HomeMy WebLinkAbout215 MATHEWS OFFICE BUILDING - PDP - PDP150020 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT1501 Academy Ct. Ste. 203 Fort Collins, Colorado 80524 (970) 530-4044
PreliminaryDrainageSummary
215 Matthews Street
Fort Collins, CO
Prepared for:
Scout Leasing, LLC
330 South College Avenue, Suite 300
Fort Collins, CO 80524
October 20, 2015
Drainage Summary
215 Matthews Street
Fort Collins, CO
1 U14012-DrainageSummary-Preliminary.doc
October 20, 2015
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, Colorado 80521
RE: 215 Matthews Street
Fort Collins, Colorado
Project Number: U15007
Dear Staff:
United Civil Design Group, LLC. is pleased to submit this Preliminary Drainage Summary for the
215 Matthews Street site in Fort Collins, Colorado. In general, this summary serves to
document the stormwater impacts associated with the proposed project.
Site Location and Project Description
The 215 Matthews Street development site (referred herein as ”the site”) is located in the
southwest quarter of Section 12, Township 6 North, Range 69 West of the Sixth P.M., City of
Fort Collins, Larimer County, Colorado. The site consists of approximately 7,000 square-feet
(sf) and is bounded by Matthews Street on the east, a public alley on the west, and existing
commercial properties to the north and south. See the attached Drainage Plan for additional
information.
The planned development for the site will consist of the following:
• The construction of multi-story, office building with a proposed footprint of
approximately 4,130 sf (5,060 sf roof footprint) with an enclosed parking garage on the
first floor.
• The construction of utilities to support the proposed building including sanitary, water
and storm drainage.
• The construction of right-of-way improvements including curb and gutter, public
sidewalk and landscaping.
Existing Conditions
Hydrology
The site, which is located within the Old Town Basin, is approximately 7,000 sf in size
and currently consists of an existing one-story residential building, gravel parking area,
and landscape areas with an existing percent-imperviousness of approximately 31%.
Drainage Summary
215 Matthews Street
Fort Collins, CO
2 U14012-DrainageSummary-Preliminary.doc
Storm runoff from the site currently drains towards Matthews Street where runoff is
intercepted by existing curb and gutter which directs the runoff to the north to storm
sewer inlets and piping located near Oak Street. Refer to Appendix A for additional
information.
Floodplain
The site is not located within a FEMA or City-regulatory floodway or floodplain.
Developed Conditions
Hydrology
The developed site will consist of approximately 6,060 square feet of impervious area
including roof, pavement and sidewalk. This is an increase of approximately 2,994
square feet of impervious area. The following table summarizes the changes of the site
from existing to proposed conditions. Refer to the Drainage Plan and Hydrology
calculations for additional information.
Comparison Summary Table
Existing
Site
Proposed
Site
Overall Area (sf) 7,000 7,000
Roof (sf) 1,321 5,060
Concrete (sf) 703 1004
Gravel (sf) 627 0
Landscape (sf) 4,349 935
Total Impervious Area (sf) 2,651 6,064
% Imperviousness 31% 78%
The drainage patterns for the proposed condition will remain largely unchanged
from existing conditions in that the vast majority of the drainage from the site will
be directed towards Matthews Street. It is anticipated that no additional drainage
area will be directed towards the west and the public alley with the proposed
development.
Storm Sewer
The proposed improvements do not require any proposed storm sewer. The site will be
using raised bioretention planter boxes for water quality which will daylight at grade
and therefore wil not require a storm sewer system.
Drainage Summary
215 Matthews Street
Fort Collins, CO
3 U14012-DrainageSummary-Preliminary.doc
Detention and Water Quality Requirements
The proposed improvements will increase the total impervious area less than 5,000
square feet from existing conditions; therefore, stormwater quantity detention is not
required.
The Udall Natural Area provides water quality treatment for 50% of the site; however,
the City encourages additional water quality onsite. The development is proposing to
provide additional water quality measures in the form of bioretention planter boxes
that will collect approximately 3,815 square feet of the roof area prior to releasing to
Matthews Street.
Low Impact Development (LID) Requirements
In February of 2013, City Council adopted the LID policy and criteria. The proposed
development is required to meet the newly adopted criteria. Per the criteria, the site
must:
• Treat no less than 50% of any newly added impervious area using one or a
combination of LID techniques.
• Treat no less than 25% of any newly added pavement area using a permeable
pavement.
The following measures are being implemented with this proposed development:
Bioretention Planters
Basins A2-A3 and B2 (with 3,815 sf of impervious roof area) will be routed
through bioretention planter boxes that will collect roof drainage from the
building downspouts being designed with this project. The bioretention planters
have average depths of 9-inches with an overall volume of 106 cubic feet which
exceeds the minimum design requirements for the area. Refer to the Appendix
for additional calculations.
Permeable Pavers
Due to the small amount of added pavement not covered by roof (approximately
850 sf), and per communication with City staff, this site is not being required to
provide permeable pavers.
In total, the development is proposing to collect and treat 3,815 sf (62.9%) of the
overall 6,064 sf of impervious area developed with this project. In addition, the
site is also being designed with other various open landscaped areas and
vegetated swales to provide additional water quality in addition to the areas
being treated with bioretention.
Drainage Summary
215 Matthews Street
Fort Collins, CO
4 U14012-DrainageSummary-Preliminary.doc
Four Step Process
With the adoption of the USDCM, the City has also adopted the “Four Step Process”
that is recommended in Volume 3 of the USDCM in selecting structural BMPs for the
redeveloping urban areas. The following portions of this summary describe each step
and how it has been utilized for this project:
Step 1 – Employ Runoff Reduction Practices
The objective of this step is to reduce runoff peaks and volumes and to employ the
technique of “minimizing directly connected impervious areas” (MDCIA). This project
accomplishes this by:
• Routing roof flows through bioretention planter boxes and through vegetated
swales to increase time of concentration, promote infiltration and provide
water quality.
Step 2 – Provide Water Quality Capture Volume (WQCV)
The objective of providing WQCV is to reduce the sediment load and other pollutants
that exit the site. For this project WQCV is provided within the Udall Natural Area, so
no additional WQCV is required. However, the development is providing bioretention
planter boxes; and therefore, additional WQCV in order to satisfy the LID requirements.
Step 3 – Stabilize Drainageways
The site is not adjacent or near a major drainageway; however, this project will pay
stormwater development and stormwater utility fees which the City uses, in part, to
maintain the stability of the City drainageway systems.
Step 4 – Consider Need for Industrial and Commercial BMPs
This step is generally considered for industrial and commercial sites. As this
development is proposing a small office building, no specialized BMPs have been
considered for this project.
Standard Operating Procedures (SOPs)
In order for physical stormwater Best Management Practices (BMPs) to be effective,
proper maintenance is essential. Maintenance includes both routinely scheduled
activities, as well as non-routine repairs that may be required after large storms, or as a
result of other unforeseen problems. Standard Operating Procedures should clearly
identify BMP maintenance responsibility. BMP maintenance is typically the
responsibility of the entity owning the BMP.
Identifying who is responsible for maintenance of BMPs and ensuring that an adequate
budget is allocated for maintenance is critical to the long-term success of BMPs.
Maintenance responsibility may be assigned either publicly or privately. For this
project, the privately owned BMPs shown in Appendix D of this Addendum are to be
Drainage Summary
215 Matthews Street
Fort Collins, CO
5 U14012-DrainageSummary-Preliminary.doc
maintained by the property owner, homeowner’s association (HOA), or property
manager.
Erosion Control
Erosion control, both temporary and permanent, is a vital part of any development project.
For this project, the site disturbance will be less than 10,000 sf; therefore, comprehensive
erosion control measures have been included within the Grading and Erosion Control Plan for
the project. Refer to the Utility Plans, under separate cover, for additional information.
Conclusions
In conclusion, the drainage system proposed within this Drainage Summary provides adequate
conveyance of the developed stormwater runoff from the proposed development to existing
discharge locations and drainage systems. It should also be noted that with this summary and
the corresponding design, every attempt has been made to minimize any negative impacts on
the downstream receiving waters. With the incorporation of the LID techniques, the site will
discharge a lower sediment load and less runoff.
We understand that review by the City of Fort Collins is to assure general compliance with
standardized criteria contained in the Fort Collins Stormwater Criteria Manual (FCSCM). This
addendum was prepared in compliance with technical criteria set forth in both the Urban
Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual and the
FCSCM.
If you should have any questions or comments as you review this drainage summary, please
feel free to contact us at your convenience.
Sincerely,
United Civil Design Group, LLC
Kevin Brazelton, PE
Engineering Manager
APPENDICES
APPENDIX A - Hydrology Computations
APPENDIX B - LID Calculations
APPENDIX C - Standard Operating Procedures (Reserved for Final Submittal)
APPENDIX D – Referenced Material
APPENDIX E - Drainage Plan
APPENDIX A
Hydrology Calculations
215 Matthews Street
Fort Collins, Colorado Impervious Area Summary
Roof
(1)
Concrete
(1)
Gravel
(1) Permeable
Pavers
(1) Landscape
(1)
%I = 90% %I = 90% %I =40% %I =20% %I=2%
acres sf sf sf sf sf sf C2
C100
Existing 0.16 7000.0 1321 703 627 0 4349 30.8% 0.47 0.59
Proposed 0.16 6999.0 5060 1004 0 0 935 78.2% 0.86 1.00
Difference 0.0 -1.0 3739 301 -627 0 -3414 47.4% 0.38 0.41
(1) Recommended % Imperviousness Values from USDCM Vol 1 - Ch 5 - Table RO-3. Increased Lawns from 0% to 2% Impervious.
(2) Runoff C is based on %I, UDFCD Eq RO-7 and correction factors in Table RO-4.
Basin
Areas
Composite
Imperviousness
(%I)
Total Total Composite Runoff Coefficients
(2)
Calculations by: KRB
Date: 10/14/2015 C:\United Civil\Dropbox\Projects\U15007 - 215 Mathews\Drainage\Hydrology\U15007-Runoff.xlsx
215 Matthews Street
Fort Collins, Colorado Runoff Coefficients and % Impervious
Roof
(1) Asphalt Concrete
(1)
Gravel
(1) Permeable
Pavers Landscape
(1)
%I = 90% %I = 100% %I = 90% %I =40% %I=20% %I=2%
acres sf sf sf sf sf sf sf C2 C
100
EX-1 EX-1 0.16 7000 1321 703 627 4349 30.8% B 0.47 0.59
0.16 7000 1321 0 703 627 0 4349 31% 0.47 0.59
A1 A1 0.02 963 499 464 47.6% B 0.61 0.77
A2 A2 0.03 1284 1284 0 90.0% B 0.95 1.00
A3 A3 0.03 1259 1259 0 90.0% B 0.95 1.00
B1 B1 0.02 976 505 471 47.5% B 0.61 0.77
B2 B2 0.03 1272 1272 0 90.0% B 0.95 1.00
B3 B3 0.03 1245 1245 0 90.0% B 0.95 1.00
Onsite Total 0.16 6999 5060 0 1004 0 0 935 78% B 0.86 1.00
Notes:
(1) Recommended % Imperviousness Values from USDCM Vol 1 - Ch 5 - Table RO-3. Increased Lawns from 0% to 2% Impervious.
(2) Runoff C is based on %I, UDFCD Eq RO-7 and correction factors in Table RO-4.
Proposed Basins
Existing Basins
Onsite Total
Basin
Areas
Composite
Imperviousness
(%I)
Design Pt. Total Total
Composite Runoff
Coefficients
NRCS Soil (2)
Type
Calculations by: NKS
Date: 10/14/2015 C:\United Civil\Dropbox\Projects\U15007 - 215 Mathews\Drainage\Hydrology\U15007-Runoff.xlsx
215 Matthews Street
Fort Collins, Colorado Time of Concentration
Area Length Slope ti
(2) Length Slope Velocity (3) tt
(4) Check tc? Total
Length tc
(5)
acres ft % min ft % fps min min Urban? ft min min
EX-1 EX-1 0.2 Roof 0.73 25 2 2.6 75 1 15 1.5 0.8 3.5 Yes 100 11 5
A1 A1 0.0 Paved 0.90 35 2 1.7 110 0.5 20 1.4 1.3 3.0 Yes 145 11 5
A2 A2 0.0 Roof 0.73 20 2 2.4 50 1 20 2.0 0.4 2.8 Yes 70 10 5
A3 A3 0.0 Roof 0.73 20 2 2.4 50 1 20 2.0 0.4 2.8 Yes 70 10 5
B1 B1 0.0 Paved 0.90 35 2 1.7 110 2 20 2.8 0.6 2.3 Yes 145 11 5
B2 B2 0.0 Roof 0.73 20 2 2.4 50 1 15 1.5 0.6 2.9 Yes 70 10 5
B3 B3 0.0 Roof 0.73 20 2 2.4 50 1 15 1.5 0.6 2.9 Yes 70 10 5
Notes:
(1)
C5 based initial ground type and Table RO-5
(4)
tt=L/(V*60 sec/min)
(2)
ti = [1.8(1.1-C
5)L
1/2
]/S
1/3
, S= slope in %, L=length of overland flow (400' max)
(5)
tc check (for urban or developed areas only) = total length/180 + 10
(3)
V=CvS
0.5
, S=watercourse slope in ft/ft, UDFCD Equation RO-4
(6)
min tc = 5 min
Proposed Basins
Existing Basins
Initial
Ground
Type
C5
(1) Cv
ti+tt Final tc
(6)
tc Check for Urbanized
Basin
Initial Overland Flow Time (ti) Travel/Channelized Time of Flow (tt)
Design Pt.
Calculations by: NKS
Date: 10/14/2015 C:\United Civil\Dropbox\Projects\U15007 - 215 Mathews\Drainage\Hydrology\U15007-Runoff.xlsx
215 Matthews Street
Fort Collins, Colorado Rational Method Peak Runoff
Final
tc
(6) I2 I100 Q2 Q100
acre min in/hr in/hr cfs cfs
EX-1 EX-1 0.2 5 0.475 0.593 2.85 9.95 0.22 0.95
0.22 0.95
A1 A1 0.0 5 0.613 0.766 2.85 9.95 0.04 0.17
A2 A2 0.0 5 0.950 1.000 2.85 9.95 0.08 0.29
A3 A3 0.0 5 0.950 1.000 2.85 9.95 0.08 0.29
B1 B1 0.0 5 0.612 0.765 2.85 9.95 0.04 0.17
B2 B2 0.0 5 0.950 1.000 2.85 9.95 0.08 0.29
B3 B3 0.0 5 0.950 1.000 2.85 9.95 0.08 0.28
0.39 1.49
Totals
Totals
Peak Discharge
Proposed Basins
Existing Basins
Design Pt. Area
Basin
C100
Runoff Coefficients Rainfall Intensity
C2
Calculations by: NKS
Date: 10/14/2015 C:\United Civil\Dropbox\Projects\U15007 - 215 Mathews\Drainage\Hydrology\U15007-Runoff.xlsx
APPENDIX B
LID Calculations
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 90.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.900
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.32 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 3,815 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 102 cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCVOTHER = cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCVUSER = cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum) DWQCV = 9 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 0.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin = 68 sq ft
D) Actual Flat Surface Area AActual = 141 sq ft
E) Area at Design Depth (Top Surface Area) ATop = 141 sq ft
F) Rain Garden Total Volume VT= 106 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y = ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = N/A cu ft
iii) Orifice Diameter, 3/8" Minimum DO = N/A in
Design Procedure Form: Rain Garden (RG)
KRB
United Civil Design Group
October 14, 2015
215 Matthews Street
Fort Collins
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.03.xlsm, RG 10/14/2015, 3:01 PM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
KRB
United Civil Design Group
October 14, 2015
215 Matthews Street
Fort Collins
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
UD-BMP_v3.03.xlsm, RG 10/14/2015, 3:01 PM
APPENDIX C
Standard Operating Procedures (Reserved for Final Submittal)
APPENDIX D
Referenced Material
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
Larimer County
Area, Colorado
215 Matthews Street
Natural
Resources
Conservation
Service
May 14, 2015
8
Custom Soil Resource Report
Soil Map
4492520 4492580 4492640 4492700 4492760 4492820 4492880
4492520 4492580 4492640 4492700 4492760 4492820 4492880
493470 493530 493590 493650 493710 493770 493830 493890 493950 494010
493470 493530 493590 493650 493710 493770 493830 493890 493950 494010
40° 35' 12'' N
105° 4' 38'' W
40° 35' 12'' N
105° 4' 13'' W
40° 35' 0'' N
105° 4' 38'' W
40° 35' 0'' N
105° 4' 13'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 100 200 400 600
Feet
0 35 70 140 210
Meters
Map Scale: 1:2,620 if printed on A landscape (11" x 8.5") sheet.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
Map Unit Legend
Larimer County Area, Colorado (CO644)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
35 Fort Collins loam, 0 to 3 percent
slopes
7.6 25.3%
94 Satanta loam, 0 to 1 percent
slopes
22.4 74.7%
Totals for Area of Interest 30.0 100.0%
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 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
Custom Soil Resource Report
10
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
11
Larimer County Area, Colorado
35—Fort Collins loam, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: 2tlnc
Elevation: 4,020 to 6,730 feet
Mean annual precipitation: 14 to 16 inches
Mean annual air temperature: 46 to 48 degrees F
Frost-free period: 143 to 154 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Fort collins and similar soils: 85 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Fort Collins
Setting
Landform: Interfluves
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Pleistocene or older alluvium derived from igneous, metamorphic
and sedimentary rock and/or eolian deposits
Typical profile
Ap - 0 to 4 inches: loam
Bt1 - 4 to 9 inches: clay loam
Bt2 - 9 to 16 inches: clay loam
Bk1 - 16 to 29 inches: loam
Bk2 - 29 to 80 inches: loam
Properties and qualities
Slope: 0 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Low
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 in profile: 12 percent
Salinity, maximum in profile: Nonsaline (0.1 to 1.0 mmhos/cm)
Sodium adsorption ratio, maximum in profile: 0.5
Available water storage in profile: High (about 9.1 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability classification (nonirrigated): 4c
Hydrologic Soil Group: C
Ecological site: Loamy plains (R067BY002CO)
Custom Soil Resource Report
12
94—Satanta loam, 0 to 1 percent slopes
Map Unit Setting
National map unit symbol: jpyc
Elevation: 4,800 to 5,600 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Satanta and similar soils: 85 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Satanta
Setting
Landform: Terraces
Landform position (three-dimensional): Side slope, tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Mixed alluvium and/or eolian deposits
Typical profile
H1 - 0 to 12 inches: loam
H2 - 12 to 18 inches: loam, clay loam, sandy clay loam
H2 - 12 to 18 inches: loam, clay loam, fine sandy loam
H2 - 12 to 18 inches:
H3 - 18 to 60 inches:
H3 - 18 to 60 inches:
H3 - 18 to 60 inches:
Properties and qualities
Slope: 0 to 1 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well 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: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 10 percent
Available water storage in profile: Very high (about 26.4 inches)
Interpretive groups
Land capability classification (irrigated): 1
Land capability classification (nonirrigated): 3c
Hydrologic Soil Group: B
Custom Soil Resource Report
13
GEOTECHNICAL SUBSURFACE EXPLORATION REPORT
PROPOSED OFFICE BUILDING
215 MATTHEWS STREET
FORT COLLINS, COLORADO
Prepared By:
SOILOGIC, Inc.
Job Number: 15-1056
April 7, 2015
Geotechnical Subsurface Exploration Report
Proposed Office Building
215 Matthews Street
Fort Collins, Colorado
Soilogic # 15-1056
10
order to maintain flooring product manufacturer warranties. A vapor barrier would help
reduce the transmission of moisture through the floor slabs. However, the unilateral
moisture release caused by placing concrete on an impermeable surface can increase slab
curl. The amount of slab curl can be reduced by careful selection of an appropriate
concrete mix. Slab curl cannot be eliminated. We recommend the owner, architect and
flooring contractor consider the performance of the slabs in conjunction with the
proposed flooring products to help determine if a vapor barrier will be required and
where best to position the vapor barrier in relation to the floor slab. Additional guidance
and recommendations concerning slab-on-grade design can be found in American
Concrete Institute (ACI) section 302.
Pavements Subgrades
At this time, we understand permeable pavements may be utilized for the site drive
and/or parking areas. Permeable pavement subgrades should be developed as outlined in
the “Foundation Bearing and Site Development” portion of this report. Care should be
taken to avoid densification of permeable pavement subgrade soils prior to placement of
the overlying system.
To complete the percolation test for aid in the design, three (3) eight-inch diameter and
36-inch deep percolation test holes were completed at each deep boring location. An
average percolation rate of 57 minutes per inch was established in the near surface site
soils and could be used in design.
With the recommended overexcavation/backfill procedures to develop finish foundation
bearing levels for the proposed building, it is our opinion a Partial of Full-Infiltration
section could be used for this site. The near surface site lean clay is fine graded, such that
a filter fabric should be employed at the clay/filter media interface.
Minimum light and heavy-duty structural permeable pavement section designs are
outlined below in Table I.
Geotechnical Subsurface Exploration Report
Proposed Office Building
215 Matthews Street
Fort Collins, Colorado
Soilogic # 15-1056
11
Table I – Permeable Pavement Section Design
Classification
Roadway
Design Structural Number
Light-Duty
Private Drive/Parking
(2.42)
Heavy-Duty
Private Drive/Parking
(3.08)
Option A – Permeable Pavement
Surface Paver (SF Rima)
Storage Media
Filter Media
(Structural Number)
3.15” (0.40/inch)
*6” (0.11/inch)
6” (0.11/inch)
(2.58)
3.15” (0.40/inch)
*11” (0.11/inch)
6” (0.11/inch)
(3.13)
* The storage media thickness outlined above is from a structural support
perspective only for light-duty pavements. Greater thicknesses may be required
based on storage water calculations and minimum requirements provided by the
system manufacturer.
Light-duty pavements could be considered for light vehicle parking areas. Heavy-
duty pavements should be considered for access drives and other areas of the site
expected to receive heavy trash or delivery truck traffic. We recommend
permeable pavement filter and storage media be adjusted to a workable moisture
content and compacted to at least 75% of the material’s relative density.
Corrosive Soil Characteristics
Water-soluble sulfates (WSS) tests were completed on two (2) selected soil samples
obtained from the site to help evaluate corrosive soil characteristics with respect to buried
concrete. A corrosive soil characteristics outline is included with this report. The WSS
tests fall within the “negligible” and “moderate” classification with respect to the severity
of the sulfate environment. Type II cement should be used for project concrete exposed
to soils with a “moderate” classification. If Type II cement is not available, care should
be taken to thoroughly consolidate concrete exposed to the site soils. A maximum
water/cement ratio of 0.50 is recommended for “moderate” severity. In addition,
consideration could be given to utilizing air-entrained concrete exposed to the site soils,
APPENDIX E
Drainage Plan
9 8 7 6 5 4 3 2 1
B1
B2
A1
A2
A3
PROPOSED BUILDING
PROPERTY LINE 2' CONCRETE PAN
2' CURB CUT
2' CURB CUT
2' SIDEWALK
CHASE
2' SIDEWALK
CHASE
PROPOSED
TRANSFORMER
TRASH ENCLOSURE
(SEE ARCH. PLANS)
100' PUBLIC
RIGHT-OF-WAY
20' PUBLIC
RIGHT-OF-WAY
3' ROOF OVERHANG (TYP.)
PROPERTY LINE
BIORETENTION PLANTER BOX
W/ UNDERDRAIN
BIORETENTION PLANTER BOX PROPERTY LINE
W/ UNDERDRAIN BIORETENTION PLANTER BOX
W/ UNDERDRAIN
PROPOSED SWALE
PROPOSED LANDSCAPE WALL
PREPARED FOR: DATE SUBMITTED:
The engineer preparing these plans will not be responsible
for, or liable for, unauthorized changes to or uses of these
plans. All changes to the plans must be in writing and
must be approved by the preparer of these plans.
CAUTION
215 MATHEWS 10/20/15
U15007
PRELIMINARY
PLANS
NOT FOR CONSTRUCTION
1501 Academy Ct.
Ste. 203
Fort Collins, CO 80524
(970) 530-4044
www.unitedcivil.com
Civil Engineering &
Consulting
215 MATHEWS
7
NONE LAPTOP-5
C:\UNITED CIVIL\DROPBOX\PROJECTS\U15007 - 215 MATHEWS\CADD\CP
C500_DRAINAGE PLAN.DWG
10/14/2015 2:26:15 PM
SME
DRAINAGE PLAN
C500
N/A
10'
7
0 10' 20'
SCALE: 1" = 10'
5'
LEGEND
NOTES
1. EXISTING UNDERGROUND AND OVERHEAD PUBLIC AND PRIVATE UTILITIES AS SHOWN ARE INDICATED ACCORDING TO
THE BEST INFORMATION AVAILABLE TO THE ENGINEER.
2. VEGETATIVE SWALES AND THE BIORETENTION PLANTERS SHALL BE MAINTAINED BY THE PROPERTY OWNER AND FOLLOW
APPLICABLE STANDARD OPERATING PROCEDURES AS SHOWN IN DRAINAGE REPORT FOR 215 MATTHEWS STREET.
LIMITS OF DISTURBANCE
EXISTING CURB & GUTTER
EXISTING CONCRETE
EXISTING BUILDING
EXISTING PROPERTY LINE
EXISTING LOT LINE
EXISTING FENCE
EXISTING GRAVEL
EXISTING PAVEMENT STRIPING
EXISTING WATER
EXISTING SANITARY
EXISTING OVERHEAD ELECTRIC
EXISTING CABLE TV
EXISTING ELECTRIC
EXISTING STORM SEWER
EXISTING GAS
BASIN DESIGNATION
BASIN AREA (ACRE)
2 - YR RUNOFF COEFF.
100 - YR RUNOFF COEFF.
BASIN BOUNDARY
DESIGN POINT
FLOW DIRECTION
EXISTING CONTOUR
PROPOSED CONTOUR
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
APPROVED:
Basin Design Point
Area
%I C2 C100
Q2 Q100
(acre) (cfs) (cfs)
Existing Basins
EX-1 EX-1 0.16 31% 0.47 0.59 0.22 0.95
Proposed Basins
A1 A1 0.02 48% 0.61 0.77 0.04 0.17
A2 A2 0.03 90% 0.95 1.00 0.08 0.29
A3 A3 0.03 90% 0.95 1.00 0.08 0.29
B1 B1 0.02 48% 0.61 0.77 0.04 0.17
B2 B2 0.03 90% 0.95 1.00 0.08 0.29
B3 B3 0.03 90% 0.95 1.00 0.08 0.28
DRAINAGE SUMMARY
the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 9, Sep 22, 2014
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Apr 22, 2011—Apr 28,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
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