South Santa Fe PD Phase 1 Drainage Report · plan of the historical drainage basin is included in...

PHASE I DRAINAGE REPORT

FOR

CONIFER COMMONS

January 27, 2020

Prepared for: PWN Architects and Planners, Inc.

4949 S. Syracuse St., Suite 320 Denver, Colorado 80237

Prepared by:

1120 Lincoln Street, Suite 1000

Denver, CO 80203 Ph: 303-623-6300, Fax: 303-623-6311

Mark A. West, P.E., CFM

Harris Kocher Smith Project No. 200115

TABLE OF CONTENTS

II. General Location and Description ............................................................................ 2

A. Location .................................................................................................................... 2 B. Description of Property ............................................................................................. 2 C. Existing Facilities and Historical Flows ..................................................................... 3

III. Major/Minor Drainage Basin ..................................................................................... 3 A. Major Basin Description ............................................................................................ 3

B. Sub-Basin Description .............................................................................................. 4 IV. Drainage Design Criteria .......................................................................................... 5

A. Regulations............................................................................................................... 5

B. Development Criteria Reference Constraints ........................................................... 5 C. Hydrologic Criteria .................................................................................................... 6 D. Hydraulic Criteria ...................................................................................................... 7

E. Stormwater Quality/Sediment Erosion Control ......................................................... 7 F. Modifications of Criteria ............................................................................................ 9

V. Drainage Facility Design ........................................................................................... 9

A. General Concept ...................................................................................................... 9 B. Specific Details ....................................................................................................... 10

VI. CONCLUSIONS ..................................................................................................... 10 A. Compliance with Standards .................................................................................... 10 B. Drainage Concept ................................................................................................... 11

VII. REFERENCES ....................................................................................................... 12

APPENDIX A – ALTA, FIRM MAP

APPENDIX B – SOILS SURVEY

APPENDIX C – SITE SUB-BASIN RATIONAL CALCULATIONS

APPENDIX D – MAJOR BASIN CUHP CALCULATIONS

APPENDIX E – WATER QUALITY AND DETENTION POND CALCULATIONS

APPENDIX F – SITE DRAINAGE PLAN

APPENDIX G – MAJOR BASIN DRAINAGE PLAN

1

I. Engineers Certification

This report for the drainage design of Conifer Commons was prepared by me (or under my

supervision) in accordance with the provisions of Jefferson County Storm Drainage Design

and Technical Criteria, and was designed to comply with the provisions thereof. I

understand that the County of Jefferson does not, and will not, assume liability for drainage

facilities designed by others.

_________________________________________________________________

Mark A. West, P.E., C.F.M.

State of Colorado Registration No. 38561

On behalf of Harris Kocher Smith

2

II. General Location and Description

A. Location

The proposed Conifer Commons project (hereinafter referred to as “Site”) is located in the

Southwest quarter of Section 13 and the Southeast quarter of Section 14, Township 6

South, Range 71 West of the 6th Principle Meridian, County of Jefferson, State of

Colorado. The property is comprised of approximately 47.12 acres of undeveloped land,

of which 16.39 acres will be developed with this project. The Site is bounded by a

shopping center to the North, a channel to the East, Pleasant Park Rd to the South, and

US Highway 285 to the West.

According to an ALTA Title Commitment prepared by Baseline, dated August 31, 2018, the

Site. An ingress egress easement (Book 2611 at page 911) exists within the Southeast

corner of the property. The ALTA for the site is included in Appendix A.

B. Description of Property

The Site is currently comprised of an undeveloped parcel. The 16.39-acre site is

undeveloped and consists of wooded areas and native grasses and weeds with some

sparse trees and shrubs.

The majority of the existing Site generally slopes from a highpoint in the Southwest corner

of the Site to Northeast at grades of 13% to 20% and has a total fall of approximately 140

to 150 feet. The proposed site grading will have general slopes of 2% to 6% from a

highpoint along the Western portion of the site towards the Northern end of the site.

The Site is shown to be Zone X (unshaded) Flood Area according to FIRM Map

08059C0370F, Jefferson County, Colorado, and dated effective February 5, 2014. Zone X

3

(unshaded) is described in this map as determined to be as areas of 0.2% annual chance

flood; areas of 1% annual chance flood with average depths of less than 1 foot or with

drainage areas less than 1 square mile; and areas protected by levees from 1% annual

chance flood of minimal flood hazard. A copy of the Site FIRMette map is in Appendix A.

According to the Soil Conservation Service’s Soil Survey for the Golden Area, the soils are

predominately Grimstone-Hiwan-Rock outcrop complex, 30 to 60 percent slopes (55),

Legault-Hiwan stony loamy sands, 15 to 30 percent slopes (76), and Venable loam, 3 to 9

percent slopes (171). The entire site is therefore comprised of SCS hydrologic soil groups

C & D and exhibit a moderately high runoff potential and low infiltration rate. A copy of the

Soil Survey is included in Appendix B.

C. Existing Facilities and Historical Flows

The property primarily consists of predeveloped area. Flows would historically run from

southwest to northeast across the property to a low point that runs north parallel with the

property and ultimately to North Turkey Creek. There is one 30” CMP that is shown on the

ALTA, running beneath the asphalt entrance on the western side of the property.

III. Major/Minor Drainage Basin

A. Major Basin Description

The existing major drainage basin is comprised of approximately 297.5 acres of primarily

undeveloped land consisting of wooded areas and native grasses and weeds with some

sparse trees and shrubs. The majority of the major drainage basin contains steep terrain

and slopes from a highpoint in the southwest to the northeast at grades of 13% to 20% and

has a total fall of approximately 500 to 800 feet. The Site and the major drainage basin lie

along an unnamed tributary within the upper portion of basin that is tributary to North

Turkey Creek downstream of the Site.

4

The major basin was delineated into one 297.5 acre basin with a design point in the

channel just downstream from the site. The major basin consists of highpoints to the East,

South, and West of the channel. See basin calculations in Appendix D and plan in

Appendix G. Due to the size of the basin Colorado’s Urban Hydrograph Procedure (CUHP)

was required and was used to find pre and post peak 100-year flows of 444.40 CFS and

455.84 CFS respectively.

For further reference, a plan detailing the major drainage basin is included in Appendix G,

and basin calculations are included in Appendix D.

B. Sub-Basin Description

Historically the Site consisted of one basin A-1 historic. Runoff would sheet flow southeast

to northwest across the site to the Channel on the northern end of the property. The

channel conveyed flows north beneath US 285 and ultimately to North Turkey Creek. The

calculated percent imperviousness of the historical site is 1.5%. For further reference, a

plan of the historical drainage basin is included in Appendix G, and basin calculations are

included in Appendix C.

For the proposed development the site was delineated into 1 sub-basin, A-1 developed, for

the purpose of this Report and is shown on Final Drainage Plan (see Appendix F) and

further described below.

Basin A-1 (16.39 acres) is located in the central portion of the parcel and will consist of

roof area, sidewalk, landscape area and roads. All Runoff from this basin is routed

towards the proposed full spectrum detention pond at Design Point 1 (DP-1).

5

IV. Drainage Design Criteria

A. Regulations

This report has been prepared in accordance with the following criteria.

1. Jefferson County Colorado (SDDTC) Storm Drainage & Technical Criteria Revised

June 01, 2019.

2. Urban Drainage and Flood Control District’s (MHFD) Urban Storm Drainage Criteria

Manual, Vol. 1 Revised August 2018.


Manual, Vol. 2 Revised September 2017


Manual, Vol. 3 Revised October 2019,

B. Development Criteria Reference Constraints

Historically the runoff from the site is conveyed un-detained and directly discharging to the

unnamed tributary to North Turkey Creek. The developed site will produce a higher runoff

volume due to increased imperviousness, and this runoff will be detained to (or below)

existing runoff rates through the addition of storm sewer and the on-site full spectrum

detention pond. Detailed Hydrologic calculations can be found in Appendix C and

Detention Calculations can be found in Appendix E.

Off – Site Flows:

Historically the Site experiences off-site flows from a highpoint west and south west of the

site. The proposed site will convey these offsite flows overland through the site. With the

final report a hydraulic analysis of the site will verify that no proposed buildings would be

inundated and that the water surface elevations of the flow through the Site are below the

finished floor elevations of any proposed structures.

6

C. Hydrologic Criteria

The method used to calculate runoff and analyze the hydrology of the site was the Rational

Method. The 5-year storm event was used as the minor storm and the 100-year storm

event was used as the major storm. One-hour point rainfall values were obtained from

Table 501 of the Jefferson County’s SDDTC for Jefferson IIB County Zone. The values

listed in Table 501 were obtained from NOAA Atlas 14.

One hours point rainfall data for the Site is listed below:

One Hour Rainfall (in.)

5-Year 100-Year

1.19 2.20

The following formula, from the MHFD Criterial Manual, was used to determine rainfall

intensities:

- USDCM Volume 1, Equation 5-1

Runoff “C” coefficients were determined using equations for soil type C/D in table 6-4

MHFD Criteria Manual Volume 1 by determining the percent imperviousness of each sub

basin based on values outlined in Table 6-3. Details of the Rational Method Calculations

are included in Appendix C & D

7

D. Hydraulic Criteria

Final details on the hydraulic design will be included with the Phase III drainage report.

The Hydraulic Capacity for the proposed storm sewer system will be designed in

accordance with MHFD Criteria Manual Volume 1, Chapter 7.

Flows will be directed to the proposed full spectrum Detention Pond by storm sewer

system or via surface drainage and roadside ditches.

As needed, inlet capacities for the 5-year and 100-year events will be analyzed using UD-

Inlet v4.05 (March 2017) assuming a clogged inlet condition. The Hydraulic Grade Line

(HGL) and head loss in the proposed storm sewer system will be designed in accordance

with the MHFD Criteria Manual Volume 1, 2 and 3.

The minimum and maximum velocities in storm sewer pipe are generally designed to fall

between 2 and 10 feet per second (fps), respectively. Hydraulic grade lines (HGLs) for the

minor and major storm will be analyzed using StormCAD V8i. The intent will be to maintain

the HGL below finished grade for all proposed storm sewer during the 100-year event.

E. Stormwater Quality/Sediment Erosion Control

On-site detention and water quality storage will be provided through the construction of a

full spectrum detention pond at the downstream point in the development area. Detention

Runoff Summary Table

BASIN TOTAL AREA

(ACRES)

PERCENT IMPERVIOUS

(%)

Q 5 (cfs)

Q 100 (cfs)

A-1

(Historic) 16.39 0% 1.36 34.90

A-1

(Developed) 16.39 55.9% 19.25 51.43

8

volumes and allowable release rates were calculated for the detained area and associated

imperviousness in accordance with the SDDTC manual. The Water Quality Capture

Volume (WQCV) was determined based on the area and imperviousness of the entire site

using the MHFD-Detention spreadsheet.

Maintenance requirements for all best management practices shall be in accordance with

the SDDTC and MHFD Criteria Manuals. The detention pond will be maintained as

recommended in Section 7.0 of the MHFD Criteria manual. The onsite water quality and

detention basin will have low to moderate maintenance requirements, but may require

significant maintenance once every 15 to 25 years.

Pond Maintenance Procedures:

Inspect the water quality and detention basin at least twice annually, observing the amount

of sediment in the forebay and checking for debris at the outlet structure. Remove debris

and litter from the detention area to minimize clogging of the outlet.

When starting from seed, mow native/drought tolerant grasses only when required to deter

weeds during the first there years. Following this period, mowing of native/drought tolerant

grass may stop or be reduced to maintain a height of no less than 6 inches (higher mowing

heights are associated with deeper roots and greater drought tolerance). In general,

mowing should be done as needed to maintain appropriate height and control weeds.

Remove sediment from the forebay and trickle channel annually. The forebay should be

maintained in such a way that it does not provide a significant source of resuspended

sediment in the stormwater runoff. Sediment removal from the micropool is required about

once every one to four years. Small micropools may be vacuumed and larger pools may

need to be pumped in order to remove all sediment from the micropool bottom. Removing

sediment from the micropool will benefit mosquito control. Ensure that the sediment is

disposed of properly and not placed elsewhere in the basin.

9

Remove sediment from the bottom of the basin when accumulated sediment occupies

about 20% of the water quality design volume or when sediment accumulations results in

poor drainage within the basin. The required frequency may be every 15 to 25 years or

more frequently in basins where construction activities are occurring.

Repair basin inlets, outlets, trickle channels, and all other structural components required

for the basin to operate as intended. Repair and vegetate eroded areas as needed

following inspection.

F. Modifications of Criteria

No modifications are being requested for this Site at this time.

V. Drainage Facility Design

A. General Concept

The majority of the Site’s flows will be intercepted by storm sewer and proposed roadside

ditches directed to the on-site water quality detention pond by private storm sewer. Flows

will be treated for water quality, detained, and released to the existing unnamed tributary to

North Turkey Creek adjacent to the Site.

The site is a single basin draining to a full spectrum detention pond, designed in

accordance with the Manual, will provide water quality treatment and stormwater detention.

The pond has been designed to discharge at the 100-year maximum release rate of 18.3

cfs. Additional orifices release the WQCV and the Excess Urban Runoff Volume (EURV) at

the required rates. The flow from these storm events will outfall through a storm sewer pipe

which will discharge to the existing unnamed tributary northeast of the Site. Erosion control

protection in the form of riprap will be placed at the outlet per MHFD criteria.

10

B. Specific Details

The detention facility provides the function of a Detention Pond and is sized to provide the

required detention and water quality volumes. The facility incorporates an outlet structure

to control the water quality release rate, paired with an outlet structure that will release

detained storm water from larger storm events from the developed site at approximately

90% of predeveloped runoff rates for multiple storm events including the WQCV, EURV, 2,

5, 10, 25, 50, and 100-year events. This is known as full spectrum detention and can

reduce urban peak discharges to levels similar to pre-development conditions for the full

spectrum of runoff events from small, frequent storms up to the 100-year event.

To provide sizing for the WQCV, EURV, 2, 5, 10, 25, 50, and 100-year detention as well as

release rates for the Detention Pond, the Detention Basin Volume Estimating Workbook,

MHFD-Detention from MHFD was used. Detention and Storage Calculations are included

in Appendix E.

Proposed Water Quality Detention Pond Summary

Drainage Area

(Acres)

Required WQCV (ac-ft)

Required 100 Year

Volume (ac-ft)

Volume Provided

(ac-ft)

100 Year Release

Rate (CFS)

16.39 0.323 1.472 2.103 18.3

VI. CONCLUSIONS

A. Compliance with Standards

This Site drainage design complies with the Jefferson County’s Storm Design & Technical

Criteria Manual, and the Urban Storm Drainage Criteria Manuals.

11

B. Drainage Concept

This drainage design when properly constructed and maintained will effectively control

stormwater runoff, in accordance with the criteria. As full spectrum detention is proposed,

the drainage design for the proposed development will not have a negative impact on the

receiving drainageway. No adverse effects to either the upstream or downstream adjacent

properties are anticipated.

12

VII. REFERENCES

1. Storm Design & Technical Criteria, Jefferson County, Revised June 01, 2019

2. Urban Storm Drainage Criteria Manual, Vol. 1, Urban Drainage and Flood Control

District, Revised August 2018.


District, Revised September 2017.


District, Revised October 2019.

5. FIRM map 08059C0370F, Jefferson County, Colorado, February 5, 2014, Federal

Emergency Management Agency.

6. United States Department of Agriculture, Natural Resources Conservation Service.

Custom Soil Resource Report.

APPENDIX A – ALTA & FIRM MAP

P

R

E

L

I

M

I

N

A

R

Y

pherlihy

Oval

pherlihy

Callout

APPROXIMATE SITE LOCATION

APPENDIX B – SOIL SURVEY

APPENDIX C – SITE SUB-BASIN RATIONAL CALCULATIONS

Project Name: Conifer Commons Composite C-Value ComputationsPost-Development

Project No: 200115Date: 01/23/20Revised:Design by: PJHChecked by:Soil Group: "C/D"

BASIN TOTAL AREA (ACRES)

ROOFS (90%) DRIVES &

WALKS (90%)

GARAGE & STREETS (100%)

LANDSCAPE AREA (0%)

PERCENT IMPERVIOUS

C2= C5= C10= C100=

DA-1 Pre 16.39 0.000 0.000 0.000 16.393 0.00% 0.00 0.04 0.13 0.48DA-1 Post 16.39 8.487 1.697 0.000 6.208 55.91% 0.43 0.49 0.55 0.71

Conifer Commons Rational Calc.xlsx

Project Name: Designed By: PJH

Project No: Checked By:

Date:

Revised:

FINAL REMARKS

BASIN AREA C5 LENGTH SLOPE Ti LENGTH SLOPE Cv VELOCITY Tt COMPOS. TOTAL Tc = (L/180) + 10 Tc

(AC) (FT) % (MIN) (FT) % (FPS) (MIN) Tc (MIN) LENGTH (MIN) (MIN)DA-1 Pre 16.39 0.04 615 15.00 19.63 1075 13.00 7.00 2.52 7.10 26.73 1,690 19.39 19.39DA-1 Post 16.39 0.49 615 2.00 21.89 1075 3.00 20.00 3.46 5.17 27.06 1,690 19.39 19.39

STANDARD FORM SF-2TIME OF CONCENTRATION

SUB-BASIN INITIAL/OVERLANDDATA TIME (Ti)

200115

Conifer Commons

(URBANIZED BASINS)Tc CHECKTRAVEL TIME

(Tt)

1/23/20


Project Name: Designed By:


Date: Design Storm: 5 YR

Revised: 10-yr 1 hr Rainfall 1.19 IN

BASIN (s) DE

SIG

N P

OIN

T

AR

EA

(AC

)

RU

NO

FF C

OE

FF

Tc (m

in)

C x

A (A

C)

I (IN

/HR

)

DIR

EC

T R

UN

OFF

, Q (C

FS)

Tc (M

AX

)

Σ(C

x A

) (A

C)

I (IN

/HR

)

TOTA

L R

UN

OFF

, Q (C

FS)

DA-1 Pre 1 16.39 0.04 19.39 0.57 2.38 1.36 19.39 0.57 2.38 1.36DA-1 Post 2 16.39 0.49 19.39 8.09 2.38 19.25 19.39 8.09 2.38 19.25

REMARKS

01/23/20 Rational Method Procedure

DIRECT RUNOFF TOTAL RUNOFF

Conifer Commons STANDARD FORM SF-2 PJH

200115 Post-Development


Project Name: Designed By:


Date: Design Storm: 100 YR

Revised: 100-yr 1 hr Rainfall 2.2 IN

BASIN (s) DE

SIG

N P

OIN

T

AR

EA

(AC

)

RU

NO

FF C

OE

FF

Tc (m

in)

C x

A (A

C)

I (IN

/HR

)

DIR

EC

T R

UN

OFF

, Q (C

FS)

Tc (M

AX

)

Σ(C

x A

) (A

C)

I (IN

/HR

)

TOTA

L R

UN

OFF

, Q (C

FS)

DA-1 Pre 1 16.39 0.48 19.39 7.93 4.40 34.90 19.39 7.93 4.40 34.90DA-1 Post 2 16.39 0.71 19.39 11.69 4.40 51.43 19.39 11.69 4.40 51.43

REMARKS

Rational Method Procedure

STANDARD FORM SF-2Post-Development

DIRECT RUNOFF TOTAL RUNOFF

Conifer Commons

200115

01/23/20

PJH


APPENDIX D – MAJOR BASIN CUHP CALCULATIONS

DCIA

Subcatchment Name

EPA SWMM Target Node Raingage

Area(acre)

Length to Centroid (ft)

Length(ft) Slope (ft/ft)

Percent Imperviousness Pervious Impervious

Initial Rate

(in/hr)

Decay Coefficient (1/seconds)

Final Rate

(in/hr)

Level 0, 1, or

2

DA-1 Pre 100 YR 297.53 2400 4675 0.168582888 1.54 0.35 0.1 3 0.0018 0.5 0DA-1 Post 100 YR 297.53 2400 4675 0.168582888 4.68 0.35 0.1 3 0.0018 0.5 0

CUHP SUBCATCHMENTS

Columns with this color heading are for required user-inputColumns with this color heading are for optional override valuesColumns with this color heading are for program-calculated values

Maximum Depression Storage (Watershed inches)

Horton's Infiltration Parameters

Summary of 5 Year Unit Hydrograph Parameters Used By Program and Calculated Results (Version 2.0.1)

Catchment Name/ID User Comment for Catchment CT CpW50

(min.)

W50 Before Peak

W75 (min.)

W75 Before Peak

Time to Peak

(min.) Peak (cfs)Volume

(c.f)Excess

(inches)Excess (c.f.)

Time to Peak (min.)

Peak Flow (cfs)

Total Volume

(c.f.)

Runoff per Unit Area (cfs/acre)

DA-1 Pre 0.158 0.290 25.4 7.15 13.2 5.05 11.9 549 1,080,034 0.14 155,705 40.0 72 155,177 0.24DA-1 Post 0.149 0.273 25.3 6.81 13.2 4.82 11.4 551 1,080,034 0.17 186,773 40.0 80 186,275 0.27

Summary of 100 Year Unit Hydrograph Parameters Used By Program and Calculated Results (Version 2.0.1)

Catchment Name/ID User Comment for Catchment CT CpW50

(min.)

W50 Before Peak

W75 (min.)

W75 Before Peak

Time to Peak

(min.) Peak (cfs)Volume

(c.f)Excess

(inches)Excess (c.f.)

Time to Peak (min.)

Peak Flow (cfs)

Total Volume

(c.f.)

Runoff per Unit Area (cfs/acre)

DA-1 Pre 0.158 0.289 25.4 7.13 13.2 5.04 11.9 549 1,080,034 1.21 1,303,787 40.0 444 1,299,300 1.49DA-1 Post 0.148 0.271 25.3 6.76 13.1 4.78 11.3 552 1,080,034 1.24 1,337,707 40.0 456 1,334,381 1.53

Unit Hydrograph Parameters and Results Excess Precip. Storm Hydrograph

Unit Hydrograph Parameters and Results Excess Precip. Storm Hydrograph

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5 0.00 0.00 5 0.00 0.0010 0.00 0.00 10 0.00 0.0015 0.01 0.09 15 0.01 0.1220 0.04 0.40 20 0.06 0.4325 2.52 8.01 25 3.24 9.0330 34.50 45.84 30 151.68 171.9135 65.16 76.32 35 345.88 366.7940 71.53 79.93 40 444.40 455.8445 61.08 68.49 45 444.24 451.5550 51.22 58.01 50 420.83 426.4455 41.80 48.32 55 382.91 388.0260 35.69 41.77 60 350.36 355.4465 30.28 35.79 65 322.75 327.6370 25.10 30.04 70 284.34 287.8475 19.98 24.48 75 235.43 238.1480 16.36 20.56 80 192.04 195.2785 14.10 17.83 85 160.33 163.4690 12.17 15.47 90 134.52 137.3495 10.35 13.24 95 112.98 115.44100 8.50 10.95 100 93.52 95.58105 6.62 8.59 105 75.51 77.19110 4.76 6.25 110 58.66 59.98115 2.91 3.99 115 42.98 43.96120 1.17 2.02 120 27.92 28.70

flow in cfs

5 Year Storm Hydrographs 100 Year Storm Hydrographs

flow in cfs

APPENDIX E – WATER QUALITY AND DETENTION POND CALCULATIONS

Project:

Basin ID:

Depth Increment = 1.00 ft

Watershed Information Top of Micropool -- 0.00 -- -- -- 0 0.000

Selected BMP Type = EDB -- 1.00 -- -- -- 100 0.002 50 0.001

Watershed Area = 16.39 acres -- 2.00 -- -- -- 12,000 0.275 6,100 0.140

Watershed Length = 1,605 ft -- 3.00 -- -- -- 19,000 0.436 21,600 0.496

Watershed Length to Centroid = 800 ft -- 4.00 -- -- -- 22,000 0.505 42,100 0.966

Watershed Slope = 0.150 ft/ft Steep Slope > 0.06 ft/ft -- 5.00 -- -- -- 25,000 0.574 65,600 1.506

Watershed Imperviousness = 60.00% percent Spillway -- 6.00 -- -- -- 27,000 0.620 91,600 2.103

Percentage Hydrologic Soil Group A = 0.0% percent -- -- -- --

Percentage Hydrologic Soil Group B = 0.0% percent -- -- -- --

Percentage Hydrologic Soil Groups C/D = 100.0% percent -- -- -- --

Target WQCV Drain Time = 40.0 hours -- -- -- --

Location for 1-hr Rainfall Depths = Columbine Valley - Town Hall -- -- -- --

-- -- -- --

-- -- -- --

Optional User Overrides -- -- -- --

Water Quality Capture Volume (WQCV) = 0.323 acre-feet acre-feet -- -- -- --

Excess Urban Runoff Volume (EURV) = 0.944 acre-feet acre-feet -- -- -- --

2-yr Runoff Volume (P1 = 0.85 in.) = 0.624 acre-feet 0.85 inches -- -- -- --



25-yr Runoff Volume (P1 = 1.65 in.) = 1.641 acre-feet inches -- -- -- --



500-yr Runoff Volume (P1 = 3 in.) = 3.541 acre-feet inches -- -- -- --

Approximate 2-yr Detention Volume = 0.601 acre-feet -- -- -- --






-- -- -- --

Define Zones and Basin Geometry -- -- -- --

Zone 1 Volume (WQCV) = 0.323 acre-feet -- -- -- --

Zone 2 Volume (EURV - Zone 1) = 0.622 acre-feet -- -- -- --

Zone 3 Volume (100-year - Zones 1 & 2) = 0.528 acre-feet -- -- -- --

Total Detention Basin Volume = 1.472 acre-feet -- -- -- --

After providing required inputs above including 1-hour rainfalldepths, click 'Run CUHP' to generate runoff hydrographs using

the embedded Colorado Urban Hydrograph Procedure.

Volume (ft 3)

Volume (ac-ft)

Area (acre)

DETENTION BASIN STAGE-STORAGE TABLE BUILDER

Optional Override Area (ft 2)

Length (ft)

Optional Override Stage (ft)

Stage(ft)

Stage - StorageDescription

Area (ft 2)

Width (ft)

Conifer Commons

A-1

MHFD-Detention, Version 4.00 (December 2019)

Example Zone Configuration (Retention Pond)

Conifer Commons-MHFD-Detention_v4 00.xlsm, Basin 1/23/2020, 6:16 PM

Project:

Basin ID:

Estimated Estimated

Stage (ft) Volume (ac-ft) Outlet Type

Zone 1 (WQCV) 2.57 0.323 Orifice Plate

Zone 2 (EURV) 3.96 0.622 Orifice Plate

Zone 3 (100-year) 4.95 0.528 Weir&Pipe (Restrict)

Total (all zones) 1.472

User Input: Orifice at Underdrain Outlet (typically used to drain WQCV in a Filtration BMP) Calculated Parameters for UnderdrainUnderdrain Orifice Invert Depth = N/A ft (distance below the filtration media surface) Underdrain Orifice Area = N/A ft2

Underdrain Orifice Diameter = N/A inches Underdrain Orifice Centroid = N/A feet

User Input: Orifice Plate with one or more orifices or Elliptical Slot Weir (typically used to drain WQCV and/or EURV in a sedimentation BMP) Calculated Parameters for PlateInvert of Lowest Orifice = 0.00 ft (relative to basin bottom at Stage = 0 ft) WQ Orifice Area per Row = N/A ft2

Depth at top of Zone using Orifice Plate = 3.96 ft (relative to basin bottom at Stage = 0 ft) Elliptical Half-Width = N/A feetOrifice Plate: Orifice Vertical Spacing = 15.80 inches Elliptical Slot Centroid = N/A feet

Orifice Plate: Orifice Area per Row = N/A inches Elliptical Slot Area = N/A ft2

User Input: Stage and Total Area of Each Orifice Row (numbered from lowest to highest)Row 1 (required) Row 2 (optional) Row 3 (optional) Row 4 (optional) Row 5 (optional) Row 6 (optional) Row 7 (optional) Row 8 (optional)

Stage of Orifice Centroid (ft) 0.00 1.32 2.64

Orifice Area (sq. inches) 1.38 1.38 3.14

Row 9 (optional) Row 10 (optional) Row 11 (optional) Row 12 (optional) Row 13 (optional) Row 14 (optional) Row 15 (optional) Row 16 (optional)

Stage of Orifice Centroid (ft)

Orifice Area (sq. inches)

User Input: Vertical Orifice (Circular or Rectangular) Calculated Parameters for Vertical OrificeNot Selected Not Selected Not Selected Not Selected

Invert of Vertical Orifice = N/A N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Area = N/A N/A ft2

Depth at top of Zone using Vertical Orifice = N/A N/A ft (relative to basin bottom at Stage = 0 ft) Vertical Orifice Centroid = N/A N/A feetVertical Orifice Diameter = N/A N/A inches

User Input: Overflow Weir (Dropbox with Flat or Sloped Grate and Outlet Pipe OR Rectangular/Trapezoidal Weir (and No Outlet Pipe) Calculated Parameters for Overflow Weirgrate Zone 3 Weir Not Selected Zone 3 Weir Not Selected

Overflow Weir Front Edge Height, Ho = 5.42 N/A ft (relative to basin bottom at Stage = 0 ft) Height of Grate Upper Edge, Ht = 5.42 N/A feetOverflow Weir Front Edge Length = 37.00 N/A feet Overflow Weir Slope Length = 37.00 N/A feet

Overflow Weir Grate Slope = 0.00 N/A H:V Grate Open Area / 100-yr Orifice Area = 521.32 N/AHoriz. Length of Weir Sides = 37.00 N/A feet Overflow Grate Open Area w/o Debris = 958.30 N/A ft2

Overflow Grate Open Area % = 70% N/A %, grate open area/total area Overflow Grate Open Area w/ Debris = 479.15 N/A ft2

Debris Clogging % = 50% N/A %

User Input: Outlet Pipe w/ Flow Restriction Plate (Circular Orifice, Restrictor Plate, or Rectangular Orifice) Calculated Parameters for Outlet Pipe w/ Flow Restriction PlateZone 3 Restrictor Not Selected Zone 3 Restrictor Not Selected

Depth to Invert of Outlet Pipe = 0.00 N/A ft (distance below basin bottom at Stage = 0 ft) Outlet Orifice Area = 1.84 N/A ft2

Outlet Pipe Diameter = 21.00 N/A inches Outlet Orifice Centroid = 0.70 N/A feetRestrictor Plate Height Above Pipe Invert = 15.00 inches Half-Central Angle of Restrictor Plate on Pipe = 2.01 N/A radians

User Input: Emergency Spillway (Rectangular or Trapezoidal) Calculated Parameters for SpillwaySpillway Invert Stage= 5.60 ft (relative to basin bottom at Stage = 0 ft) Spillway Design Flow Depth= 0.88 feet

Spillway Crest Length = 16.00 feet Stage at Top of Freeboard = 7.48 feetSpillway End Slopes = 4.00 H:V Basin Area at Top of Freeboard = 0.62 acres

Freeboard above Max Water Surface = 1.00 feet Basin Volume at Top of Freeboard = 2.10 acre-ft

Max Ponding Depth of Target Storage Volume = 5.57 feet Discharge at Top of Freeboard = 33.50 cfs

Routed Hydrograph ResultsDesign Storm Return Period = WQCV EURV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 500 YearOne-Hour Rainfall Depth (in) = 0.53 1.07 0.85 1.19 1.39 1.65 1.93 2.20 3.00

CUHP Runoff Volume (acre-ft) = 0.323 0.944 0.624 0.999 1.247 1.641 2.016 2.423 3.541Inflow Hydrograph Volume (acre-ft) = 0.323 0.944 0.624 0.999 1.247 1.641 2.016 2.423 3.541CUHP Predevelopment Peak Q (cfs) = 0.0 0.0 0.2 3.4 5.9 12.1 16.6 21.6 34.7

OPTIONAL Override Predevelopment Peak Q (cfs) = 0.0 0.0Predevelopment Unit Peak Flow, q (cfs/acre) = 0.00 0.00 0.01 0.21 0.36 0.74 1.01 1.32 2.12

Peak Inflow Q (cfs) = 6.0 18.1 11.6 19.2 23.3 31.3 38.5 47.1 67.7Peak Outflow Q (cfs) = 0.1 0.3 0.2 0.3 0.3 0.4 4.3 18.3 32.2

Ratio Peak Outflow to Predevelopment Q = N/A N/A N/A 0.1 0.1 0.0 0.3 0.8 0.9Structure Controlling Flow = Plate Plate Plate Plate Plate Plate Overflow Weir 1 Outlet Plate 1 Spillway

Max Velocity through Grate 1 (fps) = N/A N/A N/A N/A N/A N/A 0.0 0.0 0.0Max Velocity through Grate 2 (fps) = N/A N/A N/A N/A N/A N/A N/A N/A N/A

Time to Drain 97% of Inflow Volume (hours) = 39 70 56 72 80 92 96 94 90Time to Drain 99% of Inflow Volume (hours) = 40 73 59 75 85 97 102 102 100

Maximum Ponding Depth (ft) = 2.51 3.87 3.21 3.98 4.44 5.14 5.47 5.57 5.98Area at Maximum Ponding Depth (acres) = 0.36 0.50 0.45 0.50 0.54 0.58 0.60 0.60 0.62

Maximum Volume Stored (acre-ft) = 0.301 0.896 0.589 0.951 1.195 1.581 1.781 1.835 2.084

DETENTION BASIN OUTLET STRUCTURE DESIGNMHFD-Detention, Version 4.00 (December 2019)

Conifer Commons

A-1

The user can override the default CUHP hydrographs and runoff volumes by entering new values in the Inflow Hydrographs table (Columns W through AF).

Example Zone Configuration (Retention Pond)

COUNTA for Basin Tab = 1 Ao Dia WQ Plate Type Vert Orifice 1Vert Orifice 2Count_Underdrain = 0 0.11(diameter = 3/8 inch) 2 1 1

Count_WQPlate = 1 0.14(diameter = 7/16 inch)

Count_VertOrifice1 = 0 0.18(diameter = 1/2 inch) Outlet Plate 1 Outlet Plate 2 Drain Time Message Boolean

Count_VertOrifice2 = 0 0.24(diameter = 9/16 inch) 4 1 5yr, <72hr 0

Count_Weir1 = 1 0.29(diameter = 5/8 inch) >5yr, <120hr 0

Count_Weir2 = 0 0.36(diameter = 11/16 inch) Max Depth Row

Count_OutletPipe1 = 1 0.42(diameter = 3/4 inch) WQCV 252 Watershed Constraint Check

Count_OutletPipe2 = 0 0.50(diameter = 13/16 inch) 2 Year 322 Slope 0.040

COUNTA_2 (Standard FSD Setup)= 1 0.58(diameter = 7/8 inch) EURV 388 Shape 3.61

Hidden Parameters & Calculations 0.67(diameter = 15/16 inch) 5 Year 399

MaxPondDepth_Error? FALSE 0.76 (diameter = 1 inch) 10 Year 445 Spillway Depth

Cd_Broad-Crested Weir 3.00 0.86(diameter = 1-1/16 inches) 25 Year 515 0.88

WQ Plate Flow at 100yr depth = 0.38 0.97(diameter = 1-1/8 inches) 50 Year 548

CLOG #1= 35% 1.08(diameter = 1-3/16 inches) 100 Year 558 1 Z1_Boolean

Cdw #1 = 1.15 1.20(diameter = 1-1/4 inches) 500 Year 599 1 Z2_Boolean

Cdo #1 = 1.07 1.32(diameter = 1-5/16 inches) Zone3_Pulldown Message 1 Z3_Boolean

Overflow Weir #1 Angle = 0.000 1.45(diameter = 1-3/8 inches) 1 Opening Message

CLOG #2= 0% 1.59(diameter = 1-7/16 inches) Draintime Running

Cdw #2 = #VALUE! 1.73(diameter = 1-1/2 inches) Outlet Boolean Outlet Rank Total (1 to 4)

Cdo #2 = #VALUE! 1.88(diameter = 1-9/16 inches) Vertical Orifice 1 0 0 1

Overflow Weir #2 Angle = #VALUE! 2.03(diameter = 1-5/8 inches) Vertical Orifice 2 0 0 Boolean

Underdrain Q at 100yr depth = 0.00 2.20(diameter = 1-11/16 inches) Overflow Weir 1 1 1 0 Max Depth

VertOrifice1 Q at 100yr depth = 0.00 2.36(diameter = 1-3/4 inches) Overflow Weir 2 0 0 0 500yr Depth

VertOrifice2 Q at 100yr depth = 0.00 2.54(diameter = 1-13/16 inches) Outlet Pipe 1 1 1 1 Freeboard

2.72(diameter = 1-7/8 inches) Outlet Pipe 2 0 0 1 Spillway

Count_User_Hydrographs 0 2.90(diameter = 1-15/16 inches) 0 Spillway Length

CountA_3 (EURV & 100yr) = 1 3.09(diameter = 2 inches) FALSE Time Interval

CountA_4 (100yr Only) = 1 3.29(use rectangular openings) Button Visibility Boolean

COUNTA_5 (FSD Weir Only)= 0 0 WQCV Underdrain

COUNTA_6 (EURV Weir Only)= 1 1 WQCV Plate

0 EURV-WQCV Plate

Outlet1_Pulldown_Boolean 0 EURV-WQCV VertOriice

Outlet2_Pulldown_Boolean 1 Outlet 90% Qpeak

Outlet3_Pulldown_Boolean 0 Outlet Undetained

0 Weir Only 90% Qpeak

0 Five Year Ratio Plate

0 Five Year Ratio VertOrifice

EURV_draintime_user

Spillway Options

Offset

Overlapping

S-A-V-D Chart Axis Default X-axis Left Y-Axis Right Y-Axisminimum bound 0.00 0 0maximum bound 8.00 100,000 40

DETENTION BASIN OUTLET STRUCTURE DESIGNMHFD-Detention, Version 4.00 (December 2019)

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APPENDIX F – SITE DRAINAGE PLAN

AC

BASIN

AREA CMINORMAJOR

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Know what's below.

Call before you dig.

CALL 3 BUSINESS DAYS IN ADVANCE BEFORE YOU DIG, GRADE,

OR EXCAVATE FOR THE MARKING OF UNDERGROUND MEMBER

UTILITIES.

ISSUE DATE:DATE REVISION COMMENTS

SHEET NO.

DESIGNED BY:CHECKED BY:DRAWN BY:

PROJECT #:

PLOT

TED:

FRI

01/24

/20 11

:02:40

A B

Y: P

AT H

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Denver, Colorado 80203

P: 303.623.6300 F: 303.623.6311

HarrisKocherSmith.com

11 OF 2

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PJHREVIEWERDRAFTER

200115

CONIFER COMMONSDRAINAGE PLAN

PWN ARCHITECTS AND PLANNERS. INC.#### ####

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BASINDESIGNATION

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C COEFFICIENT

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1.23AC

BASIN

AREA CMINORMAJOR

OS 1

1 BASIN DESIGN POINT

5-YR RATIONAL (POST-PROJECT)


RUNOFF SUMMARY TABLEBASIN DESIGN POINT AREA (AC) % IMPERVIOUS Q5 (CFS) Q100 (CFS)A-1 Pre 1 16.39 0.00% 1.36 34.90A-1 Post 1 16.39 55.91% 19.25 51.43

APPENDIX G – MAJOR BASIN DRAINAGE PLAN

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Know what's below.

Call before you dig.

CALL 3 BUSINESS DAYS IN ADVANCE BEFORE YOU DIG, GRADE,

OR EXCAVATE FOR THE MARKING OF UNDERGROUND MEMBER

UTILITIES.

ISSUE DATE:DATE REVISION COMMENTS

SHEET NO.

DESIGNED BY:CHECKED BY:DRAWN BY:

PROJECT #:

PLOT

TED:

FRI

01/24

/20 12

:12:15

P B

Y: P

AT H

ERLIH

Y


Denver, Colorado 80203

P: 303.623.6300 F: 303.623.6311

HarrisKocherSmith.com

22 OF 2

####

PJHREVIEWERDRAFTER

200115

CONIFER COMMONSMAJOR BASIN DRAINAGE PLAN

PWN ARCHITECTS AND PLANNERS. INC.#### ####

#### ####

#### ####

#### ####

#### ####

#### ######## ####

NO C

HANG

ES A

RE T

O BE

MAD

E TO

THI

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AWIN

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BASINDESIGNATION

BASIN SIZEIN ACRES

C COEFFICIENT

C COEFFICIENT0.450.67

1.23AC

BASIN

AREA CMINORMAJOR

OS 1

1 BASIN DESIGN POINT



RUNOFF SUMMARY TABLEBASIN DESIGN POINT AREA (AC) % IMPERVIOUS Q5 (CFS) Q100 (CFS)DA-1 Pre 1 297.53 1.54% 71.53 444.40DA-1 Post 1 297.53 4.68% 79.93 455.84

South Santa Fe PD Phase 1 Drainage Report · plan of the historical drainage basin is included in...

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Transcript of South Santa Fe PD Phase 1 Drainage Report · plan of the historical drainage basin is included in...