B08_Attachment_1_-_Scope_of_Work.docx

DEATH VALLEY

NATIONAL PARK

Repair Landfill Cap and Drainage at Furnace Creek

PMIS NO. DEVA 337564

PROJECT SCOPE OF WORK

NATIONAL PARK SERVICE

PACIFIC WEST REGION

Revised 7/4/2024

THIS PAGE INTENTIONALLY LEFT BLANK

PMIS 337564 / Repair Landfill Cap at Furnace Creek Death Valley National Park

1.0 Overview

In late August, 2023, the Park experienced a historic flood event. This flood event severely damaged Park infrastructure. The Park has a closed landfill that is capped. There are waterbars on the cell caps that direct water into the main flow channel via culverts. These culverts cross under the dirt road into the main flow channel. The excessive stormwater created erosion channels on the cap and eroded the outlets of the existing culverts. The main flow channel shows signs of erosion and the soil on the caps of the upper two cells had the most erosion damage. Erosion channels are also present near the toe of the water bars. The purpose of this project is to restore the landfill cap by repairing the erosion damage, install larger culverts, and to armor the existing flow channels and water bars with new rip rap.

2.0 Project Location

The landfill is located near Furnace Creek at approximately the following coordinates:

Latitude: 36.470158° Longitude: -116.852185°

LOCATION OF PROJECT

Figure 1: Map showing approximate location of the landfill.

3.0 Scope of Work

RIP RAP SECTION OF THE MAIN FLOW CHANNEL

REPAIR EROSION DAMAGE IN THE MAIN DRAINAGE CHANNEL (~1,500 FT)

INSTALL NEW WATER BAR, RIP RAP, AND CULVERT

INSTALL NEW WATER BAR, RIP RAP, AND CULVERT

REPAIR WATER BAR EROSION AND INSTALL RIP RAP ON UPHILL SIDE

REPAIR WATER BAR EROSION AND INSTALL RIP RAP ON UPHILL SIDE

REMOVE AND REPLACE CULVERT AND INSTALL RIP RAP ON OUTLET SIDE

FIG. 5

HOLE #3

HOLE #2

HOLE #1

Figure 2: Site of the Furnace Creek landfill showing existing infrastructure. Orange lines indicated the existing roadway. Orange circles indicate the approximately location of the ground holes. Blue line represents the main flow channel. Cells 1,2,3,4 are approximately 250 ft in width.

1. Test existing soil cap material for soil properties:

· Employ qualified soil testing company to test the existing cap material for particle size distribution, plasticity index, and modified proctor for compaction curve.

· ASTM C136 Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates

· ASTM D1557-07 Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort

· ASTM D4318-17e1 Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils

· Take soil sample from center of Cell #2

2. Repair erosion on existing water bars:

· Water bars are approximately 250 ft in width. Erosion is approximately 1’x1’ on the uphill side of the waterbars.

· Fill erosion channels, compact, and regrade to match existing slope of waterbar.

· Install new 6”-9” angular rip rap on uphill side of the waterbar. Install rip rap for the entire length of the waterbar.

· Rip rap to extend 24” uphill of the waterbar, and 12” up the side of the waterbar

· Approximately 15 CY of soil required per waterbar

3. Repair erosion in existing main flow channel:

· Main flow channel is approximately 1500 ft in length. Erosion is approximately a 1’x1’ channel

· Fill erosion channels, compact, and regrade.

· Approximately 55 CY of soil is needed to repair the main flow channel.

4. Repair erosion on landfill caps in cells 1-5:

· Damage to be repaired is of various widths and lengths. Damage is minimal and only a few inches deep and wide per each erosion channel. There are many of these small erosion channels that need to be repaired. See Fig 3 and 4 for general example of these flow channels.

· Fill erosion channels, compact, and regrade.

5. Install two new waterbars with culverts in cells 1 and 2

· Match dimensions of existing water bars (approximately 6’ width x 2’ height)

· Install new 6”-9” angular rip rap on uphill side of the waterbar. Install rip rap for the entire length of the waterbar.

· Rip rap to extend 24” uphill of the waterbar, and 12” up the side of the waterbar

· New water bars to be placed approximately halfway between the existing water bars as shown on figure 2.

6. Remove existing culverts at ends of waterbars, and install new culverts

· Install new 10” diameter culverts. Length is approximately 25’.

· Install approximately 2 CY of 6”-9” angular rip rap on outlet sides of all culverts

· Install culverts with minimum 3% slope to outlet

· Dispose of old culvert piping

· Restore roadway to functional state

7. Fill in holes #1-3 near cell #5

· Fill and compact holes.

INSTALL NEW WATER BAR, RIP RAP, AND 10” CULVERT

REPAIR EROSION ON LANDFILL LINER (TYPICAL)

Figure 3: Cell #1 damage.

INSTALL NEW WATER BAR, RIP RAP, AND 10” CULVERT

REPAIR EROSION AT TOE OF WATER BAR AND INSTALL RIP RAP ON UPHILL SIDE OF WATERBAR

REPAIR EROSION AT TOE OF WATER BAR

FILL AND COMPACT EROSION DAMAGE (TYPICAL)

Figure 4: Cell #2 damage.

Figure 6: Main flow channel erosion looking downhill. Fill and compact erosion channel.

Figure 5: Main flow channel looking downhill near vehicle crossing.

Figure 7: Hole #1 Figure 9: Hole #3 Figure 8: Hole #2

Figure 10: Culvert outlet erosion Figure 9: (Upper) main channel erosion Figure 8: Culvert outlet erosion

4.0 Definition of Contract Line Items

Contract Line Item No. 01 – Soil Testing All soil sampling, soil testing, labor, materials, and appurtenances to complete the work as specified.

Contract Line Item No. 02 – Repair erosion on landfill cap, main channel, and water bars; install rip rap on waterbars; fill in holes 1,2,3 near Cell #5 All excavating, backfill, compaction, grading, soil, hauling, rip rap, work, labor, materials, and appurtenances to complete the work as specified.

Contract Line Item No. 03 – Install new culverts with rip rap at ends of waterbars.

All excavating, backfill, compaction, grading, soil, hauling, culvert pipe, rip rap, disposal, work, labor, materials, and appurtenances to complete the work as specified.

5.0 Technical Details

1. Contractor shall field verify and estimate the quantity of soil required to repair the erosion and communicate this quantity with NPS.

2. Compact all repairs to 90% of dry unit density per the modified proctor results.

3. Contractor to ensure liner cap is not penetrated while taking samples for the soil tests.

4. Contractor shall follow and abide by the NPS invasive species inspection requirements in Attachment 2.

5. Contractor shall follow and standard construction guidelines laid out in Attachment 1, General Specifications and Standard Construction Conditions.

6. Contractor to take and submit to NPS a minimum of 10 photos showing completed repairs of the landfill

7. Contractor to clean site after completion of project.

8. Contractor shall work with Park safety to ensure safety within the Park during construction operations.

9. Contractor to coordinate with Park for access to landfill. There is a locked gate that will require NPS staff to open.

6.0 Submittals

Contractor to provide the following submittals to NPS for review and approval:

a. Soil Test results:

i. Information on the proposed qualified testing firm, contact information, location.

ii. ASTM C136 Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates

iii. ASTM D1557-07 Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort

iv. ASTM D4318-17e1 Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils

b. Backfill soil

i. Submit cap soil material based on results from ASTM C136 Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates and ASTM D1557-07 Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort and ASTM D4318.

ii. Name and location of source pit, point of contact at source pit, sieve and proctor analysis on proposed soil backfill material.

iii. Plasticity index of proposed soil backfill material (if available).

iv. Free of deleterious and organic material

v. Free of rocks, stones, and gravel

c. Culvert Pipe

i. Smoothbore HDPE, SDR 11

ii. 10” Diameter

d. Rip Rap

i. Name and location of source pit, point of contact at source pit

ii. 6”-9” angular rip rap

iii. Free of deleterious and organic material

iv. Round, smooth, or “river” rock will be rejected

7.0 Attachments

1. DEVA General Specifications and Standard Construction Conditions

2. SOP - Invasive Species - Death Valley 2020 image1.wmf image2.png image3.emf image30.emf image4.png image5.jpeg image6.jpeg image7.jpeg image8.jpeg image9.jpeg image10.jpeg image11.jpeg image12.jpeg image13.jpeg