SOW__Replace_Septic_System_at_VIP_RV_Pads_updated.pdf

CAPE HATTERAS NATIONAL SEASHORE

Fort Raleigh

Manteo, North Carolina

STATEMENT OF WORK:

Replace Septic Tank and Drainfield at VIP RV Pads on Ft Raleigh

NATIONAL PARK SERVICE

Region 2

Replace Septic Tank and Drainfield at Ft Raleigh VIP RV Pads Page 2

CAPE HATTERAS NATIONAL SEASHORE

Outer Banks Group

Statement of Work

Replace Septic Tank and Drainfield at Ft Raleigh VIP RV Pads

1.0 INTRODUCTION

The National Park Service (NPS) Cape Hatteras National Seashore (CAHA) has a requirement to replace the septic tank and drainfield at the Volunteer in the Park (VIP) Recreational Vehicle

(RV) Pads on Fort Raleigh National Historic Site (FORA).

2.0 CONSTRUCTION SITE LOCATION

The address for the project site is 1417 Pear Pad Rd Manteo, NC 29754.

3.0 BACKGROUND AND EXISTING CONDITIONS

A large concrete area located adjacent to the A-frame house at 1415 Pear Pad Rd is utilized for two RV / trailer parking pads to house NPS employees or volunteers for extended periods. The concrete pads provide Electrical, Potable Water, and Septic connection points adjacent to the pads. The septic pipes run under the concrete and immediately adjacent to the concrete park area emptying into a septic tank. The septic tank is located between the concrete pad and the driveway for the A-frame house. The septic tank effluent flows by gravity to a drainfield. The drainfield consists of several lines of perforated PVC pipe. The drainfield lines run partially beneath a sidewalk and accessible ramp leading to the A-frame entrance.

The existing tank is approximately 750 gal and drainfield measures approximately 15 ft wide and

40 ft long. The system is past its useful life, does not properly drain, and has been encroached by a nearby tree and other vegetation roots. Sewage is being pumped periodically from the septic tank to allow limited usage of the VIP Pads.

The site was examined according to North Carolina Administrative Code Title 15A Chapter 18

Environmental Health Subchapter 18A Sanitation Section .1900 Sewage Treatment and Disposal

Systems and the October 20, 2017 Memorandum regarding Permitting and Design Guidance for

Wastewater Treatment and Dispersal Systems for Recreational Vehicle Parks – Revised.

Specifically, the topography, landscape, soil wetness condition and water table depth, soil depth and restrictive horizons, daily flow rate, and setbacks for the location of tank and drainfield.

Consultation with the Dare County Public Health On Site Water Protection Branch provided helpful information on the soil type in the Housing area as a Sandy Loam. A percolation test was not conducted on site due to the sandy nature of the soil. A maximum Long Term

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Acceptance Rate of 0.8 is allowable for the drainfield sizing calculations, depending on the type of drainfield installed.

Figure 1: Vicinity of the VIP RV Pads.

Figure 2: Existing VIP RV Pads for two RVs with Electric, Water, and Septic Connections.

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Figure 3: Existing septic system overhead view

4.0 SCOPE OF WORK

Replace the septic system with a new septic system meeting North Carolina Building Code:

Plumbing Code, North Carolina Administrative Code 15A NCAC 18A, and supplemental memorandum dated October 20, 2017 regarding Permitting and Design Guidance for Wastewater

Treatment and Dispersal Systems for Recreational Vehicle Parks – Revised. New septic system shall be installed by a qualified installer according to North Carolina General Statues. Installers with qualifications from another state are acceptable.

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1. Empty existing septic tank from solids and fluids.

2. Demo existing 750 gal concrete septic tank and distribution tank.

a. Do not remove or damage or undermine existing concrete RV parking pads, the existing accessible ramp, or the adjacent house. Protect trees not designated for demolition from damage due to heavy equipment or other work.

3. Demo existing drainfield components:

a. Remove existing pipe from VIP Site 2 to the existing septic tank.

b. Disconnect the existing drain pipe from VIP Site 1 at the Wye connection with

Site 2. Ensure the disconnection is approximately 6 inches away from the edge of the existing concrete RV parking.

c. Demo the existing drainfield pipes and associated gravel / drainfield material. Do not damage the existing accessible boardwalk into the adjacent housing unit.

4. Completely remove trees designated on the attached drawings, a total of up to 5 full sized trees and 5 smaller trees (less than 8 inches in diameter at breast height) - trees which roots extend into new drainfield location. Completely remove stumps and roots up to 4 ft deep within the drainfield location and a 15 ft shoulder area around the drainfield. Only remove trees which are designated to be removed. Trees not identified in this scope of work, but which must have roots removed in order to install the new septic system shall be identified to the COR prior to removing roots. Roots from other trees which extend into the proposed location of the new septic tank, distribution box, and drainfield trenches shall be removed to 15 ft away from the new trench.

5. Remove unsuitable soil within the perimeter of the new drainfield trenches which would act as the absorption area for the new drainfield below the level of the new drain lines and which contain organic material including roots or other organics, approximately 30

cy. Dispose of roots off site. Reuse existing sandy loam soil for drainfield fill which is free of roots, leaves, and other organic material so that soil is chroma 3 or less according to the Munsell Color Charts. Reused soil shall be “Suitable” as defined by 15A NCAC

18A paragraphs .1939 - .1948 with special attention to paragraph .1941 SOIL

CHARACTERISTICS. 15A NCAC 18A is attached to this scope of work for reference.

6. Haul and place new suitable soil (approx. 30 cy) to fill the excavated roots and organic material which was removed. New soil shall be classified as Soil Group I or Soil Group

II according to 15A NCAC 18A paragraph .1941.

7. Provide new 1,000 gallon concrete septic tank. Locate new tank as shown on the attached sketch and per the approved construction submittal. Configure the new tank and drain lines to prevent clogs in drainlines and to avoid existing structures.(See below sketch of proposed layout of new tank and drainfield).

a. Provide new 4” diameter schedule 40 PVC septic hook up for VIP Site 2 at the same location as the existing, as shown on the attached drawing. New hook up shall stub up a minimum of 6 inches above ground level.

b. Provide new schedule 40 PVC 4” diameter PVC septic from the existing drainline connection FOR vip Site 1 to the new septic tank. Provide 2 cleanouts, one facing

Replace Septic Tank and Drainfield at Ft Raleigh VIP RV Pads Page 6 each direction, in the new drainline, at the junction of the connection of the existing drainline and the new drainline as shown on the attached drawing.

c. Provide properly sealed joints and connections from the existing drain pipes to new sections of pipe which seal to the new septic tank. Use PVC pipe meeting

International Plumbing Code for gravity septic drain lines, elbows, and wyes.

d. Septic wye sweeps shall meet International Building Code (Table 706.3 CHAPTER

7 SANITARY DRAINAGE, 2018 International Plumbing Code (IPC) | ICC Digital Codes

(iccsafe.org)) of for septic system installation.

8. The new 1,000 gal septic tank shall include at a minimum:

a. Water tight joints

b. Concrete baffles

c. Effluent filter

d. Access opening less than 18 inches from the end of the tank to visually see the inflow pipe.

e. Adequate opening less than 12 inches from the effluent filter to be able to visually see and physically reach the effluent filter without entering the tank.

f. Access opening to visually see the concrete baffle.

g. Provide Concrete lids on the concrete septic tank with type 316 stainless steel handles. Concrete tanks with risers do not require concrete lids with stainless handles as long as the HDPE risers and riser lids meet State requirements for lids.

h. HDPE risers and riser lids which extend a minimum of 12 inches above grade.

Riser lids shall be locking or mechanically sealed.

9. Provide new distribution tank and infiltrator chamber drainfield according to Attachment

1 and Attachment 2. Minimize the removal of roots and overall disturbance to the site to install the new septic system.

a. Drainfield shall be a minimum of 114 LF of new drain lines.

b. Install 3 drain lines at 38 ft long.

c. Drain lines shall be placed at 9 ft on center.

d. Provide 36 in wide infiltrator type septic drainfield sections similar to Infiltrator

Water Technologies Quick4 Standard 36 which provide a minimum overall length of 114 LF of infiltration drain lines. Low profile for lower capacity is not acceptable.

e. Install chambers according to manufacturer’s installation instructions. Provide filter cloth above infiltrator sections according to the manufacturer’s instructions for the brand name utilized.

10. Provide hydroseeding to the disturbed areas, including and ruts or other disturbance created by construction work. Fill ruts or low areas with suitable material. Continue to water the grass until 75% of the area has seeded and growing.

a. Seed shall be suitable for the following:

i. Mostly shade location

ii. Residential lawn

iii. Mowing operations with hand operated push or riding mowers

iv. Sandy soils

v. Septic Field coverage (roots that do not grow deeper than 24 inches) https://codes.iccsafe.org/content/IPC2018/chapter-7-sanitary-drainage https://codes.iccsafe.org/content/IPC2018/chapter-7-sanitary-drainage https://codes.iccsafe.org/content/IPC2018/chapter-7-sanitary-drainage

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vi. No weeds (dandelion, bahai, pennywort)

vii. No exotic species.

b. Hydroseed. Add a cover crop of grain rye at 30 lbs/acre. Rake broadcasted seed mix into the soil and saturate with water 2 – 3 times per day for 7 days, or until

75% of the area has seeds germinated and growing at least 1 inch high.

Hydroseeded area may be observed for 7 days or until 75% of the area has growing seeds. If after 7 days, the area is less than 75% covered with new growth, overseed again and water 2-3 times per day until 75% of the ground is covered with growth.

NOTES:

1. The Contractor must track demolition debris which are removed/recycled and provide NPS with receipts showing the weight and volume and type of material removed/recycled as part of this project.

2. No construction debris will be allowed to be left on premises. All public areas will remain clean and passible during normal business hours. During business hours, the contractor will ensure that no music is playing in the work areas and no foul language will be tolerated during or after business hours. Work on this project will be accomplished within the hours of 7:00 AM to 5:00 PM Monday thru Friday.

5.0 GOVERNMENT FURNISHED PROPERTY

1. No Government property, materials, or equipment will be provided. Water and electricity on the exterior of the existing house is available for Contractor use during this project. Contractor is responsible for lockout/tagout. Contractor is responsible for cleaning up site daily, and for repairing ruts created in grass areas. Ruts shall be filled in or raked smooth before final acceptance of the project.

6.0 SUBMITTALS

1. Work schedule: delineating the various stages of work by phase (milestones) prior to the preconstruction conference.

2. Safety Plan/Accident Prevention Plan prior to the preconstruction conference.

3. Product Data

a. Septic Tank

b. Septic Chambers

c. Connections, Fittings, Wyes, PVC pipe

d. Manhole Riser Data

e. Fill Material

f. Seed Mix

g. Operation and Maintenance Manuals

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4. Product Samples. The Contractor shall submit written documentation or color/product samples for materials identified in the Scope of Work for selection by the CO/COR.

a. Fill Material

b. Seed Mix

5. As-built drawing. Provide a to-scale surveyed drawing of the new septic system showing the accurate location of the new tank, distribution box, and drainlines. Include the locations relative to the existing fencelines, buildings, water lines, electric lines, and pavement.