A3_EECA_Report_FINAL.pdf

Department of the Interior National Park Service

Sequoia and Kings Canyon National Parks Three Rivers, California

Final Engineering Evaluation/Cost Analysis Report Lower Kaweah Dump Area (SWMU #11)

Sequoia and Kings Canyon National Parks Tulare County, California

March 13, 2015

Prepared by:

Rafael Macedo Project Engineer II

Holly A. Trejo, PG Senior Project Manager

March 13, 2015 March 13, 2015

Engineering Evaluation/Cost Analysis Report SEKI - Lower Kaweah SWMU #11 March 13, 2015

TABLE OF CONTENTS

Page

ACRONYMS AND ABBREVIATIONS ........................................................................... vi EXECUTIVE SUMMARY ................................................................................................. I

1.0 INTRODUCTION

1.1 AUTHORITY

1.2 PURPOSE AND OBJECTIVES

1.3 BACKGROUND/SITE HISTORY

2.0 SITE CHARACTERIZATION

2.1 SITE DESCRIPTION

2.1.1 Geology and Geohydrology

2.1.2 Climate, Vegetation and Wildlife

2.1.3 Land Uses

2.2 SITE HISTORY

2.2.1 Dump Area Operational History

2.3 SUMMARY OF PREVIOUS INVESTIGATIONS

2.4 2014 EE/CA FIELD INVESTIGATIONS

2.4.1 Site-Specific Background Data

2.5 NATURE AND EXTENT OF CONTAMINATION

2.5.1 Constituents of Potential Concern

2.6 STREAMLINED RISK EVALUATION

2.6.1 Preliminary Exposure Pathways

2.6.2 Human Risk Screening Criteria

2.6.3 Ecological Risk Screening Criteria

2.6.4 Site Specific Screening Level

2.6.5 Contaminants of Concern for Removal Action

2.6.6 Risk Summary

3.0 REMOVAL ACTION OBJECTIVES & APPLICABLE OR RELEVANT AND

APPROPRIATE REQUIREMENTS

3.1 REMOVAL ACTION OBJECTIVES

3.2 REMOVAL ACTION JUSTIFICATION

3.3 IDENTIFICATION OF APPLICABLE OR RELEVANT AND APPROPRIATE

REQUIREMENTS

3.3.1 Chemical-Specific ARARs

3.3.2 Location-Specific ARARs

3.3.3 Action-Specific ARARs

4.0 IDENTIFICATION AND SCREENING OF REMOVAL ACTION ALTERNATIVES35

4.1 IDENTIFICATION OF REMOVAL ACTION TECHNOLOGIES

4.2 SCREENING OF REMOVAL ACTION TECHNOLOGIES

4.3 ASSEMBLY OF REMOVAL ACTION ALTERNATIVES

5.0 EVALUATION OF REMOVAL ACTION ALTERNATIVES

5.1 ALTERNATIVE 1: NO ACTION

5.1.1 Effectiveness of Alternative 1

5.1.2 Implementability of Alternative 1

5.1.3 Cost of Alternative 1

ii

5.2 ALTERNATIVE 2: CAPPING, RE-VEGETATION AND INSTITUTIONAL CONTROLS43

5.2.1 Effectiveness of Alternative 2

5.2.2 Implementability of Alternative 2

5.2.3 Cost of Alternative 2

5.3 ALTERNATIVE 3: CAPPING, PHYTOREMEDIATION AND INSTITUTIONAL

CONTROLS

5.3.1 Effectiveness of Alternative 3

5.3.2 Implementability of Alternative 3

5.3.3 Cost of Alternative 3

5.4 ALTERNATIVE 4: EXCAVATION AND OFF-SITE DISPOSAL

5.4.1 Effectiveness of Alternative 4

5.4.2 Implementability of Alternative 4

5.4.3 Cost of Alternative 4

5.5 COMPARATIVE ANALYSIS OF REMOVAL ACTION ALTERNATIVES

6.0 CONCLUSIONS AND RECOMMENDATIONS

6.1 RECOMMENDED REMOVAL ACTION ALTERNATIVE

6.2 REMOVAL SCHEDULE

6.3 PUBLIC COMMENT

FIGURES

Figure 1.1: Site Location Map Figure 2.1: Site Features Figure 2.2: Site Layout Map Figure 2.3: Trench and Sample Locations Figure 2.4: ISM Sample Locations Figure 2.5: Trench T1 Cross-Section and Plan View Figure 2.6: Trench T2 Cross-Section and Plan View Figure 2.7: Trench T3 Cross-Section and Plan View Figure 2.8: Trench T4 Cross-Section and Plan View Figure 2.9: Trench T5 Cross-Section and Plan View Figure 2.10: Trench T6 Cross-Section and Plan View Figure 2.11: Human Exposure Conceptual Site Model Figure 2.12: Ecological Exposure Conceptual Site Model Figure 4.1: Schematic Cap Design

EMBEDDED TABLES

Table 3.1: Removal Action Justification Table 3.2: Chemical-Specific ARARs Table 3.3: Location-Specific ARARs Table 3.4: Action-Specific ARARs Table 4.1: Removal Action Technologies Table 4.2: Removal Action Technology Screening Table 5.1: Comparative Analysis of Removal Action Alternatives

ATTACHMENTS

Attachment A Approval Memorandum iii

Attachment B Laboratory Analytical Result Tables, Reports and Chain-of-Custody

Documentation Table B-1: Decision Unit Sample Results and Estimated Background Concentrations Table B-2: Laboratory Analytical Results - Metals Table B-3: Laboratory Analytical Results - Total Petroleum Hydrocarbons and Semi-Volatile Compounds Table B-4: Laboratory Analytical Results – Polychlorinated Biphenyls, Dioxins and Furans Table B-5: Laboratory Analytical Results – Organochlorine Pesticides and Herbicides Table B-6: Laboratory Analytical Results – Phytoremediation / Agricultural Parameters Table B-7: Laboratory Analytical Results – Background, Waste Stream and Adjacent Native Soils 95% UCL Comparison

Attachment C Screening Level Ecological Risk Assessment Calculation Tables Table C-1: Habitat Type and Species Inventory Table C-2: ISM Calculator for 1-sided UCL for the Mean Table C-3: ARAR Soil Screening Levels Table C-4: Site Specific Screen Level Calculation Table C-5: Hazard Quotient Calculation Table C-6: Area Use Factor Calculations

Attachment D Cost Estimates Table D-1: Design Alternatives Cost Comparison Summary Table D-2: Alternative 2 - Capping, Re-vegetation and Institutional Controls Table D-3: Alternative 3 - Capping, Phytoremediation and Institutional Controls Table D-4: Alternative 4 - Excavation, Transportation and Off-site Disposal

Attachment E Photo Log Attachment F Responsiveness Summary iv

This page intentionally left blank.

v

ACRONYMS AND ABBREVIATIONS

amsl above mean sea level ARAR Applicable or Relevant and Appropriate Requirement AUF Area Use Factor bgs below ground surface CAMU Corrective Action Management Unit CCR California Code of Regulations CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CESA California Endangered Species Act CFR Code of Federal Regulations COC contaminant of concern COPC constituent of potential concern CSM conceptual site model cy cubic yard DDE dichlorodiphenyldichloro-ethylene DDT dichlorodiphenyltrichloroethane DTSC Department of Toxic Substances Control DRO Diesel range organics DU decision unit ECM Environmental Cost Management, Inc.

ED exposure dose EE/CA Engineering Evaluation/Cost Analysis EPA United States Environmental Protection Agency EPC exposure point concentration °F Degrees Fahrenheit GPS global positioning system HERA Human Health and Ecological Risk Evaluation HI Hazard Index HQ Hazard Quotient IC Institutional Control ISM Incremental Sampling Methodology kg kilogram MCL maximum contaminant levels mg/kg milligrams per kilogram mg/L milligrams per liter MI multi-increment NCP National Oil and Hazardous Substance Pollution Contingency Plan NPS National Park Service NTCRA non-time critical removal action vi

OM&M operation, maintenance, and monitoring PA Preliminary Assessment PCB Polychlorinated Biphenyl pg/g picograms per gram PRG Preliminary Remediation Goal QA quality assurance QAPP Quality Assurance Project Plan QC quality control RAO Removal Action Objectives RCRA Resource Conservation and Recovery Act RSL Regional Screening Level RSV risk screening value RWQCB Regional Water Quality Control Board SA site assessment SEKI Sequoia and Kings Canyon National Parks SI site investigation sq ft square feet SRE streamlined risk evaluation SSSL site specific screening level STLC soluble threshold limits concentrations SVOC semivolatile organic compound SWMU Solid Waste Management Unit TCLP toxicity characteristic leaching procedure TRV Toxicity Reference Value TTLC Total Threshold Limit Concentrations UCL upper confidence limit U.S.C. United States Code VOC volatile organic compound vii

EXECUTIVE SUMMARY

The Department of Interior, National Park Service (NPS) retained Environmental Cost Management, Inc. (ECM) to prepare an Engineering Evaluation/Cost Analysis (EE/CA) Report for the Lower Kaweah Dump Area, Solid Waste Management Unit (SWMU) #11 at Sequoia and Kings Canyon National Parks (SEKI) in Tulare County, California (Figure 1.1). NPS is engaging in a non-time critical removal action (NTCRA) process at SEKI, using their authority under the Comprehensive Environmental Response, Compensation, and Liability Act

(CERCLA).

NPS identified an old dumpsite during inspections of the Lower Kaweah area within the Giant Forest at Sequoia National Park. In 19981 and 20012, two site investigations reported that materials present on the surface of the dump pile consisted of wood, concrete, asphalt fragments, and other debris. The contents of the dump fill consisted mostly of burn materials.

Some of the observed fill materials consisted of ash, metal, glass, sheet metal, porcelain, aluminum pans and pitchers, wire, pipes, metal paint cans, wood chips and roots. No water was observed atop the bedrock surface below the dump fill material.

A Human Health and Ecological Risk Evaluation3 (HERA) for the Site concluded that no unacceptable human or ecological effects from site contaminants were expected to occur. In the HERA it is reported that the Site is covered with a clean soil/gravel cover material, 1 to 2 feet thick. Documentation for the design and dates of placement of this cover material do not exist, but correspondence between NPS and Department of Toxic Substances Control (DTSC) indicate that this cover was placed during the year 2000 or 2001 with apparent DTSC approval.

The 1998 and 2001, Site Investigation (SI) and expanded Site Assessment (SA), respectively, indicated that CERCLA hazardous substances were present at elevated concentrations in materials and soils in the dump area. Because the exact locations of samples collected during both investigations are not clearly identified, and composite samples were collected mixing suspected clean soil with impacted soil, the extent of contamination was not clearly defined.

This represents a gap in the Site characterization. Although the HERA concluded no human or ecological exposure risk exits, NPS reviewed all available Site information and concluded that the SI and expanded SA did not completely characterize the nature and extent of contamination for purposes of conducting a NTCRA. To address these gaps in the characterization of contamination, NPS directed ECM to prepare and perform a Work Plan4 to address the remaining data needs for a complete Site characterization and the preparation of this EE/CA Report.

1 Kleinfelder, 1998.

2 Kleinfelder, 2002.

3 U.S. Army Corps of Engineers, 2005.

4 Environmental Cost Management, Inc. (ECM), 2014. Work Plan for Additional Soil Assessment, Sequoia and

Kings Canyon National Parks, Three Rivers, CA. March 6.

I

Using the additional collected data, ECM completed a streamlined risk evaluation (Section 2.6) for human and ecological receptors that indicates hazard indices above one, for both ecological and human receptors, which indicate that leaving the impacted soil and waste materials associated with the Lower Kaweah Dump Area in its present condition, could pose an unacceptable risk to human health and the environment.

The scope of removal action evaluated in this EE/CA Report focuses on the following removal action objectives (RAO):

• Prevent or reduce the potential for human and ecological exposure (through inhalation, ingestion, and dermal contact) to contaminants of concern (COCs) in soil.

• Prevent or reduce potential migration of impacts via surface runoff, erosion, and wind dispersion.

Four removal action technologies were reviewed (Section 4) to develop the following four removal action alternatives:

• Alternative 1 – No Action

• Alternative 2 – Capping, Re-vegetation and Institutional Controls

• Alternative 3 – Capping, Phytoremediation and Institutional Controls

• Alternative 4 – Excavation and Off-Site Disposal

The four removal action alternatives were evaluated based on the following overall criteria:

1) Effectiveness

a) Protectiveness

b) Level of treatment and/or containment

c) Reduction or elimination of contaminants of concern

2) Implementability

a) Technical feasibility

b) Administrative and legal feasibility

c) Ease of Implementation

3) Cost

a) Capital cost

b) Post removal site controls cost

c) Present worth value / present cost

d) Long-term operation, maintenance and monitoring (OM&M) costs

Effectiveness and implementability have been evaluated in detail in subsections presented for each alternative in Section 5.

Based on the information presented in this EE/CA Report and previous investigations, it is recommended to implement Alternative 4, consisting of Excavation and Off-Site Disposal.

II

Alternative 4 is the most protective of human health and ecological resources and it will eliminate the potential for environmental impacts, in the short- and long-term, immediately after completion, meeting all the evaluation criteria. There are no post-removal OM&M activities associated with the implementation of Alternative 4.

III

This page intentionally left blank.

IV

1.0 INTRODUCTION

On behalf of the Department of the Interior, National Park Service (NPS), Environmental Cost Management, Inc. (ECM) prepared this Engineering Evaluation/Cost Analysis (EE/CA) Report for the Sequoia and Kings Canyon National Parks (SEKI) in Three Rivers, California (Figure 1.1). This EE/CA Report addresses the Lower Kaweah Dump Area, referred herein as “the Site”, because of elevated concentrations of contaminants found in soil during previous and recent investigations.

1.1 AUTHORITY

This EE/CA Report has been prepared in accordance with the criteria established under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as well as sections of the National Oil and Hazardous Substances Pollution Contingency Plan (NCP) as applicable to removal actions (40 Code of Federal Regulations [CFR] §300.415 [b][4][I]). NPS has been delegated CERCLA lead agency authority by the President of the United States and the Secretary of the Interior, and is exercising this authority at the Site. This EE/CA is consistent with the United States Environmental Protection Agency (EPA) Guidance on Conducting Non-Time-Critical Removal Actions under CERCLA, EPA/540-R-93-057, Publication 9360.0.32, PB93-963402, August 1993.

1.2 PURPOSE AND OBJECTIVES

This EE/CA provides an engineering evaluation to support the selection of a Non-Time-Critical Removal Action (NTCRA) for the Site. Environmental investigations at the Site have identified conditions that correspond to factors in Section 300.415(b)(2) of NCP (40 C.F.R. 300.415).

These conditions indicate that an NTCRA may be necessary to abate, prevent, minimize, stabilize, mitigate, or eliminate threats to human health and the environment.

National Oil and Hazardous Substance Pollution Contingency Plan (NCP) discusses three types of removal actions: emergency, time critical, and non-time-critical. These designations are based on the urgency with which cleanup must be initiated to respond to a threat to human health and the environment posed by a release or potential release of hazardous substances.

Emergency and time-critical removal actions are initiated to respond to a release or potential release where less than six months are available for planning the response. An NTCRA may be implemented at SEKI Lower Kaweah Dump Site, because the Site Investigation5, Site Assessment6 and Risk Assessment7 indicated that no immediate threat to human health or the

5 Kleinfelder, Inc. Site Investigation Report, Giant Forest – Lower Kaweah Dump Area. Sequoia National Park, California. November 25, 1998.

6 Kleinfelder, Inc. Lower Kaweah Dump Area, Expanded Site Assessment. Sequoia National Park, California.

January 11, 2002.

7 US Army Corps of Engineers. Sacramento District, Environmental Design Section, Human Health and Ecological Risk Evaluation Lower Kaweah Dump Area, Sequoia National Park, California, Draft, August 2005.

environment exists at the Site, therefore NPS determined that more than six months are available for planning a response for the identified source of contaminants.

An Approval Memorandum (Attachment A) authorized the preparation of this EE/CA Report.

The Approval Memorandum is the first step in NTCRA process. Section 300.415(b)(4)(I) of NCP requires the development of an EE/CA Report with a public comment period, prior to the signing of the Action Memorandum to initiate the selected alternative for NTCRA.

The EE/CA Report identifies removal action objectives for protection of human health and the environment, identifies removal action alternatives, and assesses the effectiveness, implementability, and cost of the alternatives that satisfy the removal action objectives.

The EE/CA Report considers the nature of the contamination, any potential risks to human health and the environment, and how the alternatives fit into the strategy for Site remediation.

The goals of the EE/CA Report include:

• Conduct a Streamlined Risk Evaluation (SRE) to determine the potential threats posed by contamination originating from the Site;

• Prepare a list of remedial technologies, screen the remedial for Site specific goals assemble selected technologies into proposed removal action alternatives and propose a removal action alternative to address contamination;

• Provide a framework for the evaluation and selection of potential response actions and applicable technologies consistent with the NCP and EPA Guidance.

1.3 BACKGROUND/SITE HISTORY

NPS identified an old dumpsite during inspections of the Lower Kaweah area within the Giant Forest at Sequoia National Park. The specific contents of the suspected dumpsite were undocumented and unknown, but thought to include burn ash from the former Lower Kaweah incinerator. In 19988 and 20019, two site investigations indicated that materials present on the surface of the dump pile consisted of wood, concrete, asphalt fragments, and other debris. The contents of the dump fill consisted mostly of burn materials. Some of the observed fill materials consisted of ash, metal, glass, sheet metal, porcelain, aluminum pans and pitchers, wire, pipes, metal paint cans, wood chips and roots. No water was observed atop the bedrock surface below the dump fill material.

A Human Health and Ecological Risk Evaluation10 (HERA) for the Site concluded that no unacceptable human or ecological effects from site contaminants were expected to occur. In the HERA it is reported that the Site is covered with a clean soil/gravel cover material, 1 to 2 feet thick. Documentation for the design and dates of placement of this cover material do not exist, but correspondence between NPS and DTSC indicate that this cover was placed during the year 2000 or 2001 with apparent DTSC approval. According the HERA report, as a result of

8 Kleinfelder, 1998.

9 Kleinfelder, 2002.

10 U.S. Army Corps of Engineers, 2005.

this cover material, direct exposure to the contaminated soil/debris is not likely to occur. In the HERA report it is assumed that potential receptors could come in direct contact with the contaminated soil and debris, as if no cover was present at any portion of the dump area, theoretically overestimating the risk for actual receptors. However, the HERA used data from the existing Site Investigation11 and Site Assessment12, which may not have captured representative concentrations due to composite soil sampling mixing from suspected clean areas with impacted areas. Finally, background concentrations had not been established for the Site.

After reviewing the entire presented Site information, NPS concluded that the Site Investigation and Site Assessment performed did not completely characterize the nature and extent of contamination at the Site and that the conclusions and recommendation in the HERA report could not be applied. ECM reviewed the data from these reports and performed additional site assessment activities to facilitate the completion of this EE/CA Report.

11 Kleinfelder, 1998.

12 Kleinfelder, 2002.

2.0 SITE CHARACTERIZATION

This section gives a general site description and an overview of site investigations that have been completed to characterize the nature and extent of impacts to soil at the Site.

2.1 SITE DESCRIPTION

The Site is located near a maintenance yard, at approximately 1,350 feet northwest of the Giant Forest Museum, located at the intersection of Generals Highway and Crescent Meadow Road in the Lower Kaweah area of the Giant Forest in SEKI (Figure 2.1). The Site covers an approximate 11,500-square-foot area of non-symmetrical shape (approximately an oval shape) at an elevation of approximately 6,400 feet above mean sea level (amsl). The dump area is mainly level and gently slopes (approximately 0.13 ft/ft) to the southwest. The thickness of the dump fill material ranges from 2 to 9 feet, with an estimated average thickness of 5 feet. A mixed-conifer forest surrounds the area with topography sloping gently to the southwest (approximately 0.17 ft/ft). Numerous large downed pine trees cross portions of the Site and the general vicinity. A large granite slab (bedrock) exists on the north side of the adjacent trail road, and slopes towards the dump (Figure 2.2).

2.1.1 Geology and Geohydrology

The Site is located in an area of near-surface granitic bedrock, which is characteristic of the upper elevations of the Sierra Nevada Mountains. Soil accumulations are generally granular in nature and relatively thin. Groundwater in this environment is usually present in localized fractures in the bedrock or not at all. No surface water or shallow groundwater was encountered above the bedrock in the area of the Site during previous explorations. However, during periods of heavy rain or snowmelt in the spring, the ground may become saturated in localized areas.

Geology/Geologic History13 SEKI is the home of prominent and renowned geological features and resources. The parks contain a significant portion of America's longest mountain range, the Sierra Nevada. Included in the Parks' mountainous landscape is the tallest mountain in the contiguous United States, Mt.

Whitney, which rises to 14,491 feet above sea level. Eleven additional peaks taller than 14,000 feet are also found along the parks' eastern boundaries at the crest of the Sierra Nevada.

In Kings Canyon National Park, prominent ridges extend westward from the crest creating the Goddard and Monarch divides with mountains taller than 13,000 feet. In Sequoia National Park, a second prominent ridge of mountains, The Great Western Divide, parallels the Sierran crest.

These mountains of the Great Western Divide are visible in Mineral King and from Moro Rock and the Giant Forest area. Peaks in the Great Western Divide climb to more than 12,000 feet.

13 National Parks Service. Sequoia and Kings Canyon, Geology Overview. http://www.nps.gov/seki/naturescience/ geology_overview.htm.

Between these mountains lie deep, spectacular canyons. The most significant is Kings Canyon.

In the parks, Kings Canyon is a wide glacial valley featuring tall cliffs, a meandering river, meadows, and waterfalls. A few miles outside the parks, Kings Canyon deepens and steepens becoming arguably the deepest canyon in North America for short distance. The confluence of the South Fork and Middle forks of the Kings River lies at 2,260 feet, while towering above the rivers on the north side of the canyon is Spanish Peak, which is 10,051 feet tall. The south side of this canyon above the confluence is significantly lower. Dozens of other canyons include Tokopah Valley above Lodgepole, Deep Canyon on the Marble Fork of the Kaweah River, and, deep in the parks' remote backcountry, Kern Canyon, which is more than 5,000 feet deep for 30 miles. The parks are headwaters for the Kaweah River, the Kern River, two forks of the Kings River and small areas of the San Joaquin and Tule river watersheds.

Most of the mountains and canyons in the Sierra Nevada are formed in granitic rocks. These rocks, such as granite, diorite and monzonite, formed when molten rock cooled far beneath the surface of the earth. The molten rock was a by-product of a geologic process known as subduction. Plate tectonics forced the landmass under the waters of the Pacific Ocean beneath and below an advancing North American Continent. Super-hot water driven from the subjecting ocean floor migrated upward and melted rock as it went. This process took place during the Cretaceous Period 100 million years ago. Granitic rocks have speckled salt and pepper appearance because they contain various minerals including quartz, feldspars and micas.

While geologists debate the details, it is clear that the Sierra Nevada is a young mountain range, probably not more than 10 million years old. Incredible forces in the earth, probably associated with the development of the Great Basin, forced the mountains upwards. During the 10 million years, at least four periods of glacial advance have coated the mountains in a thick mantle of ice. Glaciers form and develop during long periods of cool and wet weather. Today, a few small glaciers remain in the parks. They are the southern-most glaciers in North America.

Glaciers move through the mountains like slow-motion rivers carving deep valleys and craggy peaks. The extensive history of glaciation within the range and the erosion resistant nature of the granitic rocks that make up most of the Sierra Nevada have together created a landscape of hanging valleys, towering waterfalls, craggy peaks, alpine lakes and large glacial canyons.

The Sierra Nevada is still growing today. In fits and leaps the mountains gain height during earthquakes on the east side of the range near Bishop and Lone Pine. Rain and winter snows combined with a steep landscape induce massive movements of sediment and rapid erosion.

The mountains are being removed by erosion almost as quickly as they grow. This erosion has created and deposited sediments thousands of feet thick on the floor of the San Joaquin and Sacramento Valleys.

Small sections of the park contain areas of metamorphic rocks. These rocks are the remnants of volcanic islands that were added to North America before the Sierra Nevada uplift.

They include metamorphosed volcanic rocks, schist, quartzite, phyllite, and marble.

Hydrology14 SEKI contains some 3,200 lakes and ponds and approximately 2,600 miles of rivers and streams. Three major rivers originate in these parks --Kings, Kaweah and Kern. These rivers provide valuable irrigation water to agricultural lands in Fresno, Kern and Tulare counties as well as water for recreation and industrial activities outside the parks. The monitoring and maintenance of watershed health is clearly of interest not only to park managers but also to water users throughout this region.

Winter snowpack in the Sierra Nevada is a natural storage system for the precipitation that accumulates during winter months. The amount of water stored as snowpack increases through mid-April at higher elevations. Melt off typically begins in April and continues through May or June. October is the month in which the least water runoff occurs from park watersheds.

Snowfields, forests, lakes and streams collect, store, and release the water supplied from winter storms, so it is available throughout the dry summers for agriculture, recreation, electrical power generation and other uses. The amount of snowpack is also important to park vegetation and wildlife. In years of low snowpack accumulation, less water is available for plant growth (for example, many trees will produce a small annual ring in years of drought). During these drought years, reduced plant growth and fruit and seed production result in altered food production for wildlife.

Water determines the distribution and abundance of many plants and animals throughout the Sierra Nevada by shaping and providing habitat. Lakes and streams support rich communities of native organisms both in the water and in adjoining riparian areas. Water is also a powerful attractant to human visitors to these parks, as is evident from the popularity of rivers, streams and lakes as destinations for picnickers, hikers, campers and anglers. Introduced (non-native) animals, human use of rivers and lakes, runoff and effluent from park developed areas and ecosystem-level, human-caused changes have had negative impacts on SEKI water resources.

Park research, inventory and monitoring are critical in identifying changes in water quality and quantity and declines in native plant and animal populations that can result from human-caused impacts to aquatic systems.

2.1.2 Climate, Vegetation and Wildlife

Climate At middle elevations (approximately 4,000 to 7,000 feet amsl) in this forested area of the parks, summer offers warm days and cool evenings. These elevations receive an average of 40 to 45 inches of precipitation annually. Much of this falls during the winter, resulting in a deep blanket of snow from December to May. Temperatures below zero degrees Fahrenheit (°F), however, are rare. In the summer, occasional afternoon thundershowers may occur. Temperatures in mid-summer may reach 90 °F.

14 National Parks Service. Sequoia and Kings Canyon, Water Resources Overview. http://www.nps.gov/seki/ naturescience/water.htm.

Vegetation Extreme topographic differences and a striking elevation gradient (ranging from 1,360 feet in the foothills to 14,494 feet along the Sierran crest) create a variety of environments, from the hot, dry lowlands along the western boundary to the stark and snow-covered alpine high country.

Topographic diversity supports over 1,200 species (and more than 1,550 taxa, including subspecies and varieties) of vascular plants, which make up dozens of unique plant communities. These include not only the renowned groves of massive giant sequoia, but also vast tracts of montane forests, alpine habitats, and oak woodlands and chaparral. The Sierran flora mirrors that of the state as a whole; over 20 percent of Californian plant species can be found within SEKI15.

Unlike many of the cone-bearing, evergreen forests of the world, which are dominated by a single species of tree, the mixed-conifer forests that cloak the lower and middle slopes of the Sierra Nevada are remarkably diverse. Here ponderosa pine, incense cedar, white fir, sugar pine, and scattered groves of giant sequoia intermix and coexist. These trees, many of which reach tremendous heights, form some of the most extensive stands of old-growth coniferous forest that remain in the world.

In the upper montane, pure stands of red fir and lodgepole pine are predominant.

Characterized by deep snow accumulation during the winter months and a dense canopy that limits the amount of sunlight that reaches the forest floor, the red fir forests lack a diverse herbaceous component. Only the most shade tolerant herbs thrive beneath the towering trees.

Lodgepole pines have an unusual distribution, growing in both moist lowlands and in drier sites on benches and ridges. In wetter sites, these forests can support a rich amalgam of herbs and wildflowers in their understory16.

Wildlife SEKI supports a wide diversity of animal species, reflecting their range in elevation, climate, and habitat variety. Over 260 native vertebrate species are in the parks; numerous additional species may be present but have not been confirmed. Of the native vertebrates, five species are extirpated (extinct at the parks), and over 150 are rare or uncommon.

There have been some studies of invertebrates, but not enough information is available to know how many species occur in the parks. Many of the parks' caves contain invertebrates, some of which occur only in one cave and are known nowhere else in the world.

15 National Park Service, “Sequoia and Kings Canyon Nature and Science”, retrieved on 12/17/2013 from http://www.nps.gov/seki/naturescience/index.htm.

16 Ibid.

Year-round and seasonal residents include the mammals and a variety of birds. Reptiles are not as common, but the mountain king snake, rubber boa, western fence lizard, and alligator lizard are occasionally seen17.

Mammals A total of 77 mammal species are known to occur in SEKI. An additional 13 species, such as the wolverine, Sierra Nevada red fox, and black-tailed hare, may also be present but exist in such low densities that their status is unconfirmed. Commonly observed species include yellow-bellied marmots, mule deer, pika, and several species of squirrels. Examples include ringtails, spotted skunks, short-tailed weasels, and mountain lions.

A diversity of habitat types is present in the parks. Two orders of mammals are particularly diverse—Rodentia (rodents) and Chiroptera (bats). There are 26 species of rodents, ranging in size from the tiny montane vole up to the beaver, which can be 4 feet long and weigh over 60 pounds. There are 17 species of bats, including several species of concern such as the Townsend's big-eared bat, pallid bat, spotted bat, Western mastiff bat, and Western red bat.

Threatened mammal species within SEKI include Sierra Nevada bighorn sheep, which were granted protection under the Endangered Species Act in 1999. This species is still threatened by the risk of disease from domestic sheep, predation by mountain lions, forest succession, genetic diversity, severe weather, climate change, and reduced geographic distribution.

The Pacific fisher, a secretive forest-dwelling carnivore, is another species with special status.

It is a candidate for listing under the Endangered Species Act and considered a Species of Special Concern by the state of California. Because fishers appear to require habitats that are prone to catastrophic wildfires (e.g., dense canopies, abundant woody debris), ongoing research throughout the region is assessing the impacts of fuel reduction treatments on fishers18.

Birds SEKI's 863,741 acres provide habitat for over 200 species of birds, including many neotropical migrants. Park biologists monitor birds to obtain more information about individual species. As known indicator species, avian monitoring also provides evidence of local and regional change for the larger ecosystem. A variety of migratory and resident birds exist at SEKI including the western tanager, violet-green swallow, white-throated swift, Wilson's warbler, olive-sided flycatcher, hermit thrush, western bluebird, and pileated woodpecker.

Amphibian, Fish and Reptile Amphibians, reptiles, and fish are found at all elevations within SEKI, and certain species may be found at all times of the year. Their occurrence ranges from common (e.g., western fence

17 National Park Service, “Sequoia and Kings Canyon Nature and Science”, retrieved on 12/17/2013 from http://www.nps.gov/seki/naturescience/index.htm.

18 Ibid.

lizards) to extirpated (locally extinct) (e.g., foothill yellow-legged frogs). The parks also have numerous species of exotics such as the bullfrog and many species of fish, which were brought into naturally fishless lakes to make the area more attractive to anglers.

The introduction of fish has had many unintended effects, the most dramatic being the resulting decline in the mountain yellow-legged frog populations which are under consideration for listing as federally endangered, due to predation. Scientists have investigated the role of other causative factors in their decline, such as acid deposition, UVB radiation, and disease, but predation is clearly the main problem. When fish are present, they eat frogs, force frogs into marginal habitat, and fragment the population, the latter of which hinders colonization. Wildlife management staff plans to remove exotic fish from some naturally fishless lakes to help restore the native frog population19.

2.1.3 Land Uses

SEKI hosted 1,697,617 visitors in 2012, with an average of 1,620,445 visitors annually from 2009 to 201220. Recreational activities vary with each season and include day hiking, backpacking, horseback riding, stock use, rock climbing, snow sports, snow play, and auto touring21. Approximately 96.85 percent of SEKI is designated and managed as wilderness (838,000 acres).

2.2 SITE HISTORY

Sequoia National Park was established on September 25, 1890. The park spans 404,063 acres. Kings Canyon National Park was established on March 4, 1940, and covers 461,901 acres. It incorporated General Grant National Park, established in October 1, 1890, to protect the General Grant Grove of giant sequoias. Sequoia National Park is south of and contiguous with Kings Canyon National Park; since 1943 the two parks have been administered together by

NPS.

2.2.1 Dump Area Operational History

The history and contents of the dump area were reportedly unknown to the current Park staff, except that the park concessionaires used to burn and dispose of common trash in the area.

The former Lower Kaweah Incinerator (also known as Lodgepole Incinerator) operated from 1931 until 1965 to burn domestic waste. In 1965, the parks began to dispose of the waste off-site. The incinerator was dismantled in around 197522 and demolished in the 1990’s23.

19 National Park Service, “Sequoia and Kings Canyon Nature and Science”, retrieved on 12/17/2013 from http://www.nps.gov/seki/naturescience/index.htm.

20 National Park Service, “Sequoia and Kings Canyon – Fact Sheet 2013”. August 23, 2013.

21 National Park Service, “Sequoia and Kings Canyon – Things To Do”, last updated 05/26/2013, accessed

05/29/2013, http://www.nps.gov/seki/planyourvisit/things2do.htm 22 California Department of Toxic Substances Control. RCRA Facility Assessment, U.S. Department of Interior, National Park Service, Sequoia and Kings Canyon National Parks. August 1997.

http://en.wikipedia.org/wiki/General_Grant_Grove http://en.wikipedia.org/wiki/Sequoiadendron_giganteum http://en.wikipedia.org/wiki/Kings_Canyon_National_Park http://en.wikipedia.org/wiki/National_Park_Service

The dump site was capped in place by NPS in direct consultation with, and with the apparent approval from, DTSC in or around 2000 or 200124.

2.3 SUMMARY OF PREVIOUS INVESTIGATIONS

In August 1998, Kleinfelder, Inc. (Kleinfelder) performed a site investigation25 (SI) at an area of the dumpsite composed mostly of burned materials and ash. Five test pits were excavated through the dump fill material, and five composite soil samples were collected from the sidewalls of the test pits. Four of the five samples collected were analyzed for cadmium, chromium, lead, zinc, nickel, and dioxins. Laboratory analytical results indicated concentrations of the five metals analyzed and dioxins below their Total Threshold Limited Concentration (TTLC) as listed in the California Code of Regulations (CCR), Title 22 and therefore would not be classified as hazardous waste, if the dump fill material were removed for off-site disposal. Initially total lead and zinc concentrations were high enough (744 milligrams per kilogram [mg/kg] and 4,760 mg/kg, respectively) that testing for leaching potential was conducted. The results of citric solubility testing indicated that lead was present at 22.4 milligrams per liter (mg/L) in leachate, which is above its Solubility Threshold Limit Concentration (STLC) of 5.0 mg/l, and therefore would be classified as a California hazardous waste if removed from the site. A toxicity characteristic leaching procedure (TCLP) test was not performed on the sample, so it was unknown if the waste would be classified as a Resource Conservation and Recovery Act (RCRA) hazardous waste if removed from the Site.

In December 2001, Kleinfelder performed an expanded SA26 and excavated eight exploratory trenches in the dumpsite to further define its volume and characterize the fill material. Six exploratory backhoe test pits were excavated near the topographically inferred perimeter of the dumpsite. The test pits were located in a radial pattern around the perimeter of the dump area at distances ranging from approximately 15 to 26 feet, averaging approximately 20 feet from one another. Soil samples were collected from the outer perimeter of each test pit to characterize the outer boundary of the dump.

Additionally, two exploratory 13 foot-long test pits were excavated in the central area of the dump. The two interior test pits were excavated to depths of 5 feet and 9 feet, where underlying bedrock and native material were encountered. Four soil samples were collected from the two interior test pits, two from each test pit. One sample was analyzed to further characterize the dump material and the other sample was used to characterize the native soil laying underneath the dump material above the underlying bedrock. Dioxins were present in the discrete soil samples, with 2,3,7,8-TCDD reported in concentrations up to 5.4 picograms per gram (pg/g).

The maximum concentration was detected in the sample collected at 4 feet bgs from test pit

23 California Department of Toxic Substances Control. Resource Conservation and Recovery Act (RCRA), Facility Assessment of Sequoia and Kings Canyon National Parks. June 3, 2010.

24 National Park Service. Memorandum Subject: Lower Kaweah Incinerator site. January 26, 2000.

25 Kleinfelder, Inc. Site Investigation Report, Giant Forest – Lower Kaweah Dump Area, Sequoia National Park.

November 25, 1998.

26 Kleinfelder, Inc. Lower Kaweah Dump Area Expanded Site Assessment, Sequoia National Park, California.

January 11, 2002.

TP-8, excavated in the interior of the dump area. This concentration is lower than the concentration reported from the composite sample collected in September 1998. Of the organochlorine pesticides, only 4,4-DDT and 4,4-DDE were detected, but at concentrations not exceeding their respective TTLC; therefore, solubility testing for 4,4-DDT and 4,4-DDE was not performed. Of the metals detected, lead and chromium had elevated concentrations and therefore solubility tests were performed on seven soil samples. Solubility testing of lead and chromium indicated lead exceeded its CCR, Title 22, STLC of 5 mg/l; thus, the dump material would be classified as a hazardous waste if removed. TCLP solubility testing for lead did not detect concentrations exceeding the Title 22 value of 5 mg/l, and therefore the dump fill material would not be considered a RCRA hazardous waste if removed.

In 2005, the U.S. Army Corps of Engineers conducted a HERA27 utilizing data collected during Kleinfelder’s investigations. The HERA concluded that no unacceptable human or ecological effects from site contaminants are expected to occur. The HERA assumed that potential receptors would come in direct contact with the contaminated soil and debris, as if no cover was present at any portion of the dump area, theoretically overestimating the risk for actual receptors. No site-specific background concentrations for metals were established in the HERA. The HERA identified the primary constituents of potential concern (COPCs) for ecological receptors to be dioxins/furans, dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloro-ethylene (DDE), and metals. For human receptors, COPCs are dioxins/furans and arsenic. The HERA concluded that no further investigation or further action is required.

2.4 2014 EE/CA FIELD INVESTIGATIONS

As summarized above, the 1998 and 2001 SI and expanded SAs indicated that CERCLA hazardous substances were present at elevated concentrations in materials and soils in the dump area. Because the exact locations of samples collected during both investigations were not clearly identified, and composite samples were collected mixing suspected native, potentially clean soil with impacted soil, the extent of contamination was not clearly defined, which represents a gap in the Site characterization. Although the HERA concluded no human or ecological exposure risk exits, NPS reviewed all available Site information and concluded that the SI and expanded SA did not completely characterize the nature and extent of contamination for purposes of conducting a non-time-critical removal action (NTCRA) and identified the following assessment gaps:

• Quantity (area and depth) of dump fill material and impacted soil exceeding cleanup goals;

• Extent and concentration of impacts above background; and

• Waste classification of the dump fill material and impacted soil for potential off-site disposal.

27 U.S. Army Corps of Engineers, Sacramento District, Environmental Design Section, Human Health and Ecological Risk Evaluation Lower Kaweah Dump Area, Sequoia National Park, California, Draft, August 2005.

In order to address these gaps in the characterization of contamination, NPS directed ECM to prepare and perform a Work Plan28, including a Sampling and Analysis Plan (SAP) and Quality Assurance Project Plan29 (QAPP), to address the remaining data needs for a complete Site characterization.

ECM conducted an initial field visit on November 11, 2013, to support Work Plan development.

ECM observed the Lower Kaweah dumpsite and collected global positioning system (GPS) locations around the perimeter of the visible waste material and inferred dumpsite.

The southern slope of the dumpsite was exposed, revealing ash and debris. Many young cedar trees were growing within the waste area. Small erosion rills were observed across the level portion of the dump material and remaining thin cap. ECM identified locations for equipment staging and confirmed these locations with NPS staff.

In May 2014, ECM collected additional site data to characterize the nature and extent of potential contamination in soil at and near the Lower Kaweah dumpsite during the execution of the Work Plan. In accordance to the Work Plan, ECM separated fieldwork activities into three tasks:

1. Dump area delineation;

2. Background soil characterization; and,

3. Dumpsite fill material and impacted soil characterization.

Surface water in the vicinity of the Site is ephemeral and only occurs for hours or days following rainfall or snowmelt. No surface water was present during site assessment activities; therefore no surface water samples were collected.

Dumpsite Area Delineation ECM defined the perimeter and depth of the dump area in order to estimate its total volume by digging four trenches using a small backhoe. Additionally, the thickness of the soil cover, areas without soil cover, areas with underlying bedrock, and thickness of soil between bedrock and fill material in the excavate trenches was defined by direct observation. ECM carefully mapped all trenches using a GPS device and indicated the boundaries of the dump area on Figure 2.3.

Attachment E includes photographs of field activities.

Background Characterization

ECM implemented incremental sampling methodology30 (ISM) to characterize background concentrations of COPCs, listed below, excluding dioxins and furans, within the Site vicinity.

ISM is a technique designed to statistically reduce or limit variability associated with discrete

28 Environmental Cost Management, Inc. (ECM), 2014. Work Plan for Additional Soil Assessment, Sequoia and Kings Canyon National Parks, Three Rivers, CA. March 6.

29 ECM, 2014. Sampling and Analysis Plan / Quality Assurance Project Plan for Site Characterization at Lower Kaweah Area Dumpsite, Sequoia and Kings Canyon National Parks, Three Rivers, California. January 31.

30 ITRC, Technical and Regulatory Guidance, Incremental Sampling Methodology, February 2012.

sampling. ISM provides a representative and reproducible estimate of the mean concentration of analytes in a specific area of interest, known as a decision unit (DU).

ECM collected ISM background samples from one DU. The DU had an area of approximately 60 feet by 50 feet, divided into a grid of thirty, 10-foot by 10-foot, sections (Figure 2.4). ECM collected four background samples using ISM within the DU, consisting of 30 multi-increment (MI) portions, each MI subsample weighed approximately 50 grams (g). The sampling methodology was such that the total amount of soil collected was approximately 1.5 kilograms

(kg) of soil for each of the four samples.

Laboratory analysis results from samples collected from the DU provided information regarding background concentrations near the Site for an approximate soil volume of 3,000 cubic feet.

Results for background sampling are presented in Attachment B, Table B-1.

Dump Fill Material and Adjacent Soil Characterization

ECM dug four perimeter trenches and two interior trenches to characterize potentially impacted waste and native soils in contact with waste material. Figure 2.3 shows the observed perimeter of dump fill material and the trenching locations. ECM collected discrete soil samples representative of fill material and adjacent native soil at the immediate interface where waste material contacted native soil at the edge of the dump pile.

Samples were analyzed for the following COPCs:

• CAM 17 Metals by EPA method 6010B;

• Mercury by EPA method 7471A;

• Dioxins and Furans by EPA method 8290;

• Diesel Range Organics by EPA method 8015B;

• Semi-Volatile Organic Compounds by EPA method 8270C;

• Herbicides by EPA method 8151A;

• Organochlorine Pesticides by EPA method 8081A; and,

• Polychlorinated Biphenyls (PCBs) by EPA method 8082.

Additionally, ECM submitted two soil samples, SEKI1 and SEKI2, for phytoremediation/ agricultural parameters, specifically:

• Soil salinity,

• Soil texture, and

• Percent water saturation.

Laboratory reports for samples collected in May 2014 are presented in Attachment B and results are summarized in Table B-1 through Table B-6. Table B-7 presents a comparison of 95 percent upper confidence limit (95% UCL) estimated values for background, waste stream and adjacent native soil analytical sample results.

Arsenic, barium, cadmium, copper, chromium, lead and zinc were detected at concentrations greater than 10 times their STLC and/or greater than 20 times their TCLP in some samples collected at the waste stream area (Table B-2). STLC tests were not performed because sample SEKI-T03-05-3 had a reported lead concentration of 1,200 mg/kg that exceeds the TTLC for lead of 1,000 mg/kg and samples SEKI-T05-09-7 and SEKI-T06-10-5 had reported zinc concentrations of 9,800 mg/kg and 11,000 mg/kg, respectively. These values exceed the TTLC for zinc of 2,500 mg/kg. Therefore the soil from the dump site area is considered non- RCRA California hazardous waste if disposed off-site. If the waste is transported and disposed off-site, TCLP analyses will be required for complete characterization.

No semivolatile organic compounds (SVOCs) (Table B-3) were detected in any of the samples.

In addition, diesel range…