HomeMy WebLinkAboutNORTH COLLEGE DRIVE THRU - PDP - PDP160014 - REPORTS - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT
NORTH COLLEGE DRIVE-THROUGH
Fort Collins, Colorado
July 27th, 2016
Chad Prepared A. Hirshfield for:
Denver, PO Colorado Box 102291 80250
Prepared by:
301 Fort Collins, North Howes Colorado Street, 80521 Suite 100
Phone: www.northernengineering.970.221.4158 com Fax: 970.221.4159
Project Number: 1249-001
This Drainage Report is consciously provided as a PDF.
Please When a consider hard copy the is environment absolutely necessary, before printing we recommend this document double-in its sided entirety. printing.
April 13, 2016
City of Fort Collins
Stormwater 700 Wood Street Utility
Fort Collins, Colorado 80521
RE: North Final Drainage College Drive Report Through for
Dear Staff:
Northern Engineering is pleased to submit this Preliminary Drainage and Erosion Control Report for
your College review. Drive This Through. report Comments accompanies from the the Conceptual Preliminary Review Development submittal Review for the Letter proposed dated North
September comprehensive 14, response 2015 have to been comments addressed. letter on Written file with responses Current thereto Planning. can be found in the
This report has been prepared in accordance to Fort Collins Stormwater Criteria Manual (FCSCM),
and Through serves project. to document We understand the stormwater that review impacts by the associated City is to with assure the proposed general compliance North College with Drive
standardized criteria contained in the FCSCM.
If you should have any questions as you review this report, please feel free to contact us.
Sincerely,
NORTHERN ENGINEERING SERVICES, INC.
Nicholas W. Haws, PE Blaine Mathisen
Project Manager Project Engineer
North College Drive Through
Final Drainage Report
TABLE OF CONTENTS
I. A. Location GENERAL ......LOCATION ....................AND .........DESCRIPTION ............................................................................................................................................................................
. 1 1
B. Description of Property ..................................................................................................................... 2
C. Floodplain.......................................................................................................................................... 3
II. A. Major DRAINAGE Basin Description BASINS AND .......SUB-.........BASINS ..........................................................................................................................................................................
. 5 5
B. Sub-Basin Description ....................................................................................................................... 5
III. A. Regulations.DRAINAGE ..DESIGN ...............CRITERIA ........................................................................................................................................................................................................
. 5 5
B. Four Step Process .............................................................................................................................. 5
C. Development Criteria Reference and Constraints ............................................................................ 6
D. Hydrological Criteria ......................................................................................................................... 6
E. Hydraulic Criteria .............................................................................................................................. 7
F. Floodplain Regulations Compliance .................................................................................................. 7
G. Modifications of Criteria ................................................................................................................... 7
IV. A. General DRAINAGE Concept FACILITY ...........DESIGN .......................................................................................................................................................................................................
. 7 7
B. Specific Details .................................................................................................................................. 8
V. A. Compliance CONCLUSIONS with .Standards ...............................................................................................................................................................................................................
.. 10 10
B. Drainage Concept ............................................................................................................................ 10
References ....................................................................................................................... 11
APPENDICES: APPENDIX A – Hydrologic Computations
APPENDIX B B.1 – – Hydraulic Storm Sewers Computations (For Future Use)
B.B.3 2 – – Detention Inlets (For Facilities Future Use) (For Future Use)
APPENDIX APPENDIX C D – – Water Erosion Quality Control Design Report Computations
North College Drive Through
Final Drainage Report
LIST Figure OF 1 – TABLES Aerial Photograph AND FIGURES: ................................................................................................ 2
Figure Figure 2– 3 – Proposed Existing FEMA Site Plan Floodplains ...................................................................................................................................................................................
. 3 4
Figure 4 – Existing City Floodplains ....................................................................................... 4
MAP C4.00 POCKET: - Drainage Exhibit
C4.01 – Historic Drainage Exhibit
North College Drive Through
Final Drainage Report 1
I. GENERAL LOCATION AND DESCRIPTION
A. Location
1. Vicinity Map
2. North Township County College of Larimer, 7 North, Drive State Range Through of 69 Colorado. project West of is the located 6th Principal in the northeast Meridian, quarter City of
of Fort Section Collins, 2,
3. The and North project College site is located Mobile Home west of Park North at College the address Avenue of 1603-between 1605 Schroders N. College P.U.Ave. D
4. Currently existing project the existing site has lot 1.does 0% not imperviousness, have any stormwater as it has or remained water quality undeveloped. facilities. The The
existing Avenue. site sheet flows from west to east and north to south towards North College
5. The north project by a car is currently wash, east bordered by North to College the west Avenue. and south by single family residences,
North College Drive Through
Final Drainage Report 2
B. Description of Property
1. North College Drive Through is approximately 0.69 net acres.
Figure 1 – Aerial Photograph
2. North no off-College site drainage Drive entering Through the consists existing of two property. separate Runoff lots generated (Lot 1 and from Lot 2)the . There project is
drains southeast towards North College Avenue.
3. According Conservation to the Service United (NRCS) States Soil Department Survey, 100 of Agriculture percent of the (USDA) site consists Natural Resources of Nunn
clay by Earth loam, Engineering which falls Consultants, into Hydrologic LLC, Soil dated Groups March C. 22, A site 2016 specific notes report that the prepared project
site lean consists clay to clayey of 2 to sand 4 feet with of apparent gravel materials. fill material Underlying which generally the apparent consisted surficial of sandy fill
materials, sand and gravel was lean materials. clay with Groundwater varying amount was observed of sand underlain during the by time silty/of poorly the borings graded
to be approximately 5 to 6 feet below existing site grades.
4. The The proposed proposed development project will include will include one commercial the clearing building, of existing exterior vegetation parking and lots trees. and
associated composed of drive permeable aisle and pavers sidewalks. and paving. The exterior The section parking of lot drive is planned constructed to be of
permeable facility. Additional pavers will water act quality as a portion will be of provided the project’s in the water form quality of two and rain detention gardens and
surrounding stormwater criteria. green space. Underground detention will be provided to meet Fort Collins
North College Drive Through
Final Drainage Report 3
Figure 2– Proposed Site Plan
5. No irrigation facilities or major drainageways are within the property limits.
6. The proposed project use site is is permitted within the within Service the Commercial zone district. District (C-S) Zoning District. The
C. Floodplain
1. The subject property is not located in a FEMA or City regulatory floodplain.
2. The nearest FEMA FEMA Panel delineated 08069C0977G regulatory illustrates floodplain. the It proximity is noted of that the the project vertical site datum to the
utilized for site survey work is the City of Fort Collins Benchmark #1-10
Elevation = 4987.25 (NAVD 88)
North College Drive Through
Final Drainage Report 4
Figure 3 – Existing FEMA Floodplains
Figure 4 – Existing City Floodplains
North College Drive Through
Final Drainage Report 5
II.
DRAINAGE BASINS AND SUB-BASINS
A. Major Basin Description
1. North extends College from near Drive the Through Wyoming is located border within to the Poudre the Dry River Creek near Master Mulberry Basin, and which
Timberline.
B. Sub-Basin Description
1. The routed property via overland historically flow across drains east the existing towards lot. North College Avenue. Stormwater is
2. Basin the 2-year EX1 storm is historically and 1.30 discharged cfs for the directly 100-year into event)North . College Avenue (0.29 cfs for
3. A Section more detailed IV.A.4., description below. of the projects proposed drainage patterns follows in
4. No drainage is routed onto the property from the surrounding properties.
A Map full-Pocket size copy at the of the end Historic of this report. and Proposed Drainage Exhibit can be found in the
III.
DRAINAGE DESIGN CRITERIA
A. Regulations
There Drive Through are no optional project. provisions outside of the FCSCM proposed with the North College
B. Four Step Process
The Through overall project stormwater utilizes management the “Four Step strategy Process” employed to minimize with adverse the North impacts College of Drive
urbanization development on has receiving incorporated waters. each The step. following is a description of how the proposed
Step 1 – Employ Runoff Reduction Practices
Several reduction techniques of runoff peaks, have been volumes, utilized and with pollutant the proposed loads as development the site is developed to facilitate from the the
current use by implementing multiple Low-Impact Development (LID) strategies including:
Providing site to reduce vegetated the overall open impervious areas along area the north, and to south, minimize east, directly and west connected portion of the
impervious areas (MDCIA).
Routing or through flows, bio-media to the extent within feasible, the rain gardens. through drain rock both within the paver section,
Providing concentration permeable promote paver infiltration areas with and underground provide water detention quality. area to increase time of
Routing biological runoff uptake, from and the evapotranspiration. proposed roofs into an isolator row to promote infiltration,
North College Drive Through
Final Drainage Report 6
Step Slow 2 Release – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with
The BMPs efforts required taken for in water Step quality. 1 will facilitate Stormwater the reduction generated of from runoff the and southern provide portion the necessary of the
project the roof site is routed will be directly routed into through isolator one rows of the located two rain in garden. the underground Stormwater detention generated section from
surrounding the parking area the detention will be routed chambers. via overland Stormwater flow across generated permeable from the pavers western and portion enter the of
southern parking area underground will be routed detention. via overland Stormwater flow across generated permeable from the pavers. northern portion of the
Step 3 – Stabilize Drainageways
As site. stated While in this Section step I.may B.5, not above, seem there applicable are no to major North drainageways College Drive in Through, or near the the subject
proposed site selection project has indirectly a positive helps effect achieve on stream stabilized stabilization. drainageways By repurposing nonetheless. an undeveloped, Once again,
under-likelihood utilized of bed site and with bank no existing erosion stormwater is greatly reduced. infrastructure, Furthermore, combined this with project LID, will the pay
one-both time of which stormwater help achieve development Citywide fees, drainageway as well as stability. ongoing monthly stormwater utility fees,
Step 4 – Implement Site Specific and Other Source Control BMPs.
The and parking North College area, all Drive of which Through will project require includes the need a for new site building specific with source an associated controls drive
including:
A localized trash enclosure at the rear of the building for the disposal of waste.
C. Development Criteria Reference and Constraints
1. There are no known drainage studies for the existing properties.
2. There effect on are the no North known College drainage Drive studies Through for any project. adjacent properties that will have any
3. The surrounded subject by property currently is essentially developed an properties. "in-fill" development As such, several project constraints as the property have been is
identified system including: during the course of this analysis that will impact the proposed drainage
Existing maintained. elevations along the north, south, east, and west property lines will be
Overall drainage patterns of the existing site will be maintained.
D. Hydrological Criteria
1. The Figure City RA-of 16 Fort of Collins the FCSCM, Rainfall serve Intensity-as the Duration-source for Frequency all hydrologic Curves, computations as depicted in
associated utilized for with Rational this Method development. runoff calculations. Tabulated data contained in Table RA-7 has been
2. The coefficients Rational contained Method has in Tables been employed RO-11 and to RO-compute 12 of stormwater the FCSCM. runoff utilizing
3. The procedure Rational has Formula-been utilized based for Modified detention Federal storage Aviation calculations. Administration (FAA)
North College Drive Through
Final Drainage Report 7
4. Two The first separate event design analyzed storms is the have “Minor,been ” utilized or “Initial” to address Storm, which distinct has drainage a 2-year scenarios.
recurrence 100-year recurrence interval. The interval. second event considered is the “Major Storm,” which has a
5. No that other are not assumptions referenced or by calculation current City methods of Fort Collins have been criteria. used with this development
E. Hydraulic Criteria
1. As The previously majority of noted, the site the drains subject stormwater property historically via overland drains flow. into North College Avenue.
2. All designed drainage in accordance facilities proposed with criteria with the outlined North in College the FCSCM Drive and/Through or the project Urban are
Drainage Manual. and Flood Control District’s (UDFCD) Urban Storm Drainage Criteria
3. As regulatory stated in floodplain. Section I.C.1, above, the subject property is not located within any
4. The drainageways. North College Drive Through project does not propose to modify any natural
F. Floodplain Regulations Compliance
1. As City previously floodplain, mentioned, and thus are all structures not subject are to located any floodplain outside regulations. of any FEMA 100-year or
G. Modifications of Criteria
1. The modification proposed at North this time. College Drive Through development is not requesting any
IV. DRAINAGE FACILITY DESIGN
A. General Concept
1. The existing main drainage objectives patterns of the and North ensure College no adverse Drive Through impacts drainage to any adjacent design is properties. to maintain
2. As property. previously mentioned, there are no off-site flows draining onto the existing
3. A Contents list of tables at the and front figures of the used document. within this The report tables can and be figures found are in the located Table within of the
sections to which the content best applies.
4. The designated North College as Basins Drive N, Through S, and OS. project The is drainage composed patterns of three for major each major drainage basin basins, are
further described below.
Basin N
Basin building N is and further consists subdivided of permeable into two pavers, (2) sub-asphalt, basins. and N1 landscape is located surfacing. north of the
Stormwater generated from this basin is routed via overland and gutter flow and
North College Drive Through
Final Drainage Report 8
crosses sub-basin over N1 permeable is collected pavers via curb to reduce inlet and runoff discharged and provide into Underground water quality. Pond Runoff N. from
Sub-this sub-basin basin N2 is is composed routed internal entirely to the of the building building through roof. pipe Stormwater flow and generated discharged from
directly into an isolator row and then into Underground Pond N.
Basin S
Basin the parking S is further area located subdivided west into of the two building (2) sub-as basins. well as Sub-some basin landscape S1 is composed surfacing, of but
predominantly overland and gutter hardscape. flow across Stormwater permeable generated pavers from and is this eventually basin is conveyed routed via through
a composed curb inlet of routing the area the located runoff directly south of into the Underground building and consists Pond S. of Sub-landscape basin S2 is
surfacing is routed via along overland with some and gutter hardscape flow surfaces. and is collected Stormwater in a rain generated garden (from Rain this Garden basin 1)
via Underground curb cuts. Pond Any flow S. above the water quality event is routed via pipes to
Basin OS
Basin OS is further subdivided into two (2) sub-basins, designated as Basins OS1 and
OS2. and southern Sub-basin property OS1 is lines composed and consists primarily of landscape of the area surfacing. located all Stormwater along the western
generated into the adjacent from this property sub-basin of North is routed College via Mobile overland Home flow Park and discharges and North undetained College
Avenue. east of the Sub-building. basin OS2 Stormwater is composed generated of a small from portion this sub-of basin landscaping is routed and via sidewalk overland
flow and discharges undetained into North College Avenue.
A this full-report. size copy of the Drainage Exhibit can be found in the Map Pocket at the end of
B. Specific Details
1. The quality main present drainage and problem lack of stormwater associated infrastructure with this project within site the is the existing deficiency site. of water
Currently Avenue, adjacent the entire sites, site or drains pools overland in a central and location discharges within directly the project into North site. College The
proposed devices: site will mitigate these issues by instituting the following water quality
All routed of the into runoff an isolator generated row from within the Underground proposed building Detention roof Pond (Basin N. N2) will be
The (Basin runoff N1 and generated S1) will from be the routed majority through of the a permeable proposed paver drive aisle system. and parking
Basins S2 and S3 will be routed to rain gardens and through bio-media
2. The calculating release the rate 2-for year the peak undeveloped runoff rate land for (the pre-entire development) project area was and established excluding by all
portions The overall of the 2-year proposed peak runoff project rate that was release calculated undetained at 0.29 (Sub-cfs, basins resulting OS1 in and a OS2)
North College Drive Through
Final Drainage Report 9
maximum being detained)release . This rate release of 0.25 rate cfs was from utilized Basin N in and the FAA S (reduction procedure caused detention by runoff storage not
computations (Refer to Appendix B for these calculations).
3. Detention Pond Calculations
Runoff release rates rate from for the the ponds historic described 2-year event below (0.were 25 cfs)established . as a portion of the max
Underground Pond N
The for Underground FAA method Pond was used N, based to size on the the underground characteristics ponds of Basin for detention. N and an Calculations adjusted
release Detention rate will of be 0.11 provided cfs, indicate by 170 a Stormtech required detention SC-160 volume chambers, of 2,which 699 cu. has ft. an
installed for Basin volume N1. Basin of 2715 N2 (the cu. roof) ft. Water will have quality the will roof be leaders provided tie directly via permeable into an pavers
isolator geotextile row membrane within the to underground reduce sediment system. migration. The isolator The isolator row will row be wrapped and will be with a
released over 12 hours.
Underground Pond S
Calculations release rate of for 0.Pond 14 cfs, S, indicate based on a the detention characteristics volume of of 3,Basin 577 S cu. and ft. an Underground adjusted
Pond storage S volume is utilizing of 3,116 596 StormTech cu. ft. SC-310 chambers which holds an installed
4. Water Quality Results
Basin N
Basin from the N has building water tie quality directly provided into isolator via permeable rows within pavers the underground and having the chambers. roof leaders
Following Basin N1. UDFCD A 10-inch-standards, deep permeable a required section WQCV with of 119 an installed cu. ft must storage be provided capacity for of
647 a WQCV cu. ft of which 72 cu. will ft. provide which will adequate be treated water by quality two isolator for Basin rows N1. wrapped Basin with N2 requires a
geotextile with an assumed membrane porosity to reduce of 0% sediment to accommodate migration. for In sediment order to achieve build up, 72 a cu. total ft. of 11
SC-configuration 160 chambers and size, are required a total of to 12 achieve SC-160 this chambers volume. will However, be dedicated due to chamber to isolator
rows bringing the installed volume of isolator chambers to 82.2 cu. ft.
Basin S
Basin WQCV S of has 161 two cu. separate ft, dictated LID by water UDFCD, quality but amenities. a proposed Sub-1,basin 859 sq. S1 ft has of permeable a required
pavers has a rain with garden a 10-inch-(Rain depth Garden will 1) provide with a 418 required cu. ft WQCV of water of 91.quality. 5 cu. Sub-ft. However, basin S2
the provide constructed 701 cu. volume ft of water of Rain quality. Garden Following 1 with Fort a maximum Collins LID water standards, depth of 25% 12” of will new
paved areas are pervious and 100% is being treated by LID.
5. To permeable minimize pavers the potential cannot infiltrate for increased fast enough, flow to leave curb inlets the site have in the been event provided the to
capture have a sumped and direct bottom excess to runoff capture into sediment the underground and prevent detention the vault vaults. or surrounding All inlets will
North College Drive Through
Final Drainage Report 10
drainage event will rock be routed from siltation. through an Additionally, isolator row all to runoff collect generated any additional from the sedimentation. water quality
6. Rain the case Garden that 1 the was overflow designed grate to overtop gets clogged. the pond In the along case its that southern the overflow edge in
grate the rain should garden. clog However, an additional if Raingarden storage (609 1 was cu. to ft) overtop, has been the provided stormwater within
from Basin Sub-OS1 basin it will S2 split would flow flow west into and Sub-east Basin along OS1. the south Once the property runoff line. is in Flow Sub-
headed will discharge east will into enter the North mobile College home park. Avenue and the remaining western flow
In backwatering the case that should the curb occur, inlet stormwater within Sub-would basin overtop N1 should from clog Sub-or basin N1 into
North case that College the curb Avenue inlet towards within Sub-the northeast basin S1 corner should of clog the or project backwatering site. In the
should where additional occur, stormwater storage has would been overtop provided. from However, Sub-basin in S1 the into event Sub-that basin the S2
inlet into Sub-is clogged basin OS1. and/or From Underground Sub-Basins Pond OS1 S is the full excess the excess runoff runoff will flow will flow
southwest North College until Mobile it crosses Home the Park. property line and enters the adjacent lot of the
V. CONCLUSIONS
A. Compliance with Standards
1. The with drainage the City of design Fort Collins’ proposed Stormwater with the North Criteria College Manual. Drive Through project complies
2. The with drainage the City of design Fort Collins’ proposed Master with the Drainage North Plan College for Drive the Dry Through Creek Basin. project complies
3. There development. are no regulatory floodplains associated with the North College Drive Through
4. The College drainage Drive plan Through and development stormwater management are compliant measures with all applicable proposed with State the and North
Federal regulations governing stormwater discharge.
B. Drainage Concept
1. The associated drainage with design its stormwater proposed with runoff. this North project College will effectively Drive Through limit potential will detain damage for the
pervious during the area developed converted 100-to year impervious storm. areas by releasing at the 2-year historic rate
2.
The Drainage proposed Plan North recommendations College Drive for Through the Dry development Creek major will drainage not impact basin. the Master
North College Drive Through
Final Drainage Report 11
References
1. City November of Fort 5, Collins 2009, Landscape BHA Design, Design Inc. Guidelines with City of for Fort Stormwater Collins Utility and Detention Services. Facilities,
2. Fort 174, Collins 2011, Stormwater and referenced Criteria in Section Manual, 26-City 500 of (Fort c) of Collins, the City Colorado, of Fort Collins as adopted Municipal by Ordinance
Code. No.
3. Larimer Reenacted, County Effective Urban October Area Street 1, 2002, Standards, Repealed Adopted and Reenacted, January 2, Effective 2001, Repealed April 1, 2007. and
4. Soils Service, Resource United Report States for Department Larimer County of Agriculture. Area, Colorado, Natural Resources Conservation
5. Urban District, Storm Wright-Drainage McLaughlin Criteria Engineers, Manual, Denver, Volumes Colorado, 1-3, Urban Revised Drainage April and 2008. Flood Control
6. Geotechnical Through, March Exploration 22, 2016, Report Earth Proposed Engineering 2500 Consultants, SF Fast Food LLC Restaurant with Drive-
APPENDIX A
HYDROLOGIC COMPUTATIONS
CHARACTER OF SURFACE: Runoff
Coefficient
Percentage
Streets, Parking Lots, Roofs, Alleys, and Drives: Impervious Calculations Project: By: North B. Mathisen College Drive Through
Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date:
Concrete …….......……………….….……….………………..….………………………………… 0.95 90%
Gravel ……….…………………….….…………………………..……………………………….. 0.50 40%
Roofs …….…….………………..……………….…………………………………………….. 0.95 90%
Lawns Pavers………………………….and Landscaping ..………………..…………………………………………….. 0.40 22%
Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0%
Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf
= 1.25
Basin ID Basin Area
(s.f.)
Basin Area
(ac)
Area of
Asphalt
(ac)
Area of
Concrete
(ac)
Area of
Roofs
(ac)
Area of
Gravel
(ac)
Area of
Lawns and
Landscaping
(ac)
2-year
Composite
Runoff
Coefficient
10-year
Composite
Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
Composite
% Imperv.
EX1 30222 0.69 0.00 0.00 0.00 0.00 0.69 0.25 0.25 0.31 0%
HISTORIC COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
Notes
April 7, 2016
10-year Cf = 1.00
**Soil Classification of site is Clayey Loam**
Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I.
Page 1 of 26 D:\Projects\1249-001\Drainage\Hydrology\1249-001_Rational-Calcs.xlsx\Hist-C-Values
Overland Flow, Time of Concentration:
Project: North College Drive Through
Calculations By:
Date:
Gutter/Swale Flow, Time of Concentration:
Tt = L / 60V
Tc = Ti + T
t (Equation RO-2)
Velocity (Gutter Flow), V = 20·S½
Velocity (Swale Flow), V = 15·S½
NOTE: C-value for overland flows over grassy surfaces; C = 0.25
Is Length
>500' ?
C*Cf
(2-yr
Cf=1.00)
C*Cf
(10-yr
Cf=1.00)
C*Cf
(100-yr
Cf=1.25)
Length,
L
(ft)
Slope,
S
(%)
Ti
2-yr
(min)
Ti
10-yr
(min)
Ti
100-yr
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
2-yr
Rational Method Equation: Project: North College Drive Through
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
ex1 EX1 0.69 19 19 18 0.25 0.25 0.31 1.65 2.82 6.01 0.29 0.49 1.30
HISTORIC RUNOFF COMPUTATIONS
Intensity,
i2
(in/hr)
Intensity,
i10
(in/hr)
Intensity,
i100
(in/hr)
Notes
B. Mathisen
April 7, 2016
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
Design
Point Basin(s)
Area, A
(acres)
2-yr
Tc
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
Flow,
Q2
(cfs)
Flow,
Q10
(cfs)
Flow,
Q100
(cfs)
C2 C10 C
100
Q C f C i A
Page 3 of 26 D:\Projects\1249-001\Drainage\Hydrology\1249-001_Rational-Calcs.xlsx\Hist-Direct-Runoff
CHARACTER OF SURFACE: Runoff
Coefficient
Percentage
Impervious Project: North College Drive Through
Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By:
Asphalt ……....……………...……….....…...……………….………………………………….0.. 95 100% Date:
Concrete …….......……………….….……….………………..….………………………………… 0.95 90%
Gravel ……….…………………….….…………………………..……………………………….0.. 50 40%
Roofs …….…….………………..……………….…………………………………………….. 0.95 90%
Pavers…………………………...………………..……………………………………………..0.40 22%
Lawns and Landscaping
Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0%
Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25
Basin ID Basin Area
(s.f.)
Basin Area
(ac)
Area of
Asphalt
(ac)
Area of
Concrete
(ac)
Area of
Roofs
(ac)
Area of
Gravel
(ac)
Area of
Pavers
(ac)
Area of
Lawns and
Landscaping
(ac)
2-year
Composite
Runoff
Coefficient
10-year
Composite
Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
Composite
% Imperv.
N1 9231 0.212 0.056 0.043 0.000 0.000 0.066 0.047 0.62 0.62 0.78 45%
S1 8751 0.201 0.105 0.041 0.000 0.000 0.043 0.013 0.79 0.79 0.99 70%
S2 6742 0.155 0.057 0.022 0.000 0.000 0.000 0.076 0.60 0.60 0.76 49%
N2 2680 0.062 0.000 0.000 0.062 0.000 0.000 0.000 0.95 0.95 1.00 90%
OS1 2038 0.047 0.000 0.000 0.000 0.000 0.000 0.047 0.25 0.25 0.31 0%
OS2 780 0.018 0.000 0.002 0.000 0.000 0.000 0.016 0.33 0.33 0.41 10%
TOTAL 30222 0.69 0.218 0.107 0.062 0.000 0.109 0.199 0.66 0.66 0.83 53%
DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I.
10-year Cf = 1.00
Overland Flow, Time of Concentration:
Project: North College Drive Through
Calculations By:
Date:
Gutter/Swale Flow, Time of Concentration:
Tt = L / 60V
Tc = Ti + Tt (Equation RO-2)
Velocity (Gutter Flow), V = 20·S½
Velocity (Swale Flow), V = 15·S½
NOTE: C-value for overland flows over grassy surfaces; C = 0.25
Is Length
>500' ?
(C*2-Cf yr
Cf=1.00)
(10-C*Cf yr
Cf=1.00)
(100-C*Cf yr
Cf=1.25)
Length,
L
(ft)
Slope,
S
(%)
2-Ti yr
(min)
10-Ti yr
(min)
100-Ti yr
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
(min) Tt
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
(min) Tt
2-yr
(min) Tc
10-yr
(min) Tc
100-yr
(min) Tc
N N1 No 0.62 0.62 0.78 46 2.20% 4.6 4.6 3.1 102 0.70% 1.67 1.0 N/A N/A N/A 6 6 5
S S1 No 0.79 0.79 0.99 45 2.60% 2.8 2.8 1.0 96 0.60% 1.55 1.0 N/A N/A N/A 5 5 5
S S2 No 0.60 0.60 0.76 12 2.50% 2.3 2.3 1.6 100 1.75% 2.65 0.6 N/A N/A N/A 5 5 5
N N2 No 0.95 0.95 1.00 16 2.00% 0.9 0.9 0.6 105 1.30% 2.28 0.8 N/A N/A N/A 5 5 5
Rational Method Equation: Project: North College Drive Through
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
N N1 0.21 6 6 5 0.62 0.62 0.78 2.76 4.72 9.95 0.36 0.62 1.64
S S1 0.20 5 5 5 0.79 0.79 0.99 2.85 4.87 9.95 0.45 0.77 1.97
S S2 0.15 5 5 5 0.60 0.60 0.76 2.85 4.87 9.95 0.27 0.46 1.16
N N2 0.06 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.17 0.28 0.61
os1 os2 OS1 OS2 0.0.05 02 8 8 8 0.25 0.25 0.31 2.40 4.10 8.59 0.03 0.05 0.13
5 5 5 0.33 0.33 0.41 2.85 4.87 9.95 0.02 0.03 0.07
DEVELOPED RUNOFF COMPUTATIONS
Design C100 Notes
Point
Flow,
Q100 (cfs)
Flow,
(cfs) Q2
10-yr
(min) Tc
2-yr
(min) Tc
C2
Flow,
(Q10 cfs)
Intensity,
(in/i100 hr)
Basin(s)
B. Mathisen
July 26th, 2016
Intensity,
(in/i10 hr)
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
Area, A C10
(acres)
Intensity,
(in/i2 hr)
100-yr
(min) Tc
Q C f C i A
Page 6 of 26 D:\Projects\1249-001\Drainage\Hydrology\1249-001_Rational-Calcs.xlsx\Direct-Runoff
CHARACTER OF SURFACE: Runoff
Coefficient
Percentage
Streets, Parking Lots, Roofs, Alleys, and Drives: Impervious Calculations Project: By: North College Drive Through
Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date:
Concrete …….......……………….….……….………………..….………………………………… 0.95 90%
Gravel ……….…………………….….…………………………..……………………………….. 0.50 40%
Roofs …….…….………………..……………….…………………………………………….. 0.95 90%
Lawns Pavers………………………….and Landscaping ..………………..…………………………………………….. 0.40 22%
Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0%
Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25
Design Point Basin IDs Basin Area
(s.f.)
Basin Area
(ac)
Area of
Asphalt
(ac)
Area of
Concrete
(ac)
Area of
Roofs
(ac)
Area of
Gravel
(ac)
Area of
Pavers
(ac)
Area of
Lawns and
Landscaping
(ac)
2-year
Composite
Runoff
Coefficient
10-year
Composite
Runoff
Coefficient
100-year
Composite
Runoff
Coefficient
Composite
% Imperv.
N S N1 S1 & & S2 N2 11911 15493 0.0.273 356 0.0.056 162 0.0.043 062 0.0.062 000 0.0.000 000 0.0.066 043 0.0.047 089 0.0.70 71 0.0.70 71 0.0.87 89 55% 61%
COMBINED DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
April 7, 2016
**Soil Classification of site is Clayey Loam**
10-year Cf = 1.00
Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table 3-3. % Impervious taken from UDFCD USDCM, Volume I.
B. Mathisen
Page 7 of 26 D:\Projects\1249-001\Drainage\Hydrology\1249-001_Rational-Calcs.xlsx\Comb-C-Values
Overland Flow, Time of Concentration:
Project: North College Drive Through
Calculations By:
Date:
Gutter/Swale Flow, Time of Concentration:
Tt = L / 60V
Tc = Ti + T
t (Equation RO-2)
Velocity (Gutter Flow), V = 20·S½
Velocity (Swale Flow), V = 15·S½
NOTE: C-value for overland flows over grassy surfaces; C = 0.25
Is Length
>500' ?
C*Cf
(2-yr
Cf=1.00)
C*Cf
(10-yr
Cf=1.00)
C*Cf
(100-yr
Cf=1.25)
Length,
L
(ft)
Slope,
S
(%)
Ti
2-yr
(min)
Ti
10-yr
(min)
Ti
100-yr
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
Length,
L
(ft)
Slope,
S
(%)
Velocity,
V
(ft/s)
Tt
(min)
2-yr
Rational Method Equation: Project: North College Drive Through
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
N N1 & N2 0.27 6 6 5 0.70 0.70 0.87 2.76 4.72 9.95 0.5 0.9 2.4
S S1 & S2 0.36 5 5 5 0.71 0.71 0.89 2.85 4.87 9.95 0.7 1.2 3.1
COMBINED DEVELOPED RUNOFF COMPUTATIONS
B. Mathisen
July 26th, 2016
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
Design
Point Basin(s)
Area, A
(acres)
2-yr
Tc
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
Flow,
Q2
(cfs)
Flow,
Q10
(cfs)
Flow,
Q100
(cfs)
C2 C10 C
100
Intensity,
i2
(in/hr)
Intensity,
i10
(in/hr)
Intensity,
i100
(in/hr)
Q C f C i A
Page 9 of 26 D:\Projects\1249-001\Drainage\Hydrology\1249-001_Rational-Calcs.xlsx\Comb-Direct-Runoff
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C100
2-yr
(min) Tc
100-yr
(min) Tc
(cfs) Q2
(Q100 cfs)
N N1 0.212 0.62 0.78 5.7 5.0 0.36 1.64
S S1 0.201 0.79 0.99 5.0 5.0 0.45 1.97
S S2 0.155 0.60 0.76 5.0 5.0 0.27 1.16
N N2 0.062 0.95 1.00 5.0 5.0 0.17 0.61
os1 OS1 0.047 0.25 0.31 8.3 7.7 0.03 0.13
os2 OS2 0.018 0.33 0.41 5.0 5.0 0.02 0.07
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C100
2-yr
(min) Tc
100-yr
(min) Tc
(cfs) Q2
(Q100 cfs)
ex1 EX1 0.694 0.25 0.31 19.4 18.0 0.29 1.30
Page 10 of 26 D:\Projects\1249-001\Drainage\Hydrology\1249-001_Rational-Calcs.xlsx\SUMMARY-TABLE
APPENDIX B
HYDRAULIC COMPUTATIONS
B.1 – Storm Sewers
B.2 – Inlets
B.3 – Detention Facilities
APPENDIX B.1
STORM SEWERS (FOR FUTURE USE)
APPENDIX B.2
INLETS (FOR FUTURE USE)
APPENDIX B.3
DETENTION FACILITIES
Pond No :
N
100-yr
0.87
5.00 min 2699 ft3
0.27 acres 0.062 ac-ft
Max Release Rate = 0.11 cfs
Time (min)
Ft Collins
100-yr
Intensity
(in/hr)
Inflow
Volume
(ft3)
Outflow
Adjustment
Factor
(Qav cfs)
Outflow Volume
(ft3)
Storage
Volume
(ft3)
5 9.950 701 1.00 0.11 33 668
10 7.720 1088 0.75 0.08 50 1039
15 6.520 1378 0.67 0.07 66 1312
20 5.600 1579 0.63 0.07 83 1496
25 4.980 1755 0.60 0.07 99 1656
30 4.520 1911 0.58 0.06 116 1796
35 4.080 2013 0.57 0.06 132 1881
40 3.740 2108 0.56 0.06 149 1960
45 3.460 2194 0.56 0.06 165 2029
50 3.230 2276 0.55 0.06 182 2095
55 3.030 2349 0.55 0.06 198 2151
60 2.860 2419 0.54 0.06 215 2204
65 2.720 2492 0.54 0.06 231 2261
70 2.590 2555 0.54 0.06 248 2308
75 2.480 2621 0.53 0.06 264 2357
80 2.380 2683 0.53 0.06 281 2403
85 2.290 2743 0.53 0.06 297 2446
90 2.210 2803 0.53 0.06 314 2490
95 2.130 2852 0.53 0.06 330 2522
100 2.060 2903 0.53 0.06 347 2557
105 2.000 2960 0.52 0.06 363 2597
110 1.940 3008 0.52 0.06 380 2628
115 1.890 3063 0.52 0.06 396 2667
120 1.840 3112 0.52 0.06 413 2699
*Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2.
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Input Variables Results
Required Detention Volume
Fort Collins, Colorado
1249-001
North College Drive-Thru
Project Number :
Project Name :
Pond N
A =
Tc =
Pond No :
S
100-yr
0.86
5.00 min 3577 ft3
0.36 acres 0.082 ac-ft
Max Release Rate = 0.14 cfs
Time (min)
Ft Collins
100-yr
Intensity
(in/hr)
Inflow
Volume
(ft3)
Outflow
Adjustment
Factor
(Qav cfs)
Outflow Volume
(ft3)
Storage
Volume
(ft3)
5 9.950 924 1.00 0.14 42 882
10 7.720 1434 0.75 0.11 63 1371
15 6.520 1817 0.67 0.09 84 1733
20 5.600 2081 0.63 0.09 105 1976
25 4.980 2313 0.60 0.08 126 2187
30 4.520 2519 0.58 0.08 147 2372
35 4.080 2653 0.57 0.08 168 2485
40 3.740 2779 0.56 0.08 189 2590
45 3.460 2892 0.56 0.08 210 2682
50 3.230 3000 0.55 0.08 231 2769
55 3.030 3096 0.55 0.08 252 2844
60 2.860 3188 0.54 0.08 273 2915
65 2.720 3284 0.54 0.08 294 2990
70 2.590 3368 0.54 0.08 315 3053
75 2.480 3455 0.53 0.07 336 3119
80 2.380 3537 0.53 0.07 357 3180
85 2.290 3616 0.53 0.07 378 3238
90 2.210 3695 0.53 0.07 399 3296
95 2.130 3759 0.53 0.07 420 3339
100 2.060 3827 0.53 0.07 441 3386
105 2.000 3901 0.52 0.07 462 3439
110 1.940 3964 0.52 0.07 483 3481
115 1.890 4037 0.52 0.07 504 3533
120 1.840 4102 0.52 0.07 525 3577
*Note: Using the method described in Urban Storm Drainage Criteria Manual Volume 2.
A =
Tc =
Project Location :
Design Point
C =
Design Storm
DETENTION POND CALCULATION; MODIFIED FAA METHOD w/ Ft Collins IDF
Input Variables Results
Required Detention Volume
Fort Collins, Colorado
1249-001
APPENDIX C
WATER QUALITY DESIGN COMPUTATIONS
Project Title Date:
Project Number Calcs By:
Client
Pond Designation
0.8
WQCV = Watershed inches of Runoff (inches) 45.00%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100) 0.154 in
A = 0.21 ac
V = 0.0027 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
North College Drive-Thru April 7, 2016
1249-001 B.Mathisen
WQCV Underground Pond N (Basin N1)
119 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
0.154
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
WQCV (watershed inches)
Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
WQCV a 0.91 i 3 1 . 19 i 2 0 . 78 i
WQCV a 0.91 i 3 1 . 19 i 2 0 . 78 i
V 12 * A
WQCV
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Type of Permeable Pavement Section
A) What type of section of permeable pavement is used?
(Based on the land use and activities, proximity to adjacent
structures and soil characteristics.)
B) What type of wearing course?
2. Required Storage Volume
A) Effective Imperviousness of Area Tributary to Permeable Pavement, Ia Ia
= 45.0 %
B) Tributary Area's Imperviousness Ratio (I = Ia / 100) i = 0.450
C) Tributary Watershed Area ATotal = 9,231 sq ft
(including area of permeable pavement system)
D) Area of Permeable Pavement System APPS = 2,875 sq ft
(Minimum recommended permeable pavement area = 1695 sq ft)
E) Impervious Tributary Ratio RT = 1.0
(Contributing Imperviuos Area / Permeable Pavement Ratio)
F) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 119 cu ft
(WQCV = (0.8 * (0.91 * i3
- 1.19 * i2
+ 0.78 * i) / 12) * Area)
G) Is flood control volume being added?
H) Total Volume Needed VTotal = cu ft
3. Depth of Reservoir
A) Minimum Depth of Reservoir Dmin = 10.0 inches
(Minimum recommended depth is 6 inches)
B) Is the slope of the reservoir/subgrade interface equal to 0%?
C) Porosity (Porous Gravel Pavement < 0.3, Others < 0.40) P = 0.30
D) Slope of the Base Course/Subgrade Interface S = ft / ft
E) Length Between Lateral Flow Barriers L = ft
F) Volume Provided Based on Depth of Base Course V = 647 cu ft
Flat or Stepped: V = P * ((Dmin-1)/12) * Area
Sloped: V = P * [(Dmin - (Dmin
- 6*SL-1)) / 12] * Area
4. Lateral Flow Barriers
A) Type of Lateral Flow Barriers
B) Number of Permeable Pavement Cells Cells = 1
5. Perimeter Barrier
A) Is a perimeter barrier provided on all sides of the
pavement system?
(Recommeded for PICP, concrete grid pavement, or for any
no-infiltration section.)
North College Drive Thru
Basin N1
Design Procedure Form: Permeable Pavement Systems (PPS)
Blaine Mathisen
Northern Engineering
July 26, 2016
Choose One
No Infiltration
Partial Infiltration Section
Full Infiltration Section
Choose One
YES
NO
Choose One
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
6. Filter Material and Underdrain System
A) Is the underdrain placed below a 6-inch thick layer of
CDOT Class C filter material?
B) Diameter of Slotted Pipe (slot dimensions per Table PPs-2)
Detention Vault no Underdrain
C) Distance from the Lowest Elevation of the Storage Volume y = 0.3 ft
(i.e. the bottom of the base course to the center of the orifice)
7. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is there a minimum 30 mil thick impermeable PVC geomembrane
liner on the bottom and sides of the basin, extending up to the top
of the base course?
B) CDOT Class B Separator Fabric
8. Outlet
(Assumes each cell has similar area, subgrade slope, and length
between lateral barriers (unless subgrade is flat). Calculate cells
individually where this varies.)
A) Depth of WQCV in the Reservoir DWQCV = 1.65 inches
(Elevation of the Flood Control Outlet)
B) Diameter of Orifice for 12-hour Drain Time DOrifice = 0.37 inches MINIMUM ORIFICE SIZE IS 3/8-INCHES
(Use a minimum orifice diameter of 3/8-inches)
Notes:
North College Drive Thru
Design Procedure Form: Permeable Pavement Systems (PPS)
Blaine Mathisen
Northern Engineering
July 26, 2016
Basin N1
Choose YESOne
NO
Choose One
4-inch
6-inch
Choose One
Choose One
YES
NO
Placed above the liner
Placed above and below the liner
N/A
1249-001 Basin N1 PAVER UD-BMP_v3.02.xls, PPS 7/26/2016, 2:12 PM
Project Title Date:
Project Number Calcs By:
Client
Pond Designation
0.8
WQCV = Watershed inches of Runoff (inches) 90.00%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100) 0.321 in
A = 0.06 ac
V = 0.0017 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
72 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
North College Drive-Thru April 7, 2016
1249-001 B.Mathisen
Underground Pond N (Basin N2)
0.321
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
WQCV (watershed inches)
Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
WQCV a 0.91 i 3 1 . 19 i 2 0 . 78 i
WQCV a 0.91 i 3 1 . 19 i 2 0 . 78 i
V 12 * A
WQCV
Project Title Date:
Project Number Calcs By:
Client
Pond Designation
0.8
WQCV = Watershed inches of Runoff (inches) 70.00%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100) 0.220 in
A = 0.20 ac
V = 0.0037 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
161 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
North College Drive-Thru April 7, 2016
1249-001 B.Mathisen
Basin S1
0.220
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
WQCV (watershed inches)
Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
WQCV a 0.91 i 3 1 . 19 i 2 0 . 78 i
WQCV a 0.91 i 3 1 . 19 i 2 0 . 78 i
V 12 * A
WQCV
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Type of Permeable Pavement Section
A) What type of section of permeable pavement is used?
(Based on the land use and activities, proximity to adjacent
structures and soil characteristics.)
B) What type of wearing course?
2. Required Storage Volume
A) Effective Imperviousness of Area Tributary to Permeable Pavement, Ia Ia
= 70.0 %
B) Tributary Area's Imperviousness Ratio (I = Ia / 100) i = 0.700
C) Tributary Watershed Area ATotal = 7,242 sq ft
(including area of permeable pavement system)
D) Area of Permeable Pavement System APPS = 1,859 sq ft
(Minimum recommended permeable pavement area = 1878 sq ft)
E) Impervious Tributary Ratio RT = 2.0 IMPERVIOUS TRIBUTARY RATIO EXCEEDS 2.0
(Contributing Imperviuos Area / Permeable Pavement Ratio)
F) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 133 cu ft
(WQCV = (0.8 * (0.91 * i3
- 1.19 * i2
+ 0.78 * i) / 12) * Area)
G) Is flood control volume being added?
H) Total Volume Needed VTotal = cu ft
3. Depth of Reservoir
A) Minimum Depth of Reservoir Dmin = 10.0 inches
(Minimum recommended depth is 6 inches)
B) Is the slope of the reservoir/subgrade interface equal to 0%?
C) Porosity (Porous Gravel Pavement < 0.3, Others < 0.40) P = 0.30
D) Slope of the Base Course/Subgrade Interface S = ft / ft
E) Length Between Lateral Flow Barriers L = ft
F) Volume Provided Based on Depth of Base Course V = 418 cu ft
Flat or Stepped: V = P * ((Dmin-1)/12) * Area
Sloped: V = P * [(Dmin - (Dmin
- 6*SL-1)) / 12] * Area
4. Lateral Flow Barriers
A) Type of Lateral Flow Barriers
B) Number of Permeable Pavement Cells Cells = 1
5. Perimeter Barrier
A) Is a perimeter barrier provided on all sides of the
pavement system?
(Recommeded for PICP, concrete grid pavement, or for any
no-infiltration section.)
North College Drive Thru
Basin S1
Design Procedure Form: Permeable Pavement Systems (PPS)
Blaine Mathisen
Northern Engineering
July 26, 2016
Choose One
No Infiltration
Partial Infiltration Section
Full Infiltration Section
Choose One
YES
NO
Choose One
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
6. Filter Material and Underdrain System
A) Is the underdrain placed below a 6-inch thick layer of
CDOT Class C filter material?
B) Diameter of Slotted Pipe (slot dimensions per Table PPs-2)
Detention Vault no Underdrain
C) Distance from the Lowest Elevation of the Storage Volume y = 0.3 ft
(i.e. the bottom of the base course to the center of the orifice)
7. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is there a minimum 30 mil thick impermeable PVC geomembrane
liner on the bottom and sides of the basin, extending up to the top
of the base course?
B) CDOT Class B Separator Fabric
8. Outlet
(Assumes each cell has similar area, subgrade slope, and length
between lateral barriers (unless subgrade is flat). Calculate cells
individually where this varies.)
A) Depth of WQCV in the Reservoir DWQCV = 2.86 inches
(Elevation of the Flood Control Outlet)
B) Diameter of Orifice for 12-hour Drain Time DOrifice = 0.39 inches
(Use a minimum orifice diameter of 3/8-inches)
Notes:
Basin S1
North College Drive Thru
Design Procedure Form: Permeable Pavement Systems (PPS)
Blaine Mathisen
Northern Engineering
July 26, 2016
Choose YESOne
NO
Choose One
4-inch
6-inch
Choose One
Choose One
YES
NO
Placed above the liner
Placed above and below the liner
N/A
1249-001 Basin S1 PAVER UD-BMP_v3.02.xls, PPS 7/26/2016, 2:13 PM
Project Title Date:
Project Number Calcs By:
Client
Pond Designation
0.8
WQCV = Watershed inches of Runoff (inches) 49.00%
a = Runoff Volume Reduction (constant)
i = Total imperviousness Ratio (i = Iwq/100) 0.163 in
A = 0.16 ac
V = 0.0021 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
North College Drive-Thru April 7, 2016
1249-001 B.Mathisen
Rain Garden S2
92 cu. ft.
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
0.163
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
WQCV (watershed inches)
Total Imperviousness Ratio (i = Iwq/100)
Water Quality Capture Volume
6 hr
12 hr
24 hr
40 hr
WQCV a 0.91 i 3 1 . 19 i 2 0 . 78 i
WQCV a 0.91 i 3 1 . 19 i 2 0 . 78 i
V 12 * A
WQCV
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 49.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.490
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.16 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 6,742 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = 0.43 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER = 91.5 cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum) DWQCV = 12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin = 61 sq ft
D) Actual Flat Surface Area AActual = 329 sq ft
E) Area at Design Depth (Top Surface Area) ATop = 1073 sq ft
F) Rain Garden Total Volume VT= 701 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y = 1.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = 91 cu ft
iii) Orifice Diameter, 3/8" Minimum DO = 0.25 in MINIMUM DIAMETER = 3/8"
Design Procedure Form: Rain Garden (RG)
Blaine Mathisen
Northern Engineering
July 26, 2016
North College Avenue Drive Thru
Basin S2
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
1249-001 Basin S2 RAIN GARDEN UD-BMP_v3.02.xls, RG 7/26/2016, 2:23 PM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
PROVIDE A 30 MIL (MIN) PVC LINER WITH CDOT CLASS B
GEOTEXTILE ABOVE IT. USE THE SAME GEOTEXTILE BELOW THE
LINER IF THE SUBGRADE IS ANGULAR
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
Blaine Mathisen
Northern Engineering
July 26, 2016
North College Avenue Drive Thru
Basin S2
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
1249-001 Basin S2 RAIN GARDEN UD-BMP_v3.02.xls, RG 7/26/2016, 2:23 PM
APPENDIX D
EROSION CONTROL REPORT
North College Drive Through
Final Erosion Control Report
A with comprehensive the final construction Erosion and drawings. Sediment It should Control be Plan noted, (along however, with associated that any such details) Erosion will be and
included
Sediment the BMPs Control depicted, Plan and serves additional only as or a different general BMPs guide from to the those Contractor. included Staging may be and/necessary or phasing
during of
construction, or as required by the authorities having jurisdiction.
It maintained shall be the and responsibility followed. The of the Erosion Contractor and Sediment to ensure Control erosion Plan control is intended measures to be are a properly living
document, location of BMPs constantly as they adapting are installed, to site conditions removed or and modified needs. in The conjunction Contractor with shall construction update the
activities. It is imperative to appropriately reflect the current site conditions at all times.
The during Erosion construction, and Sediment as well Control as permanent Plan shall erosion address control both protection. temporary measures Best Management to be implemented Practices
from not limited the Volume to, silt 3, fencing Chapter along 7 – the Construction disturbed perimeter, BMPs will gutter be utilized. protection Measures in the may adjacent include,
roadways but are
and clean-inlet up procedures, protection at designated proposed storm concrete inlets. washout Vehicle areas, tracking dumpsters, control and pads, job spill site containment restrooms
shall and
also be provided by the Contractor.
Grading Plans at and final Erosion design will Control also Notes contain can a be full-found size Erosion on Sheet Control CS2 of Plan the as Utility well Plans. as a separate The Utility
sheet
dedicated Contractor to shall Erosion be aware Control of, Details. and adhere In addition to, the applicable to this report requirements and the referenced outlined in plan any sheets,
existing the
Development to issuance of Agreement(the Development s) of record, Construction as well Permit. as the Development Also, the Site Agreement, Contractor to for be this recorded project
prior will
be Public required Health to and secure Environment a Stormwater (CDPHE)Construction , Water General Quality Control Permit Division from the – Colorado Stormwater Department Program,
of
before shall develop commencing a comprehensive any earth disturbing StormWater activities. Management Prior to Plan securing (SWMP) said pursuant permit, to the CDPHE Site Contractor
requirements inspections, and and maintenance guidelines. The of construction SWMP will BMPs. further describe and document the ongoing activities,
MAP POCKET
HISTORIC DRAINAGE EXHIBIT
PROPOSED DRAINAGE EXHIBIT
D
EV
os1
N
S
NORTH COLLEGE AVE.
SCHRADER P.U.D.
FFE = 84.25
NORTH COLLEGE
MOBILE HOME PARK
NORTH
COLLEGE
MOBILE HOME
PARK
N1
S1
S2
N2
OS2
OS1
os2
PRIVATE DRIVE
RAIN GARDEN 1
UNDERGROUND
POND S (SC-310)
UNDERGROUND
POND S (SC-310)
UNDERGROUND
POND S (SC-310)
UNDERGROUND
POND N (SC-160)
2' CONCRETE
VALLEY PAN
ISOLATOR ROW
ISOLATOR ROW
EMERGENCY OVERFLOW
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what'sbelow.
Call before you dig.
R
GRAPHIC SCALE:
LEGEND:
ST
A2
a3
4950
RUNOFF SUMMARY TABLE:
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
NOTES:
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C100
2-yr
D
V.P.
C
S
C
S
NORTH COLLEGE AVE.
SCHRADER P.U.D.
LOT 2
NORTH COLLEGE
MOBILE HOME PARK
NORTH
COLLEGE
MOBILE HOME
PARK
EX1
LOT 1
EX1
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what'sbelow.
Call before you dig.
R
GRAPHIC SCALE:
LEGEND:
ST
A2
a3
4950
RUNOFF SUMMARY TABLE:
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
NOTES:
BASIN
ID
TOTAL
AREA
(acres)
C2 C100
2-yr
Tc
(min)
100-yr
Tc
(min)
Q2
(cfs)
Q100
(cfs)
EX1 0.075 0.25 0.31 7.9 7.4 0.05 0.21
( IN FEET )
10 0 10 20 30
1 INCH = 10 FEET
NORTH
Sheet
Of 8 Sheets
NORTH COLLEGE DRIVE THROUGH These drawings are
instruments of service
provided by Northern
Engineering Services, Inc.
and are not to be used for
any type of construction
unless signed and sealed by
a Professional Engineer in
the employ of Northern
Engineering Services, Inc.
NOT FOR CONSTRUCTION
REVIEW SET
301 North Howes Street, Suite 100
Fort Collins, Colorado 80521
E NGINEER ING
N O R T H E RN
PHONE: 970.221.4158
www.northernengineering.com
C4.01
HISTORIC DRAINAGE EXHIBIT
8
Tc
(min)
100-yr
Tc
(min)
Q2
(cfs)
Q100
(cfs)
N N1 0.212 0.62 0.78 5.7 5.0 0.36 1.64
S S1 0.201 0.79 0.99 5.0 5.0 0.45 1.97
S S2 0.155 0.60 0.76 5.0 5.0 0.27 1.16
N N2 0.062 0.95 1.00 5.0 5.0 0.17 0.61
os1 OS1 0.047 0.25 0.31 8.3 7.7 0.03 0.13
os2 OS2 0.018 0.33 0.41 5.0 5.0 0.02 0.07
( IN FEET )
10 0 10 20 30
1 INCH = 10 FEET
NORTH
Sheet
Of 8 Sheets
NORTH COLLEGE DRIVE THROUGH These drawings are
instruments of service
provided by Northern
Engineering Services, Inc.
and are not to be used for
any type of construction
unless signed and sealed by
a Professional Engineer in
the employ of Northern
Engineering Services, Inc.
NOT FOR CONSTRUCTION
REVIEW SET
301 North Howes Street, Suite 100
Fort Collins, Colorado 80521
E NGINEER ING
N O R T H E RN
PHONE: 970.221.4158
www.northernengineering.com
C4.00
DRAINAGE EXHIBIT
7
12 hr
YES- Flat or Stepped Installation
NO- Sloped Installation
Choose One
Concrete Walls
PVC geomembrane installed normal to flow
N/A- Flat installation
Other (Describe):
Choose YESOne
NO
Choose One
PICP
Concrete Grid Pavement
Pervious Concrete
Porous Gravel
1249-001 Basin S1 PAVER UD-BMP_v3.02.xls, PPS 7/26/2016, 2:13 PM
12 hr
12 hr
YES- Flat or Stepped Installation
NO- Sloped Installation
Choose One
Concrete Walls
PVC geomembrane installed normal to flow
N/A- Flat installation
Other (Describe):
Choose YESOne
NO
Choose One
PICP
Concrete Grid Pavement
Pervious Concrete
Porous Gravel
1249-001 Basin N1 PAVER UD-BMP_v3.02.xls, PPS 7/26/2016, 2:12 PM
12 hr
North College Drive-Thru
Project Number :
Project Name :
Pond S
Page 1 of 1
1249-001_Pond S_DetentionVolume_FAAModified Method.xls
Project Location :
Design Point
C =
Design Storm
Page 1 of 1
1249-001_Pond N_DetentionVolume_FAAModified Method.xls
Tc
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
N N1 & N2 No 0.62 0.62 0.78 0.02 4.65 4.65 3.13 0.01 1.67 1.02 N/A N/A N/A 6 6 5
S S1 & S2 No 0.79 0.79 0.99 0.03 2.83 2.83 1.03 0.01 1.55 1.03 N/A N/A N/A 5 5 5
COMBINED DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
B. Mathisen
July 26th, 2016
Design
Point Basin IDs
Overland Flow Pipe Flow Swale Flow Time of Concentration
(Equation RO-4)
1 3
1 . 87 1 . 1 *
S
Ti C Cf L
Page 8 of 26 D:\Projects\1249-001\Drainage\Hydrology\1249-001_Rational-Calcs.xlsx\Comb-Tc-10-yr_&_100-yr
os1 os2 OS1 OS2 No No 0.25 0.25 0.31 21 0.67% 8.3 8.3 7.7 N/A N/A N/A N/A N/A N/A 8 8 8
0.33 0.33 0.41 14 1.50% 4.7 4.7 4.2 N/A N/A N/A N/A N/A N/A 5 5 5
DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
Gutter Flow Swale Flow
Design
Point Basin
Overland Flow
B. Mathisen
July 26th, 2016
Time of Concentration
(Equation RO-4)
1 3
1 . 87 1 . 1 *
S
Ti C Cf L
Page 5 of 26 D:\Projects\1249-001\Drainage\Hydrology\1249-001_Rational-Calcs.xlsx\Tc-10-yr_&_100-yr
July 26th, 2016
**Soil Classification of site is Clayey Loam**
B. Mathisen
Page 4 of 26 D:\Projects\1249-001\Drainage\Hydrology\1249-001_Rational-Calcs.xlsx\C-Values
Tc
(min)
10-yr
Tc
(min)
100-yr
Tc
(min)
ex1 EX1 No 0.25 0.25 0.31 139 0.90% 19.4 19.4 18.0 N/A N/A N/A N/A N/A N/A 19 19 18
HISTORIC TIME OF CONCENTRATION COMPUTATIONS
B. Mathisen
April 7, 2016
Design
Point Basin
Overland Flow Gutter Flow Swale Flow Time of Concentration
(Equation RO-4)
1 3
1 . 87 1 . 1 *
S
Ti C Cf L
Page 2 of 26 D:\Projects\1249-001\Drainage\Hydrology\1249-001_Rational-Calcs.xlsx\Hist-Tc-10-yr_&_100-yr