HomeMy WebLinkAboutNIX FARM NATURAL RESOURCES FACILITY - FDP - FDP130023 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT (3)EROSION CONTROL REPORT/STORMWATER MANAGEMENT PLAN
FOR
Nix Farm Natural Areas Facility
Major Amendment
Prepared by:
Interwest Consulting Group
1218 West Ash, Suite C
Windsor, Colorado 80550
Phone: 970.674.3300
Fax: 970.674.3303
Prepared for:
City of Fort Collins
Operation Services
300 LaPorte Ave., Building B
Fort Collins, CO 80521
(970) 221-6273
May 15, 2013
TABLE OF CONTENTS
1. INTRODUCTION .................................................................................................................... 1
2. SITE DESCRIPTION ............................................................................................................... 1
3. BMPS FOR STORMWATER POLLUTION PREVENTION ................................................ 4
3.1. Erosion and Sediment Controls ........................................................................................ 4
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
7. SWMP IMPLIMENTATION ................................................................................................. 12
APPENDIX A— BMP DETAILS ........................................................................................... AM
APPENDIX B— EROSION/SEDIMENTATION CONTROL PLAN AND SITE MAP ... BN
APPENDIX C— CONSTRUCTION PHASING SCHEDULE ............................................. CO
APPENDIX D— CONTRACTOR FORMS / CERTIFICATIONS ...................................... DP
LIST OF FIGURES
Figure 1--Vicinity Map ................................................................................................................... 2
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 less than
one acre and the permit is not required.
2. SITE DESCRIPTION
The site is located north of the Burlington Northern Railroad Tracks, west of Timberline
Rd, south of the Cache La Poudre River, and east of Lemay Avenue. The site contains
approximately 27.48 acres; however, the proposed new office development will disturb
approximately 0.7 acres. The site is zoned POL, Public Open Lands.
The project will construct a two-story, 4000 sf office building located just west of the
existing maintenance building. Sidewalks and additional parking will also be
constructed. The existing lot is already developed and equipped with an existing water
quality pond in place.
The site is located north of the Burlington Northern Railroad Tracks, west of Timberline
Rd, south of the Cache La Poudre River, and east of Lemay Avenue. The project is
located in a portion of Section 18, Township 7 North, Range 68 West of the Sixth
Principal Meridian, in the City of Fort Collins, Larimer County, Colorado. A vicinity
map is provided on the following page.
Figure 1--Vicinity Map
The existing lot is already developed and equipped with an existing water quality pond in
place. The majority of the proposed development will be collected and conveyed to the
proposed water quality pond on the southernmost portion of the site where it will be
allowed to settle before being released into the adjoining drainage easement to the
southeast of the property.
With the building addition, the majority of water will sheet to culverts and swales to the
existing storm system. All paved areas are designed with a minimum slope of 0.5% and
all grassed areas are designed with a minimum slope of 2.0%. Side slopes in grassed areas
are graded to a maximum of 4:1.
The anticipated sequence of construction shall progress as follows:
1) Site demolition and as quickly as possible the installation of perimeter erosion
control measures (other measures as required for erosion control will be
constructed throughout) existing culvert protection, wattles along the existing
swale to the north of the proposed building and the concrete washout and vehicle
tracking pad off of Hoffman Mill Road.
2) Clearing, stripping and grading
3) Utility installation
4) Sub-grade preparation for the drives and sidewalks
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.
The 10-year runoff coefficient associated with this project will be 0.55.
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. The ultimate receiving water for this area is
the Canal Importation Floodway.
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 pad, concrete washout area and wattles 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.
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.
Wattles prevent sediment from entering storm drainage systems prior to permanent
stabilization of the disturbed site area via ponding and settling of sediment. Wattles 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.
Wattles shall also be implemented as sediment control in existing and proposed swales as
necessary. Wattles 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.
3.2 Materials Handling and Spill Prevention
INFORMATION TO BE PROVIDED BY THE CONTRACTOR PRIOR TO
COMMENCEMENT OF CONSTRUCTION AND UPDATED AS NECESSARY
THROUGHOUT THE CONSTRUCTION SEQUENCE. ADD PAGES TO THE PLAN
AS NECESSARY. THIS WILL INCLUDE IDENTIFYING POTENTIAL POLUTION
SOURCES FROM THE PERMIT AS WELL AS THE BMPS AND DETAILS.
Measures that will be implemented to avoid or contain stormwater pollution from the
above procedures and sources are as follows:
INFORMATION TO BE PROVIDED BY THE CONTRACTOR PRIOR TO
COMMENCEMENT OF CONSTRUCTION AND UPDATED AS NECESSARY
THROUGHOUT THE CONSTRUCTION SEQUENCE.
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 foundation construction, paving and
repaving, slope construction, and demolition required as shown on the
plans. BMPs will include wattles on existing and proposed culverts,
minimizing disturbance of existing vegetation and hard surfaces, and slope
roughening and tracking of slopes after disturbance and prior to
landscaping, paving, or building will be implemented.
2) Vehicle tracking of sediment – YES – The construction will require that
subgrade be prepared for pavement and that vehicles drive on unpaved
surfaces to the proposed building and utility improvement locations.
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.
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
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 – NO – Vehicle
maintenance and fueling will not take place. No fuel will be stored on site.
7) Significant dust or particulate generating processes – NO – The area of
heavy construction is very limited and none of the operations are expected
to generate significant dust.
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, 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 – YES – A concrete washout will be
provided on site. This will be used for trucks and for any masonry /
concrete tools. The concrete washout will be located adjacent to Hoffman
Mill Road next to the entrance drive aisle.
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.
13) Other areas where potential spills can occur – NO – The above 12 items
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
Long-term erosion control for this site will be the established vegetative cover,
landscaping and xeriscaping along with the completed site improvements (pavement and
buildings). Final stabilization shall be considered achieved once all proposed site
improvements are in place 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).
Areas controlled by grass sod will be considered established upon the completion of the
sod installation.
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 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).
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 are included in the 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
APPENDIX B—EROSION CONTROL PLAN AND SITE MAP
APPENDIX C—CONSTRUCTION PHASING SCHEDULE
APPENDIX D—CONTRACTOR FORMS/CERTIFICATIONS