Prepared For:

Larry H. Miller

LHM Thornton

Landmark

Towers

10289 Quivas Street

Thornton, Colorado

Anderson, Wahlen & Associates, Inc.

2010 North Redwood Road

Salt Lake City, Utah 84116

Phone: (801) 521-8529

Fax: (801) 521-9551

Project #: 14-116

Date: December 13, 2016

Utility Report

1/17/2017

Responsible Party Certification

“________ hereby certifies that the sewer and water systems for Landmark Towers 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 sewer and water system designed and/or certified by my engineer. I

understand that the City of Thornton reviews utility plans, but cannot, on behalf of Landmark Towers,

guarantee that final utility design review will absolve ________ and/or their successors and/or assigns of

future liability for improper design. I further understand that approval of the Plat and/or Development

Permit does not imply approval of my engineer’s utility design.”

Attest:

“I hereby certify that this report (plan) for the Final Utility Design of Landmark Towers 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 the Public and Private

Improvements for the Responsible Parties thereof. I understand that the City of Thornton does

not and shall not assume liability for utilities designed by others.”

XRegistered Pro fession al En g ineer

State of Co lo rado No. ____________________

XName of Respon sib le Party

XNotary Pu b lic

XAuth orized Sign atu re

Table of Contents GENERAL LOCATION MAP ............................................................................................................................. 1

PROPERTY LOCATION & DESCRIPTION ......................................................................................................... 2

PROPERTY LOCATION ................................................................................................................................ 2

DESCRIPTION OF PROPERTY ..................................................................................................................... 2

Basins and Pressure Zones. ........................................................................................................................... 2

MAJOR BASIN AND SUB-BASIN DESCRIPTION .......................................................................................... 2

DRAINAGE DESIGN CRITERIA ........................................................................................................................ 3

REGULATIONS ........................................................................................................................................... 3

DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS ...................................................................... 3

SYSTEM DESIGN CRITERIA ......................................................................................................................... 3

Conclusions ................................................................................................................................................... 4

COMPLIANCE WITH STANDARDS .............................................................................................................. 4

APPENDICES .................................................................................................................................................. 6

1

GENERAL LOCATION MAP

Landmark Towers: 10289 Quivas Street

Thornton, Colorado

2

PROPERTY LOCATION & DESCRIPTION

PROPERTY LOCATION

The proposed property is a Portion of the Northwest Quarter of Section 16, Township 2 South, and

Range 68 West of the 6th P.M. City of Thornton, County of Adams, in the State of Colorado. The address

of the site is 10289 Quivas Street, Thornton, Colorado.

The 6.55 acre site is currently undeveloped. The property is bound on the north by a Five Star Collision

Center-Auto Repair shop, to the east by Quivas Street, to the south by residential housing and a

developed commercial lot, and to the west the Alpine Glen Veterinary Clinic.

DESCRIPTION OF PROPERTY

Existing conditions of, the 6.55 acre, site consist primarily of undeveloped land covered by soil and

weeds. The site is relatively flat with the soils containing Platner loam and Ulm loam (Appendix I, Soil

Classification). Existing drainage of the site occurs from the west to the northeast side of the property.

The proposed project’s land use will be for Vehicle Service and Storage with a majority of the area

consisting of a parking lot. The site will consist a 4,010 square foot building, parking lot, and landscape

area located within the parking lot. A 10.0’ Public Service Utility Easement will be located south of the

proposed parking lot and a 10’ Gas Easement will be located through the north portion of the site

(Appendix II, Utility Plan)

BASINS AND PRESSURE ZONES

MAJOR BASIN AND SUB-BASIN DESCRIPTION

The site is located within Zone X (unshaded) of the FEMA floodplain, as determined by the Flood

Insurance Rate Map for Adams County, Colorado, Panel 294 and Map Number 08001C0294H, revised on

March 5, 2007 (Appendix III, FEMA FLOOD MAP).

The existing drainage for the site consist of overland sheet low to the northeast onto the neighboring

property. After construction, all storm water generated onsite will be collected into the site storm drain

network and ultimately detained in a detention basin located on the northeast side of the property.

Storm water will be detained and released to the City at a metered rate. The detention pond has a

3

Trickle Channel to direct low flows, which drains to an inlet/outlet structure before connecting to a curb

drain in Quivas Street.

With the majority of the site consisting of impervious area, the site increases runoff of 21.78 cfs for

existing conditions to 36cfs for the developed condition for the 100 year return period. These

calculations were determined by the Rational Method. This site was divided into roof area, landscaping

and hard surfaces to determine the runoff coefficient. Individual runoff coefficients of 0.13, 0.85 , and

0.9 were used for landscape, roof, and impervious surfaces respectively. The existing conditions of the

site contain soil and nuisance weeds with a low runoff coefficient of 0.13 and the developed condition,

containing 82% of impervious area, having a runoff coefficient of 0.77.

DRAINAGE DESIGN CRITERIA

REGULATIONS

It is not foreseen that there will be any deviations from the criteria. All waterlines and sanitary sewer

lines shall be constructed per the City of Thornton Standards and Specifications for the design and

Construction of Public and Private Improvements and all Applicable Master plans in effect at the time of

development.

DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS

To our knowledge there have been no previous utility studies (i.e., utility reports, project master plans,

etc.) done for this site in question, and no adjacent utility studies. All storm water produced on site will

be contained and will not drain to neighboring property.

SYSTEM DESIGN CRITERIA

The subject property lies within water zone 5, which has a High HGL equal to 5,675 and a Low HGL equal

to 5,675. The proposed finish floor of the building is 5524.00, which would provide an estimated static

pressure of 65 psi for both high and low. The peak water demand is anticipated to be 116 gpm. All

waterlines constructed shall be looped; in addition, the system pressure reducing valves shall be utilized

to keep the static pressure below 100 psi. A minimum static pressure of 40 psi shall be maintained for

the site. All Meters shall be sized in accordance with the adopted version on International Plumbing

Code and all adopted appendices in effect at the time of approval. Water meters are to be installed per

4

city standards and specifications. It will be the contractor's responsibility to install all items required.

The City of Thornton Standards and Specifications in Section 200 and 300 for water and sanitary sewer

design criteria shall be met. In other words, all piping materials shall be per local agency standards. All

utility piping shall be installed per manufacturer’s recommendations.

Conclusions

COMPLIANCE WITH STANDARDS

The LHM Thornton site located at 10289 Quivas Street is in compliance with the City of Thornton in the

State of Colorado Standards and Specifications Manual. The subject property lies within Water Zone 5

which contains a High HGL of 5,675 and a Low HGL of 5,675. The peak water demand is anticipated to be

116 gpm. The minimum static pressure of 40 psi is required and has an estimated static pressure of 65

psi.

All piping materials shall be per local agency standards, and installed per manufacturer’s

recommendations.

5

REFERENCES

City of Thornton (2012, October). City of Thornton – Standards and Specifications. Retrieved from

https://cityofthornton.net/government/citydevelopment/Pages/standards-specifications.aspx

United States Department of Agriculture, Natural Resources Conservation Service (n.d.). Web Soil

Survey. Retrieved from https://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx

FEMA (n.d.). FEMA Flood Map Service Center. Retrieved from http://msc.fema.gov/portal

6

APPENDICES

APPENDIX I – WEB SOIL SURVEY (SOIL CLASSIFICATION)

APPENDIX II – CIVIL UTILITY SHEET

APPENDIX III – FEMA FLOOD MAP

APPENDIX I - WEB SOIL SURVY (SOIL CLASSIFICATION)

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39° 5

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105° 0' 37'' W

39° 5

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9'' N

105° 0' 25'' W

39° 5

2' 5

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105° 0' 37'' W

39° 5

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N

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Hyd

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pera

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Soi

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vey

12/2

6/20

16P

age

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

PlC Platner loam, 3 to 5percent slopes

C 5.7 85.6%

UlD Ulm loam, 5 to 9 percentslopes

C 1.0 14.4%

Totals for Area of Interest 6.7 100.0%

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 receiveprecipitation from 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) whenthoroughly wet. These consist mainly of deep, well drained to excessivelydrained sands or gravelly sands. These soils have a high rate of watertransmission.

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

Group C. Soils having a slow infiltration rate when thoroughly wet. These 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 ofwater transmission.

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 claylayer at or near the surface, and soils that are shallow over nearly imperviousmaterial. 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 intheir natural condition are in group D are assigned to dual classes.

Hydrologic Soil Group—Adams County Area, Parts of Adams and Denver Counties, Colorado LHM - Thornton

Natural ResourcesConservation Service

Web Soil SurveyNational Cooperative Soil Survey

12/26/2016Page 3 of 4

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 LHM - Thornton

Natural ResourcesConservation Service

Web Soil SurveyNational Cooperative Soil Survey

12/26/2016Page 4 of 4

APPENDIX II - UTILITY PLAN

APPENDIX III - FEMA FLOOD MAP