preliminary drainage report - city of thornton … · i hereby certify that this report (plan) for...

FINAL DRAINAGE REPORT CORNERSTONE RIVER VALLEY VILLAGE FILING NO. 1

CITY OF THORNTON, COUNTY OF ADAMS, STATE OF COLORADO

PREPARED FOR:

Thornton Cornerstone LLC 558 Castle Pines Parkway

Suite B4-321 Castle Pines, CO 80108

Ph: 720-341-6358 Attn: Joseph H. Quinn

PREPARED BY:

Contact: David R. Addor, P.E.

ORIGINAL DATE PREPARED: April 26, 2016 REVISED:

TABLE OF CONTENTS

Page No.

1. General Location and Description….…………………………………………………… 3 2. Drainage Basins & Sub-Basins…………………………………………………………. 3-4 3. Drainage Design Criteria…..……………………………………………………………. 4-5 4. Drainage Facility Design ……………………………………………………………….. 5-6 5. Conclusions……………………………………………………………………………….. 6 6. List of References………………………………………………………………………... 6

Appendix: 7

Basin and Runoff Calculations 9 (19 sheets) Storm Sewer Calculations 29 (13 sheets) Backup Information 43 (6 sheets) (Firmette, Soils Information)

Cornerstone River Valley Village - 2 - Engineering Service Company

Thornton Cornerstone LLC herby certifies that the drainage facilities for Cornerstone River Valley Village Filing No. 1 will be constructed according to the design presented in this report. I understand that the City of Thornton does not and shall not assume liability for the drainage facilities designed and/or certified by my engineer. I understand that the City of Thornton reviews drainage plans but cannot, on behalf of Thornton Cornerstone LLC, guarantee that final drainage design review will absolve Thornton Cornerstone LLC and/or their successors and/or assigns of future liability for improper design. I further understand that approval of the Plat and/o Development Permit does not imply approval of my engineer’s drainage design. Attest: Name of Responsible Party ________________________________ _________________________ ________________________________ Notary Public Authorized Signature I hereby certify that this report (plan) for the final drainage design of Cornerstone River Valley Village Filing No. 1 was prepared by me (or under my direct supervision) in accordance with the provisions of the City of Thornton Standards and Specifications for the Design and Construction of Public and Private Improvements for the Responsible Parties thereof. I understand that the City of Thornton does not and shall not assume liability for drainage facilities designed by others. _____________________________________ Registered Professional Engineer State of Colorado No. ___________________


1. General Location and Description a. Location This property is located in the SW ¼ of Section 18, T. 2 S.,

R. 67 W. of the 6th P.M. It is located on the northeast corner of Colorado Boulevard and Thornton Parkway to the west of Clermont Street. The Colorado Agricultural Ditch runs along the western edge of the property.

This site is bounded on the west by The Reserve at

Thornton on the west side of Colorado Boulevard and Cherrylane Subdivision to the south on the south side of Thornton Parkway. To the north and east are undeveloped portions of River Valley Village Subdivision.

b. Description of Property This first filing for Cornerstone River Valley Village will

subdivide the south 14.23 acres of the western portion of the River Valley Village Subdivision. Tract D containing 18.22 acres will be subject to future platting for additional residential development.

The property is sparsely covered with native grasses.

Grades are generally to the south and east at slopes between 1 and 3 percent. Thornton Parkway is elevated from 2 to 10 feet above this site along the south boundary. Soils are generally Ulm Loams which is a hydrologic group C soil. Other soils within this western portion of River Valley Village Subdivision are Samsil Shingle Complex located generally on the northwest quadrant of 32.45 acres. This is a hydrologic group D soil.

The proposal for this first phase is to subdivide this portion of

the property into 79 single family residential lots.

2. Drainage Basins and Sub-basins

a. Major Basin Description

This site lies outside of the100-year floodplain. It appears on two FIRMs as provided by FEMA, Map Number 08001C0602H and 08001C0606H, both dated March 5, 2007.


This site falls within the Basin 4100 and Direct Flow Area 0056 Outfall System Planning Study prepared for the City of Thornton and Adams County by Kiowa Engineering, March 2001. Reach 5602-2 lies along the alignment for Thornton Parkway. It is not the existing flow path for any existing runoff. Local storm sewer is identified to control drainage.

b. Sub-Basin Description

This site is part of the River Valley Village Subdivision – Amendment No. 1. That plat was the subject of a Final Drainage Report prepared by Manhard Consulting as approved by the City of Thornton on May 23, 2002. It has since been the subject of a Preliminary Drainage Report prepared by VLC, LLC that revised the original Manhard report to change the uses on the 32.45 acres that lie within Cornerstone River Valley Village Filing No. 1. This report rationalizes the basins in the southern 15.20 acres to align with the proposal street and storm sewer layout.

3. Drainage Design Criteria

a. Regulations

The key variation from the City of Thornton Standards is the use of the Rational Method for runoff calculations. This was done due to the relatively small sizes of the various sub-basins created by the storm sewer system.

b. Development Criteria Reference and Constraints

As stated above, this property was the subject of a previous final drainage report by Manhard Consulting. That report set in place the existing detention facility for the overall River Valley Village complex. The discharge from this site will be to the existing storm sewer system that directs the flows to this pond.

c. Hydrological Criteria

The design rainfall is taken from the City of Thornton Standards and Specifications. The five year one-hour rainfall is 1.38 inches and the 100-year one-hour rainfall is 2.69 inches.


Runoff calculations were done using the Rational Method. The rainfall intensities were generated using the UDFCD formula applying the one-hour rainfall for the 5-year and 100-year storms.

d. Hydraulic Criteria

Water surface profiles were calculated for the storm sewer system using the UDFCD NeoUDSewer program. Streets and inlets will be evaluated using UDFCD UD-Inlet.

4. Drainage Facility Design a. General Concept

The drainage pattern for this site will be the simple collection of runoff in the proposed street system and directed to the storm sewer system for delivery to the existing detention pond. There is little offsite drainage that impacts this first filing. Minor flows may collect along the northern boundary and will be directed to the existing storm system in Clermont Street. The project site has been divided into thirteen (13) sub-basins with one off-site basin. See the Drainage Plan. All of the basins are similar and were developed to show discharge to the proposed storm sewer system. The outfall will be into the existing 36” RCP storm sewer at the intersection of Thornton Parkway and Clermont Street.

b. Specific Details There were no specific drainage problems encountered. The off-site basin is the existing Basin identified as CPA:1 on the VLC plan or 14C on the Manhard Plan. This basin consists of the right-of-way for Colorado Boulevard and Thornton Parkway adjacent to this site. No new calculations are included for this basin as it does not impact the proposed subdivision. Detention will be provided in the existing pond located at the northwest corner of Thornton Parkway and Riverdale Road.


Inlet calculations are included for key locations. Design Point 1 has the maximum flow and the calculations show that it requires a 10 foot Type R inlet. Design Point 6 has the high median flow and was calculated as the maximum for a 5 foot Type R inlet. All inlets that receive more flow are sized as 10 foot.

5. Conclusions

a. Compliance with Standards

The drainage for this site complies with all City of Thornton Standards and Specifications and with the Urban Drainage Flood Control District Criteria Manual.

b. Drainage Concept

The drainage design will control the runoff as anticipated in the previous reports and direct it to the existing detention facility.

F. LIST OF REFERENCES

#1) “Standards and Specifications for the Design and Construction of Public and Private Improvements”, City of Thornton, Colorado. October 2012.

#2) “Urban Storm Drainage Criteria Manual - Volumes 1,2, and 3”,

Urban Drainage and Flood Control District, Denver, Colorado. Published June 2001, latest edition.

#3) Phase III Drainage Study for River Valley Village Subdivision,

prepared by Manhard Consulting, Ltd., May, 2002. #4) Phase I Drainage Report for Cornerstone River Valley Ranch,

prepared by Vision Land Connection, LLC, August, 2015. #5) “Soil Map – Arapahoe County, Colorado”, United States

Department of Agriculture, Natural Resources Conservation Service, Web Soil Survey 2.2.


APPENDIX


BASIN & RUNOFF CALCULATIONS

Cornerstone RVV 4/28/2016

Cornerstone River Valley VillageSite Data:

Total Basin: 662,027 Sq. Ft. 15.198 Acres#REF!

Composite Coefficient of Runoff: (Developed Area)Surface Area % of Site C2 value C5 value C10 value C100 value Imp.Drives & Walks 51,230 7.74% 0.87 0.88 0.90 0.93 0.90Asphalt Pavement 141,590 21.39% 0.80 0.85 0.90 0.90 1.00Roof 190,020 28.70% 0.15 0.25 0.35 0.65 0.90Landscaping 279,187 42.17% 0.10 0.11 0.13 0.15 0.02Figures are from Table 1, City of Aurora Storm Drainage Design & Technical Criteria

Formula: (% of Site)(C Value)+(% of SIte)(C Value)+(% of Site)(C Value) = CCResults: C2: 0.324

C5: 0.368C10: 0.417

C100: 0.514

Developed Basin Imperviousness:

I= 55.0%


Sub-Basin Calculations:Basin Designation: C2

Design Point: 1Basin Area: 127,392 Sq. Ft. 2.925 Acres

Composite Coefficient of Runoff:Surface Area % of Site C2 value C5 value C10 value C100 value Imp.Drives & Walks 11,310 8.88% 0.73 0.75 0.77 0.83 0.90Asphalt Pavement 17,260 13.55% 0.89 0.90 0.92 0.95 1.00Roof 41,120 32.28% 0.73 0.75 0.77 0.83 0.90Landscaping 57,702 45.29% 0.02 0.08 0.15 0.35 0.00Figures are from Table RO-3 and Figures RO-3 thru RO-5, Urban Drainage and Flood Control District Criteria Manual

Formula: (% of Site)(C Value)+(% of SIte)(C Value)+(% of Site)(C Value) = CC

C2: 0.43C5: 0.47

C10: 0.49C100: 0.61


I= 0.506

Basin Designation: C3




C2: 0.50C5: 0.53

C10: 0.53C100: 0.64


I= 0.579






C2: 0.43C5: 0.47

C10: 0.49C100: 0.62


I= 0.509

Basin Designation: C5Design Point: 3

Basin Area: 35,897 Sq. Ft. 0.824 Acres



C2: 0.54C5: 0.57

C10: 0.55C100: 0.66


I= 0.621






C2: 0.45C5: 0.48

C10: 0.50C100: 0.62


I= 0.524



Composite Coefficient of Runoff:Surface Area % of Site C2 value C5 value C10 value C100 value Imp.Drives & Walks - 0.00% 0.73 0.75 0.77 0.83 0.90Asphalt Pavement 4,780 61.45% 0.89 0.90 0.92 0.95 1.00Roof - 0.00% 0.73 0.75 0.77 0.83 0.90Landscaping 2,999 38.55% 0.02 0.08 0.15 0.35 0.00Figures are from Table RO-3 and Figures RO-3 thru RO-5, Urban Drainage and Flood Control District Criteria Manual


C2: 0.55C5: 0.58

C10: 0.53C100: 0.64


I= 0.614






C2: 0.44C5: 0.48

C10: 0.50C100: 0.62


I= 0.519





C2: 0.52C5: 0.55

C10: 0.54C100: 0.65


I= 0.595






C2: 0.49C5: 0.52

C10: 0.52C100: 0.64


I= 0.569





C2: 0.46C5: 0.50

C10: 0.51C100: 0.63


I= 0.540






C2: 0.48C5: 0.52

C10: 0.52C100: 0.64


I= 0.562





C2: 0.48C5: 0.51

C10: 0.52C100: 0.63


I= 0.558



Design Point:Basin Area: 49,135 Sq. Ft. 1.128 Acres



C2: 0.46C5: 0.49

C10: 0.50C100: 0.62


I= 0.529

STANDARD FORM SF - 1TIME OF CONCENTRATION

Project: Cornerstone River Valley VillageCALCULATED BY: DRA DATE: 04/06/16 tc = ti + tt

SUB - BASIN INITIAL / OVERLAND TRAVEL TIME tc CHECK FINAL REMARKSDATA TIME (ti) (tt) (URBANIZED BASINS) tc

DESIGN AREA C5 LENGTH SLOPE ti LENGTH SLOPE VEL. tt COMP. TOTAL LEGNTH tc=(l/180)+10

POINT Ac Ft % Min Ft % FPS Min tc (Ft) Min Min(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)

C2 2.92 0.47 200 3.0 11.4 550 2.1 2.9 3.2 15 750 14 15

C3 0.72 0.53 110 2.5 8.0 240 2.1 2.9 1.4 9 350 12 9

C4 1.54 0.47 140 2.9 9.6 300 2.0 2.8 1.8 11 440 12 11

C5 0.82 0.57 90 2.3 7.0 420 2.5 3.2 2.2 9 510 13 9

C6 0.96 0.48 130 4.5 7.8 180 2.9 3.4 0.9 9 310 12 9

C8 1.31 0.48 120 3.3 8.4 270 2.0 2.8 1.6 10 390 12 10

C9 0.57 0.55 80 3.0 6.3 245 2.0 2.8 1.4 8 325 12 8

C10 1.62 0.52 75 4.0 5.8 400 2.1 2.9 2.3 8 475 13 8

C11 1.25 0.50 145 4.0 8.4 200 1.9 2.8 1.2 10 345 12 10

C12 1.25 0.52 130 3.0 8.5 460 2.9 3.4 2.3 11 590 13 11

C13 0.93 0.51 140 5.0 7.4 300 3.0 3.5 1.4 9 440 12 9

C14 1.13 0.49 240 2.0 13.7 280 1.0 2.0 2.3 16 520 13 16

STORM DRAINAGE DESIGN AND TECHNICAL MANUAL

CALCULATED BY: DRA STANDARD FORM SF - 2 JOB NO: DATE: STORM DRAINAGE SYSTEM DESIGN PROJECT: Cornerstone River Valley Village

CHECKED BY: DRA (RATIONAL METHOD PROCEDURE) DESIGN STORM: 5 YR1 Hour Rainfall: 1.38

DIRECT RUNOFF TOTAL RUNOFF STREET PIPE TRAVEL TIME

STREET

DES

IGN

PO

INT

AREA

D

ESIG

N

AREA

(A

C)

RU

NO

FF

CO

EFF

tc

(MIN

)

C . A

(A

C)

I

IN /

HR

Q

(CFS

)

tc

(M

IN)

SUM

C . A

(A

C)

I

IN /

HR

Q

(CFS

)

SLO

PE

(%)

STR

EET

FLO

W(C

FS)

DES

IGN

FL

OW

(CFS

)

SLO

PE

(%)

PIPE

SIZE

LEN

GTH

(FT)

VELO

CIT

Y

(F

PS)

t t

(MIN

)

REMARKS

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22)1 1 C2 2.92 0.47 15 1.37 3.18 4.34

2 2 C3 0.72 0.53 9 0.38 3.82 1.46

3 2 C4 1.54 0.47 11 0.72 3.54 2.55 11 1.10 3.54 3.90 3.90 2 18 263.0 7.40 0.6 C3 + C4

4 3 C5 0.82 0.57 9 0.47 3.86 1.82 15 2.94 3.18 9.34 C2 TO C5

5 4 C6 0.96 0.48 9 0.46 3.94 1.83

6 5 C7 0.18 0.58 5 0.10 4.68 0.49 8.7 0.57 3.94 2.24 2.24 2 18 393.0 6.30 1.0 C6 + C7

7 6 C8 1.31 0.48 10 0.63 3.73 2.34

8 7 C9 0.57 0.55 8 0.31 4.11 1.29 10 1.51 3.73 5.63 C 6 TO C9

15 4.45 3.18 14.14 14.14 2 30 187.0 10.40 0.3 C2 TO C9STORM DRAINAGE DESIGN AND TECHNICAL MANUAL

4/6/2016




STREET

DE

SIG

N

PO

INT

AR

EA

D

ES

IGN

AR

EA

(A

C)

RU

NO

FF

CO

EFF

tc

(MIN

)

C . A

(A

C)

I

IN /

HR

Q

(CFS

)

tc

(M

IN)

SU

M C

. A

(AC

)

I

IN /

HR

Q

(CFS

)

SLO

PE

(%

)

STR

EE

T FL

OW

(CFS

)

DE

SIG

N

FLO

W(C

FS)

SLO

PE

(%

)

PIP

E

S

IZE

LEN

GTH

(FT)

VE

LOC

ITY

(FP

S)

t t

(MIN

)

REMARKS

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22)1 8 C10 1.62 0.52 8 0.85 4.04 3.42 15 5.29 3.15 16.66 C2 TO C10

2 9 C11 1.25 0.50 10 0.62 3.79 2.35 15 5.91 3.15 18.61 C2 TO C11

3 10 C12 1.25 0.52 11 0.64 3.63 2.34

4 10 C13 0.93 0.51 9 0.48 3.91 1.88 11 1.13 3.63 4.09 C12 TO C13

5 11 C14 1.13 0.49 16 0.56 3.03 1.68 16 1.68 3.03 5.10 C13 TO C14

6

7

8


4/6/2016




STREET

DE

SIG

N

PO

INT

AR

EA

D

ES

IGN

AR

EA

(A

C)

RU

NO

FF

CO

EFF

tc

(MIN

)

C . A

(A

C)

I

IN /

HR

Q

(CFS

)

tc

(M

IN)

SU

M C

. A

(AC

)

I

IN /

HR

Q

(CFS

)

SLO

PE

(%

)

STR

EE

T FL

OW

(CFS

)

DE

SIG

N

FLO

W(C

FS)

SLO

PE

(%

)

PIP

E

S

IZE

LEN

GTH

(FT)

VE

LOC

ITY

(FP

S)

t t

(MIN

)

REMARKS

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22)1 1 C2 2.92 0.61 15 1.79 6.20 11.10

2 2 C3 0.72 0.64 9 0.46 7.45 3.44

3 2 C4 1.54 0.62 11 0.94 6.91 6.53 11 1.41 6.91 9.71 C3 + C4

4 3 C5 0.82 0.66 9 0.54 7.52 4.10 15 3.74 6.20 23.18 C2 TO C5

5 4 C6 0.96 0.62 9 0.60 7.67 4.59

6 5 C7 0.18 0.64 5 0.12 9.12 1.05 9 0.71 7.67 5.47 C6 + C7

7 6 C8 1.31 0.62 10 0.81 7.28 5.92

8 7 C9 0.57 0.65 8 0.37 8.00 2.97 10 1.90 7.28 13.82 C 6 TO C9

15 5.64 6.20 34.95 C2 TO C9STORM DRAINAGE DESIGN AND TECHNICAL MANUAL

4/6/2016




STREET

DE

SIG

N

PO

INT

AR

EA

D

ES

IGN

AR

EA

(A

C)

RU

NO

FF

CO

EFF

tc

(MIN

)

C . A

(A

C)

I

IN /

HR

Q

(CFS

)

tc

(M

IN)

SU

M C

. A

(AC

)

I

IN /

HR

Q

(CFS

)

SLO

PE

(%

)

STR

EE

T FL

OW

(CFS

)

DE

SIG

N

FLO

W(C

FS)

SLO

PE

(%

)

PIP

E

S

IZE

LEN

GTH

(FT)

VE

LOC

ITY

(FP

S)

t t

(MIN

)

REMARKS

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22)1 8 C10 1.62 0.64 8 1.03 7.88 8.14 15 6.67 6.14 40.95 C2 TO C10

2 9 C11 1.25 0.63 10 0.78 7.39 5.78 15 7.45 6.14 45.75 C2 TO C11

3 10 C12 1.25 0.64 11 0.79 7.08 5.62

4 10 C13 0.93 0.63 9 0.59 7.62 4.51 11 1.39 7.08 9.81 C12 TO C13

5 11 C14 1.13 0.62 16 0.70 5.91 4.13 16 2.08 5.91 12.32 C13 TO C14

6

7

8


4/6/2016

Cornerstone DP 1 UD-Inlet_v3.14.xlsm, Q-Peak 4/28/2016, 9:48 AM

Worksheet Protected

Project:Inlet ID:

Design Flow: ONLY if already determined through other methods: Minor Storm Major Storm (local peak flow for 1/2 of street OR grass-lined channel): *QKnown = 4.3 11.1 cfs

* If you enter values in Row 14, skip the rest of this sheet and proceed to sheet Q-Allow or Area Inlet. Geographic Information: (Enter data in the blue cells):

Subcatchment Area = AcresPercent Imperviousness = %

NRCS Soil Type = A, B, C, or D

Slope (ft/ft) Length (ft)Overland Flow =Channel Flow =

Rainfall Information: Intensity I (inch/hr) = C1 * P1 / ( C2 + Tc ) ^ C3 Minor Storm Major StormDesign Storm Return Period, Tr = years

Return Period One-Hour Precipitation, P1 = inchesC1 =C2 =C3 =

User-Defined Storm Runoff Coefficient (leave this blank to accept a calculated value), C =User-Defined 5-yr. Runoff Coefficient (leave this blank to accept a calculated value), C5 =

Bypass (Carry-Over) Flow from upstream Subcatchments, Qb = 0.0 0.0 cfs

Total Design Peak Flow, Q = 4.3 11.1 cfs

<---FILL IN THIS SECTION OR…

FILL IN THE SECTIONS BELOW.<---

DESIGN PEAK FLOW FOR ONE-HALF OF STREET OR GRASS-LINED CHANNEL BY THE RATIONAL METHOD

Cornerstone RVVDP 1

Site is Urban

Site is Non-Urban

Show Details

Site Type: Street Inlets

Area Inlets in a Median

Flows Developed For:

Cornerstone DP 1 UD-Inlet_v3.14.xlsm, Q-Allow 4/28/2016, 9:48 AM

Project:Inlet ID:

Gutter Geometry (Enter data in the blue cells)Maximum Allowable Width for Spread Behind Curb TBACK = 12.4 ftSide Slope Behind Curb (leave blank for no conveyance credit behind curb) SBACK = 0.030 ft/ftManning's Roughness Behind Curb (typically between 0.012 and 0.020) nBACK = 0.020

Height of Curb at Gutter Flow Line HCURB = 6.00 inchesDistance from Curb Face to Street Crown TCROWN = 17.0 ftGutter Width W = 2.00 ftStreet Transverse Slope SX = 0.020 ft/ftGutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft) SW = 0.083 ft/ftStreet Longitudinal Slope - Enter 0 for sump condition SO = 0.000 ft/ftManning's Roughness for Street Section (typically between 0.012 and 0.020) nSTREET = 0.015

Minor Storm Major StormMax. Allowable Spread for Minor & Major Storm TMAX = 11.0 17.0 ftMax. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX = 4.0 8.5 inches

Allow Flow Depth at Street Crown (leave blank for no) check = yes

MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major StormMAJOR STORM Allowable Capacity is based on Depth Criterion Qallow = SUMP SUMP cfs

Major storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'

ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm)

Cornerstone RVVDP 1

(Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread)

Minor storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'

Cornerstone DP 1 UD-Inlet_v3.14.xlsm, Inlet In Sump 4/28/2016, 9:48 AM

Project =Inlet ID =

Design Information (Input) MINOR MAJORType of Inlet Inlet Type =Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal = 3.00 3.00 inches

Number of Unit Inlets (Grate or Curb Opening) No = 1 1 Water Depth at Flowline (outside of local depression) Ponding Depth = 4.8 6.8 inchesGrate Information MINOR MAJORLength of a Unit Grate Lo (G) = N/A N/A feetWidth of a Unit Grate Wo = N/A N/A feetArea Opening Ratio for a Grate (typical values 0.15-0.90) Aratio = N/A N/AClogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf (G) = N/A N/AGrate Weir Coefficient (typical value 2.15 - 3.60) Cw (G) = N/A N/AGrate Orifice Coefficient (typical value 0.60 - 0.80) Co (G) = N/A N/A

Curb Opening Information MINOR MAJORLength of a Unit Curb Opening Lo (C) = 10.00 10.00 feetHeight of Vertical Curb Opening in Inches Hvert = 6.00 6.00 inchesHeight of Curb Orifice Throat in Inches Hthroat = 6.00 6.00 inches

Angle of Throat (see USDCM Figure ST-5) Theta = 63.40 63.40 degreesSide Width for Depression Pan (typically the gutter width of 2 feet) Wp = 2.00 2.00 feetClogging Factor for a Single Curb Opening (typical value 0.10) Cf (C) = 0.10 0.10Curb Opening Weir Coefficient (typical value 2.3-3.7) Cw (C) = 3.60 3.60Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co (C) = 0.67 0.67

MINOR MAJOR

Total Inlet Interception Capacity (assumes clogged condition) Qa = 4.4 11.4 cfsInlet Capacity IS GOOD for Minor and Major Storms (>Q PEAK) Q PEAK REQUIRED = 4.3 11.1 cfs

INLET IN A SUMP OR SAG LOCATION

Cornerstone RVVDP 1

CDOT Type R Curb Opening

H-VertH-Curb

W

Lo (C)

Lo (G)

WoWP

Override Depths

Cornerstone DP 6 UD-Inlet_v3.14.xlsm, Q-Peak 4/28/2016, 9:46 AM

Worksheet Protected

Project:Inlet ID:

Design Flow: ONLY if already determined through other methods: Minor Storm Major Storm (local peak flow for 1/2 of street OR grass-lined channel): *QKnown = 2.3 5.9 cfs

* If you enter values in Row 14, skip the rest of this sheet and proceed to sheet Q-Allow or Area Inlet. Geographic Information: (Enter data in the blue cells):

Subcatchment Area = AcresPercent Imperviousness = %

NRCS Soil Type = A, B, C, or D

Slope (ft/ft) Length (ft)Overland Flow =Channel Flow =

Rainfall Information: Intensity I (inch/hr) = C1 * P1 / ( C2 + Tc ) ^ C3 Minor Storm Major StormDesign Storm Return Period, Tr = years

Return Period One-Hour Precipitation, P1 = inchesC1 =C2 =C3 =

User-Defined Storm Runoff Coefficient (leave this blank to accept a calculated value), C =User-Defined 5-yr. Runoff Coefficient (leave this blank to accept a calculated value), C5 =

Bypass (Carry-Over) Flow from upstream Subcatchments, Qb = 0.0 0.0 cfs

Total Design Peak Flow, Q = 2.3 5.9 cfs

<---FILL IN THIS SECTION OR…

FILL IN THE SECTIONS BELOW.<---

DESIGN PEAK FLOW FOR ONE-HALF OF STREET OR GRASS-LINED CHANNEL BY THE RATIONAL METHOD

Cornerstone RVVDP 6

Site is Urban

Site is Non-Urban

Show Details

Site Type: Street Inlets

Area Inlets in a Median

Flows Developed For:

Cornerstone DP 6 UD-Inlet_v3.14.xlsm, Q-Allow 4/28/2016, 9:46 AM

Project:Inlet ID:

Gutter Geometry (Enter data in the blue cells)Maximum Allowable Width for Spread Behind Curb TBACK = 12.4 ftSide Slope Behind Curb (leave blank for no conveyance credit behind curb) SBACK = 0.030 ft/ftManning's Roughness Behind Curb (typically between 0.012 and 0.020) nBACK = 0.020

Height of Curb at Gutter Flow Line HCURB = 6.00 inchesDistance from Curb Face to Street Crown TCROWN = 17.0 ftGutter Width W = 2.00 ftStreet Transverse Slope SX = 0.020 ft/ftGutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft) SW = 0.083 ft/ftStreet Longitudinal Slope - Enter 0 for sump condition SO = 0.000 ft/ftManning's Roughness for Street Section (typically between 0.012 and 0.020) nSTREET = 0.015

Minor Storm Major StormMax. Allowable Spread for Minor & Major Storm TMAX = 11.0 17.0 ftMax. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX = 4.0 8.5 inches

Allow Flow Depth at Street Crown (leave blank for no) check = yes

MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major StormMAJOR STORM Allowable Capacity is based on Depth Criterion Qallow = SUMP SUMP cfs

Major storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'

ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm)

Cornerstone RVVDP 6

(Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread)

Minor storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'

Cornerstone DP 6 UD-Inlet_v3.14.xlsm, Inlet In Sump 4/28/2016, 9:46 AM

Project =Inlet ID =

Design Information (Input) MINOR MAJORType of Inlet Inlet Type =Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal = 3.00 3.00 inches

Number of Unit Inlets (Grate or Curb Opening) No = 1 1 Water Depth at Flowline (outside of local depression) Ponding Depth = 4.5 6.5 inchesGrate Information MINOR MAJORLength of a Unit Grate Lo (G) = N/A N/A feetWidth of a Unit Grate Wo = N/A N/A feetArea Opening Ratio for a Grate (typical values 0.15-0.90) Aratio = N/A N/AClogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf (G) = N/A N/AGrate Weir Coefficient (typical value 2.15 - 3.60) Cw (G) = N/A N/AGrate Orifice Coefficient (typical value 0.60 - 0.80) Co (G) = N/A N/A

Curb Opening Information MINOR MAJORLength of a Unit Curb Opening Lo (C) = 5.00 5.00 feetHeight of Vertical Curb Opening in Inches Hvert = 6.00 6.00 inchesHeight of Curb Orifice Throat in Inches Hthroat = 6.00 6.00 inches

Angle of Throat (see USDCM Figure ST-5) Theta = 63.40 63.40 degreesSide Width for Depression Pan (typically the gutter width of 2 feet) Wp = 2.00 2.00 feetClogging Factor for a Single Curb Opening (typical value 0.10) Cf (C) = 0.10 0.10Curb Opening Weir Coefficient (typical value 2.3-3.7) Cw (C) = 3.60 3.60Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co (C) = 0.67 0.67

MINOR MAJOR

Total Inlet Interception Capacity (assumes clogged condition) Qa = 2.7 6.4 cfsInlet Capacity IS GOOD for Minor and Major Storms (>Q PEAK) Q PEAK REQUIRED = 2.3 5.9 cfs

INLET IN A SUMP OR SAG LOCATION

Cornerstone RVVDP 6

CDOT Type R Curb Opening

H-VertH-Curb

W

Lo (C)

Lo (G)

WoWP

Override Depths


STORM SEWER HYDRAULIC CALCULATIONS


BACKUP INFORMATION

FIRMETTE SOILS MAP

Hydrologic Soil Group—Adams County Area, Parts of Adams and Denver Counties, Colorado(River Valley Village (Thornton, CO))

Natural ResourcesConservation Service

Web Soil SurveyNational Cooperative Soil Survey

4/19/2016Page 1 of 4

4413

300

4413

400

4413

500

4413

600

4413

700

4413

800

4413

300

4413

400

4413

500

4413

600

4413

700

4413

800

505100 505200 505300 505400 505500 505600 505700 505800 505900

505100 505200 505300 505400 505500 505600 505700 505800 505900

39° 52' 30'' N10

4° 5

6' 2

8'' W

39° 52' 30'' N

104°

55'

48'

' W

39° 52' 10'' N

104°

56'

28'

' W

39° 52' 10'' N

104°

55'

48'

' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS840 200 400 800 1200

Feet0 50 100 200 300

MetersMap Scale: 1:4,290 if printed on A landscape (11" x 8.5") sheet.

MAP LEGEND MAP INFORMATION

Area of Interest (AOI)Area of Interest (AOI)

SoilsSoil Rating Polygons

A

A/D

B

B/D

C

C/D

D

Not rated or not available

Soil Rating LinesA

A/D

B

B/D

C

C/D

D


Soil Rating PointsA

A/D

B

B/D

C

C/D

D


Water FeaturesStreams and Canals

TransportationRails

Interstate Highways

US Routes

Major Roads

Local Roads

BackgroundAerial Photography

The soil surveys that comprise your AOI were mapped at 1:20,000.

Warning: Soil Map may not be valid at this scale.

Enlargement of maps beyond the scale of mapping can causemisunderstanding of the detail of mapping and accuracy of soil lineplacement. The maps do not show the small areas of contrastingsoils that could have been shown at a more detailed scale.

Please rely on the bar scale on each map sheet for mapmeasurements.

Source of Map: Natural Resources Conservation ServiceWeb Soil Survey URL: http://websoilsurvey.nrcs.usda.govCoordinate System: Web Mercator (EPSG:3857)

Maps from the Web Soil Survey are based on the Web Mercatorprojection, which preserves direction and shape but distortsdistance and area. A projection that preserves area, such as theAlbers equal-area conic projection, should be used if more accuratecalculations of distance or area are required.

This product is generated from the USDA-NRCS certified data as ofthe version date(s) listed below.

Soil Survey Area: Adams County Area, Parts of Adams andDenver Counties, ColoradoSurvey Area Data: Version 12, Sep 22, 2015

Soil map units are labeled (as space allows) for map scales 1:50,000or larger.

Date(s) aerial images were photographed: Aug 30, 2014—Sep18, 2014

The orthophoto or other base map on which the soil lines werecompiled and digitized probably differs from the backgroundimagery displayed on these maps. As a result, some minor shiftingof map unit boundaries may be evident.

Hydrologic Soil Group—Adams County Area, Parts of Adams and Denver Counties, Colorado(River Valley Village (Thornton, CO))



4/19/2016Page 2 of 4

Hydrologic Soil Group

Hydrologic Soil Group— Summary by Map Unit — Adams County Area, Parts of Adams and Denver Counties, Colorado(CO001)

Map unit symbol Map unit name Rating Acres in AOI Percent of AOI

NuA Nunn clay loam, 0 to 1percent slopes

C 8.3 11.0%

NuB Nunn clay loam, 1 to 3percent slopes

C 26.6 35.2%

ShF Samsil-Shingle complex,3 to 35 percent slopes

D 13.5 17.8%

UlC Ulm loam, 3 to 5 percentslopes

C 15.7 20.8%

UlD Ulm loam, 5 to 9 percentslopes

C 11.5 15.3%

Totals for Area of Interest 75.6 100.0%

Hydrologic Soil Group—Adams County Area, Parts of Adams and Denver Counties, Colorado River Valley Village (Thornton, CO)



4/19/2016Page 3 of 4

Description

Hydrologic soil groups are based on estimates of runoff potential. Soils areassigned to one of four groups according to the rate of water infiltration when thesoils are not protected by vegetation, are thoroughly wet, and receive precipitationfrom long-duration storms.

The soils in the United States are assigned to four groups (A, B, C, and D) andthree dual classes (A/D, B/D, and C/D). The groups are defined as follows:

Group A. Soils having a high infiltration rate (low runoff potential) when thoroughlywet. These consist mainly of deep, well drained to excessively drained sands orgravelly sands. These soils have a high rate of water transmission.

Group B. Soils having a moderate infiltration rate when thoroughly wet. Theseconsist chiefly of moderately deep or deep, moderately well drained or well drainedsoils that have moderately fine texture to moderately coarse texture. These soilshave a moderate rate of water transmission.

Group C. Soils having a slow infiltration rate when thoroughly wet. These consistchiefly of soils having a layer that impedes the downward movement of water orsoils of moderately fine texture or fine texture. These soils have a slow rate of watertransmission.

Group D. Soils having a very slow infiltration rate (high runoff potential) whenthoroughly wet. These consist chiefly of clays that have a high shrink-swellpotential, soils that have a high water table, soils that have a claypan or clay layerat or near the surface, and soils that are shallow over nearly impervious material.These soils have a very slow rate of water transmission.

If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter isfor drained areas and the second is for undrained areas. Only the soils that in theirnatural condition are in group D are assigned to dual classes.

Rating Options

Aggregation Method: Dominant Condition

Component Percent Cutoff: None Specified

Tie-break Rule: Higher

Hydrologic Soil Group—Adams County Area, Parts of Adams and Denver Counties, Colorado River Valley Village (Thornton, CO)



4/19/2016Page 4 of 4

preliminary drainage report - city of thornton … · i hereby certify that this report (plan) for...

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