HomeMy WebLinkAboutNCG140376_COMPLETE FILE - HISTORICAL_20100128STORMWATER DIVISION CODING SHEET
NC6 PERMITS
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ENGINEERING, ENVIRONMENTAL
& CONSTRUCTION SERVICES
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January 28, 2010
Ms. Bethany Georgoulias
North Carolina Department of Environment and Natural Resources
Division of Water Quality
1617 Mail Service Center
Raleigh, North Carolina 27699
RE: NPDES Stormwater General Permit NCG140000 Application
Blue Ridge Concrete
P.O. Box 2594
Weaverville, North Carolina 28787
Dear Ms. Georgoulias:
LISTEN • RESPOND • PERFORM
On behalf of Blue Ridge Concrete, WPC is providing the following re-submittat and
responses to North Carolina Department of Environment and Natural Resources (NCDENR)
review comments, dated December 28, 2007. This rc-submittal was submitted and returned
in 2008 due to the property not having the appropriate Buncombe County zoning
consistency. This issue has been resolved, please see the attached Buncombe County Zoning
Consistency letter of December 11, 2009 along with the Buncombe County. With the
property now having the correct zoning, the NPDES Permit NCG140000 Application is
being resubmitted. This cover letter highlights the requested information based on the past
review. Listed below in italics are NCDENR's comments followed by the appropriate
response.
1. Plans and Specifications: These must be prepared either by a Professional Engineer
or employee internal to the company that is qualified to perform such work in
accordance with G.S. 89C-25(7). There were no plans and specifications for the
recycle ,system included with the application package, and neither plans nor
calculations were signed, sealed, and dated by a RE'. [heir four of the Final
Checklist in the application, page 5. ]
F E S 10 2010
WATER QUALITY SECTION
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RE: NPDES Stornttvater General Permit NCG 140000 Application
Blue Ridge Concrete
WPC Project No. WI'C3407.001 b8
January 28, 2010
The plans and specifications have been signed, sealed, and dated by a P.E. and are
attached. Specifications are indicated on the drawings as well as in the Stormwater
Management flan.
2. Site Map [Item six of the Final Checklist in the application, page 5.]
a. The site map does not show an outline of drainage areas, or which drainage
areas correspond to which outfall.
The drainage sheet (Figure 3) is provided in the Stormwater Management
Plan. All drainage at the facility is sheet flow towards the proposed
stormwater retention pond. The stormwater retention pond has one discharge
outfall.
b. The site map does not indicate the location of stormwater discharge oulfalls.
The stormwater discharge outfall is shown on the drainage sheet (Figure 3).
c. The site map does not specify where materials will he stored (e.g., aggregate
piles).
The site map (Figure 2) has been revised to show the locations of, all
aggregate, and sand stockpiles.
d. Will aggregate piles he irrigated? Please clarify on the nzap or in the
application, even if no discharge is expected.
The stockpiles are not to be irrigated. No discharge is expected.
e. The site map sloes not clearly indicate which areas are to he irnpervioits,
graveled, etc. Does the magenta outline of' the plant site represent the
graveled area, drainage area, or something else? There was no legend to
clarify.
A legend has been incorporated into the drawings in order to indicate property
boundaries, gravel areas, drainage contours, etc.
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RE: NPDES Stormwater General Permit NCG 140000 Application WPC Project No. WPC3407.001 b8
Blue Ridge Concrete Jamtaiy 28, 2010
WPC.,
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www.wpceng.com
3. Recycle System Design Calculations
a. There were no details of the recycle system provided. The site map just shows
a 50' x 50' "box. " Plans and specifications should be provided that showy the
structure in detail, including whether there are multiple settling cells, how the
water flows between cells, the proposed berm, whether there is any ramp
flowing into the washout system where trucks rinse out, etc. How will the
water be reused? In the plant process, for more truck washouts, and/or for
other uses?
Details of the truck wash out area are provided in Figure 4, Detail Sheet.
Section 4.2 of the Stormwater Management Plan presents the process for the
truck washout use. As presented in the Stormwater Management flan, the
truck washout system is a conical bermed basin 50 .fect in diameter and 10 feet
deep. The sides of the truck washout basin will be sloped 4:1. Each concrete
truck backs up to the berm and the driver will wash out the truck at the end of
each workday with up to 150 gallons. Wash water will be captured by and
retained in the truck washout basin. As water accumulates within the basin a
floating pump could be used to recycle water during washing operations.
Water would then be pumped from the basin- and used to help rinse sediment
from the trucks, thereby reducing the total amount of fresh water used during
the process. As needed, maintenance will occur to maintain the slope of the
basin and surrounding berm.
b. The water balance equation provided for the recycle system in not complete.
A water balance should show all Inputs -- Outputs = No Accumulation. The
Water balance presented In the application package' appears to just calculate
design volume. The calculation should demonstrate a balance between (the
water dispensed by truck washouts + design .storm volume + freeboard) and
(the hater to be used) on a daily basis. If all the water will be used again for
the same number of truck washouts, please certify this assumption about what
Page 3 of 7
RE: NPDES Stormwater General Permit NCG 140000 Application
Blue Ridge Concrete
WPC Project No. 1,VI'C3407.00168
January 28, 2010
"operating volume" means. How will the system ensure suffrcienl settling so
that the water can be re -used for its purpose?
A water balance equation is not applicable to use on the truck washout basin
and therefore it is not included in the revised Stormwater Management Plan.
c. How will the freeboard be restored after significant rain events? The
calculations assert the assumption that "operating volume is retained in the
truck washout basin and allowed to percolate into the soil within 2-5 days. "
This implies that (1) the entire operating volume will exit the system via
percolation into the soil and not by recycling and (2) the soils have an
infiltration rate to accommodate this assumption. However, there is no
information about the soils to .support this - claim. Furthermore, the
calculations go on to assume .sediment from concrete truck washing will be
allowed to build up to a depth of 8.5 feet. Haw will a washout basin with 8.5
feet of sediment and concrete residue accumulated at the bottom allow any
infiltration into the soil? Please better explain how the freeboard will be
restored, in what amount of time it is reasonable, and the basis of ' these
assumptions.
The capacity of the truck washout basin is 118 000 gallons with one foot of
freeboard, which exceeds the combined volume (22;50.O=gallons) .of 1)
washing operations, 2) one foot of freeboard required by North Carolina
Department of Environment and Natural Resources, and 3) precipitation
resulting from a 25-year 24-hour storm, 5.25 inches. The soils on -site are
Clifton Soil Series which has an infiltration rate of 0.4 to 0.5 gallons per day
per square foot. Even in the case in which the truck washout basin is tilled
with 5 feet of washout sediment, 55,000 gallons of water can be contained in
the basin while still maintaining 1 foot of freeboard. Calculations for the
truck washout system are presented in the Stormwater Management Plan.
The truck washout basin, surrounding berm, water level, and the amount of
material within the basin will be inspected and monitored daily. As discussed
in item "a" above, the wash out basin will fill over time with wash water, rain
water in varying amounts, sand, aggregate and minimum amounts of cement.
Once the wash out area has filled with five reet of wash out material, the
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Ww\N.WE.>ccn`;.corti. Page 4 of 7
RE: NPDES Stormwater General Permit NCG 140000 Application
Blue Ridge Concrete
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w\VVVNVpCCT1g.CO)11
WPC Project No. WPC340 7,00168
January 28, 2010
material will be excavated and disposed of property. If needed, the water
within the washout basin will be pumped from the washout basin into the
water storage tank to be used in the concrete batching operations. This will
accommodate settling of the truck drum contents, maintain the required free
board, as well as allow for potential water use and prevent any wastewater
effluent overflow of the washout collection area.
d. Will the truck washout recycle system include a pH adjustment system? While
overflow may happen rarely in a single rain event if the systeln is designed for
the 25 year storm, it is a possibility during the periods of chronic rain events,
Even if the absence of pH adjustment is based on the .system maintaining
enough freeboard to reasonably accornrriodate consecutive storm events, the
calculations imply this system will be earthen, and not concrete. If this is the
case, the design should incorporate pH -control to prevent adverse impacts to
groundwater. Otherwise, the design and narrative should clearly justify why
there is no pH adjustment proposed. Please provide additional information
regarding pH adjustment.
The facility's standard operating procedure will be t69-n-ariitior-pl-1, by Method
9040C, pII Electrometric Measurement, of the washout collection area on a
<weekly=basis.. Based on the measurements, Blue Midge Concrete will
manually adjust the pl-I in the basin to maintain the water within the regulated
pI-I limit of 6.0 to 9.0.
e. Please clarify i(the assumption of the number of trucks per dory is based on
an average or maximum design scenario.
The assumption of the number of trucks is based on the maximum.
4. Stormwater Retention Basin Design Calculations
a. The impervious area fraction in based on 2,344 square feel of impervious
surface. It is difficult to discern fr-oin the site plan which areas will be
irrrpervious. It is also not clear how much of the site will be paved or
graveled, and whether graveled areas are included as impervious cover in the
runoff volume calculation using the Simple Method All areas with gravel
Page 5 of 7
RE: NPDES Storm ivater General Permit NCG 140000 Application WPC Project No. WPC3407.00168
Blue Ridge Concrete January 28, 2010
WPC
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should be considered impervious. Please revise the impervious area and
design calculations if necessary.
A legend has been inserted into the stormwater drawings. The calculations
using the Simple Method have been revised to reflect the correct impervious
areas covered with gravel. PIease refer to the attached drawings and the
attached runoff volume calculations using the Simple Method.
b. If aggregate piles are irrigated at all, any flow from that area (including
stormwater that contacts the piles between irrigation) is included wastetivater.
If any wastewater flows to the retention basin, that structure must treat the
wastewater to meet effluent limits. No information was provided about
whether stockpiles will be wetted or how the retention basin will provide,
sufficient treatment to meet TSS and pHlimits if applicable.
Aggregate piles are not expected to be irrigated. The aggregate bays are
positioned with the open,.side--facing=theup-gradient_side' of the property.
Stormwater incident on or around the piles will not be capable of carrying
particulate from the piles. Therefore, the generation of `wastewater' will not
occur to the extent that it would reach the stormwater retention pond.
c. Please be aware that Weaverville is a Phase II city, and post -construction
stormwater requirements may apply to this project: Buncombe County was
recently delegated to administer the post -construction program within its
jurisdiction and within some Phase II cities; please consult the County
government about retention pond design review requirements.
WPC and Blue Ridge Concrete are in continuous contact with the Buncombe
County Planning and Development Office.
S. Erosion & Sedimentation Control Plan: No documentation verifying that an E&SC
Plan has been developed and submitted to the' Division of Land Resources (DLR) or
local delegated authority was included with the application. If an E&SC Plan is not
required, please explain why not; the site map indicates more than one acre of laird
will be disturbed by this project. `Item three of'the Final Checklist in the application,
page 5 J.
Page 6 of 7
RE: NPDES Stormivater General Permit NCG 140000 Application
Blue Ridge Concrete
WPCProject No. WPC3407.00168
January 28, 2010
The revised E&SC Plan has been provided as an attachment.
WPC will continue to work closely with Blue Ridge Concrete and NCDENR Division of
Water Quality in order to maintain compliance with state and local storinwater regulations.
Should you have any further questions, please do not hesitate to call us at (912) 629-4000.
Respectfully submitted,
WPC, Inc.
Joseph R. Ross, Jr., MS
Staff Environmental Engineer
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William S. Anderson, lll, �syRaaasa°•g'.
Vice President
Page 7 of 7
]Buncombe County {Government
Planning and Development .ton E. Creh hton
46 Valley Street, Assistant County Manager/Planning Di cctor
Asheville, NC 28801 Telephoite (8j8) 250 4830
Fax (828) 250-6086
Decenlb& 11, 2009
13Iue Ridgc; Concrete Properties, I:I.0
C/o Johnny IMarolley
P.O. Box 501
Spruce Pine, NC
Ile. Determination of Zoning Consistency
Dear wh% Maroncy,
This letter is to colltiinl that the property at 50 Nfurphy Hill Road (tax lot PIN 9744-50-
4163) was consistent with the requivenients ol'tllc Buncombe Cowity "Zoning Ordinance,
as this property was llnzoned at the tittle application was made.
This deternlillA011 is i11aCIC IRII•stRUIL to the ruling ol'the North Carolina Court of Appeals
ne«ating.the zoning of this property, effective, April, 2009.
Please contact ine if I can be of liniher assistance.
Sincerely,
�f
it in H. Cdnian, AICP, CZO
Zoning Administrator
Buncombe County Government
Planning and Development Jon E. Creighton
46 Valley Street Assistant County Manager/Planning
Asheville, NC 28801 Director
Telephone (828) 250-4830
Fax (828) 250-6086
LETTER OF PERMIT ISSUANCE
October 15, 2009
Mark Turner, President
Blue Ridge Concrete
Y.O. Box, 2594
Weaverville, NC 28787
Dear Mr. Turner,
Please find Stormwater Permit No. S-2008-035 for the Blue Ridge Concrete project enclosed. The permit
should be posted on the construction site in a location clearly visible to the public. Several procedures are
required by the Stormwater Management Ordinance (Buncombe County Chapter 26 Environment, Article VII
Stormwater Management). Please ensure the following items are completed prior to the completion of the
project.
1. An operation and maintenance manual for the stormwater management system is created for the end
user of the project. A copy must be submitted to this office. If a record plat is required it must
reference the Operations and Maintenance Manual which instructs the responsible party about annual
maintenance tasks for at least a 20 year period.
Following completion of the project the following items are required.
1. The stormwater management plan designer must submit as -built plans, or certify the existing plans as
"As -Built" if no changes have occurred, of the installed stormwater improvements.
2. The developer must disclose which party will be responsible for continued maintenance on the record
plat and on the stormwater management plan.
3. An Operations and Maintenance Agreement for the stormwater management system must be recorded.
See Division 5, Section 5 (f) of the Buncombe County Stormwater Ordinance for more information on
the elements of the agreement.
4. The approval of the stormwaterperrnit shall require an enforceable restriction on property usage that
runs with the land, such as recorded deed restrictions or protective covenants, to ensure that future
development and redevelopment maintains the site consistent with the approved project plans.
S. All maintenance documents required by this ordinance must be submitted to the Stormwater
Administrator prior to record plat approval. In the case of single family lots not requiring record plats,
documentation must be submitted to the Stormwater Administrator before building permits can be
issued.
Should you have questions or comments feet free to contact this office at (828)250-4848.
Sincere�ly
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Mike Goodson, Pi;, CPESC
Stormwater Administrator
Cc: WPC, Inc.
Buncombe County Frosion Control
Stormwater Management 250-4848
County of Buncombe
STORMWATER MANAGEMENT
Telephone: (,425) 2S0-4648
Fax: (828) 250-6086
46 VALLEY STREET
ASHEVILLE, NC 28801
LOCATIONS Murphy Dill Road
RESPONSIBLE PERSON: Mark Turner
Phone: 912/596-1609
Stox mwater Permit No.
BLUE RIDGE CONCRETE
PROJECT NAME
THIS CERTIFIES THAT A STORMWATER PERMIT HAS BEEN ISSUED FOR THE
CONSTRUCTION WORK SET OUT ABOVE.
STORMWATER ADMINSTRATOR
THIS CERTIFICATE MUST BE POSTER AT THE CONSTRUCTION SITE IN A SECURE PLACE FROM THE, TIME
WORIe, IS COMMENCED UNTIL STORMWATER ADMINSTRATOR GIVES FINAL APPROVAL.
A COPY OF TILE STORMWATER PLAN MUST BE AVAILABLE FOR THE INSPECTORS USE AT ALL TIMES.
October 15, 2009