HomeMy WebLinkAboutWPO201600022 Plan - E&S Narrative Erosion Control Plan 2016-03-23 E O SION SEDIMENT CONT OL NA
Harper - Shelton Mill
Albemarle County, Virginia
March 23, 2016
Prepared by:
FSE!! A CONCEPTS, PC.
2046 Rock Quarry Road
Louisa, Virginia 23093
(434) 531-3600
License No. 39
Project Description
The purpose of this application is to permit residential redevelopment on a small portion of a
large, agricultural property. The redevelopment includes demolition of one or more out-buildings
and portions of the main house. Also included are removal of sections of existing tar and chip
driveway, a pool and patios and removal of selected vegetation. Implementation of this plan is
intended to preclude sediment from exiting the property via runoff and onto an adjacent roadway
by means of vehicular traffic.
The property is zoned Rural Agricultural (RA). This narrative is to accompany the Erosion &
Sedimentation Control Plan submitted to Albemarle County. It is anticipated that the project will
begin construction Spring of 2016 and encompass roughly one year. 1.5 acres of the 269-acre
site resides within the limits of work. The developed condition will result in 1/2 acre of
impervious surface consisting of all buildings, paving and patios. This represents less than 1/10
acre increase in impervious surface.
Existing Site Conditions
The farm lies south of Route 250 and north of Interstate 64 near Brownsville. The portion of the
farm involved in this project is the grounds surrounding the original homestead and is largely
open lawn area with specimen tree and shrub plantings. Topography is a varied from gentle to
rolling and draining in all directions except east. The main house resides just west of a high
point. There is only one well-defined swale located southwest of the driveway. Otherwise the
land drops off consistently and in a divergent manner in all directions. Although the limits of
work are considered open area the homestead grounds are surrounded by woodland. Stockton
Creek and its tributaries flow throughout the 269-acre farm and certain sections have 100-year
flood plain associated with them. However, the creek and its floodplain are quite distant from the
limits of work. There are no erosion issues present on the property.
Adjacent Property
The property is bounded by additional rural land in all directions.
Off-Site Areas
No off-site areas involved.
Soils
According to the soils survey of Albemarle County, the soil types on the subject site include
Ashe, Braddock and Chester loams as well as Hayesville clay loam. These soil series reside
upon or adjacent to undulating ridge-tops and they are almost all well-drained, with moderate
permeability, highly erodable, have low shrink-swell potential. Bedrock is typically encountered
at 5'.
Critical Erosion Areas
There are no critical erosion areas.
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Erosion &Sediment Control Measures
Unless otherwise indicated, all erosion and sediment control practices will be constructed and
maintained according to minimum standards and specifications of the Virginia Erosion and
Sediment Control Handbook (1992).
Construction Road Stabilization - E&S Std. & Spec. 3.03
Temporary stabilization with stone of access roads, subdivision streets, parking areas and other
traffic areas immediately after grading to reduce erosion caused by vehicles during wet weather,
and to prevent having to regrade permanent roadbeds between initial grading and final
stabilization.
Silt Fence without Wire Support- E&S Std. & Spec. 3.05
Silt Fence is proposed to capture the sediments in the sheet flow. Silt Fence shall be installed in
a sequenced manner as shown on the plan.
Rock Check Dams— E&S Std. & Spec. 3.20
Small, temporary stone dams constructed across a drainage ditch to reduce the velocity of
concentrated flows, reducing erosion of a swale or ditch. Limited to use in small open channels
which drain 10 acres or less; should not be used in live streams. Owner may choose to leave
this improvement in place after stabilization if approved by E&S agent.
Topsoiling — E&S Std. & Spec. 3.30
Topsoiling shall be installed wherever landscaping, sod or permanent seeding is proposed as
indicated on the plans.
Permanent Seeding: E&S Std. & Spec. 3.32
All areas temporary disturbed by construction and not scheduled to be placed in building,
parking lot, paving, landscape mulch or sod shall be stabilized with permanent seeding
immediately following establishment of final grades. Permanent Seeding shall be performed in
accordance with Section 3.32 of the VESCH and with a seed mix listed in Table 3.32-D.
Mulching — E&S Std. & Spec. 3.35
Mulching shall be applied in accordance with Section 3.35 of the VESCH wherever Temporary
or Permanent Seeding applications are specified. See plans.
Soil Stabilization Blankets & Matting — E&S Std. & Spec. 3.36
The installation of a protective blanket (Treatment 1) or a soil stabilization mat (Treatment 2) on
a prepared planting of a steep slope, channel or shoreline.
Management Strategies
1. Construction will be sequenced so that grading operations can begin and end as quickly as
possible.
2. Areas which are outside the construction limits and not to be disturbed shall be clearly
marked.
3. Tree protection shall be installed before any grading activities commence and before
equipment and material storage areas are established.
4. Sediment trapping measures shall be installed as a first step in grading and will be seeded
and mulched immediately following installation.
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5. Seeding, whether temporary or permanent, will follow immediately after grading.
6. The site contractor shall be responsible for the installation and maintenance of all erosion
and sediment control practices.
7. After achieving adequate stabilization, the temporary erosion and sediment controls will be
cleaned up and removed and final grades established according to the grading plan for the
project.
Stormwater Management
There is no stormwater management program proposed for this project.
Sequence of Construction
1. Install construction entrance.
2. Install perimeter silt fence serving drainage areas 1, 2, 4 and 5 and rock check dam..
3. Remove all existing tar and chip driveway sections scheduled for demolition.
4. Demolish all existing structures and other site features specified for removal.
5. Perform all grading, installation of site walls, walks, proposed building foundations and new
driveway alignments.
6. Apply construction road stabilization to all new driveway areas.
7. Apply soil stabilization matting on new slope above rock check dam.
8. Install interior silt fence serving drainage area#3.
9. Complete finish grading and install topsoil, permanent seeding and mulch measures.
Maintenance
In general, all erosion and sediment control measures will be checked daily and after each
significant rainfall. The following items will be checked in particular:
1. The pipes and culverts shall be checked each morning for sediment and debris. All locations
are to be kept tight, clean and fully operational.
2. The construction entrance shall be checked regularly. If the stone becomes clogged by mud
or sediment it shall be removed and cleaned or replaced.
3. The sediment trap will be checked regularly for functionality and sediment deposition and
maintained if necessary.
4. Seeded areas will be checked regularly to ensure that a good stand is established. Areas
shall be retreated if so determined by erosion Inspector in accordance with the Virginia
Erosion & Sediment Control Handbook.
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The contractor shall be responsible for the installation and maintenance of all erosion and
sediment control practices and restoration of any damaged areas during construction and for
any warranty period prior to transfer of responsibility to Owner.
Vegetative Practices
Permanent Seeding is part of the development proposal. Prior to seeding, all areas to be
seeded shall have topsoil applied and lime and fertilizer shall be added. Permanent Seeding
shall be in accordance with Section 3.32, using Table 3.32-D for seed selection and lime and
fertilizer applications in conformance with this same chapter of the VESCH.
Permanent Stabilization
The site is to be permanently stabilized per Vegetative Practices above.
Stormwater Considerations
There is no stormwater management program proposed for this project.
State Minimum Standards
An erosion and sediment control program adopted by a district or locality must be consistent
with the following criteria, techniques and methods:
1. Permanent or temporary soil stabilization shall be applied to denuded areas within seven
days after final grade is reached on any portion of the site. Temporary soil stabilization shall
be applied within seven days to denuded areas that may not be at final grade but will remain
dormant for longer than 14 days. Permanent stabilization shall be applied to areas that are
to be left dormant for more than one year.
2. During construction of the project, soil stockpiles and borrow areas shall be stabilized or
protected with sediment trapping measures. The applicant is responsible for the temporary
protection and permanent stabilization of all soil stockpiles on site as well as borrow areas
and soil intentionally transported from the project site.
3. A permanent vegetative cover shall be established on denuded areas not otherwise
permanently stabilized. Permanent vegetation shall not be considered established until a
ground cover is achieved that, is uniform, mature enough to survive and will inhibit erosion.
4. Sediment basins and traps, perimeter dikes, sediment barriers and other measures intended
to trap sediment shall be constructed as a first step in any land-disturbing activity and shall
be made functional before upslope land disturbance takes place.
5. Stabilization measures shall be applied to earthen structures such as dams, dikes and
diversions immediately after installation.
6. Sediment traps and sediment basins shall be designed and constructed based upon the
total drainage area to be served by the trap or basin.
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a. The minimum storage capacity of a sediment trap shall be 134 cubic yards per acre of
drainage area and the trap shall only control drainage areas less than three acres.
b. Surface runoff from disturbed areas that is comprised of flow from drainage areas
greater than or equal to three acres shall be controlled by a sediment basin. The
minimum storage capacity of a sediment basin shall be 134 cubic yards per acre of
drainage area. The outfall system shall, at a minimum, maintain the structural integrity of
the basin during a twenty-five year storm of 24-hour duration. Runoff coefficients used in
runoff calculations shall correspond to a bare earth condition or those conditions
expected to exist while the sediment basin is utilized.
7. Cut and fill slopes shall be designed and constructed in a manner that will minimize erosion.
Slopes that are found to be eroding excessively within one year of permanent stabilization
shall be provided with additional slope stabilizing measures until the problem is corrected.
8. Concentrated runoff shall not flow down cut or fill slopes unless contained within an
adequate temporary or permanent channel, flume or slope drain structure.
9. Whenever water seeps from a slope face, adequate drainage or other protection shall be
provided.
10.All storm sewer inlets that are made operable during construction shall be protected so that
sediment-laden water cannot enter the conveyance system without first being filtered or
otherwise treated to remove sediment.
11. Before newly constructed stormwater conveyance channels or pipes are made operational,
adequate outlet protection and any required temporary or permanent channel lining shall be
installed in both the conveyance channel and receiving channel.
12. When work in a live watercourse is performed, precautions shall be taken to minimize
encroachment, control sediment transport and stabilize the work area to the greatest extent
possible during construction. Nonerodible material shall be used for the construction of
causeways and cofferdams. Earthen fill may be used for these structures if armored by
nonerodible cover materials.
13. When a live watercourse must be crossed by construction vehicles more than twice in any
six-month period, a temporary vehicular stream crossing constructed of nonerodible material
shall be provided.
14. All applicable federal, state and local regulations pertaining to working in or crossing live
watercourses shall be met.
15. The bed and banks of a watercourse shall be stabilized immediately after work in the
watercourse is completed.
16. Underground utility lines shall be installed in accordance with the following standards in
addition to other applicable criteria:
a. No more than 500 linear feet of trench may be opened at one time.
b. Excavated material shall be placed on the uphill side of trenches.
c. Effluent from dewatering operations shall be filtered or passed through approved
sediment trapping device, or both, and discharged in a manner that does not adversely
affect flowing streams or off-site property.
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d. Material used for backfilling trenches shall be properly compacted in order to minimize
erosion and promote stabilization.
e. Restabilization shall be accomplished in accordance with these regulations.
f. Applicable safety regulations shall be complied with.
17. Where construction vehicle access routes intersect paved or public roads, provisions shall
be made to minimize the transport of sediment by vehicular tracking onto the paved surface.
Where sediment is transported onto a paved or public road surface, the road surface shall
be cleaned thoroughly at the end of each day. Sediment shall be removed from the roads by
shoveling or sweeping and transported to a sediment control disposal area.Street washing
shall be allowed only after sediment is removed in this manner. This provision shall apply to
individual development lots as well as to larger land-disturbing activities.
18. All temporary erosion and sediment control measures shall be removed within 30 days after
final site stabilization or after the temporary measures are no longer needed, unless
otherwise authorized by the local program authority. Trapped sediment and the disturbed
soil areas resulting from the disposition of temporary measures shall be permanently
stabilized to prevent further erosion and sedimentation.
19. Properties and waterways downstream from development sites shall be protected from
sediment deposition, erosion and damage due to increases in volume, velocity and peak
flow rate of stormwater runoff for the stated frequency storm of 24-hour duration in
accordance with the following standards and criteria:
a. Concentrated stormwater runoff leaving a development site shall be discharged directly
into an adequate natural or man-made receiving channel, pipe or storm sewer system.
For those sites where runoff is discharged into a pipe or pipe system, downstream
stability analyses at the outfall of the pipe or pipe system shall be performed.
b. Adequacy of all channels and pipes shall be verified in the following manner:
(1) The applicant shall demonstrate that the total drainage area to the point of analysis
within the channel is one hundred times greater than the contributing drainage area
of the project in question; or
(2)
a. Natural channels shall be analyzed by the use of a two-year storm to verify that
stormwater will not overtop channel banks nor cause erosion of channel bed or
banks; and
b. All previously constructed man-made channels shall be analyzed by the use of a
ten-year storm to verify that stormwater will not overtop its banks and by the use
of a two-year storm to demonstrate that stormwater will not cause erosion of
channel bed or banks; and
c. Pipes and storm sewer systems shall be analyzed by the use of a ten-year storm
to verify that stormwater will be contained within the pipe or system.
c. If existing natural receiving channels or previously constructed man-made channels or
pipes are not adequate, the applicant shall:
(1) Improve the channel to a condition where a ten-year storm will not overtop the banks
and a two-year storm will not cause erosion to the channel bed or banks; or
(2) Improve the pipe or pipe system to a condition where the ten-year storm is contained
within the appurtenances; or
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(3) Develop a site design that will not cause the pre-development peak runoff rate from a
two-year storm to increase when runoff outfalls into a natural channel or will not
cause the pre-development peak runoff rate from a ten-year storm to increase when
runoff outfalls into a man-made channel; or
(4) Provide a combination of channel improvement, stormwater detention or other
measures which is satisfactory to the plan-approving authority to prevent
downstream erosion.
d. The applicant shall provide evidence of permission to make the improvements.
e. All hydrologic analyses shall be based on the existing watershed characteristics and the
ultimate development of the subject project.
f. If the applicant chooses an option that includes stormwater detention he shall obtain
approval from the locality of a plan for maintenance of the detention facilities. The plan
shall set forth the maintenance requirements of the facility and the person responsible
for performing the maintenance.
g. Outfall from a detention facility shall be discharged to a receiving channel, and energy
dissipators shall be placed at the outfall of all detention facilities as necessary to provide
a stabilized transition from the facility to the receiving channel.
h. All on-site channels must be verified to be adequate.
i. Increased volumes of sheet flows that may cause erosion or sedimentation on adjacent
property shall be diverted to a stable outlet, adequate channel, pipe or pipe system, or to
a detention facility.
j. In applying these stormwater runoff criteria, individual lots or parcels in a residential,
commercial or industrial development shall not be considered to be separate
development projects. Instead, the development, as a whole, shall be considered to be a
single development project. Hydrologic parameters that reflect the ultimate development
condition shall be used in all engineering calculations.
k. All measures used to protect properties and waterways shall be employed in a manner
which minimizes impacts on the physical, chemical and biological integrity of rivers,
streams and other waters of the state.
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Certified Responsible Land Disturber(RLD) Statement
A certified RLD is required during all stages of construction, from the initial land disturbance
through final stabilization. The name of the project RLD shall be provided to the County
before any land disturbance may begin. Notify the office in a timely manner if the RLD
changes during the course of the project.
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Appendix