HomeMy WebLinkAboutDUTCH BROS - PDP190008 - DOCUMENT MARKUPS - ROUND 2 - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT
Dutch Bros Coffee
Kensington Commons
Prepared for:
M Squared, LLC
1600 East Mulberry St., Unit 1
Fort Collins, CO 80525
Prepared by:
Interwest Consulting Group
1218 West Ash, Suite A
Windsor, Colorado 80550
(970) 674-3300
April 22, 2019
Job Number 1380-165-00
TABLE OF CONTENTS
1. GENERAL LOCATION AND DESCRIPTION ................................................................. 1
1.1 Location ........................................................................................................................... 1
1.2 Description of Property ................................................................................................. 1
1.3 Floodplain Submittal Requirements ............................................................................. 1
2. DRAINAGE BASINS AND SUB-BASINS .......................................................................... 2
2.1 Major Basin Description ................................................................................................ 2
2.2 Sub-basin Description .................................................................................................... 2
3. DRAINAGE DESIGN CRITERIA ....................................................................................... 2
3.1 Regulations ...................................................................................................................... 2
3.2 Directly Connected Impervious Area (DCIA) Discussion .......................................... 2
3.3 Development Criteria Reference and Constraints ...................................................... 4
3.4 Hydrologic Criteria ........................................................................................................ 4
3.5 Hydraulic Criteria .......................................................................................................... 5
3.6 Floodplain Regulations Compliance ............................................................................. 5
3.7 Modifications of Criteria ............................................................................................... 5
4. DRAINAGE FACILITY DESIGN ....................................................................................... 5
4.1 General Concept ............................................................................................................. 5
4.2 Specific Details ................................................................................................................ 5
5. CONCLUSIONS .................................................................................................................... 6
5.1 Compliance with Standards .......................................................................................... 6
5.2 Drainage Concept ........................................................................................................... 6
6. REFERENCES ....................................................................................................................... 7
APPENDIX
APPENDIX A ......................................................................................................................... A
APPENDIX B........................................................................................................................... B
APPENDIX C .......................................................................................................................... C
APPENDIX D ......................................................................................................................... D
APPENDIX E ........................................................................................................................... E
APPENDIX F ........................................................................................................................... F
1
1. GENERAL LOCATION AND DESCRIPTION
1.1 Location
The Dutch Bros Coffee Kensington Commons Development is located in the Southeast
Quarter of Section 35, Township 7 North, Range 69 West of the Sixth Principal Meridian,
in the City of Fort Collins, Larimer County, Colorado. Please refer to the vicinity map in
Appendix A.
The project is Lot 1 and 2 of Kensington Commons and is located north of Jiffy Lube at
121 Kensington Drive. South College Avenue is located to the east and Kensington
Drive is to the north of the property. The property was originally developed for the Jiffy
Lube and a gas station as The Gateway at Harmony P.U.D. First Filing in 1994.
1.2 Description of Property
The site is approximately 0.8 acres of land and will consist of a new building, parking and
drive aisles, and associated sidewalks. The Jiffy Lube will remain on Lot 2.
The site generally slopes in an easterly direction at approximately 3-5%. The land is
currently developed with existing parking and buildings. There are no offsite flows
contributing to the site. The existing flow drains to an existing onsite inlet (containing an
orifice plate) with some parking lot detention (much less than the 1994 design).
According to FEMA Panel 08069C1000F (effective 12/19/2006) there are no mapped
FEMA Floodways on this property, and the property is within Zone X.
Please refer to Appendix F for hydrologic soil and FEMA information.
1.3 Floodplain Submittal Requirements
The project is not within any FEMA or City of Fort Collins mapped floodway. Therefore,
a Floodplain Submittal is not required and a “City of Fort Collins Floodplain Review
Checklist for 50% Submittals” has not been included with this report.
2
2. DRAINAGE BASINS AND SUB-BASINS
2.1 Major Basin Description
The proposed development lies within the Fossil Creek Drainage Basin. The site has
been previously studied in two reports: “Final Drainage Report the Gateway to Harmony
Road P.U.D” (March 9, 1989) and “Final Drainage Report for Lot 1, The Gateway at
Harmony Road P.U.D., First Filing for Jiffy Lube, Inc.” (October 13, 1993) both by
Stewart and Associates, Inc.
2.2 Sub-basin Description
Historically, the site drains to the east where it is collected by an existing inlet and
discharged into an existing storm system in College Avenue and ultimately to the Fossil
Creek channel.
3. DRAINAGE DESIGN CRITERIA
3.1 Regulations
This report was prepared to meet or exceed the “City of Fort Collins Storm Drainage
Design Criteria Manual” specifications. Where applicable, the criteria established in the
“Urban Storm Drainage Criteria Manual” (UDFCD), developed by the Denver Regional
Council of Governments, has been used.
3.2 Directly Connected Impervious Area (DCIA) Discussion
Urban Drainage and Flood Control District (UDFCD) recommends a Four Step Process
for receiving water protection that focuses on reducing runoff volumes, treating the water
quality capture volume (WQCV), stabilizing drainageways and implementing long-term
source controls. The Four Step Process applies to the management of smaller, frequently
occurring events.
3
Step 1: Employ Runoff Reduction Practices
To reduce runoff peaks, volumes, and pollutant loads from urbanizing areas, implement
Low Impact Development (LID) strategies, including Minimizing Directly Connected
Impervious Areas (MDCIA).
Runoff from the majority of this site (parking lot and the existing building) shall drain
directly into a pervious paver system thereby slowing runoff and also promoting
infiltration. Runoff from the remaining northern portion of the site (drive aisle and
proposed building) shall drain directly to a storm system that will release to the subgrade
of the pervious paver system that will slow runoff and increase the time of concentration
and promote infiltration. The project will lower the imperviousness of the site.
Step 2: Implement BMPs that Provide a Water Quality Capture Volume with Slow
Release
Once runoff has been minimized, the remaining runoff shall be treated through the
pervious paver system that allows for settlement of sediments.
Step 3: Stabilize Drainageways
Natural Drainageways are subject to bed and bank erosion due to increases in frequency,
duration, rate and volume of runoff during and following development. Because the site
will drain to an existing storm system, bank stabilization is unnecessary with this project.
Step 4: Implement Site Specific and Other Source Control BMPs
The proposed development will provide the pervious pavement system feature which will
eliminate pollution that had previously been exposed during weathering and runoff
processes. The proposed project will proactively control pollutants at their source by
preventing pollution rather than removing contaminants once they have entered the
stormwater system as compared to historic conditions.
4
3.3 Development Criteria Reference and Constraints
The runoff from this site has been routed to conform to the requirements of the City
Stormwater Department. Water quality capture volume and detention will be provided on
site. The release rate for the site is 0.5 cfs per acre. The site’s water quality will be met
through the use of a pervious pavement system that includes a varying depth of storage in
the voids below the pavers. The impervious area for the site has been reduced from
current condition of 81 percent to proposed condition of 69 percent.
Runoff reduction practices (LID techniques) are also required. No less than fifty percent
of any newly added impervious area must be treated using one or a combination of LID
techniques. The impervious area is 24,021 sf. Basin B contains the pervious paver
system. Using this LID technique, 17,030 sf of impervious area (71%) will be treated
which exceeds the 50% requirement.
No less than twenty five percent of any newly added pavement areas must be treated
using a permeable pavement technology. The project includes 20,902 sf of pavement
area (including sidewalks). This project will incorporate 5,939 of pervious pavers which
is 28% of the pavement exceeds the required 25%.
The pervious pavement system is oversized and provides full detention and water quality
volume for the site.
Please refer to Appendix D for LID calculations and information.
3.4 Hydrologic Criteria
Runoff computations were prepared for the 10-year minor storm and 100-year major
storm frequency utilizing the rational method.
All hydrologic calculations associated with the basins are included in Appendix B of this
report. Standard Form 8 (SF-8) provides time of concentration calculations for all sub-
basins. Standard Form 9 (SF-9) provides a summary of the design flows for all Sub-
basins and Design Points associated with this site.
5
3.5 Hydraulic Criteria
All hydraulic calculations will be presented in the final drainage report and prepared in
accordance with the City of Fort Collins Drainage Criteria.
3.6 Floodplain Regulations Compliance
The project is not within any FEMA or City of Fort Collins mapped floodway. Therefore,
a Floodplain Submittal is not required and a “City of Fort Collins Floodplain Review
Checklist for 50% Submittals” has not been included with this report.
3.7 Modifications of Criteria
There are no Modifications of Criteria for this project.
4. DRAINAGE FACILITY DESIGN
4.1 General Concept
The majority of the proposed development will be collected and conveyed to the pavers
and proposed storm drain system where it will be treated for water quality and detention
via an oversized pervious paver system before being released into the Mason Street
Interceptor storm drain that ultimately conveys water into the Fossil Creek channel.
4.2 Specific Details
A summary of the drainage patterns within each basin is provided in the following
paragraphs. Please refer to Appendix A for the drainage plan.
Basin A is 0.18 acres and consists of the north drive aisle area and the proposed building.
The basin drains to the curb inlet at Design Point a that collects flow from this area and
conveys flow to the subgrade of the pervious paver detention system. Roof drains will be
directly connected to this storm system. This flow will not filter through the pavers but
rather enter the subgrade of the system by backing up in underdrains where detention will
occur.
6
Basins B is 0.50 acres and consists of the south parking area and the existing Jiffy Lube
building. Flows from this basin will be captured by the pervious paver system where the
100-year developed flow will be detained and reduced to the required 0.5 cfs per acre
(0.34 cfs).
The water quality capture volume for the entire site was sized based on a 40-hour drain
time and is 790 cf. Please refer to Appendix D for water quality information.
Based on the allowable release rate of 0.34 cfs, the required 100-year storage volume for
the site is 5,205 cf. Therefore, the total required volume with the 790 cf of water quality
is 5,995 ft. This volume will be accounted for by the combination of the pervious paver
system and 0.4 ft of parking lot detention. Detained flow will be released into the existing
inlet an existing storm system in College Avenue and ultimately to the Fossil Creek
channel. Please refer to Appendix E for detention information.
5. CONCLUSIONS
5.1 Compliance with Standards
All computations that have been completed within this report are in compliance with the
City of Fort Collins Storm Drainage Design Criteria Manual.
5.2 Drainage Concept
The proposed drainage concepts presented in this report and on the construction plans
adequately provides for stormwater quantity and quality treatment of proposed
impervious areas. Conveyance elements have been designed to pass required flows and
to minimize future maintenance.
If, at the time of construction, groundwater is encountered, a Colorado Department of
Health Construction Dewatering Permit will be required.
7
6. REFERENCES
1. City of Fort Collins, “Fort Collins Stormwater Criteria Manual”, adopted
December 2018.
2. Urban Drainage and Flood Control District, “Urban Storm Drainage Criteria
Manual”, Volumes 1 and 2, updated January 2016, and Volume 3 updated
November 2010.
3. Stewart and Associates, Inc., “Final Drainage Report for Lot 1, The Gateway at
Harmony Road P.U.D., First Filing for Jiffy Lube, Inc.” dated October 13, 1993.
A
APPENDIX A
VICINITY MAP AND DRAINAGE PLAN
SITE
vicinity map
Scale:: 1"=500'
PROP
BLDG
FF=
37.30
FF=37.45
LOT 1
BLANKET
UE, DE, AE
LOT 2
BLANKET
UE, DE, AE
Revisions
No. Date Description By
Revisions
No. Date Description By
0
SCALE: 1" = 20'
20 10 20 40
1218 W. Ash, Suite A
Windsor , Colorado 80550
Phone: (970) 674-3300
Fax: (970) 674-3303
I N T E R W E S T C O N S U L T I N G G R O U P
PREPARED FOR
PROJ. NO.
DATE:
SCALE (H):
SCALE (V):
CHECKED BY:
DESIGNED BY:
PROJECT NAME
KENSINGTON COMMONS
DUTCH BROS COFFEE
DRAINAGE PLAN
4/22/2019
N/A
N/A
ES
MPO
1380-165-00
5 of 5
M SQUARED, LLC
1600 EAST MULBERRY ST., UNIT 1
FORT COLLINS, COLORADO 80525
CONTACT: NATE FRARY
PROPOSED MINOR CONTOUR
PROPOSED MAJOR CONTOUR
EXISTING MINOR CONTOUR
EXISTING MAJOR CONTOUR
LEGEND
PROPOSED DIRECTION OF OVERLAND FLOW
MINOR STORM RUNOFF COEFFICIENT
DRAINAGE BASIN AREA, ACRES
PROPOSED DRAINAGE BASIN ID
DESIGN POINT
PROPOSED DRAINAGE
BASIN DIVIDE LINE
B
APPENDIX B
HYDROLOGIC COMPUTATIONS
Interwest Consulting Group
DRAINAGE SUMMARY TABLE
Design Tributary Area C (10) C (100) tc (10) tc (100) Q(10)tot Q(100)tot
Sub-basin REMARKS
Point (ac) (min) (min) (cfs) (cfs)
a A 0.18 0.88 1.00 5.0 5.0 0.8 1.8
b B 0.50 0.67 0.83 12.8 12.0 1.1 3.0
4-15-19 COFC FLOW.xls
Interwest Consulting Group
RUNOFF COEFFICIENTS & % IMPERVIOUS
LOCATION: Dutch Bros - Kensington
PROJECT NO: 1380-165-00
COMPUTATIONS BY: es
DATE: 4/15/2019
Recommended Runoff Coefficients from Table 3.2-2 of City of Fort Collins Stormwater Criteria Manual
Recommended % Impervious from Table 4.1-3 of City of Fort Collins Stormwater Criteria Manual
Type B Soils Runoff %
coefficient Impervious
C
Streets, parking lots (asphalt): 0.95 100
Sidewalks (concrete): 0.95 100
Roofs: 0.95 90
Gravel or Pavers: 0.50 40
Landscape Areas (Avg, sandy) : 0.15 2
Landscape Areas (Steep, sandy) : 0.20 2
SUBBASIN TOTAL TOTAL ROOF PAVED PAVERS SIDEWALK LANDSCAPE RUNOFF %
DESIGNATION AREA AREA AREA AREA AREA AREA AREA COEFF. Impervious REMARKS
(ac.) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (C)
EX 0.67 29,402 2,891 18,047 0 2,918 5,545 0.81 81
A 0.18 7,692 1,034 4,529 0 1,427 701 0.88 90
B 0.50 21,710 2,085 6,698 5,939 2,308 4,680 0.67 61 Pervious Pavers
TOTAL 0.67 29,402 3,119 11,227 5,939 3,736 5,382 0.72 69
NOTE: BASIN B EXISTING IMPERVIOUS AREA = 4582 SF
Equations
- Calculated C coefficients & % Impervious are area weighted
C = Σ (Ci Ai) / At
Ci = runoff coefficient for specific area, Ai
Ai = areas of surface with runoff coefficient of Ci
n = number of different surfaces to consider
At = total area over which C is applicable; the sum of all Ai's
4-15-19 COFC FLOW.xls
Interwest Consulting Group
STANDARD FORM SF-2
TIME OF CONCENTRATION - 2 and 10 YR
LOCATION: Dutch Bros - Kensington
PROJECT NO: 1380-165-00
COMPUTATIONS BY: es
DATE: 4/15/2019
2 and 10-yr storm Cf = 1.00 from Table RO-12 of City of Fort Collins Stormwater Code, Volume I
SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS
DATA TIME (ti) (tt) (URBANIZED BASIN) tc
DESIGN SUBBASIN(s) Area C Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10
PONIT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min)
(1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14)
a A 0.18 0.88 10 2.0 1.0 190 2.0 0.012 3.8 0.8 1.9 200 11.1 5.0
b B 0.50 0.67 10 2.0 2.0 1220 0.5 0.012 1.9 10.7 12.8 1230 16.8 12.8
EQUATIONS:
tc = ti + tt
ti = [1.87 (1.1 - CCf ) L0.5 ] / S 1/3
tt = L/Vel.
Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual)
final tc = minimum of ti + tt and urbanized basin check
min. tc = 5 min. due to limits of IDF curves
4-15-19 COFC FLOW.xls
Interwest Consulting Group
STANDARD FORM SF-2
TIME OF CONCENTRATION - 100 YR
LOCATION: Dutch Bros - Kensington
PROJECT NO: 1380-165-00
COMPUTATIONS BY: es
DATE: 4/15/2019
100-yr storm Cf = 1.25 from Table RO-12 of City of Fort Collins Stormwater Code, Volume I
SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS
DATA TIME (ti) (tt) (URBANIZED BASIN) tc
DESIGN SUBBASIN(s) Area C C*Cf Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10
PONIT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min)
(1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14)
a A 0.18 0.88 1.00 10 2.0 0.5 190 2.0 0.012 3.8 0.8 1.3 200 11.1 5.0
b B 0.50 0.67 0.83 10 2.0 1.3 1220 0.5 0.012 1.9 10.7 12.0 1230 16.8 12.0
EQUATIONS:
tc = ti + tt
ti = [1.87 (1.1 - CCf ) L0.5 ] / S 1/3
tt = L/Vel.
Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual)
final tc = minimum of ti + tt and urbanized basin check
min. tc = 5 min. due to limits of IDF curves
4-15-19 COFC FLOW.xls
Interwest Consulting Group
RATIONAL METHOD PEAK RUNOFF
(City of Fort Collins, 10-Yr Storm)
LOCATION: Dutch Bros - Kensington
PROJECT NO: 1380-165-00
COMPUTATIONS BY: es
DATE: 4/15/2019
10 yr storm, Cf = 1.00
DIRECT RUNOFF CARRY OVER TOTAL REMARKS
Design Tributary A C Cf tc i Q (10) from Q (10) Q(10)tot
Sub-basin Design
Point (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
a A 0.18 0.88 5.0 4.87 0.8 0.8
b B 0.50 0.67 12.8 3.43 1.1 1.1
Q = Cf
C
iA
Q = peak discharge (cfs)
C = runoff coefficient
Cf
= frequency adjustment factor
i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99)
A = drainage area (acres) i = 41.44 / (10+ tc)0.7974
4-15-19 COFC FLOW.xls
Interwest Consulting Group
RATIONAL METHOD PEAK RUNOFF
(City of Fort Collins, 100-Yr Storm)
LOCATION: Dutch Bros - Kensington
PROJECT NO: 1380-165-00
COMPUTATIONS BY: es
DATE: 4/15/2019
100 yr storm, Cf = 1.25
DIRECT RUNOFF CARRY OVER TOTAL REMARKS
Des. Area A C Cf tc i Q (100) from Q (100) Q(100)tot
Design
Point Design. (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
a A 0.18 1.00 5.0 9.95 1.8 1.8
b B 0.50 0.83 12.0 7.20 3.0 3.0
Q = C iA
Q = peak discharge (cfs)
C = runoff coefficient
i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99)
A = drainage area (acres) i = 84.682 / (10+ tc)
0.7975
4-15-19 COFC FLOW.xls
City of Fort Collins Stormwater Criteria Manual
C
APPENDIX C
HYDRAULIC CALCULATIONS
(PROVIDED AT FINAL)
D
APPENDIX D
WATER QUALITY AND
LID INFORMATION
Project Name: Dutch Bros Coffee - Kensington
Project Number: 1380-165-00
Company: INTERWEST CONSULTING GROUP
Designer: ES
Date: 4/16/2019
1. Basin Storage Volume
A) Tributary Area's Imperviousness Ratio (i=Ia/100) Ia = 69 %
i = 0.69
B) Contributing Watershed Area (Area) A = 0.67 acres
C) Water Quality Capture Volume (WQCV) WQCV = 0.270584 watershed inches
(WQCV = 1.0 * (0.91 * i3 - 1.19 * i2 + 0.78i) )
D) Design Volume: Vol = WQCV/12 * Area * 1.2 Vol. = 0.018 ac-ft 789.7054 cf
Impervious Area 24,021 sf
Required Minimum Impervious Area to be Treated 12,011 sf
Treatment - Pervious Pavers 5,939 sf
Treatment - Impervious Area Treated (Basin B) 17,030 sf
Treatment - Run-on Ratio (3:1 Max) 1.9
Total Area Treated 17,030 sf
Actual % of Impervious Area On-Site Treated by LID 71 %
Pavement Area 20,902 sf
Required Minimum Area of Pervious Pavement 5,225 sf
Area of Pervious Pavers Provided 5,939 sf
Actual % of Pervious Pavement Provided 28 %
50% On-Site Treatment by LID Requirement
LID Table
25% Porous Pavement Requirement
E
APPENDIX E
DETENTION INFORMATION
Interwest Consulting Group
DETENTION VOLUME CALCULATIONS
Rational Volumetric (FAA) Method
100-Year Event
LOCATION: Dutch Bros. Kensington
PROJECT NO: 1380-165-00
COMPUTATIONS BY: es
DATE: 4/16/2019
Equations: Area trib. to pond = 0.67 acre
Developed flow = QD
= CIA C (100) = 0.90
Vol. In = Vi = T C I A = T QD
Developed C A = 0.6 acre
Vol. Out = Vo =K QPO
T Release rate, QPO
= 0.34 cfs
storage = S = Vi - Vo K = 1 (from fig 2.1)
Rainfall intensity from City of Fort Collins IDF Curve with updated (3.67") rainfall
Storm Rainfall QD
Vol. In Vol. Out Storage Storage
Duration, T Intensity, I (cfs) Vi Vo S S
(min) (in/hr) (ft
3
) (ft
3
) (ft
3
) (ac-ft)
5 9.95 6.0 1800 101 1699 0.04
10 7.77 4.7 2810 201 2609 0.06
20 5.62 3.4 4067 402 3665 0.08
30 4.47 2.7 4850 603 4247 0.10
40 3.74 2.3 5412 804 4608 0.11
50 3.23 1.9 5850 1005 4845 0.11
60 2.86 1.7 6208 1206 5002 0.11
70 2.57 1.6 6511 1407 5104 0.12
80 2.34 1.4 6774 1608 5166 0.12
90 2.15 1.3 7007 1809 5198 0.12
100 1.99 1.2 7215 2010 5205 0.12
110 1.86 1.1 7405 2211 5194 0.12
120 1.75 1.1 7578 2412 5166 0.12
Required Storage Volume: 5205 ft
3
WQCV: 789.71 ft
3
0.119 acre-ft 0.018 acre-ft
4-16-19 Detention.xls,FAA-100yr
EXISTING Detention Pond - Stage/Storage - Surface Water
LOCATION: Dutch Bros. Kensington
PROJECT NO: 1380-165-00
COMPUTATIONS BY: mpo
SUBMITTED BY: INTERWEST CONSULTING GROUP
DATE: 3/22/2017
V = 1/3 d ( A + B + sqrt(A*B))
where V = volume between contours, ft3
d = depth between contours, ft
A = surface area of contour
Required Detention Volume= 5205 cf
WQCV= 790 cf
Total Volume= 5995 cf
VOLUME IN PAVERS PARKING LOT DETENTION
Surface Incremental VOID (30%) Total Surface Incremental Total Combined
Stage Area Storage Storage Storage Stage Area Storage Storage Storage
(ft) (ft2) (ac-ft) (ac-ft) (ac-ft) (ft) (ft2) (ac-ft) (ac-ft) (ac-ft)
32.0 0
32.2 1600 107 32 32
32.4 3600 507 152 184
32.6 4900 847 254 438
32.8 5050 995 298 736
33.0 5050 1010 303 1039
33.2 5050 1010 303 1342
33.4 5050 1010 303 1645
33.6 5050 1010 303 1948
33.8 5050 1010 303 2251
34.0 5050 1010 303 2554
34.2 5050 1010 303 2857
34.4 5050 1010 303 3160
34.6 5050 1010 303 3463
34.8 5050 1010 303 3766
35.0 5050 1010 303 4069
35.2 5050 1010 303 4372
35.4 5050 1010 303 4675
35.6 5250 1030 309 4984
100-yr 35.8 5250 1050 315 5299 35.8 0
35.9 5210 523 157 5456 35.9 40 1 1 5458
36.0 5070 514 154 5611 36.0 180 10 11 5622
36.1 4810 494 148 5759 36.1 440 30 42 5800
Total 36.2 4550 468 140 5899 36.2 700 56 98 5997
Spill Over Curb 36.6
4-16-19 Detention.xls
F
APPENDIX F
SOILS INFO AND
REFERENCE MATERIALS
Hydrologic Soil Group—Larimer County Area, Colorado
(Dutch Bros. Kensington)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
4/3/2019
Page 1 of 4
4485980 4485990 4486000 4486010 4486020 4486030 4486040
4485980 4485990 4486000 4486010 4486020 4486030 4486040
493360 493370 493380 493390 493400 493410 493420 493430 493440 493450 493460 493470
493360 493370 493380 493390 493400 493410 493420 493430 493440 493450 493460 493470
40° 31' 30'' N
105° 4' 42'' W
40° 31' 30'' N
105° 4' 37'' W
40° 31' 28'' N
105° 4' 42'' W
40° 31' 28'' N
105° 4' 37'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 25 50 100 150
Feet
0 5 10 20 30
Meters
Map Scale: 1:515 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
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:
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
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
4 Altvan-Satanta loams, 3
to 9 percent slopes
B 0.9 84.7%
74 Nunn clay loam, 1 to 3
percent slopes
C 0.2 15.3%
Totals for Area of Interest 1.1 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Hydrologic Soil Group—Larimer County Area, Colorado Dutch Bros. Kensington
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
4/3/2019
Page 3 of 4
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Larimer County Area, Colorado Dutch Bros. Kensington
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
4/3/2019
Page 4 of 4
USGS The National Map: Orthoimagery. Data refreshed October, 2017.
National Flood Hazard Layer FIRMette
0 250 500 1,000 1,500 2,000 Feet
Ü
105°4'55.92"W
40°31'38.66"N
105°4'18.47"W
40°31'11.31"N
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
HAZARD SPECIAL AREAS FLOOD
Without Zone A, V, Base A99 Flood Elevation (BFE)
With BFE or Depth Zone AE, AO, AH, VE, AR
Regulatory Floodway
0.of 2% 1% Annual annual Chance chance Flood flood with Hazard, average Areas
depth areasdrainage of less less than than one one foot square or with mile
Zone X
Future ChanceAnnual Conditions Flood Hazard 1%
Zone X
Area Levee.to with See Reduced Notes. Flood Risk due
Zone X
Area with Flood Risk due to LeveeZone D
NO SCREEN Area of Minimal Flood Hazard Zone X
Area of Undetermined Flood Hazard Zone D
Channel, Culvert, or Storm Sewer
Levee, Dike, or Floodwall
Cross Sections with 1% Annual Chance
17.5 Water Surface Elevation
Coastal Transect
Coastal Transect Baseline
Profile Baseline
Hydrographic Feature
Base Flood Elevation Line (BFE)
Effective LOMRs
Limit of Study
Jurisdiction Boundary
Digital Data Available
No Digital Data Available
Unmapped
This digital map flood complies maps if with it is FEMA's not void standards as described for the below. use of
The accuracy basemap standards shown complies with FEMA's basemap
The authoritative flood hazard NFHL information web services is derived provided directly by FEMA. from This the map
was reflectnot exported changes on or 4/amendments 3/2019 at 2:50:subsequent 46 PM and to this does date and
time. becomeor The superseded NFHL and effective by new data information over time. may change
This elementsmap map image do not is appear: void if basemap the one or imagery, more of flood the following zone labels,
legend, FIRM panel scale number, bar, map and creation FIRM effective date, community date. Map identifiers,images for
unmapped regulatoryfor purposes. and unmodernized areas cannot be used
Legend
OTHER FLOOD AREAS HAZARD OF
OTHER AREAS
STRGUECNTUERREASL
FEATURES OTHER
MAP PANELS
8
1:6,000
B 20.2
The point pin selected displayed by the on the user map and is does an approximate not represent
an authoritative property location.
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 13, Sep 10, 2018
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Sep 20, 2015—Oct
21, 2017
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.
Hydrologic Soil Group—Larimer County Area, Colorado
(Dutch Bros. Kensington)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
4/3/2019
Page 2 of 4