rainfall 9
4.3. Runoff Calculation Method 9
4.4. Detention Discharge and Storage Calculation Method 9
4.5. Other Criteria 9
4.6. Sub-Basin Data 10
4.7. Existing (Pre-Redeveloped) Runoff 10
4.8. Proposed (Post-Redeveloped) Runoff 10
4.9. Water Quality Capture Volume and Runoff 10
4.1. Hydrographs 11
Duplex Residences Page i
YARNELL CONSULTING & CIVIL DESIGN
5. Hydraulic Criteria 12
5.1. Design Point for Closed Systems 12
5.2. Flow Capacity of Drainage Facilities 12
5.3. Culvert Design 12
5.4. Storm System Design 12
5.5. Gutter Design 12
5.6. Inlet Design 12
5.7. Open Channel Design 12
5.8. Check/Channel Drop Design 13
5.9. Downstream /Outfall System Capacity 13
6. Proposed Drainage Facility Design 14
6.1. Water Quality Best Management Practices Design 14
6.2. Detention and Outlet Design 14
6.3. Drainage Easements /Tracts 15
6.4. Off-Site Drainage Facilities 15
6.5. Maintenance 15
7. Conclusions 17
8. References 18
APPENDICES
Maps A
Hydrologic Calculations B
Hydraulic Calculations C
Referenced Documentation D
Duplex Residences Page ii
YARNELL CONSULTING & CIVIL DESIGN
ENGINEER'S CERTIFICATION
I hereby affirm that this report and the accompanying plans for the redevelopment of 721,
723, 725, and 727 Cemetery Lane was prepared by me (or under my direct supervision) for
the owners thereof in accordance with the provisions of the City of Aspen Urban Runoff
Management Plan and approved variances and exceptions listed thereto. I understand that
it is the policy of the City of Aspen that the City of Aspen does not and will not assume
liability for drainage facilities designed by others.
.pQp'00 L l oFy��
c3 �OHN y ti•1s,
SIGNATURE: \ 47241
41 /14/40 '
Justin J.Yarnell 0
CO PE #47241 ''1I``•�S/0NAL tNSI"'
Duplex Residences Page 1
YARNELL CONSULTING & CIVIL DESIGN
1. GENERAL LOCATION AND DESCRIPTION
1.1. Location
The proposed project is located at 721, 723, 725, and 727 Cemetery Lane -more
specifically Lots 1 and 2, Hutton Lot Split,City of Aspen.
1.2. Description of Property
The existing property encompasses a footprint of approximately 39,704 square feet(0.912
acres). It is bounded to the east by Cemetery Lane, and all other sides by single-family
homes. Presently, there is a single-family residence on the property,with associated
asphalt driveway,porch,decks, shed,landscaping, and utilities.Topographically, the site
drains toward the northeast at moderate slopes of less than approximately five (5) percent.
There does not appear to be any storm drainage infrastructure on or immediately adjacent
to the property-not even curb and gutter or a defined swale along Cemetery Lane.
According to Figure 3.1 of the City of Aspen Urban Runoff Management Plan (URMP),the
on-site soils are described as Type C.
1.3. Description of Project
It is proposed to raze the existing residence with its associated asphalt driveway and
parking pad, decks, sheds, foundation, and utility services on the subject property.While
numerous large, mature trees are slated to remain, redevelopment of the site will require
the removal of several other trees which are identified on the Existing Conditions&Demo
Plan sheet C2. In addition to two (2) new duplex buildings totaling four (4) residential
units, the redevelopment will include concrete driveways,paver patios and parking areas,
utilities,and extensive landscaping.The ground cover will be primarily pervious-
consisting of lawn area and planters.
There is no curb and gutter or defined swale along Cemetery Lane. There exists,however, a
colored concrete recreation path within the public right-of-way-west of Cemetery Lane
itself.According to the"Curb & Gutter Locations and Curb & Gutter Deferred Zones" map in
Appendix A of the City of Aspen Engineering Design Standards, this property is not
proposed to be equipped with curb and gutter. The colored concrete recreation path is
Duplex Residences Page 2
YARNELL CONSULTING & CIVIL DESIGN
slated to be removed and replaced in order to improve the grading condition and construct
new utilities beneath it.
1.4. Previous Drainage Studies
The project site is located within the Maroon Creek Basin as defined by Figure 1.2 "City of
Aspen Drainage Basins"within the URMP. In accordance with Section 1.5 of the URMP, the
project has been designed to provide the water quality capture volume and detention for
the 100-year storm event.
There are no other known previous drainage studies applicable to this project site.
1.5. Adjacent Drainage Issues
There are no known drainage issues adjacent to the subject property.
1.6. Major Drainageway Planning Studies
This project site is not within or immediately adjacent to any major drainageways;
therefore, is not subject to any major drainageway planning studies.
1.7. Site Constraints
The project is constrained by a series of elements. First,by a lack of storm drainage
infrastructure on or immediately adjacent to the site such that all runoff is conveyed
overland. Second,the architectural design of the buildings mandated finished floor
elevations just inches above the Cemetery Lane right-of-way.Third, the site plan resulted in
the need to flatten the site which limits the opportunity to convey drainage overland and
necessitating a private, on-site,below-grade storm drainage system. Combined with the
need to keep many of the existing trees on the site, there was insufficient space on the
property to construct a water quality and detention basin that would conform with the
URMP and permit daylighting of the proposed,private storm system. As such,we have
coordinated extensively with the City of Aspen Engineering Department to permit below-
grade chambers to serve both water quality and detention requirements.
Duplex Residences Page 3
YARNELL CONSULTING & CIVIL DESIGN
1.8. Irrigation Facilities
The Holden Marolt Ditch runs approximately parallel with the western property limit. It
lies within an existing easement of varying width. The irrigation ditch is outside the limits
of disturbance for the project; therefore, is not anticipated to impact or be impacted by this
project.
1.9. Drainage Easements / Tracts
Based on the Improvement Survey Plat for the subject property,prepared by Pinnacle
Design, there are no existing drainage easements or tracts on the project site.
Duplex Residences Page 4
YARNELL CONSULTING & CIVIL DESIGN
2. DRAINAGE BASINS AND SUB-BASINS
2.1. Major Basin Description
The project site is located within the Maroon Creek Basin as defined by Figure 1.2 "City of
Aspen Drainage Basins"within the URMP. Based upon a review of aerial photogrammetry,
drainage from the site is conveyed in a northerly direction along Cemetery Lane into
Maroon Creek,and ultimately into the Roaring Fork River. The majority of this basin
appears to consist of single-family residential development.
2.2. Existing Sub-Basin Description
Based upon site reconnaissance by YCCD, no drainage is tributary to the site from the north
or east since the topography trends northeasterly, nor from the west since the irrigation
ditch intercepts off-site flow.A negligible quantity of lawn area from the adjacent property
to the south does appear to drain onto Lot 2.Although a detailed analysis of the existing
condition was not deemed necessary, a cursory review of an aerial photo indicates the sub-
basin is less than 50% impervious. It includes lawn area,trees, roof, and pavement.
According to Figure 3.1 of the URMP, the on-site soils are described as Type C.
2.3. Proposed Sub-Basin Description
As defined on Drainage Plan (Proposed) Sheet D1 within the civil engineering drawing set,
this site has been divided into six (6) proposed sub-basins for purposes of sizing the on-site
storm drainage system, swales, and below-grade stormwater detention system to
accommodate the estimated 100-year volume.
Approximately 0.05 acres in area and 50% impervious, sub-basin PR1 consists of a narrow
strip of softscape,the westerly portion of the existing, shared,asphalt driveway for 729 and
731 Cemetery Lane -a duplex located west of the subject parcel.While the entirety of the
shared asphalt driveway on the subject parcel is graded to drain northerly and off the site,
we are proposing to remove and reconstruct that portion which will be utilized to access
the new residences at 725 and 727 Cemetery Lane. This is against the desires of the city
forester since the trees lining the driveway will be negatively impacted by the regrading.
However, our compromise is to leave the westerly section of driveway undisturbed but
Duplex Residences Page 5
YARNELL CONSULTING & CIVIL DESIGN
account for the detention volume, nonetheless. Runoff generated within this sub-basin is
conveyed overland along historic drainage paths in a northeasterly direction toward
Design Point A along Cemetery Lane.
Approximately 0.17 acres in area and 67%impervious, sub-basin PR2 consists of the
driveway, auto court,front yard,and some roof area on Lot 1. Runoff generated within this
sub-basin is conveyed overland via swales and pans to a proposed,private drainage system
at Design Point B where it is then piped to the proposed below-grade detention system.
Approximately 0.20 acres in area and 52% impervious, sub-basin PR3 consists of the
driveway, auto court,interior courtyard, front yard, and some roof area on Lot 2. Runoff
generated within this sub-basin is conveyed overland via swales and pans to a proposed,
private drainage system at Design Point D where it is then piped to the proposed below-
grade detention system on adjacent Lot 1.
Approximately 0.47 acres in area and 35% impervious, sub-basin PR4 consists of the rear
yards,shared side yards, and a majority of the roof area on Lots 1 and 2. Runoff generated
within this sub-basin is conveyed overland via swales to a proposed, private drainage
system where it is then piped to the proposed below-grade detention system at Design
Point E.
Approximately 0.02 acres in area and 2% impervious, sub-basin PR5 consists of the lawn
area between the westerly property limits and the Holden Marolt ditch. Runoff generated
within this sub-basin is conveyed overland in a sheet-flow condition before being
intercepted by said ditch and conveyed northerly toward Design Point F.While included
within the detention volume calculations,runoff generated in this sub-basin cannot be
captured before reaching the ditch.
Approximately 0.14 acres in area and 71%impervious, sub-basin OS1 consists of
approximately the westerly one-half of the Cemetery Lane right-of-way. Runoff generated
within this sub-basin is conveyed overland toward Design Point A in a roadside ditch
proposed as part of this project.Since this is public right-of-way,it is not tributary to the
site.Alternatively, it is being evaluated to confirm it can be conveyed in the proposed 4-foot
concrete pans without spreading into the travel lanes.
Duplex Residences Page 6
YARNELL CONSULTING & CIVIL DESIGN
Refer to the Rational Method Drainage Calculations in Appendix B for further information
on the drainage sub-basins.
Duplex Residences Page 7
YARNELL CONSULTING & CIVIL DESIGN
3. LOW IMPACT SITE DESIGN
As defined within the URMP, each Major Project is required to incorporate low impact site
design elements to the maximum extent practical. This project is no exception.
First, the use of overland swales was employed to the maximum extent possible.Although
not considered"storage volume" best management practices, allowing runoff to drain
across vegetation maximizes the ability to filter particulates and remove sediment from
surface runoff. However,as mentioned previously, the proposed site plan limited the
available elevation changes for swales.This mandated some below-grade drainage piping.
Second, the project minimizes connected impervious areas. The only connected impervious
area are the two (2) walkways and one (1) driveway to Cemetery Lane. The existing,
shared driveway along the northerly property limit is being utilized to access Lot 1 to not
have a new connection to Cemetery Lane. Otherwise, drainage is routed over vegetated
surfaces.
Third, the project is taking advantage of several large, mature trees on the site that are
slated to remain as part of the redevelopment.
Fourth, the proposed below-grade detention system incorporates a filter fabric to intercept
pollutants before they are introduced into the groundwater via infiltration.
To summarize,painstaking efforts have been taken to reduce runoff by routing drainage
over landscape areas, disconnect impervious area, and omit hard infrastructure - even
when considering the numerous constraints associated with redeveloping this parcel.
Duplex Residences Page 8
YARNELL CONSULTING & CIVIL DESIGN
4. HYDROLOGIC CRITERIA
4.1. Storm Recurrence Intervals
In accordance with the URMP, the 100-year storm event has been studied as the major
storm event.Since all proposed infrastructure is sized to capture,convey, and store runoff
from the major event,it was not deemed necessary to study the 10-year (minor) event.
4.2. Design Rainfall
In accordance with Table 2.3 "Two-Hour Incremental Rainfall Depths for Aspen," the
hydrologic calculations utilize a 100-year, 1-hour precipitation depth of 1.23 inches.
4.3. Runoff Calculation Method
In accordance with Section 3.3 of the URMP, the Rational Method was used to estimate peak
flows from this watershed since the area is less than 90 acres.
4.4. Detention Discharge and Storage Calculation Method
Without a public storm system on or adjacent to the subject parcel,and insufficient
elevation available to daylight a pipe,discharge from the below-grade detention system is
wholly reliant on infiltration.As such, the system is limited to the percolation rate of the
on-site soils which have been estimated by the project's geotechnical engineer to be
between two (2) and five (5) minutes per inch.While we believe it is acceptable to size the
below-grade detention system based upon a release rate that takes into account the lowest
percolation rate spread across the footprint of the system,city engineering staff disagree.
As such,we have substantially over-sized the detention system by assuming a release rate
of zero (0). In accordance with Section 5.6 of the URMP, the Modified Federal Aviation
Administration (FAA) Method was used in conjunction with no release to calculate the
required storage volume.
4.5. Other Criteria
There are no other hydrologic calculation methods that have been used within this analysis
that have not been presented in or referenced by the URMP.
Duplex Residences Page 9
YARNELL CONSULTING & CIVIL DESIGN
4.6. Sub-Basin Data
Refer to Appendix B for a tabulation of the area, storm frequency, rainfall intensity, time of
concentration, and runoff coefficients for each sub-basin.
4.7. Existing (Pre-Redeveloped) Runoff
Since the release rate from the proposed pond is not governed by or limited to a "pre-
redeveloped" rate but percolation rates of the soil, it was not deemed necessary to evaluate
or calculate the "pre-redeveloped" runoff rate.
4.8. Proposed (Post-Redeveloped) Runoff
Appendix B contains the hydrologic calculations for the estimated,proposed runoff rates
tributary to the proposed below-grade detention system at Design Points B and E.A
summary is included below as Table 1.
Table 1:Estimated,Proposed Runoff Rates
Sub-Basin Est 100-year Runoff(CFS)
PR1 0.20
PR2 0.84
PR3 0.78
PR4 1.66
PR5 0.06
OS1 0.67
4.9. Water Quality Capture Volume and Runoff
When designing a combined water quality and detention basin, the WQCV is included
within the detention volume. The proposed below-grade detention system has been sized
in the same manner. Therefore, since the detention volume is substantially greater than the
WQCV, the WQCV has been omitted from consideration and not calculated.
Duplex Residences Page 10
YARNELL CONSULTING & CIVIL DESIGN
4.1. Hydrographs
The hydrograph for the proposed detention pond indicates that approximately 2,904 cubic
feet of storage are required based on the parameters of the tributary sub-basins and no
release from the below-grade detention system.
Duplex Residences Page 11
YARNELL CONSULTING & CIVIL DESIGN
5. HYDRAULIC CRITERIA
5.1. Design Point for Closed Systems
There are no closed systems tied to the city's existing collection system.
5.2. Flow Capacity of Drainage Facilities
Proposed swales have been sized to capture and convey the estimated 100-year tributary
flow rate. Further analysis and discussion is included in the subsequent"Open Channel
Design" section.
5.3. Culvert Design
No culverts are proposed as part of this project.
5.4. Storm System Design
The proposed,private, on-site storm system has been evaluated utilizing the Storm Sewers
Extension for AutoCAD Civil3D®.Appendix C contains a map of the proposed system and
tabulation of each pipe segment to indicate the system can convey the estimated 100-year
flow rate tributary to it without the hydraulic grade line being higher than ground level.
5.5. Gutter Design
No gutters are proposed as part of this project.
5.6. Inlet Design
The "Inlet Capture Capacity Tabulation" in Appendix C indicates the capture capacity for
each inlet.All the inlets proposed as part of this project have been sized to capture the
estimated 100-year flow rate tributary to them even when including a 50% clogging factor.
5.7. Open Channel Design
There are some swales proposed to convey drainage on the subject parcel. However, none
have been noted with critical points mandating a flow analysis since the flow rates are low
and the swales are elevationally lower than the surrounding sites. This means drainage
cannot leave the site uncontrolled from a swale. Therefore,open channel flow capacity is
not foreseen to be an issue.
Duplex Residences Page 12
YARNELL CONSULTING & CIVIL DESIGN
5.8. Check / Channel Drop Design
There are no check/ channel drops associated with this project.
5.9. Downstream / Outfall System Capacity
All runoff generated on this site is tributary to a proposed, on-site,below-grade detention
system at the low point of the site. Since the system is being sized to capture the estimated
100-year flow rate tributary to it and infiltrate the entirety of the volume,it is anticipated
that there will be a reduction in runoff leaving the site; thereby improving the downstream
condition.
Duplex Residences Page 13
YARNELL CONSULTING & CIVIL DESIGN
6. PROPOSED DRAINAGE FACILITY DESIGN
6.1. Water Quality Best Management Practices Design
First, the use of overland swales was employed to the maximum extent possible.Although
not considered"storage volume" best management practices, allowing runoff to drain
across vegetation maximizes the ability to filter particulates and remove sediment from
surface runoff. However, as mentioned previously, the proposed site plan limited the
available elevation changes for swales. This mandated some below-grade drainage piping.
Second,the project minimizes connected impervious areas. The only connected impervious
area are the two (2) walkways and one (1) driveway to Cemetery Lane. The existing,
shared driveway along the northerly property limit is being utilized to access Lot 1 to not
have a new connection to Cemetery Lane. Otherwise,drainage is routed over vegetated
surfaces.
Third,the project is taking advantage of several large,mature trees on the site that are
slated to remain as part of the redevelopment.
Fourth, the proposed below-grade detention system incorporates a filter fabric to intercept
pollutants before they are introduced into the groundwater via infiltration.
To summarize, painstaking efforts have been taken to reduce runoff by routing drainage
over landscape areas, disconnect impervious area,and omit hard infrastructure - even
when considering the numerous constraints associated with redeveloping this parcel.
6.2. Detention and Outlet Design
Without a public storm system on or adjacent to the subject parcel,and insufficient
elevation available to daylight a pipe,discharge from the proposed, on-site,below-grade
detention system is proposed to be facilitated entirely by infiltration into the on-site soils.
As such, there is no outlet structure proposed as part of the project.Alternatively, the
release rate is governed by the percolation rate of the on-site soils (estimated by the
project's geotechnical engineer to be between two [2] and five [5] minutes per inch) and
the approximately 808-square foot footprint of the 100-year detention volume.While we
believe it is acceptable to size the below-grade detention system based upon a release rate
Duplex Residences Page 14
YARNELL CONSULTING & CIVIL DESIGN
that takes into account the lowest percolation rate spread across the footprint of the
system, city engineering staff disagree.As such,we have substantially over-sized the
detention system by assuming a release rate of zero (0). In accordance with Section 5.6 of
the URMP, the Modified Federal Aviation Administration (FAA) Method was used in
conjunction with no release to calculate the required storage volume. This translates to a
required detention volume of approximately 2,904 cubic feet. Calculations for the detention
storage volume can be found in Appendix C.
6.3. Drainage Easements / Tracts
There are no existing or proposed drainage easements or tracts associated with this
project.
6.4. Off-Site Drainage Facilities
All runoff generated on this site is tributary to a proposed, on-site,below-grade detention
system at the low point of the site. Since the pond is being sized to capture the estimated
100-year flow rate tributary to it and infiltrate the entirety of the volume,it is anticipated
that there will be a reduction in runoff leaving the site; thereby improving the downstream
condition.There are no off-site drainage facilities anticipated to be negatively-impacted by
the proposed redevelopment.
6.5. Maintenance
In general, the drainage design is intended to employ vegetated swales and a private storm
drainage system to convey runoff generated on the site to a below-grade detention system
in the northeast quadrant of the site. The system shall be constructed on native,well-
draining gravels. Base course shall be placed on the native material to provide a level
surface to receive the StormTech chambers which shall be connected to the proposed,
private storm sewer system. The chambers shall be backfilled with more gravel,filter fabric
on top of this, and soils placed up to proposed finished grade. The base course shall have a
void ratio not less than 0.4 so it, combined with the chambers, can contain the estimated
100-year detention volume.All discharge from the system shall be accomplished by
infiltration.
Duplex Residences Page 15
YARNELL CONSULTING & CIVIL DESIGN
Maintenance associated with the storm water infrastructure of the project generally
requires that built-up sediment be removed from the vegetated swales, inlets,and piping.
The below-grade detention system shall be vacuumed six(6) months after Lot 1 receives
its certificates of occupancy, and annually thereafter. The goal of this process is to remove
particulates that have collected on top of the filter fabric. For more information, refer to the
manufacturer's literature regarding operations and maintenance in Appendix D.
All maintenance shall be done by the homeowner's associates setup for this project,or its
property manager. The contact information for the owner can be found on the cover of this
report.
Duplex Residences Page 16
YARNELL CONSULTING & CIVIL DESIGN
7. CONCLUSIONS
In conclusion, the drainage design for the proposed redevelopment of 725 Cemetery Lane
into 721, 723, 725,and 727 Cemetery Lane is in full conformance with the City of Aspen
URMP.
Duplex Residences Page 17
YARNELL CONSULTING & CIVIL DESIGN
8. REFERENCES
• "Flood Insurance Rate Map Number 08097C0354E." Federal Emergency
Management Agency. 15 August 2019.
• Hardin, Daniel E."Subsoil Study for Foundation Design, Proposed Duplexes, 725
Cemetery Lane, Lots 1 and 2, Hutton Lot Split,Aspen, Colorado." Kumar&
Associates. 26 June 2019.
Duplex Residences Page 18
YARNELL CONSULTING & CIVIL DESIGN
APPENDIX A - MAPS
Duplex Residences
rn
PROJECT SITE (721 , 723, 725,
AND 727 CEMETERY LANE)
VICINITY MAP
National Flood Hazard Layer FI RMette r.
: FEMA Legend
39°12'10.421l SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
• : ^• `, L► Zon- A 7 .- Ai FLOGT 1?1:Hir 1 Without Base Flood Elevation(BFE)
Q • • o • zone A.V.ass
77.71 FEET
N 1 ' N . •.• 1 [ Zone AE \ With BFE or Depth Zone AE,AO,AH.VE AR
o • i .-.,• , SPECIAL FLOOD
ill
o ` T, w _ � O 777LT 136 FEET. = Zone A: HAZARD AREAS RegulatoryFkwdway
1714/
r . •~ d ' " * . h 0.2%Annual Chance Flood Hazard,Areas
• • , 1 I `q ... •" All of 1%annual chance flood with average
t • • , w"'- II depth less than one foot or with drainage
► • • • r , 9 7780 FEET ') areas of less than one square mile z,, k
• LL -_, ; Zone AE fibre Future Conditions 1%Annual
' 41i !o! IP 77t'f FEE 177ti3 F, EMI Chance Flood Hazard zone x
Vie'‹
EET I " Area with Reduced Flood Risk due to
OTHER AREAS OF Levee.See Notes.zone x
' l'~ FLOOD HAZARD "� Area with Flood Risk due to Leveezone n
3,1)14 k O ta. l
77 _ .�b •' INO SCREEN! Area of Minimal Flood Hazard zone x
aa ..�� ~ • r i 7j FEET r . I V C— I Effective LOMRs
• !�f �" • 77 ?j 4' • • 1" OTHER AREAS Area of Undetermined Flood Hazard Zone o
J . 9SFE�T 1 �F 1' i
�' �' AFT GENERAL -—-- Channel,Culvert,or Storm Sewer
+t` I ;11ilh ‘ L. It • • Z77 F�_ZTone AE 0 ) "� STRUCTURES 11 1 11 1 1 Levee,Dike,orFloodwall
mT s
•..t FeUUDWAY �� 'i
41 . ' T- + I'
1 •' j ® 2°.2 cross Sections with 1%Annual Chance
7802 FEE 7802 FEE 1 rl - 1L Water Surface Elevation
` � Zone A n !I t - - - Coastal Transeet
AREA OF MINIMAL FLOOD HAZARD • I-. rgp7805;8 FEET Base Flood Elevation Line(BFE)
vse a 7P,a'^ •� Limit of Study
3.
. �, ea, F.)r'E 1 s ! �. Jurisdiction Boundary
ONIS T F l ----•— Coastal Transact Baseline
�'~' ib ,— I a.•f OTHER - — Profile Baseline
Approximate site location 08097C0354I ���777 y� FEATURES dro
•� "'r• 7812 FEET14 I Hy graphic Feature
eff.8 5/2019.4,,./. .` .
tW,� Digital Data Available
~ 0 ! ` . If Ili itrt '•/dr. 4.lisi:
No Digital Data Available
MAP PANELS Unmapped
7.8205 EET
! E 17H` ' ' F-- The pin displayed on the map is an approximate
`� - ) point selected by the user and does not represent
sQ ' a Th. " an authoritative property location.
ifif
4 II ,OFF'FT t` This map complies with FEMA's standards for the use of
k,t • •• ti ' �r - " �' - digital flood maps if it is not void as described below.
` , ` 7830 FEET The basemap shown complies with FEMA's basemap
.! )4.
1 M # accuracy standards
I y. ♦ 1�3'3 ... , ` The flood hazard information is derived directly from the
' VD•I t , ,` I N. �_�.��� ,� , authoritative NFHL web services provided by FEMA.This map
y * .� • was exported on 9/26/2019 at 4:11:47 PM and does not
+., 1'S ti: ,�� reflect changes or amendments subsequent to this date and
�� II,.
• f,0'�•AE 1 s • $ time.The NFHL and effective information may change or
itiotiot
become superseded by new data over time.
•
CD
-. t one•AE r •1 + 8 This map image is void if the one or more of the following map
11., rw elements do not appear basemap imagery,flood zone labels,
1 U " N .i9h-I v1��a:;e'a.el, ;e v°'rj ii:i °�o legend,scale bar,map creation date,community identifiers,
39°11'42.54"N FIRM panel number,and FIRM effective date.Map images for
Feet 1:6,000 unmapped and unmodernized areas cannot be used for
0 250 500 1.000 1.500 2,000 regulatory purposes.
YARNELL CONSULTING & CIVIL DESIGN
APPENDIX B - HYDROLOGIC CALCULATIONS
Duplex Residences
P.O. Box 3901 YARNELL CONSULTING & 129 Midland Avenue
Eagle, Colorado 81631 Basalt, Colorado 81621
CIVIL DESIGN, LLC
(970) 323-7008 1/10/2020
Project Name: 725 Cemetery Lane Project No.: 18.033
RATIONAL METHOD DRAINAGE CALCULATIONS
Storm Event: Proposed Jurisdiction: City of Aspen
STORM EVENT: 2 5 I 10 25 I 100 PERCENT
Soil Type: C RUNOFF COEFF.: C, Cc C.,n C75 Cum - IMPERVIOUS
Landscape 0.01 0.05 0.15 0.33 0.49 2.0%
Roof 0.83 0.86 0.87 0.88 0.89 100.0%
Asphalt 0.83 0.86 0.87 0.88 0.89 100.0%
Concrete 0.83 0.86 0.87 0.88 0.89 100.0%
Gravel 0.83 0.86 0.87 0.88 0.89 100.0%
SUB- AREA AREA PER SURFACE CHARACTERISTIC (ac) COMPOSITE
COMPOSITE RUNOFF COEFFICIENTS
BASIN (ac) Landscape' Roof I Asphalt I Concrete I Gravel _ IMPERVIOUS
PR1 0.05 0.03 0.02 _ 0.41 0.45 0.50 0.60 0.69 50.4% _
PR2 0.17 0.06 0.02 0.03 0.07 0.56 0.59 0.63 0.70 0.76 67.2%
PR3 0.20 0.10 0.02 0.08 r 0.42 0.46 0.51 0.61 0.70 51.5%
PR4 0.47 0.31 0.13 0.02 0.28 0.32 0.39 0.51 0.63 34.7%
PR5 0.02 0.02 0.01 0.05 0.15 0.33 0.49 2.0%
0S1 0.14 0.04 0.06 0.04 0.59 0.62 0.66 0.72 0.78 71.4%
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
TOTAL 0.91 I 0.51 I 0.17 I 0.05 I 0.18 I 0.00 I 0.37 I 0.40 I 0.46 I 0.57 I 0.67 I 44.9%
P.O. Box 3901 YARNELL CONSULTING & 129 Midland Avenue
Eagle, Colorado 81631 Basalt, Colorado 81621
CIVIL DESIGN, LLC
(970) 323-7008 1/10/2020
Project Name: 725 Cemetery Lane Project No.: 18.033
RATIONAL METHOD DRAINAGE CALCULATIONS
Storm Event: Proposed STANDARD FORM SF-2 (TIME OF CONCENTRATION SUMMARY)
SUB-BASIN INITIAL/OVERLAND TRAVEL TIME t, CHECK FINAL
DATA TIME (ti) (tt) (URBANIZED BASINS) tc
DESIGN AREA . LENGTH SLOPE ti . LENGTH SLOPE VEL. tt COMP. TOT. LENGTH tc=(L/i8o)+io REMARKS
BASIN POINT CS ac ft ft/ft min ft ft/ft CV fps Min to ft min min
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)
PR1 A 0.45 0.05 26 0.0200 4.8 195 0.0256 15 2.40 1.4 6.1 221.0 11.2 6.1
PR2 B 0.59 0.17 41 0.0610 3.3 70 0.1771 20 8.42 0.1 3.4 111.0 10.6 5.0
PR3 D 0.46 0.20 43 0.0163 6.5 178 0.0438 20 4.19 0.7 7.2 221.0 11.2 7.2
PR4 E 0.32 0.47 47 0.0319 6.6 280 0.0514 0.00 0.0 6.6 327.0 11.8 6.6
PR5 F 0.05 0.02 0.0 0.00 0.0 0.0 0.0 10.0 5.0
0S1 A 0.62 0.14 28 0.0200 3.6 185 0.0189 15 2.06 1.5 5.1 213.0 11.2 5.1
*All calculations are per City of Aspen URMP, Chapter 3 TOC
1/10/2020 1:56 PM
D:\Dropbox\Project Files\18.033-725 Cemetery Lane,Aspen\Engineering\Drainage\2020.01.14 Permit Resubmittal\Rational Method-Aspen
P.O. Box 3901 YARNELL CONSULTING & 129 Midland Avenue
Eagle, Colorado 81631 Basalt, Colorado 81621
CIVIL DESIGN, LLC
(970) 323-7008 1/10/2020
Project Name: 725 Cemetery Lane Project No.: 18.033
RATIONAL METHOD DRAINAGE CALCULATIONS
Storm Event: Proposed STANDARD FORM SF-3 (STORM DRAINAGE SYSTEM DESIGN)
Return Period: 100-YEAR
Rainfall Depth: 1.23
DIRECT RUNOFF TOTAL RUNOFF
BASIN DESIGN AREA RUNOFF t CxA I t S CxA I REMARKS
POINT Q ( ) Q
(AC) COEFF (MIN) (AC) (IN/HR) (CFS) (MIN) (AC) (IN/HR) (CFS)
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
PR1 A 0.05 0.69 6.1 0.03 5.86 0.20
PR2 B 0.17 0.76 5.0 0.13 6.33 0.84
PR3 D 0.20 0.70 7.2 0.14 5.48 0.78
PR4 E 0.47 0.63 6.6 0.29 5.69 1.66 7.2 0.43 5.48 2.37 PR3 +PR4
PR5 F 0.02 0.49 5.0 0.01 6.33 0.06
OS1 A 0.14 0.78 5.1 0.11 6.26 0.67
100-YEAR
*All calculations are per City of Aspen URMP, Chapter 3 1/10/2020 1:56 PM
D:\Dropbox\Project Files\18.033-725 Cemetery Lane,Aspen\Engineering\Drainage\2020.01.14 Permit Resubmittal\Rational Method-Aspen
YARNELL CONSULTING & CIVIL DESIGN
APPENDIX C - HYDRAULIC CALCULATIONS
Duplex Residences
Hydraflow Storm Sewers Extension for Autodesk® Civil 3D® Plan
16
15
14
Outfall
8
Outfall
2 1
4
3
g18
7
4
10
17
5
11
12
13
6
Project File: New.stm Number of lines: 18 Date: 1/10/2020
Storm Sewers v2020.00
MyReport Page
Line Line Line Line Capac Flow Gnd/Rim HGL Gnd/Rim HGL Vel
No. Size Length Slope Full Rate El Dn Dn El Up Up Ave
(in) (ft) (%) (cfs) (cfs) (ft) (ft) (ft) (ft) (ftls)
1 10 2 000 14.99 9.19 2.47 7875.90 7875.70 7883.55 7875.72 4.53
2 10 19 642 1.50 2.90 2.47 7883.55 7876.04 7884.85 7876.25 4.53
3 10 10 729 35.70 14.17 2.47 7884.85 7876.57 7883.18 7879.88 j 4.80
4 8 120.658 1.24 1.45 1.20 7883.18 7880.96 7885.77 7882.51 4.39
5 6 46.585 1.40 0.72 0.40 7885.77 7882.51 7887.71 7883.06 j 2 64
6 6 25.903 1.00 0.61 0.40 7887.71 7883.14 7887.12 7883.42 3.15
7 6 41.892 1.00 0.61 0.40 7885.77 7882.51 7886.00 7882.83 j 2 64
8 6 34.146 1.00 0.61 0.40 7886.00 7882.91 7885.95 7883.27 3.15
9 8 7.924 1.00 1.31 0 80 7883.18 7879.88 7879.93 7879.73 2 87
10 8 36 418 1.00 1.31 0.70 7879.93 7879.73 7880.29 7880.06 j 3.11
111 8 30 615 1.00 1.31 0.60 7880.29 7880.06 7886.15 7880.33 j 2.92
12 6 35.486 1.01 0.61 0.20 7886.15 7881.22 7885.36 7 881.60 2.57
13 6 23.101 1.00 0.61 0.40 7886.15 7880.45 7885.19 7880.70 3.15
14 8 7.093 62.17 10.32 0 84 7875.54 7875.14 7882.75 7879.84 9.62
15 4 9.130 1.00 0.21 0.10 7882.75 7879.84 7883.32 7 879.95 2.23
16 4 12.715 1.02 0.21 0.10 7883.32 7880.03 7880.54 7 880.18 2 25
17 6 18.895 2 01 0.86 0.10 7880.29 7880.06 7884.19 7880.29 j 1.34
18 6 6.228 2 09 0.88 0.10 7879.93 7879.73 7883.74 7879.68 t 31
•
Project File: New.stm Number of lines: 18 Date: 1/10/2020
NOTES: ""Critical depth
Nyloplast Standard Grate Inlet Capacity Chart Basin outlet Flow Rate
Pipe Size CFS•
This chart is based on equations from the FAA Airport Drainage AC 150/5320- 4" 0.229
5B,1970,Page 35.Certain assumptions have been made and no two 0.662
installations will necessarily perform the same way.Safety factors should
change with site conditions such that a safety factor 1.25 should be used for an B" 1.441
inlet in pavement,and a safety factor of 2.0 should be used in turf areas. 10" 2.612
12" 4.152
15" 7.126
18" 12.163
24" 25.821
30" 52.173
.Maximum flow capacity before drain basin begins to backfill.
Calculation based on an average pipe slope of 1%.
Nyloplast Standard Grates 8",10",12",15",18",24"and 30"
9.00
8 30"Grate
7.00
6.00cn 24"Grate
5.00 .
0- 4.00
c� 18"Grate
3.00 15'Grate
2.00 12'Grate
1.00 = 10"Grate
0.00 — — 8-Grate
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10
Head,Feet
THIS PRINT DISCLOSES SUBJECT MATTER IN WHICH DRAWN BY AWA MATERIAL 3130 VERONA AVE
NYLOPLAST HAS PROPRIETARY RIGHTS.THE RECEIPT BUFORD,GA 30518
OR POSSESSION OF THIS PRINT DOES NOT CONFER, DATE o7MARao PHN p7o)93z-zaa3
TRANSFER,OR LICENSE THE USE OF THE DESIGN OR Nylo last FAX(770)932-2490
TECHNICAL INFORMATION SHOWN HEREIN APPD BY CJA •PROJECT NOJNAME www.nyloplastais.com
REPRODUCTION OF THIS PRINT OR ANY INFORMATION TITLE
CONTAINED HEREIN,OR MANUFACTURE OF ANY DATE o7MARao GRATE I COVER g 30"STANDARD INLET CAPACITY
ARTICLE HERE FROM,FOR THE DISCLOSURE TO OTHERS
IS FORBIDDEN,EXCEPT BY SPECIFIC WRITTEN - •
PERMISSION FROM NYLOPLAST. DWG SIZE A SCALE 1:2 SHEET 1 OF 1 DWG NO. 7001.110-001 REV B
P.O. Box 3901 YARNELL CONSULTING 229 Midland Avenue
Eagle,Colorado 81631 & CIVIL DESIGN, LLC Basalt,Colorado 81621
(970) 323-7008 I 1/13/2020
Project Name: 725 Cemetery Lane Project No.: 18.033
INLET CAPTURE CAPACITY TABULATION
Inlet No. Est Tributary Flow Available Head Max.Grate Capacity 1 Design Grate Capacity2
(CFS) (feet) (CFS) (CFS)
Al 0.2 0.4 3.1 1.6
A3 0.5 0.8 1.9 1.0
A4 0.1 1.0 0.5 0.3
A5 0.1 0.9 0.5 0.3
A7 0.4 0.8 0.9 0.5
A8 0.2 1.0 0.5 0.3
A 1 1 0.4 1.1 0.8 0.4
A 13 0.4 0.2 1.0 0.5
B1 0.8 0.3 1.7 0.9
Notes:
1.Capacity determined by the chart from Nyloplast.
2.Assumed 50% reduction in maximum capacity due to clogging.
1 rock Dr c r . Ca Aci+v Cal culocl'i'pr\
E+. ` 1 rt bu-F-ary Flow Ra-i-t- ( O37 ) = 0.10 CF5
lAox. Groc+t- Ca+clmerr{- On -
* From mant-rioc-Fur
L.en&-k of Drain. = 10 LF
Torio.l cox+clew erc = 19$/ I x 10 LF = I9c6.6 oo.
min (LF)
mfr.
= 3.31 _ t
sec
= O.4'1 CF5 > 01 CFS f
Ever 50/ c105✓✓✓✓ 1, 4he. c1 tt.in 5kovlcc 5+ II I/4ecce.{J f
O. �.,} ;
ZZ CF5 , cads +1.0 es-kimAT6d 0.1 CF5ff
-F•ri OAry +0 ►-k
Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc_ Friday, Jan 10 2020
4 ' Concrete Pan
Triangular Highlighted
Side Slopes (z:1) = 12.00, 12.00 Depth (ft) = 0.17
Total Depth (ft) = 0.17 0 (cfs) = 0.670
Area (sqft) = 0.35
Invert Elev (ft) = 7882.60 Velocity (ft/s) = 1 .93
Slope (%) = 0.70 Wetted Perim (ft) = 4.09
N-Value = 0.012 Crit Depth, Yc (ft) = 0.17
Top Width (ft) = 4.08
Calculations EGL (ft) = 0.23
Compute by: Known Q
Known Q (cfs) = 0.67 This calculation indicates the estimated
100-year runoff along Cemetery Lane can be
contained within the proposed 4' concrete pans
without spreading into the travel lane.
Elev (ft) Depth (ft)
Section
7883.00 0.40
v
7882.75 = - • 0.15
7882.50 -0.10
7882.25 - - • -0.35
7882.00 - - -0.60
0 .5 1 1.5 2 2.5 3 3.5 4 4-5 5 5.5
Reach (ft)
P.O. Box 3901 YARNELL CONSULTING 229 Midland Avenue
Eagle, Colorado 81631 & CIVIL DESIGN, LLC Basalt, Colorado 81621
(970) 323-7008 I 9/26/2019
Project Name: 725 Cemetery Lane Project No.: 18.033
DETENTION VOLUME CALCULATION: MODIFIED FAA
Storm Return Period (yr): 100
Area(ac): 0.91 *Calculations are in
Time of Conc.(min.): 6.68 accordance with Section 5.6 of
1-Hour Rainfall Depth (in): 1.23 the City of Aspen Urban
Release Rate (CFS): 0.00 Runoff Management Plan.
Runoff Coefficient: 0.67
Duration Rainfall Intensity Inflow Volume Outflow Storage Volume
(min) (in/hr) (ft3) (ft3) (ft3)
180 0.44 2,904 0 2,904
183 0.43 2,904 0 2,904
186 0.42 2,904 0 2,904
189 0.42 2,904 0 2,904
192 0.41 2,904 0 2,904
195 0.40 2,904 0 2,904
198 0.40 2,904 0 2,904
201 0.39 2,904 0 2,904
MAXIMUM STORAGE VOLUME--> 2,904
2,905
2,905
2,904
2,904
ai
00
0 2,904
2,904
2,904
180 183 186 189 192 195 198 201
Duration(min)
mill,
SI G.
DE N
TOOL 2.
User Inputs Results
Chamber Model: MC-3500 System Volume and Bed Size
Outlet Control Structure: No
Project Name: 725 Cemetery Lane Installed Storage Volume: 2908.19 cubic ft.
Engineer: N/A Storage Volume Per Chamber: 109.90 cubic ft.
Project Location: Colorado Number Of Chambers Required: 14
Measurement Type: Imperial Number Of End Caps Required: 4
Required Storage Volume: 2904 cubic ft. Chamber Rows: 2
Stone Porosity: 30% Maximum Length: 59.85 ft.
Stone Foundation Depth: 20 in. Maximum Width: 15.33 ft.
Stone Above Chambers: 13 in. Approx. Bed Size Required: 917.67 square ft.
Average Cover Over Chambers: 48 in.
System Components
Design Constraint Dimensions: (20 ft.x 60 ft.)
Amount Of Stone Required: 161.73 cubic yards
Volume Of Excavation (Not Including 220.92 cubic yards
Fill):
Br4BECMENT STONE SHALL BE ACLEAN.CRUSHED AN DANGULAR GRANULAR WELL-GRADED SOIVAGGREGAB'EM DNTURES,<35%
STON E WIT H AN AAS HT 0 M43 DESIGNATION BETWEEN 83 AND 84 FINES,C CM PACT IN 12"(300 mm)MAX LIFTS TO 9816 PROCTOR
CHAMBERS SHALL MEET ASTM F2418"STANDARD DENSITY.SEE THE TABLE OF ACCEPTABLE FILL MATERIALS.
SPECIFICATION FOR A OLYPROPLBA E(PA)CORRUGATED CHAMBERS SHALL BE DESIGNED IN ACCORDANCE WITH AVM F2787
WALL STORAWAir ER COLLECTION CHAMBERS", "STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC
CORRUGATED WALL STORAWATER COLLECTION CHAMBERS'.
ADS GEOSYNTHETICS 601T NONWOVEN
OEOT B(TLE ALLAROUND CLEAN,CRUSHED, PAY9AENT LAYER(DESIGNED
ANGULAR BMBEDAEN7 STONE 1� BY SITE DESIGN ENGINEER)
.\lam ��` ,�,,. \� \ �\ �">� �'"�� ` \ '"��`,� \` ��1•^L ¢�`A `C�. >t 8'
PERIMETER STONE I } g4# \e Fes . ;I'tei,4s n .._-U •r'nl,, 0i�3Vn *1-. - ,� 1m) C2 Am)
a3':- c.'� �. � � (450 mm)MIN' MAX
E%CAVAT ION WALL 7' il•�i�lr rf/ h{ r(.11�li
(CAN BE SLOPED •! 1 r ��' 111 Il �I 11 III\,.. f 111�`I�
OR�•ERTI CAL) •
1�1111.1 .�, i ^ III •,/ 1' �`I{ �,)II \i / �II� � !'' \ / III' `1!I \ "Dim)
II-L i �f/ll..l I 1=11= ,''',lil�►1.111.11 '' �11.11 III
1II=1II' VW1=11=11
11=11=II 1.11=11=11=11' =11=11=11'=11=11=11=11=11=11=11=11=11=11=11=11=11=11=11= =11=11=1I=1 1=11=11=11=11=11=11=11=1 —I —I DEPTH OF STONE TO BE DETERMINED
11=IL-1=11 =111.11 - -II-11'=II-11=II-II-II=II-11=11=II-•U-II-II-II-II-II=1 'll-II=11=11 II-11=II-II-11=11-II=11 II L
8"(150 mm)MN =11=11=11=II=11-' 11=11-d1=11=11=1_I=11=11=11=1n.R;TI=1111=11=11=11=I1 J=11=11=11. =1_I=11=11=11=11=11=11=1 BY SITE DESIGN ENGIN4EER 9-(230 mm)MN
1=11=11=II-11=11=0=11=11=7,4 11= — — -MC-3600 — 6. 77"(1950 mm) I2"(300 mm)TYP
END CAP (150 mm)MIN -
SIT EDESIGN ENGINEER IS RESPONSIBLE FOR ENSURING
THE REQUIRED BEARING CAPACITY OF SOILS
'MNMI►A COVER TO BOTTOM OF FLBC IBLE PAVEMENT,FOR UNPAVED INSTALLATIONS WHERE RUTTING FROM\EH IC LES MAY OCCUR,INCREASE COVER TO 24-
c)e� ior\ Sys+ . Drain I imt.
14ro4i or\ rod-c.= 5 r„i n/i r►c 1�
5y5+ h�+oh+ = (-15)+ I.6(i2) = CoLi.2 inches
DrAir` Time.' rA-F� X hci�
= 5 r"= x 19.2 Indio = 321 resin
inch.
= 5.9 hoots 4 72 hors ✓.
YARNELL CONSULTING & CIVIL DESIGN
APPENDIX D - REFERENCED DOCUMENTATION
Duplex Residences
I4ILefr�8 As�atea,[lt�.°
A Geotedmi�and MaterialsEngineers 5020 County Road 154
and Environmental Scientists Glenwood Springs,CO 81601
phone:(970)945-7988
fax:(970)945-8454
email:kaglenwood@kumarusa.com
An Employee Owned Company www.kumarusa.com
Office Locations: Denver(HQ),Parker,Colorado Springs,Fort Collins,Glenwood Springs,and Summit County,Colorado
atiotops
www.kumanmLwm
1989-2o19
SUBSOIL STUDY
FOR FOUNDATION DESIGN
PROPOSED DUPLEXES
725 CEMETERY LANE
LOTS 1 AND 2, HUTTON LOT SPLIT
ASPEN, COLORADO
PROJECT NO. 19-7-347
JUNE 26, 2019
PREPARED FOR:
APSEN STARWOOD, LLC
ATTN: TIFFANY PHIPPS
623 EAST HOPKINS AVENUE
ASPEN, COLORADO 81611
tiffany(aaspenstarwood.com
TABLE OF CONTENTS
PURPOSE AND SCOPE OF STUDY - 1 -
PROPOSED CONSTRUCTION - 1 -
SITE CONDITIONS - 1 -
FIELD EXPLORATION - 2 -
SUBSURFACE CONDITIONS - 2 -
SLOPE STABILIZATION - 2 -
DESIGN RECOMMENDATIONS - 3 -
FOUNDATIONS - 3 -
FOUNDATION AND RETAINING WALLS -4 -
FLOORSLABS - 5 -
UNDERDRAIN SYSTEM - 5 -
SURFACE DRAINAGE - 6 -
DRYWELL - 6 -
LIMITATIONS - 6 -
FIGURE 1 - LOCATION OF EXPLORATORY BORINGS
FIGURE 2 - LOGS OF EXPLORATORY BORINGS
FIGURE 3 - LEGEND AND NOTES
FIGURE 4 AND 5 - GRADATION TEST RESULTS
TABLE 1- SUMMARY OF LABORATORY TEST RESULTS
TABLE 2-PERCOLATION TEST RESULTS
Kumar&Associates,Inc. = Project No.19-7-347
PURPOSE AND SCOPE OF STUDY
This report presents the results of a subsoil study for two proposed duplexes to be located in the
area of the existing residence which will be razed. The project site is shown on Figure 1. The
purpose of the study was to develop recommendations for the foundation design. The study was
conducted in accordance with our proposal for geotechnical engineering services to Aspen
Starwood, LLC dated May 30, 2019.
A field exploration program consisting of exploratory borings was conducted to obtain
information on the subsurface conditions. Samples of the subsoils obtained during the field
exploration were tested in the laboratory to determine their classification and other engineering
characteristics. The results of the field exploration and laboratory testing were analyzed to
develop recommendations for foundation types, depths and allowable pressures for the proposed
building foundation. This report summarizes the data obtained during this study and presents our
conclusions, design recommendations and other geotechnical engineering considerations based
on the proposed construction and the subsurface conditions encountered.
PROPOSED CONSTRUCTION
The proposed duplexes will be two-story wood frame structures over a full basement level.
Basement floors will be slab-on-grade. Grading for the structure is assumed to be relatively
minor with cut depths between about 3 to 12 feet. We assume relatively light foundation
loadings, typical of the proposed type of construction.
If building loadings, location or grading plans change significantly from those described above,
we should be notified to re-evaluate the recommendations contained in this report.
SITE CONDITIONS
The site is currently developed with a two-story wood frame house. The site slopes gently to
moderately down to the east. There appears to have been minor cut and fill for the existing
development. Vegetation consists of landscaped lawn, shrubs and trees. The adjoining parcels
to the north, west and south are developed with condominiums. Cemetery Lane is east of the
property.
Kumar&Associates,Inc. Project No.19-7-347
- 2 -
FIELD EXPLORATION
The field exploration for the project was conducted on June 7, 2019. Four exploratory borings
were drilled at the locations shown on Figure 1 to evaluate the subsurface conditions. The
borings were advanced with 4 inch diameter continuous flight augers powered by a truck-
mounted CME-45B drill rig. The borings were logged by a representative of Kumar&
Associates, Inc.
Samples of the subsoils were taken with a 13/8-inch I.D. spoon sampler. The sampler was driven
into the subsoils at various depths with blows from a 140 pound hammer falling 30 inches. This
test is similar to the standard penetration test described by ASTM Method D-1586. The
penetration resistance values are an indication of the relative density of the subsoils. Depths at
which the samples were taken and the penetration resistance values are shown on the Logs of
Exploratory Borings, Figure 2. The samples were returned to our laboratory for review by the
project engineer and testing.
SUBSURFACE CONDITIONS
Graphic logs of the subsurface conditions encountered at the site are shown on Figure 2. The
subsoils consist of up to about 31/2 feet of organic silty gravelly sand fill overlying relatively
dense, silty sandy gravel with cobbles. Drilling in the dense granular soils with auger equipment
was difficult due to the cobbles and possible boulders and drilling refusal was encountered in the
deposit.
Laboratory testing performed on samples obtained from the borings included natural moisture
content and gradation analyses. Results of gradation analyses performed on small diameter drive
samples (minus 1%-inch fraction)of the coarse granular subsoils are shown on Figures 4 and 5.
The laboratory testing is summarized in Table 1.
No free water was encountered in the borings at the time of drilling and the subsoils were
slightly moist to moist.
SLOPE STABLIZATION
The City of Aspen requires an engineered excavation slope stabilization plan if proposed
foundations are within 15 feet of neighboring structures or public travel ways. The plan is not
Kumar&Associates,Inc. Project No.19-7-347
- 3 -
required if excavations are less than 5 feet below the existing grade or further than 15 feet from
travel ways and less than 15 feet deep. Slope bracing through use of a variety of systems such as
grouting, micro piles and soil nails should be feasible at the site. A shoring contractor should
provide design drawings to support the proposed excavation slopes where needed. Other City
requirements may also be applicable.
DESIGN RECOMMENDATIONS
FOUNDATIONS
Considering the subsurface conditions encountered in the exploratory borings and the nature of
the proposed construction, we recommend the buildings be founded with spread footings bearing
on the natural granular soils.
The design and construction criteria presented below should be observed for a spread footing
foundation system.
1) Footings placed on the undisturbed natural granular soils should be designed for
an allowable bearing pressure of 4,000 psf. Based on experience, we expect
settlement of footings designed and constructed as discussed in this section will
be less than about 1 inch.
2) The footings should have a minimum width of 16 inches for continuous walls and
2 feet for isolated pads.
3) Exterior footings and footings beneath unheated areas should be provided with
adequate soil cover above their bearing elevation for frost protection. Placement
of foundations at least 42 inches below exterior grade is typically used in this
area.
4) Continuous foundation walls should be reinforced top and bottom to span local
anomalies such as by assuming an unsupported length of at least 10 feet.
Foundation walls acting as retaining structures should also be designed to resist
lateral earth pressures as discussed in the "Foundation and Retaining Walls"
section of this report.
5) All existing fill, topsoil and any loose or disturbed soils should be removed and
the footing bearing level extended down to the relatively dense natural granular
soils. The exposed soils in footing area should then be moistened and compacted.
Kumar&Associates,Inc. Project No.19-7-347
- 4 -
6) A representative of the geotechnical engineer should observe all footing
excavations prior to concrete placement to evaluate bearing conditions.
FOUNDATION AND RETAINING WALLS
Foundation walls and retaining structures which are laterally supported and can be expected to
undergo only a slight amount of deflection should be designed for a lateral earth pressure
computed on the basis of an equivalent fluid unit weight of at least 45 pcf for backfill consisting
of the on-site granular soils. Cantilevered retaining structures which are separate from the
duplexes and can be expected to deflect sufficiently to mobilize the full active earth pressure
condition should be designed for a lateral earth pressure computed on the basis of an equivalent
fluid unit weight of at least 40 pcf for backfill consisting of the on-site granular soils.
All foundation and retaining structures should be designed for appropriate hydrostatic and
surcharge pressures such as adjacent footings, traffic, construction materials and equipment. The
pressures recommended above assume drained conditions behind the walls and a horizontal
backfill surface. The buildup of water behind a wall or an upward sloping backfill surface will
increase the lateral pressure imposed on a foundation wall or retaining structure. An underdrain
should be provided to prevent hydrostatic pressure buildup behind walls.
Backfill should be placed in uniform lifts and compacted to at least 90% of the maximum
standard Proctor density at a moisture content near optimum. Backfill in pavement and walkway
areas should be compacted to at least 95%of the maximum standard Proctor density. Care
should be taken not to overcompact the backfill or use large equipment near the wall, since this
could cause excessive lateral pressure on the wall. Some settlement of deep foundation wall
backfill should be expected, even if the material is placed correctly, and could result in distress to
facilities constructed on the backfill. Backfill should not contain organics, debris or rock larger
than about 6 inches.
The lateral resistance of foundation or retaining wall footings will be a combination of the
sliding resistance of the footing on the foundation materials and passive earth pressure against
the side of the footing. Resistance to sliding at the bottoms of the footings can be calculated
based on a coefficient of friction of 0.50. Passive pressure of compacted backfill against the
sides of the footings can be calculated using an equivalent fluid unit weight of 375 pcf. The
Kumar&Associates,Inc. Project No.19-7-347
- 5 -
coefficient of friction and passive pressure values recommended above assume ultimate soil
strength. Suitable factors of safety should be included in the design to limit the strain which will
occur at the ultimate strength,particularly in the case of passive resistance. Fill placed against
the sides of the footings to resist lateral loads should be a granular material, compacted to at least
95%of the maximum standard Proctor density at a moisture content near optimum.
FLOOR SLABS
The natural on-site gravel soils, exclusive of organic sandy fill soils and topsoil, are suitable to
support lightly loaded slab-on-grade construction. To reduce the effects of some differential
movement, floor slabs should be separated from all bearing walls and columns with expansion
joints which allow unrestrained vertical movement. Floor slab control joints should be used to
reduce damage due to shrinkage cracking. The requirements for joint spacing and slab
reinforcement should be established by the designer based on experience and the intended slab
use. A minimum 4 inch layer of free-draining gravel should be placed beneath basement level
slabs to facilitate drainage. This material should consist of minus 2-inch aggregate with at least
50%retained on the No. 4 sieve and less than 2%passing the No. 200 sieve.
All fill materials for support of floor slabs should be compacted to at least 95% of maximum
standard Proctor density at a moisture content near optimum. Required fill can consist of the on-
site granular soils or a suitable imported gravel devoid of vegetation, topsoil and oversized rock.
UNDERDRAIN SYSTEM
Although free water was not encountered during our exploration, it has been our experience in
the area that local perched groundwater can develop during times of heavy precipitation or
seasonal runoff. Frozen ground during spring runoff can create a perched condition. We
recommend below-grade construction, such as retaining walls, crawlspace and basement areas,
be protected from wetting and hydrostatic pressure buildup by an underdrain system.
The drains should consist of drainpipe placed in the bottom of the wall backfill surrounded above
the invert level with free-draining granular material. The drain should be placed at each level of
excavation and at least 1 foot below lowest adjacent finish grade and sloped at a minimum 1%to
a suitable gravity outlet, drywell, or sump and pump. Free-draining granular material used in the
underdrain system should contain less than 2%passing the No. 200 sieve, less than 50%passing
Kumar&Associates,Inc. Project No.19-7-347
- 6 -
the No. 4 sieve and have a maximum size of 2 inches. The drain gravel backfill should be at
least 1%2 feet deep.
SURFACE DRAINAGE
The following drainage precautions should be observed during construction and maintained at all
times after the duplexes have been completed:
1) Inundation of the foundation excavations and underslab areas should be avoided
during construction.
2) Exterior backfill should be adjusted to near optimum moisture and compacted to
at least 95% of the maximum standard Proctor density in pavement and slab areas
and to at least 90% of the maximum standard Proctor density in landscape areas.
3) The ground surface surrounding the exterior of the building should be sloped to
drain away from the foundation in all directions. We recommend a minimum
slope of 12 inches in the first 10 feet in unpaved areas and a minimum slope of 3
inches in the first 10 feet in paved areas. Free-draining wall backfill should be
capped with about 2 feet of the on-site soils to reduce surface water infiltration.
4) Roof downspouts and drains should discharge well beyond the limits of all
backfill.
DRYWELL
Drywells and bio-swales are often used in the Aspen area for site runoff detention and disposal.
The Natural Resources Conservation Service has identified four hydrologic groups (HSG)in the
Aspen area and the site is located in Type C soil having a moderate infiltration rate. The results
of percolation testing performed in Boring 3,presented in Table 1, indicate an infiltration rate
between about 2 to 5 minutes per inch. The bedrock is generally known to be relatively deep in
this area and groundwater level was not encountered to the boring depth of 16 feet. The drywell
should have solid casing down to at least basement level and perforation below that level.
LIMITATIONS
This study has been conducted in accordance with generally accepted geotechnical engineering
principles and practices in this area at this time. We make no warranty either express or implied.
The conclusions and recommendations submitted in this report are based upon the data obtained
Kumar&Associates,Inc.'" Project No.19-7-347
- 7 -
from the exploratory borings drilled at the locations indicated on Figure 1, the proposed type of
construction and our experience in the area. Our services do not include determining the
presence, prevention or possibility of mold or other biological contaminants (MOBC) developing
in the future. If the client is concerned about MOBC, then a professional in this special field of
practice should be consulted. Our findings include interpolation and extrapolation of the
subsurface conditions identified at the exploratory borings and variations in the subsurface
conditions may not become evident until excavation is performed. If conditions encountered
during construction appear different from those described in this report, we should be notified so
that re-evaluation of the recommendations may be made.
This report has been prepared for the exclusive use by our client for design purposes. We are not
responsible for technical interpretations by others of our information. As the project evolves,we
should provide continued consultation and field services during construction to review and
monitor the implementation of our recommendations, and to verify that the recommendations
have been appropriately interpreted. Significant design changes may require additional analysis
or modifications to the recommendations presented herein. We recommend on-site observation
of excavations and foundation bearing strata and testing of structural fill by a representative of
the geotechnical engineer.
Respectfully Submitted,
Kumar& Associates, Inc.
';
AlA
Daniel E. Hardin, . -.;0 24443 2
�. ` /r •.,�� ,
DEH/kac '► o,
cc: Thunderbowl =.irl�i � ett Greene garrett@thunderbowlarchitects.com
Thunderbowl Arcs `=r yan Doremus roan(cithunderbowlarchitects.com
Kumar&Associates,Inc. Project No.19-7-347
1.
Nte l} TN0.S/0-ROAR NO W
7
"""v,t*1 RWA,1 CONO°'\P 261 /‘..
, - -E Pea PtA\6O IM'` I` �� 1 �
L \ \
\ ( 16°6 E -A�,REO OM 01 4
RSE �/so.w 219•\ y�`'� __ !004 -- g e1,
ASPEN Cp\'F GOU , ,I..p°��` ._ �-,,�;�s4,s v'" .�--`� A 1,1a �`t\'\\ \
\nOF Inc _ _.- - 20 �,060 o.A_�-".�.r q
LS/yyRS_-__ ,.,• .=, =•— ` fly-- BORING 2 c�
,�.��p 5nE CAf - l,� JL.., J.- 11rn
5!^" PLP� ,030s ___ �, \PA�O0 ____®e„-->�"`- 50.52' LOT 1 • \ID g- 1 Pwn.O T/� �R,s- - 700 tol'._ — �„_� I GROSS AREA = 22,023t SQUARE FEET \� 1}
re----- - J�/y" • , is
Jb� rn
O � \\
{ �'�` • "kits. ,.+'- u+c'w...K..caxl".` '1 1- 4
N , 4. BORING 1 P ATPROM �y
v' 1.. .\ SEPTIC LID 0) ` i _. e1
Y\ +� S-IEKI RESOENnAI FOOD PRWED KWSE �, •••-� ••} :i
- \ HOIDEN MAROLT DITCH EASEMENTrn
.� Y(PER RECEPTION/624310) i •3
;q \ jj7 g7.
-.1., \-..1 v\,
ty IRONWOODS CONDOMINIUMS cI 4. \V - � 1 , i �,u""V }>liiS�j '+
1 (PER FIAT BOOK 26 PAGE 17) \ k�
Z _ "v
-. @ ay e. \ '
Q, `"l 1 i ,. �� \\ sio ei^n. w•v.w^ g ?'1 \+
Z 11 \;o\\ LOT 2 11\
P 1\ \ ` •\ \� \\ • GROSS AREA= 17,681± SQUARE FEET `
o A •
� �� vvv BORING 3 RING 4 \ v
P %P. \ -- 1 '"`-f• 0..1¢' \ HOLDEN MAROLT DITCH EASEMENT
/ O O 1 '1
\` ; � '. \ftyO!6[CEPnON p26319) S
\ S `\\
\\ Tod -- /c.t rLa 0
,17-87
,1 1 t1 76'28/COS' pr.AE.,P'
1 �� :' \ S (-6,401AA1'LVP'1
5-
/ 0y PR 10.y' /
\ _ •1R
/
__ __.icecap r Ga-f COURSE \ /
ASPEN //
r /
/ -�
PN0.0/0-nuori PLASTIC CAP LS/S06N
C\SY O<
/
/
vle
en
C.
F
P611.1
11
25 0 25 50
X APPROXIMATE SCALE—FEET
g,.
Iy
gii ' 19-7-347 Kumar & Associates LOCATION OF EXPLORATORY BORINGS Fig. 1
BORING 1 BORING 2 BORING 3 BORING 4
EL. 107' EL. 103' EL. 107' EL. 100'
M (2)N„ 0
12/12 11 WC=3. -
WC=5.0 WC3.0
+4=56
4 -200=12 17/12 \ 11/12 -200=14
-
5 50/2 *;:11
30/4, 9/0 31, 25/2 0 1 50/4 5 ^
- WC=5.8
- -200=19 WC=3.9 -
0 _ +4=51 _
w -200=15 w
w- -w
L., w
= 10 10 =
1- 50/4 70/12 i-
w w
0 0
15 15
30/3
- 20 20
m
HI
, E
F'E
r[
19-7-347 Kumar & Associates LOGS OF EXPLORATORY BORINGS Fig. 2
g
U
LEGEND
(1) SCREENED ROCK, THICKNESS IN INCHES SHOWN IN PARENTHESES TO LEFT OF THE LOG.
FILL: SILTY GRAVELLY SAND, ORGANICS, MEDIUM DENSE, SLIGHTLY MOIST, DARK BROWN.
b:
GRAVEL (GM); SANDY, SILTY WITH COBBLES, DENSE, SLIGHTLY MOIST, BROWN.
o -
I
MDRIVE SAMPLE, 1 3/8—INCH I.D. SPLIT SPOON STANDARD PENETRATION TEST.
I
12/12 E UDS A 12 BLOW 1
FALLINGDRIV 30SAMPLE INCHESBLOW WERECO NT.REQUIRED IN INDICATES TO DRIVE THE SAMPLERSOF A 12 INCHES.40—POUND HAMMER
t PRACTICAL AUGER REFUSAL.
NOTES
1. THE EXPLORATORY BORINGS WERE DRILLED ON JUNE 7, 2019 WITH A 4—INCH—DIAMETER
CONTINUOUS—FLIGHT POWER AUGER.
2. THE LOCATIONS OF THE EXPLORATORY BORINGS WERE MEASURED APPROXIMATELY BY PACING
FROM FEATURES SHOWN ON THE SITE PLAN PROVIDED.
• THE ELEVATIONS OF THE EXPLORATORY BORINGS WERE MEASURED BY HAND LEVEL AND REFER
TO THE GROUND SURFACE AT BORING 4 AS ELEVATION 100.0 FEET.
4. THE EXPLORATORY BORING LOCATIONS AND ELEVATIONS SHOULD BE CONSIDERED ACCURATE
ONLY TO THE DEGREE IMPLIED BY THE METHOD USED.
5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY BORING LOGS REPRESENT THE
APPROXIMATE BOUNDARIES BETWEEN MATERIAL TYPES AND THE TRANSITIONS MAY BE GRADUAL.
6. GROUNDWATER WAS NOT ENCOUNTERED IN THE BORINGS AT THE TIME OF DRILLING.
7. LABORATORY TEST RESULTS:
WC = WATER CONTENT (%) (ASTM D2216);
+4 = PERCENTAGE RETAINED ON NO. 4 SIEVE (ASTM D6913);
—200= PERCENTAGE PASSING NO. 200 SIEVE (ASTM D1140).
s2
10
mt
if
1 9—7-347 Kumar & Associates LEGEND AND NOTES Fig. 3
.ti
HYDROMETER ANALYSIS SIEVE ANALYSIS
TIME READINGS U.S. STANDARD SERIES I CLEAR SQUARE OPENINGS
24 HRS 7 NR5 I00 43 MR1 13 MIN 60MIN 19MIN 4149N 114IN 61200 /100 /50#40 /30 416 /1Q/0_—_j4__ /8_ 3/4. 1 1 2' 4' d'6' 6'0
1 1 1
3o - - 1 1_ - - — /0
SO - I - I- —---` 20
T
- - - 1 - --1=
70 - - - - _ --- 1-- ._ 1- _ _ 30
-- - -- 1 -
I
I +.
t
40 i
i _ 1 so W
so 1 1 70
1 1
Ito i
0 _ 1 1 11 I I-_ __ 1-J-1_J.1.-1-I1. 1--_1 1 1-1.1 IL-_ - _.-_ I 1 J-I1111-- 1- 1_'I 1 mil 111 100
.001 .002 .005 .009 .019 .037 .075 .150 .300 I .600 1.18 2.36 4.75 9.5 19 38.1 76.2 1271 200
425 2.0 152
DIAMETER OF PARTICLES IN MILLIMETERS _ - J
SAND GRAVEL
CLAY TO SILT •COBBLES
FINE MEDIUM COARSE FINE COARSE
—
GRAVEL 65 X SAND 23 X SILT AND CLAY 12 X
LIQUID LIMIT PLASTICITY INDEX
SAMPLE OF: Silty Sandy Gravel FROM: Boring 1 O 2.5'
HYDROMETER ANALYSIS SIEVE ANALYSIS
TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS
24 MRS 7 HMI
10D. 1UN_13 MIN SOWN 19MIN 4NN1 114IN /200 /100 _0/40 130 III 410 46 84 3/6' 3/4' I 2' j'_,.46' 3'0
1 I II
SO --- N - - - - i - - I- - - —I'-'-. to
70 - - _ - - 1 30
— _ i
I H
I_ _ 5
00 1 o 30 - _I 70
1 1 1
—I i10 - --1 _ - --- - -- - _ - J 90
1-_
0 1 1 1 I I I .I I I 1.11111 --1_ 1 I _1 I Li__ I __1 L_IJ f 11li- - -T- 1 I 11 rill I too
.001 .002 .005 .009 .019 .037 .075 .150 .300 I .600 1.18 12.36 4.75 9.3 /9 38.1 78.2 127 200
I .425 2.0 152
DIAMETER OF PARTICLES IN MILLIMETERS
i SAND GRAVEL
CLAY TO SILT FINE MEDIUM 'COARSE FINE I COARSE COBBLES
A -
Y
F.
GRAVEL 51 X SAND 34 X SILT AND CLAY 15 Y.
i LIQUID LIMIT PLASTICITY INDEX
These test results apply only to the
SAMPLE OF: Silty Sandy Gravel FROM: Boring 3 ® 5' & 10' (Combined) samples which were fasted. The
testing report shall not be reproduced,
except In full, without the written
L. approval of Kumar & Associates. Inc.
rS Sieve analysis testing Is performed In
accordance with ASTM D6913. ASTM D7928.
I= ASTM C136 and/or ASTM D1140.
R£
14 19-7-347 Kumar& Associates GRADATION TEST RESULTS Fig. 4
HYDROMETER ANALYSIS SIEVE ANALYSIS
tIME REAOBIOS U.S. STANDARD SERIES I CLEAR SQUARE 0/CHINOS
24 MS 7 HMI _ _ _ _
100 4,_S MIMIN_1S MIN 80MIN 1OMIN 4MM MIN 1 60 40 30 16 _10r ra _—� 331_ - 4 j�_ r 4'g C
1 { { I
90 I I 1- 10
so - - 1-- 20
70- 1 - - - 1 - 30
50 ` I50 8
40 .
]GO .
-. - -- 1 70
i
20 _ - -- - - - - — - - -- -,80
10 - -- -'- -- - - — _ .- - -- - 1 90
0 A l III 1 — -I I I I I IAII I I 1 1 1 1 1 1 11 I 1 111 1 1 11 11_LLLL. _ 100
.001 .002 .005 .009 .019 .037 .075 .150 .300 I .600 1.18 2.38 4.75 9.5 19 38.1 76.2 127 200
.425 2.0 152
I DIAMETER OF PARTICLES IN MILLIMETERS
SAND GRAVEL
CLAY TO SILT COBBLES
FINE MEDIUM COARSE FINE COARSE
GRAVEL 56 % SAND 30 X SILT AND CLAY 14 X
LIQUID LIMIT PLASTICITY INDEX
SAMPLE OF: Silty Sandy Gravel FROM: Boring 4 0 2.5'
i
r.
C
n
al
I.
T
t
I
u
These test results apply only to the
asamples which were tested. The
co
testing report shall not be reproduced,
except In full, without the written
pn approval of Kumor & Associates, Inc.
1;7 Sieve analysis testing Is performed In
tit accordance with ASTM D6913, ASTM D7928,
1^/ ASTM C136 and/or ASTM D1140.
Ri
ay 19-7-347 Kumar& Associates GRADATION TEST RESULTS Fig. 5
_ ,
K
�
2 S 2 — 2
§ > § § §
2 d S U S S
ta_ C * a >, W
�
k
cip rip
cA G
0- _
LǤ c-
�§
SMq
22m
- -
I-
®w _
W / k�
co § .
w = e
w ■
E
O a
w I .
CO
6
§
2 - -
_I §U)
A LI.L ~
_ �.
Ce
§ / q / rn
§
CO A
g
§ / Cr) Cr)
0
=ce= k
` » 0z
k_ 2 ±
kr,
\_
°2 � \jI- e 9 M 2
® £ _ - » m m
01 E mmo _ _
§i 1
JJ \ = 2 -
§ [ « ) Cr' «
--- ))) <
0LU
U
LL
2, o `
Cl) o — M m
! � � S
'CA Kumar&Associates,
G l and aterials En
gineers
and Environmental Scientists
TABLE 2
PERCOLATION TEST RESULTS
PROJECT NO. 19-7-347
HOLE HOLE DEPTH LENGTH OF WATER WATER DROP IN AVERAGE
NO. 1 (INCHES) INTERVAL DEPTH AT DEPTH AT WATER PERCOLATION
(MIN) START OF END OF LEVEL RATE
INTERVAL INTERVAL (INCHES) (MIN./INCH)
(INCHES) (INCHES)
B-3 137 5 79 68 11 .5
68 48 20 .3
48 31 17 .3
31 28 3 1.7
28 25 3 1.7
25 23 2 2.5
23 22 1 5.0
22 20 2 1 2.5
_ 20 19 1 5.0
19 18 1 I 5.0
Note: Percolation test was performed in Boring 3 which had caved at about 11.5 feet. Percolation test
was conducted on June 7, 2019.
0
z=- StormTech•
„,.. nm•rra�a�na;•Warr th a�'aE,
---____._,__._--J,.__.z_-__________-:.__:-.__—.__-__,-_-__--_._-_.,'-_._- ,\ -\�,�.1.‘),„,0„1\,;,'I,4‘,1
Isolator Row
v O&M Manual
\, ..,,,,11.1,.„,,,,
A.,„1.1,.„,„,,
\ -k\�0.`\f\=\=\'04t�`\'
i
itirlan
�_._ - i-__� •a.:a i ?.'r.. fir_i i� - + - 1
: i 1 Irtil . '"It--=-
,_. ,....
t ( . w,tNair. k - r - -._.1.,„„---...........,1
.a Y;fi � , wtIk�c�� \ .r• r. r4T ramloo P
` v y
a •
1 0
4 • - SC-7• �1;;-` MC-4500 -
THE MOST ADVANCED NAME IN WATER MANAGEMENT SOLUTIONS 11410
TT-Tr T ZC T ATClp® prw.
INTRODUCTION
An important component of any Stormwater Pollution Prevention
Plan is inspection and maintenance. The StormTech Isolator Row is
a technique to inexpensively enhance Total Suspended Solids(TSS)
removal and provide easy access for inspection and maintenance. (((I I!
THE ISOLATOR ROW
The Isolator Row is a row of StormTech chambers, either SC-160LP,
SC-310, SC-310-3, SC-740, DC-780, MC-3500 or MC-4500 models,
that is surrounded with filter fabric and connected to a closely located
manhole for easy access. The fabric-wrapped chambers provide for Looking down the Isolator Row from the
settling and filtration of sediment as storm water rises in the Isolator manholee enopening,
the ,woven geotextile is shown
between the chamber and stone base.
Row and ultimately passes through the filter fabric. The open bottom
chambers and perforated sidewalls (SC-310, SC- 310-3 and SC-740
models) allow storm water to flow both vertically and horizontally out of —i _ _
the chambers. Sediments are captured in the Isolator Row protecting
the storage areas of the adjacent stone and chambers from sediment ; '
accumulation.
Two different fabrics are used for the Isolator Row.A woven geotextile
fabric is placed between the stone and the Isolator Row chambers. - -
The tough geotextile provides a media for storm water filtration and
provides a durable surface for maintenance operations. It is also s
designed to prevent scour of the underlying stone and remain intact ci
�
during high pressure jetting.A non-woven fabric is placed over the `
chambers to provide a filter media for flows passing through the
perforations in the sidewall of the chamber. The non-woven fabric is not
required over the SC-160LP, DC-780, MC-3500 or MC-4500 models as
these chambers do not have perforated side walls. StormTech Isolator Row with
The Isolator Row is typically designed to capture the "first flush" and Overflow Spillway(not to scale)
offers the versatility to be sized on a volume basis or flow rate basis. F ,Na
An upstream manhole not only provides access to the Isolator Row but P-TRE+TT
typically includes a high flow weir such that storm water flowrates or
volumes that exceed the capacity of the Isolator Row overtop the over STORMTECHISOLATOROW
flow weir and discharge through a manifold to the other chambers. --
' *--qM
The Isolator Row may also be part of a treatment train. By treating +—
PS
storm water prior to entry into the chamber system,the service life can M "wn-
be extended and pollutants such as hydrocarbons can be captured. ,VERW R
Pre-treatment best management practices can be as simple as
deep sump catch basins, oil-water separators or can be innovative
storm water treatment devices.The design of the treatment train and
selection of pretreatment devices by the design engineer is often E H ADER
driven by regulatory requirements. Whether pretreatment is used or not,
the Isolator Row is recommended by StormTech as an effective means =
to minimize maintenance requirements and maintenance costs. _ -�.�--
Note: See the StormTech Design Manual for detailed information on 111-1.
designing inlets for a StormTech system, including the Isolator Row. OPTIONAL
ACCESS STORMTECH CHAMBERS
THE MOST ADVANCED NAME IN WATER MANAGEMENT SOLUTIONS"'
2
-117) ISOLATOR ROW
INSPECTION/MAINTENANCE
INSPECTION
The frequency of inspection and maintenance varies by location.A
routine inspection schedule needs to be established for each individual
location based upon site specific variables. The type of land use (i.e.
industrial, commercial, residential), anticipated pollutant load, percent
imperviousness, climate, etc. all play a critical role in determining the
actual frequency of inspection and maintenance practices.
At a minimum, StormTech recommends annual inspections. Initially,
the Isolator Row should be inspected every 6 months for the first year
of operation. For subsequent years, the inspection should be adjusted
based upon previous observation of sediment deposition.
The Isolator Row incorporates a combination of standard manhole(s) and strategically located inspection ports
(as needed).The inspection ports allow for easy access to the system from the surface, eliminating the need to
perform a confined space entry for inspection purposes.
If upon visual inspection it is found that sediment has accumulated, a stadia rod should be inserted to
determine the depth of sediment. When the average depth of sediment exceeds 3 inches throughout the length
of the Isolator Row, clean-out should be performed.
MAINTENANCE
The Isolator Row was designed to reduce the cost of periodic maintenance. By"isolating" sediments to just
one row, costs are dramatically reduced by eliminating the need to clean out each row of the entire storage
bed. If inspection indicates the potential need for maintenance, access is provided via a manhole(s) located on
the end(s) of the row for cleanout. If entry into the manhole is required, please follow local and OSHA rules for a
confined space entries.
Maintenance is accomplished with the JetVac process.The JetVac process utilizes a high pressure water
nozzle to propel itself down the Isolator Row while scouring and suspending sediments. As the nozzle is
retrieved, the captured pollutants are flushed back into the manhole for vacuuming. Most sewer and pipe
maintenance companies have vacuum/JetVac combination vehicles. Selection of an appropriate JetVac nozzle
will improve maintenance efficiency. Fixed nozzles designed for culverts or large diameter pipe cleaning are
preferable. Rear facing jets with an effective spread of at least 45" are best. Most JetVac reels have 400 feet
of hose allowing maintenance of an Isolator Row up to 50 chambers long. The JetVac process shall only
be performed on StormTech Isolator Rows that have AASHTO class 1 woven geotextile (as specified by
StormTech) over their angular base stone.
StormTech Isolator Row(not to scale)
Note:Non-woven fabric is only required over the inlet pipe connection into the end cap for SC-160LP,DC-780,MC-3500 and MC-4500 chamber
models and is not required over the entire Isolator Row.
SC-TOO.SC310:COVER ENTIRE ISOLATOR ROW WITH ADS -OPTIONAL NSPECTION PORT
GEOSYNTHETCS 801T NONWOVEN GEOTEXTILE ,,.r, F1,5
T�. • .-R"'Q'•Jlll®w
SC.730.P 12.1 mI MIN WIDE , {
SC310.S'(15 nu MIN WIDE I T �N3
MC4500.MC-3500.DC.783,SC-180LP:COVER PIPE q. V�.( • 1. 570RMTECX CNV.ISER
CONNECTION TO END CAP WITH ADS � MO,*WV. :
GEOSYNTHETICS 031T NON-WOVEN DEOTEXTLE / 11,10
vT
§�,B STORMTECN END CAP
CAT OR SIN $¢. 11111 Tt!R {]Zy$ji 7 IY ;L}Z yyy§�' ^!'�, ■ 11 1 , 1!1 1 11
MANHOLE I,Il 11 0:NITe� ` 'i X Ye` ,\ { i;� lITlll�lll�ll��I
SUMP DEPTH WO BY , 5.'}5,'-a]}•,,t,y,,:�
SITE DESIGN ENGINEER
(24.1000 nun)MIN RECOMMENDED) TWO LAVERS OF ADS GEOSYNTXETICS 319NT WOVEN OEOTEXTLE BETWEEN
FOUNDATION STONE AND CHAMBERS.OCNTINUOUS FABRIC WITHOUT SEAMS
W 187E mm FRl HOPE ACCESS E REQUIRED.MC-4503.MG3500.SC.T/0.DC.TBO My 19.1 RI MR WIDE:MC4800
IS(300 Inn)HOPE ACCESS PIPE REOUIREO:SC310 UT(2.5 m)MIN WIDE:MGO500
8'(200 mm)HOPE ACCESS PIPE REQUIRED SC.180LP S(1.5 ml MN WIDE:D07B0./'(1 S m1 MIN WOE SC3 SC-OR10.SG180LP
IRWA:6
MAW
ISOLATOR ROW STEP BY STEP MAINTENANCE PROCEDURES
STEP 1
Inspect Isolator Row for sediment.
A) Inspection ports(if present)
i. Remove lid from floor box frame
ii. Remove cap from inspection riser
iii. Using a flashlight and stadia rod,measure depth of sediment and record results on maintenance log.
iv. If sediment is at or above 3 inch depth, proceed to Step 2. If not, proceed to Step 3.
B)All Isolator Rows
i. Remove cover from manhole at upstream end of Isolator Row
ii. Using a flashlight, inspect down Isolator Row through outlet pipe
1. Mirrors on poles or cameras may be used to avoid a confined space entry
2. Follow OSHA regulations for confined space entry if entering manhole
iii. If sediment is at or above the lower row of sidewall holes(approximately 3 inches), proceed to Step 2.
If not, proceed to Step 3.
STEP 2
Clean out Isolator Row using the JetVac process.
A)A fixed floor cleaning nozzle with rear facing nozzle spread of 45 inches or more is preferable
B)Apply multiple passes of JetVac until backflush water is clean
C)Vacuum manhole sump as required
STEP 3
Replace all caps, lids and covers, record observations and actions.
STEP 4
Inspect&clean catch basins and manholes upstream of the StormTech system.
1)B 2 1)A)
Timimrt
`ii,IjAlA_ng1I! 6IAIAg
LI______:__.
SAMPLE MAINTENANCE LOG
Stadia Rod Readings Sediment Depth
Date Fixed point to chamber Fixed point to top of (1)_(2) Observations/Actions Inspector
bottom(1) I sediment(2)
3/15/11 6,3 f E hoKe New iKsEaLLatioh, Fixed poihE is CI frame at b3M
grade
9/24/11 6.2 0•1 fE Some gri.E f etE SPA
6/20/13 5.8• 0.5 f E Muck?feel,debris vistble L t manhole and Lln NV
Isolator Row, maLNEetAatce due
7/7/13 6.3 f t 0 System jeEEed o, c& vacuumed TOM
ADS"Terms and Conditions of Sale-are available on the ADS webn,te,own,ads-pipe.com �'�,LormTech°
• 1, -. ---":".-..
I
The ADS logo and the Green Stripe are registered trademarks of Advanced Drainage Systems.Inc. S■
Stormtech•and the Isolator•Row are registered trademarks of StormTech,Inc. `
02017Advanced Drainage Systems,Inc.e11011 09l17 CS pyrnnnn•Iirteaer•IW+ergaay
A diudsaon of MIS
Advanced Drainage Systems,Inc.
4640 Trueman Blvd.,Hilliard,OH 43026
1-800-821-6710 www.ads-pipe.com