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PRELIMINARY DRAINAGE REPORT
THE QUARRY BY WATERMARK
FORT COLLINS, COLORADO
May 5, 2021
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970.221.4158
FORT COLLINS
GREELEY
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FORT COLLINS | GREELEY COVER LETTER
May 3, 2021
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, CO 80521
RE: PRELIMINARY DRAINAGE REPORT FOR
THE QUARRY BY WATERMARK
Dear Staff,
Northern Engineering is pleased to submit this Preliminary Drainage Report for your review. This report
accompanies the combined Preliminary Plan submittal for the proposed The Quarry by Watermark
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 Quarry by Watermark housing
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
I hereby attest that this report for the preliminary drainage design for The Quarry by Watermark 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.
Registered professional engineer must affix their seal with signature and date. (for final report)
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FORT COLLINS | GREELEY TABLE OF CONTENTS
TABLE OF CONTENTS
I. GENERAL LOCATION AND DESCRIPTION ................................................................ 1
II. DRAINAGE BASINS AND SUB-BASINS ..................................................................... 3
III. DRAINAGE DESIGN CRITERIA ................................................................................ 4
IV. DRAINAGE FACILITY DESIGN ................................................................................. 6
V. CONCLUSIONS .................................................................................................. 10
VI. REFERENCES .................................................................................................... 11
TABLES AND FIGURES
Figure 1 – Vicinity Map ........................................................................................................1
Figure 2 – Aerial Photograph ..............................................................................................2
Figure 3 – FEMA Firmette (Map Numbers 08069CO978G and 08069CO979H) ..................3
APPENDICES
APPENDIX A – HYDROLOGIC COMPUTATIONS
APPENDIX B – HYDRAULIC COMPUTATIONS
APPENDIX C – WATER QUALITY COMPUTATIONS
APPENDIX D – DETENTION POND & SWMM MODEL
APPENDIX E – EROSION CONTROL REPORT
APPENDIX F – USDA SOILS REPORT
APPENDIX G – FEMA FIRMETTE
MAP POCKET
DR1 – DRAINAGE EXHIBIT
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I. GENERAL LOCATION AND DESCRIPTION
A. LOCATION
Vicinity Map
Figure 1 – Vicinity Map
The Quarry by Watermark project site is located in the northwest quarter of Section 23, Township
7 North, Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State
of Colorado.
The project site (refer to Figure 1) is bordered to the north by Hobbit Street; to the east by Canal
Importation Ditch; to the south by Spring Creek; and to the west by Shields Street.
Spring Creek and Canal Importation Ditch are a major drainageways located adjacent to the
project site. The confluence of Spring Creek and Canal Importation Ditch is in the southeast
corner of the site.
B. DESCRIPTION OF PROPERTY
The Quarry by Watermark comprises of ± 19.38 acres.
The site is currently an undeveloped parcel surrounded by multi-family to the north, west, and
south and single-family homes to the east
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Figure 2 – Aerial Photograph
The existing groundcover consists of short grasses. The existing on-site runoff generally drains
from the northwest to the southeast across flat grades (e.g., <1.00%) into the Canal Importation
Ditch. From there, the drainage continues through Canal Importation Ditch to Spring Creek, and
on to the Cache La Poudre River.
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 Altvan-Satanta loams (Hydrologic Soil Group B) and Nunn clay loam
(Hydrological Soil Group C).
Springs Creek and Canal Importation Ditch are the only major drainageways within or adjacent
to the project site.
The proposed development will consist of seventeen (17) townhome buildings containing a total
of 313 units with detached garages. Other proposed improvements include parking lots,
sidewalks, pool, clubhouse, and landscaping.
The proposed land use is multi-family. This is a permitted use in the Medium-Density Mixed-Use
Neighborhood District (MMN).
C. FLOODPLAIN
1. The eastern and southern edges of the site is in a FEMA regulatory floodplain; however, the
developable project area is outside of the FEMA floodplain. In particular, the FEMA designated
100-year floodplain Basins E1 and E2 on the Drainage Exhibit includes the FEMA regulatory
floodplains for Spring Creek and Canal Importation Ditch (Map Numbers 08069CO978G and
08069CO979H and effective date of May 2, 2012). The eastern portion on this site, along the
Canal Importation Ditch, is located within the City of Fort Collins Regulatory
floodplain/floodway. No development is proposed within Basins E1 and E2. A copy of the FEMA
Firmette is provided in Appendix G.
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2. We have analyzed the FEMA Floodplain map and cross sections for Spring Creek and Canal
Importation Ditch and determined that the highest base flood elevation adjacent to the project
site is 5016 (NAVD88). All buildings have been elevated 1.5’ above this elevation. Furthermore, the
buildings all maintain a minimum of 12” between the finished floor elevation and the top of bank
along the south and east side of the property.
II. DRAINAGE BASINS AND SUB-BASINS
A. Major Basin Description
The north and east halves of The Quarry by Watermark is located within the City of Fort Collins Canal
Importation major drainage basin. The southwest quarter of the site is located within the City of Fort
Collins Spring Creek major drainage basin. Specifically, the project site is situated at the confluence
of the Spring Creek and Canal Importation major drainage basins. Detention requirements for this
basin are to detain the difference between the 100-yr developed inflow rate and the historic 2-year
release rate.
B. Sub-Basin Description
The outfall for the project site is at the confluence of Springs Creek and Canal Importation Basins.
The existing subject site can be defined with twelve (22) sub-basins that encompasses the entire
project site and three (3) offsite basins that drain onto the project site.
The existing site runoff generally drains from northwest-to-southeast and into the Canal
Importation Ditch.
The project site receives runoff from Shields Street and Hobbit Street.
Figure 3 – FEMA Firmette (Map Numbers 08069CO978G and 08069CO979H)
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III. DRAINAGE DESIGN CRITERIA
A. Optional Provisions
There are no optional provisions outside of the FCSCM proposed with the Quarry by Watermark.
B. STORMWATER MANAGEMENT STRATEGY
The overall stormwater management strategy employed with The Quarry by Watermark 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 Quarry by Watermark 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 underground vaults located at the
south end of the project and a single rain garden along the east side of the property. The remaining
runoff will be treated for water quality in the proposed detention ponds along the Spring Creek.
Step 3 – Stabilize Drainageways. As stated in Section I.B.6, above, the Spring Creek and Canal
Importation drainage is adjacent to the subject site, however no changes to the channel are
proposed with this project. While this step may not seem applicable to The Quarry by Watermark, the
proposed project indirectly helps achieve stabilized drainageways, nonetheless. Once again, site
selection has a positive effect on stream stabilization. By developing an infill site with stormwater
infrastructure, combined with LID and MDCIA strategies, the likelihood of bed and bank erosion and
the frequency of erosive flows are reduced. Furthermore, this project will pay one-time stormwater
development fees, as well as ongoing monthly stormwater utility fees, both of 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
The subject property is not part of any Overall Development Plan (ODP) drainage study or similar
“development/project” drainage master plan.
The site plan is constrained to the north and west by public streets, to the south by Spring Creek,
and to the east by the Canal Importation Ditch.
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D. HYDROLOGICAL CRITERIA
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 Quarry by
Watermark development. Tabulated data contained in Table 3.4-1 has been utilized for Rational
Method runoff calculations.
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.
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
The drainage facilities proposed with The Quarry by Watermark project are designed in
accordance with criteria outlined in the FCSCM.
As stated in Section I.C.1, above, the subject property is located next to a FEMA designated
floodplain but is not located within the floodplain limits.
F. FLOODPLAIN REGULATIONS COMPLIANCE
As previously mentioned, this project is adjacent to a FEMA regulated floodplain. The
developable area of the project is located outside of the floodplain, and as such, it will not be
subject to any floodplain regulations. However, the storm outfall will be located within the
floodway, and that work will be subject to the applicable floodplain regulations of Chapter 10 of
the City Municipal Code.
Despite most of the project not being located within the floodplain, consideration has been given
to the floodplain elevations as they relate to the proposed buildings and the finished floors have
been elevated accordingly.
G. MODIFICATIONS OF CRITERIA
There are no optional provisions outside of the FCSCM proposed with the Quarry by Watermark.
H. CONFORMANCE WITH WATER QUALITY TREATMENT CRITERIA
City Code requires that 100% of runoff from impervious surfaces in a project site shall receive some
sort of water quality treatment. This project proposes to provide water quality treatment using
several methods. A single rain garden will be located along the east edge of the site. Two separate
areas along the south side of the site will use underground chambers for treatment. Both areas will
discharge into two proposed detention ponds that will provide water quality for the remainder of the
site before discharge into the Canal Importation Basin. Due to the physical constraints associated
with an infill project of this nature and the prohibition of providing water quality facilities within the
public right-of-way, there are some small, narrow areas around the perimeter of the project that
cannot be captured. The uncaptured areas tend to be narrow strips of concrete flatwork that link the
building entrances to the public sidewalks as well as small planter beds between the building and
public sidewalks or property lines.
While these small areas will not receive formal water quality treatment, most areas will still see some
treatment as runoff is directed across through the landscaped areas or across the landscaped
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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. A single rain garden and underground chambers will be used to capture and filter or
infiltrate the water quality capture volume.
J. SIZING OF LID FACILITIES
Rain Gardens/Underground Chambers
1. The rain gardens and chambers were sized by first determining the required water quality
capture volume (WQCV) for Basins B1-B7 for the rain garden and Basins A2 & D4-7 for the
chambers. A 12-hour drain time was used in this calculation.
2. Once the WQCV was identified, each rain garden and chamber area were 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.
Water Quality Pond
1. The water quality pond was sized by first determining the required water quality capture
volume (WQCV) for Basins D1 and A3. Offsite flows from Basins OS1 and OS2 (Shields Street)
will be treated in the water quality ponds. A 40-hour drain time was used in this calculation.
2. Once the WQCV was identified, the water quality pond was sized to provide the WQCV. An
outlet control structure with overflow will be provided to pass storms greater than the WQCV.
Table 2 – 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
306,568 69% 5,621 6,745 211,722
Stormtech 1 76,238 77% 1,578 1,894 58,703
Stormtech 2 81,341 58% 1,247 1,496 47,552
IV. DRAINAGE FACILITY DESIGN
A. GENERAL CONCEPT
1. The main objective of The Quarry by Watermark 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.
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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 analyzed using twenty-one (22) onsite drainage sub-
basins, designated as sub-basins A1- A2, B1-B7, C1-C2, D1-D7, E1-E2, and F1-F2. Furthermore,
there are three (3) offsite drainage sub-basins designated as sub-basins OS1, OS2, and OS3.
The drainage patterns anticipated for the basins are further described below.
Sub-Basins A1
Sub-Basin A1 encompasses approximately 7% of the total site area. Basin A1 contains Detention
Pond 1 which is the collection point of all B sub-basins on site before release into the Canal
Importation Ditch. This pond, in conjunction with Detention Pond 2, will moderate the release
rate into the ditch during the Major Storm. An outlet structure with a restrictor plate will be
installed with Pond 1 and an outfall pipe will be used for the discharge into the Canal
Importation Ditch. Emergency Overflow from this pond will be directed into the Canal
Importation Ditch.
Sub-Basins A2
Sub-Basin A2 encompasses approximately 9% of the total site area. Basin A2 is comprised
primarily of roof area, concrete flatwork, parking lot and landscaped areas. This basin will drain
into a valley pan and curb and gutter located in the parking lot and be captured by an inlet and
storm drain. This area will be treated by Stormtech Chambers 2, located just south of the
collection point. The WQCV will be captured in these chambers during the minor storm and flow
from larger storms will then proceed to Detention Pond 1 and the Canal Importation Ditch. Sub-
basin A2 will be passed through Pond 1 and will not be detained. Sub-basin A2 will be passed
through the spillway to be designed at Final for Pond 1, and will not be detained as part of the
“area trade” as discussed in Section IV.B, below.
Sub-Basin B1 – B7
Sub-Basins B1 through B7 encompasses approximately 36% the total site area. Basin B1 mainly
comprises of Rain Garden A, which will be the main treatment method for the B sub-basins.
Minor flows will be treated in this rain garden, while flows from larger storms will proceed to
Detention Pond 1 and to the Canal Importation ditch. The remaining sub-basins (B2-B7) are
comprised primarily of roof area, concrete flatwork, parking lot, and landscaped areas. The sub-
basins will drain into a valley pan and curb & gutter located within each sub-basin and towards a
common storm sewer. This common storm sewer will discharge into Rain Garden A. Storm
sewers will be sized to convey major storms.
Sub-Basin C1
Sub-basin C1 is comprised of an existing ditch along the north property line (Ditch C). This
existing ditch conveys runoff from OS3 (Hobbit Street) and discharges directly into the Canal
Importation Ditch. This is an existing condition and there will be no added flows or change in
drainage patterns.
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Sub-Basin C2
This sub-basin is comprised primarily of roof area, concrete flatwork, and landscaped areas.
Flows from the sub-basin will flow north into curb and gutter along Hobbit Street. Hobbit Street
will convey runoff, along with drainage from Sub-Basin OS3 to Ditch C. Flows will then proceed
to the Canal Importation Ditch.
Sub-Basin D1
Sub-Basin D1 encompasses approximately 5% the total site area. This basin contains Detention
Pond 2, which will collect runoff from Sub-Basins D, F, and the offsite flows from Shields (OS1 &
OS2). Detention Pond 2 will serve as the water quality pond for the remaining basins that are not
treated with LID. An outlet structure will be constructed with a water quality plate and restrictor
plate. The outfall for Pond 2 will discharge around Pond 1. Emergency overflow from detention
pond 2 will spill into detention pond 1 prior to discharging into the Canal Importation Ditch.
Sub-Basin D2
Sub-Basin D2 encompasses approximately 1% the total site area. This sub-basin is comprised
primarily of primarily of landscaped areas. No development is proposed in this area and flows
from the sub-basin will discharge directly into Spring Creek.
Sub-Basin D3
These sub-basins are comprised primarily of roof area, concrete flatwork, parking lot, and
landscaped areas. The sub-basins will drain into a common storm sewer via valley pans and
curb and gutter. The storm sewer will collect drainage from all the sub-basins, including Sub-
Basins OS1 and OS2, and discharge into Detention Pond 2. Flows will then proceed to the Canal
Importation Ditch.
Sub-Basin D4-D7
Sub-Basins D4-D7 encompass approximately 14% the total site area. These sub-basins are
comprised primarily of roof area, concrete flatwork, parking lot, and landscaped areas. The sub-
basins will drain into a common storm sewer via valley pans and curb and gutter. The storm
sewer will collect drainage from all the sub-basins and discharge into Stormtech Chambers 1.
The WQCV will be captured in these chambers during minor flows. Larger flows will bypass the
chambers and discharge directly into Detention Pond 2. Flows will then proceed to the Canal
Importation Ditch. Storm sewer will be sized to convey major storms.
Sub-Basin E1
Sub-basin E1 encompasses approximately 17% the total site area. This sub-basin comprises of
the Spring Creek flood plain. No improvements, except for storm sewer outfalls, are proposed
within this sub-basin
Sub-Basin E2
Sub-basin E2 encompasses approximately 7% the total site area. This sub-basin comprises of the
Canal Importation flood plain. No improvements, except for storm sewer outfalls, are proposed
within this sub-basin
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Sub-Basins F1 & F2
Sub-basins F1 and F2 encompass approximately 1% the total site area. These sub-basins are
comprised primarily of concrete flatwork and landscaped areas. Flows from the sub-basin will
drain into curb and gutter along Shield Street. The curb and gutter will then convey the flows to
the intersection of Shields Street and Stuart Street (also the west entrance of the site), into Sub-
Basin D3, and ultimately Detention Pond 2. Flows will then proceed to the Canal Importation
Ditch.
Sub-Basin OS1 & OS2
Offsite Sub-Basins OS1 and OS2 consist of the west edge of Shields Street that directly impacts
the project site. These sub-basins are comprised primarily of asphalt, concrete flatwork, and a
landscaped parkway. Flows from the sub-basin will drain into curb and gutter along Shield
Street. The curb and gutter will then convey the flows to the intersection of Shields Street and
Stuart Street (also the west entrance of the site), into Sub-Basin D3, and ultimately into Water
Quality Pond D. 1,7 of the 2.5 acres will be detained and treated in Pond 2. The remaining 0.8
acres will pass through the detention pond.
Sub-Basin OS3
Offsite Sub-Basin OS3 consists of Hobbit Street north of the project site. This sub-basin is
comprised primarily of asphalt and concrete flatwork. Flows from the sub-basin will drain into
curb and gutter along Hobbit Street. The curb and gutter will then convey the flows to Ditch C
and ultimately into the Canal Importation Ditch.
A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report.
B. SPECIFIC DETAILS
Two detention ponds are proposed with this development and will detain up to the 100-yr storm
event and release at or below the caluclated release rate. A SWMM model was created to deterim
the detention volumes. See Appendix C for more detail. See Table 2 for detention summary and
Table 3 for an allowable release summary.
Table 2 – Detention Summary
Table 3 – Allowable Release Summary
Pond ID
100-Yr. Detention Vol.
(Ac-Ft) Peak Release (cfs) WQCV (Ac-Ft)
Pond 1 1.99 5.10 n/a
Pond 2 0.89 5.60 0.13
POND SUMMARY TABLE
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LID treatment is being provided within Rain Garden 1 and Stormtech Chambers 1 & 2. These
provide mare that the required LID treatement of 75% of the impervious site runoff. Please see
the LID exhibt and calculations in Appendix C.
Detention allowable release rate is based on computed 2-year historic flow for the overall
property. We have added historic flow from Right of Way area in addition to the property. Basins
OS1 and OS2 (Please see Historic Drainage Exhibit), with a combined area of 2.28 acres, will be
taken into Pond 2 and will be detained. Thus, we have added 2-year historic flow from these
basins to the site allowable release. We proposed an “area trade” which allows for the free
release of developed basin A2, with an area od 1.75 acres. We will detain 1.75 acres of offsite
basins OS1 and OS2 (combined area of 2.28 acres), and in exchange, we will be allowed to free
release basin A2. Based on historic flow computations provided in the appendix, the summation
of onsite historic 2-year flow and 2-year flows from Basins OS1 and OS2 is 6.4 cfs (as summarized
in Table 3). We propose to release slightly below this rate as shown in Table 2, above.
Stormwater facility Standard Operations Procedures (SOP) will be provided by the City of Fort
Collins in the Development Agreement.
Final Design details, and construction documentation shall be provided to the City of Fort Collins
for review prior to Final Development Plan approval.
V. CONCLUSIONS
A. COMPLIANCE WITH STANDARDS
The drainage design proposed with The Quarry by Watermark complies with the City of Fort
Collins Master Drainage Plan for the Spring Creek and Canal Importation Basins.
The project is adjacent to the Spring Creek and Canal Importation FEMA regulatory floodplains.
However, the development is constructed outside of the floodplains, and buildings are located
18-inches above the base flood elevation. No improvements are proposed within the FEMA
regulated floodplains. All applicable provisions within Chapter 10 of the City Municipal Code
shall be adhered to.
The drainage plan and stormwater management measures proposed with The Quarry by
Watermark project are compliant with all applicable State and Federal regulations governing
stormwater discharge.
B. DRAINAGE CONCEPT
The drainage plan and stormwater management measures proposed with The Quarry by
Watermark project are compliant with all applicable State and Federal regulations governing
stormwater discharge.
The Quarry by Watermark will not impact the Master Drainage Plan recommendations for the
Canal Importation and Spring Creek major drainage basin.
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VI. REFERENCES
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.
Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service, United
States Department of Agriculture.
Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District, Wright-
McLaughlin Engineers, Denver, Colorado, Revised April 2008.
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FORT COLLINS | GREELEY APPENDIX
APPENDIX A
HYDROLOGIC COMPUTATIONS
Runoff
Coefficient 1
Percent
Impervious1
0.95 100%
0.95 90%
0.50 40%
0.50 40%
0.20 2%
0.20 2%
Basin ID Basin Area
(sq.ft.)
Basin Area
(acres)
Asphalt,
Concrete (acres)Rooftop (acres) Gravel (acres) Pavers (acres)
Undeveloped:
Greenbelts,
Agriculture
(acres)
Lawns, Clayey
Soil, Flat Slope <
2% (acres)
Percent
Impervious
C2*Cf
Cf = 1.00
C5*Cf
Cf = 1.00
C10*Cf
Cf = 1.00
C100*Cf
Cf = 1.25
H-A1 44,062 1.012 0.000 0.000 0.000 0.000 1.012 0.000 2%0.20 0.20 0.20 0.25
H-A2 6,773 0.155 0.000 0.000 0.000 0.000 0.155 0.000 2%0.20 0.20 0.20 0.25
H-B1 110,004 2.525 0.000 0.000 0.000 0.000 2.525 0.000 2%0.20 0.20 0.20 0.25
H-B2 170,633 3.917 0.015 0.000 0.000 0.000 3.902 0.000 2%0.20 0.20 0.20 0.25
H-B3 19,023 0.437 0.020 0.000 0.000 0.000 0.417 0.000 6%0.23 0.23 0.23 0.29
H-C1 32,204 0.739 0.000 0.000 0.000 0.000 0.739 0.000 2%0.20 0.20 0.20 0.25
H-C2 238,190 5.468 0.009 0.000 0.000 0.000 5.459 0.000 2%0.20 0.20 0.20 0.25
H-D1 7,509 0.172 0.000 0.000 0.000 0.000 0.172 0.000 2%0.20 0.20 0.20 0.25
H-E1 147,424 3.384 0.283 0.019 0.000 0.000 3.082 0.000 11%0.27 0.27 0.27 0.33
H-E2 60,287 1.384 0.143 0.002 0.000 0.000 1.239 0.000 12%0.28 0.28 0.28 0.35
H-F1 1,947 0.045 0.028 0.000 0.000 0.000 0.000 0.017 64%0.67 0.67 0.67 0.84
H-F2 7,695 0.177 0.094 0.000 0.000 0.000 0.000 0.082 54%0.60 0.60 0.60 0.75
OS1 21,067 0.484 0.407 0.000 0.000 0.000 0.000 0.077 84%0.83 0.83 0.83 1.00
OS2 78,428 1.800 1.706 0.000 0.000 0.000 0.000 0.094 95%0.91 0.91 0.91 1.00
Comb OS1,
OS2 99,495 2.284 0.000 0.000 0.000 0.000 0.000 2.284 2%0.20 0.20 0.20 0.25
OS3 20,406 0.468 0.405 0.000 0.000 0.000 0.000 0.063 87%0.25 0.25 0.25 0.31
Total-Onsite
(A1, A2, B1,
B2, B3, C1,
C2, F1, F2)
630,531 14.475 0.167 0.000 0.000 0.000 14 0.099 3%0.20 0.20 0.20 0.25
EXISTING RUNOFF COEFFICIENT CALCULATIONS
Asphalt, Concrete
Rooftop
Gravel
Pavers
The Quarry by Watermark
A.Cvar
May 4, 2021
Project:
Calculations By:
Date:
Character of Surface
Streets, Parking Lots, Roofs, Alleys, and Drives:
Lawns and Landscaping:
Combined Basins
2) Composite Runoff Coefficient adjusted per Table 3.2-3 of the Fort Collins
Stormwater Manual (FCSM).
Lawns, Clayey Soil, Flat Slope < 2%
USDA SOIL TYPE: C
Undeveloped: Greenbelts, Agriculture Composite Runoff Coefficient 2
1) Runoff coefficients per Tables 3.2-1 & 3.2 of the FCSM. Percent impervious per Tables 4.1-2 & 4.1-3 of the FCSM.
Page 1 of 1
Project:
Date:
Where:
Length
(ft)
Elev
Up
Elev
Down
Slope
(%)
Ti
2-Yr
(min)
Ti
10-Yr
(min)
Ti
100-Yr
(min)
Length
(ft)
Elev
Up
Elev
Down
Slope
(%)Surface Roughness
(n)
Flow
Area3
(sq.ft.)
WP
3
(ft)
Hydraulic
Radius (ft)
Velocity
(ft/s)
Tt
(min)
Max.
Tc
(min)
Comp.
Tc 2-Yr
(min)
Tc
2-Yr
(min)
Comp.
Tc 10-Yr
(min)
Tc
10-Yr
(min)
Comp.
Tc 100-Yr
(min)
Tc
100-Yr
(min)
h-a1 H-A1 200 15.34 10.61 2.37%17.9 17.9 16.9 159 10.61 7.95 1.67%Swale (4:1)0.025 4.00 8.25 0.48 4.76 0.56 11.99 18.42 11.99 18.42 11.99 17.43 11.99
h-a2 H-A2 45 15.23 14.59 1.42%10.0 10.0 9.5 N/A Swale (4:1)4.00 8.25 N/A N/A 0.00 10.25 10.04 10.04 10.04 10.04 9.48 9.48
h-b1 H-B1 200 14.80 13.63 0.59%28.5 28.5 26.9 278 13.63 11.74 0.68%Swale (8:1)0.025 8.00 16.12 0.50 3.08 1.50 12.66 29.96 12.66 29.96 12.66 28.38 12.66
h-b2 H-B2 148 17.33 16.31 0.69%23.1 23.1 21.8 365 16.31 13.44 0.79%Swale (8:1)0.025 8.00 16.12 0.50 3.31 1.84 12.85 24.94 12.85 24.94 12.85 23.63 12.85
h-b3 H-B3 52 17.33 16.20 2.17%9.0 9.0 8.4 180 16.20 15.20 0.56%Swale (4:1)0.025 4.00 8.25 0.48 2.74 1.09 11.29 10.11 10.11 10.11 10.11 9.50 9.50
h-c1 H-C1 90 17.23 10.63 7.33%8.2 8.2 7.8 175 10.63 10.10 0.30%Swale (4:1)0.025 4.00 8.25 0.48 2.02 1.44 11.47 9.66 9.66 9.66 9.66 9.20 9.20
h-c2 H-C2 60 17.48 16.29 1.98%10.4 10.4 9.8 826 16.29 13.33 0.36%Swale (8:1)0.025 8.00 16.12 0.50 2.24 6.16 14.92 16.52 14.92 16.52 14.92 15.94 14.92
h-d1 H-D1 60 19.31 17.33 3.30%8.8 8.8 8.3 N/A Swale (4:1)4.00 8.25 N/A N/A 0.00 10.33 8.75 8.75 8.75 8.75 8.26 8.26
h-e1 H-E1 65 17.28 11.43 9.00%6.0 6.0 5.6 1272 11.43 3.16 0.65%Floodplain 0.045 46.50 23.32 1.99 4.23 5.01 17.43 11.05 11.05 11.05 11.05 10.57 10.57
h-e2 H-E2 40 14.10 7.58 16.30%3.8 3.8 3.5 735 7.58 4.17 0.46%Floodplain 0.035 18.00 13.00 1.38 3.60 3.40 14.31 7.23 7.23 7.23 7.23 6.91 6.91
h-f1 H-F1 22 18.47 17.99 2.18%2.9 2.9 1.8 175 17.99 17.00 0.57%Gutter 0.015 3.61 19.18 0.19 2.45 1.19 11.09 4.08 5.00 4.08 5.00 2.94 5.00
h-f2 H-F2 40 20.24 19.49 1.88%4.8 4.8 3.4 570 19.49 16.79 0.47%Gutter 0.015 3.61 19.18 0.19 2.25 4.23 13.39 9.03 9.03 9.03 9.03 7.59 7.59
os1 OS1 30 22.53 21.47 3.53%1.8 1.8 0.7 420 21.47 16.95 1.08%Gutter 0.015 3.61 19.18 0.19 3.39 2.07 12.50 3.88 5.00 3.88 5.00 2.74 5.00
os2 OS2 26 36.00 34.55 5.58%1.0 1.0 0.5 1738 34.55 16.79 1.02%Gutter 0.015 3.61 19.18 0.19 3.30 8.78 19.80 9.80 9.80 9.80 9.80 9.32 9.32
Comb
OS1,
OS2
Comb
OS1,
OS2
26 36.00 34.55 5.58% 5.9 5.9 5.9 1738 34.55 16.79 1.02% Gutter 0.015 3.61 19.18 0.19 3.30 8.78 19.80 14.69 14.69 14.69 14.69 14.69 14.69
os3 OS3 32 20.10 20.05 0.16%16.7 16.7 15.5 615 20.05 12.88 1.17%Gutter 0.015 3.61 19.18 0.19 3.52 2.91 13.59 19.60 13.59 19.60 13.59 18.38 13.59
Total-
Onsite
Total-
Onsite 60 17.48 16.29 1.98% 12.7 12.7 12.7 826 16.29 13.33 0.36% Swale (8:1) 0.025 8.00 16.12 0.50 2.24 6.16 14.92 18.84 14.92 18.84 14.92 18.84 14.92
EXISTING TIME OF CONCENTRATION COMPUTATIONS
Overland Flow, Time of Concentration:
Calculations By:
The Quarry by Watermark
A.Cvar
R = Hydraulic Radius (feet)
S = Longitudinal Slope, feet/feet
Maximum Tc:
Combined Basins
Design
Point Basin
Overland Flow Channelized Flow Time of Concentration
Channelized Flow, Velocity:Channelized Flow, Time of Concentration:
V = Velocity (ft/sec)
n = Roughness Coefficient
May 4, 2021
(Equation 3.3-2 per Fort Collins Stormwater Manual)=1.87 1.1 − ∗
=1.49 ∗
/∗(Equation 5-4 per Fort Collins Stormwater Manual)
=180 + 10
(Equation 3.3-5 per Fort Collins Stormwater Manual)
=∗ 60
(Equation 5-5 per Fort Collins Stormwater Manual)
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.
Page 1 of 1
Tc2 Tc10 Tc100 C2 C10 C100
I2
(in/hr)
I10
(in/hr)
I100
(in/hr)
Q2
(cfs)
Q10
(cfs)
Q100
(cfs)
h-a1 H-A1 1.012 11.99 11.99 11.99 0.20 0.20 0.25 2.09 3.57 7.29 0.4 0.7 1.8
h-a2 H-A2 0.155 10.04 10.04 9.48 0.20 0.20 0.25 2.21 3.78 8.03 0.1 0.1 0.3
h-b1 H-B1 2.525 12.66 12.66 12.66 0.20 0.20 0.25 2.02 3.45 7.04 1.0 1.7 4.4
h-b2 H-B2 3.917 12.85 12.85 12.85 0.20 0.20 0.25 2.02 3.45 7.04 1.6 2.7 7.0
h-b3 H-B3 0.437 10.11 10.11 9.50 0.23 0.23 0.29 2.21 3.78 8.03 0.2 0.4 1.0
h-c1 H-C1 0.739 9.66 9.66 9.20 0.20 0.20 0.25 2.26 3.86 8.03 0.3 0.6 1.5
h-c2 H-C2 5.468 14.92 14.92 14.92 0.20 0.20 0.25 1.90 3.24 6.62 2.1 3.6 9.1
h-d1 H-D1 0.172 8.75 8.75 8.26 0.20 0.20 0.25 2.35 4.02 8.38 0.1 0.1 0.4
h-e1 H-E1 3.384 11.05 11.05 10.57 0.27 0.27 0.33 2.13 3.63 7.57 1.9 3.3 8.6
h-e2 H-E2 1.384 7.23 7.23 6.91 0.28 0.28 0.35 2.52 4.31 9.06 1.0 1.7 4.4
h-f1 H-F1 0.045 5.00 5.00 5.00 0.67 0.67 0.84 2.85 4.87 9.95 0.1 0.1 0.4
h-f2 H-F2 0.177 8.18 8.18 6.74 0.60 0.60 0.75 2.40 4.10 9.06 0.3 0.4 1.2
os1 OS1 0.484 5.00 5.00 5.00 0.83 0.83 1.00 2.85 4.87 9.95 1.1 2.0 4.8
os2 OS2 1.800 8.04 8.04 7.56 0.91 0.91 1.00 2.40 4.10 8.59 3.9 6.7 15.5
Comb OS1, OS2 Comb OS1, OS2 2.284 12.94 12.94 12.94 0.20 0.20 0.25 2.02 3.45 7.04 0.9 1.6 4.0
os3 OS3 0.468 13.59 13.59 13.59 0.25 0.25 0.31 1.95 3.34 6.82 0.2 0.4 1.0
Total-Onsite Total-Onsite 14.475 14.92 14.92 14.92 0.20 0.20 0.20 1.90 3.24 6.62 5.5 9.4 19.2
Design
Point Basin Area
(acres)
Runoff C
Combined Basins
Intensity, I from Fig. 3.4.1 Fort Collins Stormwater Manual
Tc (Min)
EXISTING DIRECT RUNOFF COMPUTATIONS
Intensity Flow
The Quarry by Watermark
A.Cvar
May 4, 2021
Project:
Calculations By:
Date:
Rational Equation: Q = CiA (Equation 6-1 per MHFD)
Page 1 of 1
CHARACTER OF SURFACE1:
Percentage
Impervious
2-yr Runoff
Coefficient
10-yr Runoff
Coefficient
100-yr Runoff
Coefficient
Developed
Asphalt .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100%0.95 0.95 1.19
Concrete .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………100%0.95 0.95 1.19
Rooftop .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………90%0.95 0.95 1.19
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 .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.25 0.25 0.31
Lawns Sandy Soil .…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..……………………………………………….…………………………..………………………………………………2%0.15 0.15 0.19
Notes:
Basin ID Basin Area
(ac)
Area of
Asphalt/Con
crete
(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
A1 1.322 0.036 0.009 0.00 0.00 0.00 1.277 5% 0.27 0.27 0.34
A2 1.750 1.220 0.133 0.00 0.00 0.00 0.397 77% 0.79 0.79 0.99
B1 0.612 0.051 0.152 0.00 0.00 0.00 0.409 32% 0.48 0.48 0.60
B2 0.536 0.248 0.191 0.00 0.00 0.00 0.097 79% 0.82 0.82 1.03
B3 3.484 1.890 0.820 0.00 0.00 0.00 0.774 76% 0.79 0.79 0.99
B4 0.588 0.241 0.022 0.00 0.00 0.00 0.325 45%0.56 0.56 0.70
B5 0.480 0.007 0.269 0.00 0.00 0.00 0.204 53% 0.65 0.65 0.82
B6 1.147 0.666 0.321 0.00 0.00 0.00 0.160 84% 0.85 0.85 1.07
B7 0.490 0.037 0.241 0.00 0.00 0.00 0.212 53% 0.65 0.65 0.81
C1 0.106 0.000 0.000 0.00 0.00 0.00 0.106 2% 0.25 0.25 0.31
C2 0.162 0.007 0.080 0.00 0.00 0.00 0.075 50% 0.63 0.63 0.78
D1 0.979 0.060 0.000 0.00 0.00 0.00 0.919 8% 0.29 0.29 0.37
D2 0.219 0.000 0.000 0.00 0.00 0.00 0.219 2% 0.25 0.25 0.31
D3 0.214 0.104 0.080 0.00 0.00 0.00 0.030 83% 0.85 0.85 1.06
D4 0.768 0.600 0.130 0.00 0.00 0.00 0.038 93% 0.92 0.92 1.14
D5 1.161 0.670 0.300 0.00 0.00 0.00 0.191 81% 0.83 0.83 1.04
D6 0.068 0.009 0.033 0.00 0.00 0.00 0.026 58% 0.68 0.68 0.85
D7 0.639 0.067 0.033 0.00 0.00 0.00 0.539 17% 0.36 0.36 0.45
E1 3.384 0.283 0.270 0.00 0.00 0.00 0.000 16% 0.16 0.16 0.19
E2 1.384 0.143 0.019 0.00 0.00 0.00 0.000 12%0.11 0.11 0.14
F1 0.045 0.028 0.002 0.00 0.00 0.00 0.015 67% 0.72 0.72 0.90
F2 0.177 0.094 0.000 0.00 0.00 0.00 0.083 54% 0.62 0.62 0.78
OS1 0.484 0.407 0.000 0.00 0.00 0.00 0.077 84% 0.84 0.84 1.05
OS2 1.800 1.706 0.000 0.00 0.00 0.00 0.094 95% 0.91 0.91 1.14
OS3 0.873 0.750 0.000 0.00 0.00 0.00 0.123 87% 0.86 0.86 1.07
Detention Pond 1 (B1, B2, B3, B4,
B5, B6, B7)7.337 3.140 2.016 0.000 0.000 0.000 2.181 68% 0.74 0.74 0.93
Detention Pond 2 (OS1, OS2, D1,
D2, D3, D4, D5, D6, D7, F1, F2)7.427 4.495 0.578 0.000 0.000 0.000 2.354 68% 0.73 0.73 0.91
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
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
a1 A1 0.27 0.34 5 5.00%2.0 1.9 570 1.61%0.015 0.59 8.88 1.1 13.2 3.1 2.9 5.0 5.0
a2 A2 0.79 0.99 50 2.00%3.3 1.2 915 0.50%0.015 0.59 4.95 3.1 15.4 6.3 4.2 6.3 5.0
b1 B1 0.48 0.60 240 2.46%13.3 10.7 0 N/A 0.015 N/A N/A N/A 11.3 13.3 10.7 11.3 10.7
b2 B2 0.82 1.03 60 5.00%2.4 0.6 87 1.03%0.015 0.59 7.11 0.2 10.8 2.6 0.8 5.0 5.0
b3 B3 0.79 0.99 130 2.46%4.9 1.7 610 0.79%0.015 0.59 6.20 1.6 14.1 6.5 3.4 6.5 5.0
b4 B4 0.56 0.70 40 2.00%5.1 3.8 162 0.68%0.015 0.59 5.76 0.5 11.1 5.5 4.2 5.5 5.0
b5 B5 0.65 0.82 50 2.80%4.2 2.6 51 1.06%0.038 0.50 2.54 0.3 10.6 4.6 3.0 5.0 5.0
b6 B6 0.85 1.07 96 2.29%3.5 0.4 227 0.97%0.015 0.59 6.88 0.5 11.8 4.0 1.0 5.0 5.0
b7 B7 0.65 0.81 40 3.00%3.7 2.4 291 0.69%0.015 0.59 5.79 0.8 11.8 4.5 3.2 5.0 5.0
c1 C1 0.25 0.31 13 12.85%2.4 2.3 190 0.87%0.038 0.50 2.31 1.4 11.1 3.8 3.6 5.0 5.0
c2 C2 0.63 0.78 40 6.33%3.0 2.0 0 N/A 0.015 n/a N/A N/A 10.2 3.0 2.0 5.0 5.0
d1 D1 0.29 0.37 40 15.03%3.9 3.5 200 0.51%0.015 0.59 4.99 0.7 11.3 4.6 4.2 5.0 5.0
d2 D2 0.25 0.31 100 1.42%14.1 13.1 0 N/A 0.015 n/a N/A N/A 10.6 14.1 13.1 10.6 10.6
d3 D3 0.85 1.06 40 2.57%2.2 0.3 60 0.50%0.015 0.19 2.32 0.4 10.6 2.6 0.8 5.0 5.0
d4 D4 0.92 1.14 82 1.87%2.5 -0.6 185 0.50%0.015 0.19 2.33 1.3 11.5 3.8 0.8 5.0 5.0
d5 D5 0.83 1.04 40 1.00%3.2 0.7 277 0.96%0.015 0.19 3.21 1.4 11.8 4.6 2.1 5.0 5.0
d6 D6 0.68 0.85 40 2.35%3.7 2.2 25 0.68%0.015 0.59 5.76 0.1 10.4 3.8 2.3 5.0 5.0
d7 D7 0.36 0.45 40 3.18%6.0 5.2 280 0.64%0.015 0.59 5.59 0.8 11.8 6.8 6.1 6.8 6.1
e1 E1 0.16 0.19 65 9.00%6.8 6.6 1272 0.65%0.056 1.99 3.39 6.2 17.4 13.1 12.8 13.1 12.8
e2 E2 0.11 0.14 40 16.30%4.6 4.5 735 0.46%0.044 1.38 2.86 4.3 14.3 8.9 8.8 8.9 8.8
f1 F1 0.72 0.90 22 2.18%2.6 1.4 175 0.57%0.015 0.19 2.47 1.2 11.1 3.8 2.5 5.0 5.0
f2 F2 0.62 0.78 40 1.88%4.6 3.1 570 0.47%0.015 0.19 2.26 4.2 13.4 8.8 7.3 8.8 7.3
os1 OS1 0.84 1.05 30 3.53%1.7 0.3 420 1.08%0.015 0.19 3.41 2.1 12.5 3.8 2.4 5.0 5.0
os2 OS2 0.91 1.14 26 5.58%1.0 -0.2 1738 1.02%0.015 0.19 3.32 8.7 19.8 9.8 8.5 9.8 8.5
os3 OS3 0.86 1.07 18 2.06% 1.5 0.2 615 1.38% 0.015 0.19 3.85 2.7 13.5 4.2 2.8 5.0 5.0
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.
Rational Method Equation:
Rainfall Intensity:
a1 A1 1.32 5.0 5.0 0.27 0.34 2.85 4.87 9.95 1.02 1.74 4.47
a2 A2 1.75 5.0 5.0 0.79 0.99 2.85 2.85 9.95 3.94 3.94 17.24
b1 B1 0.61 10.7 10.7 0.48 0.60 2.17 2.17 7.57 0.64 0.64 2.78
b2 B2 0.54 5.0 5.0 0.82 1.03 2.85 2.85 9.95 1.25 1.25 5.49
b3 B3 3.48 5.0 5.0 0.79 0.99 2.85 2.85 9.95 7.84 7.84 34.32
b4 B4 0.59 5.0 5.0 0.56 0.70 2.85 2.85 9.95 0.94 0.94 4.10
b5 B5 0.48 5.0 5.0 0.65 0.82 2.85 2.85 9.95 0.89 0.89 3.92
b6 B6 1.15 5.0 5.0 0.85 1.07 2.85 2.85 9.95 2.78 2.78 12.21
b7 B7 0.49 5.0 5.0 0.65 0.81 2.85 2.85 9.95 0.91 0.91 3.95
c1 C1 0.11 5.0 5.0 0.25 0.31 2.85 2.85 9.95 0.08 0.08 0.33
c2 C2 0.16 5.0 5.0 0.63 0.78 2.85 2.85 9.95 0.29 0.29 1.26
d1 D1 0.98 5.0 5.0 0.29 0.37 2.85 2.85 9.95 0.81 0.81 3.60
d2 D2 0.22 10.6 10.6 0.25 0.31 2.17 2.17 7.57 0.12 0.12 0.51
d3 D3 0.21 5.0 5.0 0.85 1.06 2.85 2.85 9.95 0.52 0.52 2.26
d4 D4 0.77 5.0 5.0 0.92 1.14 2.85 2.85 9.95 2.01 2.01 8.71
d5 D5 1.16 5.0 5.0 0.83 1.04 2.85 2.85 9.95 2.75 2.75 12.01
d6 D6 0.07 5.0 5.0 0.68 0.85 2.85 2.85 9.95 0.13 0.13 0.58
d7 D7 0.64 6.1 6.1 0.36 0.45 2.67 2.67 9.31 0.61 0.61 2.68
e1 E1 3.38 12.8 12.8 0.16 0.19 2.02 2.02 7.04 1.09 1.09 4.53
e2 E2 1.38 8.8 8.8 0.11 0.14 2.35 2.35 8.21 0.36 0.36 1.59
f1 F1 0.05 5.0 5.0 0.72 0.90 2.85 2.85 9.95 0.09 0.09 0.40
f2 F2 0.18 7.3 7.3 0.62 0.78 2.52 2.52 8.80 0.28 0.28 1.21
os1 OS1 0.48 5.0 5.0 0.84 1.05 2.85 2.85 9.95 1.16 1.16 5.06
os2 OS2 1.80 8.5 8.5 0.91 1.14 2.35 2.35 8.21 3.85 3.85 16.84
os3 OS3 0.87 5.0 5.0 0.86 1.07 2.85 2.85 9.95 2.14 2.14 9.29
Intensity,
i2
(in/hr)
Intensity,
i100
(in/hr)
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)
()()()AiCCQf=
NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: THORNBURG HAMILTON FIFTH SUBDIVISION
FORT COLLINS | GREELEY 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 FINAL DRAINAGE REPORT: THORNBURG HAMILTON FIFTH SUBDIVISION
FORT COLLINS | GREELEY APPENDIX
APPENDIX C
WATER QUALITY COMPUTATIONS
The Quarry Calc. By:
Fort Collins, Colorado Date:
372,707 sf
75%
279,530 sf
106,255 sf
211,722 sf
317,977 sf
85.3%
n/a ac-ft
1.90 ac-ft
1.90 ac-ft
Designed Volume 2.10 ac-ft
0.13 ac-ft
0.85 ac-ft
0.98 ac-ft
1.04 ac-ft
05/05/21
Volume Summary Report
Detention Pond 2
Storage and Water Quality Volume
Detention Pond 1
Total Treatment Area
Percent Total Project Area Treated
Required Water Quality Volume
Required Detention Volume
Total Required Volume
Total Required Volume
Required Detention Volume
Designed Volume
Required Water Quality Volume
LID Treatment
C. Ungerman
Rain Garden Treatment Area
Rain Garden
Total Impervious Area
Project Summary
Target Treatment Percentage
Minimum Area to be Treated by LID measures
StormTech Chambers
StormTech Treatment Area
Project:
Location:
Project Number:Project:
Project Location:
Calculations By:Date:
Sq. Ft. Acres
A1 57,578 1.32 5%n/a n/a 0 3,033
A2 76,238 1.75 77%Stormtech 1 Stormtech 1,894 58,703
B1 26,648 0.61 32% Rain Garden A Rain Garden 6,745 8,513
B2 23,356 0.54 79% Rain Garden A Rain Garden 6,745 18,355
B3 151,782 3.48 76% Rain Garden A Rain Garden 6,745 115,150
B4 12,548 0.29 45% Rain Garden A Rain Garden 6,745 5,647
B5 20,910 0.48 53% Rain Garden A Rain Garden 6,745 11,082
B6 49,947 1.15 84% Rain Garden A Rain Garden 6,745 41,739
B7 21,377 0.49 53% Rain Garden A Rain Garden 6,745 11,236
C1 4,634 0.11 2% n/a n/a 0 93
C2 7,076 0.16 50% n/a n/a 0 3,507
D1 42,626 0.98 8% n/a n/a 0 3,414
D2 9,531 0.22 2% n/a n/a 0 191
D3 9,336 0.21 83% n/a n/a 0 7,749
D4 33,439 0.77 93% n/a n/a 0 31,265
D5 50,568 1.16 81% Stormtech 2 Stormtech 1,496 41,113
D6 2,943 0.07 58% Stormtech 2 Stormtech 1,496 1,708
D7 27,830 0.64 17% Stormtech 2 Stormtech 1,496 4,731
F1 1,947 0.04 67% n/a n/a 0 1,305
F2 7,690 0.18 54% n/a n/a 0 4,174
Total 638,004 13.32 372,707
Project Number:Project:
Project Location:
Calculations By:Date:
Sq. Ft. Acres
Rain Garden A 306,568 7.04 69%
B1 Rain Garden 5,621 6,745 211,722
Stormtech 1 76,238 1.75 77%
A2 Stormtech 1,578 1,894 58,703
Stormtech 2 81,341 1.87 58%
D5,6,7 Stormtech 1,247 1,496 47,552
Total 464,147 10.66 10,135 317,977
638,004 ft2
372,707 ft2
54,730 ft2
279,530 ft3
317,977 ft2
85.32%
Total Treated Area
Percent Impervious Treated by LID
A1,C,D1-4,E,F
75% Requried Minium Area to be Treated
LID Site Summary - New Impervious Area
Total Area of Current Development
Total Impervious Area
Total Impervious Area without LID Treatment
Subbasin ID Treatment TypeLID ID Volume per
UD-BMP (ft3)
Area Weighted %
Impervious
1791-001 The Quarry
Fort Collins, Colorado
C. Ungerman 5/5/2021
LID Summary
LID Summary per LID Structure
Impervious
Area (ft2)
Vol. w/20%
Increase per
Fort Collins
Manual (ft3)
LID Summary
AreaBasin ID Treatment TypePercent
Impervious LID ID
The Quarry
5/5/2021
1791-001
Fort Collins, Colorado
C. Ungerman
Total
Impervious
Area (ft2)
Required
Volume (ft3)
LID Summary per Basin
POND 1
Project: The Quarry
By: M. Ruebel
REQUIRED STORAGE & OUTLET WORKS:
BASIN AREA (acres)=1.322 <-- INPUT from impervious calcs
*Basins:A1
BASIN IMPERVIOUSNESS PERCENT =5.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO =0.0500 <-- CALCULATED
Drain Time (hrs)40 <-- INPUT
Drain Time Coefficient 1.0 <-- CALCULATED from Figure Table 3-2
WQCV (watershed inches) =0.036 <-- CALCULATED from Figure 3-2
WQCV (ac-ft) =0.004 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
Adjusted WQCV (cu-ft) =173 <-- CALCULATED
WQ Depth (ft) =4.000 <-- INPUT from stage-storage table
AREA REQUIRED PER ROW, a (in 2) =0.016 <-- CALCULATED from Figure EDB-3
CIRCULAR PERFORATION SIZING:
dia (in) =1/7 <-- INPUT from Figure 5
number of rows =12
t (in) =0.500 <-- INPUT from Figure 5
number of columns =1.000 <-- CALCULATED from WQ Depth and row spacing
WATER QUALITY CONTROL STRUCTURE PLATE
05.05.2021
POND 2
Project: The Quarry
By: M. Ruebel
REQUIRED STORAGE & OUTLET WORKS:
BASIN AREA (acres)=4.470 <-- INPUT from impervious calcs
*Basins:D1,D4,D3,F1,F2, OS1, OS2
BASIN IMPERVIOUSNESS PERCENT =72.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO =0.7200 <-- CALCULATED
Drain Time (hrs)40 <-- INPUT
Drain Time Coefficient 1.0 <-- CALCULATED from Figure Table 5.4-1 (FCSCM)
WQCV (watershed inches) =0.284 <-- CALCULATED from Equation 7-1 (FCSCM)
WQCV (ac-ft) =0.106 <-- CALCULATED from Equation 7-2 (FCSCM)
Adjusted WQCV (ac-ft) =0.127 <-- CALCULATED 120% of WQCV per Section 7.5.4 from FCSCM
WATER QUALITY CONTROL STRUCTURE PLATE
05.04.2021
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia =71.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.710
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.22 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 306,568 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =6,745 cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)DWQCV =12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin =4353 sq ft
D) Actual Flat Surface Area AActual =6250 sq ft
E) Area at Design Depth (Top Surface Area)ATop =7256 sq ft
F) Rain Garden Total Volume VT=6,753 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?1
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y =ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 =cu ft
iii) Orifice Diameter, 3/8" Minimum DO = in
Design Procedure Form: Rain Garden (RG)
M. Ruebel
May 5, 2021
The Quarry
Rain Garden A
UD-BMP (Version 3.07, March 2018)
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
Rain Garden A_UD-BMP_v3.07.xlsm, RG 5/5/2021, 10:21 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
M. Ruebel
May 5, 2021
The Quarry
Rain Garden A
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
Rain Garden A_UD-BMP_v3.07.xlsm, RG 5/5/2021, 10:21 AM
Project Title Date:
Project Number Calcs By:
City
Basins
0.8
WQCV = Watershed inches of Runoff (inches)77%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.248 in
A =1.75 ac
V = 0.0362 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
1894 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
The Quarry May 4, 2021
1791-001 C. Ungerman
Fort Collins
Stormtech Chambers 1 (A2)
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
00.10.20.30.40.50.60.70.80.91WQCV (watershed inches)Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
()iii78.019.10.91aWQCV 23 +-=
()iii78.019.10.91aWQCV 23 +-=
AV*
12
WQCV
=
12 hr
Project Title Date:
Project Number Calcs By:
City
Basins
0.8
WQCV = Watershed inches of Runoff (inches)58%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100)0.184 in
A =1.87 ac
V = 0.0286 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
1496 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
The Quarry May 4, 2021
1791-001 C. Ungerman
Fort Collins
Stormtech Chambers 2 (D5, D6, D7)
0.231
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
00.10.20.30.40.50.60.70.80.91WQCV (watershed inches)Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
()iii78.019.10.91aWQCV 23 +-=
()iii78.019.10.91aWQCV 23 +-=
AV*
12
WQCV
=
12 hr
Vault ID
Total
Required
WQ Volume
(cf)
Flow,
WQ
(cfs)
Chamber
Type
Chamber Release
Ratea
(cfs)
Chamber
Volumeb
(cf)
Installed
Chamber w/
Aggregatec
(cf)
Mimimum
No. of
Chambersd
Total Release
Ratee
(cfs)
Required
Storage
Volume by
FAA Method
(cf)
Mimimum
No. of
Chambersf
Storage
Provided
within the
Chambersg
(cf)
Total
Installed
System
Volumeh
(cf)
Pond1 1894 1.97 SC-740 0.024 45.90 74.90 26 0.61 1313 29 1331 1947
Pond2 1496 0.58 SC-740 0.024 45.90 74.90 20 0.47 1167 26 1193 1498
a. Release rate per chamber, limited by flow through geotextile with accumulated sediment.
b. Volume within chamber only, not accounting for void spaces in surrounding aggregate.
c. Volume includes chamber and void spaces (40%) in surrounding aggregate, per chamber unit.
d. Number of chambers required to provide full WQCV within total installed system, including aggregate.
e. Release rate per chamber times number of chambers.
f. Number of chambers required to provide required FAA storage volume stored within the chamber only (no aggregate storage).
g. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume.
h. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV.
Chamber Configuration Summary
P:\1791-001\Drainage\LID\1791-001 Chamber Summary.xlsx
Chamber Dimensions SC-160 SC-310 SC-740 MC-3500 MC-4500
Width (in)34.0 34.0 51.0 77.0 100.0
Length (in)85.4 85.4 85.4 90.0 52.0
Height (in)16.0 16.0 30.0 45.0 60.0
Floor Area (sf)20.2 20.2 30.2 48.1 36.1
Chamber Volume (cf)6.9 14.7 45.9 109.9 106.5
Chamber/Aggregate Volume (cf)29.3 29.3 74.9 175.0 162.6
Flow Rate* 0.35 gpm/sf
1 cf =7.48052 gal
1 gallon =0.133681 cf
1 GPM = 0.002228 cfs
*Flow rate based on 1/2 of Nov 07 QMAX in Figure 17 of UNH Testing Report
SC-160 SC-310 SC-740 MC-3500 MC-4500
Flow Rate/chamber (cfs) 0.015724 0.015724 0.023586 0.037528 0.028159
end caps have a volume of 108.7 cu. ft.
StormTech Chamber Data
Chamber Flow Rate
Chamber Flow Rate Conversion (gpm/sf to cfs)
end caps have a volume of 45.1 cu. ft.
P:\1791-001\Drainage\LID\1791-001 Chamber Summary.xlsx
NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: THORNBURG HAMILTON FIFTH SUBDIVISION
FORT COLLINS | GREELEY APPENDIX
APPENDIX D
DETENTION POND & SWMM
BBBBBBB BB
B
B
B
B
B BBB BBBB BBBBBBBBBBBBBBBBBB
BB BB BBB
B BBB BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBXXBBBBBBBBBSM1SM2SM2SM1POND 1POND 2S. SHIELDS ST.BASIN A2 AREA EXCLUDEDFROM BASIN SM1 (PER AREA TRADEDISCUSSED IN DRAINAGE REPORT)SWMM EXHIBITFORT COLLINS, COTHE QUARRY BY WATERMARKENGINEERNGIEHTRONRN05.04.21P:\1791-001\DWG\DRNG\1791-001_SWMM.DWG
Project: 1791-001
By: ATC
Date: 05/04/21
Pond ID
Tributary
Area
(Ac)
Ave Percent
Imperviousness
(%)
100-Yr.
Detention Vol.
(Ac-Ft)
Peak Release
(cfs) WQCV (Ac-Ft)
Pond 1 8.51 57 1.82 1.00 n/a
Pond 2 6.33 68 0.86 5.10 0.05
POND SUMMARY TABLE
Project:The Quarry by Watermark
Date:5/4/2021
By:A.Cvar
A C2 C10 C100 Q2 Q10 Q100
(AC)(CFS)(CFS)(CFS)
Total Onsite Basin 14.48 0.20 0.20 0.25 5.49 9.38 19.15
Combined OS1, OS2 2.28 0.20 0.20 0.25 0.92 1.57 4.02
Allowable Release - Onsite Only 5.49 CFS
Allowable Release - Onsite + Offsite Basins OS1, OS2 (Shields R.O.W.)6.41 CFS
Allowable Release Rate Tabulation
Pond Stage-Storage Curve
Pond: 1
Project: 1791-001
By: ATC
Date: 3/1/21
Stage
(FT)
Contour Area
(SF)
Volume
(CU.FT.)
Volume
(AC-FT)
5006.80 2.47 0.00 0.00
5007.00 540.42 38.63 0.00
5007.20 1682.33 250.38 0.01
5007.40 3357.73 744.83 0.02
5007.60 5668.22 1637.40 0.04
5007.80 8663.48 3060.02 0.07
5008.00 12229.92 5139.14 0.12
5008.20 15000.13 7857.43 0.18
5008.40 17067.89 11062.01 0.25
5008.60 18482.35 14616.10 0.34
5008.80 19183.36 18382.45 0.42
5009.00 19807.07 22281.33 0.51
5009.20 20413.20 26303.20 0.60
5009.40 20996.32 30444.02 0.70
5009.60 21565.35 34700.06 0.80
5009.80 22114.54 39067.93 0.90
5010.00 22630.95 43542.38 1.00
5010.20 23367.81 48142.06 1.11
5010.40 24489.98 52927.40 1.22
5010.60 25657.31 57941.67 1.33
5010.80 26634.08 63170.51 1.45
5011.00 27443.71 68578.09 1.57
5011.20 27992.41 74121.61 1.70
5011.40 28545.43 79775.30 1.83
5011.60 29101.90 85539.94 1.96
5011.80 29662.54 91416.30 2.10
Pond Stage-Storage Curve
Pond: 2
Project: 1791-001
By: ATC
Date: 3/1/21
Stage
(FT)
Contour Area
(SF)
Volume
(CU.FT.)
Volume
(AC-FT)
5011.00 13.48 0.00 0.00
5011.20 266.06 22.63 0.00
5011.40 722.70 117.78 0.00
5011.60 1641.13 347.97 0.01
5011.80 2919.21 797.91 0.02
5012.00 4473.39 1531.67 0.04
5012.20 5816.26 2557.70 0.06
5012.40 6984.68 3836.01 0.09
5012.60 8060.75 5339.27 0.12
5012.80 9055.19 7049.90 0.16
5013.00 10006.64 8955.29 0.21
5013.20 10893.75 11044.70 0.25
5013.40 11658.44 13299.48 0.31
5013.60 12380.18 15702.99 0.36
5013.80 13121.41 18252.79 0.42
5014.00 13883.39 20952.91 0.48
5014.20 14668.97 23807.78 0.55
5014.40 15484.34 26822.75 0.62
5014.60 16402.04 30010.94 0.69
5014.80 17338.60 33384.57 0.77
5015.00 18403.47 36958.20 0.85
5015.20 20897.84 40885.74 0.94
5015.40 23715.17 45344.08 1.04
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.014)
--------------------------------------------------------------
*********************************************************
NOTE: The summary statistics displayed in this report are
based on results found at every computational time step,
not just on results from each reporting time step.
*********************************************************
****************
Analysis Options
****************
Flow Units ............... CFS
Process Models:
Rainfall/Runoff ........ YES
RDII ................... NO
Snowmelt ............... NO
Groundwater ............ NO
Flow Routing ........... YES
Ponding Allowed ........ NO
Water Quality .......... NO
Infiltration Method ...... HORTON
Flow Routing Method ...... KINWAVE
Starting Date ............ 11/21/2012 00:00:00
Ending Date .............. 11/22/2012 06:00:00
Antecedent Dry Days ...... 0.0
Report Time Step ......... 00:05:00
Wet Time Step ............ 00:05:00
Dry Time Step ............ 01:00:00
Routing Time Step ........ 30.00 sec
************************** Volume Depth
Runoff Quantity Continuity acre-feet inches
************************** --------- -------
Total Precipitation ...... 4.538 3.669
Evaporation Loss ......... 0.000 0.000
Infiltration Loss ........ 0.857 0.693
Surface Runoff ........... 3.625 2.931
SWMM 5 Page 1
Final Storage ............ 0.077 0.062
Continuity Error (%) ..... -0.474
************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 0.000 0.000
Wet Weather Inflow ....... 3.625 1.181
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.000 0.000
External Inflow .......... 0.000 0.000
External Outflow ......... 3.542 1.154
Flooding Loss ............ 0.000 0.000
Evaporation Loss ......... 0.000 0.000
Exfiltration Loss ........ 0.000 0.000
Initial Stored Volume .... 0.000 0.000
Final Stored Volume ...... 0.090 0.029
Continuity Error (%) ..... -0.173
********************************
Highest Flow Instability Indexes
********************************
Link P_2_O (2)
*************************
Routing Time Step Summary
*************************
Minimum Time Step : 30.00 sec
Average Time Step : 30.00 sec
Maximum Time Step : 30.00 sec
Percent in Steady State : 0.00
Average Iterations per Step : 1.01
Percent Not Converging : 0.00
***************************
Subcatchment Runoff Summary
***************************
SWMM 5 Page 2
------------------------------------------------------------------------------------------------------------------------------
Total Total Total Total Imperv Perv Total Total Peak Runoff
Precip Runon Evap Infil Runoff Runoff Runoff Runoff Runoff Coeff
Subcatchment in in in in in in in 10^6 gal CFS
------------------------------------------------------------------------------------------------------------------------------
SM2 3.67 0.00 0.00 0.58 2.44 0.60 3.04 0.52 35.70 0.829
SM1 3.67 0.00 0.00 0.78 2.05 0.80 2.85 0.66 46.62 0.776
******************
Node Depth Summary
******************
---------------------------------------------------------------------------------
Average Maximum Maximum Time of Max Reported
Depth Depth HGL Occurrence Max Depth
Node Type Feet Feet Feet days hr:min Feet
---------------------------------------------------------------------------------
Node_1 JUNCTION 0.25 0.56 102.06 0 01:59 0.56
Node_2 JUNCTION 0.08 0.51 108.51 0 01:48 0.51
8 JUNCTION 0.01 0.38 115.38 0 00:40 0.37
9 JUNCTION 0.01 0.29 119.29 0 00:40 0.28
Outfall OUTFALL 0.25 0.56 100.56 0 02:00 0.56
POND_2 STORAGE 0.36 3.16 115.16 0 01:48 3.16
POND_1 STORAGE 2.29 3.56 113.56 0 02:43 3.56
*******************
Node Inflow Summary
*******************
-------------------------------------------------------------------------------------------------
Maximum Maximum Lateral Total Flow
Lateral Total Time of Max Inflow Inflow Balance
Inflow Inflow Occurrence Volume Volume Error
Node Type CFS CFS days hr:min 10^6 gal 10^6 gal Percent
-------------------------------------------------------------------------------------------------
Node_1 JUNCTION 0.00 6.10 0 01:59 0 1.15 -0.000
Node_2 JUNCTION 0.00 5.09 0 01:48 0 0.523 0.000
8 JUNCTION 46.62 46.62 0 00:40 0.658 0.658 0.000
SWMM 5 Page 3
9 JUNCTION 35.70 35.70 0 00:40 0.523 0.523 0.000
Outfall OUTFALL 0.00 6.10 0 02:00 0 1.15 0.000
POND_2 STORAGE 0.00 33.23 0 00:43 0 0.524 0.026
POND_1 STORAGE 0.00 42.61 0 00:43 0 0.66 0.009
*********************
Node Flooding Summary
*********************
No nodes were flooded.
**********************
Storage Volume Summary
**********************
--------------------------------------------------------------------------------------------------
Average Avg Evap Exfil Maximum Max Time of Max Maximum
Volume Pcnt Pcnt Pcnt Volume Pcnt Occurrence Outflow
Storage Unit 1000 ft3 Full Loss Loss 1000 ft3 Full days hr:min CFS
--------------------------------------------------------------------------------------------------
POND_2 3.436 1 0 0 37.560 10 0 01:47 5.09
POND_1 37.670 6 0 0 79.147 13 0 02:42 1.03
***********************
Outfall Loading Summary
***********************
-----------------------------------------------------------
Flow Avg Max Total
Freq Flow Flow Volume
Outfall Node Pcnt CFS CFS 10^6 gal
-----------------------------------------------------------
Outfall 98.86 1.44 6.10 1.154
-----------------------------------------------------------
System 98.86 1.44 6.10 1.154
********************
SWMM 5 Page 4
Link Flow Summary
********************
-----------------------------------------------------------------------------
Maximum Time of Max Maximum Max/ Max/
|Flow| Occurrence |Veloc| Full Full
Link Type CFS days hr:min ft/sec Flow Depth
-----------------------------------------------------------------------------
CE_1 CONDUIT 6.10 0 02:00 5.63 0.04 0.14
CE_2 CONDUIT 5.09 0 01:49 5.41 0.04 0.13
9 CONDUIT 42.61 0 00:43 3.60 0.05 0.18
10 CONDUIT 33.23 0 00:43 3.75 0.03 0.14
P_2_O DUMMY 5.09 0 01:48
P_1_O DUMMY 1.03 0 02:43
*************************
Conduit Surcharge Summary
*************************
No conduits were surcharged.
Analysis begun on: Wed May 5 07:50:15 2021
Analysis ended on: Wed May 5 07:50:15 2021
Total elapsed time: < 1 sec
SWMM 5 Page 5
Elapsed Time (hours)
302520151050Total Inflow (CFS)7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
Node Outfall Total Inflow (CFS)
SWMM 5 Page 1
Elapsed Time (hours)
302520151050Flow (CFS)1.2
1.0
0.8
0.6
0.4
0.2
0.0
Link P_1_O Flow (CFS)
SWMM 5 Page 1
Elapsed Time (hours)
302520151050Volume (ft3)80000.0
70000.0
60000.0
50000.0
40000.0
30000.0
20000.0
10000.0
0.0
Node POND_1 Volume (ft3)
SWMM 5 Page 1
Elapsed Time (hours)
302520151050Flow (CFS)6.0
5.0
4.0
3.0
2.0
1.0
0.0
Link P_2_O Flow (CFS)
SWMM 5 Page 1
Elapsed Time (hours)
302520151050Volume (ft3)40000.0
35000.0
30000.0
25000.0
20000.0
15000.0
10000.0
5000.0
0.0
Node POND_2 Volume (ft3)
SWMM 5 Page 1
NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: THORNBURG HAMILTON FIFTH SUBDIVISION
FORT COLLINS | GREELEY APPENDIX
APPENDIX E
EROSION CONTROL REPORT
NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: THORNBURG HAMILTON FIFTH SUBDIVISION
FORT COLLINS | GREELEY EROSION CONTROL REPORT
EROSION CONTROL REPORT
A comprehensive Erosion and Sediment Control Plan (along with associated details) has been included with the
final construction drawings. It should be noted; however, any such Erosion and Sediment Control Plan serves
only as a general guide to the Contractor. Staging and/or phasing of the BMPs depicted, and additional or
different BMPs from those included may be necessary during construction, or as required by the authorities
having jurisdiction.
It shall be the responsibility of the Contractor to ensure erosion control measures are properly maintained and
followed. The Erosion and Sediment Control Plan is intended to be a living document, constantly adapting to
site conditions and needs. The Contractor shall update the location of BMPs as they are installed, removed, or
modified in conjunction with construction activities. It is imperative to appropriately reflect the current site
conditions at all times.
The Erosion and Sediment Control Plan shall address both temporary measures to be implemented during
construction, as well as permanent erosion control protection. Best Management Practices from the Volume 3,
Chapter 7 – Construction BMPs will be utilized. Measures may include, but are not limited to, silt fencing and/or
wattles along the disturbed perimeter, gutter protection in the adjacent roadways, and inlet protection at
existing and proposed storm inlets. Vehicle tracking control pads, spill containment and clean-up procedures,
designated concrete washout areas, dumpsters, and job site restrooms shall also be provided by the Contractor.
Grading and Erosion Control Notes can be found on Sheet CS2 of the Utility Plans. The Final Utility Plans will also
contain a full-size Erosion Control Plan as well as a separate sheet dedicated to Erosion Control Details. In
addition to this report and the referenced plan sheets, the Contractor shall be aware of, and adhere to, the
applicable requirements outlined in any existing Development Agreement(s) of record, as well as the
Development Agreement, to be recorded prior to issuance of the Development Construction Permit. Also, the
Site Contractor for this project may be required to secure a Stormwater Construction General Permit from the
Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division – Stormwater
Program, before commencing any earth disturbing activities. Prior to securing said permit, the Site Contractor
shall develop a comprehensive Storm Water Management Plan (SWMP) pursuant to CDPHE requirements and
guidelines. The SWMP will further describe and document the ongoing activities, inspections, and maintenance
of construction BMPs.
NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: THORNBURG HAMILTON FIFTH SUBDIVISION
FORT COLLINS | GREELEY APPENDIX
APPENDIX F
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, Colorado
The Quarry by Watermark
Natural
Resources
Conservation
Service
November 9, 2020
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......................................................................13
3—Altvan-Satanta loams, 0 to 3 percent slopes.........................................13
4—Altvan-Satanta loams, 3 to 9 percent slopes.........................................15
76—Nunn clay loam, wet, 1 to 3 percent slopes.........................................17
81—Paoli fine sandy loam, 0 to 1 percent slopes.......................................18
Soil Information for All Uses...............................................................................20
Soil Properties and Qualities..............................................................................20
Soil Erosion Factors........................................................................................20
K Factor, Whole Soil....................................................................................20
Soil Qualities and Features.............................................................................23
Hydrologic Soil Group.................................................................................23
References............................................................................................................28
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
44901804490240449030044903604490420449048044905404490180449024044903004490360449042044904804490540491770 491830 491890 491950 492010 492070 492130 492190 492250 492310
491770 491830 491890 491950 492010 492070 492130 492190 492250 492310
40° 33' 56'' N 105° 5' 51'' W40° 33' 56'' N105° 5' 25'' W40° 33' 44'' N
105° 5' 51'' W40° 33' 44'' N
105° 5' 25'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 100 200 400 600
Feet
0 40 80 160 240
Meters
Map Scale: 1:2,760 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 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 15, Jun 9, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 11, 2018—Aug
12, 2018
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
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
3 Altvan-Satanta loams, 0 to 3
percent slopes
18.4 64.3%
4 Altvan-Satanta loams, 3 to 9
percent slopes
1.6 5.5%
76 Nunn clay loam, wet, 1 to 3
percent slopes
6.5 22.7%
81 Paoli fine sandy loam, 0 to 1
percent slopes
2.2 7.5%
Totals for Area of Interest 28.6 100.0%
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.
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.
Custom Soil Resource Report
11
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
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
Custom Soil Resource Report
12
Larimer County Area, Colorado
3—Altvan-Satanta loams, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: jpw2
Elevation: 5,200 to 6,200 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
Altvan and similar soils:45 percent
Satanta and similar soils:30 percent
Minor components:25 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Altvan
Setting
Landform:Benches, terraces
Landform position (three-dimensional):Side slope, tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium
Typical profile
H1 - 0 to 10 inches: loam
H2 - 10 to 18 inches: clay loam, loam, sandy clay loam
H2 - 10 to 18 inches: loam, fine sandy loam, silt loam
H2 - 10 to 18 inches: gravelly sand, gravelly coarse sand, coarse sand
H3 - 18 to 30 inches:
H3 - 18 to 30 inches:
H3 - 18 to 30 inches:
H4 - 30 to 60 inches:
H4 - 30 to 60 inches:
H4 - 30 to 60 inches:
Properties and qualities
Slope:0 to 3 percent
Depth to restrictive feature:More than 80 inches
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 content:10 percent
Available water capacity:Very high (about 13.2 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 3e
Custom Soil Resource Report
13
Hydrologic Soil Group: B
Hydric soil rating: No
Description of Satanta
Setting
Landform:Terraces, structural benches
Landform position (three-dimensional):Side slope, tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium and/or eolian deposits
Typical profile
H1 - 0 to 9 inches: loam
H2 - 9 to 18 inches: loam, clay loam, sandy clay loam
H2 - 9 to 18 inches: loam, clay loam, fine sandy loam
H2 - 9 to 18 inches:
H3 - 18 to 60 inches:
H3 - 18 to 60 inches:
H3 - 18 to 60 inches:
Properties and qualities
Slope:0 to 1 percent
Depth to restrictive feature:More than 80 inches
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 content:10 percent
Available water capacity:Very high (about 27.4 inches)
Interpretive groups
Land capability classification (irrigated): 1
Land capability classification (nonirrigated): 3c
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Nunn
Percent of map unit:10 percent
Hydric soil rating: No
Larim
Percent of map unit:10 percent
Hydric soil rating: No
Stoneham
Percent of map unit:5 percent
Hydric soil rating: No
Custom Soil Resource Report
14
4—Altvan-Satanta loams, 3 to 9 percent slopes
Map Unit Setting
National map unit symbol: jpwf
Elevation: 5,200 to 6,200 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
Altvan and similar soils:55 percent
Satanta and similar soils:35 percent
Minor components:10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Altvan
Setting
Landform:Fans, benches, terraces
Landform position (three-dimensional):Base slope, side slope, tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium
Typical profile
H1 - 0 to 9 inches: loam
H2 - 9 to 16 inches: clay loam, loam, sandy clay loam
H2 - 9 to 16 inches: loam, fine sandy loam, silt loam
H2 - 9 to 16 inches: gravelly sand, gravelly coarse sand, coarse sand
H3 - 16 to 31 inches:
H3 - 16 to 31 inches:
H3 - 16 to 31 inches:
H4 - 31 to 60 inches:
H4 - 31 to 60 inches:
H4 - 31 to 60 inches:
Properties and qualities
Slope:6 to 9 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:10 percent
Custom Soil Resource Report
15
Available water capacity:Very high (about 13.7 inches)
Interpretive groups
Land capability classification (irrigated): 4e
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: B
Hydric soil rating: No
Description of Satanta
Setting
Landform:Structural benches, terraces
Landform position (three-dimensional):Side slope, tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Mixed alluvium and/or eolian deposits
Typical profile
H1 - 0 to 9 inches: loam
H2 - 9 to 14 inches: loam, clay loam, sandy clay loam
H2 - 9 to 14 inches: loam, clay loam, fine sandy loam
H2 - 9 to 14 inches:
H3 - 14 to 60 inches:
H3 - 14 to 60 inches:
H3 - 14 to 60 inches:
Properties and qualities
Slope:3 to 6 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:10 percent
Available water capacity:Very high (about 27.4 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Nunn
Percent of map unit:6 percent
Hydric soil rating: No
Larimer
Percent of map unit:4 percent
Hydric soil rating: No
Custom Soil Resource Report
16
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
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:RareNone
Frequency of ponding:None
Calcium carbonate, maximum content:10 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water capacity:Very high (about 19.8 inches)
Interpretive groups
Land capability classification (irrigated): 2w
Land capability classification (nonirrigated): 3s
Custom Soil Resource Report
17
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
81—Paoli fine sandy loam, 0 to 1 percent slopes
Map Unit Setting
National map unit symbol: jpxx
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
Paoli and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Paoli
Setting
Landform:Stream terraces
Landform position (three-dimensional):Tread
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Alluvium
Typical profile
H1 - 0 to 30 inches: fine sandy loam
H2 - 30 to 60 inches: fine sandy loam, sandy loam, loamy sand
H2 - 30 to 60 inches:
H2 - 30 to 60 inches:
Properties and qualities
Slope:0 to 1 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Custom Soil Resource Report
18
Runoff class: Very 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 content:15 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water capacity:Very high (about 16.5 inches)
Interpretive groups
Land capability classification (irrigated): 1
Land capability classification (nonirrigated): 3c
Hydrologic Soil Group: A
Ecological site: R067BY036CO - Overflow
Hydric soil rating: No
Minor Components
Caruso
Percent of map unit:6 percent
Hydric soil rating: No
Table mountain
Percent of map unit:6 percent
Hydric soil rating: No
Fluvaquentic haplustolls
Percent of map unit:3 percent
Landform:Terraces
Hydric soil rating: Yes
Custom Soil Resource Report
19
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 Erosion Factors
Soil Erosion Factors are soil properties and interpretations used in evaluating the
soil for potential erosion. Example soil erosion factors can include K factor for the
whole soil or on a rock free basis, T factor, wind erodibility group and wind erodibility
index.
K Factor, Whole Soil
Erosion factor K indicates the susceptibility of a soil to sheet and rill erosion by
water. Factor K is one of six factors used in the Universal Soil Loss Equation
(USLE) and the Revised Universal Soil Loss Equation (RUSLE) to predict the
average annual rate of soil loss by sheet and rill erosion in tons per acre per year.
The estimates are based primarily on percentage of silt, sand, and organic matter
and on soil structure and saturated hydraulic conductivity (Ksat). Values of K range
from 0.02 to 0.69. Other factors being equal, the higher the value, the more
susceptible the soil is to sheet and rill erosion by water.
"Erosion factor Kw (whole soil)" indicates the erodibility of the whole soil. The
estimates are modified by the presence of rock fragments.
20
21
Custom Soil Resource Report
Map—K Factor, Whole Soil
44901804490240449030044903604490420449048044905404490180449024044903004490360449042044904804490540491770 491830 491890 491950 492010 492070 492130 492190 492250 492310
491770 491830 491890 491950 492010 492070 492130 492190 492250 492310
40° 33' 56'' N 105° 5' 51'' W40° 33' 56'' N105° 5' 25'' W40° 33' 44'' N
105° 5' 51'' W40° 33' 44'' N
105° 5' 25'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 100 200 400 600
Feet
0 40 80 160 240
Meters
Map Scale: 1:2,760 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
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Soil Rating Lines
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Soil Rating Points
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
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 15, Jun 9, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 11, 2018—Aug
12, 2018
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
22
Table—K Factor, Whole Soil
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
3 Altvan-Satanta loams, 0
to 3 percent slopes
.28 18.4 64.3%
4 Altvan-Satanta loams, 3
to 9 percent slopes
.28 1.6 5.5%
76 Nunn clay loam, wet, 1 to
3 percent slopes
.24 6.5 22.7%
81 Paoli fine sandy loam, 0
to 1 percent slopes
.15 2.2 7.5%
Totals for Area of Interest 28.6 100.0%
Rating Options—K Factor, Whole Soil
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Layer Options (Horizon Aggregation Method): Surface Layer (Not applicable)
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.
Custom Soil Resource Report
23
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.
Custom Soil Resource Report
24
25
Custom Soil Resource Report
Map—Hydrologic Soil Group
44901804490240449030044903604490420449048044905404490180449024044903004490360449042044904804490540491770 491830 491890 491950 492010 492070 492130 492190 492250 492310
491770 491830 491890 491950 492010 492070 492130 492190 492250 492310
40° 33' 56'' N 105° 5' 51'' W40° 33' 56'' N105° 5' 25'' W40° 33' 44'' N
105° 5' 51'' W40° 33' 44'' N
105° 5' 25'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 100 200 400 600
Feet
0 40 80 160 240
Meters
Map Scale: 1:2,760 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
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 15, Jun 9, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Aug 11, 2018—Aug
12, 2018
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
26
Table—Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
3 Altvan-Satanta loams, 0
to 3 percent slopes
B 18.4 64.3%
4 Altvan-Satanta loams, 3
to 9 percent slopes
B 1.6 5.5%
76 Nunn clay loam, wet, 1 to
3 percent slopes
C 6.5 22.7%
81 Paoli fine sandy loam, 0
to 1 percent slopes
A 2.2 7.5%
Totals for Area of Interest 28.6 100.0%
Rating Options—Hydrologic Soil Group
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Custom Soil Resource Report
27
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
28
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
29
NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: THORNBURG HAMILTON FIFTH SUBDIVISION
FORT COLLINS | GREELEY APPENDIX
APPENDIX G
FEMA FIRMETTE
USGS The National Map: Orthoimagery. Data refreshed October, 2020.
National Flood Hazard Layer FIRMette
0 500 1,000 1,500 2,000250
Feet
Ü
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
SPECIAL FLOOD
HAZARD AREAS
Without Base Flood Elevation (BFE)
Zone A, V, A99
With BFE or DepthZone AE, AO, AH, VE, AR
Regulatory Floodway
0.2% Annual Chance Flood Hazard, Areas
of 1% annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mileZone X
Future Conditions 1% Annual
Chance Flood HazardZone X
Area with Reduced Flood Risk due to
Levee. See Notes.Zone X
Area with Flood Risk due to LeveeZone D
NO SCREEN Area of Minimal Flood Hazard Zone X
Area of Undetermined Flood HazardZone 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 map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.
The basemap shown complies with FEMA's basemap
accuracy standards
The flood hazard information is derived directly from the
authoritative NFHL web services provided by FEMA. This map
was exported on 11/9/2020 at 6:04 PM and does not
reflect changes or amendments subsequent to this date and
time. The NFHL and effective information may change or
become superseded by new data over time.
This map image is void if the one or more of the following map
elements do not appear: basemap imagery, flood zone labels,
legend, scale bar, map creation date, community identifiers,
FIRM panel number, and FIRM effective date. Map images for
unmapped and unmodernized areas cannot be used for
regulatory purposes.
Legend
OTHER AREAS OF
FLOOD HAZARD
OTHER AREAS
GENERAL
STRUCTURES
OTHER
FEATURES
MAP PANELS
8
B 20.2
The pin displayed on the map is an approximate
point selected by the user and does not represent
an authoritative property location.
1:6,000
105°5'57"W 40°34'6"N
105°5'20"W 40°33'38"N
NORTHERNENGINEERING.COM | 970.221.4158 FINAL DRAINAGE REPORT: THORNBURG HAMILTON FIFTH SUBDIVISION
FORT COLLINS | GREELEY APPENDIX
MAP POCKET
DR1 – DRAINAGE EXHIBIT
CABLE
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E
E
KEXISTING SIDEWALKEXISTING 8' TRAILCANAL IMPORTATIONWINNE GRANT
R/JOHNELLE S
1821 WALLENBERG
DR
ERIKSEN
CHRISTOPHER M
1825
WALLENBERG
DR
MCCOY JOHN H/SHERRY P
1900 S SHIELDS ST
HILL POND CONDOMINIUMS
FEMA XSEC #22186
5014.4 FT (NAVD 88)
FEMA 100-YR
FLOODWAY
CITY OF FORT
COLLINS 100-YR
FLOODWAY
SheetTHE QUARRY BY WATERMARKThese 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 SETENGINEERNGIEHTRONRNFORT COLLINS: 301 North Howes Street, Suite 100, 80521GREELEY: 820 8th Street, 80631970.221.4158northernengineering.comof 28
LEGEND:
NORTH
( IN FEET )
0
1 INCH = 50 FEET
50 50 100 150
H1 PLANHISTORIC DRAINAGE 25
KEYMAP
CABLE
F.O.
TE
MH
24" SS 24" SS 24" SS 24" SS
24" SS24" SS24" SS24" SS
24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS
EEE
EEEEEEEEE
EEEEE
EEEEE
EEEEE
EEEE
TT
T
T
T
T
T
TTTTTTTTTTTTTTTTTTTTTTT GW W W W W W W W W W W W W W W W W W W W W W W W W W
12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" WEEEEEEEEEEEEEEEEEEEEE
GGGGGGGG
G
G
GG GGGGGGGGGX
X
XXXXX
X
X
XXX
XX
XX
XXXX
X
X
X
X
XXXXXXXX
X
X
X
X
XXX30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" WUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDMH
/ / / / / / / // / / / / / / // / / / / / / /30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W XSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTST
INTERMILL LAND SURVEYING, INC.NORTHERN ENGINEERING SERVICES, INC.
COMPANY PROJECT NO. P-11-6963 COMPANY PROJECT NO. 838-016
DATE: APRIL 2011 DATE: JULY 2015
KING SURVEYORS
COMPANY PROJECT NO. 20190806
DATE: JANUARY 2020
PROJECT DATUM: NAVD88
BENCHMARK 29-92 APPROXIMATE 300 FEET SOUTH OF WEST PROSPECT ROAD AND
SHIELDS STREET, ON THE NORTH END OF THE WEST BRIDGE PARAPET WALL.
ELEVATION: 5025.67
BENCHMARK 28-92 SOUTHWEST CORNER OF WEST PROSPECT ROAD AND CENTER
AVENUE, ON A WATER VALVE PIT.
ELEVATION: 5010.65
PLEASE NOTE: THIS PLAN SET IS USING NAVD88 FOR A VERTICAL DATUM.
SURROUNDING DEVELOPMENTS HAVE USED NGVD29 UNADJUSTED DATUM (PRIOR
CITY OF FORT COLLINS DATUM) FOR THEIR VERTICAL DATUMS.
IF NGVD29 UNADJUSTED DATUM (PRIOR CITY OF FORT COLLINS DATUM) IS REQUIRED
FOR ANY PURPOSE, THE FOLLOWING EQUATION SHOULD BE USED: NGVD29
UNADJUSTED DATUM (PRIOR CITY OF FORT COLLINS DATUM) = NAVD88 - 3.17'.
BASIS OF BEARINGS
WEST LINE OF THE NORTHWEST QUARTER OF SECTION 23 AS BEARING NORTH 00° 01'
50" EAST (ASSUMED BEARING), AND MONUMENTED AS SHOWN ON DRAWING.
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 PLAT FOR LOT AREAS, TRACT SIZES, EASEMENTS, LOT DIMENSIONS,
UTILITY EASEMENTS, OTHER EASEMENTS, AND OTHER SURVEY INFORMATION
2.ALL ELEVATIONS DEPICTED IN PLAN VIEW AND BENCHMARKS LISTED HEREON ARE
PER THE CITY OF FORT COLLINS VERTICAL CONTROL DATUM (NAVD 88).
3.NO STORAGE OF MATERIALS OR EQUIPMENT SHALL BE ALLOWED IN THE FLOODWAY,
WHETHER TEMPORARY (DURING CONSTRUCTION) OR PERMANENT. LANDSCAPING
SHALL ALSO MEET THE REQUIREMENTS FOR NO RISE IN THE FLOODWAY.
4.REFER TO THE PRELIMINARY DRAINAGE AND EROSION CONTROL REPORT FOR THE
QUARRY BY WATERMARK, DATED MAY 5, 2021 BY NORTHERN ENGINEERING FOR
ADDITIONAL INFORMATION.
5.PORTIONS OF THIS PROPERTY ARE LOCATED IN THE CITYREGULATED, 100YEAR
CANAL IMPORTATION FLOODPLAIN/FLOODWAY AS WELL AS THE FEMA REGULATED
SPRING CREEK 100YEAR FLOODPLAIN/FLOODWAY. ANY DEVELOPMENT WITHIN THE
FLOODPLAIN MUST COMPLY WITH THE SAFETY REGULATIONS OF CHAPTER 10 OF CITY
MUNICIPAL CODE. THE DEVELOPER SHALL OBTAIN A FLOODPLAIN USE PERMIT FROM
THE CITY OF FORT COLLINS AND PAY ALL APPLICABLE FLOODPLAIN USE PERMIT FEES
PRIOR TO COMMENCING ANY CONSTRUCTION ACTIVITY (BUILDING OF STRUCTURES,
GRADING, FILL, DETENTION PONDS, BIKE PATHS, PARKING LOTS, UTILITIES,
LANDSCAPED AREAS, FLOOD CONTROL CHANNELS, ETC.) WITHIN THE CITY OF FORT
COLLINS FLOODPLAIN LIMITS AS DELINEATED ON THE FINAL SUBDIVISION PLAT
6.ANY CONSTRUCTION ACTIVITIES, NONSTRUCTURAL DEVELOPMENT (BRIDGES,
SIDEWALKS, CULVERTS, VEGETATION, CURBCUTS, GRADING, ETC.) IN THE
REGULATORY FLOODWAY MUST BE PRECEDED BY A NORISE CERTIFICATION, WHICH
MUST BE PREPARED BY A PROFESSIONAL ENGINEER LICENSED IN THE STATE OF
COLORADO.
7.NO STORAGE OF MATERIALS OR EQUIPMENT SHALL BE ALLOWED IN THE FLOODWAY,
WHETHER TEMPORARY (DURING CONSTRUCTION) OR PERMANENT.
8.ANY PEDESTRIAN BRIDGES IN THE FLOODWAY THAT ARE NOT ABLE TO PASS THE 100
YEAR FLOW ARE REQUIRED TO BE “BREAKAWAY” AND TETHERED.
A
CROSS-SECTION (CSL)XS#: 2446
FIELD SURVEY BY:
CORRECTED EFFECTIVE BASE FLOOD
ELEVATION (BFE)
5003 (NAVD88)ELEVATION NAVD 88
BENCHMARK
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
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
DateCity Engineer
Date
Date
Date
Date
Stormwater Utility
Parks & Recreation
Traffic Engineer
Date
APPROVED:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Water & Wastewater Utility
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Environmental Planner
CABLE
F.O.
T
MH
B M
TTTTTTA
M
AL179
178
177
176
175
174
173
172171170169168/ / / / / / / // / / / / / / /
W WWWSS
SSUDUDS
S
D
F.O.
D
MH
MM
MH
/ / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / // / / / / / / /STSTSTSTSSSSSSSSSSUDUDUD
FDC
FDC FDCFDCFDC FDC
FDC
FDC / / / / / / / // / / / / / / /
W WWWSS
SSUDUDBBBBBBBBBBBBB BBBBBBBBBBBBBBBBBBBBBBBBBBBBB BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBXXXXBBBBBBBBBFollow-up on offsite basin flows in SWMM Model
TRACT B
TRACT A
RAIN GARDEN A
EXISTING DRAINAGE
DITCH (DITCH C)
DETENTION
POND 2
1.32 ac.
A1
0.98 ac.
D1
0.22 ac.
D2
0.61 ac.
B1
1.75 ac.
A2
0.54 ac.
B2
0.64 ac.
D7
1.15 ac.
B6
0.48 ac.
B5
0.29 ac.
B4
3.48 ac.
B3
0.11 ac.
C1
0.16 ac.
C2
0.49 ac.
B7
0.47 ac.
OS3
3.38 ac.
E1
1.38 ac.
E2
0.48 ac.
OS1
1.80 ac.
OS2
0.18 ac.
F2
0.04 ac.
F1
d7
d1
a1
b1
b2
b4
b5
b6
b7
b3
c1
d2
os2
os3
e1
e2
os1
c2
CITY OF FORT COLLINS
100-YR FLOODWAY
S SHIELDS ST.HOBBIT ST.WALLENBERG DR.FEMA 100-YR
HIGH RISK
FLOOD FRINGE
CITY OF FORT COLLINS
100-YR FLOODPLAIN
EXIST
I
N
G
S
P
R
I
N
G
C
R
E
E
K
T
R
A
I
L
SPRI
N
G
C
R
E
E
KEXISTING SIDEWALKCANAL IMPORTATIONWINNE GRANT R/JOHNELLE S
1821 WALLENBERG DR
ERIKSEN CHRISTOPHER M
1825 WALLENBERG DR
MCCOY JOHN H/SHERRY P
1900 S SHIELDS ST
HILL POND CONDOMINIUMS
f2
f1
PROPOSED
STORM DRAIN
PROPOSED
STORM DRAIN
PROPOSED
STORM DRAIN
PROPOSED
OUTFALL PIPE
PROPOSED
STORM DRAIN
PROPOSED OUTLET
STRUCTURE 5:15:15:15:112:1a2
PROPOSED
STORM DRAIN
DETENTION
POND 1
1.16 ac.
D5
PROPOSED
STORM DRAIN
PROPOSED
STORM DRAIN 0.21 ac.
D3
0.77 ac.
D4
0.07 ac.
D6
d4
d3
d5
d6
PROPOSED OUTLET
STRUCTURE
PROPOSED
STORM
CHAMBERS
PROPOSED
STORM
CHAMBERSFEMA XSEC #22186
5014.4 FT (NAVD 88)
FEMA 100-YR
FLOODWAY
CITY OF FORT
COLLINS 100-YR
FLOODWAY
PROPOSED
STORM DRAIN
PROPOSED
STORM DRAIN
BUILDING 1 BUILDING 2
BUILDING 3
BUILDING 4
BUILDING 5 BUILDING 6 BUILDING 7
BUILDING 1
BUILDING 2
BUILDING 3
BUILDING 4
BUILDING 5
BUILDING 6
BUILDING 7
BUILDING 8
BUILDING 9
BUILDING 10
POND
OVERFLOW PATH
POND
OVERFLOW PATH EXISTING 8' TRAILW PROSPECT RD.
W STUART ST.
INTERMILL LAND SURVEYING, INC.NORTHERN ENGINEERING SERVICES, INC.
COMPANY PROJECT NO. P-11-6963 COMPANY PROJECT NO. 838-016
DATE: APRIL 2011 DATE: JULY 2015
KING SURVEYORS
COMPANY PROJECT NO. 20190806
DATE: JANUARY 2020
PROJECT DATUM: NAVD88
BENCHMARK 29-92 APPROXIMATE 300 FEET SOUTH OF WEST PROSPECT ROAD AND
SHIELDS STREET, ON THE NORTH END OF THE WEST BRIDGE PARAPET WALL.
ELEVATION: 5025.67
BENCHMARK 28-92 SOUTHWEST CORNER OF WEST PROSPECT ROAD AND CENTER
AVENUE, ON A WATER VALVE PIT.
ELEVATION: 5010.65
PLEASE NOTE: THIS PLAN SET IS USING NAVD88 FOR A VERTICAL DATUM.
SURROUNDING DEVELOPMENTS HAVE USED NGVD29 UNADJUSTED DATUM (PRIOR
CITY OF FORT COLLINS DATUM) FOR THEIR VERTICAL DATUMS.
IF NGVD29 UNADJUSTED DATUM (PRIOR CITY OF FORT COLLINS DATUM) IS REQUIRED
FOR ANY PURPOSE, THE FOLLOWING EQUATION SHOULD BE USED: NGVD29
UNADJUSTED DATUM (PRIOR CITY OF FORT COLLINS DATUM) = NAVD88 - 3.17'.
BASIS OF BEARINGS
WEST LINE OF THE NORTHWEST QUARTER OF SECTION 23 AS BEARING NORTH 00° 01'
50" EAST (ASSUMED BEARING), AND MONUMENTED AS SHOWN ON DRAWING.
SheetTHE QUARRY BY WATERMARKThese 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 SETENGINEERNGIEHTRONRNFORT COLLINS: 301 North Howes Street, Suite 100, 80521GREELEY: 820 8th Street, 80631970.221.4158northernengineering.comof 28
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:
A
LEGEND:
NORTH
( IN FEET )
0
1 INCH = 80 FEET
80 80 160 240
DR1 DRAINAGE PLAN26
KEYMAP
CABLE
F.O.
TE
MH
24" SS 24" SS 24" SS 24" SS
24" SS24" SS24" SS24" SS
24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS 24" SS
EEE
EEEEEEEEE
EEEEE
EEEEE
EEEEE
EEEE
TT
T
T
T
T
T
TTTTTTTTTTTTTTTTTTTTTTT GW W W W W W W W W W W W W W W W W W W W W W W W W W
12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" W12" WEEEEEEEEEEEEEEEEEEEEE
GGGGGGGG
G
G
GG GGGGGGGGGX
X
XXXXX
X
X
XXX
XX
XX
XXXX
X
X
X
X
XXXXXXXX
X
X
X
X
XXX30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" W30" WUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDUDMH
/ / / / / / / // / / / / / / // / / / / / / /30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W 30" W XSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTSTST
CROSS-SECTION (CSL)XS#: 2446
FIELD SURVEY BY:
CORRECTED EFFECTIVE BASE FLOOD
ELEVATION (BFE)
5003 (NAVD88)ELEVATION NAVD 88
BENCHMARK
1.REFER TO THE PLAT FOR LOT AREAS, TRACT SIZES, EASEMENTS, LOT DIMENSIONS,
UTILITY EASEMENTS, OTHER EASEMENTS, AND OTHER SURVEY INFORMATION
2.ALL ELEVATIONS DEPICTED IN PLAN VIEW AND BENCHMARKS LISTED HEREON ARE
PER THE CITY OF FORT COLLINS VERTICAL CONTROL DATUM (NAVD 88).
3.NO STORAGE OF MATERIALS OR EQUIPMENT SHALL BE ALLOWED IN THE FLOODWAY,
WHETHER TEMPORARY (DURING CONSTRUCTION) OR PERMANENT. LANDSCAPING
SHALL ALSO MEET THE REQUIREMENTS FOR NO RISE IN THE FLOODWAY.
4.REFER TO THE PRELIMINARY DRAINAGE AND EROSION CONTROL REPORT FOR THE
QUARRY BY WATERMARK, DATED MAY 5, 2021 BY NORTHERN ENGINEERING FOR
ADDITIONAL INFORMATION.
5.PORTIONS OF THIS PROPERTY ARE LOCATED IN THE CITYREGULATED, 100YEAR
CANAL IMPORTATION FLOODPLAIN/FLOODWAY AS WELL AS THE FEMA REGULATED
SPRING CREEK 100YEAR FLOODPLAIN/FLOODWAY. ANY DEVELOPMENT WITHIN THE
FLOODPLAIN MUST COMPLY WITH THE SAFETY REGULATIONS OF CHAPTER 10 OF CITY
MUNICIPAL CODE. THE DEVELOPER SHALL OBTAIN A FLOODPLAIN USE PERMIT FROM
THE CITY OF FORT COLLINS AND PAY ALL APPLICABLE FLOODPLAIN USE PERMIT FEES
PRIOR TO COMMENCING ANY CONSTRUCTION ACTIVITY (BUILDING OF STRUCTURES,
GRADING, FILL, DETENTION PONDS, BIKE PATHS, PARKING LOTS, UTILITIES,
LANDSCAPED AREAS, FLOOD CONTROL CHANNELS, ETC.) WITHIN THE CITY OF FORT
COLLINS FLOODPLAIN LIMITS AS DELINEATED ON THE FINAL SUBDIVISION PLAT
6.ANY CONSTRUCTION ACTIVITIES, NONSTRUCTURAL DEVELOPMENT (BRIDGES,
SIDEWALKS, CULVERTS, VEGETATION, CURBCUTS, GRADING, ETC.) IN THE
REGULATORY FLOODWAY MUST BE PRECEDED BY A NORISE CERTIFICATION, WHICH
MUST BE PREPARED BY A PROFESSIONAL ENGINEER LICENSED IN THE STATE OF
COLORADO.
7.NO STORAGE OF MATERIALS OR EQUIPMENT SHALL BE ALLOWED IN THE FLOODWAY,
WHETHER TEMPORARY (DURING CONSTRUCTION) OR PERMANENT.
8.ANY PEDESTRIAN BRIDGES IN THE FLOODWAY THAT ARE NOT ABLE TO PASS THE 100
YEAR FLOW ARE REQUIRED TO BE “BREAKAWAY” AND TETHERED.
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
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
DEVELOPED DRAINAGE SUMMARY
Design
Point Basin ID
Total
Area
(acres)
C2 C100 2-Yr Tc
(min)
100-Yr Tc
(min)
Q2
(cfs)
Q100
(cfs)
a1 A1 1.322 0.23 0.28 12.90 12.90 0.60 2.62
a2 A2 1.750 0.78 0.97 15.36 15.36 2.55 11.12
b1 B1 0.612 0.45 0.56 11.33 11.33 0.58 2.54
b2 B2 0.536 0.81 1.00 5.00 5.00 1.24 5.33
b3 B3 3.484 0.78 0.98 14.11 14.11 5.24 22.89
b4 B4 0.288 0.88 1.00 6.73 6.73 0.66 2.77
b5 B5 0.480 0.63 0.79 7.72 7.72 0.74 3.52