HomeMy WebLinkAboutMONTAVA - PHASE G & IRRIGATION POND - BDR210013 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT
Montava – Phase G PDP
Preliminary Drainage Report
Fort Collins, Colorado
Martin/Martin, Inc. Project No.: 19.1354
December 14, 2021
Prepared For: HF2M Colorado
430 North College Avenue, Suite 410
Fort Collins, Colorado 80524
512.507.5570
Attn: Max Moss
Prepared By: MARTIN/MARTIN, INC.
12499 WEST COLFAX AVENUE
LAKEWOOD, COLORADO 80215
303.431.6100
Principal-in-Charge: Peter Buckley
Project Manager: Jeff White
Project Engineer: Ryan Byrne
Project Engineer: Josh Dickerson
Project Engineer: Evan Bednar
TABLE OF CONTENTS
I. General Location and Existing Site Information...........................................................................................1
A. General Description .................................................................................................................................1
B. Location ....................................................................................................................................................1
C. Existing Facilities ......................................................................................................................................2
II. Master Drainage Basin Description..............................................................................................................2
A. Cooper Slough Watershed .......................................................................................................................2
B. Nearby Masterplan improvements ..........................................................................................................3
III. Floodplain Information ................................................................................................................................4
IV. Proposed Drainage Facilities ........................................................................................................................5
A. Drainage Plan ...........................................................................................................................................5
B. Water Quality and Detention ...................................................................................................................7
C. Low Impact Development (LID) ...............................................................................................................8
D. Ownership and Maintenance ...................................................................................................................8
V. Drainage Design Criteria ..............................................................................................................................9
A. Previous studies .......................................................................................................................................9
B. MDCIA “Four Step Process” .....................................................................................................................9
C. Hydrologic Criteria ................................................................................................................................ 10
VI. Variance Requests ..................................................................................................................................... 10
VII. Erosion Control ......................................................................................................................................... 10
VIII. Conclusion ................................................................................................................................................. 11
A. Compliance ........................................................................................................................................... 11
B. Drainage Concept .................................................................................................................................. 11
REFERENCES ...................................................................................................................................................... 12
APPENDICES
A- Supporting Documents
B- Hydrologic Calculations
C- WQ/Detention Calculations
D- LID Calculations
E- Drainage Plans
I. General Location and Existing Site Information
A. General Description
The proposed PROJECT will include new construction of a 35.8 acre Traditional Neighborhood
Development (TND) in northeast Fort Collins. It is planned as a mixed-density neighborhood
including approximately 200 units of townhomes, duplexes, cottages, and small- and medium-
single family homes. The multi-family areas (anticipated at approximately 160 units) will be
included in the overall planning for this area and will be platted as parcels for future
development but are not planned to be included for review at this time.
B. Location
Section Township Range, vicinity map, nearby developments, master drainage basin
The Development is located in southwest quarter of Section 32, Township 8 North, Range 68
West of the 6th Principal Meridian, Larimer County, City of Fort Collins, Colorado. The property is
bordered by the Storybrook Subdivision to the west, City of Fort Collins property to the north,
the No. 8 Ditch and future Montava Phase E and H to the east, and farm land and Mountain
Vista Dr. to the south A vicinity map is provided in Figure 1.
Figure 1: Montava Phase G Vicinity Map
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C. Existing Facilities
The existing Phase G site area is undeveloped and farmed land located within the Cooper Slough
watershed. A storm drainage pond and conveyance exist along the southwestern portion of the
site servicing Storybrook and will be reconfigured as part of the Phase G development plan. An
existing Low Impact Development (LID) linear bioretention swale servicing Storybrook is located
within a drainage easement that runs along the westerly boundary of the Phase G site and will
not be impacted by the proposed improvements. No trees exist on this property with the
exception of a line of younger trees planted along the west property boundary. The No. 8 canal
exists along the east edge of the property and will be reconfigured and improved adjacent to
Phase G. All or part of this section of the No. 8 canal is expected be piped to accommodate the
planned Timberline Road extension north of Mountain Vista Drive and to work with the planned
development in this area.
According to the Natural Resources Conservation Service Web Soil Survey, existing soils on site
are predominately defined as Stoneham loam, classified as Hydrologic Soil Group B and C, which
are soils having a relatively slow infiltration rate when thoroughly wet. According to the
Preliminary Subsurface Exploration Report for the overall Montava Development, by Earth
Engineering Consultants, LLC, groundwater depths on and adjacent to the site are greater than
10 feet.
II. Master Drainage Basin Description
A. Cooper Slough Watershed
The Development is located within the lower portion of the Cooper Slough Watershed. The
Cooper Slough drainage basin resides in northeast Fort Collins and unincorporated Larimer
County, Colorado. It is a long and slender watershed, flowing from north to south, comprising
28 square miles which are tributary to Box Elder Creek and the Cache la Poudre River. The
watershed begins at the confluence with Box Elder Creek (about one-half mile south of Mulberry
Street and slightly west of I-25) and proceeds north for 20-miles to Larimer County Road 80 at a
location northwest of the Town of Wellington. The basin has a maximum width of 3.9-miles at a
location just south of Wellington. Predominant land uses are characterized by farmland and
open space, with development occurring mainly in the southern portion of the watershed, near
northeast Fort Collins.
The Cooper Slough watershed can be divided into upper and lower portions by the Larimer &
Weld Canal (L&W Canal) which transects the basin from west to east and intercepts natural and
man-made drainages. Upper Cooper Slough is significantly larger than the Lower Cooper basin,
at 26.4 sq.-miles and 2.3 sq.-miles respectively. There are three primary drainage paths in
Upper Copper Slough, which flow from north to south. The western most flow path is the
Number 8 Outlet Ditch (No. 8 Ditch) which carries both storm and irrigation flows. It has been
noted in previous studies that the capacity of this ditch is “severely limited” (ACE 2006) and is in
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need of improvements, which will be implemented for the reach of the No. 8 Ditch through The
Development. In addition to the irrigation and drainage ditches, four (4) significant irrigation
reservoirs exist in the upper watershed. These include the North Poudre Reservoirs Nos. 2, 5,
and 6 and the Windsor Reservoir No. 8.
Since the L&W Canal captures flows from the entire upper watershed there are multiple
locations, in multiple watersheds, where storm flows will spill from the canal. In the Cooper
Slough basin, the most notable spill is in the Waterglen development area at the upper end of
the historic Cooper Slough channel. This side spill is located at the primary outfall location from
The Development. A vicinity map of the Cooper Slough watershed is provided in Figure 2.
Figure 2: Cooper Slough Watershed Vicinity Map
B. Nearby Masterplan improvements
The Upper Cooper Slough Selected Plan was developed in 2017 by ICON Engineering, Inc.
(ICON). Prior to the 2017 report, an alternative analysis update on the Upper Cooper Slough
basin was also performed by ICON (Cooper Slough, Alternative Analysis Update, 2017). The
alternative analysis recommended drainage improvements and development criteria for the
Upper Cooper Slough Basin. The purpose of the 2017 Selected Plan report was to summarize the
recommendations in the alternative analysis study and to update the previous Selected Plan for
the basin (Anderson Consulting Engineers, 2006). The improvements recommended in the 2006
Selected Plan were modified in 2017 to reflect updates in hydrology and upcoming
development; however, the main goals for the improvements were not changed.
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The 2017 Selected Plan improvement recommendations included:
1. North Poudre Reservoir No. 6 – Outlet Sill
2. Sod Farm Detention Pond and No. 8 Outlet Ditch Spill
3. Mountain Vista Diversion on No. 8 Outlet Ditch (to C&S Pond)
4. Removal of C&S RR Flow Split (C&S RR Railroad Diversion)
5. Crumb and C&S RR Regional Detention Pond
6. AB Detention Pond Improvements
7. Culvert Improvements at:
a. Vine Drive Crossing
b. Mulberry Street (SH-14)
c. Mountain Vista Culvert – East flow path
d. Mountain Vista Culvert – West flow path
8. Bank and Habitat Improvements
In addition to including the selected plan improvements, site specific development criteria for
the Mountain Vista and Anheuser Busch (Montava) areas were recommended. Since the
creation of the selected plan there have been several potential developments forthcoming in
the Upper Cooper Slough Basin. These developments are in areas that have potential impacts to
the selected plan improvements.
The No. 8 Ditch runs south through the Cooper Slough watershed. It is modeled in EPA SWMM
as a constant flow hydrograph. The 2017 Selected Plan utilized a constant decreed flow of
125cfs for the No. 8 Ditch. Following a meeting on March 11, 2020, the Larimer and Weld
Irrigation Company (LWIC), who represents both the No. 8 Ditch and LWC, have updated the
decreed/maximum flows for both the Larimer and Weld and the No. 8 Ditch to be considered
with the selected plan updates. The LWIC determined that the following two scenarios would
need to be considered in planning and collaboration with the ongoing development:
A. No. 8 Ditch maximum flow of 250cfs with a maximum flow of 675cfs in the LWC; and:
B. LWC conveying a decreed flow of 800cfs, with the No. 8 Ditch not contributing.
These changes in flow have shown to impact the improvements proposed in the 2017 Selected
Plan and subsequent development collaboration. ICON subsequently updated the Cooper
Slough EPA SWMM model to incorporate the updated decreed flows within the No. 8 Ditch and
LWC. The model was revised by Martin/Martin, Inc. as it relates to the Montava development
and was used as the basis for analysis of the Phase G interim conditions Master Plan as defined
in this report.
III. Floodplain Information
A FEMA regulatory Floodplain has not been mapped for the Cooper Slough drainageway through the
Montava development. As a result, coordination with FEMA through the Letter of Map Change
process is not required as a condition of development within Montava, including Phase G. Although
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a Special Flood Hazard Area (SFHA) has not been identified, there is the potential for surface
flooding along the No. 8 Ditch corridor, which will be considered in the design of Phase G to verify
there a no adverse impacts to existing or proposed insurable structures or adjacent properties.
IV. Proposed Drainage Facilities
A. Drainage Plan
Montava Phase G has been broken up into three major basins based on the proposed receiving
water quality and detention facility. The northerly portion of the site makes up Basin 2 and
drains to Pond E, located at the northeast corner of the property. The central portion of the site
makes up Basin 3 and drains to Pond A2 located west of the proposed multifamily parcel
between Road C and Road F. The southerly portion of the site makes up Basin 4 and drains to
Pond A1, located adjacent to Mountain Vista Drive. These three facilities will provide flood
control detention and water quality treatment for Phase G and the tributary portions of
Mountain Vista Drive and Timberline Road prior to discharging to the improved No. 8 Ditch,
which will be piped along the easterly boundary of the development. The following outlines the
specific drainage plan for the three major drainage basins.
Basin 2
Basin 2 is made up of mixed density single family lots, roadways, greenways which will serve as
LID features, and water quality and detention Pond E. The basin is approximately 14.8 acres
(including the tributary portion of Timberline Road), with a composite imperviousness equal to
roughly 70%. Generally, storm runoff from the single family lots will be conveyed to the street
section curb and gutter, which will convey concentrated flows to curb inlets connecting to a
storm sewer system that will discharge to linear bioretention swales. The street, inlet, and storm
sewer system will be sized based on the minor 2-year and major 100-year storm events, with a
combined surface and sub-surface conveyance approach based on the constraints of the
roadway section. At roadway sump locations, both the minor and major storms will be collected
and conveyed in the sub-surface storm sewer system.
There are a total of two linear bioretention swales within Basin 2. The first is located offsite
within the existing City of Fort Collins property along the northerly boundary of Phase G. The
second linear bioretention swale is located on-site adjacent to the Timberline Road Right-Of-
Way. After being treated in the linear bioretention swales, storm flows will discharge into water
quality and detention Pond E, which will provide residual water quality treatment outside of
what is being treated via LID components and will attenuate runoff to a maximum discharge
equal to the corresponding historic 2-year release rate tributary to the facility. Pond E ultimately
discharges to the piped improvements to the No. 8 Ditch, which has historically accepted storm
runoff from the property. Note there a no offsite discharges to Basin 2.
Basin 3
Basin 3 is made up of mixed density single family lots, roadways, greenways which will serve as
LID features, and water quality and detention Pond A2. The basin is approximately 14.5 acres,
with a composite imperviousness equal to roughly 68%. Generally, storm runoff from the single
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family lots will be conveyed to the street section curb and gutter, which will convey
concentrated flows to curb inlets connecting to a storm sewer system, which ultimately
discharges to Pond A2 located south of Road A between Road C and Road F, west of the
proposed multi-family parcel. The street, inlet, and storm sewer system will be sized based on
the minor 2-year and major 100-year storm events, with a combined surface and sub-surface
conveyance approach based on the constraints of the roadway section. At roadway sump
locations, both the minor and major storms will be collected and conveyed in the sub-surface
storm sewer system.
A portion of Basin 3 will be conveyed to bioretention raingardens located adjacent to single
family lots between Alley 5 and Alley 6, Alley 1 and Alley 12, Alley 2 and Alley 14, and Alley 3 and
Pond A2. After being treated in the bioretention raingardens, storm flows will discharge into
water quality and detention Pond A2, which will provide residual water quality treatment
outside of what is being treated via LID components and will attenuate runoff to a maximum
discharge equal to the corresponding historic 2-year release rate tributary to the facility. Pond
A2 ultimately discharges to the piped improvements to the No. 8 Ditch, which has historically
accepted storm runoff from the property. Note there a no offsite discharges to Basin 3.
Basin 4
Basin 4 is made up of mixed density single family lots, the proposed multi-family parcel,
roadways, greenways which will serve as LID features, and water quality and detention Pond A1.
The basin is approximately 10.3 acres (including the tributary portion of Mountain Vista Drive),
with a composite imperviousness equal to roughly 61%. Generally, storm runoff from the single
family lots will be conveyed to the street section curb and gutter, which will convey
concentrated flows to curb inlets connecting to a storm sewer system that will discharge to a
combined linear bioretention swale and detention facility located along the southerly boundary
of Phase G adjacent to Mountain Vista Drive. The street, inlet, and storm sewer system will be
sized based on the minor 2-year and major 100-year storm events, with a combined surface and
sub-surface conveyance approach based on the constraints of the roadway section. At roadway
sump locations, both the minor and major storms will be collected and conveyed in the sub-
surface storm sewer system.
The narrow linear configuration of Pond A1 lends itself to providing residence time consistent
with typical linear LID water quality features, providing conveyance and infiltration of the water
quality event over the length of the facility. Storm events in excess of the water quality event
will be controlled by an outlet orifice designed to attenuate runoff to a maximum discharge
equal to the corresponding historic 2-year release rate tributary to the facility. Pond A1
ultimately discharges to the piped improvements to the No. 8 Ditch, which has historically
accepted storm runoff from the property. An existing water quality and detention pond located
at the southeast corner of the Storybrook Subdivision discharges to Phase G through a 24-inch
storm sewer. Phase G of the Montava development is proposing to pipe the offsite runoff from
the Storybrook subdivision directly to the piped improvements to the No. 8 Ditch to avoid
combining the treated flows from that development with the proposed linear bioretention
swale treating Phase G. This will allow both the LID and detention features to be considered
offline facilities, which will simplify the overall design.
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B. Water Quality and Detention
As discussed, there are a total of three water quality and detention facilities proposed for Phase
G of the Montava development, Ponds E, A1, and A2. Details of these facilities are outlined
below.
Pond E
Pond E has been preliminarily sized to provide the full Water Quality Control Volume (WQCV)
and 100-year detention volume for Basin 2. The full WQCV has been initially included as a
conservative approach, knowing that the proposed LID features will allow for reduction of the
required WQCV. Sizing of the facility was accomplished using the City of Fort Collins imperial
WQCV equation coupled with routing the water quality and 100-year storm events through the
facility using EPA SWMM. A stage-storage-discharge relationship was developed for the pond
based on the preliminary grading and outlet structure configuration. A 40-hour drain time was
targeted for the water quality event, and the historic 2-year discharge was targeted for the 100-
year event. EPA SWMM was also used to verify drain times to show compliance with Colorado
Revised Statute 37-92-602(8).
Pond E will have a single inflow point from the proposed LID linear bioretention swale north of
the proposed facility. A hard bottom forebay will be constructed at the outfall point and a 2-foot
width concrete trickle channel will connect the forebay to the outlet structure along the bottom
of the bond. The outlet structure will consist of a Type-C inlet with a notched opening, well
screen, and orifice plate to control the water quality event. Storm events in excess of the water
quality event will enter the grate opening of the inlet and enter an outfall pipe to the improved
No. 8 Ditch piped segment controlled with a restrictor plate. Maintenance access will be
provided to the forebay and outlet structure via a crusher fines path.
Pond A2
Pond A2 has been preliminarily sized to provide the full Water Quality Control Volume (WQCV)
and 100-year detention volume for Basin 3. The full WQCV has been initially included as a
conservative approach, knowing that the proposed LID features will allow for reduction of the
required WQCV. Sizing of the facility was accomplished using the City of Fort Collins imperial
WQCV equation coupled with routing the water quality and 100-year storm events through the
facility using EPA SWMM. A stage-storage-discharge relationship was developed for the pond
based on the preliminary grading and outlet structure configuration. A 40-hour drain time was
targeted for the water quality event, and the historic 2-year discharge was targeted for the 100-
year event. EPA SWMM was also used to verify drain times to show compliance with Colorado
Revised Statute 37-92-602(8).
Pond A2 will have a total of three inflow points. Two from a portion of the basin not treated via
LID and a third from the proposed bioretention raingardens located within the green spaces
near the southerly end of the basin. Hard bottom forebays will be constructed at the outfall
points and 2-foot width concrete trickle channels will connect the forebays to the outlet
structure along the bottom of the bond. The outlet structure will consist of a Type-C inlet with a
notched opening, well screen, and orifice plate to control the water quality event. Storm events
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in excess of the water quality event will enter the grate opening of the inlet and enter an outfall
pipe to the improved No. 8 Ditch piped segment controlled with a restrictor plate. Maintenance
access will be provided to the forebays and outlet structure via a crusher fines path.
Pond A2 is being considered an amenity pond with a park terrace vertically positioned to be
outside the 10-year water surface elevation within the facility.
Pond A1
Pond A1 will provide LID linear bioretention treatment and flood control detention for Basin 4.
The hybrid facility is long and narrow and provides an opportunity to treat the water quality
event with a low-impact approach. The facility will be constructed with a grass lined bottom and
underdrain to promote infiltration and biologic uptake. Storms in excess of the water quality
event will be control by a restrictor plate over the outfall pipe connected to the improved No. 8
Ditch piped segment. Sizing of the flood control component of the facility was accomplished
using by routing the 100-year storm event through the facility using EPA SWMM. A stage-
storage-discharge relationship was developed for the pond based on the preliminary grading
and outlet configuration. The historic 2-year discharge was targeted for the 100-year event. EPA
SWMM was also used to verify drain times to show compliance with Colorado Revised Statute
37-92-602(8).
Pond A1 will have four inflow points, one at Road B, one at Road C, an outfall from Timberline
Road, and an outfall from Mountain Vista Drive. The outlet will consist of a trash rack and
restrictor plate over an outfall pipe connected the improved No. 8 Ditch piped segment.
Maintenance access will be provided along the length of the linear bioretention feature and to
the outlet.
C. Low Impact Development (LID)
Per City of Fort Collins criteria, Low Impact Development (LID) features are proposed to treat
75% of the newly developed area within Phase G, excluding the proposed multi-family parcel,
which will require on-site LID systems upon development. Note that the Mountain Vista Drive
and Timberline Right-Of-Way Adjacent to Phase G is discharging to the proposed LID systems
and was included in the overall treatment percentage.
Two LID systems are being proposed for Phase G within the Montava Development,
Bioretention (Rain Gardens), and Linear Bioretention. The location of these systems is described
in Section IV.B. Calculations showing the percentage of newly developed area treated by these
systems is included in the Appendix.
D. Ownership and Maintenance
The proposed LID systems and water quality and detention facilities will be located in common
tracts owned and maintained by the Montava Metropolitan District.
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V. Drainage Design Criteria
A. Previous studies
The proposed Phase G improvements have been analyzed and designed to be in compliance
with the Montava Planned Unit Development (PUD) Master Drainage Study, by Martin/Martin,
Inc., dated January 23, 2019.
B. MDCIA “Four Step Process”
Step 1 – Employ Runoff Reduction Practices
Montava Phase G is providing LID treatment for 75% of the site (excluding the multifamily
parcel) through the implementation of Bioretention (Rain Gardens) and Linear Bioretention
Swales. The LID systems have been strategically placed throughout the development to
minimized directly connected impervious areas.
Step 2 – Implement BMPs That Provide a WQCV with Slow Release
The remaining 25% of the site not tributary to LID feature is being treated through traditional
water quality control volume extended detention basins designed to release the water quality
event in a minimum of 40 hours.
Step 3 – Stabilize Streams
Phase G of Montava will improve the receiving drainageway, the No. 8 Ditch, by piping the reach
adjacent to the easterly boundary of the development. Piping the ditch has been identified by
the ditch owner as preferred solution to minimize public interaction with the existing facility.
Piping the ditch will help to minimize sediment loads within the open irrigation channel
downstream of Phase G.
Step 4 – Implement Site Specific and Other Source Control BMPs
The following practices suggested by City of Fort Collins criteria will be employed throughout the
design and construction process.
· Being a single family development, trash receptacles will be dispersed throughout the
neighborhood and likely be enclosed containers that minimize concentrated and
polluted runoff from entering the storm sewer system or receiving drainageway prior to
being treated. The future single-family parcel shall locate trash collection or enclosure
areas away from storm drainage or LID facilities.
· Phase G of Montava does not include dog parks. But, any future dog parks shall be
located in areas away from detention basins and educational opportunities to reinforce
pick-up practices for dog owners shall be employed.
· Phase G of Montava does not include any community gardens. But, future community
gardens shall be located in areas that are outside of detention basins to prevent
chemical and sediment loading.
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· Construction Best Management Practices (BMPs) will be employed to located material
storage away from drainage facilities.
C. Hydrologic Criteria
Per City of Fort Collins stormwater criteria, the 2-year and 100-year recurrence interval storms
were analyzed for the minor and major events, respectively. The 2-year storm will be conveyed
in the street section curb and gutter in a manner that minimizes inconvenience during more
frequently occurring storms. The 100-year storm event will also be conveyed in the street
section within City of Fort Collins depth and spread criteria, with curb inlets placed to intercept
flows, as needed. At sump locations both the minor and major storm events will be fully
captured and introduced to the proposed storm sewer system.
For street, inlet, and storm sewer design, the rational method is being used to estimate peak
flows values, with runoff coefficients per City of Fort Collins criteria based on surface type. Time
of concentration was estimated based on a maximum 200-foot overland flow length and
channelized flow time based on Manning’s Equation. Intensity values were estimated using the
Fort Collins Rainfall Intensity-Duration-Frequency curves.
The water quality control volume requirements were calculated based on City of Fort Collins
Equation 7-1 targeting a drain time of 40 hours. The water quality event was routed through the
proposed detention facilities in SWMM with a rainfall distribution based on a 0.6 inch one-hour
rainfall depth consistent with regional water quality events.
To stay consistent with the Montava PUD Master Drainage Plan, detention volumes were
calculated using EPA SWMM with stage-storage-discharge relationships based on conceptual
grading and outlet configuration. The historic 2-year release rate was targeted as the maximum
discharge for the 100-year storm event. The City of Fort Collins Intensity-Duration-Frequency
Curves for SWMM were used for the baseline SWMM model by ICON Engineering and the Phase
G interim conditions model.
VI. Variance Requests
No drainage variances are being requested at this time.
VII. Erosion Control
Montava Phase G has been preliminarily designed to be in compliance with the City of Fort Collins
Erosion Control Criteria and all Erosion Control Materials will be provided with the Final Drainage
Report. A separate Stormwater Management Plan has been provided with the PDR submittal in
support of the preliminary erosion control plans.
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VIII. Conclusion
A. Compliance
This preliminary drainage report has been prepared in accordance with the City of Fort Collins
Stormwater Criteria Manual for a Project Development Plan (PDP) submittal. The PDP plans
have also been prepared to be in compliance with city’s current drainage criteria.
B. Drainage Concept
In general, the proposed drainage approach is to focus on runoff reducing practices using the
Four Step Process developed by the Mile High Flood District. The single family lots will discharge
to the street section curb and getter, which will convey flows to strategically placed inlets to
meet depth and spread criteria and at low points, which will introduce flows to the proposed
storm sewer system. 75% of the newly developed areas will be connected to LID systems,
including Bioretention (Rain Gardens) and Linear Bioretention swales, which will treat frequently
occurring storm events prior to entering traditional water quality and detention ponds intended
to treat the remaining 25% of the site and attenuate downstream offsite discharge to the
maximum 2-year historic flow rates prior to entering the improved No. 8 Ditch piped segment,
which represent the historic receiving drainageway.
REFERENCES
1. Fort Collins Stormwater Criteria Manual, as adopted by the City Council of Fort Collins, as referenced
ins Section 26-500 of the Code of the City of Fort Collins, November 2017.
2. City of Fort Collins Cooper Slough Alternatives Analysis Update, prepared for City of Fort Collins
Department of Utilities, prepared by ICON Engineering, Inc., October 2017.
3. Impacts from the No. 8 and L&W Ditch Flows on the Selected Plan and Development Memorandum,
prepared for the City of Fort Collins, prepared by ICON Engineering, Inc., July 17, 2020.
4. Montava Planned Unit Development Master Drainage Study, by Martin/Martin, Inc., dated January
23, 2019
A-Supporting Documents
Soil Map—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/2/2021
Page 1 of 344954104495490449557044956504495730449581044958904495410449549044955704495650449573044958104495890496970497050497130497210497290497370497450497530497610497690
496970 497050 497130 497210 497290 497370 497450 497530 497610 497690
40° 36' 50'' N 105° 2' 9'' W40° 36' 50'' N105° 1' 37'' W40° 36' 33'' N
105° 2' 9'' W40° 36' 33'' N
105° 1' 37'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 150 300 600 900
Feet
0 50 100 200 300
Meters
Map Scale: 1:3,500 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 16, Sep 2, 2021
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 19, 2018—Aug
10, 2018
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Soil Map—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/2/2021
Page 2 of 3
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
22 Caruso clay loam, 0 to 1
percent slope
0.2 0.4%
35 Fort Collins loam, 0 to 3
percent slopes
0.0 0.0%
94 Satanta loam, 0 to 1 percent
slopes
5.5 9.9%
101 Stoneham loam, 1 to 3 percent
slopes
38.2 68.0%
102 Stoneham loam, 3 to 5 percent
slopes
10.9 19.5%
103 Stoneham loam, 5 to 9 percent
slopes
1.2 2.2%
Totals for Area of Interest 56.1 100.0%
Soil Map—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/2/2021
Page 3 of 3
Hydrologic Soil Group and Surface Runoff
This table gives estimates of various soil water features. The estimates are used
in land use planning that involves engineering considerations.
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 four hydrologic soil groups are:
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.
Surface runoff refers to the loss of water from an area by flow over the land
surface. Surface runoff classes are based on slope, climate, and vegetative
cover. The concept indicates relative runoff for very specific conditions. It is
assumed that the surface of the soil is bare and that the retention of surface
water resulting from irregularities in the ground surface is minimal. The classes
are negligible, very low, low, medium, high, and very high.
Report—Hydrologic Soil Group and Surface Runoff
Absence of an entry indicates that the data were not estimated. The dash
indicates no documented presence.
Hydrologic Soil Group and Surface Runoff–Larimer County Area, Colorado
Map symbol and soil name Pct. of map unit Surface Runoff Hydrologic Soil Group
22—Caruso clay loam, 0 to 1 percent slope
Caruso 85 High D
Hydrologic Soil Group and Surface Runoff---Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/2/2021
Page 1 of 2
Hydrologic Soil Group and Surface Runoff–Larimer County Area, Colorado
Map symbol and soil name Pct. of map unit Surface Runoff Hydrologic Soil Group
35—Fort Collins loam, 0 to 3 percent slopes
Fort collins 85 Low C
94—Satanta loam, 0 to 1 percent slopes
Satanta 90 Negligible C
101—Stoneham loam, 1 to 3 percent slopes
Stoneham 90 Low B
102—Stoneham loam, 3 to 5 percent slopes
Stoneham 85 Low C
103—Stoneham loam, 5 to 9 percent slopes
Stoneham 85 Medium B
Data Source Information
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 16, Sep 2, 2021
Hydrologic Soil Group and Surface Runoff---Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/2/2021
Page 2 of 2
National Flood Hazard Layer FIRMette
0 500 1,000 1,500 2,000250
Feet
Ü
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
SPECIAL FLOOD
HAZARD AREAS
Without Base Flood Elevation (BFE)
Zone A, V, A99
With BFE or DepthZone AE, AO, AH, VE, AR
Regulatory Floodway
0.2% Annual Chance Flood Hazard, Areas
of 1% annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mileZone X
Future Conditions 1% Annual
Chance Flood HazardZone X
Area with Reduced Flood Risk due to
Levee. See Notes.Zone X
Area with Flood Risk due to LeveeZone D
NO SCREEN Area of Minimal Flood Hazard Zone X
Area of Undetermined Flood HazardZone D
Channel, Culvert, or Storm Sewer
Levee, Dike, or Floodwall
Cross Sections with 1% Annual Chance
17.5 Water Surface Elevation
Coastal Transect
Coastal Transect Baseline
Profile Baseline
Hydrographic Feature
Base Flood Elevation Line (BFE)
Effective LOMRs
Limit of Study
Jurisdiction Boundary
Digital Data Available
No Digital Data Available
Unmapped
This map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.
The basemap shown complies with FEMA's basemap
accuracy standards
The flood hazard information is derived directly from the
authoritative NFHL web services provided by FEMA. This map
was exported on 12/13/2021 at 1:15 PM and does not
reflect changes or amendments subsequent to this date and
time. The NFHL and effective information may change or
become superseded by new data over time.
This map image is void if the one or more of the following map
elements do not appear: basemap imagery, flood zone labels,
legend, scale bar, map creation date, community identifiers,
FIRM panel number, and FIRM effective date. Map images for
unmapped and unmodernized areas cannot be used for
regulatory purposes.
Legend
OTHER AREAS OF
FLOOD HAZARD
OTHER AREAS
GENERAL
STRUCTURES
OTHER
FEATURES
MAP PANELS
8
B 20.2
The pin displayed on the map is an approximate
point selected by the user and does not represent
an authoritative property location.
1:6,000
105°2'13"W 40°36'56"N
105°1'35"W 40°36'29"N
Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020
ICONENGINEERING, INC.
Memorandum
7000 S. Yosemite Street, Suite 120, Centennial, CO 80112
p 303.221.0802 | f 303.221.4019
www.iconeng.com
TO: Dan Evans, P.E. City of Fort Collins
FROM: Craig Jacobson and Jaclyn Michaelsen, ICON Engineering, Inc.
DATE: July 17, 2020
RE: Impacts from the No. 8 and L&W Ditch flows on the Selected Plan
and Development
The purpose of this memo is to summarize the impact that increasing the flow in the No.8 Ditch
and Larimer and Weld Canal (LWC) has on the Upper Cooper development locations and the
Upper Cooper Slough Selected Plan.
Background
The Upper Cooper Slough Selected Plan was developed in 2017 by ICON Engineering, Inc.
(ICON). Prior to the 2017 report, an alternative analysis update on the Upper Cooper Slough
basin was also performed by ICON (Cooper Slough, Alternative Analysis Update, 2017). The
alternative analysis recommended drainage improvements and development criteria for the
Upper Cooper Slough Basin. The purpose of the 2017 Selected Plan report was to summarize
the recommendations in the alternative analysis study and to update the previous Selected Plan
for the basin (Anderson Consulting Engineers, 2006). The improvements recommended in the
2006 Selected Plan were modified in 2017 to reflect updates in hydrology and upcoming
development; however, the main goals for the improvements were not changed.
The 2017 Selected Plan improvement recommendations included:
1. North Poudre Reservoir No. 6 – Outlet Sill
2. Sod Farm Detention Pond and No. 8 Outlet Ditch Spill
3. Mountain Vista Diversion on No. 8 Outlet Ditch (to C&S Pond)
4. Removal of C&S RR Flow Split (C&S RR Railroad Diversion)
5. Crumb and C&S RR Regional Detention Pond
6. AB Detention Pond Improvements
7. Culvert Improvements at:
o Vine Drive Crossing
o Mulberry Street (SH-14)
o Mountain Vista Culvert – East flow path
o Mountain Vista Culvert – West flow path
8. Bank and Habitat Improvements
In addition to including the selected plan improvements, site specific development criteria for the
Mountain Vista and Anheuser Busch areas were recommended.
Since the creation of the selected plan there have been several potential developments
forthcoming in the Upper Cooper Slough Basin. These developments are in areas that have
potential impacts to the selected plan improvements. ICON was tasked with evaluating the
impacts that the developments would have on drainage and provide recommendations for
modifications, as necessary to the selected plan, as well as assisting the City in coordinating
recommendations with the different development groups.
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Effective Flows in the Canals and in Cooper Slough
The hydrologic model for the Upper Cooper Slough Basin was created using a combination of
EPA SWMM and HEC-RAS models. EPA SWMM was used to quantify flow through the basin as
runoff and concentrated discharge from the upstream boundary of the watershed to the LWC. At
the LWC, inflow hydrographs are extracted from the EPA SWMM model and added into an
unsteady flow HEC-RAS model representing the LWC through the Upper Cooper Slough and
Boxelder watersheds. The HEC-RAS model then determines changes in flow and water
elevations in the canal and hydrographs for where flow eventually overtops the canal banks and
proceeds downstream. These spill hydrographs from HEC-RAS are then added back into the
EPA SWMM model to quantify flows continuing further downstream through the basin.
The No. 8 Ditch runs south through the basin. It is modeled in EPA SWMM as a constant flow
hydrograph. The 2017 Selected Plan utilized a constant decreed flow of 125cfs for the No. 8
Ditch. Similarly, the selected plan used a constant decreed flow of 675cfs for the LWC in the
HEC-RAS model.
Following a meeting on March 11, 2020, the Larimer and Weld Irrigation Company (LWIC), who
represents both the No. 8 Ditch and LWC, have updated the decreed/maximum flows for both the
Larimer and Weld and the No. 8 Ditch to be considered with the selected plan updates. The LWIC
determined that the following two scenarios would need to be considered in planning and
collaboration with the ongoing development:
A) No. 8 Ditch maximum flow of 250cfs with a maximum flow of 675cfs in the LWC; and:
B) LWC conveying a decreed flow of 800cfs, with the No. 8 Ditch not contributing.
These changes in flow have shown to impact the improvements proposed in the 2017 Selected
Plan and subsequent development collaboration.
Impact that the increase in flow has on the Effective Conditions
The effective hydrologic model for the Cooper Slough Basin was most recently updated as part
of the Boxelder Creek, East Side Detention Facility (ESDF) LOMR. Similarly, to the selected plan
model, the ESDF model contains the combination of EPA SWMM and unsteady flow HEC-RAS
modeling, as well as the as-built data for the East Side Detention Facility and designed spill from
the LWC along Boxelder Creek. The ESDF modeling was used as the basis of revision for this
comparison. From the ESDF model, two additional separate models were created to evaluate
the changes from both canal scenarios shown above. Table 1 summarizes the impacts to the
flows in the Cooper Slough caused by the changes in irrigation flow conditions. As shown by the
table, the changes in flow conditions in the canals results in increases in 100-year flow along
Upper Cooper Slough for locations downstream. Scenario A, the increase in No. 8 Ditch flow to
250cfs has a more dramatic impact than Scenario B. This seems reasonable given Scenario A
increases net inflow to the modeling by 100cfs, compared to only the distribution increase in
Scenario B.
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Table 1: Additional flow impact to the Effective Model.
Node Description
A B
Difference
B - A
C
Difference
C - A Effective
Flow
Effective
with
250cfs in
No. 8
Ditch
Effective
with 0cfs
in No. 8
Ditch
(cfs) (cfs) (cfs) (cfs) (cfs)
909 Spill at LWC 740 797 57 751 11
866 East Vine Drive 777 834 57 788 11
413 Upstream RR 819 834 15 820 1
7417 Downstream RR 767 823 56 779 12
406 Upstream Mulberry 961 961 0 961 0
928 Split at Mulberry 708 755 47 722 14
Development in the area
There are four active upcoming developments within the Upper Cooper Slough basin.
1) Montava Development
The Montava Development is located around the C&S / Crumb Pond. This development is
expected to incorporate several of the 2017 planned stormwater improvements. The development
is proposing to formalize the C&S/Crumb and AB Ponds, formalize the Mountain Vista Diversion
on No. 8 Outlet Ditch (to Crumb Pond), and will address the C&S Railroad flow split upstream of
Richards Lake Road.
The conceptual design of the site has been prepared by Martin and Martin, Inc. The design
incorporates several onsite detention ponds with three large regional detention ponds (Pond A,
C&S/Crumb Pond and the AB Pond). The C&S/Crumb pond releases into the AB pond. Then
the AB Pond releases directly into the LWC along with an overflow flume that conveys higher
flows directly into Cooper Slough. This design has been incorporated into the hydrologic modeling
to analyze the changes that the design has on the basin. The impacts of the increase in ditch
flow is summarized in the following sections.
2) Water’s Edge Development
The Water’s Edge development is located adjacent to existing Sod Farm sump. This development
would incorporate the Sod Farm Detention Pond and formalize the No. 8 Ditch spill into and out
of the pond, as proposed by the selected plan.
No design has currently been provided for this location. Therefore, the changes from the No. 8
Ditch flow were based on analysis included in the original selected plan model. This analysis and
results are summarized in the following sections.
3) Country Club Reserve Development
The Country Club Reserve Development is located west of the Sod Farm, west of Turnberry Road
and south of East Douglas Road. Adjustments to the hydrologic model were made that
incorporates the overall intent of the development into the model. Specifically, Basin SB46 was
adjusted to discharge into a detention pond that matching the capacity of the existing 24” culvert
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(link 246). This development is located to the west of the No. 8 Ditch, therefore it is not impacted
by the increase in ditch flows.
4) Mountain Vista Dr and Timberline Road Mixed-Use Development
The Mountain Vista Drive and Timberline Road Mixed Use development is located downstream
near the LWC, south of Mountain Vista Drive. The No. 8 Ditch splits through the middle of the
development. The EPA SWMM model was adjusted to incorporate a future development at this
location. The following adjustments were made to the EPA SWMM model:
• Basin SB20 was subdivided into basins SB20, SB20_2 and SB20_3. SB20_2 and
SB20_3 represent existing development. SB20 represents a portion of the Mountain Vista
Drive and Timberline Road Mixed-Use Development.
• Inadvertent storage was added to basins SB20_2 and SB20_3. These basins also drain
directly to the LWC.
• Basin SB20 was joined with SB19.
• Basins SB18 and SB21 were joined and represent a portion of the Mountain Vista Drive
and Timberline Road Mixed-Use Development.
• Onsite detention was added to the Mountain Vista Drive and Timberline Road Mixed-Use
Development. The detention releases into the Larimer and Weld at the 2-year historic rate,
as defined by the exiting conditions EPA SWMM model.
The development is not impacted by the increase in ditch flows in the No. 8 or the LWC; however,
the potential changes in stormwater release has the potential to impact modeling and the
recommended improvements.
Initial Design of the Montava Development
The Montava Development incorporates the changes in land use for the development and both
the C&S / Crumb Pond and the AB Pond improvements defined in the 2017 Selected Plan. Slight
modifications were made to the selected plan recommendation to accommodate site development
needs and utility constraints. The current design has the C&S / Crumb Pond releasing into the
AB Pond with the AB Pond releasing flow through a low flow channel directly to the LWC and
overflow flume over the LWC into Cooper Slough.
Impact that the increase in flow has on the Montava Development
The initial design of the Montava Development was analyzed in EPA SWMM. The model was
adjusted to accounted for the two ditch scenarios. As seen in Table 2 below, the additional flow
in the ditches resulted in more flow in the Cooper Slough then previously accounted for. The
additional flow also adjusted the timing of the peaks of the hydrographs such that the current
design resulted in impacts downstream. As shown by the table, both new ditch scenarios,
combined with the development plan has a significant impact on flows downstream on Cooper
Slough. Unlike the change to the effective conditions, higher flows are now experienced in
Scenario B, with the increase in irrigation flow in the LWC.
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Table 2: Additional flow impact to Montava Development.
Node Description
A B
Difference
B - A
C
Difference
C - A Effective
Flow
Montava
(250cfs in
No.8)
Montava
(0cfs in
No.8)
(cfs) (cfs) (cfs) (cfs) (cfs)
909 Spill at LWC 740 787 47.4 855 115.8
866 East Vine Drive 777 834 57.3 902 125.0
413 Upstream RR 819 940 121.2 962 142.9
7417 Downstream RR 767 893 125.6 939 172.3
406 Upstream Mulberry 961 961 0.0 961 0.0
928 Split at Mulberry 708 760 52.5 807 99.7
Recommended Adjustments to Montava’s Design Plan
The Montava Development proposes a series of detention ponds as well as large drainage
channels. Due to the dynamic nature of the swales and detention facilities in the development,
the drainage facilities in the Montava Development were evaluated in SWMM using the dynamic
wave methodology. The dynamic wave methodology can account for channel storage, backwater,
entrance/exit losses, flow reversal and pressurized flow.
The two ditch scenarios were run using dynamic modeling. The same adjustments were made
to both model scenarios to ensure that the ponds functions effectively, regardless of the flow
assumptions in the ditches. With the dynamic modeling, the drainage facilities, as previously
proposed did not alleviate downstream impacts; however minor adjustments were noted to better
maximize the detention ponds and minimize the flow impacts into Cooper Slough. The proposed
adjustments to Montava’s current design are as follows:
1) Overflow connection between Crumb Pond (pond 426) and the AB Pond (pond 425): The
overflow culvert can be reduced from a 3’x15’ RCBC to a 3’x13.5’ RCBC.
2) Overflow flume from the AB Pond (pond 425) to Cooper Slough: The flume can be
changed to 70ft in width from 100ft in width.
3) Overflow connection between Crumb Pond (pond 426) and Overflow Pond (pond
426_Overflow): The overflow channel between the ponds needs to be increased to convey
more flow to the Overflow Pond.
These adjustments are recommendations. The Montava development team will need to ensure
that the design configuration chosen does not increase the flows downstream on Cooper Slough
for both scenarios A and B.
The flow out of the system is summarized by the following table. The table summarizes the flow
along Cooper Slough, compared back to the Effective model:
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Table 3: Summary of Impacts along Cooper Slough from the Montava Development
Node Description
Eff A Difference
A - Eff
B Difference
B - Eff Effective
Flow 250cfs in No 8 0cfs in No 8
(cfs) (cfs) (cfs) (cfs) (cfs)
Link 185
Flow Out of AB Pond into Cooper
Slough --- 299 --- 291 ---
— Spill into Cooper Slough --- 448 --- 439 ---
909 US end of Cooper Slough 740 594 -146 666 -73
866 East Vine Drive 777 632 -144 706 -71
413 Upstream RR 819 766 -53 708 -111
7417 Downstream RR 767 709 -58 705 -62
406 Upstream Mulberry 961 961 0 961 0
928 Split at Mulberry 708 611 -96 660 -47
• Scenario A = Montava Development (250cfs in the No. 8 Ditch and 675cfs in the L&W Canal).
• Scenario B = Montava Development (0cfs in the No. 8 Ditch and 800cfs in the L&W Canal).
Under this scenario, the flow into Cooper Slough is controlled by the spill from the AB Pond as
well as the spill out of the L&W Canal. When the No. 8 ditch is conveying 250cfs, there is a peak
flow of 299cfs from the AB pond and 448cfs from the L&W Canal, resulting in a peak flow in
Cooper Slough of 594cfs. When the No. 8 ditch is empty, there is a peak flow of 291cfs from the
AB pond and 439cfs from the L&W Canal, resulting in a peak flow in Cooper Slough of 666cfs.
The impacts are greater to the Montava Development when there is 250cfs in the No. 8 Ditch.
More flow spills through the development and ultimately to the proposed ponds when the No. 8
ditch is conveying the decreed flow. The impact of the additional flow can be seen in the Crumb
Pond and the Overflow Pond. There is approximately 30 ac-ft more volume required under this
scenario.
While the impacts to the development north of the L&W Canal appear to be controlled by the flow
in the No. 8, the impacts of the Cooper Slough south of the L&W Canal are controlled by the flow
assumptions in the L&W Canal. The L&W Canal spills approximately 100cfs more into Cooper
Slough with the addition of 125cfs in the L&W Canal.
The design of the Montava Development, as well as any development to the North of the L&W
Canal, should be designed for scenario A (250cfs in the No. 8 Ditch). The developments need
to ensure that the flows south of the L&W Canal are not exceed for both scenarios A and B. As
shown above, with these changes at Montava, these goals are achieved. These scenarios also
rely on it being acceptable to the City to incorporate a dynamic model for the site development
to identify flow changes along Cooper Slough downstream.
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Sod Farm Detention
With the change of the maximum flow in the No. 8 Ditch from 125cfs to 250cfs, more water will
spill into the Sod Farm Pond during both the existing and selected plan conditions. The volume
of water in the inadvertent pond at the Sod Farm in the updated effective conditions increases
from 112.5ac-ft to 138.4ac-ft with the revised ditch flow.
The Selected Plan of improvements formalizes the inadvertent detention at the Sod Farm while
diverting the storm flows from the irrigation canal to a proposed detention pond. The plan
proposes to formalize the spill into the Sod Farm from the No. 8 ditch, spilling everything in excess
of the decreed flow of 250cfs into the proposed Sod Farm Pond. The detained flows are returned
to the No. 8 through a proposed culvert.
The Sod Farm improvements were only evaluated with the scenario that has 250cfs in the No.8.
The more flow in the No. 8 during a storm event, the more flow that is being diverted to the Sod
Farm. The following summarizes the Sod Farm Detention Pond Selected Plan design and
impacts:
• Effective Inadvertent Detention
o Volume = 138.4 ac-ft
o Flow Out = 0cfs
o Flow in from the No. 8 Ditch through a unformalized spill = 617 cfs
• Selected Plan Detention Volume
o Volume = 164.1 ac-ft
o Flow Out through a proposed 36-in RCP = 55cfs
o Flow in from the No. 8 Ditch through a formalized spill = 735 cfs
Through dynamic modeling, the Sod Farm detention shows minimal impact to the proposed
Montava detention ponds (See Table 5). The flow ultimately leaving the AB pond and spilling into
Cooper Slough is reduced by approximately 10cfs. The spill out of the L&W Canal and into
Cooper Slough is not changed. However, the timing of the flows are adjusted slightly, reducing
the total flow at the upstream end of Cooper Slough by 25cfs. The table below summarizes the
impacts of the Sod Farm Detention Pond to the flow in Cooper Slough.
Table 4: Summary of Impacts along Cooper Slough from the Sod Farm Detention
Node Description
Eff A B C (w/ SF)
Diff
C- A
Diff
C- Eff
D (w/ SF)
Diff
D- B
Diff
D - Eff Effective 250cfs in
No 8
0cfs in
No 8
250cfs in
No 8
0cfs in
No 8
(cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs)
Link 185 Out of AB Pond into CS --- 299 291 281 -18 --- 276 -15 ---
Spill Peak Spill out of L&W --- 448 439 447 -1 --- 438 -1 ---
909 US Cooper Slough 740 594 666 569 -25 -171 651 -15 -89
866 East Vine Drive 777 632 706 706 74 -71 690 -16 -87
413 Upstream RR 819 766 708 708 -58 -111 692 -16 -127
7417 Downstream RR 767 709 705 705 -4 -62 690 -15 -77
406 Upstream Mulberry 961 961 961 961 0 0 961 0 0
928 Split at Mulberry 708 611 660 660 49 -48 652 -8 -56
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• Scenario A = Montava Development (250cfs in the No. 8 Ditch and 675cfs in the L&W Canal).
• Scenario B = Montava Development (0cfs in the No. 8 Ditch and 800cfs in the L&W Canal).
• Scenario C = Montava Development and the Sod Farm Detention (250cfs in the No. 8 Ditch and
675cfs in the L&W Canal).
• Scenario D = Montava Development and the Sod Farm Detention (0cfs in the No. 8 Ditch and
800cfs in the L&W Canal).
With the Selected Plan, the outflow from the Sod Farm Pond is a constant 55cfs to the No. 8
Ditch. Should the diversion be designed with a different release from the Sod Farm, this could
impact downstream facilities in Montava. The development team for Water’s Edge will need to
insure that the proposed pond release does not adversely impact downstream developments.
No. 6 Reservoir Sill Improvements
The Selected Plan proposed to modify the existing North Poudre Reservoir No. 6 spillway by
adding an 8-inch iron plate. This will effectively add 307 ac-ft of flood storage on top of the existing
reservoir. Peak outflow from the reservoir will also be reduced from 547cfs to 754cfs.
The improvements have a significant impact to the detention volume required in the Montava
Development. The following tables summarizes the required detention in the Montava
development, with and without the No. 6 improvements.
Table 5: Pond Volumes Summary
Detention Pond
A B C D E F
250cfs in
No 8
0cfs in
No 8
250cfs in
No 8
0cfs in
No 8
250cfs in
No 8
0cfs in
No 8
Ac-ft Ac-ft Ac-ft Ac-ft Ac-ft Ac-ft
Pond A 124.5 124.5 124.5 124.5 85.2 85.2
Crumb Pond 307.8 285.7 309.6 283.4 190.2 181.2
AB Pond 46.9 46.3 45.6 45.3 44.8 44.4
Crumb Pond Overflow 77.4 70.0 78.1 65.4 19.6 13.0
• Scenario A = Montava Development (250cfs in the No. 8 Ditch and 675cfs in the L&W Canal).
• Scenario B = Montava Development (0cfs in the No. 8 Ditch and 800cfs in the L&W Canal).
• Scenario C = Montava Development and the Sod Farm Detention (250cfs in the No. 8 Ditch and
675cfs in the L&W Canal).
• Scenario D = Montava Development and the Sod Farm Detention (0cfs in the No. 8 Ditch and
800cfs in the L&W Canal).
• Scenario E = Montava Development, Sod Farm Detention and No. 6 Improvements (250cfs in the
No. 8 Ditch and 675cfs in the L&W Canal).
• Scenario F = Montava Development, Sod Farm Detention and No. 6 Improvements (0cfs in the No.
8 Ditch and 800cfs in the L&W Canal).
The No. 6 Reservoir improvements have the potential to reduce the volume required in the
Montava Development by approximately 217 ac-ft, from a total volume of 557 ac-ft to 340 ac-ft.
ICONENGINEERING, INC. Page 9 of 9
C:\ICON\UCS\Upper Cooper Slough - Montava Review 2020_07_17.docx
The table below summarizes the impacts of the No. 6 Reservoir improvements to the flow in
Cooper Slough.
Table 6: Summary of Impacts along Cooper Slough from the No. 6 Reservoir Detention
Node Description
Eff C D E
(w/ No. 6) Diff
E- C
Diff
E- Eff
F
(w/ No.6) Diff
F- D
Diff
F - Eff Effective 250cfs in
No 8
0cfs in
No 8
250cfs in
No 8
0cfs in
No 8
(cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs)
Link 185 Out of AB Pond into CS --- 281 276 269 -12 --- 264 -12 ---
Spill Peak Spill out of L&W --- 447 438 447 0 --- 438 0 ---
909 US Cooper Slough 740 569 651 554 -15 -186 636 -15 -104
866 East Vine Drive 777 706 690 593 -113 -184 676 -14 -101
413 Upstream RR 819 708 692 766 58 -53 682 -10 -137
7417 Downstream RR 767 705 690 708 3 -59 675 -15 -92
406 Upstream Mulberry 961 961 961 961 0 0 961 0 0
928 Split at Mulberry 708 660 652 574 -86 -134 637 -15 -71
• Scenario C = Montava Development and the Sod Farm Detention (250cfs in the No. 8 Ditch and
675cfs in the L&W Canal).
• Scenario D = Montava Development and the Sod Farm Detention (0cfs in the No. 8 Ditch and
800cfs in the L&W Canal).
• Scenario E = Montava Development, Sod Farm Detention and No. 6 Improvements (250cfs in the
No. 8 Ditch and 675cfs in the L&W Canal).
• Scenario F = Montava Development, Sod Farm Detention and No. 6 Improvements (0cfs in the No.
8 Ditch and 800cfs in the L&W Canal).
Montava – Phase G PDP
December 14, 2021
B-Hydrologic Calculations
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.25 0.25 0.25 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
5.95 0.68 0.68 0.68 0.78 67.6%
AREA
(ACRES) C2 C5 C10 C100
0.05 0.25 0.25 0.25 0.31 2%
0.12 0.95 0.95 0.95 1.00 100%
0.16 0.75 0.75 0.75 0.81 72.3%
AREA
(ACRES) C2 C5 C10 C100
0.07 0.25 0.25 0.25 0.31 2%
0.07 0.95 0.95 0.95 1.00 100%
0.14 0.62 0.62 0.62 0.67 53.5%
AREA
(ACRES) C2 C5 C10 C100
0.06 0.25 0.25 0.25 0.31 2%
0.07 0.95 0.95 0.95 1.00 100%
0.14 0.62 0.62 0.62 0.67 53.5%
AREA
(ACRES) C2 C5 C10 C100
0.06 0.25 0.25 0.25 0.31 2%
0.23 0.95 0.95 0.95 1.00 100%
0.29 0.80 0.80 0.80 0.85 79.1%
AREA
(ACRES) C2 C5 C10 C100
0.09 0.25 0.25 0.25 0.31 2%
0.12 0.95 0.95 0.95 1.00 100%
0.22 0.65 0.65 0.65 0.71 58.1%
AREA
(ACRES) C2 C5 C10 C100
0.05 0.25 0.25 0.25 0.31 2%
0.24 0.95 0.95 0.95 1.00 100%
0.71 0.65 0.65 0.65 0.81 70%
1.00 0.70 0.70 0.70 0.83 73.8%
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
SUB-BASIN COMPOSITE
SUB-BASIN
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/13/21
JURISDICTIONAL STANDARD
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
LANDSCAPE
LANDSCAPE
SUB-BASIN COMPOSITE
2.1 ASPHALT/CONCRETE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.2
PERCENT
IMPERVIOUSNESS
2.3
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.4
LANDSCAPE
ASPHALT/CONCRETE
COMPOSITE RUNOFF COEFFICIENTS
PERCENT
IMPERVIOUSNESS
2.5
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
COMPOSITE RUNOFF COEFFICIENTSSURFACE CHARACTERISTICS
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.6
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
12/14/2021 1:51 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(1-16).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.25 0.25 0.25 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
5.95 0.68 0.68 0.68 0.78 67.6%
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/13/21
JURISDICTIONAL STANDARD
LANDSCAPE
AREA
(ACRES) C2 C5 C10 C100
0.02 0.25 0.25 0.25 0.31 2%
0.15 0.65 0.65 0.65 0.81 70%
0.16 0.95 0.95 0.95 1.00 100%
0.34 0.77 0.77 0.77 0.87 79.7%
AREA
(ACRES) C2 C5 C10 C100
0.06 0.25 0.25 0.25 0.31 2%
0.65 0.65 0.65 0.65 0.81 70%
0.26 0.95 0.95 0.95 1.00 100%
0.97 0.71 0.71 0.71 0.83 74.1%
AREA
(ACRES) C2 C5 C10 C100
0.08 0.25 0.25 0.25 0.31 2%
0.32 0.65 0.65 0.65 0.81 70%
0.39 0.95 0.95 0.95 1.00 100%
0.79 0.76 0.76 0.76 0.85 77.7%
AREA
(ACRES) C2 C5 C10 C100
0.49 0.25 0.25 0.25 0.31 2%
0.49 0.25 0.25 0.25 0.31 2.0%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.25 0.25 0.25 0.31 2%
0.08 0.95 0.95 0.95 1.00 100%
0.10 0.81 0.81 0.81 0.86 80.4%
LANDSCAPE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
PERCENT
IMPERVIOUSNESS
2.9
LANDSCAPE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.8
LANDSCAPE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
SUB-BASIN SURFACE CHARACTERISTICS
PERCENT
IMPERVIOUSNESS
2.7
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
PERCENT
IMPERVIOUSNESS
2.11
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.10
LANDSCAPE
COMPOSITE RUNOFF COEFFICIENTS
SUB-BASIN COMPOSITE
12/14/2021 1:52 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(1-16).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.25 0.25 0.25 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
5.95 0.68 0.68 0.68 0.78 67.6%
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/13/21
JURISDICTIONAL STANDARD
LANDSCAPE
AREA
(ACRES) C2 C5 C10 C100
0.02 0.25 0.25 0.25 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.11 0.82 0.82 0.82 0.87 82.2%
AREA
(ACRES) C2 C5 C10 C100
0.08 0.95 0.95 0.95 1.00 100%
0.30 0.65 0.65 0.65 0.81 70%
0.38 0.71 0.71 0.71 0.85 76.4%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.25 0.25 0.25 0.31 2%
0.32 0.65 0.65 0.65 0.81 70%
0.12 0.95 0.95 0.95 1.00 100%
0.06 0.08 0.18 0.28 0.52 5%
0.52 0.64 0.65 0.66 0.80 67.2%
AREA
(ACRES) C2 C5 C10 C100
0.15 0.65 0.65 0.65 0.81 70%
0.05 0.95 0.95 0.95 1.00 100%
0.20 0.73 0.73 0.73 0.86 77.5%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.25 0.25 0.25 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.11 0.82 0.82 0.82 0.87 82.2%
5.95 0.68 0.68 0.68 0.78 67.6%
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.15
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.13
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.12
LANDSCAPE
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
2.16
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
2.14
LANDSCAPE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
PARKS, CEMETERIES
SUB-BASIN COMPOSITE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
12/14/2021 1:52 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(1-16).xlsm
CALCULATED BY:JOB NO:
CHECKED BY:PROJECT:
DATE:
Is Project Urban? Yes
AREA LENGTH SLOPE ti LENGTH SLOPE VEL.tt COMP.TOT. LENGTH SLOPE IMP tc tc
ac ft ft/ft min ft ft/ft fps min tc ft ft/ft % First DP min
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)(16) (17)
2.1 0.75 0.16 19 0.0200 2.2 210 0.0060 20 1.55 2.3 4.5 229.0 0.01 72.3% 11.3 5.0
2.2 0.62 0.14 20 0.0200 3.1 178 0.0060 20 1.55 1.9 5.0 198.0 0.01 53.5% 11.1 5.0
2.3 0.62 0.14 22 0.0200 3.2 169 0.0080 20 1.79 1.6 4.8 191.0 0.01 53.5% 11.1 5.0
2.4 0.80 0.29 21 0.0200 2.0 391 0.0140 20 2.37 2.8 4.7 412.0 0.01 79.1% 12.3 5.0
2.5 0.65 0.22 21 0.0200 3.0 212 0.0140 20 2.37 1.5 4.5 233.0 0.01 58.1% 11.3 5.0
2.6 0.70 1.00 139 0.0100 8.5 295 0.0080 20 1.79 2.7 11.3 434.0 0.01 73.8% 12.4 11.3
2.7 0.77 0.34 41 0.0100 3.8 195 0.0070 20 1.67 1.9 5.8 236.0 0.01 79.7% 11.3 5.8
2.8 0.71 0.97 42 0.0130 4.2 412 0.0150 20 2.45 2.8 7.0 454.0 0.01 74.1% 12.5 7.0
2.9 0.76 0.79 23 0.0200 2.3 551 0.0120 20 2.19 4.2 6.5 574.0 0.01 77.7% 13.2 6.5
2.10 0.25 0.49 148 0.2500 6.5 96 0.0200 15 2.12 0.8 7.2 244.0 0.16 2.0% 11.4 7.2
2.11 0.81 0.10 24 0.0200 2.0 95 0.0110 20 2.10 0.8 2.8 119.0 0.01 80.4% 10.7 5.0
2.12 0.82 0.11 24 0.0200 2.0 95 0.0110 20 2.10 0.8 2.7 119.0 0.01 82.2% 10.7 5.0
2.13 0.71 0.38 145 0.0090 8.8 32 0.0050 20 1.41 0.4 9.2 177.0 0.01 76.4% 11.0 9.2
2.14 0.65 0.52 200 0.0050 14.4 105 0.0200 20 2.83 0.6 15.1 305.0 0.01 67.2% 11.7 11.7
2.15 0.73 0.20 60 0.0050 6.5 66 0.0060 20 1.55 0.7 7.2 126.0 0.01 77.5% 10.7 7.2
2.16 0.82 0.11 22 0.0200 1.9 162 0.0080 20 1.79 1.5 3.4 184.0 0.01 82.2% 11.0 5.0
*Velocity (V) = CvSw0.5
TABLE 6-2
*Table 6-2, UDFCD (V.1), Chapter 6, Page 6-5
in which: Cv = Conveyance Coefficient (See Table Above)
Sw = Watercourse Slope (ft/ft)
E.BEDNAR
R.BYRNE
12/13/21
INITIAL/OVERLAND
TIME OF CONCENTRATION SUMMARY
TRAVEL TIME
19.1354
MONTAVA PHASE 1A
STANDARD FORM SF-2
(RATIONAL METHOD PROCEDURE)
REMARKS
tc CHECK (URBANIZED BASINS)
Pond
Type of Land Surface Conveyance Coefficient, Cv
Nearly Bare Ground 10
Grassed Waterway 15
5
Short Pasture and Lawns 7
Paved Areas and Shallow Paved Swales 20
Heavy Meadow 2.5
Tillage / Field
BASIN
DESIGN
POINT C5 Cv
DATA
SUB-BASIN
TIME (ti)(tt)
TOC
12/14/2021 1:53 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(1-16).xlsm
CALCULATED BY:E.BEDNAR JOB NO:19.1354
CHECKED BY:R.BYRNE PROJECT:MONTAVA PHASE 1A
DATE:12/13/21 DESIGN STORM:2-YR
ONE-HR PRECIP:0
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
2.1 0.16 0.75 5.0 0.12 2.85 0.35
2.2 0.14 0.62 5.0 0.09 2.85 0.25
2.3 0.14 0.62 5.0 0.08 2.85 0.24
2.4 0.29 0.80 5.0 0.23 2.85 0.67
2.5 0.22 0.65 5.0 0.14 2.85 0.40
2.6 1.00 0.70 11.3 0.70 2.13 1.49
2.7 0.34 0.77 5.8 0.26 2.67 0.69
2.8 0.97 0.71 7.0 0.69 2.52 1.73
2.9 0.79 0.76 6.5 0.60 2.52 1.52
2.10 0.49 0.25 7.2 0.12 2.52 0.31
2.11 0.10 0.81 5.0 0.08 2.85 0.23
2.12 0.11 0.82 5.0 0.09 2.85 0.26
2.13 0.38 0.71 9.2 0.27 2.30 0.62
2.14 0.52 0.64 11.7 0.33 2.05 0.68
2.15 0.20 0.73 7.2 0.15 2.52 0.37
2.16 0.11 0.82 5.0 0.09 2.85 0.26
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
CxA
(AC)
I
(IN/HR)
Q
(CFS)
REMARKSAREA
(AC)
RUNOFF
COEFF
tc
(MIN)
BASIN DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF
tc
(MIN)
S(CxA)
(AC)
I
(IN/HR)
Q
(CFS)
2-YEAR
12/14/2021 1:53 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(1-16).xlsm
CALCULATED BY:E.BEDNAR JOB NO:19.1354
CHECKED BY:R.BYRNE PROJECT:MONTAVA PHASE 1A
DATE:12/13/21 DESIGN STORM:100-YR
ONE-HR PRECIP:0.00
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
2.1 0.16 0.81 5.0 0.13 9.95 1.31
2.2 0.14 0.67 5.0 0.09 9.95 0.93
2.3 0.14 0.67 5.0 0.09 9.95 0.90
2.4 0.29 0.85 5.0 0.25 9.95 2.47
2.5 0.22 0.71 5.0 0.15 9.95 1.53
2.6 1.00 0.83 11.3 0.83 7.42 6.16
2.7 0.34 0.87 5.8 0.29 9.31 2.74
2.8 0.97 0.83 7.0 0.80 8.80 7.06
2.9 0.79 0.85 6.5 0.67 8.80 5.92
2.10 0.49 0.31 7.2 0.15 8.80 1.34
2.11 0.10 0.86 5.0 0.09 9.95 0.86
2.12 0.11 0.87 5.0 0.10 9.95 0.95
2.13 0.38 0.85 9.2 0.32 8.03 2.60
2.14 0.52 0.80 11.7 0.42 7.16 2.99
2.15 0.20 0.86 7.2 0.17 8.80 1.51
2.16 0.11 0.87 5.0 0.10 9.95 0.95
BASIN DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF
tc
(MIN)
S(CxA)
(AC)
I
(IN/HR)
Q
(CFS)
REMARKSAREA
(AC)
RUNOFF
COEFF
tc
(MIN)
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
CxA
(AC)
I
(IN/HR)
Q
(CFS)
100-YEAR
12/14/2021 1:53 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(1-16).xlsm
PROJECT:
JOB NO:19.1354
DATE:12/13/21
DESIGN AREA %
Q2 Q100
POINT (ACRES) IMP.(CFS) (CFS)
2.1 0.16 72.3% 0.75 0.81 0.35 1.31
2.2 0.14 53.5% 0.62 0.67 0.25 0.93
2.3 0.14 53.5% 0.62 0.67 0.24 0.90
2.4 0.29 79.1% 0.80 0.85 0.67 2.47
2.5 0.22 58.1% 0.65 0.71 0.40 1.53
2.6 1.00 73.8% 0.70 0.83 1.49 6.16
2.7 0.34 79.7% 0.77 0.87 0.69 2.74
2.8 0.97 74.1% 0.71 0.83 1.73 7.06
2.9 0.79 77.7% 0.76 0.85 1.52 5.92
2.10 0.49 2.0% 0.25 0.31 0.31 1.34
2.11 0.10 80.4% 0.81 0.86 0.23 0.86
2.12 0.11 82.2% 0.82 0.87 0.26 0.95
2.13 0.38 76.4% 0.71 0.85 0.62 2.60
2.14 0.52 67.2% 0.64 0.80 0.68 2.99
2.15 0.20 77.5% 0.73 0.86 0.37 1.51
2.16 0.11 82.2% 0.82 0.87 0.26 0.95
5.95 67.6% 0.68 0.78 9.80 39.27
MONTAVA PHASE 1A
SITE COMPOSITE
BASIN
RUNOFF SUMMARY
C2 C100
RUNOFF_SUMMARY
12/14/2021 1:53 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(1-16).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
9.02 0.70 0.70 0.70 0.81 71.3%
AREA
(ACRES) C2 C5 C10 C100
0.05 0.95 0.95 0.95 1.00 100%
0.25 0.65 0.65 0.65 0.81 70%
0.30 0.70 0.70 0.70 0.84 75.0%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.20 0.20 0.20 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.26 0.65 0.65 0.65 0.81 70%
0.37 0.69 0.69 0.69 0.83 73.0%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.20 0.20 0.20 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.11 0.79 0.79 0.79 0.86 79.5%
AREA
(ACRES) C2 C5 C10 C100
0.05 0.95 0.95 0.95 1.00 100%
0.21 0.65 0.65 0.65 0.81 70%
0.26 0.71 0.71 0.71 0.85 75.8%
AREA
(ACRES) C2 C5 C10 C100
0.03 0.20 0.20 0.20 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.42 0.65 0.65 0.65 0.81 70%
0.54 0.68 0.68 0.68 0.82 71.9%
AREA
(ACRES) C2 C5 C10 C100
0.04 0.20 0.20 0.20 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.13 0.73 0.73 0.73 0.80 70.9%
COMPOSITE RUNOFF COEFFICIENTS
SUB-BASIN COMPOSITE
SURFACE CHARACTERISTICS PERCENT
IMPERVIOUSNESS
2.22
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
2.21
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
PERCENT
IMPERVIOUSNESS
2.19
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
COMPOSITE RUNOFF COEFFICIENTS
PERCENT
IMPERVIOUSNESS
2.20
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
PERCENT
IMPERVIOUSNESS
SUB-BASIN COMPOSITE
2.17 MEDIUM DENSITY RESIDENTIAL
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.18
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
ASPHALT/CONCRETE
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/14/21
JURISDICTIONAL STANDARD
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
SUB-BASIN COMPOSITE
SUB-BASIN
12/14/2021 1:55 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(17-33).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
9.02 0.70 0.70 0.70 0.81 71.3%
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/14/21
JURISDICTIONAL STANDARD
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
AREA
(ACRES) C2 C5 C10 C100
0.09 0.20 0.20 0.20 0.31 2%
0.23 0.95 0.95 0.95 1.00 100%
0.61 0.65 0.65 0.65 0.81 70%
0.93 0.68 0.68 0.68 0.81 70.6%
AREA
(ACRES) C2 C5 C10 C100
0.12 0.20 0.20 0.20 0.31 2%
0.11 0.95 0.95 0.95 1.00 100%
0.38 0.65 0.65 0.65 0.81 70%
0.61 0.62 0.62 0.62 0.75 62.0%
AREA
(ACRES) C2 C5 C10 C100
0.21 0.95 0.95 0.95 1.00 100%
0.21 0.95 0.95 0.95 1.00 100.0%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.20 0.20 0.20 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.12 0.65 0.65 0.65 0.81 70%
0.23 0.73 0.73 0.73 0.84 75.6%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.20 0.20 0.20 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.11 0.81 0.81 0.81 0.87 81.6%
AREA
(ACRES) C2 C5 C10 C100
0.04 0.20 0.20 0.20 0.31 2%
0.19 0.95 0.95 0.95 1.00 100%
0.23 0.65 0.65 0.65 0.81 70%
0.46 0.73 0.73 0.73 0.84 76.2%
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.27
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
PERCENT
IMPERVIOUSNESS
2.26
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.25
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
PERCENT
IMPERVIOUSNESS
2.24
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.23
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
2.28
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
12/14/2021 1:55 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(17-33).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
9.02 0.70 0.70 0.70 0.81 71.3%
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/14/21
JURISDICTIONAL STANDARD
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
AREA
(ACRES) C2 C5 C10 C100
0.70 0.65 0.65 0.65 0.81 70%
0.27 0.95 0.95 0.95 1.00 100%
0.10 0.20 0.20 0.20 0.31 2%
1.07 0.68 0.68 0.68 0.81 71.2%
AREA
(ACRES) C2 C5 C10 C100
0.41 0.20 0.20 0.20 0.31 2%
0.91 0.65 0.65 0.65 0.81 70%
0.14 0.95 0.95 0.95 1.00 100%
1.46 0.55 0.55 0.55 0.69 53.8%
AREA
(ACRES) C2 C5 C10 C100
0.03 0.95 0.95 0.95 1.00 100%
0.18 0.65 0.65 0.65 0.81 70%
0.21 0.69 0.69 0.69 0.84 74.4%
AREA
(ACRES) C2 C5 C10 C100
0.22 0.20 0.20 0.20 0.31 2%
0.99 0.95 0.95 0.95 1.00 100%
0.09 0.65 0.65 0.65 0.81 70%
1.30 0.80 0.80 0.80 0.87 81.3%
AREA
(ACRES) C2 C5 C10 C100
0.17 0.20 0.20 0.20 0.31 2%
0.56 0.95 0.95 0.95 1.00 100%
0.73 0.78 0.78 0.78 0.84 77.2%
9.02 0.70 0.70 0.70 0.81 71.3%
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
SUB-BASIN COMPOSITE
2.30
LANDSCAPE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.29
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
LANDSCAPE
2.33
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
TOTAL SITE COMPOSITE
PERCENT
IMPERVIOUSNESS
2.31 ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
2.32
LANDSCAPE
12/14/2021 1:56 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(17-33).xlsm
CALCULATED BY:JOB NO:
CHECKED BY:PROJECT:
DATE:
Is Project Urban? Yes
AREA LENGTH SLOPE ti LENGTH SLOPE VEL.tt COMP.TOT. LENGTH SLOPE IMP tc tc
ac ft ft/ft min ft ft/ft fps min tc ft ft/ft % First DP min
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)(16) (17)
2.17 0.70 0.30 11 0.0350 1.6 158 0.0060 20 1.55 1.7 3.3 169.0 0.01 75.0% 10.9 5.0
2.18 0.69 0.37 102 0.0300 5.2 134 0.0070 20 1.67 1.3 6.5 236.0 0.02 73.0% 11.3 6.5
2.19 0.79 0.11 16 0.0200 1.8 145 0.0070 20 1.67 1.4 3.2 161.0 0.01 79.5% 10.9 5.0
2.20 0.71 0.26 115 0.0100 7.6 102 0.0110 20 2.10 0.8 8.4 217.0 0.01 75.8% 11.2 8.4
2.21 0.68 0.54 200 0.0100 10.7 74 0.0200 20 2.83 0.4 11.2 274.0 0.01 71.9% 11.5 11.2
2.22 0.73 0.13 13 0.0200 1.9 207 0.0100 20 2.00 1.7 3.6 220.0 0.01 70.9% 11.2 5.0
2.23 0.68 0.93 200 0.0200 8.5 112 0.0230 20 3.03 0.6 9.1 312.0 0.02 70.6% 11.7 9.1
2.24 0.62 0.61 200 0.0150 10.7 63 0.0150 20 2.45 0.4 11.1 263.0 0.02 62.0% 11.5 11.1
2.25 0.95 0.21 31 0.0200 1.2 208 0.0120 20 2.19 1.6 2.8 239.0 0.01 100.0% 11.3 5.0
2.26 0.73 0.23 20 0.0200 2.4 135 0.0120 20 2.19 1.0 3.4 155.0 0.01 75.6% 10.9 5.0
2.27 0.81 0.11 20 0.0200 1.9 135 0.0120 20 2.19 1.0 2.9 155.0 0.01 81.6% 10.9 5.0
2.28 0.73 0.46 17 0.0200 2.2 305 0.0120 20 2.19 2.3 4.5 322.0 0.01 76.2% 11.8 5.0
2.29 0.68 1.07 11 0.0320 1.7 423 0.0050 20 1.41 5.0 6.7 434.0 0.01 71.2% 12.4 6.7
2.30 0.55 1.46 113 0.0130 9.7 547 0.0050 15 1.06 8.6 18.3 660.0 0.01 53.8% 13.7 13.7
2.31 0.69 0.21 145 0.0150 7.8 29 0.0130 20 2.28 0.2 8.0 174.0 0.01 74.4% 11.0 8.0
2.32 0.80 1.30 135 0.0200 5.0 736 0.0060 20 1.55 7.9 12.9 871.0 0.01 81.3% 14.8 12.9
2.33 0.78 0.73 25 0.0200 2.3 766 0.0060 20 1.55 8.2 10.5 791.0 0.01 77.2% 14.4 10.5
*Velocity (V) = CvSw0.5
TABLE 6-2
*Table 6-2, UDFCD (V.1), Chapter 6, Page 6-5
in which: Cv = Conveyance Coefficient (See Table Above)
Sw = Watercourse Slope (ft/ft)
BASIN
DESIGN
POINT C5 Cv
DATA
SUB-BASIN
TIME (ti)(tt)
Paved Areas and Shallow Paved Swales 20
Heavy Meadow 2.5
Tillage / Field
Nearly Bare Ground 10
Grassed Waterway 15
5
Short Pasture and Lawns 7
Type of Land Surface Conveyance Coefficient, Cv
19.1354
MONTAVA PHASE 1A
STANDARD FORM SF-2
(RATIONAL METHOD PROCEDURE)
REMARKS
tc CHECK (URBANIZED BASINS)
E.BEDNAR
R.BYRNE
12/14/21
INITIAL/OVERLAND
TIME OF CONCENTRATION SUMMARY
TRAVEL TIME
TOC
12/14/2021 1:56 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(17-33).xlsm
CALCULATED BY:E.BEDNAR JOB NO:19.1354
CHECKED BY:R.BYRNE PROJECT:MONTAVA PHASE 1A
DATE:12/14/21 DESIGN STORM:2-YR
ONE-HR PRECIP:0
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
2.17 0.30 0.70 5.0 0.21 2.85 0.60
2.18 0.37 0.69 6.5 0.26 2.52 0.65
2.19 0.11 0.79 5.0 0.09 2.85 0.25
2.20 0.26 0.71 8.4 0.18 2.40 0.44
2.21 0.54 0.68 11.2 0.36 2.13 0.77
2.22 0.13 0.73 5.0 0.09 2.85 0.26
2.23 0.93 0.68 9.1 0.63 2.30 1.45
2.24 0.61 0.62 11.1 0.38 2.13 0.81
2.25 0.21 0.95 5.0 0.19 2.85 0.56
2.26 0.23 0.73 5.0 0.17 2.85 0.48
2.27 0.11 0.81 5.0 0.09 2.85 0.25
2.28 0.46 0.73 5.0 0.34 2.85 0.96
2.29 1.07 0.68 6.7 0.73 2.52 1.83
2.30 1.46 0.55 13.7 0.80 1.92 1.54
2.31 0.21 0.69 8.0 0.14 2.40 0.34
2.32 1.30 0.80 12.9 1.04 1.98 2.06
2.33 0.73 0.78 10.5 0.57 2.21 1.26
REMARKSAREA
(AC)
RUNOFF
COEFF
tc
(MIN)
BASIN DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF
tc
(MIN)
S(CxA)
(AC)
I
(IN/HR)
Q
(CFS)
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
CxA
(AC)
I
(IN/HR)
Q
(CFS)
2-YEAR
12/14/2021 1:56 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(17-33).xlsm
CALCULATED BY:E.BEDNAR JOB NO:19.1354
CHECKED BY:R.BYRNE PROJECT:MONTAVA PHASE 1A
DATE:12/14/21 DESIGN STORM:100-YR
ONE-HR PRECIP:0.00
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
2.17 0.30 0.84 5.0 0.25 9.95 2.51
2.18 0.37 0.83 6.5 0.31 8.80 2.72
2.19 0.11 0.86 5.0 0.09 9.95 0.94
2.20 0.26 0.85 8.4 0.22 8.38 1.85
2.21 0.54 0.82 11.2 0.44 7.42 3.26
2.22 0.13 0.80 5.0 0.10 9.95 1.01
2.23 0.93 0.81 9.1 0.75 8.03 6.05
2.24 0.61 0.75 11.1 0.46 7.42 3.39
2.25 0.21 1.00 5.0 0.21 9.95 2.04
2.26 0.23 0.84 5.0 0.19 9.95 1.92
2.27 0.11 0.87 5.0 0.10 9.95 0.95
2.28 0.46 0.84 5.0 0.39 9.95 3.86
2.29 1.07 0.81 6.7 0.87 8.80 7.63
2.30 1.46 0.69 13.7 1.01 6.71 6.76
2.31 0.21 0.84 8.0 0.17 8.38 1.45
2.32 1.30 0.87 12.9 1.13 6.92 7.83
2.33 0.73 0.84 10.5 0.61 7.42 4.55
REMARKSAREA
(AC)
RUNOFF
COEFF
tc
(MIN)
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
CxA
(AC)
I
(IN/HR)
Q
(CFS)
BASIN DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF
tc
(MIN)
S(CxA)
(AC)
I
(IN/HR)
Q
(CFS)
100-YEAR
12/14/2021 1:56 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(17-33).xlsm
PROJECT:
JOB NO:19.1354
DATE:12/14/21
DESIGN AREA %
Q2 Q100
POINT (ACRES) IMP.(CFS) (CFS)
2.17 0.30 75.0% 0.70 0.84 0.60 2.51
2.18 0.37 73.0% 0.69 0.83 0.65 2.72
2.19 0.11 79.5% 0.79 0.86 0.25 0.94
2.20 0.26 75.8% 0.71 0.85 0.44 1.85
2.21 0.54 71.9% 0.68 0.82 0.77 3.26
2.22 0.13 70.9% 0.73 0.80 0.26 1.01
2.23 0.93 70.6% 0.68 0.81 1.45 6.05
2.24 0.61 62.0% 0.62 0.75 0.81 3.39
2.25 0.21 100.0% 0.95 1.00 0.56 2.04
2.26 0.23 75.6% 0.73 0.84 0.48 1.92
2.27 0.11 81.6% 0.81 0.87 0.25 0.95
2.28 0.46 76.2% 0.73 0.84 0.96 3.86
2.29 1.07 71.2% 0.68 0.81 1.83 7.63
2.30 1.46 53.8% 0.55 0.69 1.54 6.76
2.31 0.21 74.4% 0.69 0.84 0.34 1.45
2.32 1.30 81.3% 0.80 0.87 2.06 7.83
2.33 0.73 77.2% 0.78 0.84 1.26 4.55
9.02 71.3% 0.70 0.81 11.20 46.34
MONTAVA PHASE 1A
SITE COMPOSITE
BASIN
RUNOFF SUMMARY
C2 C100
RUNOFF_SUMMARY
12/14/2021 1:57 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 2(17-33).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
8.78 0.65 0.65 0.65 0.77 65.7%
AREA
(ACRES) C2 C5 C10 C100
0.10 0.20 0.20 0.20 0.31 2%
0.34 0.65 0.65 0.65 0.81 70%
0.38 0.95 0.95 0.95 1.00 100%
0.82 0.73 0.73 0.73 0.84 75.6%
AREA
(ACRES) C2 C5 C10 C100
0.04 0.95 0.95 0.95 1.00 100%
0.24 0.65 0.65 0.65 0.81 70%
0.28 0.69 0.69 0.69 0.84 74.3%
AREA
(ACRES) C2 C5 C10 C100
0.07 0.20 0.20 0.20 0.31 2%
0.32 0.95 0.95 0.95 1.00 100%
0.41 0.65 0.65 0.65 0.81 70%
0.80 0.73 0.73 0.73 0.84 76.1%
AREA
(ACRES) C2 C5 C10 C100
0.05 0.95 0.95 0.95 1.00 100%
0.34 0.65 0.65 0.65 0.81 70%
0.38 0.69 0.69 0.69 0.83 73.6%
AREA
(ACRES) C2 C5 C10 C100
0.10 0.20 0.20 0.20 0.31 2%
0.41 0.95 0.95 0.95 1.00 100%
0.86 0.65 0.65 0.65 0.81 70%
1.37 0.71 0.71 0.71 0.83 74.0%
AREA
(ACRES) C2 C5 C10 C100
0.07 0.20 0.20 0.20 0.31 2%
0.20 0.95 0.95 0.95 1.00 100%
0.16 0.65 0.65 0.65 0.81 70%
0.43 0.71 0.71 0.71 0.81 72.2%
COMPOSITE RUNOFF COEFFICIENTS
PERCENT
IMPERVIOUSNESS
3.5
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
COMPOSITE RUNOFF COEFFICIENTSSURFACE CHARACTERISTICS
SUB-BASIN COMPOSITE
PERCENT
IMPERVIOUSNESS
3.3
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.4
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
3.1 MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.2
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
LANDSCAPE
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/13/21
JURISDICTIONAL STANDARD
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
SUB-BASIN COMPOSITE
SUB-BASIN
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.6
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
12/14/2021 1:58 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(1-17).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
8.78 0.65 0.65 0.65 0.77 65.7%
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/13/21
JURISDICTIONAL STANDARD
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
AREA
(ACRES) C2 C5 C10 C100
0.05 0.20 0.20 0.20 0.31 2%
0.13 0.95 0.95 0.95 1.00 100%
0.18 0.75 0.75 0.75 0.82 74.4%
AREA
(ACRES) C2 C5 C10 C100
0.11 0.95 0.95 0.95 1.00 100%
0.33 0.65 0.65 0.65 0.81 70%
0.43 0.72 0.72 0.72 0.86 77.3%
AREA
(ACRES) C2 C5 C10 C100
0.06 0.20 0.20 0.20 0.31 2%
0.30 0.95 0.95 0.95 1.00 100%
0.57 0.65 0.65 0.65 0.81 70%
0.93 0.72 0.72 0.72 0.84 75.2%
AREA
(ACRES) C2 C5 C10 C100
0.03 0.20 0.20 0.20 0.31 2%
0.18 0.95 0.95 0.95 1.00 100%
0.21 0.84 0.84 0.84 0.90 86.0%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.95 0.95 0.95 1.00 100%
0.22 0.65 0.65 0.65 0.81 70%
0.24 0.68 0.68 0.68 0.83 73.0%
AREA
(ACRES) C2 C5 C10 C100
0.08 0.95 0.95 0.95 1.00 100%
0.05 0.65 0.65 0.65 0.81 70%
0.13 0.83 0.83 0.83 0.93 88.5%SUB-BASIN COMPOSITE
COMPOSITE RUNOFF COEFFICIENTS
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.12
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
PERCENT
IMPERVIOUSNESS
3.11
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.10
LANDSCAPE
ASPHALT/CONCRETE
PERCENT
IMPERVIOUSNESS
3.9
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.8
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
COMPOSITE RUNOFF COEFFICIENTS
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.7
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
12/14/2021 1:59 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(1-17).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
8.78 0.65 0.65 0.65 0.77 65.7%
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/13/21
JURISDICTIONAL STANDARD
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
AREA
(ACRES) C2 C5 C10 C100
0.06 0.20 0.20 0.20 0.31 2%
0.26 0.95 0.95 0.95 1.00 100%
0.64 0.65 0.65 0.65 0.81 70%
0.96 0.70 0.70 0.70 0.83 74.0%
AREA
(ACRES) C2 C5 C10 C100
0.05 0.20 0.20 0.20 0.31 2%
0.13 0.95 0.95 0.95 1.00 100%
0.18 0.75 0.75 0.75 0.81 73.6%
AREA
(ACRES) C2 C5 C10 C100
0.04 0.20 0.20 0.20 0.31 2%
0.12 0.95 0.95 0.95 1.00 100%
0.16 0.75 0.75 0.75 0.82 74.3%
AREA
(ACRES) C2 C5 C10 C100
1.13 0.20 0.20 0.20 0.31 2%
1.13 0.20 0.20 0.20 0.31 2.0%
AREA
(ACRES) C2 C5 C10 C100
0.05 0.20 0.20 0.20 0.31 2%
0.11 0.95 0.95 0.95 1.00 100%
0.16 0.73 0.73 0.73 0.80 71.5%
8.78 0.65 0.65 0.65 0.77 65.7%
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.13
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.15
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.16
LANDSCAPE
3.14
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
3.17
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
TOTAL SITE COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
12/14/2021 1:59 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(1-17).xlsm
CALCULATED BY:JOB NO:
CHECKED BY:PROJECT:
DATE:
Is Project Urban? Yes
AREA LENGTH SLOPE ti LENGTH SLOPE VEL.tt COMP.TOT. LENGTH SLOPE IMP tc tc
ac ft ft/ft min ft ft/ft fps min tc ft ft/ft % First DP min
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)(16) (17)
3.1 0.73 0.82 28 0.0200 2.8 385 0.0050 20 1.41 4.5 7.3 413.0 0.01 75.6% 12.3 7.3
3.2 0.69 0.28 170 0.0160 8.3 0 0.0160 20 2.53 0.0 8.3 170.0 0.02 74.3% 10.9 8.3
3.3 0.73 0.80 100 0.0350 4.4 372 0.0050 20 1.41 4.4 8.8 472.0 0.01 76.1% 12.6 8.8
3.4 0.69 0.38 121 0.0130 7.5 69 0.0060 20 1.55 0.7 8.2 190.0 0.01 73.6% 11.1 8.2
3.5 0.71 1.37 100 0.0130 6.5 415 0.0050 20 1.41 4.9 11.3 515.0 0.01 74.0% 12.9 11.3
3.6 0.71 0.43 15 0.0200 2.2 338 0.0100 20 2.00 2.8 5.0 353.0 0.01 72.2% 12.0 5.0
3.7 0.75 0.18 20 0.0200 2.2 215 0.0100 20 2.00 1.8 4.0 235.0 0.01 74.4% 11.3 5.0
3.8 0.72 0.43 105 0.0140 6.3 134 0.0120 20 2.19 1.0 7.3 239.0 0.01 77.3% 11.3 7.3
3.9 0.72 0.93 18 0.0200 2.3 434 0.0070 20 1.67 4.3 6.6 452.0 0.01 75.2% 12.5 6.6
3.10 0.84 0.21 35 0.0200 2.2 187 0.0060 20 1.55 2.0 4.2 222.0 0.01 86.0% 11.2 5.0
3.11 0.68 0.24 106 0.0000 0.0 29 0.0080 20 1.79 0.3 0.3 135.0 0.00 73.0% 10.8 5.0
3.12 0.83 0.13 30 0.0200 2.1 122 0.0050 20 1.41 1.4 3.6 152.0 0.01 88.5% 10.8 5.0
3.13 0.70 0.96 17 0.0200 2.4 441 0.0060 20 1.55 4.7 7.1 458.0 0.01 74.0% 12.5 7.1
3.14 0.75 0.18 30 0.0160 3.0 211 0.0060 20 1.55 2.3 5.2 241.0 0.01 73.6% 11.3 5.2
3.15 0.75 0.16 17 0.0200 2.1 213 0.0100 20 2.00 1.8 3.8 230.0 0.01 74.3% 11.3 5.0
3.16 0.20 1.13 97 0.2500 5.5 123 0.0200 15 2.12 1.0 6.5 220.0 0.12 2.0% 11.2 6.5
3.17 0.73 0.16 27 0.0150 3.0 202 0.0080 20 1.79 1.9 4.9 229.0 0.01 71.5% 11.3 5.0
,,
*Velocity (V) = CvSw0.5
TABLE 6-2
*Table 6-2, UDFCD (V.1), Chapter 6, Page 6-5
in which: Cv = Conveyance Coefficient (See Table Above)
Sw = Watercourse Slope (ft/ft)
BASIN
DESIGN
POINT C5 Cv
DATA
SUB-BASIN
TIME (ti)(tt)
Paved Areas and Shallow Paved Swales 20
Heavy Meadow 2.5
Tillage / Field
Nearly Bare Ground 10
Grassed Waterway 15
5
Short Pasture and Lawns 7
Type of Land Surface Conveyance Coefficient, Cv
Pond
19.1354
MONTAVA PHASE 1A
STANDARD FORM SF-2
(RATIONAL METHOD PROCEDURE)
REMARKS
tc CHECK (URBANIZED BASINS)
E.BEDNAR
R.BYRNE
12/13/21
INITIAL/OVERLAND
TIME OF CONCENTRATION SUMMARY
TRAVEL TIME
TOC
12/14/2021 2:01 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(1-17).xlsm
CALCULATED BY:E.BEDNAR JOB NO:19.1354
CHECKED BY:R.BYRNE PROJECT:MONTAVA PHASE 1A
DATE:12/13/21 DESIGN STORM:2-YR
ONE-HR PRECIP:0
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
3.1 0.82 0.73 7.3 0.60 2.52 1.51
3.2 0.28 0.69 8.3 0.19 2.40 0.46
3.3 0.80 0.73 8.8 0.58 2.30 1.34
3.4 0.38 0.69 8.2 0.26 2.40 0.63
3.5 1.37 0.71 11.3 0.97 2.13 2.07
3.6 0.43 0.71 5.0 0.31 2.85 0.87
3.7 0.18 0.75 5.0 0.13 2.85 0.38
3.8 0.43 0.72 7.3 0.31 2.52 0.78
3.9 0.93 0.72 6.6 0.67 2.52 1.69
3.10 0.21 0.84 5.0 0.18 2.85 0.50
3.11 0.24 0.68 5.0 0.17 2.85 0.47
3.12 0.13 0.83 5.0 0.11 2.85 0.31
3.13 0.96 0.70 7.1 0.67 2.52 1.69
3.14 0.18 0.75 5.2 0.13 2.85 0.38
3.15 0.16 0.75 5.0 0.12 2.85 0.34
3.16 1.13 0.20 6.5 0.23 2.52 0.57
3.17 0.16 0.73 5.0 0.11 2.85 0.32
REMARKSAREA
(AC)
RUNOFF
COEFF
tc
(MIN)
BASIN DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF
tc
(MIN)
S(CxA)
(AC)
I
(IN/HR)
Q
(CFS)
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
CxA
(AC)
I
(IN/HR)
Q
(CFS)
2-YEAR
12/14/2021 2:01 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(1-17).xlsm
CALCULATED BY:E.BEDNAR JOB NO:19.1354
CHECKED BY:R.BYRNE PROJECT:MONTAVA PHASE 1A
DATE:12/13/21 DESIGN STORM:100-YR
ONE-HR PRECIP:0.00
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
3.1 0.82 0.84 7.3 0.69 8.80 6.06
3.2 0.28 0.84 8.3 0.24 8.38 1.97
3.3 0.80 0.84 8.8 0.67 8.03 5.40
3.4 0.38 0.83 8.2 0.32 8.38 2.64
3.5 1.37 0.83 11.3 1.14 7.42 8.44
3.6 0.43 0.81 5.0 0.35 9.95 3.47
3.7 0.18 0.82 5.0 0.14 9.95 1.44
3.8 0.43 0.86 7.3 0.37 8.80 3.25
3.9 0.93 0.84 6.6 0.78 8.80 6.88
3.10 0.21 0.90 5.0 0.19 9.95 1.88
3.11 0.24 0.83 5.0 0.20 9.95 2.02
3.12 0.13 0.93 5.0 0.12 9.95 1.20
3.13 0.96 0.83 7.1 0.80 8.80 7.00
3.14 0.18 0.81 5.2 0.14 9.95 1.43
3.15 0.16 0.82 5.0 0.13 9.95 1.31
3.16 1.13 0.31 6.5 0.35 8.80 3.08
3.17 0.16 0.80 5.0 0.12 9.95 1.23
REMARKSAREA
(AC)
RUNOFF
COEFF
tc
(MIN)
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
CxA
(AC)
I
(IN/HR)
Q
(CFS)
BASIN DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF
tc
(MIN)
S(CxA)
(AC)
I
(IN/HR)
Q
(CFS)
100-YEAR
12/14/2021 2:01 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(1-17).xlsm
PROJECT:
JOB NO:19.1354
DATE:12/13/21
DESIGN AREA %
Q2 Q100
POINT (ACRES) IMP.(CFS) (CFS)
3.1 0.82 75.6% 0.73 0.84 1.51 6.06
3.2 0.28 74.3% 0.69 0.84 0.46 1.97
3.3 0.80 76.1% 0.73 0.84 1.34 5.40
3.4 0.38 73.6% 0.69 0.83 0.63 2.64
3.5 1.37 74.0% 0.71 0.83 2.07 8.44
3.6 0.43 72.2% 0.71 0.81 0.87 3.47
3.7 0.18 74.4% 0.75 0.82 0.38 1.44
3.8 0.43 77.3% 0.72 0.86 0.78 3.25
3.9 0.93 75.2% 0.72 0.84 1.69 6.88
3.10 0.21 86.0% 0.84 0.90 0.50 1.88
3.11 0.24 73.0% 0.68 0.83 0.47 2.02
3.12 0.13 88.5% 0.83 0.93 0.31 1.20
3.13 0.96 74.0% 0.70 0.83 1.69 7.00
3.14 0.18 73.6% 0.75 0.81 0.38 1.43
3.15 0.16 74.3% 0.75 0.82 0.34 1.31
3.16 1.13 2.0% 0.20 0.31 0.57 3.08
3.17 0.16 71.5% 0.73 0.80 0.32 1.23
8.78 65.7% 0.65 0.77 13.43 54.38
MONTAVA PHASE 1A
SITE COMPOSITE
BASIN
RUNOFF SUMMARY
C2 C100
RUNOFF_SUMMARY
12/14/2021 2:01 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(1-17).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
5.70 0.68 0.68 0.68 0.81 70.5%
AREA
(ACRES) C2 C5 C10 C100
0.03 0.20 0.20 0.20 0.31 2%
0.18 0.95 0.95 0.95 1.00 100%
0.21 0.83 0.83 0.83 0.89 84.3%
AREA
(ACRES) C2 C5 C10 C100
0.05 0.95 0.95 0.95 1.00 100%
0.21 0.65 0.65 0.65 0.81 70%
0.26 0.71 0.71 0.71 0.85 76.0%
AREA
(ACRES) C2 C5 C10 C100
0.09 0.20 0.20 0.20 0.31 2%
0.59 0.65 0.65 0.65 0.81 70%
0.68 0.59 0.59 0.59 0.75 60.9%
AREA
(ACRES) C2 C5 C10 C100
0.11 0.20 0.20 0.20 0.31 2%
0.48 0.65 0.65 0.65 0.81 70%
0.59 0.57 0.57 0.57 0.72 57.7%
AREA
(ACRES) C2 C5 C10 C100
0.11 0.20 0.20 0.20 0.31 2%
0.41 0.65 0.65 0.65 0.81 70%
0.52 0.56 0.56 0.56 0.71 56.1%
AREA
(ACRES) C2 C5 C10 C100
0.05 0.95 0.95 0.95 1.00 100%
0.07 0.65 0.65 0.65 0.81 70%
0.12 0.78 0.78 0.78 0.89 82.8%
COMPOSITE RUNOFF COEFFICIENTS
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
PERCENT
IMPERVIOUSNESS
3.23
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.22
LANDSCAPE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
PERCENT
IMPERVIOUSNESS
3.19
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
3.21
LANDSCAPE
MEDIUM DENSITY RESIDENTIAL
COMPOSITE RUNOFF COEFFICIENTS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.20
LANDSCAPE
MEDIUM DENSITY RESIDENTIAL
PERCENT
IMPERVIOUSNESS
COMPOSITE RUNOFF COEFFICIENTSSURFACE CHARACTERISTICS
SUB-BASIN COMPOSITE
3.18 ASPHALT/CONCRETE
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
LANDSCAPE
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRIANAGE
12/13/21
JURISDICTIONAL STANDARD
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
SUB-BASIN SURFACE CHARACTERISTICS
SUB-BASIN COMPOSITE
SUB-BASIN
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
12/14/2021 2:02 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(18-35).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
5.70 0.68 0.68 0.68 0.81 70.5%
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRIANAGE
12/13/21
JURISDICTIONAL STANDARD
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
AREA
(ACRES) C2 C5 C10 C100
0.03 0.20 0.20 0.20 0.31 2%
0.15 0.95 0.95 0.95 1.00 100%
0.29 0.65 0.65 0.65 0.81 70%
0.47 0.72 0.72 0.72 0.84 75.2%
AREA
(ACRES) C2 C5 C10 C100
0.03 0.20 0.20 0.20 0.31 2%
0.16 0.95 0.95 0.95 1.00 100%
0.05 0.65 0.65 0.65 0.81 70%
0.24 0.79 0.79 0.79 0.87 81.2%
AREA
(ACRES) C2 C5 C10 C100
0.10 0.95 0.95 0.95 1.00 100%
0.37 0.65 0.65 0.65 0.81 70%
0.47 0.71 0.71 0.71 0.85 76.4%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.20 0.20 0.20 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.09 0.65 0.65 0.65 0.81 70%
0.21 0.74 0.74 0.74 0.84 76.4%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.20 0.20 0.20 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.12 0.80 0.80 0.80 0.86 80.5%
AREA
(ACRES) C2 C5 C10 C100
0.10 0.95 0.95 0.95 1.00 100%
0.29 0.65 0.65 0.65 0.81 70%
0.39 0.73 0.73 0.73 0.86 77.7%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.20 0.20 0.20 0.31 2%
0.10 0.95 0.95 0.95 1.00 100%
0.29 0.65 0.65 0.65 0.81 70%
0.41 0.70 0.70 0.70 0.83 74.0%
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.29
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.28
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
PERCENT
IMPERVIOUSNESS
3.27
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.26
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
PERCENT
IMPERVIOUSNESS
3.25
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.24
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
3.30
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
12/14/2021 2:03 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(18-35).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
5.70 0.68 0.68 0.68 0.81 70.5%
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRIANAGE
12/13/21
JURISDICTIONAL STANDARD
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
AREA
(ACRES) C2 C5 C10 C100
0.02 0.20 0.20 0.20 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.12 0.80 0.80 0.80 0.86 80.4%
AREA
(ACRES) C2 C5 C10 C100
0.06 0.20 0.20 0.20 0.31 2%
0.49 0.65 0.65 0.65 0.81 70%
0.55 0.60 0.60 0.60 0.76 62.6%
AREA
(ACRES) C2 C5 C10 C100
0.10 0.95 0.95 0.95 1.00 100%
0.07 0.65 0.65 0.65 0.81 70%
0.17 0.83 0.83 0.83 0.92 87.6%
AREA
(ACRES) C2 C5 C10 C100
0.01 0.20 0.20 0.20 0.31 2%
0.08 0.95 0.95 0.95 1.00 100%
0.09 0.84 0.84 0.84 0.90 85.2%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.20 0.20 0.20 0.31 2%
0.07 0.95 0.95 0.95 1.00 100%
0.09 0.77 0.77 0.77 0.84 76.6%
5.70 0.68 0.68 0.68 0.81 70.5%
PERCENT
IMPERVIOUSNESS
3.35
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
TOTAL SITE COMPOSITE
3.34
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.31
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.32
LANDSCAPE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
SUB-BASIN COMPOSITE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
3.33
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
12/14/2021 2:03 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(18-35).xlsm
CALCULATED BY:JOB NO:
CHECKED BY:PROJECT:
DATE:
Is Project Urban? Yes
AREA LENGTH SLOPE ti LENGTH SLOPE VEL.tt COMP.TOT. LENGTH SLOPE IMP tc tc
ac ft ft/ft min ft ft/ft fps min tc ft ft/ft % First DP min
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)(16) (17)
3.18 0.83 0.21 26 0.0150 2.2 298 0.0080 20 1.79 2.8 5.0 324.0 0.01 84.3% 11.8 5.0
3.19 0.71 0.26 68 0.0090 6.0 90 0.0050 20 1.41 1.1 7.1 158.0 0.01 76.0% 10.9 7.1
3.20 0.59 0.68 112 0.0230 7.4 106 0.0050 15 1.06 1.7 9.1 218.0 0.01 60.9% 11.2 9.1
3.21 0.57 0.59 101 0.0100 9.6 291 0.0050 15 1.06 4.6 14.2 392.0 0.01 57.7% 12.2 12.2
3.22 0.56 0.52 123 0.0100 10.8 134 0.0050 15 1.06 2.1 12.9 257.0 0.01 56.1% 11.4 11.4
3.23 0.78 0.12 39 0.0200 2.9 81 0.0050 20 1.41 1.0 3.8 120.0 0.01 82.8% 10.7 5.0
3.24 0.72 0.47 15 0.0200 2.1 331 0.0060 20 1.55 3.6 5.7 346.0 0.01 75.2% 11.9 5.7
3.25 0.79 0.24 15 0.0200 1.7 291 0.0060 20 1.55 3.1 4.9 306.0 0.01 81.2% 11.7 5.0
3.26 0.71 0.47 105 0.0100 7.2 156 0.0060 20 1.55 1.7 8.9 261.0 0.01 76.4% 11.5 8.9
3.27 0.74 0.21 95 0.0170 5.3 92 0.0140 20 2.37 0.6 6.0 187.0 0.02 76.4% 11.0 6.0
3.28 0.80 0.12 22 0.0200 2.0 143 0.0140 20 2.37 1.0 3.0 165.0 0.01 80.5% 10.9 5.0
3.29 0.73 0.39 200 0.0180 7.8 26 0.0180 20 2.68 0.2 7.9 226.0 0.02 77.7% 11.3 7.9
3.30 0.70 0.41 171 0.0180 7.8 106 0.0110 20 2.10 0.8 8.6 277.0 0.02 74.0% 11.5 8.6
3.31 0.80 0.12 25 0.0200 2.2 164 0.0110 20 2.10 1.3 3.5 189.0 0.01 80.4% 11.1 5.0
3.32 0.60 0.55 100 0.0150 7.9 74 0.0050 15 1.06 1.2 9.1 174.0 0.01 62.6% 11.0 9.1
3.33 0.83 0.17 17 0.0020 3.4 178 0.0080 20 1.79 1.7 5.1 195.0 0.01 87.6% 11.1 5.1
3.34 0.84 0.09 20 0.0200 1.7 122 0.0050 20 1.41 1.4 3.1 142.0 0.01 85.2% 10.8 5.0
3.35 0.77 0.09 20 0.0200 2.1 122 0.0050 20 1.41 1.4 3.6 142.0 0.01 76.6% 10.8 5.0
*Velocity (V) = CvSw0.5
TABLE 6-2
*Table 6-2, UDFCD (V.1), Chapter 6, Page 6-5
in which: Cv = Conveyance Coefficient (See Table Above)
Sw = Watercourse Slope (ft/ft)
BASIN
DESIGN
POINT C5 Cv
LID
LID
LID
DATA
SUB-BASIN
TIME (ti)(tt)
Paved Areas and Shallow Paved Swales 20
Heavy Meadow 2.5
Tillage / Field
Nearly Bare Ground 10
Grassed Waterway 15
5
Short Pasture and Lawns 7
Type of Land Surface Conveyance Coefficient, Cv
LID
19.1354
MONTAVA PHASE 1A
STANDARD FORM SF-2
(RATIONAL METHOD PROCEDURE)
REMARKS
tc CHECK (URBANIZED BASINS)
E.BEDNAR
R.BYRNE
12/13/21
INITIAL/OVERLAND
TIME OF CONCENTRATION SUMMARY
TRAVEL TIME
TOC
12/14/2021 2:03 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(18-35).xlsm
CALCULATED BY:E.BEDNAR JOB NO:19.1354
CHECKED BY:R.BYRNE PROJECT:MONTAVA PHASE 1A
DATE:12/13/21 DESIGN STORM:2-YR
ONE-HR PRECIP:0
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
3.18 0.21 0.83 5.0 0.17 2.85 0.50
3.19 0.26 0.71 7.1 0.19 2.52 0.47
3.20 0.68 0.59 9.1 0.40 2.30 0.92
3.21 0.59 0.57 12.2 0.33 2.05 0.68
3.22 0.52 0.56 11.4 0.29 2.13 0.62
3.23 0.12 0.78 5.0 0.10 2.85 0.27
3.24 0.47 0.72 5.7 0.34 2.67 0.90
3.25 0.24 0.79 5.0 0.19 2.85 0.54
3.26 0.47 0.71 8.9 0.33 2.30 0.77
3.27 0.21 0.74 6.0 0.15 2.67 0.41
3.28 0.12 0.80 5.0 0.09 2.85 0.26
3.29 0.39 0.73 7.9 0.28 2.40 0.68
3.30 0.41 0.70 8.6 0.29 2.30 0.66
3.31 0.12 0.80 5.0 0.09 2.85 0.26
3.32 0.55 0.60 9.1 0.33 2.30 0.76
3.33 0.17 0.83 5.1 0.14 2.85 0.40
3.34 0.09 0.84 5.0 0.08 2.85 0.22
3.35 0.09 0.77 5.0 0.07 2.85 0.19
REMARKSAREA
(AC)
RUNOFF
COEFF
tc
(MIN)
BASIN DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF
tc
(MIN)
S(CxA)
(AC)
I
(IN/HR)
Q
(CFS)
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
CxA
(AC)
I
(IN/HR)
Q
(CFS)
2-YEAR
12/14/2021 2:03 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(18-35).xlsm
CALCULATED BY:E.BEDNAR JOB NO:19.1354
CHECKED BY:R.BYRNE PROJECT:MONTAVA PHASE 1A
DATE:12/13/21 DESIGN STORM:100-YR
ONE-HR PRECIP:0.00
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
3.18 0.21 0.89 5.0 0.19 9.95 1.86
3.19 0.26 0.85 7.1 0.22 8.80 1.96
3.20 0.68 0.75 9.1 0.51 8.03 4.10
3.21 0.59 0.72 12.2 0.42 7.16 3.02
3.22 0.52 0.71 11.4 0.37 7.42 2.74
3.23 0.12 0.89 5.0 0.11 9.95 1.08
3.24 0.47 0.84 5.7 0.39 9.31 3.68
3.25 0.24 0.87 5.0 0.21 9.95 2.09
3.26 0.47 0.85 8.9 0.40 8.03 3.21
3.27 0.21 0.84 6.0 0.17 9.31 1.61
3.28 0.12 0.86 5.0 0.10 9.95 0.99
3.29 0.39 0.86 7.9 0.34 8.38 2.81
3.30 0.41 0.83 8.6 0.34 8.03 2.73
3.31 0.12 0.86 5.0 0.10 9.95 0.98
3.32 0.55 0.76 9.1 0.42 8.03 3.36
3.33 0.17 0.92 5.1 0.16 9.95 1.56
3.34 0.09 0.90 5.0 0.08 9.95 0.83
3.35 0.09 0.84 5.0 0.07 9.95 0.74
BASIN DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF
tc
(MIN)
S(CxA)
(AC)
I
(IN/HR)
Q
(CFS)
REMARKSAREA
(AC)
RUNOFF
COEFF
tc
(MIN)
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
CxA
(AC)
I
(IN/HR)
Q
(CFS)
100-YEAR
12/14/2021 3:03 PM
\\mmcivil.martin.local\civil\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(18-35).xlsm
PROJECT:
JOB NO:19.1354
DATE:12/13/21
DESIGN AREA %
Q2 Q100
POINT (ACRES) IMP.(CFS) (CFS)
3.18 0.21 84.3% 0.83 0.89 0.50 1.86
3.19 0.26 76.0% 0.71 0.85 0.47 1.96
3.20 0.68 60.9% 0.59 0.75 0.92 4.10
3.21 0.59 57.7% 0.57 0.72 0.68 3.02
3.22 0.52 56.1% 0.56 0.71 0.62 2.74
3.23 0.12 82.8% 0.78 0.89 0.27 1.08
3.24 0.47 75.2% 0.72 0.84 0.90 3.68
3.25 0.24 81.2% 0.79 0.87 0.54 2.09
3.26 0.47 76.4% 0.71 0.85 0.77 3.21
3.27 0.21 76.4% 0.74 0.84 0.41 1.61
3.28 0.12 80.5% 0.80 0.86 0.26 0.99
3.29 0.39 77.7% 0.73 0.86 0.68 2.81
3.30 0.41 74.0% 0.70 0.83 0.66 2.73
3.31 0.12 80.4% 0.80 0.86 0.26 0.98
3.32 0.55 62.6% 0.60 0.76 0.76 3.36
3.33 0.17 87.6% 0.83 0.92 0.40 1.56
3.34 0.09 85.2% 0.84 0.90 0.22 0.83
3.35 0.09 76.6% 0.77 0.84 0.19 0.74
5.70 70.5% 0.68 0.81 9.53 39.34
MONTAVA PHASE 1A
SITE COMPOSITE
BASIN
RUNOFF SUMMARY
C2 C100
RUNOFF_SUMMARY
12/14/2021 3:04 PM
\\mmcivil.martin.local\civil\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 3(18-
35).xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
10.31 0.62 0.62 0.62 0.73 60.4%
AREA
(ACRES) C2 C5 C10 C100
0.81 0.20 0.20 0.20 0.31 2%
0.81 0.20 0.20 0.20 0.31 2.0%
AREA
(ACRES) C2 C5 C10 C100
0.03 0.20 0.20 0.20 0.31 2%
0.19 0.95 0.95 0.95 1.00 100%
0.22 0.85 0.85 0.85 0.91 86.6%
AREA
(ACRES) C2 C5 C10 C100
0.01 0.20 0.20 0.20 0.31 2%
0.09 0.95 0.95 0.95 1.00 100%
0.10 0.88 0.88 0.88 0.93 90.2%
AREA
(ACRES) C2 C5 C10 C100
0.94 0.20 0.20 0.20 0.31 2%
0.94 0.20 0.20 0.20 0.31 2.0%
AREA
(ACRES) C2 C5 C10 C100
0.08 0.20 0.20 0.20 0.31 2%
0.52 0.95 0.95 0.95 1.00 100%
0.43 0.65 0.65 0.65 0.81 70%
1.02 0.77 0.77 0.77 0.87 80.1%
AREA
(ACRES) C2 C5 C10 C100
0.02 0.20 0.20 0.20 0.31 2%
0.10 0.95 0.95 0.95 1.00 100%
0.12 0.83 0.83 0.83 0.89 83.7%
COMPOSITE RUNOFF COEFFICIENTS
PERCENT
IMPERVIOUSNESS
4.5
LANDSCAPE
ASPHALT/CONCRETE
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN COMPOSITE
COMPOSITE RUNOFF COEFFICIENTS
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
4.6
LANDSCAPE
ASPHALT/CONCRETE
PERCENT
IMPERVIOUSNESS
4.3
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
4.4
LANDSCAPE
SUB-BASIN COMPOSITE
4.1
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
4.2
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
LANDSCAPE
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/13/21
JURISDICTIONAL STANDARD
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
12/14/2021 2:05 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 4.xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
10.31 0.62 0.62 0.62 0.73 60.4%
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/13/21
JURISDICTIONAL STANDARD
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
AREA
(ACRES) C2 C5 C10 C100
2.97 0.65 0.65 0.65 0.81 70%
2.97 0.65 0.65 0.65 0.81 70.0%
AREA
(ACRES) C2 C5 C10 C100
0.06 0.20 0.20 0.20 0.31 2%
0.32 0.95 0.95 0.95 1.00 100%
0.38 0.83 0.83 0.83 0.89 84.5%
AREA
(ACRES) C2 C5 C10 C100
0.05 0.20 0.20 0.20 0.31 2%
0.34 0.95 0.95 0.95 1.00 100%
0.39 0.85 0.85 0.85 0.91 87.4%
AREA
(ACRES) C2 C5 C10 C100
0.59 0.20 0.20 0.20 0.31 2%
0.59 0.20 0.20 0.20 0.31 2.0%
AREA
(ACRES) C2 C5 C10 C100
0.12 0.20 0.20 0.20 0.31 2%
0.45 0.95 0.95 0.95 1.00 100%
0.57 0.79 0.79 0.79 0.85 78.8%
COMPOSITE RUNOFF COEFFICIENTS
SUB-BASIN COMPOSITE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
PERCENT
IMPERVIOUSNESS
4.11
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
4.10
LANDSCAPE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS
PERCENT
IMPERVIOUSNESS
4.9
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
4.8
LANDSCAPE
ASPHALT/CONCRETE
4.7
MEDIUM DENSITY RESIDENTIAL
SUB-BASIN SURFACE CHARACTERISTICS
PERCENT
IMPERVIOUSNESS
12/14/2021 2:05 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 4.xlsm
PROJECT INFORMATION
PROJECT NAME:
PROJECT NO:
DESIGN BY:
REVIEWED BY:
JURISDICTION:
REPORT TYPE:
DATE:
C2 C5 C10 C100 % IMPERV
0.20 0.20 0.20 0.31 2%
0.95 0.95 0.95 1.00 100%
0.65 0.65 0.65 0.81 70%
0.85 0.85 0.85 1.00 80%
10.31 0.62 0.62 0.62 0.73 60.4%
LANDSCAPE
COMMERCIAL AREAS
FORT COLLINS
DRAINAGE
12/13/21
JURISDICTIONAL STANDARD
MONTAVA PHASE 1A
19.1354
E.BEDNAR
R.BYRNE
MEDIUM DENSITY RESIDENTIAL
ASPHALT/CONCRETE
TOTAL SITE COMPOSITE
AREA
(ACRES) C2 C5 C10 C100
0.13 0.20 0.20 0.20 0.31 2%
0.47 0.95 0.95 0.95 1.00 100%
0.60 0.79 0.79 0.79 0.85 78.8%
AREA
(ACRES) C2 C5 C10 C100
0.14 0.20 0.20 0.20 0.31 2%
0.64 0.95 0.95 0.95 1.00 100%
0.79 0.81 0.81 0.81 0.88 82.3%
AREA
(ACRES) C2 C5 C10 C100
0.15 0.20 0.20 0.20 0.31 2%
0.66 0.95 0.95 0.95 1.00 100%
0.81 0.81 0.81 0.81 0.87 81.9%
10.31 0.62 0.62 0.62 0.73 60.4%TOTAL SITE COMPOSITE
SUB-BASIN COMPOSITE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
4.14
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
4.13
LANDSCAPE
ASPHALT/CONCRETE
SUB-BASIN COMPOSITE
SUB-BASIN SURFACE CHARACTERISTICS
COMPOSITE RUNOFF COEFFICIENTS PERCENT
IMPERVIOUSNESS
4.12
LANDSCAPE
ASPHALT/CONCRETE
12/14/2021 2:06 PM
COMPOSITE_C-VALUES
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 4.xlsm
CALCULATED BY:JOB NO:
CHECKED BY:PROJECT:
DATE:
Is Project Urban? Yes
AREA LENGTH SLOPE ti LENGTH SLOPE VEL.tt COMP.TOT. LENGTH SLOPE IMP tc tc
ac ft ft/ft min ft ft/ft fps min tc ft ft/ft % First DP min
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)(16) (17)
4.1 0.20 0.81 95 0.0050 19.9 304 0.0050 15 1.06 4.8 24.7 399.0 0.01 2.0% 12.2 12.2
4.2 0.85 0.22 17 0.0200 1.5 150 0.0090 20 1.90 1.3 2.8 167.0 0.01 86.6% 10.9 5.0
4.3 0.88 0.10 15 0.0200 1.2 71 0.0090 20 1.90 0.6 1.8 86.0 0.01 90.2% 10.5 5.0
4.4 0.20 0.94 105 0.0120 15.7 380 0.0050 15 1.06 6.0 21.6 485.0 0.01 2.0% 12.7 12.7
4.5 0.77 1.02 35 0.0200 2.8 500 0.0100 20 2.00 4.2 7.0 535.0 0.01 80.1% 13.0 7.0
4.6 0.83 0.12 13 0.0200 1.4 130 0.0130 20 2.28 1.0 2.3 143.0 0.01 83.7% 10.8 5.0
4.7 0.65 2.97 200 0.0070 12.9 254 0.0070 20 1.67 2.5 15.5 454.0 0.01 70.0% 12.5 12.5
4.8 0.83 0.38 24 0.0020 4.1 250 0.0050 20 1.41 2.9 7.0 274.0 0.00 84.5% 11.5 7.0
4.9 0.85 0.39 24 0.0020 3.8 250 0.0050 20 1.41 2.9 6.7 274.0 0.00 87.4% 11.5 6.7
4.10 0.20 0.59 30 0.0400 5.6 278 0.0050 15 1.06 4.4 10.0 308.0 0.01 2.0% 11.7 10.0
4.11 0.79 0.57 30 0.0200 2.4 570 0.0050 20 1.41 6.7 9.2 600.0 0.01 78.8% 13.3 9.2
4.12 0.79 0.60 30 0.0200 2.4 570 0.0050 20 1.41 6.7 9.2 600.0 0.01 78.8% 13.3 9.2
4.13 0.81 0.79 30 0.0200 2.3 590 0.0140 20 2.37 4.2 6.4 620.0 0.01 82.3% 13.4 6.4
4.14 0.81 0.81 30 0.0200 2.3 506 0.0110 20 2.10 4.0 6.3 536.0 0.01 81.9% 13.0 6.3
*Velocity (V) = CvSw0.5
TABLE 6-2
*Table 6-2, UDFCD (V.1), Chapter 6, Page 6-5
in which: Cv = Conveyance Coefficient (See Table Above)
Sw = Watercourse Slope (ft/ft)
BASIN
DESIGN
POINT C5 Cv
Pond
DATA
SUB-BASIN
TIME (ti)(tt)
Paved Areas and Shallow Paved Swales 20
Heavy Meadow 2.5
Tillage / Field
Nearly Bare Ground 10
Grassed Waterway 15
5
Short Pasture and Lawns 7
Type of Land Surface Conveyance Coefficient, Cv
Pond
19.1354
MONTAVA PHASE 1A
STANDARD FORM SF-2
(RATIONAL METHOD PROCEDURE)
Pond
REMARKS
tc CHECK (URBANIZED BASINS)
E.BEDNAR
R.BYRNE
12/13/21
INITIAL/OVERLAND
TIME OF CONCENTRATION SUMMARY
TRAVEL TIME
TOC
12/14/2021 2:06 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 4.xlsm
CALCULATED BY:E.BEDNAR JOB NO:19.1354
CHECKED BY:R.BYRNE PROJECT:MONTAVA PHASE 1A
DATE:12/13/21 DESIGN STORM:2-YR
ONE-HR PRECIP:0
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
4.1 0.81 0.20 12.2 0.16 2.05 0.33
4.2 0.22 0.85 5.0 0.19 2.85 0.53
4.3 0.10 0.88 5.0 0.09 2.85 0.25
4.4 0.94 0.20 12.7 0.19 1.98 0.37
4.5 1.02 0.77 7.0 0.79 2.52 1.98
4.6 0.12 0.83 5.0 0.10 2.85 0.28
4.7 2.97 0.65 12.5 1.93 1.98 3.82
4.8 0.38 0.83 7.0 0.32 2.52 0.79
4.9 0.39 0.85 6.7 0.33 2.52 0.84
4.10 0.59 0.20 10.0 0.12 2.21 0.26
4.11 0.57 0.79 9.2 0.45 2.30 1.04
4.12 0.60 0.79 9.2 0.47 2.30 1.09
4.13 0.79 0.81 6.4 0.64 2.67 1.70
4.14 0.81 0.81 6.3 0.66 2.67 1.75
REMARKSAREA
(AC)
RUNOFF
COEFF
tc
(MIN)
BASIN DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF
tc
(MIN)
S(CxA)
(AC)
I
(IN/HR)
Q
(CFS)
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
CxA
(AC)
I
(IN/HR)
Q
(CFS)
2-YEAR
12/14/2021 2:06 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 4.xlsm
CALCULATED BY:E.BEDNAR JOB NO:19.1354
CHECKED BY:R.BYRNE PROJECT:MONTAVA PHASE 1A
DATE:12/13/21 DESIGN STORM:100-YR
ONE-HR PRECIP:0.00
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
4.1 0.81 0.31 12.2 0.25 7.16 1.79
4.2 0.22 0.91 5.0 0.20 9.95 1.99
4.3 0.10 0.93 5.0 0.09 9.95 0.93
4.4 0.94 0.31 12.7 0.29 6.92 2.02
4.5 1.02 0.87 7.0 0.89 8.80 7.81
4.6 0.12 0.89 5.0 0.11 9.95 1.06
4.7 2.97 0.81 12.5 2.41 6.92 16.65
4.8 0.38 0.89 7.0 0.34 8.80 2.98
4.9 0.39 0.91 6.7 0.35 8.80 3.12
4.10 0.59 0.31 10.0 0.18 7.72 1.41
4.11 0.57 0.85 9.2 0.49 8.03 3.92
4.12 0.60 0.85 9.2 0.51 8.03 4.10
4.13 0.79 0.88 6.4 0.69 9.31 6.44
4.14 0.81 0.87 6.3 0.70 9.31 6.56
REMARKSAREA
(AC)
RUNOFF
COEFF
tc
(MIN)
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
CxA
(AC)
I
(IN/HR)
Q
(CFS)
BASIN DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF
tc
(MIN)
S(CxA)
(AC)
I
(IN/HR)
Q
(CFS)
100-YEAR
12/14/2021 2:06 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 4.xlsm
PROJECT:
JOB NO:19.1354
DATE:12/13/21
DESIGN AREA %
Q2 Q100
POINT (ACRES) IMP.(CFS) (CFS)
4.1 0.81 2.0% 0.20 0.31 0.33 1.79
4.2 0.22 86.6% 0.85 0.91 0.53 1.99
4.3 0.10 90.2% 0.88 0.93 0.25 0.93
4.4 0.94 2.0% 0.20 0.31 0.37 2.02
4.5 1.02 80.1% 0.77 0.87 1.98 7.81
4.6 0.12 83.7% 0.83 0.89 0.28 1.06
4.7 2.97 70.0% 0.65 0.81 3.82 16.65
4.8 0.38 84.5% 0.83 0.89 0.79 2.98
4.9 0.39 87.4% 0.85 0.91 0.84 3.12
4.10 0.59 2.0% 0.20 0.31 0.26 1.41
4.11 0.57 78.8% 0.79 0.85 1.04 3.92
4.12 0.60 78.8% 0.79 0.85 1.09 4.10
4.13 0.79 82.3% 0.81 0.88 1.70 6.44
4.14 0.81 81.9% 0.81 0.87 1.75 6.56
10.31 60.4% 0.62 0.73 15.05 60.76
MONTAVA PHASE 1A
SITE COMPOSITE
BASIN
RUNOFF SUMMARY
C2 C100
RUNOFF_SUMMARY
12/14/2021 2:06 PM
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\RATIONAL\Rational BASIN 4.xlsm
BASINS AC IMP. C2 C100 Q2 Q100
1-16 5.95 67.6% 0.68 0.78 9.80 39.27
17-33 9.02 71.3% 0.70 0.81 11.20 46.34
TOTAL 14.97 69.9% 0.69 0.80 21.00 85.61
BASINS AC IMP. C2 C100 Q2 Q100
1-17 8.78 65.7% 0.65 0.77 13.43 54.38
18-35 5.70 70.5% 0.68 0.81 9.53 39.34
TOTAL 14.48 68.6% 0.67 0.79 22.96 93.72
BASINS AC IMP. C2 C100 Q2 Q100
TOTAL 10.3 60.4% 0.62 0.73 15.05 60.76
BASINS AC IMP. C2 C100 Q2 Q100
2.1-2.33
(POND E)14.97 69.9% 0.69 0.80 21.00 85.61
3.1-3.35
(POND A2)14.48 68.6% 0.67 0.79 22.96 93.72
4.1-4.14
(POND A1)10.31 60.4% 0.62 0.73 15.05 60.76
SITE TOTAL 39.76 66.9% 0.66 0.78 59.01 240.09
BASIN 3 (POND A2)
BASIN 4 (POND A1)
OVERALL BASIN COMPOSITE SUMMARY
BASIN 2 (POND E)
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
3.2 Runoff Coefficients
Page 4
3.2 Runoff Coefficients
Runoff coefficients used for the Rational Method are determined based on either overall land use or
surface type across the drainage area. For Overall Drainage Plan (ODP) submittals, when surface types
may not yet be known, land use shall be used to estimate flow rates and volumes. Table 3.2-1 lists the
runoff coefficients for common types of land uses in the City.
Table 3.2-1. Zoning Classification - Runoff Coefficients
Land Use Runoff Coefficient (C)
Residential
Urban Estate 0.30
Low Density 0.55
Medium Density 0.65
High Density 0.85
Commercial
Commercial 0.85
Industrial 0.95
Undeveloped
Open Lands,
Transition 0.20
Greenbelts,
Agriculture 0.20
Reference: For further guidance regarding zoning classifications, refer to the Land Use
Code, Article 4.
For a Project Development Plan (PDP) or Final Plan (FP) submittals, runoff coefficients must be based on
the proposed land surface types. Since the actual runoff coefficients may be different from those
specified in Table 3.2-1, Table 3.2-2 lists coefficients for the specific types of land surfaces.
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
3.2 Runoff Coefficients
Page 5
Table 3.2-2. Surface Type - Runoff Coefficients
Surface Type Runoff Coefficients
Hardscape or Hard Surface
Asphalt, Concrete 0.95
Rooftop 0.95
Recycled Asphalt 0.80
Gravel 0.50
Pavers 0.50
Landscape or Pervious Surface
Lawns, Sandy Soil, Flat Slope < 2% 0.10
Lawns, Sandy Soil, Avg Slope 2-7% 0.15
Lawns, Sandy Soil, Steep Slope >7% 0.20
Lawns, Clayey Soil, Flat Slope < 2% 0.20
Lawns, Clayey Soil, Avg Slope 2-7% 0.25
Lawns, Clayey Soil, Steep Slope >7% 0.35
3.2.1 Composite Runoff Coefficients
Drainage sub-basins are frequently composed of land that has multiple surface types or zoning
classifications. In such cases a composite runoff coefficient must be calculated for any given drainage
sub-basin.
The composite runoff coefficient is obtained using the following formula:
()
t
n
i
ii
A
xAC
C
∑
==1 Equation 5-2
Where: C = Composite Runoff Coefficient
Ci = Runoff Coefficient for Specific Area (Ai), dimensionless
Ai = Area of Surface with Runoff Coefficient of Ci, acres or square feet
n = Number of different surfaces to be considered
At = Total Area over which C is applicable, acres or square feet
3.2.2 Runoff Coefficient Frequency Adjustment Factor
The runoff coefficients provided in Table 3.2-1 and Table 3.2-2 are appropriate for use with the 2-year
storm event. For any analysis of storms with higher intensities, an adjustment of the runoff coefficient is
required due to the lessening amount of infiltration, depression retention, evapotranspiration and other
losses that have a proportionally smaller effect on high-intensity storm runoff. This adjustment is
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
3.3 Time of Concentration
Page 6
applied to the composite runoff coefficient. These frequency adjustment factors, Cf, are found in Table
3.2-3.
Table 3.2-3. Frequency Adjustment Factors
Storm Return Period
(years)
Frequency Adjustment
Factor (Cf)
2, 5, 10 1.00
25 1.10
50 1.20
100 1.25
3.3 Time of Concentration
3.3.1 Overall Equation
The next step to approximate runoff using the Rational Method is to estimate the Time of
Concentration, Tc, or the time for water to flow from the most remote part of the drainage sub-basin to
the design point under consideration.
The Time of Concentration is represented by the following equation:
𝐓𝐓𝐜𝐜=𝐓𝐓𝐢𝐢+𝐓𝐓𝐭𝐭 Equation 5-3
Where: Tc = Total Time of Concentration, minutes
Ti = Initial or Overland Flow Time of Concentration, minutes
Tt = Channelized Flow in Swale, Gutter or Pipe, minutes
3.3.2 Overland Flow Time
Overland flow, Ti, can be determined by the following equation:
𝐓𝐓𝐢𝐢=𝟏𝟏.𝟖𝟖𝟖𝟖(𝟏𝟏.𝟏𝟏−𝐂𝐂𝐂𝐂𝐂𝐂𝐟𝐟)√𝐋𝐋√𝐒𝐒𝟑𝟑 Equation 3.3-2
Where: C = Runoff Coefficient, dimensionless
Cf = Frequency Adjustment Factor, dimensionless
L = Length of Overland Flow, feet
S = Slope, percent
CXCF
PRODUCT OF CXCF
CANNOT EXCEED THE
VALUE OF 1
OVERLAND FLOW LENGTH
L=200’ MAX IN DEVELOPED AREAS
L=500’ MAX IN UNDEVELOPED
AREAS
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
3.4 Intensity-Duration-Frequency Curves for Rational Method
Page 8
Table 3.4-1. IDF Table for Rational Method
Duration
(min)
Intensity
2-year
(in/hr)
Intensity
10-year
(in/hr)
Intensity
100-year
(in/hr)
Duration
(min)
Intensity
2-year
(in/hr)
Intensity
10-year
(in/hr)
Intensity
100-year
(in/hr)
5 2.85 4.87 9.95
39 1.09 1.86 3.8
6 2.67 4.56 9.31
40 1.07 1.83 3.74
7 2.52 4.31 8.80
41 1.05 1.80 3.68
8 2.40 4.10 8.38
42 1.04 1.77 3.62
9 2.30 3.93 8.03
43 1.02 1.74 3.56
10 2.21 3.78 7.72
44 1.01 1.72 3.51
11 2.13 3.63 7.42
45 0.99 1.69 3.46
12 2.05 3.50 7.16
46 0.98 1.67 3.41
13 1.98 3.39 6.92
47 0.96 1.64 3.36
14 1.92 3.29 6.71
48 0.95 1.62 3.31
15 1.87 3.19 6.52
49 0.94 1.6 3.27
16 1.81 3.08 6.30
50 0.92 1.58 3.23
17 1.75 2.99 6.10
51 0.91 1.56 3.18
18 1.70 2.90 5.92
52 0.9 1.54 3.14
19 1.65 2.82 5.75
53 0.89 1.52 3.10
20 1.61 2.74 5.60
54 0.88 1.50 3.07
21 1.56 2.67 5.46
55 0.87 1.48 3.03
22 1.53 2.61 5.32
56 0.86 1.47 2.99
23 1.49 2.55 5.20
57 0.85 1.45 2.96
24 1.46 2.49 5.09
58 0.84 1.43 2.92
25 1.43 2.44 4.98
59 0.83 1.42 2.89
26 1.4 2.39 4.87
60 0.82 1.4 2.86
27 1.37 2.34 4.78
65 0.78 1.32 2.71
28 1.34 2.29 4.69
70 0.73 1.25 2.59
29 1.32 2.25 4.60
75 0.70 1.19 2.48
30 1.30 2.21 4.52
80 0.66 1.14 2.38
31 1.27 2.16 4.42
85 0.64 1.09 2.29
32 1.24 2.12 4.33
90 0.61 1.05 2.21
33 1.22 2.08 4.24
95 0.58 1.01 2.13
34 1.19 2.04 4.16
100 0.56 0.97 2.06
35 1.17 2.00 4.08
105 0.54 0.94 2.00
36 1.15 1.96 4.01
110 0.52 0.91 1.94
37 1.16 1.93 3.93
115 0.51 0.88 1.88
38 1.11 1.89 3.87
120 0.49 0.86 1.84
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
3.0 Rational Method
3.4 Intensity-Duration-Frequency Curves for Rational Method
Page 9
Figure 3.4-1. Rainfall IDF Curve – Fort Collins
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
4.0 SWMM
4.1 Input Parameters
Page 10
4.0 SWMM
This section is for project sites that require the use of the Stormwater Management Model (SWMM) to
determine storm hydrograph routing and is the only method that is able to assess the overall
performance of multiple detention basins in parallel or in series in a particular project site or watershed.
Reference: The theory and methodology for reservoir routing is not covered in this Manual
as this subject is well described in many hydrology reference books. The EPA SWMM
Reference Manuals, dated January 2016, have been utilized in preparing the information in
this section of the Manual.
4.1 Input Parameters
Table 4.1-1 provides required input values to be used for SWMM modeling.
Basin and conveyance element parameters must be computed based on the physical characteristics of
the site.
Table 4.1-1. SWMM Input Parameters
Depth of Storage
Impervious Areas 0.1 inches
Pervious Areas 0.3 inches
Infiltration Parameters
Maximum 0.51 in/hr
Minimum 0.50 in/hr
Decay Rate
0.0018 in/sec or
6.48 in/hr
Zero Detention Depth 1%
Manning's "n"
Pervious Surfaces 0.250
Impervious Surfaces 0.016
For Overall Drainage Plan (ODP) and Project Development Plan (PDP) submittals, when surface types
may not yet be known, land uses may be used to estimate impervious percentages. Table 4.1-2 lists the
percent imperviousness for common types of land uses in the City.
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
4.0 SWMM
4.1 Input Parameters
Page 11
Table 4.1-2. Land Use - Percent Impervious
Land Use
Percent Impervious
(%)
Residential
Urban Estate 30
Low Density 50
Medium Density 70
High Density 90
Commercial
Commercial 80
Industrial 90
Undeveloped
Open Lands, Transition 20
Greenbelts, Agriculture 2
Offsite Flow Analysis (when
Land Use not defined) 45
Reference: For further guidance regarding zoning classifications, refer to the Land Use
Code, Article 4.
For Final Plan (FP) submittals, impervious values must be based on the proposed land surface types.
Refer to Table 4.1-3 for recommended percent impervious values.
Table 4.1-3. Surface Type – Percent Impervious
Surface Type
Percent Impervious
(%)
Hardscape or Hard Surface
Asphalt, Concrete 100
Rooftop 90
Recycled Asphalt 80
Gravel 40
Pavers 40
Landscape or Pervious Surface
Playgrounds 25
Lawns, Sandy soil 2
Lawns, Clayey soil 2
FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5)
4.0 SWMM
4.1 Input Parameters
Page 12
The composite imperviousness is obtained using the following formula:
()
t
n
i
ii
A
xAI
I
∑
==1 Equation 5-6
Where: I = Composite Imperviousness, %
Ii = Imperviousness for Specific Area (Ai), %
Ai = Area of Surface with Imperviousness of Ii, acres or square feet
n = Number of different surfaces to be considered
At = Total Area over which I is applicable, acres or square feet
4.1.1 Intensity-Duration-Frequency Curves for SWMM
The hyetograph input option must be selected when creating SWMM input files. Hyetographs for the 2-
year, 5-year, 10-year, 25-year, 50-year, and 100-year Fort Collins rainfall events are provided in Table
4.1-4.
Table 4.1-4. IDF Table for SWMM
Duration
(min)
Intensity
2-year
(in/hr)
Intensity
5-year
(in/hr)
Intensity
10-year
(in/hr)
Intensity
25-year
(in/hr)
Intensity
50-year
(in/hr)
Intensity
100-year
(in/hr)
5 0.29 0.40 0.49 0.63 0.79 1.00
10 0.33 0.45 0.56 0.72 0.90 1.14
15 0.38 0.53 0.65 0.84 1.05 1.33
20 0.64 0.89 1.09 1.41 1.77 2.23
25 0.81 1.13 1.39 1.80 2.25 2.84
30 1.57 2.19 2.69 3.48 4.36 5.49
35 2.85 3.97 4.87 6.30 7.90 9.95
40 1.18 1.64 2.02 2.61 3.27 4.12
45 0.71 0.99 1.21 1.57 1.97 2.48
50 0.42 0.58 0.71 0.92 1.16 1.46
55 0.35 0.49 0.60 0.77 0.97 1.22
60 0.30 0.42 0.52 0.67 0.84 1.06
65 0.20 0.28 0.39 0.62 0.79 1.00
70 0.19 0.27 0.37 0.59 0.75 0.95
75 0.18 0.25 0.35 0.56 0.72 0.91
80 0.17 0.24 0.34 0.54 0.69 0.87
85 0.17 0.23 0.32 0.52 0.66 0.84
90 0.16 0.22 0.31 0.50 0.64 0.81
95 0.15 0.21 0.30 0.48 0.62 0.78
100 0.15 0.20 0.29 0.47 0.60 0.75
105 0.14 0.19 0.28 0.45 0.58 0.73
110 0.14 0.19 0.27 0.44 0.56 0.71
115 0.13 0.18 0.26 0.42 0.54 0.69
120 0.13 0.18 0.25 0.41 0.53 0.67
Montava – Phase G PDP
December 14, 2021
C-WQ/Detention Calculations
********************
Subcatchment Summary
********************
Name Area Width %Imperv %Slope Rain Gage Outlet
-----------------------------------------------------------------------------------------------------------
SB_A1 10.30 348.00 5.00 1.3000 1 A1
SB_A2 14.50 432.00 5.00 1.0000 1 A2
SB_E 14.80 394.00 5.00 1.8000 1 E
***************************
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
--------------------------------------------------------------------------------------------------------
SB_A1 0.98 0.00 0.00 0.93 0.05 0.01 1.46 0.047
SB_A2 0.98 0.00 0.00 0.93 0.05 0.02 2.03 0.047
SB_E 0.98 0.00 0.00 0.93 0.05 0.02 2.09 0.047
HISTORIC 2-YEAR SWMM OUTPUT
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.010)
--------------------------------------------------------------
Model 2 of 3
......................................
Selected Plan Improvements:
*************
Element Count
*************
Number of rain gages ...... 4
Number of subcatchments ... 41
Number of nodes ........... 89
Number of links ........... 83
Number of pollutants ...... 0
Number of land uses ....... 0
****************
Raingage Summary
****************
Data Recording
Name Data Source Type Interval
------------------------------------------------------------------------
1 1-100yr INTENSITY 5 min.
2 2 INTENSITY 5 min.
3 3 INTENSITY 5 min.
WQ WQ INTENSITY 5 min.
********************
Subcatchment Summary
********************
Name Area Width %Imperv %Slope Rain Gage Outlet
-----------------------------------------------------------------------------------------------------------
SB_A1 10.30 348.00 61.00 1.3000 1 A1
SB_A2 14.50 432.00 68.00 1.0000 1 A2
SB_D 47.34 1014.00 60.00 0.5000 1 D
SB_E 14.80 394.00 70.00 1.8000 1 E
SB_F 43.30 1433.00 60.00 0.5000 1 F
SB_G1 17.50 500.00 80.00 0.5000 1 427
100-YEAR SWMM OUTPUT
SB_G1_EX 26.30 1040.00 5.00 1.5000 1 427
SB_G2 10.02 432.00 80.00 0.5000 1 G2
SB17 52.30 4140.00 5.00 3.9000 1 417
SB18 137.60 5994.00 75.00 1.0000 1 Storage_18
SB19 82.00 3570.00 75.00 2.5000 1 Storeage_19
SB20_2 45.61 7250.00 45.00 0.5000 1 Storage_20_3
SB20_3 96.10 14080.00 75.00 2.0000 1 Storage_20_1
SB20_4 19.90 3560.00 25.00 0.5000 1 Storage_20_2
SB200 33.60 1460.00 5.00 1.6000 1 826
SB201 14.80 3220.00 5.00 2.0000 1 437
SB21 22.60 2190.00 5.00 2.9000 1 421
SB24 33.70 9790.00 45.00 3.3000 1 424
SB25 129.10 5630.00 5.00 0.7000 1 725
SB26 155.10 6756.00 5.00 2.0000 1 726
SB28 125.90 5480.00 9.00 3.1000 1 28
SB29 268.80 21290.00 29.00 0.6000 1 729
SB30 33.50 4870.00 49.00 1.5000 1 430
SB31 184.50 8040.00 7.00 2.1000 1 31
SB32 160.50 1506.00 6.00 1.5000 1 432
SB33.1 33.90 1480.00 8.00 2.1000 1 433
SB33.2 38.00 5520.00 58.00 2.1000 1 433
SB33.3 84.00 12200.00 53.00 2.1000 1 433
SB33.4 41.70 6050.00 53.00 2.1000 1 433
SB34 128.50 6220.00 9.00 1.0000 1 834
SB37 34.60 3770.00 23.00 1.8000 1 37
SB38 290.70 12660.00 5.00 2.8000 1 38
SB39 17.10 2480.00 5.00 30.8000 1 839
SB40 110.70 16070.00 53.00 2.7000 1 440
SB41 132.60 38510.00 29.00 1.7000 1 441
SB42 54.00 2350.00 5.00 1.3000 1 42
SB43 37.80 2060.00 40.00 1.9000 1 43
SB45 54.30 2370.00 5.00 1.0000 1 45
SB46 135.80 5920.00 18.00 3.6000 1 46
SB50 167.70 7310.00 5.00 1.9000 2 50
SB51 267.80 11670.00 5.00 4.6000 2 51
************
Node Summary
************
Invert Max. Ponded External
Name Type Elev. Depth Area Inflow
100-YEAR SWMM OUTPUT
-------------------------------------------------------------------------------
7 JUNCTION 5113.00 10.00 0.0 Yes
18 JUNCTION 4990.22 5.00 0.0
19 JUNCTION 5010.00 10.00 0.0
28 JUNCTION 5017.03 7.00 0.0
31 JUNCTION 4998.22 7.00 0.0
32 JUNCTION 4995.37 7.00 0.0
37 JUNCTION 5032.56 5.00 0.0
38 JUNCTION 5037.85 7.00 0.0
42 JUNCTION 5055.72 5.00 0.0
43 JUNCTION 5094.93 5.00 0.0
45 JUNCTION 5075.96 5.00 0.0
46 JUNCTION 5083.14 7.00 0.0
50 JUNCTION 5089.88 7.00 0.0
51 JUNCTION 5088.52 7.00 0.0
427.1 JUNCTION 4991.00 10.00 0.0
427.2 JUNCTION 4998.00 10.00 0.0
725 JUNCTION 4980.35 6.50 0.0
726 JUNCTION 4984.00 7.00 0.0
729 JUNCTION 5000.16 10.00 0.0
730 JUNCTION 4989.47 12.00 0.0
819 JUNCTION 4980.00 5.00 0.0
822.1 JUNCTION 4989.98 10.00 0.0
822.2 JUNCTION 4991.21 7.00 0.0
826 JUNCTION 4986.00 7.00 0.0
828 JUNCTION 4992.70 7.00 0.0
829 JUNCTION 4984.74 10.00 0.0
831 JUNCTION 4993.94 7.00 0.0
833.1 JUNCTION 4996.51 10.00 0.0
833.2 JUNCTION 4999.49 10.00 0.0
834 JUNCTION 5019.03 7.00 0.0
839 JUNCTION 5028.25 10.00 0.0
841 JUNCTION 5003.34 20.12 0.0
842 JUNCTION 5034.81 15.00 0.0
843 JUNCTION 5032.85 7.00 0.0
844 JUNCTION 5031.02 10.00 0.0
845 JUNCTION 5048.19 15.00 0.0
850 JUNCTION 5074.76 10.00 0.0
855 JUNCTION 4983.94 15.00 0.0
856 JUNCTION 4982.05 15.00 0.0
857 JUNCTION 4982.05 5.00 0.0
940 JUNCTION 5015.45 16.10 0.0
100-YEAR SWMM OUTPUT
941 JUNCTION 5008.40 12.00 0.0
942 JUNCTION 5009.45 12.00 0.0
7240 JUNCTION 5023.00 7.00 0.0
7244 JUNCTION 5055.39 5.00 0.0 Yes
7251 JUNCTION 5082.97 7.00 0.0
7430 JUNCTION 4992.90 9.00 0.0
7431 JUNCTION 4991.94 12.00 0.0
7432 JUNCTION 4993.90 7.00 0.0
7435 JUNCTION 5028.27 10.00 0.0 Yes
7436 JUNCTION 5025.81 10.00 0.0 Yes
7437 JUNCTION 5024.39 7.00 0.0
7441 JUNCTION 5059.87 2.00 0.0
7446 JUNCTION 5069.02 2.00 0.0
7456 JUNCTION 5107.91 15.00 0.0 Yes
417 OUTFALL 4980.32 0.00 0.0
443 OUTFALL 5072.27 5.00 0.0
900 OUTFALL 4987.00 8.00 0.0
901 OUTFALL 4974.02 15.00 0.0
902 OUTFALL 4973.21 0.00 0.0
903 OUTFALL 4977.40 0.00 0.0
904 OUTFALL 4973.14 0.00 0.0
907 OUTFALL 4972.52 0.00 0.0
421 OUTFALL 4990.00 0.00 0.0
2 STORAGE 4991.00 6.00 0.0
424 STORAGE 5010.00 8.00 0.0
425 STORAGE 4979.00 4.50 0.0
426 STORAGE 4981.00 8.78 0.0
427 STORAGE 4989.00 7.40 0.0
428 STORAGE 4997.00 6.00 0.0
430 STORAGE 4992.90 5.00 0.0
432 STORAGE 4993.90 7.10 0.0
433 STORAGE 4999.00 7.51 0.0
437 STORAGE 5024.70 4.10 0.0
438 STORAGE 5027.50 5.00 0.0
440 STORAGE 5025.00 8.85 0.0
441 STORAGE 5061.76 8.70 0.0
446 STORAGE 5070.00 100.00 0.0
A1 STORAGE 4999.66 6.00 0.0
A2 STORAGE 5003.69 8.50 0.0
D STORAGE 4999.00 2.50 0.0
E STORAGE 5000.00 13.00 0.0
F STORAGE 4991.00 3.00 0.0
100-YEAR SWMM OUTPUT
G2 STORAGE 4989.98 7.50 0.0
Storage_18 STORAGE 4992.00 100.00 0.0
Storage_20_1 STORAGE 4983.00 100.00 0.0
Storage_20_2 STORAGE 5002.00 4.00 0.0
Storage_20_3 STORAGE 5009.00 9.00 0.0
Storeage_19 STORAGE 4984.00 10.00 0.0
************
Link Summary
************
Name From Node To Node Type Length %Slope Roughness
---------------------------------------------------------------------------------------------
18 18 819 CONDUIT 695.6 1.4694 0.0400
22 Storage_20_2 900 CONDUIT 1800.0 0.5556 0.0500
23 7 7456 CONDUIT 50.0 0.1800 0.0350
25 725 425 CONDUIT 1037.2 0.1302 0.0160
26 726 426 CONDUIT 2114.1 0.1419 0.0350
26.1 427.1 427 CONDUIT 1415.0 0.1413 0.0350
26.2 427.2 F CONDUIT 1380.0 0.5073 0.0350
28 28 428 CONDUIT 2035.1 0.9843 0.0350
29 729 829 CONDUIT 3322.3 0.4641 0.0350
30 730 829 CONDUIT 1967.1 0.2405 0.0350
31 31 7431 CONDUIT 2371.5 0.2648 0.0350
32.1 32 432 CONDUIT 2162.0 0.0680 0.0350
32.2 833.2 32 CONDUIT 1670.0 0.2467 0.0350
34 834 940 CONDUIT 1764.8 0.2029 0.0350
37 37 437 CONDUIT 1030.4 0.7628 0.0400
38 38 438 CONDUIT 582.5 1.7771 0.0350
41 7441 841 CONDUIT 3355.4 1.1448 0.0130
42 42 842 CONDUIT 1275.7 1.6393 0.0400
43 43 443 CONDUIT 1412.3 1.6047 0.0350
45 45 845 CONDUIT 690.3 4.0261 0.0400
46 46 446 CONDUIT 1763.1 0.7453 0.0350
50 50 850 CONDUIT 1749.6 0.8642 0.0350
51 51 7251 CONDUIT 1942.3 0.2857 0.0350
70 856 901 CONDUIT 1380.3 0.5818 0.0350
71 822.1 855 CONDUIT 1559.6 0.3873 0.0350
72.1 822.2 822.1 CONDUIT 491.4 0.2503 0.0130
72.2 828 822.2 CONDUIT 595.5 0.2502 0.0130
73.1 831 828 CONDUIT 496.9 0.2495 0.0130
73.2 833.1 831 CONDUIT 683.5 0.3760 0.0130
100-YEAR SWMM OUTPUT
74.1 833.2 833.1 CONDUIT 1795.0 0.1660 0.0350
74.2 841 833.2 CONDUIT 1540.0 0.2500 0.0350
75 839 841 CONDUIT 2027.9 1.2285 0.0350
76 844 839 CONDUIT 505.4 0.5481 0.0350
77 845 842 CONDUIT 2134.3 0.6269 0.0350
78 850 845 CONDUIT 1440.1 1.8453 0.0350
79 7456 850 CONDUIT 2859.4 1.1594 0.0350
153 19 A1 CONDUIT 992.6 1.0418 0.0350
218 857 819 CONDUIT 1522.9 0.1346 0.0400
227 826 726 CONDUIT 1311.2 0.1525 0.0350
229 829 725 CONDUIT 1117.8 0.3927 0.0160
231 7431 426 CONDUIT 3227.2 0.3390 0.0350
232 7432 826 CONDUIT 1794.4 0.4403 0.0350
234 942 7431 CONDUIT 2396.1 0.7308 0.0350
235 7435 729 CONDUIT 2906.9 0.9671 0.0350
236 7436 834 CONDUIT 400.0 1.6952 0.0100
237 7437 834 CONDUIT 1977.3 0.2711 0.0350
240 7240 833.1 CONDUIT 2465.9 1.0743 0.0350
242 843 438 CONDUIT 50.0 10.7618 0.0350
244 7244 437 CONDUIT 3820.9 0.8032 0.0350
246 7446 845 CONDUIT 680.3 3.0633 0.0130
251 7251 845 CONDUIT 2547.2 1.3655 0.0350
730 7430 730 CONDUIT 1967.1 0.1744 0.0350
819 819 902 CONDUIT 625.0 1.0865 0.0130
842D 842 843 CONDUIT 100.0 1.9604 0.0350
842L 842 844 CONDUIT 250.0 1.5162 0.0350
855D 855 857 CONDUIT 50.0 3.7827 0.0400
855L 855 856 CONDUIT 50.0 3.7827 0.0350
940D 940 941 CONDUIT 70.0 16.1346 0.0350
940L 940 942 CONDUIT 564.5 1.0629 0.0350
941 941 730 CONDUIT 1870.1 1.0123 0.0350
446_OUT 446 7446 ORIFICE
D_OUT D 427.2 ORIFICE
F_OUT F 427.1 ORIFICE
G2_OUT G2 822.1 ORIFICE
19 Storage_20_3 Storage_20_2 WEIR
1 Storage_20_1 903 OUTLET
424_OUT 424 19 OUTLET
425_OUT 425 907 OUTLET
426_OUT 426 904 OUTLET
427_OUT 427 826 OUTLET
428_OUT 428 831 OUTLET
100-YEAR SWMM OUTPUT
430_OUT 430 7430 OUTLET
432_OUT 432 7432 OUTLET
433_OUT 433 833.1 OUTLET
437_OUT 437 7437 OUTLET
438_Out 438 437 OUTLET
440_OUT 440 7240 OUTLET
441_OUT 441 7441 OUTLET
9 Storage_18 18 OUTLET
A1_OUT A1 822.1 OUTLET
A2_OUT A2 822.2 OUTLET
E_OUT E 828 OUTLET
OL1 Storeage_19 855 OUTLET
*********************
Cross Section Summary
*********************
Full Full Hyd. Max. No. of Full
Conduit Shape Depth Area Rad. Width Barrels Flow
---------------------------------------------------------------------------------------
18 TRAPEZOIDAL 5.00 2500.00 2.50 1000.00 1 20737.04
22 TRAPEZOIDAL 3.00 465.00 1.52 305.00 1 1364.31
23 TRAPEZOIDAL 10.00 450.00 5.15 85.00 1 2415.80
25 4:0:0:0.016:0.5:13:6:3:0.035:6 6.50 242.00 1.37 67.00 1 999.81
26 0:2:2:0.035:2:8:100:100:0.06:5 7.00 2548.00 1.17 1008.00 1 4519.35
26.1 TRAPEZOIDAL 10.00 500.00 5.41 90.00 1 2458.83
26.2 TRAPEZOIDAL 10.00 500.00 5.41 90.00 1 4658.05
28 0:2:2:0.035:2:8:50:50:0.06:5 7.00 1298.00 1.23 508.00 1 6259.70
29 5:10:10:0.035:5:105:80:100:0.045:5 10.00 3050.00 2.96 1005.00 1 18206.28
30 10:4:4:0.035:4:42:100:100:0.045:5 9.00 2814.00 2.19 1042.00 1 9891.18
31 2:2:2:0.035:2:10:100:100:0.06:5 7.00 2562.00 1.19 1010.00 1 6282.45
32.1 2:2:2:0.035:2:10:100:60:0.06:5 7.00 2062.00 1.21 810.00 1 2590.17
32.2 2:2:2:0.035:2:10:100:60:0.06:5 7.00 2062.00 1.21 810.00 1 4933.88
34 2:2:2:0.035:2:10:100:100:0.06:5 7.00 2562.00 1.19 1010.00 1 5498.62
37 TRAPEZOIDAL 5.00 2505.00 2.50 1001.00 1 14981.29
38 0:2:2:0.035:2:8:100:100:0.06:5 7.00 2548.00 1.17 1008.00 1 15993.17
41 CIRCULAR 2.00 3.14 0.50 2.00 1 24.20
42 TRAPEZOIDAL 5.00 1375.00 2.50 550.00 1 12045.88
43 TRAPEZOIDAL 5.00 1250.00 2.50 500.00 1 12382.00
45 TRAPEZOIDAL 5.00 2500.00 2.50 1000.00 1 34325.95
46 0:2:2:0.035:2:8:40:80:0.06:5 7.00 1548.00 1.21 608.00 1 6429.00
50 0:2:2:0.035:2:8:100:100:0.06:5 7.00 2548.00 1.17 1008.00 1 11153.03
100-YEAR SWMM OUTPUT
51 0:2:2:0.035:2:8:25:25:0.06:5 7.00 673.00 1.34 258.00 1 1852.28
70 TRAPEZOIDAL 15.00 483.75 7.97 49.50 1 6248.26
71 TRAPEZOIDAL 10.00 280.00 5.85 41.00 1 2400.90
72.1 CIRCULAR 7.00 38.48 1.75 7.00 1 319.61
72.2 CIRCULAR 7.00 38.48 1.75 7.00 1 319.55
73.1 CIRCULAR 7.00 38.48 1.75 7.00 1 319.13
73.2 CIRCULAR 7.00 38.48 1.75 7.00 1 391.73
74.1 TRAPEZOIDAL 10.00 325.00 6.24 45.00 1 1905.91
74.2 TRAPEZOIDAL 10.00 325.00 6.24 45.00 1 2338.83
75 TRAPEZOIDAL 10.00 380.00 6.57 51.00 1 6275.37
76 TRAPEZOIDAL 10.00 390.00 6.56 53.00 1 4294.00
77 TRAPEZOIDAL 15.00 753.75 9.37 70.50 1 11265.02
78 TRAPEZOIDAL 10.00 395.00 6.13 59.00 1 7632.51
79 TRAPEZOIDAL 5.00 176.25 3.80 43.50 1 1963.34
153 TRAPEZOIDAL 7.00 266.00 3.93 66.00 1 2869.54
218 TRAPEZOIDAL 5.00 2500.00 2.50 1000.00 1 6276.52
227 0:2:2:0.035:2:8:100:100:0.06:5 7.00 2548.00 1.17 1008.00 1 4685.53
229 4:0:0:0.016:.5:13:6:3:0.035:5 5.50 179.50 1.21 58.00 1 1183.77
231 2:2:2:0.035:2:10:50:100:0.06:10 12.00 7612.00 2.31 1510.00 1 32837.73
232 0:2:2:0.035:2:8:100:100:0.06:5 7.00 2548.00 1.17 1008.00 1 7960.39
234 2:2:2:0.035:2:10:5:10:0.06:10 12.00 862.00 3.00 160.00 1 6511.30
235 5:10:10:0.035:5:105:80:100:0.045:5 10.00 3050.00 2.96 1005.00 1 26279.77
236 DUMMY 0.00 0.00 0.00 0.00 1 0.00
237 0:2:2:0.035:2:8:100:100:0.06:5 7.00 2548.00 1.17 1008.00 1 6246.33
240 0:2:2:0.035:2:8:80:100:0.06:5 7.00 2298.00 1.17 908.00 1 11255.94
242 0:2:2:0.035:2:8:100:100:0.06:5 7.00 2548.00 1.17 1008.00 1 39356.84
244 TRAPEZOIDAL 5.00 125.00 2.70 45.00 1 923.14
246 CIRCULAR 2.00 3.14 0.50 2.00 1 39.59
251 0:2:2:0.035:2:8:1:50:0.06:5 7.00 685.50 1.33 263.00 1 4103.30
730 10:4:4:0.035:4:42:100:100:0.045:5 9.00 2814.00 2.19 1042.00 1 8422.95
819 DUMMY 0.00 0.00 0.00 0.00 1 0.00
842D TRAPEZOIDAL 7.00 434.00 4.13 104.00 1 6638.04
842L TRAPEZOIDAL 10.00 390.00 6.56 53.00 1 7141.86
855D TRAPEZOIDAL 5.00 575.00 2.67 215.00 1 7998.55
855L TRAPEZOIDAL 15.00 483.75 7.97 49.50 1 15932.55
940D 2:2:2:0.035:2:10:5:10:0.06:10 12.00 862.00 3.00 160.00 1 30594.95
940L 2:2:2:0.035:2:10:5:10:0.06:10 12.00 862.00 3.00 160.00 1 7852.84
941 2:2:2:0.035:2:10:5:10:0.06:10 12.00 862.00 3.00 160.00 1 7663.46
****************
100-YEAR SWMM OUTPUT
0.8464 0.8634 0.8805 0.8976 0.9147
0.9317 0.9488 0.9659 0.9829 1.0000
*********************************************************
NOTE: The summary statistics displayed in this report are
based on results found at every computational time step,
not just on results from each reporting time step.
*********************************************************
****************
Analysis Options
****************
Flow Units ............... CFS
Process Models:
Rainfall/Runoff ........ YES
RDII ................... NO
Snowmelt ............... NO
Groundwater ............ NO
Flow Routing ........... YES
Ponding Allowed ........ YES
Water Quality .......... NO
Infiltration Method ...... HORTON
Flow Routing Method ...... DYNWAVE
Starting Date ............ JAN-28-2013 00:00:00
Ending Date .............. JAN-30-2013 06:00:00
Antecedent Dry Days ...... 0.0
Report Time Step ......... 00:01:00
Wet Time Step ............ 00:01:00
Dry Time Step ............ 01:00:00
Routing Time Step ........ 5.00 sec
Variable Time Step ....... YES
Maximum Trials ........... 8
Number of Threads ........ 1
Head Tolerance ........... 0.005000 ft
************************** Volume Depth
Runoff Quantity Continuity acre-feet inches
************************** --------- -------
Total Precipitation ...... 1032.994 3.636
Evaporation Loss ......... 0.000 0.000
100-YEAR SWMM OUTPUT
Infiltration Loss ........ 417.324 1.469
Surface Runoff ........... 609.102 2.144
Final Storage ............ 6.777 0.024
Continuity Error (%) ..... -0.020
************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 0.000 0.000
Wet Weather Inflow ....... 609.102 198.485
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.000 0.000
External Inflow .......... 2760.608 899.585
External Outflow ......... 2172.316 707.882
Flooding Loss ............ 538.369 175.436
Evaporation Loss ......... 0.000 0.000
Exfiltration Loss ........ 0.000 0.000
Initial Stored Volume .... 5.282 1.721
Final Stored Volume ...... 700.498 228.268
Continuity Error (%) ..... -1.072
*************************
Highest Continuity Errors
*************************
Node 446 (22.02%)
Node 437 (15.37%)
Node 726 (13.65%)
Node 432 (13.06%)
Node 428 (11.49%)
***************************
Time-Step Critical Elements
***************************
Link 23 (100.00%)
********************************
Highest Flow Instability Indexes
********************************
100-YEAR SWMM OUTPUT
Link 855D (83)
Link 855L (83)
Link 71 (83)
Link 9 (71)
Link 18 (70)
*************************
Routing Time Step Summary
*************************
Minimum Time Step : 1.29 sec
Average Time Step : 2.88 sec
Maximum Time Step : 5.00 sec
Percent in Steady State : 0.00
Average Iterations per Step : 2.01
Percent Not Converging : 0.04
***************************
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
--------------------------------------------------------------------------------------------------------
SB_A1 3.67 0.00 0.00 0.72 2.89 0.81 56.10 0.788
SB_A2 3.67 0.00 0.00 0.60 3.01 1.18 76.95 0.819
SB_D 3.67 0.00 0.00 0.91 2.70 3.47 172.20 0.737
SB_E 3.67 0.00 0.00 0.53 3.07 1.23 85.56 0.836
SB_F 3.67 0.00 0.00 0.82 2.79 3.28 193.79 0.760
SB_G1 3.67 0.00 0.00 0.37 3.22 1.53 84.50 0.879
SB_G1_EX 3.67 0.00 0.00 2.02 1.65 1.18 33.21 0.449
SB_G2 3.67 0.00 0.00 0.34 3.25 0.88 58.72 0.886
SB17 3.67 0.00 0.00 1.59 2.08 2.95 139.52 0.566
SB18 3.67 0.00 0.00 0.41 3.18 11.89 888.12 0.867
SB19 3.67 0.00 0.00 0.39 3.21 7.14 603.74 0.874
SB20_2 3.67 0.00 0.00 0.89 2.74 3.39 267.98 0.746
SB20_3 3.67 0.00 0.00 0.35 3.24 8.47 862.13 0.884
SB20_4 3.67 0.00 0.00 1.25 2.40 1.30 84.34 0.653
SB200 3.67 0.00 0.00 1.96 1.71 1.56 45.65 0.465
100-YEAR SWMM OUTPUT
SB201 3.67 0.00 0.00 1.44 2.22 0.89 61.16 0.606
SB21 3.67 0.00 0.00 1.57 2.09 1.28 62.49 0.570
SB24 3.67 0.00 0.00 0.77 2.86 2.62 280.13 0.779
SB25 3.67 0.00 0.00 2.15 1.52 5.32 139.79 0.413
SB26 3.67 0.00 0.00 1.91 1.75 7.39 225.58 0.478
SB28 3.67 0.00 0.00 1.73 1.93 6.60 259.54 0.526
SB29 3.67 0.00 0.00 1.34 2.30 16.78 999.81 0.627
SB30 3.67 0.00 0.00 0.77 2.85 2.60 231.26 0.778
SB31 3.67 0.00 0.00 1.85 1.81 9.07 309.06 0.494
SB32 3.67 0.00 0.00 2.68 0.98 4.29 122.41 0.268
SB33.1 3.67 0.00 0.00 1.83 1.84 1.69 60.20 0.500
SB33.2 3.67 0.00 0.00 0.61 3.00 3.10 298.79 0.818
SB33.3 3.67 0.00 0.00 0.69 2.93 6.68 628.35 0.798
SB33.4 3.67 0.00 0.00 0.69 2.93 3.31 311.86 0.798
SB34 3.67 0.00 0.00 1.91 1.75 6.10 213.00 0.476
SB37 3.67 0.00 0.00 1.26 2.39 2.25 147.82 0.651
SB38 3.67 0.00 0.00 1.84 1.82 14.39 469.06 0.497
SB39 3.67 0.00 0.00 1.34 2.33 1.08 115.30 0.635
SB40 3.67 0.00 0.00 0.68 2.93 8.82 848.72 0.800
SB41 3.67 0.00 0.00 1.03 2.61 9.41 878.27 0.712
SB42 3.67 0.00 0.00 2.00 1.66 2.43 69.13 0.452
SB43 3.67 0.00 0.00 1.05 2.58 2.65 185.32 0.702
SB45 3.67 0.00 0.00 2.06 1.60 2.36 64.69 0.436
SB46 3.67 0.00 0.00 1.50 2.15 7.93 410.22 0.586
SB50 3.41 0.00 0.00 1.89 1.52 6.92 210.28 0.446
SB51 3.41 0.00 0.00 1.72 1.68 12.25 443.48 0.494
******************
Node Depth Summary
******************
---------------------------------------------------------------------------------
Average Maximum Maximum Time of Max Reported
Depth Depth HGL Occurrence Max Depth
Node Type Feet Feet Feet days hr:min Feet
---------------------------------------------------------------------------------
7 JUNCTION 2.92 2.96 5115.96 0 00:00 2.92
18 JUNCTION 0.32 0.47 4990.69 0 06:51 0.47
19 JUNCTION 0.08 0.69 5010.69 0 07:20 0.69
28 JUNCTION 0.19 3.79 5020.82 0 06:50 3.79
31 JUNCTION 0.32 3.76 5001.98 0 07:02 3.76
100-YEAR SWMM OUTPUT
32 JUNCTION 3.39 3.66 4999.03 1 07:54 3.66
37 JUNCTION 0.06 0.86 5033.42 0 06:40 0.86
38 JUNCTION 0.26 3.15 5041.00 0 06:50 3.15
42 JUNCTION 0.05 0.69 5056.41 0 06:53 0.69
43 JUNCTION 0.04 0.98 5095.91 0 06:41 0.98
45 JUNCTION 0.03 0.46 5076.42 0 06:51 0.46
46 JUNCTION 0.31 3.88 5087.02 0 06:42 3.88
50 JUNCTION 0.17 3.15 5093.03 0 06:59 3.15
51 JUNCTION 0.24 5.55 5094.07 0 06:55 5.55
427.1 JUNCTION 1.10 1.84 4992.84 0 12:45 1.84
427.2 JUNCTION 0.17 0.45 4998.45 0 08:50 0.45
725 JUNCTION 1.13 5.59 4985.94 0 09:18 5.59
726 JUNCTION 4.32 5.46 4989.46 0 20:03 5.46
729 JUNCTION 0.38 3.97 5004.13 0 06:47 3.97
730 JUNCTION 0.60 3.61 4993.08 0 09:19 3.61
819 JUNCTION 0.00 0.00 4980.00 0 09:07 0.00
822.1 JUNCTION 2.66 3.62 4993.60 0 08:43 3.62
822.2 JUNCTION 2.93 4.37 4995.58 0 08:43 4.37
826 JUNCTION 2.62 3.46 4989.46 0 20:08 3.46
828 JUNCTION 3.02 4.72 4997.42 0 08:42 4.72
829 JUNCTION 0.75 4.32 4989.06 0 09:18 4.32
831 JUNCTION 3.03 4.84 4998.78 0 08:42 4.84
833.1 JUNCTION 2.74 4.03 5000.54 0 08:58 4.03
833.2 JUNCTION 2.02 3.15 5002.64 0 07:40 3.15
834 JUNCTION 3.09 5.16 5024.19 0 08:49 5.16
839 JUNCTION 1.11 2.08 5030.33 0 07:18 2.08
841 JUNCTION 2.09 4.09 5007.43 0 07:27 4.09
842 JUNCTION 1.05 2.33 5037.14 0 07:40 2.33
843 JUNCTION 2.17 2.86 5035.71 0 07:40 2.86
844 JUNCTION 1.55 2.71 5033.73 0 08:29 2.71
845 JUNCTION 2.17 4.17 5052.36 0 07:35 4.17
850 JUNCTION 1.65 2.71 5077.47 0 07:23 2.71
855 JUNCTION 0.64 0.99 4984.93 0 08:44 0.99
856 JUNCTION 1.34 2.01 4984.06 0 08:46 2.01
857 JUNCTION 1.67 2.31 4984.36 0 09:07 2.31
940 JUNCTION 3.09 6.39 5021.84 0 09:07 6.39
941 JUNCTION 0.65 3.95 5012.35 0 09:06 3.95
942 JUNCTION 3.53 7.60 5017.05 0 09:14 7.60
7240 JUNCTION 0.72 0.82 5023.82 0 15:25 0.82
7244 JUNCTION 0.14 3.19 5058.58 0 07:22 3.19
7251 JUNCTION 0.21 3.69 5086.66 0 07:11 3.69
7430 JUNCTION 0.22 1.62 4994.52 0 07:26 1.62
100-YEAR SWMM OUTPUT
7431 JUNCTION 2.92 4.82 4996.76 0 09:31 4.82
7432 JUNCTION 1.30 2.12 4996.02 1 08:27 2.12
7435 JUNCTION 0.25 2.58 5030.85 0 08:42 2.58
7436 JUNCTION 0.00 0.00 5025.81 0 00:00 0.00
7437 JUNCTION 1.58 3.25 5027.64 0 08:31 3.25
7441 JUNCTION 0.52 0.63 5060.50 0 08:26 0.63
7446 JUNCTION 0.34 1.03 5070.05 0 09:11 1.03
7456 JUNCTION 1.60 2.26 5110.17 0 07:52 2.26
417 OUTFALL 0.00 0.00 4980.32 0 00:00 0.00
443 OUTFALL 0.03 0.89 5073.16 0 06:41 0.89
900 OUTFALL 0.00 0.00 4987.00 0 00:00 0.00
901 OUTFALL 0.76 1.23 4975.25 0 08:46 1.23
902 OUTFALL 0.00 0.00 4973.21 0 00:00 0.00
903 OUTFALL 0.00 0.00 4977.40 0 00:00 0.00
904 OUTFALL 0.00 0.00 4973.14 0 00:00 0.00
907 OUTFALL 0.00 0.00 4972.52 0 00:00 0.00
421 OUTFALL 0.00 0.00 4990.00 0 00:00 0.00
2 STORAGE 0.00 0.00 4991.00 0 00:00 0.00
424 STORAGE 1.06 7.47 5017.47 0 07:17 7.47
425 STORAGE 0.75 4.50 4983.50 0 09:56 4.50
426 STORAGE 6.75 8.46 4989.46 0 20:00 8.46
427 STORAGE 2.85 3.84 4992.84 0 12:49 3.84
428 STORAGE 2.45 3.12 5000.12 0 08:31 3.12
430 STORAGE 2.46 4.74 4997.64 0 07:22 4.74
432 STORAGE 4.48 5.12 4999.02 1 08:07 5.12
433 STORAGE 5.50 7.32 5006.32 0 08:29 7.32
437 STORAGE 2.92 3.96 5028.66 0 08:06 3.96
438 STORAGE 4.64 5.00 5032.50 0 07:51 5.00
440 STORAGE 6.50 8.44 5033.44 0 08:21 8.44
441 STORAGE 5.95 8.44 5070.20 0 08:16 8.44
446 STORAGE 1.42 5.91 5075.91 0 09:10 5.91
A1 STORAGE 1.45 4.27 5003.93 0 08:11 4.27
A2 STORAGE 3.17 7.57 5011.26 0 08:37 7.57
D STORAGE 0.68 2.42 5001.42 0 08:44 2.42
E STORAGE 3.76 11.11 5011.11 0 08:32 11.11
F STORAGE 1.13 1.87 4992.87 0 12:08 1.87
G2 STORAGE 3.73 6.90 4996.88 0 08:34 6.90
Storage_18 STORAGE 1.79 5.88 4997.88 0 08:28 5.88
Storage_20_1 STORAGE 5.02 23.40 5006.40 0 08:13 23.40
Storage_20_2 STORAGE 0.14 1.22 5003.22 0 07:28 1.22
Storage_20_3 STORAGE 5.29 6.75 5015.75 0 06:55 6.75
Storeage_19 STORAGE 1.78 4.78 4988.78 0 08:21 4.78
100-YEAR SWMM OUTPUT
*******************
Node Inflow Summary
*******************
-------------------------------------------------------------------------------------------------
Maximum Maximum Lateral Total Flow
Lateral Total Time of Max Inflow Inflow Balance
Inflow Inflow Occurrence Volume Volume Error
Node Type CFS CFS days hr:min 10^6 gal 10^6 gal Percent
-------------------------------------------------------------------------------------------------
7 JUNCTION 250.00 250.00 0 00:00 364 364 0.006
18 JUNCTION 0.00 19.60 0 06:14 0 15.2 5.875
19 JUNCTION 0.00 25.88 0 07:17 0 2.62 -0.247
28 JUNCTION 259.54 259.54 0 06:40 6.6 6.6 -8.610
31 JUNCTION 309.06 309.06 0 06:40 9.07 9.07 -26.163
32 JUNCTION 0.00 171.11 0 07:44 0 47.3 7.747
37 JUNCTION 147.82 147.82 0 06:40 2.25 2.25 -16.728
38 JUNCTION 469.06 469.06 0 06:40 14.4 14.4 -3.329
42 JUNCTION 69.13 69.13 0 06:40 2.43 2.43 -2.327
43 JUNCTION 185.32 185.32 0 06:40 2.65 2.65 -0.011
45 JUNCTION 64.69 64.69 0 06:40 2.36 2.36 -2.467
46 JUNCTION 410.22 410.22 0 06:40 7.93 7.93 -22.017
50 JUNCTION 210.28 210.28 0 06:40 6.92 6.92 -3.681
51 JUNCTION 443.48 443.48 0 06:45 12.2 12.2 -3.417
427.1 JUNCTION 0.00 15.34 0 06:47 0 6.28 0.441
427.2 JUNCTION 0.00 8.58 0 08:44 0 3.26 0.012
725 JUNCTION 139.79 695.92 0 09:17 5.32 83.3 -0.106
726 JUNCTION 225.58 237.46 0 06:50 7.39 57 15.803
729 JUNCTION 999.81 999.81 0 06:40 16.8 47.1 -1.547
730 JUNCTION 0.00 321.92 0 09:09 0 30.8 0.558
819 JUNCTION 0.00 199.96 0 09:07 0 125 -0.003
822.1 JUNCTION 0.00 295.61 0 08:42 0 191 0.155
822.2 JUNCTION 0.00 273.87 0 08:43 0 187 0.032
826 JUNCTION 45.65 49.75 0 06:40 1.56 33.2 1.613
828 JUNCTION 0.00 271.92 0 08:42 0 186 0.034
829 JUNCTION 0.00 704.41 0 09:08 0 78.5 0.667
831 JUNCTION 0.00 269.88 0 08:42 0 185 0.037
833.1 JUNCTION 0.00 253.31 0 07:40 0 184 0.417
833.2 JUNCTION 0.00 407.25 0 07:32 0 215 0.193
834 JUNCTION 213.00 1787.65 0 08:31 6.1 485 -0.185
100-YEAR SWMM OUTPUT
839 JUNCTION 115.30 404.72 0 07:13 1.08 210 0.125
841 JUNCTION 0.00 407.26 0 07:18 0 216 0.307
842 JUNCTION 0.00 1037.70 0 07:33 0 430 0.126
843 JUNCTION 0.00 638.23 0 07:40 0 221 0.008
844 JUNCTION 0.00 391.00 0 07:11 0 209 0.054
845 JUNCTION 0.00 1089.52 0 07:14 0 430 0.474
850 JUNCTION 0.00 664.29 0 07:13 0 408 0.244
855 JUNCTION 0.00 307.32 0 08:44 0 198 0.033
856 JUNCTION 0.00 122.64 0 08:44 0 86.7 0.131
857 JUNCTION 0.00 184.68 0 08:44 0 111 1.055
940 JUNCTION 0.00 1717.13 0 08:49 0 486 0.213
941 JUNCTION 0.00 314.46 0 09:07 0 28.2 -0.114
942 JUNCTION 0.00 1335.00 0 09:00 0 457 0.033
7240 JUNCTION 0.00 3.00 0 06:21 0 3.85 0.773
7244 JUNCTION 310.16 310.16 0 07:22 12.4 12.4 -1.522
7251 JUNCTION 0.00 423.69 0 07:01 0 12.7 1.348
7430 JUNCTION 0.00 28.73 0 07:22 0 2.59 -0.901
7431 JUNCTION 0.00 1376.55 0 09:06 0 469 -0.806
7432 JUNCTION 0.00 26.28 1 08:07 0 22.8 2.255
7435 JUNCTION 415.11 415.11 0 08:39 30.5 30.5 0.623
7436 JUNCTION 1546.86 1546.86 0 08:33 455 455 0.000
7437 JUNCTION 0.00 255.40 0 08:06 0 23.8 1.368
7441 JUNCTION 0.00 5.29 0 08:16 0 5.83 0.293
7446 JUNCTION 0.00 20.95 0 09:10 0 7.92 0.001
7456 JUNCTION 245.10 495.10 0 07:49 37.8 401 0.120
417 OUTFALL 139.52 139.52 0 06:45 2.95 2.95 0.000
443 OUTFALL 0.00 151.67 0 06:41 0 2.65 0.000
900 OUTFALL 0.00 62.07 0 07:28 0 3.43 0.000
901 OUTFALL 0.00 122.62 0 08:46 0 86.6 0.000
902 OUTFALL 0.00 199.96 0 09:07 0 125 0.000
903 OUTFALL 0.00 14.10 0 06:12 0 8.47 0.000
904 OUTFALL 0.00 681.48 0 20:00 0 395 0.000
907 OUTFALL 0.00 478.69 0 09:56 0 83 0.000
421 OUTFALL 62.49 62.49 0 06:40 1.28 1.28 0.000
2 STORAGE 0.00 0.00 0 00:00 0 0 0.000 gal
424 STORAGE 280.13 280.13 0 06:40 2.62 2.62 -0.000
425 STORAGE 0.00 696.50 0 09:20 0 83.4 0.109
426 STORAGE 0.00 1383.20 0 09:26 0 520 11.125
427 STORAGE 117.71 117.71 0 06:40 2.71 8.73 2.173
428 STORAGE 0.00 227.74 0 06:56 0 7.22 12.984
430 STORAGE 231.26 231.26 0 06:40 2.6 2.6 -0.018
432 STORAGE 122.41 176.96 0 08:34 4.29 48.2 15.019
100-YEAR SWMM OUTPUT
433 STORAGE 1299.20 1299.20 0 06:40 14.8 15.9 0.000
437 STORAGE 61.16 369.31 0 07:24 0.893 29.7 18.159
438 STORAGE 0.00 883.20 0 07:32 0 236 0.742
440 STORAGE 848.72 848.72 0 06:40 8.82 9.42 0.000
441 STORAGE 878.27 878.27 0 06:40 9.41 9.41 0.005
446 STORAGE 0.00 402.64 0 06:57 0 10.2 28.236
A1 STORAGE 56.10 62.55 0 06:40 0.809 3.43 1.268
A2 STORAGE 76.95 76.95 0 06:40 1.18 1.18 0.000
D STORAGE 172.20 172.20 0 06:40 3.47 3.47 -0.000
E STORAGE 85.56 85.56 0 06:40 1.23 1.23 0.001
F STORAGE 193.79 193.87 0 06:40 3.28 6.76 0.423
G2 STORAGE 58.72 58.72 0 06:40 0.885 0.969 -0.009
Storage_18 STORAGE 888.12 888.12 0 06:40 11.9 11.9 -21.949
Storage_20_1 STORAGE 862.13 862.13 0 06:40 8.47 8.47 -0.013
Storage_20_2 STORAGE 84.34 132.24 0 06:53 1.3 3.44 0.066
Storage_20_3 STORAGE 267.98 267.98 0 06:40 3.39 3.39 0.001
Storeage_19 STORAGE 603.74 603.74 0 06:40 7.14 7.15 -0.077
**********************
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
---------------------------------------------------------------------
7436 JUNCTION 54.00 0.000 10.000
2 STORAGE 54.00 0.000 6.000
424 STORAGE 54.00 7.466 0.534
430 STORAGE 54.00 4.735 0.265
433 STORAGE 54.00 7.321 0.189
440 STORAGE 54.00 8.443 0.407
441 STORAGE 54.00 8.439 0.261
A2 STORAGE 54.00 7.566 0.934
D STORAGE 10.19 1.170 0.080
E STORAGE 54.00 11.107 1.893
G2 STORAGE 52.69 6.456 0.604
Storage_18 STORAGE 54.00 5.877 94.123
Storage_20_1 STORAGE 54.00 23.401 76.599
100-YEAR SWMM OUTPUT
Storeage_19 STORAGE 54.00 4.782 5.218
*********************
Node Flooding Summary
*********************
Flooding refers to all water that overflows a node, whether it ponds or not.
--------------------------------------------------------------------------
Total Maximum
Maximum Time of Max Flood Ponded
Hours Rate Occurrence Volume Depth
Node Flooded CFS days hr:min 10^6 gal Feet
--------------------------------------------------------------------------
425 0.23 86.75 0 09:56 0.271 0.000
438 46.14 812.68 0 07:51 175.152 0.000
**********************
Storage Volume Summary
**********************
--------------------------------------------------------------------------------------------------
Average Avg Evap Exfil Maximum Max Time of Max Maximum
Volume Pcnt Pcnt Pcnt Volume Pcnt Occurrence Outflow
Storage Unit 1000 ft3 Full Loss Loss 1000 ft3 Full days hr:min CFS
--------------------------------------------------------------------------------------------------
2 0.000 0 0 0 0.000 0 0 00:00 0.00
424 25.034 9 0 0 247.328 88 0 07:17 25.88
425 277.968 10 0 0 2703.127 100 0 09:56 478.69
426 7426.808 63 0 0 10531.339 89 0 20:00 681.48
427 108.796 7 0 0 203.554 13 0 12:49 18.53
428 530.050 30 0 0 716.281 41 0 08:31 37.83
430 83.703 31 0 0 239.656 89 0 07:22 28.73
432 2071.309 30 0 0 2547.471 37 1 08:07 26.28
433 1109.746 52 0 0 2031.739 95 0 08:29 10.00
437 163.674 47 0 0 310.048 90 0 08:06 255.40
438 5424.055 90 0 0 6049.552 100 0 07:51 10.83
440 880.942 67 0 0 1234.612 94 0 08:21 3.00
441 735.908 57 0 0 1226.453 95 0 08:16 5.29
446 61.747 1 0 0 257.608 6 0 09:10 20.95
A1 9.175 8 0 0 61.504 52 0 08:11 20.88
100-YEAR SWMM OUTPUT
A2 36.779 21 0 0 140.759 79 0 08:37 1.94
D 109.399 27 0 0 390.096 97 0 08:44 8.58
E 40.461 22 0 0 147.738 82 0 08:32 2.04
F 296.393 38 0 0 489.777 62 0 12:08 7.70
G2 37.603 27 0 0 115.898 84 0 08:34 1.48
Storage_18 306.655 0 0 0 1396.069 0 0 08:28 19.60
Storage_20_1 218.825 5 0 0 1019.362 23 0 08:13 14.10
Storage_20_2 8.006 3 0 0 73.335 29 0 07:28 62.07
Storage_20_3 147.382 41 0 0 215.804 60 0 06:55 91.59
Storeage_19 187.983 4 0 0 849.923 18 0 08:21 11.70
***********************
Outfall Loading Summary
***********************
-----------------------------------------------------------
Flow Avg Max Total
Freq Flow Flow Volume
Outfall Node Pcnt CFS CFS 10^6 gal
-----------------------------------------------------------
417 5.26 38.57 139.52 2.950
443 23.74 7.66 151.67 2.646
900 88.42 2.66 62.07 3.425
901 97.82 60.90 122.62 86.626
902 97.80 87.61 199.96 124.589
903 41.34 14.09 14.10 8.468
904 88.39 307.20 681.48 394.826
907 88.50 64.51 478.69 83.015
421 5.02 17.58 62.49 1.284
-----------------------------------------------------------
System 59.59 600.78 910.81 707.829
********************
Link Flow Summary
********************
-----------------------------------------------------------------------------
Maximum Time of Max Maximum Max/ Max/
|Flow| Occurrence |Veloc| Full Full
Link Type CFS days hr:min ft/sec Flow Depth
100-YEAR SWMM OUTPUT
-----------------------------------------------------------------------------
18 CONDUIT 19.60 0 07:36 3.51 0.00 0.05
22 CONDUIT 62.07 0 07:28 1.38 0.05 0.30
23 CONDUIT 254.79 0 00:00 5.94 0.11 0.27
25 CHANNEL 696.50 0 09:20 8.94 0.70 0.75
26 CHANNEL 318.11 0 08:18 1.58 0.07 0.89
26.1 CONDUIT 12.71 0 06:49 0.51 0.01 0.28
26.2 CONDUIT 8.57 0 08:51 0.64 0.00 0.12
28 CHANNEL 227.74 0 06:56 11.20 0.04 0.40
29 CHANNEL 661.50 0 06:54 6.01 0.04 0.36
30 CHANNEL 312.01 0 09:19 3.04 0.03 0.44
31 CHANNEL 319.40 0 07:22 4.95 0.05 0.51
32.1 CHANNEL 146.77 0 08:52 1.57 0.06 0.63
32.2 CHANNEL 171.11 0 07:44 2.21 0.03 0.47
34 CHANNEL 1717.13 0 08:49 3.53 0.31 0.82
37 CONDUIT 135.83 0 06:41 1.84 0.01 0.44
38 CHANNEL 456.14 0 06:50 2.19 0.03 0.55
41 CONDUIT 5.28 0 08:26 6.16 0.22 0.32
42 CONDUIT 62.29 0 06:53 1.15 0.01 0.29
43 CONDUIT 151.67 0 06:41 3.45 0.01 0.19
45 CONDUIT 57.95 0 06:51 0.25 0.00 0.46
46 CHANNEL 402.64 0 06:57 9.35 0.06 0.59
50 CHANNEL 189.60 0 07:08 4.17 0.02 0.41
51 CHANNEL 423.69 0 07:01 5.31 0.23 0.64
70 CONDUIT 122.62 0 08:46 4.48 0.02 0.11
71 CONDUIT 295.62 0 08:44 7.12 0.12 0.23
72.1 CONDUIT 273.87 0 08:44 12.07 0.86 0.57
72.2 CONDUIT 271.93 0 08:43 10.28 0.85 0.65
73.1 CONDUIT 269.88 0 08:42 9.63 0.85 0.68
73.2 CONDUIT 235.68 0 08:59 9.41 0.60 0.63
74.1 CONDUIT 240.34 0 07:40 2.97 0.13 0.36
74.2 CONDUIT 407.25 0 07:32 4.62 0.17 0.36
75 CONDUIT 402.42 0 07:18 4.67 0.06 0.31
76 CONDUIT 391.38 0 07:13 5.81 0.09 0.24
77 CONDUIT 992.43 0 07:34 8.99 0.09 0.22
78 CONDUIT 654.95 0 07:23 7.96 0.09 0.34
79 CONDUIT 495.06 0 07:52 6.69 0.25 0.49
153 CONDUIT 25.80 0 07:20 1.26 0.01 0.35
218 CONDUIT 180.36 0 09:07 1.35 0.03 0.23
227 CHANNEL 36.85 1 05:00 0.74 0.01 0.64
229 CHANNEL 687.52 0 09:18 4.68 0.58 0.89
231 CHANNEL 1317.74 0 09:31 5.60 0.04 0.52
100-YEAR SWMM OUTPUT
232 CHANNEL 26.28 1 08:27 1.07 0.00 0.39
234 CHANNEL 1333.70 0 09:14 7.28 0.20 0.52
235 CHANNEL 414.40 0 08:42 4.42 0.02 0.28
236 DUMMY 1546.86 0 08:33
237 CHANNEL 209.77 0 08:31 1.11 0.03 0.60
240 CHANNEL 3.00 0 15:25 0.49 0.00 0.35
242 CHANNEL 638.23 0 07:40 23.79 0.02 0.56
244 CONDUIT 317.48 0 07:24 5.67 0.34 0.68
246 CONDUIT 20.95 0 09:11 8.19 0.53 0.76
251 CHANNEL 378.24 0 07:11 4.24 0.09 0.55
730 CHANNEL 31.76 0 07:37 1.79 0.00 0.23
819 DUMMY 199.96 0 09:07
842D CONDUIT 638.23 0 07:40 6.91 0.10 0.37
842L CONDUIT 391.00 0 07:11 6.01 0.05 0.25
855D CONDUIT 184.68 0 08:44 3.49 0.02 0.33
855L CONDUIT 122.64 0 08:44 4.88 0.01 0.10
940D CHANNEL 314.46 0 09:07 9.65 0.01 0.26
940L CHANNEL 1335.00 0 09:00 5.79 0.17 0.58
941 CHANNEL 315.81 0 09:09 7.25 0.04 0.31
446_OUT ORIFICE 20.95 0 09:10 1.00
D_OUT ORIFICE 8.58 0 08:44 1.00
F_OUT ORIFICE 8.76 0 07:25 0.47
G2_OUT ORIFICE 1.48 0 11:47 1.00
19 WEIR 91.59 0 06:55 0.75
1 DUMMY 14.10 0 06:12
424_OUT DUMMY 25.88 0 07:17
425_OUT DUMMY 478.69 0 09:56
426_OUT DUMMY 681.48 0 20:00
427_OUT DUMMY 7.41 0 12:49
428_OUT DUMMY 37.83 0 08:31
430_OUT DUMMY 28.73 0 07:22
432_OUT DUMMY 26.28 1 08:07
433_OUT DUMMY 10.00 0 06:15
437_OUT DUMMY 255.40 0 08:06
438_Out DUMMY 10.83 0 07:43
440_OUT DUMMY 3.00 0 06:21
441_OUT DUMMY 5.29 0 08:16
9 DUMMY 19.60 0 06:14
A1_OUT DUMMY 20.88 0 08:11
A2_OUT DUMMY 1.94 0 08:37
E_OUT DUMMY 2.04 0 08:32
OL1 DUMMY 11.70 0 01:14
100-YEAR SWMM OUTPUT
***************************
Flow Classification Summary
***************************
-------------------------------------------------------------------------------------
Adjusted ---------- Fraction of Time in Flow Class ----------
/Actual Up Down Sub Sup Up Down Norm Inlet
Conduit Length Dry Dry Dry Crit Crit Crit Crit Ltd Ctrl
-------------------------------------------------------------------------------------
18 1.00 0.03 0.09 0.00 0.00 0.88 0.00 0.00 0.00 0.00
22 1.00 0.11 0.00 0.00 0.00 0.00 0.00 0.89 0.00 0.00
23 1.00 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.00
25 1.00 0.11 0.00 0.00 0.87 0.01 0.00 0.00 0.02 0.00
26 1.00 0.11 0.00 0.00 0.89 0.00 0.00 0.00 0.02 0.00
26.1 1.00 0.11 0.00 0.00 0.88 0.00 0.00 0.00 0.05 0.00
26.2 1.00 0.11 0.00 0.00 0.88 0.00 0.00 0.00 0.88 0.00
28 1.00 0.11 0.00 0.00 0.87 0.02 0.00 0.00 0.86 0.00
29 1.00 0.11 0.00 0.00 0.89 0.00 0.00 0.00 0.87 0.00
30 1.00 0.12 0.00 0.00 0.88 0.00 0.00 0.00 0.34 0.00
31 1.00 0.11 0.00 0.00 0.89 0.00 0.00 0.00 0.86 0.00
32.1 1.00 0.01 0.00 0.00 0.99 0.00 0.00 0.00 0.06 0.00
32.2 1.00 0.01 0.00 0.00 0.99 0.00 0.00 0.00 0.96 0.00
34 1.00 0.11 0.00 0.00 0.89 0.00 0.00 0.00 0.48 0.00
37 1.00 0.11 0.00 0.00 0.89 0.00 0.00 0.00 0.88 0.00
38 1.00 0.00 0.11 0.00 0.89 0.00 0.00 0.00 0.89 0.00
41 1.00 0.12 0.00 0.00 0.00 0.00 0.00 0.88 0.00 0.00
42 1.00 0.00 0.11 0.00 0.89 0.00 0.00 0.00 0.89 0.00
43 1.00 0.11 0.00 0.00 0.89 0.00 0.00 0.00 0.00 0.00
45 1.00 0.00 0.11 0.00 0.89 0.00 0.00 0.00 0.89 0.00
46 1.00 0.11 0.00 0.00 0.88 0.01 0.00 0.00 0.87 0.00
50 1.00 0.00 0.11 0.00 0.88 0.00 0.00 0.00 0.86 0.00
51 1.00 0.11 0.00 0.00 0.89 0.00 0.00 0.00 0.83 0.00
70 1.00 0.02 0.00 0.00 0.98 0.00 0.00 0.00 0.00 0.00
71 1.00 0.01 0.00 0.00 0.99 0.00 0.00 0.00 0.00 0.00
72.1 1.00 0.01 0.00 0.00 0.01 0.98 0.00 0.00 0.00 0.00
72.2 1.00 0.01 0.00 0.00 0.99 0.00 0.00 0.00 0.00 0.00
73.1 1.00 0.01 0.00 0.00 0.99 0.00 0.00 0.00 0.02 0.00
73.2 1.00 0.01 0.00 0.00 0.88 0.11 0.00 0.00 0.00 0.00
74.1 1.00 0.01 0.00 0.00 0.99 0.00 0.00 0.00 0.98 0.00
74.2 1.00 0.01 0.00 0.00 0.99 0.00 0.00 0.00 0.01 0.00
100-YEAR SWMM OUTPUT
75 1.00 0.00 0.00 0.00 0.99 0.00 0.00 0.00 0.99 0.00
76 1.00 0.00 0.00 0.00 1.00 0.00 0.00 0.00 0.00 0.00
77 1.00 0.00 0.00 0.00 1.00 0.00 0.00 0.00 0.00 0.00
78 1.00 0.00 0.00 0.00 0.99 0.01 0.00 0.00 0.99 0.00
79 1.00 0.00 0.00 0.00 1.00 0.00 0.00 0.00 1.00 0.00
153 1.00 0.11 0.00 0.00 0.89 0.00 0.00 0.00 0.88 0.00
218 1.00 0.02 0.00 0.00 0.98 0.00 0.00 0.00 0.00 0.00
227 1.00 0.11 0.00 0.00 0.89 0.00 0.00 0.00 0.08 0.00
229 1.00 0.11 0.00 0.00 0.88 0.00 0.00 0.00 0.88 0.00
231 1.00 0.11 0.00 0.00 0.88 0.01 0.00 0.00 0.84 0.00
232 1.00 0.11 0.25 0.00 0.64 0.00 0.00 0.00 0.64 0.00
234 1.00 0.11 0.00 0.00 0.88 0.00 0.00 0.00 0.34 0.00
235 1.00 0.11 0.01 0.00 0.88 0.00 0.00 0.00 0.88 0.00
237 1.00 0.11 0.00 0.00 0.89 0.00 0.00 0.00 0.89 0.00
240 1.00 0.01 0.10 0.00 0.89 0.00 0.00 0.00 0.89 0.00
242 1.00 0.00 0.00 0.00 0.91 0.09 0.00 0.00 0.95 0.00
244 1.00 0.11 0.00 0.00 0.88 0.00 0.00 0.00 0.87 0.00
246 1.00 0.00 0.12 0.00 0.68 0.21 0.00 0.00 0.88 0.00
251 1.00 0.00 0.11 0.00 0.88 0.00 0.00 0.00 0.88 0.00
730 1.00 0.11 0.00 0.00 0.89 0.00 0.00 0.00 0.38 0.00
842D 1.00 0.00 0.00 0.00 1.00 0.00 0.00 0.00 0.98 0.00
842L 1.00 0.00 0.00 0.00 1.00 0.00 0.00 0.00 0.97 0.00
855D 1.00 0.02 0.00 0.00 0.98 0.00 0.00 0.00 0.97 0.00
855L 1.00 0.02 0.00 0.00 0.98 0.00 0.00 0.00 0.98 0.00
940D 1.00 0.15 0.49 0.00 0.08 0.29 0.00 0.00 0.85 0.00
940L 1.00 0.11 0.00 0.00 0.88 0.00 0.00 0.00 0.87 0.00
941 1.00 0.12 0.03 0.00 0.84 0.01 0.00 0.00 0.51 0.00
*************************
Conduit Surcharge Summary
*************************
----------------------------------------------------------------------------
Hours Hours
--------- Hours Full -------- Above Full Capacity
Conduit Both Ends Upstream Dnstream Normal Flow Limited
----------------------------------------------------------------------------
26 0.01 0.01 43.16 0.01 0.01
229 0.01 0.01 0.48 0.01 0.01
246 0.01 0.01 47.75 0.01 0.01
100-YEAR SWMM OUTPUT
Rating Curve Pond_A1_Out
Head (ft)
76543210Outflow (CFS)65
60
55
50
45
40
35
30
25
20
15
10
5
0
Model 2 of 3
SWMM 5.1 Page 1
Rating Curve Pond_A2_Out
Head (ft)
9876543210Outflow (CFS)18
16
14
12
10
8
6
4
2
0
Model 2 of 3
SWMM 5.1 Page 1
Rating Curve Pond_E_Out
Head (ft)
131211109876543210Outflow (CFS)60
55
50
45
40
35
30
25
20
15
10
5
0
Model 2 of 3
SWMM 5.1 Page 1
Storage Curve A1__Storage
Depth (ft)6
5.5
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
Model 2 of 3
SWMM 5.1 Page 1
Storage Curve A2__Storage
Depth (ft)8
7
6
5
4
3
2
1
0
Model 2 of 3
SWMM 5.1 Page 1
Storage Curve E_Storage
Depth (ft)13
12
11
10
9
8
7
6
5
4
3
2
1
0
Model 2 of 3
SWMM 5.1 Page 1
Node A1 Depth (ft)
Elapsed Time (hours)
6050403020100Depth (ft)2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Model 2 of 3
SWMM 5.1 Page 1
Node A2 Depth (ft)
Elapsed Time (hours)
6050403020100Depth (ft)3.0
2.5
2.0
1.5
1.0
0.5
0.0
Model 2 of 3
SWMM 5.1 Page 1
Node E Depth (ft)
Elapsed Time (hours)
6050403020100Depth (ft)2.5
2.0
1.5
1.0
0.5
0.0
Model 2 of 3
SWMM 5.1 Page 1
Node A1 Depth (ft)
Elapsed Time (hours)
160140120100806040200Depth (ft)4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Model 2 of 3
SWMM 5.1 Page 1
Node A2 Depth (ft)
Elapsed Time (hours)
80706050403020100Depth (ft)8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
Model 2 of 3
SWMM 5.1 Page 1
Node E Depth (ft)
Elapsed Time (hours)
80706050403020100Depth (ft)12.0
10.0
8.0
6.0
4.0
2.0
0.0
Model 2 of 3
SWMM 5.1 Page 1
PROJECT INFORMATION
PROJECT NAME:
PROJECT #:
POND NAME:
DATE:
Required Water Quality Volume:
Detention Sizing Method: WQCV
NRCS Hydrologic Soil Group: C & D
*Figure 3-1, UDFCD (V.3), Chapter 3, Page 3-5
*Equations 12-1, 12-2, 12-3, UDFCD (V.2), Chapter 12, Page 12-4
Where:
WQCV = Water Quality Capture Volume (Watershed Inches)
a = Constant Dependent on Drain Time (Typically a=1.0 40-Hr Drain Time)
i = Percent Imperviousness
i = 61.0%
WQCV = 0.240 (watershed inches)
*Equation 3-3, UDFCD (V.3), Chapter 3, Page 3-6
Where:
WQCV = Water Quality Capture Volume (Watershed Inches)
Area = Contributing Watershed Area (Acres)
Area = 10.31 (acres)
Required Storage = 0.2470 (ac-ft)
Montava Phase G
19.1354
Pond A1
12/14/2021
12/14/2021 10:38 AM
WQCV
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\PONDS\Pond A1\WQCV_Pond A1.xlsx
PROJECT INFORMATION
PROJECT NAME:
PROJECT #:
POND NAME:
DATE:
Required Water Quality Volume:
Detention Sizing Method: WQCV
NRCS Hydrologic Soil Group: C & D
*Figure 3-1, UDFCD (V.3), Chapter 3, Page 3-5
*Equations 12-1, 12-2, 12-3, UDFCD (V.2), Chapter 12, Page 12-4
Where:
WQCV = Water Quality Capture Volume (Watershed Inches)
a = Constant Dependent on Drain Time (Typically a=1.0 40-Hr Drain Time)
i = Percent Imperviousness
i = 68.0%
WQCV = 0.266 (watershed inches)
*Equation 3-3, UDFCD (V.3), Chapter 3, Page 3-6
Where:
WQCV = Water Quality Capture Volume (Watershed Inches)
Area = Contributing Watershed Area (Acres)
Area = 14.48 (acres)
Required Storage = 0.3856 (ac-ft)
Montava Phase G
19.1354
Pond A2
12/14/2021
12/14/2021 10:38 AM
WQCV
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\PONDS\Pond A2\WQCV_Pond A2.xlsx
PROJECT INFORMATION
PROJECT NAME:
PROJECT #:
POND NAME:
DATE:
Required Water Quality Volume:
Detention Sizing Method: WQCV
NRCS Hydrologic Soil Group: C & D
*Figure 3-1, UDFCD (V.3), Chapter 3, Page 3-5
*Equations 12-1, 12-2, 12-3, UDFCD (V.2), Chapter 12, Page 12-4
Where:
WQCV = Water Quality Capture Volume (Watershed Inches)
a = Constant Dependent on Drain Time (Typically a=1.0 40-Hr Drain Time)
i = Percent Imperviousness
i = 70.0%
WQCV = 0.275 (watershed inches)
*Equation 3-3, UDFCD (V.3), Chapter 3, Page 3-6
Where:
WQCV = Water Quality Capture Volume (Watershed Inches)
Area = Contributing Watershed Area (Acres)
Area = 14.80 (acres)
Required Storage = 0.4070 (ac-ft)
Montava P1A
19.1354
Pond E
12/14/2021
Required Storage X1.2
12/14/2021 10:42 AM
WQCV
G:\LOVATO\19.1354-Montava Phase 1a\ENG\DRAINAGE\EXCEL\PONDS\Pond E\WQCV_Pond E.xlsx
Montava – Phase G PDP
December 14, 2021
D-LID Calculations
BASIN TO LID FEATURE?
AREA % TO
TOTAL SITE BASIN TO LID FEATURE?
AREA % TO TOTAL
SITE BASIN TO LID FEATURE?
AREA % TO
TOTAL SITE
2.1 YES 0.4%3.1 NO 2.2%4.1 YES 2.2%
2.2 YES 0.4%3.2 NO 0.8%4.2 YES 0.6%
2.3 YES 0.4%3.3 NO 2.2%4.3 YES 0.3%
2.4 YES 0.8%3.4 NO 1.0%4.4 YES 2.6%
2.5 YES 0.6%3.5 NO 3.7%4.5 YES 2.8%
2.6 YES 2.7% 3.6 YES 1.2% 4.6 YES 0.3%
2.7 YES 0.9% 3.7 YES 0.5%4.8 NO 1.0%
2.8 YES 2.6% 3.8 YES 1.2%4.9 NO 1.1%
2.9 YES 2.2% 3.9 YES 2.5% 4.10 YES 1.6%
2.10 NO 1.3%3.10 YES 0.6% 4.11 YES 1.6%
2.11 YES 0.3%3.11 NO 0.7%4.12 YES 1.6%
2.12 YES 0.3% 3.12 YES 0.4% 4.13 YES 2.1%
2.13 YES 1.0% 3.13 YES 2.6% 4.14 YES 2.2%
2.14 YES 1.4% 3.14 YES 0.5%
2.15 YES 0.5% 3.15 YES 0.4%
2.16 YES 0.3%3.16 NO 3.1%36.6
2.17 YES 0.8% 3.17 YES 0.4%30.3
2.18 YES 1.0% 3.18 YES 0.6%82.8%
2.19 YES 0.3% 3.19 YES 0.7%
2.20 YES 0.7% 3.20 YES 1.9%
2.21 YES 1.5% 3.21 YES 1.6%
2.22 YES 0.3% 3.22 YES 1.4%
2.23 YES 2.5% 3.23 YES 0.3%
2.24 YES 1.7% 3.24 YES 1.3%
2.25 YES 0.6% 3.25 YES 0.7%
2.26 YES 0.6% 3.26 YES 1.3%
2.27 YES 0.3% 3.27 YES 0.6%
2.28 YES 1.3% 3.28 YES 0.3%
2.29 YES 2.9% 3.29 YES 1.1%
2.30 YES 4.0% 3.30 YES 1.1%
2.31 YES 0.6% 3.31 YES 0.3%
2.32 YES 3.6% 3.32 YES 1.5%
2.33 YES 2.0% 3.33 YES 0.5%
3.34 YES 0.3%
3.35 YES 0.2%
TOTAL APPLICABLE LID
TREATMENT AREA*
LID TREATED AREA
LID TREATED PRECENTAGE
*BASIN 4.7 HAS NOT BEEN INCLUDED IN
THE OVERALL APPLICABLE LID TREATMENT
AREAS AND WILL BE REQUIRED TO PROVIDE
ON-SITE LID TREATMENT UPON
Montava – Phase G PDP
December 14, 2021
D-Drainage Plans
PHASE G DRAINAGE PLAND1----MARTIN/MARTIN
C O N S U L T I N G E N G I N E E R S
12499 WEST COLFAX AVENUE, LAKEWOOD, COLORADO 80215
303.431.6100 MARTINMARTIN.COM
NOT FOR CONSTRUCTION
MONTAVA
PHASE G
UTILITY PLANS1
1MARTIN/MARTIN
C O N S U L T I N G E N G I N E E R S
12499 WEST COLFAX AVENUE, LAKEWOOD, COLORADO 80215
303.431.6100 MARTINMARTIN.COM
NOT FOR CONSTRUCTION
MONTAVA
PHASE G
UTILITY PLANS
PHASE G DRAINAGE PLAND2----