SOW__Replace_Septic_System_at_Quarters_1441_6_pages.pdf

Replace Septic Tank and Drainfield at Ft Raleigh Quarters 1441 Page 1

CAPE HATTERAS NATIONAL SEASHORE

Fort Raleigh

Manteo, North Carolina

STATEMENT OF WORK:

Replace Septic Tank and Drainfield at Ft Raleigh Quarters 1441

NATIONAL PARK SERVICE

Region 2

Replace Septic Tank and Drainfield at Ft Raleigh Quarters 1441 Page 2

CAPE HATTERAS NATIONAL SEASHORE

Outer Banks Group

Statement of Work

Replace Septic Tank and Drainfield at Ft Raleigh Quarters 1441

1.0 INTRODUCTION

The National Park Service (NPS) Cape Hatteras National Seashore (CAHA) has a requirement to replace the septic tank and drainfield at Quarters 1441 on Fort Raleigh National Historic Site

(FORA).

2.0 CONSTRUCTION SITE LOCATION

The address for the project site is 1441 Pear Pad Rd Manteo, NC 29754.

3.0 BACKGROUND AND EXISTING CONDITIONS

The quarters at 1441 Pear Pad Rd in Manteo, NC is a 3 bedroom, single family house. The existing wastewater system consists of a tank approximately 750 gal and drainfield measuring approximately 40 ft wide and 70 ft long. The tank is located approx. 50 ft from the house. The drain line between the house and the tank is expected to be cast iron pipe. The drainfield in a traditional gravity system with gravel trench and perforated plastic pipe. The system is past its useful life, does not properly drain, and has been encroached by tree and other vegetation roots.

Sewage is being pumped periodically from the septic tank to allow limited usage of the quarters.

The water service for the house is on the east side near Pear Pad Rd. The electrical service for the house is located on the west side behind the house and is buried below ground. The electrical distribution and service to the house are within the project site.

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 (15A NCAC 18A). Specifically, the topography, landscape, soil characteristics, 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 Loan. A percolation test was not conducted on site due to the sandy nature of the soil. A maximum Long Term Acceptance

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

Replace Septic Tank and Drainfield at Ft Raleigh Quarters 1441 Page 3

Figure 1: Existing drainfield and septic tank located behind the house at 1441 Pear Pad Rd.

4.0 SCOPE OF WORK

Replace the septic system with a new septic system meeting 15A NCAC 18A.

1. Locate and mark existing utilities including at a minimum:

a. Electrical

b. Communications

c. Septic

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

a. Existing drainfield shall be abandoned in place.

b. Cut and remove the existing drain line from the house to the septic tank approximately 25 ft from the house (see Figure 2 below).

3. Completely remove one existing tree which has roots extending into the new drainfield location.

4. Install construction fence around the project site and tree protection fence around existing trees within the project area which are to remain after work is complete. Tree protection fence shall be installed at the drip line of the branches.

5. Provide new 1,000 gallon concrete septic tank. Locate new tank approximately 25 ft from the house. (See below sketch of proposed layout of new drainfield).

a. Connect the existing drain line from the house to the new septic tank with waterproof connection.

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b. Provide properly sealed joints and connections from the existing drain pipes to new sections of pipe which seal to the new septic tank. Use schedule 40 PVC or approved equal material.

6. The new 1,000 gal septic tank 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.

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

Riser lids shall be locking or mechanically sealed.

7. Provide new distribution tank and infiltrator drainfield. Drainfield shall be a minimum of

150 LF of new drain lines.

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

Water Technologies Quick4 Equalizer 36 which provide a minimum overall length of 150 LF of infiltration drain lines. Low profile or Standard profile for lower capacity is not acceptable.

b. 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.

8. Provide seeding to the disturbed area, including demolished drainfield, new drainfield, and ruts or other disturbance created by construction. Continue to water the grass until

75% of the area has seeded and growing.

i. Seed shall be suitable for the following:

1. Mostly shade location

2. Residential lawn

3. Mowing operations with hand operated push or riding mowers

4. Sandy soils

5. Septic Field coverage (roots that do not grow deeper than 24 inches)

6. No weeds (dandelion, bahai, pennywort)

7. No exotic species.

ii. Broadcast or 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.

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Figure 2: Proposed work at Q1441 Pear Pad Rd on Ft Raleigh

NOTES:

1. The Contractor is responsible for marking utilities in the vicinity of the project site.

2. 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.

3. 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

Replace Septic Tank and Drainfield at Ft Raleigh Quarters 1441 Page 6 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 Samples. The Contractor shall submit written documentation or color/product samples for materials identified in the Scope of Work.

3.1 Septic Tank product data

3.2 Septic Drain Field Infiltrator product data

3.3 Manhole/Riser data

3.4 Seed Mix