American Samoa Wetland/Stream Restoration and Enhancement Plan

Asili Stream

AMERICAN SAMOA WETLAND/STREAM RESTORATION AND ENHANCEMENT PLAN

Vatia Wetland

AMERICAN SAMOA WETLAND/STREAM RESTORATION AND ENHANCEMENT PLAN

Prepared for:

American Samoa Environmental Protection Agency and American Samoa Coastal Management Program Pago Pago, American Samoa 96799

Prepared by:

Pedersen Planning Consultants P. O. Box 1075 Saratoga, Wyoming 82331-1075 Tel: (307) 327-5434 Fax: (307) 327-5210 E-mail: [email protected]

February 2001 American Samoa Wetland/Stream Restoration and Enhancement Plan TABLE OF CONTENTS

Chapter No. Title Page No.

One INTRODUCTION 1-1 Purpose 1-1 Scope 1-1 Organization of the Report 1-3 Plan Methodology 1-3 Public Consultation 1-6 Two TULA WETLAND 2-1 Location 2-1 Wetland Hydrology 2-1 Wetland Vegetation 2-5 Aquatic Fish and Invertebrates 2-6 Land Uses in the Vicinity of Tula Wetland 2-7 Wetland Restoration and Enhancement Strategies 2-7 Three ALAO WETLAND 3-1 Location 3-1 Wetland Hydrology 3-1 Wetland Vegetation 3-4 Aquatic Fish and Invertebrates 3-7 Land Uses in the Vicinity of Taufusi Marsh 3-8 Wetland Restoration and Enhancement Strategies 3-9 Four AOA WETLAND 4-1 Location 4-1 Wetland Hydrology 4-1 Wetland Vegetation 4-5 Aquatic Fish and Invertebrates 4-8 Land Uses in the Vicinity of Aoa Wetland 4-9 Wetland Restoration and Enhancement Strategies 4-10 Five VATIA WETLAND 5-1 Location 5-1 Wetland Hydrology 5-1 Wetland Vegetation 5-5 Aquatic Fish and Invertebrates 5-7 Land Uses within Southeast Wetland and Faatafe Stream 5-9 Wetland Restoration and Enhancement Strategies 5-9 Six VAIPITO STREAM 6-1 Location 6-1 Stream Hydrology 6-1 Vegetation 6-5 Aquatic Fish and Invertebrates 6-7 Land Uses Adjacent to Vaipito Stream 6-10 Riparian Restoration and Enhancement Strategies 6-10

- i - American Samoa Wetland/Stream Restoration and Enhancement Plan TABLE OF CONTENTS (continued)

Chapter Title Page No. No.

Seven PAPA STREAM 7-1 Location 7-1 Stream Hydrology 7-1 Vegetation 7-7 Aquatic Fish and Invertebrates 7-8 Land Uses Adjacent to Papa Stream 7-9 Riparian Restoration and Enhancement Opportunities 7-9 Eight SAUINO STREAM 8-1 Location 8-1 Stream Hydrology 8-1 Vegetation 8-5 Aquatic Fish and Invertebrates 8-6 Land Uses Adjacent to Lower Sauino Stream 8-7 Riparian Restoration and Enhancement Opportunities 8-7 Nine LEAFU STREAM 9-1 Location 9-1 Stream Hydrology 9-1 Vegetation 9-5 Aquatic Fish and Invertebrates 9-7 Land Uses Adjacent to Vaipito Stream 9-9 Riparian Restoration and Enhancement Opportunities 9-9 Ten ASILI STREAM 10-1 Location 10-1 Stream Hydrology 10-1 Vegetation 10-6 Aquatic Fish and Invertebrates 10-7 Land Uses Adjacent to Asili Stream 10-9 Riparian Restoration and Enhancement Opportunities 10-10 Eleven FUSI WETLAND 11-1 Location 11-1 Wetland Hydrology 11-1 Wetland Vegetation 11-4 Aquatic Fish and Invertebrates 11-5 Land Uses in the Vicinity of Fusi Wetland 11-6 Wetland Restoration and Enhancement Strategies 11-7 Twelve FUTURE PROGRAM MANAGEMENT 12-1 Recommended Program Participants 12-1 Individual Project Assignments 12-1 Selected Agency Assignments 12-3 Potential Participation from Other Community Organizations 12-3 APPENDIX A – Summary of Plants, November 1999 APPENDIX B – Summary of Aquatic Macrofaunal Organisms, November 1999 APPENDIX C – Summary of Aquatic Macrofaunal Organisms, July 1981 REFERENCES

- ii - American Samoa Wetland/Stream Restoration and Enhancement Plan LIST OF FIGURES

Figure No. Title Page No.

1-1 Location Map 1-2 Potential Wetlands and Streams Enhancement Opportunities 2-1 Location Map, Tula Wetland 2-2 2-2 Existing Conditions, Tula Wetland 2-3 2-3 Option 2: Detention of Stormwater Within Tula Wetland 2-9 2-4 Option 3: Expansion of Taro Production Within Tula Wetland 2-11 2-5 Resource Monitoring Stations and Areas, Tula Wetland 2-20 3-1 Location Map, Alao Village Wetland 3-2 3-2 Existing Conditions, Taufusi Marsh 3-3 3-3 FEMA 100-Year Flood Plain, Alao Village 3-5 3-4 Option 2: Restore Taro Production 3-10 4-1 Location Map, Aoa Village Wetland 4-2 4-2 Existing Conditions, Aoa Wetland 4-3 4-3 Option 4: Clear Puna Stream Culvert, Plant Trees 4-12 4-4 Resource Monitoring Areas 4-18 5-1 Location Map, Southeast Wetland in Vatia 5-2 5-2 Existing Conditions, Vatia Wetland 5-3 5-3 Option 1:Restore Mangrove Forest Upstream of Faatafe Stream Mouth 5-10 6-1 Location Map, Vaipito Stream Drainage 6-2 6-2 Existing Conditions, Vaipito Stream 6-3 6-3 Fish and Invertebrate Survey Locations 6-8 6-4 Option 1:Restore Mangrove Forest Along Lower Vaipito Stream 6-11 7-1 Location Map, Leele-Papa-Tauese Stream Drainage 7-2 7-2 Existing Conditions, Papa Stream Segment 7-3 7-3 Option 2: Clean Stream, Improve Stream Hydrology, and 7-12 Reduce Bank Erosion 8-1 Location Map, Sauino Stream Drainage 8-2 8-2 Existing Conditions, Sauino Stream 8-3 8-3 Option 1: Construct Detention Pond 8-8 8-4 Option 2: Plant Native Riparian Trees Along Stream Bank 8-10 9-1 Location Map, Leafu Stream 9-2 9-2 Existing Conditions, Leafu Stream 9-3 9-3 Option 1: Restore Stream Bank in Vicinity of L2 9-10 9-4 Option 2: Construct Basaltic Wall, Stabilize Stream Bank, and Enhance 9-12 Riparian Vegetation 9-5 Option 3: Stabilize East Stream Bank and Enhance Riparian Vegetation 9-13 10-1 Location Map, Asili Stream 10-2 10-2 Existing Conditions, Asili Stream 10-3 10-3 Option 1: Clean Asili Stream and Enhance Riparian Vegetation 10-11 11-1 Location Map, Fusi Wetland 11-2 11-2 Existing Conditions, Fusi Wetland 11-3 11-3 Option 1: Remove Solid Waste Material and Plant Wetland Marsh 11-8 Vegetation

- iii - American Samoa Wetland/Stream Restoration and Enhancement Plan LIST OF TABLES

Table No. Title Page No.

2-1 Potential Stormwater Discharges into Tula Wetland 2-4 2, 10, 50 and 100-Year Storm Events 2-2 Comparative Evaluation 2-13 Wetland Restoration and Enhancement Opportunities Tula Wetland 2-3 Preliminary Cost Estimate 2-14 Development of Channel and Detention Pond Vailoa Stream Drainage and Tula Wetland 2-4 Preliminary Cost Estimate 2-15 Planting of Wetland and Fruit Trees Along Tula Wetland Margin 2-5 Long-term Resource Monitoring Requirements, Tula Wetland 2-17 2-6 Field Monitoring Worksheet, Tula Wetland 2-18,19 3-1 Potential Stormwater Discharges into Taufusi Marsh 3-4 From Mulivaitele Stream and Its Tributaries 2, 10, 50 and 100-Year Storm Events 3-2 Summary of Macrofaunal Organisms, Mulivaitele Stream 3-8 3-3 Relative Abundance and Diversity of Fish and Invertebrates 3-8 Mulivaitele Stream Segment on East Side of Taufusi Marsh 3-4 Comparative Evaluation 3-12 Wetland Restoration and Enhancement Opportunities Alao Wetland 3-5 Preliminary Cost Estimate 3-12 Procurement and Distribution of Taro Plant Cuttings Alao Village 3-6 Long-Term Resource Monitoring Requirements, Alao Wetland 3-14 3-7 Field Monitoring Worksheet, Alao Wetland 3-15,16 4-1 Median Stream Flow Estimate, Lepa Stream 4-1 4-2 Potential Stormwater Discharges into Aoa Wetland 4-4 From Tapua and Puna Streams 2, 10, 50 and 100-Year Storm Events 4-3 Summary of Macrofaunal Organisms 4-9 Alao Wetland and Lepa Stream 4-4 Relative Abundance and Diversity of Fish and Invertebrates 4-9 Tapua Stream and Lepa Stream 4-5 Comparative Evaluation 4-13 Wetland Restoration and Enhancement Opportunities Aoa Wetland 4-6 Preliminary Cost Estimate 4-14 Initial Clearing of Puna Stream Culvert 4-7 Preliminary Cost Estimate 4-14 Planting of Mangrove and Riparian Trees Upstream of Tapua and Puna Stream Mouths 4-8 Long-Term Resource Monitoring Requirements, Aoa Wetland 4-16 4-9 Field Monitoring Worksheet, Aoa Wetland 4-17

- iv - American Samoa Wetland/Stream Restoration and Enhancement Plan LIST OF TABLES (continued)

Table No. Title Page No.

5-1 Potential Stormwater Discharges Along SE Side of Vatia Bay 5-4 2, 10, 50 and 100-Year Storm Events 5-2 Summary of Macrofaunal Organisms 5-8 Vatia Wetland 5-3 Relative Abundance and Diversity of Fish and Invertebrates 5-8 Faatafe Stream 5-4 Comparative Evaluation 5-12 Wetland Restoration and Enhancement Opportunities Vatia Wetland 5-5 Preliminary Cost Estimate 5-12 Clearing of Faatafe Stream Mouth, Culvert, and Upstream Area 5-6 Preliminary Cost Estimate 5-13 Planting of Mangrove and Riparian Trees Upstream of Faatafe Stream Mouth 5-7 Long-Term Resource Monitoring Requirements, Vatia Wetland 5-15 5-8 Field Monitoring Worksheet, Vatia Wetland 5-16,17 6-1 Median Stream Flow Estimates, Tributaries of Vaipito Stream 6-4 6-2 Stormwater Runoff Discharges into Inner Pago Pago Harbor 6-4 From Vaipito Stream Drainage 2, 10, 50 and 100 Year Storm Events 6-3 Estimated Vaipito Stream Capacities 6-5 6-4 Summary of Macrofaunal Organisms 6-9 Vaipito Stream Drainage 6-5 Relative Abundance and Diversity of Fish and Invertebrates 6-9 Vaipito Stream 6-6 Comparative Evaluation 6-13 Riparian Restoration and Enhancement Opportunities Lower Vaipito Stream 6-7 Preliminary Cost Estimate 6-14 Clearing of Lower Vaipito Stream Mouth and Upstream Area 6-8 Preliminary Cost Estimate 6-14 Planting of Trees Upstream of Vaipito Stream Mouth 6-9 Long-Term Resource Monitoring Requirements, Vaipito Stream 6-16 6-10 Field Monitoring Worksheet, Vaipito Stream 6-17,18,19 7-1 Median Stream Flow Estimate, Papa Stream 7-5 7-2 Stormwater Discharges from Papa Stream Into Pala Lagoon 7-6 2, 10, 50 and 100 Year Storm Events 7-3 Cross-Sectional Analysis 7-6 Along Papa Stream Segment 7-4 Summary of Macrofaunal Organisms 7-8 Papa Stream 7-5 Relative Abundance and Diversity of Fish and Invertebrates 7-9 Papa Stream

- v - American Samoa Wetland/Stream Restoration and Enhancement Plan LIST OF TABLES (Continued)

Table No. Title Page No.

7-6 Comparative Evaluation 7-11 Riparian Restoration and Enhancement Opportunities Lower Papa Stream 7-7 Preliminary Cost Estimate 7-13 Clearing of Lower Papa Stream Mouth 7-8 Preliminary Cost Estimate 7-14 Propagation and Planting of Native Riparian Trees Lower Papa Stream 7-9 Long-Term Resource Monitoring Requirements, Papa Stream 7-16 7-10 Field Monitoring Worksheet, Papa Stream 7-17,18,19 8-1 Median Stream Flow Estimate, Sauino Stream 8-4 8-2 Stormwater Discharges from Sauino Stream into Pala Lagoon 8-4 1, 20, 50 and 100-Year Storm Events 8-3 Summary of Macrofaunal Organisms 8-6 8-4 Relative Abundance and Diversity of Fish and Invertebrates 8-7 Lower Sauino Stream Segment 8-5 Comparative Evaluation 8-11 Riparian Restoration and Enhancement Opportunities Lower Sauino Stream Segment 8-6 Preliminary Cost Estimate 8-11 Planting of Riparian Trees Along Lower Sauino Stream 8-7 Long-Term Resource Monitoring Requirements, Sauino Stream 8-13 8-8 Field Monitoring Worksheet, Sauino Stream 8-14,15,16 9-1 Measurements from Selected Stream Cross Sections, Leafu Stream 9-4 9-2 Median Stream Flow Estimates, Leafu Stream 9-4 9-3 Stormwater Runoff Discharges into Leone Pala 9-5 10, 50, and 100-Year Storm Events 9-4 Summary of Macrofaunal Organisms 9-8 Leafu Stream 9-5 Relative Abundance and Diversity of Fish and Invertebrates 9-8 Lower Leafu Stream 9-6 Comparative Evaluation 9-14 Riparian Restoration and Enhancement Opportunities Lower Leafu Stream Segment 9-7 Preliminary Cost Estimate 9-15 Propagation and Planting of Riparian Trees Along Lower Leafu Stream 9-8 Long-Term Resource Monitoring Requirements, Leafu Stream 9-17 9-9 Field Monitoring Worksheet, Leafu Stream 9-18,19

- vi - American Samoa Wetland/Stream Restoration and Enhancement Plan LIST OF TABLES (Continued)

Table No. Title Page No.

10-1 Median Stream Flow Estimate, Asili Stream 10-4 10-2 Stormwater Discharges from Asili Stream 10-5 1, 10, 50 and 100-Year Storm Events 10-3 Cross-Sectional Analysis 10-5 Along Asili Stream Segment 10-4 Summary of Macrofaunal Organisms 10-9 Asili Stream 10-5 Relative Abundance and Diversity of Fish and Invertebrates 10-9 Asili Stream 10-6 Comparative Evaluation 10-12 Riparian Restoration and Enhancement Opportunities Lower Asili Stream 10-7 Preliminary Cost Estimate 10-13 Clean-up of Lower Asili Stream 10-8 Preliminary Cost Estimate 10-13 Propagation and Planting of Native Riparian Trees Lower Asili Stream 10-9 Long-Term Resource Monitoring Requirements, Asili Stream 10-15 10-10 Field Monitoring Worksheet, Asili Stream 10-16,17,18 11-1 Relative Abundance and Diversity of Fish and Invertebrates 11-6 Fusi Wetland 11-2 Comparative Evaluation 11-9 Wetland Restoration and Enhancement Opportunities Fusi Wetland 11-3 Preliminary Cost Estimate 11-10 Collection, Removal and Hauling of Solid Waste Material Fusi Wetland 11-4 Preliminary Cost Estimate 11-10 Propagation and Planting of Coastal Marsh Vegetation Fusi Wetland 11-5 Long-Term Resource Monitoring Requirements, Fusi Wetland 11-12 11-6 Field Monitoring Worksheet, Fusi Wetland 11-13

- vii - Chapter One INTRODUCTION

PURPOSE

The American Samoa Environmental Protection Agency, in cooperation with several other agencies of the American Samoa Government, is undertaking resource management efforts to conserve natural resources on a watershed-by-watershed basis. The American Samoa Watershed Protection Plan provided management recommendations for 41watershed planning areas and recommended the establishment of a Territorial Watershed Resource Management Board to coordinate future implementation. While the Watershed Protection Plan recommends a wide variety of resource conservation efforts, it is envisioned that a series of more specific resource conservation plans that will eventually supplement and support the recommendations outlined in the American Samoa Watershed Protection Plan.

The Wetland/Stream Restoration and Enhancement Plan is one example of a more specific resource conservation plan. This plan outlines a more specific strategy for the conservation of five streams and four wetlands on the Island of Tutuila, as well as one wetland on the Island of Tau (Figure 1-1). This information will guide a portion of the future work of the proposed ASG Watershed Resource Management Board as it determines specific watershed management priorities in several watershed planning areas of the Territory. The Plan will also provide more specific technical guidance to the various agencies of the American Samoa Government who will work cooperatively to accomplish the actions necessary to implement conservation efforts at various streams and wetlands.

SCOPE

In 1999, representatives of the American Samoa Coastal Management Program, American Samoa Community College Land Grant Program, and American Samoa Environmental Protection Agency evaluated potential opportunities for the restoration and enhancement of various streams and wetlands. In recognition of available funding, the number of stream and wetland sites selected for site evaluation and planning was limited to ten locations.

This plan examines potential resource management opportunities to enhance the quality and function of five streams and five wetlands. The primary questions addressed with the evaluation of each potential resource location are:

1) What feasible opportunities exist for enhancing stream and wetland functions? 2) What potential benefits would be gained from enhancement efforts? 3) What is the anticipated cost of a potential enhancement program at each site? 4) Where feasible, how should enhancement efforts be monitored? 5) Who should carry out recommended enhancement efforts?

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Introduction, Page 1-1 Figure 1-1 Location of Potential Wetlands and Streams Enhancement Opportunities

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Introduction, Page 1-2 ORGANIZATION OF THE REPORT

The Wetland and Stream Enhancement Plan report is organized in the following manner.

Chapter One: Introduction Chapter Two: Tula Wetland Chapter Three: Alao Wetland Chapter Four: Aoa Wetland Chapter Five: Vatia Wetland Chapter Six: Vaipito Stream Chapter Seven: Papa Stream Chapter Eight: Sauino Stream Chapter Nine: Leafu Stream Chapter Ten: Asili Stream Chapter Eleven: Fusi Wetland (Island of Tau) Chapter Twelve: Future Program Management

Each site evaluation describes the characteristics and condition of stream and wetland hydrology, vegetation, as well as fish and invertebrates. The significance of these resources is evaluated in terms of potential enhancement opportunities. Adjacent land uses are also examined in the context of relevant resource management issues that may influence the approach to potential restoration and enhancement opportunities.

Practical options for wetland and stream restoration and enhancement are provided for each of the ten sites. The benefits and consequences of potential options are compared and evaluated. The recommended restoration and enhancement project for each site is described in terms of scope, location, and anticipated costs.

A number of overall program management recommendations are also presented in Chapter Twelve to facilitate future project implementation. These recommendations include considerations of project management, potential program participants, as well as related responsibilities and project coordination.

PLAN METHODOLOGY

Research of Other Stream and Wetland Restoration Enhancement Projects

Pedersen Planning Consultants (PPC) initiated the project with a literature search for selected stream and restoration projects on Pacific Islands, South America, and the continental United States. An Internet search was used to explore a wide range of stream and wetland enhancement projects, as well as relevant criteria for the evaluation and assessment of potential enhancement opportunities.

Mr. Dick Wass, manager of the Hakalau Wildlife Refuge on the Island of Hawaii, was interviewed by PPC in December 1998. Through his experience with the U.S Fish and Wildlife Service and past experience in American Samoa, Mr. Wass provided some insights concerning the enhancement of wildlife opportunities.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Introduction, Page 1-3 Onsite Investigations

November 1999

General

Following initial site selection, PPC sent a field team of three persons to American Samoa to investigate each of the stream and wetland sites in November 1999. PPC field team members included:

Jim Pedersen, principal planner, Pedersen Planning Consultants Art Whistler, botanist, Isle Botanica Charles Chong, aquatic biologist

Prior to accessing specific sites, the field team made a reasonable attempt to locate and speak with, at least, one traditional village matai, or a pulenuu of the village. The purpose of the site visit was explained. Permission was requested to enter the site. In most cases, other questions relating to existing conditions and specific resource management issues were also posed and discussed with the selected village representatives and, in some cases, other village residents encountered during the survey.

When schedules permitted, the field team was accompanied by Bronwyn Mitchell, project manager and wetland specialist with the American Samoa Coastal Management Program, or Colin Steele, director of the American Samoa Community College, Land Grant Program. Both of these ASG representatives provided valuable insights concerning onsite conditions and potential resource enhancement opportunities.

Field notes and digital photos were taken of selected resource conditions. Digital photos were later incorporated into a digital photo album for the project. Information gained from village representatives and residents were also documented.

Vegetation Survey

A qualitative survey was also made of vegetation along selected stream segments and wetland areas. The extent and location of observations at each site varied depended primarily upon stream hydrology characteristics, land uses, and site accessibility. The specific areas surveyed are more specifically mapped and/or described within each site description.

The type and relative abundance of the species observed at each site were recorded. In some cases, specific plants were photographed to facilitate future reference.

During the survey, special attention was given to plant species that might be threatened or endangered. Determinations were made concerning the type of wetland and stream environments, their general boundaries, and which species were dominant.

A plant checklist was prepared for all plants observed during the survey (Appendix A). This checklist identified scientific, Samoan and English names of all plants observed, and provided useful notations concerning the wetland status of each plant. The categories of wetland status used in the checklist included the following:

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Introduction, Page 1-4

• Obligate plant represented any plant species found only in wetlands; • Facultative wetland plant included any plant species that is usually, but not always, found in wetlands; • Facultative plant was considered to be any plant species that is found as much in wetlands as in dry soil; • Facultative upland plant represented any plant that is usually found in upland areas, but sometimes in wetlands; and, • Upland plant was considered to be any plant that is rarely, if ever, found in wetlands.

Fish and Invertebrate Survey

A one-time, qualitative survey of aquatic fish, crustaceans, and mollusks was made at stream segments and selected wetland areas. Two sites, i.e., stream mouth and an upland stream location, were sampled for streams that flowed into the ocean at the time of the survey. The extent and location of observations at each site varied depended primarily upon stream hydrology characteristics, land uses, and site accessibility. The specific areas surveyed are mapped and/or described within each site description. An overall summary of macrofaunal organisms observed is presented in Appendix B.

Fish and invertebrate survey sites were approximately 30 meters long. Each site was inspected moving upstream and all macrofaunal organisms were visually recorded. The types of species, relative abundance, and general diversity were documented for stream mouth, upland stream, and wetland sites. Visual observations were made at the surface, as well as underwater where adequate flow was present.

Three Surber samples were made at survey sites where cobble substrata were present and stream flow velocities were sufficient. The Surber samples were taken in the middle of the stream approximately 10 meters apart. If substrata and stream flow characteristics were not appropriate for use of the Surber net, three individual rocks in a site were selected and cleaned completely with a stiff brush to collect and benthic invertebrates present. However, there was only one species of chironomid larvae found in very low densities in any of the samples. Consequently, no results were reported for benthic fauna.

Wetland and Stream Hydrology Assessment

PPC also made assessments of stream hydrology at each wetland and stream site to identify potential opportunities for wetland and stream restoration and enhancement. A walk through was made along selected stream channels and wetlands to ascertain the potential locations, causes, and impacts of:

• significant stream bank erosion; • changes in stream flow path; • stream modifications such as man-made stream channels; • impeded surface water discharges to and from wetlands; and, • changes in land uses along stream channels, as well as within and along the perimeter of wetlands.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Introduction, Page 1-5 Where appropriate, stream cross sections were measured at 100-foot intervals to facilitate the subsequent modeling of stormwater discharge capacities and long-term monitoring of stream characteristics. Digital photos were taken of significant stream and wetland characteristics.

In 1998 and 1999, Pedersen Planning Consultants had previously modeled and quantified potential storm runoff and sedimentation from 2, 10, 50 and 100-year storm events for Papa, Sauino, Vaipito, and Leafu streams, as well as the Tula wetland. PPC also had evaluated potential stormwater detention opportunities at these and several other sites on the Island of Tutuila. Consequently, PPC was already aware of flow capacity issues for several of the sites being evaluated in the Wetland and Stream Restoration and Enhancement Plan. The capacity of the remaining stream and wetland sites included in the Wetland and Stream Restoration and Enhancement Plan were modeled following completion of the November, 1999 field survey.

Changes in land use were also documented by PPC and compared to land use survey information obtained by PPC in December, 1994. This information was collected and incorporated into the GIS developed for ASEPA in 1998 and 1999.

Information gained from field observations, hydraulic modeling data, and discussions with local residents enabled PPC to evaluate hydrologic options for stream bank stabilization, the restoration of stream flow paths, and the detention of stormwater flows within selected wetlands.

June 2000

A second reconnaissance was made of selected segments of lower Papa Stream in June 2000. This brief survey was made by Joshua Craig of the American Samoa Environmental Protection Agency and Jim Pedersen of Pedersen Planning Consultants.

Stream modifications immediately downstream and upstream of a former Navy weir were surveyed. Digital photos were taken of stream bank alterations along the west stream bank that were completed after the November, 1999 field survey. PPC also observed stream modifications several hundred feet upstream of the former Navy weir (see Chapter Seven) where stream modifications had apparently generated significant downstream bank erosion and altered the stream flow path. Local residents also provided valuable insights concerning the causes and effects of past and recent stream modifications.

PUBLIC CONSULTATION

The following individuals and agency representatives were contacted during the course of this project. Their insights and experience provided useful information to the PPC project team.

American Samoa Environmental Protection Agency Sheila Wiegman, deputy director Joshua Craig, environmental scientist

American Samoa Coastal Management Program Bronwyn Mitchell, wetland specialist

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Introduction, Page 1-6 American Samoa Community College, Land Grant Program Colin Steele, ASCC/AHNR Project Forester

Asili Village Senator Tago, matai and faipule Petasi Toita, matai and 80-year resident of Asili Village

Alao Village Tulafale Satele, talking chief Malia Puaauli, resident on southeast side of Alao wetland

Aoa Village Tautala Taase, matai and pulenuu Faamaoni Afusia, resident on northwest side of Aoa wetland

Leone Village Tui Faafili, 20-year resident of Leone

Nuuuli Village Sainila Fanene, matai Aiakopu Samuelo, resident and building contractor George Galeai, building contractor and resident along Papa Stream

Tula Village Faasou Pulou, matai

U.S. National Park Service Peter Craig

U.S. Fish and Wildlife Service, Hakalau Wildlife Refuge, Island of Hawaii Dick Wass, Manager

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Introduction, Page 1-7 Chapter Two TULA WETLAND

LOCATION

Tula Village is located along the southeast coast of the Island of Tutuila (Figure 2-1). The Tula wetland is located on the northwest side of Tula Village (Figure 2-2). Past studies suggest that the wetland comprises approximately 8 acres of land area (Biosystems Analysis, 1992). More recent studies by PPC indicate that the size of the wetland has now reduced to about 7.7 acres.

WETLAND HYDROLOGY

Sources of Surface Runoff to the Tula Wetland

In a recent evaluation of potential stormwater management opportunities, Pedersen Planning Consultants (PPC) noted the following surface water contributions to the Tula wetland.

“The wetland receives surface runoff via overland flows from upland slopes south and west of the wetland. Along the north side of the wetland, two 4x8-foot culverts underneath the primary shoreline roadway enable the transport of some runoff from upland slopes adjacent to the northeast corner of the wetland” (Pedersen Planning Consultants, 2000).

Field observations by PPC in May 1998 and November 1999 found no surface connections between Vailoa Stream, and/or the man-made swale through Tula Village, to the wetland. The hydrologic connection between Vailoa Stream and the Tula wetland was thwarted by a somewhat higher stream elevation of Vailoa Stream upstream of a second set of two 4x8-foot culverts that are underneath the primary shoreline roadway.

At one time, Vailoa Stream was the primary source of surface runoff to the Tula wetland. However, more recent flooding and related discharges of sediment likely created a higher stream elevation. During re-construction of the primary shoreline roadway in 1994-1995, it is also possible that some stream material, which was removed by contractors to install the two 4x8-foot culverts, was conveniently placed upstream of the culverts to avoid hauling of excavated material to another site.

Vailoa Stream also represents the hydrologic outlet for the Tula wetland. The two 4x8-foot culverts underneath the primary shoreline roadway are capable of transporting stormwater flows from both Vailoa Stream and the Tula wetland to the mouth of Vailoa Stream. However, the discharge of stormwater flows to the mouth of Vailoa Stream is hampered by higher stream elevations immediately upstream of the wetland, as well as the gradual filling of the Tula wetland.

Stream Flows Along Vailoa Stream

Median Stream Flows

Nine intermittent stream flow measurements between 1958 and 1965 were used, in part, by the U.S. Geological Survey (USGS) to estimate median stream flows along Vailoa Stream. In 1996, USGS estimated that median stream flow was approximately 0.02 cubic feet per second (Wong, 1996).

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-1 Figure 2-1 Location Map Tula Wetland

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-2 Figure 2-2 Tula Wetland Existing Conditions

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-3 Stormwater Discharges and Related Flood Potential

Pedersen Planning Consultants made a hydrologic analysis of Vailoa Stream in 1998 to determine the potential amount of stormwater that could be discharged into the Tula wetland.

TABLE 2-1 POTENTIAL STORMWATER DISCHARGES INTO TULA WETLAND 2,10,50, AND 100-YEAR STORM EVENTS IN CUBIC FEET PER SECOND (CFS)

Location 2-Year Storm 10-Year Storm 50-Year Storm 100-Year Storm

All Surface Runoff 244 465 735 944

Source: Pedersen Planning Consultants, 1998

Through hydraulic modeling, PPC determined that potential stormwater discharges along Vailoa stream could range from 244 cubic feet per second (cfs) for a 2-year storm and about 944 cfs for a 100-year storm.

The areal extent of flood potential associated with an 11-year storm event was mapped by the Federal Emergency Management Agency (FEMA) in May 1991. When this information is correlated with digital building location data from the American Samoa GIS, it is clear that a 100-year flood event would clearly impact most of the inhabited village area.

In January 2000, representatives of the American Samoa Coastal Management Program observed flooding in the vicinity of the Tula wetland and along the lower Vailoa Stream drainage. This flooding was generated from a stormwater event that occurred January 20 through January 22, 2000. Climatological data from the National Weather Service station at Pago Pago International Airport recorded 6.41 inches of rainfall during this period. Available records from NOAA’s Cape Matatula station near Tula Village indicate that the station made no measurements during the January 20-22 period.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-4 Improved channelization of stormwater flows is needed to help reduce potential damages to residential and commercial property in the village. Following higher rainfall events, surface stormwater flows upland of the village has repeatedly spread over much of the upland portion of the inhabited village area. As a result, various homes in the upland village area have been flooded. The capacity of the lower portion of Vailoa Stream is inadequate to accommodate larger stormwater flows. The lower stream channel has likely been altered over the years to accommodate gradual residential expansion in the upland village area. In addition, the present blockage of the lower stream channel increases the areal extent of potential flooding and property damage resulting from a 100-year storm and less severe storm events.

Construction of a second upland channel would help alleviate present flooding in the upland area and, at the same time, enable the transport of stormwater flows to the wetland. One desirable use of the Tula wetland would be stormwater detention. Restoration of this wetland function would help reduce the amount of sedimentation that can be generated from Vailoa Stream. Stormwater detention would also permit the treatment and recharge of stormwater into the fringe of the basal aquifer.

WETLAND VEGETATION

November 1999 Survey

Art Whistler of Isle Botanica conducted a botanical survey of the Tula wetland on November 2 and 17, 1999. Mr. Whistler was part of a three-person field survey team organized by Pedersen Planning Consultants that observed wetland vegetation, habitat for aquatic fish and invertebrates, stream hydrology, as well as land uses within and adjacent to the wetland. His observations are summarized in the following paragraphs.

West Side of Vailoa Stream

Vegetation observed within the Tula wetland along the west side of Vailoa Stream was not representative of a wetland. Vegetation along the stream banks represented a mixture of typical wetland or wetland margin plants such as Coix lacryma-jobi sanasana (Job’s tears), Paspalum conjugatum vao lima (T-grass), and more typical upland species such as Nephrolepis hirsutula vao tuaniu (sword fern). A few Hibiscus tiliaceus fau (beach hibiscus) and Barringtonia samoensis falaga were also evident along the stream banks.

Southwest of the Primary Shoreline Roadway

A fresh-water swamp dominated by beach hibiscus and a trough of highly disturbed marsh was observed southwest of a recent fill area. The fill area is immediately adjacent to the southwest side of the primary shoreline roadway.

The highly disturbed marsh is situated in the northwest part of the wetland. The marsh is dominated by T-grass and somewhat less amounts of California grass and mauutoga (commelina). Considerably less amounts of weeds, such as Kyllinga nemoralis, tropical cupgrass, Phyllanthus amarus, and three-flowered beggarweed were also evident in the marsh.

All of the plants observed in this area represented introduced plant species. The only native herb recorded during the survey was selesele (Mariscus javanicus) that comprised only a few clumps at the south end of the marsh.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-5 Vegetation Trends

Two known botanical surveys have been made of the Tula wetland during the past 24 years. Whistler made a survey of the Tula wetland in 1976. Biosystems Analysis, Inc. surveyed the area in 1991.

Whistler concluded in 1976 that the area was a former coastal marsh. In 1991, Biosystems Analysis, Inc. later identified the Tula wetland as “...a ruderal freshwater wetland that is predominantly an herbaceous marsh” (Biosystems Analysis, Inc., 1992).

Aerial photographs from 1961 were reviewed by Biosystems Analysis, Inc. to calculate changes in the size of the wetland. Biosystems Analysis concluded that the wetland at Tula was “once dominated by trees and would have been characterized as a freshwater swamp. Much of the area has been cleared but it still supports freshwater herbaceous plants and small, scattered stands of trees and dead snags. The largest stand of trees occupies the upper (western) end of the wetland” (Biosystems Analysis, Inc., 1992).

If the Tula wetland is not further disturbed, the beach hibiscus will probably continue to spread from where it is already established to form a dense thicket. This thicket is expected to exclude all other tree and ground cover species. A similar condition already exists along the vehicular trail that bisects through the west part of the Tula wetland. It is anticipated that the “take over’ by beach hibiscus will be transient and only persist in areas that are disturbed (Steele, 2000).

Should filling of the wetland continue, the Tula wetland will further decrease in size and likely be replaced with homes, as well as banana and taro plantations. PPC has already observed the occurrence of this trend on the east and west sides of the wetland between May 1998 and November 1999.

AQUATIC FISH AND INVERTEBRATES

During the November 2, 1999 survey, only a trickle of water was observed along Vailoa Stream, which is located on the east side of the Tula Wetland. The flow terminated in a pool and apparently seeped into the ground at that point. Despite the lack of stream flow, the stream channel was blocked by larger boulders, debris, and vegetation. Such conditions prevented flow into the Tula wetland, as well as a downstream discharge to the stream mouth and adjoining nearshore waters.

No marcrofaunal species were observed along the Vailoa Stream segment that adjoins the east side of the Tula wetland. This condition was expected since upstream migration of amphidronomous organisms was prevented by the blockage of Vailoa stream. However, one species of chironomid was found in low densities where there was flow.

In American Samoa, each watershed is unique and can be expected to contain different aquatic organisms. The variation depends upon surface water flow regimes, water quality, and other geophysical characteristics. Consequently, if surface flows to the Tula wetland were not impeded along Vailoa Stream, the wetland could possibly include some or all of the type of aquatic animals summarized in Appendix B.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-6 LAND USES IN THE VICINITY OF TULA WETLAND

The Tula wetland has been impacted by land uses within and immediately adjacent to the wetland.

Landfills have been made within the northeast side of the wetland. This area has been filled with a combination of dirt and cinder to facilitate some limited agricultural production, and other structures. Immediately southwest of the fill area, a considerable amount of solid waste material has been dumped within the wetland.

Encroachment on the south, east and west sides of the wetland has also occurred. Landfill and related land use development have primarily established a few residences within the south and east sides of the wetland. Banana plantations and some limited taro production are also located on the south and west sides of the wetland.

A local church is on the east side of the wetland. The congregation has also obtained authorization from the American Samoa Coastal Management Program after constructing a small recreational area on the northwest site of the wetland. In order to gain this authorization, ASCMP required the local church to mitigate their actions through the restoration of other parts of the Tula wetland.

Several piggeries are located along the lower reaches of Vailoa Stream. Some of the piggeries discharge directly into Vailoa Stream and the Tula wetland.

WETLAND RESTORATION AND ENHANCEMENT STRATEGIES

General

There are several potential opportunities for the restoration and enhancement of the Tula wetland. The scope of these six opportunities and related implementation strategies are presented in the following paragraphs.

The potential benefits and impacts derived from the implementation of each strategy are subsequently compared and evaluated. This analysis provides the basis for the selection of a recommended restoration or enhancement strategy.

Preliminary cost estimates are presented for the implementation of the recommended strategy. Long-term monitoring and site maintenance requirements associated with the recommended strategy are also identified.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-7 Alternate Opportunities and Strategies

Option 1: Restore the Southern Part of Tula Wetland

Biosystems Analysis, Inc. suggested in 1992 that the southern portion of the wetland could be restored to the amount of lands contained in the wetland in 1961. The Comprehensive Wetlands Management Plan described the potential scope of the restoration only in terms of general location. Today, a few homes are situated in the southern part of the wetland. Banana plantations adjoin these residences.

The restoration of the southern part of the Tula wetland would require the relocation of several families, residences and related banana plantations to other locations within Tula Village. Subsequently, fill material dumped within the wetland during the past 40 years would need to be excavated and planted with native wetland tree species.

Option 2: Establish a Stormwater Detention Area Within the Wetland

The development of a stormwater detention area within the Tula wetland (Figure 2-3) was recommended by PPC in a Stormwater Management Plan prepared for the Tula wetland and several other sites on the Island of Tutuila.

The aim of the proposed conceptual design was to:

reduce flooding and potential property damage along the west side of Tula Village; direct almost all stormwater flows from the Vailoa Stream drainage into the Tula wetland; detain stormwater flows from stormwater events to permit the settlement of sediments carried by stormwater flows; expand the size of the existing wetland and connect the wetland to the Vailoa Stream drainage; and, use Vailoa Stream as an outlet for stormwater discharges to the nearshore waters.

To accomplish these objectives, PPC proposed the construction of a new earth-lined channel that would be constructed on the west side of Tula Village. A 500-foot long channel would extend from the confluence of Vailoa Stream’s main stem and three tributaries to the Tula wetland. Basaltic rock will be used to line the channel at points where the potential for erosion is likely, e.g., inlets and outlets. Pre-fabricated concrete dissipators would be placed at selected points along the channel to slow the rate of stream discharge.

The existing wetland would be excavated and expanded to include an additional 1.0-acre on the northeast side of the wetland. The expanded wetland would accommodate anticipated 100-year storm discharges. The wetland would be excavated to a depth of approximately three feet above sea level. A nominal slope toward the east side of the wetland will be made to ensure a slower flow of stormwater to an existing culvert (T1) along Vailoa Stream that is situated underneath the primary shoreline roadway.

A three-foot high wall would be constructed along the perimeter of the expanded wetland. The wall would be constructed through the use of small bags of cement that would be hand-carried and placed along the pond perimeter.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-8 Figure 2-3 Option 2: Detention of Stormwater Within Tula Wetland

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-9 The wall would be back-filled with native soil to reduce the visual impact of the concrete bags, as well as afford the opportunity to plant ifi (Tahitian chestnut), other wetland trees, and some fruit trees. Approximately 50 wetland trees and 50 fruit trees would be planted immediately adjacent to the pond perimeter along a 20-foot wide buffer. Wetland and fruit trees would further enhance the attractiveness of the detention area and increase wetland vegetation in the vicinity of the wetland. Planting of the wetland and fruit trees would be the responsibility of the ASCC Land Grant Program.

A culvert would also be installed within the southeast corner of the wall structure to enable the collection and discharge of stream discharges from the existing man-made channel through west side of Tula Village. Existing culvert T1 would serve as the outlet from the detention area where overflows would discharge into the lower end of Vailoa Stream.

Option 3: Expand Taro Production

Another wetland restoration opportunity is to expand taro production within a portion or all of the Tula wetland (Figure 2-4). The expansion of taro production would desirably begin southeast of existing production and gradually expand to the southeast part of the wetland. Water required from taro production would be derived from rainfall, as well as surface water flows from Vailoa Stream.

The portions of the wetland selected for taro production would initially require the excavation of fill material to a minimum soil depth of about one to two feet. Solid waste material and vegetative material contained in the remaining soil material will need to be removed from the site. In terms of soil preparation, the production of talo toto i le vai (wetland taro) will require manual and/or mechanical tilling of the soil and the possible application of some limited nutrients to the soil.

Taro cuttings from disease-free propagating material would be used to establish the taro. The cuttings are part of a taro plant stem about 12 to 18 inches long that is attached to a 2 to 3-inch section of the corm. Such cuttings would ideally be obtained from Western Samoa. Before planting, selected taro cuttings should be carefully inspected, washed with potable water, soaked in a 10 percent bleach solution for 30 seconds, and stored in a dry, cool, and well- ventilated area for 3 to 5 days before planting.

Following larger stormwater events, detained stormwater in the wetland that exceeds what is required for taro production would require a hydrologic connection to Vailoa Stream and the nearshore waters. The restoration of the connection would require the excavation and grading of some fill material and sediments along the bottom of, at least, the southeast side of the wetland to ensure the discharge of surface water to existing culverts below the primary shoreline roadway. Surface flows from Vailoa Stream would also require some clearing of dumped construction and fill materials that impede the discharge of flows into the Tula, as well as the construction of an inlet structure along Vailoa Stream and the southeast side of the wetland.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-10

Figure 2-4 Option 3: Expansion of Taro Production Within Tula Wetland

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-11 Option 4: Plant Wetland Trees to Augment Beach Hibiscus

The Tula wetland could be enhanced through the planting of some wetland trees such as ifi (Tahitian chestnut), falaga, fuafua, and/or afa to augment beach hibiscus. Mango or other fruit trees, e.g., poumuli, could also be planted along the margins of the wetland. Tahitian chestnut would be highly desirable since it is typically a freshwater swamp tree that produces nuts for consumption by both humans and flying foxes.

As stated earlier, vegetative trends suggest that the beach hibiscus will probably continue to spread from where it is already established to form a dense thicket. In the absence of any resource management efforts, this thicket is expected to exclude all other tree and ground cover species. Consequently, the planting of recommended wetland trees would promote the establishment of more wetland vegetation within the wetland.

The tree planting efforts would logically be completed by the ASCC Land Grant Program. Land Grant personnel would need to propagate or obtain wetland tree seedlings and carry out the planting of the seedlings within the wetland. In view of ongoing litigation, it would be prudent for Land Grant Program personnel to exclude local residents from tree planting efforts unless they request the opportunity to participate.

Average rainfall in Tula Village will be adequate to support the growth of the recommended wetland plants. However, the long-term survivability and growth of wetland plants within the Tula wetland will depend upon the availability of fresh and/or brackish water and plant habitat. Re-establishment of a hydrologic connection with Vailoa Stream and the curtailment of further filling of the wetland are required to initiate any serious efforts to promote conservation of wetland plants.

Option 5: Establish Habitat for Aquatic Fish and Invertebrates

Potential opportunities for the re-colonization of aquatic fish and invertebrates may be possible if the Vailoa Stream channel can be cleared of obstructions to restore the former hydrologic connection between Vailoa Stream mouth and the Tula wetland. This wetland enhancement opportunity represents a potential benefit that may be achieved with restoration of the hydrologic connection between the wetland and the Vailoa Stream mouth.

Option 6: Establish a Private Aquaculture Operation

ASCMP and ASEPA representatives suggested to PPC in June 2000 that a small aquaculture operation could be established within a portion of the wetland. This concept would require the establishment of a series of small channels within the wetland where selected fish and/or invertebrate species could be raised and harvested. A technical feasibility study of this option would be required to assess the financial and technical viability of this development concept.

Similar to other potential uses of the wetland, an aquaculture operation would again require the restoration of a hydrologic connection to Vailoa Stream. This connection would require the installation of an inlet structure, i.e., 36-inch diameter culvert, along Vailoa Stream, as well as grading within the southeast part of the wetland to achieve a discharge of stormwater flows to existing culverts underneath the primary shoreline roadway. This connection would be required to avoid the flooding of aquaculture channels and related damage to onsite equipment.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-12 Comparative Benefits and Impacts

PPC’s evaluation of the six alternate restoration and enhancement strategies is summarized in Table 2-2. Three of the six opportunities, Options 2, 3, and 4, would achieve greater benefits to natural resources and enhance opportunities for other potential wetland functions.

Implementation of Option 2 would probably achieve a more desirable range of project benefits. The primary benefits would be increased stormwater detention within Tula Village, increased groundwater recharge, as well as reduction in future flood hazards and property damage. Secondarily, this option would clearly increase wetland vegetation along the margins of the wetland, as well as the two stream channels that would direct surface flows to the wetland. The primary consequence of Option 2 is the significant cost associated with project implementation.

TABLE 2-2 COMPARATIVE EVALUATION WETLAND RESTORATION AND ENHANCEMENT OPPORTUNITIES TULA WETLAND

Option Project Residential Subsistence Fish & Wetland Stormwater Flood Cost Land Uses Agriculture Invertebrate Vegetation Detention Hazards & Habitat Habitat Property Damage 1 SC SC SC NBC SB MB MB 2 SC LC NBC LB MB SB SB 3 MC LC SB LB LB LB MB 4 LC LB LC LB SB LB LB 5 MC LB LC MB LB LB LB 6 MC LC LC LB LB LC LC

Notes: Potential project benefits were rated by PPC as follows: SB Significant project benefits MB Moderate project benefits LB Limited project benefits NBC No anticipated project benefits or undesirable consequences LC Limited undesirable consequences MC Moderate undesirable consequences SC Significant undesirable project impacts

Source: Pedersen Planning Consultants, 2000

Wetland taro production (Option 3) would generate desirable project benefits primarily through the enhancement of subsistence agricultural production. At the same time, the primary use of the wetland for taro production would limit the capacity of the wetland for future stormwater detention.

The planting of wetland trees (Option 4) would enhance the establishment of wetland vegetation within the wetland, but otherwise provide limited project benefits.

Restoration of the south part of the wetland (Option 1) is not a promising opportunity. The relocation of a several households and their residences in this area would not be well received. The American Samoa Government has brought a legal action against a prominent resident of Tula for the alleged fill of the wetland. There is no village rule or other cultural tradition that prohibits the use of land within the Tula wetland (Pulou, 1999). Consequently, any ASG efforts aimed at planting wetland trees in an area presently used for residential purposes would likely be unacceptable to the Tula Village Council and local residents.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-13 The establishment of fish and wildlife habitat (Option 5) provides significant benefits for fish and wildlife habitat with the restoration of a hydrologic connection between the wetland and the mouth of Vailoa Stream. Otherwise, this option provides limited benefits.

Recommended Option and Estimated Project Cost

The development of a stormwater detention area within the Tula wetland, as well as related wetland tree plantings along the wetland margin (Option 2), is recommended for implementation.

While costly, this wetland enhancement project is attractive because the project can achieve multiple benefits to the Tula wetland and Tula Village.

• increase stormwater detention; • reduce flood hazards within the west side of Tula Village; • increase groundwater recharge; • restore and expand wetland vegetation along the wetland margin; and, • establish some fish and invertebrate habitat through restoration of the hydrologic connection between the wetland and Vailoa Stream.

Construction of the proposed earth-lined channel and energy dissipators and detention pond is estimated to cost roughly $339,000 (Table 2-3). The planting of wetland and fruit trees would require an additional $2,571 (Table 2-4). Consequently, the total anticipated project cost would be roughly $341,534.

TABLE 2-3 PRELIMINARY COST ESTIMATE DEVELOPMENT OF CHANNEL AND DETENTION POND IN VAILOA STREAM DRAINAGE AND TULA WETLAND

Item Unit Cost Quantity Extension

Mobilization Lump Sum 1 $ 5,000 Excavation $5/Cubic Yard 5,000 25,000 Channel Construction $50/LF 860 43,000 Berm Construction $100/Linear Foot 1,850 185,000 New Outlets $5,000/Each 3 15,000 Culvert Along Vailoa Stream $325/LF 1 (30 feet) 9,750 Clean Existing Culverts Lump Sum 1 2,000 Road Crossings $5,000/Each 2 10,000 Subtotal $294,750 15% Contingency 44,213

TOTAL $338,963

Source: Pedersen Planning Consultants, 2000

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-14 TABLE 2-4 PRELIMINARY COST ESTIMATE PLANTING OF WETLAND AND FRUIT TREES ALONG TULA WETLAND MARGIN

LABOR Personnel Number Hours Hourly Rate ($) Cost ($) ASCC Plant Nursery Technician 1 104 10 1,040 ASCC Field Crew Leader 1 8 8 64 ASCC Field Crew Members 2 8 6 96 All Personnel 4 120 $1,200

MATERIALS Item Quantity Unit Cost ($) Cost ($) Wetland Trees 50 3 150 Fruit Trees 50 5 250 Garbage Bags 20 boxes 5 100 All Materials $500

EQUIPMENT Shovels 3 22 66 Machetes 3 20 60 Picks 3 15 45 Wheel Barrows 2 50 100 Weed-eaters 2 300 600 All Equipment $871

TOTAL LABOR AND MATERIALS $2,571

Source: Pedersen Planning Consultants, 2000

Long-Term Monitoring and Site Maintenance Requirements

Long-term resource management activities associated with the enhancement and restoration of the Tula wetland should include the seasonal monitoring of selected resource characteristics and periodic site maintenance.

Resource Monitoring

The process of resource monitoring will involve completion of the following steps by ASEPA, ASCMP, or other ASG agency staff:

• Prepare a field map of restoration and enhancement site from available digital files in the American Samoa GIS. • Go to the restoration and enhancement site and collect information summarized on field monitoring worksheet. • Upon return to office from the field, incorporate new spatial data, topographic features, and resource conditions within the American Samoa GIS as points, lines, or polygons. • When desired, expand attribute tables for points, lines and polygons to enhance the description of resource characteristics and changes. • Make an annual evaluation of selected resource conditions that analyzes the effectiveness of the overall restoration and enhancement project.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-15 Long term monitoring of the Tula wetland restoration project will require periodic examinations of:

• changes in stream channel trapezoids; • potential stream modifications; • the benefits derived from restoration of the wetland stormwater detention function; • the survival of new wetland vegetation; and, • changes in adjoining land uses.

The types of information needed, monitoring frequency, monitoring locations, and evaluation parameters are summarized in Table 2-5. A field work sheet or checklist, which can be used in the field, is provided in Table 2-6.

Future resource monitoring can be effectively performed through bi-annual site visits to the Tula wetland and related stream channels. This approach will enable comparisons during wet (December through March) and dry (April through November) seasons of the year. Additional visits should also take place during and/or following significant stormwater events that may be generated from periods of significant rainfall.

The availability of the American Samoa geographical information system enables the incorporation of most all resource monitoring information within the GIS. Field data can be summarized in attribute tables or databases. Digital photos can be linked to digital maps of the restoration site.

Recommended monitoring stations or sites (Figure 2-5) should be used consistently unless unanticipated events, new land uses, or access issues prevent continued use. When necessary, changes in the location of monitoring stations should be documented and spatially located within the American Samoa GIS. PPC has provided digital files for the Wetland and Stream Restoration and Enhancement Plan that provide a departure point for future resource monitoring in the vicinity of the Tula wetland.

Digital photos should also be dated and subsequently incorporated into the digital photo album for the Tula wetland. This will enable a long-term comparison of resource information by ASG staff and consultants that may be used to perform long-term resource monitoring.

Vehicular and pedestrian access to selected monitoring stations is largely dependent upon the cooperation and authorization of local residents. Traditional leaders of the Tula Village Council should be contacted before any long-term monitoring activities are initiated and carried out.

Site Maintenance

Periodic site maintenance should take place within the Tula wetland, lower Vailoa Stream, and the proposed stream channel approximately four times per year. Human disposal of solid wastes within the wetland and the two stream channels is expected to represent the primary focus of long-term site maintenance.

A crew of three to four persons will be necessary to walk the length of the two stream channels within the inhabited village area. Through the use of machetes and weed-eaters, the slopes of both earth-lined channels will require the periodic trimming of vegetation along selected portions of the stream channels. The collection of solid wastes will also be necessary to minimize obstructions to stream flow and potential reductions in channel capacity.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-16 TABLE 2-5 LONG-TERM RESOURCE MONITORING REQUIREMENTS AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN TULA WETLAND

Resource Information Monitoring Monitoring Monitoring Evaluation Requirement Frequency Method Location(s) Parameters Wetland/Stream Stream Flow 1 x (Dec-March) Visual observation Vailoa Stream: 700 feet upstream of wetland Presence of stream flow or obstructions to storm flow Hydrology 1 x (April-Nov) Visual observation New channel: 400 feet upstream of wetland Wetland Outlet 1 x (Dec-March) Visual observation New outlet that will discharge into lower Presence of discharge from wetland into lower 1 x (April-Nov) Visual observation Vailoa Stream Vailoa Stream Stream Channel Stream channel 1 x (Dec-March) Measure manually, using tape measure Vailoa Stream: 700 feet upstream of wetland Changes in dimensions of stream channel trapezoid cross sections 1 x (April-Nov) at 100-foot intervals New channel: 400 feet upstream of wetland at 100-foot intervals Stream Modifications Changes to 1 x (Dec-March) Take digital photos, measure manually Vailoa Stream: 700 feet upstream of wetland Evidence of bank erosion, changes in flow path, or new stream banks 1 x (April-Nov) using tape measure, record type & size, New channel: 400 feet upstream of wetland manmade structures along stream bank (e.g., rock walls) locate changes on map, incorporate data into GIS Water Quality Changes in land 1 x (Dec-March) Take digital photos, document type and Within 100 feet of wetland perimeter as well as Do new land uses generate non-point surface or subsurface uses 1 x (April-Nov) estimated size, locate changes on map, within 100 feet of Vailoa Stream and new discharges into wetland or stream channels? incorporate data into GIS stream channels Stormwater Restoration of 1 x (Dec-March) Take digital photos New water level post Water depth, in feet Detention Area stormwater 1 x (April-Nov) Document depth of water detention detention function Vegetation Survival of new 1 x (Dec-March) Take visual count of new plants 10 random stations around wetland perimeter Number of plants that remain vegetation 1 x (April-Nov) TABLE 2-6 FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN TULA WETLAND PAGE 1 OF 2 PAGES Date(s) of field monitoring:______Name(s) of observer(s): Agency/Company Represented:

Vailoa Stream New Channel STREAM AND WETLAND HYDROLOGY (Circle "yes" or "no".) 1 Is water flowing in the stream? Yes No Yes No 2a Are stream flows entering the wetland? Yes No Yes No b If no, what appears to be impeding stream discharge? Describe. 3 a Is the wetland outlet, e.g., culvert or stream mouth, clear to permit stream discharge? Yes No Yes No b If not, what appears to be impeding flow to the wetland outlet? Describe. 4 Observe and record water level post in wetland. feet

STREAM CHANNEL MODIFICATIONS 5 a Has the stream bank been altered and with what material has the alteration been made? Yes No Yes No ___ Basaltic rock wall ___ Concrete wall ___ Rock-filled gabions ___ Other, please describe: b If alteration has occurred, locate on field map _____ Check, when field map is so marked. 6 a Do existing rock walls, concrete walls or gabions appear to have been damaged from past or recent stormwater events? Yes No Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 7 a Is there evidence of bank erosion? Yes No Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 8 a Do you see evidence of a change in the stream flow path? Yes No Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked

CHANGES IN STREAM CHANNEL TRAPEZOID 9 Refer to page 2: For each trapezoid represented, measure the distances between 1) Points A and B, 2) Points C and D, and 3) Points E and F. Write in the measurement on each trapezoid.

SURVIVAL OF NEW WETLAND PLANTS 10 a Count number of surviving new wetland trees b Count number of surviving new fruit trees

CHANGES IN LAND USE 11 a Document type and number of new land uses within 100 feet of stream channels and wetland perimeters Number of facilities: Briefly describe each new facility: Residential Commercial Industrial Public Facility Community Facility Agricultural b Map location of new land uses on field map. ___ Check, when field map is so marked 12 a Do any existing land uses, within 100 feet of the stream channel or wetland perimeter, appear to have sustained damage from past or recent stormwater events? Yes No Yes No b If so, where? (Locate on field map.) ___ Check, when field map is so marked

NON-POINT DISCHARGES INTO STREAM CHANNELS OR WETLAND 13 Type of discharges: Briefly describe type of discharge: Piggery Stormwater Cesspool Industrial Commercial 14 Locate discharge on field map ___ Check, when field map is so marked TABLE 2-6 (CONTINUED) FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN TULA WETLAND CHANGES IN STREAM CHANNEL TRAPEZOID PAGE 2 OF 2 PAGES 9 For each trapezoid represented below, measure the distances between 1) Points A and B, 2) Points C and D, and 3) Points E and F. Write in the measurement on each trapezoid.

Station Vailoa Stream New Channel

1+ 00 E E ABAB

C D C D FF

2 + 00 E E ABAB

C D C D FF

3 + 00 E E ABAB

C D C D FF

4 + 00 E E ABAB

C D C D FF

5 + 00 E AB

C D F

6 + 00 E AB

C D F

7 + 00 E AB

C D F FIGURE 2-5 RESOURCE MONITORING STATIONS AND AREAS TULA WETLAND

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Tula Wetland, Page 2-20 Chapter Three ALAO WETLAND

LOCATION

Alao Village is located along the southeast coast of the Island of Tutuila and immediately south of Tula. There are two wetlands in Alao. The fresh-water wetland on the west side of Alao Village, or the smaller “Taufusi Marsh”, was evaluated for the Wetland Restoration and Enhancement Plan (Figure 3-1). Past studies suggest that the smaller Taufusi Marsh comprises approximately 5.6 acres of land area (Biosystems Analysis, 1992).

WETLAND HYDROLOGY

Sources of Surface Runoff to the Taufusi Marsh

Surface runoff from Mulivaitele Stream drains into the Taufusi Marsh. The Mulivaitele Stream drainage also includes surface runoff from Vaifusi Stream and Vaialili, which are tributaries to Mulivaitele Stream. PPC confirmed these surface flow inputs to the Taufusi Marsh via onsite observations in November 1999. PPC also contacted a traditional village leader and another local resident who provided valuable information concerning past and recent hydrologic conditions.

From the wetland, the main channel of Mulivaitele Stream serves as an outlet for the Taufusi Marsh. Stormwater flows are carried to a shoreline discharge point east of the primary shoreline roadway (Figure 3-2). In November 1999, PPC observed no obstructions to stream flow. Signs of recent, continuous surface flow to the nearshore waters were also evident.

Stream Flows Along Mulivaitele Stream

Median Stream Flows

In 1996, the U.S. Geological Survey published estimated median stream flows from Vaialili Stream and Vaifusi Stream. These estimates were based upon measurements gained from, two low-flow, partial-record stations between 1958 and 1976, as well as related hydraulic modeling.

One station along Vaialili Stream (No. 16965000) was situated approximately 0.2 mile upstream from the confluence with Vaifusi Stream. Data from 18 measurements enabled the U.S. Geological Survey to estimate a median flow of 0.08 cubic feet per second (cfs).

A second station along Vaifusi Stream (No. 16966000), about 400 feet upstream of the stream mouth, provided 17 measurements between 1958 and 1975. Data gained from these measurements led the U.S. Geological Survey to estimate a median flow of 0.02 cfs (Wong, 1996).

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-1 Figure 3-1 Location Map Alao Village Wetland

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-2 Figure 3-2 Taufusi March Existing Conditions

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-3 Stormwater Discharges and Related Flood Potential

Pedersen Planning Consultants made a hydrologic analysis of Mulivaitele Stream to determine the potential amount of stormwater that could be discharged into the Taufusi Marsh via a range of stormwater events (Table 3-1).

TABLE 3-1 POTENTIAL STORMWATER DISCHARGES INTO TAUFUSI MARSH FROM MULIVAITELE STREAM AND ITS TRIBUTARIES 2,10,50, AND 100-YEAR STORM EVENTS IN CUBIC FEET PER SECOND (CFS)

Location 2-Year Storm 10-Year Storm 50-Year Storm 100-Year Storm Mulivaitele Stream and all tributaries 238 393 701 813

Source: Pedersen Planning Consultants, 2000

Through hydrologic modeling, PPC determined that potential stormwater discharges along Mulivaitele stream can range from 238 cubic feet per second (cfs) for a 2-year storm and about 813 cfs for a 100-year storm.

During its November 1999 survey of the Taufusi Marsh, long-term residents informed the PPC survey team indicated that the village had previously experienced occasional flooding along the stream channel that serves as a hydrologic outlet from the wetland marsh to the nearshore waters (Figure 3-2). However, the clearing of some obstructions within the Mulivaitele Stream channel, which was accomplished by the American Samoa Power Authority in 1990, resolved local flooding problems associated with smaller stormwater events, e.g., 2-year storm (Puaauli, 1999).

The potential flood plain associated with a 100-year storm event in Alao was mapped by the Federal Emergency Management Agency (FEMA) in May 1991. When this information is correlated with digital building location data from the American Samoa GIS, it is clear that a 100-year flood event would clearly impact most of the inhabited village area (Figure 3-3).

Given these prospects, it is important to conserve the Taufusi Marsh to promote continued opportunities for stormwater detention. Otherwise, Alao Village may become more susceptible to potential flood damages to residential and commercial property.

WETLAND VEGETATION

November, 1999 Survey

Art Whistler of Isle Botanica conducted a botanical survey of the Taufusi Marsh on November 2, 1999. Mr. Whistler was part of a three-person field survey team organized by Pedersen Planning Consultants that observed wetland vegetation, habitat for aquatic fish and invertebrates, stream hydrology, as well as land uses within and adjacent to the wetland. His observations are summarized in the following paragraphs.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-4 Figure 3-3 FEMA 100-Year Flood Plain Alao Village

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-5 East Portion of the Marsh

The east portion of Taufusi Marsh was recently cleared of vegetation for the continued production of Chinese cabbage. A network of man-made ditches and smaller cultivated plots were constructed within this area to facilitate drainage.

Immediately inland of this cleared area was a moderate-sized area devoted to the production of bananas. A few older papaya trees and coconut trees were also observed in this area; however, they were not planted for any commercial production.

West Portion of the Marsh

The west portion of Taufusi Marsh appeared to be an abandoned taro patch that was dominated by a dense herbaceous cover of mauutoga (Commelina diffusa or commelina). This portion of the marsh also contained considerably less amounts of primrose willow, fue sina (beach pea), and fue saina (mile-a-minute vine). Other typical herbaceous wetland plants included sansana (Job’s tears), fanamanu (Indian shot), Hibiscus abelmoschus, and Luffa cylindrica along with scattered and overgrown individuals of talo (taro) that mauutoga (Commelina diffusa) have survived neglect.

The west end of the marsh was also characterized by some patches and scattered individuals of the shrubby laau failafa (candelabra plant) and some smaller fau (beach hibiscus) trees. Along the wetland margin, typical upland weeds such as Operculina turpethum, graceful spurge, and beggar’s-tick replaced wetland vegetation. California grass, which is often common in wetlands, was also present.

Vegetation Trends

Between 1962 and 1964, several families in Alao planted talo (taro) in the Taufusi Marsh. Taro production in Taufusi Marsh continued until 1998. Families began harvesting poor taro crops in the mid-1990’s as a result of lega (taro leaf blight) that adversely affected taro production in Alao and other production areas in American Samoa.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-6 East Portion of the Marsh

The impact of the taro leaf blight led some families, who had title to communal lands in the Marsh, to begin production of Chinese cabbage in the east portion of the marsh. This crop is now sold at the Fagatogo marketplace (Puaauli, 1999). Once the new blight-resistant cultivars of taro become more readily available, taro production may once again be established within, at least, the east portion of the Marsh.

West Portion of the Marsh

In 1992, Biosystems Analysis, Inc. observed taro cultivation along with willow primrose in the Taufusi marsh. It was also noted that soils in Taufusi Marsh “....drain slowly enough to support wetland plants”. With the more recent discontinuation of taro production, the west portion of the wetland transitioned to a disturbed marsh.

It is likely that the west portion of the marsh will continue to be dominated by commelina. However, if the smaller hibiscus patches at the west end of the marsh continue to spread, the fau (Hibiscus tiliaceus) could possibly shade out the marsh vegetation and create a fresh-water marsh dominated by fau (beach hibiscus).

AQUATIC FISH AND INVERTEBRATES

General

On November 2, 1999, Charles Chong of the PPC field survey team made observations of aquatic fish and invertebrates along a segment of Mulivaitele Stream from the east side of Taufusi Marsh to approximately 380 feet upstream of the Mulivaitele Stream mouth. His observations are summarized in the following paragraphs.

The stream did not exhibit a stream discharge into the nearshore waters during the field survey. However, a nominal flow of less than 0.5 cubic feet per second (cfs) flowed downstream to a point that was about 380 feet upstream of the shoreline. At this point, stream flows percolated into the bottom of the stream channel.

Mulivaitele Stream Segment Along East Side of Marsh

The fish and invertebrate survey focused upon the segment of the Mulivaitele Stream channel between the east side of Taufusi Marsh to approximately 380 feet upstream of the stream mouth. The bed of the stream channel was characterized by cobble on top of clay soil. There was moderately heavy canopy above the stream. However, there was little or no periphyton along this stream segment.

The stream fauna contained an abundance of the fresh-water shrimp Macrobrachium lar that is known to be amphidromous. Kuhlia rupestris was also abundant in larger pools. No gobies or anguillids were observed, although they have may have been present further upstream.

Non-amphidromous species included the same chironoid larvae found in the Alao wetland. Many types of damselflies and dragonflies were also documented.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-7 In American Samoa, each watershed is unique and can be expected to contain different aquatic organisms. The variation depends upon surface water flow regimes, water quality, and other geophysical characteristics. With perennial, unimpeded stream flow to the ocean, the wetland could possibly include some or all of the type of aquatic animals summarized in Appendix B.

Relative Abundance and Diversity of Fish and Invertebrates

A site specific summary of macrofaunal organisms observed during the survey is summarized in Table 3-2. Genera are listed in order of descending abundance within their taxonomic group.

TABLE 3-2 SUMMARY OF MACROFAUNAL ORGANISMS OBSERVED ALONG MULIVAITELE STREAM

Stream Location Fishes Crustaceans Molluscs

From the east side of Taufusi Marsh Kuhlia Macrobrachium None to approximately 380 feet upstream (2 spp.) of stream mouth.

Source: Chong, 2000

The relative abundance and diversity of fish and invertebrates in Mulivaitele Stream, along the east side of Taufusi Marsh, is summarized in Table 3-3. The relative abundance and diversity reflects a general comparison of the abundance and diversity of fish and invertebrates observed along Mulivaitele Stream with all 10 sites evaluated for the Wetland Restoration and Enhancement Plan.

TABLE 3-3 RELATIVE ABUNDANCE AND DIVERSITY OF FISH AND INVERTEBRATES MULIVAITELE STREAM SEGMENT ON EAST SIDE OF TAUFUSI MARSH

Fishes Crustaceans Molluscs Abundance Medium High Low Diversity Low Low Low

Source: Pedersen Planning Consultants, 2000

LAND USES IN THE VICINITY OF TAUFUSI MARSH

As stated earlier, some production of Chinese cabbage was found in the east portion of the Taufusi Marsh. Other than a small shed, no other land uses were present in the marsh.

The inhabited portion of Alao Village lies primarily east of Mulivai Stream. Only two to three residences are within about 500 feet of the marsh. Some limited subsistence banana production, as well as a relatively large greenhouse used for cucumber production, were situated immediately east of Mulivai Stream and the southeast side of Taufusi Marsh.

Other areas that adjoin the north, south and west sides of the marsh remain undeveloped.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-8 WETLAND RESTORATION AND ENHANCEMENT STRATEGIES

General

There are two potential opportunities for the restoration and enhancement of Taufusi Marsh. The scope of these two opportunities and related implementation strategies are presented in the following paragraphs.

Alternate Opportunities and Strategies

Option 1: Restore Native Marsh Vegetation and Wildlife Habitat

This option would attempt to restore native marsh vegetation in portions of the west part of the Taufusi Marsh. This restoration effort would be made through the planting of native marsh plants such as utuutu (water chestnut), vao tuaniu (marsh fern), and saato (swamp fern). Plantings of seedlings or cuttings would be obtained by the ASCC Land Grant program and planted by program personnel in selected portions of west Taufusi Marsh. However, it should be noted that the feasibility of this option has not been tested through the propagation of these plants in American Samoa or other parts of Polynesia (Whistler, 2000)

Soil preparation will likely include the clearing and/or excavation of some areas where dense exotic vegetation is already established. Plant spacing and density would be determined by the ASCC Land Grant Program prior to the initiation of planting.

None of the recommended marsh plants were found in the marsh in November 1999 and probably do not exist there. However, the establishment of these native marsh plants would enhance the attractiveness of this marsh to the toloa (Australian Gray Duck). This duck is widespread in the South Pacific, but very rare in American Samoa. The habitat of the Australian Gray Duck is typically fresh-water wetlands, but the duck is occasionally found in brackish or salt water (Engbring and Ramsey, 1989). Occasional sightings of the Australian Gray Duck have been documented in the vicinity of nearby Maliuga Point (Aecos and Aquatic Farms, 1980).

Option 2: Restore Taro Production

Option 2 (Figure 3-4) would restore taro production within the west portion of Taufusi Marsh. This potential restoration project would somewhat increase the capability of the marsh to detain storm water. Increased detention would also promote greater recharge of surface runoff into the basal aquifer.

ASPA operates one groundwater well (well 161) and a related satellite water system in Alao. Well 161 produced approximately 12,000 gallons per day in May 2000. Consequently, the potential benefits of increased groundwater recharge provide a feasible opportunity to conserve potable water supplies in Alao.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-9 FIGURE 3-4 OPTION TWO: RESTORE TARO PRODUCTION

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-10 The availability of new, blight-resistant cultivars of taro could enable future taro production in the Taufusi Marsh. A project manager from the American Samoa Coastal Management Program (ASCMP) would need to coordinate project tasks in cooperation with the American Samoa Department of Agriculture and/or the Ministry of Agriculture in Western Samoa to obtain new varieties of taro that are resistant to the lega (taro blight).

When obtained, a sample of such plants would be provided by the American Samoa CMP to representatives of families holding titles to lands within the marsh. The intent of this approach would be to:

• encourage family efforts to re-establish new varieties of wetland taro within the marsh, and • enable Alao residents to test the interest of Tutuila residents to purchase and consume these new varieties of taro.

Implementation of this project would initially require the excavation of fill material in the west portion of Taufusi Marsh to a minimum soil depth of about one to two feet. Solid waste material and vegetative material contained in the remaining soil material will need to be removed from the site. In terms of soil preparation, the production of talo toto i le vai (wetland taro) will require manual and/or mechanical tilling of the soil and the possible application of some limited nutrients to the soil.

Taro cuttings from disease-free propagating material would be used to establish the taro. The cuttings are part of a taro plant stem about 12 to 18 inches long that is attached to a 2 to 3-inch section of the corm. Such cuttings would ideally be obtained from the ASG Department of Agriculture or Samoa Ministry of Agriculture in Apia. Before planting, selected taro cuttings would be carefully inspected, washed with potable water, soaked in a 10 percent bleach solution for 30 seconds, and stored in a dry, cool, and well-ventilated area for 3 to 5 days before planting.

Comparative Benefits and Impacts

PPC’s evaluation of two alternate restoration and enhancement strategies is summarized in Table 3-4. One of these opportunities, Options 2, would achieve greater benefits to natural resources and enhance opportunities for other potential wetland functions.

An attempt to restore native marsh vegetation (Option 1) would require the planting of native marsh plants such as utuutu (water chestnut), vao tuaniu (marsh fern), and saato (swamp fern). None of these marsh plants were found in the marsh in November 1999 and probably do not exist there. However, cuttings could be obtained by the ASCC Land Grant Program and planted by program staff.

The prospect of community support for this restoration opportunity may be limited. At least four families in Alao Village hold titles to the lands comprising Taufusi Marsh (Puaauli, 2000). One or more families continue to be using the east portion of the wetland for the commercial production of Chinese cabbage that generates some household income.

Wetland taro production would generate more desirable project benefits. Taro production would primarily enhance subsistence and commercial agricultural production, which is consistent with other ongoing uses of the wetland. At the same time, taro production would secondarily enhance future stormwater detention and generate some increased groundwater recharge to the basal aquifer.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-11 TABLE 3-4 COMPARATIVE EVALUATION WETLAND RESTORATION AND ENHANCEMENT OPPORTUNITIES ALAO WETLAND

Option Project Residential Subsistence Wildlife Wetland Stormwater Flood Cost Land Uses Agriculture Habitat Vegetation Detention Hazards & Habitat Property Damage 1 LC NBC NBC SB SB LB NBC 2 LC NBC SB LB LB MB LB Notes: Potential project benefits were rated by PPC as follows: SB Significant project benefits LC Limited undesirable consequences MB Moderate project benefits MC Moderate undesirable consequences LB Limited project benefits SC Significant undesirable project impacts NBC No anticipated project benefits or undesirable consequences

Source: Pedersen Planning Consultants, 2000

Recommended Option and Estimated Project Cost

The restoration of taro production within the Taufusi Marsh (Option 2) is recommended for implementation. This wetland enhancement project is recommended because the project can be achieved cost effectively, and at the same time, provide multiple benefits to Taufusi Marsh and Alao Village.

From a resource management perspective, taro production will provide a combination of benefits that can be derived from increased stormwater detention and increased groundwater recharge. Alao Village may gain some nominal economic benefits from taro production that could generate some local employment and help sustain the economic viability of the community. The restoration of taro production is complementary to other commercial agriculture production within the east side of the marsh.

The costs associated with the restoration of taro production would be limited to the purchase of wetland taro cuttings and the distribution of taro cuttings to Alao Village (Table 3-5). Otherwise, labor and equipment required for taro planting would be provided by local residents of Alao. Total project costs are estimated to be $1,640.

TABLE 3-5 PRELIMINARY COST ESTIMATE PROCUREMENT AND DISTRIBUTION OF TARO PLANT CUTTINGS TO ALAO VILLAGE

LABOR Personnel Number Hours Hourly Rate ($) Cost ($) ASCC Plant Nursery Technician 1 104 10 1,040 All Personnel 1 104 $1,040 MATERIALS Item Quantity Unit Cost ($) Cost ($) Taro Cuttings 100 5 500 Garbage Bags 20 boxes 5 100 All Materials $600 EQUIPMENT (to be supplied by Alao Village) All Equipment $0 TOTAL LABOR AND MATERIALS $1,640

Source: Pedersen Planning Consultants, 2000

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-12 Long-Term Monitoring and Site Maintenance Requirements

Long-term resource management activities associated with the enhancement and restoration of the Alao wetland should include the seasonal monitoring of selected resource characteristics and periodic site maintenance.

Resource Monitoring

The process of resource monitoring will involve completion of the following steps by ASEPA, ASCMP, or other ASG agency staff:

Long term monitoring of the Alao wetland restoration and enhancement project will require periodic examinations of:

• changes in stream channel trapezoids between the wetland and the Mulivaitele Stream mouth; • potential stream modifications; • the survival of new taro plantings and taro production yields; • changes in adjoining land uses; and, • potential non-point source discharges into the wetland.

The types of information needed, monitoring frequency, monitoring locations, and evaluation parameters are summarized in Table 3-6. A field work sheet or checklist, which can be used in the field, is provided in Table 3-7.

Future resource monitoring can be effectively performed through bi-annual site visits to the Alao wetland and lower Mulivaitele Stream channel. This approach will enable comparisons during wet (December through March) and dry (April through November) seasons of the year.

Additional visits should also take place during and/or following significant stormwater events that may be generated from periods of significant rainfall.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-13 TABLE 3-6 LONG-TERM RESOURCE MONITORING REQUIREMENTS AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN ALAO WETLAND

Stream Changes to 1 x (Dec-March) Take digital photos, measure manually Mulivaitele Stream: 1000 feet downstream of Evidence of bank erosion, changes in flow path, or new Modifications stream banks 1 x (April-Nov) using tape measure, record type & size, wetland manmade structures along stream bank (e.g., rock walls) locate changes on map, incorporate data into GIS Vegetation Survival of new 1 x (Dec-March) Take visual count of new taro plants Where taro plantings are made Number of taro plants that remain; production yields taro plants 1 x (April-Nov) Water Quality Changes in land 1 x (Dec-March) Take digital photos, document type and Within 100 feet of wetland perimeter as well as Do new land uses generate non-point surface or subsurface uses 1 x (April-Nov) estimated size, locate changes on map, within 100 feet of Mulivaitele Stream discharges into wetland or Mulivaitele Stream channels? incorporate data into GIS TABLE 3-7 FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN ALAO WETLAND PAGE 1 OF 2 PAGES Date(s) of field monitoring:______Name(s) of observer(s): Agency/Company Represented: Mulivaitele Mulivaitele Stream Stream STREAM AND WETLAND HYDROLOGY (Circle "yes" or "no".) 1 Is water flowing in the stream? Yes No Yes No 2a Are stream flows entering the wetland? Yes No Yes No b If no, what appears to be impeding stream discharge? Describe. 3 a Is the wetland outlet, e.g., culvert or stream mouth, clear to permit stream discharge? Yes No Yes No b If not, what appears to be impeding flow to the wetland outlet? Describe.

STREAM CHANNEL MODIFICATIONS 4 Has the stream bank been altered and with what material has the alteration been made? Yes No Yes No ___ Basaltic rock wall ___ Concrete wall ___ Rock-filled gabions ___ Other, please describe: 5 If alteration has occurred, locate on field map _____ Check, when field map is so marked. 6 a Do existing rock walls, concrete walls or gabions appear to have been damaged from past or recent stormwater events? Yes No Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 7 a Is there evidence of bank erosion? Yes No Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 8 a Do you see evidence of a change in the stream flow path? Yes No Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked

SURVIVAL OF NEW WETLAND PLANTS 10 a Count number of surviving new taro plants b Ask local resident to estimate annual production yield. Pounds

CHANGES IN LAND USE 11 a Document type and number of new land uses within 100 feet of stream channel and wetland perimeter Number of facilities: Briefly describe each new facility: Residential Commercial Industrial Public Facility Community Facility Agricultural b Map location of new land uses on field map. ___ Check, when field map is so marked 12 a Do any existing land uses, within 100 feet of the stream channel or wetland perimeter, appear to have sustained damage from past or recent stormwater events? Yes No Yes No b If so, where? (Locate on field map.) ___ Check, when field map is so marked

NON-POINT DISCHARGES INTO STREAM CHANNEL OR WETLAND Z Type of discharges: Briefly describe type of discharge: Piggery Stormwater Cesspool Industrial Commercial 14 Locate discharge on field map ___ Check, when field map is so marked TABLE 3-7 FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN ALAO WETLAND PAGE 1 OF 2 PAGES Date(s) of field monitoring:______Name(s) of observer(s): Agency/Company Represented: Mulivaitele Mulivaitele Stream Stream STREAM AND WETLAND HYDROLOGY (Circle "yes" or "no".) 1 Is water flowing in the stream? Yes No Yes No 2a Are stream flows entering the wetland? Yes No Yes No b If no, what appears to be impeding stream discharge? Describe. 3 a Is the wetland outlet, e.g., culvert or stream mouth, clear to permit stream discharge? Yes No Yes No b If not, what appears to be impeding flow to the wetland outlet? Describe.

SURVIVAL OF NEW WETLAND PLANTS 10 a Count number of surviving new taro plants b Ask local resident to estimate annual production yield. Pounds

NON-POINT DISCHARGES INTO STREAM CHANNEL OR WETLAND Z Type of discharges: Briefly describe type of discharge: Piggery Stormwater Cesspool Industrial Commercial 14 Locate discharge on field map ___ Check, when field map is so marked Recommended monitoring stations or sites should be used consistently unless unanticipated events, new land uses, or access issues prevent continued use. When necessary, changes in the location of monitoring stations should be documented and spatially located within the American Samoa GIS. PPC has provided digital files for the Wetland and Stream Restoration and Enhancement Plan that provide a departure point for future resource monitoring in the vicinity of the Alao wetland.

Digital photos should also be dated and subsequently incorporated into the digital photo album for the Alao fresh-water wetland. This will enable a long-term comparison of resource information by ASG staff and consultants that may be used to perform long-term resource monitoring.

Digital photos of taro production should also be supplemented with documentation of actual production yields from local residents. This information should be documented within a computer spreadsheet that would be established for production data. This information would facilitate future evaluations of taro production.

Vehicular and pedestrian access to selected monitoring stations is largely dependent upon the cooperation and authorization of local residents. Traditional leaders of the Alao Village Council should be contacted before any long-term monitoring activities are initiated and carried out.

Site Maintenance

Periodic site maintenance should take place within the Alao fresh-water wetland and lower Mulivaitele Stream approximately four times per year. Human disposal of solid wastes within the wetland and the Mulivaitele Stream channel is expected to represent the primary focus of long-term site maintenance.

A crew of three to four persons will be necessary to walk the length of the lower Mulivaitele Stream channel within the inhabited village area. Through the use of machetes and weed- eaters, the portions of the Mulivaitele Stream channel will require the periodic trimming of vegetation. The collection of solid wastes will also be necessary to minimize obstructions to stream flow and potential reductions in channel capacity.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Alao Wetland, Page 3-17 Chapter Four AOA WETLAND

LOCATION

Aoa Village is located along the northeast coast of the Island of Tutuila. There is one large wetland in Aoa that comprises roughly 23.5 acres of land area (Figure 4-1). The Aoa wetland includes a combination of fresh-water swamp, fresh-water marsh, and swamp forest.

WETLAND HYDROLOGY

Sources of Surface Runoff to the Aoa Wetland

The primary source of water in the wetland is surface runoff from Tapua Stream and Puna Stream (Figure 4-2). Tapua Stream receives drainage from its upland tributary, Lepa Stream, and generally flows south to north through the middle of the wetland before discharging into the nearshore waters. Puna Stream, which originates near the 400-foot contour, transports runoff from the west side of Olomoana Mountain through the northeast side of the wetland.

Available topographic maps for Aoa Village suggest a contribution of runoff from Vaitolu Stream to the Aoa wetland. Field observations by PPC in November 1999 indicate that the lower channel may have been modified by local residents to:

• help reduce potential flood damages to residential property; and/or, • accommodate past residential development on the southwest side of the wetland.

Stream flows presently discharge directly to Aoa Bay in the Vaiaga area. PPC believes that Vaitolu Stream may have formerly discharged into Aoa wetland.

A smaller portion of the runoff discharged into the wetland is also received directly from via steeper, upland slopes on the south side of the wetland.

Stream Flows

Median Stream Flows

In 1996, the U.S. Geological Survey published an estimated median stream flow for Lepa Stream (Figure 4-1). The median stream flow estimate was based upon historical stream flow measurements obtained from a low-flow, partial-record station between 1958 and 1975, as well as related hydraulic modeling (Table 4-1).

TABLE 4-1 MEDIAN STREAM FLOW ESTIMATE LEPA STREAM

Stream USGS Gage Location Stream Flow Estimated Gage Station Measure-ments Median Flow (number) (cfs) Lepa Stream 16905000 0.5 mile upstream from 22 0.11 Tapua Stream mouth

Source: Wong, 1996

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-1 Figure 4-1 Location Map Aoa Village Wetland

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-2 Figure 4-2 Aoa Wetland Existing Conditions

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-3 No stream flow estimates are available for Puna Stream. However, former Aoa resident and principal of Olomoana Elementary School informed Pedersen Planning Consultants in 1996 that Puna Stream flows intermittently. PPC found no evidence of stream flow during the November 1999 survey.

Stormwater Discharges and Related Flood Potential

Pedersen Planning Consultants made a hydrologic analysis of the potential stormwater discharges to Aoa wetland during a range of storm events.

TABLE 4-2 POTENTIAL STORMWATER DISCHARGES INTO AOA WETLAND FROM TAPUA AND PUNA STREAMS 2,10,50, AND 100-YEAR STORM EVENTS IN CUBIC FEET PER SECOND (CFS)

Location 2-Year Storm 10-Year Storm 50-Year Storm 100-Year Storm Tapua-Lepa Stream Drainage 455 725 1,228 1,392

Puna Stream 55 95 180 215

All Streams 510 820 1,408 1,607

Source: Pedersen Planning Consultants, 2000

Through hydrologic modeling, PPC determined that potential stormwater discharges into the Aoa wetland can range from 510 cubic feet per second (cfs) for a 2-year storm and about 1,607 cfs for a 100-year storm.

During PPC’s November 1999 survey, a 17-year resident of Aoa informed the survey team that about four homes on the southeast side of the wetland are flooded about once a year. Moist soil and water typically enter this area during the rainy season (Afusia, 1999). PPC representatives observed similar flooding and moist soil conditions during its survey of the village in May 1996 for the American Samoa Watershed Protection Plan.

The potential flood plain associated with a 100-year storm event in Aoa was mapped by the Federal Emergency Management Agency (FEMA) in May 1991. Available flood insurance rate maps prepared by FEMA suggest that all inland village areas south of the Aoa Bay shoreline have limited flood potential.

However, continued landfill in the southeast part of the Aoa wetland for residential purposes will only decrease the capability of the wetland to detain stormwater. Future residential expansion will likely exacerbate flooding problems and generate more future property damages in the southeast part of the wetland. PPC representatives discussed this issue with the village pulenuu, who is also a matai, during the November 1999 survey. The matai/pulenuu indicated that he would discuss the flooding problems and future stormwater detention needs with other members of the Aoa Village council (Taase, 1999).

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-4 Hydrologic Outlet to Aoa Bay

The mouths of Tapua Stream and Puna Stream represent the hydrologic outlets to the Aoa wetland. Two sets of culverts are situated below a shoreline vehicular trail on the northeast side of Olomoana School.

A set of two 12-foot wide x 5-foot high culverts are located immediately adjacent to the northeast side of Olomoana Elementary School. These culverts were apparently constructed to accommodate drainage from Tapua Stream. Roughly 100 feet east of these culverts lies an older and smaller 12-foot wide x 3.5-foot high culvert that should accommodate flows from Puna Stream. This culvert probably carried the combined drainage from Puna and Tapua Stream before construction of the two newer culverts.

In November 1999, Pedersen Planning Consultants (PPC) observed that surface flows from the wetland to the newer culverts were completely clear and a nominal stream flow of less than 0.5 cfs was evident. In contrast, potential stream flow through the older culvert was blocked by debris, vegetation, and sand on the seaward side of this outlet.

During the survey of the Aoa wetland, PPC’s three-person field survey team was accompanied by Mr. Colin Steele, ASCC/AHNR project forester. Mr. Steele observed during the survey that the blockage of one of the two sets of culverts and related loss of tidal exchange had impacted the health of mangrove plants on the northeast side of the Tapua Stream mouth. The blocked stormwater culvert at the mouth of Puna Stream may have been blocked during earlier village road construction.

In the aftermath of Hurricane Val in 1991, the mouths of Tapua Stream and Puna Stream apparently became clogged with garbage, rocks and soil material. Standing salt water changed water quality just inland of the stream mouth and culverts. The change in water quality apparently caused a die-off of many mangrove trees along the northeast side of the Tapua Stream (Steele, 1999).

WETLAND VEGETATION

November 1999 Survey

Art Whistler of Isle Botanica conducted a botanical survey of the Aoa wetland on November 3 and 17, 1999. Mr. Whistler was part of a three-person field survey team organized by Pedersen Planning Consultants that observed wetland vegetation, habitat for aquatic fish and invertebrates, stream hydrology, as well as land uses within and adjacent to the wetland. His observations are summarized in the following paragraphs.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-5 Fresh-Water Swamp

The fresh-water swamp was strongly dominated by fau (beach hibiscus). The spreading branches of the beach hibiscus occasionally formed thickets that impeded access through them. Ifi (Tahitian chestnut) was also common.

Other trees such as leva (coconuts), aoa (Samoan banyans), falaga (Barringtonia samoensis), milo (Pacific rosewood), poumuli (Fluggea flexuosa), gatae (coral tree), laupata (Macaranga harveyanna), and laufala (screwpine) were observed in smaller numbers. With the exception of poumuli, all of these trees are native to American Samoa.

Smaller numbers of oriental togo (mangrove) were present near the mouth of Tapua Stream. As stated earlier, the health of some of these species has been affected by the loss of regular tidal exchange, higher concentrations of salt water, and related changes in the water quality of the swamp.

The understory of the fresh-water swamp was muddy and contained little groundcover. The species present have to contend with low light conditions and constant muddy soils.

The most common plant species were seedlings and saplings of ifi (Tahitian chestnut), as well as some other species such as nonu (Indian mulberry), auauli (Samoan ebony), filimoto mafatifati (Geniostoma rupestre), mosooi (Cananga odorata), oa (Bischofia javanica), as well as a few stunted banana trees. Saato (swamp fern) formed clumps in a few locations, particularly in more sunny areas. In standing water, the weed Struchium sparganophorum was common.

Various epiphytes were common on tree trunks and stumps. These plants included various species such as:

• the ferns Pyrrosia lanceolata, laugasese (Davallia epiphylla) and laugasese (Davallia solida); • laugapapa (bird’s nest fern)and lau magamaga (Phymatosorus grossus); • vines such as lau mafiafia (wax flower); and, • mati (the epiphytic tree or shrub dyer’s fig).

Fresh-Water Marshes

Two marsh areas are located in the Aoa wetland.

One marsh area is situated south and west of Olomoana School. Most of this marsh contained standing water. The downstream portion of this marsh was dominated by harveyana (salt grass) that formed dense patches. Further inland, away from the influence of seawater, the marsh is dominated by mauutoga (commelina). The commelina is mixed with smaller amounts of utuutu (water chestnut), selesele (Mariscus javanicus), another selesele (Rhynchospora corymbosa), willow primrose, sanasana (Job’s tears), and swamp fern. At its southwest end, the commelina is entirely replaced by a dense combination of willow primrose and fue saina (mile-a-minute weed). The southwest end contained a banana plantation.

A second marsh was located at the base of upland slopes along the southeast side of the wetland. Subsistence agricultural plantations were located on the east and west sides of the marsh. This area was formerly a taro plantation that was abandoned. This marsh was

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-6 dominated by willow primrose along with patches of beach hibiscus, mile-a-minute vine, and Job’s tears. Swamp Forest

A swamp forest was located along edges of the standing water and marshes, e.g., around the marsh south and west of Olomoana School. Swamp forest also extended inland to near the base of upland slopes on the south side of the Aoa wetland.

Most of the swamp forest was characterized by beach hibiscus without the presence of littoral species such as mangrove or Pacific rosewood. Smaller banana plantations and houses replaced the fresh-water swamp along its inland margins.

Vegetation Trends

Decline of Former Mangrove Forest

Significant changes have occurred in the vegetation of the Aoa wetland since 1976. Some four acres of mangrove were observed in 1976. In 1991, Biosystems Analysis, Inc. observed oriental mangrove, red mangrove, and beach hibiscus in the fresh-water swamp. During the November 1999 survey, the remnants of the former mangrove forest represented only scattered mangrove trees along the margins of the fresh-water swamp. Consequently, mangrove trees may be naturally dying and/or some residents may be harvesting mangrove trees for firewood or other purposes. In either case, domination of the fresh-water swamp by beach hibiscus and Tahitian chestnut can be expected to continue in areas that are not changed by landfills for residential development and agricultural plantations.

Changing Characteristics of the Fresh-Water Marsh

The fresh-water marsh south of Olomoana School exhibited all the appearances of having been a former taro patch since it was dominated by commelina in November 1999. Following the abandonment of a taro plantation, the domination by commelina usually follows. However, this area did not appear to be a habitat where taro is typically grown, e.g., close to the ocean. Former surveys by both Whistler in 1976 and Biosystems Analysis, Inc. in 1991 did not identify the presence of taro in this location.

It is anticipated that patches of water chestnut will eventually spread over the entire downstream area if it can out compete the typically weedy commelina. Such a trend will require the lack of disturbance, e.g., cultivation of taro, in the fresh-water marsh. It is unusual that California grass, which dominated this area in 1991, was not present in November 1999. If true, the California grass was replaced by commelina, due possibly to some change in habitat factors.

The disturbed marsh on the southeast side of the Aoa wetland was also quite different than that previously described by Biosystems Analysis, Inc. in 1992. Biosystems Analysis, Inc. noted “.....scattered patches of beach hibiscus with an herbaceous layer of grasses”. As stated earlier, PPC observed that the marsh was dominated by willow primrose along with patches of beach hibiscus, mile-a-minute vine, and Job’s tears in November 1999. One or more of these species may dominate for a long time. However, native plants such as water chestnut may invade and

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-7 become dominant if there is a nearby seed source since this plant is presently absent from the marsh.

AQUATIC FISH AND INVERTEBRATES

General

On November 3, 1999, Charles Chong of the PPC field survey team made observations of aquatic fish and invertebrates along portions of Tapua Stream and its upland tributary, Lepa Stream. His observations are summarized in the following paragraphs.

Aoa wetland contained a small estuary just upstream of the Tapua Stream mouth. The estuary was fed by Lepa Stream surface runoff from Tapua Stream and Lepa Stream. Puna Stream was completely dry during the November 3 survey; no flows were observed at its confluence with Tapua Stream.

Tapua Stream was also dry for a short distance between Aoa wetland the base of upland slopes on the south side of the wetland. The stream flow through one set of culverts just upstream of the Tapua Stream mouth was less than 0.5 cfs during the survey.

Fish Small estuary upstream of Tapua Stream mouth

The estuary inside Aoa wetland and inland portion of Tapua Stream contained nearly all of the fresh-water fishes known to American Samoa. Within the estuary, Mugil and Kuhlia spp. were abundant as were other euryhaline fishes such as Periopthalmus.

The amphidromous gobioids, Stenogobius genivittatus and Eleotris spp., as well as fresh-water species Poecilia reticulata and P. mexicana, were common in the estuary. Other gobies, however, were not seen anywhere in the wetland. Lower stream flow and intermittent stream flow conditions may have prevented the presence of other gobies.

A few residents informed Charles Chong of the PPC survey team that anguillids were present in the upper reaches of Tapua Stream. Captive specimens, obtained by local residents, evidenced their presence in the stream. However, Chong observed no anguillids during the field survey.

Invertebrates

The invertebrates observed in Tapua Stream and Lepa Stream included the complete compliment of fresh-water molluscs, but only a portion of the crustaceans known to American Samoa. Immediately inland of the estuary, for example, two unidentified species of neritid snails were abundant in Tapua Stream. Sisiwai and two other species were common. Along upland Lepa Stream, only the larger smooth species of neritid snails was found.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-8 The crustacean fauna was dominated by Macrobrachium lar in the estuary as well as upstream. Two species of cariddean shrimp were found in lower densities upstream.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-9 Relative Abundance and Diversity of Fish and Invertebrates

A site specific summary of macrofaunal organisms observed during the survey is summarized in Table 4-3. Genera are listed in order of descending abundance within their taxonomic group.

TABLE 4-3 SUMMARY OF MACROFAUNAL ORGANISMS OBSERVED WITHIN AOA WETLAND AND LEPA STREAM Stream Location Fishes Crustaceans Molluscs Tapua Stream lowland/estuary Kuhlia Macrobrachium Neritina (2 spp.) Poecilia Thiara Mugil Clithon Periopthalmus Stenogobius Eleotris Lepa Stream None Caradina Neritina Atya Thiara Source: Chong, 2000

The relative abundance and diversity of fish and invertebrates along the Tapua Stream lowland/estuary and upland Lepa Stream are summarized in Table 4-4. While the estuary contain many species, the upper reaches of Lepa Stream had fewer species of fish and mollusks than expected. The characterization of relative abundance and diversity reflects a general comparison of the abundance and diversity of fish and invertebrates observed along Tapua Stream and Lepa Stream with all 10 sites evaluated for the Wetland Restoration and Enhancement Plan.

TABLE 4-4 RELATIVE ABUNDANCE AND DIVERSITY OF FISH AND INVERTEBRATES TAPUA STREAM AND LEPA STREAM

Fishes Crustaceans Molluscs Abundance Low Medium High Diversity Medium Medium High Source: Pedersen Planning Consultants, 2000

LAND USES IN THE VICINITY OF AOA WETLAND

Olomoana Elementary School is situated along the north side of wetland. A shoreline trail provides vehicular pedestrian access between the primary Aoa village area and the neighboring Vaiaga area.

With the exception of one or two residences, the south side of the wetland generally remained undeveloped as the base of upland slopes begins on the south side of Aoa wetland. However, the southeast portion of the Aoa wetland continued to be used for considerably more house sites and some subsistence agriculture. The filling of lands in the southeast part of the wetland will likely generate adverse consequences to Aoa Village through increased flooding of the former marsh and related property damages.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-10 Two ASPA groundwater wells (wells 151 and 152) and several residences are situated between the east margin of the Aoa wetland and the primary roadway to Aoa Village. At least two vehicular trails along the east side of the wetland provide access from the primary roadway to local residences.

Residential and subsistence agricultural activities also are located on the west side of the wetland. One home near the mouth of Vaitolu Stream contains a small man-made pool that is fed via a fresh-water spring. The presence of Macro- brachium lar, poeciliads, and prawn traps in the pool indicate that, at least, one family is using aquatic organisms as a food resource.

WETLAND RESTORATION AND ENHANCEMENT STRATEGIES

General

There are four potential opportunities for the restoration and enhancement of Aoa wetland. Three of these opportunities were originally identified by Biosystems Analysis, Inc. in the Comprehensive Wetlands Management Plan. A fourth option identified by Biosystems Analysis was refined by PPC based upon discussions with representatives of the ASCC Land Grant Program. The scope of these restoration and enhancement opportunities and related implementation strategies are presented in the following paragraphs.

Alternate Opportunities and Strategies

Option 1: Expand the West Boundary of the Wetland

Option 1 would expand the west boundary of the Aoa wetland and establish a stream channel through the middle of a 100 to 200-foot wide strip of land. Through considerable excavation and grading along the middle reach of Vaitolu Stream, the new stream channel would be fed from surface flow via Vaitolu Stream.

Option 2: Widen the Mouth of Vaitolu Stream

Option 2 would widen the mouth of Vaitolu Stream and extend the restored area roughly 250 feet inland of the stream mouth. Excavation would be required to gain tidal flow from the stream mouth, as well as accommodate the construction of a new 36-inch diameter culvert and new bridge over the existing shoreline vehicular trail.

Option 3: Establish a Fresh-Water Wetland Along Vaitolu Stream Channel Option 3 would be similar to Option 2 with the widening of Vaitolu Stream. The primary exception would be that tidal exchange from the nearshore waters would intentionally be blocked to establish a fresh-water wetland along the stream channel.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-11 Option 4: Restore Mangrove Forest Upstream of the Puna Stream and Tapua Stream Mouths

Restoration of the mangrove forest immediately upstream of the Puna Stream and Tapua Stream mouths (Figure 4-3) would initially require the clearing of sand, vegetation and solid waste material that presently blocks tidal exchange via the Puna Stream mouth. This effort will require clearing within the existing 12-foot wide x 3.5-foot high culvert upstream of the Puna stream mouth, as well as on the upstream and downstream sides of the culvert. A backhoe will also be needed to facilitate the excavation of sand and heavier solid waste material.

Machetes and weed-eaters can be used to mow vegetation upstream and downstream of the Tapua Stream and Puna Stream culverts. Lighter, solid waste material should be burned. Excess material should be bagged in plastic garbage bags; arrangements should be made with ASPA for a special collection of this material.

In November 1999, the double culverts underneath the shoreline vehicular trail were clear of any obstructions that might impede tidal exchange via the adjoining Tapua Stream mouth. Consequently, no clearing is anticipated at the Tapua Stream mouth or the upstream culvert underneath the shoreline trail.

The second task of the restoration effort would involve the planting of red and oriental mangrove trees within and along the margins of the estuary in the fresh-water swamp, as well as the banks of Tapua Stream and Puna Stream between the culverts and the fresh-water swamp.

Roughly 50 red mangroves should be planted within the streambed because this plant readily colonizes in estuaries and can sustain itself in waters with somewhat higher salt water concentrations (Stemmermann, 1981). Propagules or seedlings should be planted approximately three feet apart. Within three years, the mangroves should be thinned to about a six-foot spacing between each plant (Steele, 1999).

In contrast, 25 oriental mangroves would more desirably be planted along the stream banks because it is less tolerant of salt water. Propagules or seedlings should again be spaced approximately three feet apart. Plants should be thinned to a spacing of six feet within about three years.

Other smaller trees, shrubs and grasses that can survive successfully in a brackish, estuarine environment would supplement mangrove plantings. In-stream plantings of red mangrove within the estuary, for example, would be supplemented with approximately 25 fao trees (beach hibiscus). Along stream banks, the planting of oriental mangrove trees would be interspersed with about 25 milo trees (Thesepesia populnea). Salt resistant grasses would be planted in the estuary to increase the amount of available habitat of fish upstream of the Tapua Stream and Puna Stream outlets.

Comparative Benefits and Impacts

PPC’s evaluation of the four alternate restoration and enhancement strategies is summarized in Table 4-5. Option 4 would achieve significant benefits to wetland vegetation, reduce flood potential in the vicinity of the Puna Stream mouth, expand a fish spawning area in the estuary upstream of the Puna Stream mouth, and create new habitat for invertebrates. These potential benefits can be derived for considerably lower project costs.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-12 FIGURE 4-3 OPTION 4: RESTORE MANGROVE FOREST UPSTREAM OF THE PUNA STREAM AND TAPUA STREAM MOUTHS

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-13 TABLE 4-5 COMPARATIVE EVALUATION WETLAND RESTORATION AND ENHANCEMENT OPPORTUNITIES AOA WETLAND

Option Project Residential Subsistence Fish & Wetland Stormwater Flood Cost Land Uses Agriculture Invertebrate Vegetation Detention Hazards & Habitat Habitat Property Damage 1 SC SC MC LB SB LB LC 2 SC MC LC SB SB NBC MC 3 MC MC LC SB SB LB SC 4 LC LC NBC SB SB NBC LB

Notes: Potential project benefits were rated by PPC as follows: SB Significant project benefits LC Limited undesirable consequences MB Moderate project benefits MC Moderate undesirable consequences LB Limited project benefits SC Significant undesirable project impacts NBC No anticipated project benefits or undesirable consequences

Source: Pedersen Planning Consultants, 2000

The biggest risk associated with Option 4 is that frequent storm waves entering Aoa Bay will occasionally transport sand that will partially or completely block future tidal exchange. In the absence of regular tidal exchange, a significant change in the water quality of the estuary can adversely impact the health of mangroves. However, the same risk is associated with Option 2.

While past encroachment has been made on the west side of the Aoa wetland, the potential development costs associated with the implementation of options 1 and 3 appear unattractive in light of limited to moderate benefits. Limited to moderate to significant disruptions in existing residential land uses and subsistence agriculture would be generated by the development of options 1,2 or 3. Such change would likely annoy most residents who would be directly impacted by the project. Further, there is a limited to moderate probability that options 1, 2 or 3 would occasionally generate some flooding problems in the adjoining residential area.

Significant benefits associated with the planting of red and oriental mangroves are anticipated from options 2 and 3. The establishment of mangroves would desirably establish a coastal swamp forest and, at the same time, create new habitat for fish and invertebrates.

Recommended Option and Estimated Project Cost

The restoration of the mangrove forest immediately upstream of the Puna Stream and Tapua Stream mouths (Option 4) is recommended for implementation. This wetland restoration project is recommended because the project can provide multiple benefits to the Aoa wetland and Aoa Village for considerably lower project costs.

The costs associated with the restoration of the mangrove forest would primary be associated with the initial clearing of the Puna Stream mouth, as well as the subsequent collection and planting of mangrove, fau, and milo tree cuttings by the ASCC Land Grant Program. These estimated cost associated with the initial clearing of the Puna Stream mouth would be approximately $3,056 (Table 4-6). The planting of mangrove and riparian trees would require an expenditure of approximately $2,721 (Table 4-7). Consequently, the total project would cost an estimated $5,777.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-14 TABLE 4-6 PRELIMINARY COST ESTIMATE INITIAL CLEARING OF PUNA STREAM CULVERT LABOR Personnel Number Hours Hourly Rate ($) Cost ($) Supervisor 1 40 15 600 Heavy Equip. Operator 1 40 13 520 Laborer 2 40 6 480 All Personnel 4 160 $1,600 MATERIALS Item Quantity Unit Cost ($) Cost ($) Picks 3 15 45 Sledge Hammers 3 25 75 Shovel 3 22 66 Weed-eaters 3 300 900 Machetes 3 20 60 Garbage Bags 32 boxes 5 160 Wheel Barrows 3 50 150 All Materials $1,456 TOTAL LABOR AND MATERIALS $3,056 Source: Pedersen Planning Consultants, 2000

TABLE 4-7 PRELIMINARY COST ESTIMATE PLANTING OF MANGROVE AND RIPARIAN TREES UPSTREAM OF TAPUA AND PUNA STREAM MOUTHS LABOR Personnel Number Hours Hourly Rate ($) Cost ($) ASCC Plant Nursery Technician 1 104 10 1,040 ASCC Field Crew Leader 1 8 8 64 ASCC Field Crew Members 2 8 6 96 All Personnel 4 128 1,200 MATERIALS Item Quantity Unit Cost ($) Cost ($) Mangrove Propagules 75 5 375 Riparian Trees 50 3 150 Garbage Bags 25 boxes 5 125 All Materials 650 EQUIPMENT Shovels 3 22 66 Machetes 3 20 60 Picks 3 15 45 Wheel Barrows 2 50 100 Weed-eaters 2 300 600 All Equipment $871 TOTAL LABOR AND MATERIALS $2,721 Source: Pedersen Planning Consultants, 2000

Long-Term Monitoring and Site Maintenance Requirements

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-15

Long-term resource management activities associated with the restoration of the Aoa wetland should include the seasonal monitoring of selected resource characteristics and periodic site maintenance.

Resource Monitoring

The process of resource monitoring will involve completion of the following steps by ASEPA, ASCMP, or other ASG agency staff:

Long term monitoring of the Aoa wetland restoration project will require periodic examinations of:

• General wetland/stream hydrology; • Stream channel modifications; • the survival of new mangrove propagules and riparian tree seedlings; • type and number of aquatic fish and invertebrates in the Tapua Stream estuary; and, • changes in adjoining land uses.

The types of information needed, monitoring frequency, monitoring locations, and evaluation parameters are summarized in Table 4-8. A field work sheet or checklist, which can be used in the field, is provided in Table 4-9.

Future resource monitoring can be effectively performed through bi-annual site visits to the Aoa wetland. This approach will enable comparisons during wet (December through March) and dry (April through November) seasons of the year. Additional visits should also take place during and/or following significant stormwater events that may be generated from periods of significant rainfall.

Vehicular and pedestrian access to selected monitoring stations is largely dependent upon the cooperation and authorization of local residents and the Aoa Village Council. Assuming that residents cooperatively permit periodic access for long-term resource monitoring, monitoring should take place along the following two stream segments (Figure 4-4):

TABLE 4-8

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-16 TABLE 4-8 LONG-TERM RESOURCE MONITORING REQUIREMENTS AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN AOA WETLAND

Resource Information Monitoring Monitoring Monitoring Evaluation Requirement Frequency Method Location(s) Parameters Wetland/Stream Stream Flow 1 x (Dec-March) Visual observation Tapua Stream mouth to 300 feet upstream Presence of stream flow or obstructions to stream flow Hydrology 1 x (April-Nov) Visual observation Puna Stream to 200 feet upstream Wetland Outlet 1 x (Dec-March) Visual observation Tapua Stream mouth Presence of stream flow or obstructions to stream flow 1 x (April-Nov) Visual observation Puna Stream mouth Water Quality Changes in land 1 x (Dec-March) Take digital photos, document type and Between Tapua and Puna Stream mouths and Do new land uses generate non-point surface or subsurface of Lower Alao Wetland uses 1 x (April-Nov) estimated size, locate changes on field Tapua Stream Estuary discharges into wetland or Mulivaitele Stream channels? map Vegetation Survival of new 1 x (Dec-March) Take visual count of new mangrove Between most downstream culverts of Tapua Number of trees that remain trees 1 x (April-Nov) propagules and riparian tree seedlings and Puna Streams, and Tapua Stream Estuary Aquatic Fish Type and number 2 x (Dec-March) Collect driftnet samples of outgoing 100 feet upstream of Tapua Stream mouth. Changes in diversity and abundance of fish and and of fish and 2 x (April-Nov) larvae for 3-4 hour evening periods crustaceans Invertebrates crustaceans (see report narrative). Molluscs Type and number 2 nights (Dec-Mar) Mark-recapture technology or quadrant 100 feet upstream of Tapua Stream mouth. Changes in diversity and abundance of molluscs of molluscs 2 nights (Apr-Nov) counts at night. TABLE 4-9 FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN AOA WETLAND

Date(s) of field monitoring:______Name(s) of observer(s): Agency/Company Represented:

Tapua Stream Puna Stream STREAM AND WETLAND HYDROLOGY (Circle "yes" or "no".) 1 Is water flowing in the stream? Yes No Yes No 2a Are stream flows entering the wetland? Yes No Yes No b If no, what appears to be impeding stream discharge? Describe. 3 a Is the wetland outlet, e.g., culvert or stream mouth, clear to permit stream discharge? Yes No Yes No b If not, what appears to be impeding flow to the wetland outlet? Describe.

STREAM CHANNEL MODIFICATIONS 4 a Has the stream bank been altered and with what material has the alteration been made? Yes No Yes No ___ Basaltic rock wall ___ Concrete wall ___ Rock-filled gabions ___ Other, please describe: b If alteration has occurred, locate on field map _____ Check, when field map is so marked. 5 a Do existing rock walls, concrete walls or gabions appear to have been damaged from past or recent stormwater events? Yes No Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 6 a Is there evidence of bank erosion? Yes No Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 7 a Do you see evidence of a change in the stream flow path? Yes No Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked

SURVIVAL OF NEW WETLAND AND RIPARIAN PLANTS 8 a Count number of surviving new mangrove propagules b Count number of surviving riparian tree seedlings.

CHANGES IN LAND USE 9 a Document type and number of new land uses within 100 feet of stream channel. Number of facilities: Briefly describe each new facility: Residential Commercial Industrial Public Facility Community Facility Agricultural b Map location of new land uses on field map. ___ Check, when field map is so marked 10 a Do any existing land uses, within 100 feet of the stream channel or wetland perimeter, appear to have sustained damage from past or recent stormwater events? Yes No Yes No b If so, where? (Locate on field map.) ___ Check, when field map is so marked

NON-POINT DISCHARGES INTO STREAM CHANNEL OR WETLAND 11 Type of discharges: Briefly describe type of discharge: Piggery Stormwater Cesspool Industrial Commercial 12 Locate discharge on field map ___ Check, when field map is so marked FIGURE 4-4 RESOURCE MONITORING AREAS ALAO WETLAND

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-19 • begin at the Tapua Stream mouth and continue 300 feet upstream of the stream mouth;

• begin on the south side of the Puna Stream culvert, which is located underneath the shoreline vehicular trail connecting the east and west sides of Aoa Village, and continue 200 feet upstream of the Puna Stream culvert.

These monitoring areas should be used consistently unless unanticipated events, new land uses, or access issues prevent continued use. When necessary, changes in the location of monitoring stations should be documented and spatially located within the American Samoa GIS. PPC has provided digital files for the Wetland and Stream Restoration and Enhancement Plan that provide a departure point for locating the stream segments recommended for future resource monitoring.

Digital photos should be dated and subsequently be incorporated into the digital photo album for the Aoa wetland. This will enable a long-term comparison of resource information by ASG staff and/or consultants that may be used to perform long-term resource monitoring.

More specific monitoring of stream fauna should be made at the lower end of the Tapua Stream estuary. The estuary generally extends between the Tapua Stream/Puna Stream confluence and roughly 250 upstream of this confluence. Such monitoring should include the collection of driftnet samples of outgoing larvae, at least two times per month, for 3-4 hour evening periods. The driftnets (150-200 ųm mesh) should be attached to rebar pounded into the stream substrata, or simply suspended from trees or bridges to that the net is at the surface of the water. The samples would subsequently be preserved in ethanol. The type and number of fish and crustaceans should be enumerated using a dissecting microscope. Use of the dissecting microscope will likely require a 2-3 day training class and the necessary equipment.

Molluscs should be monitored in the lower part of the estuary by mark-recapture methodology, or quadrant counts at night since most are primarily nocturnal. Some training in these techniques is recommended.

Site Maintenance

Periodic site maintenance should take place within the project area approximately four times per year. Human disposal of solid wastes within the estuary and lower reaches of Tapua Stream and Puna Stream is expected to represent the primary focus of long-term site maintenance. The periodic long-term maintenance of the Tapua Stream and Puna Stream culverts is necessary to ensure adequate tidal exchange and the maintenance of brackish water quality.

A crew of three to four persons will be necessary to periodically walk the length of the lower channels of Puna Stream and Tapua Stream, as well as related culverts immediately upstream of the stream mouths. Such inspections would occur shortly after significant rainfall and stormwater events. Machetes and weed-eaters will be required to periodically trim vegetation along selected portions of the stream channel. The manual collection of solid wastes will also be necessary to minimize obstructions to stream discharge and effective tidal exchange.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Aoa Wetland, Page 4-20 Chapter Five VATIA WETLAND

LOCATION

Vatia Village is located along the north coast of the Island of Tutuila. One of two wetlands in Vatia was examined for this investigation. This wetland is situated on the southeast side of Vatia Village (Figure 5-1).

WETLAND HYDROLOGY

Sources of Surface Runoff to the Southeast Wetland

The primary source of water in the wetland is surface runoff from Faatafe Stream, Tufu Stream, and Mulivai Stream (Figure 5-2). These streams drain a portion of the northern slopes of Maugaloa Ridge. This drainage area extends downslope between Tiatauala Ridge and Matavalu Ridge.

Faatafe Stream originates near the 1,000-foot contour where it receives surface runoff from the east side of Maugaloa Ridge. The stream course flows downslope through the west side of the wetland, meanders through a small residential area, and eventually discharges along the south side of Vatia Bay.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-1 Figure 5-1 Location Map Southeast Wetland in Vatia

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-2 Figure 5-2 Southeast Wetland in Vatia Existing Conditions

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-3 Tufu Stream and two stream branches begin near the 1,200-foot elevation. Stream flows flow through the central part of the wetland. At about the 10-foot contour, Tufu Stream empties into Mulivai Stream along the east side of the wetland.

Mulivai Stream originates approximately 1,200-feet above mean sea level. The main stem of the stream and a west branch merge near the 50-foot contour. These flows, as well as downstream flows from Tufu Stream, eventually discharge at the mouth of Mulivai Stream.

Stream Flows

Median Stream Flows

No historical stream flow records are available for Faatafe, Tufu, and Mulivai Stream.

Stormwater Discharges and Related Flood Potential

Pedersen Planning Consultants made a hydrologic analysis of potential stormwater discharges to the southeast wetland in Vatia during a range of storm events. The computer modeling of potential stormwater events for a 2, 10, 50 and 100-year storm event suggest the generation of stormwater flows that may range between 504 cubic feet per second (cfs) for a 2-year storm event and 1,559 cfs for a 100-year storm.

TABLE 5-1 POTENTIAL STORMWATER DISCHARGES ALONG SOUTHEAST SIDE OF VATIA BAY 2,10,50 AND 100-YEAR STORM EVENTS IN CUBIC FEET PER SECOND (CFS)

Stream 2-Year Storm 10-Year Storm 50-Year Storm 100-Year Storm

Faatafe Stream mouth 23 42 84 104

Tufu/Mulivai Stream mouth 481 731 1,133 1,455

All Streams 504 773 1,217 1,559

Source: Pedersen Planning Consultants, 2000.

The potential flood plain associated with a 100-year storm event was mapped by the Federal Emergency Management Agency (FEMA) in May 1991. Available flood insurance rate maps prepared by FEMA suggest potential flooding downstream of the wetland. Such flooding would likely occur:

• up to 100 feet west of Faatafe Stream; • within the residential area east of Faatafe Stream to roughly 100 feet east of Mulivai Stream.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-4 During a November 4, 1999 survey, the PPC survey team surveyed lower Faatafe Stream between the north end of the wetland to the mouth of Faatafe Stream. Observations made by PPC during the survey suggest that the lower drainage course has been modified to accommodate a recent expansion of the Mormon Church complex, as well as past residential development along Faatafe Stream.

The recent construction of a Methodist church east of the Mormon Church complex has altered the stream course of Mulivai Stream. It is uncertain whether or not this stream course modification and possible fill prevented a stream discharge at the mouth of Mulivai Stream. No flow was observed along the lower end of Mulivai Stream during the survey. PPC was advised later by American Samoa Coastal Management Program representatives that an illegal fill of the wetland was under review by the American Samoa Government Southern boundary of Mormon Church (Mitchell, 1999). complex, adjacent to Faatafe Stream

If the hydrologic connection between lower Mulivai Stream has been blocked by recent wetland or stream fill activities, an increased stream discharge can be expected along Faatafe Stream. In essence, an increased discharge along Faatafe Stream would only increase the flood potential to residential properties along the east and west sides of this drainage.

Hydrologic Outlet to Vatia Bay

As stated earlier, the mouths of Faatafe Stream and Mulivai Stream represent the hydrologic outlets from the southeast wetland of Vatia. Two sets of culverts are situated below a shoreline vehicular trail that is located along southeast side of Vatia Bay.

A 17.5-foot wide x 5-foot high concrete culvert is located at the mouth of Faatafe Stream. This culvert is in good physical condition and is capable of accommodating stormwater flows from a 50-year storm event.

At the mouth of Mulivai Stream, there are three, 3-foot diameter culverts. These concrete culverts are in fair condition; however, they are undersized to handle stream flows from a potential 50-year stormwater event.

WETLAND VEGETATION

November, 1999 Survey

On November 4 and 17, 1999, Art Whistler of Isle Botanica conducted a botanical survey of the Faatafe Stream channel between the north end of the wetland and the Faatafe Stream mouth. The lower stream segment extends approximately 850 feet southwest and southeast of the stream mouth.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-5 Mr. Whistler was part of a three-person field survey team organized by Pedersen Planning Consultants that observed wetland vegetation, habitat for aquatic fish and invertebrates, stream hydrology, as well as land uses within and adjacent to the wetland. His observations are summarized in the following paragraphs.

Stream Mouth to Approximately 500 feet Upstream

The lower portion of the Faatafe Stream channel was highly disturbed. A rock wall, grassy area, and disturbed forest were situated along the first 300 feet of the west stream bank. The forest along the east bank of the stream represented a mixture of scattered fresh-water swamp, mangrove swamp, and littoral forest trees such as coconut, togo (oriental mangrove), milo (Pacific rosewood), and fau (beach hibiscus).

Further upstream, the stream channel widened before turning westward. An attractive, fresh- water swamp dominated by ifi (Tahitian chestnut) was situated in this area. Other species in this location included one or a few individuals of oriental mangrove, coconut, laufala (screwpine), and a clump of ofe palagi (bamboo).

Soils in this area were saturated and quite open since few plants could survive in this wet, shady habitat. The forest floor contained only seedlings of Tahitian chestnut, clumps of saato (swamp fern), and some falaga (Barringtonia samoensis) trees. Epiphytes were common on the trees. More prominent epiphytes included the fern lau tasi (Pyrrosia lanceolata), laugasese (Davallia epiphylla), and laugapapa (bird’s nest fern).

350 Upstream to North Side of Wetland

As the stream turned to the southeast, the vegetation changed significantly and revealed two other types of wetlands.

Swamp forest was observed along areas of standing or flowing water. This wetland was dominated entirely by beach hibiscus. The dense tangle of branches and shaded canopy virtually eliminated all other plant species except for some fue saina (mile-a-minute weed).

Disturbed fresh-water marsh was found both downstream and upstream from the beach hibiscus forest. The marsh was dominated mostly by sanasana (Job’s tears). Lesser amounts of fue lautetele (Merremia peltata) are also evident in the marsh along with laau fai lafa (candelabra) plants.

Along portions of this stream segment, the swamp forest and disturbed fresh-water marsh appeared to merge. These locations were characterized by scattered individuals and clumps of beach hibiscus, coconut, and gatae palagi (dadap) trees.

Job’s tears dominated underneath these trees. Lesser amounts of vao lima (T-grass), mile-a- minute weed, and losa honolulu (Honolulu rose) were also documented.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-6 Vegetation Trends

In 1992, Biosystems Analysis, Inc. surveyed this wetland as part of its preparation of a Comprehensive Wetlands Management Plan. Biosystems Analysis, Inc. recorded mangroves at the mouth of Faatafe Stream and described the southeast wetland as a freshwater wetland with coconut trees.

The most significant change to the wetland has been a reduction in size. In 1992, Biosystems Analysis estimated that the southeast wetland comprised about 18.5 acres. Between 1992 and 1999, about 2 to 3 acres have been lost by land fill activities associated with the development of the Mormon and Methodist church complexes.

Taro cultivation was no longer present within the disturbed marsh in November 1999. Former taro cultivation may have stopped due to the taro blight that occurred in the early 1990’s.

A change in the mangrove forest, just upstream of the Faatafe Stream mouth, has occurred since 1992. Biosystems noted the presence of both red and oriental mangrove. In November 1999, only oriental mangrove was recorded. This lower stream area is now best classified as a freshwater swamp forest.

AQUATIC FISH AND INVERTEBRATES

General

On November 4, 1999, Charles Chong of the PPC field survey team made observations of aquatic fish and invertebrates along the lower 850 feet of Faatafe Stream. His observations are summarized in the following paragraphs.

Just upstream of the stream mouth and main shoreline roadway, there was a small estuary that was fed by surface runoff from Faatafe Stream, as well as a nearby spring. During the time of the survey, stream flow was estimated to be less than 1 cfs.

Fish

Fishes observed in the lower estuary possessed a high species diversity and abundance of macrofauna. Mugil, Chanos, Periopthalmus, Eleotris, Kuhlia and Stenogobius were documented within the estuary.

Exotic Poecilia were abundant in the estuary and along the stream. Stiphodon, Anguilla, and Kuhlia spp. were common at lower and higher stream elevation.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-7 Invertebrates

Crustacean densities were high for Macrobrachium lar and Paleomon at lower and higher stream elevations. Caridina was common at higher stream elevations.

Three neritids were present at lower elevations. However, the two largest species were recorded at a higher stream elevation.

Relative Abundance and Diversity of Fish and Invertebrates

A site specific summary of macrofaunal organisms observed during the survey is summarized in Table 5-2. Genera are listed in order of descending abundance within their taxonomic group.

TABLE 5-2 SUMMARY OF MACROFAUNAL ORGANISMS OBSERVED WITHIN VATIA WETLAND

Stream Location Fishes Crustaceans Molluscs Faatafe stream mouth to 330 Kuhlia Macrobrachium Neritina (3 spp.) feet upstream Poecilia (2 spp.) Paleomon Mugil Periopthalmus Eleotris Sicyopterus Anguilla Stenogobius Chanos Faatafe Stream (about Kuhlia Macrobrachium Neritina (2 spp.) 1,250-1,350 feet upstream Poecilia Paleomon of stream mouth Sicyopterus Caradina Anguilla

Source: Chong, 2000

The relative abundance and diversity of fish and invertebrates observed within the Vatia wetland are summarized in Table 5-3. The characterization of relative abundance and diversity reflects a general comparison of the abundance and diversity of fish and invertebrates observed along two segments of Faatafe Stream with all 10 sites evaluated for the Wetland Restoration and Enhancement Plan.

TABLE 5-3 RELATIVE ABUNDANCE AND DIVERSITY OF FISH AND INVERTEBRATES IN FAATAFE STREAM

Fishes Crustaceans Molluscs Abundance High High Medium Diversity High Medium High

Source: Pedersen Planning Consultants, 2000

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-8 The stream segment appeared to contain a healthy assemblage of stream macrofauna. A potential increase in stream flow, which may have been generated from the filling of Mulivai Stream, may actually enhance amphidromous specie populations by allowing perennial recruitment into the stream.

LAND USES WITHIN SOUTHEAST WETLAND AND FAATAFE STREAM

The north end of the wetland and lower Faatafe Stream segment is primarily interspersed with single family residential land uses. A comparison of 1990 aerial photography and onsite conditions in November 1999 also suggest that two or three residential buildings have probably been built on the east side of the mangrove forest during the past decade.

As stated earlier, Mormon and Methodist church complexes have been constructed within the wetland during the past 10 years. An expansion of the Mormon complex was nearing completion at the time of the November 1999 survey. The development of these facilities is significant because site development carried out for both facilities reduced the size of the wetland and modified stream hydrology. The implications of potential stream alterations may become evident as larger stormwater events occur in the future.

WETLAND RESTORATION AND ENHANCEMENT STRATEGIES

General

There are two practical opportunities for the restoration and enhancement of the Vatia wetland and the lower reach of Faaatafe Stream. The scope of these restoration and enhancement opportunities and related implementation strategies are presented in the following paragraphs.

Alternate Opportunities and Strategies

Option 1: Restore Riparian Vegetation 450 Feet Upstream of Faatafe Stream Mouth

The first phase of stream restoration would require the collection and disposal of a wide variety of solid waste materials. Solid waste materials and garbage were discovered in the vicinity of the Faatafe Stream mouth, the roadway culvert underneath the shoreline roadway, and some portions of the upstream area. Manual collection will be sufficient to collect of this material. However, a larger dump truck may be required to haul larger materials to the Futiga landfill. Such equipment is available from either the American Samoa Power Authority or the American Samoa Department of Public Works.

The American Samoa Community College, Land Grant Program would subsequently initiate the planting of more vegetation along the first 450 feet upstream of the Faatafe Stream mouth (Figure 5-3). Propagated seedlings of some native trees may already be available at the ASCC Land Grant Program nursery. Recommended plantings along this stream segment would desirably include, at least, the following:

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-9 FIGURE 5-3 OPTION 1: RESTORE RIPARIAN VEGETATION 450 FEET UPSTREAM OF FAATAFE STREAM MOUTH

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-10

• 10 ateate (Wollastonia biflora) on the seaward side of the shoreline road culvert; • 50 togofafine (red mangroves) within the stream bed; • 25 fau (beach hibiscus) upstream of culvert between togofafine (red mangroves); • 25 ifi (Tahitian chestnut) and togo tane (oriental mangrove) along the stream bank; and, • 25 poumuli (Flueggea flexuosa) and fruit trees, e.g., mango, above the stream bank.

The initial planting of mangroves should be approximately 3 feet apart. In-stream plantings of red mangrove should be performed by ASCC Land Grant Program personnel. Within three years, red and oriental mangroves should be thinned to about a six-foot spacing between each plant (Steele, 1999).

The ASCC Land Grant Program would also encourage residents to participate in the planting of these trees along the east and west banks of the stream. ASCC Land Grant has considerable experience with encouraging community participation through its Forestry Stewardship Program. The enhancement of riparian vegetation and related participation of residents can best be accomplished by providing, at no charge, a total of about 30 tree seedlings to each household along the stream. However, the “no charge” arrangement would be conditional to the resident’s agreement to plant the new trees within 30 feet of the stream bank (Steele, 1995).

Option 2: Establish Wetland Vegetation Along South Boundary of Mormon Church Complex

Option 2 would establish wetland vegetation along the south boundary of the Mormon Church complex. Stream plantings along this stream segment would promote long-term conservation of the wetland and Faatafe Stream. This project would also help increase the site’s bio-diversity, as well as provide a source of fruit for both humans and flying foxes.

Plantings of ifi (Tahitian chestnut) and fuafua (Kleinhovia hospita) would be made along the south side of the Faatafe Stream that is immediately south of the Mormon Church complex. The plantings should extend for, at least, 150 feet along this stream segment.

If desired by one or more households west of the Mormon Church complex, similar plantings wetland vegetation could continue for up to another 250 feet. The potential extension of this project, however, would clearly require the authorization of these residents.

Comparative Benefits and Impacts

PPC’s evaluation of the two alternate restoration and enhancement strategies is summarized in Table 5-4. Option 1 would restore mangrove vegetation and provide significant improvements to wetland vegetation for a reasonable cost. Restoration of the mangrove vegetation along the lower reach of Faatafe Stream would also enhance the attractiveness of adjoining residential area.

Option 2 could also be developed for a reasonable cost. This option would also provide significant improvements to wetland vegetation and help deter further encroachment into the wetland.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-11

TABLE 5-4 COMPARATIVE EVALUATION WETLAND RESTORATION AND ENHANCEMENT OPPORTUNITIES VATIA WETLAND Option Project Residential Subsistence Fish & Wetland/ Stream Flood Hazards Cost Land Uses Agriculture Invertebrate Riparian Bank & Property Habitat Vegetation Stability Damage 1 LC MB NBC LB SB MB NBC 2 LC NBC NBC LB SB MB NBC Notes: Potential project benefits were rated by PPC as follows: SB Significant project benefits LC Limited undesirable consequences MB Moderate project benefits MC Moderate undesirable consequences LB Limited project benefits SC Significant undesirable project impacts NBC No anticipated project benefits or undesirable consequences Source: Pedersen Planning Consultants, 2000

Recommended Option and Estimated Project Cost

The restoration of the mangrove forest immediately upstream of the Faatafe Stream mouth (Option 1) is recommended for implementation. This wetland restoration project is recommended because the project can provide significant improvements to wetland vegetation, enhance the adjoining residential area, and provide a source of food to humans and flying foxes.

The costs associated with the restoration of the mangrove forest would primary be associated with the initial clearing of the Faatafe Stream mouth, culvert underneath the shoreline roadway, as well as the collection of some trash and solid waste material 450 feet upstream. The subsequent collection and planting of mangrove, fau, and milo tree cuttings would be carried out by the ASCC Land Grant Program.

These estimated cost associated with the initial clearing of the Faatafe Stream mouth, roadway culvert and upstream area would be approximately $2,996 (Table 5-5). The propagation of tree seedlings, the collection of tree cuttings, as well as the planting of recommended vegetation would cost an estimated $2,811 (Table 5-6). Consequently, overall project expenditures would cost an estimated $5,807.

TABLE 5-5 PRELIMINARY COST ESTIMATE CLEARING OF FAATAFE STREAM MOUTH, CULVERT, AND UPSTREAM AREA LABOR Personnel Number Hours Hourly Rate ($) Cost ($) Supervisor 1 40 15 600 Heavy Equip. Operator 1 40 13 520 Laborer 2 40 6 480 All Personnel 4 160 $1,600 MATERIALS Item Quantity Unit Cost ($) Cost ($) Picks 3 15 45 Sledge Hammers 1 25 25 Shovel 3 22 66 Weed-eaters 3 300 900 Machetes 3 20 60 Garbage Bags 20 boxes 5 100 Wheel Barrows 3 50 150 All Materials $1,346 TOTAL LABOR AND MATERIALS $2,946

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-12 Notes: Preliminary estimate assumes use of existing equipment owned by ASG Department of Public Works Source: Pedersen Planning Consultants, 2000

TABLE 5-6 PRELIMINARY COST ESTIMATE PLANTING OF MANGROVE AND RIPARIAN TREES UPSTREAM OF FAATAFE STREAM MOUTH

LABOR Personnel Number Hours Hourly Rate ($) Cost ($) ASCC Plant Nursery Technician 1 104 10 1,040 ASCC Field Crew Leader 1 10 8 80 ASCC Field Crew Members 2 10 6 120 All Personnel 4 134 $1,240 MATERIALS Item Quantity Unit Cost ($) Cost ($) Mangrove Propagules/Seedlings 50 5 250 Riparian Trees 50 3 150 Fruit Trees 25 5 125 Coastal Plants 10 5 50 Garbage Bags 25 boxes 5 125 All Materials $700 EQUIPMENT Shovels 3 22 66 Machetes 3 20 60 Picks 3 15 45 Wheel Barrows 2 50 100 Weed-eaters 2 300 600 All Equipment $871 TOTAL LABOR AND MATERIALS $2,811

Source: Pedersen Planning Consultants, 2000

Long-Term Monitoring and Site Maintenance Requirements

Long-term resource management activities associated with the Vatia wetland restoration, along the lower reach of Faatafe Stream, should include the seasonal monitoring of selected resource characteristics and periodic site maintenance.

Resource Monitoring

The process of resource monitoring will involve completion of the following steps by ASEPA, ASCMP, or other ASG agency staff:

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-13 Long term monitoring of the Vatia wetland restoration and enhancement project will require periodic examinations of, at least, the following:

• the presence of stream flow; • potential impedances to stream discharge; • potential changes in the flow path of Faatafe Stream; • evidence of eroding stream bank areas; • potential failures or damages to gabion baskets or rock walls along the stream bank; • survival of planted, riparian and wetland vegetation; • potential flood damages to residential properties; • changes in land uses immediately adjacent to the stream banks; • point-source discharges, e.g., wastewater from piggeries; and, • changes in the type and number of fish and invertebrates near the stream mouth.

The types of information needed, monitoring frequency, monitoring locations, and evaluation parameters are summarized in Table 5-7. A field work sheet or checklist, which can be used in the field, is provided in Table 5-8.

Future resource monitoring can be effectively performed through bi-annual site visits to the Vatia wetland. This approach will enable comparisons during wet (December through March) and dry (April through November) seasons of the year. Additional visits should also take place during and/or following significant stormwater events that may be generated from periods of significant rainfall.

Vehicular and pedestrian access to selected monitoring stations is largely dependent upon the cooperation and authorization of local residents and the Vatia Village Council. Assuming that residents cooperatively permit periodic access for long-term resource monitoring, field monitoring should begin at the stream mouth and extend 500 upstream. The only specific monitoring station within this area would be established approximately 10 feet upstream of the stream mouth where fish and invertebrate collections will take place.

Recommended monitoring stations or sites should be used consistently unless unanticipated events, new land uses, or access issues prevent continued use. When necessary, changes in the location of monitoring stations should be documented and spatially located within the American Samoa GIS. PPC has provided digital files for the Wetland and Stream Restoration and Enhancement Plan that provide a departure point for locating future resource monitoring stations along Faatafe Stream.

All photographs should be incorporated into the digital photo album developed by PPC in conjunction with the Wetland/Stream Restoration and Enhancement Plan. This will enable a long-term comparison of resource information.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-14 TABLE 5-7 LONG-TERM RESOURCE MONITORING REQUIREMENTS AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN VATIA WETLAND

Resource Information Monitoring Monitoring Monitoring Evaluation Requirement Frequency Method Location(s) Parameters Wetland/Stream Stream flow 1 x (Dec-March) Visual observation Faatafe Stream mouth to 500 feet upstream Presence of stream flow or obstructions to stream flow Hydrology 1 x (April-Nov) Visual observation Wetland outlet 1 x (Dec-March) Visual observation Faatafe Stream mouth Presence of stream flow or obstructions to stream flow 1 x (April-Nov) Visual observation Stream Modifications Changes to 1 x (Dec-March) Take digital photos, measure manually 500 feet upstream of Faatafe Stream mouth Evidence of bank erosion, changes in flow path, or new stream banks 1 x (April-Nov) using tape measure, record type & size, manmade structures along stream bank (e.g., rock walls) locate changes on map, incorporate data into GIS Vegetation Survival of new 1 x (Dec-March) Take visual count of new mangrove Betweem stream mouth and 500 feet upstream Number of plants that remain vegetation 1 x (April-Nov) propagules, riparian and fruit trees, and coastal plants Water Quality Changes in land 1 x (Dec-March) Take digital photos, document type and Within 100 feet of Faatafe Stream channel Do new land uses generate non-point surface or subsurface uses 1 x (April-Nov) estimated size, locate changes on map, discharges into wetland or stream channel? incorporate data into GIS Aquatic Fish Type and number 2 x (Dec-March) Collection of driftnet samples of outgoing10 feet upstream of Faatafe Sream mouth Changes in diversity and abundance of fish & crustaceans. and Invertebrates of fish and 2 x (April-Nov) larvae for 3-4 hour evening periods crustaceans (See report narrative.) Molluscs Type and number 2 x (Dec-March) Mark - recapture technology or 10 feet upstream of Faatafe Stream mouth Changes in diversity and abundance of molluscs. of molluscs 2 x (April-Nov) quadrant counts at night TABLE 5-8 FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN VATIA WETLAND

PAGE 1 OF 2 PAGES Date(s) of field monitoring:______Name(s) of observer(s): Agency/Company Represented:

Faatafe Stream STREAM AND WETLAND HYDROLOGY (Circle "yes" or "no".) 1 Is water flowing in the stream? Yes No 2a Are stream flows entering Leone Pala? Yes No b If no, what appears to be impeding stream discharge? Describe.

STREAM CHANNEL MODIFICATIONS 3 a Has the stream bank been altered and with what material has the alteration been made? Yes No ___ Basaltic rock wall ___ Concrete wall ___ Rock-filled gabions ___ Other, please describe: b If alteration has occurred, locate on field map _____ Check, when field map is so marked. 4 a Do existing rock walls, concrete walls or gabions appear to have been damaged from past or recent stormwater events? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 5 a Is there evidence of bank erosion? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 6 a Do you see evidence of a change in the stream flow path? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked

SURVIVAL OF NEW RIPARIAN PLANTS 7 Count number of surviving new riparian trees

CHANGES IN LAND USE 8 a Document type and number of new land uses within 100 feet of stream channel. Number of facilities: Briefly describe each new facility: Residential Commercial Industrial Public Facility Community Facility Agricultural b Map location of new land uses on field map. ___ Check, when field map is so marked 9 a Do any existing land uses, within 100 feet of the stream channel, appear to have sustained damage from past or recent stormwater events? Yes No b If so, where? (Locate on field map.) ___ Check, when field map is so marked

NON-POINT DISCHARGES INTO STREAM CHANNEL OR WETLAND 10 Type of discharges: Briefly describe type of discharge: Piggery Stormwater Cesspool Industrial Commercial 11 Locate discharge on field map. ___ Check, when field map is so marked TABLE 5-8 (CONTINUED) FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN VATIA WETLAND

PAGE 2 OF 2 PAGES

FISH AND INVERTEBRATES 12 Identify the type and number of fish observed via the collection of driftnet samples of outgoing larvae. Family Genus/Specie Number Observed a Fish

b Crustaceans

MOLLUSCS 13 Identify the type and number of molluscs that were observed by mark-recapture technology or quadrant counts. Family Genus/Specie Number Observed More specific monitoring of stream fauna should be made immediately upstream of the Faatafe Stream crossing of the shoreline vehicular trail to Vatia Village. Such monitoring should include the collection of driftnet samples of outgoing larvae, at least two times per month, for 3-4 hour periods in the evening. The driftnets (150-200 ųm mesh) should be attached to rebar pounded into the stream substrata, or simply suspended from trees or bridges to that the net is at the surface of the water. The samples would subsequently be preserved in ethanol. The type and number of fish and crustaceans should be enumerated using a dissecting microscope. Use of a dissecting microscope will likely require a 2-3 day training class and the necessary equipment.

Molluscs should be monitored by mark-recapture methodology, or quadrant counts at night since most are primarily nocturnal. Some training in these techniques is recommended for selected field monitoring personnel.

Site Maintenance

A one-time cleanup effort will represent an important first step toward long-term stream enhancement. However, the initial cleanup is of limited benefit if it is not associated with the implementation of a long-term maintenance strategy.

Periodic site maintenance should take place within the project area approximately four times per year. Household wastes along the lower reaches of Faatafe Stream are expected to represent the primary focus of long-term site maintenance. The periodic long-term maintenance of the Faatafe Stream culvert underneath the primary shoreline trail will be necessary to ensure adequate tidal exchange and the maintenance of brackish water quality.

A crew of three to four persons will be necessary to periodically walk the 450-foot length of lower Faatafe Stream, as well as related road culvert immediately upstream of the stream mouths. Such inspections would occur shortly after significant rainfall and stormwater events. Machetes and weed-eaters will be required to periodically trim vegetation along selected portions of the stream channel. The manual collection of solid wastes will also be necessary to minimize obstructions to stream discharge and effective tidal exchange.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vatia Wetland, Page 5-18 Chapter Six VAIPITO STREAM

LOCATION

The Vaipito Stream drainage is situated upland of the inner Pago Pago Harbor and Pago Pago Village (Figure 6-1). The stream segment investigated included the lower end of Vaipito Stream that extends from the Vaipito Stream mouth to about 2,725 feet upstream of the shoreline (Figure 6-2).

STREAM HYDROLOGY

Sources of Surface Runoff

The Vaipito Stream drainage encompasses approximately 1.36 square miles of land area (U.S. Army Corps of Engineers, Honolulu District, 1990). This drainage receives surface runoff from Gagamoe Stream, Laolao Stream, Pago Stream, Leau Stream, Vaima Stream, Utumoa Stream, and Aga Stream (Figure 6-2).

The Vaipito Stream drainage originates near the 1,200-foot elevation on the northwest slopes of Mt. Matafao. The main stem of Vaipito Stream flows through Pago Pago Village just east of Route 5. The stream channel passes along the northwest side of Pago Plaza and bisects Pago Park before discharging into the nearshore waters of inner Pago Pago Harbor.

The lower stream channel that bisects Pago Park also receives surface runoff from a second unnamed ditch and channel that is located on the south and east sides of Pago Pago Elementary School. This channel passes along the north side of a Mormon Church complex (on the southwest side of Route 1) and continues for about 800 feet before its confluence with the main stem of Vaipito Stream.

General Stream Characteristics

The lower Vaipito Stream channel segment represents a relatively narrow and deep channel. Exposed basalt boulders and man-made walls form the margin of the stream channel. The streambed typically contains a combination of medium to large basalt boulders, smaller rock cobble, sand, and decomposed organic material. Limited areas of the channel bottom are lined with concrete.

A considerable amount of household garbage and discarded organic material was found at various points within the streambed. With increased building densities in Pago Pago, a number of landowners have also encroached their site development upon stream banks to help increase the size of concrete driveways and vehicular parking areas.

Rock walls and rock-filled gabions are located along various points of the lower stream channel. They have apparently been installed to help prevent flood damages associated with higher stormwater events, as well as protect properties from erosion along the stream bank. However, stream bank hardening and alterations of stream flow path have significantly impacted stream hydrology. Increased stream velocities, combined with alterations in stream flow path, have contributed to the failing of some gabions along Vaipito Stream.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-1 Figure 6-1 Location Map Vaipito Stream Drainage

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-2 Figure 6-2 Vaipito Stream Segment Existing Conditions

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-3 Stream Flows

Historical Stream Flows

Intermittent stream flow records have historically been collected by the U.S. Geological Survey along two tributaries of Vaipito Stream (Table 6-1). The data gained from these stream gages provide an insight of runoff volumes that historically have emptied into lower Vaipito Stream.

TABLE 6-1 MEDIAN STREAM FLOW ESTIMATES TRIBUTARIES OF VAIPITO STREAM

Stream USGS Gage Location Stream Flow Estimated Gage Measurements Median Flow (cfs) Station (number) Vaima Stream 16949700 0.4 mile upstream from 20 0.16 Vaipito Stream. Utumoa Stream 16949800 0.6 mile upstream of 29 0.42 Vaipito Stream and immediately upstream of Vaipito intake. Utumoa Stream 16950500 0.2 mile downstream of 17 0.25 Utumoa Stream pipeline.

Source: Wong, 1996

Stormwater Discharges, Flood Potential, and Erosion

Pedersen Planning Consultants made a hydrologic analysis of potential stormwater discharges into inner Pago Pago Harbor via a range of potential storm events. Through hydrologic modeling, PPC determined that potential stormwater discharges into inner Pago Pago Harbor could range from 862 cubic feet per second (cfs) for a 2-year storm and about 3,683 cfs for a 100-year storm (Table 6-2). Consequently, significant stream flows can be carried by Vaipito Stream for more common 2-year events, as well as less frequent 100-year storms.

TABLE 6-2 STORMWATER RUNOFF DISCHARGES INTO INNER PAGO PAGO HARBOR FROM VAIPITO STREAM DRAINAGE 2,10,50, AND 100-YEAR STORM EVENTS IN CUBIC FEET PER SECOND (CFS)

Location 2-Year Storm 10-Year Storm 50-Year Storm 100-Year Storm Vaipito Stream 612 1,084 2,137 2,608 Unnamed Stream 220 391 775 947 Gagamoe Stream 30 53 104 128 TOTAL 862 1,528 3,016 3,683

Source: Pedersen Planning Consultants, 2000

Ten, 50, and 100-year flood plains determined by the U.S. Army Corps of Engineers, Honolulu District, in 1988 suggest that greater flood potential is generally downstream of the Vaipito

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-4 Stream/Pago Stream confluence. In a related reconnaissance report, the U.S. Army Corps of Engineers concluded:

“The greatest flood problem occurs in the downstream area, approximately 600 feet above the main highway (Route 1) down to the mouth. While the outlet has ample flood carrying capacity, the existing bankfull capacity of Vaipito Stream in the land-filled area (Pago Park) is 1,100 cfs, a discharge slightly greater than a 2-year flood” (U.S. Army Corps of Engineers, 1988).

While flooding typically occurs on the lands within Pago Park, flooding in this area typically generates limited to no property damage since few structures are located within the Park. In recent years, however, more governmental buildings have been constructed along Route 1 and the west margin of the Park. The blockage of culverts along Route 1 frequently generates flooding within and around these buildings following more frequent storm events.

Erosion poses a problem upstream of Route 1, particularly along bends of the stream. “Stream banks exposed to the erosive forces of the stream are provided minimal protection with a thin concrete blanket” (U.S. Army Corps of Engineers, 1988).

Stream Capacities TABLE 6-3 ESTIMATED VAIPITO STREAM CAPACITIES

The U.S. Army Corps of Engineers Station Location Capacity (cfs) also modeled stream capacities as 0+00 to 7+00 1,600 part of its 1988 reconnaissance 7+00 to 18+00 1,100 report for Vaipito Stream (Table 6- 3). 18+00 to 28+00 1,200 28+00 to 38+00 700 38+00 to 54+00 870 VEGETATION Source: U.S. Army Corps of Engineers, 1988 November 1999 Survey

Art Whistler of Isle Botanica conducted a botanical survey of the Vaipito Stream segment on November 4, 1999. Mr. Whistler was part of a three-person field survey team organized by Pedersen Planning Consultants that observed wetland vegetation, habitat for aquatic fish and invertebrates, stream hydrology, as well as land uses within and adjacent to the wetland. His observations are summarized in the following paragraphs.

Vaipito Stream Mouth and Confluence with Unnamed Stream

The stream banks, between the Vaipito Stream mouth and its confluence with the unnamed drainage from Pago Pago Elementary School, were dominated by a mixture of alien plant species. Some of these species were typical of a wetland; others were indicative of an upland environment. Most of the relatively flat stream bank areas were characterized by salt grass (Paspalum vaginatum), Fimbristylis cymosa, and carpet grass (Axonopus compressus), as well as scattered concentrations of fue moa (beach morning-glory). Roughly 30 other alien herbaceous plants were noted along the stream banks just upstream of the Vaipito Stream mouth. Along the south bank of the stream, there were thickets of wild tamarind (Leucaena leucocephala), scattered fau (beach hibiscus) trees, patches of elephant grass (Pennisetum purpureum), beggar’s tick (Bidens alba), beach morning-glory, and

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-5 California grass (Brachiaria mutica). Only fau (beach hibiscus) and Fimbristylis cymosa are native plants.

Between Unnamed Stream/Vaipito Stream Confluence and Route 1

Between the unnamed stream/Vaipito Stream confluence and Route 1, the Vaipito Stream channel became narrower. The stream bank typically was lined with a basaltic rock or concrete wall. California grass was dominant immediately upland of the stream channel margin. Lesser amounts of Sorghum sudanense, fue saina (mile-a-minute vine), beggar’s tick, taamu (giant taro), sanasana (Job’s tears), and bananas were also evident along this stream segment.

Upstream of Route 1

Upstream of Route 1, the Vaipito Stream became increasingly channelized. Stream banks represented a combination of basaltic rock walls, concrete walls, rock-filled gabion baskets, and exposed dirt embankments. These characteristics left a narrow zone for the growth of vegetation.

Job’s tears, California grass, taamu (giant taro) and mile-a-minute vine were prevalent along stream segments that were characterized by dirt embankments. Various trees were also scattered along the stream banks. These trees primarily included ulu (breadfruit), vavae (kapok), beach hibiscus, falaga (Barringtonia samoensis), pulu (banyan), lau pata (Macaranga harveyana), mango, coconut, and banana.

Vegetation Trends

Lower Vaipito Stream was once characterized by a healthy mangrove swamp. However, the swamp was filled by the U.S Navy in the early 1960’s to support past naval activities. Subsequently, the use of the landfill area was converted to its present day recreational use with the establishment of Pago Park.

In 1996, significant restoration efforts were made by the American Samoa Environmental Protection Agency and the American Samoa Community College, Land Grant Program along selected portions of lower Vaipito Stream.

Following initial coordination with the pulenuu and village council of Pago Pago Village, ASEPA and ASCC Land Grant program personnel planted 127 trees just upstream of the Vaipito Stream mouth on September 28, 1996. These trees were planted along the east side of the stream. In mid-October and early November of 1996, an additional 1,000 feet of stream bank was planted upstream of Vaipito Stream’s unnamed lower confluence. Most of 238 trees planted were seedlings that were propagated at ASCC Land Grant facilities during the summer of 1995. One exception was fau trees that represented 2.5-foot long cuttings. All of the trees were planted and spaced at six-foot intervals. Falaga (Barringtonia samoensis) was planted along

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-6 the lower bank above mean sea level. Mangroves were planted downstream of the foot bridge that connects Pago Park and the vehicular parking area at Pago Plaza (Steele, 1996).

Between Route 1 and the Vaipito Stream/Pago Stream confluence, an additional 205 trees were planted in late December, 1996. This restoration effort primarily included the planting of ifi and falaga. With the presence of more riparian vegetation along this stream segment, fewer trees were required for stream bank restoration (Steele, 1996).

Despite these aggressive efforts, lower Vaipito Stream remains a highly degraded plant habitat. There is no utuutu or vao tuaniu, or native marsh vegetation along the stream banks. There also is very little falaga or ifi along the stream banks. Their absence, combined with the presence of banana, mango, and kapok are indicative of disturbance.

AQUATIC FISH AND INVERTEBRATES

General

On November 4, 1999, Charles Chong of the PPC field survey team made observations of aquatic fish and invertebrates along selected portion of lower Vaipito Stream. An upland site location was also investigated along Utumoa Stream, a significant upland tributary of Vaipito Stream (Figure 6-3). His observations are summarized in the following paragraphs.

Stream flows observed during the survey were generally fast-moving along the length of lower Vaipito Stream. A flow of about 2 to 3 cfs was observed at the Vaipito Stream mouth. The stream mouth terminated with a fast riffle entering inner Pago Pago Harbor.

A considerable amount of household garbage and other solid waste material was observed through much of the stream course.

Fish

An individual unidentified goby was observed along Utumoa Stream. Three unidentified individual gobies were documented in a pool below a small gage dam. With the exception of these fish, the only other fish observed along the stream were Poecilia.

Kuhlia and Mugil spp. were abundant near the Vaipito Stream mouth. However, Kuhlia spp. was absent upstream of the stream mouth.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-7 FIGURE 6-3 FISH AND INVERTEBRATE SURVEY LOCATIONS

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-8 Invertebrates

The lower Vaipito Stream segment possessed higher densities of crustaceans at lower elevations, as well as upstream along Utumoa Stream, a major upland tributary. Healthy crustacean fauna appeared to be pristine upstream of the residential area along Vaipito Stream. In contrast, lower specie diversity was evident adjacent to residential areas.

Marcrobrachium lar, as well as Caridina and Macrobrachium lutimanus, was abundant upstream along Utumoa Stream. Two species of neritid molluscs were present along Utumoa Stream, but were not abundant.

Along lower Vaipito Stream, Macrobrachium lar remained abundant downstream. Macrobrachium australe was common. One specie of molluscs was also observed along the lower elevations of the stream.

Relative Abundance and Diversity of Fish and Invertebrates

A site specific summary of macrofaunal organisms observed during the survey is summarized in Table 6-4. Genera are listed in order of descending abundance within their taxonomic group.

TABLE 6-4 SUMMARY OF MACROFAUNAL ORGANISMS OBSERVED ALONG VAIPITO STREAM DRAINAGE

Stream Location Fishes Crustaceans Molluscs Vaipito Stream mouth to Kuhlia Macrobrachium Neritina Route 1 crossing Mugil (2 spp.) Poecilia Unidentified Graspid crab Utumoa Stream Unidentified goby Caradina Neritina (2 spp.) Macrobrachium (2 spp) Source: Chong, 2000

The relative abundance and diversity of fish and invertebrates along the Vaipito Stream drainage is summarized in Table 6-5. The characterization of relative abundance and diversity reflects a general comparison of the abundance and diversity of fish and invertebrates observed along portions of the Vaipito Stream drainage with all 10 sites evaluated for the Wetland/Stream Restoration and Enhancement Plan.

Vaipito Stream contained a high diversity and abundance of invertebrates. However, fish diversity and abundance were low.

TABLE 6-5 RELATIVE ABUNDANCE AND DIVERSITY OF FISH AND INVERTEBRATES VAIPITO STREAM

Fishes Crustaceans Molluscs Abundance Low High Low Diversity Low High Medium

Source: Pedersen Planning Consultants, 2000 LAND USES ADJACENT TO VAIPITO STREAM

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-9 Most of lower Vaipito Stream segment is situated immediately adjacent to residential uses. Seaward of the Route 1 bridge, Pago Plaza and some public facilities area are located immediately adjacent to the stream channel.

Immediately upstream of the stream mouth, Pago Park is situated along the north and south sides of Vaipito Stream.

Solid waste discarded from the residents along Vaipito Stream poses the greatest impact upon stream hydrology and aquatic habitat. However, discarded solid waste material did not appear to significantly constrain the flow of surface runoff along the main stem of the stream.

RIPARIAN RESTORATION AND ENHANCEMENT STRATEGIES

General

Only one practical opportunity was identified for the restoration of lower Vaipito Stream. The scope of this restoration opportunity and related implementation strategies are presented in the following paragraphs. The potential benefits and impacts derived from the implementation of the recommended strategies are subsequently evaluated and compared with a “no action” option.

Opportunities and Strategies

Option 1: Restore Mangrove Forest along Lower Vaipito Stream

The initial phase of this restoration effort will involve a general cleanup of lower Vaipito Stream (Figure 6-4). The cleanup should be made between the Vaipito Stream mouth and the Route 1 crossing over Vaipito Stream. This effort will require the collection and disposal of a wide variety of solid waste materials for approximately 1,360 feet upstream of the stream mouth. Manual collection will be sufficient to collect most of this material. However, a larger dump truck may be required to haul larger materials to the Futiga landfill. Available equipment from either the American Samoa Power Authority or the American Samoa Department of Public Works should be requested and used to support the cleanup effort.

Following the initial stream cleanup, roughly 220 plantings of red mangrove (Rhizophora mangle) and 220 oriental mangrove (Bruguiera gymnorrhiza) should be made between the stream mouth and the foot bridge that connects the north and south sides of Pago Park. This segment of the stream extends roughly 650 feet upstream of the stream mouth.

FIGURE 6-4

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-10 OPTION 1: RESTORE MANGROVE FOREST ALONG LOWER VAIPITO STREAM

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-11 Red mangrove should be planted within the stream bed since red mangrove can sustain itself in waters with somewhat higher salt water concentrations (Stemmermann, 1981). In contrast, oriental mangroves should be planted higher along stream banks (Steele, 1999).

The initial planting of mangroves propagules or seedlings should be approximately 3 feet apart. Within three years, mangroves should be thinned to about a six-foot spacing between each plant (Steele, 1999).

The diversity of riparian vegetation could also be enhanced with the addition of 100 ifi (Tahitian chestnut) and falaga along the stream banks. However, these trees should be planted at least 200 feet upstream of the Vaipito Stream mouth to keep the trees away from stream areas subjected to tidal influence.

Trees along the stream banks would also be interspersed with the planting of approximately 100 littoral/coastal plants. Such plantings would include a combination of fetau, pu’a, gatae and talie.

In-stream plantings of red mangrove should be carried out by experienced technicians of the ASCC Land Grant Program. However, Land Grant representatives should attempt to involve local residents in the replanting of oriental mangrove, as well as ifi and falaga trees along the stream banks.

Option 2: No Action

ASEPA and the American Samoa Community College, Land Grant Program completed a significant stream restoration project in 1996 that resulted in the planting of some 569 trees along lower Vaipito Stream. In view of these improvements, Option 2 would make no further stream restoration and enhancement improvements along Vaipito Stream.

Comparative Benefits and Impacts

PPC’s evaluation of the two alternate restoration and enhancement strategies is summarized in Table 6-6. Option 1 would restore mangrove vegetation just upstream of the Vaipito Stream mouth and provide significant improvements to wetland and riparian vegetation, as well as stream bank stability, for a reasonable cost. These improvements would also enhance the attractiveness of adjoining Pago Park and not constrain recreational uses in this area. The presence of government lands in the restoration area will also facilitate access to future plantings and thinning activities, as well as long-term monitoring. In addition, some nominal improvements in fish and invertebrate habitat may be generated from in-stream plantings of the red mangrove.

The viability of mangrove restoration upstream of the Vaipito Stream mouth has some risks. Larger stormwater events may remove all plantings until the mangrove trees become well established. In addition, mangrove plantings will also somewhat diminish the capacity of the stream to discharge higher stream flows following stormwater events.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-12 TABLE 6-6 COMPARATIVE EVALUATION RIPARIAN RESTORATION AND ENHANCEMENT OPPORTUNITIES LOWER VAIPITO STREAM

Option Project Residential Subsistence Fish & Wetland/ Stream Flood Hazards Cost Land Uses Agriculture Invertebrate Riparian Bank & Property Habitat Vegetation Stability Damage 1 LC NBC NBC LB SB SB NBC

2 NBC NBC NBC NBC LC NBC NBC

Source: Pedersen Planning Consultants, 2000

Recommended Option and Estimated Project Cost

The restoration of the mangrove forest immediately upstream of the Vaipito Stream mouth (Option 1) is recommended for implementation. This wetland restoration project is recommended because the project can provide significant improvements to wetland vegetation, enhance the adjoining recreational area, and possibly provide increased habitat for fish and invertebrates.

The costs associated with the restoration of the mangrove forest would primary be associated with the initial clearing of solid waste material from the lower reach of Vaipito Stream. More specifically, the cleanup would be made between the stream mouth and the Route 1 crossing of Vaipito Stream. The subsequent collection and planting of mangrove, ifi, and falaga tree cuttings would be carried out by the ASCC Land Grant Program.

These estimated cost associated with the initial clearing of the Vaipito Stream mouth and the upstream area would be $2,036 (Table 6-7). The planting of mangrove and native riparian trees would cost an estimated $5,251 (Table 6-8). Consequently, the total project cost anticipated for the overall project is roughly $7,287.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-13 TABLE 6-7 PRELIMINARY COST ESTIMATE CLEARING OF LOWER VAIPITO STREAM MOUTH AND UPSTREAM AREA LABOR Personnel Number Hours Hourly Rate ($) Cost ($) Supervisor 1 16 15 240 Heavy Equip. Operator 1 16 13 208 Laborer 2 16 6 192 All Personnel 4 64 $640 MATERIALS Item Quantity Unit Cost ($) Cost ($) Picks 3 15 45 Sledge Hammers 3 25 75 Shovel 3 22 66 Weed-eaters 3 300 900 Machetes 3 20 60 Garbage Bags 20 boxes 5 100 Wheel Barrows 3 50 150 All Materials $1,396 TOTAL LABOR AND MATERIALS $2,036 Notes: Preliminary estimate assumes use of existing equipment that is owned by the ASG Department of Public Works Source: Pedersen Planning Consultants, 2000

TABLE 6-8 PRELIMINARY COST ESTIMATE PLANTING OF TREES UPSTREAM OF VAIPITO STREAM MOUTH LABOR Personnel Number Hours Hourly Rate ($) Cost ($) ASCC Plant Nursery Technician 1 104 10 1,040 ASCC Field Crew Leader 1 12 8 96 ASCC Field Crew Members 2 12 6 144 All Personnel 4 140 $1,280 MATERIALS Item Quantity Unit Cost ($) Cost ($) Native Riparian Trees 100 3 300 Mangrove Trees 440 5 2,200 Littoral/Coastal Plants 100 5 500 Garbage Bags 20 boxes 5 100 All Materials $3,100 EQUIPMENT Shovels 3 22 66 Machetes 3 20 60 Picks 3 15 45 Wheel Barrows 2 50 100 Weed-eaters 2 300 600 All Equipment $871 TOTAL LABOR AND MATERIALS $5,251 Source: Pedersen Planning Consultants, 2000

Long-Term Monitoring and Site Maintenance Requirements

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-14

Long-term resource management activities associated with the restoration of the lower reach of Vaipito Stream should include the seasonal monitoring of selected resource characteristics and periodic site maintenance.

Resource Monitoring

The process of resource monitoring will involve completion of the following steps by ASEPA, ASCMP, or other ASG agency staff:

Long term monitoring of the Vaipito Stream restoration and enhancement project will require periodic examinations of, at least, the following:

• the presence of stream flow; • potential impedances to stream discharge; • evidence of eroding stream bank areas; • potential failures or damages to gabion baskets or rock walls along the stream bank; • survival of planted, riparian and littoral/coastal vegetation; • potential flood damages to commercial and public facility properties; • changes in land uses immediately adjacent to the stream banks; • point-source discharges, e.g., storm water; and, • changes in the type and number of fish and invertebrates near the stream mouth.

The types of information needed, monitoring frequency, monitoring locations, and evaluation parameters are summarized in Table 6-9. A field work sheet or checklist, which can be used in the field, is provided in Table 6-10.

Future resource monitoring can be effectively performed through bi-annual site visits to lower Vaipito Stream. This approach will enable comparisons during wet (December through March) and dry (April through November) seasons of the year. Additional visits should also take place during and/or following significant stormwater events that may be generated from periods of significant rainfall.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-15 TABLE 6-9 LONG-TERM RESOURCE MONITORING REQUIREMENTS AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN VAIPITO STREAM

Resource Information Monitoring Monitoring Monitoring Evaluation Requirement Frequency Method Location(s) Parameters Wetland/Stream Stream Flow 1 x (Dec-March) Visual observation Vaipito Stream mouth to 650 feet upstream Presence of stream flow or obstructions to stream flow Hydrology 1 x (April-Nov) Wetland Outlet 1 x (Dec-March) Visual observation Vaipito Stream mouth Presence of stream flow or obstructions to stream flow 1 x (April-Nov) Stream Channel Stream channel 1 x (Dec-March) Measure manually, using tape measure Vaipito Stream: 600 feet upstream of wetland Changes in dimensions of stream channel trapezoid cross sections 1 x (April-Nov) at 100-foot intervals Stream Modifications Changes to 1 x (Dec-March) Take digital photos, measure manually Vaipito Stream: 650 feet upstream of wetland Evidence of bank erosion, changes in flow path, or new stream banks 1 x (April-Nov) using tape measure, record type & size, manmade structures along stream bank (e.g., rock walls) locate changes on map, incorporate data into GIS Water Quality Changes in land 1 x (Dec-March) Take digital photos, document type and Within 100 feet of Vaipito Stream segment Do new land uses generate non-point surface or subsurface uses 1 x (April-Nov) estimated size, locate changes on map, discharges into the stream channels? incorporate data into GIS Vegetation Survival of new 1 x (Dec-March) Take visual count of new mangrove Between Vaipito Stream mouth and 650 feet Number of plants that remain vegetation 1 x (April-Nov) propagules, riparian trees, and coastal/ upstream littoral plants. Aquatic Fish Type and number 2 x (Dec-March) Collection of driftnet samples of outgoing10 feet upstream of Vaipito Stream mouth. Changes in diversity and abundance of fish and and Invertebrates of fish and 2 x (April-Nov) larvae for 3-4 hour evening periods. crustaceans. crustaceans (See report narrative for detail.) Molluscs Type and number 2 x (Dec-March) Mark-recapture technology or quadrant 10 feet upstream of Vaipito Stream mouth. Changes in diversity and abundance of molluscs. of molluscs 2 x (April-Nov) counts at night. TABLE 6-10 FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN VAIPITO STREAM PAGE 1 of 3 PAGES Date(s) of field monitoring:______Name(s) of observer(s): Agency/Company Represented:

Vaipito Stream STREAM AND WETLAND HYDROLOGY (Circle "yes" or "no") 1 Is water flowing in the stream (between Vaipito Stream mouth and Route 1)? Yes No 2a Are stream flows discharging into Pago Pago Harbor? Yes No b If no, what appears to be impeding stream discharge? Describe.

STREAM CHANNEL MODIFICATIONS 3 a Has the stream bank been altered and with what material has the alteration been made? Yes No ___ Basaltic rock wall ___ Concrete wall ___ Rock-filled gabions ___ Other, please describe: b If alteration has occurred, locate on field map. _____ Check, when field map is so marked. 4 a Do existing rock walls, concrete walls or gabions appear to have been damaged from past or recent stormwater events? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 5 a Is there evidence of bank erosion? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 6 a Do you see evidence of a change in the stream flow path? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked

CHANGES IN STREAM CHANNEL TRAPEZOID 7 Refer to page 3: For each trapezoid represented, measure the distances between 1) Points A and B, 2) Points C and D, and 3) Points E and F. Write in the measurement on each trapezoid.

SURVIVAL OF NEW WETLAND PLANTS 8 a Count number of surviving new mangrove trees b Count number of surviving new fruit trees c Count number of new coastal plants d Count number of surviving littoral plants

CHANGES IN LAND USE 9 a Document type and number of new land uses within 100 feet of Vaipito Stream channel. Number of facilities: Briefly describe each new facility: Residential Commercial Industrial Public Facility Community Facility Agricultural b Map location of new land uses on field map. ___ Check, when field map is so marked 10 a Do any existing land uses, within 100 feet of the stream channel, appear to have sustained damage from past or recent stormwater events? Yes No b If so, where? (Locate on field map.) ___ Check, when field map is so marked

NON-POINT DISCHARGES INTO STREAM CHANNEL 11 Type of discharges: Briefly describe type of discharge: Piggery Stormwater Cesspool Industrial Commercial 12 Locate discharge on field map ___ Check, when field map is so marked TABLE 6-10 (Continued) FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN VAIPITO STREAM

PAGE 2 of 3 PAGES

FISH AND INVERTEBRATES 13 Identify the type and number of fish observed via the collection of driftnet samples of outgoing larvae collected near Vaipito Stream mouth. Family Genus/Specie Number Observed a Fish

b Crustaceans

MOLLUSCS 14 Identify the type and number of molluscs that were observed by mark-recapture technology or quadrant count near Vaipito Stream mouth. Family Genus/Specie Number Observed TABLE 6-10 (Continued) FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN VAIPITO STREAM

PAGE 3 of 3 PAGES CHANGES IN STREAM CHANNEL TRAPEZOID 7 For each trapezoid represented below, measure the distances between 1) Points A and B, 2) Points C and D, and 3) Points E and F. Write in the measurement on each trapezoid.

Station Vaipito Stream

1+ 00 E AB

C D F

2 + 00 E AB

C D F

3 + 00 E AB

C D F

4 + 00 E AB

C D F

5 + 00 E AB

C D F

6 + 00 E AB

C D F Vehicular and pedestrian access to selected monitoring stations is largely dependent upon the cooperation and authorization of local residents and the Pago Pago Village Council. Assuming that residents cooperatively permit periodic access for long-term resource monitoring, field monitoring should begin at the stream mouth and extend 650 upstream. The establishment of monitoring stations should begin at the stream mouth and continue upstream at 100-foot intervals.

More specific monitoring of stream fauna should be made immediately upstream of the Vaipito Stream mouth. Such monitoring should include the collection of driftnet samples of outgoing larvae, at least two times per month, for 3-4 hour periods in the evening. The driftnets (150- 200 ųm mesh) should be attached to rebar pounded into the stream substrata, or simply suspended from trees or bridges to that the net is at the surface of the water. The samples would subsequently be preserved in ethanol. The type and number of fish and crustaceans should be enumerated using a dissecting microscope. Use of a dissecting microscope will likely require a 2-3 day training class and the necessary equipment.

Molluscs should be monitored by mark-recapture methodology, or quadrant counts at night since most are primarily nocturnal. Some training in these techniques is recommended.

Site Maintenance

Periodic site maintenance should take place within the project area approximately four times per year. Household and commercial wastes along the lower 1,360 feet of Vaipito Stream are expected to represent the primary focus of long-term site maintenance. Various wastes from Pago Pago Harbor will be more evident at the Vaipito Stream mouth. Maintenance of the Vaipito Stream mouth is especially important to ensure adequate tidal exchange and the maintenance of brackish water quality.

A crew of three to four persons will be necessary to periodically walk the 1,360-foot length of lower Vaipito Stream. Such inspections would occur shortly after significant rainfall and stormwater events. Machetes and weed-eaters will be required to periodically trim vegetation along selected portions of the stream channel. The manual collection of solid wastes will also be necessary to minimize obstructions to stream discharge and effective tidal exchange.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Vaipito Stream, Page 6-20 Chapter Seven PAPA STREAM

LOCATION

Papa Stream is generally situated north of Pala Lagoon along the southern coast of the Island of Tutuila (Figure 7-1). The stream segment examined in this study extends about 1,200 feet upstream of Route 1 (Figure 7-2).

STREAM HYDROLOGY

Sources of Surface Runoff

The Leele-Papa-Tauese Stream drainage carries surface runoff from the east and southeast slopes of Leele Mountain to Pala Lagoon. The apex of this drainage begins near at the summit of Leele Mountain near the 1,724-foot contour.

Available 1:200 scale topographic maps for the Island of Tutuila indicate that Leele Stream originates near the 825-foot contour. The confluence of the main stem of Leele Stream and one smaller upland tributary occurs at about the 325-foot elevation. Downstream of this confluence, Leele Stream becomes Papa Stream. Consequently, Papa Stream represents the downstream portion of the Leele-Papa Stream drainage (Figure 7-1).

The 1,200-foot segment of Papa Stream, which is the subject of the Wetland/Stream Restoration and Enhancement Plan, flows through the northern portion of the inhabited Nuuuli Village area (Figure 7-2). The surface runoff from Leele Stream and its upland tributary is the primary contributor of surface runoff to this segment of Papa Stream.

In November 1999, PPC observed that a culvert was installed along the east bank of Papa Stream that enables the transport of runoff from a local road improvement west of Papa Stream, as well as stream discharges of Tauese Stream, to discharge into Papa Stream. The hydrologic connection of Tauese Stream and Papa Stream is not clearly evident on available 1:200 scale topographic maps. U.S. Geological Survey references to the location of one low-flow, partial record station (No. 16944000) confirm that this hydrologic connection between Tauese Stream and Papa Stream has existed for some time (Wong, 1996).

General Stream Characteristics

The 1,200-foot segment of Papa Stream extends from a concrete weir at station 11+80 to a double culvert below Route 1 (Figure 7-2). The concrete weir was associated with a former dam that was constructed to establish a small surface water reservoir.

Cross-sections documented by PPC in November 1999 indicate that the width of the stream segment (between east and west stream banks) ranges between 15 and 33 feet. The depth of the stream channel (between the top of bank to the bottom of the stream bed) is between two and 12 feet along the east side of the stream. Along the west side of the stream, the depth of the stream channel ranges between 2 and 8 feet below the stream bank.

The stream channel bed is composed of exposed basalt and larger boulders, smaller rock cobble, sand, and decomposed organic material. Rock and solid waste material are found within and the along the banks of various portions of the stream.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-1 Figure 7-1 Location Map Leele-Papa-Tauese Stream Drainage

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-2 Figure 7-2 Papa Stream Segment Existing Conditions

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-3 Stream flow, in some cases, is constrained by larger rock and solid waste material that have gradually re-directed the direction of stream flows along some areas within the stream course. These modifications in stream hydrology have, in turn, generated the erosion of stream banks in various locations.

Stream Modifications

Modifications in stream hydrology along Papa Stream are primarily due to past man-made efforts to reduce bank erosion and protect properties adjacent to the stream banks. A few examples are identified in the following paragraphs.

In the vicinity of station 4+00, an 8-foot high rock wall is located about 10 feet west of the west stream bank. This wall was apparently constructed to reduce potential property damages that can be generated from occasional stormwater events. In November 1999, this wall appeared to be in good structural condition and not impacted by past stormwater events.

In November 1999, failing gabion baskets were discovered just downstream of station 11+80 along the west bank of the stream. However, upon return to this area in late June 2000, PPC and ASEPA representatives observed newly constructed stream modifications along the west bank of the stream.

A new 50-foot section of concrete wall, an eight-foot wide section of rock-filled gabions, two terraced gabions, and an 80-foot length of concrete wall were constructed immediately downstream of the concrete weir at station 11+80. This stream modification clearly narrowed the former stream width by about 10- 20 feet. In addition, the installation of concrete wall sections will likely increase the velocity of future stream flows along this reach of Papa Stream. Such modifications can also be expected to generate downstream consequences such as bank erosion and damage to rock-filled gabion baskets.

Immediately upstream of station 11+80, an 8-10 foot length of rock-filled gabions was observed along the east bank of Papa Stream. A local resident informed PPC representatives that this section of rock-filled gabions had remained along the east bank of the stream for about 12 years and effectively protected adjacent residential property from occasional flooding and potential property damage.

During the June 2000 site visit, ASEPA and PPC representatives also investigated a significant stream modification about 700-800 feet upstream of the concrete weir (station 11+80). The construction of a basaltic rock wall along the west bank of Papa Stream in 1998 relocated the main stem of the stream channel east of its former stream path (Galeai, 2000). However, a portion of the former channel remained as a long narrow island was observed approximately 100-150 feet downstream of the basaltic rock wall.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-4

Immediately downstream of these two parallel stream channels, a single main stem was established. However, the stream alteration in this area significantly eroded lands along the east bank of the stream. Informal discussions with the adjoining landowner, George Galeai, as well as uprooted ifi, coconut, and other trees provided ample evidence of the consequences associated with the upstream modification.

Stream Flows

Historical Stream Flows

In 1996, the U.S. Geological Survey (USGS) published an estimated median stream flow for Papa Stream (Table 7-1). The median stream flow estimate was based upon historical stream flow measurements obtained from a continuous-record gage (No. 16944200) that was situated 500 feet downstream of Papa/Tauese Stream confluence between 1966 and 1976. The same gage was occasionally operated as a partial-record site between 1968 and 1983. The highest flow recorded at this stream gage was 1,640 cubic feet per second (cfs) on April 29, 1975. However, USGS reported that stream flows were absent from this stream location for many days of the year.

A low-flow, partial record station (No. 16944000), which was located 0.3 mile upstream of the Papa/Tauese Stream confluence, provided 30 stream measurements between 1959 and 1990. The U.S. Geological Survey estimated a median stream flow of 1.48 cfs at this station location (Wong, 1996).

TABLE 7-1 MEDIAN STREAM FLOW ESTIMATE PAPA STREAM

Stream USGS Gage Location Stream Flow Estimated Median Gage Measurements Flow (cfs) Station (number) Papa Stream 169442000 500 feet downstream from Continuous 1.30 Papa/Tauese Stream intermittently confluence between 1966-1976 Papa Stream 16944000 0.3 mile upstream of Papa/ 30 1.48 Tauese Stream confluence

Source: Wong, 1996

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-5 Stormwater Discharges and Related Flood Potential

In 1999, Pedersen Planning Consultants recently made a hydrologic analysis of potential stormwater discharges into Pala Lagoon that could be generated from a range of storm events (Pedersen Planning Consultants, 2000). Through hydrologic modeling, PPC determined that potential stormwater discharges into the Pala Lagoon can range from 739 cubic feet per second (cfs) for a 2-year storm and about 2,072 cfs for a 100-year storm. Consequently, significant stream flows can be carried by Papa Stream for more common 2-year events, as well as less frequent 100-year storms.

TABLE 7-2 STORMWATER DISCHARGES FROM PAPA STREAM INTO PALA LAGOON 2,10,50, AND 100-YEAR STORM EVENTS IN CUBIC FEET PER SECOND (CFS)

Location 2-Year Storm 10-Year Storm 50-Year Storm 100-Year Storm Papa Stream 739 1,134 1,847 2,072

Source: Pedersen Planning Consultants, 2000

In November 1999, PPC also gathered cross-sectional data along the 1,200-foot Papa Stream segment to assess the capability of this stream segment to accommodate these stormwater events. Cross sections were recorded at 100-foot intervals along this stream segment.

With the application of hydrologic modeling, PPC determined that potential stormwater flows are much larger than the capacity of the stream at each cross-section (Table 7-3). One important exception is the bridge culverts underneath Route 1 (station 1+00), which can accommodate stormwater flows of about 2,162 cfs. Consequently, the culverts underneath Route 1 can support potential flows from a 100-year storm event.

TABLE 7-3 CROSS-SECTIONAL ANALYSIS ALONG PAPA STREAM SEGEMENT

Maximum Stream Flow Slope of Stream Through Cross Section Station (percent) (cfs) 1+00 1.0 2,162 2+00 1.0 380 3+00 1.4 420 4+00 1.5 607 5+00 2.0 344 6+00 1.2 153 7+00 1.1 222 8+00 1.2 321 9+00 1.9 629 10+00 1.6 513 11+00 1.5 332 11+80 1.3 292

Source: Pedersen Planning Consultants, 2000

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-6 During its November 1999 survey, PPC representatives informally met with Mr. Aiakopu Samuelo, a matai of Nuuuli Village and an ASG Department of Public Works road supervisor. Mr. Samuelo, who has lived in Nuuuli for 48 years, recalled his personal observations of flood waters up to four feet above the top of the stream bank near station 4+00.

The potential flood plain associated with a 100-year storm event in Nuuuli was mapped by the Federal Emergency Management Agency (FEMA) in May, 1991. Available flood insurance rate maps prepared by FEMA suggest that residential properties along the east and west banks of the Papa Stream segment could be flooded from a 100-year storm event.

VEGETATION

November 1999 Survey

Art Whistler of Isle Botanica conducted a botanical survey of the Papa Stream segment on November 5, 1999 (Figure 7-2). Mr. Whistler was part of a three-person field survey team organized by Pedersen Planning Consultants that observed wetland vegetation, habitat for aquatic fish and invertebrates, stream hydrology, as well as land uses within and adjacent to the wetland. His observations are summarized in the following paragraphs.

The vegetation of Papa Stream was comprised of plants growing along the stream banks. The dominant trees along the Papa Stream segment included ifi (Tahitian chestnut), falaga (Barringtonia samoensis), afa (Neonauclea forsteri), laupata (Macaranga harveyana), ulu (breadfruit), and mango. Underneath these trees, the ground cover was dominated by wetland plants such as California grass, Job’s tears, and mile-a-minute vine. Lesser amounts of willow primrose, (Ludwigia octovalis) and Centosteca lappacea, Kyllinga nemoralis, beggar’s-tick (Bidens alba), and basket grass were also observed. Vegetation along Papa Stream

Vegetation Trends

No prior studies of the vegetation of Papa Stream have been conducted. Consequently, no correlation can be made concerning historical vegetative trends.

The continued use of the adjoining lands for established residential use suggests that existing vegetation will generally remain the same. At the same time, the planting of more trees such as banana and breadfruit is probable as residents supplement their diets with these traditional crops.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-7 AQUATIC FISH AND INVERTEBRATES

General

On November 5, 1999, Charles Chong of the PPC field survey team made observations of aquatic fish and invertebrates along the 1,200-foot segment of Papa Stream. His observations are summarized in the following paragraphs.

This segment of Papa Stream contained habitat that primarily represented shallow riffle with a cobble substrata.

At the upstream end of the stream segment, there is a small, concrete weir that extends across the entire width of the stream bed (station 11+80). In this location, there was a periphyton complex of Cladophora and Spirogyra covering the rocks. The presence of Cladophora and Spirogyra was, in part, due to the open canopy at this site. No solid waste material was observed.

Downstream of the concrete dam structure, the stream was heavily polluted with household garbage. There was visual evidence that this solid waste material had been dumped by some residents living adjacent to the stream.

Fish

Two species of Stiphodon and two species of Sicyopterus were abundant in Papa Stream. Kuhlia spp. were common, but no anguillids were observed during the survey. Although gobies were well represented, other macrofaunal organisms were absent.

Invertebrates

Macrobrachium lar was the only crustacean documented in the stream. No neritids were observed along the stream segment. The lack of some species may have been due to elevational preferences of some organisms. Some organisms may be present at higher elevations of Papa Stream, Leele Stream, and Tauese Stream.

There may be many factors that favor gobies over other taxa in Papa Stream. Long-term monitoring at various elevations is needed to explain the abundance and diversity of organisms in this stream.

Relative Abundance and Diversity of Fish and Invertebrates

A site specific summary of macrofaunal organisms observed during the survey are summarized in Table 7-4. Genera are listed in order of descending abundance within their taxonomic group.

TABLE 7-4 SUMMARY OF MACROFAUNAL ORGANISMS OBSERVED ALONG PAPA STREAM

Stream Location Fishes Crustaceans Molluscs Former Navy weir site Sicyopterus (2 spp.) Macrobrachium None (approximately 1,180 feet Stiphodon (2 spp.) upstream of Route 1 stream Kuhlia crossing)

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-8 Source: Chong, 2000 The relative abundance and diversity of fish and invertebrates along Papa Stream is summarized in Table 7-5. The characterization of relative abundance and diversity reflects a general comparison of the abundance and diversity of fish and invertebrates observed at one Papa Stream site with all 10 sites evaluated for the Wetland/Stream Restoration and Enhancement Plan. Papa Stream contained the highest density and diversity of gobies that was observed at all of the 10 sites.

TABLE 7-5 RELATIVE ABUNDANCE AND DIVERSITY OF FISH AND INVERTEBRATES PAPA STREAM Fishes Crustaceans Molluscs Abundance High Medium Low Diversity High Low Low

Source: Pedersen Planning Consultants, 2000

LAND USES ADJACENT TO PAPA STREAM

Papa Stream is situated within an upland residential area of Nuuuli Village. Approximately 11 single family homes are constructed immediately adjacent to the east and west banks of the stream. Vehicular roads and trails from Route 1 provide access to these homes.

A few piggeries were also located near the banks of the stream. In some cases, wastewater from these piggeries discharged into Papa Stream.

Station 1+00 is located below Route 1 roadway corridor. This area contains a variety of commercial retail establishments.

Solid waste discarded from the 11 residences poses the greatest impact upon stream hydrology and aquatic habitat. The amount of solid waste material in various locations prevented the flow of surface runoff along the main stem of the stream.

RIPARIAN RESTORATION AND ENHANCEMENT OPPORTUNITIES

General

Three opportunities were identified for the restoration and enhancement of lower Papa Stream. The scope of these restoration and enhancement opportunities, and related implementation strategies, are presented in the following paragraphs. The potential benefits and impacts derived from the implementation of the recommended strategies are subsequently evaluated and compared in the following paragraphs.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-9 Opportunities and Strategies

Option 1: Clean Papa Stream and Enhance Riparian Vegetation

The initial action associated with Option 1 is a significant cleanup of lower Papa Stream. The cleanup should be made between the concrete weir at station 11+80 and the Route 1 crossing over Papa Stream.

This effort will require the collection and disposal of a wide variety and large volume of solid waste materials. Manual collection will be sufficient to collect much of this material. However, the use of a backhoe, front-end loader, or “cherry picker” will be necessary to retrieve some larger materials that have been indiscriminately dumped into the stream bed. Larger dump trucks will be required to haul larger materials to the Futiga landfill.

One of the greater challenges of this initial effort will be to mobilize heavy equipment at selected locations along the stream bank. Available equipment from either the American Samoa Power Authority or the American Samoa Department of Public Works should be requested and used to support the cleanup effort.

Following the initial stream cleanup, the American Samoa Community College, Land Grant Program should initiate the planting of about 300 native riparian trees along the banks of Papa Stream. This planting should include a combination of ifi (Tahitian chestnut) fau, laufala, and falaga tree seedlings. The planting of more native riparian trees along Papa Stream represents an important resource management opportunities because these native riparian trees have roots that can help stabilize the soil on the banks of the stream. Propagated seedlings of these native trees may already be available at the ASCC Land Grant Program nursery.

The ASCC Land Grant Program would encourage residents to participate in the planting of these trees along the east and west banks of the stream. ASCC Land Grant has considerable experience with encouraging community participation through its Forestry Stewardship Program. Colin Steele, ASCC/AHNR Project Forester, envisions that the enhancement of riparian vegetation and related participation of residents can best be accomplished by providing, at no charge, a total of 30 tree seedlings to each household along the stream. However, the “no charge” arrangement would be conditional to the resident’s agreement to plant the new trees within 30 feet of the stream bank (Steele, 1995). Consequently, random wetland tree plantings would be made along the east and west sides of the 1,200-foot stream segment.

Option 2: Clean Stream, Improve Stream Hydrology, and Reduce Bank Erosion

The initial action associated with Option 2 is a significant cleanup of lower Papa Stream. The cleanup should be made between the concrete weir at station 11+80 and the Route 1 crossing over Papa Stream.

Incoming stream flows from Tauese Stream discharge into Papa Stream via a 3-foot wide, concrete culvert. This culvert is situated between stations 5+00 and 6+00. Under full flow conditions, the culvert can convey approximately 140 cfs of stormwater runoff at a velocity of about 18 feet per second. The angle of flow introduction to Papa Stream and occasional higher

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-10 flow velocities have apparently generated excessive erosion along the east bank of Papa Stream and littered the stream bed with considerable amounts of rock and debris.

Due to the erosive nature of soils along the stream bank, aggressive bank stabilization practices should be used to help improve stream hydrology and reduce the amount of future stream bank erosion. While various construction options are available, it recommended that the east bank of Papa Stream be armored with basaltic rock and grouted with a concrete slurry along the upstream and downstream sides of the Tauese Stream discharge (Figure 7-3). This approach will enable the construction of a strong bank structure without increasing the velocity of downstream stream flows.

Option 3: Restore Stream Path Upstream of Project Area

Option 3 would design and construct stream improvements that would:

• restore the former single, stream path some 700 to 800 feet upstream of station 11+80; • somewhat reduce stream velocities downstream of the basaltic wall that has generated significant downstream bank erosion; • reduce further downstream bank erosion along east and west banks of Papa Stream; and, • provide potential opportunities for planting wetland trees such as ifi along the 100-150-foot length of the stream bank that has been impacted by stream modification.

ASEPA/ASDOC would need to retain a professional engineer to design conceptual, preliminary, and final construction drawings, as well as preliminary cost estimates, for this stream improvement project. Once funds are secured for this project, a building contractor would be selected for construction of the proposed design.

Comparative Benefits and Impacts

PPC’s evaluation of the three alternate restoration and enhancement strategies is summarized in Table 7-6. Option 1 provides somewhat greater benefits to wetland vegetation and fish and invertebrate habitat for a reasonable cost. Option 2 provides some needed improvements between station 5+00 and 6+00 that would help reduce bank erosion and potential flooding along a portion of lower Papa Stream.

Option 3 would address a significant bank erosion and stream hydrology upstream of the project area. This project would provide some benefits to wetland vegetation, as well as fish and invertebrate habitat. However, the potential significant cost associated with this project makes this project less desirable despite its need. TABLE 7-6 COMPARATIVE EVALUATION WETLAND RESTORATION AND ENHANCEMENT OPPORTUNITIES LOWER PAPA STREAM Option Project Residential Subsistence Fish & Wetland/ Stream Flood Hazards Cost Land Uses Agriculture Invertebrate Riparian Bank & Property Habitat Vegetation Stability Damage 1 LC LB NBC MB SB NBC LB 2 MC NBC NBC MB LB NBC MB 3 SC MB NBC LB LB NBC LB Notes: Potential project benefits were rated by PPC as follows: SB Significant project benefits LC Limited undesirable consequences MB Moderate project benefits MC Moderate undesirable consequences LB Limited project benefits SC Significant undesirable project impacts NBC No anticipated project benefits or undesirable consequences Source: Pedersen Planning Consultants, 2000

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-11

Figure 7-3 Option 2: Reduction of Erosion at East Bank of Papa Stream

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-12 Recommended Option and Estimated Project Cost

The cleaning of the 1,200-foot segment of Papa Stream and the planting of additional riparian vegetation (Option 1) is recommended for implementation. This wetland restoration project is recommended because the project can enhance wetland vegetation, as well as fish and invertebrate habitat.

The costs associated with this project would primarily be associated with the initial clearing, removal and disposal of solid waste material from the lower reach of Papa Stream. The subsequent collection and planting of ifi, fau, laufala, and falaga tree cuttings would be carried out by the ASCC Land Grant Program.

The estimated cost associated with the initial clearing of the 1,200-foot segment of Papa would be $3,626 (Table 7-7). The planting of native riparian trees would cost an estimated $3,348 (Table 7-8). Consequently, the total project is expected to cost approximately $6,974.

TABLE 7-7 PRELIMINARY COST ESTIMATE CLEARING OF LOWER PAPA STREAM MOUTH

LABOR Personnel Number Hours Hourly Rate ($) Cost ($) Supervisor 1 40 15 600 Heavy Equip. Operator 1 40 13 520 Laborer 4 40 6 960 All Personnel 6 240 $2,080 MATERIALS Item Quantity Unit Cost ($) Cost ($) Picks 3 15 45 Sledge Hammers 3 25 75 Shovel 3 22 66 Weed-eaters 3 300 900 Machetes 3 20 60 Garbage Bags 50 boxes 5 250 Wheel Barrows 3 50 150 All Materials $1,546

TOTAL LABOR AND MATERIALS $3,626 Notes: Preliminary estimate assumes use of existing equipment owned by the ASG Department of Pubic Works

Source: Pedersen Planning Consultants, 2000

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-13 TABLE 7-8 PRELIMINARY COST ESTIMATE PROPAGATION AND PLANTING OF NATIVE RIPARIAN TREES LOWER PAPA STREAM LABOR Personnel Number Hours Hourly Rate ($) Cost ($) ASCC Plant Nursery Technician 1 104 10 1,040 ASCC Field Crew Leader 1 24 8 192 ASCC Field Crew Members 2 24 6 288 All Personnel 4 176 $1,520 MATERIALS Item Quantity Unit Cost ($) Cost ($) Native Riparian Trees 300 3 900 Garbage Bags 40 boxes 5 200 All Materials $1,100 EQUIPMENT Shovels 3 22 66 Machetes 3 20 60 Picks 3 15 45 Wheel Barrows 2 50 100 Weed-eater 1 300 300 All Equipment $571

TOTAL LABOR AND MATERIALS $3,191 Notes: Preliminary estimate assumes use of existing equipment owned by the ASG Department of Public Works

Source: Pedersen Planning Consultants, 2000

Long-Term Monitoring and Site Maintenance Requirements

Long-term resource management activities associated with the restoration of the lower reach of Papa Stream should include the seasonal monitoring of selected resource characteristics and periodic site maintenance.

Resource Monitoring

The process of resource monitoring will involve completion of the following steps by ASEPA, ASCMP, or other ASG agency staff:

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-14 Long term monitoring of the Papa Stream restoration and enhancement project will require periodic examinations of, at least, the following:

• the presence of stream flow; • potential impedances to stream discharge; • evidence of eroding stream bank areas; • potential failures or damages to gabion baskets or rock walls along the stream bank; • survival of planted, riparian trees; • potential flood damages to commercial and public facility properties; • changes in land uses immediately adjacent to the stream banks; • point-source discharges, e.g., storm water; and, • changes in the type and number of fish and invertebrates near station 1+00.

The types of information needed, monitoring frequency, monitoring locations, and evaluation parameters are summarized in Table 7-9. A field work sheet or checklist, which can be used in the field, is provided in Table 7-10.

Future resource monitoring can be effectively performed through bi-annual site visits to lower Papa Stream. This approach will enable comparisons during wet (December through March) and dry (April through November) seasons of the year. Additional visits should also take place during and/or following significant stormwater events that may be generated from periods of significant rainfall.

Vehicular and pedestrian access to selected monitoring stations is largely dependent upon the cooperation and authorization of local residents and the Nuuuli Village Council. Assuming that residents cooperatively permit periodic access for long-term resource monitoring, field monitoring should begin at the station 1+00 and extend 1,180 feet upstream. Future measurements of changes in the stream channel trapezoid will require the continued use of the same stream cross section stations used for the present study.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-15 TABLE 7-9 LONG-TERM RESOURCE MONITORING REQUIREMENTS AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN PAPA STREAM

Resource Information Monitoring Monitoring Monitoring Evaluation Requirement Frequency Method Location(s) Parameters Wetland/Stream Stream Flow 1 x (Dec-March) Visual observation Station 1+00 through Station 11+80 Presence of stream flow or obstructions to storm flow Hydrology 1 x (April-Nov) Stream Channel Stream channel 1 x (Dec-March) Measure manually, using tape measure Papa Stream: 1180 feet upstream of Station Changes in dimensions of stream channel trapezoid cross sections 1 x (April-Nov) 1+00 at 100-foot intervals Stream Modifications Changes to 1 x (Dec-March) Take digital photos, measure manually Papa Stream: 1180 feet upstream of Station Evidence of bank erosion, changes in flow path, or new stream banks 1 x (April-Nov) using tape measure, record type & size, 1+00 manmade structures along stream bank (e.g., rock walls) locate changes on map, incorporate data into GIS Water Quality Changes in land 1 x (Dec-March) Take digital photos, document type and Within 100 feet of Papa Stream banks Do new land uses generate non-point surface or subsurface uses 1 x (April-Nov) estimated size, locate changes on map, discharges into the stream channel? incorporate data into GIS Vegetation Survival of new 1 x (Dec-March) Take visual count of new riparian trees Stream banks between Station 1+00 and Number of plants that remain vegetation 1 x (April-Nov) Station 11+80 Aquatic Fish Type and number 2 x (Dec-March) Collection of driftnet samples of outgoing 10 feet upstream of Station 1+00. Changes in diversity and abundance of fish and and Invertebrates of fish and 2 X (April-Nov) larvae for 3-4 hour evening periods. crustaceans. crustaceans (See report narrative.) Molluscs Type and number 2 x (Dec-March) Mark-recapture technology or quadrant 10 feet upstream of Station 1+00. Changes in diversity and abundance of molluscs. of molluscs 2 X (April-Nov) counts at night. TABLE 7-10 FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN PAPA STREAM

PAGE 1 of 3 PAGES Date(s) of field monitoring:______Name(s) of observer(s): Agency/Company Represented:

Papa Stream STREAM AND WETLAND HYDROLOGY (Circle "yes" or "no".) 1 Is water flowing in the stream between Station 1+00 and Station 11+80? Yes No 2a Are stream flows continuing immediately downstream of Station 1+00? Yes No b If no, what appears to be impeding stream discharge? Describe.

CHANGES IN STREAM CHANNEL TRAPEZOID 7 Refer to page 2: For each trapezoid represented, measure the distances between 1) Points A and B, 2) Points C and D, and 3) Points E and F. Write in the measurement on each trapezoid.

SURVIVAL OF NEW RIPARIAN PLANTS 8 Count number of surviving new riparian trees

CHANGES IN LAND USE 9 a Document type and number of new land uses within 100 feet of stream channel. Number of facilities: Briefly describe each new facility: Residential Commercial Industrial Public Facility Community Facility Agricultural b Map location of new land uses on field map. ___ Check, when field map is so marked 10 a Do any existing land uses, within 100 feet of the stream channel, appear to have sustained damage from past or recent stormwater events? Yes No b If so, where? (Locate on field map.) ___ Check, when field map is so marked

NON-POINT DISCHARGES INTO STREAM CHANNEL 11 Type of discharges: Briefly describe type of discharge: Piggery Stormwater Cesspool Industrial Commercial 12 Locate discharge on field map ___ Check, when field map is so marked TABLE 7-10 (Continued) FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND AND ENHANCEMENT PLAN PAPA STREAM PAGE 2 of 3 PAGES

FISH AND INVERTEBRATES 13 Identify the type and number of fish and crustaceans observed via the collection of driftnet samples of outgoing larvae. Family Genus/Specie Number Observed a Fish

b Crustaceans

MOLLUSCS 14 Identify the type and number of molluscs that were observed by mark-recapture technology or quadrant count. Family Genus/Specie Number Observed TABLE 7-10 (Continued) FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN PAPA STREAM

CHANGES IN STREAM CHANNEL TRAPEZOID PAGE 3 of 3 PAGES 7 For each trapezoid represented below, measure the distances between 1) Points A and B, 2) Points C and D, and 3) Points E and F. Write in the measurement on each trapezoid.

Station PAPA STREAM Station PAPA STREAM

1+ 00 E 8 +00 E ABAB

C D C D FF

2 + 00 E 9+00 E ABAB

C D C D FF

3 + 00 E 10+00 E ABAB

C D C D FF

4 + 00 E 11+00 E ABAB

C D C D FF

5 + 00 E 11+80 E ABA

C D C D FF

6 + 00 E AB

C D F

7 + 00 E AB

C D F More specific monitoring of stream fauna should be made along Papa Stream in the vicinity of the station 1+00. Such monitoring should include the collection of driftnet samples of outgoing larvae, at least two times per month, for 3-4 hour evening periods. The driftnets (150-200 ųm mesh) should be attached to rebar pounded into the stream substrata, or simply suspended from trees or bridges to that the net is at the surface of the water. The samples would subsequently be preserved in ethanol. The type and number of fish and crustaceans should be enumerated using a dissecting microscope. Use of the dissecting microscope will likely require a 2-3 day training class and the necessary equipment.

Molluscs should be monitored by mark-recapture methodology, or quadrant counts at night since most are primarily nocturnal. Some training in these techniques is recommended.

Site Maintenance

The initial cleanup of lower Papa Stream will represent an important first step toward long- term stream enhancement. However, the initial cleanup is of limited benefit if it is not associated with the implementation of a long-term maintenance strategy.

Periodic site maintenance should take place along lower Papa Stream approximately four times per year. Household wastes along the 1,200 feet of Papa Stream (station 1+00 through station 12+00) are expected to represent the primary focus of long-term site maintenance.

A crew of 10 persons will be necessary to periodically collect and remove discarded solid waste material from the 1,200-foot segment of Papa Stream. Periodic cleanups would occur shortly after significant rainfall and stormwater events. Machetes and a weed-eater will be required to periodically trim vegetation along selected portions of the stream channel.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Papa Stream, Page 7-20 Chapter Eight SAUINO STREAM

LOCATION

Sauino Stream is generally situated north of Pala Lagoon along the southern coast of the Island of Tutuila (Figure 8-1). A 600-foot long segment of Sauino Stream is examined in this study. This segment is situated south of Route 1 and about 330 feet upstream of the Sauino Stream mouth (Figure 8-2).

STREAM HYDROLOGY

Sources of Surface Runoff

Sauino Stream and two unnamed tributaries carry a portion of the surface runoff that drains from south slopes of Leele Mountain. Sauino Stream originates at about the 1,000-foot contour and meanders through the middle of Nuuuli Village before discharging into Pala Lagoon.

An unnamed tributary east of the main stem of Sauino Stream begins near the 600-foot elevation. This tributary carries surface runoff from the west side of Suaavamuli Ridge and joins the main stem of Sauino Stream at about the 40-foot contour.

A third small tributary extends from Deluxe Cafe along Route 1 to its confluence with the main stem of Sauino Stream near the eight-foot elevation. A portion of this tributary represents the 600-foot segment investigated for this study.

General Stream Characteristics

Downstream of Route 1, the small Sauino Stream tributary channel is characterized by a combination of basaltic rock and a man-made, earth lined channel. Smaller rock, cobble, sand, muck, and decomposed organic material comprise the bottom of the stream channel.

Cross-sections documented by PPC in November 1999 indicate that the width of the stream segment (between east and west stream banks) ranges between five and 24 feet. The depth of the stream channel (between the top of bank to the bottom of the stream bed) along the north side of the stream tributary is between 2.5 and four feet. Along the south side of the tributary, the depth of the stream channel ranges between 2.5 and five feet below the stream bank.

While some solid waste material was found discarded along the 600-foot stream segment in November 1999, the type and volume of wastes did not appear to impede stream flow. Larger surface flows generated from stormwater events can easily overtop the stream banks and spread into adjoining residential and agricultural land areas.

Stream Modifications

The 600-foot segment of Sauino Stream was modified by local residents in the late 1990’s to help prevent property damage associated with occasional flooding in the residential area (Fanene, 1999). No rock-filled gabions or other bank stabilization structures were observed along the stream channel in November 1999.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-1 Figure 8-1 Location Map Sauino Stream Drainage

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-2 Figure 8-2 Sauino Stream Segment Existing Conditions

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-3 Stream Flows

Historical Stream Flows

In 1996, the U.S. Geological Survey (USGS) published an estimated median stream flow of 0.25 cubic feet per second (cfs) for Sauino Stream (Table 8-1). The median stream flow estimate was based upon historical stream flow measurements obtained from 17 intermittent stream flow measurements taken from a low-flow, partial-record station (No. 16942000) between 1959 and 1975. This station was situated approximately 0.6 mile upstream from the Sauino Stream mouth (Wong, 1996).

TABLE 8-1 MEDIAN STREAM FLOW ESTIMATE SAUINO STREAM

Stream USGS Gage Location Stream Flow Estimated Gage Measurements Median Flow Station (number) (cfs) Sauino Stream 16942000 0.6 mile upstream of Continuous intermittently 0.25 Sauino Stream mouth between 1959-1975

Source: Wong, 1996

Stormwater Discharges and Related Flood Potential

In 1999, Pedersen Planning Consultants made a hydrologic analysis of potential stormwater discharges into Pala Lagoon that could be generated from a range of storm events (Pedersen Planning Consultants, 2000). Through hydrologic modeling, PPC determined that potential stormwater discharges into the Pala Lagoon can range from 278 cubic feet per second (cfs) for a 2-year storm and about 777 cfs for a 100-year storm (Table 8-2).

TABLE 8-2 STORMWATER DISCHARGES FROM SAUINO STREAM INTO PALA LAGOON 2,10,50, AND 100-YEAR STORM EVENTS IN CUBIC FEET PER SECOND (CFS)

Location 2-Year Storm 10-Year Storm 50-Year Storm 100-Year Storm

Sauino Stream 278 427 693 777

Source: Pedersen Planning Consultants, 2000

In November 1999, PPC also gathered cross-sectional data along the 600-foot Sauino Stream segment to assess the capability of this stream segment to accommodate these stormwater events. Cross sections were recorded at 100-foot intervals along this stream segment.

With the application of hydrologic modeling, PPC determined that the maximum flow capacity of Sauino Stream is 279 cubic feet per second (cfs). When compared with potential stormwater discharges for a 2, 10, 50, and 100-year storm events, it is clear that stormwater flows greater than a 2-year storm would exceed the capacity of Sauino Stream.

The potential flood plain, associated with a 100-year storm event in Nuuuli, was mapped by the Federal Emergency Management Agency (FEMA) in May 1991. Available flood insurance rate maps prepared by FEMA suggest that residential properties along the north and south banks of the 600-foot Sauino Stream segment could be flooded from a 100-year storm event.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-4 VEGETATION

November 1999 Survey

Art Whistler of Isle Botanica conducted a botanical survey of the lower Sauino Stream segment on November 5, 1999. Mr. Whistler was part of a three-person field survey team organized by Pedersen Planning Consultants that observed wetland vegetation, habitat for aquatic fish and invertebrates, stream hydrology, as well as land uses within and adjacent to the wetland. His observations are summarized in the following paragraphs.

The vegetation along the 600-foot Sauino Stream differs considerably between the north and south sides of the stream channel.

Vegetation along the south side of the channel contained maintained grasses such as vaolima (T-grass) and Kyllinga brevifolia. Lesser amounts of carpet grass (Axonopus compressus), Alternanthera sessilis, and Kyllinga nemoralis. A smaller banana plantation was also adjacent to the south side of the channel. None of the grass or tree species were obligate or facultative wetland plants.

The north side of the stream channel resembled more of a wetland environment. This area was dominated by California grass, Job’s tears, T-grass, and Merremia umbellata. Job’s tears and California grass are both facultative wetland species.

Vegetation Trends

Prior studies of the vegetation of along lower Sauino Stream were conducted by Biosystems Analysis, Inc. A brief mention was made of a “hummocky area” between South Pacific Traders (now Laufou Shopping Center) and Lion’s Park.

Within a species checklist, botanists noted that the “hummocky area” was dominated primarily by vaolima (T-grass) and Merremia umbellata. Drier margins were dominated by beggar’s-tick (Bidens alba) and a sensitive plant vao fefe (Mimosa pindica). No meaningful correlation can be made concerning historical vegetative trends since the more general location of the “hummocky area” is not comparable to the more specific stream segment along Sauino Stream. However, it is interesting to note that both vaolima (T-grass) and Merremia umbellata were identified by both surveys.

In the absence of other plantings, the continued maintenance of grasses along the south side of the 600-foot stream segment will likely maintain the presence of existing grasses. The north side of the channel may also continue to support California grass and Job’s tears unless banana plantations are established. Residential expansion is not expected in light of the flood potential in the vicinity of the stream segment.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-5 AQUATIC FISH AND INVERTEBRATES

General

On November 5, 1999, Charles Chong of the PPC field survey team made observations of aquatic fish and invertebrates along the 600-foot segment of lower Sauino Stream. His observations are summarized in the following paragraphs.

This segment of Sauino Stream represented a relatively narrow, earth-lined channel. A stream flow of about one to two cfs was observed during the survey. Rainfall had occurred during, at least, one day prior to the survey.

Dragon/damsel flies (Odonates) were abundant. These introduced insects may be considered important for stream integrity (Steele, 2000).

Fish

Two species of fish were abundant along the stream channel. These species included Poecilia mexicana and Poecilia reticulata.

Invertebrates

No crustaceans were documented along the entire stream channel segment.

In American Samoa, each watershed is unique and can be expected to contain different aquatic organisms. The variation depends upon surface water flow regimes, water quality, and other geophysical characteristics. With perennial, unimpeded stream flow to the ocean, the wetland could possibly include some or all of the type of aquatic animals summarized in Appendix B.

Relative Abundance and Diversity of Fish and Invertebrates

A site specific summary of macrofaunal organisms observed during the survey are summarized in Table 8-3. Genera are listed in order of descending abundance within their taxonomic group.

TABLE 8-3 SUMMARY OF MACROFAUNAL ORGANISMS OBSERVED ALONG SAUINO STREAM

Stream Location Fishes Crustaceans Molluscs 600-foot stream segment Poecilia (2 spp.) None None

Source: Chong, 2000

The relative abundance and diversity of fish and invertebrates along the lower Sauino Stream segment is summarized in Table 8-4. The characterization of relative abundance and diversity reflects a general comparison of the abundance and diversity of fish and invertebrates observed along the Sauino Stream segment with all 10 sites evaluated for the Wetland/Stream Restoration and Enhancement Plan.

The abundance and diversity of fish and molluscs were lower compared to the other 10 sites investigated for the study.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-6 TABLE 8-4 RELATIVE ABUNDANCE AND DIVERSITY OF FISH AND INVERTEBRATES LOWER SAUINO STREAM SEGMENT

Fishes Crustaceans Molluscs Abundance Low None Low Diversity Low None Low

Source: Pedersen Planning Consultants, 2000

LAND USES ADJACENT TO LOWER SAUINO STREAM

The lower Sauino Stream segment is situated within a low-density residential area of Nuuuli Village. Approximately five single family homes are constructed immediately adjacent to the north and south banks of the stream. One smaller banana plantation is located along the south side of the 600-foot, stream channel segment.

RIPARIAN RESTORATION AND ENHANCEMENT OPPORTUNITIES

General

Two opportunities were identified for the restoration and enhancement of lower Sauino Stream segment. The scope of these restoration and enhancement opportunities, and related implementation strategies, are presented in the following paragraphs. The potential benefits and impacts derived from the implementation of the recommended strategies are subsequently evaluated and compared in the following paragraphs.

Opportunities and Strategies

Option 1: Construct a Detention Pond

Option 1 would incorporate the 600-foot stream segment within a larger, 9.1-acre detention pond area (Figure 8-3). The intent of this option would primarily be to detain larger stormwater flows that can occasionally inundate portions of the adjoining residential area and reduce the amount of sediment discharge into Pala Lagoon. Secondarily, the project objective would be to establish more wetland vegetation in the vicinity of lower Sauino Stream. However, no new vegetation would be planted along the 600-foot stream segment.

Construction of the detention area would initially require the excavation of the project area to the 2.5-foot contour. Roughly five to six feet of soil would be excavated from the proposed detention area.

A five to six-foot high way would be constructed along the perimeter of the detention pond. The pond perimeter would extend approximately 4,250 feet. The wall would be constructed through the use of small bags of cement that would be hand-carried and placed along the pond perimeter. The maximum slide slope of the pond interior would contain a 4:1 slope.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-7

Figure 8-3 Option 1: Construction of Detention Pond

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-8 The wall would be back-filled with native soil to reduce the visual impact of the concrete bags, as well as afford the opportunity to plant ifi, other wetland trees, and some fruit trees. Trees would be planted immediately adjacent to the pond perimeter along a 20-foot wide buffer. Wetland and fruit trees would further enhance the attractiveness of the detention area and increase wetland vegetation in the vicinity of the stream. Planting of the wetland and fruit trees would be accomplished by the ASCC Land Grant Program.

A coral trail within the detention pond would enable pedestrian access within the adjoining residential area, as well as access to nearby commercial and recreational areas.

Option 2: Plant Native Riparian Trees Along Stream Banks

Option 2 would focus more specifically upon the 600-foot stream segment (Figure 8-4). Along the north and south stream banks, the American Samoa Community College, Land Grant Program should initiate the planting of ifi (Tahitian chestnut) fau, laufala, and falaga. However, no trees would be planted between the south stream bank and the existing banana plantation.

The establishment of Tahitian chestnut and other native riparian trees along the stream bank represents an important opportunity because these trees contains roots that can help stabilize the soil along the banks of the stream segment. Propagated seedlings of these native trees may already be available at the ASCC Land Grant Program nursery.

The ASCC Land Grant Program would encourage residents to participate in the planting of these trees along the north and south banks of the stream. ASCC Land Grant has considerable experience with encouraging community participation through its Forestry Stewardship Program. Colin Steele, director of the Land Grant Program, envisions that the establishment of native riparian trees and the related participation of residents can best be accomplished by providing, at no charge, a total of 30 tree seedlings to each household along the stream. However, the “no charge” arrangement would be conditional to the resident’s agreement to plant the new trees within 30 feet of the stream bank (Steele, 1995). Consequently, random riparian tree plantings would be made along the north and south sides of the 600-foot stream segment.

Comparative Benefits and Impacts

PPC’s evaluation of the two alternate restoration and enhancement strategies is summarized in Table 8-5.

Option 1 provides a significant opportunity for stormwater detention opportunity, as well as the reduction of flood hazards and property damages. This option would also provide limited enhancement of riparian vegetation in the vicinity of Sauino Stream. At the same time, this project would generate the loss of some limited subsistence agriculture and would require a significant public expenditure for project implementation.

Option 2 would significantly improve riparian vegetation, help stabilize stream banks, and reduce the transport of sediments into Pala Lagoon for a nominal project cost. This project would not impact adjoining residential land uses or subsistence agricultural production.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-9 FIGURE 8-5 OPTION 2: PLANT NATIVE RIPARIAN TREES ALONG STREAM BANKS

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-10 TABLE 8-5 COMPARATIVE EVALUATION RIPARIAN RESTORATION AND ENHANCEMENT OPPORTUNITIES LOWER SAUINO STREAM SEGMENT

Notes: Potential project benefits were rated by PPC as follows: SB Significant project benefits LC Limited undesirable consequences MB Moderate project benefits MC Moderate undesirable consequences LB Limited project benefits SC Significant undesirable project NBC No anticipated project benefits or impacts undesirable consequences

Source: Pedersen Planning Consultants, 2000

Recommended Option and Estimated Project Cost

The planting of additional riparian vegetation (Option 2) along the 600-foot stream segment is recommended for implementation. This wetland restoration project is recommended because the project can significantly enhance riparian vegetation, help stabilize stream banks, and reduce sedimentation in Pala Lagoon for a reasonable cost.

The costs associated with this project would primarily be associated with the collection and planting of 100 native riparian trees. The planting would include a combination of ifi, fau, laufala, and falaga tree cuttings that would be provided by the ASCC Land Grant Program. Some of these cuttings may already be available. The estimated cost for the planting of 100 native riparian trees would be approximately $2,471 (Table 8-6).

TABLE 8-6 PRELIMINARY COST ESTIMATE PLANTING OF RIPARIAN TREES ALONG LOWER SAUINO STREAM

LABOR Personnel Number Hours Hourly Rate ($) Cost ($) ASCC Plant Nursery Technician 1 104 10 1,040 ASCC Field Crew Leader 1 8 8 64 ASCC Field Crew Members 2 8 6 96 All Personnel 4 128 $1,200 MATERIALS Item Quantity Unit Cost ($) Cost ($) Riparian Trees 100 3 300 Garbage Bags 20 boxes 5 100 All Materials $400 EQUIPMENT Shovels 3 22 66 Machetes 3 20 60 Picks 3 15 45 Wheel Barrows 2 50 100 Weed-eaters 2 300 600 All Equipment $871 TOTAL LABOR AND MATERIALS $2,471 Notes: Preliminary estimate assumes use of existing equipment that is owned by the ASG Department of Public Works

Source: Pedersen Planning Consultants, 2000

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-11 Long-Term Monitoring and Site Maintenance Requirements

Long-term resource management activities associated with the enhancement of the 600-foot Sauino Stream segment should include the seasonal monitoring of selected resource characteristics and periodic site maintenance.

Resource Monitoring

The process of resource monitoring will involve completion of the following steps by ASEPA, ASCMP, or other ASG agency staff:

Long term monitoring of the Sauino Stream restoration and enhancement project will require periodic examinations of, at least, the following:

• the presence of stream flow; • potential impedances to stream discharge; • evidence of eroding stream bank areas; • potential failures or damages to gabion baskets or rock walls along the stream bank; • survival of planted, riparian trees; • potential flood damages to commercial and public facility properties; • changes in land uses immediately adjacent to the stream banks; • point-source discharges, e.g., storm water; and, • changes in the type and number of fish and invertebrates near station 1+00.

The types of information needed, monitoring frequency, monitoring locations, and evaluation parameters are summarized in Table 8-7. A field work sheet or checklist, which can be used in the field, is provided in Table 8-8.

Future resource monitoring can be effectively performed through bi-annual site visits to lower Sauino Stream. This approach will enable comparisons during wet (December through March) and dry (April through November) seasons of the year. Additional visits should also take place during and/or following significant stormwater events that may be generated from periods of significant rainfall.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-12 TABLE 8-7 LONG-TERM RESOURCE MONITORING REQUIREMENTS AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN SAUINO STREAM

Resource Information Monitoring Monitoring Monitoring Evaluation Requirement Frequency Method Location(s) Parameters Wetland/Stream Stream Flow 1 x (Dec-March) Visual observation Station 1+00 through Station 6+00 Presence of stream flow or obstructions to stream flow Hydrology 1 x (April-Nov) Stream Channel Stream channel 1 x (Dec-March) Measure manually, using tape measure Sauino Stream: 500 feet upstream of Changes in dimensions of stream channel trapezoid cross sections 1 x (April-Nov) Station 1+00 at 100-foot intervals Stream Modifications Changes to 1 x (Dec-March) Take digital photos, measure manually Sauino Stream: 500 feet upstream of Evidence of bank erosion, changes in flow path, or new stream banks 1 x (April-Nov) using tape measure, record type & size, Station 1+00 manmade structures along stream bank (e.g., rock walls) locate changes on map, incorporate data into GIS Water Quality Changes in land 1 x (Dec-March) Take digital photos, document type and Within 100 feet of Sauino Stream Do new land uses generate non-point surface or subsurface uses 1 x (April-Nov) estimated size, locate changes on map, discharges into the stream channel? incorporate data into GIS Vegetation Survival of new 1 x (Dec-March) Take visual count of new riparian Stream banks between Station 1+00 andNumber of plants that remain vegetation 1 x (April-Nov) trees Station 6+00 Aquatic Fish Type and number 2 x (Dec-March) Collection of driftnet samples of outgoing 10 feet upstream of Station 1+00 Changes in diversity and abundance of fish and and Invertebrates of fish and 2 x (April-Nov) larvae for 3-4 hour evening periods. crustaceans. crustaceans (See report narrative for detail.) Molluscs Type and number 2 x (Dec-March) Mark-recapture technology or quadrant 10 feet upstream of Station 1+00 Changes in diversity and abundance of molluscs. of molluscs 2 x (April-Nov) counts at night. TABLE 8-8 FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN SAUINO STREAM

PAGE 1 of 3 PAGES Date(s) of field monitoring:______Name(s) of observer(s): Agency/Company Represented:

Sauino Stream STREAM AND WETLAND HYDROLOGY (Circle "yes" or "no") 1 Is water flowing in the stream (between Station 1+00 and Station 6+00)? Yes No 2a Are stream flows continuing immediately downstream of Station 1+00? Yes No b If no, what appears to be impeding stream discharge? Describe.

STREAM CHANNEL MODIFICATIONS 3 a Has the stream bank been altered and with what material has the alteration been made? Yes No ___ Basaltic rock wall ___ Concrete wall ___ Rock-filled gabions ___ Other, please describe: b If alteration has occurred, locate on field map. _____ Check, when field map is so marked. 4 a Do existing rock walls, concrete walls or gabions appear to have been damaged from past or recent stormwater events? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 5 a Is there evidence of bank erosion? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 6 a Do you see evidence of a change in the stream flow path? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked

SURVIVAL OF NEW RIPARIAN PLANTS 8 a Count number of surviving new riparian trees b Count number of surviving new fruit trees

CHANGES IN LAND USE 9 a Document type and number of new land uses within 100 feet of Sauino Stream channel. Number of facilities: Briefly describe each new facility: Residential Commercial Industrial Public Facility Community Facility Agricultural b Map location of new land uses on field map. ___ Check, when field map is so marked 10 a Do any existing land uses, within 100 feet of the stream channel, appear to have sustained damage from past or recent stormwater events? Yes No b If so, where? (Locate on field map.) ___ Check, when field map is so marked

NON-POINT DISCHARGES INTO STREAM CHANNEL 11 Type of discharges: Briefly describe type of discharge: Piggery Stormwater Cesspool Industrial Commercial 12 Locate discharge on field map ___ Check, when field map is so marked TABLE 8-8 (Continued) FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN VAIPITO STREAM

PAGE 2 of 3 PAGES

FISH AND INVERTEBRATES 13 Identify the type and number of fish observed via the collection of driftnet samples of outgoing larvae. Family Genus/Specie Number Observed a Fish

b Crustaceans

MOLLUSCS 14 Identify the type and number of molluscs that were observed by mark-recapture technology or quadrant counts. Family Genus/Specie Number Observed TABLE 8-8 (Continued) FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN SAUINO STREAM

Station Sauino Stream

1+ 00 E AB

C D F

2 + 00 E AB

C D F

3 + 00 E AB

C D F

4 + 00 E AB

C D F

5 + 00 E AB

C D F

6 + 00 E AB

C D F Vehicular and pedestrian access to selected monitoring stations is largely dependent upon the cooperation and authorization of local residents and the Nuuuli Village Council. Assuming that residents cooperatively permit periodic access for long-term resource monitoring, field monitoring should begin at the station 1+00 and extend 500 feet upstream (Figure 8-4). Future measurements of changes in the stream channel trapezoid will require the continued use of the same stream cross section stations used for the present study.

Photographs made during field monitoring should be incorporated into the digital photo album developed by PPC in conjunction with the Wetland/Stream Restoration and Enhancement Plan. This will enable a long-term comparison of resource information.

More specific monitoring of stream fauna should be made along Sauino Stream in the vicinity of the station 1+00. Such monitoring should include the collection of driftnet samples of outgoing larvae, at least two times per month, for 3-4 hour evening periods. The driftnets (150- 200 ųm mesh) should be attached to rebar pounded into the stream substrata, or simply suspended from trees or bridges to that the net is at the surface of the water. The samples would subsequently be preserved in ethanol. The type and number of fish and crustaceans should be enumerated using a dissecting microscope. Use of the dissecting microscope will likely require a 2-3 day training class and the necessary equipment for field monitoring personnel.

Site Maintenance

Periodic site maintenance should take place along the 600-foot stream segment approximately four times per year. Household wastes along the 600-foot segment of Sauino Stream are expected to represent the primary focus of long-term site maintenance.

A crew of four persons will be necessary to periodically collect and remove discarded solid waste material from the 600-foot segment of Sauino Stream. Periodic cleanups would occur shortly after significant rainfall and stormwater events. Machetes and weed-eaters will be required to periodically trim vegetation along selected portions of the stream channel.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Sauino Stream, Page 8-17 Chapter Nine LEAFU STREAM

LOCATION

Leafu Stream is generally situated in Leone Village along the southwest coast of the Island of Tutuila (Figure 9-1). The stream is accessible via Route 1, which is situated immediately southwest of Leone Pala (Figure 9-2).

The study area included the downstream segment of Leafu Stream that flows through the inhabited village area. In 1998, Pedersen Planning Consultants investigated this stream segment in the context of potential stormwater management opportunities. In November 1999, PPC focused its field investigations more upon the lower 300 feet of Leafu Stream, as well as unnamed stream parallel and immediately west of Leafu Stream. ASG Land Grant Program and ASEPA representatives believed that some wetland and stream enhancement opportunities were more feasible in this area.

STREAM HYDROLOGY

Sources of Surface Runoff

Leafu Stream and its four branches drain approximately 875 acres of land area upslope of Leone Village. The main stem of Leafu Stream, which extends up to the southwest side of Aoloaufou Village, originates near the 1,135-foot elevation.

General Stream Characteristics

Immediately upstream of Leone Pala, the Leafu Stream drainage becomes very different. In this area, Leafu Stream and an adjoining unnamed stream actually represent three to four separate stream channels that are interspersed with small transitory islands of land area. In November 1999, the variations in the topography and stream hydrology of this area were extremely difficult to identify in light of dense herbaceous vegetation and standing water.

Further upstream within the inhabited village area of Leone, the Leafu Stream channel is considerably more narrow. The stream represents a combination of basaltic rock and earth lined channel. Smaller rock, cobble, sand, grass, muck, and decomposed organic material comprise the bottom of the stream channel.

Cross-sections were documented by PPC in May 1998 at three stream locations. Channel depths ranged between two and nine feet below the top of the stream bank (Table 9-1). The width of the stream segment (between east and west stream banks) ranges between 15 and 150 feet. The greatest stream width was recorded at cross section L6 just upstream from Leone Pala.

Onsite surveys along Leafu Stream in May 1998 and November 1999 discovered limited to moderate amounts of solid waste material within the stream bed. In some cases, the type and/or volume of wastes appeared to impede stream flow.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-1 Figure 9-1 Location Map Leafu Stream

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-2 Figure 9-2 Leone Pala and 300-Foot Leafu Stream Segment Existing Conditions

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-3 TABLE 9-1 MEASUREMENTS FROM SELECTED STREAM CROSS SECTIONS, LEAFU STREAM MAY 1998

Station Channel Width of Channel Other Characteristics Width Channel Depth (from top of Bottom (feet) bank - in feet) (feet) L1 N/A N/A 9 9-year resident reports stream flows remain within stream banks L2 20 10 5 Medium rock along bottom L3 15-20 3 N/A Very grassy bottom L4 27 15 2 Rocky bottom primarily comprised of small rock. Scouring observed underneath concrete bridge L5 N/A N/A N/A Berm adjacent to stream provides some protection to adjacent homes L6 150 Un- Un- Wetland plant indicators within undefined defined defined drainageway L7 N/A N/A N/A Concrete-lined channel adjoining unfinished 2- story home on man-made fill area Source: Pedersen Planning Consultants, 1998

In the vicinity of L2, significant stream bank erosion was observed along the west bank of Leafu Stream in both May, 1998 and November, 1999. Continued bank erosion in this area was also evident by an increase in stream channel width that had expanded from 20 feet in May 1998 to 27 feet in November 1999. A former pedestrian stream crossing, which was used to gain access to homes on the west side of Leafu Stream, had been washed out by higher stream flows and increased bank erosion within an 18-month period.

Stream Modifications

Within the inhabited village area, there is evidence of some stream channel modifications. These modifications generally include the past construction of short reaches of basaltic or concrete walls, or rock-filled gabions. These structures have apparently been constructed to keep higher stormwater flows within the stream banks or to prevent flooding on adjoining residential properties.

Stream Flows

In 1996, the U.S. Geological Survey estimated generally comparable rates of median stream flow for two locations along Leafu Stream (Table 9-2). These estimates were based upon continuous and partial gage measurements of stream flow by the U.S. Geological Survey.

TABLE 9-2 MEDIAN STREAM FLOW ESTIMATES LEAFU STREAM

USGS Gage Gage Location Stream Flow Estimated Station Measurements Median Flow (number) (cfs) 16934000 0.9 mile upstream from stream mouth; 36 2.61 30 feet upstream of reservoir 169335000 1.3 miles NE of Leone; 900 feet continuous Oct,1977-Sept, 2.50 upstream of village intake 1986; 5 between 1987-1990 Source: Wong, 1996.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-4 However, during and following heavier rainfall events, stream flow discharges along Leafu Stream are significantly greater. For example, a maximum discharge of 400 cfs at station 169335000 was recorded by USGS on December 3, 1984.

Stormwater Discharges and Related Flood Potential

Stormwater runoff discharges into the Leone Pala are primarily generated from heavier rainfall events that occur within the Leafu Stream drainage. Computer modeling of the Leafu Stream drainage by Pedersen Planning Consultants suggests potential stormwater flows range between 2,350 cubic feet per second (cfs) for a 10-year storm event and 4,098 cfs for a 100-year storm (Table 9-3).

TABLE 9-3 STORMWATER RUNOFF DISCHARGES INTO LEONE PALA 10,50, AND 100-YEAR STORM EVENTS IN CUBIC FEET PER SECOND (CFS)

Location 10-Year Storm 50-Year Storm 100-Year Storm Leafu Stream Mouth 2,350 3,684 4,098

Source: Pedersen Planning Consultants, 1998

The potential flood plain associated with a 100-year storm event in Leone Village was mapped by the Federal Emergency Management Agency (FEMA) in May 1991. Available flood insurance rate maps prepared by FEMA suggest that residential properties along the east and west banks of Leafu Stream could be flooded from a 100-year storm event. The 100-year flood plain extends up to 400 feet west of Leafu Stream and up to 800 feet east of the main channel.

VEGETATION

November 1999 Survey

Art Whistler of Isle Botanica conducted a botanical survey of the lower, 300-foot segment of Leafu Stream on November 8 and 17, 1999. Mr. Whistler was part of a three-person field survey team organized by Pedersen Planning Consultants that observed wetland vegetation, habitat for aquatic fish and invertebrates, stream hydrology, as well as land uses within and adjacent to the wetland. His observations are summarized in the following paragraphs.

The vegetation along the lower 300-foot Leafu Stream is inland from the more significant wetland areas in Leone Pala that include mangrove swamp near the ocean, swamp forests, disturbed freshwater marshes, and wetland taro patches. In November 1999, the inland area, between Leafu Stream and an unnamed stream parallel to Leafu Stream, was comprised of stream banks and transitory islands in the stream channels that were covered with herbaceous vegetation. The vegetation characterizing this inland wetland area was highly disturbed.

The stream banks of this inland area were largely dominated by wetland plants such as mauutoga (commelina or Commelina diffusa), willow primrose (Ludwigia octovalvis), California grass (Brachiaria mutica), Malay ginger (Costus speciosus), and fue saina (mile-a- minute vine). Also present were lesser amounts of weeds such as balsam pear (Momordica charantia), basket grass (Oplismenus compositus), palulu (Stictocardia tiliifolia), and dissotis (Dissotis rotundifolia), and crop plants such as manioka (cassava). Trees included ulu (breadfruit), coconut, and native beach hibiscus.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-5 The wetlands closer to the mouth of Leafu Stream comprised a combination of disturbed marsh, cultivated marsh, fresh- water swamp forest, as well as smaller coconut and banana plantations. In addition, at least one smaller taro patch was located in standing water that was apparently not within the main stream channel. A substantial amount of Ludwigia hyssopifolia and some fue saina (mile-a-minute vine) was observed on the stream banks.

Taro was also growing in drier soils above the stream banks. In this area, taro plants were surrounded by weeds more typical of disturbed, dry land.

Southeast of a relatively new building housing poultry, there were disturbed wetlands that were probably formerly used for taro production prior to the recent taro blight. The disturbed wetland area was dominated in some places by a dense cover of California grass and mile-a-minute vine, as well as lesser amounts of commelina. In other areas, mile-a-minute vine was present without California grass. Scattered trees included beach hibiscus and ifi (Tahitian chestnut). Other less common herbaceous plants included Luffa cylindrica, Struchium sparganophorum, Acmella uliginosa, selesele (Mariscus javanicus), and willow primrose (Ludwigia octovalvis).

Immediately inland of Leone Pala, there was a swamp forest that consisted of dense thickets of beach hibiscus. It appeared that limited vegetation was able to survive in the wet soil or standing water in the shade of the hibiscus canopy. However, occasional clumps of saato (swamp fern) were observed just upstream of the mangroves in Leone Pala.

Vegetation along portions of the inland Leafu Stream segment appeared to resemble an environment between marsh and swamp. These areas contained low patches of beach hibiscus and scattered coconut trees that were surrounded by selesele (Mariscus javanicus), swamp fern, fuapepe (blue rat’s tail), Ludwigia hyssopifolia, and Struchium sparganophorum.

No substantive forest of ifi (Tahitian chestnut) or marsh areas dominated by native species was observed in the 300-foot stream segment upstream of Leone Pala. Plantations along the west margin of the wetland contained banana and scattered coconut trees growing in wet soil (a marginal wetland area) that typically would be expected to be barren.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-6 Vegetation Trends

The lower Leafu Stream drainage represents a wide flood plain containing narrow stream channels. PPC expected this area to be dominated by lowland forest trees such as mamalava (Planchonella samoense), afa (Neonauclea forsteri), and asi toa (Syzygium inophylloides). Along the edges of the lowland, the presence of some falaga was expected with roots in or next to the water. In later times, some ifi would be anticipated in the same position. However, the weedy herbaceous plants and human disturbance prevent these plants from returning to the site (Whistler, 2000).

The disturbed marsh dominated by California grass, fue saina (mile-a-minute vine), and Ludwigia hyssopifolia will probably remain since few native marsh species are present. For example, neither vao tuaniu (marsh fern) or utuutu (water chestnut) were recorded in the disturbed marsh.

The beach hibiscus swamp, which is a climax type of vegetation, will probably remain the same unless significant changes occur in stream hydrology. Stream banks will likely continue to be dominated by alien weedy species except where residents stabilize stream banks with basaltic rock or concrete walls.

Taro will likely continue to be cultivated in this area. Greater taro production can be expected as blight resistant varieties become more available.

AQUATIC FISH AND INVERTEBRATES

General

On November 5, 1999, Charles Chong of the PPC field survey team made observations of aquatic fish and invertebrates along lower Leafu Stream. His observations are summarized in the following paragraphs.

One upstream and one downstream site were surveyed. The upland site was at the cross section location L2. The downstream site was located about 300 feet upstream of Leone Pala.

Fish

A complete complement of sycidine gobies were present and abundant at the upland site. Kuhlia, Anguilla, and Poecilia spp. were common at this location, but more abundant downstream. Eleotris and Awaous spp. were also observed downstream.

While not observed at the upstream or downstream sites, Tilapia was documented in a branch of Leone Pala. It is likely that these fish are distributed throughout Leone Pala, as well as immediately upstream of Leone Pala.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-7 Invertebrates

In terms of crustaceans, Macrobrachium lar and Paleomon spp. were abundant at both the upstream and downstream sites. Ptychognathus was also common at the upstream site while Macrobrachium australe was common downstream.

Two neritid snails were common upstream, but not recorded at the downstream survey site. Greater silt and sediment at the downstream site may be the reason neritid snails were not observed downstream.

Relative Abundance and Diversity of Fish and Invertebrates

A site specific summary of macrofaunal organisms observed during the survey are summarized in Table 9-4. Genera are listed in order of descending abundance within their taxonomic group.

TABLE 9-4 SUMMARY OF MACROFAUNAL ORGANISMS OBSERVED ALONG LEAFU STREAM

Stream Location Fishes Crustaceans Molluscs Lowland approximately Kuhlia Macrobrachium None 400-500 upstream of Leafu Poecilia (2 spp.) (2 spp.) Stream mouth Anguilla Paleomon Eleotris Awaous Station L2 Kuhlia Macrobrachium Neritina Sicyopterus (2 spp.) Paleomon (2 spp.) Stiphodon (2 spp.) Unidentified Graspid Poecilia (2 spp.) crab Anguilla

Source: Chong, 2000

The relative abundance and diversity of fish and invertebrates along the lower and upper Leafu Stream segments are summarized in Table 9-5. The characterization of relative abundance and diversity reflects a general comparison of the abundance and diversity of fish and invertebrates observed along lower and upper Leafu Stream segments with all 10 sites evaluated for the Wetland/Stream Restoration and Enhancement Plan.

Leafu Stream contained the greater bio-diversity of any of the streams surveyed for the overall study. The abundance and diversity of fish and crustaceans were higher compared to the other 10 sites investigated for the study. The abundance of molluscs was moderate, but their diversity was higher.

TABLE 9-5 RELATIVE ABUNDANCE AND DIVERSITY OF FISH AND INVERTEBRATES LOWER LEAFU STREAM

Fishes Crustaceans Molluscs Abundance High High Moderate Diversity High High High

Source: Pedersen Planning Consultants, 2000

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-8 LAND USES ADJACENT TO LOWER LEAFU STREAM

The lower Leafu Stream segment is situated within a low-density residential area of Leone Village. Within the inhabited village area, approximately 30 single family homes are constructed immediately adjacent to the east and west banks of the stream. Although most homes are set back 100-200 feet back from the stream channel. Portions of the stream bank also used for a few, smaller banana plantations and some decorative landscaping.

The paving of the vehicular trail immediately east of Leafu Stream in 1999 may generate some bank erosion along selected stream bank reaches. During construction of the road improvements, no drainage inlets were installed to direct road drainage into the stream. Consequently, road drainage following normal stormwater events has begun to form natural flow paths to Leafu Stream along the road right-of-way and some stream banks along the east bank of the stream.

RIPARIAN RESTORATION AND ENHANCEMENT OPPORTUNITIES

General

Three opportunities were identified for the restoration and enhancement of lower Leafu Stream. One option is located upstream in the vicinity of L2 segment. The other two options represent riparian enhancement project within the 300-foot stream segment immediately upstream of Leone Pala. The scope of these restoration and enhancement opportunities, and related implementation strategies, are presented in the following paragraphs. The potential benefits and impacts derived from the implementation of the recommended strategies are subsequently evaluated and compared in the following paragraphs.

Opportunities and Strategies

Option 1: Restore Stream Bank in Vicinity of L2

Option 1 would construct rock-filled gabions along an eroded stream bank in the vicinity of station L2 (Figure 9-3). The intended objective of the proposed construction would be to stabilize failing or potentially erosive stream bank areas in order to reduce downstream sedimentation.

In the vicinity of L2, gabions would be installed along selected reaches of the east and west sides of the stream. A total of approximately 100-feet of gabions would be constructed at one more sites in the immediate vicinity of L1. In 1999, PPC estimated that such improvements would cost approximately $20,700.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-9 FIGURE 9-3 OPTION 1: RESTORE STREAM BANKI IN VICINITY OF L1

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-10 Option 2: Construct Basaltic Wall, Stabilize East Stream Bank, and Enhance Riparian Vegetation

In the vicinity of station L6, a trench would be excavated along 300 linear feet of the drainage area. The trench would be located immediately west of existing residences on the east side of the Leafu Stream drainage (Figure 9-4).

A basaltic rock wall would be constructed within the trench using wire gabions approximately 4x3x10-feet in size. Presence of the wall would better define the east stream bank and help direct future stream flows. At the same time, the wall may also help reduce potential flood damage from medium stream flows. However, stream hardening along the east stream bank could also generate an increase in stream flow velocities during stormwater events.

Some basaltic rock treatment would be made on the top and east side of the wall to ensure that the wall would be attractive and complement existing residential and subsistence agricultural development. The wall would also be back-filled with native soil on the east side of the wall to reduce the visual impact of the wire gabions (Figure 9-4).

West of the proposed wall, the east stream bank would be enhanced through the planting of roughly 100 native riparian trees such as ifi (Tahitian chestnut) fau, laufala, and falaga. Such plants would increase the stability of the east stream bank that adjoins residential properties. The propagation of seeds and/or collection of tree cuttings would be made by the ASCC Land Grant Program nursery and planted by Land Grant personnel in cooperation with local landowners.

Option 3: Stabilize East Stream Bank and Enhance Riparian Vegetation

Option 3 would be very similar to Option 2 except that no basaltic wall would be constructed to better define the margin of the east stream bank near L6. Otherwise, the same type and number of native riparian trees would be planted along portions of the east stream bank near L6 (Figure 9-5).

The establishment of ifi (Tahitian chestnut), fau, laufala, and falaga and other native riparian trees along the east stream would primarily help stabilize the east bank that adjoins residential and subsistence agricultural land uses. The root systems associated with these trees contain roots that can effectively help stabilize the soil.

The propagation of seeds and/or collection of tree cuttings would be made by the ASCC Land Grant Program nursery and planted by Land Grant personnel in cooperation with local landowners. However, the ASCC Land Grant Program may elect to encourage adjoining residents to participate in the planting of these trees along the east stream bank.

ASCC Land Grant has considerable experience with encouraging community participation through its Forestry Stewardship Program. Colin Steele, ASCC/AHNR project forester, envisions that the establishment of native riparian trees and the related participation of residents can best be accomplished by providing, at no charge, a total of 30 tree seedlings to each household along the stream. However, the “no charge” arrangement would be conditional to the resident’s agreement to plant the new trees within 30 feet of the stream bank (Steele, 1995). Consequently, some 100 riparian tree plantings would be randomly planted along the east bank, roughly 300-550 feet upstream of the stream mouth.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-11 Figure 9-4 Option 2: Construction of Basaltic Wall in Vicinity of Station L6

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-12 Figure 9-5: Stabilize East Stream Bank and Enhance Riparian Vegetation

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-13 Comparative Benefits and Impacts

PPC’s evaluation of the three alternate restoration and enhancement strategies is summarized in Table 9-6. Options 2 and 3 primarily enhance bank stabilization and riparian vegetation. Both of these options generate a comparable level of overall project benefits. However, Option 3 is recommended to avoid the potential generation of increased stream velocities via the construction of a man-made wall along the east stream bank.

Option 2 provides somewhat greater benefits in the reduction of potential flood damages within the adjoining residential area. However, during stormwater events, increased stream hardening would increase stream velocities in the lower Leafu Stream channel. In addition, the costs associated with the implementation of Option 2 are somewhat greater.

Option 1 also provides enhanced bank stabilization in the vicinity of station L2. Increased bank stabilization will help reduce downstream sedimentation, as well as provide some nominal benefits to adjoining land uses.

TABLE 9-6 COMPARATIVE EVALUATION RIPARIAN RESTORATION AND ENHANCEMENT OPPORTUNITIES LOWER LEAFU STREAM SEGMENT

Notes: Potential project benefits were rated by PPC as follows: SB Significant project benefits LC Limited undesirable consequences MB Moderate project benefits MC Moderate undesirable consequences LB Limited project benefits SC Significant undesirable project NBC No anticipated project benefits or undesirable impacts consequences

Source: Pedersen Planning Consultants, 2000

Recommended Option and Estimated Project Cost

Option 3 is recommended for future stream enhancement. The estimated cost of implementation would be approximately $2,471.

The estimated costs associated with this project would primarily be associated with the propagation and planting of 100 ifi, fau, laufala, and falaga seedlings by the ASCC Land Grant Program for $2,471 (Table 9-7).

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-14 TABLE 9-7 PRELIMINARY COST ESTIMATE PROPAGATION AND PLANTING OF RIPARIAN TREES ALONG LOWER LEAFU STREAM

LABOR Personnel Number Hours Hourly Rate ($) Cost ($) ASCC Plant Nursery Technician 1 104 10 1,040 ASCC Field Crew Leader 1 8 8 64 ASCC Field Crew Members 2 8 6 96 All Personnel 4 128 $1,200 MATERIALS Item Quantity Unit Cost ($) Cost ($) Riparian Trees 100 3 $300 Garbage Bags 20 boxes 5 100 All Materials $400 EQUIPMENT Shovels 3 22 66 Machetes 3 20 60 Picks 3 15 45 Wheel Barrows 2 50 100 Weed-eaters 2 300 600 All Equipment 8771 TOTAL LABOR AND MATERIALS $2,471

Notes: Preliminary estimate assumes use of existing equipment that is owned by the ASG Department of Public Works

Source: Pedersen Planning Consultants, 2000

Long-Term Monitoring and Site Maintenance Requirements

Long-term resource management activities associated with the enhancement of the 300-foot Leafu Stream segment should include the seasonal monitoring of selected resource characteristics and periodic site maintenance.

Resource Monitoring

The process of resource monitoring will involve completion of the following steps by ASEPA, ASCMP, or other ASG agency staff:

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-15 Long term monitoring of the Leafu Stream restoration and enhancement project will require periodic examinations of, at least, the following:

• the presence of stream flow; • potential impedances to stream discharge; • evidence of eroding stream bank areas; • survival of planted, riparian trees; • potential flood damages to commercial and public facility properties; • changes in land uses immediately adjacent to the stream banks; • point-source discharges, e.g., storm water; and, • changes in the type and number of fish and invertebrates approximately 400-500 feet upstream from Leafu Stream mouth.

The types of information needed, monitoring frequency, monitoring locations, and evaluation parameters are summarized in Table 9-8. A field work sheet or checklist, which can be used in the field, is provided in Table 9-9.

Future resource monitoring can be effectively performed through bi-annual site visits to lower Leafu Stream. This approach will enable comparisons during wet (December through March) and dry (April through November) seasons of the year. Additional visits should also take place during and/or following significant stormwater events that may be generated from periods of significant rainfall.

Vehicular and pedestrian access to selected monitoring stations is largely dependent upon the cooperation and authorization of local residents and the Leone Village Council. Assuming that residents cooperatively permit periodic access for long-term resource monitoring, field monitoring should begin at the stream mouth and continue about 300 feet upstream (Figure 9- 4).

PPC has provided digital files for the Wetland and Stream Restoration and Enhancement Plan that provide a departure point for locating future resource monitoring area along lower Leafu Stream.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-16 TABLE 9-8 LONG-TERM RESOURCE MONITORING REQUIREMENTS AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN LEAFU STREAM

Resource Information Monitoring Monitoring Monitoring Evaluation Requirement Frequency Method Location(s) Parameters Wetland/Stream Stream Flow 1 x (Dec-March) Visual observation Leafu Stream mouth to 500 feet upstream Presence of stream flow or obstructions to stream flow Hydrology 1 x (April-Nov) Visual observation Stream Modifications Changes to 1 x (Dec-March) Take digital photos, measure manually Leafu Stream mouth to 300 feet upstream Evidence of bank erosion, changes in flow path, or new stream banks 1 x (April-Nov) using tape measure, record type & size, manmade structures along stream bank (e.g., rock walls) locate changes on map, incorporate data into GIS Vegetation Survival of new 1 x (Dec-March) Take visual count of new riparian trees Along east bank roughly 300-550 feet upstream Number of plants that remain vegetation 1 x (April-Nov) of Leafu Stream mouth Water Quality Changes in land 1 x (Dec-March) Take digital photos, document type and Within 100 feet of Leafu Stream bank Do new land uses generate non-point surface or subsurface uses 1 x (April-Nov) estimated size, locate changes on map, discharges into wetland or stream channels? incorporate data into GIS Aquatic Fish Type and number 2 x (Dec-March) Collection of driftnet samples of outgoing400-500 feet upstream of Leafu Sream mouth Changes in diversity and abundance of fish & crustaceans. and Invertebrates of fish and 2 x (April-Nov) larvae for 3-4 hour evening periods crustaceans (See report narrative for detail.) Molluscs Type and number 2 x (Dec-March) Mark - recapture technology or 400-500 feet upstream of Leafu Stream mouth Changes in diversity and abundance of molluscs. of molluscs 2 x (April-Nov) quadrant counts at night TABLE 9-9 FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN LEAFU STREAM

PAGE 1 OF 2 PAGES Date(s) of field monitoring:______Name(s) of observer(s): Agency/Company Represented:

Leafu Stream STREAM AND WETLAND HYDROLOGY (Circle "yes" or "no".) 1 Is water flowing in the stream? Yes No 2a Are stream flows entering Leone Pala? Yes No b If no, what appears to be impeding stream discharge? Describe.

SURVIVAL OF NEW RIPARIAN PLANTS 7 Count number of surviving new riparian trees

NON-POINT DISCHARGES INTO STREAM CHANNEL OR WETLAND 10 Type of discharges: Briefly describe type of discharge: Piggery Stormwater Cesspool Industrial Commercial 11 Locate discharge on field map. ___ Check, when field map is so marked TABLE 9-9 (Continued) FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN LEAFU STREAM

PAGE 2 OF 2 PAGES

FISH AND INVERTEBRATES 12 Identify the type and number of fish observed via the collection of driftnet samples of outgoing larvae. Family Genus/Specie Number Observed a Fish

b Crustaceans

MOLLUSCS 13 Identify the type and number of molluscs that were observed by mark-recapture technology or quadrant counts. Family Genus/Specie Number Observed More specific monitoring of stream fauna should be made along lower Leafu Stream approximately 400-500 feet upstream of the Leafu Stream mouth. Such monitoring should include the collection of driftnet samples of outgoing larvae, at least two times per month, for 3-4 hour evening periods. The driftnets (150-200 ųm mesh) should be attached to rebar pounded into the stream substrata, or simply suspended from trees or bridges to that the net is at the surface of the water. The samples would subsequently be preserved in ethanol. The type and number of fish and crustaceans should be enumerated using a dissecting microscope. Use of the dissecting microscope will likely require a 2-3 day training class and the necessary equipment.

Molluscs should be monitored by mark-recapture methodology, or quadrant counts at night since most are primarily nocturnal. Some training in these techniques is recommended.

Site Maintenance

Periodic site maintenance should take place along the 300-foot stream segment approximately four times per year. Household and agricultural wastes along the 300-foot segment of Leafu Stream are expected to represent the primary focus of long-term site maintenance.

A crew of three persons will be necessary to periodically collect and remove discarded solid waste material from the 300-foot segment of Leafu Stream. Periodic cleanups would occur shortly after significant rainfall and stormwater events. Machetes and weed-eaters will be required to periodically trim vegetation along selected portions of the stream channel.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Leafu Stream, Page 9-20 Chapter Ten ASILI STREAM

LOCATION

Asili Stream is located along the southwest coast of the Island of Tutuila (Figure 10-1). The stream segment investigated for this study extends from the Asili Stream mouth to about 1,000 feet upstream of the shoreline (Figure 10-2).

STREAM HYDROLOGY

Sources of Surface Runoff

The Asili Stream drainage carries surface runoff from the south and southwest slopes of a central plateau in west Tutuila that is situated west of Aoloaufou. This central plateau is situated at about the 1,200-foot elevation.

Seven tributaries contribute runoff to the main stem of Asili Stream between the 180-foot and 800-foot elevation. Downstream of these confluences, the main stem of the stream continues downslope, through Asili Village, to the adjoining shoreline.

General Stream Characteristics

Stream cross-sections documented by PPC in November 1999 indicate that the width of the stream segment (between east and west stream banks) ranges between 17 and 43 feet (Figure 10-2). The depth of the stream channel (between the top of bank to the bottom of the stream bed) is between 2.0 and 7.5-feet along the east side of the stream. Along the west side of the stream, the depth of the stream channel ranges between 2 and 10 feet below the stream bank.

The stream channel bed is composed of exposed basalt and larger boulders, smaller rock cobble, sand, and decomposed organic material. Rock and solid waste material are found at various points within the streambed, as well as along the banks of the stream. A sandy streambed is evident between the stream mouth and the Route 1 bridge.

In November 1999, general stream channel characteristics exhibited signs of former stream discharges that contained significant stream volume and velocity. Immediately above the village, residents informed PPC representatives that they have observed the flooding of the most upstream residential property along the west side of the stream. A survey of the stream channel upstream of this property by PPC suggests that flooding has probably been generated by larger basaltic boulders that have apparently been carried into the main stem of the stream during more recent stormwater events. A small “island” of land area appeared to have recently formed along the west bank of the stream. The presence of larger boulders upstream may have modified the former path of stream flow. With the change in stream flow path, storm flows gradually bisected a portion of the west stream bank. Consequently, future stormwater flows may soon threaten the most upstream residence in Asili Village.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-1 Figure 10-1 Location Map Asili Stream Drainage

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-2 Figure 10-2 Asili Stream Segment Existing Conditions

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-3 A 75-foot reach of rock-filled gabions was observed along the east side of Asili Stream near station 9+00. Five gabion baskets were also documented in the vicinity of station 6+00 along the east side of the stream. Both sets of gabions were apparently constructed by residents to help prevent flooding from higher stream flows.

Past flooding in the vicinity of station 4+00 was reported by one resident who recalled the flooding of one guest fale along the west bank of the stream (Maugaotega, 1999). Erosion of the stream bank was also evident in this location.

Stream Flows

Historical Stream Flows

Three stream gages have historically been established by the U.S. Geological Survey at various points along Asili Stream (Table 10-1). The data gained from these stream gages provide an insight of historical stream flows along Asili Stream.

Between 1977 and 1986, a continuous-record gage (No. 16931500) was established at the 330- foot elevation. These measurements enabled USGS to calculate an estimated median flow of 1.60 cubic feet per second (cfs).

The same gage was operated as a partial-record site between 1987 and 1990. Extreme flows recorded during this period included a maximum discharge of 653 cfs on October 28, 1960 and a minimum of 0.20 cfs on August 6, 1983.

Another partial record station (No. 16932500) was operated 100 feet upstream from the Route 1 bridge between 1959 and 1990. Data generated from 34 measurements of stream flow were used by USGS to estimate a median stream flow of 2.85 cfs (Wong, 1996).

Various other one to two-day measurements of stream flow were made by USGS at various points along Asili Stream. This data is not presented since more reliable data was obtained from the three other stream gages (Table 10-1).

TABLE 10-1 MEDIAN STREAM FLOW ESTIMATE ASILI STREAM

USGS Gage Location Stream Flow Estimated Median Gage Station Measurements Flow (cfs) (number) 16931500 0.8 mile upstream from stream Continuously recorded 1.60 mouth at the 330-foot between 1977-1986 elevation. 16932000 0.5 mile upstream from the 24 1.85 Asili Stream mouth. 16932500 100 feet upstream of Route 1 34 2.85 bridge. Source: Wong, 1996

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-4 Stormwater Discharges and Related Flood Potential

Pedersen Planning Consultants made a hydrologic analysis of potential stormwater discharges into Asili Bay that could be generated from a range of storm. Through hydrologic modeling, PPC determined that potential stormwater discharges into Asili Bay can range from 620 cubic feet per second (cfs) for a 2-year storm and about 1,606 cfs for a 100-year storm. Consequently, significant stream flows can be carried by Asili Stream for more frequent 2-year events, as well as less frequent 100-year storms.

TABLE 10-2 STORMWATER DISCHARGES FROM ASILI STREAM 2,10,50, AND 100-YEAR STORM EVENTS IN CUBIC FEET PER SECOND (CFS)

2-Year Storm 10-Year Storm 50-Year Storm 100-Year Storm 620 938 1,468 1,606

Source: Pedersen Planning Consultants, 2000

In November 1999, PPC also gathered cross-sectional data along the 1,000-foot Asili Stream segment to assess the capability of this stream segment to accommodate these stormwater events. Cross sections were recorded at 100-foot intervals along this stream segment.

With the application of hydrologic modeling, PPC determined that potential stormwater flows are greater than the capacity of most stream cross-sections (Table 10-3). One important exception is the bridge culverts underneath Route 1 (station 3+00), which can accommodate stormwater flows of about 7,614 cfs. Consequently, the culverts underneath Route 1 can support potential flows from a 100-year storm event.

TABLE 10-3 CROSS-SECTIONAL ANALYSIS ALONG ASILI STREAM SEGMENT

Maximum Stream Flow Slope of Stream Through Cross Section Station (percent) (cfs) 1+00 2.5 416.5 2+00 2.5 261.1 3+00 2.5 7,614.1 4+00 2.5 2,326.7 5+00 2.5 1,139.4 6+00 2.5 542.6 7+00 2.5 516.2 8+00 2.5 382.2 9+00 2.5 246.5 10+00 2.5 1,103.7

Source: Pedersen Planning Consultants, 2000 The potential flood plain associated with a 100-year storm event in Asili was mapped by the Federal Emergency Management Agency (FEMA) in May 1991. Available flood insurance

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-5 rate maps prepared by FEMA suggest that residential properties along the east and west banks of the Asili Stream segment could be flooded from a 100-year storm event. FEMA also indicates that culvert underneath the Route 1 bridge is capable of containing flows from a 100- year storm event.

Surface Water Quality

During its November 1999 survey, PPC representatives informally met with Mr. Tago, a village matai and member of the Fono. Mr. Tago reported that a significant amount of sediment is discharged from Asili Stream during and following storm events. He believes that turbid surface water discharges are due, in part, to erosion occurring in upland areas of the village that are used for the production of various subsistence crops.

From October 1995 through May 1996, ASEPA conducted a water quality monitoring program at selected streams in Asili, Leone and Afono. This program was aimed at gaining a better understanding of the source of sediments that impact surface water quality in the selected streams.

Along each stream, weekly samples were obtained from stream locations that were adjacent to developed lands, a plantation, and undeveloped lands. Water samples were subsequently analyzed to determine concentrations of total suspended solids (TSS), turbidity, total nutrients, and total phosphorus.

Data obtained from this water quality monitoring program did not detect any significant difference in water quality between the three types of stations along Asili Stream. Consequently, it remains unclear whether or not upstream plantations are contributing any significant amounts of eroded soil material into Asili Stream.

VEGETATION

November, 1999 Survey

Art Whistler of Isle Botanica conducted a botanical survey of the Asili Stream segment on November 10, 1999. The walk-through survey was made within the stream banks from station 1+00 and station 10+00 (Figure 10-2). Mr. Whistler was part of a three-person field survey team organized by Pedersen Planning Consultants that observed wetland vegetation, habitat for aquatic fish and invertebrates, stream hydrology, as well as land uses within and adjacent to the wetland. His observations are summarized in the following paragraphs.

The vegetation of Asili Stream was comprised of plants growing along the stream banks. One exception is the small “island” along the west stream bank that is situated immediately upstream of the most upstream home in Asili Village. The “island” was covered with dense herbaceous vegetation dominated by vao lima (T-grass). Less amounts of Malay ginger (Costus speciosus) and taamu (giant taro) were interspersed with banana trees and laupata (Macaranga harveyana). Taamu (giant taro, Alocasia macrorrhiza) The edge of subsistence plantations were adjacent to the stream banks in the vicinity of stations 9+00 and 10+00. This area was dominated by plantation trees and weeds that are not characteristic of wetlands.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-6 Further downstream, the stream channel becomes more narrow and rocky. Native forest trees along the east and west stream banks included afa (Neonauclea forsteri), fuafua (Kleinhovia hospita), fau (beach hibiscus), and maota mamala (Dysoxylum samoense). Wetland trees such as ifi (Tahitian chestnut) and falaga (Barringtonia samoensis), as well as cultivated trees such as ulu (breadfruit) also dominated this area. The ground cover consisted of basket grass, T- grass, and various weeds that are characteristic of upland vegetation.

Lands adjacent to the lower portion of Asili Stream were more disturbed and contained cultivated trees such as vi (Polynesian plum), beach hibiscus, coconut, and breadfruit. Rock walls, concrete walls, and rock-filled gabion baskets reinforced most of the stream banks. Where man-made flood control structures were not present, barren soils and soils covered with weeds were observed. Some landscaped lawns also were also established immediately above the stream banks.

Between the stream mouth and the Route 1 bridge, a more lagoon type of environment was evident. The seaward side of the stream channel contained modified littoral vegetation.

Vegetation Trends

No prior studies of the vegetation of Asili Stream have been conducted. Consequently, no correlation can be made concerning historical vegetative trends.

The Asili Stream segment was probably once dominated by the same species that were observed upslope of the village. This vegetation comprises trees such as afa (Neonauclea forsteri), fuafua (Kleinhovia hospita), fau, and maota mamala (Dysoxylum samoense). Wetland trees such as ifi and falaga are also present upstream of the village.

The upper portion of the Asili Stream segment will probably remain in disturbed vegetation as long as residents continue to harvest and use crops from subsistence plantations. The middle and lower portions of the stream segment are also expected to remain generally the same. However, the amount of vegetation along the stream banks may diminish somewhat if residents continue to build more flood control structures in response to future storm events.

AQUATIC FISH AND INVERTEBRATES

General

On November 10, 1999, Charles Chong of the PPC field survey team made observations of aquatic fish and invertebrates along the 1,000-foot segment of Asili Stream. His observations are summarized in the following paragraphs.

An overstory canopy covered much of the stream channel between the stream mouth and the inhabited residential area along the stream. Upstream of the village, the canopy over the stream was more open.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-7 Stream flows observed during the survey represented a low flow condition of about 1-2 cfs. Surface waters appeared slightly milky upstream of the village.

Immediately upstream of the inhabited village area, periphyton covered rocks within the stream. The periphyton complex, which primarily consisted of Cladophora and Spirogyra, was especially heavy since a stormwater event had occurred only three weeks prior to the survey. The heavier cover was probably due to the increased amount of sunlight reaching the water. However, the increased amount of algae could also reflect nutrient inputs generated from upstream agricultural activities.

Fish

Near the stream mouth, Kuhlia spp. and Mugil were abundant. Four species of gobies were common. Eleotrids and a small anguillid were also observed in this area.

Upstream of the village, gobies were also common. A plentiful population of Kuhlia was also documented.

Invertebrates

Two species of neritid snails were common along the stream segment. However, no Poecilia were recorded.

Macrobrachium lar and Paleomon spp. were abundant upstream of the inhabited village area.

Relative Abundance and Diversity of Fish and Invertebrates

A site specific summary of macrofaunal organisms observed during the survey are summarized in Table 10-4. Genera are listed in order of descending abundance within their taxonomic group.

The relative abundance and diversity of fish and invertebrates along Asili Stream is summarized in Table 10-5. The characterization of relative abundance and diversity reflects a general comparison of the abundance and diversity of fish and invertebrates observed along the Asili Stream segment will all other sites evaluated for the Wetland/Stream Restoration and Enhancement Plan.

Asili Stream contained a moderate diversity and abundance of fish and invertebrates.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-8 TABLE 10-4 SUMMARY OF MACROFAUNAL ORGANISMS OBSERVED ALONG ASILI STREAM

Stream Location Fishes Crustaceans Molluscs Lowland approximately 150- Kuhlia Macrobrachium None feet upstream of Asili Stream Mugil mouth Sicyopterus Eleotris Awaous Stiphodon Stenogobius Eleotris Anguilla Station 10+00 Kuhlia Macrobrachium Neritina (2 spp.) Sicyopterus Paleomon Stiphodon

Source: Chong, 2000

TABLE 10-5 RELATIVE ABUNDANCE AND DIVERSITY OF FISH AND INVERTEBRATES ASILI STREAM

Fishes Crustaceans Molluscs Abundance Medium Medium Medium Diversity Medium Medium Medium

Source: Pedersen Planning Consultants, 2000

LAND USES ADJACENT TO ASILI STREAM

Most of the Asili Stream segment is situated immediately adjacent to residential uses. Seaward of the Route 1 bridge, no residential uses were located adjacent to the stream.

A few piggeries were also located near the banks of the stream. In some cases, wastewater from these piggeries discharged into Asili Stream.

Solid waste discarded from the 12 residences along the stream poses the greatest impact upon stream hydrology and aquatic habitat. However, discarded solid waste material did not appear to prevent the flow of surface runoff along the main stem of the stream.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-9 RIPARIAN RESTORATION AND ENHANCEMENT OPPORTUNITIES

General

Two opportunities were identified for the restoration and enhancement of lower Asili Stream. The scope of these restoration and enhancement opportunities, and related implementation strategies, are presented in the following paragraphs. The potential benefits and impacts derived from the implementation of the recommended strategies are subsequently evaluated and compared in the following paragraphs.

Opportunities and Strategies

Option 1: Clean Asili Stream and Enhance Riparian Vegetation

The initial phase of Option 1 would represent the clean up of solid waste material within the banks of Asili Stream. More specifically, the cleanup would occur between the stream mouth and station 10+00, the first 1,000 feet upstream of the stream mouth (Figure 10-3). This effort will require the collection and disposal of a wide variety of solid waste materials. Manual collection will be sufficient to collect of this material. A larger dump truck may be required to haul larger materials to the Futiga landfill.

Subsequently, The American Samoa Community College, Land Grant Program would initiate the planting of 25 ifi (Tahitian chestnut) and 25 falaga trees along the banks of Asili Stream. Such plantings would be most beneficial along the margins of subsistence plantations that are adjacent to Asili Stream. Both ifi and falaga trees will help stabilize stream banks and help decrease potential downstream sedimentation. It is recommended that tree plantings are made within 25 feet of the east and west stream banks except where plantings interfere with adjoining residential land uses, or are not authorized by residents living adjacent to Asili Stream.

Option 2: Restore Stream Flow Path Upstream of Inhabited Village Area

A change in the path of stream flow immediately upstream of the inhabited village area may generate future flood damages to, at least, one residence along the west bank of Asili Stream. Some corrective action will likely be required upstream of station 10+00 to restore the prior path of stream flow.

The construction of riprap upstream of the last residence in the village is recommended to help restore the former path of stream flow along the west bank of the stream, as well as reduce sedimentation that is being generated from the continuing erosion of the west stream bank. Larger basaltic boulders and smaller rock are readily available within the existing stream bed. Consequently, any construction effort would require a modest expense for the material needed to build the riprap. Labor and heavy equipment from the ASG Department of Public Works would be required to haul selected rock material, from the stream bed to the west bank, and construct the riprap structure.

Figure 10-3 Option 1: Clean Asili Stream and Enhance Riparian Vegetation

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-10

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-11 Comparative Benefits and Impacts

PPC’s evaluation of the three alternate restoration and enhancement strategies is summarized in Table 10-6.

TABLE 10-6 COMPARATIVE EVALUATION RIPARIAN RESTORATION AND ENHANCEMENT OPPORTUNITIES LOWER ASILI STREAM

Option Project Residential Subsistence Fish & Wetland/ Stream Flood Cost Land Uses Agriculture Invertebrate Riparian Bank Hazards & Habitat Vegetation Stability Property Damage 1 LC LB SB NBC SB MB NBC 2 MC LB LB NBC NBC SB LB Notes: Potential project benefits were rated by PPC as follows: SB Significant project benefits LC Limited undesirable consequences MB Moderate project benefits MC Moderate undesirable consequences LB Limited project benefits SC Significant undesirable project impacts NBC No anticipated project benefits or undesirable consequences Source: Pedersen Planning Consultants, 2000

Option 1 provides an initial cleanup of lower Asili Stream. The greater benefits associated with this option include the planting of ifi and falaga trees that will help stabilize stream banks, particularly in adjacent subsistence plantations. Greater stabilization of stream banks would help reduce bank erosion along lower Asili Stream. Project costs would be somewhat less than those required to implement Option 2.

Option 2 would also address significant bank erosion and changes in stream hydrology in the vicinity of station 10+00. This project would provide needed stream stabilization along the west bank of the stream and help restore the flow path of Asili Stream in this area. One residence immediately downstream of this proposed improvement would benefit from potential property damages that may occur if needed stream bank stabilization is not constructed.

Recommended Option and Estimated Project Cost

The cleaning of the 1,000-foot segment of Asili Stream and the planting of additional riparian vegetation (Option 1) is recommended for implementation. This wetland restoration project is recommended because the project can enhance wetland vegetation and stabilize stream banks adjacent to smaller subsistence plantations.

The costs associated with this project would primarily be associated with the initial clearing, removal and disposal of solid waste material from the lower reach of Asili Stream, as well as the subsequent collection and planting of ifi and falaga tree cuttings by the ASCC Land Grant Program.

The estimated cost associated with the initial clearing of the 1,000-foot segment of lower Asili Stream is $3,126 (Table 10-7). The propagation and planting of 50 native riparian trees will cost an estimated $2,2 41 (Table 10-8). Consequently, the total estimated project cost would be $5,367. TABLE 10-7 PRELIMINARY COST ESTIMATE

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-12 CLEAN-UP OF LOWER ASILI STREAM

LABOR Personnel Number Hours Hourly Rate ($) Cost ($) Supervisor 1 24 15 360 Heavy Equipment Operator 1 24 13 312 Laborer 4 24 6 576 All Personnel 6 144 $1,248 MATERIALS Item Quantity Unit Cost ($) Cost ($) Picks 4 15 60 Sledge Hammers 4 25 100 Shovel 4 22 88 Weed-eaters 4 300 1,200 Machetes 4 20 80 Garbage Bags 30 boxes 5 150 Wheel Barrows 4 50 200 All Materials $1,878

TOTAL LABOR AND MATERIALS $3,126

Notes: Preliminary estimate assumes use of existing equipment that is owned by the ASG Department of Public Works

Source: Pedersen Planning Consultants, 2000

TABLE 10-8 PRELIMINARY COST ESTIMATE PROPAGATION AND PLANTING OF NATIVE RIPARIAN TREES LOWER ASILI STREAM

LABOR Personnel Number Hours Hourly Rate ($) Cost ($) ASCC Plant Nursery Technician 1 104 10 1,040 ASCC Field Crew Leader 1 4 8 32 ASCC Field Crew Members 2 4 6 48 All Personnel 4 116 $1,120 MATERIALS Item Quantity Unit Cost ($) Cost ($) Native Riparian Trees 50 3 150 Garbage Bags 20 boxes 5 100 All Materials $250 EQUIPMENT Shovels 3 22 66 Machetes 3 20 60 Picks 3 15 45 Wheel Barrows 2 50 100 Weed-eaters 2 300 600 All Equipment $871

TOTAL LABOR AND MATERIALS $2,241 Notes: Preliminary estimate assumes use of existing equipment that is owned by the ASG Department of Public Works

Source: Pedersen Planning Consultants, 2000

Long-Term Monitoring and Site Maintenance Requirements

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-13 Long-term resource management activities associated with the restoration of the lower Asili Stream should include the seasonal monitoring of selected resource characteristics and periodic site maintenance.

Resource Monitoring

The process of resource monitoring will involve completion of the following steps by ASEPA, ASCMP, or other ASG agency staff:

Long term monitoring of the Asili Stream restoration and enhancement project will require periodic examinations of, at least, the following:

• the presence of stream flow; • potential impedances to stream discharge; • evidence of eroding stream bank areas; • potential failures or damages to gabion baskets or rock walls along the stream bank; • survival of planted, riparian trees; • potential flood damages to commercial and public facility properties; • changes in land uses immediately adjacent to the stream banks; • point-source discharges, e.g., wastewater from piggeries; and, • changes in the type and number of fish and invertebrates approximately 150 feet upstream from Asili Stream mouth.

The types of information needed, monitoring frequency, monitoring locations, and evaluation parameters are summarized in Table 10-9. A field work sheet or checklist, which can be used in the field, is provided in Table 10-10.

Future resource monitoring can be effectively performed through bi-annual site visits to lower Asili Stream. This approach will enable comparisons during wet (December through March) and dry (April through November) seasons of the year. Additional visits should also take place during and/or following significant stormwater events that may be generated from periods of significant rainfall.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-14 TABLE 10-9 LONG-TERM RESOURCE MONITORING REQUIREMENTS AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN ASILI STREAM

Aquatic Fish Type and number 2 x (Dec-March) Collection of driftnet samples of outgoing 150 feet upstream of Station 1+00. Changes in diversity and abundance of fish and and Invertebrates of fish and 2 x (April-Nov) larvae for 3-4 hour evening periods. crustaceans. crustaceans (See report narrative for detail.) Molluscs Type and number 2 x (Dec-March) Mark-recapture technology or quadrant 150 feet upstream of Station 1+00 Changes in diversity and abundance of molluscs. of molluscs 2 x (April-Nov) counts at night. TABLE 10-10 FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN ASILI STREAM PAGE 1 of 3 PAGES Date(s) of field monitoring:______Name(s) of observer(s): Agency/Company Represented:

Asili Stream STREAM AND WETLAND HYDROLOGY (Circle "yes" or "no") 1 Is water flowing in the stream (between Station 1+00 and Station 10+00)? Yes No 2a Are stream flows entering the nearshore waters? Yes No b If no, what appears to be impeding stream discharge? Describe.

STREAM CHANNEL MODIFICATIONS 3 a Has the stream bank been altered and with what material has the alteration been made? Yes No ___ Basaltic rock wall ___ Concrete wall ___ Rock-filled gabions ___ Other, please describe: b If alteration has occurred, locate on field map. _____ Check, when field map is so marked. 4 a Do existing rock walls, concrete walls or gabions appear to have been damaged from past or recent stormwater events? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 5 a Is there evidence of bank erosion? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked 6 a Do you see evidence of a change in the stream flow path? Yes No b If so, where? (locate on field map) _____ Check, when field map is so marked

CHANGES IN LAND USE 9 a Document type and number of new land uses within 100 feet of stream channel. Number of facilities: Briefly describe each new facility: Residential Commercial Industrial Public Facility Community Facility Agricultural b Map location of new land uses on field map. ___ Check, when field map is so marked 10 a Do any existing land uses, within 100 feet of the stream channel, appear to have sustained damage from past or recent stormwater events? Yes No b If so, where? (Locate on field map.) ___ Check, when field map is so marked

NON-POINT DISCHARGES INTO STREAM CHANNEL 11 Type of discharges: Briefly describe type of discharge: Piggery Stormwater Cesspool Industrial Commercial 12 Locate discharge on field map ___ Check, when field map is so marked TABLE 10-10 (Continued) FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN ASILI STREAM

PAGE 2 of 3 PAGES

FISH AND INVERTEBRATES 13 Identify the type and number of fish observed via the collection of driftnet samples of outgoing larvae. Family Genus/Specie Number Observed a Fish

b Crustaceans

MOLLUSCS 14 Identify the type and number of molluscs that were observed by mark-recapture technology or quadrant counts. Family Genus/Specie Number Observed TABLE 10-10 (CONTINUED) FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN ASILI STREAM PAGE 3 of 3 PAGES CHANGES IN STREAM CHANNEL TRAPEZOID 7 For each trapezoid represented below, measure the distances between 1) Points A and B, 2) Points C and D, and 3) Points E and F. Write in the measurement on each trapezoid.

Station Asili Stream Station Asili Stream

1+ 00 E 8+ 00 E ABAB

C D C D FF

2 + 00 E 9+ 00 E ABAB

C D C D FF

3 + 00 E 10+ 00 E ABAB

C D C D FF

4 + 00 E AB

C D F

5 + 00 E AB

C D F

6 + 00 E AB

C D F

7 + 00 E AB

C D F Vehicular and pedestrian access to selected monitoring stations is largely dependent upon the cooperation and authorization of local residents and the Asili Village Council. Assuming that residents cooperatively permit periodic access for long-term resource monitoring, field monitoring should begin at station 1+00 and continue upstream to station 10+00 (Figure 10-3).

PPC has provided digital files for the Wetland and Stream Restoration and Enhancement Plan that provide a departure point for locating future resource monitoring area along lower Asili Stream.

Measurements should also be made of the stream trapezoid to more specifically quantify changes in stream hydrology. In essence, these measurements would be made at the same cross-section stations (stations 1+00 through 10+00) used for this study (Figure 10-2 and Table 10-10):

More specific monitoring of stream fauna should be made approximately 150 feet upstream of the Asili Stream mouth. Such monitoring should include the collection of driftnet samples of outgoing larvae, at least two times per month, for 3-4 hour evening periods. The driftnets (150- 200 ųm mesh) should be attached to rebar pounded into the stream substrata, or simply suspended from trees or bridges to that the net is at the surface of the water. The samples would subsequently be preserved in ethanol. The type and number of fish and crustaceans should be enumerated using a dissecting microscope. Use of the dissecting microscope will likely require a 2-3 day training class and the necessary equipment.

Molluscs should be monitored by mark-recapture methodology, or quadrant counts at night since most are primarily nocturnal. Some training in these techniques is recommended.

Site Maintenance

The initial cleanup of lower Asili Stream will represent an important first step toward long- term stream enhancement. However, the initial cleanup is of limited benefit if it is not connected to the implementation of a long-term maintenance strategy.

Periodic site maintenance should take place along lower Asili Stream approximately four times per year. Household wastes along the 1,000 feet of Asili Stream are expected to represent the primary focus of long-term site maintenance.

A crew of 8 persons will be necessary to periodically collect and remove discarded solid waste material from the 1,000-foot segment of Asili Stream. Periodic cleanups would occur shortly after significant rainfall and stormwater events. Machetes and weed-eaters will be required to periodically trim vegetation along selected portions of the stream channel.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Asili Stream, Page 10-19 Chapter Eleven FUSI WETLAND

LOCATION

Fusi Village is located along the southwest coast of the Island of Tau (Figure 11-1). The Fusi wetland is located immediately upland of Tau Harbor and the primary shoreline vehicular trail along the west coast of Tau (Figure 11-2). Past studies suggest that this site comprises approximately 1.45 acres of wetland (Biosystems Analysis, 1993).

WETLAND HYDROLOGY

Sources of Surface Runoff to the Fusi Wetland

Field observations by Pedersen Planning Consultants in November 1999 discovered that there are no streams that discharge to the wetland. Available topographic maps also confirm that no stream or surface water bodies are connected hydrologically to the Fusi wetland.

However, limited surface water (less than one cfs) was observed entering the north side of the wetland via sheet flow drainage from the steeper slopes east of the wetland. In addition, conditions within one or two ponded water areas within the wetland suggested the possible hydrologic connection to a fresh-water spring.

The Fusi wetland is situated within a few hundred feet of the shoreline and nearshore waters. However, no hydrologic outlet was detected during the survey. One west Tau resident also confirmed that no outlet was present (Sega, 1999).

Stormwater Discharges and Related Flood Potential

There is no significant flood potential in the vicinity of the Fusi wetland. The entire Island of Tau was mapped by the Federal Emergency Management Agency (FEMA) in May 1991 to identify potential 100-year flood plain areas. Available flood insurance rate maps indicate that the entire island is zone “x”. This designation signifies areas that are located outside of the 500-year flood plain. Consequently, potential stormwater discharges within the Fusi wetland and adjoining residential area are not anticipated.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-1 Figure 11-1 Location Map Fusi Wetland

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-2 Figure 11-2 Fusi Wetland Existing Conditions

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-3 WETLAND VEGETATION

November 1999 Survey

Art Whistler of Isle Botanica conducted a botanical survey of the Fusi wetland on November 9, 1999. Mr. Whistler was part of a three-person field survey team organized by Pedersen Planning Consultants that observed wetland vegetation, habitat for aquatic fish and invertebrates, stream hydrology, as well as land uses within and adjacent to the wetland. His observations are summarized in the following paragraphs.

The north and west boundaries of the wetland are covered with disturbed vegetation and dominated by alien weeds. The south side of the wetland represents secondary forest/plantation that is associated with an occupied house site.

The underlying soils of the wetland contain a significant volume and wide variety of solid waste material. Much of the material was apparently hauled to this site in the aftermath of Hurricane Val in December 1991.

Fresh-Water Swamp

Most of the site was covered with a thicket of fau (beach hibiscus). The dominance of this specie and saturated soils indicate that this wetland should be classified as a fresh-water swamp. Beach hibiscus was the only mature tree found over most of the wetland. However, saplings of lowland forest trees such as maota mamala (Dysoxylum samoense), afa (Neonauclea forsteri), nonu (Indian mulberry), and oa (Bischofia javanica) were also present. The perimeter of the wetland was dominated by disturbed areas and secondary scrub.

The surface of the swamp was relatively devoid of vegetation. The most common species was saato (swamp fern), which probably covered less than five percent of the ground. Other ground cover species included marsh fern (Cyclosorus interruptus) and umbrella sedge (Cyperus alternifolius), as well as many other species observed only once or twice. The most common epiphyte was the fern lau magamaga (Phymatosorus grossus) and lesser amounts of laugapapa (bird’s nest fern).

The adder’s-tongue fern (Ophioglossum reticulatum), which was listed as a rare plant of concern in a recent U.S. Fish and Wildlife Service survey, was found in the fresh-water swamp on several low, moss-covered mounds or rock outcroppings. This species is known in American Samoa only from several collections in the higher elevations of Laufuti Stream on the south side of Tau, as well as from a single collection on Tutuila around 1860.

Disturbed Marsh

The southern part of the wetland is a disturbed marsh. Immediately adjacent to the beach hibiscus thicket is a disturbed marsh that is dominated by fue saina (mile-a-minute vine), willow primrose (Ludwigia octovalvis), as well as lesser amounts of pasio vao (love-in-a-mist) and palulu (Stictocardia tiliifolia). Fue saina and willow primrose are characteristic of wetlands; the latter two weed species are not.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-4 South of this narrow zone and north of the plantation area behind the occupied house, there was a small taro plantation growing on an artificial island delineated by rock embankments. The most common weed among the taro plants was aatasi (Polynesian cress), a plant of considerable importance in traditional Samoan medicine. However, no tamole vai was found in this area.

Vegetation Trends

In 1993, Biosystems Analysis, Inc. recorded beach hibiscus as the dominant plant within the wetland. Beach hibiscus is a swamp species rather than a marsh species; swamps are typically dominated by trees while marshes are dominated by herbs. Six years later, beach hibiscus had taken over most of the wetland in November 1999. Increased shade within the wetland eliminated the typically shade-tolerant marsh species. Only a small amount of swamp fern and even less marsh fern was present in the wetland. No water chestnut was documented.

In November 1999, no falaga (Barringtonia samoensis) or ifi (Tahitian chestnut), which are trees characteristic of wetlands on the Island of Tutuila, were recorded by the PPC survey team. PPC believes that the Fusi wetland margin may have once dominated by fau and falaga. After the arrival of humans on Tau, ifi may also have been present. These large-seed species would not easily disperse to the site without human intervention.

The wettest areas of the wetland are not conducive to the growth of swamp forest as herbs dominate. Consequently, the wetland interior is a marsh rather than a swamp. Marsh species would typically include marsh species such as utuutu (water chestnut) and vao tuaniu (marsh fern).

This wetland was probably once under cultivation. Surface runoff and/or a spring furnished water needed for past taro cultivation. When cultivation discontinued, the wetland became a disturbed marsh. Whistler observed a disturbed marsh condition in 1976; willow primrose was documented within the site at that time.

In the absence of human intervention, it is expected that beach hibiscus swamp forest will remain dominant for a long time. The only possible competition might come from the saplings, e.g., afa. However, only afa is often associated with wetlands. Consequently, a few scattered lowland forest trees may gain a precarious foothold in places with a slightly higher elevation, or on rock outcrops.

AQUATIC FISH AND INVERTEBRATES

General

On November 9, 1999, Charles Chong of the PPC field survey team made observations of the Fusi wetland. His observations are summarized in the following paragraphs.

No flowing water was observed within the Fusi wetland. There was standing water in several pools under heavy foliage. A thick layer of allochthonous material had collected on top of a significant volume of solid wastes below these pools. Because of the heavy canopy and solid waste material below the pools, visibility was limited. However, no macrofaunal organisms were observed during the survey.

Onsite observations indicate that water within the pools was percolating into the substrata and possibly seeping into the nearshore waters of nearby Tau Harbor. A noticeable fresh-water lens within the harbor was observed via snorkeling within the harbor waters.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-5 The lack of stream flow entering the Fusi wetland, as well as no hydrologic outlet, to the nearshore waters prevents the habitation of aquatic fish and invertebrates within the wetland. Aquatic species could only be humanly introduced in the absence of a hydrologic connection to an upland stream or outlet to the nearshore waters.

Relative Abundance and Diversity of Fish and Invertebrates

The relative abundance and diversity of fish and invertebrates observed within the Fusi wetland are summarized in Table 11-1. The characterization of relative abundance and diversity reflects the observation of no fishes, crustaceans, or molluscs. Consequently, the abundance and diversity of fish and invertebrates at the Fusi wetland are clearly less than those observed at all 10 sites evaluated for the Wetland/Stream Restoration and Enhancement Plan.

TABLE 11-1 RELATIVE ABUNDANCE AND DIVERSITY OF FISH AND INVERTEBRATES IN FUSI WETLAND

Fishes Crustaceans Molluscs Abundance None None None Diversity None None None

Source: Pedersen Planning Consultants, 2000

LAND USES IN THE VICINITY OF FUSI WETLAND

As mentioned earlier, the Fusi wetland has been used for the disposal of various types of solid waste material. Much of the wetland apparently contains residential and commercial building materials that were hauled to the wetland in the aftermath of Hurricane Val in 1991. Several homes are situated northwest of the wetland; one additional residence is located on the southeast side.

Solid waste in Fusi wetland

Tau Harbor is located immediately west of the wetland. Several small fishing boats are regularly moored within the harbor.

Fishing boats in Tau Harbor

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-6 WETLAND RESTORATION AND ENHANCEMENT STRATEGIES

General

There are two potential opportunities for the restoration and enhancement of the Fusi wetland. The scope of these restoration and enhancement opportunities and related implementation strategies are presented in the following paragraphs.

Alternate Opportunities and Strategies

Option 1: Remove Solid Waste Material and Plant Wetland Marsh Vegetation

Biosystems Analysis, Inc. suggested in 1993 that the best opportunity for wetland restoration in the Manua Islands was restoration of the Fusi wetland. The initial requirement for the restoration of the former coastal marsh would be the excavation of solid waste material via the primary use of bulldozers, front-end loaders, and trucks (Figure 11-3). Required heavy equipment can probably be obtained from Tau-based, operating divisions of ASPA and/or the ASG Department of Public Works. Secondarily, some smaller materials would be retrieved manually. Subsequently, excavated material would be hauled by truck to the public solid waste landfill situated northeast of Tau High School.

Bulldozers and front-end loaders would subsequently be used to re-grade the site to the contours that were generally identified on 1990 topographic maps for the Fusi area and remove remaining portions of the beach hibiscus thicket. ASCC Land Grant personnel would be used to plant some 50 utuutu (water chestnut), 25 vao tuaniu (marsh fern), 25 selesele (Rhynchospora corymbosa), and 25 saato (swamp fern).

Option 2: Remove Solid Waste Material and Establish Taro Production

Similar to Option 1, the initial action associated with the restoration of the former coastal marsh would be the excavation of solid waste material via the primary use of bulldozers, front-end loaders, and trucks. Required heavy equipment can probably be obtained from Tau-based, operating divisions of ASPA and/or the ASG Department of Public Works. Secondarily, some smaller materials would be retrieved manually. Subsequently, excavated material would be hauled by truck to the public solid waste landfill situated northeast of Tau High School.

Existing vegetation within the wetland would also be cleared to enable use of the wetland for future taro production. Water required from taro production would be derived from rainfall, as well as limited surface water flows from the steeper slopes east of the wetland.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-7 Figure 11-3 Option 1: Remove Solid Waste Material and Plant Wetland Marsh Vegetation

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-8 The portions of the wetland selected for taro production would initially require the excavation of fill material to a minimum soil depth of about one to two feet. In terms of soil preparation, the production of talo toto i le vai (wetland taro) will require manual and/or mechanical tilling of the soil and the possible application of some limited nutrients to the soil.

Taro cuttings from disease-free propagating material would be used to establish the taro. The cuttings are part of a taro plant stem about 12 to 18 inches long that is attached to a 2 to 3-inch section of the corm. Such cuttings would ideally be obtained from the Samoa Ministry of Agriculture in Apia or the ASG Department of Agriculture. Before planting, selected taro cuttings should be carefully inspected, washed with potable water, soaked in a 10 percent bleach solution for 30 seconds, and stored in a dry, cool, and well-ventilated area for 3 to 5 days before planting.

Comparative Benefits and Impacts

PPC’s evaluation of the two alternate restoration and enhancement strategies is summarized in Table 11-2. Both options generate a comparable overall level of project benefits. However, slightly greater benefits are afforded by Option 1 (Figure 11-3).

Option 1 desirably removes solid waste material from the wetland and likely restores the wetland to a coastal marsh through the planting of selected wetland plants. The implementation of Option 2 also would remove solid waste material as well as wetland plants to permit some subsistence agricultural use.

Despite their apparent project benefits, both options are moderately expensive to implement if light of the extensive requirements associated with the removal and hauling of solid waste material. It also likely that both options may not be well received by local residents. One resident suggested to PPC in November 1999 that Fusi residents would likely appreciate the removal of solid waste material. However, once this material would be removed, village residents would likely prefer to use the land for general residential land uses.

TABLE 11-2 COMPARATIVE EVALUATION WETLAND RESTORATION AND ENHANCEMENT OPPORTUNITIES FUSI WETLAND

Source: Pedersen Planning Consultants, 2000

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-9 Recommended Option and Estimated Project Cost

Should reasonable village support exist for Option 1, this project is recommended for project implementation. While costly, this wetland enhancement project is attractive because the project could likely achieve restoration of a disturbed marsh to a coastal marsh. Removal and hauling of solid wastes, as well as the planting of coastal marsh plants is estimated to cost roughly $10,224 (Table 11-3 and Table 11-4).

TABLE 11-3 PRELIMINARY COST ESTIMATE COLLECTION, REMOVAL AND HAULING OF SOLID WASTE MATERIAL FUSI WETLAND LABOR Personnel Number Hours Hourly Rate ($) Cost ($) Supervisor 1 80 15 1,200 Heavy Equipment Operator 3 60 13 2,340 Laborer 4 80 6 1,920 All Personnel 8 580 $5,460 MATERIALS Item Quantity Unit Cost ($) Cost ($) Picks 4 15 60 Sledge Hammers 4 25 100 Shovel 4 22 88 Weed-eaters 4 300 1,200 Machetes 4 20 80 Garbage Bags 50 boxes 5 250 Wheel Barrows 4 50 200 All Materials $1,978 TOTAL LABOR AND MATERIALS $7,438 Notes: Preliminary estimate assumes use of existing equipment owned by the ASG Department of Public Works. Source: Pedersen Planning Consultants, 2000

TABLE 11-4 PRELIMINARY COST ESTIMATE PROPAGATION AND PLANTING OF COASTAL MARSH VEGETATION FUSI WETLAND LABOR Personnel Number Hours Hourly Rate ($) Cost ($) ASCC Plant Nursery Technician 1 104 10 1,040 ASCC Field Crew Leader 1 20 8 160 ASCC Field Crew Members 2 20 6 240 All Personnel 4 164 $1,440 MATERIALS Item Quantity Unit Cost ($) Cost ($) Coastal Marsh Plants 125 3 375 Garbage Bags 20 boxes 5 100 All Materials $475 EQUIPMENT Shovels 3 22 66 Machetes 3 20 60 Picks 3 15 45 Wheel Barrows 2 50 100 Weed-eaters 2 300 600 All Equipment $871 TOTAL LABOR AND MATERIALS $2,786 Notes: Preliminary estimate assumes use of existing equipment owned by the ASG Department of Public Works. Source: Pedersen Planning Consultants, 2000

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-10 Long-Term Monitoring and Site Maintenance Requirements

Long-term resource management activities associated with the enhancement and restoration of the Fusi wetland should include the seasonal monitoring of selected resource characteristics and periodic site maintenance.

Resource Monitoring

The process of resource monitoring will involve completion of the following steps by ASEPA, ASCMP, or other ASG agency staff:

Long term monitoring of the Fusi wetland restoration and enhancement project will require periodic examinations of, at least, the following:

• the presence of surface or groundwater flow; • survival of planted, wetland vegetation; • changes in land uses immediately adjacent to the wetland; and, • point-source discharges, e.g., wastewater from piggeries.

The types of information needed, monitoring frequency, monitoring locations, and evaluation parameters are summarized in Table 11-5. A field work sheet or checklist, which can be used in the field, is provided in Table 11-6.

Future resource monitoring can be effectively performed through bi-annual site visits to the Fusi wetland. This approach will enable comparisons during wet (December through March) and dry (April through November) seasons of the year. Additional visits should also take place during and/or following significant stormwater events that may be generated from periods of significant rainfall.

Vehicular and pedestrian access to the wetland is largely dependent upon the cooperation and authorization of local residents in Fusi. If access is granted, the entire wetland should be monitored via walk-through surveys.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-11 TABLE 11-6 FIELD MONITORING WORKSHEET AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN FUSI WETLAND

Date(s) of field monitoring:______Name(s) of observer(s): Agency/Company Represented:

Fusi Wetland (Circle "yes" or "no".) STREAM AND WETLAND HYDROLOGY 1 Is there evidence of a fresh water spring discharge? Yes No 2 Are surface flows entering the wetland? Yes No

SURVIVAL OF NEW WETLAND PLANTS 3 Count number of surviving new coastal marsh plants.

CHANGES IN LAND USE 4 a Document type and number of new land uses within 100 feet of the wetland perimeter. Number of facilities: Briefly describe each new facility: Residential Commercial Industrial Public Facility Community Facility Agricultural b Map location of new land uses on field map. ___ Check, when field map is so marked 5 a Do any existing land uses, within 100 feet of the wetland perimeter, appear to have sustained damage from past or recent stormwater events? Yes No b If so, where? (Locate on field map.) ___ Check, when field map is so marked

NON-POINT DISCHARGES INTO WETLAND 6 Type of discharges: Briefly describe type of discharge: Piggery Stormwater Cesspool Industrial Commercial 7 Locate discharge on field map ___ Check, when field map is so marked TABLE 11-5 LONG-TERM RESOURCE MONITORING REQUIREMENTS AMERICAN SAMOA WETLAND RESTORATION AND ENHANCEMENT PLAN FUSI WETLAND

Resource Information Monitoring Monitoring Monitoring Evaluation Requirement Frequency Method Location(s) Parameters Wetland/Stream Surface or 1 x (Dec-March) Visual observation Along north and east margin of wetland Presence of flow from spring or surface runoff from upland Hydrology groundwater flow 1 x (April-Nov) slopes Water Quality Changes in land 1 x (Dec-March) Take digital photos, document type and Within 100 feet of wetland perimeter Do new land uses generate non-point surface or subsurface uses 1 x (April-Nov) estimated size, locate changes on field discharges into the wetland? map Vegetation Survival of new 1 x (Dec-March) Take visual count of new coastal marsh Within entire wetland Number of plants that remain coastal marsh 1 x (April-Nov) plants plants Any future monitoring stations or sites that may be established should be used consistently unless unanticipated events, new land uses, or access issues prevent continued use. When necessary, changes in the location of monitoring stations should be documented and spatially located within the American Samoa GIS. PPC has provided digital files for the Wetland and Stream Restoration and Enhancement Plan that provide a departure point for locating future resource monitoring stations within the wetland.

Site Maintenance

Periodic site maintenance should take place within the Fusi wetland two times per year. It is recommended that maintenance take place immediately following the resource monitoring activities to reduce the amount of air travel to the site. However, local residents could likely be hired to accomplish long-term site maintenance to eliminate the need to transport a maintenance crew from Tutuila.

The collection of solid wastes within the wetland is expected to represent the primary focus of long-term site maintenance. A crew of two persons will be necessary to walk through the Fusi wetland for periodic, long-term maintenance. The use of garbage bags and machetes will be needed to support these activities.

American Samoa Wetlands/Streams Restoration and Enhancement Plan February 2001, Fusi Wetland, Page 11-14 Chapter Twelve FUTURE PROGRAM MANAGEMENT

RECOMMENDED PROGRAM PARTICIPANTS

Implementation of the recommended restoration and enhancement projects will require a diverse set of experience and expertise that is available from, at least, the following governmental agencies in American Samoa:

• American Samoa Environmental Protection Agency • American Samoa Coastal Management Program • American Samoa Community College, Land Grant Program • ASG Department of Marine and Wildlife Resources • American Samoa Power Authority • ASG Department of Public Works • U.S. Natural Resources Conservation Service

It is essential that restoration and enhancement projects be carried out on a cooperative basis by these agencies. A representative of either the American Samoa Environmental Protection Agency or the American Samoa Coastal Management Program should assume the role of overall program manager to organize and administer the overall cooperative program.

Representatives of the other participating agencies could meet periodically, e.g., monthly, with the overall program manager to prioritize restoration and enhancement projects, coordinate and schedule specific project tasks, keep abreast of project status, share information gained from field observations and other related information. In order to reduce some duplication, an existing inter-agency committee organized by ASEPA for future watershed management could serve as this group.

Another option is to use the proposed Watershed Resource Management Board that was recommended in the recent Watershed Protection Plan. Stream and wetland restoration and enhancement projects could clearly represent a portion of the proposed mandate of the Water Resource Management Board. The Board could again be comprised of the members on the existing inter-agency committee for watershed management.

INDIVIDUAL PROJECT ASSIGNMENTS

Each restoration and enhancement project will require one or more individuals to manage and carry out specific restoration and enhancement projects at each of the selected wetlands and streams. Project managers for each project would logically report to the overall program manager. Recommended village coordinators and stream team personnel would report to project managers. In some cases, e.g., Alao wetland, only a project manager would be required given the recommended scope of enhancement projects.

A general description of the duties and responsibilities associated with each of the individual project assignments is presented in the following paragraphs.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Future Program Management, Page 12-1

Project Manager

Representatives of any of the participating agencies would logically serve as individual project managers. For example, if the primary thrust of a project is to enhance aquatic fish and invertebrate habitat, the selection of a project manager from the ASG Department of Marine and Wildlife Resources would be ideal if qualified personnel were available to assume this responsibility.

The project manager would direct the activities of a village project coordinator and recommended Stream Team, coordinate with traditional village leaders and residents living adjacent to the selected stream or wetland, and coordinate with representatives of other ASG agencies.

Village Coordinator

The approval and commitment of local villages to each enhancement and restoration project is essential. The commitment of a local village coordinators to this responsibility will, in large part, depend upon their understanding of resource relationships and potential stream enhancement benefits.

A village coordinator, e.g., pulenuu or matai, would be assigned to each project to:

• organize and mobilize Stream Team cleanup and long-term stream maintenance activities; • observe and document stream and wetland conditions during and following future storm events; • monitor the conditions of other resources, e.g., vegetation, fish and invertebrates; and, • keep the overall project manager abreast of work progress.

Stream and Wetland Teams

American Samoans are well known for their excellent ability to work collectively in groups. The use of small Stream or Wetland Teams can capitalize upon these capabilities.

Where recommended, stream and wetland Teams of various sizes should be organized and employed by ASEPA or ASCMP to initially clean up selected stream channels and wetlands, as well as provide long-term monthly maintenance. These teams should only be established where stream or wetland cleanups are necessary to initiate other restoration and enhancement projects. It is envisioned that their work would, in some cases, be supplemented by heavy equipment support from the American Samoa Power Authority or the ASG Department of Public Works.

Stream and wetland teams would ideally be comprised of members of the village aumaga, or other village residents. Each team member could be supplied with attractive T-shirts, caps, pants, and/or boots that identify that they are part of a specific stream team, e.g., Papa Stream Team. The use of some type of informal uniform should be considered to bring about some camaraderie among these employees. Uniforms for these personnel would also help advertise the project to local residents as these employees work in local streams and wetlands.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Future Program Management, Page 12-2 SELECTED AGENCY ASSIGNMENTS

Aside from the coordination of overall program coordination, it is recommended that some agencies provide specific technical assistance in the field. The field activities envisioned for the ASCC Land Grant Program and ASG Department of Marine and Wildlife Resources are presented in the following paragraphs.

ASCC Land Grant Program

It is envisioned that the ASCC Land Grant Program would provide riparian tree seedlings to households along selected streams or adjacent to selected wetlands. Land Grant has experience with this task through its ongoing Forestry Stewardship Program.

Land Grant representatives would also provide local residents with some technical assistance concerning desired planting methods, as well as perform all in-stream plantings. However, local residents can perform plantings along higher stream banks and riparian areas effectively.

American Samoa Department of Marine and Wildlife Resources

One or more biologists from the American Samoa Department of Marine and Wildlife Resources could be used to perform an initial monitoring program of fish and invertebrates. Long-term monitoring of aquatic fish and invertebrates may be able to be accomplished by the ASDMWR biologists, village coordinators, other village resident, if some initial basic training is provided by an ASDMWR representative, or a consultant.

POTENTIAL PARTICIPATION FROM OTHER COMMUNITY ORGANIZATIONS

Despite the potential availability of federal funds for this project, ASEPA and ASDOC should encourage the participation of one or more community organizations, e.g., Rotary Club, that regularly support community improvement projects. General solicitations should also be made to private businesses and possible individual donors in the community. Community organizations and local businesses may desire to provide some financial support and/or materials needed by the project.

These potential contributions are important because they can express a greater community commitment to the stream enhancement project. They may also stir greater interest among village residents. If and when contributions are obtained, ASEPA and ASDOC should clearly honor their commitment to the project in the form of some public recognition of their participation.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, Future Program Management, Page 12-3 REFERENCES

Biosystems Analysis, Inc. January, 1992. A Comprehensive Wetlands Management Plan for the Islands of Tutuila and Aunu’u, American Samoa. American Samoa Economic Development Planning Office and Coastal Management Program. Pago Pago, American Samoa.

Biosystems Analysis, Inc. September, 1993. A Comprehensive Wetlands Management Plan for the Islands of Manu’a, American Samoa. American Samoa Economic Development Planning Office and Coastal Management Program. Pago Pago, American Samoa.

Bledsoe, Brian P.; Wuenscher, James E.; and Sutter, Lori A. 1998. Using Geographic Information Systems to Identify and Prioritize Potential Wetland Restoration Sites in Coastal North Carolina. North Carolina Division of Coastal Management.

California Resources Agency. 1998. California Wetlands Information System: Explanation of Tracking Table Categories.

DuPoldt, Jr., Carl A.; Terrell, Charles R.; Franzen, Robert W.; and Wengrzynek, Robert J., Jr. 1991. Nutrient and Sediment Control System, Environmental Quality Technical Note No. N4. U.S. Department of Agriculture, Soil Conservation Service.

Engbring, John, and Ramsey, Fred L. 1989. A 1986 Survey of the Forest Birds of American Samoa. U. S. Department of Interior, Fish and Wildlife Service and American Samoa Office of Marine and Wildlife Resources. Pago Pago, American Samoa.

Louisiana Department of Natural Resources, Coastal Restoration Division. 1998. Vegetation Planting Program. Louisiana Department of Natural Resources.

Madrigal, Larry G. Field Guide of Shallow Water Marine Invertebrates of American Samoa. American Samoa Government Department of Education, Division of Curriculum and Instruction. Pago Pago, American Samoa.

Pedersen Planning Consultants. 2000. American Samoa Watershed Protection Plan, Volumes 1-4. American Samoa Government Environmental Protection Agency and Coastal Management Program. Pago Pago, American Samoa.

Pedersen Planning Consultants, 2000. Tualauta County Land Use Plan – Draft. American Samoa Department of Commerce. Pago Pago, American Samoa.

Stemmermann, Lani. 1981. A Guide to Pacific Wetland Plants. U. S. Army Corps of Engineers, Honolulu District. Honolulu, Hawaii.

The World Conservation Union. Wetlands and Coastal Zones. IUCN Regional Office for Mesoamerica.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, References-1

U. S. Army Corps of Engineers. July, 1981. American Samoa Stream Inventory, Island of Tutuila, American Samoa Water Resources Study. U. S. Army Corps of Engineers, Honolulu District. Honolulu, Hawaii.

U.S. Federal Interagency Stream Restoration Working Group. 1998. Stream Corridor Restoration Principles, Processes, and Practices. National Technical Information Service.

U.S. National Resources Conservation Service, Hawaii State Technical Committee. 1998. Interim Hawaii Procedure for Determinations of Wetland Minimal Effect.

Wass, Richard. November, 1998. Personal Communication. Manager, Hakalau Wildlife Refuge, Island of Hawaii. U.S. Fish and Wildlife Service. Hilo, Hawaii.

Wetland Science Institute. 1998. Wetland National Practice Standards: Wetland Restoration, Wetland Enhancement, Wetland Creation, Constructed Wetland, and Shallow Water Management for Wildlife. U.S. Natural Resources Conservation Service.

Whistler, Dr. W. Arthur. 1996. Samoan Herbal Medicine (‘O La’au ma Vai Fofo o Samoa). Isle Botanica. Honolulu, Hawaii.

Whistler, Dr. W. Arthur. Wayside Plants of the Islands. (A Guide to the Lowland Flora of the Pacific Islands including Hawaii, Samoa, Tonga, Tahiti, Fiji, Guam, Belau). Isle Botanica. Honolulu, Hawaii.

American Samoa Wetland/Stream Restoration and Enhancement Plan February 2001, References-2

APPENDIX A

SUMMARY OF PLANTS OBSERVED BY PEDERSEN PLANNING CONSULTANTS

NOVEMBER 1999

APPENDIX A PLANTS OBSERVED BY PEDERSEN PLANNING CONSULTANTS NOVEMBER 1999 Species Family English Samoan Name Wetland Name Status Acmella uliginosa Asteraceae -- -- NL Acrostichum aureum* Pteridaceae swamp fern -- OBL Alocasia macrorrhiza@ Araceae giant taro ta’amu FAC Alternanthera sessilis Amaranthaceae sessile joyweed -- FAC Antidesma sphaerocarpum* Euphorbiaceae -- -- NL Asplenium nidus* Aspleniaceae bird’s-nest fern laugapapa (Epi.) Axonopus compressus Poaceae carpet grass -- FAC Bambusa vulgaris Poaceae bamboo ‘ofe palagi NL Barringtonia samoensis* Barringtoniaceae -- falaga FACW Bidens alba Asteraceae beggar’s-tick -- NL Bischofia javanica* Euphorbiaceae -- ‘o’a NL Blechum pyramidatum Acanthaceae -- -- FAC Brachiaria mutica Poaceae California grass -- FACW Bruguiera gymnorrhiza* Rhizophoraceae oriental mangrove togo tane FAC Calophyllum inophyllum* Clusiaceae Alexandrian laurel fetau NL Cananga odorata@ Annonaceae ilangilang moso’oi NL Canna indica Cannaceae Indian shot fanamanu FACU Chamaesyce hypericifolia Euphorbiaceae graceful spurge -- FACU Ceiba pentandra Bombacaceae kapok vavae NL Clerodendrum chinense Verbenaceae Honolulu rose losa Honolulu FAC Cocos nucifera* Arecaceae coconut niu FACU Costus speciosus Zingiberaceae Malay ginger -- NL Coix lacryma-jobi@ Poaceae Job’s tears sanasana FACW Colocasia esculenta@ Araceae taro talo OBL Commelina diffusa@ Commelinaceae commelina mau’utoga FAC Cyclosorus interruptus* Thelypteridaceae marsh fern vao tuaniu OBL Cyperus alternifolius Cyperaceae umbrella sedge -- FACW Davallia epiphylla* Davalliaceae -- laugasese (Epi.) Davallia solida* Davalliaceae leather fern laugasese (Epi.) Desmodium triflorum Fabaceae beggarweed -- FACU Digitaria setigera* Poaceae -- -- FAC Diospyros samoensis* Ebenaceae Samoan ebony ‘au’auli NL Dissotis rotundifolia Melastomaceae dissotis -- NL Dysoxylum samoense* Meliaceae -- maota mamala NL Eleocharis dulcis* Cyperaceae water chestnut ‘utu’utu OBL Eriochloa procera Poaceae tropical cupgrass -- FAC Erythrina fusca* Fabaceae -- lalapa?, gatae OBL Erythrina subumbrans Fabaceae Dadap gatae palagi OBL Erythrina variegata* Fabaceae coral tree gatae NL Ficus benghalensis Moraceae Indian banyan* pulu NL Ficus tinctoria* Moraceae dyer’s fig mati FAC Fimbristylis autumnalis Cyperaceae -- -- NL Fimbristylis cymosa* Cyperaceae -- -- FAC+ Flueggea flexuosa Euphorbiaceae -- poumuli NL Geniostoma rupestre* Loganiaceae -- lau mafatifati NL Hernandia nymphaeifolia* Hernandiaceae Chinese lantern tree pu’a NL

Species Family English Samoan Wetland Name Name Status Hibiscus abelmoschus@ Malvaceae -- -- NL Hibiscus manihot Malvaceae tree spinach pele NL Hibiscus tiliaceus* Malvaceae beach hibiscus fau FACW Hoya australis* Asclepiadaceae wax flower lau mafiafia (Epi.) Inocarpus fagifer@ Fabaceae Tahitian chestnut ifi FACU Ipomoea pes-caprae* Convolvulaceae beach morning-glory -- FAC Kyllinga brevifolia@ Cyperaceae -- -- FAC Kyllinga nemoralis Cyperaceae -- -- FAC Kleinhovia hospita* Sterculiaceae -- fu’afu’a NL Leucaena leucocephala Fabaceae wild tamarind -- NL Ludwigia hyssopifolia Onagraceae -- -- FACW Ludwigia octovalvis Onagraceae willow primrose -- OBL Luffa cyclindrica* Cucurbitaceae -- -- NL Macaranga harveyana* Euphorbiaceae -- lau pata NL Mangifera indica Anacardiaceae mango mago FACU Manihot esculenta Euphorbiaceae cassava manioka NL Mariscus javanicus* Cyperaceae -- selesele FACW Merremia peltata* Convolvulaceae -- fue lautetele NL Merremia umbellate Convolvulaceae -- -- NL Mikania micrantha Asteraceae mile-a-minute vine fue saina NL Momordica charantia Cucurbitaceae balsam pear -- FAC Morinda citrifolia@ Rubiaceae Indian mulberry nonu NL Musa Xparadisica@ Musaceae banana fa’I FACU Neonauclea forsteri* Rubiaceae -- afa FACU Nephrolepis hirsutula* Nephrolepidaceae sword fern vao tuaniu NL Operculina turpethum* Convolvulaceae -- -- NL Ophioglossum reticulatum* Ophioglossaceae adder’s tongue fern -- NL Oplismenus compositus@ Poaceae basket grass sefa? FAC Pandanus tectorius* Pandanaceae screwpine laufala FACU Paspalum conjugatum Poaceae T-grass vao lima FAC+ Paspalum vaginatum Poaceae salt grass -- FACW Passiflora foetida Passifloraceae love-in-a-mist pasio vao FACU Pennisetum purpureum Poaceae elephant grass -- FACU Phymatosorus scolopendria* Polypodiaceae -- lau magamaga (Epi.) Pyrrosia lanceolata* Polypodiaceae -- lau tasi (Epi.) Pycreus polystachyos Cyperaceae -- -- FAC Rhizophora mangle* Rhizophoraceae red mangrove togo fafine OBL Rhynchospora corymbosa* Cyperaceae -- selesele OBL Senna alata Fabaceae candelabra plant la’au fai lafa FACU Sorghum sudanense Poaceae -- -- NL Spondias dulcis@ Anacardiaceae Polynesiam plum vi NL Stachytarpheta urticifolia Verbenaceae blue rat’s-tail fuapepe FAC Stictocardia tiliifolia Convolvulaceae -- palulu FACU Struchium sparganophorum Asteraceae -- -- FACW Thespesia populnea* Malvaceae Pacific rosewood milo FAC Vigna marina* Fabaceae beach pea fue sina FACU Wedelia trilobata Asteraceae -- -- FACU (epi.)=epiphyte. FACU-facultative upland plant. FAC=facultative plant. FACW-facultative wetland plant. NL=not listed. OBL-obligate wetland plant. Native species are indicated by an asterisk (*). Polynesian introductions are indicated by a @.

APPENDIX B

SUMMARY OF AQUATIC MACROFAUNAL ORGANISMS OBSERVED BY PEDERSEN PLANNING CONSULTANTS

NOVEMBER 1999

APPENDIX C

SUMMARY OF AQUATIC MACROFAUNAL ORGANISMS OBSERVED BY U. S. ARMY CORPS OF ENGINEERS, U.S. FISH AND WILDLIFE SERVICE, AND B. P. BISHOP MUSEUM AT SELECTED SITES

JULY 1981