HomeMy WebLinkAboutReports - Erosion Control - 05/18/2016EROSION CONTROL REPORT / STORMWATER MANAGEMENT PLAN
FOR
HARMONY COTTAGES
Prepared by:
Interwest Consulting Group
1218 West Ash, Suite A
Windsor, Colorado 80550
Phone: 970.674.3300
Fax: 970.674.3303
Prepared for:
Habitat for Humanity
4001 S. Taft Hill Road
Fort Collins, CO 80525
(970)-223-4522
May 18, 2016
May 18, 2016
Mr. Jesse Schlam
City of Fort Collins Stormwater
700 Wood Street
Fort Collins, CO 80522-0580
RE: Erosion Control Report / Stormwater Management Plan
Harmony Cottages
Dear Jesse,
I am pleased to submit for your review and approval, this Erosion Control Report / Stormwater
Management Plan for the Harmony Cottages project. This report provides the City with an
erosion control plan for the proposed development that addresses the topics outlined in the City
Erosion Control Report Requirements. This plan mimics the State of Colorado General Permit
and Stormwater Management Plan requirements.
I appreciate your time and consideration in reviewing this submittal. Please call if you have any
questions.
Sincerely, Reviewed By:
Skylar Brower, P.E. Robert Almirall, P.E.
Colorado Professional Colorado Professional
Engineer No. 44248 Engineer No. 33441
TABLE OF CONTENTS
1. INTRODUCTION .................................................................................................................... 1
2. SITE DESCRIPTION ............................................................................................................... 1
3. BMPS FOR STORMWATER POLLUTION PREVENTION ................................................ 5
3.1. Erosion and Sediment Controls ........................................................................................ 5
3.2 Materials Handling and Spill Prevention ......................................................................... 7
4. STORMWATER MANAGEMENT CONTROLS .................................................................. 9
4.1. SWMP Administrator ....................................................................................................... 9
4.2. Identification of Potential Pollution Sources ................................................................... 9
5. FINAL STABILIZATION AND LONG TERM STORMWATER MANAGEMENT ......... 11
6. INSPECTION AND MAINTENANCE ................................................................................. 11
6.1. City of Fort Collins Standard Erosion and Sediment Control Notes ............................. 12
6.2. City of Fort Collins Erosion Control Security Calculations ........................................... 14
7. SWMP IMPLIMENTATION ................................................................................................. 15
APPENDIX A—BMP DETAILS ................................................................................................. P
APPENDIX B—EROSION CONTROL PLAN AND SITE MAP .......................................... Q
APPENDIX C—CONSTRUCTION SEQUENCE .................................................................... R
APPENDIX D—SOIL INFORMATION .................................................................................... S
LIST OF FIGURES & TABLES
Figure 1--Vicinity Map ................................................................................................................... 2
Table 6.1 – Erosion Control Cost Estimate………………………...……………………………14
1
1. INTRODUCTION
The primary purpose of preparing and maintaining a stormwater management plan is to
improve the health and quality of the State's urban waterways. The preparation and
maintenance of the plan will contribute to this objective by facilitating an approach to
stormwater management, establishing a program of actions to be used during construction
activities, and describing stormwater management controls and various Best Management
Practices (BMPs) necessary to reduce erosion, sediment and pollutants in stormwater
discharge.
Information concerning the State of Colorado General Permit and Stormwater
Management Plan are not included in the appendices of this report. The site is over one
acre and will require a SWMP permit, which will be the responsibility of the Contractor.
2. SITE DESCRIPTION
The Harmony Cottages development is located in the Southwest Quarter of Section 34,
Township 7 North, Range 69 West of the 6th Principal Meridian in the City of Fort
Collins, Larimer County, Colorado. The project site is located in the southeast corner of
Harmony Road (County Road 38E) and Taft Hill Road.
The site is approximately 4.45 acres, and currently consists of open space and is sparsely
vegetated with native plants and grasses. The existing site is approximately 70-75%
vegetated. The site is bounded by Harmony Road on the north and east, Taft Hill Road
on the west, and The Overlook at Woodridge Fourth Filing on the south. See Figure 1 on
then next page for the vicinity map.
The project is a site development of a Habitat for Humanity neighborhood. The site will
be designed for single family and duplex units with a main private drive and alley ways to
access each unit.
2
Figure 1--Vicinity Map
All concrete curb and gutter areas are designed with a minimum slope of 0.5%, all asphalt
paved areas are designed with a minimum slope of 2.0%, all concrete paved areas are
designed with a minimum slope of 0.5%, and all grassed areas are designed with a
minimum slope of 2.0%. The grass swale along the southern property line has areas that
are less than 2.0%, so an underdrain system has been designed to prevent standing water.
Side slopes in grassed areas are graded to a maximum slope of 4:1.
Runoff from the southern portion of the site is conveyed via overland flow to proposed
grass swale that runs west to east along the southern property boundary. This grass swale
discharges into the proposed rain garden located in the southeast corner of the site.
Runoff from the northern portion of the site is conveyed via curb and gutter to the rain
3
garden located at the southwest corner of the intersection of driveway and Harmony
Road. Both rain gardens discharge to existing storm drain inlets located on Harmony
Road.
Existing soil types on site as classified by the NRCS Soil of Larimer County are classified
as Altvan-Satanta Loams, and Fort Collins Loam. Please refer to Table 2.1 for additional
soil characteristics.
Table 2.1: Harmony Cottages On-site Soil Characteristics
Soil Type
Percent of
Site
Hydrologic
Soil Group
K
Factor1
Wind
Group2
Altvan-Satanta Loam 88.5 B 0.28 5
Fort Collins Loam 11.5 C 0.43 5
1K factors range from 0.02 to 0.69. The higher value, the more susceptible the soil is to sheet and
rill erosion by water.
2Soils assigned to wind group 1 are the most susceptible to wind erosion, soils assigned to wind
group 8 are the least susceptible.
Overall, the soils on site can be classified as moderately erodible. Please refer to
Appendix D for the on-site soil information from the NRCS Soil Survey of Larimer
County.
This project is not within any FEMA or City of Fort Collins mapped floodway, therefore
Floodplain Regulations Compliance is not required.
The anticipated sequence of construction shall progress as follows:
1) Installation of perimeter erosion control measures (silt fence along the north
existing sidewalk, gravel bags and inlet protection at the existing inlets located on
Harmony Road. Other measures as required for the permit will be constructed
throughout).
2) Sidewalk removal, clearing, stripping and grading
3) Utility installation
4) Sub-grade preparation for the buildings, walks, and drives
4
5) Curb, gutter and sidewalks
6) Paving
7) Building construction (this may occur simultaneously with items 5 through 7)
8) Final grading and landscaping. All disturbed ground will be impervious (concrete,
asphalt, or building), seeded and mulched, sodded or xeriscaped to permanently
stabilize the site. Both rain gardens will be completed at this time as well.
Table 2.2: Sub-Basin Characteristics
The run-off coefficients associated with this project for onsite Sub-Basins are as follow:
Sub-Basin Area (AC) C10 C100
A 1.65 0.53 0.66
B 2.24 0.63 0.79
C 0.12 0.84 1.00
D 0.20 0.48 0.60
E 0.21 0.47 0.58
OS-10 0.80 0.70 0.88
OS-21 0.34 0.72 0.90
OS-1 0.40 0.11 0.13
OS-2 0.12 0.13 0.16
OS-3 0.49 0.58 0.73
No known sources of pollution currently exist on this site. Potential pollutant sources
brought onto the site during construction will be discussed (along with spill prevention)
in Section 3.2 below. The anticipated non-stormwater components of discharge with this
project are landscape irrigation return flows. All of the stormwater runoff from the site is
conveyed to the existing stormwater conveyance system in Harmony Road which passes
to the existing concrete lined drainage channel north of Seneca Drive and then to the
existing regional detention pond located adjacent to Webber Middle School.
5
3. BMPS FOR STORMWATER POLLUTION PREVENTION
3.1. Erosion and Sediment Controls
Structural Practices: Structural practices for the site will consist mainly of silt fence,
vehicle tracking control pad, concrete washout area, inlet protection, gravel bags, and
erosion log which are described in detail in the following paragraphs. Detail drawings of
these BMPs are also included in Appendix A. These BMPs are expected to change as the
construction progresses and it is the responsibility of the contractor to ensure appropriate
BMPs are in place and/or removed at the appropriate time in the construction sequence.
All temporary and permanent erosion and sediment control practices must be maintained
and repaired as needed to assure continued performance of their intended function. All
BMPs shall be inspected and repaired or replaced as indicated in Section 6 and as
required to satisfy the conditions of the Permit.
Silt fence prevents sediment from leaving the site during a runoff event by collecting the
deposits along the fence line while allowing the storm water to seep through. Silt fence
shall be placed along the back of the north existing sidewalk to prevent sediment
transport into the existing inlets located on Harmony Road. Silt fence shall be inspected
and maintained after every rainfall event that produces runoff. Sediment must be removed
and rocks replaced. Silt fence shall be installed prior to any work commencing on-site.
Vehicle tracking pad is intended to trap mud and sediment within coarse grain material
and provide clean access to public roadways. Wherever construction vehicle access routes
intersect paved public roads a vehicle tracking control pad shall be installed to minimize
the transport of sediment (mud) by runoff or vehicles tracking onto the paved surface.
Pads shall be maintained and refurbished when necessary to obtain their intended result.
Concrete washout area is intended to contain washout liquids and solids that result from
the cleaning of concrete trucks and pumps. Washouts should be placed near the area
where the concrete is being poured.
Inlet protection prevents sediment from entering storm drainage systems prior to
permanent stabilization of the disturbed site area via ponding and settling of sediment.
Gravel bags shall be used as flowline protection for existing curb and gutter along
Harmony Road. Inlet protections shall be placed at new inlets and existing inlets near the
site. Storm sewer inlet protection must be inspected and maintained after every rainfall
6
event that produces runoff.
Erosion logs shall be implemented as sediment control and velocity reduction in existing
and proposed swales, as well as toe of slopes as necessary. Erosion logs shall be installed
immediately upon completion of over-lot grading and/or the installation of the proposed
swales.
Non-Structural Practices: All low sloped areas exposed during land disturbing activity
(stripping, grading, utility installations, stockpiling, filling, etc.) shall be kept in a
roughened condition by ripping or disking along land contours until mulch, vegetation or
other permanent erosion control is installed.
All exposed steep sloped areas exposed during land disturbing activity (stripping,
grading, utility installations, stockpiling, filling, etc.) shall have slope protection. The
contractor shall use a "tracked" vehicle, run perpendicular to slope to inhibit rill/gully
erosion; the contractor may use other windrow-type methods as necessary.
No soil shall remain exposed by land disturbing activity for more than thirty (30) days
before required temporary or permanent erosion control (seed/mulch, landscaping, etc.) is
installed.
THE CONTRACTOR SHALL ADD ANY AND ALL BMP’S AND DETAILS
NEEDED FOR SEDIMENT/EROSION CONTROL.
7
3.2 Materials Handling and Spill Prevention
Potential impacts from significant materials and their handling are as follows:
Chemicals, cleaning substances, and petroleum products related to the construction will
be stored within the construction trailer or storage shed where it will not be in contact
with precipitation. No storage of these materials will be allowed outside.
Fueling and maintenance of equipment shall take place at the construction staging area.
Fueling will be accomplished with fueling trucks on an as needed basis. Absorbent (kitty
litter) will be in the construction trailer and applied on any spill immediately and the dry
material disposed of properly and legally.
All construction waste shall be disposed of in the available dumpsters throughout the
workday. Liquid wastes will be hauled off site and disposed of properly and legally.
Any cleaning or maintenance of small equipment will be required to be done within a
containment device (horse trough or small “kiddy pool”) and the liquid disposed of
properly and legally.
In the event of any spill, the SWMP Administrator shall be immediately notified.
Spills can be broken into three categories. Their definitions and the procedures required
to address the spills are as follow:
Minor Spill – A spill generally of less than 5 gallons which is unlikely to reach adjacent
waters (i.e. equipment leak).
Procedure:
a. Stop the source of the spill.
b. Contain the spillage.
c. Contact the SWMP Administrator.
d. Clean up the spill with on-site absorbent material (kitty litter)
e. Dispose of the dry material properly or legally.
f. Document the spill and the response in the SWMP including dates
and times – verify that the pollutants are completely cleaned up.
g. Include incident in the following training meeting.
h. Provide information to the City of Fort Collins at the next regular
inspection.
8
Significant Spill – A spill of pollutants or oils of any size that will likely or has reached
adjacent waters, may endanger health or the environment, or which may exceed a water
quality standard.
Procedure:
a. Stop the source of the spill.
b. Contain the spillage.
c. Contact the SWMP Administrator.
d. Clean up the spill with on-site absorbent material (kitty litter)
e. Dispose of the dry material properly or legally.
f. Document the spill and the response in the SWMP – verify that the
pollutants are completely cleaned up.
g. Notify the City of Fort Collins (970) 221-6700 and the Colorado
Department of Public Health and Environment spill reporting line
(877) 518-5608 of the spill.
h. Notify the same two entities above with a written submission
(outlined within the permit) within 5 calendar days.
i. Include incident in the following training meeting.
Hazardous Spill – A spill of a dangerous substance requiring expert cleanup.
Procedure:
a. Secure the area – do not approach the spill.
b. Offer first aid to any injured parties.
c. Call 911 and describe the nature of the spill and any injuries.
d. If possible, isolate downstream areas from the spill (for example,
cover an inlet that is downstream and a safe distance from the spill
with plastic and soil).
e. Contact the SWMP Administrator.
f. Document the spill and the response in the SWMP
g. Notify the City of Fort Collins (970) 221-6700 and the Colorado
Department of Public Health and Environment spill reporting line
(877) 518-5608 of the spill.
h. Notify the same two entities above with a written submission
(outlined within the permit) within 5 calendar days.
i. Include incident in the following training meeting.
9
4. STORMWATER MANAGEMENT CONTROLS
4.1. SWMP Administrator
The Local Contact and SWMP Administrator is (INSERT CONTACT NAME,
POSITION, COMPANY, AND PHONE NUMBER).
(INSERT CONTACT) will be responsible for developing, implementing, maintaining,
and revising the SWMP. (INSERT CONTACT) will also be responsible for required
inspections and coordinating and documenting changes or repairs resulting from
inspections. (INSERT CONTACT) will be responsible for the training and enforcement
aspects of the SWMP and he is the first point of contact for any stormwater issues.
4.2. Identification of Potential Pollution Sources
The permit identifies 13 potential sources that must be evaluated for their potential to
contribute pollutants to stormwater discharge. These items have been evaluated below
for this project:
1) Disturbed and stored soil – YES – The construction will require that areas
be disturbed exposing soil including paving, slope construction, utility
installation, and construction of buildings as shown on the plans. BMPs
will include silt fence, inlet protection on existing and proposed inlets,
erosion logs, minimizing disturbance of existing vegetation and hard
surfaces, and slope roughening and tracking of slopes after disturbance and
prior to landscaping, paving, or building construction will be
implemented.
2) Vehicle tracking of sediment – YES –BMPs will include a policy that
vehicles be clean prior to entering the site and, if they become muddy
during construction or earthwork activities, mud is removed by hand from
the vehicle prior to departing the site in an area near the vehicle tracking
pad. Any soil that is removed is to be disposed of in the trash dumpster by
scraping or sweeping. Any muddy vehicle will use the vehicle tracking pad
prior to leaving the site.
3) Management of contaminated soil – NO – Soil borings do not indicate any
existing contamination. If contaminated soil is encountered, it shall be
disposed of in an approved manner as outlined by the department of public
health and environment.
4) Loading and unloading operations – YES – Chemicals and petroleum
products will be brought to the site. Anytime these are being transported,
they will be in a sealed container.
5) Outdoor storage activities – YES – Inert materials such as wood and stone
will be stored outside and will likely be covered with tarps or plastic, but
10
are not pollutant sources and are not covered by the permit. Chemicals
and petroleum products will be stored within the construction trailer or
storage shed. Cement and mortar bags (if not contained in a vehicle or
storage shed) will be completely covered with plastic to avoid contact with
precipitation.
6) Vehicle and equipment maintenance and fueling – YES – Vehicle
maintenance and fueling will take place near the exterior streets
surrounding the project site (a minimum of 50’ away from any existing
inlet). No fuel will be stored on site; a fuel truck will deliver fuel directly
to equipment as needed. The largest risk to stormwater with this operation
is pollutants being spilled in the existing asphalt. Absorbent (kitty litter)
will be available on site and applied on any spill immediately and the dry
material disposed of properly and legally.
7) Significant dust or particulate generating processes – YES –Most of the
site will be exposed from the grading of the project. In order to control the
dust generated during construction, a water truck will be available on site
at all times or an acceptable onsite water source will be established. The
disturbed ground will be watered as needed to control dust from leaving
the site.
8) Routine maintenance activities involving fertilizers, pesticides, detergents,
fuels, solvents, oils, etc. – YES – Fertilizers and pesticides will not be
used. Any cleaning or maintenance of small equipment will be required to
be done within a containment device (horse trough or small “kiddy pool”
and the liquid disposed of properly and legally.
9) On-site waste management – YES – The building and site construction
(access drive, underground utilities, and concrete walks) will result in
construction waste. A dumpster for trash and a dumpster for bulk recycling
will be on the site. Waste will be hauled to the dumpsters by hand or in
loaders. Dumpsters will be hauled off as needed. Dumpsters shall be
located a minimum of 50 feet away from any existing inlet on site. No
construction waste will be left outside overnight. No construction debris
(including broken concrete) may be buried on the site.
10) Concrete truck/equipment washing – YES – A concrete washout will be
provided on site. This will be used for trucks and for any masonry/
concrete tools. The concrete washout shall be located a minimum of 50
feet away from any existing inlet on site.
11) Dedicated asphalt of concrete batch plants – NO – None on this project.
12) Non-structural waste sources such as worker trash and portable toilets –
YES – Trash dumpster will be available for worker’s trash and will be
located near the construction trailer. Portable toilets will be on site near the
construction trailer. All portable toilets and trash dumpsters shall be
located a minimum of 50 feet away from any existing inlet on site. All
portable toilets will be staked to the ground in order to prevent tipping.
13) Other areas where potential spills can occur – NO – The above 12 items
11
are adequate for the anticipated construction process.
CONTRACTOR TO UPDATED THE ABOVE INFORMATION WITH EXACT
LOCATIONS OF THE CONSTRUCTION TRAILER, VEHICLE TRACKING PAD,
CONCRETE WASHOUT, DUMPSTERS, AND PORTABLE TOILETS PRIOR TO
COMMENCEMENT OF CONSTRUCTION AND UPDATED AS NECESSARY
THROUGHOUT THE CONSTRUCTION SEQUENCE.
5. FINAL STABILIZATION AND LONG TERM STORMWATER
MANAGEMENT
Final stabilization shall be considered achieved once all proposed site improvements are
in place, all vegetation is established, all temporary BMPs are removed, and that
downstream conveyances are inspected and certified to be clean and free from any
construction debris resulting from the construction. Areas controlled by grass sod will be
considered established upon the completion of sod installation. Areas of seeding will be
considered established at 70% of original coverage.
INSPECTION AND MAINTENANCE
Site inspections will be performed to effectively address maintenance, repair, and
adequacy of BMPs. The site inspections will be performed by the SWMP Administrator
or his designee a minimum of once every fourteen (14) calendar days on active
construction sites and within 24 hours after a significant storm event (event causing
erosion). As part of the site inspections the inspector will keep documentation of all
inspections and BMP maintenance, including updated Site Maps indicating new BMPs or
the removal of BMPs since the previous inspection. Blank Site Maps will be utilized and
will be redlined by the SWMP Administrator throughout construction to note all BMPs,
pollutant sources, storage locations, etc.
Any maintenance, repair, or necessary installation of BMPs that are noted during the
inspection must begin immediately. The modifications shall be noted in the SWMP and
the action taken as a result of the inspection shall be noted and certified on or attached to
the original inspection report (date and time that the repair or change was started and
12
finished and a certification that it was done properly).
5.1. City of Fort Collins Standard Erosion and Sediment Control Notes
1) The City Stormwater Department erosion control inspector must be notified at
least 24 hours prior to any construction on this site.
2) All required BMPs shall be installed prior to any land disturbing activity
(stockpiling, stripping, grading, etc.). All of their required erosion control
measures shall be installed at the appropriate time in the construction sequence as
indicated in the approved project schedule, construction plans, and erosion control
report.
3) Pre-disturbance vegetation shall be protected and retained wherever possible.
Removal or disturbance of existing vegetation shall be limited to the area required
for immediate construction operations, and for the shortest practical period of
time.
4) All soils exposed during land disturbing activity (stripping, grading, utility
installations, stockpiling, filling, etc.) shall be kept in a roughened condition by
ripping or disking along land contours until mulch, vegetation, or other permanent
erosion control is installed. No soils in areas outside project street rights of way
shall remain exposed by land disturbing activity for more than thirty (30) days
before required temporary or permanent erosion control (e.g. seed/mulch,
landscaping, etc.) is installed, unless otherwise approved by the Stormwater
Department.
5) The property must be watered and maintained at all times during construction
activities so as to prevent wind-caused erosion. All land disturbing activities shall
be immediately discontinued when fugitive dust impacts adjacent properties, as
determined by the City Engineering Department.
6) All temporary (structural) erosion control measures must be inspected and
repaired or reconstructed as necessary after each runoff event and every 14 days in
order to assure continued performance of their intended function. All retained
sediments, particularly those on paved roadway surfaces, shall be removed and
disposed of in a manner and location so as not to cause their release into any
13
drainage way.
7) No stockpile shall exceed ten (10) feet in height. All soil stockpiles shall be
protected from sediment transport by surface roughening, watering, and perimeter
silt fencing. Any soil stockpile remaining after 30 days shall be seeded and
mulched.
8) City Ordinance prohibits the tracking, dropping, or depositing of soils or any other
material onto city streets by or from any vehicle. Any inadvertent deposited
material shall be cleaned immediately by the contractor.
14
5.2. City of Fort Collins Erosion Control Security Calculations
The cost of erosion control for the site was compared to the cost to reseed the entire site
and the greater cost was used to establish the erosion control escrow amount. The cost to
reseed the site is estimated at $4,895.00. Using a multiplier of 1.5 the erosion control
escrow amount would be $7,342.50. The site erosion control cost is estimated at
$6,123.00. Using a multiplier of 1.5 the erosion control escrow amount would be
$9,184.50. The larger sum of the Erosion Control cost and the Reseeding cost shall be
used for the escrow account. Therefore, the Erosion Control Escrow amount is $9,184.50
See Table 6.1 for a break-down of the costs associated with seeding and erosion control.
Table 6.1: Erosion Control Cost Estimate
15
6. SWMP IMPLIMENTATION
It is the responsibility of the contractor to operate and maintain all facilities and systems
of treatment and control which are installed to achieve compliance with the conditions of
the permit. This includes effective performance, adequate funding, adequate staffing and
training, etc. (see permit).
All personnel on the construction site who will be in a position to affect or be affected by
the SWMP shall be trained prior to beginning work. These individuals will be given
general orientation information regarding the project and SWMP, shown where the
SWMP is physically located, the SWMP will be explained to them and available for their
review, and the enforcement policy will be reviewed. After this training, a certification
that the employee or subcontractor’s employee is familiar with the document and its
procedures will be signed. Copies of these certifications shall be included in the SWMP
notebook Appendix. Throughout the construction, as a part of a weekly safety meeting,
the SWMP will be reviewed with all attendees and any incidents discussed. All attendees
shall be logged.
APPENDIX A—BMP DETAILS
Q
APPENDIX B—EROSION CONTROL PLAN AND SITE MAP
RAIN
GARDEN A
RAIN GARDEN B
RAIN GARDEN B
0
30'
30 15 30 60
SCALE: 1" =
PREPARED FOR
PROJ. NO.
DATE:
SCALE (H):
SCALE (V):
CHECKED BY:
DESIGNED BY:
PROJECT NAME
HARMONY COTTAGES
EROSION CONTROL PLAN
05/18/16
1"=30'
N/A
SB
RA
1255-028-00
13 of 20
HABITAT FOR HUMANITY
4001 S. TAFT HILL ROAD
FORT COLLINS, CO 80525
PHONE: 970.223.4522
PRELIMINARY
NOT FOR CONSTRUCTION
LEGEND
PROPOSED DIRECTION OF OVERLAND FLOW
VEHICLE TRACKING CONTROL
SILT FENCE
INLET PROTECTION (TYPE I)
EROSION LOG DITCH INSTALLATION
CONCRETE WASHOUT
(CONSTRUCTION ENTRANCE)
GRAVEL BAG
NOTES:
1. CONTRACTOR TO PROVIDE AND MAINTAIN ALL NECESSARY EROSION
CONTROL MEASURES PRIOR TO AND THROUGHOUT CONSTRUCTION.
PLACE EROSION CONTROL PROTECTION AT ALL EXISTING INLETS
DOWNSTREAM FROM THE CONSTRUCTION AREA. EROSION CONTROL
PROTECTION SHALL REMAIN IN PLACE UNTIL CONSTRUCTION IS
COMPLETE AND ALL DISTURBED GROUND IS ADEQUATELY VEGETATED
WITH OWNER'S APPROVAL FOR REMOVAL.
2. THE EXTENT OF EROSION CONTROL PROTECTION SHALL BE
OBSERVED AND ADJUSTED AS NEEDED DURING CONSTRUCTION
BASED ON SITE CONDITIONS AND THE PERFORMANCE OF THE
EROSION CONTROL CONTROL MEASURES SHOWN, TO SUPPLY
SUFFICIENT EROSION CONTROL AND MINIMIZE DOWNSTREAM
WATERWAY POLLUTION.
3. RAIN GARDEN OUTLET STRUCTURES TO BE COVERED WITH A
GEOTEXTILE FABRIC TO ELIMINATE SEDIMENT FROM ENTERING THE
BASIN AND THE UNDERGROUND STORM SYSTEM.
EROSION LOG
EROSION LOG FILTER AT DROP INLET
R
APPENDIX C—CONSTRUCTION SEQUENCE
Location: Harmony Cottages
Date: April 2016
(Construction Phases) Mobilization
Clear, Strip,
Grade
Utility
Installation Subgrade
Curb, Gutter and
Sidewalk Paving
Building
Construction Landscape Demobilization
Best Management Practices (BMPs)
Structural "Installation"
Silt Fence Barriers*
Inlet Protection on Harmony*
Contour Furrows (Ripping / Disking)
Sediment Trap / Filter
Vehicle Tracking Pad*
Concrete Washout*
Flow Barriers (Wattles)*
Stream Flow Diversion*
Rip Rap
*All BMPs to be Removed once Construction
is Complete.
Vegetative
Temporary Seeding Planting Any time the site will sit dorment longer than 30 Days.
Mulching/Sealant Any time the site will sit dorment longer than 30 Days.
Permanent Seeding Planting
Other:
Construction Sequence Chart
Construction Sequence Chart
S
APPENDIX D—SOIL INFORMATION
Hydrologic Soil Group—Larimer County Area, Colorado
(Harmony Cottages)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/18/2016
Page 1 of 4
4486520 4486550 4486580 4486610 4486640 4486670 4486700
4486520 4486550 4486580 4486610 4486640 4486670 4486700
490240 490270 490300 490330 490360 490390 490420 490450 490480 490510 490540
490240 490270 490300 490330 490360 490390 490420 490450 490480 490510 490540
40° 31' 52'' N
105° 6' 55'' W
40° 31' 52'' N
105° 6' 41'' W
40° 31' 45'' N
105° 6' 55'' W
40° 31' 45'' N
105° 6' 41'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 50 100 200 300
Feet
0 20 40 80 120
Meters
Map Scale: 1:1,470 if printed on A landscape (11" x 8.5") sheet.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
3 Altvan-Satanta loams, 0
to 3 percent slopes
B 4.6 88.5%
35 Fort Collins loam, 0 to 3
percent slopes
C 0.6 11.5%
Totals for Area of Interest 5.2 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three 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 thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
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 consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at 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 is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Hydrologic Soil Group—Larimer County Area, Colorado Harmony Cottages
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/18/2016
Page 3 of 4
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Larimer County Area, Colorado Harmony Cottages
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/18/2016
Page 4 of 4
K Factor, Whole Soil—Larimer County Area, Colorado
(Harmony Cottages)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/18/2016
Page 1 of 3
4486520 4486550 4486580 4486610 4486640 4486670 4486700
4486520 4486550 4486580 4486610 4486640 4486670 4486700
490240 490270 490300 490330 490360 490390 490420 490450 490480 490510 490540
490240 490270 490300 490330 490360 490390 490420 490450 490480 490510 490540
40° 31' 52'' N
105° 6' 55'' W
40° 31' 52'' N
105° 6' 41'' W
40° 31' 45'' N
105° 6' 55'' W
40° 31' 45'' N
105° 6' 41'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 50 100 200 300
Feet
0 20 40 80 120
Meters
Map Scale: 1:1,470 if printed on A landscape (11" x 8.5") sheet.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Soil Rating Lines
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Soil Rating Points
.02
.05
.10
.15
.17
.20
.24
.28
.32
.37
.43
.49
.55
.64
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
K Factor, Whole Soil
K Factor, Whole Soil— Summary by Map Unit — Larimer County Area, Colorado (CO644)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
3 Altvan-Satanta loams, 0
to 3 percent slopes
.28 4.6 88.5%
35 Fort Collins loam, 0 to 3
percent slopes
.43 0.6 11.5%
Totals for Area of Interest 5.2 100.0%
Description
Erosion factor K indicates the susceptibility of a soil to sheet and rill erosion by
water. Factor K is one of six factors used in the Universal Soil Loss Equation (USLE)
and the Revised Universal Soil Loss Equation (RUSLE) to predict the average
annual rate of soil loss by sheet and rill erosion in tons per acre per year. The
estimates are based primarily on percentage of silt, sand, and organic matter and
on soil structure and saturated hydraulic conductivity (Ksat). Values of K range from
0.02 to 0.69. Other factors being equal, the higher the value, the more susceptible
the soil is to sheet and rill erosion by water.
"Erosion factor Kw (whole soil)" indicates the erodibility of the whole soil. The
estimates are modified by the presence of rock fragments.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Layer Options (Horizon Aggregation Method): Surface Layer (Not applicable)
K Factor, Whole Soil—Larimer County Area, Colorado Harmony Cottages
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/18/2016
Page 3 of 3
Wind Erodibility Group—Larimer County Area, Colorado
(Harmony Cottages)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/18/2016
Page 1 of 3
4486520 4486550 4486580 4486610 4486640 4486670 4486700
4486520 4486550 4486580 4486610 4486640 4486670 4486700
490240 490270 490300 490330 490360 490390 490420 490450 490480 490510 490540
490240 490270 490300 490330 490360 490390 490420 490450 490480 490510 490540
40° 31' 52'' N
105° 6' 55'' W
40° 31' 52'' N
105° 6' 41'' W
40° 31' 45'' N
105° 6' 55'' W
40° 31' 45'' N
105° 6' 41'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 50 100 200 300
Feet
0 20 40 80 120
Meters
Map Scale: 1:1,470 if printed on A landscape (11" x 8.5") sheet.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
1
2
3
4
4L
5
6
7
8
Not rated or not available
Soil Rating Lines
1
2
3
4
4L
5
6
7
8
Not rated or not available
Soil Rating Points
1
2
3
4
4L
5
6
7
8
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
Wind Erodibility Group
Wind Erodibility Group— Summary by Map Unit — Larimer County Area, Colorado (CO644)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
3 Altvan-Satanta loams, 0
to 3 percent slopes
5 4.6 88.5%
35 Fort Collins loam, 0 to 3
percent slopes
5 0.6 11.5%
Totals for Area of Interest 5.2 100.0%
Description
A wind erodibility group (WEG) consists of soils that have similar properties
affecting their susceptibility to wind erosion in cultivated areas. The soils assigned
to group 1 are the most susceptible to wind erosion, and those assigned to group
8 are the least susceptible.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Lower
Wind Erodibility Group—Larimer County Area, Colorado Harmony Cottages
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/18/2016
Page 3 of 3
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 10, Sep 22, 2015
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Apr 22, 2011—Apr 28,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Wind Erodibility Group—Larimer County Area, Colorado
(Harmony Cottages)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/18/2016
Page 2 of 3
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 10, Sep 22, 2015
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Apr 22, 2011—Apr
28, 2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
K Factor, Whole Soil—Larimer County Area, Colorado
(Harmony Cottages)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/18/2016
Page 2 of 3
Survey Area Data: Version 10, Sep 22, 2015
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Apr 22, 2011—Apr 28,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Hydrologic Soil Group—Larimer County Area, Colorado
(Harmony Cottages)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
2/18/2016
Page 2 of 4