HomeMy WebLinkAboutTHE FLATS AT HANSEN FARM - PDP220004 - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORT
PRELIMINARY DRAINAGE REPORT
THE FLATS AT HANSEN FARM
FORT COLLINS, COLORADO
JUNE 28, 2022
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COVER SHEET
June 28, 2022
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, CO 80521
RE: PRELIMINARY DRAINAGE REPORT FOR
THE FLATS AT HANSEN FARM
Dear Staff,
Northern Engineering is pleased to submit this Preliminary Drainage Report for your review. This
report accompanies the Preliminary Development Plan submittal for the proposed The Flats at
Hansen Farm.
This report has been prepared in accordance with the Fort Collins Stormwater Criteria Manual
(FCSCM) and serves to document the stormwater impacts associated with the proposed The Flats at
Hansen Farm project. We understand that review by the City of Fort Collins is to assure general
compliance with standardized criteria contained in the FCSCM.
If you should have any questions as you review this report, please feel free to contact us.
Sincerely,
NORTHERN ENGINEERING SERVICES, INC.
CASSANDRA UNGERMAN, EI DANNY WEBER, PE
Project Engineer Project Manager
Compliance Statement
I hereby attest that this report for the Preliminary drainage design for The Flats at Hansen Farm was
prepared by me or under my direct supervision, in accordance with the provisions of the Fort Collins
Stormwater Criteria Manual. I understand that the City of Fort Collins does not and will not assume
liability for drainage facilities designed by others.
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TABLE OF CONTENTS
TABLE OF CONTENTS
I. GENERAL LOCATION AND DESCRIPTION ....................................................................................... 4
II. DRAINAGE BASINS AND SUB-BASINS ............................................................................................ 6
III. DRAINAGE DESIGN CRITERIA ....................................................................................................... 6
IV. DRAINAGE FACILITY DESIGN ....................................................................................................... 8
V. CONCLUSIONS......................................................................................................................... 10
VI. REFERENCES ........................................................................................................................... 11
TABLES AND FIGURES
Figure 1 - Vicinity Map ................................................................................................................................ 4
Figure 2 - Aerial Photograph ..................................................................................................................... 5
Figure 3 - Existing Floodplains .................................................................................................................. 5
Table 1 - LID Summary ............................................................................................................................... 8
Table 2 - Detention Summary ................................................................................................................... 9
APPENDICES
APPENDIX A – HYDROLOGIC COMPUTATIONS
APPENDIX B – HYDRAULIC COMPUTATIONS
APPENDIX C – LID EXHIBIT
APPENDIX D – USDA SOILS REPORT
MAP POCKET
DR1 – DRAINAGE EXHIBIT
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I. GENERAL LOCATION AND DESCRIPTION
A. LOCATION
1. Vicinity Map
Figure 1 - Vicinity Map
2. The Flats at Hansen Farm project site is located in the northeast quarter of Section 7, Township 6
North, Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of
Colorado.
3. The project site (refer to Figure 1) is bordered to the north by Twisted Root Drive and single-family
residential; to the east by South Timberline Road; to the south by Zephyr Road and a future park
tract, and the west by an existing detention facility.
4. There is existing storm drainage infrastructure as part of the Hansen Farm subdivision supporting
these Tracts for development.
B. DESCRIPTION OF PROPERTY
1. The Flats at Hansen Farm is comprised 10.4 acres.
2. The site is currently undeveloped tracts that were graded in consideration with the design of the
adjacent Hansen Farm subdivision.
3. The project site resides in the City of Fort Collins Fossil Creek Master Drainage Basin. The detention
requirements of the subject area were considered in the design of the detention ponds for the
Hansen Farm subdivision and have been factored into the LID requirements for The Flats at Hansen
Farm, which are described in further detail throughout this report.
4. The existing groundcover consists of short grasses over designed grades and detention ponds
installed for the drainage infrastructure of the Hansen Farm subdivision. The existing on-site runoff
generally drains from the Northwest to the Southeast across flat grades (e.g., 0.50% - 2.00%) to
South Timberline Road.
5. According to the United States Department of Agriculture (USDA) Natural Resources Conservation
Service (NRCS) Soil Survey website: (http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx),
the site consists primarily of Nunn clay loam (Hydrologic Soil Group C) and Caruso Clay loam
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(Hydrological Soil Group D).
Figure 2 - Aerial Photograph
6. The Mail Creek Ditch and Williamson Ditch Lateral are significant irrigation channels located to the
North and Southwest of the project site respectively, but not directly adjacent to the site.
7. The proposed development will consist of eight (8) multi-family residential buildings containing
255 units with onsite and street parking, a community pool, and amenity areas.
8. The proposed land use is mixed
C. FLOODPLAIN
1. No portions of the site are located in a FEMA regulatory floodplain, according to the Hansen Overall
Development Plan.
Figure 3 - Existing Floodplains
2. There are no special floodplain considerations required regarding finished floor elevations of
building footprints.
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3. No floodplain use permit will be required for this project.
4. A 50’ natural habitat buffer along the Mail Creek Ditch and the irrigation lateral to the south exists
on the site. All drainage improvements will be located outside this 50’ natural habitat buffer.
II. DRAINAGE BASINS AND SUB-BASINS
A. Major Basin Description
The project area of The Flats at Hansen Farm is located within the City of Fort Collins Fossil Creek
Master Drainage Basin. Detention requirements for this basin are to detain the difference between
the 100-yr developed inflow rate and the historic 2-year release rate. However, outflow from this
property is limited by an existing outfall ditch, located on the southern property line of The Timbers
subdivision, to The Timbers.
B. Sub-Basin Description
1. The outfall for the project site is South Timberline Road along the East edge, which eventually
conveys runoff to Fossil Creek Reservoir, approximately ¼ mile to the south.
2. The existing subject site can be defined with 8 distinct drainage basins (see DR1 in the provided
map pocket).
3. The existing site runoff generally drains from Northwest to Southeast onto South Timberline Road.
4. The project area receives no offsite runoff as a deliberate design aspect of the Overall Hansen
Development Plan.
III. DRAINAGE DESIGN CRITERIA
A. OPTIONAL PROVISIONS
There are no optional provisions outside of the FCSCM proposed with The Flats at Hansen Farm.
B. STORMWATER MANAGEMENT STRATEGY
The overall stormwater management strategy employed with The Flats at Hansen Farm utilizes the
“Four Step Process” to minimize adverse impacts of urbanization on receiving waters. The following
is a description of how the proposed development has incorporated each step.
Step 1 – Employ Runoff Reduction Practices. The first consideration taken in trying to reduce the
stormwater impacts of this development is the site selection itself. By choosing an already
developed site with public storm sewer currently in place, the burden is significantly less than
developing a vacant parcel absent of any infrastructure.
The Flats at Hansen Farm aims to reduce runoff peaks, volumes and pollutant loads from
frequently occurring storm events (i.e., water quality (i.e., 80th percentile) and 2-year storm events)
by implementing Low Impact Development (LID) strategies. Wherever practical, runoff will be
routed across landscaped areas or through a rain garden or water quality pond. These LID practices
reduce the overall amount of impervious area, while at the same time Minimizing Directly
Connected Impervious Areas (MDCIA). The combined LID/MDCIA techniques will be implemented,
where practical, throughout the development, thereby slowing runoff and increasing opportunities
for infiltration.
Step 2 – Implement BMPs that Provide a Water Quality Capture Volume (WQCV) with Slow
Release. The efforts taken in Step 1 will help to minimize excess runoff from frequently occurring
storm events; however, urban development of this intensity will still have stormwater runoff
leaving the site. The primary water quality treatment will occur between several rain gardens
between major parking areas of the property and the existing detention ponds installed for the
Hansen Farm Subdivision.
Step 3 – Stabilize Drainageways. While not directly applicable to this site, the project will pay
one-time stormwater development fees as well as ongoing monthly stormwater utility fees, both of
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which help achieve citywide drainageway stability.
Step 4 – Implement Site Specific and Other Source Control BMPs. This step typically applies to
industrial and commercial developments.
C. DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS
1. The subject property is part of the Hansen Overall Development Plan (ODP).
2. The project area is constrained on all sides by public streets, with the exception of the south edge
and the west half of the north edge, which are constrained by existing single-family lots.
D. HYDROLOGICAL CRITERIA
1. The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in Figure 3.4-1 of
the FCSCM, serve as the source for all hydrologic computations associated with The Flats at Hansen
Farm development. Tabulated data contained in Table 3.4-1 has been utilized for Rational Method
runoff calculations.
2. The Rational Method has been used to estimate peak developed stormwater runoff from drainage
basins within the developed site for the 2-year, 10-year, and 100-year design storms. Peak runoff
discharges determined using this methodology have been used to check the street capacities,
inlets, swales, and storm drain lines.
3. Two separate design storms have been utilized to address distinct drainage scenarios. The first
event analyzed is the “Minor,” or “Initial” Storm, which has a 2-year recurrence interval. The second
event considered is the “Major Storm,” which has a 100-year recurrence interval.
E. HYDRAULIC CRITERIA
1. The drainage facilities proposed with The Flats at Hansen Farm project are designed in accordance
with criteria outlined in the FCSCM.
2. As stated in Section I.C.1, above, the subject property is not located next to a FEMA designated
floodplain, nor is it located within any identified floodplain limits.
F. FLOODPLAIN REGULATIONS COMPLIANCE
As previously mentioned, this project is not adjacent to a FEMA regulated floodplain and as such, it
will not be subject to any floodplain regulations.
G. MODIFICATIONS OF CRITERIA
There are no formal modifications outside of the FCSCM proposed with The Flats at Hansen Farm.
H. CONFORMANCE WITH WATER QUALITY TREATMENT CRITERIA
City Code requires that 75% of runoff from impervious surfaces in a project site shall receive some
sort of water quality treatment, of which a majority of the site is receiving. There are several small
areas that flow directly offsite, without treatment. While these small areas will not receive formal
water quality treatment, most areas will still see some treatment as runoff is directed through the
landscaped areas or across the landscaped parkways before reaching the roadway curb and gutter.
I. CONFORMANCE WITH LOW IMPACT DEVELOPMENT (LID)
The project site will conform with the requirement to treat a minimum of 75% of the project site
using a LID technique. The proposed project site will treat 88% of the site with LID, with small
portions of the site flowing directly offsite. 5 rain gardens will be used to capture and treat most of
the impervious area on the project site.
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J. SIZING OF LID & WQ FACILITIES
Rain Gardens/Underground Chambers
1. The rain gardens were sized by first determining the required water quality capture volume (WQCV)
for Sub-basins A, B, C, D, and E for the rain gardens. A 12-hour drain time was used in this
calculation.
2. Once the WQCV was identified, each rain garden area was sized for its respective WQCV. The rain
gardens will be constructed with a biomedia filter and underdrain. An overflow drain will be
provided in each rain garden and weir for chambers to pass storms greater than the WQCV.
Table 1 - LID Summary
LID ID Area (ft2) Weighted %
Impervious
Volume per
UD-BMP (ft3)
Vol. w/ 20%
increase per
FC Manual
(ft3)
Impervious
area (ft2)
Rain Garden A 56,589 70% 1,094 1,313 41,782
Rain Garden B 41,501 55% 610 732 22,736
Rain Garden C 77,741 60% 1,224 1,469 46,645
Rain Garden D 44,789 85% 1,081 1,297 37,932
Rain Garden E 119,106 77% 2,465 2,958 91,716
IV. DRAINAGE FACILITY DESIGN
A. GENERAL CONCEPT
1. The main objective of The Flats at Hansen Farm drainage design is to maintain existing drainage
patterns, while not adversely impacting adjacent properties.
2. All storm drains on the site have been designed to convey 100-yr flows.
3. A list of tables and figures used within this report can be found in the Table of Contents at the front
of the document. The tables and figures are located within the sections to which the content best
applies.
4. Drainage for the project site has been a0nalyzed using 14 onsite drainage sub- basins, designated
as sub-basins A-E and O1-O7. Sub-basins O1-O4 do not go to onsite rain gardens or detention
ponds. Sub-basins A, B, B1, C, C1, and O1 make up the west side while sub-basins D, D1, E, E1, E2
O2-O4 make up the east side. The Sub-basins are discussed in further detail below.
Sub-Basin A
Sub-basin A is comprised of multi-family residential, asphalt drives and parking, and landscaped
areas. Rain Garden A is located in Sub-Basin A and serves as the sole method of treating this basin
for LID. The flows from this basin travel via overland flow, curb and gutter, and storm pipe to Rain
Garden A. From Rain Garden A, flows are discharged into existing Detention Pond 1, proposed with
Hansen Farm.
Sub-Basins B & B1
Sub-Basins B and B1 is composed of multi-family residential, asphalt drives and parking, and small
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landscaped areas. Sub-Basin B also contains Rain Garden B, which serves to treat the sub-basin for
LID. Flows travel via overland flow, and curb and gutter to Rain Garden B, before being discharged
into existing Detention Pond 1.
Sub-Basins C & C1
Sub-Basins C & C1 contains asphalt drives and parking and small portions of multi-family
residential as well as the clubhouse, pool, and Rain Garden C. Rain Garden C will treat Sub-Basins C
and C1 for LID. Flows from these sub-basins travel via overland flow, curb and gutter, and storm
pipe to Rain Garden C. Rain Garden C then discharges though storm pipes to the east where it
ultimately goes to Detention Pond 3.
Sub-Basins D, D1, & D2
Sub-Basins D, D1, & D2 are comprised of multi-family residential, asphalt drives and parking, and
landscaped areas. Sub-Basin D contains Detention Pond 3 and Rain Garden D. Detention Pond 3
was previously proposed with Hansen Farm but is being modified to better suit the needs of the
proposed site. Rain Garden D will treat the entirety of Sub-Basins D1 and D2 for LID. Sub-Basin D
will not be treated for LID.
Sub-Basins E, E1, & E2
Sub-Basins E, E1 & E2 are composed of multi-family residential, asphalt drives and parking, and
landscaped areas. Sub-Basin E also contains Rain Garden E, which treats sub-basins E, E1, and E2
for LID.
Sub-Basins O1-O4
Sub-Basins O1-O4 are not treated for LID and flow directly offsite. Sub-Basin O1 flows via overland
flow to existing Detention Pond 1. Sub-Basin O2 flows via overland flow onto Burly Tree Drive
where it is directed north to an existing inlet and storm pipe that carry these flows to existing
Detention Pond 2. Sub-Basin O3 flows via overland flow to Twisted Root where it is picked up by an
existing inlet and is then routed north to an existing inlet and storm pipe that route flows to existing
Detention Pond 2. Sub-Basin O4 flows directly onto Twisted Root Drive where existing inlets and
storm take these flows to existing Detention Pond 2.
A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report.
B. SPECIFIC DETAILS
1. There are no new detention ponds being proposed with this development. Previously constructed
ponds will detain up to the 100-yr storm event and release at or below the calculated release rate.
Detention Pond 3 will capture a large portion of the site runoff, as was previously planned.
Considering the percent impervious values are less than what was assumed for this area, Detention
Pond 3 should be adequate to capture and treat the runoff going to it. Modifications, however, were
made to this pond in order to lessen the impact that earthwork had on the rest of the site. A SWMM
model was created with the previous Hansen Farm submittal to determine the detention volumes.
See Table 2 for detention summary.
Table 2 - Detention Summary
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2. LID treatment is being provided within Rain Gardens A-E. These treat approximately 88% of the site
impervious runoff, which is more than the required 75% LID treatment. Please see the LID exhibit
and calculations in Appendix C.
3. Detention allowable release rate is based on computed 2-year historic flow for the overall property
as proposed with the Hansen Farm development plan.
4. Stormwater facility Standard Operations Procedures (SOP) will be provided by the City of Fort
Collins in the Development Agreement.
5. Preliminary Design details, and construction documentation shall be provided to the City of Fort
Collins for review prior to Preliminary Development Plan approval.
V. CONCLUSIONS
A. COMPLIANCE WITH STANDARDS
1. The drainage design proposed with The Flats at Hansen Farm complies with the City of Fort Collins
Master Drainage Plan for the Spring Creek and Canal Importation Basins.
2. The drainage plan and stormwater management measures proposed with The Flats at Hansen
Farm project are compliant with all applicable State and Federal regulations governing stormwater
discharge.
B. DRAINAGE CONCEPT
1. The drainage plan and stormwater management measures proposed with The Flats at Hansen
Farm project are compliant with all applicable State and Federal regulations governing stormwater
discharge.
2. The Flats at Hansen Farm will not impact the Master Drainage Plan recommendations for the City of
Fort Collins Fossil Creek Major Drainage Basin.
3. The proposed drainage plan for the Flats at Hansen Farm complies with the previously proposed
impervious values for the site from the Hansen Farm plan dated August 26, 2020. For this reason, it
is believed the previous infrastructure constructed with Hansen Farm will continue to be sufficient
as this portion of the site is developed. Th impervious values for the newly developed site are less
than what was anticipated with the Hansen Farm proposal.
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VI. REFERENCES
1. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance
No. 159, 2018, and referenced in Section 26-500 of the City of Fort Collins Municipal Code.
2. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service,
United States Department of Agriculture.
3. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District,
Wright- McLaughlin Engineers, Denver, Colorado, Revised April 2008.
4. Final Drainage and Erosion Control Report for Hansen Farm, Northern Engineering, Fort Collins,
Colorado, dated August 26, 2020.
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APPENDIX
APPENDIX A
HYDROLOGIC COMPUTATIONS
CHARACTER OF SURFACE1:
Percentage
Impervious
2-yr Runoff
Coefficient
10-yr Runoff
Coefficient
100-yr Runoff
Coefficient
Developed
Asphalt .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100%0.95 0.95 1.00
Concrete .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………90%0.95 0.95 1.00
Rooftop .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………90%0.95 0.95 1.00
Gravel .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40%0.50 0.50 0.63
Pavers .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………40%0.50 0.50 0.63
Landscape or Pervious Surface
Playgrounds .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………25%0.35 0.35 0.44
Lawns Clayey Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………0%0.25 0.25 0.31
Lawns Sandy Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………0%0.15 0.15 0.19
Notes:
Basin ID Basin Area
(ac)
Area of
Asphalt/Con
crete
(ac)
Area of
Concrete
(ac)
Area of
Rooftop
(ac)
Area of
Gravel
(ac)
Area of
Pavers
(ac)
Area of
Playgrounds
(ac)
Area of Lawns
(ac)
Composite
% Imperv.
2-year
Composite Runoff
Coefficient
10-year
Composite
Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
A 1.37 0.48 0.06 0.47 0.42 70% 0.78 0.78 0.83
B 0.59 0.22 0.04 0.05 0.28 51% 0.62 0.62 0.67
B1 0.36 0.00 0.00 0.25 0.11 61% 0.73 0.73 0.78
C 0.72 0.33 0.02 0.18 0.19 70% 0.76 0.76 0.81
C1 1.00 0.27 0.03 0.29 0.71 57% 0.75 0.75 0.82
D 1.27 0.00 0.06 0.11 1.10 12% 0.34 0.34 0.40
D1 0.54 0.26 0.02 0.22 0.04 88% 0.90 0.90 0.95
D2 0.49 0.29 0.02 0.10 0.08 81% 0.84 0.84 0.89
E 2.17 1.22 0.15 0.45 0.35 81% 0.84 0.84 0.89
E1 0.21 0.17 0.02 0.00 0.03 86% 0.86 0.86 0.91
E2 0.35 0.00 0.01 0.18 0.17 47% 0.62 0.62 0.67
O1 0.18 0.00 0.00 0.00 0.18 0% 0.25 0.25 0.31
O2 0.93 0.22 0.04 0.31 0.58 58% 0.74 0.74 0.81
O3 0.06 0.01 0.00 0.00 0.05 11% 0.33 0.33 0.39
O4 0.15 0.01 0.01 0.00 0.14 10% 0.33 0.33 0.39
East Side 6.17 2.17 0.32 1.37 0.00 0.00 0.00 2.53 60% 0.70 0.70 0.76
West Side 4.22 1.30 0.15 1.24 0.00 0.00 0.00 1.89 60% 0.72 0.72 0.78
Total 10.38 3.47 0.47 2.61 0.00 0.00 0.00 4.42 60% 0.71 0.71 0.76
DEVELOPED BASIN % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
2) Runoff Coefficients are taken from the Fort Collins Stormwater Criteria Manual, Chapter 3. Table 3.2-1 and 3.2-2
1) Percentage impervious taken from the Fort Collins Stormwater Criteria Manual, Chapter 5, Table 4.1-2 and Table 4.1-3
Combined Basins
Rational Method Equation:
Rainfall Intensity:
a A 1.37 5.0 5.0 0.78 0.83 2.85 4.87 9.95 3.05 5.21 11.32
b B 0.59 6.5 5.9 0.62 0.67 2.60 4.44 9.63 0.95 1.63 3.82
b1 B1 0.36 5.2 5.0 0.73 0.78 2.85 4.87 9.95 0.75 1.28 2.80
c C 0.72 6.7 6.1 0.76 0.81 2.60 4.44 9.31 1.42 2.42 5.42
c1 C1 1.00 5.0 5.0 0.75 0.82 2.85 4.87 9.95 2.13 3.64 8.14
d D 1.27 7.6 7.1 0.34 0.40 2.46 4.21 8.80 1.06 1.81 4.46
d1 D1 0.54 5.0 5.0 0.90 0.95 2.85 4.87 9.95 1.39 2.38 5.12
d2 D2 0.49 5.0 5.0 0.84 0.89 2.85 4.87 9.95 1.16 1.99 4.30
e E 2.17 5.0 5.0 0.84 0.89 2.85 4.87 9.95 5.20 8.88 19.23
e1 E1 0.21 5.0 5.0 0.86 0.91 2.85 4.87 9.95 0.52 0.88 1.91
e2 E2 0.35 5.7 5.2 0.62 0.67 2.76 4.72 9.95 0.60 1.03 2.35
o1 O1 0.18 7.5 7.0 0.25 0.31 2.46 4.21 9.06 0.11 0.19 0.50
o2 O2 0.93 5.0 5.0 0.74 0.81 2.85 4.87 9.95 1.96 3.36 7.51
o3 O3 0.06 5.0 5.0 0.33 0.39 2.85 4.87 9.95 0.05 0.09 0.22
o4 O4 0.15 5.0 5.0 0.33 0.39 2.85 4.87 9.95 0.14 0.24 0.57
6.17 12.5 12.5 0.70 0.76 2.05 2.05 7.16 8.85 8.85 33.55
4.22 12.5 12.5 0.72 0.78 2.02 2.02 7.04 6.12 6.12 23.15
Combined Basins
West Side
East Side
DEVELOPED RUNOFF COMPUTATIONS
Design
Point Basin(s)Area, A
(acres)
Tc2
(min)
Flow,
Q2
(cfs)
Flow,
Q100
(cfs)
C2 C100
IDF Table for Rational Method - Table 3.4-1 FCSCM
Intensity,
i10
(in/hr)
Flow,
Q10
(cfs)
Tc100
(min)
Intensity,
i2
(in/hr)
Intensity,
i100
(in/hr)
()()()AiCCQf=
Overland Flow, Time of Concentration:
Channelized Flow, Time of Concentration:
Total Time of Concentration :
T c is the lesser of the values of Tc calculated using T c = T i + T t
C2 C100
Length,
L
(ft)
Slope,
S
(%)
Ti2 Ti100
Length,
L
(ft)
Slope,
S
(%)
Roughness
Coefficient
Assumed
Hydraulic
Radius
Velocity,
V
(ft/s)
Tt
(min)Tc (Eq. 3.3-5) Tc2 = Ti +Tt Tc100 = Ti +Tt Tc2 Tc100
a A 0.78 0.83 43 2.33%3.0 2.5 407 1.15%0.015 0.59 7.50 0.9 12.5 3.9 3.4 5.0 5.0
b B 0.62 0.67 58 1.59%5.9 5.3 313 1.30%0.015 0.59 7.97 0.7 12.1 6.5 5.9 6.5 5.9
b1 B1 0.73 0.78 58 1.59%4.5 3.9 313 1.30%0.015 0.59 7.97 0.7 12.1 5.2 4.6 5.2 5.0
c C 0.76 0.81 66 2.03%4.1 3.5 336 0.10%0.015 0.59 2.16 2.6 12.2 6.7 6.1 6.7 6.1
c1 C1 0.75 0.82 50 3.30%3.1 2.5 N/A 0.015 0.59 N/A N/A 10.3 3.1 2.5 5.0 5.0
d D 0.34 0.40 81 7.31%6.6 6.1 362 0.76%0.015 0.59 6.10 1.0 12.5 7.6 7.1 7.6 7.1
d1 D1 0.90 0.95 36 2.08%1.8 1.3 270 0.41%0.015 0.59 4.50 1.0 11.7 2.8 2.3 5.0 5.0
d2 D2 0.84 0.89 31 2.48%2.0 1.6 202 0.69%0.015 0.59 5.80 0.6 11.3 2.6 2.2 5.0 5.0
e E 0.84 0.89 36 2.08%2.3 1.8 270 0.41%0.015 0.59 4.50 1.0 11.7 3.3 2.8 5.0 5.0
e1 E1 0.86 0.91 45 2.49%2.2 1.8 60 1.41%0.015 0.59 8.30 0.1 10.6 2.3 1.9 5.0 5.0
e2 E2 0.62 0.67 55 2.67%4.8 4.3 292 0.60%0.015 0.59 5.41 0.9 11.9 5.7 5.2 5.7 5.2
o1 O1 0.25 0.31 49 3.24%7.5 7.0 N/A 0.015 0.59 N/A N/A 10.3 7.5 7.0 7.5 7.0
o2 O2 0.74 0.81 64 3.75%3.5 2.8 N/A 0.015 0.59 N/A N/A 10.4 3.5 2.8 5.0 5.0
o3 O3 0.33 0.39 12 9.25%2.4 2.2 N/A 0.038 0.50 N/A N/A 10.1 2.4 2.2 5.0 5.0
o4 O4 0.33 0.39 35 5.46%4.8 4.5 N/A 0.015 n/a N/A N/A 10.2 4.8 4.5 5.0 5.0
0.70 0.76 81 7.31% 3.5 2.9 362 0.76% 3.015 0.59 0.03 198.8 12.5 202.2 201.7 12.5 12.5
0.72 0.78 43 2.33% 3.5 3.0 407 1.15% 4.015 0.59 0.03 242.1 12.5 245.6 245.0 12.5 12.5
Combined Basins
West Side
East Side
DEVELOPED DIRECT TIME OF CONCENTRATION
Channelized Flow
Design
Point Basin
Overland Flow Time of Concentration
Frequency Adjustment Factor:
(Equation 3.3-2 FCSCM)
(Equation 5-5 FCSCM)
(Equation 5-4 FCSCM)
(Equation 3.3-5 FCSCM)
Table 3.2-3 FCSCM
Therefore Tc2=Tc10 Notes:
1) Add 5000 to all elevations.
2) Per Fort Collins Stormwater Manual, minimum Tc = 5 min.
3) Assume a water depth of 6" and a typical curb and gutter per Larimer County
Urban Street Standard Detail 701 for curb and gutter channelized flow. Assume a
water depth of 1', fixed side slopes, and a triangular swale section for grass
channelized flow. Assume a water depth of 1', 4:1 side slopes, and a 2' wide valley
pan for channelized flow in a valley pan.
NORTHERNENGINEERING.COM | 970.221.4158
FORT COLLINS | GREELEY
PRELIMINARY DRAINAGE REPORT: THE FLATS AT HANSEN FARM
APPENDIX
APPENDIX B
HYDRAULIC COMPUTATIONS
Preliminary Drainage Report November 10, 2020
Watermark Residential
This section intentionally left blank.
Hydraulic calculations will be completed during final design.
NORTHERNENGINEERING.COM | 970.221.4158
FORT COLLINS | GREELEY
PRELIMINARY DRAINAGE REPORT: THE FLATS AT HANSEN FARM
APPENDIX
APPENDIX C
LID EXHIBIT
8" W
8" W 8" W FMELEC
ELEC
ELEC
ELEC
G
G G GGGGG GGGEEEEEEE / / / / / / / /SSSSSSSSSSSS
SS SS
8" W 8" WWWWWWWWWWTTTTTTT
E
EETEGGGGG
GGGG E
EEXX
C
C1
O2
E
D
D2
E2
O4
B
A
DETENTION
POND 3
RAIN
GARDEN D
RAIN
GARDEN E
RAIN
GARDEN B
RAIN
GARDEN A
RAIN
GARDEN C
EXISTING
DETENTION
POND 1
KNOBBY PINE DRIVE
ZEPHYR ROADBURLY TREE DRIVETWISTED ROOT DRIVE
SOUTH TIMBERLINE ROADA
B
C
D
E
C1
O2
B1
O3
E2
O4
O1
D1
D2
E1
B1
D1
E1
O3
O1
PROPOSED STORM SEWER
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
ADESIGN POINT
DRAINAGE BASIN LABEL
DRAINAGE BASIN BOUNDARY
A
LEGEND:
DRAWN BY:
SCALE:
ISSUED:
THE FLATS AT
HANSEN FARM
SHEET NO:
FORT COLLINS: 301 North Howes Street, Suite 100, 80521
GREELEY: 820 8th Street, 80631
E N G I N E E R N GI
EHTRON R N
970.221.4158
northernengineering.com
LID EXHIBIT
C. Ungerman
1in=120ft
6/20/22
( IN FEET )
1 inch = ft.
Feet0120120
120
RAIN GARDEN LIMITS
STORMTECH CHAMBERS
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
LID Site Summary - New Impervious Area
Total Area of Current Development 473,745 ft2
Total Impervious Area 271,882 ft2
Total Impervious Area without LID Treatment 24,449 ft2
O1-O7
75% Requried Minimum Area to be Treated 203,911
Total Treated Area 240,811 ft2
Percent Impervious Treated by LID 88.57%
Project Number:Project:
Project Location:
Calculations By:Date:
Sq. Ft. Acres
A 59,689 1.37 70%Rain Garden A Rain Garden 1,313 41,782
B 25,792 0.59 51%Rain Garden B Rain Garden 732 13,154
B1 15,709 0.36 61%Rain Garden B Rain Garden 732 9,582
C 31,301 0.72 70% Rain Garden C Rain Garden 1,468 21,911
C1 43,432 1.00 56% Rain Garden C Rain Garden 1,468 24,322
D 55,183 1.27 12% n/a n/a 0 6,622
D1 23,616 0.54 88% Rain Garden D Rain Garden 1,297 20,782
D2 21,173 0.49 81% Rain Garden D Rain Garden 1,297 17,150
E 94,586 2.17 81% Rain Garden E Rain Garden 2,958 76,615
E1 9,172 0.21 86% Rain Garden E Rain Garden 2,958 7,888
E2 15,348 0.35 47% Rain Garden E Rain Garden 2,958 7,214
O1 7,737 0.18 0% n/a n/a 0 0
O2 40,573 0.93 58% n/a n/a 0 23,532
O3 2,508 0.06 11% n/a n/a 0 276
O4 6,403 0.15 10% n/a n/a 0 640
Total 473,973 9.51 271,470
LID Summary
Project Number:Project:
Project Location:
Calculations By:Date:
LID Summary
per LID
Structure
Sq. Ft. Acres
Rain Garden A 59,689 1.37 70%A Rain Garden 1,094 1,313 41,782
Rain Garden B 41,501 0.95 55%B Rain Garden 610 732 22,736
Rain Garden C 74,733 1.72 62%C Rain Garden 1,211 1,453 46,233
Rain Garden D 44,789 1.03 85%D Rain Garden 1,081 1,297 37,932
Rain Garden E 119,106 2.73 77%E Rain Garden 2,465 2,958 91,716
Total 339,818 4.04 3,498 240,400
473,973 ft2
271,470 ft2
24,449 ft2
203,603 ft3
240,400 ft2
88.55%
LID ID Volume per
UD-BMP (ft3)
Total Treated Area
Percent Impervious Treated by LID
O1-O7
75% Requried Minimum Area to be Treated
LID Site Summary - New Impervious Area
Total Area of Current Development
Total Impervious Area
Total Impervious Area without LID Treatment
Impervious
Area (ft2)
Vol. w/20%
Increase per
Fort Collins
Manual (ft3)
The Flats at Hansen Farm
6/29/2022
Subbasin ID Treatment Type
Area
Weighted %
Impervious
1916-001
Fort Collins, Colorado
C. Ungerman
LID Summary
AreaBasin ID Treatment TypePercent
Impervious LID ID
The Flatrs at Hansen Farm
6/29/2022
1916-001
Fort Collins, Colorado
C. Ungerman
Total
Impervious
Area (ft2)
Required
Volume (ft3)
LID Summary per Basin
NORTHERNENGINEERING.COM | 970.221.4158
FORT COLLINS | GREELEY
PRELIMINARY DRAINAGE REPORT: THE FLATS AT HANSEN FARM
APPENDIX
APPENDIX D
USDA SOILS REPORT
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, ColoradoNatural
Resources
Conservation
Service
September 12, 2017
Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifying and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
2
alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or
call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity
provider and employer.
3
Contents
Preface....................................................................................................................2
How Soil Surveys Are Made..................................................................................5
Soil Map.................................................................................................................. 8
Soil Map................................................................................................................9
Legend................................................................................................................10
Map Unit Legend................................................................................................ 11
Map Unit Descriptions.........................................................................................11
Larimer County Area, Colorado......................................................................14
5—Aquepts, loamy......................................................................................14
22—Caruso clay loam, 0 to 1 percent slope............................................... 15
34—Fort Collins loam, 0 to 1 percent slopes.............................................. 16
35—Fort Collins loam, 0 to 3 percent slopes.............................................. 17
36—Fort Collins loam, 3 to 5 percent slopes.............................................. 19
37—Fort Collins loam, 5 to 9 percent slopes.............................................. 20
55—Kim loam, 5 to 9 percent slopes.......................................................... 21
63—Longmont clay, 0 to 3 percent slopes.................................................. 23
73—Nunn clay loam, 0 to 1 percent slopes.................................................24
74—Nunn clay loam, 1 to 3 percent slopes.................................................25
76—Nunn clay loam, wet, 1 to 3 percent slopes.........................................27
79—Otero sandy loam, 5 to 9 percent slopes.............................................28
Soil Information for All Uses...............................................................................30
Soil Properties and Qualities..............................................................................30
Soil Qualities and Features.............................................................................30
Hydrologic Soil Group................................................................................. 30
References............................................................................................................35
4
How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous
areas in a specific area. They include a description of the soils and miscellaneous
areas and their location on the landscape and tables that show soil properties and
limitations affecting various uses. Soil scientists observed the steepness, length,
and shape of the slopes; the general pattern of drainage; the kinds of crops and
native plants; and the kinds of bedrock. They observed and described many soil
profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The
profile extends from the surface down into the unconsolidated material in which the
soil formed or from the surface down to bedrock. The unconsolidated material is
devoid of roots and other living organisms and has not been changed by other
biological activity.
Currently, soils are mapped according to the boundaries of major land resource
areas (MLRAs). MLRAs are geographically associated land resource units that
share common characteristics related to physiography, geology, climate, water
resources, soils, biological resources, and land uses (USDA, 2006). Soil survey
areas typically consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that
is related to the geology, landforms, relief, climate, and natural vegetation of the
area. Each kind of soil and miscellaneous area is associated with a particular kind
of landform or with a segment of the landform. By observing the soils and
miscellaneous areas in the survey area and relating their position to specific
segments of the landform, a soil scientist develops a concept, or model, of how they
were formed. Thus, during mapping, this model enables the soil scientist to predict
with a considerable degree of accuracy the kind of soil or miscellaneous area at a
specific location on the landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented
by an understanding of the soil-vegetation-landscape relationship, are sufficient to
verify predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them
to identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character
of soil properties and the arrangement of horizons within the profile. After the soil
5
scientists classified and named the soils in the survey area, they compared the
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that
have similar use and management requirements. Each map unit is defined by a
unique combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components
of the map unit. The presence of minor components in a map unit in no way
diminishes the usefulness or accuracy of the data. The delineation of such
landforms and landform segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, onsite
investigation is needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape,
and experience of the soil scientist. Observations are made to test and refine the
soil-landscape model and predictions and to verify the classification of the soils at
specific locations. Once the soil-landscape model is refined, a significantly smaller
number of measurements of individual soil properties are made and recorded.
These measurements may include field measurements, such as those for color,
depth to bedrock, and texture, and laboratory measurements, such as those for
content of sand, silt, clay, salt, and other components. Properties of each soil
typically vary from one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists
interpret the data from these analyses and tests as well as the field-observed
characteristics and the soil properties to determine the expected behavior of the
soils under different uses. Interpretations for all of the soils are field tested through
observation of the soils in different uses and under different levels of management.
Some interpretations are modified to fit local conditions, and some new
interpretations are developed to meet local needs. Data are assembled from other
sources, such as research information, production records, and field experience of
specialists. For example, data on crop yields under defined levels of management
are assembled from farm records and from field or plot experiments on the same
kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on
such variables as climate and biological activity. Soil conditions are predictable over
long periods of time, but they are not predictable from year to year. For example,
soil scientists can predict with a fairly high degree of accuracy that a given soil will
have a high water table within certain depths in most years, but they cannot predict
that a high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
Custom Soil Resource Report
6
identified each as a specific map unit. Aerial photographs show trees, buildings,
fields, roads, and rivers, all of which help in locating boundaries accurately.
Custom Soil Resource Report
7
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
8
9
Custom Soil Resource Report
Soil Map
44833004483400448350044836004483700448380044839004484000448410044842004484300448440044845004483300448340044835004483600448370044838004483900448400044841004484200448430044844004484500495900 496000 496100 496200 496300 496400 496500 496600 496700
495900 496000 496100 496200 496300 496400 496500 496600 496700
40° 30' 41'' N 105° 2' 58'' W40° 30' 41'' N105° 2' 16'' W40° 29' 58'' N
105° 2' 58'' W40° 29' 58'' N
105° 2' 16'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 300 600 1200 1800
Feet
0 50 100 200 300
Meters
Map Scale: 1:6,420 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
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:
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 the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 11, Sep 23, 2016
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Mar 20, 2015—Oct
15, 2016
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
10
Map Unit Legend
Larimer County Area, Colorado (CO644)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
5 Aquepts, loamy 15.4 8.8%
22 Caruso clay loam, 0 to 1
percent slope
4.0 2.3%
34 Fort Collins loam, 0 to 1 percent
slopes
1.9 1.1%
35 Fort Collins loam, 0 to 3 percent
slopes
8.6 4.9%
36 Fort Collins loam, 3 to 5 percent
slopes
30.9 17.6%
37 Fort Collins loam, 5 to 9 percent
slopes
1.1 0.6%
55 Kim loam, 5 to 9 percent slopes 4.4 2.5%
63 Longmont clay, 0 to 3 percent
slopes
6.6 3.8%
73 Nunn clay loam, 0 to 1 percent
slopes
23.5 13.4%
74 Nunn clay loam, 1 to 3 percent
slopes
67.6 38.5%
76 Nunn clay loam, wet, 1 to 3
percent slopes
3.8 2.2%
79 Otero sandy loam, 5 to 9
percent slopes
7.7 4.4%
Totals for Area of Interest 175.6 100.0%
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.
Custom Soil Resource Report
11
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 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
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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.
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Larimer County Area, Colorado
5—Aquepts, loamy
Map Unit Setting
National map unit symbol: jpws
Elevation: 4,500 to 6,700 feet
Mean annual precipitation: 12 to 18 inches
Mean annual air temperature: 39 to 50 degrees F
Frost-free period: 80 to 140 days
Farmland classification: Not prime farmland
Map Unit Composition
Aquepts and similar soils: 80 percent
Minor components: 20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Aquepts
Setting
Landform: Depressions, draws, stream terraces
Landform position (three-dimensional): Base slope, tread, dip
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Loamy alluvium
Typical profile
H1 - 0 to 60 inches: variable
Properties and qualities
Slope: 0 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Very poorly drained
Runoff class: Negligible
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
very high (0.60 to 99.90 in/hr)
Depth to water table: About 6 to 18 inches
Frequency of flooding: Rare
Frequency of ponding: None
Interpretive groups
Land capability classification (irrigated): 5w
Land capability classification (nonirrigated): 3w
Hydrologic Soil Group: A/D
Hydric soil rating: Yes
Minor Components
Fort collins
Percent of map unit: 5 percent
Hydric soil rating: No
Nunn
Percent of map unit: 5 percent
Hydric soil rating: No
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Stoneham
Percent of map unit: 5 percent
Hydric soil rating: No
Kim
Percent of map unit: 5 percent
Hydric soil rating: No
22—Caruso clay loam, 0 to 1 percent slope
Map Unit Setting
National map unit symbol: jpvt
Elevation: 4,800 to 5,500 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
Caruso and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Caruso
Setting
Landform: Flood-plain steps, stream terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Mixed alluvium
Typical profile
H1 - 0 to 35 inches: clay loam
H2 - 35 to 44 inches: fine sandy loam, sandy loam
H2 - 35 to 44 inches: sand, gravelly sand
H3 - 44 to 60 inches:
H3 - 44 to 60 inches:
Properties and qualities
Slope: 0 to 1 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Somewhat poorly drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: About 24 to 48 inches
Frequency of flooding: Occasional
Frequency of ponding: None
Calcium carbonate, maximum in profile: 5 percent
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Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: High (about 9.8 inches)
Interpretive groups
Land capability classification (irrigated): 3w
Land capability classification (nonirrigated): 5w
Hydrologic Soil Group: D
Hydric soil rating: No
Minor Components
Loveland
Percent of map unit: 9 percent
Landform: Terraces
Hydric soil rating: Yes
Fluvaquents
Percent of map unit: 6 percent
Landform: Terraces
Hydric soil rating: Yes
34—Fort Collins loam, 0 to 1 percent slopes
Map Unit Setting
National map unit symbol: jpw7
Elevation: 4,800 to 5,500 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
Fort collins and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Fort Collins
Setting
Landform: Terraces, fans
Landform position (three-dimensional): Base slope, tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium
Typical profile
H1 - 0 to 8 inches: loam
H2 - 8 to 18 inches: loam, clay loam
H2 - 8 to 18 inches: loam, silt loam, fine sandy loam
H3 - 18 to 60 inches:
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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: 15 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: Very high (about 26.0 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability classification (nonirrigated): 3c
Hydrologic Soil Group: B
Ecological site: Loamy Plains (R067XY002CO)
Hydric soil rating: No
Minor Components
Stoneham
Percent of map unit: 6 percent
Hydric soil rating: No
Larim
Percent of map unit: 5 percent
Hydric soil rating: No
Ascalon
Percent of map unit: 4 percent
Hydric soil rating: No
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
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Minor components: 15 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)
Hydric soil rating: No
Minor Components
Nunn
Percent of map unit: 10 percent
Landform: Terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Loamy Plains (R067BY002CO)
Hydric soil rating: No
Vona
Percent of map unit: 5 percent
Landform: Interfluves
Landform position (two-dimensional): Backslope, footslope
Landform position (three-dimensional): Side slope, base slope
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Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Sandy Plains (R067BY024CO)
Hydric soil rating: No
36—Fort Collins loam, 3 to 5 percent slopes
Map Unit Setting
National map unit symbol: jpw9
Elevation: 4,800 to 5,500 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
Fort collins and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Fort Collins
Setting
Landform: Terraces, fans
Landform position (three-dimensional): Base slope, riser
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium
Typical profile
H1 - 0 to 9 inches: loam
H2 - 9 to 20 inches: loam, clay loam
H2 - 9 to 20 inches: loam, silt loam, fine sandy loam
H3 - 20 to 60 inches:
H3 - 20 to 60 inches:
H3 - 20 to 60 inches:
Properties and qualities
Slope: 3 to 5 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: 15 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
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Available water storage in profile: Very high (about 25.5 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Ecological site: Loamy Plains (R067XY002CO)
Hydric soil rating: No
Minor Components
Ascalon
Percent of map unit: 5 percent
Hydric soil rating: No
Kim
Percent of map unit: 3 percent
Hydric soil rating: No
Stoneham
Percent of map unit: 2 percent
Hydric soil rating: No
37—Fort Collins loam, 5 to 9 percent slopes
Map Unit Setting
National map unit symbol: jpwb
Elevation: 4,800 to 5,500 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: Farmland of statewide importance
Map Unit Composition
Fort collins and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Fort Collins
Setting
Landform: Terraces, fans
Landform position (three-dimensional): Base slope, riser
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium
Typical profile
H1 - 0 to 6 inches: loam
H2 - 6 to 18 inches: loam, clay loam
H2 - 6 to 18 inches: loam, silt loam, fine sandy loam
H3 - 18 to 60 inches:
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H3 - 18 to 60 inches:
H3 - 18 to 60 inches:
Properties and qualities
Slope: 5 to 9 percent
Depth to restrictive feature: More than 80 inches
Natural 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 in profile: 15 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: Very high (about 26.4 inches)
Interpretive groups
Land capability classification (irrigated): 4e
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: B
Ecological site: Loamy Plains (R067XY002CO)
Hydric soil rating: No
Minor Components
Larimer
Percent of map unit: 8 percent
Hydric soil rating: No
Kim
Percent of map unit: 4 percent
Hydric soil rating: No
Stoneham
Percent of map unit: 3 percent
Hydric soil rating: No
55—Kim loam, 5 to 9 percent slopes
Map Unit Setting
National map unit symbol: jpwz
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: Farmland of local importance
Map Unit Composition
Kim and similar soils: 85 percent
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Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Kim
Setting
Landform: Fans
Landform position (three-dimensional): Base slope, side slope
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Mixed alluvium
Typical profile
H1 - 0 to 7 inches: loam
H2 - 7 to 60 inches: loam, clay loam, sandy clay loam
H2 - 7 to 60 inches:
H2 - 7 to 60 inches:
Properties and qualities
Slope: 5 to 9 percent
Depth to restrictive feature: More than 80 inches
Natural 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 in profile: 15 percent
Salinity, maximum in profile: Nonsaline to slightly saline (0.0 to 4.0 mmhos/cm)
Available water storage in profile: Very high (about 26.5 inches)
Interpretive groups
Land capability classification (irrigated): 4e
Land capability classification (nonirrigated): 6e
Hydrologic Soil Group: B
Ecological site: Loamy Plains (R067XY002CO)
Hydric soil rating: No
Minor Components
Thedalund
Percent of map unit: 10 percent
Hydric soil rating: No
Stoneham
Percent of map unit: 5 percent
Hydric soil rating: No
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63—Longmont clay, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: jpx8
Elevation: 4,800 to 5,800 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 and reclaimed of excess salts
and sodium
Map Unit Composition
Longmont and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Longmont
Setting
Landform: Flood plains, valleys
Landform position (three-dimensional): Base slope, tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Clayey alluvium derived from shale
Typical profile
H1 - 0 to 60 inches: clay
Properties and qualities
Slope: 0 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Poorly drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: About 24 to 30 inches
Frequency of flooding: Occasional
Frequency of ponding: None
Calcium carbonate, maximum in profile: 15 percent
Gypsum, maximum in profile: 5 percent
Salinity, maximum in profile: Slightly saline to strongly saline (4.0 to 16.0
mmhos/cm)
Sodium adsorption ratio, maximum in profile: 20.0
Available water storage in profile: Moderate (about 8.4 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 6w
Hydrologic Soil Group: D
Ecological site: Salt Meadow (R067BY035CO)
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Hydric soil rating: No
Minor Components
Dacono
Percent of map unit: 5 percent
Hydric soil rating: No
Aquolls
Percent of map unit: 5 percent
Landform: Swales
Hydric soil rating: Yes
Heldt
Percent of map unit: 5 percent
Hydric soil rating: No
73—Nunn clay loam, 0 to 1 percent slopes
Map Unit Setting
National map unit symbol: 2tlng
Elevation: 4,100 to 5,700 feet
Mean annual precipitation: 14 to 15 inches
Mean annual air temperature: 48 to 52 degrees F
Frost-free period: 135 to 152 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Nunn and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Nunn
Setting
Landform: Terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Pleistocene aged alluvium and/or eolian deposits
Typical profile
Ap - 0 to 6 inches: clay loam
Bt1 - 6 to 10 inches: clay loam
Bt2 - 10 to 26 inches: clay loam
Btk - 26 to 31 inches: clay loam
Bk1 - 31 to 47 inches: loam
Bk2 - 47 to 80 inches: loam
Properties and qualities
Slope: 0 to 1 percent
Depth to restrictive feature: More than 80 inches
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Natural drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 7 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): 3e
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: C
Ecological site: Clayey Plains (R067BY042CO)
Hydric soil rating: No
Minor Components
Heldt
Percent of map unit: 10 percent
Landform: Terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Clayey Plains (R067BY042CO)
Hydric soil rating: No
Wages
Percent of map unit: 5 percent
Landform: Terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Loamy Plains (R067BY002CO)
Hydric soil rating: No
74—Nunn clay loam, 1 to 3 percent slopes
Map Unit Setting
National map unit symbol: 2tlpl
Elevation: 3,900 to 5,840 feet
Mean annual precipitation: 13 to 17 inches
Mean annual air temperature: 50 to 54 degrees F
Frost-free period: 135 to 160 days
Farmland classification: Prime farmland if irrigated
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Map Unit Composition
Nunn and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Nunn
Setting
Landform: Terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Pleistocene aged alluvium and/or eolian deposits
Typical profile
Ap - 0 to 9 inches: clay loam
Bt - 9 to 13 inches: clay loam
Btk - 13 to 25 inches: clay loam
Bk1 - 25 to 38 inches: clay loam
Bk2 - 38 to 80 inches: clay loam
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 7 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.1 to 2.0
mmhos/cm)
Sodium adsorption ratio, maximum in profile: 0.5
Available water storage in profile: High (about 9.9 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: Clayey Plains (R067BY042CO)
Hydric soil rating: No
Minor Components
Heldt
Percent of map unit: 10 percent
Landform: Terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Clayey Plains (R067BY042CO)
Hydric soil rating: No
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Satanta
Percent of map unit: 5 percent
Landform: Terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Loamy Plains (R067BY002CO)
Hydric soil rating: No
76—Nunn clay loam, wet, 1 to 3 percent slopes
Map Unit Setting
National map unit symbol: jpxq
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
Nunn, wet, and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Nunn, Wet
Setting
Landform: Alluvial fans, stream terraces
Landform position (three-dimensional): Base slope, tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium
Typical profile
H1 - 0 to 10 inches: clay loam
H2 - 10 to 47 inches: clay loam, clay
H2 - 10 to 47 inches: clay loam, loam, gravelly sandy loam
H3 - 47 to 60 inches:
H3 - 47 to 60 inches:
H3 - 47 to 60 inches:
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Somewhat poorly drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.60 in/hr)
Depth to water table: About 24 to 36 inches
Frequency of flooding: Rare
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Frequency of ponding: None
Calcium carbonate, maximum in profile: 10 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: Very high (about 19.8 inches)
Interpretive groups
Land capability classification (irrigated): 2w
Land capability classification (nonirrigated): 3s
Hydrologic Soil Group: C
Hydric soil rating: No
Minor Components
Heldt
Percent of map unit: 6 percent
Hydric soil rating: No
Dacono
Percent of map unit: 3 percent
Hydric soil rating: No
Mollic halaquepts
Percent of map unit: 1 percent
Landform: Swales
Hydric soil rating: Yes
79—Otero sandy loam, 5 to 9 percent slopes
Map Unit Setting
National map unit symbol: jpxt
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: Not prime farmland
Map Unit Composition
Otero and similar soils: 80 percent
Minor components: 20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Otero
Setting
Landform: Fans
Landform position (three-dimensional): Base slope, side slope
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium and/or eolian deposits
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Typical profile
H1 - 0 to 14 inches: sandy loam
H2 - 14 to 60 inches: sandy loam, fine sandy loam, loamy very fine sand
H2 - 14 to 60 inches:
H2 - 14 to 60 inches:
Properties and qualities
Slope: 5 to 9 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Somewhat excessively drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): High (2.00 to 6.00
in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 5 percent
Salinity, maximum in profile: Nonsaline to slightly saline (0.0 to 4.0 mmhos/cm)
Available water storage in profile: Very high (about 15.4 inches)
Interpretive groups
Land capability classification (irrigated): 4e
Land capability classification (nonirrigated): 6e
Hydrologic Soil Group: A
Ecological site: Sandy Plains (R067BY024CO)
Hydric soil rating: No
Minor Components
Kim
Percent of map unit: 9 percent
Hydric soil rating: No
Nelson
Percent of map unit: 6 percent
Hydric soil rating: No
Tassel
Percent of map unit: 5 percent
Hydric soil rating: No
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Soil Information for All Uses
Soil Properties and Qualities
The Soil Properties and Qualities section includes various soil properties and
qualities displayed as thematic maps with a summary table for the soil map units in
the selected area of interest. A single value or rating for each map unit is generated
by aggregating the interpretive ratings of individual map unit components. This
aggregation process is defined for each property or quality.
Soil Qualities and Features
Soil qualities are behavior and performance attributes that are not directly
measured, but are inferred from observations of dynamic conditions and from soil
properties. Example soil qualities include natural drainage, and frost action. Soil
features are attributes that are not directly part of the soil. Example soil features
include slope and depth to restrictive layer. These features can greatly impact the
use and management of the soil.
Hydrologic Soil Group
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.
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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.
Custom Soil Resource Report
31
32
Custom Soil Resource Report
Map—Hydrologic Soil Group
44833004483400448350044836004483700448380044839004484000448410044842004484300448440044845004483300448340044835004483600448370044838004483900448400044841004484200448430044844004484500495900 496000 496100 496200 496300 496400 496500 496600 496700
495900 496000 496100 496200 496300 496400 496500 496600 496700
40° 30' 41'' N 105° 2' 58'' W40° 30' 41'' N105° 2' 16'' W40° 29' 58'' N
105° 2' 58'' W40° 29' 58'' N
105° 2' 16'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 300 600 1200 1800
Feet
0 50 100 200 300
Meters
Map Scale: 1:6,420 if printed on A portrait (8.5" x 11") 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
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 11, Sep 23, 2016
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Mar 20, 2015—Oct
15, 2016
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
33
Table—Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
5 Aquepts, loamy A/D 15.4 8.8%
22 Caruso clay loam, 0 to 1
percent slope
D 4.0 2.3%
34 Fort Collins loam, 0 to 1
percent slopes
B 1.9 1.1%
35 Fort Collins loam, 0 to 3
percent slopes
C 8.6 4.9%
36 Fort Collins loam, 3 to 5
percent slopes
B 30.9 17.6%
37 Fort Collins loam, 5 to 9
percent slopes
B 1.1 0.6%
55 Kim loam, 5 to 9 percent
slopes
B 4.4 2.5%
63 Longmont clay, 0 to 3
percent slopes
D 6.6 3.8%
73 Nunn clay loam, 0 to 1
percent slopes
C 23.5 13.4%
74 Nunn clay loam, 1 to 3
percent slopes
C 67.6 38.5%
76 Nunn clay loam, wet, 1 to
3 percent slopes
C 3.8 2.2%
79 Otero sandy loam, 5 to 9
percent slopes
A 7.7 4.4%
Totals for Area of Interest 175.6 100.0%
Rating Options—Hydrologic Soil Group
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Custom Soil Resource Report
34
References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
home/?cid=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
35
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
Custom Soil Resource Report
36
NORTHERNENGINEERING.COM | 970.221.4158
FORT COLLINS | GREELEY
PRELIMINARY DRAINAGE REPORT: THE FLATS AT HANSEN FARM
APPENDIX
MAP POCKET
DR1 – DRAINAGE EXHIBIT
UDUDUD
UD
UD
UD FMFMFM/ / / / / / / // / / / / / / // / / / / / / // / / / / / / /XXXXXX X
CC1
O2
E
D
D2
E2
O4
B
A
B1
KNOBBY PINE DRIVE
ZEPHYR ROADBURLY TREE DRIVETWISTED ROOT DRIVE
SOUTH TIMBERLINE ROADPROPOSED
STORM DRAIN
PROPOSED
STORM DRAIN
EXISTING
STORM DRAIN
PROPOSED
STORM DRAIN
RAIN
GARDEN A
RAIN
GARDEN B
RAIN
GARDEN C
RAIN
GARDEN D
RAIN
GARDEN E
DETENTION
POND 3
EXISTING
DETENTION POND 2
EXISTING
DETENTION POND 1
EXISTING DETENTION
POND 4
EXISTING
STORM DRAIN
EXISTING
STORM DRAIN
EXISTING
STORM DRAINS
EXISTING
STORM DRAIN
A
B
C
D
E
C1
O2
B1
O3
E2
O4
O1
D1
D2
E1
PROPOSED 2'
CONCRETE PAN
O3
E1
D1
PROPOSED 2'
CONCRETE PAN
PROPOSED
STORM DRAIN
O1
SheetTHE FLATS AT HANSEN FARMThese drawings areinstruments of serviceprovided by NorthernEngineering Services, Inc.and are not to be used forany type of constructionunless signed and sealed bya Professional Engineer inthe employ of NorthernEngineering Services, Inc.NOT FOR CONSTRUCTIONREVIEW SETof 17
NORTH
( IN FEET )
1 inch = ft.
Feet05050
50
100 150
CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU
DIG, GRADE, OR EXCAVATE FOR THE MARKING OF
UNDERGROUND MEMBER UTILITIES.
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what'sbelow.
before you dig.Call
R
C 700DRAINAGE EXHIBIT 17
PROPOSED CONTOUR
PROPOSED STORM SEWER
PROPOSED SWALE
EXISTING CONTOUR
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
A
DESIGN POINT
FLOW ARROW
DRAINAGE BASIN LABEL
DRAINAGE BASIN BOUNDARY
PROPOSED SWALE SECTION
11
NOTES:
1.REFER TO THE PRELIMINARY DRAINAGE REPORT FOR THE FLATS AT HANSEN
FARMS, DATED JUNE 29, 2022 FOR ADDITIONAL INFORMATION.
A
LEGEND:
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
Rational Flow Summary | Developed Basin Flow Rates
BASIN
TOTAL
AREA
(acres)
Tc2
(min)
Tc100
(min)
C2 C100 Q2
(cfs)
Q100
(cfs)
A 1.37 5.0 5.0 0.78 0.83 3.05 11.32
B 0.59 6.5 5.9 0.62 0.67 0.95 3.82
B1 0.36 5.2 5.0 0.73 0.78 0.75 2.80
C 0.72 6.7 6.1 0.76 0.81 1.42 5.42
C1 1.07 5.0 5.0 0.72 0.79 2.19 8.38
D 1.27 7.6 7.1 0.34 0.40 1.06 4.46
D1 0.54 5.0 5.0 0.90 0.95 1.39 5.12
D2 0.49 5.0 5.0 0.84 0.89 1.16 4.30
E 2.17 5.0 5.0 0.84 0.89 5.20 19.23
E1 0.21 5.0 5.0 0.86 0.91 0.52 1.91
E2 0.35 5.7 5.2 0.62 0.67 0.60 2.35
O1 0.11 7.5 7.0 0.25 0.31 0.07 0.31
O2 0.93 5.0 5.0 0.74 0.81 1.96 7.51
O3 0.06 5.0 5.0 0.33 0.39 0.05 0.22
O4 0.15 5.0 5.0 0.33 0.39 0.14 0.57
Combined Basins
East Side 6.17 12.5 12.5 0.70 0.76 8.85 33.55
West Side 4.22 12.5 12.5 0.72 0.78 6.12 23.16
On-Site LID Treatment
Project Summary
Total Impervious Area 271,470 sf
Target Treatment Percentage 89%
Minimum Area to be Treated by LID measures 240,400 sf
Rain Garden Area
Rain Garden Area 6,461 sf
Run-on area for Rain Gardens 339,818 sf
Total Rain Garden Treatment Area 346,279 sf
Overall Run-on Ratio for Rain Garden (50:1 Max) 53 :1
Total Treatment Area 240,400 sf
Percent Total Project Area Treated 88.6%