F7_SWMP Report_APPROVED 2023-11-16.pdf

October 12, 2023 Template Version 1.2

Stormwater Management Plan for:

The Aurora Highlands Filing 7

North of 26th Avenue, East of Main Street and southwest of Warm Springs Avenue

Aurora, Colorado

80019

Owner/Operator(s):

Aurora Highlands, LLC

Carlo Ferreira

250 S Pilot Road

Las Vegas, NV 89119 carlo@thearourahighlands.com

Engineer Contact(s):

Matrix Design Group, Inc.

Jeff Killion, PE

707 17th Street, Suite 3150

Denver, CO 80202

303‐572‐0200 jeff_killion@matrixdesigngroup.com

SWMP Preparation Date: 8/22/2023

Estimated Project Dates:

Project Start Date: November 2023 Project Completion Date: April 2025

APPROVED FOR ONE YEAR FROM THIS DATE

City Engineer

Date

Aurora Water Department

Date cwoo Rectangle cwoo Stamp cwoo Date jfelling Typewritten Text 11/16/2023 jfelling Typewritten Text

223239ES1

2020-3021 02V, 02W

August 28, 2023

“THIS STORMWATER MANAGEMENT PLAN HAS BEEN PLACED IN THE CITY OF AURORA

FILE FOR THIS PROJECT AND HAS BEEN DETERMINED TO COMPLY WITH THE APPLICABLE

CITY OF AURORA STORMWATER MANAGEMENT CRITERIA. ADDITIONAL STORMWATER

MANAGEMENT, EROSION AND SEDIMENT CONTROL MEASURES MAY BE REQUIRED OF

THE OWNER OR HIS/HER AGENTS, DUE TO UNFORESEEN EROSION PROBLEMS OR IF THE

SUBMITTED PLAN DOES NOT FUNCTION AS INTENDED.”

“REVIEW OF THIS PLAN BY THE CITY OF AURORA SHALL NOT IMPLY THAT IT HAS BEEN

REVIEWED FOR COMPLIANCE WITH THE REQUIREMENTS SET FORTH BY THE STATE OF

COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT GENERAL PERMIT FOR

STORMWATER DISCHARGES ASSOCIATED WITH CONSTRUCTION ACTIVITY.”

“SEE APPROVED STORMWATER MANAGEMENT PLAN DESIGN DRAWINGS (SITE PLAN) FOR

SITE SPECIFIC BEST MANAGEMENT PRACTICES.”

Project Owner/Developer Signature Block I have reviewed the information contained within the Stormwater Management Plan and accept responsibility for the requirements set forth.

Permittee/Affiliation Date Matt Hopper, AACM District

Plan Preparer Signature Block I acknowledge my responsibility for the preparation of the Stormwater Management Plan.

CO Professional Engineer Date Jeff Killion, CO PE #40736

8/28/23

This electronic plan is a facsimile of the signed and sealed PDF plan

9-12-2310/31/23

10/31/23

October 31, 2023

Table of Contents

SECTION 1 SITE DESCRIPTION

i Site Location ii Description of Adjacent Areas

a) Nature and Purpose of Construction Activity

b) Construction Sequence

c) Area

d) Topography, Soils, and Rainfall Data

e) Existing Vegetation

f) Potential Sources of Pollution

g) Non Stormwater Discharges

h) Receiving Waters

i) Site Features and Sensitive Areas to be Protected

j) Other Applicable Federal, State or Local Programs, Regulations or Restrictions

SECTION 2 DESIGN DRAWINGS

SECTION 3 STORMWATER MANAGEMENT CONTROLS

a) SWMP Administrator and Important Contacts

b) Identification of Potential Pollutant Sources

c) BMPs for Stormwater Pollution Prevention

SECTION 4 FINAL STABILIZATION AND LONG TERM STORMWATER MANAGEMENT

a) Final Stabilization Measures

b) Seed Mix Information

c) Final Stabilization Notes

SECTION 5 INSPECTIONS AND MAINTENANCE

SECTION 6 PROBABLE COST FOR INSTALLATION OF BMPs

SECTION 7 CALCULATIONS MADE FOR THE DESIGN

SECTION 8 VARIANCE REQUESTS

REFERENCES

SWMP APPENDIX A – Floodplain Information SWMP APPENDIX B – Soils Information SWMP APPENDIX C – Probable Cost Forms SWMP APPENDIX D – Calculations SWMP APPENDIX E – Variance Request Details SWMP APPENDIX F – Vertical and General Construction Matrix

October 12, 2023

"Pursuant to Sections 138‐440 and 138‐442 of the Aurora Municipal Code, the Permittee shall locate, install, and maintain all Best Management Practices, including, but not limited to, erosion controls, sediment controls, drainage controls, and water quality BMPs as indicated in the approved Stormwater Management Plan (SWMP). The following notes are a requirement and shall be included in the SWMP narrative developed for this project and submitted for approval by the City. BMP installations shall be installed per the COA Standard Detail in effect at the time of installation or per the approved SWMP design drawing, a COA approved variance, or a COA approved design drawing plan amendment."

COA Stormwater Management Standard Notes

1. A City of Aurora Stormwater Quality Discharge Permit for Construction Activities must be issued by the City and executed by a COA Erosion Control staff prior to any earthwork activities.

An on‐site inspection will be conducted to verify the correct installation and adequacy of initial BMPs for the site. No earthwork, including clearing and grubbing, or demolition activities are to begin until the project site has passed an inspection and the City of Aurora Stormwater Quality Discharge Permit for Construction Activities has been executed. The Permittee is required to present the project’s CDPHE‐WQCD Stormwater Discharges Associated with Construction Activity Permit to the Inspector during the initial inspection. The Permittee shall designate a Stormwater Management Plan (SWMP) Administrator on the application for the City of Aurora Stormwater Quality Discharge Permit for Construction Activities. The SWMP Administrator will act as the project representative for any concerns or issues regarding environmental controls and stormwater management.

2. These requirements shall be the obligation of the Permittee, until such time as the Permit is properly closed, or otherwise allowed by the City to be voided, modified, transferred, re‐ assigned or replaced.

3. This SWMP narrative, the SWMP design drawings, and the Permitte’s inspection and maintenance records are all components of required record keeping and shall be kept on site at all times and updated as required. These and any other pertinent records shall be provided to the City when requested.

4. Any discrepancy between this SWMP and any other approved Stormwater Management Plan for this site shall require compliance with the more restrictive valid, approved plan.

5. Streets shall be constructed with Rough Cut Street Control measures, surface roughened or otherwise temporarily stabilized with rough cut street controls within seven (7) days of completion of grading in the appropriate phase. If paving is to occur within fourteen (14) days after final grading, rough cut street controls shall be waived.

6. Inspection and maintenance of erosion and sediment control Best Management Practices (BMPs) are the continuous obligations of the Permittee. BMPs shall be inspected at a minimum every seven (7) days and within 24‐hours after the end of a precipitation event that produces run‐off, and following snowmelt events. If a site is temporarily idle and no construction activities will occur during the 48 hours following a storm event, the post‐precipitation event (including

October 12, 2023 snowmelt) inspection shall be conducted prior to commencing construction activities on the site, but no later than 72 hours following the storm event. All necessary maintenance and repairs shall be initiated and completed on an on‐going basis, as features are required to operate continuously. Inspections may need to be conducted at a greater frequency than noted above, to ensure features and systems are operating adequately. Erosion and sediment control BMPs shall be maintained and functional for the entire duration of the project.

7. Ingress and egress vehicle access points onto disturbed areas shall be stabilized with Vehicle Tracking Control Pads (VTC) and shall be constructed with angular rock, 3” to 6” in size and to a depth of at least 9‐inches. The use of recycled asphalt or concrete is not permitted. The VTC shall be installed over a liner of non‐woven geotextile with a weight of at least 10 oz/yd2 and a grab tensile strength of at least 250 pounds. No dirt or other materials shall be placed on paved surfaces or curb flow lines to act as curb ramps. Only metal ramps or rock wattles may be used in the curb flow line.

8. Fugitive dust emissions resulting from grading activities and/or wind shall be controlled using reasonably available control technology as defined by the Colorado Department of Public Health and Environment.

9. All potential pollution sources on‐site shall be identified and control measures installed and practiced to minimize the likelihood of a release. Spill prevention controls shall be developed for the site with BMPs in place to respond to any spills, leaks or other releases.

10. Hydraulic mulching as a means to cover and protect seeding is not an acceptable means of applying mulch in the City of Aurora unless a previously installed irrigation system is used to aid germination and growth and where approved through variance. Hydraulic seeding is not permitted.

11. For all porous landscape detention facilities, in order to prevent clogging of filter medium, installation of the filtration system must be delayed until after the site is fully landscaped.

12. If stockpiles are located within 100 feet of a drainageway or a public storm sewer system, additional sediment controls such as temporary diversion dikes, silt fence, or sediment basin shall be required.

Page Intentionally Left Blank

SECTION 1 SITE DESCRIPTION

In this section, the preparer can gather some basic site information that will be helpful to the permittee later when you file for permit coverage.

– For more information, see City of Aurora Rules and Regulations Regarding Stormwater Discharges Associated with Construction Activities, current revision (also known as the Rules and Regs), Chapter 2

– Detailed information on determining your site’s latitude and longitude can be found at www.epa.gov/npdes/stormwater/latlong i Site Location

– Site location including, Section, township, range, and latitude/longitude to the nearest 15 seconds.

– Project street location or nearest major cross streets

– If applicable, specific acknowledgement that the land is currently, or will ultimately be owned or managed by the Parks, Recreation and Open Space Department.

Project/Site Name:The Aurora Highlands Filing 7 Subdivision

Project Street/Location: North of 26th Avenue, East of Main Street, and southwest of Warm Springs Avenue (future alignment)

City: Aurora State: CO ZIP Code: 80019

County or Similar Subdivision: Adams

Latitude/Longitude (Use one of three possible formats, and specify method)

Latitude: Longitude:

1. 39 º 45' 32'' N (degrees, minutes, seconds) 1. 104º 42' 18'' W (degrees, minutes, seconds)

2. _ _ º _ _ . _ _' N (degrees, minutes, decimal) 2. _ _ º _ _ . _ _' W (degrees, minutes, decimal)

3. N (decimal) 3. º W (decimal)

Method for determining latitude/longitude:

USGS topographic map (specify scale: ) EPA Web site GPS

Other (please specify):

Is this land currently or will it ultimately be owned or managed by COA Parks, Recreation, and Open Space Department? Yes No

CDPS Permit #*:

COA SWQ Permit #*:

*(This is the unique identifying number assigned to your project by your permitting authority after you have applied for coverage under the appropriate construction permit.)

ii Description of Adjacent Areas

– Provide a description of adjacent areas such as residential areas, roads, streams, lakes, etc, which might be affected by the proposed project’s land disturbing activity.

Provide adjacent area information

The project site is located north of 26th Avenue, East of Main Street, and southwest of Warm Springs Avenue (future alignment). The site lies within the northeast quarter of Section 30, Township 3 South, Range 65 West of the 6th Principal Meridian in the City of Aurora, County of Adams, State of Colorado. The site ecompases approximately 17.7 acres.

a) Nature and Purpose of Construction Activity Describe of the nature and purpose of the construction activity, note any vertical construction.

Construction activities on this site will include installation of watermain, sanitary sewer, storm sewer, sidewalks, and associated landscaping.

Residential Commercial Industrial Road Construction Linear Utility Overlot Grading Over-excavation Vertical Construction

Other (please specify):

b) Construction Sequence The proposed sequence for major activities should be described, including:

– An estimated project start

– An estimated project end date

– The sequence of major construction activities (Initial, interim, final or overlot grading, utilities, vertical, paving, over – excavation, etc.). This is expected to be a brief overview of the project as more detailed phasing information and specific BMPs will be addressed in later sections of the SWMP narrative report.

Estimated Project Start Date: 07/01/23

Estimated Project Completion Date: 11/01/24

Describe the major phases of construction:

Construction activities will occur during the same phase.

-Rough grading for this plan is part of The Aurora Highlands Phase 3 mass grading SWMP. It will be completed prior to the commencement of this SWMP.

-Prior to starting construction, initial BMPs will be placed to protect the surrounding areas and on any existing storm infrastructure on surrounding the site.

-Utility placement and utility excavation.

-Fine grading for sidewalks.

-Seeding and mulching around unpaved areas.

-Additional erosion control measures may be added at any time during construction if needed.

-Refer to contractor's schedule for detailed schedule of all construction activities.

c) Area The areas for the site should be described including any grading phasing which will need all of the information by phase, as well as for the overall project. This also includes overlot grading in different phases to achieve the outcome of the project. This may be required to be modified by the contractor with a phasing plan submittal.

– Provide estimates of the total area of the site and the sub area within the site expected to undergo clearing, excavation or grading.

– Include an estimate of the excavation and fill volumes involved during the proposed construction.

– Include an estimate of how excavation and fill will be phased.

– Include an estimate of over‐excavation areas and volumes (and type) and an estimate of offsite trucking volume (import and/or export).

Note: If exporting material to an area within the COA limits, the receiving site must have its own

SWMP and may be required to have its own COA Stormwater Quality Discharge Permit. If the export site is outside of COA limits, then the requirements of that local jurisdiction must be met and proof of a valid permit for the site will be required.

test

Total project area: 17.7 acres

Construction site area to be disturbed : 17.7 acres

Construction site over excavation area to be disturbed:

0.0 acres

Export/Import Volume

Phase Area Cut/Fill Net

11,000cy/60,000cy 49,000cy Fill

Description of phasing for sites disturbing more than 40 acres.:

Not applicable - site is less than 40 acres.

d) Topography, Soils, and Rainfall Data

– Provide a summary describing the soil, the soil type, and hydrologic soil group, permeability, texture, soil erosion potential, depth, soil structure, etc. and potential impacts of the soil type on the quality of any stormwater discharge from the site.

– A description of the topography of the site, existing site conditions, drainage patterns, and existing site slopes should also be included.

Note: A soils map showing the site limits and excerpts regarding the soils information shall be placed in the SWMP narrative report appendices.

Soil type(s):

Soil Mapping units include: PIB (Planter loam, 0 to 3 percent slopes) and TtB (Truckton loamy sand, 0 to 3 percent slopes).

Description Result Location of Occurrence

Highest Elevation:

Southeast corner of project

Lowest Elevation: 5493 Bottom of Swale on West Edge

Steepest Slope: 25% Within lots for overlot grading

Average Slope: 3% Within lots for overlot grading

Slopes (describe current slopes and note any changes due to grading or fill activities):

The Aurora Highlands Filing 7 subdivision area is generally sloping to the northwest through the project boundaries. The existing slopes range from 1% to 10%. The anticipated proposed slopes will range from 0.8% - 2.2% along roadways and paved surfaces, and 2% - 25% within landscape areas.

Drainage Patterns (describe current drainage patterns and note any changes dues to grading or fill activities):

The existing site drains northwest via a combination of sheet flow and First Creek Tributary W, which flows northwest through the project boundaries, to the existing Regional Detention and Water Quality Pond 8540 (per the Master Drainage Report) west of the site. Existing slopes range from 1% to 10%.

The Aurora Highlands Subdivision Filing Number 7 will be tributary to the existing Regional Detention and Water Quality Pond 8540. Improvements to this Regional Pond (hereinafter referred to as 8540 EURV Pond #2) will be completed with the Aurora Highlands Filing Number 9, prior to the construction of Filing 7. These improvements will be designed to upgrade the existing pond to provide EURV capacity for Filing 7 and other furture upstream developed areas, while maintaining an acceptable 100-year detention volume for its entire tributary area. Relevant excerpts from The Aurora Highlands Filing Number 9 Preliminary Drainage Report prepared by CAGE Civil Engineering have been included in Appendix D.

There are no known irrigation canals or ditches within the project boundary.

There are no regulated wetlands identified at this time within The Aurora Highlands Subdivision Filing Number 7 project boundary per the COE Appoved Jurisdictional Determination included in the Master Drainage Report

Normal Monthly Precipitation Table in Inches

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

0.51 0.49 1.28 1.93 2.32 1.56 2.16 1.82 1.14 0.99 0.98 0.63

Adapted from: http://www.ncdc.noaa.gov/oa/climate/online/ccd/nrmlprcp.html

Imperviousness and Runoff Coefficients:

― Calculate the percentage of impervious surface area before and after construction

― Calculate the runoff coefficients before and after construction.

Percentage impervious area before construction: 5 %

Runoff coefficient before construction (100 Yr): 0.22

Percentage impervious area after construction: 42.8 %

Runoff coefficient after construction (100 Yr): 0.54

e) Existing Vegetation

– Provide a description of the existing vegetation at the site and an estimate of the percent vegetative cover density prior to disturbance in an average square yard of the site. This requirement does not encompass hard surfaces or damaged areas. The consultant may have to evaluate vegetation from a nearby area if there has already been disturbance. There may also be drastically different vegetation in areas of the project or prairie dog issues, discuss as appropriate.

– A plan showing the existing major trees (4” diameter trunks and larger), tree masses, and shrub masses should be provided.

Existing Vegetation on the site:

Native vegetation and grasses/interim seeding

Pre-disturbance vegetation density:

The site is vegetated with native grasses and interim seeding.

Discuss tree protections and removals (reference detail for protection):

There are no trees within the project limits.

f) Potential Sources of Pollution

– Identify and list the proposed location and description of any potential pollution sources anticipated to be used during the project, such as portable toilets, vehicle fueling, grout/cement mixers, storage of fertilizers, paints or chemicals and stockpiles, etc.

– Materials of concern may include, but are not limited to, raw materials, fuels, metallic products, hazardous substances designated under Section 101(14) of the Comprehensive

Environmental Response, Compensation, and Liability Act (CERCLA), any chemical the facility is required to report pursuant to Section 313 of title III of the Superfund Amendments and

Reauthorization Act (SARA), fertilizers, pesticides, ash, slag, sludge concrete washout, paints, solvents, and waste piles.

Note: This is expected to be a brief list with detailed information being addressed in later sections of the SWMP narrative report.

Potential pollutants and sources to stormwater runoff:

Some of the pollutants listed below are potentially present on the site. Of the potential pollutants, the most likely candidates are paving operations, utility excavations, and soil stockpiling.

Trade Name, Material, or Operation

Stormwater Pollutants Potential Location

Bedding Stockpiles Sediment Entire site

Trade Name, Material, or Operation

Stormwater Pollutants Potential Location

Concrete Materials and Concrete Waste Management

Concrete Entire site

Concrete Curing Curing Compound Areas of Concrete Construction

Dewatering and Ponded Water Management

Ground Water and Ponded Water containing various other pollutants

Entire site

Form Oil and Concrete Forms Form Oil Building Construction

Grading Operations (clearing, excavating, etc)

Sediment Entire Site

Hazardous Wastes Fire Retardant, Acid Wash, Graffiti Prevention Liquid, Processed Water

Building Construction

Landscape Products Fertilizers, Herbicides, pesticides, fungicides, etc.

Entire Site

Masonry Cement, Grout, Masonry Mixers, Sand Stockpiles, etc Building Construction

Material Delivery Other Materials Entire site

Painters Paint, Primers, Stains, Glue Building Construction

Paving Operations Asphalt, Tar, Road Base, Lime Roadways

Sanitary Waste Management Sanitary Waste Construction and Staging Areas

Soil Stockpiling Sediment Entire site

Stabilized Staging/Haul Routes Sediment, Fuel, Oil Entire Site

Trash Debris, Bacteria, various chemicals, etc.

Construction and Staging Areas

Utility Excavations Sediment, Fuel, Oil Entire site

Vehicle and Equipment Maintenance, Cleaning, or Leaks

Fuel, Oil, Grease, Chemicals, Hydraulic Oil

Entire site

g) Non Stormwater Discharges Identify and list the location and description of any anticipated non‐stormwater components of the discharge, such as springs (State permit required), potable water for dust suppression, landscape irrigation return flow, pipeline dewatering (i.e. waterline flushing and testing) diverted stream flows, flows from wetlands, firefighting activities, hydrant blow‐offs, building power‐ washing where detergents are not used, construction dewatering of groundwater (State permit required),uncontaminated air conditioning or compressor condensate, foundation or footing drains where flows are not contaminated with process materials such as solvents (State permit may be required), or other discharges specifically authorized by a separate National Pollutant

Discharge Elimination Systems (NPDES) permit or a separate Colorado Discharge Permit System

(CDPS) permit etc. Discharges are those flows that are allowed to leave the site.

― Identify all allowable sources of non‐stormwater discharges that are not identified. The allowable non‐stormwater discharges identified might include those in the table below.

― Identify measures used to eliminate or reduce these discharges and the BMPs used to prevent those discharges from becoming contaminated.

Check if Applicable to Site List of Potential Non-Stormwater Discharges Management of Discharge

X Waters used to wash vehicles where detergents are not used Silt Fence, Inlet Protection, Stabilized Staging Area

X Water used to control dust Inlet Protection

X Potable water including uncontaminated water line flushings Inlet Protection

Routine external building wash down that does not use detergents

X

Pavement wash waters where spills or leaks of toxic or hazardous materials have not occurred (unless all spilled material has been removed) and where detergents are not used

Inlet Protection

Uncontaminated air conditioning or compressor condensate

Uncontaminated ground water or spring water

Foundation or footing drains where flows are not contaminated with process materials such as solvents

Uncontaminated excavation dewatering

X Landscape irrigation Silt Fence, Inlet Protection

X Potable water for firefighting activities Inlet Protection

Diverted channels or streams

Flows from wetlands

Sanitary sewer/plumbing line testing

Check if Applicable to Site List of Potential Non-Stormwater Discharges Management of Discharge

h) Receiving Waters List the name of all potential receiving water (s) and the size, type and location of any outfall. If the discharge is to a municipal storm sewer system, then provide the name of that system, the location of the storm sewer discharge, and the ultimate receiving water(s). State whether or not there are wetlands, the 100‐year floodplain status (i.e. if the site is within a floodway, near a flood plain or not within a flood zone), if the receiving water is impaired or not, and if there are any stream crossings proposed.

Note: Floodplain maps shall be provided in the SWMP narrative report appendices and shall show the site in relation to the floodplain.

― List the waterbody(s) that would receive stormwater from your site, including streams, rivers, lakes, and wetlands. Describe each as clearly as possible, such as Murphy Creek, a tributary to the Sand Creek, and so on. Indicate the location of all waters, including wetlands, on the site map.

― Note any stream crossings or stream diversions, if applicable.

― List the downstream storm inlets, storm sewer system or drainage system that stormwater from your site could discharge to and the waterbody(s) that it ultimately discharges to. It is preferred that the waterbodies are listed to a reservoir, Sand Creek, Cherry Creek or the South Platte.

― If any of the waterbodies above are impaired and/or subject to Total Maximum Daily Loads (TMDLs), please list the pollutants causing the impairment and any specific requirements in the TMDL(s) that are applicable to construction sites. Your SWMP should specifically include measures to prevent the discharge of these pollutants.

The site is within the Cherry Creek Drainage Basin: Yes No

The site is within the Aurora Reservoir Drainage Basin: Yes No

Description of receiving waters:

Existing Regional Detention and Water Quality Pond 8540 is online with and outfalls to First Creek Tributary W. First Creek Tributary W confluences with First Creek Tributary T downstream of the project site, which then confluences with First Creek, and eventually to the South Platte River.

Description of storm inlets and storm sewer systems:

Runoff will be directed to and collected in inlet drains and connect to the storm sewer and system and swales in Filing 7. The flows will be conveyed within the on-site streets.

Where the streets approach their conveyance capacity, inlets have been added to intercept surface flow into the storm sewer system, where it is routed to a forebay within 8540 EURV Pond #2.

Description of impaired waters or waters subject to TMDLs:

Not applicable

100- Year Floodplain Status:

No portion of the project is within the 100-year floodplain

Description of wetlands:

There are no wetlands within the project limits.

Other:

i) Site Features and Sensitive Areas to be Protected

– Describe unique site features including streams, stream buffers, wetlands, specimen trees, natural vegetation, steep slopes, or highly erodible soils that are to be preserved.

– Describe measures to protect these features.

– Include these features and areas on your SWMP design drawings.

j) Other Applicable Federal, State or Local Programs, Regulations or Restrictions

State any other regulations that are affecting the site (i.e. State CDPHE, Regulation 72, Consent

Decrees, etc).

1) Endangered Species Certification State whether or not there are any endangered species or critical habitats on or near the site. If so, then describe the impacts and the measures being taken to address that impact and supply documentation in the SWMP narrative report appendices.

Are endangered or threatened species and critical habitats on or near the project area?

Yes No

If yes, describe the species and/or critical habitat and provide reference to other documents as appropriate:

2) Historic Preservation State whether or not there are any historic sites on or near the site. If so, then describe the impacts and the BMP measures being taken to address that impact

Are there any historic sites on or near the construction site?

Yes No

If yes, describe or refer to documentation that determines the likelihood of an impact on this historic site and the steps taken to address that impact.

SECTION 2 DESIGN DRAWINGS

Approved design drawings shall be kept with the approved narrative report (this document) in the field and must be kept current. See COA Rules and Regs Chapter 3 for more information regarding

Living Documents. For most projects, a series of site maps is recommended. The first should show the undeveloped site and its current features. An additional map or maps should be created to show the developed site or for more complicated sites show the major phases of development.

– SWMP design drawings are required to indicate the types, locations, and extents of BMPs proposed for installation on the project site.

– For more information and requirements, see Rules and Regulations Regarding Stormwater Discharges Associated with Construction Activities, current revision (also known as the Rules and Regs), Chapter 2

SECTION 3 STORMWATER MANAGEMENT CONTROLS

This section shall describe the stormwater management controls that will be used to control pollutants in stormwater discharge during construction activity.

a) SWMP Administrator and Important Contacts

– List Contact names and phone numbers for the SWMP Administrator, alternates, owner, developer, etc that are known

– Copy as needed

Owner/Operator(s):

Aurora Highlands, LLC

Carlo Ferreira

250 S Pilot Road

Las Vegas, NV 89119

Telephone Number:

carlo@thearourahighlands.com

Area of Control (if more than 1 operator at site):

Project Manager(s) or Site Supervisor(s):

Company or Organization Name:

Name:

Address:

City, State, Zip Code:

Telephone Number:

Fax/Email:

SWMP Administrator Contact(s):

Company or Organization Name:

Name:

Address:

City, State, Zip Code:

Telephone Number:

This SWMP was Prepared by (the Colorado

Licensed Engineer):

Matrix Design Group, Inc.

Jeff Killion

707 17th Street, Suite 3150

Denver, CO 80202

303‐572‐0200

Jeff_Killion@matrixdesigngroup.com

Emergency 24‐Hour Contact (for site, not 911):

Name:

Address:

City, State, Zip Code:

Telephone Number:

Subcontractor(s):

Company or Organization Name:

Name:

Address:

City, State, Zip Code:

Telephone Number:

Other:

Name:

Address:

City, State, Zip Code:

Telephone Number:

Other:

Name:

Address:

City, State, Zip Code:

Telephone Number:

b) Identification of Potential Pollutant Sources All potential pollutant sources, including materials and activities, at a site must be evaluated for the potential to contribute pollutants to stormwater discharges.

– Identify and describe the sources of potential pollutants to stormwater discharges. At a minimum, each of the following sources and activities shall be evaluated for the potential to contribute pollutants to stormwater discharges.

– Numbers in [] brackets indicate the appropriate section to describe the BMPs to be used to address the potential pollutant source

Applicable to Site (Y, N, Maybe)

Sources of Potential Pollutants to

Stormwater Discharges

Applicable to Site (Y, N, Maybe)

Sources of Potential Pollutants to

Stormwater Discharges

Y

All disturbed and stored soils

(including borrow areas, stockpiles, haul routes, and over‐excavation)

[Section 3 c) 1, 2, and 3]

Y

Routine maintenance activities involving fertilizers, pesticides, detergents, fuels, solvents, oils, etc.

[Section 3 c) 4]

Y

Vehicle tracking controls and clean up [Section 3 c) 6]

On‐site waste management practices

(waste piles, liquid wastes, dumpsters, etc.) [Section 3 c) 7]

N

Management of contaminated soils

[Section 3 c) 4]

Concrete truck/equipment washing, including the concrete truck chute, pump truck primary and associated fixtures and equipment [Section 3 c)

7]

Y

Loading and unloading operations

(including access points and protection of existing BMPs)

[Section 3 c) 10]

N

Dedicated asphalt and concrete batch plants [Section 3 c) 5]

Y

Outdoor storage areas (building materials, fertilizers, chemicals, etc.)

[Section 3 c) 4]

Non‐industrial waste sources such as worker trash and portable toilets

[Section 3 c)7]

Y

Vehicle and equipment maintenance and fueling [Section 3 c) 4]

Other areas or procedures where potential spills can occur [Section 3

c) 4]

Y Significant dust or particulate generating processes (including haul

M

Stormwater or groundwater dewatering [Section 3 c) 9]

Applicable to Site (Y, N, Maybe)

Sources of Potential Pollutants to

Stormwater Discharges

Applicable to Site (Y, N, Maybe)

Sources of Potential Pollutants to

Stormwater Discharges routes, masonry mixing, and silos)

[Section 3 c) 2]

N

Power washing of building using detergents or other chemicals/solvents [Section 3 c) 4]

N

Building/vertical construction

(including paints, solvents, drywall, fire retardant, etc) [Section 3 c) 4, 7, 10]

c) BMPs for Stormwater Pollution Prevention This section of the SWMP narrative report shall include a narrative description of the appropriate controls and measures that will be implemented before, during and after construction activities at the project site to manage and control the runoff of pollutants.

The SWMP narrative report shall clearly describe the relationship between the phases of construction, and the implementation and maintenance of BMP controls and measures. For example, the report must indicate which controls will be implemented during each of the following phases of construction:

clearing and grubbing for perimeter controls, installation of initial BMPs, clearing and grubbing, overlot grading, installation of interim BMPs, site construction, utility construction, vertical construction, other pertinent construction phases, final grading, stabilization, removal of BMPs, and Permit closeout.

1) Structural Practices

– Clearly describe the initial/interim, post‐paving, and permanent structural site management practices to control erosion and sediment transport. Practices may include, but are not limited to: silt fences, diversion dikes, temporary slope drains, inlet protection, outlet protection, check dams, curb/rock socks, sediment control logs, compacted earthen berm, and terracing.

BMP Description: Interim Inlet Protection

Intended Use/Purpose: To reduce sediment entering the storm sewer system

Appropriate Installation Timing:

At time of construction of proposed inlets

Appropriate Removal Timing:

End of construction – once roadways are paved, and soils stabilized.

BMP Description: Sump Inlet Protection, On-Grade Inlet Protection

Intended Use/Purpose: To reduce sediment entering the storm sewer system

Appropriate Installation Timing:

At time of construction of existing and proposed inlets

Appropriate Removal Timing:

stabilized.

BMP Description: Drop / Area Inlet Protection

Intended Use/Purpose: To reduce amount of sediment entering storm sewer system

Appropriate Installation Timing:

At time of construction of proposed inlets

Appropriate Removal Timing:

stabilized

BMP Description: Seeding and Mulching

Intended Use/Purpose: To stabilize surface at completion of construction

Appropriate Installation Timing:

Completion of construction activity

Appropriate Removal Timing:

N/A

BMP Description: Concrete Washout

Intended Use/Purpose: To contain waste from concrete trucks and other washout operations. Reduce the amount of sediment entering the drainage system.

Appropriate Installation Timing:

Prior to any concrete construction activity beginning

Appropriate Removal

End of concrete construction

BMP Description: Silt Fence

Intended Use/Purpose: To reduce sediment leaving the site

Appropriate Installation Timing:

Prior to any construction activity beginning

Appropriate Removal

End of construction

BMP Description: Stabilized Staging Area

Intended Use/Purpose: Provide area for parking, storage, loading, unloading of material and equipment to reduce sediment and runoff leaving the site.

Appropriate Installation Timing:

Prior to any construction activity beginning

Appropriate Removal

BMP Description: Vehicle Tracking Control

Intended Use/Purpose: Reduce amount of sediment leaving the site via the tires of vehicles

Appropriate Installation Timing:

Prior to any construction activity beginning

Appropriate Removal

BMP Description: Rough Cut Street Control

Intended Use/Purpose: Reduce amount of sediment leaving site, reduce velocities and concentration of flows leaving the site.

Appropriate Installation Timing:

As roadway subbases are constructed

Appropriate Removal

Paving of roadway

BMP Description: Rock Socks

Intended Use/Purpose: To slow down concentrated flows within diversion ditches and aid in sediment removal

Appropriate Installation Timing:

As areas are disturbed during construction

Appropriate Removal Timing:

Installation of Storm Inlets and Storm Sewer System during future construction phase.

2) Non‐Structural Practices

– Clearly describe initial/interim, post‐paving, and permanent stabilization practices, including site specific scheduling of the implementation of these practices. Site plans should ensure that existing vegetation is preserved where possible and that all disturbed areas are stabilized. Non‐structural practices may include, but are not limited to:

temporary seeding, mulching, temporary sod stabilization, vegetative buffer strips, temporary landscaping, temporary erosion control blankets/matting, temporary soil retention matting, surface roughening, dust suppression, seasonal schedule, and preservation of mature vegetation.

BMP Description: Dust suppression / Wind erosion control

Intended Use/Purpose: Application of water when necessary to reduce erosion by wind

Appropriate Installation Timing:

This will begin when earthwork is underway

Appropriate Removal

When site is stabilized.

BMP Description: Good Housekeeping

Intended Use/Purpose: Maintain an orderly site to reduce trash and limit potential spills which would require cleanup

Appropriate Installation Timing:

Prior to any construction activity beginning

Appropriate Removal

3) Phase Construction Activity and BMP Implementation This section shall describe the relationship between the phases of construction, and the implementation and maintenance of BMP controls and measures. For example, indicate which controls will be implemented during each of the following phases of construction:

prior to clearing and grubbing for perimeter controls ( installation of initial BMPs), clearing and grubbing, overlot grading, installation of interim BMPs, site construction, utility construction, vertical construction, other pertinent construction phases, final grading, stabilization, removal of BMPs, and Permit closeout.

― Clearly describe the various phases of construction and the implementation of BMPs to be used during each phase. Examples of project phases may include, but are not limited to, demolition, clearing and grubbing, overlot grading, over‐excavation, road construction, utility installations, vertical construction, fine grading, and final stabilization. The description for a particular phase may have sub‐phases. For example, the overlot grading of an 80 acre site may have to describe multiple sub‐phases for the

40 acre disturbance limitation. Another example would be vertical construction phase may describe sub‐phases of the construction such as grading, foundations, framing, finishing, and stabilization. For more information, see Rules and Regs, Chapter 2, Section

2.2.1)

Note: Some construction information may need to be added once a contractor(s) are involved. See the

Manual and below for more information.

Phase Description: Initial Plan: Mobilization, Rough Grading

Duration of phase (start/end dates):

July 2023 – December 2023

BMPs Associated with the Phase:

Stabilized Staging Area, Vehicle Tracking Control, Inlet Protection, Dust Suppression, Silt Fence, Surface Roughening

Describe Temp/Final Stabilization for Phase:

Temporary seeding will be applied in appropriate areas

Phase Description: Final: Utility Installation, Fine Grading, Sidewalk Installation, Curb and Gutter Installation, Paving, Final Landscaping, Seeding and Mulching

Duration of phase (start/end dates):

December 2023 – November 2024

BMPs Associated with the Phase:

Inlet Protection, Drop / Area Inlet Protection, Rough Cut Street Control, Rock Socks, Concrete Washout Area, Seeding & Mulching

Describe Temp/Final Stabilization for Phase:

Inlet Protection, and Drop / Area Inlet Protection, will be installed as storm sewer is constructed. Temporary seeding will be applied in appropriate areas. Final Seeding & Mulching to stabilize area

a. Overlot Grading Specific Practices

Overlot grading specific practices should address items such as: surface roughening, blanketing, terracing, mulching, temporary seeding, permanent seeding, temporary sediment pond construction and removal, phasing, haul routes, disturbance limits, rough cut street controls, etc.

– Address haul routes may be designated on the SWMP updates and shall take into consideration drainage, erosion and sediment control BMPs, along with interim stabilization measures.

The scope for this project will include the construction of roadway and sidewalks, and installation of utilities. Overlot grading is anticipated. Specific location on haul routes, if needed, will be internal to the project limits and determined by the Contractor.

– Discuss interim stabilization may be provided via plan amendment by the contractor and the engineer at the Erosion Control Kick Off meeting. These measures shall be provided with timeframes and down gradient controls.

Repeat as needed.

Temporary drainage BMPs (diversion ditches, sediment traps or sediment basins) shall be maintained at all times.

– Discuss timing and procedural requirements for implementation, maintenance and removal of these items during this period of construction.

Temporary drainage BMPs will be maintained until the storm sewer system has been constructed and is on-line. At this time, these temporary BMPs will be removed.

b. Vertical and General Construction Requirements – See Appendix for Table of

Required Information

Staging areas change during construction regularly. Therefore, if “con/conex” boxes are to be utilized and if they are to include liquid pollutants, then a redundant BMP measure must be provided

Site drainage will need to be maintained during vertical construction. Review conditions to ensure that it will continue to work as shown during the grading/utility timeframes.

Provide redundant BMPs for generators and mobile concrete washouts to protect from fuel/hydraulic leaks

Continuously review the down gradient BMPs within the impervious and disturbed areas to ensure that conveyances, inlets and outlets are protected appropriately during this phase.

Areas of disturbance outside of the building envelope shall still require BMPs.

Continuously review the timing/phasing of the project to ensure the appropriate BMPs are implemented as construction continues. Deletion of BMPs shall require different measures to be implemented upon deletion.

BMPs for keeping impervious surfaces clean may need to be enhanced or added to as construction continues.

Review and implement BMP measures to control roof drainage. This becomes a point source and may cause extensive erosion on site.

Optional Section – To be included if the items in bullet points cannot be addressed elsewhere in this report.

A Plan Amendment from the contractor shall be required to be submitted to the engineer of record and City of Aurora Water Engineering Plans Reviewer three (3) business days prior to the Erosion

Control Kick‐Off Meeting. This submittal shall provide narrative information and the associated details required for vertical construction BMPs (structural and non‐structural) that will be implemented during this phase of construction.

Provide a mixing station detail/area for masonry/brick. If the site is going to bring in silos for masonry mixing, wind protection will be required to minimize the maximum extent practicable the dust from impacting adjacent buildings and streets.

Saw cutting station detail/area

Options for handling paints, solvents, glues (i.e. utilize the CWS or provide alternative)

Provide physical and procedural BMPs for clean up along the building during the installation of brick, stone or stucco

Access may be required around the building, defining a haul route may be necessary and denote stabilization needs on this proposed haul route

Address waste handling procedures for drywall, painters, carpet layers etc.

Stream Diversion Method

Cranes when access is required around the building and may impact BMPs, relocation may be required

4) Material Handling and Spill Prevention This section shall describe any procedures and locations for all practices implemented at the site that will be used to minimize impacts from identified potential pollutant sources. BMPs need to address many different pollutant sources that include, but are not limited to exposed storage of construction materials, liquid contaminants, contaminated soils management, fueling procedures, redundant measures for any spill or leak sources, and equipment maintenance procedures. Activities involving potential for spills shall have spill prevention and spill response procedures identified.

– Identify and describe how the sources of potential pollutants to stormwater discharges identified in Section 3.2 will be controlled through BMP selection and implementation. The information provided may address frequency, seasonal considerations, characteristics of the area and surface type, primary and secondary containment, proximity to drainageways and stormwater facilities.

BMP Description: Vehicle and Equipment maintenance and fueling

Intended Use/Purpose: Fueling by trained personnel to prevent spills, etc.

Location(s) Fueling will take place onsite.

BMP Description: Materials Staging and Stockpiling

Intended Use/Purpose: Materials will generally be stockpiled within the staging areas.

Stockpiled soils will be used as fill in areas requiring fill.

Location(s) Project wide

BMP Description: SPILL RESPONSE ‐Cleanup and Removal Procedures

Upon detection of any spill, the first action to be taken is to ensure personal safety. All possible ignition sources, including running engines, electrical equipment (including cellular telephones, etc.), or other hazards will be immediately turned off or removed from the area. The extent of the spill and the nature of the spilled material will be evaluated to determine if remedial actions could result in any health hazards, escalation of the spill, or further damage that would intensify the problem. If such conditions exist, a designated employee will oversee the area of the spill and the construction SWMP

Administrator will be notified immediately.

The source of the spill will be identified and if possible the flow of pollutants stopped if it can be done safely. However, no one should attend to the source or begin cleanup of the spill until ALL emergency priorities (fire, injuries, etc.) have been addressed.

Small Spills Small spills (usually <5 gallons) consist of minor quantities of gasoline, oil, anti‐freeze, or other materials that can be cleaned up by a single employee using readily available materials.

The following procedures should be used for clean‐up of small spills:

a. Ensure personal safety, evaluate the spill, and if possible, stop the flow of pollutants.

b. Contain the spread of the spill using absorbents, portable berms, sandbags, or other available measures.

c. Spread absorbent materials on the area to soak up as much of the liquid as possible and to prevent infiltration into the soil.

d. Once the liquids have been absorbed, remove all absorbents from the spill and place the materials in a suitable storage container. On paved areas, wipe any remaining liquids from the surface and place the materials in a storage container. Do not spray or wash down the area using water. For

NOTE: IN CASE OF FIRE, EVACUATE ALL PERSONNEL FROM THE IMMEDIATE AREA, RENDER FIRST

AID TO ANYONE WHO IS INJURED, AND DIAL 911 IMMEDIATELY. TAKE APPROPRIATE STEPS TO

PROTECT HUMAN LIFE AND TO CONTROL FIRES FIRST. SPILL CONTROL IS SECONDARY.

open soil areas, excavate any contaminated soil as soon as possible and place the soil in a suitable storage container. All materials will then be transported off‐site for disposal.

e. If immediate transfer and storage of the contaminated soil is not practical, excavate and place the contaminated soil on a double thickness sheet of 3‐mil or higher polyethylene film. In addition, a small berm should be formed around the outer edges of the soil stockpile, underneath the polyethylene film, to ensure that contaminants are not washed from the site during precipitation events and that materials do not seep through the berm.

f. Record all significant facts and information about the spill, including the following:

Type of pollutant

Location

Apparent source

Estimated volume

Time of discovery

Actions taken to clean up spill

g. Notify the SWMP Administrator of the spill and provide the information from Item f. The SWMP

Administrator will then contact the City of Aurora Erosion Control Staff.

Medium to Large Spills Medium to large spills consist of larger quantities of materials (usually >5 – 25 gallons) that are used on site that cannot be controlled by a single employee. Generally, a number of facility personnel will be needed to control the spill and a response may require the suspension of other facility activities.

The following procedure shall be used for the cleanup of medium to large spills:

a. Ensure personal safety, evaluate the spill, and if possible, stop the flow of pollutants.

b. Immediately dispatch a front‐end loader or similar equipment to the spill and construct a berm or berms down gradient of the spill to minimize the spread of potential pollutants. On paved surfaces, portable berms, sandbags, booms, or other measures will be used to control the lateral spread of the pollutants.

c. When the spread of the spill has been laterally contained, contact the SWMP Administrator or designated facility employee and provide them information on the location, type, and amount of spilled material, and a briefing on the extent of the spread and measures undertaken to contain the contaminants.

d. Depending on the nature of the spill, mobilize additional resources as needed to contain the contaminants.

e. Cleanup will commence when the lateral spread has been contained and the notification to the

SWMP Administrator has been made.

f. Freestanding liquid will be bailed or pumped into…