3_site_analysis.pdf

P-909 SOF SDVT2 Operations Support Facility Work Order Number: 1704761 JEB Little Creek, VA

PART 3 - CHAPTER 3 - Page 1

3.0 SITE ANALYSIS

3.01 Site Location

This project is located at JEB Little Creek in Virginia Beach, Virginia. The project is located within the peninsula surrounded by Little Creek Cove and Desert Cove and is accessed from Gator Boulevard and Intercove Road. The Conceptual Site Plan in Part 6 of the RFP disturbs approximately 9.94 acres. Project P907 is in the phase of construction and is located west of P909. Building CB127 is located northwest of P909. Building CB125 is located west of P909. Building 3802 is located south of P909. Building 3814 is located southwest of building CB 123.

Due to the proximity of the site to Norfolk International Airport, UFC 3-260-01 Airfield and Heliport Planning and Design must be referenced as it relates to “imaginary surfaces.” Contractor is responsible for being aware of any limitations on construction equipment height and for making all required submittals to the FAA.

N.T.S.

Figure 1: JEB Little Creek Enlarged Ariel Map

PART 3 - CHAPTER 3 - Page 2

N.T.S

Figure 2: JEB Little Creek Base Map

3.1 Existing Site Conditions

See the drawings in part 6, attachment A.

3.1.1 Natural Constraints

Topography:

The topography of the site is generally flat with elevations ranging from approximately 7 feet to 14 feet NAVD88. The site peaks in the middle of the peninsula and drains north, towards Desert Cove to inlet basins and west towards building CB125 where inlet basins catch the stormwater and release it north into Desert Cove.

Portions of the site are in the SPECIAL FLOOD HAZARD AREAS Without Base Flood Elevation (BFE) Zone AE (EL 8 Feet); Zone AE (EL 9 Feet); Zone X 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mile; and Zone X Area of Minimal Flood Hazard; reference the current FEMA Flood Hazard Map 5155310016G.

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Figure 3: FEMA Flood Hazard Map

Vegetation / Landscaping:

The site is currently sparsely vegetated with a few landscaping trees and is surrounded by storm water management basins to the north and south.

No eagle nests are known to occur within 1.5 miles of the project site.

Wetlands:

Delineated wetlands are not present on the site.

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Figure 4: LID/Storm water basins and Pollution Control Map

3.1.2 Man Made Conditions

Existing Vehicular Access and Circulation:

The project site will be accessed via Gator Boulevard from the access road at building CB125.

Site Utilities:

Refer to Existing Conditions Plan in Part 6.

Site Drainage & Storm Water Runoff:

Refer to Existing Conditions Plan in Part 6.

Existing Buildings:

Building CB127 is located northwest of P909. Building CB125 is located west of P909. Building 3802 is located south of P909. Building 3814 is located southwest of building CB 123. CB123, CB126, and 3884 are located on the existing site of P909.

Existing Waterfront Facilities:

PART 3 - CHAPTER 3 - Page 5

An existing quay wall is located south of project site P909. Piers 58-37 are located north and south of project site P909.

Known Contamination

Based on the findings of the preliminary Geotechnical Site Characterization (Ref. Part 6 Attachments), contaminated soil and groundwater were encountered at the project site.

Based on the findings of the preliminary Geotechnical Site Characterization geophysical survey and test pit programs (Ref. Part 6 Attachment F) metallic debris and trash were encountered at the project site.

3.1.3 Geotechnical Information and Requirements

EXISTING GEOTECHNICAL DATA

Subsurface soil information is included in Part 6 of this RFP (refer to Part 6 – Attachment F).

The soils information provided in this RFP is for reference only, and reflects the soil conditions encountered only at the locations indicated. The Government shall not be responsible for any interpretation or conclusion by the Contractor drawn from the data or information beyond the industry standard of care. Any geotechnical report accompanying the subsurface information is provided only to better convey data (boring logs, testing, etc.) or to document observed site conditions. The assumptions, analysis, and recommendations provided in any accompanying report are based on preliminary planning requirements and may not be applicable to the offeror’s design concept as the current project requirements, and assumptions may differ.

Groundwater level measurements are noted on the boring logs and the anticipated seasonal high groundwater level is noted in the geotechnical reports included within other portions of this RFP. The Contractor, in conjunction with their geotechnical engineer, is responsible for interpreting the available groundwater information and determining potential impacts related to design and construction of the design concept.

GEOTECHNICAL ENGINEERING CONSULTATION AND STUDY

The Contractor will retain a Geotechnical Engineer experienced in the geologic region and currently licensed in the state where the project is located to interpret the Government provided information as related to their design concept/bid and develop geotechnical requirements to support design and construction for the project meeting the requirements of this Proposal for bidding purposes.

The Contractor will consult with the licensed Geotechnical Engineer prior to bidding and the Contractor must include in the technical narrative section of their proposal, a statement that the site preparation, earthwork, foundation and pavement design concepts are based on the recommendations of the Contractor's Geotechnical Engineer and the RFP requirements. In accordance with FAR Subpart 9.5, Organizational and Consultant Conflicts of Interest, the Contractor is prohibited from hiring the Geotechnical Engineer who provided data, reports and any other services on behalf of the Government for this project.

After award, the Contractor’s Geotechnical Engineer (aka Geotechnical Engineer of Record) must perform a site specific geotechnical study including supplemental soil borings, in-situ testing, and laboratory analysis of representative soil/rock samples, and prepare a Geotechnical Report providing recommendations for foundation and pavement design in accordance with UFC 3-220-01 GEOTECHNICAL ENGINEERING and FC 1-300-09N NAVY AND MARINE CORPS DESIGN PROCEDURES and associated references. Calculations will be provided in the report to support all

PART 3 - CHAPTER 3 - Page 6 conclusions and recommendations.

Following submittal and Government approval of the Geotechnical Report, the Geotechnical Engineer of Record will prepare a letter for each design submittal verifying in writing that the recommendations of the Geotechnical Report have been properly incorporated in the plans and specifications and that the project information referenced in the Geotechnical Report is still valid based on the current project design. The letter prepared by the Geotechnical Engineer of Record will be included in the Basis of Design for each design submittal.

3.1.4 Existing Geologic and Geotechnical Site Conditions

The site is located in Virginia’s Atlantic Coastal Plain physiographic province. The Coastal Plain is characterized by an eastward thickening wedge of marine, estuarine, and fluvial sediments that were deposited in a series of marine transgressive-regressive cycles, or high and low stands of sea level.

These Coastal Plain soils generally consist of interbedded sands and clays of the Lynnhaven Member of the Tabb Formation, Norfolk Formation and Yorktown Formation.

Review of historical aerial photos from 1963 to present and government information indicates that the site was developed with the Buildings CB123 and CB126 in 1991 and Building 3884 was constructed in 1955.

Figure 5: JEB Little Creek Shoreline Map

Approximate Site Location

Building

CB126

Building CB123 Building 3884

Patton, Lara A CTR USN NAVFAC MIDLANT NOR (USA) Angie please verify this statement

PART 3 - CHAPTER 3 - Page 7

Figure 6: 1918 Cape Henry, Virginia Topographic Map

3.2 Site Development Requirements

3.2.1 Facility Footprint

Refer to Conceptual Site Plan in Part 6, Chapter B. Site the facility as designated in the Conceptual Site Plan shown in Part 6 of this RFP. The project site contains facility, laydown areas, parking, truck drive thru lane (design for WB-67), access roads, and sidewalks. The project adjoins CB125, 3802, and 3806;

coordination between the users is required throughout the design and construction of this project and design must coordinate between the facility traffic and parking requirements between the users of the adjacent buildings. Comply with UFC-3-201-01, Civil Engineering and all references cited therein including ASCE 24-14, for civil engineering.

3.2.2 Vehicular and Pedestrian Access and Circulation

Refer to the conceptual site layout in Part 6 of this RFP for the site development requirements. Vehicular circulation for all traffic will consist of double lane traffic flow in and around the site and parking areas.

Truck circulation (WB-67) is to be designed to enter the site from Intercove Road via Gator Blvd. It will enter the facility through the truck lane and exit the site onto Gator Blvd. via the access road entrance for CB125. The intersection of Cove Road and Intercove Road will need to be incorporated into the design utilizing the green space, off street parking area, and parking area along building 3806 to accommodate a WB-67. All truck traffic is to be prohibited from using the pier road.

The facility must be accessible by foot and accommodate pedestrian circulation. The majority of pedestrian traffic will be approaching the primary building entrance from the south direction from the new parking lot. Location of sidewalks is to be based on providing routes that are logical, safe, and provide the shortest route to the pedestrian’s destination. Consideration of the location of current and future buildings and improvements must be considered when locating pedestrian routes.

Approximate Site Location

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Note that the conceptual site layout attached in Part 6, of this RFP is for informational purposes only.

Provide a site design that meets all requirements in this RFP including location and size of stormwater management features, utilities layout and connection, sidewalks, traffic marking, fencing, ATFP, landscaping, tree mitigation, etc.

3.2.3 Demolition

Site demolition includes but not limited to: removal of building CB123, building CB126, building structure 3884, building 3814, gravel pavements, chainlink and ornamental fencing, deadmen, asphalt pavement and concrete, light poles, and a lift hoist system. Utility demolition includes but not limited to the removal of electrical and communication lines, underground steam lines, water and sanitary sewer lines. All utility demolition is to be demolished back to their main distribution points. Building 3884 is to be demolished and all electrical utilities rerun through a pad mounted switch station that must comply with all flood mitigation measures included in ASCE 24-14.

Figure 7: Site Aerial

3.2.4 Site Layout

A new building will be constructed in the eastern area of the site, at the intersection of Signal Point Road and Intercove Road. The current site plan shows the building offset eighty-three feet from Signal Point Rd. and 60 feet from Intercove Rd. to allow room for a stormwater facility, grading from road to finish floor elevation, ADA compliant sidewalks, and ATFP purposes. Locate the P909 building in a suitable place in the designated area, while providing sufficient space in the laydown area to accommodate the required equipment and allow maneuverability of the WB-67 through the truck access lane. Provide a heavy duty

PART 3 - CHAPTER 3 - Page 9 concrete laydown area on the west east side of the building (100 ft. by 130 ft. min. requirement 3239 SY).

Provide vehicular access for the WB-67 on the south side of the building off Intercove Rd. and have the vehicle be able to exit the site onto Gator Blvd. The truck thru-lane must be 40 ft. wide as it approaches the building of P909 for future sheltered construction not part of this project. Provide an intersection upgrade to accommodate a WB-67 at the intersection of Cove Road and Intercove Road. Approach to the intersection will need to be upgraded to keep traffic off of the pier road. Turning radius and vertical alignment of the road must be designed to accommodate the WB-67 vehicle. The conceptual site plan assumes maneuverability. Contractor must verify and confirm the vehicle is able to maneuver into the site.

Provide a parking lot on the southwest side of the site with access from Intercove Rd and Gator Blvd.

The POV parking lot must accommodate a minimum of 80% of the building occupancy. The overall layout, drive aisles, entrance road, parking, dumpster pad and enclosure with masonry wall with precast caps, vehicle and pedestrian circulation areas shall comply with SDDCTEA Pamphlet 55-17 and landscape UFC for heat island mitigation. Provide pedestrian access from the parking lot south of site P909/Building 3802 parking.

Site signage and markings are to comply with UFC-3-201-01 and the IAP. Provide primary vehicle direction, secondary vehicle direction, and street signs at the four intersections affiliated with the construction of P909.

3.2.5 Finished Floor Elevation

The minimum finished floor elevation for the building and utility pads must be 11.0 feet based on the NAVD88 vertical datum. The determination for the finished floor elevation was derived by using the Freeboard method and the DoD Regional Sea Level (DRSL) approach located in UFC 3-201-01 change 5.

The FEMA flood map shows it in the 0.2% annual chance flood hazard, areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mile – Zone X. It also comes very close to Zone AE (EL 8) which is a special flood hazard area. Reviewing the FEMA maps and following the design criteria within the UFC noted above, using section 2-1 and determining this building a high risk, non-essential facility category 3, 3a (table 2-1 in section 2-7.1) the Free board approach was determined for the Finished Floor Elevation. Using the Base Flood Elevation (BFE) determined by using the existing survey dated from P907 and the GRX website, the determined elevation is to be around 9 (NAVD 88) for the current site. The table below will illustrate the FFE and DRSL approach.

For the Freeboard method, minimum FF elevation = 9 +2 = 11 feet NAVD88.

For the DRSL method (attached) minimum FF elevation = 8.7 feet NAVD88.

The Freeboard method governs; minimum FF elevation = 11 feet NAVD88.

3.2.6 Landscaping

Landscaping must comply with UFC 3-201-02, Landscape Architecture, the Naval Amphibious Base Little Creek Installation Appearance Plan (IAP) and consist of native species and meet Bird Aircraft Strike Hazard (BASH) requirements.

See Part 3 6 ESR G2050 and ESR G05005 for specific Landscape Requirements. Follow all environmental requirements outlined within the NEPA Categorical Exclusion document included in Part 6.

3.2.7 Utilities

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Design and construct the new utility system to minimize interruption of the site and adjacent buildings while meeting basic functional criteria and economizing cost. Place utilities underground in corridors when possible to minimize cost and effort of performing maintenance and to minimize environmental disturbance. Avoid any service interruption to adjacent facilities to the greatest extent possible. Any planned outages must be coordinated with base utilities personnel.

Provide complete analysis, design, and construction of all necessary improvements needed to achieve the required fire flows and water flows for this project. A fire pump will be required for this project.

Natural Gas

Natural gas will need to be extended to the site. A new 6 inch gas line should run from Gator Blvd. via Intercove Road to P909. Refer to Existing Conditions Plan in Part 6.

Water Distribution

Water service for the P909 Facility will extend from the 12-inch waterline north of P909 that runs parallel with Signal Point Road to provide domestic and fire service. The 12-inch water line that services building CB125 will need to be tied into from the water service line that feeds building 3802 to form a loop for P909. All extensions must be sized to serve all buildings for this area. Water service must comply with UFC 3-201-01, local and state regulations.

Additional criteria that must be considered by the contractor:

1. This project requires the installation/testing of backflow prevention devices on potable water lines in accordance with the Safe Drinking Water Act. Coordinate with Water Quality Manager, EQB or Public Works Division, Operations Branch.

2. All construction must be at least 200 feet from any existing or proposed drinking water supply wells.

3. Reduction of Lead in Drinking Water Act: Installation or repair of any piping, fittings, fixtures, solder or flux providing water for possible human consumption must be "lead-free" as defined by the Reduction of Lead in Drinking Water Act (RLDWA). The RLDWA revised the definition of lead free to a weighted average of 0.25% of the wetted surfaces of plumbing products. A methodology for calculating the weighted average of wetted surfaces can be found at www.epa.gov.

Sanitary Sewer

It is anticipated that a gravity system will be installed to collect flow from the building to the existing manhole located at the northeast corner of Building 3802. If the anticipated flow overwhelms the gravity sanitary system or does not have enough grade to reach this manhole then an alternative route for the sanitary sewer line will need to be routed to the nearest gravity sewer manhole which is located approximately 100 feet east from P909. The outflow from this manhole will likely need to be upgraded for anticipated flows. Designer of Record (DOR) must verify that the existing gravity system has the capacity to accept the proposed flow from P909 in addition to the existing flow from the adjacent buildings, for any path selected.

3.2.8 Stormwater

The site mostly drains north to the Desert Cove channel. A slight portion of the site drains south where the site meets Gator Blvd. A storm drainage system shall be designed and constructed to collect and convey the 10 year storm flow from the building, parking lots and other new impervious areas into proposed Stormwater Control Measures (SCM). Subsurface precast concrete structures such as catch basins and drop inlets will collect stormwater and reinforced concrete pipe (RCP) with watertight joints where appropriate will convey the stormwater towards the stormwater SCM which will detain and treat the

PART 3 - CHAPTER 3 - Page 11 stormwater before it is discharged towards the nearby waterway. Stormwater checkvalves will need to be implemented into the outfall structures along with embankment core material. Roof downspouts may tie directly to drainage structures underground while others may discharge onto splash pads at grade.

The use of grassed swales, pre-treatment areas, and other low impact stormwater strategies throughout the site are encouraged, where appropriate. The stormwater SCMs must be designed to meet the Virginia Department of Environmental Quality’s (VADEQ) regulations for stormwater detention and water quality.

While specific SCM devices are not required at Little Creek, the conceptual plans utilize sand filters and dry swales. Subsurface basins can be utilized but only for storage purposes. The goal is to provide functioning and compliant devices which are not maintenance intensive, nor require specialized or propriety materials. A 3rd party inspector is recommended to be specified for the installation of SCMs. Do not allow the conversion of sediment traps into infiltration SCMs. The sediment trap should be separate from the SCM to protect against premature failure. Permeable paving is not a preferred strategy.

Overland relief for large storm events shall be analyzed. Calculations must demonstrate that the 100-year storm routed through proposed stormwater management features will not reach higher than 1 foot below the Finish Floor Elevation of this, or adjacent buildings. Demonstrate that the 100-year storm routed through proposed stormwater management features will not flood critical vehicle or pedestrian pathways.

Additional criteria that must be considered by the contractor:

1. Project involves the disturbance of over 5,000 square feet. Therefore, requirements under Section 438 of the Energy Independence and Security Act (EISA) will be enforced. The policy, directs all DoD construction projects and redevelopment projects with footprints greater than 5,000 square feet to implement Low Impact Development (LID) techniques to maintain predevelopment hydrology to the maximum extent technically feasible. Coordinate with Water Quality Manager, EQB or Public Works Division, Operations Branch.

2. Project involves the disturbance of 1 or more acres of land. It requires State permitting through the Virginia DEQ and the design/construction of approved SCMs. Coordinate with Water Quality Manager, EQB and the Storm Water Manager, ECB.

3. If additional new built-upon area (BUA) above and beyond the existing amount is proposed, then at a minimum, a high density SCM is required to treat that runoff from the new BUA. If the existing BUA within that drainage area and its runoff cannot be regraded or rerouted, then the proposed SCM must be designed to accommodate all the runoff within its drainage area. A full stormwater permit application will be required. Coordinate with Water Quality Manager, EQB or Public Works Division, Operations Branch.

Coordinate with Public Works Design Branch. Provide a complete stormwater management design that meets or exceeds UFC 3-210-10 Low Impact Development, UFC 3-201-01 Civil Engineering, and Virginia Stormwater Management requirements. Provide calculations to demonstrate compliance with all three criteria. Stormwater BMPs serving the building and laydown areas shall be linear and surround the building and laydown areas. Refer to the conceptual stormwater layout in Part 6 of the RFP. Maintain existing drainage patterns. It is anticipated that stormwater BMPs will be located in the parking lot footprint and surround the building and laydown areas due to topography and existing drainage patterns.

The stormwater BMPs will be designed to meet the Virginia Department of Environmental Quality’s (VADEQ) regulations for stormwater detention and water quality.

3.2.9Erosion Control

To prevent potential erosion and sedimentation from entering the surrounding waterways, numerous erosion control methods and practices shall be utilized. A stone construction entrance will be placed at the proposed site entrance off Gator Boulevard to serve the site. A sediment basin with skimmer outlets and riser, if required, shall be provided in the initial construction phase. This sediment basin must be separate from any proposed stormwater SCM. The conversion of a sediment trap or basin to a stormwater SCM is not allowed. Basins may be constructed before the site is cleared and temporary swales graded to direct sediment laden stormwater towards the basin. A temporary construction fence should be installed around the entire limits of disturbance. Silt fence and silt fence outlets shall be used

PART 3 - CHAPTER 3 - Page 12 around the perimeter of the of the construction sites to prevent sediment from exiting the disturbed areas.

A double row of silt fence should be used along the wetland buffer. The site will then be cleared and graded once these erosion control measures are in place and have been approved by the local erosion control inspector representing VA DEQ. Once stormwater structures are installed and brought to grade, inlet protection shall be provided at all inlets to prevent sediment from entering the storm system.

The site will be paved and areas will be stabilized with vegetation near the completion of the project.

Additional criteria that must be considered by the contractor:

1. Ensure sediment does not leave a construction site of any size as a result of land-disturbing activities.

Coordinate with Water Quality Manager, EQB and the Storm Water Manager, ECB.

2. Project involves the disturbance of greater than 10,000 sf of land and will require a State approved sedimentation/erosion control plan.

3.2.10 Environmental Constraints

Currently available data does not indicate wetlands are present on the project site. There is an existing drainage feature collecting adjacent stormwater runoff and discharging into Little Creek Cove. This area is wooded and fenced. It is preferred that this area remain undisturbed. If wet slip access requires crossing this feature, comply with all NAVFAC, local, state and USACE requirements and procedures for the design and permitting of this crossing.

In water work is not anticipated for this project. Do not allow debris and/or fill to enter the water. Do not allow fresh concrete to enter the harbor during all concreting work.

Vegetation clearing activities must be conducted in late fall through the winter. The survey boundary and nest locations must be surveyed with a Global Positioning System (GIS) and placed into an appropriate GIS geodatabase. The GIS data must be compliant with the current Navy Data Model Standard Environmental Module.

Additional environmental requirements are listed within the NEPA Categorical Exclusion document included within Part 6. If any significant changes to the design and/or location are identified, the NEPA evaluation must be conducted to ensure no additional environmental constraints and/or requirements are needed for this project. The review must be coordinated through the contracting officer to the Installation planner and environmental department.

3.2.11 Permitting and Agency Review

Identify and obtain all permits to comply with all federal, state and local regulatory requirements associated with this work. The contractor shall submit a complete “Permits Records of Decision (PROD)” form with the first design submittal package. A preliminary PROD form can be obtained in the Part 6 attachments. Contractor shall determine correct permit fees and pay said fees. Copy of all permits, permit applications, and the completed PROD form shall be forwarded to the Contracting Officer. In addition, the Contractor’s Designer of Record shall complete the NAVFAC Mid-Atlantic Utility Connection Permit Application, attached to Part 6 of this RFP, with the first design submittal package. Submit application to NAVFAC Mid-Atlantic Utilities Department, Code PW62 in addition to the NAVFAC Civil/ Mechanical/ Electrical Reviewer.

This project will disturb more than one acre, therefore coverage under the Virginia General Construction Permit will be required. The contractor shall submit an application for coverage to Virginia DEQ at least 60 days prior to start of construction. In addition, a SWPPP shall be developed to include an integrated erosion and sediment control plan. The SWPPP must be prepared prior to submitting a registration

PART 3 - CHAPTER 3 - Page 13 statement for permit coverage to Virginia DEQ. The SWPPP is to be retained at the construction site along with a copy of the permit and permit coverage letter.

Provide stormwater management that meets or exceeds UFC 3-201-01 Civil Engineering, UFC 3-210-10 Low Impact Development, and Virginia Stormwater Management requirements. Provide calculations to demonstrate compliance with all three criteria. Use the Virginia Runoff Reduction Method to demonstrate compliance with Virginia criteria. Complete and provide the appropriate Runoff Reduction Spreadsheet as part of the calculations. Also provide calculations demonstrating compliance with Virginia channel protection and flood protection requirements.

The Designer of Record shall submit the Stormwater Management design and calculations to Virginia DEQ for approval. The Designer of Record shall obtain approval of the Stormwater Management design and calculations from Virginia DEQ. See Stormwater Plan Guidance for CI Community, Virginia AOR’s attached in Part 6 of this RFP for submittal procedure. Provide a copy of all submittals to Virginia DEQ, comment letters from Virginia DEQ, and approval letters from Virginia DEQ, to the NAVFAC Civil Engineer assigned to this project.

Provide complete Erosion and Sediment Control Plans that meet or exceed Virginia requirements. The Designer of Record shall submit the Erosion and Sediment Control Plans and calculations to Virginia DEQ for approval. Refer to the Erosion and Sediment Control checklist in the Virginia Erosion and Sediment Control Handbook for requirements. The Designer of Record shall obtain approval of Erosion and Sediment Control Plans and calculations from Virginia DEQ.

Provide a copy of all submittals to Virginia DEQ, comment letters from Virginia DEQ, and approval letters from Virginia DEQ, to the NAVFAC Civil Engineer assigned to this project.

3.2.12 Explosive Safety Coordination

Coordinate design and site activities with Installation Explosive Safety Officer. The inhabited building must be sited outside of the existing 110% inhabited building distance arcs surrounding the site. The explosive arcs may be provided following award.

3.2.13 Geotechnical Earthwork and Site Preparation Requirements

3.2.13.1 Basis for Bidding

Base bids on the following:

• Stripping depth of surficial soil materials in existing grassed areas: 6 inches minimum;

• Grubbing depth: 30 inches minmum;

• Perched water table depth is within 3 feet of existing grades;

• Seasonal high water table depth range is 3 feet below existing grades;

• Stabilized ground water table depth range is 5 to 6 feet below existing grades at the time of the geotechnical investigation;

• Excavated onsite soils are unsuitable for reuse as backfill and fill in structure and pavement areas and may only be reused as common fill. Imported Backfill and Fill Material must be used in all structure and pavement areas and for utility and foundation excavation backfill;

• Provide imported topsoil for all planned landscape/green space areas;

• All imported fill must be tested and accepted by the Contracting Officer prior to transportation onsite in accordance with the prescriptive 01 57 19 Specification;

• A permanent subsurface drainage system is required in planned pavement areas;

• Preloading or surcharge will be required for mitigating excessive long-term consolidation settlement associated with site grade increase, except within the building footprint;

• Existing piles are to be extracted if in conflict with planned pile locations or the planned pile

PART 3 - CHAPTER 3 - Page 14 location is to be adjusted to provide a minimum of 2 feet of horizontal clearance between the existing and new piles;A preconstruction condition survey for structures located within a 200 foot radius of the project site and ground vibration monitoring program is required for driven pile foundations;Predrilling or spudding to a minimum depth of 10 feet below existing grades is required to facilitate pile installation and lessen potential damage at all test pile and production pile locations.Sheeting, shoring and well point dewatering will be required for foundation and utility excavations that extend below the groundwater level;

• All construction dewatering effluent is to be containerized, treated, and tested prior to onsite discharge in accordance with the prescriptive 01 57 19 Specification;

• All surplus excavation spoils must be disposed of at a permitted landfill facility in accordance with the prescriptive 01 57 19 Specification.

3.2.13.2 Geotechnical Earthwork and Site Preparation Requirements Prepare the site in accordance with the prescriptive geotechnical earthwork and site preparation requirements, project specifications, best practices, and the local industry standard of care. The Contractor’s Geotechnical Engineer must monitor stripping operations on a full time basis. Stripped surficial soil materials will be properly disposed of as specified and imported topsoil will be provided for the project where needed.

The underlying soils that will be exposed after completion of site stripping, demolition operations and excavation to planned subgrade elevations will have a tendency to become softened and unstable when saturated and worked by equipment. The Contractor shall anticipate these marginal subgrade support conditions and incorporate measures into his design and construction procedures to obtain required soil support while maintaining progress for completion on schedule. Construction traffic will not travel directly on exposed subgrades. The Contractor will construct haul roads as necessary to facilitate construction traffic access across the site and protect the underlying subgrade from deterioration. The Contractor will be responsible for the cost associated with any necessary measures to repair subgrades deteriorated from exposure to construction traffic and/or standing water. Determination of any unsuitable subgrade conditions beyond base bid removal requirements and need to implement remedial measures will be made by a NAVFAC Geotechnical Engineer and subject to the approval of the Contracting Officer.

Provide control of groundwater and surface water encountered during construction. Provide temporary dewatering and positive site drainage as needed to prevent conditions that will promote deterioration of exposed subgrades and open excavations, and prevent interruptions to the progress of construction.

Install and maintain all necessary temporary water containment facilities, channels/ditches, and diversions for groundwater and surface water control during the course of construction including all necessary temporary environmental controls. Provide a multiple well point dewatering system for any utility or foundation excavations that extend down to and below the groundwater level.

The site contains existing structures, surface pavements, and above and below ground utilities that will require demolition and removal prior to earthwork operations under this contract. It is noted that the required removal depth of the existing site features should be expected to be highly varying. It is reasonable to anticipate that excavations made in areas of known prior development will encounter additional materials beyond what are specifically indicated on the test boring records that will need to be removed.

Imported Select Material and Backfill and Fill Material will be required for filling all undercut excavations, grubbing excavations, excavations resulting from the demolition of existing utilities/foundations as well as new utility/ foundation excavations within the planned building and pavement areas, and for grading fill in pavement and building areas. Provide imported Select Material beneath all pavements. Provide imported Select Material or Backfill and Fill Material in all other structure and pavement locations. Select Material must meet ASTM D2487 classification symbols GW, GP, SW, SP, and SP-SM with not more than 12 percent passing the U.S. No. 200 sieve by ASTM D1140 and plasticity index not greater than zero by ASTM D4318. Backfill and Fill Material must meet ASTM D2487 classification symbols GW, GP, SW, SP, SP-SM, and SM and have a maximum of 20 percent passing the U.S. No. 200 sieve by ASTM D1140 and maximum liquid limit of 25 and maximum plasticity index of 6 by ASTM D4318.

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Stormwater embankments must be designed and constructed using the following material parameters.

Key trench and embankment core fill must meet ASTM D2487 classification symbols CL or SC with a minimum of 30 percent fines. The remainder of the embankment must be constructed with satisfactory material.

Excavated on-site soils may only be reused as common fill beyond the limits of surface bearing structures (i.e. pavements, buildings, etc.) provided it meets the project requirements. All soil material shall exhibit the characteristics required to compact the soil to the density and performance specified for the intended locations. Excavated on-site soils will be amended (i.e. with lime, cement, or blended with imported structural materials, etc.) as necessary to facilitate reuse as common fill. All fill and backfill materials will be moisture conditioned prior placement and compaction to within ± 2 percent of the optimum moisture content as defined by ASTM D 1557.

Satisfactory Materials are any materials classified by ASTM D 2487 as GW, GP, GM, GP-GM, GW-GM, GC, GP-GC, GM-GC, SW, SP, SM, SW-SM,SC, SW-SC, SP-SM, SP-SC, CL free of debris, roots, wood, scrap material, vegetation, refuse , soft unsound particles, and frozen, deleterious, or objectionable materials. . Unless specified otherwise, the maximum particle diameter shall be 3 inches. All fill and backfill material will be moisture conditioned prior to placement and compaction to within ± 2 percent of the optimum moisture content as defined by ASTM D 1557.

Unsatisfactory Materials are any materials which do not comply with the requirements for satisfactory materials. Unsatisfactory materials also include man-made fills, trash, refuse, or backfills from previous construction. Unsatisfactory material also includes material classified as satisfactory which contains root and other organic matter, frozen material, and stones larger than 6 inches. The Contracting Officer shall be notified of any contaminated materials.

The Contractor will be responsible for maintaining erosion control measures, preventing segregation, and moisture conditioning for any excavated onsite soil and aggregate materials and any imported soil and aggregate materials stockpile onsite.

All excavated materials which cannot be reused on the project (surplus soil) must be transported to an approved offsite solid waste disposal facility holding a valid permit from the Commonwealth of Virginia.

Refer to RFP Part 2, Specification 01 57 19 TEMPORARY ENVIRONMENTAL CONTROLS. No surplus material will leave Government property without written approval of the installation Environmental Hazardous Waste Managerand the Contracting Officer. The Contractor is responsible for all costs associated with all required representative analytical testing management, documentation, appropriate storage, transportation, and disposal of surplus excavation spoils.