HomeMy WebLinkAboutELEVATIONS CREDIT UNION - PDP - PDP160021 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT
Elevations Credit Union
Fort Collins, Colorado
July 12th, 2016
Elevations Prepared Credit Union for:
1526 Fort E. Harmony Collins, Colorado Road, Unit 80525 130
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: 207-016
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.
July 12, 2016
City of Fort Collins
Stormwater 700 Wood Street Utility
Fort Collins, Colorado 80521
RE: Elevations Preliminary Credit Drainage Union Report for
Dear Staff:
Northern Engineering is pleased to submit this Preliminary Drainage Report for your review. This
report accompanies the Conceptual Review submittal for the proposed Elevations Credit Union.
This Manual report (FCSCM) has been and prepared the Urban in Drainage accordance and with Flood the Control City of District Fort Collins (UDFCD) Stormwater Urban Criteria Storm
Drainage proposed Criteria Elevations Manual Credit and Union serves project. to document We understand the stormwater that review impacts by the associated City of Fort with Collins
the is
to assure general compliance with standardized criteria.
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
Elevations Credit Union
Preliminary 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 ........................................................................................................................................................................................................
. 6 6
B. Four Step Process .............................................................................................................................. 6
C. Development Criteria Reference and Constraints ............................................................................ 7
D. Hydrological Criteria ......................................................................................................................... 7
E. Hydraulic Criteria .............................................................................................................................. 7
F. Floodplain Regulations Compliance .................................................................................................. 7
G. Modifications of Criteria ................................................................................................................... 8
IV. A. General DRAINAGE Concept FACILITY ...........DESIGN .......................................................................................................................................................................................................
. 8 8
B. Specific Details ................................................................................................................................ 10
V. A. Compliance CONCLUSIONS with .Standards ...............................................................................................................................................................................................................
.. 12 12
B. Drainage Concept ............................................................................................................................ 12
References ....................................................................................................................... 13
APPENDICES: APPENDIX A – Hydrologic Computations
APPENDIX B B.1 – – Hydraulic Storm Sewers Computations (For Future Use)
B.B.3 2 – – Detention Inlets Facilities
APPENDIX APPENDIX C D – – Water Erosion Quality Control Design Report Computations
APPENDIX E – Soils Resource Report
Elevations Credit Union
Preliminary Drainage Report
LIST OF TABLES AND FIGURES:
Figure Figure 1 2 Vicinity Aerial Photograph Map ............................................................................................................................................................................................................
. 1 2
Figure Figure 3 4 Proposed FEMA Map Site ....Plan ........................................................................................................................................................................................................
. 4 3
Figure 5 City Floodplain Mapping .......................................................................................... 4
MAP C400 POCKET: – Proposed Drainage Exhibit
C401 – Historic Drainage Exhibit
Elevations Credit Union
Preliminary Drainage Report 1
I. GENERAL LOCATION AND DESCRIPTION
A. Location
1. Vicinity Map
Figure 1 Vicinity Map
2. Elevations of Principal the northeast Meridian, Credit quarter Union City project of of Fort Section Collins, site 23, is located Township County in of the 7 Larimer, North, east
half Range State of the of 69 Colorado. southeast West of the quarter 6th
3. The intersection project site of College is located Avenue at 2025 and Arthur College Drive. Avenue at northwest corner of the
4. The and curb project and site gutter lies within north towards the Spring Spring Creek Creek, Basin. and The it ultimately site drains discharges via overland into flow the
Cache feet (0.La 548 Poudre ac.) and River. detention The proposed is required. impervious The site area still for must the provide site is 23,current 862 square City
Low treatment Impact methods Design are (LID) described requirements in further and detail water below. quality treatment. Water quality
5. As this is an in-fill site, the area surrounding the site is fully developed.
Elevations Credit Union
Preliminary Drainage Report 2
6. Offsite staying flows within from the Arthur asphalt, Drive curb, from and the gutter south, for crosses Arthur Drive. the southwest No offsite corner flows the from site the
north, east or west enters the site.
B. Description of Property
1. Elevations Credit Union project is approximately 0.72 net acres.
Figure 2 Aerial Photograph
2. The concrete, subject and property landscaping is currently along composed College Avenue of an and abandoned the west gas end station, of the site. asphalt, Existing
ground A large slopes retaining are wall mild divides (i.e. 1 the – 4%upper ±) through two-thirds the from eastern Spring two-Court thirds to of the the west. property.
Existing slopes from slopes south for to the north. wester third range from 5:1 to 3%±. General topography
3. According Conservation to the Service United (NRCS) States Soil Department Survey, the of site Agriculture consists (USDA) of Altvan-Natural Satanta Resources loams,
which Appendix fall E. into Hydrologic Soil Groups B. The NRCS soils report is provided in
4. The property proposed to include development commercial is composed and financial of a services. proposed building A hardscape along parking the eastern lot with
landscaping sewer, storm islands sewer, is rain proposed. gardens, Associated and underground site work detention including will water, be constructed sanitary with
the implemented development. with Current the project, City and Low will Impact consist Design of several (LID) requirements LID features which will be are
discussed in Section IV, below.
Elevations Credit Union
Preliminary Drainage Report 3
Figure 3 Proposed Site Plan
5. There are no known irrigation laterals crossing the site.
6. The permitted project within site is this within zone a district. General Commercial District (C-G). The proposed use is
C. Floodplain
1. The Year northwest High Risk corner Flood area of the according project site to FIRM is encroached Panel 08069C87G by the FEMA for designated Larimer County, 100-
dated impact May on downstream 2, 2012. However, infrastructure, development as this in floodplain this area is will caused not have by the an obstruction adverse
of the College Avenue bridge.
Elevations Credit Union
Preliminary Drainage Report 4
Figure 4 FEMA Map
Figure 5 City Floodplain Mapping
Elevations Credit Union
Preliminary Drainage Report 5
II. DRAINAGE BASINS AND SUB-BASINS
A. Major Basin Description
1. The site are project to detain site lies the within difference the Spring between Creek the Basin. 100-year Detention developed requirements inflow rate for and this the
historic onsite gas 2-year station. release Historically, rate from the the site landscaping sheet flows areas all onsite associated runoff with directly the previous offsite
without release all any paved detention areas or and water release quality. the remaining However, Elevations portion at a Credit rate equal Union to will the free runoff
rate boundaries of the historic of the site. landscaping Water quality areas will along however the western be provided and eastern for the property all paved areas
via underground Stormtech chambers and rain gardens.
2. There Union are project no previous site. drainage studies for the area associated with Elevations Credit
B. Sub-Basin Description
Elevations the site has Credit historically Union flowed historically overland drains north overland towards from Spring south Creek to north. and Runoff eventually from
entering the Cache La Poudre.
Basin E
Basin the property. E encompasses Runoff generated 0.20 acres in this from basin the eastern has historically boundary sheet to roughly flowed 1/directly 3 east into into
College Creek. The Avenue previous and then development conveyed had north an via impervious curb and area gutter of 6,until 083 it sq. enters ft. associated Spring
with Basin E.
Basin W
Basin the property. W encompasses Runoff generated 0.52 acres in this from basin the western has historically boundary sheet to roughly flowed 2/offsite 3 west either into
into Spring Arthur Court Drive via curb or Spring and gutter Court. and All flow from that there entered the runoff Arthur is conveyed Drive eventually north towards reaches
Spring associated Creek. with The Basin previous W. development had an impervious area of 16,163 sq. ft.
The Elevations previous Credit development Union is proposing had a total a impervious total impervious area of area 22,of 249 23,sq. 356 ft. sq. and ft.
Therefore, development the 107 difference sq. ft. above in impervious the maximum area is allowable 1,107 sq. change ft. bringing requiring the proposed detention.
Below detention in Section is discussed. IV.B.2 a more detailed description of Elevations Credit Union
1. A Section more detailed IV.A.4., description below. of the projects proposed drainage patterns follows in
2. There are no offsite flows associated with Elevations Credit Union.
A Map full-Pocket size copy at the of the end Historic of this report. and Proposed Drainage Exhibit can be found in the
Elevations Credit Union
Preliminary Drainage Report 6
III. DRAINAGE DESIGN CRITERIA
A. Regulations
There Union are project. no optional provisions outside of the FCSCM proposed with the Elevations Credit
B. Four Step Process
The project overall utilizes stormwater the “Four management Step Process” strategy to minimize employed adverse with impacts the Elevations of urbanization Credit Union on
receiving incorporated waters. each The step. following is a description of how the proposed development has
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 south portion as much of the vegetated site to reduce open the areas overall as possible impervious along area the and north, to minimize east, west directly and
connected impervious areas (MDCIA).
Routing water quality flows, purposes. to the extent Stormwater feasible, will through be routed underground through Stormtech drain rock to Isolator increase Rows for
infiltration
Providing reduce loads regional on downstream detention to storm increase infrastructure. time of concentration, promote infiltration and
Routing runoff from the roof directly into isolator rows
Step Slow 2 Release – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with
The development efforts taken of this in Step intensity 1 will will facilitate still generate the reduction stormwater of runoff; runoff however, that will urban require
additional intercepted BMPs and treated and water using quality. underground The stormwater Stormtech runoff chambers from the site will be
Step 3 – Stabilize Drainageways
There seem applicable are no major to proposed drainageways development, within the the subject project property. indirectly While helps this achieve step may stabilized not
drainageways existed, sediment nonetheless. with erosion By potential providing is water removed quality from treatment, downstream where drainageway none previously
systems. well as ongoing Furthermore, monthly this stormwater project will utility pay fees, one-time both stormwater of which help development achieve City-fees, wide as
drainageway stability.
Step The proposed 4 – Implement project Site includes Specific a single and Other story building, Source Control associated BMPs. parking, retaining walls,
and controls pedestrian including: sidewalk paths all of which will require the need for site specific source
A localized trash enclosure placed in the parking lot.
The enhance proposed water development quality. The will Stormtech provide Isolator LID features Row within is designed Stormtech to capture Isolator the Rows first to
Elevations Credit Union
Preliminary Drainage Report 7
flush exposed of a to storm weathering event; and thus, runoff eliminating processes. sources of potential pollution previously left
C. Development Criteria Reference and Constraints
1. There are no known drainage studies for the existing property.
2. 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.
Release rates can not adversely impact existing infrastructure.
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)
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 previously noted, the subject property maintains historic drainage patterns.
2. All in accordance drainage facilities with criteria proposed outlined with in the the Elevations FCSCM and/Credit or the Union Urban project Drainage are designed and
Flood Control District’s (UDFCD) Urban Storm Drainage Criteria Manual.
3. As Year stated High in Risk Section Flood I.Fringe. C.1, above, However, the subject the proposed property project is encroaching does not a propose FEMA to 100-
modify any natural drainageways.
F. Floodplain Regulations Compliance
4. As Flood previously Fringe along mentioned, the northwest the project corner site of is the encroaching property. a However, FEMA 100-development Year High in Risk this
area is caused will not by have the obstruction an adverse of impact the College on downstream Avenue bridge. infrastructure, as this floodplain
Elevations Credit Union
Preliminary Drainage Report 8
G. Modifications of Criteria
The this time. proposed Elevations Credit Union development is not requesting modification at
IV. DRAINAGE FACILITY DESIGN
A. General Concept
1. The existing main drainage objectives patterns of the and Elevations ensure Credit no adverse Union impacts drainage to design any adjacent are to maintain properties
or existing infrastructure occurs.
2. As property. previously Additionally, mentioned, onsite there LID are feature no off-will site be flows provided draining which onto will the enhance existing
downstream water quality. These measures are discussed further below.
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 basins, proposed designated Elevations as Basins Credit W.Union 1, E.1, project R.1, OS.is associated 1, OS.2, and with OS.six 3. (6) Drainage major drainage
patterns described for below. proposed drainage basins as shown in the Proposed Drainage Exhibit are
Basin W.1
Basin landscaping W.1 has islands. a net Runoff area of generated 0.32 acres in which Basin has W.1 an will associated sheet flow parking as well lot as and curb
and parking gutter lot. flow Runoff east entering to west the until inlet it is will collected be conveyed by an inlet via storm along sewer the west pipes. side The of the
storm SC-740 sewer cells will each. convey The additional the runoff runoff into two will separate continue isolator to fill the rows non-containing isolator rows. four (4) The
isolator Once, Basin rows W.will 1 be goes wrapped through in the a geotextile water quality membrane it will be to released avoid sediment into a sidewalk migration.
chase historically within routed. Spring Court. Once the runoff is in Spring Court it will then flow north as
Basin E.1
Basin E.1 is located along the eastern side of the proposed building. Basin E.1 has a
net gardens. area of Runoff 0.04 generated acres and in which Basin is E.associated 1 will sheet with flow concrete west to sidewalks east until and it enters rain one
of hydraulically the two rain as gardens one uniform which rain are garden. connected Once via the a trench runoff drain is treated making within them the act rain
garden chambers it will where enter it will the storm bypass sewer freely and and be release conveyed undetained to the Stormtech into a sidewalk SC-740 chase
located west to within east across Spring the Court. property Any until event it above reaches the the water curb quality and gutter event within will sheet College flow
Avenue. From there the runoff will be conveyed north as historically routed.
Elevations Credit Union
Preliminary Drainage Report 9
Basin R.1
Basin story building R.1 has roof a net runoff. area of Runoff 0.12 created acres and in this is associated basin will exclusively sheet flow with across the the one roof
east the runoff to west into and an enter isolator one row of two containing possible two roof (2) leaders. SC-740 The cells. roof Then, leaders just will like convey Basin
W.1, it will be released into a sidewalk chase located in Spring Court.
Basin OS.1
Basin project OS.site 1 and has consists a net area solely of 0.of 06 landscaping acres and is and located a portion along of the retaining northern wall. edge Runoff of the
generated College Avenue. in Basin The OS.landscaped 1 will overland area will flow act north as a directly water quality offsite undetained measure by into reducing
runoff via infiltration and removing excess sediment.
Basin OS.2
Basin project OS.site. 2 has Basin a net OS.area 2 consists of 0.04 of acres a small and portion is located of the along drive the entrance, eastern pedestrian edge of the
sidewalk, offsite into and College landscaping. Avenue undetained Runoff generated and untreated in Basin just OS.like 2 will historic overland conditions. flow directly Once
in College Avenue it will flow south to north as historically routed.
Basin OS.3
Basin borders OS.of 3 the has project a net area site. Just of 0.15 like acres historic is located patterns, along Basin the OS.western 3 will overland and southern flow
directly OS.3 consists offsite of undetained landscaping, and drive untreated entrance, into Arthur and a portion Drive and of Arthur Spring Drive. Court. Basin
Design Point OS3
Design Point OS3 is associated with Basins W.1, R.1, and OS.3. These three basins
all difference drain west between towards Historic Spring Basin Court W (same and the as combined Historic Basin basins W) draining via overland. to Design The
Point proposing OS3 to is add an increased 4,456 sq. amount ft. of impervious of impervious area area. draining Elevations towards Credit Spring Union Court. is This
area Elevations along Credit with a Union release so rate that of no 0 downstream cfs was used infrastructure to size the required located detention in Spring for Court
will be impacted.
Design Point OS1
Design all sheet Point flow OS1 east is into associated College Avenue with Basins (Same E.as 1, OS.Historic 1, and Basin OS.2. E). These The difference three basins
between Elevations Historic Credit Basin Union E is and reducing Design the Point amount OS1 impervious is the amount associated of impervious with this area. area
by infrastructure 3,346 sq. ft. located Therefore, within Elevations College Avenue. Credit Union will not be impacting any existing
Elevations Credit Union
Preliminary Drainage Report 10
B. Specific Details
1. The existing main stormwater drainage problems infrastructure associated present, with steep this existing project grades, site is the and deficiency FEMA of
floodplains. the same location Currently north the of site the drains site within to the Spring east and Creek. west, The but proposed ultimately site discharges will in
mitigate these issues by instituting the following water quality & detention devices:
Rain Garden along the College Avenue frontage
Stormtech sediment migration. isolator rows The to runoff be wrapped collected with by these a geotextile chambers membrane will then to drain collect
through open graded drainage rock.
Stormtech chambers to release at a restricted rate by use of an orifice plate
The of additional release rate imperviousness for the overall being project proposed site was by established this development. by quantifying The existing the amount
impervious account for area 23,356 accounted sq. ft. for Resulting a total in 22,an 249 overall sq. ft.increase , while in the impervious proposed project area of
1,OS.107 2) is sq. 0.ft. 08 The ac. smaller proposed than area historic routing basin runoff E1 to and the consists east (Basins of 3,346 E.1, sq. OS.ft. 1 and less
impervious and released area undetained. than historic. The proposed Therefore, area flow routing being released runoff to to the the west east (Basins is decreased W.1,
R.more 1 and impervious OS.3) is area 0.08 than ac. larger historic. than To historic ensure basin the peak W1 runoff and consists rate was of decreased, 4,456 sq. ft.
the the detention additional volume impervious was area. based on capturing the entire storm event generated from
2. Detention Pond Calculations
As College previously Avenue, mentioned, while the the area area discharging discharging to the to the west east will will be be detained free released through into
underground the FAA Method detention to detain chambers the entire to account storm event for the generated additional from impervious the additional area. Using
impervious required volume area (will Q = be 0 stored cfs) yields in 19 an Stormtech overall detention SC-740 volume chambers. of 1,The 355 underground cu. ft. This
system located will within discharge Spring Court. through Although a flow control the detention manhole volume towards was a sidewalk calculated chase using a
release Elevations rate Credit of 0 cfs Union. that Using is not actually the characteristics the runoff entering of Basins Spring W.1 and Court R.1 from (Area=0.44
acres, was used Tc=to 5min, calculate C=1.the 00 required and a required release detention and resulted of 1,in 355 a release cu. ft.) rate the of FAA 2.15 Method cfs.
The released 2.15 into cfs Spring runoff from Court Basins from Basin W.1 and OS3 R.results 1 along in with an overall the 0.peak 95 cfs runoff being rate free of
3.cfs. 10 cfs. This proposed rate is 1.76 cfs less than the historic peak runoff rate of 4.86
3. Water Quality Results
Following amenities UDFCD being proposed criteria a with 12-Elevations hour drain Credit time was Union. used Water to size quality all water will quality be provided
as and a R.portion 1. The of isolator the underground rows will be SC-wrapped 740 chambers with a geotextile via isolator membrane rows for Basins to reduce W.1
sediment E.1 will have migration water within quality the provided system via and the improving rain gardens downstream that are hydraulically water quality. Basin
connected via a 4” PVC underdrain.
Elevations Credit Union
Preliminary Drainage Report 11
Basin W.1
Basin isolator W.chambers. 1’s water quality Runoff will will enter be provided the underground via underground system Stormtech through an SC-inlet. 740
Following for Basin W.UDFCD 1. In order standards, to achieve a required this volume WQCV 6 of SC-435.740 60 chambers cu. ft. must must be be provided used to
capture this runoff.
Basin E.1
Basin UDFCD E.BMP 1 will standards have its own a required water quality volume provided of 29.28 via cu. a rain ft. of garden. water quality Following must be
provided 123 cu. ft. for of Basin runoff. E.1. The The rain rain garden garden will has have been a modified designed media to treat section up to underneath a volume of
the pass growing the underground media to promote detention infiltration. system to Once the west the and runoff discharge has been into treated Spring it will Court. bi-
Basin R.1
Basin isolator R.chambers. 1’s water quality Runoff will generated be provided in Basin via R.underground 1 will enter Stormtech the isolator SC-rows 740 via roof
leaders. provided Following for Basin UDFCD R.1. In order criteria, to achieve a required this WQCV volume of 2 139.SC-82 740 cu. chambers ft. must must be be
provided.
4. The by utilizing underground 19 SC-pond 740 will Stormtech provide chambers. enough storage A total for of 1,722.355 20 cu. cu. ft. ft. of of runoff water
quality up to 123.will 00 be cu. provided ft. of runoff onsite and as well. the remaining A rain garden 599.will 20 provide cu. ft. will treatment be treated for
in chambers isolator to rows treat within 599.the 20 SC-cu. 740 ft. of Stormtech runoff. A total chambers. amount It of requires 19 Stormtech 8 SC-740
SC-project 740 for chambers both detention will be and utilized water for quality the proposed purposes. Elevations Credit Union
5. In curb the and case gutter, that the then inlet overtop within the Basin retaining W.1 wall, gets clogged and flow runoff west will into overtop Spring the
Court as it has historically.
Design
Point Basin ID Basin Area Treatment Type
LID
System
Area
Treated by
LID System
Percent of Site
Treated by LID
System
w.1 W.1 0.320 ac. StormTech
Chambers Yes 0.320 ac. 44%
e.1 E.1 0.040 ac. Rain Garden Yes 0.040 ac. 6%
r.1 R.1 0.120 ac. StormTech
Chambers Yes 0.120 ac. 17%
os.1 OS.1 0.050 ac. Grass Buffer No N/A 0%
os.2 OS.2 0.040 ac. Grass Buffer No N/A 0%
os.3 OS.3 0.150 ac. Grass Buffer No N/A 0%
Total 0.720 ac. 0.480 ac. 67%
Elevations Credit Union
Preliminary Drainage Report 12
V. CONCLUSIONS
A. Compliance with Standards
6. The the City drainage of Fort design Collins’ proposed Stormwater with Criteria the Elevations Manual. Credit Union project complies with
7. The the City drainage of Fort design Collins’ proposed Master with Drainage the Elevations Plan for the Credit Spring Union Creek project Basin. complies with
8. The northwest project corner site is of encroached the property. by However, a 100-Year the High development Floodplain will Fringe not be along adversely the
impacting obstruction any of the of the College downstream Avenue bridge. infrastructure, as this floodplain is caused by the
9. The Elevations drainage Credit plan Union and stormwater development management are compliant measures with all proposed applicable with State the and
Federal regulations governing stormwater discharge.
B. Drainage Concept
1. The associated drainage with design its stormwater proposed with runoff. this Elevations project will Credit effectively Union limit will detain potential additional damage
impervious in impervious area area being between routed historic to the and west proposed (4,456 sq. conditions ft.). However, is only the 1,107 total sq. difference ft.
which of Fort is Collins 107 sq. Stormwater ft. above Criteria the maximum Manual. threshold for detention according to the City
2.
Elevations condition to Credit both Union College will Avenue also be and releasing Spring Court at reduced therefore runoffs there from will the be historic no
downstream impacts from this development.
3. Elevations acres) with Credit accepted Union LID will treatments. provide water The remaining quality for portion a majority of the of the project site site (0.48 will
receive quality via water landscaping quality by were crossing uncatchable over landscaped due to steep areas. grades The areas along receiving the north water and
west.
4. The Drainage proposed Plan Elevations recommendations Credit Union for the development Spring Creek will major not impact drainage the basin. Master
Elevations Credit Union
Preliminary Drainage Report 13
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
APPENDIX A
HYDROLOGIC COMPUTATIONS
Elevations Credit Union
CHARACTER OF SURFACE: Runoff
Coefficient
Percentage
Impervious Project: Elevations Credit Union
Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: B. Mathisen
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.
W 22766.0 0.523 0.161 0.185 0.026 0.000 0.000 0.15 0.75 0.75 0.93 67%
E 8600.0 0.197 0.103 0.032 0.005 0.000 0.000 0.06 0.75 0.75 0.93 69%
TOTAL 31366 0.720 0.263 0.217 0.031 0.000 0.000 0.21 0.72 0.72 0.90 67%
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
July 12th, 2016
**Soil Classification of site is Clay Loam**
Page 1 of 20 D:\Projects\207-016\Drainage\Hydrology\207-016_Rational-Calcs(Historic).xlsx\C-Values
Elevations Credit Union
Overland Flow, Time of Concentration:
Project: Elevations Credit Union
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
w W No 0.75 0.75 0.93 68 3.20% 3.7 3.7 1.7 N/A N/A N/A N/A N/A 5 5 5
e E No 0.75 0.75 0.93 50 5.80% 2.6 2.6 1.2 N/A N/A N/A N/A N/A 5 5 5
DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
Elevations Credit Union
Rational Method Equation: Project: Elevations Credit Union
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
w W 0.52 5 5 5 0.75 0.75 0.93 2.85 4.87 9.95 1.11 1.90 4.86
e E 0.20 5 5 5 0.75 0.75 0.93 2.85 4.87 9.95 0.42 0.72 1.83
Intensity,
i10
(in/hr)
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
C10
Area, A
(acres)
Intensity,
i2
(in/hr)
100-yr
Tc
(min)
DEVELOPED RUNOFF COMPUTATIONS
C100
Design
Point
Flow,
Q100
(cfs)
Flow,
Q2
(cfs)
10-yr
Tc
(min)
2-yr
Tc
(min)
C2
Flow,
Q10
(cfs)
Intensity,
i100
(in/hr)
Basin(s)
B. Mathisen
Q C f C i A July 12th, 2016
Page 3 of 20 D:\Projects\207-016\Drainage\Hydrology\207-016_Rational-Calcs(Historic).xlsx\Direct-Runoff
Elevations Credit Union
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C100
2-yr
(min) Tc
100-yr
(min) Tc
(cfs) Q2
(Q100 cfs)
w W 0.52 0.75 0.93 5.0 5.0 1.11 4.86
e E 0.20 0.75 0.93 5.0 5.0 0.42 1.83
Page 4 of 20 D:\Projects\207-016\Drainage\Hydrology\207-016_Rational-Calcs(Historic).xlsx\SUMMARY-TABLE
Elevations Credit Union
CHARACTER OF SURFACE: Runoff
Coefficient
Percentage
Impervious Project: Elevations Credit Union
Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: B. Mathisen
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.
W.1 13939.2 0.320 0.273 0.024 0.000 0.000 0.000 0.02 0.90 0.90 1.00 92%
E.1 1931.3 0.044 0.000 0.028 0.000 0.000 0.000 0.02 0.69 0.69 0.87 57%
R.1 5282.0 0.121 0.000 0.000 0.121 0.00 0.95 0.95 1.00 90%
OS.1 2081.0 0.048 0.000 0.002 0.000 0.000 0.000 0.05 0.28 0.28 0.35 4%
OS.2 1529.0 0.035 0.000 0.033 0.000 0.000 0.000 0.00 0.90 0.90 1.00 84%
OS.3 6600.0 0.152 0.026 0.030 0.000 0.000 0.000 0.10 0.51 0.51 0.63 34%
TOTAL 31363 0.720 0.299 0.116 0.121 0.000 0.000 0.18 0.75 0.75 0.93 71%
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.
Elevations Credit Union
Overland Flow, Time of Concentration:
Project: Elevations Credit Union
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
w.1 W.1 No 0.90 0.90 1.00 89 0.50% 4.5 4.5 2.2 92 3.00% 3.46 0.4 N/A N/A N/A 5 5 5
e.1 E.1 No 0.69 0.69 0.87 21 5.00% 2.0 2.0 1.2 N/A N/A N/A N/A N/A 5 5 5
r.1 R.1 No 0.95 0.95 1.00 45 1.00% 1.9 1.9 1.3 N/A N/A N/A N/A N/A 5 5 5
Elevations Credit Union
Rational Method Equation: Project: Elevations Credit Union
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
w.1 W.1 0.32 5 5 5 0.90 0.90 1.00 2.85 4.87 9.95 0.82 1.40 3.18
e.1 E.1 0.04 5 5 5 0.69 0.69 0.87 2.85 4.87 9.95 0.09 0.15 0.38
r.1 R.1 0.12 5 5 5 0.95 0.95 1.00 2.85 4.87 9.95 0.33 0.56 1.21
os.1 OS.1 0.05 5 5 5 0.28 0.28 0.35 2.85 4.87 9.95 0.04 0.07 0.17
os.2 OS.2 0.04 5 5 5 0.90 0.90 1.00 2.85 4.87 9.95 0.09 0.15 0.35
os.3 OS.3 0.15 5 5 5 0.51 0.51 0.63 2.85 4.87 9.95 0.22 0.37 0.95
DEVELOPED RUNOFF COMPUTATIONS
C100
Design
Point
Flow,
Q100
(cfs)
Flow,
Q2
(cfs)
10-yr
Tc
(min)
2-yr
Tc
(min)
C2
Flow,
Q10
(cfs)
Intensity,
i100
(in/hr)
Basin(s)
B. Mathisen
July 12th,2016
Intensity,
i10
(in/hr)
Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1
C10
Area, A
(acres)
Intensity,
i2
(in/hr)
100-yr
Tc
(min)
Q C f C i A
Page 3 of 23 D:\Projects\207-016\Drainage\Hydrology\207-016_Rational-Calcs(Proposed_final).xlsx\Direct-Runoff
Elevations Credit Union
CHARACTER OF SURFACE: Runoff
Coefficient
Percentage
Impervious Project: Elevations Credit Union
Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: B. Mathisen
Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date: July 12th,2016
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
Design Point Basin IDs Basin Area
(s.f.)
Basin Area
(ac)
Area of
Asphalt
(sq ft)
Area of
Asphalt
(ac)
Area of
Concrete
(sq ft)
Area of
Concrete
(ac)
Area of
Roofs
(sq ft)
Area of
Roofs
(ac)
Area of
Gravel
(sq ft)
Area of
Gravel
(ac)
Area of
Pavers
(sq ft)
Area of
Pavers
(ac)
Area of
Lawns and
Landscaping
(ac)
2-year
Composite Runoff
Coefficient
10-year
Composite Runoff
Coefficient
100-year
Composite Runoff
Elevations Credit Union
Overland Flow, Time of Concentration:
Project: Elevations Credit Union
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
OS OS1, OS2, OS3 No 0.52 0.52 0.65 55 3.50% 5.3 5.3 4.1 N/A N/A N/A N/A 5 5 5
OS3 OS1 W1,R1 & OS3 No 0.88 0.88 1.00 65 2.10% 2.6 2.6 1.2 N/A N/A N/A N/A 5 5 5
OS1, OS2 & E1 No 1.02 1.02 1.00 95 5.20% 0.8 0.8 1.1 N/A N/A N/A N/A 5 5 5
Elevations Credit Union
Rational Method Equation: Project: Elevations Credit Union
Calculations By:
Date:
From Section 3.2.1 of the CFCSDDC
Rainfall Intensity:
OS3 OS OS1, W1,R1 OS2, & OS3 OS3 0.23 5 5 5 0.52 0.52 0.65 2.85 4.87 9.95 0.3 0.6 1.5
OS1 0.59 5 5 5 0.88 0.88 1.00 2.85 4.87 9.95 1.5 2.5 5.9
OS1, OS2 & E1 0.13 5 5 5 1.02 1.02 1.00 2.85 4.87 9.95 0.4 0.6 1.3
Intensity,
(in/i100 hr)
COMBINED DEVELOPED RUNOFF COMPUTATIONS
B. Mathisen
July 12th,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
(min) Tc
10-yr
(min) Tc
100-yr
(min) Tc
Flow,
(cfs) Q2
Flow,
(Q10 cfs)
Flow,
Q100 (cfs)
C2 C10 C100
Intensity,
(in/i2 hr)
Intensity,
(in/i10 hr)
Q C f C i A
Page 6 of 23 D:\Projects\207-016\Drainage\Hydrology\207-016_Rational-Calcs(Proposed_final).xlsx\Comb-Direct-Runoff
Elevations Credit Union
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C100
2-yr
(min) Tc
100-yr
(min) Tc
(cfs) Q2
(Q100 cfs)
w.1 W.1 0.32 0.90 1.00 5.0 5.0 0.82 3.18
e.1 E.1 0.04 0.69 0.87 5.0 5.0 0.09 0.38
r.1 R.1 0.12 0.95 1.00 5.0 5.0 0.33 1.21
os.1 OS.1 0.05 0.28 0.35 5.0 5.0 0.04 0.17
os.2 OS.2 0.04 0.90 1.00 5.0 5.0 0.09 0.35
os.3 OS.3 0.15 0.51 0.63 5.0 5.0 0.22 0.95
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C100
2-yr
(min) Tc
100-yr
(min) Tc
(cfs) Q2
(Q100 cfs)
OS OS1, OS2, OS3 0.23 0.52 0.65 5.3 5.0 0.35 1.51
OS3 W1,R1 & OS3 0.59 0.88 1.00 5.0 5.0 1.48 5.90
OS1 OS1, OS2 & E1 0.13 1.02 1.00 5.0 5.0 0.37 1.27
Page 7 of 23 D:\Projects\207-016\Drainage\Hydrology\207-016_Rational-Calcs(Proposed_final).xlsx\SUMMARY-TABLE
APPENDIX B
HYDRAULIC COMPUTATIONS
B.1 – Storm Sewers
B.2 – Detention Facilities
APPENDIX B.1
STORM SEWERS
APPENDIX B.2
INLETS (FOR FUTURE USE)
APPENDIX B.3
DETENTION FACILITIES
Pond No :
p1
100-yr
1.00
5.00 min 1355 ft3
0.10 acres 0.031 ac-ft
Max Release Rate = 0.00 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 9.950 305 1.00 0.00 0 305
10 7.720 474 0.75 0.00 0 474
15 6.520 600 0.67 0.00 0 600
20 5.600 687 0.63 0.00 0 687
25 4.980 764 0.60 0.00 0 764
30 4.520 832 0.58 0.00 0 832
35 4.080 876 0.57 0.00 0 876
40 3.740 918 0.56 0.00 0 918
45 3.460 956 0.56 0.00 0 956
50 3.230 991 0.55 0.00 0 991
55 3.030 1023 0.55 0.00 0 1023
60 2.860 1053 0.54 0.00 0 1053
65 2.720 1085 0.54 0.00 0 1085
70 2.590 1113 0.54 0.00 0 1113
75 2.480 1142 0.53 0.00 0 1142
80 2.380 1169 0.53 0.00 0 1169
85 2.290 1195 0.53 0.00 0 1195
90 2.210 1221 0.53 0.00 0 1221
95 2.130 1242 0.53 0.00 0 1242
100 2.060 1264 0.53 0.00 0 1264
105 2.000 1289 0.52 0.00 0 1289
110 1.940 1310 0.52 0.00 0 1310
115 1.890 1334 0.52 0.00 0 1334
120 1.840 1355 0.52 0.00 0 1355
*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
207-016
Pond No :
p1
100-yr
1.00
5.00 min 1355 ft3
0.44 acres 0.031 ac-ft
Max Release Rate = 2.15 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 1313 1.00 2.15 644 669
10 7.720 2038 0.75 1.61 966 1072
15 6.520 2582 0.67 1.43 1288 1294
20 5.600 2957 0.63 1.34 1610 1347
25 4.980 3287 0.60 1.29 1932 1355
30 4.520 3580 0.58 1.25 2254 1326
35 4.080 3770 0.57 1.23 2576 1194
40 3.740 3949 0.56 1.21 2898 1052
45 3.460 4110 0.56 1.19 3220 891
50 3.230 4264 0.55 1.18 3542 722
55 3.030 4400 0.55 1.17 3864 536
60 2.860 4530 0.54 1.16 4186 345
65 2.720 4668 0.54 1.16 4508 160
70 2.590 4786 0.54 1.15 4830 -43
75 2.480 4910 0.53 1.14 5151 -241
80 2.380 5027 0.53 1.14 5473 -447
85 2.290 5139 0.53 1.14 5795 -657
90 2.210 5251 0.53 1.13 6117 -866
95 2.130 5342 0.53 1.13 6439 -1097
100 2.060 5438 0.53 1.13 6761 -1323
105 2.000 5544 0.52 1.12 7083 -1539
110 1.940 5634 0.52 1.12 7405 -1771
115 1.890 5738 0.52 1.12 7727 -1989
120 1.840 5829 0.52 1.12 8049 -2220
*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
207-016
Elevations Credit Union
Project Number :
Project Name :
Underground Pond - Release Rate
A =
Tc =
APPENDIX C
WATER QUALITY DESIGN COMPUTATIONS
Project Tittle Date:
Project Number Calcs By:
Client
Pond Designation
0.8
WQCV = Watershed inches of Runoff (inches) 92.00%
a = Runoff Volume Reduction (constant)
i = Total imperviouness Ratio (i = Iwq/100) 0.335 in
A = 0.44 ac
V = 0.01 ac-ft
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
1.2 = 20% Additional Volume (Sediment Accumulation)
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
Elevations Credit Union July 8th, 2016
207-016 B. Mathisen
Underground Pond - Basin W.1
0.335
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 Tittle 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 imperviouness Ratio (i = Iwq/100) 0.321 in
A = 0.12 ac
V = 0.00 ac-ft -->=139.82 cu. ft.
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
1.2 = 20% Additional Volume (Sediment Accumulation)
Elevations Credit Union July 8th, 2016
207-016 B. Mathisen
Underground Pond - Basin R.1
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
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
2257 cu. ft.
SC-740
31
74.9 cu. ft.
575.42 cu. ft.
8
599.2 cu. ft.
* 2 chambers required for Basin R.1 = 149.80 cu. ft.
* 6 chambers required for Basin W.1 = 449.40 cu. ft.
Number of chambers required for WQ=
Total WQCV acquired=
FAA Modified Required Detention =
StormTech chambers used =
Number of chambers required=
Volume of a single chamber=
Required Water Quality within chambers=
Project Tittle Date:
Project Number Calcs By:
Client
Pond Designation
0.8
WQCV = Watershed inches of Runoff (inches) 57.00%
a = Runoff Volume Reduction (constant)
i = Total imperviouness Ratio (i = Iwq/100) 0.181 in
A = 0.04 ac
V = 0.00 ac-ft --> = 26.28 cu.ft.
V = Water Quality Design Volume (ac-ft)
WQCV = Water Quality Capture Volume (inches)
A = Watershed Area (acres)
Elevations Credit Union July 8th, 2016
207-016 B. Mathisen
Rain Garden - Basin E.1
Drain Time
a =
i =
WQCV =
Figure EDB-2 - Water Quality Capture Volume (WQCV), 80th Percentile Runoff Event
0.181
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
12 hr
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 57.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.570
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.18 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 1,931 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 = 29.2 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 = 6 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 2.00 ft / ft Z < 4:1
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin = 19 sq ft
D) Actual Flat Surface Area AActual = 201 sq ft
E) Area at Design Depth (Top Surface Area) ATop = 289 sq ft
F) Rain Garden Total Volume VT= 123 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 = 0.5 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = 29 cu ft
iii) Orifice Diameter, 3/8" Minimum DO = 0.17 in MINIMUM DIAMETER = 3/8"
Design Procedure Form: Rain Garden (RG)
B. Mathisen
Northern Engineering
July 8, 2016
Elevations Credit Union
Fort Collins - CO - Basin E.1
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
RainGardens_BMP.xlsm, RG 7/8/2016, 1:47 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)
B. Mathisen
Northern Engineering
July 8, 2016
Elevations Credit Union
Fort Collins - CO - Basin E.1
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
RainGardens_BMP.xlsm, RG 7/8/2016, 1:47 PM
APPENDIX D
EROSION CONTROL REPORT
Elevations Credit Union
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,
APPENDIX E
Soils Resource Report
United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Larimer County
Natural Area, Colorado
Resources
Conservation
Service
July 1, 2016
Preface
Soil surveys contain information that affects land use planning in survey areas. They
highlight soil limitations that affect various land uses and provide information about
the properties of the soils in the survey areas. Soil surveys are designed for many
different users, including farmers, ranchers, foresters, agronomists, urban planners,
community officials, engineers, developers, builders, and home buyers. Also,
conservationists, teachers, students, and specialists in recreation, waste disposal,
and pollution control can use the surveys to help them understand, protect, or enhance
the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil properties
that are used in making various land use or land treatment decisions. The information
is intended to help the land users identify and reduce the effects of soil limitations on
various land uses. The landowner or user is responsible for identifying and complying
with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some cases.
Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/portal/
nrcs/main/soils/health/) and certain conservation and engineering applications. For
more detailed information, contact your local USDA Service Center (http://
offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic
tank absorption fields. A high water table makes a soil poorly suited to basements or
underground installations.
The National Cooperative Soil Survey is a joint effort of the United States Department
of Agriculture and other Federal agencies, State agencies including the Agricultural
Experiment Stations, and local agencies. The Natural Resources Conservation
Service (NRCS) has leadership for the Federal part of the National Cooperative Soil
Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs
and activities on the basis of race, color, national origin, age, disability, and where
applicable, sex, marital status, familial status, parental status, religion, sexual
orientation, genetic information, political beliefs, reprisal, or because all or a part of an
individual's income is derived from any public assistance program. (Not all prohibited
bases apply to all programs.) Persons with disabilities who require alternative means
2
for communication of program information (Braille, large print, audiotape, etc.) should
contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a
complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400
Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272
(voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and
employer.
3
Contents
Preface....................................................................................................................2
How Soil Surveys Are Made..................................................................................5
Soil Map..................................................................................................................7
Soil Map................................................................................................................8
Legend..................................................................................................................9
Map Unit Legend................................................................................................10
Map Unit Descriptions........................................................................................10
Larimer County Area, Colorado......................................................................12
3—Altvan-Satanta loams, 0 to 3 percent slopes.........................................12
References............................................................................................................14
4
How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous areas
in a specific area. They include a description of the soils and miscellaneous areas and
their location on the landscape and tables that show soil properties and limitations
affecting various uses. Soil scientists observed the steepness, length, and shape of
the slopes; the general pattern of drainage; the kinds of crops and native plants; and
the kinds of bedrock. They observed and described many soil profiles. A soil profile is
the sequence of natural layers, or horizons, in a soil. The profile extends from the
surface down into the unconsolidated material in which the soil formed or from the
surface down to bedrock. The unconsolidated material is devoid of roots and other
living organisms and has not been changed by other biological activity.
Currently, soils are mapped according to the boundaries of major land resource areas
(MLRAs). MLRAs are geographically associated land resource units that share
common characteristics related to physiography, geology, climate, water resources,
soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically
consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that is
related to the geology, landforms, relief, climate, and natural vegetation of the area.
Each kind of soil and miscellaneous area is associated with a particular kind of
landform or with a segment of the landform. By observing the soils and miscellaneous
areas in the survey area and relating their position to specific segments of the
landform, a soil scientist develops a concept, or model, of how they were formed. Thus,
during mapping, this model enables the soil scientist to predict with a considerable
degree of accuracy the kind of soil or miscellaneous area at a specific location on the
landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented by
an understanding of the soil-vegetation-landscape relationship, are sufficient to verify
predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them to
identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character of
soil properties and the arrangement of horizons within the profile. After the soil
scientists classified and named the soils in the survey area, they compared the
5
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that have
similar use and management requirements. Each map unit is defined by a unique
combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components of
the map unit. The presence of minor components in a map unit in no way diminishes
the usefulness or accuracy of the data. The delineation of such landforms and
landform segments on the map provides sufficient information for the development of
resource plans. If intensive use of small areas is planned, onsite investigation is
needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape, and
experience of the soil scientist. Observations are made to test and refine the soil-
landscape model and predictions and to verify the classification of the soils at specific
locations. Once the soil-landscape model is refined, a significantly smaller number of
measurements of individual soil properties are made and recorded. These
measurements may include field measurements, such as those for color, depth to
bedrock, and texture, and laboratory measurements, such as those for content of
sand, silt, clay, salt, and other components. Properties of each soil typically vary from
one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists interpret
the data from these analyses and tests as well as the field-observed characteristics
and the soil properties to determine the expected behavior of the soils under different
uses. Interpretations for all of the soils are field tested through observation of the soils
in different uses and under different levels of management. Some interpretations are
modified to fit local conditions, and some new interpretations are developed to meet
local needs. Data are assembled from other sources, such as research information,
production records, and field experience of specialists. For example, data on crop
yields under defined levels of management are assembled from farm records and from
field or plot experiments on the same kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on such
variables as climate and biological activity. Soil conditions are predictable over long
periods of time, but they are not predictable from year to year. For example, soil
scientists can predict with a fairly high degree of accuracy that a given soil will have
a high water table within certain depths in most years, but they cannot predict that a
high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
identified each as a specific map unit. Aerial photographs show trees, buildings, fields,
roads, and rivers, all of which help in locating boundaries accurately.
Custom Soil Resource Report
6
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of soil
map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
7
8
Custom Soil Resource Report
Soil Map
4490030 4490040 4490050 4490060 4490070 4490080
4490030 4490040 4490050 4490060 4490070 4490080
493400 493410 493420 493430 493440 493450 493460 493470 493480
493400 493410 493420 493430 493440 493450 493460 493470 493480
40° 33' 41'' N
105° 4' 41'' W
40° 33' 41'' N
105° 4' 36'' W
40° 33' 39'' N
105° 4' 41'' W
40° 33' 39'' N
105° 4' 36'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 20 40 80 120
Feet
0 5 10 20 30
Meters
Map Scale: 1:443 if printed on A landscape (11" x 8.5") sheet.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
Map Unit Legend
Larimer County Area, Colorado (CO644)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
3 Altvan-Satanta loams, 0 to 3
percent slopes
0.8 100.0%
Totals for Area of Interest 0.8 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the soils
or miscellaneous areas in the survey area. The map unit descriptions, along with the
maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the landscape,
however, the soils are natural phenomena, and they have the characteristic variability
of all natural phenomena. Thus, the range of some observed properties may extend
beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic
class rarely, if ever, can be mapped without including areas of other taxonomic
classes. Consequently, every map unit is made up of the soils or miscellaneous areas
for which it is named and some minor components that belong to taxonomic classes
other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They generally
are in small areas and could not be mapped separately because of the scale used.
Some small areas of strongly contrasting soils or miscellaneous areas are identified
by a special symbol on the maps. If included in the database for a given area, the
contrasting minor components are identified in the map unit descriptions along with
some characteristics of each. A few areas of minor components may not have been
observed, and consequently they are not mentioned in the descriptions, especially
where the pattern was so complex that it was impractical to make enough observations
to identify all the soils and miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the usefulness
or accuracy of the data. The objective of mapping is not to delineate pure taxonomic
classes but rather to separate the landscape into landforms or landform segments that
have similar use and management requirements. The delineation of such segments
on the map provides sufficient information for the development of resource plans. If
intensive use of small areas is planned, however, onsite investigation is needed to
define and locate the soils and miscellaneous areas.
Custom Soil Resource Report
10
An identifying symbol precedes the map unit name in the map unit descriptions. Each
description includes general facts about the unit and gives important soil properties
and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major horizons
that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity,
degree of erosion, and other characteristics that affect their use. On the basis of such
differences, a soil series is divided into soil phases. Most of the areas shown on the
detailed soil maps are phases of soil series. The name of a soil phase commonly
indicates a feature that affects use or management. For example, Alpha silt loam, 0
to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps. The
pattern and proportion of the soils or miscellaneous areas are somewhat similar in all
areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present or
anticipated uses of the map units in the survey area, it was not considered practical
or necessary to map the soils or miscellaneous areas separately. The pattern and
relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-
Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas that
could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion of
the soils or miscellaneous areas in a mapped area are not uniform. An area can be
made up of only one of the major soils or miscellaneous areas, or it can be made up
of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil material
and support little or no vegetation. Rock outcrop is an example.
Custom Soil Resource Report
11
Larimer County Area, Colorado
3—Altvan-Satanta loams, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: jpw2
Elevation: 5,200 to 6,200 feet
Mean annual precipitation: 13 to 15 inches
Mean annual air temperature: 48 to 50 degrees F
Frost-free period: 135 to 150 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Altvan and similar soils: 45 percent
Satanta and similar soils: 30 percent
Minor components: 25 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Altvan
Setting
Landform: Benches, terraces
Landform position (three-dimensional): Side slope, tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Mixed alluvium
Typical profile
H1 - 0 to 10 inches: loam
H2 - 10 to 18 inches: clay loam, loam, sandy clay loam
H2 - 10 to 18 inches: loam, fine sandy loam, silt loam
H2 - 10 to 18 inches: gravelly sand, gravelly coarse sand, coarse sand
H3 - 18 to 30 inches:
H3 - 18 to 30 inches:
H3 - 18 to 30 inches:
H4 - 30 to 60 inches:
H4 - 30 to 60 inches:
H4 - 30 to 60 inches:
Properties and qualities
Slope: 0 to 3 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 10 percent
Available water storage in profile: Very high (about 13.2 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 3e
Custom Soil Resource Report
12
Hydrologic Soil Group: B
Description of Satanta
Setting
Landform: Structural benches, terraces
Landform position (three-dimensional): Side slope, tread
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Mixed alluvium and/or eolian deposits
Typical profile
H1 - 0 to 9 inches: loam
H2 - 9 to 18 inches: loam, clay loam, sandy clay loam
H2 - 9 to 18 inches: loam, clay loam, fine sandy loam
H2 - 9 to 18 inches:
H3 - 18 to 60 inches:
H3 - 18 to 60 inches:
H3 - 18 to 60 inches:
Properties and qualities
Slope: 0 to 1 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 10 percent
Available water storage in profile: Very high (about 27.4 inches)
Interpretive groups
Land capability classification (irrigated): 1
Land capability classification (nonirrigated): 3c
Hydrologic Soil Group: B
Minor Components
Nunn
Percent of map unit: 10 percent
Larim
Percent of map unit: 10 percent
Stoneham
Percent of map unit: 5 percent
Custom Soil Resource Report
13
References
American Association of State Highway and Transportation Officials (AASHTO). 2004.
Standard specifications for transportation materials and methods of sampling and
testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service
FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils
in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S.
Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/soils/?cid=nrcs142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making
and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service,
U.S. Department of Agriculture Handbook 436. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://www.nrcs.usda.gov/wps/
portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
home/?cid=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
14
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States, the
Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.
http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
Custom Soil Resource Report
15
MAP POCKET
HISTORIC DRAINAGE EXHIBIT
PROPOSED DRAINAGE EXHIBIT
CONTROL
CONTROL IRR
IRR
S
S
CONTROL
IRR
CONTROL
IRR
W
W
W
W
W
W
W
W
W W W W
G
G
G
G
G
G
G
G
G
G
G
G
G
G
G
E E
E E E E E
G
G
G G G
G G
G
G
G
G
G G G
G
G G
G
G
G G
G
G
G
G
G G
G
G
G
G
X
X
CONTROL
CONTROL IRR
IRR
S
S
CONTROL
IRR
CONTROL
IRR
X
X
X
X
X
X X X
X
E
W
EXISTING SIDEWALK
CHASE
COLLEGE AVENUE
ARTHUR DRIVE
SPRING COURT
EXISTING CONCRETE PAN
w e
EXISTING INLET
12" PVC
FL=4988.38
EASEMENT FOR SIDEWALK
AND ELECTRICAL ACCESS PER
REC. NO. 87041080
EASEMENT FOR WATERLINE
PER BOOK 988, PAGE 351
AND BOOK 1394, PAGE 760
EXISTING 100-YR
FEMA FLOODPLAIN
FEMA REGULATED
FLOOD FRINGE
FEMA REGULATED
FLOOD FRINGE
EASEMENT FOR WATER
LINE REC. NO. 87041081
EASEMENT FOR UNDERGROUND
ELECTRIC LINE PER REC. NO. 87041082
4" PVC
FL=4993.69
4" PVC
FL=4993.43
EASEMENT FOR SANITARY
MANHOLE PER REC. NO. 87041083
EXISTING CONCRETE CHASE
Sheet
of 7 Sheets
ELEVATIONS CREDIT UNION
DRAWING FILENAME: D:\Projects\207-016\Dwg\Drng\207-016_EX_DRNG.dwg LAYOUT NAME: C401 DATE: Jul 12, 2016 - 11:46am CAD OPERATOR: blaine
LIST OF XREFS: [207-016_xTopo] [207-016_xExist] [NES-xborder]
These drawings are
instruments of service
provided by Northern
Engineering Services, Inc.
and are not to be used for
any type of construction
unless signed and sealed by
a Professional Engineer in
the employ of Northern
Engineering Services, Inc.
NOT FOR CONSTRUCTION
REVIEW SET
ENGINEER ING
N O R T H E RN
7.12.16
301 North Howes Street, Suite 100
Fort Collins, Colorado 80521
www.northernengineering.com
Phone: 970.221.4158
NORTH
( IN FEET )
1 inch = ft.
10 0 10 Feet
10
20 30
NORTH
CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU
DIG, GRADE, OR EXCAVATE FOR THE MARKING OF
UNDERGROUND MEMBER UTILITIES.
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what'sbelow.
Call before you dig.
R
ST
A2
a3
4950
4:1
79.45
HP
RUNOFF SUMMARY TABLE:
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
NOTES:
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C100
2-yr
Tc
(min)
100-yr
Tc
(min)
Q2
(cfs)
Q100
(cfs)
w W 0.52 0.75 0.93 5.0 5.0 1.11 4.86
e E 0.20 0.75 0.93 5.0 5.0 0.42 1.83
NORTH
( IN FEET )
1 inch = ft.
10 0 10 Feet
10
20 30
NORTH
CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU
DIG, GRADE, OR EXCAVATE FOR THE MARKING OF
UNDERGROUND MEMBER UTILITIES.
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what'sbelow.
Call before you dig.
R
C401
EXISTING DRAINAGE PLAN
LEGEND:
ST
A2
a3
4950
4:1
79.45
HP
RUNOFF SUMMARY TABLE:
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
NOTES:
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C100
2-yr
Tc
(min)
100-yr
Tc
(min)
Q2
(cfs)
Q100
(cfs)
w W 0.52 0.75 0.93 5.0 5.0 1.11 4.86
e E 0.20 0.75 0.93 5.0 5.0 0.42 1.83
7
X X
X
X
W
W
W
W W W
G
G
G
G
G
G
G
G
G G
SS
SS
SS SS SS
SS SS
SS SS
SS SS
SS
SS
SS SS
SS
SS SS
SS
SS
SS SS
SS
SS
SS
SS
SS SS SS SS SS SS
S
G
G
EV
E E
E E E E E E
RD
RD
UD UD
UD UD UD UD
1" W
1" W
1" W
1" W
1" W
1" W
1" W
W
E
E
W.1
OS.1
E.1
OS.2
OS.3
os.1
COLLEGE AVENUE
ARTHUR DRIVE
SPRING COURT
os.3
ISOLATOR ROW
ISOLATOR ROW
INLET U1
RAIN GARDEN
RAIN GARDEN
FLOW CONTROL
MANHOLE
19 SC-740
STORMTECH
CHAMBERS
EXISTING 100-YR
FEMA FLOODPLAIN
EXISTING 100-YR
FEMA FLOODPLAIN
PROPOSED
RETAINING
WALL
FEMA REGULATED
FLOOD FRINGE
FEMA REGULATED
FLOOD FRINGE
OVERFLOW GRATE
CURB CHAASE
8:1
9:1
62:1
23:1
17:1
25:1
8:1
14:1
10:1
10:1
15:1
OUTFALL
TRASH ENCLOSURE
RETAINING WALL
RETAINING WALL
FFE=95.35
TRENCH DRAIN
PROPOSED SIDEWALK
PROPOSED SIDEWALK
PROPOSED SIDEWALK
PROPOSED SIDEWALK
EXISTING SIDEWALK
RECONSTRUCTED SIDEWALK
PROPOSED SIDEWALK
PROPOSED
PARKING LOT
R.1
CONCRETE CHASE
SIDEWALK CHASE
ISOLATOR ROW
Sheet
of 7 Sheets
ELEVATIONS CREDIT UNION
DRAWING FILENAME: D:\Projects\207-016\Dwg\Drng\207-016_DRNG.dwg LAYOUT NAME: C400 DATE: Jul 12, 2016 - 11:46am CAD OPERATOR: blaine
LIST OF XREFS: [207-016_xExist] [207-016_xSite] [207-016_xPutil] [207-016_xPgrad] [NES-xborder]
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
E NGINEER ING
N O R T H E RN
7.12.16
301 North Howes Street, Suite 100
Fort Collins, Colorado 80521
www.northernengineering.com
Phone: 970.221.4158
NORTH
( IN FEET )
1 inch = ft.
10 0 10 Feet
10
20 30
NORTH
CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU
DIG, GRADE, OR EXCAVATE FOR THE MARKING OF
UNDERGROUND MEMBER UTILITIES.
CALL UTILITY NOTIFICATION CENTER OF
COLORADO
Know what'sbelow.
Call before you dig.
R
C400
DRAINAGE PLAN
LEGEND:
ST
A2
a3
4950
4:1
79.45
HP
RUNOFF SUMMARY TABLE:
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
NOTES:
DESIGN
POINT
BASIN
ID
TOTAL
AREA
(acres)
C2 C100
2-yr
Tc
(min)
100-yr
Tc
(min)
Q2
(cfs)
Q100
(cfs)
w.1 W.1 0.32 0.90 1.00 5.0 5.0 0.82 3.16
e.1 E.1 0.04 0.69 0.87 5.0 5.0 0.09 0.38
r.1 R.1 0.12 0.95 1.00 5.0 5.0 0.33 1.21
os.1 OS.1 0.06 0.28 0.35 5.0 5.0 0.04 0.19
os.2 OS.2 0.03 0.91 1.00 5.0 5.0 0.09 0.35
os.3 OS.3 0.15 0.52 0.64 5.0 5.0 0.21 0.93
6
the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 10, Sep 22, 2015
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Apr 22, 2011—Apr 28,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Custom Soil Resource Report
9
12 hr
12 hr
Project Location :
Design Point
C =
Design Storm
Page 1 of 1
207-016_DetentionVolume_FAAModified Method - Find Release.xls
Elevations Credit Union
Project Number :
Project Name :
Underground Pond - Detention
Page 1 of 1
207-016_DetentionVolume_FAAModified Method - Zero Release.xls
COMBINED DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
B. Mathisen
July 12th,2016
Design
Point Basin IDs
Overland Flow Gutter/Pipe Flow Swale Flow Time of Concentration
(Equation RO-4)
1 3
1 . 87 1 . 1 *
S
Ti C Cf L
Page 5 of 23 D:\Projects\207-016\Drainage\Hydrology\207-016_Rational-Calcs(Proposed_final).xlsx\Comb-Tc-10-yr_&_100-yr
Coefficient
Composite
% Imperv.
OS OS1, OS2, OS3 10210 0.23 1113.76 0.03 2808.42 0.06 0.00 0.00 0.00 0.00 0.00 0.00 0.14 0.52 0.52 0.65 36%
OS3 W1,R1 & OS3 25821 0.59 13005.26 0.30 2331.15 0.05 5282.39 0.12 0.00 0.00 0.00 0.00 0.28 0.88 0.88 1.00 77%
OS1 OS1, OS2 & E1 5541 0.13 0.00 0.00 2737.52 0.06 0.00 0.00 0.00 0.00 0.00 0.00 0.28 1.02 1.02 1.00 44%
COMBINED DEVELOPED COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS
**Soil Classification of site is Sandy 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.
Page 4 of 23 D:\Projects\207-016\Drainage\Hydrology\207-016_Rational-Calcs(Proposed_final).xlsx\Comb-C-Values
os.1 OS.1 No 0.28 0.28 0.35 29 25.20% 2.8 2.8 2.6 N/A N/A N/A N/A N/A 5 5 5
os.2 OS.2 No 0.90 0.90 1.00 32 4.90% 1.2 1.2 0.6 N/A N/A N/A N/A N/A 5 5 5
os.3 OS.3 No 0.51 0.51 0.63 43 13.80% 3.0 3.0 2.4 N/A N/A N/A N/A N/A 5 5 5
DEVELOPED TIME OF CONCENTRATION COMPUTATIONS
Gutter/Pipe Flow Swale Flow
Design
Point Basin
Overland Flow
B. Mathisen
July 12th,2016
Time of Concentration
(Equation RO-4)
1 3
1 . 87 1 . 1 *
S
Ti C Cf L
Page 2 of 23 D:\Projects\207-016\Drainage\Hydrology\207-016_Rational-Calcs(Proposed_final).xlsx\Tc-10-yr_&_100-yr
10-year Cf = 1.00
July 12th,2016
**Soil Classification of site is Clay Loam**
Page 1 of 23 D:\Projects\207-016\Drainage\Hydrology\207-016_Rational-Calcs(Proposed_final).xlsx\C-Values
Gutter/Pipe Flow Swale Flow
Design
Point Basin
Overland Flow
B. Mathisen
July 12th, 2016
Time of Concentration
(Equation RO-4)
1 3
1 . 87 1 . 1 *
S
Ti C Cf L
Page 2 of 20 D:\Projects\207-016\Drainage\Hydrology\207-016_Rational-Calcs(Historic).xlsx\Tc-10-yr_&_100-yr