HomeMy WebLinkAbout1.07 Engineering Report
Preliminary Engineering Report
MCCLURE RIVER RANCH
16411 OLD HIGHWAY 82
CARBONDALE, CO
September 24, 2024
Prepared by
Jordan A. Kehoe, PE
Roaring Fork Engineering
592 Highway 133
Carbondale, CO 81623
ROARING FORK
ENGINEERING
McClure River Ranch
Preliminary Engineering Report
Table of Contents
1.0 General ................................................................................................................................................... 1
1.1 Existing Conditions .......................................................................................................................... 1
2.0 Proposed Site Plan .................................................................................................................................. 1
3.0 Drainage ................................................................................................................................................. 2
3.1 Basin Descriptions ............................................................................................................................ 2
3.1.1 Existing Drainage Pattern........................................................................................................ 2
3.1.2 Proposed Drainage Pattern ...................................................................................................... 2
3.2 Peak Discharge Calculations ............................................................................................................ 2
3.3 Stormwater Management.................................................................................................................. 3
3.3.1 Street Runoff ........................................................................................................................... 3
3.4 Erosion Control & Water Quality ..................................................................................................... 3
3.5 Floodplain Development .................................................................................................................. 3
4.0 Access ..................................................................................................................................................... 3
4.1 Roadway Classification .................................................................................................................... 3
4.1.1 Emergency Vehicle Access ..................................................................................................... 4
4.1.2 Typical Roadway Sections ...................................................................................................... 4
5.0 Utilities ................................................................................................................................................... 4
5.1 Domestic Water ................................................................................................................................ 4
5.2 Sanitary Sewer .................................................................................................................................. 5
5.3 Electric .............................................................................................................................................. 6
5.4 Gas .................................................................................................................................................... 6
5.5 Communications ............................................................................................................................... 6
Appendix ....................................................................................................................................................... 1
Appendix A ............................................................................................................................................ 2
USDA – NRCS Web Soil Survey ......................................................................................................... 2
Appendix B ............................................................................................................................................. 3
Precipitation Intensity ........................................................................................................................... 3
Appendix C ............................................................................................................................................. 4
FEMA – FIRMette ................................................................................................................................ 4
C.C. Cerise Gilligan Ditch Map ............................................................................................................ 4
Appendix D ............................................................................................................................................ 5
Approved Floodplain Development Permit .......................................................................................... 5
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Preliminary Engineering Report
Appendix E ............................................................................................................................................. 6
Approved FEMA CLOMR ................................................................................................................... 6
Appendix F ............................................................................................................................................. 7
Well Pump Test Results ........................................................................................................................ 7
Appendix G ............................................................................................................................................ 8
Geotech Report ..................................................................................................................................... 8
McClure River Ranch 1
Preliminary Engineering Report
1.0 General
1.1 Existing Conditions
Roaring Fork Engineering (RFE) has prepared this report for a site plan application for 16411 Old
Highway 82, Carbondale, CO 81623 (Parcel ID: 239131123010). The 48.96-acre property is zoned
Planned Unit Development (PUD). There exists a barn and greenhouse structures on the site presently. A
gravel driveway accesses these structures off Chukka Trail, an access road on the neighboring property,
under the same ownership. Access can be seen in the image below. For the purposes of this report, the site
will be defined as the area proposed for development.
Figure 1: Garfield County GIS Vicinity View
(Parcel ID 239131123010 shown in blue)
The topography of the site slopes from the east to the west. The site is generally flat. Steeper slopes exist
along banks of streamed portions of the site, but these steeper areas are mostly outside of the proposed
building areas. The existing land cover consists of trees, scrub oaks, shrubs, and other natural vegetation
and grasses. Runoff from the site discharges to the west and southwest towards the Roaring Fork River.
The site is bordered by Zone District 1 of the PUD to the north and the Roaring Fork River to the south.
The site is within the Federal Emergency Management Agency (FEMA) Zone B and Zone C areas. These
areas can be seen in the Civil Drawings as well as the Appendix of this report.
2.0 Proposed Site Plan
The proposed site improvements include the development of a PUD with twelve individual resident lots, a
water treatment facility, and improvements to the barn and greenhouse area. Associated utilities for each
Site
Location
McClure River Ranch 2
Preliminary Engineering Report
lot as well as road infrastructure to access each of the lots will also be included in the development. All
site disturbance will occur within appropriate envelopes as shown in the proposed site plan.
3.0 Drainage
All site disturbance will occur within appropriate envelopes as shown in the proposed site plan. The
proposed site grading will be designed to not exceed 3:1 per Garfield County code section 7-204. Per
section 7-204 of the Land Use Code, development will not occur where existing slopes are 30% or greater
– unless development cannot avoid such areas.
The stormwater runoff from the site is not anticipated to have any adverse impacts to downstream
properties or resources.
Runoff from offsite contributing drainage areas will be analyzed to determine if any mitigation is needed
for offsite run-on. All infrastructure, including ditches and culverts will be sized to safely convey the 25-
year 24-hour storm event away from proposed development and other structures. A Drainage Report will
be included as part of the building permit submittal.
3.1 Basin Descriptions
3.1.1 Existing Drainage Pattern
The existing site consists of one major drainage basin and flows from the east to the west. Several offsite
irrigation ditches enter and leave the site as well as onsite flood irrigation ditches. The Middle Ditch and
C. C. Cerise Gilligan Ditch run east to west in the central portion of the site. Additional ditch information
can be seen in the Appendix. Lower Ditch enters and exits in the SW corner of the property. No
underground drainage facilities are located within the existing site.
Floodplains exist within the site and can be seen on the FIRM map, found in Appendix C.
3.1.2 Proposed Drainage Pattern
The proposed development consists of two major drainage basins with a portion of runoff being directed
to a proposed onsite retention pond west of the intersection of Riverstone Drive and Mayfly Bend. The
remainder of the runoff will be directed towards the southwest area of the site where it will be conveyed
by means of ditches and sheet flow until it reaches existing wetlands for water quality treatment. These
ditches will be rerouted to work with proposed development but be sized to maintain the existing flow.
3.2 Peak Discharge Calculations
Peak flows were calculated for 10-, 25- and 100-year storm events. Rainfall intensity was calculated using
a Time of Concentration (Td) of 5 minutes, the smallest valid time of concentration value was used. The
1-hour NOAA Rainfall depth (P1), given as 0.773 inches for the 10-year event, 0.952 for the 25-year
event, and 1.20 inches for the 100-year event.
The following equations were used to calculate intensity.
I = 88.8P1/(10+Td )1.052
Runoff coefficients (C), a function of the hydrologic soil group (in this case, a mix of groups B & C) and
the percentage of impervious area within each sub basin were developed. The runoff coefficient was then
multiplied by the rainfall intensity (I) and the acreage of each major basin (A) to determine the peak
McClure River Ranch 3
Preliminary Engineering Report
discharge for the Major Basin. Q allowable was calculated the same way, except the basin was treated as
undeveloped, or 100% pervious. The Peak Discharge (Qp) in cubic feet per second (cfs) is given by the
equation below.
Qp= CIA
Qp= Peak Discharge (cfs)
A= Area (acres)
I= Rainfall intensity (inches per hour)
C= Runoff Coefficient (unitless)
3.3 Stormwater Management
Onsite flows will be infiltrated onsite. Flows from the roads will drain to ditches that will act as bioswales
for water quality and infiltration. Ditches will convey water away from the site and to grassed and native
vegetation fields within the property. All historic flows offsite will be maintained.
3.3.1 Street Runoff
All street runoff will drain from the crowned centerline and either sheet flow towards grassed areas for
water quality treatment or be conveyed by roadside ditches towards grassed areas for water quality
treatment. Other than culverts to convey storm water across roads, no storm piping is required.
3.4 Erosion Control & Water Quality
Erosion control measures will be installed during construction to control runoff and sediment from
leaving the site. Permanent erosion control measures will be installed where necessary for final site
protection. Erosion control devices may include but are not limited to; erosion logs, silt fence, storm drain
protection, check dams, erosion matting, sediment traps and concrete washouts. An Erosion Control Plan
will be provided with the Final Engineering Plans for the McClure River Ranch Zone District 2.
All stormwater will be treated onsite with stormwater infrastructure, grassed areas, and the retention
pond, and no further water treatment will be needed. Individual stormwater treatment will be provided for
each lot, as they will be developed at a later phase.
3.5 Floodplain Development
A Floodplain Development Permit and FEMA CLOMR have been previously approved for the
development at the site. These permits can be seen in the Appendix. To ensure compliance with current
permits, RFE conducted the grading analysis with the actual CAD data as prepared by Drexell, Barrell &
CO for the Floodplain Site Plans dated 12/23/09. This allowed us to confirm that all proposed fill
locations within the 100-year floodplain are consistent with what has been approved by Garfield County
and FEMA. A Floodplain Exhibit can be seen in the Engineering Plans and displays the amount of cut
and fill for the project with respect to existing grades on site.
4.0 Access
4.1 Roadway Classification
The proposed subdivision is accessed from Highway 82 Access Road, paralleling Highway 82 and within
Highway 82 ROW. From Highway 82 Access Road, access is provided through the previously platted
Zone District 1 by means of the existing road, Chukka Trail, and thence turning onto Riverstone Drive
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Preliminary Engineering Report
and Mayfly Bend. Riverstone Drive and Mayfly Bend are all private access roads as part of the PUD
development and are twenty-two feet wide with a two-foot-wide gravel shoulder on both sides. The
termination of Riverstone Drive has a cul-de-sac while Mayfly circulates back onto Chukka Trail.
4.1.1 Emergency Vehicle Access
Emergency vehicle access is provided for all proposed building parcels according to the Carbondale Fire
Department. The project is accessible from the primary access located at the intersection of Highway 82
Access Road and Chukka Trail.
4.1.2 Typical Roadway Sections
All Typical Road Section details can be found in the Engineering Plans.
5.0 Utilities
5.1 Domestic Water
Potable water will be pumped from two wells (Permit Number 84785-F and 89030-F) 1 well located in
Zone District 1 and 1 in Zone District 2 of the Aspen Polo Partners, LLP property. The wells are
permitted to produce 60 gallons per minute (GPM) of water and will be used one at a time to supply the
community with the necessary water. Well test results indicate a sustainable recharge rate, with Well 7
recovering to 100% of static water level (SWL) within 75 minutes, and Well 1 recovering to 100% of
SWL within 6 minutes. At this level of production and recharge, the wells will be able to adequately
support the estimated domestic demands. Well pump test graphic results are included in the Appendix.
Water quality samples have been taken at both wells in accordance with Colorado Department of Public
Health and Environment (CDPHE) regulations.
Water will be piped to a water treatment facility, treated in compliance with all CDPHE regulations, and
then distributed to individual parcels through a 6” ductile iron pipe main line running through the
subdivision. Service lines will be tapped from the water distribution system to bring drinking water to
each individual residence and ADUs as well as the community center, event pavilion, and an existing
greenhouse. Water use at the outdoor event pavilion will be seasonal and will be frost protected.
Water demands for the development were estimated using the Town of Carbondale’s Equivalent
Residential Unit (EQR) schedule and assumed flow per EQR definition of 350 GPM per EQR. The 2021
International Fire Code (IFC) was used to calculate required fire storage and the storage volume was
approved by the Carbondale Rural Fire District. Total system water demand is summarized in Error!
Not a valid bookmark self-reference..0 below along with listed assumptions and calculations.
Five (5) fire hydrants will be located within the subdivision to provide adequate fire suppression water
throughout the subdivision. Fire hydrant locations meet Carbondale Fire District hydrant location spacing
standards. Two (2) 25,000-gallon fire suppression tanks will be located near the water treatment facility,
which will also be used for domestic water storage and disinfection. The total required storage was
determined by calculating required fire storage per the 2021 International Fire Code (IFC), and 24 hours
of average domestic demands. All habitable structures within the community will be equipped with fire
sprinkler systems in accordance with NFPA 13, therefore reducing fire storage requirements to 500 GPM
for 60 minutes.
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Preliminary Engineering Report
Table 1.0 System Water Demand
5.2 Sanitary Sewer
An OWTS system will be designed for the Community Center building and a portion of that tract has
been dedicated for its use. Sizing and design of the OWTS will be provided during the building permit
phase. Each property will possess their own individual OWTS system on their respective lot. All OWTS
systems, be it common for the neighborhood or specific for each property, will adhere to Regulation 43 of
the CDPHE and the Garfield County OWTS Requirements, or whichever is more stringent.
McClure River Ranch
Daily Water Demand Calculations
Parameter I Value I Unit I Notes
EQR Conversion Factor I 350 I gpd/E QR I
Residences
Residential Size 10,000 SF M aximum ho use size
EQR per Home EQ R = (Size -1500 SF)/100 SF'0.03 EQR + 1 EQR, minus EQR of two hose bi bs and 2,SUI.
square feet of irrigated lawn . Irrigation not included in calculations. Irriga t ion will use
2.85 EQR raw water so urce. Based on Carbondale EQR Req uirements.
Wate r Use Per House 997.5 gpcd
Residential Units 12 eac h
Total Res idential Water Demand 11970 gpd
Additional Dwelling Units (ADUs)
ADU s 12 units One AD U per lot.
EQR per ADU 0.6 EQR One kitchen, up to 1,500 sf. Does not i nclude irrigation.
Water Use per ADU 210 gpu
Total ADU Water Demand 2520 gpd
Community Buildings
Community Bu ild ings 3 eac h One com mu nity center, eve nt pavilion, and greenhouse.
Water Use Per Build ing 80 gpd /b
Water Use Per Bui ld in g 80 gpd/b
Total Community Building Water Demand 240 gpd
Horse • Dri nking Dema nd
Number of Ho rses allowed per County Code I 12 I horses 11 ho rse per lot
Water Use per Horse I 11 I gpd !Ho rses d rink 5 -11 gallons per day typically
Total Horse Drinking Water Demand l 132 I gpd I
Horse -Washing Demand
Number of Ho rse Washings Per Week 1 ho rse wash
Number of Horses 12 gpu
Wate r Use per Horse Wash 25 gpu
Ho rse Wash ing Water Demand 300 gpw
Tota l Horse Was hi ng Water Demand per Day 43 gpd
Total Dally Water Demand 14905 gpd
Tota l Annua l Wa t er Demand 5440273 gpd
Total Annual Water Demand 16.7l AF/yr
WATER TREATMENT SYSTEM DESIGN
Well Flowrate 60 gpm
Average Daily Demand (Not Including Irrigation) 14905 gpd
Maximum Daily Demand Ra t io 2 unitless
Maximum Daily Demand 29810 gpd
1 Day of Do mest ic Storage 14905 ga l
M i nimum Fire Storage Volume 30000 ga l -500 gpm • 60 minut es/hour
Typical Dead Storage 5000 ga l
Recommen ded Minimum Tank Size 49905 gal
WELL PUMP RUNTIME
Well Flowrat e I 60 I gpm I
Average Da lly Demand W ell Pum p Run t ime I 4 .1 I hrs/day I
Maximum Daily Demand Well Pump Runtime I 8.3 I hrs/day I
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Preliminary Engineering Report
5.3 Electric
Holy Cross Energy electric lines will be run throughout the subdivision with transformers located as
necessary per Holy Cross Energy requirements. New electric service lines will be connected to the
transformers to serve individual lots and meet their electric demand requirements. All proposed electric
lines will be buried. The layout of the electric system and corresponding transformers can be seen in the
Engineering Plans.
5.4 Gas
Gas is provided for each lot and details of the trenching can be found within the Engineering Plans.
5.5 Communications
Telephone, internet, TV, and other communications lines may be installed as part of the site
improvements. All proposed communications lines will be buried to appropriate bury depths as required
by service line owners and Garfield County.
McClure River Ranch
Preliminary Engineering Report
Appendix
McClure River Ranch
Preliminary Engineering Report
Appendix A
USDA – NRCS Web Soil Survey
United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Aspen-Gypsum Area,
Colorado, Parts of Eagle,
Garfield, and Pitkin
Counties
Natural
Resources
Conservation
Service
July 22, 2024
USDA
~
NRCS
9
Custom Soil Resource Report
Soil Map
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314940 315030 315120 315210 315300 315390 315480 315570 315660 315750
314940 315030 315120 315210 315300 315390 315480 315570 315660 315750
39° 24' 16'' N
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39° 24' 16'' N
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39° 23' 58'' N
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39° 23' 58'' N
10
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N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 150 300 600 900
Feet
0 50 100 200 300
Meters
Map Scale: 1:3,850 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
13 Atencio-Azeltine complex, 3 to
6 percent slopes
12.5 26.6%
42 Fluvaquents, 0 to 10 percent
slopes
3.9 8.4%
92 Redrob loam, 1 to 6 percent
slopes
30.4 65.0%
120 Water 0.0 0.0%
Totals for Area of Interest 46.8 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
Custom Soil Resource Report
12
pure taxonomic classes but rather to separate the landscape into landforms or
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soil phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
Custom Soil Resource Report
13
Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin
Counties
13—Atencio-Azeltine complex, 3 to 6 percent slopes
Map Unit Setting
National map unit symbol: jq4y
Elevation: 5,900 to 6,500 feet
Mean annual precipitation: 15 to 18 inches
Mean annual air temperature: 44 to 46 degrees F
Frost-free period: 105 to 120 days
Farmland classification: Not prime farmland
Map Unit Composition
Atencio and similar soils:60 percent
Azeltine and similar soils:30 percent
Minor components:10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Atencio
Setting
Landform:Terraces, alluvial fans
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Alluvium derived from sandstone and shale
Typical profile
H1 - 0 to 10 inches: sandy loam
H2 - 10 to 20 inches: sandy clay loam
H3 - 20 to 30 inches: gravelly sandy loam
H4 - 30 to 60 inches: very gravelly sand
Properties and qualities
Slope:3 to 6 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.20 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:10 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: Low (about 4.9 inches)
Interpretive groups
Land capability classification (irrigated): 4s
Land capability classification (nonirrigated): 4s
Hydrologic Soil Group: B
Ecological site: R048AY306UT - Upland Loam (Wyoming Big Sagebrush)
Other vegetative classification: Rolling Loam (null_60)
Hydric soil rating: No
Custom Soil Resource Report
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Description of Azeltine
Setting
Landform:Alluvial fans, terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Alluvium derived from sandstone and/or alluvium derived from
shale
Typical profile
H1 - 0 to 9 inches: gravelly sandy loam
H2 - 9 to 16 inches: gravelly loam
H3 - 16 to 60 inches: extremely gravelly sand
Properties and qualities
Slope:3 to 6 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:10 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: Very low (about 2.4 inches)
Interpretive groups
Land capability classification (irrigated): 4s
Land capability classification (nonirrigated): 4s
Hydrologic Soil Group: B
Ecological site: R048AY306UT - Upland Loam (Wyoming Big Sagebrush)
Other vegetative classification: Rolling Loam (null_60)
Hydric soil rating: No
Minor Components
Other soils
Percent of map unit:10 percent
Hydric soil rating: No
42—Fluvaquents, 0 to 10 percent slopes
Map Unit Setting
National map unit symbol: jq5z
Elevation: 3,500 to 7,200 feet
Mean annual precipitation: 14 to 18 inches
Custom Soil Resource Report
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Mean annual air temperature: 45 to 52 degrees F
Frost-free period: 80 to 150 days
Farmland classification: Not prime farmland
Map Unit Composition
Fluvaquents and similar soils:90 percent
Minor components:10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Fluvaquents
Setting
Landform:Flood plains, valley floors
Down-slope shape:Concave
Across-slope shape:Linear
Parent material:Mixed alluvium
Typical profile
H1 - 0 to 10 inches: variable
H2 - 10 to 24 inches: stratified gravelly sand to clay
H3 - 24 to 60 inches: very gravelly sand
Properties and qualities
Slope:0 to 10 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Somewhat poorly drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table:About 6 to 24 inches
Frequency of flooding:Occasional
Frequency of ponding:None
Calcium carbonate, maximum content:10 percent
Maximum salinity:Nonsaline to moderately saline (0.0 to 8.0 mmhos/cm)
Available water supply, 0 to 60 inches: Low (about 5.7 inches)
Interpretive groups
Land capability classification (irrigated): 6w
Land capability classification (nonirrigated): 6w
Hydrologic Soil Group: B/D
Ecological site: R048AY010UT - Wet Fresh Streambank (Willow)
Other vegetative classification: riverbottom (null_19)
Hydric soil rating: No
Minor Components
Redrob
Percent of map unit:10 percent
Hydric soil rating: No
Custom Soil Resource Report
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92—Redrob loam, 1 to 6 percent slopes
Map Unit Setting
National map unit symbol: jq7r
Elevation: 5,800 to 7,200 feet
Mean annual precipitation: 16 to 18 inches
Mean annual air temperature: 40 to 44 degrees F
Frost-free period: 85 to 105 days
Farmland classification: Not prime farmland
Map Unit Composition
Redrob and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Redrob
Setting
Landform:Flood plains, terraces, valley floors
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium derived from sandstone and shale
Typical profile
H1 - 0 to 14 inches: loam
H2 - 14 to 20 inches: stratified loamy sand to stony loam
H3 - 20 to 60 inches: extremely cobbly loamy sand
Properties and qualities
Slope:1 to 6 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Somewhat poorly drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table:About 18 to 48 inches
Frequency of flooding:Rare
Frequency of ponding:None
Calcium carbonate, maximum content:10 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: Low (about 4.3 inches)
Interpretive groups
Land capability classification (irrigated): 4w
Land capability classification (nonirrigated): 4w
Hydrologic Soil Group: C
Ecological site: R048AY010UT - Wet Fresh Streambank (Willow)
Other vegetative classification: riverbottom (null_19)
Hydric soil rating: No
Custom Soil Resource Report
17
Minor Components
Fluvaquents
Percent of map unit:10 percent
Landform:Flood plains
Hydric soil rating: Yes
Other soils
Percent of map unit:5 percent
Hydric soil rating: No
120—Water
Map Unit Composition
Water:95 percent
Minor components:5 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Minor Components
Aquolls
Percent of map unit:5 percent
Landform:Marshes
Down-slope shape:Linear
Across-slope shape:Linear
Hydric soil rating: Yes
Custom Soil Resource Report
18
McClure River Ranch
Preliminary Engineering Report
Appendix B
Precipitation Intensity
NOAA Atlas 14, Volume 8, Version 2
Location name: Carbondale, Colorado, USA*
Latitude: 39.4043°, Longitude: -107.1442°
Elevation: 6308 ft**
* source: ESRI Maps
** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
Sanja Perica, Deborah Martin, Sandra Pavlovic, Ishani Roy, Michael St. Laurent, Carl Trypaluk, Dale
Unruh, Michael Yekta, Geoffery Bonnin
NOAA, National Weather Service, Silver Spring, Maryland
PF_tabular | PF_graphical | Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Duration Average recurrence interval (years)
1 2 5 10 25 50 100 200 500 1000
5-min 1.31
(1.04‑1.67)
1.92
(1.54‑2.46)
2.89
(2.30‑3.72)
3.66
(2.89‑4.73)
4.64
(3.49‑6.19)
5.36
(3.95‑7.30)
6.05
(4.28‑8.50)
6.70
(4.52‑9.73)
7.49
(4.85‑11.3)
8.04
(5.09‑12.5)
10-min 0.960
(0.768‑1.22)
1.41
(1.13‑1.81)
2.12
(1.69‑2.72)
2.68
(2.12‑3.46)
3.40
(2.56‑4.54)
3.93
(2.89‑5.35)
4.43
(3.13‑6.22)
4.90
(3.31‑7.13)
5.48
(3.55‑8.27)
5.89
(3.73‑9.13)
15-min 0.780
(0.624‑0.996)
1.14
(0.916‑1.47)
1.72
(1.37‑2.21)
2.18
(1.72‑2.81)
2.77
(2.08‑3.69)
3.20
(2.35‑4.35)
3.60
(2.55‑5.06)
3.98
(2.69‑5.80)
4.46
(2.88‑6.72)
4.78
(3.03‑7.42)
30-min 0.522
(0.418‑0.668)
0.742
(0.594‑0.950)
1.08
(0.864‑1.39)
1.35
(1.07‑1.75)
1.70
(1.27‑2.26)
1.94
(1.43‑2.64)
2.17
(1.54‑3.05)
2.39
(1.61‑3.47)
2.65
(1.71‑3.99)
2.83
(1.79‑4.39)
60-min 0.345
(0.276‑0.441)
0.458
(0.366‑0.587)
0.634
(0.506‑0.815)
0.773
(0.612‑0.999)
0.952
(0.716‑1.27)
1.08
(0.795‑1.47)
1.20
(0.850‑1.68)
1.31
(0.888‑1.91)
1.45
(0.940‑2.19)
1.55
(0.979‑2.40)
2-hr 0.214
(0.173‑0.271)
0.272
(0.220‑0.344)
0.363
(0.292‑0.461)
0.434
(0.347‑0.555)
0.527
(0.401‑0.693)
0.594
(0.442‑0.797)
0.657
(0.470‑0.910)
0.717
(0.490‑1.03)
0.789
(0.517‑1.17)
0.840
(0.537‑1.28)
3-hr 0.167
(0.136‑0.210)
0.202
(0.164‑0.254)
0.258
(0.209‑0.326)
0.303
(0.244‑0.384)
0.361
(0.278‑0.473)
0.404
(0.304‑0.540)
0.446
(0.322‑0.615)
0.486
(0.335‑0.694)
0.537
(0.354‑0.793)
0.573
(0.368‑0.869)
6-hr 0.110
(0.091‑0.136)
0.125
(0.103‑0.155)
0.150
(0.123‑0.187)
0.171
(0.139‑0.214)
0.201
(0.158‑0.262)
0.225
(0.172‑0.299)
0.249
(0.183‑0.341)
0.274
(0.192‑0.389)
0.308
(0.206‑0.452)
0.334
(0.217‑0.500)
12-hr 0.069
(0.057‑0.084)
0.078
(0.064‑0.095)
0.093
(0.077‑0.115)
0.107
(0.088‑0.132)
0.127
(0.101‑0.164)
0.143
(0.110‑0.188)
0.159
(0.118‑0.216)
0.177
(0.125‑0.248)
0.201
(0.136‑0.292)
0.220
(0.144‑0.325)
24-hr 0.042
(0.035‑0.050)
0.048
(0.040‑0.058)
0.058
(0.049‑0.071)
0.067
(0.056‑0.082)
0.081
(0.065‑0.103)
0.091
(0.071‑0.119)
0.103
(0.077‑0.138)
0.115
(0.082‑0.159)
0.131
(0.090‑0.188)
0.144
(0.096‑0.210)
2-day 0.025
(0.021‑0.029)
0.028
(0.024‑0.034)
0.034
(0.029‑0.041)
0.040
(0.034‑0.048)
0.048
(0.039‑0.061)
0.055
(0.043‑0.070)
0.062
(0.047‑0.081)
0.069
(0.050‑0.094)
0.079
(0.055‑0.112)
0.087
(0.058‑0.125)
3-day 0.018
(0.015‑0.022)
0.021
(0.018‑0.025)
0.025
(0.022‑0.030)
0.029
(0.025‑0.035)
0.035
(0.029‑0.044)
0.040
(0.032‑0.051)
0.045
(0.034‑0.059)
0.050
(0.036‑0.068)
0.057
(0.040‑0.080)
0.063
(0.042‑0.089)
4-day 0.015
(0.013‑0.017)
0.017
(0.014‑0.020)
0.020
(0.017‑0.024)
0.024
(0.020‑0.028)
0.028
(0.023‑0.035)
0.032
(0.025‑0.040)
0.036
(0.027‑0.046)
0.040
(0.029‑0.053)
0.045
(0.031‑0.063)
0.049
(0.033‑0.070)
7-day 0.010
(0.008‑0.012)
0.011
(0.010‑0.013)
0.013
(0.012‑0.016)
0.015
(0.013‑0.018)
0.018
(0.015‑0.022)
0.020
(0.016‑0.025)
0.022
(0.017‑0.029)
0.025
(0.018‑0.033)
0.028
(0.020‑0.038)
0.030
(0.021‑0.042)
10-day 0.008
(0.007‑0.009)
0.009
(0.008‑0.010)
0.010
(0.009‑0.012)
0.012
(0.010‑0.014)
0.014
(0.011‑0.017)
0.015
(0.012‑0.019)
0.017
(0.013‑0.022)
0.019
(0.014‑0.025)
0.021
(0.015‑0.029)
0.023
(0.015‑0.031)
20-day 0.005
(0.004‑0.006)
0.006
(0.005‑0.007)
0.007
(0.006‑0.008)
0.008
(0.007‑0.009)
0.009
(0.007‑0.011)
0.010
(0.008‑0.012)
0.011
(0.008‑0.013)
0.012
(0.009‑0.015)
0.013
(0.009‑0.017)
0.014
(0.009‑0.019)
30-day 0.004
(0.004‑0.005)
0.005
(0.004‑0.005)
0.005
(0.005‑0.006)
0.006
(0.005‑0.007)
0.007
(0.006‑0.008)
0.008
(0.006‑0.009)
0.008
(0.006‑0.010)
0.009
(0.007‑0.012)
0.010
(0.007‑0.013)
0.011
(0.007‑0.015)
45-day 0.003
(0.003‑0.004)
0.004
(0.003‑0.004)
0.004
(0.004‑0.005)
0.005
(0.004‑0.006)
0.006
(0.005‑0.007)
0.006
(0.005‑0.007)
0.007
(0.005‑0.008)
0.007
(0.005‑0.009)
0.008
(0.006‑0.010)
0.008
(0.006‑0.011)
60-day 0.003
(0.002‑0.003)
0.003
(0.003‑0.004)
0.004
(0.003‑0.004)
0.004
(0.004‑0.005)
0.005
(0.004‑0.006)
0.005
(0.004‑0.006)
0.006
(0.004‑0.007)
0.006
(0.005‑0.008)
0.007
(0.005‑0.009)
0.007
(0.005‑0.010)
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for
a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not
checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical
7/22/24, 10:59 AM Precipitation Frequency Data Server
https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=39.4043&lon=-107.1442&data=intensity&units=english&series=pds 1/4
------
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Maps & aerials
Small scale terrain
7/22/24, 10:59 AM Precipitation Frequency Data Server
https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=39.4043&lon=-107.1442&data=intensity&units=english&series=pds 2/4
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Large scale map
Large scale aerial
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7/22/24, 10:59 AM Precipitation Frequency Data Server
https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=39.4043&lon=-107.1442&data=intensity&units=english&series=pds 3/4
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US Department of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
Questions?: HDSC.Questions@noaa.gov
Disclaimer
+
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100km
60mi
7/22/24, 10:59 AM Precipitation Frequency Data Server
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McClure River Ranch
Preliminary Engineering Report
Appendix C
FEMA – FIRMette
C.C. Cerise Gilligan Ditch Map
C.C. Cerise Gilligan Ditch Exhibit from
Colorado Division of Water Resources
-···-· /
~. -·. CID •62J,
I MILE
6000 7000 FEET
I KILOMETER
STANDARDS
:25 OR WASHINGTON, D. C. 20242
AVAILABLE ON REQUEST
::·.
CS'<S>oo
Ii;\" ... >, . ..,
r 8;
4362
ROAD CLASSIFICATION
Light-duty ...
Unimproved dirt ~========
, State Route
I
I
• ··-•··-·---.. ··-···---•i--,
i CARBONDALE. COLO .
N3922.5-Wl0707.5/7.5
1961
AMS 4562 I NW-SERIES V877
McClure River Ranch
Preliminary Engineering Report
Appendix D
Approved Floodplain Development Permit
1111 ~~•. ~~1r'/~Mli. ~ Ni~, I.Xt.+Jtl+il~tlri/~~"' 11111
Receptiontt: 786310
05/21/2010 11:09:46 AM Jean Alberico
2 of 5 Rec Fee:$0.00 Doc Fee:0.00 GARFIELD COUNTY CO
EXHIBIT A -TCI Lane Ranch PUD Floodplain Permit
1. All representations of the applicant within the application shall . be considered
conditions of approval unless otherwise modified by the Director Determination.
2. Prior to issuance of the Final Plat for TCI Lane Ranch PUD the Applicant shall
provide a copy of the conditional FIRM and floodway map revision approved
through FEMA.
3. No alterations of the floodplain may be made other than the specific
improvements noted in the application and shown on drawings by James
Brzostowicz, P.E., as labeled "General Layout Pedestrian Bridge" and
"Floodplain Site Plan Lots" Sheets 1 and 2 attached hereto as Exhibit B.
4. All new construction or substantial improvements shall be designed (or modified)
and adequately anchored to prevent flotation, collapse or lateral movement of the
structure resulting from hydrodynamic and hydrostatic loads, including the effects
of buoyancy.
5. All new construction or substantial improvements shall be constructed with
materials resistant to flood damage.
6. All new construction or substantial improvements shall be constructed by
methods and practices that minimize flood damage.
7. All new construction or substantial improvements shall be constructed with
electrical, heating, ventilation, plumbing, and air conditioning equipment and
other service facilities that are designed and/or located so as to prevent water
from entering or accumulating within the components during conditions of
flooding.
8. All new and replacement water supply systems shall be designed to minimize or
eliminate infiltration of flood waters into the system.
9. New and replacement sanitary sewage systems shall be designed to minimize or
eliminate infiltration of flood waters into the system and discharge from the
systems into flood waters.
10. On-site waste disposal systems shall be located to avoid impairment to them or
contamination from them during flooding.
11. No disturbance of a regulated wetland shall be allowed.
McClure River Ranch
Preliminary Engineering Report
Appendix E
Approved FEMA CLOMR
McClure River Ranch
Preliminary Engineering Report
Appendix F
Well Pump Test Results
Figure 1
1428-3.0 11/15/2017
Prepared by DNR
10
15
20
25
30
35
40
45
50
55
60
650
10
20
30
40
1 10 100 1000
Fl
o
w
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(
g
p
m
)
De
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t
h
f
r
o
m
T
O
C
(
f
e
e
t
)
Pumping Time (minutes)
Aspen Polo Partners, New Well Pumping Test 11/31/2017
Depth from TOC (feet)
Depth of Water from TOC Static Water Level
Manual Measurements Flow Rate
Static Water Level = 13.80 ft.
Notes:
1) Initial Water Level: 13.80 ft. below Top of Well Casing
2) Final Water Level: 25.25 ft. below Top of Well Casing
3)Well Depth: 41 ft. from Top of Well Casing
4)Pump Intake Depth: 40 ft. from Top of Well Casing
Average Pumping Rate = 60 gpm
Top of Casing
20 Minutes @ 16.6 gpm
1,420 Minutes @ 61 gpm
8&--/0
1&3.*5/0'
I I
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~-
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■■ .RESOURCE = = E N G I N E ER I N G , I NC .
909 Colorado Avenue I Glenwood Spnngs, CO 81601
Voice (970) 945-6777 -'Web. www.rHource◄ng.com
I I I I I I I I
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--
--
--
! ! ! ! I ! ! ! !
•
Figure 2
1428-3.0 11/15/2017
Prepared By DNR
Max drawdown after 7.1 Hours
(426 Minutes) of pumping = 11.45 ft
10
15
20
25
30
35
40
45
50
55
60
650
10
20
30
40
1 10 100 1000
Fl
o
w
R
a
t
e
(
g
p
m
)
Dr
a
w
d
o
w
n
(
f
e
e
t
)
Pumping Time (minutes)
Aspen Polo Partners, New Well Pumping Test 11/31/2017
Drawdown (feet)
Drawdown Flow Rate
Average Pumping Rate = 60 gpm
Static Water Level
20 Minutes @ 16.6 gpm
1,420 Minutes @ 61 gpm
8&--/0
1&3.*5/0'
I I I I I I I I I
I I I ! ! I I I ••·•·•+-
~-
----1 -
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■■ .RESOURCE = = E N G I N E ER I N G, I N C.
909 Colorado Avenue I Glenwood Spnngs, CO 81601
Voice (970) 945-6777 -'Web. www.rHource◄ng.com
I I I
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Figure 3
1428-3.0 11/15/2017
Prepared By DNR
0
1
2
3
4
5
6
7
8
9
10
11
12
2202002000
Re
c
o
v
e
r
y
(
f
e
e
t
)
T/T' (minutes)
Aspen Polo Partners, New Well Pumping Test 11/31/2017
Recovery Analysis (feet)
Residual Drawdown (Feet)
Aquifer recovered100%
Full Recovery @ 75 Minutes
End of Pump Test
Recovery Begins
8&--/0
1&3.*5/0'
. ,.
I
I
~
iiiii RESOURCE 100 E N G I N E ER I N G , I N C "
909 Colorado Avenue I Glenwood Spnngs, CO 8 1601
Voice (970) 945-6777 • \o\leb. www.resource-eng.com
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Well 1 Pump Test Results
1 10
Time Elapsed Since Start of Test (mins)
100 1000 10000
•
McClure River Ranch
Preliminary Engineering Report
Appendix G
Geotech Report
c::;o2;tech
HEPWORTH -PAWLAK GEOTECHNI CAL
H ep,wnh-r311 l.1k (1l'lllL'Lhl11L:.li. lnL .
5020 l.1111nr) R<>.t-1 l 5-f
C,lem 1,1,,J S1•nn~,, l ',,IPra,I,, tilbL11
Plwne: ll70-',1-!'i-71lti~
fac lJ?Q-ll-!'i-8-!5-!
e111,1 d : hp!c(en@ h p_gl"nlc:ch.u,111
PRELIMINARY GEOTECHNICAL STUDY
PROPOSED TCI LANE RANCH SUBDIVISION
HIGHWAY 82 AND EAST OF COUNTY ROAD 100
GARFIELD COUNTY, COLORADO
JOB NO. 106 0920
MARCH 14, 2008
PREPARED FOR:
TCI LANE RANCH, LLC
C/O NOBLE DESIGN STUDIO
ATTN: JON FREDERICKS, ASLA
19351 HIGHWAY 82
CARBONDALE, COLORADO 81623
Parker 101-84 1-7 11 9 • Cnlora dn Spr ings 7 19-6 n-5562 • S ih-errhnrne L)7(L46H -l L)~L)
TABLE OF CONTENTS
PURPOSE AND SCOPE OF STUDY ........................................................................ -1 -
SITE CONDITIONS ................................................................................................... - 1 -
REGIONAL GEOLOGIC SETTING .......................................................................... - 2 -
PROJECT SITE GEOLOGY ...................................................................................... -3 -
RIVER TERRACES AND DEPOSITS ................................................................... - 4 -
EAGLE VALLEY EV APO RITE ............................................................................ - 4 -
GEOLOGIC SITE ASSESSMENT ............................................................................. - 5 -
RIVER FLOODING ............................................................................................... -5 -
SINKHOLES .......................................................................................................... -5 -
EARTHQUAKE CONSIDERATIONS ................................................................... -6 -
RADIATION POTENTIAL ........................................................................................ - 7 -
FIELD EXPLORATION ............................................................................................ - 8 -
SUBSURFACE CONDITIONS .................................................................................. -8 -
PRELIMINARY DESIGN RECOMMENDATIONS .................................................. - 8 -
FOUNDATIONS .................................................................................................... -9-
BELOW GRADE CONSTRUCTION ..................................................................... -9 -
FLOOR SLABS ...................................................................................................... - 9 -
SURF ACE DRAINAGE ....................................................................................... -10 -
PAVEMENT SECTION ....................................................................................... -10 -
LIMITATIONS ........................................................................................................ -10 -
REFERENCES ......................................................................................................... -12 -
FIGURE I -PROJECT SITE LOCATION
FIGURE 2 -GEOLOGICALLY YOUNG FAULTS AND LARGER HISTORIC
EARTHQUAKES
FIGURE 3 -WESTERN COLORADO EV APORITE REGION
FIGURE 4 -PROJECT AREA GEOLOGY MAP
FIGURE 5-LOCATION OF EXPLORATORY PITS
FIGURE 6 -LOGS OF EXPLORATORY PITS
FIGURE 7 -LEGEND AND NOTES
FIGURE 8 -SWELL-CONSOLIDATION TEST RESULTS
FIGURES 9, 10, 11 & 12 -GRADATION TEST RESULTS
TABLE 1-SUMMARY OF LABORATORY TEST RESULTS
PURPOSE AND SCOPE OF STUDY
This report presents the results of a preliminary geotechnical study for the proposed
residential subdivision at TCI Lane Ranch located n01ih of the Roaring Fork River and
east of the Blue Creek Ranch Subdivision, Garfield County, Colorado. The project site is
shown on Figure I. The purpose of the study was to evaluate the geologic and subsurface
conditions and their potential impact on the project. The study was conducted in
accordance with our proposal for geotechnical engineering services to TCI Lane Ranch,
LLC, dated December 20, 2007 . We previously conducted percolation testing for a septic
system design on the property and presented our findings in a repo1i dated October 31 ,
2006, Job No. 106 0920.
A field exploration program consisting of a reconnaissance and exploratory pits was
conducted to obtain information on the site and subsurface conditions. Samples of the
subsoils obtained during the field exploration were tested in the laboratory to detennine
their classification, compressibility or swell and other engineering characteristics. The
results of the field exploration and laboratory testing were analyz ed to develop
recommendations for project planning and preliminary design . This report summarizes
the data obtained during this study and presents our conclusions and reconm1endations
based on the proposed development and subsurface conditions encountered.
SITE CONDITIONS
The TCI Lane Ranch covers about l 00 acres and is located in the Roaring Fork River
valley about three and one-half miles upstream of Carbondale, see Figure 1. The
prope1iy lies to the north of the river and is entirely on the nearly leve l val1ey floor. The
valley floor has an average s lope of about 2 percent down to the west. It is made up of
several river te1Tace levels that are separated by low escarpments. The escarpments are
typically about 6 to 20 feet high and have slopes of about 50 to 70 percent. The terrace
surfaces lie between about 4 to 46 feet above the river. The Fro ntage Road for Highway
82 is located along the northern prope1ty line. Parts of the southern property line are in
Job No. I 06 0920 ~tech
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the Roaring Fork River channel. The Blue Creek Subdivision borders the property on the
west and rural homes and agricultural land are located on the properties to the east. At
the time of this study several houses and ranch buildings were located in the east -central
part of the TCI Lane Ranch. Much of the ranch is irrigated hay fields and pas ture which
are locat ed mostly on the hig her teITace surfaces. Cottonwood trees, other trees and brush
are typical of the vegetation on the lower te1Tace s. Poorly drained wetlands are also
present on the lo wer teITaces .
PROPOSED DEVELOPMENT
The proposed development at the TCI Lane Ranch will be mo stly a residenti al
subdivision as shown on Figure 4. A plant nurser y will be located ill the northwestern
part of the property. The lowest teITaces along the river will not be developed and
undeveloped ground wil l remain a long Highway 82. Eighty-nine residential lot s are
propo sed. Other development facilities will include a network of streets, a community
park and other community facilities .
If development plans change significantly from tho se described, we should be notified to
re-evaluate the recommendations presented in this report.
REGIONAL GEOLOGIC SETTING
The project site is in the Southern Rocky Mountains to the west o f the Rio Grande rift and
to the east of the Co lorado Plateau, see F igure 2. The site is in the western Co lorado
evaporite region and is in the Carbondale co llap se center, see Figure 3. Th e Carbond a le
co llapse center is the western of two regional evaporite collapse centers in western
Co lorado . It is an iJ.Tegular-shaped, no rthwest trending region between the Whit e River
uplift and Piceance basin. It covers about 460 square mile s. As mu ch as 4,000 feet of
regional subs idence is b e lieved to have occuITed during the past 10 million years in the
vi cinity of Carb ondale as a result of dissolution and flow age of evaporite from beneath
the regions (Kirkham and Others, 2002). The evaporite is mostly in the Eagle Valley
Evaporite with some in the Eagle Vall ey Formation. The Eagle Vall ey Evaporite is the
near surface formation rock below the surficial soil deposits at the project site. It crops
Jo b No. I 06 0920 ~tech
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out on t he steep valley sid e to the south of the river, see Figure 4. Much of the evaporite
related subsidence in the Carbondale collapse center appears to have occurred within th e
past 3 million years which also corresponds to hig h incision rates along the Roaring Fork,
Co lorado and Eagle Rivers (Kunk: and Others, 2002). T hi s indicates that long-term
subs idence rates have been ver y slow, between about 0.5 and 1.6 inches per 100 years. It
is uncertain ifregional evaporite sub sidence is still occuning or if it is currently inactive.
If stil l active these regional deformations because of their ver y slow rates should not have
a significant impact on the propose development at the TCI Lane Ranch.
Geologically young fau lt s related to evaporite tectonics are present in the Carbondale
co llapse center but considering the nature of evaporite tecto nics, these fau lt are not
co nsidered capable of generating large earthquakes. The closest geologically you ng
faults that are less than about 15,000 years old and considered capable of generating large
earthquakes are located in the Rio Grande rift to the east of the project site, see Figure 2.
The northern section of the Williams Fork Mountains fault zone Q50 is located about 60
mil es to the n01theast and the southern section of the Saw at ch fault zone Q56b is located
about 60 miles to the southeast. At these distances large earthquakes on these two
geologically yo ung fault zones should not produce strong ground shaking at the project
site that is greater than the ground shaking sho wn o n the U. S. Geological Survey 2002
National Seismic Hazards Maps (Frankel and Others, 200 2).
PROJECT SITE GEOLOGY
The geo lo gy in the project area is sho wn o n Figure 4 . This map is based on our field
observations and is a modification of the regional geo logy m ap by Kirkham and
Widmann (1997). Near surface formation rock is the middle Pennsylvanian-age, Eagle
Valley Evaporite. This reg ional rock for mation was depo sit ed in t he central Co lorado
trough during the Ancestral Rocky Mountain orogeny about 300 million years ago. At
the project sit e the evaporite is cover ed by a series of Roaring Fo rk River t e1Taces and
deposit s that are associated with cycli c periods of deposition and erosion related to g lac ia l
and interglacial climatic fluctuat ions during about the past 35 thousand years.
.J ob No. 106 0920 ~tech
-4 -
RIVER TERRACES AND DEPOSITS
Remnants of seven river terrace levels (Qtl through Qt7) are present at the project site.
The lower four terraces are probably related to post-Pinedale climatic fluctuations during
the past 15 thousand years. Terrace Qtl li es within 4 feet of the river. Terrace Qt2 li es
about 6 feet above the river, terrace Qt3 lies about 12 feet above the river and terrace Qt4
is about 22 feet above the river. The Qtl terraces are small river bank terraces and
channel bar deposits. The Qt2 terraces are old abandoned river channels that lie below
the Qt3 terrace surface. The three higher te1races are probably associated with the late
Pleistocene-age, Pinedale glaciations between abo ut 15 and 35 thousand years ago.
Terrace Qt5 lies about 38 feet above the river, terrace Qt6 lies about 40 feet above the
river and te1race Qt 7 lies about 46 feet above the river.
Our exploratory pits show that the alluvial deposits below terrace levels Qt3 through Qt7
are similar. They consist of a thin, less than 1-foot thick to 3-foot thick, topsoil formed in
soft, silty clay over-bank deposits . The over-bank deposits overHe river alluvium that
consists of rounded gravel-to boulder-size rocks in a relatively clean sand matrix. The
ri ver a llu vium extended to the bottom of the exploratory pits that were excavated to
depths of around 9 feet. Judging from water well records in the Co lorado State
Engineer's data base the river alluvium is probably in the range of 40 to 50 feet deep in
the project area.
EAGLE VALLEY EV APO RITE
The Eagle Valley Evaporite underlies the Roaring Fork River a llu vium in the project area
and as discussed above may extend to depths of 40 to 50 feet below the tenace surfaces.
The Eagle Valley Evaporite is a sequence of evaporite rocks consisting of massive to
laminated gypsum, anhydrite, and halite interbedded with light-colored mudstone, fine-
grained sandstone, thin limesto ne and dolomite beds and black shale (Kirkham and
Widmann, 1997). The evaporite minerals are relatively soluble in circulating ground
water and subsurface solution voids and related surface sinkholes are locally present in
these rocks throughout the western Colorado evaporite region where the evaporite is near
J ob No. l 06 0920 ~tech
-5 -
the surface, see Figure 3. Sinkholes were not observed at the project site during our fie ld
work but the snow cover at that time may have obscured sinkho les if present.
GEOLOGIC SITE ASSESSMENT
Geologic conditions that could present an unusually high risk to the proposed
development were not identified by this stud y but there are geo logic conditions that
should b e considered in the project planning and design. These conditions, their potential
risks and possible mitigations to reduce the risks are discussed below. Geotechnical
engineering design co nsiderations are presented in the Preliminary Design
Recommendations section o f this report.
RIVER FLOODING
The low lying terraces a long the Roaring Fork River may be subject to periodic flooding
during hi gh river flow s. The hydro logic study conducted for the project storm wat er
management plan design should evaluate the potential for river flooding and p ossible
methods to protect project facilities from an appropriate des ign flood on the 1iver.
SINKHOLES
Geologically yo ung sinkho les are present in the western Colorado evaporite region
mostly in areas where the Eagle Valley Formation and Eagle V alley Evaporite are
sh allow, see Figure 3. In this region a few sinkho les have collapsed at the gro und s urface
with little or no warning during historic times. This indicates that infrequent sinkhole
formation is st ill an active geo logic process in the region. Evidence of sinkholes was no t
o b served at the project site during our fi e ld reconnaissance or aeri a l photographs review
but could have been obscured by the snow cover. A field review to lo ok for sinkho les in
the proposed building area should be made after the site is clear of snow cover. Alth ough
geologically active in the region , the lik e lihood that a sinkho le wi ll development during a
reaso nable exposure time at the project area is considered to be low. This inference is
Job No. I 06 0920 ~tech
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based on the large extent of sinkhole prone areas in the region in comparison to the small
number of sinkholes that have developed in historic times.
Because of the complex nature of the evaporite related sinkholes, it will not be possible to
avoid all sinkhole risk at the project site. If conditions indicative of sinkhole related
problems are encountered during site specific soil and foundation studies for the houses
and other movement sensitive faculties, an alternative building site should be consid ered
or the feas ibility of mitigation evaluat ed. Mitigation measures cou ld include : (1) a rigid
mat foundation, (2) stab ili zation by grouting, (3) stabilization b y excavation and
backfilling, (4) a deep foundatio n system or (5) structural bridging. Water features
should not be considered c lose to building sit es, unless evaluated on a site specifi c basis.
The home owners could purchase special insurance to reduce their potential risks.
Prospective owners should be adv ised of the sinkhole potential, since early detection of
building distress and timely remedial actions are import ant in reducing the cost of
building repair should an undetected subsurface void start to develop into a sinkho le after
construction.
EARTHQUAKE CONSIDERATIONS
Historic earthq uakes within 150 miles of t he project site have typicall y been moderately
strong with magnitudes of M 5.5 and less and maximum Modified Mercalli Intensities of
VI and less , see Figure 2. The largest historic emihquake in the project region occurred in
1882. It was located in the notihem Front Rm1ge about 11 5 miles to the no1iheast of the
project site and had a estimated magnitude of about M 6.2 and a maximum intensity of
VII. Historic ground shaking at the project s ite associated w ith the 1882 m1d the oth er
l arger historic earthquakes in the region does not appem· to have exceeded Modified
Mercalli Intensit y VI (Kfrkham and Rogers, 1985). Modified Mercalli Intensity VI
ground shaking should be expected during a reasonable exposure time for t he houses and
other project facilities , but the probability of stronger ground shak in g is lo w. Intensity
VI ground shaking is felt by most people and causes general alarm, but result s in
negligible damage to structures of good design and construction.
Job No. I 06 0920 ~tech
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The houses and other facilities subject to earthquake damage should be designed to
withstand moderately strong ground shaking with Uttle or no damage and not to collapse
under stronger ground shaking . For.firm rock sites with shear wave velocities of 2,500
fps in the upper 100 feet , the U. S. Geological Smvey 2002 National Seismic Hazard
Maps indicate that a peak ground acceleration of 0.06g has a 10% exceedence probability
for a 50 year exposure time and a peak ground acceleration of 0 .23g has a 2% exceedence
probability for a 50 year exposure time at the project site (Frankel and Others , 2002).
This corresponds to a statistical recmTence time of about 500 years and 2,500 years,
respectively. The soil profiles at the building sites should be considered as Class C ,finn
rock sites as described in the 2006 International Building Code unless site specific shear
wave v elocity studies show otherwise.
RADIATION POTENTIAL
Regional studies by the Colorado Geo logical Survey indicate that the clo sest radioactive
mineral occmTences to the project site are greater that twenty miles from the site
(Nelson-Moore and Others, 1978). Radioactive mineral occurrences are present in the
Aspen-Lenado mining district to the southeast and on the southwest flank of the White
River uplift to the northwest. Regional studies by the U. S . Geological Survey (Dubiel,
1993) for the U.S. Environmental Protection Agency (EPA) indicate that the project site
is in a moderate radon gas potential zo ne . The 1993 EPA r egio nal radon study considered
data from (1) indoor radon surveys, (2) aerial radioactivity surveys, (3) the general
geology, ( 4) soil permeability estimates, and (5) regio nal architectural practices. It is not
possible to accurately assess future radon concentrations in buildings before they are
constructed. Accurate t ests ofradon concentrations can only be made when the buildings
have been comp leted. Because of this, new buildings in moderate to high radon areas are
often designed with provisions for ventilation of the lower enclo sed areas should post
construction tes ting show unacceptabl e radon concentrations.
Job No. I 06 0920 ~tech
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FIELD EXPLORATION
The field exploration for the project was conducted on January 10 and 15 , 2008. Twelve
exploratory pits were excavated at the locations shown on Figure 5 to evaluate the
subsurface conditions. The pits were dug with a trackhoe and were logged by a
representative of Hepworth-Pawlak Geotechnical, Inc. Samples of the subsoils were
taken with relatively undisturbed and disturbed sampling methods . Depths at which the
samples were taken are shown on the Logs ofExploratmy Pits, Figure 6. 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 6.
The subsoils consist of about ½ to 3 feet of organic topsoil overlying 2 feet of silty sand
in Pit 1 and relatively dense, silty sandy gravel containing cobbles and boulders in the
remaining pits. Pit 3 contained a lens of slightly gravelly sand from 4 to 5 ½ feet.
Laborat01y testing performed on samples obtained from the pits included natural moisture
content and density and gradation analyses. Results of swell-consolidation testing
performed on a relatively undisturbed sample, presented on Figure 8, indicate moderate
compressibility under conditions ofloading and wetting. Results of gradation analyses
performed on large disturbed samples (minus 3 to 5 inch fraction) of the natural coarse
granular soils are shown on Figures 9 through 12. The laboratory testing is summarized
in Table I.
No free water was encountered in the pits at the time of excavation and the subsoils were
slightly moist.
PRELIMINARY DESIGN RECOMMENDATIONS
The conclusions and recommendations presented below are based on the proposed
development, subsurface conditions encountered in the exploratory pit, and our
experience in the area. The recommendations are s uitable for planning and preliminary
design but site specific studies should be conducted for indiv idual lot development.
Job No. I 06 0920 ~tech
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FOUNDATIONS
Bearing conditions will vary depending on the specifi c lo cation of the building on the
property. Based on the nature of the proposed construction, spread footings bearing on
the natural granular soils should be suitable at the building sites. We expect the footings
can be sized for an allowable bearing pressure in the range of 1,500 psf to 3,000 psf
Compressible silty sands encountered in building areas may need to be removed or the
footings designed accordingly as paii of the site specific lot study. Nest ed boulders and
loose matrix soils may need treatment such as enlarging footings or placing compacted
structural fill. Foundation wall s should be designed to span local anomalies and to resist
lateral earth loadings when acting as retaining structures. The footings should have a
minimum depth of 36 inches for fro st protection.
BELOW GRADE CONSTRUCTION
Free water was enco untered in some of the exploratory pits and it has been our experience
in the area that the water level can rise and local perched groundwater can develop during
times of seasonal runoff and heavy inigation. In general, all below grade areas sho u ld be
protected from wetting and hyd ro static pressure buildup by use of an underdrain system.
We recommend that slab-on-grade floors be placed near to above existing grade and
crawlspaces be kept shallow. Basement leve ls may not be feasible in the lower lying
ai·eas with a shallo w groundwater level. Potential gro undwater impacts on proposed
development sho uld be evaluated as part of the site spec ifi c building stud y.
FLOOR SLABS
Slab-on-grade construction should be feasible for bearing on the natural granulai· soils
below the topsoil. There could be some post construction slab settlement at sites with
compressible s ilts and sands. To reduce the effects of some differential movement, floor
slabs should be separated from all bearing walls and co lumns with expansion joints.
Floor slab co ntrol joints should be used to reduce damage due to shrinkage cracking. A
Job No, I 06 0920 ~tech
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minimum 4 inch thick layer of free-draining gravel should underlie building slabs to
break capillary water rise and facilitate drainage.
SURFACE DRAJNAGE
The grading plan for the subdivision should consider runoff through the project and at
individual sites. Water should not be allowed to pond next to buildings. To limit
infiltration into the bearing soils next to buildings, exterior backfill should be well
compacted and have a positive slope away from the building for a distance of at least 10
feet. Roof downspouts and drains should discharge well beyond the limits of all backfill
and landscape inigation should be restricted.
PAVEMENT SECTION
The near surface soils encountered in the exploratory pits below the topsoi l typically
consisted of si lt y sandy gravel. The pavement section for the site access roads can be
taken as 3 inches of asphalt pavement on 8 inches of Class 6 aggregate base course for
preliminary design purposes. The subgrade should be evaluated for pavement support at
the time of construction. Subexcavation of the topsoil and fine-grained soils and
rep lacement with coarse granular sub base material may b e needed to achieve a stable
subgrade in some areas.
LIMITATIONS
This study has been conducted according to generally accepted geotechnical e ngineering
principles and practices in this area at this time. We make no warranty either express or
implied. The conclusions and recommendations submitted in this repo1t are based upon
the data obtained from the field reconnaissance, review of published geologic reports, the
exploratory pits located as shown on Figure 5 and to the depths sho wn on Figure 6, the
proposed type of con struction and our experience in the area. Our consulting services do
not include determining the presence, prevention or possibility of mold or othe r 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
Job No. I 06 0 920 ~tech
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include interpolation and extrapolation of the subsurface conditions identified and the
exploratory pits and variations in the subsurface conditions may not become e vident 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 planning and
preliminary design purposes. We are not responsible for technical interpretations by
others of our information. As the project evolves , we sho uld provide continued
consultation, conduct addition al evaluations and review and monitor the implementation
of our recommendations. 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 t esting of structural fill by a
representative of the geotechnical engineer.
Respectfully Submitted,
HEPWORTH -PAWLAK GEOTECHNICAL, INC.
Scott W. Richards, E.I.
Reviewed by:
Steven L. Pawlak, P.E .
SWR/vad
Job No. 106 0920 ~tech
-12 -
REFERENCES
Dubiel , R. F., 1993 , Preliminary Geologic Radon Potential Assessment of Colorado in
Geologic Radon Potential EPA R egion 8, Colorado, Montana, North Dakota,
South Dakota, Utah and Wyoming: V. S. Geological Survey Open File Report 93 -
292-H.
Frankel, A. D. and Others, 2002, Documentation for the 2002 Update of the National
Seismic Hazard Maps: V. S. Geological Survey Open File Report 02-420.
Kirkham, R. M. and Rogers, W. P., 1985, Colorado Earthquake Data and Interpretations
1867 to 1985: Co lorado Geological Survey Bulletin 46.
Kirkham, R. M. and Widmann, B. L., 1997, Geology Map of the Carbondale Quadrangle,
Garfield County, Colorado: Colorado Geological Survey Open File 97-3 .
Kirkham, R. M. and Scott, R. B., 2002, Introduction to Late Cenozoic Evaporite
Tectonism and Volcanism in West-Central, Colorado , in Kirkham R. M., Scott, R.
Job No. I 06 0920 ~tech
Moisture Content = 8 .9 p ercent
Dry Density = 96 pct
Sample of: Si lty Sand
Fro m : Pit 1 at 2 ½ Feet
0
v L...-t? L.--l/ 1 ---,
i.--V Compression
( upon
2
wetti ng
I 1
3 \
?fi. \ C 4 0 \ "iii en
(1)
0.
E 5 \
0 \ u
6 I
i l
7 \
\
8 \
\
)
9
0.1 1.0 10 100
APPLI ED PR ESSUR E -ksf
106 0920 ~ SWELL -CON SOLI DATI ON TEST RESULTS Figure 8
Heo worth-Powlok Geot echnlcol
HYDROMETER ANALYSIS SIEVE ANALYSIS
I TIME READINGS I U.S . STANDARD SERIES I CLEAR SQUARE OPEN INGS I
24 HR. 7 HA
3/8' 3/4' 1 1/2' 3" 5'6' 8' 45 MIN . 15 MIN . 60MINl9MIN.4 MIN. 1 MIN. #200 #100 #50 #30 #16 #8 #4
0 100
10 I 90
,'
0 20 80
w (.')
z 30 70 z
<( u5
I-I Cf)
w 40 60
<(
a: I 0..
I-I-
z 50 50 z
w w
0 0
a: 60 40 a:
w w
0.. 0..
70 30
80 20
90 -10 -
100 0
.()()1 .002 .005 .009 .019 .037 .074 .150 .300 .600 1.18 2.36 4.75 9.5 12.5 19.0 37.5 76.2 152 203
127
DIAMETER O F PARTICLES IN MILLIMETERS
CtAYTOSILT I SAND GRAVEL I COBBl.ES I FINE I MEDIUM !COARSE I FINE I COARSE I
GRAVEL 66 % SAND 32 % SILT AND CLAY 2 %
LIQUID LIMIT % PLASTI CITY INDEX %
SAMPLE OF: Sandy Gr ave l FROM: Pit 2 at 8 to 8 ½ Feet
HYDROMETER ANALYSIS SIEVE ANALYSIS
24 ~-A. 7 HR TIME READINGS I U.S. STANDARD SERIES I CLEAR SQUARE OPENINGS I
45 MIN . 15 MIN . 60MINJ9MIN.4 MIN . 1 MIN. #200 #100 #50 #30 #16 #8 #4 3/8" 3/4" 1 1/2' 3' 511 5 11 8"
0 100 -10 -90 -
0 20 80
w (.')
z 30 70 z
<( u:i
I-Cf)
w 40 60 <(
a: 0..
I-I-z 50 50 z w w
0 0
a: 60 40 ffi w
0.. 0..
70 30
80 20
90 I 10
100 0
.001 .002 .005 .009 .019 .037 .074 .150 .300 .600 1.18 2 .36 4.75 9.51 2.5 19.0 3 7.5 76.2 121,52 203
DIAMET ER OF PARTICLES IN MILLIMETERS
CLAY TO SILT SAND I GRA\/El I COBBLES FINE I MEDIUM !COARSE I Fl >£ I COARSE I
GRAVEL 15 % SAND 83 % SILT AND CLAY 2 %
LIQU ID LIMI T % PLASTICITY INDEX %
SAMPLE OF: Sandy Gravel FROM: Pit 3 at 5 to 5 ½ Feet
106 0920 ~
Hepworth -Powlok Geotechnlcal
GRADATI ON TEST RES ULTS Fig ure 9
HYDROMETER ANALYSIS SIEVE ANALYSIS
I TIME READINGS l U.S. STANDARD SERIES I CLEAR SQUARE OPENINGS I
24 HR. 7HR 3/8' 3/4" 1 1/2" 3" 5'6" 8'
45 MIN. 15 MIN. 60MIN19MIN.4 MIN. 1 MIN. #200 #100 #50 #30 #16 #8 #4 100
0
10 90
20 80
0 C)
w z 30 70 z
<( u5
U)
I-<( w 40 60
a:
(l_
I-
I-z 50 50 z
w w
0
0
a: 60 ,o a:
w w
(l_
(l_
70 30
80 20
90 10
100 0
.001 .002 .005 .009 .019 .037 .074 .150 .300 .600 1.18 2.36 4.75 9.5 12.5 19.0 37.5 76 .2 152 203
127
D IAMETER OF PARTICLES IN MILLIMETERS
CLAY TO SILT SAND GRAVEL I COBBLES
FINE I MEDIUM I COARSE FINE I COARSE I
GRAVEL 69 % SAND 29 % SI LT A ND CLAY 2 %
LI QUID LIM IT % PLASTIC ITY IN DEX %
SAMPLE OF: Sandy Gravel FROM: Pit 4 at 8 ½ to 9 Feet
HYDROMETER ANALYSIS SIEVE ANALYSIS
24 ~R 7HR
TIME READINGS l U.S. STANDARD SERIES I CLEAR SQUARE OPENINGS I
45 MIN. 15 MIN. 60MIN19MIN.4 MIN. 1 MIN. #200 #100 #50 #30 #16 #8 #4 3/8" 3/4" 1 1/2" 3" 511511 8"
0
100
10 90
0 20 80
C) w z 30 70 z
<( u5
I-
U)
w 40 60 <(
a: I
(l_
I-
I-z 50 50 Z
w w
0
. 0
a: 60
,.
40 ffi
w
(l_
(l_
70 30
80 20
90 10
~
100 0
.001 .002 .005 .009 .019 .037 .074 .150 .300 .600 1.18 2.36 4.75 9-512.5 19.0 37 .5 76.2 12}52 203
DIAMETER OF PARTICLES IN MILLIMETERS
CLAY TO SILT I SAND I GRAVEL I
I FINE I MEDIUM I COAASE I FINE I COARSE 7 COBBLES
GRAVEL 73 % SAND 25 % SILT AND CLAY 2 %
LIQUID LIMIT % PLASTICITY INDEX %
SAMPLE OF: Sandy Gravel FROM: Pit 6 at 8 ½ to 9 Feet
106 0920 ~
Hepworth-Pawlak Gea technical
GRADATI ON TEST RES ULTS Figure 10
HYDROMETER ANALYS IS SIEVE ANALYSIS
I TIME READ INGS I U.S. STANDARD SERIES I CLEAR SQUARE OPEN INGS I
24 HA. 7 HR 3/8" 3/4" 1 1/2" 3' 5"6' 8"
45 MIN. 15 MIN. 60MIN19MIN4 MIN. 1 MIN . #200 #100 #50 #30 #1 6 #8 #4
0
100
10 90
20 80
0 (.')
w z z 30 70 u5 <{ Cf)
f-<( w 40 80
a: 0....
f-
f-z 50 50 z w w u u a: a: 60 40 w w 0....
0...
70 30
80 20
90 10 -
100 0
.001 .002 .005 .009 .01 9 .037 .074 .150 .300 .600 1.18 2.36 4.75 9.5 12.5 19.0 37.5 76.2 152 203
127
DIAMETER OF PARTICLES IN MILLIMETERS
I SAND GRAVEL I COBBLES ClAYTO SILT I FINE I MEDIUM I COARSE FINE I COARSE I
GRAVEL 61 % SAND 36 % SILT AND CLAY 3 %
LIQUI D LI MIT % PLASTICITY IN DEX %
SAMPLE OF: Sandy Gravel FROM : Pit 8 at 7 ½ to 8 ½ Feet
HYDROMETER ANALYSIS SIEVE ANALY SIS
~
. TIME READINGS I U.S. STANDARD SERIES I CLEAR SQ UARE OPENINGS I
24 R. 7 HR 3/8" 3/4" 1 1/2" 3" 5'6" 8'
45 M IN. 15 MIN. 60MIN19MIN.4 MIN. 1 MI N . #200 #100 #50 #30 #16 #8 #4
0 100
10 90
20 80
0 (.') w z 30 70 z
<{ I u5
Cf)
f-, <( w 40 60
a: , 0....
f-, f-
z 50 50 ti]
w u -u
a: 60 40 a:
w w
0.... 0....
70 30
~
80 20
,
90 10
-
100 0
.001 .002 .005 .00 9 .019 .037 .074 .150 .300 .600 1.18 2 .36 4.75 9 51 2 ,5 19.0 37.5 76.2 12}52 203
DIAMETER OF PARTI CLES IN MILLIMETERS
ClAYTO SILT I SANO I GRAVEL I COBBLES
I FINE I MEDIUM I COARSE I FINE I COARSE I
GRAVEL 54 % SAND 41 % SILT AND CLAY 5 %
LIQUID LIMIT % PLASTIC ITY INDEX %
SAMPLE OF: Sandy Gravel with Cobbl e FROM : Pit 10 at 6 ½ to 7 Feet
106 0920 ~ GRADATION TEST RESULTS Figure 11
Heowor th-Powlok Geotechn lcol
0 w z
<(
f-w
0::
f-z w
0
0:: w a...
HYDROMETER ANALYSIS SIEVE ANALYSIS
I TIME READINGS
24 HR. 7 HR
O 45 MIN. 15 MIN . 60MIN19MIN.4 MIN. 1 MIN. #200 #100 #50 #30
I U.S. STANDARD SERIES
#16 #8
I
#4
CLEAR SQUARE OPEN INGS
3/8" 3/4' 1 1/2" 3" 5" 6"
I
8" 100
90
10
80
20
70
30
60
40
50
50
,
40
60 ,
30
70
20
80
10
90
0
100
.001 .002 .005 .009 .019 .037 .074 .150 .300 .600 1.18 2 .36 4.75 9.5 19.0 37.5 76.2 152 203
12.5 127
DIAMETER OF PARTICLES IN MILLIMETERS
CIAYTOSlLT I
SAND GRAVEL '
I FINE MEDIUM !COARSE FINE I COARSE I COBBLES
GRAVEL 68 % SAND 31 % SILT AND CLAY 1 %
LIQUID LIMIT % PLASTICITY INDEX %
SAMPLE OF: Sandy Gravel FROM: Pit 12 at 7 ½ to 8 Feet
c.,
z
vi
(/)
4'. a...
f-z w
0
0:: w a...
106 0920 ~ GRADATION TEST RESULTS Figure 12
Heoworth-Powlak Geotechnlcal
HEPWORTH-PAWLAK GEOTECHNICAL, INC.
TABLE 1 Job No. 106 0920
SUMMARY OF LABORATORY TEST RESULTS
SAMPLE LOCATION NATURAL GRADATION ATTERBERG LIMITS
MOISTUR NATURAL PERCENT UNCONFINED
E DRY GRAVEL SAN D PASSING LIQUID PLASTIC COM PRESSIVE SOIL OR PIT DEPTH CONTEN DENSITY NO. 200 LIMIT INDEX STRENGTH BEDROCK TYPE T (%) (%) SIEVE
(ft) (%) (pcf) (%) (%) (PSF)
1 2½ 8.9 96 41 Silty sand
2 8-8½ 66 32 2 Sandy g ravel
3 5-5½ 2.7 15 83 2 Gravelly sand
4 8½ - 9 69 29 2 Sandy gravel
6 8½ -9 73 25 2 Sandy gravel
8 7½ -8½ 61 36 3 Sandy gravel
10 6½ -7 54 41 5 Sandy gravel
12 7½ -8 68 31 1 Sandy gravel