HomeMy WebLinkAboutSALUD FAMILY HEALTH CENTER - PDP - PDP160015 - REPORTS - DRAINAGE REPORTOctober 12, 2016
PRELIMINARY DRAINAGE AND
EROSION CONTROL REPORT FOR
SALUD FAMILY HEALTH CENTER
Fort Collins, Colorado
Prepared for:
Salud Family Health Centers
203 S. Rollie Ave.
Fort Lupton, CO 80621
Prepared by:
301 N. Howes, Suite 100
Fort Collins, Colorado 80521
Phone: 970.221.4158 Fax: 970.221.4159
www.northernengineering.com
Project Number: 1067-001
This Drainage Report is consciously provided as a PDF.
Please consider the environment before printing this document in its entirety.
When a hard copy is absolutely necessary, we recommend double-sided printing.
October 12, 2016
City of Fort Collins
Stormwater Utility
700 Wood Street
Fort Collins, Colorado 80521
RE: Preliminary Drainage and Erosion Control Report for
SALUD FAMILY HEALTH CENTER
Dear Staff:
Northern Engineering is pleased to submit this Preliminary Drainage and Erosion Control Report
for your review. This report accompanies the Project Development Plan submittal for the
proposed Salud Family Health Ceter development.
This report has been prepared in accordance to Fort Collins Stormwater Criteria Manual (FCSCM),
and serves to document the stormwater impacts associated with the proposed project. We
understand that review by the City 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.
Aaron Cvar, PhD, PE
Senior Project Engineer
Salud Family Health Center
Preliminary Drainage Report
TABLE OF CONTENTS
I. GENERAL LOCATION AND DESCRIPTION ................................................................... 1
A. Location ............................................................................................................................................. 1
B. Description of Property ..................................................................................................................... 2
C. Floodplain.......................................................................................................................................... 3
II. DRAINAGE BASINS AND SUB-BASINS ....................................................................... 4
A. Major Basin Description .................................................................................................................... 4
B. Sub-Basin Description ....................................................................................................................... 5
III. DRAINAGE DESIGN CRITERIA ................................................................................... 5
A. Regulations........................................................................................................................................ 5
B. Four Step Process .............................................................................................................................. 5
C. Development Criteria Reference and Constraints ............................................................................ 6
D. Hydrological Criteria ......................................................................................................................... 6
E. Hydraulic Criteria .............................................................................................................................. 6
F. Modifications of Criteria ................................................................................................................... 6
IV. DRAINAGE FACILITY DESIGN .................................................................................... 7
A. General Concept ............................................................................................................................... 7
B. Specific Details .................................................................................................................................. 8
V. CONCLUSIONS ........................................................................................................ 9
A. Compliance with Standards .............................................................................................................. 9
B. Drainage Concept .............................................................................................................................. 9
APPENDICES:
APPENDIX A – Hydrologic Computations
APPENDIX B - USDA Soils Information
APPENDIX C – SWMM Modeling; Detention Computations
APPENDIX D – LID/Water Quality Treatment Information
APPENDIX E – Erosion Control Report
Salud Family Health Center
Preliminary Drainage Report
LIST OF FIGURES:
Figure 1 – Aerial Photograph ................................................................................................ 2
Figure 2– Proposed Site Plan ................................................................................................ 3
Figure 3 – Existing Floodplains ............................................................................................. 4
MAP POCKET:
Proposed Drainage Exhibit
Salud Family Health Center
Preliminary Drainage Report 1
I. GENERAL LOCATION AND DESCRIPTION
A. Location
1. Vicinity Map
2. The project site is located in the northwest quarter of Section 10, Township 7 North,
Range 69 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer,
State of Colorado.
3. The project site is located just east of the intersection of Laporte Ave. and North Taft
Hill Rd.
4. The proposed development site is in the City of Fort Collins West Vine Master Basin.
Detention requirements for this basin are to detain the difference between the 100-
year developed inflow rate and the historic 2-year release rate. However, due to site
constraints, the proposed drainage concept for the site is to place an interim pumped
detention pond in the northwest corner of Lot 6.
5. The pumped detention pond is to be located so that in the future a gravity tie-in to a
future City of Fort Collins Regional Pond, which is anticipated to be constructed just
northwest of the project site. A rough anticipated construction date for this pond is
the year 2025. In the interim period, the onsite detention pond will be pumped. The
Salud Family Health Center
Preliminary Drainage Report 2
pump will be sized to discharge at a rate that adequately evacuates all storm runoff
from the pond to meet State of Colorado revised Statute 37-92-602(8). This states
that 97% of all the stormwater runoff from a 5-year or less event be released within
72 hours of the storm event, and 99% of all of the stormwater runoff from greater
than a 5-year event be released within 120 hours of the storm event. Water quality
treatment methods are proposed for the site, and are described in further detail
below.
6. As this is an infill site, much of the area surrounding the site is fully developed.
7. A small amount of offsite flows enter the site from the east. Offsite runoff peak flow
rates have been calculated and are provided in Appendix A.
B. Description of Property
1. The development area is roughly 22.7 net acres.
Figure 1 – Aerial Photograph
2. The subject property is currently composed of existing buildings, and landscaped
areas. Existing ground slopes are mild to moderate (i.e., 1 - 6±%) through the
interior of the property. General topography slopes from south to north; however, the
front portion of the property has an existing parking lot that slopes from north to
south, towards Laporte Avenue.
3. 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 of Nunn Clay Loam, and Fort Collins Loam which fall into Hydrologic
SITE
Salud Family Health Center
Preliminary Drainage Report 3
Soil Group C.
4. The proposed project site plan is composed of the development of a medical building,
associated parking and extension of a public roadway which will serve as access to
the building and parking areas. Associated site work, water, and sewer lines will be
constructed with the development. Onsite detention and water quality treatment is
proposed and will consist of several features which are discussed in Section IV,
below.
Figure 2– Proposed Site Plan
5. There are no known irrigation laterals crossing the site.
6. The proposed land use is commercial.
C. Floodplain
1. The project site is encroached by a City of Fort Collins designated floodplain (West
Vine 100-year floodplain and floodway). No FEMA 100-year floodplains encroach the
site.
2. It is noted that the West Vine floodplain spill from the Larimer Canal No. 2 irrigation
Salud Family Health Center
Preliminary Drainage Report 4
ditch enters the project site; however, current floodplain mapping changes are under
way by the City of Fort Collins, and we are working with City Stormwater Utility Staff
and the owning entity of the Larimer No. 2 to incorporate the changes regarding this
spill from the Larimer No. 2. We are currently working with the City on the modeling
of the spill from the ditch and are in process with the design of a side spill weir and
grading within the project site to allow for this spill to safely pass along the western
perimeter of the site (just west of the large existing building that is to remain and to
be renovated). We have also discussed the construction of this side spill weir with
the Larimer No. 2 and have had a favorable response. We will submit side spill weir
plans to both the City and the Larimer No. 2 at Final design.
3. A separate Floodplain Modeling Report will be submitted to address proposed
changes to the current floodplain and floodway through the site which will incorporate
the side spill weir and grading within the site.
Figure 3 –Current City of Fort Collins Floodplain Mapping
II. DRAINAGE BASINS AND SUB-BASINS
A. Major Basin Description
1. The proposed development site is in the City of Fort Collins West Vine Master Basin.
Detention requirements for this basin are to detain the difference between the 100-
year developed inflow rate and the historic 2-year release rate. However, due to site
constraints, the proposed drainage concept for the site is to place an interim pumped
detention pond in the northwest corner of Lot 6.
SITE
Salud Family Health Center
Preliminary Drainage Report 5
B. Sub-Basin Description
1. The overall subject property historically drains overland from south to north.
However, the front portion of the property has an existing parking lot that slopes from
north to south, towards Laporte Avenue.
2. A more detailed description of the project drainage patterns is provided below.
III. DRAINAGE DESIGN CRITERIA
A. Regulations
There are no optional provisions outside of the FCSCM proposed with the proposed
project.
B. Four Step Process
The overall stormwater management strategy employed with the proposed project 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
Several techniques have been utilized with the proposed development to facilitate the
reduction of runoff peaks, volumes, and pollutant loads as the site is developed from the
current use by implementing multiple Low Impact Development (LID) strategies including:
Conserving existing amenities in the site including the existing vegetated areas.
Providing vegetated open areas throughout the site to reduce the overall impervious
area and to minimize directly connected impervious areas (MDCIA).
Routing flows, to the extent feasible, through vegetated swales to increase time of
concentration, promote infiltration and provide initial water quality.
Step 2 – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with
Slow Release
The efforts taken in Step 1 will facilitate the reduction of runoff; however, urban
development of this intensity will still generate stormwater runoff that will require
additional BMPs and water quality. The majority of stormwater runoff from the site will
ultimately be intercepted and treated using detention and LID treatment methods prior to
exiting the site.
Step 3 – Stabilize Drainageways
There are no major drainageways within the subject property. While this step may not
seem applicable to proposed development, the project indirectly helps achieve stabilized
drainageways nonetheless. By providing water quality treatment, where none previously
existed, sediment with erosion potential is removed from downstream drainageway
systems. Furthermore, this project will pay one-time stormwater development fees, as
well as ongoing monthly stormwater utility fees, both of which help achieve City-wide
drainageway stability.
Step 4 – Implement Site Specific and Other Source Control BMPs.
The proposed project will improve upon site specific source controls compared to historic
conditions:
Salud Family Health Center
Preliminary Drainage Report 6
The proposed development will provide LID and water quality treatment; thus,
eliminating sources of potential pollution previously left exposed to weathering and
runoff processes.
C. Development Criteria Reference and Constraints
The subject property is surrounded by currently developed properties. Thus, several
constraints have been identified during the course of this analysis that will impact the
proposed drainage system including:
Existing elevations along the property lines will generally be maintained.
As previously mentioned, overall drainage patterns of the existing site will be
maintained.
Elevations of existing downstream facilities that the subject property will release to
will be maintained.
D. Hydrological Criteria
1. The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in
Figure RA-16 of the FCSCM, serve as the source for all hydrologic computations
associated with the proposed development. Tabulated data contained in Table RA-7
has been utilized for Rational Method runoff calculations.
2. The Rational Method has been employed to compute stormwater runoff utilizing
coefficients contained in Tables RO-11 and RO-12 of the FCSCM.
3. Three separate design storms have been utilized to address distinct drainage
scenarios. A fourth design storm has also been computed for comparison purposes.
The first design storm considered is the 80th percentile rain event, which has been
employed to design the project’s water quality features. The second event analyzed is
the “Minor,” or “Initial” Storm, which has a 2-year recurrence interval. The third
event considered is the “Major Storm,” which has a 100-year recurrence interval.
The fourth storm computed, for comparison purposes only, is the 10-year event.
4. No other assumptions or calculation methods have been used with this development
that are not referenced by current City of Fort Collins criteria.
E. Hydraulic Criteria
1. As previously noted, the subject property maintains historic drainage patterns.
2. All drainage facilities proposed with the project are designed in accordance with
criteria outlined in the FCSCM and/or the Urban Drainage and Flood Control District
(UDFCD) Urban Storm Drainage Criteria Manual.
3. As stated above, the subject property is located in a City designated floodplain. The
proposed project does not propose to modify any natural drainageways.
F. Modifications of Criteria
1. The proposed development is not requesting any modifications to criteria at this time.
Salud Family Health Center
Preliminary Drainage Report 7
IV. DRAINAGE FACILITY DESIGN
A. General Concept
1. The main objectives of the project drainage design are to maintain existing drainage
patterns, and to ensure no adverse impacts to any adjacent properties.
2. LID will be provided in a forebay upstream of the proposed detention pond. Water
quality capture volume will be provided in the lower stage of the detention pond.
Forebay volume and water quality capture volume computations are provided in
Appendix D.
3. Drainage patterns anticipated for drainage basins shown in the Drainage Exhibit are
described below. Drainage basins have been defined for preliminary design purposes
and are subject to change at Final design; however, general drainage patterns and
concepts are not expected to be significantly altered.
Basins 1 and 2
Basins 1 and 2 are composed of the current development areas which include
renovation of the existing building, proposed parking areas, landscaped areas and the
proposed Pond 1. Basin 1 is composed primarily of landscaped areas and Pond 1,
and runoff will generally sheet flow into Pond 1. Runoff from Basin 2 will be
conveyed into the proposed LID forebay prior to discharge into Pond 1 via proposed
parking lot curb and gutter, inlets and storm system as shown on the Drainage Exhibit.
Basin 3
Basin 3 is composed of primarily of undeveloped area landscaped areas, and runoff
will generally sheet flow into north to adjacent offsite land. We are not increasing land
slope or drainage area, and are not concentrating flow within this basin; therefore
increase in runoff to offsite properties will be experienced.
Basins 4 and 7
Basins 4 and 7 are anticipated to be developed in the future. A future LID feature and
detention pond is to be provided within Basin 7 which will detain and release into the
currently proposed storm line running from this basin into proposed Pond 1. Basin 4,
however, has been accounted for in the design of the proposed Pond 1 at the
northwest corner of the site, and future development of this basin will only need to
create some form of acceptable LID at such time as the basin develops. Also, when
this basin develops, conveyance will need to be constructed from the basin into the
Pond 1.
Basins 5, 6, and 9
Basins 5, 6, and 9 are anticipated to be developed in the future. General drainage
patterns, based on existing topography are from south to north, into the Larimer Canal
No. 2 irrigation ditch. These future development sites will be required to meet all City
and Ditch standards when developed. We anticipate that these sites will need to
detain flows as well as provide water quality treatment prior to discharge into the
Larimer Canal No. 2. We are showing a “future” LID feature and detention pond on
the Drainage Exhibit within Basin 5 and Basin 9 as a placeholder for LID and
detention. We anticipate that in the future the LID feature and pond shown in Basin 5
will treat and detain runoff from Basins 5 and 6, and the LID feature and pond shown
in Basin 9 will treat and detain runoff from Basin 9. It is noted, however, at which
Salud Family Health Center
Preliminary Drainage Report 8
time the development occurs, current detention and water quality standards at the
time of development will apply.
Basins 8
Basin 8 is composed of dedicated Right of Way that will serve as access for the
proposed parking area and building in Basin 2. A portion of this Right of Way that will
connect in the future along the site eastern boundary (Please see Drainage Exhibit)
has been included in runoff computations for this basin, although only part of the
roadway is to be constructed with the current phase of development. Runoff from this
basin will be conveyed via curb and gutter to a storm system, and then into the
proposed LID forebay prior to discharge into proposed Pond 1, as shown on the
Drainage Exhibit.
Basin 10
Area within Basin 10 is currently is composed of an existing parking lot and
landscaped area, and historically drains south into Laporte Avenue. We anticipate
future development of this area to maintain this drainage pattern and to simply be a
repair or overlay of the existing parking lot. We understand that currently, in such a
case, as long as imperviousness does not increase from historic conditions, detention
would not be required, and we have noted the historic drainage quantity on the
Drainage Exhibit. However, at which time development occurs, current City standards
will apply.
Basin OS1
Basin OS1 consists primarily of offsite area to the east of the site which historically
drains across the project site. This offsite drainage will be accounted for at Final, and
the proposed storm system will be designed to safely pass100-year flows from this
offsite area.
A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of
this report.
B. Specific Details
1. A detention basin is proposed in the west portion of the site and will detain up
to the 100-year storm event and release at or below the allowable (for West
Vine Basin) 2-year historic runoff rate calculated as 0.31 cfs per acre (Please
see calculations provided in Appendix A). A lowered release rate is
anticipated, as the release from the pond will be pumped. The pump will be
sized to discharge at a rate of 0.60 cfs based on current preliminary design,
requiring a 100-year detention volume of 3.52 acre-feet. This release rate has
been determined in order that both Pond 1 and a future interconnected Pond
2, as shown on the Drainage Exhibit will adequately evacuate all storm runoff
from the interconnected pond system to meet State of Colorado revised Statute
37-92-602(8). This states that 97% of all the stormwater runoff from a 5-
year or less event be released within 72 hours of the storm event, and 99% of
all of the stormwater runoff from greater than a 5-year event be released
within 120 hours of the storm event.
2. A porous landscape detention (PLD) holding cell/forebay is proposed as the
primary LID treatment method for the current development proposed within
Basins site. The PLD will provide standard 12-hour porous landscape
detention (PLD) treatment.
Salud Family Health Center
Preliminary Drainage Report 9
3. Final design details, and construction documentation shall be provided to the
City of Fort Collins for review prior to Final Development Plan approval.
4. Stormwater facility Standard Operating Procedures (SOP) will be provided by
the City of Fort Collins in the Development Agreement.
V. CONCLUSIONS
A. Compliance with Standards
1. The drainage design proposed with the proposed project complies with the City of Fort
Collins’ Stormwater Criteria Manual.
2. The drainage design proposed with this project complies with requirements for the
West Vine Basin.
3. The drainage plan and stormwater management measures proposed with the
proposed development are compliant with all applicable State and Federal regulations
governing stormwater discharge.
B. Drainage Concept
1. The drainage design proposed with this project will effectively limit any potential
damage associated with its stormwater runoff by providing detention and water
quality mitigation features.
2. The drainage concept for the proposed development is consistent with requirements
for the West Vine Basin.
Salud Family Health Center
Preliminary Drainage Report 10
References
1. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance No.
174, 2011, and referenced in Section 26-500 (c) of the City of Fort Collins Municipal Code.
2. Larimer County Urban Area Street Standards, Adopted January 2, 2001, Repealed and
Reenacted, Effective October 1, 2002, Repealed and Reenacted, Effective April 1, 2007.
3. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation
Service, United States Department of Agriculture.
4. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control
District, Wright-McLaughlin Engineers, Denver, Colorado, Revised April 2008.
APPENDIX A
HYDROLOGIC COMPUTATIONS
CHARACTER OF SURFACE:
Runoff
Coefficient
Percentage
Impervious Project: 1067-001
Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: ATC
Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date:
Concrete …….......……………….….……….………………..….…………………………………0.95 90%
Gravel ……….…………………….….…………………………..……………………………….. 0.50 40%
Roofs …….…….………………..……………….…………………………………………….. 0.95 90%
Pavers…………………………...………………..…………………………………………….. 0.40 22%
Lawns and Landscaping
Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0%
Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf
= 1.00 100-year Cf = 1.25
Basin ID
Basin Area
(s.f.)
Basin Area
(ac)
Area of
Asphalt
(ac)
Area of
Concrete
(ac)
Area of
Roofs
(ac)
Area of
Gravel
(ac)
Area of
Lawn, Rain
Garden, or
Landscaping
(ac)
2-year
Composite
Runoff
Coefficient
10-year
Composite
Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
Composite
% Imperv.
1 167402 3.71 0.00 0.00 0.00 0.00 3.71 0.25 0.25 0.31 0.0%
2 233621 5.21 1.64 0.25 1.04 0.00 2.28 0.64 0.64 0.80 53.8%
3 128166 2.94 0.00 0.00 0.00 0.00 2.94 0.25 0.25 0.31 0.0%
4 102827 2.36 0.00 1.18 1.18 0.00 0.00 0.95 0.95 1.19 90.0%
5 53579 1.23 0.00 0.62 0.62 0.00 0.00 0.95 0.95 1.19 90.0%
6 61174 1.47 0.00 0.74 0.74 0.00 0.00 0.95 0.95 1.19 90.0%
7 116348 2.67 0.00 1.34 1.34 0.00 0.00 0.95 0.95 1.19 90.0%
8 78531 1.80 1.44 0.09 0.00 0.00 0.27 0.85 0.85 1.06 84.5%
9 30867 0.71 0.00 0.35 0.35 0.00 0.00 0.95 0.95 1.19 90.0%
Overland Flow, Time of Concentration:
Project: 1067-001
Calculations By:
Date:
Gutter/Swale Flow, Time of Concentration:
Tt = L / 60V
Tc = Ti + Tt (Equation RO-2)
Velocity (Gutter Flow), V = 20·S½
Velocity (Swale Flow), V = 15·S½
NOTE: C-value for overland flows over grassy surfaces; C = 0.25
Is Length
>500' ?
C*Cf
(2-yr
Cf=1.00)
C*Cf
(10-yr
Cf=1.00)
C*Cf
(100-yr
Cf=1.25)
Length,
L
(ft)
Slope,
S
(%)
Ti
2-yr
(min)
Ti
10-yr
(min)
Ti
100-yr
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
2-yr
Tc
Rational Method Equation: Project: 1067-001
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
1 1 3.71 30 30 27 0.25 0.25 0.31 1.31 2.23 4.78 1.22 2.07 5.54
2 2 5.21 19 19 17 0.64 0.64 0.80 1.68 2.86 6.10 5.62 9.59 25.57
3 3 2.94 34 34 31 0.25 0.25 0.31 1.21 2.06 4.42 0.89 1.52 4.06
4 4 2.36 17 17 16 0.95 0.95 1.19 1.78 3.04 6.41 3.99 6.81 17.97
5 5 1.23 13 13 12 0.95 0.95 1.19 2.02 3.45 7.29 2.35 4.03 10.65
6 6 1.80 16 16 15 0.85 0.85 1.06 1.84 3.14 6.62 2.80 4.78 12.60
7 7 2.67 17 17 16 0.95 0.95 1.19 1.78 3.04 6.41 4.52 7.70 20.33
8 8 1.47 8 8 8 0.95 0.95 1.19 2.40 4.10 8.59 3.35 5.73 14.99
9 9 0.71 12 12 12 0.95 0.95 1.19 2.05 3.50 7.29 1.38 2.36 6.13
10 10 0.44 6 6 6 0.95 0.95 1.19 2.67 4.56 9.63 1.12 1.91 5.03
11 11 0.22 6 6 5 0.79 0.79 0.99 2.76 4.72 9.95 0.48 0.82 2.16
OS1 OS1 1.08 19 19 18 0.47 0.47 0.59 1.65 2.82 6.01 0.84 1.44 3.83
Area, A
(acres)
Intensity,
i2
(in/hr)
100-yr
Tc
(min)
DEVELOPED RUNOFF COMPUTATIONS
C100
Design
Point
Flow,
Q100
(cfs)
Flow,
Q2
(cfs)
10-yr
Tc
(min)
2-yr
Tc
(min)
C2
Flow,
Q10
(cfs)
Intensity,
i100
(in/hr)
Basin(s)
ATC
10/1/16
Intensity,
i10
(in/hr)
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
C10
Q C f C i A
CHARACTER OF SURFACE:
Runoff
Coefficient
Percentage
Impervious Project: 1067-001
Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: ATC
Asphalt ……....……………...……….....…...……………….…………………………………. 0.95 100% Date:
Concrete …….......……………….….……….………………..….……………………………… 0.95 90%
Gravel ……….…………………….….…………………………..………………………………. 0.50 40%
Roofs …….…….………………..……………….…………………………………………….. 0.95 90%
Pavers…………………………...………………..…………………………………………….. 0.40 22%
Lawns and Landscaping
Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0%
Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf
= 1.00 100-year Cf = 1.25
Basin ID
Basin Area
(s.f.)
Basin Area
(ac)
Area of
Asphalt
(ac)
Area of
Concrete
(ac)
Area of
Roofs
(ac)
Area of
Gravel
(ac)
Area of
Lawn, Rain
Garden, or
Landscaping
(ac)
2-year
Composite
Runoff
Coefficient
10-year
Composite
Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
Composite
% Imperv.
H1 719114 16.51 0.02 0.08 1.06 0.74 14.61 0.29 0.29 0.36 6.3%
HISTORIC COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I.
10-year Cf = 1.00
May 1, 2016
Overland Flow, Time of Concentration:
Project: 1067-001
Calculations By:
Date:
Gutter/Swale Flow, Time of Concentration:
Tt = L / 60V
Tc = Ti + Tt (Equation RO-2)
Velocity (Gutter Flow), V = 20·S½
Velocity (Swale Flow), V = 15·S½
NOTE: C-value for overland flows over grassy surfaces; C = 0.25
Is Length
>500' ?
C*Cf
(2-yr
Cf=1.00)
C*Cf
(10-yr
Cf=1.00)
C*Cf
(100-yr
Cf=1.25)
Length,
L
(ft)
Slope,
S
(%)
Ti
2-yr
(min)
Ti
10-yr
(min)
Ti
100-yr
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
2-yr
Tc
Rational Method Equation: Project: 1067-001
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
H1 H1 16.51 40 40 38 0.29 0.29 0.36 1.07 1.83 3.90 5.09 8.70 23.18
Historic 2-year cfs per acre= 0.31
(Q2/Area)
Area, A
(acres)
Intensity,
i2
(in/hr)
100-yr
Tc
(min)
HISTORIC RUNOFF COMPUTATIONS
C100
Design
Point
Flow,
Q100
(cfs)
Flow,
Q2
(cfs)
10-yr
Tc
(min)
2-yr
Tc
(min)
C2
Flow,
Q10
(cfs)
Intensity,
i100
(in/hr)
Basin(s)
ATC
May 1, 2016
Intensity,
i10
(in/hr)
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
C10
Q C f C i A
DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF
Figure RO-1—Estimate of Average Overland Flow Velocity for Use With the Rational Formula
2007-01 RO-13
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF
Table RO-3—Recommended Percentage Imperviousness Values
Land Use or
Surface Characteristics
Percentage
Imperviousness
Business:
Commercial areas 95
Neighborhood areas 85
Residential:
Single-family *
Multi-unit (detached) 60
Multi-unit (attached) 75
Half-acre lot or larger *
Apartments 80
Industrial:
Light areas 80
Heavy areas 90
Parks, cemeteries 5
Playgrounds 10
Schools 50
Railroad yard areas 15
Undeveloped Areas:
Historic flow analysis 2
Greenbelts, agricultural 2
Off-site flow analysis
(when land use not defined)
45
Streets:
Paved 100
Gravel (packed) 40
Drive and walks 90
Roofs 90
Lawns, sandy soil 0
Lawns, clayey soil 0
* See Figures RO-3 through RO-5 for percentage imperviousness.
C A = K A + ( 1 . 31 i 3 − 1 . 44 i 2 + 1 . 135 i − 0 . 12 ) for CA ≥ 0, otherwise CA = 0 (RO-6)
C CD = K CD + ( 0 . 858 i 3 − 0 . 786 i 2 + 0 . 774 i + 0 . 04 ) (RO-7)
C B = (CA + C CD ) 2
2007-01 RO-9
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF
Table RO-5— Runoff Coefficients, C
Percentage
Imperviousness Type C and D NRCS Hydrologic Soil Groups
2-yr 5-yr 10-yr 25-yr 50-yr 100-yr
0% 0.04 0.15 0.25 0.37 0.44 0.50
5% 0.08 0.18 0.28 0.39 0.46 0.52
10% 0.11 0.21 0.30 0.41 0.47 0.53
15% 0.14 0.24 0.32 0.43 0.49 0.54
20% 0.17 0.26 0.34 0.44 0.50 0.55
25% 0.20 0.28 0.36 0.46 0.51 0.56
30% 0.22 0.30 0.38 0.47 0.52 0.57
35% 0.25 0.33 0.40 0.48 0.53 0.57
40% 0.28 0.35 0.42 0.50 0.54 0.58
45% 0.31 0.37 0.44 0.51 0.55 0.59
50% 0.34 0.40 0.46 0.53 0.57 0.60
55% 0.37 0.43 0.48 0.55 0.58 0.62
60% 0.41 0.46 0.51 0.57 0.60 0.63
65% 0.45 0.49 0.54 0.59 0.62 0.65
70% 0.49 0.53 0.57 0.62 0.65 0.68
75% 0.54 0.58 0.62 0.66 0.68 0.71
80% 0.60 0.63 0.66 0.70 0.72 0.74
85% 0.66 0.68 0.71 0.75 0.77 0.79
90% 0.73 0.75 0.77 0.80 0.82 0.83
95% 0.80 0.82 0.84 0.87 0.88 0.89
100% 0.89 0.90 0.92 0.94 0.95 0.96
TYPE B NRCS HYDROLOGIC SOILS GROUP
0% 0.02 0.08 0.15 0.25 0.30 0.35
5% 0.04 0.10 0.19 0.28 0.33 0.38
10% 0.06 0.14 0.22 0.31 0.36 0.40
15% 0.08 0.17 0.25 0.33 0.38 0.42
20% 0.12 0.20 0.27 0.35 0.40 0.44
25% 0.15 0.22 0.30 0.37 0.41 0.46
30% 0.18 0.25 0.32 0.39 0.43 0.47
35% 0.20 0.27 0.34 0.41 0.44 0.48
40% 0.23 0.30 0.36 0.42 0.46 0.50
45% 0.26 0.32 0.38 0.44 0.48 0.51
50% 0.29 0.35 0.40 0.46 0.49 0.52
55% 0.33 0.38 0.43 0.48 0.51 0.54
60% 0.37 0.41 0.46 0.51 0.54 0.56
65% 0.41 0.45 0.49 0.54 0.57 0.59
70% 0.45 0.49 0.53 0.58 0.60 0.62
75% 0.51 0.54 0.58 0.62 0.64 0.66
80% 0.57 0.59 0.63 0.66 0.68 0.70
85% 0.63 0.66 0.69 0.72 0.73 0.75
90% 0.71 0.73 0.75 0.78 0.80 0.81
95% 0.79 0.81 0.83 0.85 0.87 0.88
100% 0.89 0.90 0.92 0.94 0.95 0.96
2007-01 RO-11
Urban Drainage and Flood Control District
RUNOFF DRAINAGE CRITERIA MANUAL (V. 1)
TABLE RO-5 (Continued)—Runoff Coefficients, C
Percentage
Imperviousness
Type A NRCS Hydrologic Soils Group
2-yr 5-yr 10-yr 25-yr 50-yr 100-yr
0% 0.00 0.00 0.05 0.12 0.16 0.20
5% 0.00 0.02 0.10 0.16 0.20 0.24
10% 0.00 0.06 0.14 0.20 0.24 0.28
15% 0.02 0.10 0.17 0.23 0.27 0.30
20% 0.06 0.13 0.20 0.26 0.30 0.33
25% 0.09 0.16 0.23 0.29 0.32 0.35
30% 0.13 0.19 0.25 0.31 0.34 0.37
35% 0.16 0.22 0.28 0.33 0.36 0.39
40% 0.19 0.25 0.30 0.35 0.38 0.41
45% 0.22 0.27 0.33 0.37 0.40 0.43
50% 0.25 0.30 0.35 0.40 0.42 0.45
55% 0.29 0.33 0.38 0.42 0.45 0.47
60% 0.33 0.37 0.41 0.45 0.47 0.50
65% 0.37 0.41 0.45 0.49 0.51 0.53
70% 0.42 0.45 0.49 0.53 0.54 0.56
75% 0.47 0.50 0.54 0.57 0.59 0.61
80% 0.54 0.56 0.60 0.63 0.64 0.66
85% 0.61 0.63 0.66 0.69 0.70 0.72
90% 0.69 0.71 0.73 0.76 0.77 0.79
95% 0.78 0.80 0.82 0.84 0.85 0.86
100% 0.89 0.90 0.92 0.94 0.95 0.96
RO-12 2007-01
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF
Figure RO-3— Watershed Imperviousness, Single-Family Residential Ranch Style Houses
2007-01 RO-15
Urban Drainage and Flood Control District
RUNOFF DRAINAGE CRITERIA MANUAL (V. 1)
Figure RO-4—Watershed Imperviousness, Single-Family Residential Split-Level Houses
RO-16 2007-01
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF
Figure RO-5—Watershed Imperviousness, Single-Family Residential Two-Story Houses
Figure RO-6—Runoff Coefficient, C, vs. Watershed Percentage Imperviousness NRCS Hydrologic
Soil Group A
2007-01 RO-17
Urban Drainage and Flood Control District
RUNOFF DRAINAGE CRITERIA MANUAL (V. 1)
Figure RO-7—Runoff Coefficient, C, vs. Watershed Percentage Imperviousness NRCS Hydrologic
Soil Group B
Figure RO-8—Runoff Coefficient, C, vs. Watershed Percentage Imperviousness NRCS Hydrologic
Soil Groups C and D
RO-18 2007-01
Urban Drainage and Flood Control District
APPENDIX B
WATER USUUSDA SOILS INFORMATION
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
Natural Area, Colorado
Resources
Conservation
Service
May 17, 2016
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 (http://
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 alternative means
2
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..................................................................................................................7
Soil Map................................................................................................................8
Legend..................................................................................................................9
Map Unit Legend................................................................................................10
Map Unit Descriptions........................................................................................10
Larimer County Area, Colorado......................................................................12
35—Fort Collins loam, 0 to 3 percent slopes..............................................12
36—Fort Collins loam, 3 to 5 percent slopes..............................................13
74—Nunn clay loam, 1 to 3 percent slopes.................................................14
References............................................................................................................16
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
scientists classified and named the soils in the survey area, they compared the
5
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
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
6
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.
7
8
Custom Soil Resource Report
Soil Map
4493150 4493210 4493270 4493330 4493390 4493450 4493510
4493150 4493210 4493270 4493330 4493390 4493450 4493510
490470 490530 490590 490650 490710 490770 490830 490890 490950 491010 491070
490470 490530 490590 490650 490710 490770 490830 490890 490950 491010 491070
40° 35' 33'' N
105° 6' 45'' W
40° 35' 33'' N
105° 6' 19'' W
40° 35' 19'' N
105° 6' 45'' W
40° 35' 19'' N
105° 6' 19'' W
N
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: 1:2,850 if printed on A landscape (11" x 8.5") sheet.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
Map Unit Legend
Larimer County Area, Colorado (CO644)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
35 Fort Collins loam, 0 to 3 percent
slopes
10.8 30.4%
36 Fort Collins loam, 3 to 5 percent
slopes
9.5 26.5%
74 Nunn clay loam, 1 to 3 percent
slopes
15.3 43.1%
Totals for Area of Interest 35.6 100.0%
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.
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
Custom Soil Resource Report
10
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
11
Larimer County Area, Colorado
35—Fort Collins loam, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: 2tlnc
Elevation: 4,020 to 6,730 feet
Mean annual precipitation: 14 to 16 inches
Mean annual air temperature: 46 to 48 degrees F
Frost-free period: 143 to 154 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Fort collins and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Fort Collins
Setting
Landform: Interfluves
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Pleistocene or older alluvium derived from igneous, metamorphic
and sedimentary rock and/or eolian deposits
Typical profile
Ap - 0 to 4 inches: loam
Bt1 - 4 to 9 inches: clay loam
Bt2 - 9 to 16 inches: clay loam
Bk1 - 16 to 29 inches: loam
Bk2 - 29 to 80 inches: loam
Properties and qualities
Slope: 0 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.20 to 2.00 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 12 percent
Salinity, maximum in profile: Nonsaline (0.1 to 1.0 mmhos/cm)
Sodium adsorption ratio, maximum in profile: 0.5
Available water storage in profile: High (about 9.1 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability classification (nonirrigated): 4c
Hydrologic Soil Group: C
Ecological site: Loamy Plains (R067BY002CO)
Custom Soil Resource Report
12
Minor Components
Nunn
Percent of map unit: 10 percent
Landform: Terraces
Landform position (three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Loamy Plains (R067BY002CO)
Vona
Percent of map unit: 5 percent
Landform: Interfluves
Landform position (two-dimensional): Backslope, footslope
Landform position (three-dimensional): Side slope, base slope
Down-slope shape: Linear
Across-slope shape: Linear
Ecological site: Sandy Plains (R067BY024CO)
36—Fort Collins loam, 3 to 5 percent slopes
Map Unit Setting
National map unit symbol: jpw9
Elevation: 4,800 to 5,500 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Fort collins and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Fort Collins
Setting
Landform: Terraces, fans
Landform position (three-dimensional): Base slope, riser
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium
Typical profile
H1 - 0 to 9 inches: loam
H2 - 9 to 20 inches: loam, clay loam
H2 - 9 to 20 inches: loam, silt loam, fine sandy loam
H3 - 20 to 60 inches:
H3 - 20 to 60 inches:
H3 - 20 to 60 inches:
Custom Soil Resource Report
13
Properties and qualities
Slope: 3 to 5 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 15 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water storage in profile: Very high (about 25.5 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Ecological site: Loamy Plains (R067XY002CO)
Minor Components
Ascalon
Percent of map unit: 5 percent
Kim
Percent of map unit: 3 percent
Stoneham
Percent of map unit: 2 percent
74—Nunn clay loam, 1 to 3 percent slopes
Map Unit Setting
National map unit symbol: jpxn
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 and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Nunn
Setting
Landform: Terraces, fans
Landform position (three-dimensional): Base slope, tread
Custom Soil Resource Report
14
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Alluvium
Typical profile
H1 - 0 to 10 inches: clay loam
H2 - 10 to 60 inches: clay loam, clay
H2 - 10 to 60 inches:
Properties and qualities
Slope: 1 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 15 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water storage in profile: Very high (about 18.9 inches)
Interpretive groups
Land capability classification (irrigated): 2e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Minor Components
Ulm
Percent of map unit: 10 percent
Satanta
Percent of map unit: 5 percent
Custom Soil Resource Report
15
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
16
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
17
APPENDIX C
SWMM Modeling; Detention Computations
^tDDϱ 3DJH
^tDD^, Dd/
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build 5.0.015)
--------------------------------------------------------------
*********************************************************
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
Snowmelt ............... NO
Groundwater ............ NO
Flow Routing ........... YES
Water Quality .......... NO
Infiltration Method ...... HORTON
Flow Routing Method ...... KINWAVE
Starting Date ............ JAN-01-2020 00:00:00
Ending Date .............. JAN-05-2020 00:00:00
Antecedent Dry Days ...... 0.0
Report Time Step ......... 00:15:00
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 ...... 4.816 3.669
Evaporation Loss ......... 0.000 0.000
Infiltration Loss ........ 0.924 0.704
Surface Runoff ........... 3.844 2.929
Final Surface Storage .... 0.074 0.056
Continuity Error (%) ..... -0.541
************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 0.000 0.000
Wet Weather Inflow ....... 3.846 1.253
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.000 0.000
External Inflow .......... 0.000 0.000
External Outflow ......... 3.846 1.253
Internal Outflow ......... 0.000 0.000
Evaporation Loss ......... 0.000 0.000
Initial Stored Volume .... 0.000 0.000
Final Stored Volume ...... 0.000 0.000
Continuity Error (%) ..... 0.000
********************************
Highest Flow Instability Indexes
********************************
All links are stable.
*************************
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 : 1.00
***************************
Subcatchment Runoff Summary
***************************
----------------------------------------------------------------------------------------------
Total Total Total Total Total Total Peak Runoff
Precip Runon Evap Infil Runoff Runoff Runoff Coeff
Subcatchment in in in in in 10^6 gal CFS
----------------------------------------------------------------------------------------------
Basin7 3.669 0.000 0.000 0.138 3.467 0.251 24.707 0.945
Basin1 3.669 0.000 0.000 1.708 1.971 0.199 8.835 0.537
Basin2 3.669 0.000 0.000 0.704 2.931 0.415 36.418 0.799
Basin8 3.669 0.000 0.000 0.217 3.393 0.166 16.312 0.925
Basin4 3.669 0.000 0.000 0.137 3.467 0.222 21.845 0.945
--------------------------------------------------------------------------------------------
System 3.669 0.000 0.000 0.704 2.929 1.253 106.903 0.798
******************
Node Depth Summary
******************
---------------------------------------------------------------------
Average Maximum Maximum Time of Max
Depth Depth HGL Occurrence
Node Type Feet Feet Feet days hr:min
---------------------------------------------------------------------
Outlet OUTFALL 0.00 0.00 96.00 0 00:00
Pond_2_Future STORAGE 0.26 3.24 100.24 0 02:08
Pond_1 STORAGE 2.57 4.38 101.38 0 08:18
*******************
Node InFlow Summary
*******************
-------------------------------------------------------------------------------------
Maximum Maximum Lateral Total
Lateral Total Time of Max Inflow Inflow
Inflow Inflow Occurrence Volume Volume
Node Type CFS CFS days hr:min 10^6 gal 10^6 gal
-------------------------------------------------------------------------------------
Outlet OUTFALL 0.00 0.61 0 01:42 0.000 1.253
Pond_2_Future STORAGE 24.71 24.71 0 00:40 0.251 0.251
Pond_1 STORAGE 82.20 82.98 0 00:40 1.002 1.253
**********************
Node Surcharge Summary
**********************
Surcharging occurs when water rises above the top of the highest conduit.
---------------------------------------------------------------------
Max. Height Min. Depth
Hours Above Crown Below Rim
Node Type Surcharged Feet Feet
---------------------------------------------------------------------
Pond_2_Future STORAGE 96.01 3.240 6.760
Pond_1 STORAGE 96.01 4.377 5.623
*********************
Node Flooding Summary
*********************
No nodes were flooded.
**********************
SWMM 5 Page 2
Storage Volume Summary
**********************
--------------------------------------------------------------------------------------
Average Avg Maximum Max Time of Max Maximum
Volume Pcnt Volume Pcnt Occurrence Outflow
Storage Unit 1000 ft3 Full 1000 ft3 Full days hr:min CFS
--------------------------------------------------------------------------------------
Pond_2_Future 1.510 1 26.245 10 0 02:08 1.22
Pond_1 65.079 9 143.714 19 0 08:18 0.61
***********************
Outfall Loading Summary
***********************
-----------------------------------------------------------
Flow Avg. Max. Total
Freq. Flow Flow Volume
Outfall Node Pcnt. CFS CFS 10^6 gal
-----------------------------------------------------------
Outlet 94.71 0.51 0.61 1.253
-----------------------------------------------------------
System 94.71 0.51 0.61 1.253
********************
Link Flow Summary
********************
-----------------------------------------------------------------------------
Maximum Time of Max Maximum Max/ Max/
|Flow| Occurrence Velocity Full Full
Link Type CFS days hr:min ft/sec Flow Depth
-----------------------------------------------------------------------------
Outlet_2 DUMMY 1.22 0 02:08
Outlet_1 DUMMY 0.61 0 01:42
*************************
Conduit Surcharge Summary
*************************
No conduits were surcharged.
Analysis begun on: Fri Oct 07 15:17:13 2016
Analysis ended on: Fri Oct 07 15:17:13 2016
Total elapsed time: < 1 sec
SWMM 5 Page 3
Link Outlet_1 Flow
Elapsed Time (hours)
0 10 20 30 40 50 60 70 80 90 100
Flow (CFS)
0.8
0.6
0.4
0.2
0.0
SWMM 5 Page 1
Node Pond_1 Volume
Elapsed Time (hours)
0 10 20 30 40 50 60 70 80 90 100
Volume (ft3)
160000.0
140000.0
120000.0
100000.0
80000.0
60000.0
40000.0
20000.0
0.0
SWMM 5 Page 1
APPENDIX D
LID/WATER QUALITY TREATMENT INFORMATION
Basin (s) Forebay ID Basin New
Impervious Area
(Ac.)
Req'd Min.
Area to be
Treated (Ac.)
LID Forebay Req'd
Min. Volume (Cu.-Ft.)
2, 8 1 3.42 2.57 3724
5,6 2 (Future) 2.43 1.82 2646
7 3 (Future) 2.40 1.80 2617
9 4 (Future) 0.64 0.48 696
4 5 (Future) 2.12 1.59 2309
10 6 (Future) 0.40 0.30 436
8.56 Ac.
75 %
75% On-Site Treatment by LID Summary Table
Total Site New Impervious Area Treated =
Percent of New Impervious Area Treated =
WATER QUALITY DESIGN CALCULATIONS
Forebay 1
Water Quality Capture Volume (12-Hr. PLD)
Project: 1067-001
By: ATC
Date: 9/15/16
REQUIRED STORAGE & OUTLET WORKS:
BASIN(S) : 2, 6
NEW IMPERVIOUS AREA (ac) = 3.42 <-- INPUT from impervious calcs
75% OF NEW IMPERVIOUS AREA (ac) = 2.565 <-- CALCULATED
PERCENT IMPERVIOUS = 100.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 1.0000 <-- CALCULATED
WQCV (watershed inches) = 0.400 <-- CALCULATED from Figure 3-2
WQCV (cu-ft) = 3724 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
WATER QUALITY DESIGN CALCULATIONS
Extended Detention-Pond 1
Water Quality Capture Volume - Extended Detention (40-Hr.)
Project: 1067-001
By: ATC
Date: 9/15/16
REQUIRED STORAGE & OUTLET WORKS:
BASIN(S) : 2, 6
BASIN AREA (ac) = 7.010 <-- INPUT from runoff calcs
BASIN IMPERVIOUSNESS PERCENT = 61.70 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 0.6170 <-- CALCULATED
WQCV (watershed inches) = 0.242 <-- CALCULATED from Figure 3-2
WQCV (ac-ft) = 0.141 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
REQ'D TREATMENT VOLUME (ac-ft) = 0.071 <-- CALCULATED
(50% OF BASIN RUNOFF)
WATER QUALITY DESIGN CALCULATIONS
Forebay 2 (Future)
Water Quality Capture Volume (12-Hr. PLD)
Project: 1067-001
By: ATC
Date: 9/15/16
REQUIRED STORAGE & OUTLET WORKS:
BASIN(S) : 5,6
NEW IMPERVIOUS AREA (ac) = 2.430 <-- INPUT from impervious calcs
75% OF NEW IMPERVIOUS AREA (ac) = 1.823 <-- CALCULATED
PERCENT IMPERVIOUS = 100.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 1.0000 <-- CALCULATED
WQCV (watershed inches) = 0.400 <-- CALCULATED from Figure 3-2
WQCV (cu-ft) = 2646 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
WATER QUALITY DESIGN CALCULATIONS
Extended Detention-Pond 2 (Future)
Water Quality Capture Volume - Extended Detention (40-Hr.)
Project: 1067-001
By: ATC
Date: 9/15/16
REQUIRED STORAGE & OUTLET WORKS:
BASIN(S) : 5,6
BASIN AREA (ac) = 2.700 <-- INPUT from runoff calcs
BASIN IMPERVIOUSNESS PERCENT = 90.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 0.9000 <-- CALCULATED
WQCV (watershed inches) = 0.401 <-- CALCULATED from Figure 3-2
WQCV (ac-ft) = 0.090 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
REQ'D TREATMENT VOLUME (ac-ft) = 0.045 <-- CALCULATED
(50% OF BASIN RUNOFF)
WATER QUALITY DESIGN CALCULATIONS
Forebay 3 (Future)
Water Quality Capture Volume (12-Hr. PLD)
Project: 1067-001
By: ATC
Date: 9/15/16
REQUIRED STORAGE & OUTLET WORKS:
BASIN(S) : 7
NEW IMPERVIOUS AREA (ac) = 2.403 <-- INPUT from impervious calcs
75% OF NEW IMPERVIOUS AREA (ac) = 1.802 <-- CALCULATED
PERCENT IMPERVIOUS = 100.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 1.0000 <-- CALCULATED
WQCV (watershed inches) = 0.400 <-- CALCULATED from Figure 3-2
WQCV (cu-ft) = 2617 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
WATER QUALITY DESIGN CALCULATIONS
Extended Detention-Pond 3 (Future)
Water Quality Capture Volume - Extended Detention (40-Hr.)
Project: 1067-001
By: ATC
Date: 9/15/16
REQUIRED STORAGE & OUTLET WORKS:
BASIN(S) : 7
BASIN AREA (ac) = 2.670 <-- INPUT from runoff calcs
BASIN IMPERVIOUSNESS PERCENT = 90.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 0.9000 <-- CALCULATED
WQCV (watershed inches) = 0.401 <-- CALCULATED from Figure 3-2
WQCV (ac-ft) = 0.089 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
REQ'D TREATMENT VOLUME (ac-ft) = 0.045 <-- CALCULATED
(50% OF BASIN RUNOFF)
WATER QUALITY DESIGN CALCULATIONS
Forebay 4 (Future)
Water Quality Capture Volume (12-Hr. PLD)
Project: 1067-001
By: ATC
Date: 9/15/16
REQUIRED STORAGE & OUTLET WORKS:
BASIN(S) : 9
NEW IMPERVIOUS AREA (ac) = 0.639 <-- INPUT from impervious calcs
75% OF NEW IMPERVIOUS AREA (ac) = 0.479 <-- CALCULATED
PERCENT IMPERVIOUS = 100.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 1.0000 <-- CALCULATED
WQCV (watershed inches) = 0.400 <-- CALCULATED from Figure 3-2
WQCV (cu-ft) = 696 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
WATER QUALITY DESIGN CALCULATIONS
Extended Detention-Pond 4 (Future)
Water Quality Capture Volume - Extended Detention (40-Hr.)
Project: 1067-001
By: ATC
Date: 9/15/16
REQUIRED STORAGE & OUTLET WORKS:
BASIN(S) : 9
BASIN AREA (ac) = 0.710 <-- INPUT from runoff calcs
BASIN IMPERVIOUSNESS PERCENT = 90.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 0.9000 <-- CALCULATED
WQCV (watershed inches) = 0.401 <-- CALCULATED from Figure 3-2
WQCV (ac-ft) = 0.024 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
REQ'D TREATMENT VOLUME (ac-ft) = 0.012 <-- CALCULATED
(50% OF BASIN RUNOFF)
WATER QUALITY DESIGN CALCULATIONS
Forebay 5 (Future)
Water Quality Capture Volume (12-Hr. PLD)
Project: 1067-001
By: ATC
Date: 9/15/16
REQUIRED STORAGE & OUTLET WORKS:
BASIN(S) : 4
NEW IMPERVIOUS AREA (ac) = 2.120 <-- INPUT from impervious calcs
75% OF NEW IMPERVIOUS AREA (ac) = 1.590 <-- CALCULATED
PERCENT IMPERVIOUS = 100.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 1.0000 <-- CALCULATED
WQCV (watershed inches) = 0.400 <-- CALCULATED from Figure 3-2
WQCV (cu-ft) = 2309 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
WATER QUALITY DESIGN CALCULATIONS
Forebay 6 (Future)
Water Quality Capture Volume (12-Hr. PLD)
Project: 1067-001
By: ATC
Date: 9/15/16
REQUIRED STORAGE & OUTLET WORKS:
BASIN(S) : 10
NEW IMPERVIOUS AREA (ac) = 0.400 <-- INPUT from impervious calcs
75% OF NEW IMPERVIOUS AREA (ac) = 0.300 <-- CALCULATED
PERCENT IMPERVIOUS = 100.00 <-- INPUT from impervious calcs
BASIN IMPERVIOUSNESS RATIO = 1.0000 <-- CALCULATED
WQCV (watershed inches) = 0.400 <-- CALCULATED from Figure 3-2
WQCV (cu-ft) = 436 <-- CALCULATED from UDFCD DCM V.3 Section 6.5
APPENDIX E
EROSION CONTROL REPORT
Salud Family Health Center
Preliminary Erosion Control Report
EROSION CONTROL REPORT
A comprehensive Erosion and Sediment Control Plan (along with associated details) will be included
with the final construction drawings. It should be noted, however, that 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 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 the Utility Plans. The Final Plans will contain a
full-size Erosion Control sheet 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 the Development Agreement for the development. Also,
the Site Contractor for this project will 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, prior to any earth disturbance activities. Prior to securing
said permit, the Site Contractor shall develop a comprehensive StormWater 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.
MAP POCKET
DRAINAGE EXHIBITS
X X
X
X
X
X
X
X X
X
X
GV
X X X X
X X X X X
X
X X
X X X X
X
X X X X X
S
S
X
X
X X X X
X X
X
X
X
X X X X
X
X
X X X X
X
X X X X
X X X
S
M M
M M
GAS
MH
M
GAS
MH
M
X X
1
4
10
2
4
5
7
GABRIEL PROPERTIES, LLC DAVID & GRETCHEN OSBORN 10 1760 W. LAPORTE AVE, LLC
WILLIAM S. ECKERT
ERNEST M. &
KRISTEN K.
SCHMIDTBERGER
ERNEST M. &
KRISTEN K.
SCHMIDTBERGER
CITY OF FORT COLLINS
LAPORTE AVENUE LLC
LAPORTE AVENUE LLC
JACOB BROADCASTING OF COLORADO
DAVID & GRETCHEN OSBORN
ONE-STORY
METAL BUILDING
DAVID & GRETCHEN OSBORN
GABRIEL PROPERTIES, LLC
9
6
11
8
11
2' CONCRETE PAN
PROPOSED INLET
PROPOSED INLET
PROPOSED INLET
PROPOSED INLET
PROPOSED INLET
PROPOSED INLET
PROPOSED POND OUTFALL
PROPOSED STORM MH
WITH PUMP
PROPOSED
WATER QUALITY WEIR
DETENTION / EXTENDED
DETENTION POND 1
IRRIGATION DITCH
EMERGENCY SPILLWAY
(CONCRETE WEIR)
BERM
FUTURE DETENTION/EXTENDED EXISTING BANK
DETENTION POND 2
LID FOREBAY 1
(12-HOUR PLD
DESIGN)
PROPOSED INLET
2' CONCRETE PAN
20' DRAINAGE EASEMENT
FUTURE
LID FEATURE 2
FUTURE
LID FEATURE 3
FUTURE LID FEATURE 5
TO TREAT BASIN 4 PRIOR
TO DISCHARGE INTO FUTURE
CONVEYANCE
LOT 1
LOT 2
LOT 6
LOT 4
LOT 3
LOT 5
LOT 7
PROPERTY LINE (TYP)
LOT LINE (TYP)
7
FUTURE CONVEYANCE (PIPE OR SWALE) TO
CONVEY FLOW FROM BASIN 4 INTO DETENTION
POND 1
FUTURE DETENTION/EXTENDED
DETENTION POND 3
5
1
3
2
3
POND EMERGENCY SPILL SECTION
TIES TO NATURAL GRADE TO MAINTAIN
FLOODPLAIN REQUIREMENTS
8
6
FUTURE
LID FEATURE 6
FUTURE
LID FEATURE 4
FUTURE DETENTION/EXTENDED
DETENTION POND 4
9
FUTURE DEVELOPMENT WITHIN
BASIN 10 ALLOWED TO MATCH
HISTORIC 100-YEAR RUNOFF
FROM EXISTING PARKING
LOT OF 4.3 CFS
OS1
OS1
CITY FLOODPLAIN BOUNDARY (TYP)
CITY FLOODWAY BOUNDARY (TYP)
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
LEGEND:
1. THE SIZE, TYPE AND LOCATION OF ALL KNOWN UNDERGROUND UTILITIES ARE
APPROXIMATE WHEN SHOWN ON THESE DRAWINGS. IT SHALL BE THE
RESPONSIBILITY OF THE CONTRACTOR TO VERIFY THE EXISTENCE OF ALL
UNDERGROUND UTILITIES IN THE AREA OF THE WORK. BEFORE COMMENCING
NEW CONSTRUCTION, THE CONTRACTOR SHALL BE RESPONSIBLE FOR LOCATING
ALL UNDERGROUND UTILITIES AND SHALL BE RESPONSIBLE FOR FOR ALL
UNKNOWN UNDERGROUND UTILITIES.
2. REFER TO THE PLAT FOR LOT AREAS, TRACT SIZES, EASEMENTS, LOT DIMENSIONS,
UTILITY EASEMENTS, OTHER EASEMENTS, AND OTHER SURVEY INFORMATION.
3. ALL PROJECT DATA IS ON THE CITY OF FORT COLLINS VERTICAL DATUM; NAVD 88.
SEE COVER SHEET FOR BENCHMARKS.
NOTES:
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.
Call before you dig.
R
City Engineer Date
Date
Date
Date
Date
Stormwater Utility
Parks & Recreation
Traffic Engineer
Date
Water & Wastewater Utility
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Environmental Planner
PROPOSED CONTOUR
PROPOSED SWALE
EXISTING CONTOUR
PROPOSED VERTICAL
PROPOSED OVERLAND FLOW DIRECTION
CURB & GUTTER
EXISTING STORM SEWER LINE
PROPERTY BOUNDARY
EXISTING INLET GRATE
PROPOSED UNDERDRAIN UD
PROPOSED STORM DRAIN
PROPOSED RIBBON CURB
PROPOSED PERMEABLE PAVERS
B
a
BASIN ACREAGE
DESIGN POINT
BASIN DELINEATION
MAJOR RUNOFF COEFFICIENT
PROPOSED BASIN LINES
Sheet
Of 15 Sheets
SALUD FAMILY HEALTH CENTER These drawings are
instruments of service
provided by Northern
Engineering Services, Inc.
and are not to be used for
any type of construction
unless signed and sealed by
a Professional Engineer in
the employ of Northern
Engineering Services, Inc.
NOT FOR CONSTRUCTION
REVIEW SET
ENGINEER ING
N O R T H E RN
10/05/16
301 North Howes Street, Suite 100
Fort Collins, Colorado 80521
www.northernengineering.com
Phone: 970.221.4158
C5.00
DRAINAGE EXHIBIT
( IN FEET )
0
1 INCH = 60 FEET
60 60 120 180
NORTH
KEYMAP
C5.00
75% On-Site Treatment by LID Summary Table
Basin (s) Forebay ID Basin New
Impervious Area
(Ac.)
Req'd Min. Area
to be Treated
(Ac.)
LID Forebay Req'd
Min. Volume (Cu.-Ft.)
2, 8 1 3.42 2.57 3724
5,6 2 (Future) 2.43 1.82 2646
7 3 (Future) 2.40 1.80 2617
9 4 (Future) 0.64 0.48 696
4 5 (Future) 2.12 1.59 2309
10 6 (Future) 0.40 0.30 436
Total Site New Impervious Area Treated = 8.56 Ac.
Percent of New Impervious Area Treated = 75 %
DRAINAGE SUMMARY TABLE
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C100 2-yr
Tc
(min)
100-yr
Tc
(min)
Q2
(cfs)
Q100
(cfs)
1 1 3.71 0.25 0.31 29.7 27.5 1.2 5.5
2 2 5.21 0.64 0.80 18.5 17.3 5.6 25.6
3 3 2.94 0.25 0.31 33.9 31.4 0.9 4.1
4 4 2.36 0.95 1.19 16.8 15.7 4.0 18.0
5 5 1.23 0.95 1.19 12.9 12.0 2.4 10.6
6 6 1.80 0.85 1.06 15.9 14.8 2.8 12.6
7 7 2.67 0.95 1.19 16.8 15.7 4.5 20.3
8 8 1.47 0.95 1.19 8.2 7.8 3.4 15.0
9 9 0.71 0.95 1.19 12.4 11.5 1.4 6.1
10 10 0.44 0.95 1.19 6.2 5.8 1.1 5.0
11 11 0.22 0.79 0.99 5.9 5.5 0.5 2.2
OS1 OS1 1.08 0.47 0.59 19.1 17.8 0.8 3.8
SWMM 5 Page 1
the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 10, Sep 22, 2015
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Apr 22, 2011—Apr 28,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
9
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
H1 H1 No 0.25 0.25 0.31 400 0.80% 34.2 34.2 31.7 0 0.00% N/A N/A 482 0.80% 1.34 6.0 40 40 38
HISTORIC TIME OF CONCENTRATION COMPUTATIONS
Gutter Flow Swale Flow
Design
Point
Basin
Overland Flow
ATC
May 1, 2016
Time of Concentration
(Equation RO-4)
3
1
1 . 87 1 . 1 *
S
Ti C Cf L
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
1 1 No 0.25 0.25 0.31 325 0.90% 29.7 29.7 27.5 0 0.00% 0.00 N/A 0 0.00% N/A N/A 30 30 27
2 2 No 0.25 0.25 0.31 110 1.00% 16.7 16.7 15.4 220 1.00% 2.00 1.8 0 0.00% N/A N/A 19 19 17
3 3 No 0.25 0.25 0.31 323 0.60% 33.9 33.9 31.4 0 0.00% N/A N/A 0 0.00% N/A N/A 34 34 31
4 4 No 0.25 0.25 0.31 90 1.00% 15.1 15.1 14.0 150 0.50% 1.41 1.8 0 0.00% N/A N/A 17 17 16
5 5 No 0.25 0.25 0.31 90 2.00% 12.0 12.0 11.1 75 0.50% 1.41 0.9 0 0.00% N/A N/A 13 13 12
6 6 No 0.25 0.25 0.31 90 1.00% 15.1 15.1 14.0 100 1.00% 2.00 0.8 0 0.00% N/A N/A 16 16 15
7 7 No 0.25 0.25 0.31 90 1.00% 15.1 15.1 14.0 150 0.50% 1.41 1.8 0 0.00% N/A N/A 17 17 16
8 8 No 0.25 0.25 0.31 20 2.00% 5.6 5.6 5.2 310 1.00% 2.00 2.6 0 0.00% N/A N/A 8 8 8
9 9 No 0.25 0.25 0.31 90 2.00% 12.0 12.0 11.1 50 1.00% 2.00 0.4 0 0.00% N/A N/A 12 12 12
10 10 No 0.25 0.25 0.31 20 2.00% 5.6 5.6 5.2 45 0.50% 1.41 0.5 0 0.00% N/A N/A 6 6 6
11 11 No 0.25 0.25 0.31 20 2.00% 5.6 5.6 5.2 30 1.00% 2.00 0.3 0 0.00% N/A N/A 6 6 5
OS1 OS1 No 0.25 0.25 0.31 120 1.00% 17.4 17.4 16.1 144 0.50% 1.41 1.7 0 0.00% N/A N/A 19 19 18
DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
Gutter Flow Swale Flow
Design
Point
Basin
Overland Flow
ATC
10/1/16
Time of Concentration
(Equation RO-4)
3
1
1 . 87 1 . 1 *
S
C Cf L
Ti
10 20213 0.44 0.00 0.22 0.22 0.00 0.00 0.95 0.95 1.19 90.0%
11 8566 0.22 0.16 0.01 0.00 0.00 0.05 0.79 0.79 0.99 76.7%
OS1 46907 1.08 0.00 0.10 0.25 0.00 0.73 0.47 0.47 0.59 28.8%
DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I.
10-year Cf = 1.00
10/1/16