HomeMy WebLinkAboutWOODWARD BLUE HOME PROJECT (FORMERLY LINK-N-GREENS) - FDP - FDP130026 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT (5)EROSION CONTROL REPORT/STORMWATER MANAGEMENT PLAN
FOR
Woodward Blue Home Project
Over-Over -lot Grading PPPPllllaaaannnn
Prepared by:
Interwest Consulting Group
1218 West Ash, Suite C
Windsor, Colorado 80550
Phone: 970.674.3300
Fax: 970.674.3303
Prepared for:
Woodward, Inc.
1000 East Drake Road
Fort Collins, CO 80525
(970) 482-5811
June 13, 2013
June 13, 2013
Mr. Wes Lamarque
City of Fort Collins Stormwater
700 Wood Street
Fort Collins, CO 80522-0580
RE: Erosion Control Report for Woodward Blue Home Project Over-lot Grading Plan
Dear Wes,
I am pleased to submit for your review and approval, this Erosion Control Report / Stormwater
Management Plan for the Woodward Blue Home Project Over-lot Grading Plan. 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,
Skylar Brower, P.E.
Colorado Professional
Engineer No. 44248
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 ......................................................................... 6
4. STORMWATER MANAGEMENT CONTROLS .................................................................. 8
4.1. SWMP Administrator ....................................................................................................... 8
4.2. Identification of Potential Pollution Sources ................................................................... 8
5. FINAL STABILIZATION AND LONG TERM STORMWATER MANAGEMENT ......... 10
6. INSPECTION AND MAINTENANCE ................................................................................. 11
6.1. City of Fort Collins Standard Erosion and Sediment Control Notes ............................. 11
6.2. City of Fort Collins Erosion Control Security Calculations ........................................... 12
7. SWMP IMPLIMENTATION ................................................................................................. 13
APPENDIX A—BMP DETAILS ................................................................................................ A
APPENDIX B—EROSION CONTROL PLAN ......................................................................... B
LIST OF FIGURES
Figure 1--Vicinity Map ................................................................................................................... 2
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 purpose of this
report is to satisfy the requirements outlined by The City of Fort Collins Erosion Control
Report Requirements. The contractor will be responsible for obtaining the State of
Colorado General Permit prior to construction.
2. SITE DESCRIPTION
The Woodward Blue Home Project is located in the Southwest Quarter of Section 7, T-7-
N, R-68-W and in the Southeast Quarter of Section 12, T-7-N, R69-W of the 6th PM,
City of Fort Collins, Larimer County, Colorado. A vicinity map is provided on the
following page.
The site is located north of Mulberry Road, west of Lemay Avenue, south of Lincoln
Avenue, and east of the Cache la Poudre River. The proposed site is approximately 101.6
acres, was previously used as a public golf course (Link-N-Greens) and is covered by
irrigated grasses, mature trees and natural vegetation along the river bank. The land
generally slopes north to south at an average slope of 0.5%. An irrigation ditch, Coy
Ditch, previously fed the existing ponds which were used for irrigation of the golf course.
However, these water rights were not conveyed with the purchase of the property and Coy
Ditch located on the Woodward property will be removed or abandoned in place.
Proposed Site Improvements
The proposed over-lot grading will disturb approximately 95.1 acres of the 101.6 acre
site. The over-lot grading phase of the project will consist of moving or importing
2
approximately 400,000 cubic yards of dirt on the site. The majority of the truck traffic to
and from the site will be located off of S. Lemay Avenue. The anticipated truck route
will be west along E. Lincoln Avenue from Timberline Road, south on Lemay Avenue
and then right into the site. Exiting trucks will turn right onto southbound Lemay and
then back to Mulberry. The construction entrance off of Lincoln Avenue will be limited
to minor traffic to prevent traffic inconveniences to neighboring businesses and residents.
There are no buildings, drives, walks, or utility improvements associated with this work.
The existing irrigation ditch, Coy Ditch, will be removed and all of the existing irrigation
ponds on site will be filled in with this work with the exception of one large pond that sits
just north of the existing Poudre River Trail. This pond will be reshaped and used to
address water quality for future improvements and become a part of the overall river
restoration project being undertaken by the City of Fort Collins Natural Areas
Department. The pond is feed by groundwater and there is no direct outlet proposed with
the over-lot grading from the pond to the Poudre River.
Construction staging of materials and overnight fleet vehicles shall be located beyond
(north) the limits of the Effective 100-year Floodplain. Stockpiles of materials shall be
located beyond (north) the limits of the Effective 100-year Floodway. A Floodplain User
Permit is required for this work prior to construction.
See the Over-lot Grading Plans for additional Floodplain, Grading and Erosion Control
related notes.
3
Figure 1--Vicinity Map
4
The existing Poudre River Trail that runs adjacent to the river and along the southern
boundary of the site will remain in place during the over-lot grading phase and no grading
is proposed south/west of the trail as part of this initial grading operation. A future
project will include the removal and reconstruction of the trail, river bank grading,
stabilization work, topsoil spreading, and vegetation/planting plans. Much of the
proposed grading is 2’ – 3’ below the existing grade of the trail. The trail will serve as a
natural cut off berm between the proposed site grading and the Cache la Poudre River.
All areas where proposed grades will be above the grade of the existing trail will be
protected with silt fence.
There are also multiple areas throughout the site that will serve as temporary sediment
basins. These areas correspond with future drainage facility (rain gardens) areas to
address water quality. The grading contours shown on the plans reflect the future
finished grade contours as shown on the approved Preliminary Development Plan (PDP)
documents. The contractor shall adjust these grades accordingly to account for building
pads, pavement sections and future topsoil spreading.
The anticipated sequence of construction shall progress as follows:
1) Installation of perimeter erosion control measures (other measures as required for
erosion control will be constructed throughout), tree protection fencing for trees to
remain, a vehicle tracking pad off of the Lincoln Ave access and another vehicle
tracking pad off of the Lemay Ave access.
2) Site demolition, clearing, stripping and tree removal
3) Over-lot grading
4) Grading of temporary sediment basins / future drainage facilities
5) Over excavation and sub-grade preparation for the proposed building pads
(buildings are part of a future phase under a separate plan approval process)
6) Final site stabilization (seeding and mulching)
As previously mentioned, the proposed improvements consist of over-lot grading only.
There will be no new impervious area associated with this phase of the project. Therefore
the 10-year runoff coefficient associated with this project will be 0.05. Future
development plans for the Woodward Blue Home Project will identify storm drainage
5
patterns, water quality systems and outfall locations to the Poudre River.
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. There are no anticipated non-stormwater components of discharge
with this project. The ultimate receiving water for this area is the Cache la Poudre River.
3. BMPS FOR STORMWATER POLLUTION PREVENTION
3.1. Erosion and Sediment Controls
Structural Practices: Structural practices for the site will consist mainly of vehicle
tracking pads, wattles/culvert inlet protection and silt fence 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 State Permit.
The vehicle tracking pads are 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.
Silt fence will prevent sediment from leaving the site or entering the water quality pond
prior to permanent stabilization of the disturbed site area via ponding and settling of
sediment. Silt fence shall be placed around the perimeter of the water quality pond and
along the site boundary where the proposed grades would enable runoff to exit the site.
Silt fence shall be installed prior to over-lot grading where applicable and immediately
upon completion of over-lot grading.
6
Erosion logs prevent sediment from entering storm drainage systems prior to permanent
stabilization of the disturbed site area via ponding and settling of sediment. Erosion logs
shall be placed at the upstream end and downstream end of new culverts and existing
culverts near the site. Storm sewer culvert protection must be inspected and maintained
after every rainfall event that produces runoff. Sediment must be removed and rocks
replaced. Erosion Logs shall also be implemented as sediment control in existing and
proposed swales as necessary. Erosion logs shall be installed on existing swales and
culverts prior to commencing over-lot grading.
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.
As previously mentioned, the existing Poudre River Trail will be protected in place
during this phase of the over-lot grading. The existing trail grade is higher than the
majority of the proposed grades just north of the trail so it will serve as a natural berm to
eliminate site runoff from entering the Cache la Poudre River.
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.
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
near the center of the site. Fueling will be accomplished with fueling trucks on an as
7
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.
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.
8
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.
4. STORMWATER MANAGEMENT CONTROLS
4.1. SWMP Administrator
The Local Contact and SWMP Administrator is Sal Moya, Sr. Project Manager for
Mortenson Construction, phone: (720) 920-4370.
Sal Moya will be responsible for developing, implementing, maintaining, and revising the
SWMP. Sal will also be responsible for required inspections and coordinating and
documenting changes or repairs resulting from inspections. As the SWMP
Administrator, Sal 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
9
for this project:
1) Disturbed and stored soil – YES – The construction will require that areas
be disturbed exposing soil including slope construction, over-excavation
for future buildings, and demolition required as shown on the plans.
BMPs will include erosion logs on the existing culvert and concrete
channel in the southeast corner of the site (flow coming from existing curb
cut in Lemay Ave), silt fence along the perimeter of the site where there is
potential for runoff and sediment to leave the site, and slope roughening
and tracking of slopes after disturbance and prior to final stabilization.
2) Vehicle tracking of sediment – YES – The construction will require
approximately 400,000 cubic yards of dirt to be moved on site to complete
the over-lot grading phase of the project. 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 one of two vehicle
tracking pads prior to leaving the site.
3) Management of contaminated soil – NO – Soil borings do not indicate any
existing contamination.
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 – Construction equipment will be stored
in the designated storage area as indicated on the plans. 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 at the construction staging area
near the center of the site (this area is delineated on the plan). No fuel will
be stored on site.
7) Significant dust or particulate generating processes – YES –
Approximately 95 acres of the total 101.5 acre site will undergo over-lot
grading with significant earthwork operations. In order to control the dust
or particulate generating process a water truck will be on site at all times.
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”
10
and the liquid disposed of properly and legally.
9) On-site waste management – YES – The building and site construction
(access drive, concrete walks, underground utilities) 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. 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 – NO – There will be no concrete work
associated with the over-lot grading.
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 – A trash dumpster will be available for worker’s trash and will be
located near the existing club house which serves as the construction
trailer. Portable toilets will be on site near the construction trailer as well.
Portable toilets will also be placed near the construction staging area and
the historic area on a temporary and as needed basis.
13) Other areas where potential spills can occur – NO – The above 12 items
are adequate for the anticipated construction process.
5. FINAL STABILIZATION AND LONG TERM STORMWATER
MANAGEMENT
Long-term erosion control for this site will be the established vegetative cover.
A dry land seed mix (see below) is proposed for the entire site and no irrigation, fertilizer,
or other soil amendment is proposed.
Native Seed Mix, Low Grow Native or Approved Equivalent
10% Big Bluegrass (Sherman)
10% Sandberg / Canby Bluegrass
40% Arizona Fescue (Redondo)
40% Sheep Fescue (Ovina)
In addition to standard mix above, add additional 15% Canada Rye and additional 15%
Western Wheatgrass
Final stabilization shall be considered achieved once the over-lot grading is complete and
all vegetation is established. Vegetation shall not be considered established until a
ground cover is achieved which is demonstrated to be mature enough to control soil
erosion (typically 70% of the original vegetative cover).
11
6. 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/her 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
finished and a certification that it was done properly).
6.1. 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
12
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
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.
6.2. City of Fort Collins Erosion Control Security Calculations
The erosion control escrow amount is $15,551
Item Quantity Unit
Unit
Price Total Cost
Construction Entrance 2 EA $1,800 $3,600
Erosion Log 3 EA $155 $465
Silt Fence 5,743 LF $2 $11,486
Total $15,551
13
7. 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 will be included in the SWMP
notebook. 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
Surface Roughening (SR) EC-1
November 2010 Urban Drainage and Flood Control District SR-3
Urban Storm Drainage Criteria Manual Volume 3
B
APPENDIX B—EROSION CONTROL PLAN