HomeMy WebLinkAboutREDTAIL PONDS PERMANENT SUPPORTIVE HOUSING (AFFORDABLE HOUSING) - FDP - FDP130048 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFINAL DRAINAGE REPORT
FOR
FORT COLLINS HOUSING AUTHORITY
PERMANENT SUPPORTIVE HOUSING DEVELOPMENT
AT
FOSSIL BLVD/CONEJOS DRIVE
RED TAIL SUBDIVISION
FORT COLLINS, COLORADO
FOR
FORT COLLINS HOUSING AUTHORITY
1715 W. MOUNTAIN AVENUE
FORT COLLINS, COLORADO 80521
NOVEMBER 21, 2013
FCHA Permanent Supportive Housing Drainage Report Page 1 of 14
TABLE OF CONTENTS
SECTION 1 – ENGINEER’S CERTIFICATION BLOCK ........................................................................ 3
SECTION 2 – GENERAL LOCATION AND DESCRIPTION ................................................................. 4
SITE LOCATION .................................................................................................................... 4
DESCRIPTION OF PROPERTY .................................................................................................. 4
BENCHMARK INFORMATION .................................................................................................. 5
SECTION 3 – STORM DRAINAGE CRITERIA .................................................................................. 6
HYDROLOGIC CRITERIA ........................................................................................................ 6
HYDRAULIC CRITERIA ........................................................................................................... 6
SECTION 4 – DRAINAGE BASINS AND HISTORIC RUNOFF .............................................................. 7
HISTORIC BASINS ................................................................................................................. 7
PROPOSED DEVELOPED BASINS ............................................................................................ 7
PROPOSED DETENTION/WATER QUALITY POND ...................................................................... 9
REQUEST FOR VARIANCE TO REDUCE DETENTION REQUIREMENTS ............................................ 10
HISTORIC/DEVELOPED BASIN COMPARISON ........................................................................ 10
SECTION 5 – STORM WATER MODELING .................................................................................. 11
SECTION 6 – STORMWATER POLLUTION PREVENTION ................................................................. 12
TEMPORARY EROSION CONTROL ........................................................................................ 12
PERMANENT EROSION CONTROL......................................................................................... 12
SECTION 7 – CONCLUSIONS ................................................................................................... 13
SECTION 8 – REFERENCES ....................................................................................................... 14
LIST OF TABLES
TABLE 1. HISTORIC FLOWS- 2 AND 100 YEAR. (BASED ON RATIONAL METHOD) ............................. 7
TABLE 2. DEVELOPED FLOWS- 2 AND 100 YEAR. (BASED ON RATIONAL METHOD) ......................... 9
FCHA Permanent Supportive Housing Drainage Report Page 2 of 14
APPENDIX
Appendix A – Hydrologic Computations
1. Site Vicinity Map
2. Soil Map - Natural Resources Conservation Services (NRCS)
3. City of Fort Collins 100 year Flood Map
4. Figure 1- Existing Drainage Map
5. Rational Worksheets (Existing Flows)
6. Figure 2 - Developed Drainage Map
7. Rational Worksheets (Developed Flows)
8. Detention Volume Calculations
9. Orifice and Inlet Calculations
Appendix B – Hydraulic Computations
1. UD-SEWER Report
Appendix C – Referenced Information
1. Drainage and Erosion Control Report for Redtail
Appendix D – Utility Site Plans
1. Erosion Control Plan (CE1.0)
2. SWMP and Erosion Control Details (CE1.1)
3. Grading and Drainage Plan (C1.0 to C1.3)
4. Storm Drain Plan (C1.4)
5. Drainage Details (CD1.0, CD1.2)
FCHA Permanent Supportive Housing Drainage Report Page 3 of 14
SECTION 1 – ENGINEER’S CERTIFICATION BLOCK
I hereby certify that this Final Drainage Report for Fort Collins Housing Authority Permanent
Supportive Housing in Red Tail Subdivision was prepared by me (or under my direct
supervision) for the Owners thereof and meets or exceeds the criteria of the City of Fort Collins
Stormwater Design Standards.
Signature: ________________________________________________
Jason T. Claeys, PE
Registered Professional Engineer
State of Colorado No. 42122
FCHA Permanent Supportive Housing Drainage Report Page 4 of 14
SECTION 2 – GENERAL LOCATION AND
DESCRIPTION
SITE LOCATION
The Fort Collins Housing Authority Permanent Supportive Housing is located in the Red Tail
Subdivision at the intersection of Fossil Boulevard and Conejos Drive in the City of Fort Collins,
Colorado. Refer to Appendix A for the site vicinity map.
DESCRIPTION OF PROPERTY
The site is owned by Fort Collins Housing Authority, and is made up of three separate Tracts.
Tract AA open space with 0.120 acres, Lot 1 with 2.820 acres and Lot 2 with 0.145 acres, for a
combined total of 3.085 acres. For comparison purposes the drainage basins for the site used the
old lot lines prior to adjustment with a total area of 2.93 acres. The site is currently undeveloped
open land with approximately two-thirds of the site being used to stockpile earthwork and riprap
where it has been accessed from Conejos Road and Fossil Boulevard. The site generally slopes
from northwest to southeast with slopes from 2% to 25%. The soils within the site consist of
Kim loam and Nunn clay loam which have been classified based on the Natural Resources
Conservation Services (NRCS) and attached in Appendix A. Majority of the site is classified as
Kim loams having a Type B hydrologic soil group with a moderate inflation rate. The remaining
site is Tassel sandy loam with a Type D hydrologic soil group. For the purposes of this site
analysis the entire site was assumed to have a Type C hydrologic soil group.
There are no irrigation canals passing through the site.
A Geotechnical Engineering Study was performed for the site and measured ground water at
depths of 14' and 20.5' below existing grade.
The property is not located within the 100 year floodplain as shown on the City of Fort Collins
Flood Map attached in Appendix A. The Federal Emergency Management Agency (FEMA) had
no printed flood maps available since the site is not located within a mapped floodplain area.
(FEMA panel # 08069C100F)
The main purpose of this study it to analyze the existing and developed drainage patterns in order
to convey stormwater through the property to the historic drainage way southwest of the site. A
new parking lot to the west of the site and new building will be analyzed for stormwater
conveyance and water quality. The proposed scope of work will include new stormwater piping
and site grading to accommodate onsite stormwater detention, parking lot and roof drainage. A
new storm pipe for the pond outlet will be installed southwest to the historic Pond B that
eventually conveys stormwater to Fossil Creek to the south.
FCHA Permanent Supportive Housing Drainage Report Page 5 of 14
BENCHMARK INFORMATION
Topographic and survey information was provided by King Surveyors, Inc. Horizontal datum is
Colorado State Plate Coordinates NAD 83(2007) Datum and vertical datum is referenced from
Fort Collins Benchmark Y401, Record Elevation = 4,968.75, NGVD 1929 (unadjusted).
FCHA Permanent Supportive Housing Drainage Report Page 6 of 14
SECTION 3 – STORM DRAINAGE CRITERIA
This report was prepared to meet or exceed the City of Fort Collins stormwater criteria. The City
of Fort Collin’s Storm Drainage Design Criteria and Construction Manual (with all current 1997
Revisions and 2012 Amendments) (CoFC-SDDCCM) and the Urban Drainage Flood Control
District’s (UDFCD) Drainage Criteria Manual (USDCM) Volumes 1, 2 and 3 were referenced as
guidelines for this design.
HYDROLOGIC CRITERIA
The rational method was performed to calculate the peak historic runoff rates for each basin. The
City of Fort Collins runoff coefficients were used for the analysis. Weighted percent impervious
was calculated for each basin using Table RO-3 in the Urban Storm Drainage Criteria Manual.
The weighted runoff coefficients were calculated for each basin using Tables 3-2 and 3-3 in the
City of Fort Collins – Storm Drainage Design Criteria and Construction Standards (CoFC–
SDDCCS). The time of concentration was calculated using the equations given within section
2.4.1 of the USDCM equation RO-3. The intensity was calculated using the corresponding
storm rainfall depth and USDCM Equation RA-3. To account for the City of Fort Collins’ IDF
Curve, Coefficient 3 of the UDFCD’s intensity formula was adjusted to 0.7867. The City of Fort
Collins area has 2-yr 1-hr rainfall depth of 0.82 inches, a 10-yr 1 hr rainfall depth of 1.40 inches
and a 100-yr 1 hr rainfall depth of 2.86 inches. These depths do account for the 1997 adjusted
rainfall depths.
HYDRAULIC CRITERIA
The storm drainage system has been designed to convey the minor and major storm events
through the combination of inlets and storm sewer pipes.
UD SEWER model was used to analyze the pipe capacities and hydraulic grade line for the new
storm system. All supporting calculations and exhibits are located in the Appendix.
FCHA Permanent Supportive Housing Drainage Report Page 7 of 14
SECTION 4 – DRAINAGE BASINS AND HISTORIC
RUNOFF
HISTORIC BASINS
The site has been divided into four separate basins. Sub-Basins H1 and H2, shown on the
attached Drainage Figure 1 in Appendix A, sheet flow to the north and northwest. Basin H1
represents drainage that sheet flows to the existing Conejos Road that is conveyed to the existing
Pond B. Basin H2 sheet flows directly southwest off the site to the existing Pond B. Basin H3
sheet flow along steep slopes ( > 7%) to the east and towards South College Avenue. Basin H4
sheet flow along steep slopes ( > 7%) to the east and towards Frontage Road. All four basins
eventually convey stormwater to Fossil Creek south of the site. Rational method calculations
with peak flows for the individual sub-basins are attached in Appendix A and listed below in
Table 1.
Table 1. Historic Flows- 2 and 100 year. (Based on Rational Method)
Drainage
Basin
Design
Point
% Impervious Area (ac) Q-2 (cfs) Q-100 (cfs) 2-yr CFS/AC
H1 1 13.1% 0.19 0.16 0.65 0.84
H2 2 2.0% 0.19 0.12 0.52 0.63
H3 3 2.0% 0.91 0.59 2.56 0.64
H4 4 2.0% 1.65 0.88 3.84 0.54
TOTAL SITE 2.93 1.75 7.57 0.60
For each basin the total runoff in Cubic Feet per Second per Acre (CFS/AC) was calculated to
determine an equivalent runoff per acre for the entire site. It was determined that the site has an
average runoff per acres of 0.60CFS/AC. This value will be used to determine the allowed 2-yr
release rate for the onsite detention pond.
PROPOSED DEVELOPED BASINS
FCHA proposes to construct a building with associated parking, driveway and roadway
improvements, walks, retaining walls and other features throughout the site. The overall
imperviousness of the site will increase from 2.7% to 33.5%.
FCHA proposes to access the site from the same existing location in Conejos Road and Fossil
Boulevard. The majority of the site has been graded to drain towards the south to the propsoed
FCHA Permanent Supportive Housing Drainage Report Page 8 of 14
onside detention/water quality pond. The remaining to the east will continue to drain to South
College Avenue and Frontage Road. See Figure 2 in Appendix A for the proposed drainage Sub-
Basins and grading plan.
The site has been divided into six separate basins. Sub-Basin OS-1 to will continue to drain west
undetained to Conejos Road as historical, eventually being conveyed to the existing Pond B. This
basin consists of a paved drive entrance, sidewalks and lawn area. The overall runoff from this
basin will decrease by 0.34cfs in comparison to existing basin H-1
Sub-Basin OS-2 will continue to drain southwest as historical, eventually being conveyed offsite
undetained to the existing Pond B. This basin will remain mostly undisturbed and replanted with
lawn. The overall runoff from this basin will decrease by 0.24cfs in comparison to existing basin
H-2.
Sub-Basin A1 consists of the parking lot, sidewalks and lawn area where the majority of the
stromwater will sheet flow to three separate permeable paver systems and be conveyed through
the pavers, into the stone drainage base course and into an underdrain. The permeable pavers
will provided water quality and provide some detention volume required for the site. The
underdrain with in the permeable pavers will be piped to a central inlet within the middle of the
parking lot that conveys stormwater to the detention/water quality pond. Additionally, a small
section of roof area at the entrance will be piped to the underrain within the parking median. In
the event of the permeable paver systems becoming clogged, stormwater will be conveyed to a
curb cut that will drain to the center parking median with an underain and inlet. The inlet within
the media will be set slightly above the existing grade to promote infiltration into the
surrounding soil and underdrain system. If the inlet becomes clogged, stormwater will pond
within the parking area and eventually spill west to the proposed detention/water quality pond.
Sub-basin A2 consist of the building roof area, patio, lawn and the detention/water quality pond.
The stromwater from the roof will be piped and conveyed to a bio-swale along the south properly
line. The bio-swale will have a perforated underdrain pipe encased in washed stone to help
promote infiltration and to provide water quality. The patio and lawn area will sheet flow to an
inlet located near the bocce ball court that will also convey stormwater to the bio-swale. The bio-
swale will convey stormwater from basin A-2 to the detention/water quality pond.
Sub-basin A3 consist of sidewalks and steep lawn/landscaping with retaining walls. Stormwater
will sheet flow undetained to the southeast corner of the site as historically and eventually be
conveyed offsite to frontage road. The overall runoff from this basin will decrease by 3.08cfs in
comparison to existing basin H-4.
Sub-basin A4 consist of sidewalks and steep lawn/landscaping with retaining walls. Stormwater
will sheet flow undetained to the eastern properly line as historically and eventually be conveyed
offsite to South College Avenue. The overall runoff from this basin will decrease by 0.35cfs in
comparison to existing basin H-3. See Table 2 below for a summary of developed runoff flows.
FCHA Permanent Supportive Housing Drainage Report Page 9 of 14
Table 2. Developed Flows- 2, and 100 year. (Based on Rational Method)
Drainage Basin Design Point % Impervious Area (ac) Q-2 (cfs) Q-100 (cfs)
OS-1 OS-1 0.43 0.05 0.08 0.31
OS-2 OS-2 0.00 0.07 0.06 0.28
A1 1 0.63 0.73 1.40 5.30
A2 2 0.36 1.17 1.33 5.16
A3 3 0.05 0.22 0.18 0.76
A4 4 0.09 0.70 0.53 2.21
PROPOSED DETENTION/WATER QUALITY POND
Under the original Drainage and Erosion Control Report for Redtail Subdivision by North Star
Design, Inc. (dated November 29
th
, 2005), the proposed site falls within Sub-Basins 17, 18, 19,
20, 21, 22, 23 and 24 of the Redtail Drainage Plan, Sheet 15. Excerpts of the report and drainage
mapping are attached in appendix C for reference. Under this previously proposed design, Tract I
near the southwest corner of the site was designated for the area’s Water Quality Capture
Volume needs. No stormwater detention was proposed at that time.
Since the previous approval of the original 2005 Redtail drainage report, the City has observed
the need for stormwater detention from properties along the South College Avenue corridor in
the vicinity of the site. The City has therefore required FCHA provide detention for the
developed area of the site.
The previously approved design for the site consisted of single family residential development
with nearly 79% imperviousness over 2.86 acres, and a peak 100-year storm runoff rate of 28.5
CFS. The current proposed FCHA development has substantially lower imperviousness at 33.5%
and a peak undetained 100-year storm runoff rate of 12.37 CFS.
The proposed detention/water quality pond has been designed to capture stormwater runoff from
basins A1 and A2. The pond has been designed to detain for the 100yr storm rainfall event with
a controlled release of 1.13cfs to match the historic 2-yr release rate. The historic 2-yr release
rate has been determined based on a comparison of developed area draining to the
detention/water quality pond with the average historic 2-yr runoff per acre of 0.60CFS/AC. The
total area for developed base A2 and A2 is 1.90 Ac with a maximum historic releaser rate of
0.60CFS/Ac which is equal to 1.13cfs for basin A1 and A2. The controlled release will be
achieved by installing a steel plate over the outlet pipe with a 4-1/8" circular orifice cut out of the
steel plate. See attached orifice calculations in Appendix A.
Utilizing the detention volume calculation spreadsheet provided by UDFCD (version 2.33
Modified FAA Method) the total detention required for basin A1 and A2 is 0.223 AC-FT of
detention storage when released at the historic 2-year runoff rate of 1.13 CFS.
The proposed detention pond can accommodate approximately 0.218 AC-FT of storage by use of
vertical retaining walls. Additional detention storage, approximately 0.037 AC-FT, can be
provided in the median of the parking area and underneath the permeable pavers. The total
detention provided approximately 0.255 AC-FT.
FCHA Permanent Supportive Housing Drainage Report Page 10 of 14
Water Quality Capture Volume (WQCV) requirement for the developed basin A1 and A2 was
calculated to be 0.04 AC-FT based on UDFCD Best Management Practice calculation
spreadsheet. The permeable pavers are able to account for approximately 522 CF or 0.01 AC-FT
based on the UDFCD BMP permeable pavement system Spreadsheet. The detention/water
quality pond has been designed to treat for 0.03 AC-FT released over a 40-hr period.
REQUEST FOR VARIANCE TO REDUCE DETENTION REQUIREMENTS
As demonstrated in the previous section, it will be difficult to provide large storm event
detention storage in addition to the current site layout on a steeply sloped property. On behalf of
Fort Collins Housing Authority, JVA Inc. is requesting variance from the City of Fort Collins for
WQCV and stormwater detention requirements to allow the WQCV to be included within the
100-year storage volume rather than in addition to it. This represents a 1,633 cubic feet (0.04AC-
FT) reduction in required detention volume. In addition to the water quality outlet structure
within the pond, the site will have permeable pavers and bioswales to meet the City of Fort
Collins Low Impact Development (LID) and parking lot requirements.
HISTORIC/DEVELOPED BASIN COMPARISON
A majority of the site historically drains east to frontage road and South College Ave. The
developed drainage basins will alter the existing drainage patterns by providing onsite detention
and untimely reducing runoff to the east as stated above. The total developed flow to the west
from basin OS-1, OS-2, A1, and A2 is approximately 1.68 cfs for the 100 year storm event based
on the controlled release from the detention pond. The historic flow to the west is approximately
1.17 cfs for the 100 year storm event resulting in a net increase of 0.51 cfs which is considered
negligible. The small increase in runoff to the west to existing Pond B will have limited to no
significant impact to the downstream conveyance to Fossil Creek. Overall, the developed 100
year runoff that ultimately reaches Fossil Creek south of the site will be reduced from 7.57 cfs to
4.56 cfs, a net decrease of 3.01cfs. During the review of the original Redtail stormwater report it
was noted that the pond berm along the east edge of existing Pond C was not constructed per the
original design plans. It is recommended that the berm be completed by the Redtail owner per
the original design plans. Per the original design report for Redtail, the stormwater conveyance
system through pond B and C are capable of handing 250cfs from the west side of the tracts,
therefore the small increase in developed runoff from the site is considered negligible.
FCHA Permanent Supportive Housing Drainage Report Page 11 of 14
SECTION 5 – STORM WATER MODELING
The storm drain piping has been modeled using UD-SEWER to determine pipe size and
Hydraulic Grade Line profiles (HGL). The storm drain and underdrain located in the parking lot
has been modeled and the results have been attached in appendix B. The pipe has been designed
to handle the 100-yr flow. If this system becomes clogged stormwater will pond within the
median and parking areas and spill over the drive to the detention/water quality pond. The pond
outlet has been modeled to handle the 2-year historic release rate of 1.13cfs. If the pond outlet
becomes clogged an emergency spill way has been designed to handle the 100 year developed
runoff.
FCHA Permanent Supportive Housing Drainage Report Page 12 of 14
SECTION 6 – STORMWATER POLLUTION
PREVENTION
TEMPORARY EROSION CONTROL
A temporary erosion control plan is to be implemented for the site during construction.
Temporary erosion control measures include, but not limited to, slope and swale protection
provided by the use of erosion control wattles/sediment control logs, inlet protection, etc. All
temporary erosion control measures are to be removed after they are deemed unnecessary. Refer
to the Erosion Control Report for the FCHA Permanent Supportive Housing Dated November
21, 2013 for additional detail information.
PERMANENT EROSION CONTROL
Permanent erosion control measures include, but not limited to, the constructed detention pond,
riprap pads placed for culvert outlet protection, seeding and mulch placed to enable and
established vegetative growth, etc. Long-term maintenance of these erosion control measures
shall be the responsibility of the owner of the property. A general erosion control plan has been
provided in Appendix D
FCHA Permanent Supportive Housing Drainage Report Page 13 of 14
SECTION 7 – CONCLUSIONS
This Final Drainage Report for FCHA Permanent Supportive Housing has been prepared to
comply with the stormwater criteria set by the City of Fort Collins.
The proposed drainage systems presented in this report are designed to convey the proposed peak
stormwater runoff through the site to the proposed detention/water quality pond. Through
calculations and review of the proposed storm drain system, there appears to be adequate
capacity to convey the proposed flows. This report also proposes best management practices for
erosion control, permanent landscaping, riprap, and on-site construction facilities.
It can therefore be concluded that development of the detention pond complies with all of the
stormwater jurisdictional criteria and will not adversely affect the existing streets, storm drain
system and/or detention/water quality facilities.
FCHA Permanent Supportive Housing Drainage Report Page 14 of 14
SECTION 8 – REFERENCES
1. Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3), Urban Drainage and Flood
Control District, June 2001, Revised April 2008.
2. Storm Drainage Criteria Manual and Construction Standards, City of Fort Collins Storm
Water Utility, City of Fort Collins, Colorado, Updated January, 1997 with 2012
amendments.
3. “Hydrologic Group Rating for Larimer County Area, Colorado”, USDA-Natural
Resources Conservation Service, National Cooperative Soil Survey. Web Soil Survey
URL: http://websoilsurvey.nrcs.usda.gov. [12/6/2012]
4. Drainage and Erosion Control Report for Redtail, prepared by North Star Design, Inc.,
Dated November 29, 2005
5. Urban Drainage (UD-SEWER), Urban Drainage and Flood Control District, Version
1.4.0.20 dated 2009.
APPENDIX A – HYDROLOGIC COMPUTATIONS
1. Site Vicinity Map
2. Soil Map - Natural Resources Conservation Services (NRCS)
3. City of Fort Collins 100 year Flood Map
4. Figure 1- Existing Drainage Map
5. Rational Worksheets (Existing Flows)
6. Figure 2 - Developed Drainage Map
7. Rational Worksheets (Developed Flows)
8. Detention Volume Calculations
9. Orifice and Inlet Calculations
PERMANENT SUPPORTIVE HOUSING DEVELOPMENT
FORT COLLINS, COLORADO
VICINITY MAP
NOT TO SCALE
Hydrologic Soil Group—Larimer County Area, Colorado
(Fort Collins Housing Authority)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/18/2013
Page 1 of 4
4484980 4485000 4485020 4485040 4485060 4485080 4485100 4485120 4485140
4484980 4485000 4485020 4485040 4485060 4485080 4485100 4485120 4485140
493220 493240 493260 493280 493300 493320 493340 493360 493380 493400 493420 493440 493460 493480
493220 493240 493260 493280 493300 493320 493340 493360 493380 493400 493420 493440 493460 493480
40° 31' 1'' N
105° 4' 48'' W
40° 31' 1'' N
105° 4' 37'' W
40° 30' 55'' N
105° 4' 48'' W
40° 30' 55'' N
105° 4' 37'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 50 100 200 300
Feet
0 15 30 60 90
Meters
Map Scale: 1:1,200 if printed on A landscape (11" x 8.5") sheet.
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: 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
the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
53 Kim loam, 1 to 3 percent
slopes
B 0.0 0.1%
54 Kim loam, 3 to 5 percent
slopes
B 2.9 40.7%
63 Longmont clay, 0 to 3
percent slopes
C 0.2 3.3%
74 Nunn clay loam, 1 to 3
percent slopes
C 1.3 18.2%
90 Renohill clay loam, 3 to 9
percent slopes
C 0.3 3.8%
106 Tassel sandy loam, 3 to
25 percent slopes
D 2.5 33.8%
Totals for Area of Interest 7.2 100.0%
Hydrologic Soil Group—Larimer County Area, Colorado Fort Collins Housing Authority
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/18/2013
Page 3 of 4
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Larimer County Area, Colorado Fort Collins Housing Authority
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/18/2013
Page 4 of 4
Fort Collins Housing Authority
City of Fort Collins Flood Map
This map is a user generated static output from the City of Fort Collins FCMaps
Internet mapping site and is for reference only. Data layers that appear on this
map may or may not be accurate, current, or otherwise reliable.
6,281
City of Fort Collins - GIS
0.2
1:
WGS_1984_Web_Mercator_Auxiliary_Sphere
0 0.10 0.2 Miles
Notes
Legend
FEMA Floodplain
FEMA High Risk - Floodway
FEMA High Risk - 100 Year
FEMA Moderate Risk - 100 / 500 Year
City Floodplains
City High Risk - Floodway
City High Risk - 100 Year
City Moderate Risk - 100 Year
Natural Areas
City Limits
PROJECT LOCATION
JVA Incorporated Job Name: FCHA-PSH I% C2 C100
25 Old Town Square Job Number: 1980c Streets Paved 100% 0.95 1.00
Fort Collins, CO 80524 Date: 11/20/13 Concrete Drives/Walks 90% 0.95 1.00
Ph: 970.225.9099 By: DH Roof 90% 0.95 1.00
Fax: 970.225.6923 Gravel 40% 0.50 0.63
Playground 10% 0.20 0.25
FCHA-PSH Historic Lawn - Flat (<2%) 2% 0.20 0.25
Historic Runoff Coefficient & Time of Concentration Calculations Historic Lawn - Medium (2-7%) 2% 0.25 0.31
Location: Fort Collins Historic Lawn - Steep > 7% 2% 0.35 0.44
Minor Design Storm: 2
Major Design Storm: 100
Soil Type: C/D
Basin Design Data
I (%) = 100% 90% 90% 40% 10% 2% 2% 2% I (%) tc Comp
tc
Final
Basin
Name
Design
Point
Apaved
streets
(sf)
Adrives/co
nc (sf)
Aroof
(sf)
Agravel
(sf)
Aplygnd
(sf)
Alawn-
FLAT
(sf)
Alawn-
MED
(sf)
Alawn-
STEEP
(sf)
ATotal
(sf)
ATotal
(ac)
Imp
(%)
C2 C5 C10 C100
Upper
most
Length
(ft)
Slope
(%)
ti
(min)
Length
(ft)
Slope
(%)
Type of Land Surface Cv
JVA Incorporated Job Name: FCHA-PSH I% C2 C100
25 Old Town Square Job Number: 1980c Streets, Parking, Drives 100% 0.95 1.00
Fort Collins, CO 80524 Date: 11/20/13 Concrete/Asphalt Drives 90% 0.95 1.00
Ph: 970.225.9099 By: DH Roof 90% 0.95 1.00
Fax: 970.225.6923 Permeable Pavers 40% 0.50 0.63
FCHA-PSH Lawn - Flat (<2%) 0% 0.20 0.25
Composite Runoff Coefficient Calculations Lawn - Medium (2-7%) 0% 0.25 0.31
Location: Fort Collins Lawn - Steep > 7% 0% 0.35 0.44
Minor Design Storm: 2
Major Design Storm: 100
Soil Type: C/D
I (%) = 100% 90% 90% 40% 0% 0% 0% I (%)
Basin
Name
Design
Point
Apaved
streets
(sf)
Adrives/c
onc (sf)
Aroof
(sf)
Apavers
(sf)
Alawn-
FLAT
(sf)
Alawn-
MED
(sf)
Alawn-
STEEP
(sf)
ATotal
(sf)
ATotal
(ac)
Imp
(%)
C2 C100
OS-1 OS-1 885 1,165 2,050 0.05 43.2% 0.61 0.68
OS-2 OS-2 3,218 3,218 0.07 0.0% 0.35 0.44
A1 1 19,505 729 4,518 6,859 31,611 0.73 63.3% 0.72 0.78
A2 2 2,742 16,691 2,565 28,828 50,826 1.17 36.4% 0.53 0.59
A3 3 311 528 3,160 5,472 9,471 0.22 5.2% 0.34 0.42
A4 4 3,186 0 14,036 13,381 30,603 0.70 9.4% 0.37 0.44
A1+A2 5 22,247 17,420 7,083 6,859 28,828 0 82,437 1.89 46.7% 0.60 0.66
A3+A4 6 3,497 0 528 0 17,196 18,853 40,074 0.92 8.4% 0.36 0.44
Runoff Coeff's
Basin Design Data
A3+A4 6 3,497 0 528 0 17,196 18,853 40,074 0.92 8.4% 0.36 0.44
A1-A4 7 0 25,744 17,420 7,611 6,859 46,024 18,853 122,511 2.81 34.2% 0.52 0.59
OS1+OS2 8 885 0 0 0 0 0 4,383 5,268 0.12 16.8% 0.45 0.53
TOTAL SITE 885 25,744 17,420 7,611 6,859 46,024 23,236 127,779 2.93 33.5% 0.52 0.59
1980c - Rational Calculations.xlsx Developed C Page 2 of 5
JVA Incorporated Job Name: FCHA-PSH
25 Old Town Square Job Number: 1980c
Fort Collins, CO 80524 Date: 11/20/13
Ph: 970.225.9099 By: DH
Fax: 970.225.6923
FCHA-PSH
Time of Concentration Calculations
Location: Fort Collins
Minor Design Storm: 2
Major Design Storm: 100
Soil Type: C/D
Sub-Basin Data tc
Comp
tc
Final
Basin
Name
Design Point
ATotal
(ac)
C5
Upper
most
Length
(ft)
Slope
(%)
ti
(min)
Length
(ft)
Slope (%) Type of Land Surface Cv
Velocity
(fps)
tt
(min)
Time of
Conc
ti
+ tt
= tc
Total
Length
(ft)
tc
=(L/180)+
10 (min)
Min
tc
OS-1 OS-1 0.05 0.61 35 2.0% 4.2 5 2.0%
Paved areas & shallow
paved swales
20 2.8 0.0 4.3 40 10.2 5.0
OS-2 OS-2 0.07 0.35 65 3.0% 7.7 5 2.0%
Paved areas & shallow
paved swales
20 2.8 0.0 7.7 70 10.4 7.7
A1 1 0.73 0.72 54 2.0% 4.0 210 1.0%
Paved areas & shallow
paved swales
JVA Incorporated Job Name: FCHA-PSH
25 Old Town Square Job Number: 1980c
Fort Collins, CO 80524 Date: 11/20/13
Ph: 970.225.9099 By: DH
Fax: 970.225.6923
FCHA-PSH Developed Storm Runoff Calculations
Design Storm : 2 Year Point Hour Rainfall (P1) : 0.82 I = (28.5 P1) / ((10 + TC)^0.786651)
Basin Name
Design Point
Area (ac)
Runoff Coeff
tc (min)
C*A (ac)
I (in/hr)
Q (cfs)
Total tc (min)
ΣC*A (ac)
I (in/hr)
Q (cfs)
Inlet Type
Q intercepted
Q carryover
Pipe Size (in)
or equivalent
Pipe Material
Slope (%)
Pipe Flow
(cfs)
Max Pipe
Capacity (cfs)
Length (ft)
Velocity (fps)
tt (min)
Total Time
(min)
Notes
OS-1 OS-1 0.05 0.61 5.00 0.03 2.78 0.08
OS-2 OS-2 0.07 0.35 7.70 0.03 2.44 0.06
Basins OS-1 and OS-2 Routed 7.70 0.05 2.44 0.13
A1 1 0.73 0.72 5.80 0.52 2.67 1.40
A2 2 1.17 0.53 10.90 0.62 2.14 1.33
A3 3 0.22 0.34 8.60 0.07 2.35 0.18
A4 4 0.70 0.37 12.00 0.26 2.06 0.53
Basins A1 and A2 Routed 10.90 1.14 2.14 2.45
Basins A3 and A4 Routed 12.00 0.33 2.06 0.68
12.00 1.53 2.06 3.15 3.1
Pipe/Swale Travel Time
Entire Site
Direct Runoff Total Runoff Inlets Pipe
1980c - Rational Calculations.xlsx Q Minor Page 5 of 5
JVA Incorporated Job Name: FCHA-PSH
25 Old Town Square Job Number: 1980c
Fort Collins, CO 80524 Date: 11/20/13
Ph: 970.225.9099 By: DH
Fax: 970.225.6923
FCHA-PSH Developed Storm Runoff Calculations
Design Storm : 100 Year Point Hour Rainfall (P1) : 2.86 I = (28.5 P1) / ((10 + TC)^0.786651)
Basin Name
Design Point
Area (ac)
Runoff Coeff
tc (min)
C*A (ac)
I (in/hr)
Q (cfs)
Total tc (min)
ΣC*A (ac)
I (in/hr)
Q (cfs)
Inlet Type
Q intercepted
Q carryover
Pipe Size (in)
or equivalent
Pipe Material
Slope (%)
Pipe Flow
(cfs)
Max Pipe
Capacity (cfs)
Length (ft)
Velocity (fps)
tt (min)
Total Time
(min)
Notes
OS-1 OS-1 0.05 0.68 5.00 0.03 9.70 0.31
OS-2 OS-2 0.07 0.44 7.70 0.03 8.52 0.28 0.5
'Basins OS-1 and OS-2 Routed 7.70 0.06 8.52 0.55
A1 1 0.73 0.78 5.80 0.57 9.31 5.30 15 in PVC 0.5% 5.3 6.4 280 10.0 0.47 0.47
A2 2 1.17 0.59 10.90 0.69 7.47 5.16 15 in PVC 1.6% 0.0 11.4 160 10.0 0.27 0.27
A3 3 0.22 0.42 8.60 0.09 8.19 0.76 15 in PVC 2.0% 0.0 12.8 5 10.0 0.01 0.01
A4 4 0.70 0.44 12.00 0.31 7.18 2.21
'Basins A1 and A2 Routed 10.90 1.26 7.47 9.41
Basins A3 and A4 Routed 12.00 0.40 7.18 2.88
12.00 1.72 7.18 12.37 12.4
Pipe/Swale Travel Time
Entire Site
Direct Runoff Total Runoff Inlets Pipe
1980c - Rational Calculations.xlsx Q100 Page 4 of 5
Project:
Basin ID:
Design Information (Input): Design Information (Input):
Catchment Drainage Imperviousness Ia = 46.70 percent Catchment Drainage Imperviousness I
a = 46.70 percent
Catchment Drainage Area A = 1.900 acres Catchment Drainage Area A = 1.900 acres
Predevelopment NRCS Soil Group Type = C A, B, C, or D Predevelopment NRCS Soil Group Type = C A, B, C, or D
Return Period for Detention Control T = 2 years (2, 5, 10, 25, 50, or 100) Return Period for Detention Control T = 100 years (2, 5, 10, 25, 50, or 100)
Time of Concentration of Watershed Tc = 10 minutes Time of Concentration of Watershed Tc = 10 minutes
Allowable Unit Release Rate q = 0.60 cfs/acre Allowable Unit Release Rate q = 0.60 cfs/acre
One-hour Precipitation P1 = 0.82 inches One-hour Precipitation P
1 = 2.86 inches
Design Rainfall IDF Formula i = C1* P
1/(C2
+Tc)^C
3 Design Rainfall IDF Formula i = C1
* P1/(C
2+Tc
)^C3
Coefficient One C1 = 28.50 Coefficient One C
1 = 28.50
Coefficient Two C2 = 10 Coefficient Two C
2 = 10
Coefficient Three C3 = 0.78665 Coefficient Three C
3 = 0.78665
Determination of Average Outflow from the Basin (Calculated): Determination of Average Outflow from the Basin (Calculated):
Runoff Coefficient C = 0.32 Runoff Coefficient C = 0.60
Inflow Peak Runoff Qp-in = 1.36 cfs Inflow Peak Runoff Qp-in = 8.87 cfs
Allowable Peak Outflow Rate Qp-out = 1.13 cfs Allowable Peak Outflow Rate Qp-out = 1.13 cfs
Mod. FAA Minor Storage Volume = 175 cubic feet Mod. FAA Major Storage Volume = 10,136 cubic feet
Mod. FAA Minor Storage Volume = 0.004 acre-ft Mod. FAA Major Storage Volume = 0.233 acre-ft
5 <- Enter Rainfall Duration Incremental Increase Value Here (e.g. 5 for 5-Minutes)
Rainfall Rainfall Inflow Adjustment Average Outflow Storage Rainfall Rainfall Inflow Adjustment Average Outflow Storage
Duration Intensity Volume Factor Outflow Volume Volume Duration Intensity Volume Factor Outflow Volume Volume
minutes inches / hr acre-feet "m" cfs acre-feet acre-feet minutes inches / hr acre-feet "m" cfs acre-feet acre-feet
(input) (output) (output) (output) (output) (output) (output) (input) (output) (output) (output) (output) (output) (output)
0 0.00 0.000 0.00 0.00 0.000 0.000 0 0.00 0.000 0.00 0.00 0.000 0.000
5 2.78 0.012 1.00 1.13 0.008 0.004 5 9.68 0.076 1.00 1.13 0.008 0.068
10 2.21 0.019 0.99 1.12 0.015 0.003 10 7.72 0.121 0.99 1.12 0.015 0.106
15 1.86 0.023 0.83 0.93 0.019 0.004 15 6.48 0.153 0.83 0.93 0.019 0.133
20 1.61 0.027 0.75 0.84 0.023 0.004 20 5.61 0.176 0.75 0.84 0.023 0.153
25 1.43 0.030 0.70 0.79 0.027 0.003 25 4.97 0.195 0.70 0.79 0.027 0.168
30 1.28 0.032 0.66 0.75 0.031 0.001 30 4.48 0.211 0.66 0.75 0.031 0.180
35 1.17 0.034 0.64 0.72 0.035 -0.001 35 4.08 0.224 0.64 0.72 0.035 0.189
40 1.08 0.036 0.62 0.70 0.039 -0.003 40 3.76 0.236 0.62 0.70 0.039 0.197
45 1.00 0.038 0.61 0.69 0.043 -0.005 45 3.48 0.246 0.61 0.69 0.043 0.204
50 0.93 0.039 0.60 0.68 0.047 -0.007 50 3.25 0.255 0.60 0.68 0.047 0.209
55 0.88 0.040 0.59 0.67 0.050 -0.010 55 3.06 0.264 0.59 0.67 0.050 0.213
60 0.83 0.042 0.58 0.66 0.054 -0.013 60 2.88 0.272 0.58 0.66 0.054 0.217
65 0.78 0.043 0.58 0.65 0.058 -0.016 65 2.73 0.279 0.58 0.65 0.058 0.220
70 0.74 0.044 0.57 0.64 0.062 -0.019 70 2.60 0.285 0.57 0.64 0.062 0.223
75 0.71 0.045 0.57 0.64 0.066 -0.021 75 2.47 0.291 0.57 0.64 0.066 0.225
80 0.68 0.045 0.56 0.63 0.070 -0.024 80 2.37 0.297 0.56 0.63 0.070 0.227
85 0.65 0.046 0.56 0.63 0.074 -0.028 85 2.27 0.303 0.56 0.63 0.074 0.229
90 0.62 0.047 0.55 0.63 0.078 -0.031 90 2.18 0.308 0.55 0.63 0.078 0.230
95 0.60 0.048 0.55 0.62 0.082 -0.034 95 2.10 0.313 0.55 0.62 0.082 0.231
100 0.58 0.049 0.55 0.62 0.085 -0.037 100 2.02 0.317 0.55 0.62 0.085 0.232
105 0.56 0.049 0.55 0.62 0.089 -0.040 105 1.95 0.322 0.55 0.62 0.089 0.232
110 0.54 0.050 0.54 0.62 0.093 -0.043 110 1.89 0.326 0.54 0.62 0.093 0.233
115 0.52 0.050 0.54 0.61 0.097 -0.047 115 1.83 0.330 0.54 0.61 0.097 0.233
Project:
Basin ID:
Design Information (Input): #1 Horiz. #2 Horiz. #1 Vert. #2 Vert.
Circular Opening: Diameter in Inches Dia. = 4.06 15.00 inches
OR
Rectangular Opening: Width in Feet W = 3.00 3.00 ft.
Length (Height for Vertical) L or H = 3.00 3.00 ft.
Percentage of Open Area After Trash Rack Reduction % open = 75 75 %
Orifice Coefficient Co = 0.65 0.65
Weir Coefficient Cw = 2.80 2.80
Orifice Elevation (Bottom for Vertical) Eo = 4985.56 4985.56 ft.
Calculation of Collection Capacity:
Net Opening Area (after Trash Rack Reduction) Ao = 6.75 6.75 0.00 0.00 sq. ft.
OPTIONAL: User-Overide Net Opening Area Ao = sq. ft.
Perimeter as Weir Length Lw = 10.50 10.50 ft.
OPTIONAL: User-Overide Weir Length Lw = ft.
Top Elevation of Vertical Orifice Opening, Top = 0.34 1.25 ft.
Center Elevation of Vertical Orifice Opening, Cen = 0.17 0.63 ft.
Horizontal Orifices Vertical Orifices
Labels Water WQCV #1 Horiz. #1 Horiz. #2 Horiz. #2 Horiz. #1 Vert. #2 Vert. Total Target Volumes
for WQCV, Minor, Surface Plate/Riser Weir Orifice Weir Orifice Collection Collection Collection for WQCV, Minor,
& Major Storage Elevation Flow Flow Flow Flow Flow Capacity Capacity Capacity & Major Storage
W.S. Elevations ft cfs cfs cfs cfs cfs cfs cfs cfs Volumes
(input) (linked) (User-linked) (output) (output) (output) (output) (output) (output) (output) (link for goal seek)
Bottom of pond 4987.76 0.00 95.94 52.22 95.94 52.22 0.00 0.00 104.45
4988.00 0.00 112.06 55.00 112.06 55.00 0.00 0.00 110.00
4989.00 0.00 187.58 65.30 187.58 65.30 0.00 0.00 130.61
4990.00 0.00 275.06 74.19 275.06 74.19 0.00 0.00 148.38
4991.00 0.00 373.03 82.12 373.03 82.12 0.00 0.00 164.25
Spillway 4991.50 0.00 425.62 85.81 425.62 85.81 0.00 0.00 171.63
4992.00 0.00 480.48 89.35 480.48 89.35 0.00 0.00 178.71
Top of Berm 4993.00 0.01 596.63 96.04 596.63 96.04 0.00 0.00 192.08
0.01 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.01 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.01 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.01 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.01 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.01 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.01 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.02 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
FCHA - Permanent Supportive Housing
Pond Summary
Design Engineer:
Design Firm:
Project Number:
Date:
Pond Summary Table
0.04
4989.58
9.41
4 2/16
1.13
0.037
0.218
0.255
0.233
0.022
4991.33
9.41
9.00
1.5
4991.50
4993.00
Excess 100-yr Detention Volume (acre-ft)
D. Harner
JVA, Inc
Proposal
November 20, 2013
100-yr Detention Volume pond (acre-ft)
100-yr Water Surface Elev. (ft)
Detention Pond Summary Table
Water Quality Capture Volume-Pond (acre-ft)
WQCV Water Surface Elev. Required (ft)
100-yr Pond Max Inflow (cfs) (routed)
100-yr Site Release Rate (cfs)
Outlet Orifice Size (in)
100-yr Detention Volume pavers (acre-ft)
Total 100-yr Detention Volume Provided (acre-ft)
Total 100-yr Detention Volume Required (acre-ft)
Spillway Summary Table
Top of Berm Elev. (ft)
100-yr Pond Max Inflow (cfs) (routed)
Length (ft)
Spillway Depth, including 1 ft freeboard (ft)
Spillway Crest Elev. (ft)
1980c WQCV (Current).xls - Pond Summary Page 1 of 6 JVA, Inc.
FCHA - Permanent Supportive Housing
Water Quality Pond and Outlet Sizing (Per USDCM)
Design Engineer:
Design Firm:
Project Number:
Date:
DESIGN CRITERIA:
REQUIRED WATER QUALITY CAPTURE VOLUME (WQCV):
Tributary Area, A 1.9 acres
Composite. Imperviousness, I 46.7%
WQCV (watershed inches) 0.197 inches 40-Hour Drain Time (Fig SQ-2)
Required WQCV 0.038 acre-feet Including 20% for Sedimentation
WATER QUALITY OUTLET SIZING (Per USDCM, Volume 3):
Design Water Quality Depth, DWQ
1.82 ft
Determine K40
K40
= 0.013DWQ
2
+ 0.22DWQ
- 0.10 0.343
Maximum Area per Row, a a = WQCV / K40
0.109 square inches
Number of Rows, nr 5 rows
Number of Columns, nc (See Table 6a-1 for Max.) 1 columns
Choose Hole Diameter 5/16 inches
Use USDCM Volume 3, Figure 5 0.313 inches
Urban Storm Drainage Criteria Manual (USDCM) Volume III, Urban Drainage and Flood Control District, June 2001
Circular Perforation Sizing
D. Harner
JVA, Inc.
2104c
November 20, 2013
* * 1 . 2
12
Area
WQCV
Volume
=
Use USDCM Volume 3, Figure 5 0.313 inches
Total Area per Row, Ao
0.08 square inches
Total Outlet Area, Aot
0.38 square inches
Does design work? Yes
Minimum Steel Plate Thickness 1/4 inch
WQCV.xls - WQCV & Outlet Structure Page 2 of 6 JVA, Inc.
FCHA - Permanent Supportive Housing
Critical Pond Elevations
Design Engineer:
Design Firm:
Project Number:
Date:
DESIGN CRITERIA
Urban Storm Drainage Criteria Manual, Urban Drainage and Flood Control District, June 2001
Stage Storage
Volume (pond volume calculated using the prismoidal formula):
CONTOUR (FT) AREA (FT2) AREA (ACRE)
VOLUME (ACRE-
FT)
DEPTH (FT)
CUMULATIVE VOLUME
(ACRE-FT)
4987.76 0.000 0.000 0.00 0.000
4988.0 81.00 0.002 0.000 0.24 0.000
4989.0 1,005.00 0.023 0.010 1.24 0.011
4990.0 3,253.00 0.075 0.046 2.24 0.057
4991.0 5,206.00 0.120 0.096 3.24 0.153
4991.5 6,121.00 0.141 0.065 3.74 0.218 Spillway
4992.0 7,503.00 0.172 0.078 4.24 0.296
4993.0 9,865.00 0.226 0.199 5.24 0.495 Top of berm
0.038 ac-ft 4989.58 ft
1.82 ft
D. Harner
JVA, Inc.
2104c
Interpolates to an Elev. of
Required Water Quality Capture Volume =
November 20, 2013
Water Quality Volume Pond Detph
( )
3
AAAADepth 1 2 1 2
V
+ +
=
1980c WQCV (Current).xls - Pond Stage Storage #1 Page 3 of 6 JVA, Inc.
1.82 ft
0.233 ac-ft
0.037 ac-ft
0.196 ac-ft 4991.33 ft
3.57 ft
Water Quality Volume Pond Detph
Total Required Detention Volume
Required 100-yr Detention Volume (including WQCV) =
Volume provided w/in Pavers
Total Pond Volume Required
Detention Volume Pond Detph
4987.00
4988.00
4989.00
4990.00
4991.00
4992.00
4993.00
4994.00
0.0 0.1 0.2 0.3 0.4 0.5 0.6
FCHA - Permanent Supportive Housing
Emergency Overflow Spillway Calculations
Design Engineer:
Design Firm:
Project Number:
Date:
Broad-Crested Weir Equation-Trapezoidal Shape
where: Q = Discharge (cfs)
C = Weir Coeffecient
L = Weir Length (ft)
H = Average Weir Head (ft)
H:V =Side Slope
Calculations
Knowns: 4.00
0.50 ft
2.6
4991.50 ft
9.41 cfs *Total Onsite Runnoff
8.24 ft
9 ft
1.50 ft
Side Slopes (H:V)
Desired Spillway Head
Weir Coefficient
Spillway Elevation
D. Harner
JVA, Inc.
2104c
November 20, 2013
100-yr Pond Inflow
Calculated Spillway Length
Use Spillway Length
Spillway Depth
2
5
2
3
H
V
H
QCLH C
= +
Topft of Berm Elevation 4993.0
(including 1' freeboard)
4991.40
4991.60
4991.80
4992.00
4992.20
4992.40
4992.60
4992.80
4993.00
0.00 20.00 40.00 60.00 80.00
ELEVATION (ft)
FCHA - Permanent Supportive Housing
Emergency Overflow Spillway Calculations
Design Engineer:
Design Firm:
Project Number:
Date:
D. Harner
JVA, Inc.
2104c
November 20, 2013
Ponding Depth (ft)
Spillway Head
(ft)
QTotal
(CFS)
4991.50 0.00 0.00
4991.60 0.10 0.77
4991.70 0.20 2.28
4991.80 0.30 4.36
4991.90 0.40 6.97
4992.00 0.50 10.11
4992.10 0.60 13.78
4992.20 0.70 17.97
4992.30 0.80 22.70
4992.40 0.90 27.97
4992.50 1.00 33.80
4992.60 1.10 40.19
4992.70 1.20 47.17
4992.80 1.30 54.72
4992.90 1.40 62.88
4993.00 1.50 71.65
WQCV.xls - Spillway Page 5 of 6 JVA, Inc.
FCHA - Permanent Supportive Housing
Circular Orifice Plate Sizing
Design Engineer:
Design Firm:
Project Number:
Date:
Orifice Equation
where: C = Orifice Discharge Coefficient
A o
= Orifice Area (ft
2
)
g = Gravity (32.2 ft/s
2
)
∆h = Difference in Elevation Head (ft)
D o
= Orifice Diameter (in)
Calculations
100-yr Orifice Sizing 100-yr Orifice Rating Table
Knowns: 100-yr Release Rate 1.13 cfs
100-yr WSEL 4991.33 ft 4987.76 0.68 0.000
4988.00 0.72 0.000
Pond Outlet Invert 4985.56 ft 4989.00 0.86 0.011
4990.00 0.99 0.057
Discharge Coefficient 0.65 4991.00 1.10 0.153
4991.50 1.15 0.218
Tailwater Elevation 4984.68 ft 4992.00 1.20 0.296
4993.00 1.29 0.495
Orifice Diameter 4 2/16 in
Pond Volume
(ac-ft)
D. Harner
JVA, Inc.
2104c
November 20, 2013
Elevation
(ft)
Discharge
(cfs)
C g h
Q
QCA o g h A o ∆
= ∆ ⇒ =
2
2
π
o
o
A
D
= 576
1980c WQCV (Current).xls - Outlet Orifice Plate Sizing Page 6 of 6 JVA, Inc.
Orifice Area 0.092 ft
2
Centroid Elevation 4985.73 ft
Actual Release Rate 1.13 cfs
C g h
Q
QCA o g h A o ∆
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Type of Permeable Pavement Section
A) What type of section of permeable pavement is used?
(Based on the land use and activities, proximity to adjacent
structures and soil characteristics.)
B) What type of wearing course?
2. Required Storage Volume
A) Effective Imperviousness of Area Tributary to Permeable Pavement, Ia Ia = 63.3 %
B) Tributary Area's Imperviousness Ratio (I = Ia / 100) i = 0.633
C) Tributary Watershed Area ATotal = 31,611 sq ft
(including area of permeable pavement system)
D) Area of Permeable Pavement System APPS = 4,518 sq ft
(Minimum recommended permeable pavement area = 7600 sq ft)
E) Impervious Tributary Ratio RT = 3.8 IMPERVIOUS TRIBUTARY RATIO EXCEEDS 2.0
(Contributing Imperviuos Area / Permeable Pavement Ratio)
F) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 522 cu ft
(WQCV = (0.8 * (0.91 * i3 - 1.19 * i2 + 0.78 * i) / 12) * Area)
G) Is flood control volume being added?
Provide overflow to carry runoff directly
into the reservoir layer to ensure use
of flood control volume regardless
FCHA Permanent Supportive Housing
Fort Collins, CO
Design Procedure Form: Permeable Pavement Systems (PPS)
D. Harner
JVAInc.
November 20, 2013
Choose One
No Infiltration
Partial Infiltration Section
Full Infiltration Section
Choose One
YES
NO
Choose One
PICP
Concrete Grid Pavement
Pervious Concrete
Porous Gravel
of flood control volume regardless
H) Total Volume Needed VTotal = 10,136 cu ft of infiltration rates.
3. Depth of Reservoir
A) Minimum Depth of Reservoir Dmin = 16.0 inches
(Minimum recommended depth is 6 inches)
B) Is the slope of the reservoir/subgrade interface equal to 0%?
C) Porosity (Porous Gravel Pavement < 0.3, Others < 0.40) P = 0.40
D) Slope of the Base Course/Subgrade Interface S = 0.010 ft / ft
E) Length Between Lateral Flow Barriers (max = 57.78 ft.) L = 70.0 ft LENGTH TOO LONG
F) Volume Provided Based on Depth of Base Course V = 1,626 cu ft VOLUME PROVIDED <
Flat or Stepped: V = P * ((Dmin-1)/12) * Area TOTAL VOLUME NEEDED
Sloped: V = P * [(Dmin - (Dmin - 6*SL-1)) / 12] * Area Volume assumes uniform slope & lateral flow barrier spacing.
Calculate the volume of each cell individually when this varies.
Choose One
YES- Flat or Stepped Installation
NO- Sloped Installation
APPENDIX B – HYDRAULIC COMPUTATIONS
1. UD-SEWER Report
INLET AT PARKING
MEDIAN
WEST PARKING MEDIAN PLAN VIEW
8" PERF UD
12" STORM DRAIN
TO DETENTION
POND
0.00 17.40 34.80 52.20 69.60 87.00 104.40 121.80 139.20 156.60 174.00
4988.05
4988.85
4989.65
4990.45
4991.25
4992.05
4992.85
4993.65
4994.45
4995.25
HGL
EGL
WEST PARKING MEDIAN STORM PIPE PROFILE
OUTLET TO
DETENTION POND
INLET IN PARKING
MEDIAN
Program:
UDSEWER Math
Model Interface
2.0.3.10
Run Date:
11/20/2013 2:41:04
PM
UDSewer Results Summary
Project Title: FCHA Redtail West Storm System
Project Description: Default system
System Input Summary
Rainfall Parameters
Rainfall Return Period: 100
Rainfall Calculation Method: Formula
One Hour Depth (in): 2.86
Rainfall Constant "A": 28.5
Rainfall Constant "B": 10
Rainfall Constant "C": 0.786
Rational Method Constraints
Minimum Urban Runoff Coeff.: 0.20
Maximum Rural Overland Len. (ft): 500
Maximum Urban Overland Len. (ft): 300
Used UDFCD Tc. Maximum: No
Sizer Constraints
Minimum Sewer Size (in): 18.00
Maximum Depth to Rise Ratio: 0.90
Maximum Flow Velocity (fps): 18.0
Minimum Flow Velocity (fps): 2.0
Backwater Calculations:
Tailwater Elevation (ft): 4991.50
Manhole Input Summary:
Given Flow Sub Basin Information
Element
Name
Ground
Elevation
(ft)
Total
Known
Flow
(cfs)
Local
Contribution
(cfs)
Drainage
Area
(Ac.)
Runoff
Coefficient
5yr
Coefficient
Overland
Length
(ft)
Overland
Slope
(%)
Gutter
Length
(ft)
MH 1 SWR 1
- 1
4994.60 5.30 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
MH 2 SWR 2
- 1
4996.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Manhole Output Summary:
Local Contribution Total Design Flow
Element
Name
Overland
Time
(min)
Gutter
Time
(min)
Basin
Tc
(min)
Intensity
(in/hr)
Local
Contrib
(cfs)
Coeff.
Area
Intensity
(in/hr)
Manhole
Tc
(min)
Peak
Flow
(cfs)
Comment
OUTFALL 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.30
Surface Water Present
(Upstream)
MH 1 SWR 1
- 1
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.30
Surface Water Present
(Downstream)
MH 2 SWR 2
- 1
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.00
Sewer Input Summary:
Elevation Loss Coefficients Given Dimensions
Element
Name
Sewer
Length
(ft)
Downstream
Invert
(ft)
Slope
(%)
Upstream
Invert
(cfs)
MH 1 SWR 1 - 1 5.30 CIRCULAR 12.00 in 12.00 in 18.00 in 18.00 in 12.00 in 12.00 in 0.79
Height is too small.
Width is too small.
Existing height is smaller
than the suggested height.
Existing width is smaller
than the suggested width.
MH 2 SWR 2 - 1 1.00 CIRCULAR 8.00 in 8.00 in 18.00 in 18.00 in 8.00 in 8.00 in 0.35
Height is too small.
Width is too small.
Existing height is smaller
than the suggested height.
Existing width is smaller
than the suggested width.
Calculated diameter was determined by sewer hydraulic capacity rounded up to the nearest commercially available size.
Sewer sizes should not decrease downstream.
All hydraulics where calculated using the 'Used' parameters.
Grade Line Summary:
Tailwater Elevation (ft): 4991.50
Invert Elev.
Downstream
Manhole
Losses
HGL EGL
Element
Name
Downstream
(ft)
Upstream
(ft)
Bend
Loss
(ft)
Lateral
Loss
(ft)
Downstream
(ft)
Upstream
(ft)
Downstream
(ft)
Friction
Loss
(ft)
Upstream
(ft)
MH 1 SWR 1 -
1
4988.77 4991.72 0.00 0.00 4991.50 4993.02 4992.21 1.52 4993.73
MH 2 SWR 2 -
1
4991.92 4992.97 0.17 0.00 4993.77 4994.48 4993.89 0.72 4994.61
Bend and Lateral losses only apply when there is an outgoing sewer. The system outfall, sewer #0, is not considered a
sewer.
Bend loss = Bend K * V_fi ^ 2/(2*g)
Lateral loss = V_fo ^ 2/(2*g)- Junction Loss K * V_fi ^ 2/(2*g).
Friction loss is always Upstream EGL - Downstream EGL.
Excavation Estimate:
MH 2 SWR 2 - 1 105.00 1.67 4.00 3.94 5.69 3.15 1.87 6.39 3.50 2.22 55.44 Sewer Too Shallow
Total earth volume for sewer trenches = 84 cubic yards.
The trench was estimated to have a bottom width equal to the outer pipe diameter plus 36 inches.
If the calculated width of the trench bottom is less than the minimum acceptable width, the minimum acceptable width
was used.
The sewer wall thickness is equal to: (equivalent diameter in inches/12)+1 inches
The sewer bedding thickness is equal to:
Four inches for pipes less than 33 inches.
Six inches for pipes less than 60 inches.
Eight inches for all larger sizes.
UDSEWER Math Model Interface Results: FCHA Redtail West Storm S... file:///V:/1980c Fort Collins Housing Authority/Calculations/Storm Wate...
4 of 4 11/20/2013 2:43 PM
POND OUTLET
STRUCTURE
PIPE OUTFALL TO
EXISTING POND B
DETENTION POND OUTLET PIPING
0.00 14.10 28.20 42.30 56.40 70.50 84.60 98.70 112.80 126.90
4983.47
4984.47
4985.47
4986.47
4987.47
4988.47
4989.47
4990.47
4991.47
4992.47
HGL
EGL
POND OUTLET STORM PROFILE
POND OUTLET
STRUCTURE
PIPE OUTLET
TO EXISTING
POND B
Program:
UDSEWER Math
Model Interface
2.0.3.10
Run Date:
11/22/2013 9:26:20
AM
UDSewer Results Summary
Project Title: FCHA Redtail West Storm System
Project Description: Default system
System Input Summary
Rainfall Parameters
Rainfall Return Period: 100
Rainfall Calculation Method: Formula
One Hour Depth (in): 2.86
Rainfall Constant "A": 28.5
Rainfall Constant "B": 10
Rainfall Constant "C": 0.786
Rational Method Constraints
Minimum Urban Runoff Coeff.: 0.20
Maximum Rural Overland Len. (ft): 500
Maximum Urban Overland Len. (ft): 300
Used UDFCD Tc. Maximum: No
Sizer Constraints
Minimum Sewer Size (in): 15.00
Maximum Depth to Rise Ratio: 0.90
Maximum Flow Velocity (fps): 18.0
Minimum Flow Velocity (fps): 2.0
Backwater Calculations:
Tailwater Elevation (ft): 4984.35
Manhole Input Summary:
Given Flow Sub Basin Information
Element
Name
Ground
Elevation
(ft)
Total
Known
Flow
(cfs)
Local
Contribution
(cfs)
Drainage
Area
(Ac.)
Runoff
Coefficient
5yr
Coefficient
Overland
Length
(ft)
Overland
Slope
(%)
Gutter
Length
(ft)
MH 1 SWR 1
- 1
4993.11 1.13 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
MH 2 SWR 2
- 1
4993.00 1.13 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Manhole Output Summary:
Local Contribution Total Design Flow
Element
Name
Overland
Time
(min)
Gutter
Time
(min)
Basin Tc
(min)
Intensity
(in/hr)
Local
Contrib
(cfs)
Coeff.
Area
Intensity
(in/hr)
Manhole Tc
(min)
Peak
Flow
(cfs)
Comment
OUTFALL 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.13
MH 1 SWR 1 - 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.13
MH 2 SWR 2 - 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.13
Sewer Input Summary:
Elevation Loss Coefficients Given Dimensions
Element
Name
Sewer
Length
(ft)
Downstream
Invert
(ft)
Slope
(%)
Upstream
Invert
(ft)
Mannings
n
Bend
Loss
Lateral
Loss
Cross
Section
Rise
MH 1 SWR 1 - 1 1.13 CIRCULAR 12.00 in 12.00 in 15.00 in 15.00 in 12.00 in 12.00 in 0.79
Height is too small.
Width is too small.
Existing height is smaller
than the suggested height.
Existing width is smaller
than the suggested width.
MH 2 SWR 2 - 1 1.13 CIRCULAR 12.00 in 12.00 in 15.00 in 15.00 in 12.00 in 12.00 in 0.79
Height is too small.
Width is too small.
Existing height is smaller
than the suggested height.
Existing width is smaller
than the suggested width.
Calculated diameter was determined by sewer hydraulic capacity rounded up to the nearest commercially available size.
Sewer sizes should not decrease downstream.
All hydraulics where calculated using the 'Used' parameters.
Grade Line Summary:
Tailwater Elevation (ft): 4984.35
Invert Elev.
Downstream
Manhole
Losses
HGL EGL
Element
Name
Downstream
(ft)
Upstream
(ft)
Bend
Loss
(ft)
Lateral
Loss
(ft)
Downstream
(ft)
Upstream
(ft)
Downstream
(ft)
Friction
Loss
(ft)
Upstream
(ft)
MH 1 SWR 1 -
1
4984.35 4984.81 0.00 0.00 4984.80 4985.31 4984.97 0.47 4985.44
MH 2 SWR 2 -
1
4985.01 4985.23 0.01 0.00 4985.46 4985.73 4985.63 0.23 4985.86
Bend and Lateral losses only apply when there is an outgoing sewer. The system outfall, sewer #0, is not considered a
sewer.
Bend loss = Bend K * V_fi ^ 2/(2*g)
Lateral loss = V_fo ^ 2/(2*g)- Junction Loss K * V_fi ^ 2/(2*g).
Friction loss is always Upstream EGL - Downstream EGL.
Excavation Estimate:
The trench side slope is 1.0 ft/ft
Total earth volume for sewer trenches = 299 cubic yards.
The trench was estimated to have a bottom width equal to the outer pipe diameter plus 36 inches.
If the calculated width of the trench bottom is less than the minimum acceptable width, the minimum acceptable width
was used.
The sewer wall thickness is equal to: (equivalent diameter in inches/12)+1 inches
The sewer bedding thickness is equal to:
Four inches for pipes less than 33 inches.
Six inches for pipes less than 60 inches.
Eight inches for all larger sizes.
UDSEWER Math Model Interface Results: FCHA Redtail West Storm S... file:///V:/1980c Fort Collins Housing Authority/Calculations/Storm Wate...
4 of 4 11/22/2013 9:26 AM
APPENDIX C – REFERENCED INFORMATION
1. Drainage and Erosion Control Report for Redtail
This unofficial copy was downloaded on Jul-18-2013 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
APPENDIX D – UTILITY SITE PLANS
1. Erosion Control Plan (CE1.0)
2. SWMP and Erosion Control Details (CE1.1)
3. Grading and Drainage Plan (C1.0 to C1.3)
4. Storm Drain Plan (C1.4)
5. Drainage Details (CD1.0, CD1.2)
LOT 12
5,340 sq.ft.
5033 FOSSIL BLVD
TRACT I
1,739 sq. ft.
TRACT F
63,458 sq.ft.
1.457 acres
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
678',2&203/(7,9$,1&&23<5,*+7
CIVIL:
MECHANICAL/PLUMBING:
STRUCTURAL:
ARCHITECT:
STUDIO COMPLETIVA
ELECTRICAL:
LANDSCAPE ARCHITECT:
azur ground
JVA
KL&A
MOUNTAIN AIRE
wAyne's ELECTRIC
REDTAIL PONDS PSH
FORT COLLINS
HOUSING AUTHORITY
CE1.0
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
678',2&203/(7,9$,1&&23<5,*+7
CIVIL:
MECHANICAL/PLUMBING:
STRUCTURAL:
ARCHITECT:
STUDIO COMPLETIVA
ELECTRICAL:
LANDSCAPE ARCHITECT:
azur ground
JVA
KL&A
MOUNTAIN AIRE
wAyne's ELECTRIC
REDTAIL PONDS PSH
FORT COLLINS
HOUSING AUTHORITY
CE1.1
LOT 12
5,340 sq.ft.
5033 FOSSIL BLVD
TRACT F
63,458 sq.ft.
1.457 acres
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
678',2&203/(7,9$,1&&23<5,*+7
CIVIL:
MECHANICAL/PLUMBING:
STRUCTURAL:
ARCHITECT:
STUDIO COMPLETIVA
ELECTRICAL:
LANDSCAPE ARCHITECT:
azur ground
JVA
KL&A
MOUNTAIN AIRE
wAyne's ELECTRIC
REDTAIL PONDS PSH
FORT COLLINS
HOUSING AUTHORITY
C1.0
TRACT I
1,739 sq. ft.
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
678',2&203/(7,9$,1&&23<5,*+7
CIVIL:
MECHANICAL/PLUMBING:
STRUCTURAL:
ARCHITECT:
STUDIO COMPLETIVA
ELECTRICAL:
LANDSCAPE ARCHITECT:
azur ground
JVA
KL&A
MOUNTAIN AIRE
wAyne's ELECTRIC
REDTAIL PONDS PSH
FORT COLLINS
HOUSING AUTHORITY
C1.1
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
678',2&203/(7,9$,1&&23<5,*+7
CIVIL:
MECHANICAL/PLUMBING:
STRUCTURAL:
ARCHITECT:
STUDIO COMPLETIVA
ELECTRICAL:
LANDSCAPE ARCHITECT:
azur ground
JVA
KL&A
MOUNTAIN AIRE
wAyne's ELECTRIC
REDTAIL PONDS PSH
FORT COLLINS
HOUSING AUTHORITY
C1.2
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
678',2&203/(7,9$,1&&23<5,*+7
CIVIL:
MECHANICAL/PLUMBING:
STRUCTURAL:
ARCHITECT:
STUDIO COMPLETIVA
ELECTRICAL:
LANDSCAPE ARCHITECT:
azur ground
JVA
KL&A
MOUNTAIN AIRE
wAyne's ELECTRIC
REDTAIL PONDS PSH
FORT COLLINS
HOUSING AUTHORITY
C1.3
LOT 12
5,340 sq.ft.
5033 FOSSIL BLVD
TRACT F
63,458 sq.ft.
1.457 acres
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
678',2&203/(7,9$,1&&23<5,*+7
CIVIL:
MECHANICAL/PLUMBING:
STRUCTURAL:
ARCHITECT:
STUDIO COMPLETIVA
ELECTRICAL:
LANDSCAPE ARCHITECT:
azur ground
JVA
KL&A
MOUNTAIN AIRE
wAyne's ELECTRIC
REDTAIL PONDS PSH
FORT COLLINS
HOUSING AUTHORITY
C1.4
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
678',2&203/(7,9$,1&&23<5,*+7
CIVIL:
MECHANICAL/PLUMBING:
STRUCTURAL:
ARCHITECT:
STUDIO COMPLETIVA
ELECTRICAL:
LANDSCAPE ARCHITECT:
azur ground
JVA
KL&A
MOUNTAIN AIRE
wAyne's ELECTRIC
REDTAIL PONDS PSH
FORT COLLINS
HOUSING AUTHORITY
CD1.0
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
678',2&203/(7,9$,1&&23<5,*+7
CIVIL:
MECHANICAL/PLUMBING:
STRUCTURAL:
ARCHITECT:
STUDIO COMPLETIVA
ELECTRICAL:
LANDSCAPE ARCHITECT:
azur ground
JVA
KL&A
MOUNTAIN AIRE
wAyne's ELECTRIC
REDTAIL PONDS PSH
FORT COLLINS
HOUSING AUTHORITY
CD1.1
C C
A
A
B
B
SECTION C-C
SECTION A-A SECTION B-B
WELL SCREEN FLOW CONTROL PLATE
6"
PLAN
1 GENERAL NOTES
SECTION D-D
WQ
D
A A
OPP.
CLR.
ABBREVIATIONS
@
#
Wp
Wo
TYP.
DIA.
O.C.
MAX.
MIN.
LEGEND
INV. WQ
ELEV.
6"
Ls
Ws
Ws/2 Ws/2
1' Ls 3'-6"
6"
6"
6"
VARIES VARIES
6"
D
6"
4"
Wp
Wo
Wo
1'
Ws
Wo
2'-6"
3"
CLR.
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
CHECKED BY:
Date
Date
Date
Date
Date
Date
City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
Parks and Recreation
Traffic Engineer
Stormwater Utility
Water & Wastewater Utility
City Engineer
CHECKED BY:
APPROVED:
Date
Environmental Planner
678',2&203/(7,9$,1&&23<5,*+7
CIVIL:
MECHANICAL/PLUMBING:
STRUCTURAL:
ARCHITECT:
STUDIO COMPLETIVA
ELECTRICAL:
LANDSCAPE ARCHITECT:
azur ground
JVA
KL&A
MOUNTAIN AIRE
wAyne's ELECTRIC
REDTAIL PONDS PSH
FORT COLLINS
HOUSING AUTHORITY
CD1.2
The minimum trench width is 2.00 ft
Downstream Upstream
Element
Name
Length
(ft)
Wall
(in)
Bedding
(in)
Bottom
Width
(ft)
Top
Width
(ft)
Trench
Depth
(ft)
Cover
(ft)
Top
Width
(ft)
Trench
Depth
(ft)
Cover
(ft)
Volume
(cu. yd)
Comment
MH 1 SWR 1 - 1 95.00 2.00 4.00 4.33 8.84 4.92 3.25 16.60 8.80 7.13 179.71
MH 2 SWR 2 - 1 46.00 2.00 4.00 4.33 16.20 8.60 6.93 15.54 8.27 6.60 119.01
UDSEWER Math Model Interface Results: FCHA Redtail West Storm S... file:///V:/1980c Fort Collins Housing Authority/Calculations/Storm Wate...
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(ft or in)
Span
(ft or in)
MH 1 SWR 1 - 1 95.00 4984.35 0.5 4984.81 0.013 0.03 0.00 CIRCULAR 12.00 in 12.00 in
MH 2 SWR 2 - 1 46.00 4985.01 0.5 4985.23 0.013 0.20 0.00 CIRCULAR 12.00 in 12.00 in
Sewer Flow Summary:
Full Flow Capacity Critical Flow Normal Flow
Element
Name
Flow
(cfs)
Velocity
(fps)
Depth
(in)
Velocity
(fps)
Depth
(in)
Velocity
(fps)
Froude
Number
Flow
Condition
Flow
(cfs)
Surcharged
Length
(ft)
Comment
MH 1 SWR 1 - 1 2.49 3.16 5.37 3.32 5.68 3.09 0.90 Subcritical 1.13 0.00
MH 2 SWR 2 - 1 2.47 3.15 5.37 3.32 5.69 3.08 0.89 Subcritical 1.13 0.00
A Froude number of 0 indicates that pressured flow occurs (adverse slope or undersized pipe).
If the sewer is not pressurized, full flow represents the maximum gravity flow in the sewer.
If the sewer is pressurized, full flow represents the pressurized flow conditions.
Sewer Sizing Summary:
Existing Calculated Used
Element
Name
Peak
Flow
(cfs)
Cross
Section
Rise Span Rise Span Rise Span
Area
(ft^2)
Comment
UDSEWER Math Model Interface Results: FCHA Redtail West Storm S... file:///V:/1980c Fort Collins Housing Authority/Calculations/Storm Wate...
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Gutter
Velocity
(fps)
OUTFALL 1 4988.77 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
UDSEWER Math Model Interface Results: FCHA Redtail West Storm S... file:///V:/1980c Fort Collins Housing Authority/Calculations/Storm Wate...
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The trench side slope is 1.0 ft/ft
The minimum trench width is 2.00 ft
Downstream Upstream
Element
Name
Length
(ft)
Wall
(in)
Bedding
(in)
Bottom
Width
(ft)
Top
Width
(ft)
Trench
Depth
(ft)
Cover
(ft)
Top
Width
(ft)
Trench
Depth
(ft)
Cover
(ft)
Volume
(cu. yd)
Comment
MH 1 SWR 1 - 1 69.00 2.00 4.00 4.33 0.00 0.50 0.00 5.76 3.38 1.71 28.59 Sewer Too Shallow
UDSEWER Math Model Interface Results: FCHA Redtail West Storm S... file:///V:/1980c Fort Collins Housing Authority/Calculations/Storm Wate...
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(ft)
Mannings
n
Bend
Loss
Lateral
Loss
Cross
Section
Rise
(ft or in)
Span
(ft or in)
MH 1 SWR 1 - 1 69.00 4988.77 4.3 4991.72 0.013 1.32 0.00 CIRCULAR 12.00 in 12.00 in
MH 2 SWR 2 - 1 105.00 4991.92 1.0 4992.97 0.013 1.32 0.00 CIRCULAR 8.00 in 8.00 in
Sewer Flow Summary:
Full Flow Capacity Critical Flow Normal Flow
Element
Name
Flow
(cfs)
Velocity
(fps)
Depth
(in)
Velocity
(fps)
Depth
(in)
Velocity
(fps)
Froude
Number
Flow
Condition
Flow
(cfs)
Surcharged
Length
(ft)
Comment
MH 1 SWR 1 - 1 7.39 9.41 11.17 6.96 7.52 10.23 2.46 Pressurized 5.30 69.00
MH 2 SWR 2 - 1 1.21 3.47 5.69 3.76 5.54 3.88 1.06 Pressurized 1.00 105.00
A Froude number of 0 indicates that pressured flow occurs (adverse slope or undersized pipe).
If the sewer is not pressurized, full flow represents the maximum gravity flow in the sewer.
If the sewer is pressurized, full flow represents the pressurized flow conditions.
Sewer Sizing Summary:
Existing Calculated Used
Element
Name
Peak
Flow
Cross
Section
Rise Span Rise Span Rise Span
Area
(ft^2)
Comment
UDSEWER Math Model Interface Results: FCHA Redtail West Storm S... file:///V:/1980c Fort Collins Housing Authority/Calculations/Storm Wate...
2 of 4 11/20/2013 2:43 PM
Gutter
Velocity
(fps)
OUTFALL 1 4988.77 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
UDSEWER Math Model Interface Results: FCHA Redtail West Storm S... file:///V:/1980c Fort Collins Housing Authority/Calculations/Storm Wate...
1 of 4 11/20/2013 2:43 PM
Permeable Pavers UD-BMP_v3.02.xls, PPS 11/20/2013, 8:04 PM
WQCV AVAILABLE IN
ADDITION TO THE
WQCV PROVIDED IN
THE POND
DETENTION VOLUME
UTILIZED IN ADDITION
TO VOLUME IN THE
DETENTION POND.
= ∆ ⇒ =
2
2
π
o
o
A
D
= 576
1980c WQCV (Current).xls - Outlet Orifice Plate Sizing Page 6 of 6 JVA, Inc.
DISCHARGE (cfs)
STAGE - DISCHARGE CURVE FOR THE PROPOSED
DETENTION POND OVERFLOW SPILLWAY FOR SOUTH
POND
WQCV.xls - Spillway Page 4 of 6 JVA, Inc.
ELEVATION (FT)
DETENTION POND VOLUME (AC-FT)
DETENTION POND VOLUME
VERSUS ELEVATION
1980c WQCV (Current).xls - Pond Stage Storage #1 Page 3 of 6 JVA, Inc.
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
0.03 #N/A #N/A #N/A #N/A #N/A #N/A #N/A
Routing 5: Water flows separately through WQCV plate, #1 horizontal opening, #2 horizontal opening, #1 vertical opening, and #2 vertical
opening. The sum of all four will be applied to culvert sheet.
STAGE-DISCHARGE SIZING OF THE WEIRS AND ORIFICES (INLET CONTROL)
Current Routing Order is #5
W.S. EL. WQ
W.S. EL. Minor
W.S. EL. Major
WQ
H1
H2
V1 V2
Routing Order #1 (Standard)
V1
W.S. EL. WQ
W.S. EL. Design Storm
WQ
H1
Routing Order #3 (Single Stage) Routing Order #4
V2
V1
H1
WQ
W.S. EL. Major
W.S. EL. Minor
W.S. EL. WQ
W.S. EL. Emergency Spillway
Emergency Overflow into Pipe- H2
V2
H1
WQ
W.S. EL. Major
W.S. EL. Minor
W.S. EL. WQ V1
Routing Order #2
UD-Detention_v2.33 (2-yr release WEST).xls, Outlet 11/20/2013, 8:13 PM
120 0.51 0.051 0.54 0.61 0.101 -0.050 120 1.77 0.334 0.54 0.61 0.101 0.233
125 0.49 0.052 0.54 0.61 0.105 -0.053 125 1.72 0.337 0.54 0.61 0.105 0.233
130 0.48 0.052 0.54 0.61 0.109 -0.057 130 1.67 0.341 0.54 0.61 0.109 0.232
135 0.47 0.053 0.54 0.61 0.113 -0.060 135 1.63 0.345 0.54 0.61 0.113 0.232
140 0.45 0.053 0.54 0.60 0.117 -0.063 140 1.58 0.348 0.54 0.60 0.117 0.231
145 0.44 0.054 0.53 0.60 0.121 -0.067 145 1.54 0.351 0.53 0.60 0.121 0.231
150 0.43 0.054 0.53 0.60 0.124 -0.070 150 1.50 0.354 0.53 0.60 0.124 0.230
155 0.42 0.055 0.53 0.60 0.128 -0.074 155 1.47 0.357 0.53 0.60 0.128 0.229
160 0.41 0.055 0.53 0.60 0.132 -0.077 160 1.43 0.360 0.53 0.60 0.132 0.228
165 0.40 0.056 0.53 0.60 0.136 -0.081 165 1.40 0.363 0.53 0.60 0.136 0.227
170 0.39 0.056 0.53 0.60 0.140 -0.084 170 1.37 0.366 0.53 0.60 0.140 0.226
175 0.38 0.056 0.53 0.60 0.144 -0.087 175 1.34 0.369 0.53 0.60 0.144 0.225
180 0.38 0.057 0.53 0.60 0.148 -0.091 180 1.31 0.371 0.53 0.60 0.148 0.224
185 0.37 0.057 0.53 0.60 0.152 -0.094 185 1.29 0.374 0.53 0.60 0.152 0.222
190 0.36 0.058 0.53 0.59 0.156 -0.098 190 1.26 0.377 0.53 0.59 0.156 0.221
195 0.35 0.058 0.53 0.59 0.159 -0.101 195 1.24 0.379 0.53 0.59 0.159 0.220
200 0.35 0.058 0.52 0.59 0.163 -0.105 200 1.21 0.381 0.52 0.59 0.163 0.218
205 0.34 0.059 0.52 0.59 0.167 -0.109 205 1.19 0.384 0.52 0.59 0.167 0.217
210 0.34 0.059 0.52 0.59 0.171 -0.112 210 1.17 0.386 0.52 0.59 0.171 0.215
215 0.33 0.059 0.52 0.59 0.175 -0.116 215 1.15 0.388 0.52 0.59 0.175 0.213
220 0.32 0.060 0.52 0.59 0.179 -0.119 220 1.13 0.391 0.52 0.59 0.179 0.212
225 0.32 0.060 0.52 0.59 0.183 -0.123 225 1.11 0.393 0.52 0.59 0.183 0.210
230 0.31 0.060 0.52 0.59 0.187 -0.126 230 1.09 0.395 0.52 0.59 0.187 0.208
235 0.31 0.061 0.52 0.59 0.191 -0.130 235 1.08 0.397 0.52 0.59 0.191 0.206
240 0.30 0.061 0.52 0.59 0.194 -0.133 240 1.06 0.399 0.52 0.59 0.194 0.205
245 0.30 0.061 0.52 0.59 0.198 -0.137 245 1.04 0.401 0.52 0.59 0.198 0.203
250 0.29 0.062 0.52 0.59 0.202 -0.141 250 1.03 0.403 0.52 0.59 0.202 0.201
255 0.29 0.062 0.52 0.59 0.206 -0.144 255 1.01 0.405 0.52 0.59 0.206 0.199
260 0.29 0.062 0.52 0.59 0.210 -0.148 260 1.00 0.407 0.52 0.59 0.210 0.197
265 0.28 0.063 0.52 0.59 0.214 -0.151 265 0.98 0.409 0.52 0.59 0.214 0.195
270 0.28 0.063 0.52 0.59 0.218 -0.155 270 0.97 0.411 0.52 0.59 0.218 0.193
275 0.27 0.063 0.52 0.59 0.222 -0.159 275 0.96 0.412 0.52 0.59 0.222 0.191
280 0.27 0.063 0.52 0.59 0.226 -0.162 280 0.94 0.414 0.52 0.59 0.226 0.189
285 0.27 0.064 0.52 0.58 0.230 -0.166 285 0.93 0.416 0.52 0.58 0.230 0.187
290 0.26 0.064 0.52 0.58 0.233 -0.170 290 0.92 0.418 0.52 0.58 0.233 0.184
295 0.26 0.064 0.52 0.58 0.237 -0.173 295 0.91 0.419 0.52 0.58 0.237 0.182
300 0.26 0.064 0.52 0.58 0.241 -0.177 300 0.89 0.421 0.52 0.58 0.241 0.180
Mod. FAA Minor Storage Volume (cubic ft.) = 175 Mod. FAA Major Storage Volume (cubic ft.) = 10,136
Mod. FAA Minor Storage Volume (acre-ft.) = 0.0040 Mod. FAA Major Storage Volume (acre-ft.) = 0.2327
DETENTION VOLUME BY THE MODIFIED FAA METHOD
FCHA - PSH
A1 AND A2 ROUTED TO POND
Determination of MAJOR Detention Volume Using Modified FAA Method
(For catchments less than 160 acres only. For larger catchments, use hydrograph routing method)
(NOTE: for catchments larger than 90 acres, CUHP hydrograph and routing are recommended)
UDFCD DETENTION BASIN VOLUME ESTIMATING WORKBOOK Version 2.33, Released August 2013
Determination of MINOR Detention Volume Using Modified FAA Method
UD-Detention_v2.33 (2-yr release WEST).xls, Modified FAA 11/20/2013, 8:13 PM
20 2.0 1.8 5.8 264 11.5 5.8
A2 2 1.17 0.53 100 2.0% 8.3 330 2.0% Grassed waterway 15 2.1 2.6 10.9 430 12.4 10.9
A3 3 0.22 0.34 74 3.0% 8.3 75 25.0% Short Pasture and lawns 7 3.5 0.4 8.6 149 10.8 8.6
A4 4 0.70 0.37 100 2.0% 10.7 255 6.0% Short Pasture and lawns 7 1.7 2.5 13.2 355 12.0 12.0
Initial Overland Time (ti
)
Travel Time (tt
)
tt
=Length/(Velocity x 60)
tc Urbanized Check
ON
1980c - Rational Calculations.xlsx Developed Tc Page 3 of 5
Velocity
(fps)
tt
(min)
Time of
Conc
ti + tt = tc
Total
Length
(ft)
tc=(L/180)+
10 (min.)
Min
tc
H1 1 751 0 0 417 0 0 6,900 0 8,068 0.19 13.1% 0.33 0.33 0.33 0.39 50 4.0% 6.3 50 4.0% Nearly bare ground 10 2.0 0.4 6.7 100 10.6 6.7
H2 2 0 0 0 0 0 0 8,270 0 8,270 0.19 2.0% 0.25 0.25 0.25 0.31 45 4.0% 6.6 45 4.0% Nearly bare ground 10 2.0 0.4 7.0 90 10.5 7.0
H3 3 0 0 0 0 0 3,382 3,846 32,494 39,722 0.91 2.0% 0.33 0.33 0.33 0.41 110 2.0% 11.8 490 10.0% Nearly bare ground 10 3.2 2.6 14.4 600 13.3 13.3
H4 4 0 0 0 0 0 11,701 40,517 19,503 71,721 1.65 2.0% 0.27 0.27 0.27 0.34 130 1.5% 15.2 400 10.0% Nearly bare ground 10 3.2 2.1 17.3 530 12.9 12.9
Routed Together
H1+H2 1 751 0 0 417 0 0 15,170 0 16,338 0.38 7.5% 0.29 0.29 0.29 0.35 50 4.0% 6.6 50 4.0% Nearly bare ground 10 2.0 0.4 7.0 100 10.6 7.0
H3+H4 4 0 0 0 0 0 15,083 44,363 51,997 111,443 2.56 2.0% 0.29 0.29 0.29 0.36 110 2.0% 12.4 540 10.0% Nearly bare ground 10 3.2 2.8 15.2 650 13.6 13.6
TOTAL SITE 751 0 0 417 0 15,083 59,533 51,997 127,781 2.93 2.7% 0.29 0.29 0.29 0.36
Initial Overland Time (ti)
ti=0.395(1.1-C5)L1/2S-1/3
Travel Time (tt) tt=Length/(Velocity
x 60)
tc Urbanized Check
ON
Runoff Coeff's
I = (28.5 P1) / ((10 + TC) 0.786651)
Basin
Name
Design
Point
Time of
Conc
(tc)
C2 C5 C10 C100 2 5 10 100 ATotal (sf)
ATotal
(ac)
Q2 Q5 Q10 Q100
2-YR
CFS/A
C
H1 1 6.7 0.33 0.33 0.33 0.39 2.55 3.55 4.36 8.90 8,068 0.19 0.16 0.22 0.26 0.65 0.84
H2 2 7.0 0.25 0.25 0.25 0.31 2.52 3.50 4.30 8.78 8,270 0.19 0.12 0.17 0.20 0.52 0.63
H3 3 13.3 0.33 0.33 0.33 0.41 1.97 2.73 3.35 6.85 39,722 0.91 0.59 0.82 1.00 2.56 0.64
H4 4 12.9 0.27 0.27 0.27 0.34 1.99 2.77 3.40 6.94 71,721 1.65 0.88 1.23 1.51 3.84 0.54 Developed release rate for basin A1 and A2
TOTAL SITE 127,781 2.93 1.75 2.42 2.98 7.57 0.60 1.13 cfs
WESTERN Basins H1 & H2 Routed Together
H1+H2 1 7.0 0.29 0.29 0.29 0.35 2.52 3.50 4.30 8.78 16,338 0.38 0.27 0.38 0.46 1.16
EASTERN Basins H3 & H4 Routed Together
H3+H4 4 13.6 0.29 0.29 0.29 0.36 1.95 2.70 3.32 6.78 111,443 2.56 1.44 2.00 2.46 6.29
Runoff Coeff's Rainfall Intensities (in/hr) Area Flow Rates (cfs)
1980c - Rational Calculations.xlsx Historic Page 1 of 5
Survey Area Data: Version 7, May 1, 2009
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—Nov 18,
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.
Hydrologic Soil Group—Larimer County Area, Colorado
(Fort Collins Housing Authority)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/18/2013
Page 2 of 4