HomeMy WebLinkAboutNC0089729_Additional Information Received_201804247606 Whitehall Executive Center Drive, Suite 800
Charlotte, North Carolina 28273
Telephone 704-529-3200
Fax 704-529-3272
www.atcgroupservices.com
April 24, 2017
North Carolina Department of Environmental Quality
Division of Water Quality
NPDES Permit Unit
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
RE: Additional Information
NPDES Permit Application NC0089729
Myrtle/Morehead Stormwater Drainage Improvements
Management of Construction Dewatering Fluids
Charlotte, Mecklenburg County, North Carolina
ATC Project No. 199WOO1801
Dear Mr. Derek Denard:
On behalf of the City of Charlotte, Environmental Services, ATC Associates of North Carolina,
P.C. (ATC) submits the additional information related to referenced National Pollution
Discharge Elimination System (NPDES) permit application as requested in your March 5,
2018 letter. The previously submitted NPDES permit application is for the discharge of
construction-dewatering fluids generated during construction.
Note that the anticipated schedule of the planned dewatering activities within the area of the
impacted groundwater consist of two construction periods of two to four month duration,
separated by approximately twelve to eighteen months of no dewatering activities. Thus, the
duration of the project used for the Present Value of Costs Analysis (PVCA) is two years.
Additional or Revised Information
1. A Complete Engineering Alternatives Evaluation (EAA) in accordance with the EAA
Guidance Document including the following:
a. A letter indicating that the POTW is not willing to accept pre-treated groundwater.
Charlotte Water, the local Publically-Owned Treatment Works (POTW), indicated in
their letter dated March 9, 2018, that they do not accept groundwater discharges, in
accordance with the City of Charlotte’s Sewer Use Ordinance (Section 23-79 (b)(14).
A copy of the letter is included in Attachment A.
b. A present value of costs analysis (PVCA) to evaluate the economic feasibility of each
alternative, including at a minimum NPDES discharge, infiltration galleries, in-situ
groundwater remediation wells, closed-loop remediation wells, or any combinations
of these alternatives.
Estimated costs for the alternatives (Table 1) used for the PVCA are included in
Attachment B.
April 24, 2018
Page 2
c. A summary table comparing the PVCAs for all alternatives including the NPDES
discharge.
A summary of the PVCA’s (Table 2) is included in Attachment B.
d. A completed Attachment A, which is a Local Government Review Form per the EAA
Guidance Document instructions.
The Local Government Review Form along with a copy of the October 16, 2018
Engineering Alternatives Analysis and NPDES Permit Application were submitted to
Mecklenburg County on April 10, 2018 (via email) and to the City of Charlotte on April
16, 2018 (via certified mail). A copy of the notarized form from Mecklenburg County
and a copy of the Certified Mail Receipt ticket for the submittal to the City of Charlotte
are included in Attachment C. For the City of Charlotte form, ATC will submit to the
NCDEQ upon receipt of either a copy of the notarized form or the returned Certified
Mail Receipt.
2. Outfall location with latitude and longitude to the nearest second.
A revised Figure 2, Environmental Site Map indicating the latitude and longitude of the
proposed outfalls is included in Attachment D. Figure 2A, Stream Outfall Location Map
indicates the location of the stormwater system outfall to the receiving surface water body.
3. Other supporting information related to:
a. Impaired waters and total maximum daily loads (TMDLs) which may restrict discharge
conditions. Note that ATC will review the NCDEQ’s website to determine if this
applies to the planned receiving waterbodies.
The receiving body is Little Sugar Creek (Unit No. 03050103, Index No. 11-137-8a)
and is classified as an impaired water. TMDLs are listed for copper, mercury, and
fecal coliform for impaired rating, and for turbidity for supporting rating. A copy of page
130 of the 2012 North Carolina Integrated Report is included in Attachment E.
b. Determination of the presence of endangered species at the discharge location that
may result in discharge restrictions.
ATC contacted the N.C. Natural Heritage Program on April 9, 2018, with a request for
a determination of endangered species within the area of the proposed discharge
locations. According to Mr. Byron Hamstead, a response letter addressing
endangered species will be provided to ATC (with a copy submitted directly to Mr.
Derek Denard) within 30 days of ATC’s April 9, 2018 request.
Evaluation of Alternatives
The EAA (Step 3) states that “In order for the applicant to eliminate a wastewater disposal
alternative, you must either show that the alternative is technologically infeasible, or that it would
be cost prohibitive to implement relative to a direct discharge alternative. Please note that for
some alternatives, it might be easier to prove an alternative is not viable based on high cost rather
than technological feasibility.”
To facilitate review and approval of the application by the NCDEQ, the costs for the alternatives
evaluated assume that all system components would be located solely on the one parcel, and
that no offsite properties would need to be purchased. Additional comments regarding the
April 24, 2018
Page 3
alternatives to the NPDES discharge presented in the October 16, 2017 Permit Application are
presented below.
Land Application:
The soil at the site is classified as Cecil Soil, with reported infiltration rates of 0.57 inches per
hour to 1.98 inches per hour. The limiting factor is the mounding of the groundwater surface.
Assuming a depth to groundwater of 8 feet in the infiltration area and to limit the mounding to
be less than 2 feet below land surface, approximately 5.2 acres of infiltration area would be
needed for a discharge rate of 50 gallons per minute (GPM). Groundwater flow modeling
would be required for full design and permitting purposes. This does not account for possible
rainfall events during the four-week discharge period, that would likely require shut down of
the dewatering and construction activities. Additionally, the site would need to be prepared
by removing all impervious surfaces, buildings, and trees, along with surface water runoff
controls to allow for infiltration and to prevent runoff from the site.
Infiltration Galleries:
Assuming a similar area needed for infiltration galleries (drain field) as that for land application,
an area approximately 470 ft by 470 ft would be needed. Groundwater flow modeling would
be required for full design and permitting purposes. With a drain line spacing of 10 feet,
approximately 23,030 feet of drain lines would be needed, including the trunk line. The cost
estimate does not include the cost of removing the drain lines and repairing the land surface
after the project is complete.
In-Situ Groundwater Remediation Wells:
The first scenario presented in the permit application for this alternative is for chemical
injection to treat the groundwater in-situ, to reduce the contaminant concentrations to less
than the surface water quality prior to dewatering activities. Due to the uncertain timeframe
needed to reduce the contaminant concentrations by this method, this scenario is not
technically feasible within the planned project duration.
The second scenario presented for this alternative is for the treatment of the extracted
groundwater to the surface water quality standards and injection of the treated water in a
series of injections wells. Groundwater flow modeling would be required for full design and
permitting purposes. The depth of the wells would need to be deep enough to encounter
water bearing fractures of sufficient transmissivity enough to accept the quantity of water. The
cost estimate assumes six wells installed to a depth of 125 feet below land surface. There is
also the uncertain timeframe for full treatment of the groundwater prior to dewatering activities.
Closed-Loop Groundwater Remediation Wells:
No detailed cost for this alternative were estimated, due to the anticipated cost and the
uncertain timeframe to reduce the contaminant concentrations in the groundwater to be less
than the surface water quality standards. The anticipated cost of approximately $100,000 per
well (with at least four wells needed) would exceed that of the estimated cost of the infiltration
gallery alternative.
Due to the nature of construction (installation of storm pipe or replacement), limited property in
right-of-way, location of structures/personal property and temporary nature of the construction
project, these four alternatives are impractical, cost prohibitive, and not feasible.
April 24, 2018
ATTACHMENT A
POTW Letter
April 24, 2018
ATTACHMENT B
PVCA Evaluations
Table 1. Estimated Costs of AlternativesNPDES Permit Application NC0089729Myrtle/Morehead Stormwater Drainage ImprovementsCharlotte, North CarolinaATC Project Number 199WOO1801DescriptionNPDES DischargeLand ApplicationInfiltration Galleries Ex‐situ Treatment and InjectionRateTaxed(7.025%)NPDES DischargeLand ApplicationInfiltration Galleries Ex‐situ Treatment and InjectionYear 1 Capital/Upfront CostPermitting and FeesEstimate7,000$ 7,000$ 7,000$ 7,000$ Treatment System DesignEstimate5,000$ 5,000$ 5,000$ 5,000$ Groundwater Flow ModelingEstimate5,500$ 5,500$ 5,500$ Treatment System InstallationSame system for all disposal methods* Treatment System Initialization Preparation, Bag purchase, Delivery111112,094$ 1.0725 12,970.82$ 12,971$ 12,971$ 12,971$ *Treatment System PlacementInitial Placement/One Relocation 22223,500$ 7,000$ 7,000$ 7,000$ 7,000$ *Treatment System Lease Monthly 11119,693$ 1.072510,395.74$ 10,396$ 10,396$ 10,396$ *Return Freight from Site Each 11113,070$ 1.07253,292.58$ 3,293$ 3,293$ 3,293$ *System Technician (SubK)Daily (10 hr day + perdiem) 22221,050$ 2,100$ 2,100$ 2,100$ 2,100$ *System Laydown Area 50 ft by 15 ft 22225,000$ 10,000$ 10,000$ 10,000$ 10,000$ *System Cleaning & Waste DisposalBefore Returning 11114,500$ 4,500$ 4,500$ 4,500$ 4,500$ * Generator Deliver $120 each way2222120$ 1.0725 257$ 257$ 257$ 257$ * Generator Rental Sunbelt 20KW ($580/wk)4444580$ 1.0725 2,488$ 2,488$ 2,488$ 2,488$ * Generator Fuel Diesel 100 gpd, 5 days/wk, 4 wks 2000 2000 2000 20002.60$ 1.0725 5,577$ 5,577$ 5,577$ 5,577$ Environmental Technician Install and Startup 12 12 12 12 65$ 780$ 780$ 780$ 780$ Staff Scientist Install and Startup 12 12 12 12 75$ 900$ 900$ 900$ 900$ Project Manager Project Management 8888110$ 880$ 880$ 880$ 880$ Administrator Project Management 4444 50$ 200$ 200$ 200$ 200$ Daily Mileage/Equipment Install and Startup 2 250$ 500$ ‐$ ‐$ ‐$ Daily Mileage/Equipment Install and Startup 2 2 2 125$ ‐$ 250$ 250$ 250$ NPDES Discharge Piping InstallationEnvironmental Technician Install and Startup 4 65$ 260$ ‐$ ‐$ ‐$ Staff Scientist Install and Startup 4 75$ 300$ ‐$ ‐$ ‐$ Spray Irrigation System InstallationEquipment/Supplies (Est)1 3,500$ 1.0725 ‐$ 3,754$ ‐$ ‐$ Land Clearing, Erosion Controls And stormwater permitting 1 65,000$ ‐$ 65,000$ ‐$ ‐$ Environmental Technician Install and Startup 8 65$ ‐$ 520$ ‐$ ‐$ Staff Scientist Install and Startup 8 75$ ‐$ 600$ ‐$ ‐$ Daily Mileage/Equipment1 105$ ‐$ 105$ ‐$ ‐$ Infiltration Gallery InstallationSubcontractor (Est) Drainfield and piping ($15/ft) 23030 15$ ‐$ ‐$ 345,450$ ‐$ Environmental Technician32 65$ ‐$ ‐$ 2,080$ ‐$ Project Manager8 110$ ‐$ ‐$ 880$ ‐$ Administrator250$ ‐$ ‐$ 100$ ‐$ Daily Mileage/Equipment4 105$ ‐$ ‐$ 420$ ‐$ Injection Well InstallationAssume 6 wells 125 ft deep eachDriller Mobe (Est) Mobe and Well Installation 1 450$ ‐$ ‐$ ‐$ 450$ Driller Well Install (Est) 6 wells 125 ft ea @ $70/ft 750 70$ ‐$ ‐$ ‐$ 52,500$ Well Completion and piping Buried piping to each system area 1 12,000$ ‐$ ‐$ ‐$ 12,000$ Environmental Technician 1.5 days per well72 65$ ‐$ ‐$ ‐$ 4,680$ Project Manager Project Management 6 110$ ‐$ ‐$ ‐$ 660$ Administrator Project Management 2 50$ ‐$ ‐$ ‐$ 100$ Daily Mileage/Equipment9 105$ ‐$ ‐$ ‐$ 945$ ItemPage 1 of 2
Table 1. Estimated Costs of AlternativesNPDES Permit Application NC0089729Myrtle/Morehead Stormwater Drainage ImprovementsCharlotte, North CarolinaATC Project Number 199WOO1801DescriptionNPDES DischargeLand ApplicationInfiltration Galleries Ex‐situ Treatment and InjectionRateTaxed(7.025%)NPDES DischargeLand ApplicationInfiltration Galleries Ex‐situ Treatment and InjectionItemSystem O&Massume 4 weeks of O&MEnvironmental Technician 2 visits per week, 4 hrs per visit 32 32 3232 65$ 2,080$ 2,080$ 2,080$ 2,080$ Project Manager Project Management 8888110$ 880$ 880$ 880$ 880$ Administrator Project Management 2222 50$ 100$ 100$ 100$ 100$ Daily Mileage/Equipment 8 250$ 2,000$ ‐$ ‐$ ‐$ Daily Mileage/Equipment888125$ ‐$ 1,000$ 1,000$ 1,000$ Sample analysis (estimated) VOCs and other Permit Required 6 300$ 1,800$ ‐$ ‐$ ‐$ Sample analysis (estimated) VOCs and other Permit Required 6 6 6 150$ ‐$ 900$ 900$ 900$ Subtotal81,262$ 154,030$ 432,982$ 155,387$ Year 2 Recurring CostTreatment System Relocation and O&M and Removal* Treatment System Initialization Preparation, Bag purchase, Delivery111112,094$ 1.0725 12,970.82$ 12,971$ 12,971$ 12,971$ * Treatment System Relocation Initial Placement/One Relocation 2 2 22 3,500$ 7,000$ 7,000$ 7,000$ 7,000$ *Treatment System Lease Monthly 11119,693$ 1.072510,395.74$ 10,396$ 10,396$ 10,396$ *Return Freight from Site Each 11113,070$ 1.07253,292.58$ 3,293$ 3,293$ 3,293$ *System Technician (SubK)Daily (10 hr day + perdiem) 22221,050$ 2,100$ 2,100$ 2,100$ 2,100$ *System Cleaning & Waste DisposalBefore Returning 11114,500$ 4,500$ 4,500$ 4,500$ 4,500$ * Generator Deliver $120 each way2222120$ 1.0725 257$ 257$ 257$ 257$ * Generator Rental Sunbelt 20KW ($580/wk)4444580$ 1.0725 2,488$ 2,488$ 2,488$ 2,488$ * Generator Fuel Diesel 100 gpd, 5 days/wk, 4 wks 2000 2000 2000 20002.60$ 1.0725 5,577$ 5,577$ 5,577$ 5,577$ Environmental Technician 2 visits per week, 4 hrs per visit 32 32 3232 65$ 2,080$ 2,080$ 2,080$ 2,080$ Project Manager Project Management 8888110$ 880$ 880$ 880$ 880$ Administrator Project Management 2222 50$ 100$ 100$ 100$ 100$ Daily Mileage/Equipment 8888105$ 840$ 840$ 840$ 840$ Sample analysis (estimated) VOCs and other Permit Required 6 300$ 1,800$ ‐$ ‐$ ‐$ Sample analysis (estimated) VOCs and other Permit Required 6 6 6 150$ ‐$ 900$ 900$ 900$ Well Abandonment Driller Mobe Assume 6 wells 125 ft deep each 1 350$ ‐$ ‐$ ‐$ 350$ Well Abandonment ($/ft) Assume 6 wells 125 ft deep each 750 8$ ‐$ ‐$ ‐$ 6,000$ Subtotal54,282$ 53,382$ 53,382$ 59,732$ Page 2 of 2
Table 2. Summary of PVCA of AlternativesNPDES Permit Application NC0089729Myrtle/Morehead Stormwater Drainage ImprovementsCharlotte, North CarolinaATC Project Number 199WOO1801PVCA Parameters Variables NPDES Discharge Land Application Infiltration Galleries Ex‐situ Treatment and InjectionDiscount Rate r 2.25% 2.25% 2.25% 2.25%Duration of Project (yrs) n 2222Capital Cost (All Upfront/First Year Cost)Co81,262$ 154,030$ 432,982$ 155,387$ Annual Recurring Cost (Year 2) C 54,282$ 53,382$ 53,382$ 59,732$ Present Value PV 186,268$ 257,296$ 536,247$ 270,936$ Notes:See Table 2 for detailed cost breakdownPV = Present Value of Costs AnalysisPV = Co+C*(((1+r)^n‐1)/((r*(1+r)^n)))
April 24, 2018
ATTACHMENT C
Local Government Review Forms
April 24, 2018
ATTACHMENT D
Proposed Discharge Locations
with Latitude/Longitude
SOUTH BOULEVARD
CALDWELLSTREETSOUTHRENSSELAER AVENUEEAST PARK AVENUECLEVELAND AVENUE
BERKELEY AVENUETEMPLETON AVENUEEUCL
ID
AVENUEEAST KINGSTON AVENUEEAST BLAND STREETLEXINGTON AVENUEMYRTLE AVENUE0.070.0070.00070.10.010.0010.10.010.001e ee eeeeeeeeANTICIPATED DISCHARGE LOCATION #1OUTFALL LITTLE SUGAR CREEKLATITUDE:1
LONGITUDE::
ANTICIPATED DISCHARGE LOCATION #2OUTFALL LITTLE SUGAR CREEKLATITUDE:1
LONGITUDE::
ANTICIPATED SYSTEM LOCATION #1ANTICIPATED SYSTEM LOCATION #2PROJECT NO.
NOTES:
DATE
TITLE
SCALEREV. BYPREP. BYCAD FILEPCE PLUME EXTENTSTORMWATER IMPROVEMENT AREATCE PLUME EXTENTSTORMWATER PIPESTORMWATER STRUCTUREEXPLANATIONIMAGE SOURCE: NC GEOSPATIAL DATABASEDISCHARGE LOCATIONS ARE TO EXISTING
DROP INLETS OF CITY OF CHARLOTTE
STORMWATER DRAINAGE SYSTEM, WHICH
OUTFALL TO LITTLE SUGAR CREEK.
PROJECT NO.
NOTES:
DATE
TITLE
SCALEREV. BYPREP. BYCAD FILESTORMWATER IMPROVEMENT AREAEXPLANATIONIMAGE SOURCE: NC GEOSPATIAL DATABASEPROJECT AREALITTLE SUGAR CREEKOUTFALL TO TRIBUTARY OFLITTLE SUGAR CREEKLATITUDE:
LONGITUDE:
SURFACE WATER/CREEKOUTFALL LOCATION OBTAINED FROM VIRTUAL
CHARLOTTE WEBSITE (VC.CHARMECK.ORG)
April 24, 2018
ATTACHMENT E
Little Sugar Creek
Impaired Waters and TMDLs
2012 North Carolina Integrated Report 10-digit Watershed0305010301Sugar CreekCatawba River Basin AU Number Name Description Length or Area UnitsClassificationCategoryCategoryRatingUseReason for RatingParameterYear>11-137-8aLittle Sugar CreekFrom source to Archdale Rd11.6FW MilesC5>ImpairedAquatic LifeStandard ViolationCopper52008ImpairedAquatic LifeFair BioclassificationEcological/biological Integrity FishCom4s2010ImpairedAquatic LifePoor BioclassificationEcological/biological Integrity Benthos4s2008SupportingAquatic LifeNo Criteria ExceededTurbidity1t2010ImpairedFish ConsumptionStandard ViolationWater column Mercury52010ImpairedRecreationStandard ViolationFecal Coliform (recreation)4t199811-137-8bLittle Sugar CreekFrom Archdale Rd to NC 515.5FW MilesC5>ImpairedAquatic LifeStandard ViolationCopper52010ImpairedAquatic LifeFair BioclassificationEcological/biological Integrity FishCom4s2010ImpairedAquatic LifeFair BioclassificationEcological/biological Integrity Benthos4s1998ImpairedRecreationStandard ViolationFecal Coliform (recreation)4t1998SupportingAquatic LifeNo Criteria ExceededTurbidity1t200011-137-8cLittle Sugar CreekFrom NC 51 to North Carolina-South Carolina State Line3.0FW MilesC5>ImpairedAquatic LifePoor BioclassificationEcological/biological Integrity Benthos52000ImpairedRecreationStandard ViolationFecal Coliform (recreation)4t1998SupportingAquatic LifeNo Criteria ExceededTurbidity1t2000SupportingAquatic LifeNo Criteria ExceededLow Dissolved Oxygen1t12-digit Subwatershed030501030107McAlpine CreekMonday, March 25, 2013Page 130 of 554Category 5 Assessments Approved by EPA August 10, 2012