Chapter 5 Stormwater/Drainage, Water Supply, … Martha’s Vineyard Airport 5 Stormwater/Drainage,...

MVY Martha’s Vineyard Airport

5 Stormwater/Drainage, Water Supply, Wastewater 5-1

Chapter 5 Stormwater/Drainage, Water Supply, Wastewater

5.1 STORMWATER/DRAINAGE

5.1.1 Existing Drainage System The airport’s drainage system does not discharge to coastal waters or waters of the U.S. and the airport therefore is not subject technically to the National Pollutant Discharge Elimination System (NPDES). Notwithstanding, airport management has undertaken due diligence in self-compliance and has prepared a Stormwater Pollution Prevention Plan (SWPPP), a Spill Prevention Control and Countermeasures Plan (SPCCP), and an Installation Spill Contingency Plan (ISCP) for the airport. The SWPPP was developed using the requirements for the NPDES Stormwater Multi-Sector General Permit 2000 as guidance. The SPCCP utilized 40 CFR Part 112 and the ISCP utilized 40 CFR Part 109 for additional guidance. These documents (SWPPP, SPCCP, and ISCP) were prepared with the ultimate goal of aquifer protection. In preparing the SWPPP, an extensive field survey of the airport’s drainage systems was undertaken. This survey was supplemented by surveys completed for this DEIR/EA by a licensed professional land surveyor. The MVY drainage system, in its totality, was something of an unknown entity until the preparation of the SWPPP as an integral element of the recent airport master plan. In essence, the existing systems are a combination of inherited structures and drainage lines from the airport’s earliest days as a military base, supplemented by additional and even redundant systems over time. The MVY system is a group of several subsystems of varying ages and hydrologic conditions. The older systems date back to the origination of the airport as a Naval Aviation Auxiliary Station in the 1940’s, with later significant additions along runways, taxiways and aprons, added from the circa mid 1980’s to about 1995. Figure 5-1 denotes the six major drainage areas and the smaller subdrainage areas within these major areas. Appendix F describes the drainage and subdrainage areas in considerable detail. Figure 5-2A denotes the detailed catch basin rim and invert elevations, pipe sizes and slopes obtained by the professional surveyor. Figures 5-2B and 5-2C illustrate other areas of the airport with existing drainage systems.

DR. BY

CADD FILE NAME

PROJECT NO.

CHKD. BY DATE:DES. BY SCALE:

FIGURE

(617) 423-3600 FAX: (617) 423-4168 WEB: HOYLETANNER.COM

45 BROMFIELD STREET- SUITE 1001, BOSTON, MA. 02108

Hoyle, Tanner & Associates, Inc.

MARTHA'S VINEYARD AIRPORT

AIRPORT IMPROVEMENT PROGRAM

ENVIRONMENTAL IMPACT REPORT/ENVIRONMENTAL ASSESSMENT

5-2BEXISTING DRAINAGE SYSTEM

MAIN TERMINAL AREA1"=200'APRIL 2004

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TERMINAL BLDG. TOWER

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DR. BY

CADD FILE NAME

PROJECT NO.


FIGURE







5-2CEXISTING DRAINAGE SYSTEM

AIRPORT BUSINESS PARK1"=200'APRIL 2004DDS

MVYA507

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NORTH LINE RO

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EAST LINE ROAD

WEST LINE ROAD

DROP INLET (TYP.)

LEACHING CATCH BASIN (TYP.)

LEACHING CATCH BASIN (TYP.)DROP INLET (TYP.)

8-IN DIA. PERFORATED DRAINAGE PIPE

Draft Environmental Impact Report/Environmental Assessment


The entire airport property eventually drains internally through infiltration, whether the runoff/stormwater is piped to an outfall or directed to an area without drainage structures and allowed to infiltrate directly. Drainage on the site is divided into surface watersheds and watershed sub-areas based on a combination of natural topography, roadway and taxiway/runway drainage divides and site development aspects. In many cases, the surface divides based on topography and areas of contribution are juxtaposed at several concentrated outfalls. The complex interconnected drainage system also joins drainage areas that would otherwise be independent. Examples of this are evident in Drainage Area 2, where the area of contribution based on topography and the runway/taxiway configuration is altered by piped inflows from Drainage Area 3, and a piped outflow connection to Drainage Area 1. Since many of the basins in this area are infiltration structures, these flows may or may not actually travel through the connecting drainage lines and thus cross the “surface divides.” Notwithstanding the surface hydrology, the groundwater watershed which ultimately receives all the surface flows encompasses the entire airport, eventually infiltrating to the sole source aquifer. Groundwater transport is generally from the northwest (upgradient) to southeast (downgradient).

5.1.2 Proposed Drainage System There is no surface water outflow from the Martha’s Vineyard Airport. All precipitation that falls on the airport is absorbed into the ground by infiltration. This process is important to the health of the island residents as the sole source aquifer provides much of the fresh water for the island. Therefore, as the aquifer is recharged primarily by the infiltration of water, the master drainage plan incorporates multi step procedures to ‘clean’ the runoff from the airport before it reaches the aquifer. The proposed drainage systems for the 2010 improvement program have been designed to drain effectively the airport during a 5-year storm without flooding within the drainage system, which is the FAA design standard. However, the stormwater system also will be sized to withstand a 50-year storm without any structural failure (washout, significant outlet erosion, etc.). The difference is the 5-year storm can be absorbed into the closed pipe system without significant “choking” of pipes and catch basin surcharge (overflow). A pipe system that is designed for a 5-year storm cannot absorb a 50-year rainstorm; however, the structural integrity of the stormwater system (mostly the outlets) will be protected after any flooding has subsided. In the case of the airport, there are no significant structures, i.e., dams, detention ponds, retaining walls, that could suffer major structural failures; therefore, the 50-year storm was analyzed only to ensure that overland flow, channel flow and stormwater outlets were protected to the maximum extent practicable. Utilizing the Stormwater Management - Volume One: Stormwater Policy Handbook as a design guide, the appropriate Best Management Practices (BMP’s) were selected to properly treat the stormwater in the future 2010 Build scenario. The following is a



listing/summary of the BMP’s that will be implemented in the 2010 improvement program: 5.1.2.1 Taxiway Alpha to FAA Standards Currently, the Runway 6-24 to Taxiway Alpha separation distance is approximately 368 feet, although this distance varies along the length of the taxiway; the required separation standard is 400 feet. This project will re-align Taxiway Alpha to the required 400-foot separation standard from Runway 6-24. As a part of this project, three taxiway stubs will be reshaped to meet current design standards and a significant amount of old pavement associated with the airfield’s former use as a military facility will be removed. As a result, this project will result in a net decrease of 1.44 acres of impervious area.

��Large grass infields between Runway 6-24 and Taxiway Alpha will serve to treat all stormwater runoff from these paved areas.

��Much of the stormwater is essentially clean once it enters the closed drainage system (much of the runoff travels at least 300 feet in grass infields prior to entering a catch basin). Once the water enters the closed drainage system the majority of it outlets at natural recharge basins; the remainder outlets at another recharge basin at the southeast end of the runway.

5.1.2.2 Southeast Ramp This new apron will comprise approximately 20 acres of new pavement, and will be built in two phases. Phase I (FY 2005) consists of approximately 8 acres and has its own independent stormwater management system (Figure 5-3). Phase II covers approximately 12 acres. Because of the large areas of new pavement, an extensive stormwater treatment system is being designed for this area (Figure 5-4).

��Grass infields will be incorporated into the apron layout.

��Deep sump catch basins will be provided.

��A large holding tank, designed to capture and isolate any materials in an accidental spill, will be installed at the end of the closed drainage system.

��An oil/water separator will be provided in-line with the holding tank.

��Both the holding tank and the oil/water separator will be outfitted with automated flow control devices controlling flow into the underground recharge chambers.

��A specific location on the apron with a special drainage system will be designated for deicing operations. The deicing fluids will be collected in a belowground 10,000 gallon tank and later pumped out for disposal. During non-deicing periods, a gate valve will direct collected stormwaters into the apronwide drainage system for eventual recharge to groundwater through leaching galleries. [Note: At present, MVY generates less than 500 gallons of deicing fluids annually.]

��MVY management will implement an annual catch basin cleaning program as well as a pumping/maintenance program for the oil/water separators.

DR. BY

CADD FILE NAME

PROJECT NO.


FIGURE







5-3PROPOSED DRAINAGE PLAN

SOUTHEAST APRON PHASE INOT TO SCALEAPRIL 2004

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CESSNA CITATIONCESSNA CITATION

FUTURE MULTI

-USE FACILITY

FUTURE

HANGAR

FUTURE H

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00

D D

CB 1CB 2

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DR. BY

CADD FILE NAME

PROJECT NO.


FIGURE








SOUTHEAST APRON PHASE IINOT TO SCALEAPRIL 2004

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FUTURE H

ANGAR

FUTURE H

ANGAR

EQUIPMENT

SHED

BARNES ROAD

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258+32.16

11+00

12+00

13+00

14+00

15+00

16+00

HOLDING TANK

OIL/WATER SEPARATOR

UNDERGROUND DETENTION SYSTEM

DRAIN MAN HOLE (TYP.)

CONSTRUCT NEW

CATCHBASIN (TYP.)

THIS PIPE CONTAINS TREATED WATER

(VIA INFIELD GRASS)

TRENCH DRAIN

(TYP.)

12" SD

18" SD

18" SD

24" SD

18" SD

24" SD

18" SD

30" SD30" SD

CB #113CB #112 CB #114

CB #119

CB #115CB #116

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DMH #124

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#125



5.1.2.3 Airline Road 5.1.2.4 Connector Road and Improvements to Airport Access Road

��Both roadways will have a closed drainage system with catch basins and drainage pipes leading to discharge basins. An in-line oil/water separator will be provided before the discharge basin.

Given the length of Connector Road, two open detention basins are envisioned – one near or on the grounds of the proposed County Jail, a second west of the Steamship Authority parking lot and south of the Connector Road in the Runway Protection Zone.

For Airline Road, a leaching gallery will be provided beneath a paved parking area for based aircraft/aircraft hangars.

��MVY maintenance personnel will sweep these streets when road sand build-up is deemed excessive.

5.1.2.5 Terminal 2/ARFF Building

��Terminal 2 or the GA terminal will incorporate appropriate roof designs in order to minimize potential pollutants from roof runoff.

��Parking lot size will be minimized to accommodate the minimum projected increase in demand.

��The grounds of the new terminal will be landscaped to a considerable degree, thus providing a means for the “natural” infiltration of stormwater.

��Stormwater runoff from this new building and its related parking lots and access roadways will be routed to the existing detention pond behind the existing rental car parking lot. This detention pond was designed to handle future stormwater loads and currently employs Best Management Practices and treatment methods, i.e., a large detention pond with dual in-ground recharge chambers.

5.1.2.6 Southwest Ramp The southwest apron will be enlarged and reconfigured slightly to accommodate future growth on this side of the airport. Approximately 5.4 acres of new pavement will be added (see Figure 5-5).

��To the extent practicable, a grass infield between Taxiway Alpha and the ramp will be incorporated into the apron layout.

��Deep sump catch basins will be provided.

��A large holding tank, designed to capture and isolate any materials in an accidental spill, will be installed at the end of the closed drainage system.

��An oil/water separator will be provided in-line with the holding tank.

��The holding tank and oil/water separator will be outfitted with automated flow control devices controlling flow into the underground recharge chambers.

DR. BY

CADD FILE NAME

PROJECT NO.


FIGURE








SOUTHWEST APRON1" = 300'APRIL 2004NBDNBDRMF

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.38

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HOLDING TANK

OIL/WATER SEPARATOR

UNDERGROUND

DETENTION

SYSTEM

CONSTRUCT NEW

CATCHBASIN (TYP.)

TRENCH DRAIN

(TYP.)

MODIFY EXISTING

CATCHBASIN (TYP.)

EXIST

EXISTEXIST

EXIST

EXIST

EXIST

12" SD

12" SD

12" SD12" SD18" SD

24" SD

24" SD 18" SD 18" SD30" SD

36" SD

36" SD

18"

SD

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EXIST CB

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(UNDER TRENCH)

EXIST CB

18"

SD

36" SD

EX

ITONLY

VASI

ACCESS

ROADS

FUEL

FARM

ENT

VASI

OPEN SAND

BED

SEWAGE

TREATMENT

PLANT

OAD

DETENTION

BASIN

TURF TIEDOWNS &

STUB TAXIWAYS

PAPI

N

WULTIM

ARP

3" N

17" W

EXISTING R/W 6-24

TAX

IWAY F

TAXIWAY A

TAX

IWAY C

TAXIWAY

TAX

IWAY D

PROPOSED

PROPOSED

EXISTING

EXISTING



��A specific location on the apron with a special drainage system will be designated for deicing operations. The deicing fluids will be collected in a below-ground 10,000 gallon tank and later pumped out for disposal. During non-deicing periods, a gate valve will direct collected stormwaters into the apronwide drainage system for eventual recharge to groundwater through leaching galleries.

��MVY management will implement an annual catch basin cleaning program as well as a pumping/maintenance program for the oil/water separators.

5.1.2.7 Multimodal Center/Rental Car Consolidation Facility/Remote Airport Parking The new parking lots will incorporate modern underground recharge system designs to the extent practicable. These parking lots are assumed to be pavement, as they will be servicing the public with significant and high frequency pedestrian traffic. Total paved area is calculated at 6.1 acres for the multimodal center/consolidation facility and 2.0 acres for the remote airport parking lot. The following BMP’s will be included in the parking lot designs:

��The proposed design employs a biofilter system utilizing grass treatment islands with 2-3 feet of well-drained and highly cleansing soils beneath the grass. At the bottom of the cleansing layer will be a perforated drainage pipe that will transfer the remaining stormwater to a well-drained recharge basin or chamber. The treatment islands will be landscaped.

��Rental car maintenance personnel will sweep the lots periodically when sand and grit levels are deemed high.

5.1.2.8 Future, Related or Induced Growth along the Connector Road 5.1.2.9 County Jail

��Design standards mandated by airport management will insure that all future structures along this road will incorporate appropriate roof designs in order to minimize potential pollutants from roof runoff.

��Parking lot sizes will be minimized and kept as gravel or clean stone to the extent practicable.

��Stormwater runoff from each lot will be routed away from the Connector Road storm drainage system as much as possible to avoid overburdening the collection system.

��Grass lined treatment areas will be required should the risks of generating excessive TSS and/or other pollutants be deemed high.

5.1.2.10 Summary of New Impervious Area A summary of the total new impervious area on the airport in the MVY improvement program is depicted graphically in Figure 5-6 and tabulated in Table 5-1. In total, approximately 46.6 acres of new impervious area are being added to the airport.

N

800

0800

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PAVEMENT

NEW

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FIGUREHoyle, Tanner & Associates, Inc.


DR. BYCHKD. BY DATE:DES. BY SCALE:

FILE:





IMPERVIOUS AREA

BY INDIVIDUAL PROJECT

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5-6

21.01 ACRES

1 ACRE

1.6 ACRES

.12 ACRE

2.8 ACRES

1.4 ACRES

.6 ACRES

.6 ACRES

.72 ACRE DECREASE AS RESULT OF T/W 'A

'

REALIGNMENT; DECREASE IS RESULT OF NEW

GEOMETRY FOR STUB TAXIWAYS

1 ACRE

6.1 ACRES

2.0 ACRES

2.1 ACRES

1.78 ACRES

1.83 ACRES

.41 ACRES

.33 ACRES

1 ACRE

.46 ACRES

0.02 ACRES

2.96 ACRES

100

' X 5500

' RUNWAY

C 75' X 3302' RUNWAY L

ROAD

BARNES ROAD

TAX

IWAY "A

" (EAST)

TAX

IWAY "B"

TAX

IWAY "C"

TAXIWAY "E"

TAX

IWAY "D"

TERM

INAL BLDG

.

VAS

I

WIND CONE

VOR

GL

IDE SLOPE

/RVR

EQU

IPMENT

SHED

EXISTING BICYCLE PATH

ACCESS

ROADS

FUEL

FARM

VAS

I

BARNES ROAD

OPEN SAND

BED

SEWAGE

TREATMENT

PLANT

MALSR

TOWER

EX

IST

ING

41° 23

' 09.66" N

70

° 37

' 12.27" W

EL.56.27

'

DETENT

ION

BAS

IN

TURF T

IEDOWNS &

STUB TAX

IWAYS

DETENT

ION

BAS

IN

EX

ISITNG

41° 23

' 31.90" N

70

° 36

' 40.11" W

EL.57.43

'

EX

IST

ING

41° 23

' 50.93" N

70

° 36

' 25.19" W

EL.63.03

'

NSTAR

SUBSTAT

ION

S49°18'39"E

3297.32'

DEGRADED

ASPHALT

PAVEMENT

1,000

'

EX

IST

ING ARP

VOR

STRUCTURE

RESTR

ICT

IONL

IMIT

WEST TISBURY

EDGARTOWN

WEST TISBURY

EDGARTOWN



Table 5-1 Impervious Pavement Added and Removed

Bldgs Removed Bldgs Added

Project # and

TypeFootprint

(sf)# and

TypeFootprint

(sf)

Net Change in Bldg Footprint

(sf)

Pavement Removed

(sf)

Pavement Added (sf)

Net Change

in Pavement

(sf)

Total Change in Imp. Surface (sf)

1 Taxiway A to FAA Standards 0 0 0 0 0 425,185 362,500 -62,685 -62,685

2 Southeast Ramp 0 0 0 0 0 0 805,500 805,500 805,500

3 Airline Road 0 0 0 0 0 0 45,000 45,000 45,000

4 Fire Flow Capacity to Support Hangar Development in SE Ramp

0 0 1-Pump House

480 480 0 0 0 480

5 Connector Road and Improvements to Airport Access Road

0 0 0 0 0 29,200 126,000 96,800 96,800

6 Terminal 2/ARFF including Site Work, Parking, Circulation and Curb Improvements to the Main Terminal

1-Existing ARFF

5,500 1-Addition 16,000 10,500 32,600 108,200 75,600 86,100

7 Acquisition/Relocation of Hangars, SW Ramp

4-Hngrs 21,300 0 0 -21,300 0 0 0 -21,300

8 Southwest Ramp 0 0 0 0 0 471,750 813,821 342,071 342,071

9 Fire Fighting Training Facility 0 0 0 0 0 0 20,000 20,000 20,000

10 Multimodal Center/Rental Car Consolidation Facility

0 0 1-Car Wash

1-Rental Off.

4,500 4,500 0 265,716 265,716 270,216

11 Remote Airport Parking 0 0 0 0 0 0 87,500 87,500 87,500

12 Future, Related or Induced Growth 0 0 2-SE Hngrs

1-Comm3-SW Hngrs

138,520 138,520 0 142,990 142,990 281,510

13 Obstruction Removal at Approach to Runway 6

0 0 0 0 0 0 0 0 0

14 County Jail 0 0 1-Jail 43,660 43,660 0 36,150 36,150 79,810

Total 5 26,800 10 203,160 176,360 958,735 2,813,377 1,854,642 2,031,002

acres 0.62 4.66 4.05 22.01 64.59 42.58 46.63 5.1.2.11 Consistency of the Proposed Drainage Systems with DEP Stormwater Management Guidelines. The Massachusetts Stormwater Management Handbook was used to determine the appropriate Best Management Practices to be used to treat stormwater in the MVY development program. The main focus for designing the future drainage system for MVY was obtained from the guidelines of the MA DEP Stormwater Policy Handbook. This handbook states that Best Management Practices present standards that an applicant must comply with to achieve the following program goals:



��Prevent untreated discharges to wetlands and waters.

��Preserve hydrologic conditions that closely resemble pre-development conditions.

��Reduce or prevent flooding by managing the peak discharge and volumes of runoff.

��Minimize erosion and sedimentation.

��Reduce suspended solids and other pollutants to improve water quality.

��Provide increased protection of sensitive natural resources. All of these goals were incorporated into the design of the proposed MVY stormwater management system. In particular, the main focus for the MVY system design was to minimize the loss of annual recharge to the groundwater table through the use of infiltration measures to the maximum extent possible. In all cases, the stormwater system was designed to ensure that the annual recharge from the post-development site approximated the annual recharge from the pre-development site conditions. MA DEP provides nine standards that comprise the stormwater management policy and help to achieve the above listed goals. Standards 3, 4, 8 and 9 were the primary focus for the hydraulic analyses in the master drainage plan. The remaining standards are either already being met, will not change or do not apply to MVY.

1. No new stormwater conveyances (e.g., outfalls) may discharge untreated stormwater directly to or cause erosion in wetlands or waters of the Commonwealth.

2. Stormwater management systems must be designed so that post-development peak discharge rates do not exceed pre-development peak discharge rates.

3. Loss of annual recharge to groundwater should be minimized through the use of infiltration measures to the maximum extent practicable. The annual recharge from the post-development site should approximate the annual recharge from the pre-development or existing site conditions, based on soil types.

4. For new development, stormwater management systems must be designed to remove 80% of the average annual load (post-development conditions) of Total Suspended Solids (TSS). It is presumed that this standard is met when:

a. Suitable nonstructural practices for source control and pollution prevention are implemented;

b. Stormwater management Best Management Practices (BMP’s) are sized to capture the prescribed runoff volume; and

c. Stormwater management BMP’s are maintained as designed.



5. Stormwater discharges from areas with higher potential pollutant loads require the use of specific stormwater management BMP’s. The use of infiltration practices without pretreatment is prohibited.

6. Stormwater discharges to critical areas must utilize certain stormwater management BMP’s approved for critical areas. Critical areas are Outstanding Resource Waters (ORWs), shellfish beds, swimming beaches, cold water fisheries and recharge areas for public water supplies.

7. Redevelopment of previously developed sites must meet the stormwater management standards to the maximum extent practicable. However, if it is not practicable to meet all standards, new (retrofitted or expanded) stormwater management systems must be designed to improve existing conditions.

8. Erosion and sediment controls must be implemented to prevent impacts during construction or land disturbance activities.

9. All stormwater management systems must have an operation and maintenance plan to ensure that systems function as designed.

Technical Analyses of the MVY Airport Improvement Program. The master drainage plan takes the design of drainage flows, structures and facilities at the airport into significant depth. [Note: The MVY Master Drainage Plan is contained in its entirety in Appendix F.] The plan provides the airport with an applicable design for the majority of the drainage on the airfield where construction is proposed, and provides significant improvements in existing paved areas with antiquated drainage systems, i.e., the Southwest Ramp. The plan also provides considerable details on drainage patterns and stormwater flow in areas of the airport where construction may not be eminent. In the design of the stormwater management systems, a key objective has been to maintain pre-development ground water recharge volumes in the post-development conditions (MA DEP Standard 3). In addition, Standard 4 (80% TSS removal) will be met through utilization of the proposed BMP’s. Methodology. The methodology used to analyze stormwater flows in pre-development and post-development conditions were identical. Both relied on the USDA Soil Conservation Service (SCS) TR-55 Method for determining stormwater runoff. HydroCAD Version 6.00 was employed to create models of both the pre-development and post-development scenarios. HydroCAD is a computer-aided design program for modeling the hydrology and hydraulics of stormwater runoff. It is based largely on hydrology techniques developed by the Soils Conservation Service (now the Natural Resources Conservation Service), combined with other hydrology and hydraulics calculations. For modeling purposes, the airport was divided into five zones as delineated in Figure 5-7. The “pre-development” and “post-development” scenarios used in these analyses are the Existing and 2010 Build scenarios described in Chapter 2 Project Description.

DR. BY

CADD FILE NAME

PROJECT NO.


FIGURE







5-7PROPOSED DRAINAGE AREA

DELINEATIONS1" = 700'APRIL 2004NBDNBDRMF

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I IV

II

VIII

100' X 5500' RUNWAY

C 75

' X 3302

' RUNWAY

L

EDGARTOWN - WEST TISBURY ROAD

BARNES ROAD

TAXIWAY "A" (EAST)

TAXIWAY "B"

TAXIWAY "C"

TA

TAXIWAY "D"

TERMINAL BLDG.

VASI

WIND CONEVOR

GLIDE SLOPE

/RVR

EQUIPMENT

SHED

EXISTING BICYCLE PATH

ACCESS

ROADS

FUEL

FARM

EQUIPMENT

SHED

LOCALIZER

VASI

AD

OPEN SAND

BED

SEWAGE

TREATMENT

PLANT

MALSR

TOWER

EXISTING

41° 23' 09.66" N

70° 37' 12.27" W

EL.56.27'

DETENTION

BASIN

TURF TIEDOWNS &

STUB TAXIWAYS

DETENTION

BASIN

EXISITNG

41° 23' 31.90" N

70° 36' 40.11" W

EL.57.43'

EXISTING

41° 23' 50.93" N

70° 36' 25.19" W

EL.63.03'

S49

°19

'19"E

4098.14

'

DEGRADED

ASPHALT

PAVEMENT

EXISTING ARP

WEST TISBURY

EDGARTOWN

H

26a

ACCESS ROAD TO NW RAMP

VASI

GLIDE SLOPE

/RVR

EQUIPMENT

SHED

BICYCLE PATH

ACCESS

ROADS

FUEL

FARM

VASI

OPEN SAND

BED

SEWAGE

TREATMENT

PLANT

EXISTING

DETENTION

BASIN

TURF TIEDOWNS &

STUB TAXIWAYS

DETENTION

BASIN

FREIGHT

606 spaces

456 spaces

357 spaces

124 spaces

10 spaces

100' X 5500' RUNWAY

C 75

' X 3302

' RUNWAY

L

EDGARTOWN - WEST TISBURY ROAD

BARNES ROAD

TAXIWAY "A" (EAST)

TAXIWAY "B"

TA

WIND CONE

AD

EXISITNG

41° 23' 31.90" N

70° 36' 40.11" W

EL.57.43'

DEGRADED

ASPHALT

PAVEMENT

EXISTING ARP

WEST TISBURY

EDGARTOWN

LOCALIZER



Key data inputs to the HydroCAD model are as follows:

��Martha’s Vineyard falls in a ‘type III’ rainfall distribution according to TR-55 SCS rainfall distributions.

��The intensity of rainfall events, which is dependent on the frequency of the storm, was determined from an Intensity-Duration-Frequency (IDF) curve for the area. Results of the extrapolation from the IDF curve are as follows:

Storm Duration Rainfall Event

2-Year 5-Year 10-Year 25-Year 50-Year

5 Minutes 3.40 4.20 4.90 5.50 6.00

60 Minutes 1.10 1.40 1.60 1.90 2.10

Note: Rainfall intensities (rates) are given as inches per hour.

��The time of concentration (Tc) value was assumed to be 5 minutes in most cases, except when an exceptionally large area was being modeled or when other extenuating circumstances applied (i.e., a drainage area made up completely of grassy or wooded areas).

Results. In the instance of MVY, the design intent is not to balance critical flows at certain points as much as it is to ensure that the pre-development ground water recharge volumes are maintained in the post-development conditions. Table 5-2 demonstrates that the annual recharge from the post-development site (2010 Build scenario) will approximate the annual recharge from the pre-development site conditions (Existing scenario). Conclusion. The Martha’s Vineyard Airport 2010 Improvement Program will meet all applicable regulatory programs for stormwater management. A proactive approach to BMP design has been incorporated into the Martha’s Vineyard Airport Master Drainage Plan. This plan provides the airport with guidance for future construction that will exceed all local, state and federal stormwater management goals, standards, directives and regulations.



Table 5-2 Discharge Rates in 2010 No-Build and Build Scenarios

Location/Storm Pre-Flow

(cfs)Post-Flow

(cfs)

Changein Flow

(%)

ZONE 11

5-Year Storm 37.62 53.4 42

10-Year Storm 41.62 63.0 51

25-Year Storm 43.72 67.7 55

ZONE 2

5-Year Storm 28.3 28.5 1

10-Year Storm 35.2 36.0 2

25-Year Storm 41.7 43.4 4

ZONE 3

5-Year Storm 0.03 39.1 1,302

10-Year Storm 0.15 45.6 303

25-Year Storm 0.35 48.7 138

ZONE 4

5-Year Storm 11.4 11.4 (0)

10-Year Storm 18.7 18.7 (0)

25-Year Storm 27.8 27.8 (0)

ZONE 5

5-Year Storm 19.7 19.7

10-Year Storm 24.4 24.4

25-Year Storm

[See Note 3]

26.5 26.5

Notes: 1. This table references the zone delineations depicted in Figure 5-7. The data in

Figure 5-7 are only representative of stormwater that is piped; airport areas not shaded are considered to recharge without the use of a constructed collection system.

2. Pre-development flows are lowered by overstress on the pipe network, causing unrealistically low flows to the critical point. The actual infiltration volume is effected only by the addition of new impervious material. This explains why the increase of flow in zone 3 occurs – there is more than 200 percent more pavement in this area in post-development than in pre-development.

3. No piping system exists in the pre-development condition.

As shown in the technical analyses, the annual recharge from the post-development site approximates the annual recharge from the pre-development or existing site conditions. Furthermore, the implementation of BMP’s will remove in excess of 80 percent Total Suspended Solids at each new outlet. In the particular case of the Southwest Ramp, the stormwater runoff treatment will be improved considerably over existing conditions. The proposed drainage systems are consistent with MA DEP Stormwater Management Guidelines.



5.1.3 “Reduced Build” Scenarios The Secretary’s Certificate specifically requests an analysis of the

impacts from alternative “reduced build” scenarios involving an airport expansion project consisting of a twenty percent reduction (38 acres) of additional impervious surface area, and a forty percent reduction (28 acres) of additional impervious surface area. In response to comments received from the West Tisbury Planning Board, the proponent should also evaluate an alternative “reduced build” scenario that eliminates the proposed Southeast Ramp element from the project. [Certificate, p. 3]

In presenting the required analyses, it should be noted from the outset that the proposed stormwater management systems at MVY are designed specifically to collect, treat and discharge all stormwater back to the underlying aquifer. While there is a net increase of 46.6 acres in impervious area, no stormwater is conveyed off-airport. Furthermore, paved surfaces combined with state-of-the-art collection, treatment and discharge stormwater systems are the preferred method listed in the MVY SWPPP for preventing contamination of the underlying sole source aquifer. The proposed drainage systems are consistent both with DEP stormwater management guidelines and standards and the MVY SWPPP. The area of impervious pavement to be removed in the “reduced build” scenarios of 20 and 40 percent are calculated in Table 5-3. Table 5-3 Impervious Surface to be Removed in the “Reduced Build” Scenarios

Total Impervious Area (sf) 2,031,002 2,031,002

Percent Reduction 20 40

Allowable Area, sf 1,624,802 1,218,601

Area Removed, sf 406,200 812,401

Allowable Area, acres 37.30 27.98

Area Removed, acres 9.33 18.65

5.1.3.1 FAA Pavement Design Standards Pavement design standards for runways, taxiways and aircraft parking ramps are unique and differ significantly from roadway or vehicle parking lot pavement designs. Airfield pavement design standards and criteria are contained in various FAA Advisory Circulars and provide the bases for all airport pavement designs. Advisory Circular (AC) 150/5320-6D Airport Pavement Design and Evaluation specifically provides guidance to the public for the design and evaluation of pavements at civil airports. The design standards in this AC utilize the California Bearing Ration (CBR) method of design for



flexible pavements (bituminous asphalt vs. concrete). Pavements designed in accordance with these standards are intended to provide a structural life of 20 years. This is quite different from a typical roadway whose planned structural life is generally on the order of 5-10 years. In order to achieve a 20-year life on an airfield pavement, the entire pavement system must be designed and constructed to very high strength, high durability and low frost susceptibility parameters. Airfield pavements utilize high quality base course materials that provide optimum aggregate-to gravel-to-fine-material interlock. This underlying material is compacted to 100 percent of its maximum theoretical density through its entire depth. This provides the bulk of the strength for airfield pavement, and is absolutely necessary to the success of a 20-year pavement life. The bituminous asphalt laid on top of the prepared base course is a special large-sized aggregate mix that has a low void ratio among the aggregate, sand and bitumen. This design is required to properly transfer the large loads of heavy aircraft and their resulting wheel loads. The bituminous asphalt or wearing course also is compacted as nearly as possible to 100 percent of its maximum theoretical density. Both materials must be strong and highly compacted to provide the strength and durability required to properly withstand heavy and constant aircraft loading. As important as strength, airfield pavement must remain as dry as possible underneath the bituminous asphalt in order to limit its susceptibility to frost heaving. For that reason, highly drainable subbase materials and plastic pipe underdrains are installed to enhance subsurface drainage. Because of this, airfield pavement designs far exceed regular state highway pavement designs. For the above reasons, best management practices like permeable concrete pavers, geoblock paving systems and other common methods are not appropriate for airfield paving design earmarked for the larger aircraft handled at MVY and are not allowable by the FAA. Similarly, since airfield pavement design is applicable to all areas of aircraft movement as well as parking, these methods are inappropriate for runways and taxiways as well as for aircraft parking aprons. Furthermore, any pavement that by design introduces stormwater runoff directly into the subsurface area (such as in the so-called pervious surfaces) will cause airfield pavement to fail prematurely and render it inoperable well before its required 20-year life span. Of the 14 projects in the airport improvement program, approximately 1,085,000 square feet (24.9 acres) representing 53.4 percent of the total impervious area are required to meet FAA pavement design standards (Projects #1, #2 and #8 involving Taxiway Alpha and the Southeast and Southwest Ramps). Therefore, any pavement reduction strategies, other than those intended to limit the ability of the airport to accommodate existing and projected demand for aircraft parking, must be targeted to the remaining 46.6 percent (21.7 acres) of impervious area.



5.1.3.2 Community Land Uses Of the 14 projects, four involve, directly or indirectly, land uses of benefit to the island community at large. Projects #9 Fire Fighting Training Facility, #10 Multimodal Center/Rental Car Consolidation Facility, #12 Future, Related or Induced Growth and #14 County Jail represent 652,000 square feet or approximately 15 acres of impervious area. As noted in Chapter 13 Consistency with Existing Plans, the Martha’s Vineyard Airport is seen as a valuable community resource not only for its role as a vital transportation gateway but as a centrally-located, publicly-owned land area/ development zone suitable for business/commercial development and those land uses, i.e., the county jail, preferred in more remote areas – outside of the island’s village-like town centers. MVY airport management and FAA and MAC managers and funding agents have long supported this community role. For instance, MAC provided seed funding for the very successful airport business park which today stands as a model of self-sustaining development (the lease proceeds from the business park support airport operations, maintenance and development). In addition, MAC provided state funding for the on-airport wastewater treatment plant which sustains a more intensive use of airport land, allowing the development of the airport for community-oriented uses and businesses. Of note is the fact the development of the airport business park was previously assessed and approved under an Environmental Impact Report and (Federal) Environmental Assessment filed in the early 1990’s (EOEA #6503). Development of the business park was approved and airport management continues to develop the park in accordance with development guidelines contained in the Section 61 Findings which developed from the approvals of EOEA #6503. The current status of airport management’s compliance with these guidelines is addressed in several chapters of this document. Pavement reduction strategies which limit airport management’s ability to respond to community wishes and desires run counter to its long-standing “good neighbor” policy to the island community. Furthermore, these land uses would simply be located elsewhere on the island, resulting in a gain in impervious area over the same underlying aquifer. As reported in the previous sections, airport management instead will reduce the impact of additional impervious area by adhering to the MVY SWPPP and related documents and by pursuing state-of-the-art stormwater systems which conform to or exceed DEP stormwater management guidelines. 5.1.3.3 Environmental Benefits and Enhanced Safety Margins Several of the projects result in offsetting environmental benefits, safety enhancements or both. Project #1 Taxiway A to FAA Standards is an example of a project which offers both environmental benefits and enhanced safety margins. By redesigning several related stub taxiways and removing a large area of unused, redundant pavement (a former aircraft apron in the vicinity of the existing VOR), the reconstruction of Taxiway A results in a net reduction of approximately 63,000 square feet of impervious surface. By moving Taxiway A to its FAA-required separation distance from Runway 6-24,



safety margins between aircraft operating on the runway and aircraft moving along Taxiway A are enhanced to current FAA standards. Similarly, the Connector Road permits on-airport internal movement between the main terminal area and the airport business park, thus removing airport-related traffic from the surrounding local streets and easing the burden on the key Edgartown-West Tisbury Road/Barnes Road intersection. (See Chapter 6 Parking, Traffic for documentation of delay improvement at this intersection with the Connector Road built.) Furthermore, the Connector Road project (Project #5) provides access and utilities to the proposed site of the county jail (Project #14), a desired community land use. A large component of Project #8 Southwest Ramp is essential maintenance which results in a net improvement over existing conditions. While the Southwest Ramp project entails a net increase of 342,000 square feet (7.85 acres) of pavement, it replaces a 1940’s drainage design with a state-of-the-art drainage system with provisions for spill containment and control, deicing fluid collection and removal and so on. This drainage system is designed specifically with protection of the underlying sole source aquifer in mind and is consistent with the best management designs and practices espoused in the MVY SWPPP. 5.1.3.4 Summary In summary, the airport improvement program results in 46.6 acres of new impervious area. The bulk of this area (53.4 percent) is to be built to required FAA design criteria. Of the remaining 21.7 acres, approximately 15 acres represent community land uses which benefit the at-large island community. As noted repeatedly above, all stormwater is to be collected, treated via a series of BMP's and discharged back to groundwater in accordance with and adherence to DEP stormwater management guidelines. No stormwater is conveyed to drainage channels and moved off-site. When all is said and done, existing substandard conditions reflecting outdated design standards will be replaced with new pavement designed with effective BMP's and measures specifically designed to protect the sole source aquifer. In the opinion of MVY airport management, the environmental benefits of new impervious area with the appropriate BMP’s and designs outweigh any negatives associated with additional impervious area. The issue of structure parking is addressed in Chapter 6 Parking, Traffic.



5.1.4 Adequacy of the Current SWPPP, SPCCP and ISCP The MVY Stormwater Pollution Prevention Plan (SWPPP), Spill Prevention Control and Countermeasures Plan (SPCCP) and Installation Spill Contingency Plan (ISCP) were reviewed for the following:

�� Completeness of the documents �� Identification of items which may be out of date �� Status of recommendations/progress made to complete recommended tasks �� Need for a comprehensive update

5.1.4.1 Completeness of Documents The documents prepared in 2002 presented a comprehensive listing of all MVY and tenant facilities, materials stored and their quantities and location, response equipment, and BMP’s. The drainage system was reviewed in the field and watersheds delineated. Areas were assigned ratings based on their potential for materials to contact stormwater and/or to contribute to spill events. Tenants were rated for pollution potential based on their material storage, handling and housekeeping practices, and onsite response materials. A set of recommendations for improvements to the drainage system and potential problems areas/problem tenants was set forth for the Airport to follow up on within a specified time frame. As of late 2003, the documents accurately portray the materials stored on the airport, handling and storage practices, and potential pathways to stormwater and therefore groundwater pollution. Copies of the material storage and contact information table have been distributed to all responding agencies for use in their emergency response plans. Overall, the three plans outline response practices and BMP’s to prevent spills from reaching the sole source aquifer on Martha’s Vineyard and, when updated on a consistent basis, provide the most accurate mechanism for ensuring future groundwater protection by preventing and controlling and potential releases at MVY. 5.1.4.2 Review of Document Timeliness/Need for a Comprehensive Update The 2002 documents were also reviewed for their timeliness (e.g. for outdated information or for sections requiring updates). The following section is a summary of items which need to be updated, based on document review and discussions with airport management through the fall of 2003. The Stormwater Pollution Prevention Team (SWPPT) roster is an item which requires continual updating on-premises. Airport management has indicated that the only required change is that Michael Eldridge is the new Wastewater Treatment Plant contact name. This change has been made internally to all copies of the document on-site. No reportable releases have occurred since the publication of the documents; therefore, no update of this section is needed.



New construction at the airport and in the Airport Business Park (ABP) has resulted in several new facilities and, additionally, there has been a small level of tenant turnover. Airport management has conducted tenant inspections, site plan review and reviews of material storage facilities. In addition, airport management completed an updated listing of tenant information in November 2003 to supplement information provided in the documents prepared in 2002. The continuance of on-going inspections and record updates is a critical step in aquifer protection and airport management’s vigilance in this effort is significant. MVY management has been diligent in maintaining the records required to keep the pollution prevention documents current. At this time, no additional information appears to be required. Upon completion of major construction projects at the airport, (e.g. the Southwest or Southeast Ramp), an update of the drainage map, drainage basin delineations and corresponding sections of the SWPPP and supporting documents should be completed. 5.1.4.3 Summary of Progress Made on Past Recommendations Progress has been made on most of the specific recommendations made in the SWPPP, SPCCP and ISCP in fall 2002. Table 5-4 below itemizes the recommendations from these 2002 reports and indicates the progress made, as well as the proposed deadlines for the work to be completed. Shortly after the finalization of the SWPPP and its associated documents, airport management undertook a large-scale cleanup effort in the Airport Business Park. Items such as furniture, construction debris and other macro-litter were collected and removed for proper disposal. Fences and barricades were installed as part of a security project and surveillance cameras were installed. These features, while installed primarily for security reasons, have proven to be an effective deterrent in the monitoring of illicit dumping and other inadvertent material releases. To maintain the drainage structures installed in 2002 along the primary roadways in the ABP, an annual catch basin cleaning program has been instituted as well as periodic drainage system inspections. Airport management has been conducting site visits to tenants on a quarterly basis to review housekeeping, material storage, site use and drainage issues. Modifications have been initiated for new leases, while existing ones currently will remain subject to their specified agreements until the end of their current terms. Recent site visits have been made to the main fuel storage and transfer facilities in the ABP, including the Mobil gas station. Site visits made in fall 2003 included the MVTA, Fire and Ice, Big Sky Inc., Coca-Cola, Landscope, N-Star (Mirant Canal), New England Supply, Vineyard Pool and Spa, and Osprey Trading. Documentation regarding monitoring well testing and hazardous material disposal also has been collected from several ABP facilities, as recommended in the SWPPP. New tenant and subtenant activities have been reviewed for their potential impacts, material storage and drainage systems.



Table 5-4 Summary of Progress Made on SWPPP Recommendations

SWPPP Recommendation Timeline for Completion Progress Made

Lease clause modifications regarding allowed uses, drainage requirements and material storage restrictions

Fall 2005 Modifications to leases have been made for new tenants. Opportunities for changes to current leases are being continually reviewed.

Large scale cleanup effort with focus on Airport Business Park dumping

Fall 2005 Task complete; ongoing monitoring. Significant cleanup effort removed noted debris from ABP. In addition, security measures have been taken, including installation of barricades and fencing to prevent dumping. Security cameras have been installed in ABP are now used to monitor tenants and illicit dumping.

BMP installation and available response equipment for tenants

Fall 2005 Airport has compiled a response trailer for use in the ABP and has purchased spill control devices including spill pools and absorbents (which are kept on fuel and response vehicles). Airport should still encourage BMP installation by individual tenants, as appropriate.

Fuel truck BMP’s Fall 2003 Task complete. Fuel trucks are equipped with absorbents and response materials such as spill pools. Personnel are trained for response actions. The only remaining action suggested for this recommendation would be written response instructions for fueling and response vehicles.

Location of potential off-airport outfall; determination of necessary action

Fall 2005 Outfall has been located and observed periodically during rainfall events. No outflows have been observed, even during large events. Regardless, proper discontinuation and sealing of this outfall system will be pursued in favor of infiltration.

Maintenance and replacement of Taxiway Echo drainage system

As funding is available/ development requires

No development is planned for the immediate future and no funding available to pursue reconstruction at this time.

Replacement of catch basin/manhole covers which were absent during drainage system overview.

Immediately Task complete. Missing/damaged covers were refitted and replaced.

Renovations, drainage improvements, BMP installation – Southwest Ramp

As funding is available or development requires

Task underway. In conjunction with the proposed redevelopment of this area, a new drainage system has been proposed, including O/W separators, a holding tank, shut-off valves, in-line storage, and infiltration. The existing uncontrolled and unmitigated detention area will be replaced with a proactive system to prevent possible contamination.

Drainage/BMP improvements in T-hangar area

As funding is available or development requires

Task underway. Since the SWPPP’s publication, additional drainage features have been installed in this area. In conjunction with the proposed development on the Southwest Ramp and improvements to the T-hangar area, drainage improvements and BMP’s will be installed.

Keyland Kitchens and Vineyard Decorators drainage improvements

Fall 2005 The Airport is currently in discussions with these tenants to resolve the current drainage issues onsite.

Detention/infiltration basin maintenance

As needed The basin will be maintained and sediments removed as necessary. No maintenance has been needed to date.

ABP drainage maintenance, facility improvements

Fall 2005/on-going Catch basins are being cleaned out annually by the Airport. Drainage improvements were made in conjunction with a large scale paving project in the ABP in 2002.

Survey locate/inventory drainage features

Fall 2003 In progress. Features critical to ongoing developments have been located; remaining features may be identified as funding is available.



Since the publication of the SWPPP, SPCCP and ISCP, a Drainage Master Plan for the apron/aircraft parking areas of MVY has been prepared. The plan includes preliminary designs for new, proactive drainage systems for these areas. System elements include BMP’s such as oil/water (O/W) separators, in-line storage, deep sump catch basins, holding tanks and eventual discharge to infiltration systems. The paved areas will be appropriately graded to ensure that all runoff from the paved apron areas will be directed to the stormwater system for treatment before release to the aquifer. A Construction SWPPP template for future projects on the airport has been prepared (contained in Appendix F). The SWPPP has been set up as a performance-based document with specific criteria for contractors to meet. This SWPPP will be used as a base for all work at MVY and will be supplemented by the contractors and approved by MVY’s design consultants with project- and site-specific information for future projects. In response to concerns regarding material storage at MVY, airport maintenance personnel have moved waste oil and glycol storage inside and has added secondary containment and spill pads to the drum storage areas. Finally, the quantities of these materials kept onsite have been reduced as a precautionary measure.

5.2 WATER SUPPLY As required by the EOEA Secretary, airport management has consulted with the Oak Bluffs Water District concerning the continued availability of suitable and sufficient potable water supplies to the Martha’s Vineyard Airport. The District’s Water Superintendent replied with specifics indicating that the Oak Bluffs Water District could meet all foreseeable potable water needs of the airport. Specifically, the Oak Bluffs Water District produces 360 million gallons annually, according to the Water Superintendent. Of this amount, MVY utilizes approximately 6.1 million gallons, representing 1.7 percent of the total. On peak summer days, the Superintendent reports the Water District supplied 2.44 million gallons of potable water on average in 2003. MVY utilizes approximately 60 percent of its annual total in the 4-month peak season, which yields an average of 30,000 gallons per peak season (summer) day. The peak season daily demand of the airport represents 1.2 percent of the Water District’s total peak season daily demand. Copies of the correspondence between the MVY airport manager and the Water Superintendent are contained in Appendix F.



5.3 WASTEWATER The current and projected flows for the wastewater treatment facility are summarized as follows: 1. Existing Flows Off-season Average Daily Flow (ADF) = 8,970 gallons per day (gpd) Summer ADF (July/August) = 15,060 Summer Peak Flow (Estimated) = 43,000 2. 2010 Build Scenario Design Flows Off-season ADF = 38,200 gpd Summer ADF = 73,500 The wastewater treatment facility (WWTF) discharge flow limit for the existing facility (Phase I) is 37,000 gpd as set by the MA DEP-issued Groundwater Discharge Permit, Permit No. SE #2-171, issued February 24, 2003. The flow limit for the Phase II expansion of the WWTF per the Groundwater Discharge Permit is 61,000 gpd. The limits on Total Suspended Solids (TSS) and Biochemical Oxygen Demand (BOD) are 30 mg/l for each. The limits on Total Nitrogen and Nitrate-Nitrogen are 10 mg/l for each. The WWTF utilizes rotating biological contactors (RBC’s) for biological treatment of wastewater. One (1) RBC unit is currently installed. The Phase II expansion of the WWTF would involve the addition of the second RBC unit to enable the WWTF to treat up to 61,000 gallons per day. The Phase II facilities of the other treatment process components, such as the anoxic submerged RBC’s and the secondary clarifiers, are already in place since duplication (duality) of these units was desired and considered prudent for full functionality of the WWTF, even for Phase I. At present there is one (1) ultraviolet (U.V.) disinfection unit in place. Airport management is in the process of replacing the U.V. disinfection unit with a larger unit because summertime high flows routinely reach or exceed the capacity of the existing unit. For the WWTF to handle the permitted Phase II flows up to the 61,000 gallon/day limit in the DEP effluent discharge permit, the second RBC unit will have to be furnished and installed. Space was set aside in the existing building for this purpose as part of the original design and construction of the WWTF. While this would enable the WWTF to handle the hydraulic and biological loading and meet the effluent discharge limits under the existing permit, it may not be sufficient to meet effluent discharge limitations if they were to be made significantly more stringent in the future. In view of this, a further preliminary evaluation was made to ascertain the likelihood of stricter



effluent discharge limits being imposed and what treatment technology would best be suited to meet more stringent requirements. Based on discussions with the MA DEP by study team members, the limits on TSS and BOD are not expected to become more stringent in the foreseeable future. However, the fact that the underlying aquifer is a sole source aquifer does merit consideration and caution. The MA DEP representative did indicate that in order for MVY to exceed the 61,000 gpd limit currently permitted, a new hydrogeological study would have to be completed to assess the potential impact on the groundwater. Notwithstanding concerns about the future regulated quality of the discharge effluent, the projected summer average daily flows in the 2010 Build scenario exceed the permitted discharge level of the existing WWTF. Discussions with DEP concerning the future capacity and treatment level of the MVY WWTF are continuing and will be discussed in greater detail in the FEIR/EA.



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