HomeMy WebLinkAboutBUCKINGHAM PLACE, SECOND FILING - PDP/FDP - FDP150001 - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORT (3)Appendix A
Calculation of Peak Runoff
Appendix C
Erosion Control Report
Buckingham Place, Second Filing
Fort Collins, Colorado
A. Site Description
1. Construction Activity Description
Construction activity includes installation of BMP’s, grading, utility (sanitary sewer and
waterline) construction, removal and replacement of asphalt and concrete in 3rd Street,
and on-site home building construction activities.
2. Proposed Sequence for Major Activities
The project is expected to be constructed in two phases. Phase one consists of the
installation of an 8” wastewater main in 3rd Street. Phase one also includes the
installation of two wastewater service and water service connections to the two
proposed lots. These will be stubbed into the proposed lots three feet past the front
property line. The sequence of construction is expected to consist of the following:
• Installation of inlet protect for existing inlet on 3rd street located along the
west side of the street to the south of the project site.
• Pavement cuts and removal of asphalt paving within 3rd Street for installation
of utilities.
• Installation of utilities.
• Asphalt patching in 3rd Street.
• Construction is anticipated to begin in September, 2015, and is expected to
take two weeks.
Phase two is expected to consist of construction of single-family homes within the two
proposed lots. These homes are expected to be constructed by others after phase one
is completed.
The anticipated sequence for major construction activities is follows:
• Installation of erosion control as per City of Fort Collins standard detail D-
52.
• Installation of on-site water and wastewater services.
• Earthwork, including cut/fill on site.
• Construction of building foundations.
• Construction of buildings.
• Final site grading and landscaping.
• Construction is anticipated to begin after Phase One completion.
It should be noted that the curb/gutter, paving improvements, detached sidewalk and
driveway aprons will be constructed as part of a City capital project. Erosion control
for that construction will be provided by the city project.
3. Area Estimates
Phase One construction is expected to disturb approximately 2600 square feet. This
area is located within the existing right-of-way for 3rd Street.
Phase Two construction is expected to disturb 12,529 square feet. This are is located
within the two proposed residential lots
4. Soil Description
Earth Engineering Consultants completed the soils investigations for the project site and
presented the results in the Soil Description and Limitation Report, 3rd Street Pavement
Section Design, Buckingham Place, Second Filing, Fort Collins, Colorado. According to this
report, the surficial soils are mainly clay loam identified specifically as Loveland clay loam
and Table Mountain loam. These soils exhibit low strength and shrink/swell potential
and are unstable surficial soils.
5. Existing Vegetation
The existing site is undeveloped with approximately 60% vegetative cover. The
vegetative cover consists of native grasses and shrubs. There is a large amount of bare
dirt on the property that appears to be driven on regularly.
6. Location and Description of Other Potential Pollution
Sources
Potential pollutant sources include sediment, uncovered soil, construction machinery,
building materials, and fertilizers. It is anticipated that any storage of materials or
machinery will be on site and surrounded by silt fence or straw wattles.
7. Non-Stormwater Components of Discharge
According to the Preliminary Geotechnical Evaluation, 3rd Street and Buckingham, Fort Collins,
Colorado by Earth Engineering Consultants:
Free water was observed at depths on the order of 11 to 14 feet below present site
grades at the time of drilling. Those depths are on the order of 4 feet or less below the
apparent surface of the native soils
At these depths, it is expected that groundwater may be encountered during the
construction of utilities within Phase One. If groundwater is encountered, the
contactor shall obtain state and local dewatering permits as needed.
The other non-storm water components of discharge include water line flushing,
irrigation to establish seeding, and watering for dust mitigation and compaction.
Concrete truck washout will not be allowed within the project site.
8. Receiving Waters
This site is located in the Dry Creek Drainage Basin of Fort Collins, Colorado. Runoff
from the construction within 3rd Street drains towards an existing inlet on the west side
of 3rd Street, south of the project site. The proposed lots will drain to 3rd street and/or
adjacent property to the south.
B. Stormwater Management Controls
1. SWMP Administrator
The SWMP Administrator is currently:
Mr. Charles Meserlian
700 N. College Avenue
Fort Collins, CO 80524
Phone: 970-490-1251
Fax: 970-484-6695
2. Identification of Potential Pollutant Sources
This section focuses on the identification of the potential pollutant sources and briefly
discusses the Best Management Practices (BMPs) that will be used. More information
on the BMP’s utilized on this site is included in the next section “3. Best Management
Practices”.
A. All disturbed and stored soils;
It is expected that there will be stockpiles of dirt on the site from the utility
installations and the foundation excavation. Silt fencing, as per Fort Collins standard
detail D-52, is proposed to control sediment.
B. Vehicle tracking of sediments
The construction is so limited on this site that a vehicle tracking control pad has not
been shown on the erosion control plan. At the end of each workday, the
Contractor shall sweep or scrape 3rd Street to dispose of debris that may have
accumulated during the workday.
C. Management of contaminated soils
There are no known contaminated soils on the site. However, if the contractor
encounters contaminated soils during the construction process they should stop
construction immediately and notify the appropriate government authorities in
accordance with good construction safety and practice.
D. Loading and Unloading operations
Loading and unloading will take place on the site. Silt fencing shall be installed to
control sediment from site onto the street.
E. Outdoor storage activities (building materials, fertilizers, chemicals, etc.)
Storage of construction materials (prior to installation) may include water and
sanitary sewer piping, home building materials, soil and/or fertilizers. All materials
stored longer than one week will be placed on pallets and covered to prevent direct
contact with the ground and potential surface runoff.
F. Vehicle and equipment maintenance
Vehicle and equipment maintenance are not expected to be needed, and will not be
allowed on site or on 3rd Street. Should emergency maintenance be required, it shall
be performed on the hard surface or gravel areas at least 50’ from any stormwater
feature (ie inlet, storm sewer, concentrated runoff, swale, etc.)
G. Significant dust or particulate generating processes
The Contractor shall comply with applicable air pollution control requirements of
the City. The Contractor shall take appropriate actions to minimize atmospheric
pollution and take reasonable precautions which shall include, but not be limited to:
1. The use of water for control of dusts for construction processes such as
demolition, grading, or the clearing of land.
2. Covering, at all times when in motion, open-bodied trucks transporting
materials likely to give rise to airborne dusts.
H. Routine maintenance activities involving fertilizers, pesticides,
detergents, fuels, solvents, oils, etc;
Chemicals, fuels, lubricants, and paints typical with building construction stored on-
site will be in water tight containers and covered as necessary and stored in a
bermed area, a storage building, or within a vehicle to act as secondary containment.
I. On-site waste management practices (waste piles, liquid wastes,
dumpsters, etc.);
Waste piles should be covered or surrounded by silt fence or straw wattles. Liquid
wastes should be collected and stored in covered containers and disposed of
properly.
Solid waste materials, including disposable materials incidental to the major
construction activities, will be collected in on-site dumpsters. The containers will
be emptied periodically and trucked away from the site. Dumpsters shall have
covers.
J. Concrete truck / equipment washing, including the concrete truck chute
and associated fixtures and equipment;
A dedicated concrete washout area is not anticipated to be necessary for this
project. The contractor shall clean out equipment away so that runoff is not
allowed to leave site and enter 3rd Street, the Coy Ditch, or neighboring properties.
K. Dedicated asphalt and concrete batch plants;
There will not be dedicated asphalt or concrete batch plants on this site.
L. Non-industrial waste sources such as worker trash and portable toilets
Worker’s trash shall be disposed of in an onsite dumpster. The site should be free
of trash at the end of each working day.
A portable toilet shall be utilized by construction personnel and serviced regularly
by a commercial operator. They shall be located a minimum of 5 feet from the curb
or 50 feet from inlets and must be anchored. Sanitary facilities shall not be located
on hard surfaces that may promote tipping.
M. Other areas or procedures where potential spills can occur.
BMP’s such as tarps and drip pans should be used for painting, stucco, dry-wall etc.
operations
C. Best Management Practices (BMP’s)
Once construction activity begins, Best Management Practices (BMP’s) intended to
contain sediment onsite must be constructed, inspected and repaired as necessary. Such
controls must be functional before upslope land disturbance takes place. The BMP’s will
be installed as shown on the Grading and Erosion Control plan shown in Appendix D.
They must be supplemented as on-site experience proves necessary in order to control
sediment, pollutant discharge, and insure public safety.
The following temporary and permanent BMP’s will be installed and maintained to
control on-site erosion and prevent sediment from traveling off-site during construction.
The descriptions below provide some information about each BMP, but further
information can be found in Urban Storm Drainage Criteria Manual, Volume 3 – Best
Management Practices by Urban Drainage and Flood Control District.
Temporary BMP’s
• Construction Fence is a temporary BMP. The contractor is to place
construction fencing around development as needed to limit access by
construction equipment and personal vehicles to designated areas of ingress and
egress. Since the majority of site will soon be surrounded by a permanent
fence, there will be limited construction fence needed on this project.
• Inlet Protection is a temporary BMP that helps prevent soil and debris from
the site from entering the storm drain inlets and usually consists of a sediment
filter around or upstream of the storm drain inlet. Inlet protection allows storm
water to flow into the drain but only after excess sediment has been filtered
out. Inlet protection will be used on existing and proposed storm inlets and will
be installed at such time as construction of the storm sewer system occurs.
Inlet protection for this site will consist of wattles, which are meshed netting
“tubes” filled with straw, excelsior, or coconut fiber placed around grated inlets
and curb inlets. Wattles require proper installation and maintenance to ensure
their performance. Sizing shall be per manufacturer’s recommendation.
• Regular Meetings is a temporary and non-structural BMP. Regular meetings
with on-site workers including builders, suppliers, landscape personnel, etc.
should be conducted so that they are kept up to date with site standard
operating procedures.
• Silt Fence is a woven synthetic permeable fabric that filters runoff. Silt fence is
a temporary barrier that is installed prior to earthmoving activities and is placed
downstream of areas where runoff from construction activities is expected to
occur, especially along the site perimeter to allow sediment to settle from
runoff before water leaves the construction site. Silt fences will be installed per
manufacturer’s recommendations. Silt fence encourages sheet flow and is not
intended to be used in areas of concentrated flow. If concentrated flow is
encountered during the placement of the fence, an alternative BMP shall be used
and the SWMP should be updated to reflect this change.
• Street Sweeping and Vacuuming removes sediment that has been tracked
onto roadways to reduce sediment transport into storm drain systems or a
surface waterway. This practice should be used on the adjacent paved road to
the construction site. Paved roads should be inspected on a daily basis and
more frequently as needed.
• Temporary Seeding is the establishment of a temporary vegetative cover on a
graded area that will be exposed for longer 30 days. Temporary seeding can be
used on areas requiring temporary protection that will eventually need
permanent vegetation at the completion of the construction or it can be used
for areas that will be re-disturbed after a period of inactivity.
• Wind Borne Sediment and Dust Control measures will be provided during
the construction process to control wind borne sediment. During grading
activities, water will be applied to the disturbed soils for the purpose of
maintaining cohesion with clay type soils and also to meet moisture
requirements for compaction of disturbed soils. Other measures of mitigation
for wind erosion may include the timely installation of seed and mulch following
the establishment of final grade, and the timely installation of pavement following
completion of utility trenching operations and curb construction. Open areas
should be kept in a roughened condition.
Permanent BMP’s
• Permanent Seeding and Planting is the establishment of a permanent
perennial vegetation such as trees, shrubs, vines, grasses/sod, or legumes on
exposed areas for final permanent stabilization in order to provide stabilization
of the soil by holding soil particles in place. It also reduces storm water runoff
velocity, maintains sheet flow, protects the soil surface from erosion, promotes
infiltration of runoff, and improves wildlife habitat.
• Preservation of Existing Vegetation should occur where no construction
activity is expected to occur. Preservation of natural vegetation is generally a
permanent BMP and is applicable to construction sites with pre-existing
vegetation. Only land needed for building activities and vehicle traffic needs to
be cleared.
D. Erosion Control Sequencing
Prior to Construction
Silt Fence and Inlet Protection – Before construction begins, silt fence and gravel inlet
protection will be installed. These erosion control devices shall be in place, functional,
and maintained during and following the construction operations.
During Construction
Street Sweeping and Cleaning – The adjacent street shall be swept and cleaned on an as-
needed basis to ensure sediment is not being tracked away from the construction site.
Wind Borne Sediment and Dust Control – Wind borne sediment and dust control
measures should be implemented during grading activities.
Permanent Seeding – Permanent seeding or landscaping shall be placed immediately in
areas that are final graded and where little future disturbance is expected. In
particular, permanent seeding should be included on the side slopes of the detention
pond.
Temporary Seeding – The majority of the landscaped areas will be permanently
seeded/planted. However, if any of the areas are left disturbed without permanent
stabilization 30 days after grading, temporary seeding will be required.
Post Construction
BMP’s shall be maintained until final site stabilization.
E. Final Stabilization and Long-term Stormwater Quality
Final stabilization is reached when all soil disturbing activities at the site have been
completed and vegetative cover has been established with a density of at least 70 percent
of pre-disturbance levels or when equivalent permanent erosion reduction methods have
been utilized. Upon final stabilization, temporary BMP’s may be removed.
Water quality will be provided through established landscaping and pervious areas on the
site.
F. Inspection and Maintenance Procedures
Appropriate measures shall be taken to inspect and maintain existing erosion control
features, as described herein or per manufacturers specifications (whichever is more
stringent) and install new erosion control elements as needed.
The temporary BMP’s will be inspected and documented at a minimum of once every 14
days and after each precipitation or snowmelt event. Records should include complete
inspection reports for each inspection, maintenance and/or repair. A record-keeping
system is recommended in managing inspection and maintenance reports and should
include all maintenance records, spill response, weather conditions, training,
correspondence, etc.
Preventative maintenance also involves the regular inspection and testing of equipment,
timely maintenance of the equipment, and complete records of the maintenance and
inspections of the equipment. The maintenance and inspection records should be kept on
site and made available upon request.
Inspections must include the observation of the construction site perimeter, runoff
discharge points, disturbed areas, staging areas (including concrete washout areas and
fueling areas), erosion and sediment control measures identified, and any other structural
BMP’s that may require maintenance. The inspection must determine if there is evidence
of or potential for pollutants to enter the drainage system and if they should be modified,
replaced, or added to.
The following list includes some recommended maintenance procedures:
• Erosion and sediment control measures determined, upon inspection, to be in need
of repair shall be maintained before the next anticipated storm event or as
necessary to maintain continued effectiveness of erosion and sediment control
measures. If it is impractical to maintain erosion and sediment control measures
before the next storm event, maintenance should be accomplished as soon as
practical.
• Locations where vehicles enter or exit the site shall be inspected for evidence of
sediment being tracked off-site by construction traffic. Such sediment shall be
removed before it can be conveyed to the receiving storm drains or creeks.
• Seeded areas will be checked to see that grass coverage is maintained. Areas will be
watered, fertilized and reseeded as needed.
• It is the responsibility of the Operator to maintain effective pollutant discharge
controls. Actual physical site conditions or contractor practices could make it
necessary to install more control than are shown on the Erosion Control Plan. For
example, localized concentrations of surface runoff or unusually steep areas could
require additional erosion control devices. Assessing the need for, and implementing
additional controls will be a continuing aspect of the SWMP until final stabilization.
This plan intends to control water-borne and liquid pollutant discharges by some
combination of interception, filtration, and containment. Parties implementing this
plan must remain alert to the need to periodically refine and update the plan in
order to accomplish the intended goals.
• Sediment that has escaped the construction site must be removed at a frequency
sufficient to minimize off-site impacts.
G. Erosion Control Surety Calculations
Item Quantity Unit Cost Cost
Silt Fence 139 LF $3.00/LF $417
Inlet Protection 1 EA $30/EA $300
Temporary Seeding 0.29 AC $500/AC $145
TOTAL COST $862
The total erosion control cost is expected to be lower than the City of Fort Collins
minimum, therefore erosion control surety of $1500 will be required.
Appendix D
Grading Drainage and Erosion Control Plan