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Soils Study Report

Swan Lake Hydroelectric Project (FERC Project No. 2911) Revised Final April 2013

Ketchikan, Alaska

Prepared by: Tetra Tech

Bothell, Washington and McMillen, LLC

Boise, Idaho

Soils Study Report Southeast Alaska Power Agency

Swan Lake Hydroelectric Project April 2013 FERC Project No. 2911 Page i Version: Revised Final

TABLE OF CONTENTS

1. Introduction and Scope of the Study ............................................................................... 1

1.1. Project Description .................................................................................................................... 1

1.2. Purpose ...................................................................................................................................... 1

1.3. Changes Made to the Study Plan in Response to Comments or Permit Conditions ................. 3

1.4. Compliance with Permit Terms and Conditions ........................................................................ 3

2. Procedures ..................................................................................................................... 3

2.1. Analysis Area ............................................................................................................................. 3

2.2. Soil Data ..................................................................................................................................... 3

2.3. Pre-field Contact with Forest Service Resource Managers ....................................................... 4

2.4. Field Investigation ..................................................................................................................... 4

3. Existing Conditions ......................................................................................................... 4

3.1. Environmental Setting ............................................................................................................... 4

3.2. Soils within the Analysis Area .................................................................................................... 5

3.3. Steep Slopes and Mass Movement ........................................................................................... 8

3.4. Shoreline Erosion ..................................................................................................................... 10

4. Project Effects .............................................................................................................. 12

4.1. Identified Issues and Concerns ................................................................................................ 12

4.2. Soil Removed from Productivity by Inundation or Erosion ..................................................... 12

5. Management Requirements and Mitigation Measures .................................................. 13

6. References ................................................................................................................... 13

TABLES

Table 1. Soils within the Analysis area ......................................................................................................... 6 Table 2. Resource Concerns and Measurement Indicators ....................................................................... 12


Swan Lake Hydroelectric Project April 2013 FERC Project No. 2911 Page ii Version: Revised Final

FIGURES

Figure 1. Project Vicinity .............................................................................................................................. 2 Figure 2. Soils in the Vicinity of Swan Lake .................................................................................................. 7 Figure 3. MMI Class 4 Soils and Observed Erosion and Mass Wasting along the Swan Lake Shoreline .. 11

PHOTOS

Photo 1. Bedrock exposure on steep slopes above Swan Lake ................................................................... 8 Photo 2. Steep slopes above Swan Lake ...................................................................................................... 8 Photo 3. Mass wasting feature .................................................................................................................... 9 Photo 4. Mass wasting feature .................................................................................................................... 9 Photo 5. Exposed bedrock shoreline with shallow soils at low lake level (December 2012) .................... 12

ATTACHMENTS

Attachment 1. Response to Agency Comments Received


Swan Lake Hydroelectric Project April 2013 FERC Project No. 2911 Page iii Version: Revised Final

ACRONYMS AND ABBREVIATIONS

CFR Code of Federal Regulations

FERC Federal Energy Regulatory Commission

ft feet

FSM Forest Service Manual

GIS geographic information system

GPS global positioning system

ICD Initial Consultation Document

MMI Mass Movement Index

mi miles

NEPA National Environmental Policy Act

NWI National Wetlands Inventory

Project Swan Lake Hydroelectric Project

SEAPA Southeast Alaska Power Agency

SMU Soil Management Units

USDA United States Department of Agriculture

USFS United States Department of Agriculture, Forest Service


Swan Lake Hydroelectric Project April 2013 FERC Project No. 2911 Page 1 Version: Revised Final

1. INTRODUCTION AND SCOPE OF THE STUDY

1.1. Project Description The Southeast Alaska Power Agency (SEAPA) is the licensee for the Swan Lake Project, Federal Energy Regulatory (FERC) No. 2911 (Project), on the northeast side of Carroll Inlet in Southeast Alaska. SEAPA is currently evaluating the engineering feasibility and value of increasing the storage capacity of the Swan Lake through an increase in the dam height. Around the lake, the FERC boundary follows the 350-foot elevation contour on the Project drawings. SEAPA is planning a 15-foot raise in full pool elevation; dam crest elevation would increase from an elevation of 344 feet to 350 feet to accommodate a new Probable Maximum Flood (PMF) of 347 feet. The normal maximum surface area of the lake would increase from 330 feet to 345 feet. As a result of the proposed action, the maximum operating pool of the reservoir would change from 330 feet mean sea level (MSL) to 345 feet MSL, thereby increasing the active storage capacity of Swan Lake from 81,704 acre-feet to 102,467 acre-feet (an increase of approximately 25 percent).

It is estimated that there are about 14 miles of shoreline around the lake, much of which is moderately to extremely steep (Figure 1). The Project is located in Sections 11, 12, 13, 14, 15, 20, 21, 22, 23, and 27, Township 29 North, Range 91 East, Copper River Meridian. A portion of the proposed lake expansion includes National Forest System (NFS) lands, in the area of Lost Creek, a tributary that enters the existing lake on the northeast side. In this tributary, the 350-foot contour extends 0.8 mile upstream, past the property boundary of the Tongass National Forest (TNF).

The Project’s FERC license sets the Project’s boundary around the lake at the 350-foot elevation contour. As currently proposed, the increased lake will be entirely contained within the existing boundary; but it’s possible that a revision of this boundary may be necessary to allow for operation and maintenance of the Project and to accommodate other Project purposes such as recreation, shoreline control, or protection of environmental resources. Any proposed changes to the facilities, the operation of the lake, and potential changes to the Project boundary will require amending the Project’s FERC license, a process that includes evaluating the potential impacts to environmental resources from the proposed action.

This report documents potential effects to soils as a result of the project. Tasks associated with this study included contacting the Forest Service soil resource staff regarding project-specific concerns, reviewing readily available aerial imagery, conducting a site visit, preparing this report, preparing a specialist report, and determining potential effects and recommending measures to reduce or eliminate adverse impacts on soil resources.

1.2. Purpose This report presents baseline soil information between the existing full pool elevation and the proposed additional inundation of approximately 15 feet of upland habitat (i.e., between the 330-foot and 350-foot elevation; however, some terrestrial resources investigated areas below the dam and aquatic habitat was characterized up to Lost Lake. Soil information sources included the Ketchikan Area soil survey for the Tongass National Forest Area, aerial or satellite imagery, and contact with Forest Service soil resource managers. Field observations occurred in September and December of 2012 where soil conditions were observed from the shoreline and typical mass wasting features within the analysis area were recorded.



Figure 1. Project Vicinity



1.2.1. Changes to Draft Study Reports and Development of NEPA Documents

The 2012 field efforts focused primarily on the area above the dam within the proposed inundation zone around Swan Lake and its major tributaries. In review of the results of these studies on February 27, 2013, it was agreed that a series of NEPA-supporting Resource Reports would address the majority of the comments received on the various study reports (see Attachment 1). The Resource Reports will comprehensively describe all field work and analysis conducted in support of the proposed action at an appropriate scale for each resource, and breakout the potential impacts by land ownership as appropriate. In the February 27 meeting with agencies, it was acknowledged that the remaining field work needs were limited after the 2012 effort, but additional analysis and desktop work will be done to complement the existing data in 2013. Once the results from the Resource Reports and draft Biological Assessments/Biological Evaluations (BA/BE) have been reviewed, these will be discussed with participants in a coordinated forum and appropriate mitigation measures per resource area will be discussed. These will be included as part of the License Amendment in the form of a Draft Environmental Assessment.

Attachment 1 of this report provides a response to general and resource-specific agency comments on the draft Study Report. This Revised Final Study Report incorporates the comments as appropriate. Where changes were not made, they are noted and will be addressed in greater detail in a future Resource Report.

1.3. Changes Made to the Study Plan in Response to Comments or Permit Conditions

No changes were made to the study plan in response to comments or permit conditions.

1.4. Compliance with Permit Terms and Conditions There are no permits required for field observation of soil condition.

2. PROCEDURES

2.1. Analysis Area The analysis area for direct and indirect effects to soils includes the “activity area” (FSM 2554). For this project, the “activity area” is between the current spillway crest elevation of 330 feet and the proposed new dam crest elevation of 350 feet (3 feet of freeboard above the PMF of 347 feet). It is estimated that there are about 14 miles of Swan Lake shoreline at the 350-foot elevation contour, including portions of Lost Creek, Track Creek, Mint Creek, and Fry Creek. The analysis area for soils is estimated to be 140.3 acres (including approximately 2 acres mapped as water).

2.2. Soil Data The primary source for soil data is the Ketchikan Area soil survey for the Tongass National Forest Area.



2.3. Pre-field Contact with Forest Service Resource Managers Forest Service soil resource managers were contacted in August 2012. Darin Silkworth, Soil Scientist, noted there were not any significant concerns for soil erosion, though the general concern associated with a higher water level is that wave action could undercut the slope and result in mass wasting (Silkworth 2012, personal communication).

2.4. Field Investigation The entire perimeter of the lake was observed from a skiff. This occurred in September and again in December 2012 when lake levels were low. The mouth of Lost Creek was accessed via boat, then evaluated on foot up to and beyond the proposed new lake elevation. This work was done in conjunction with aquatic surveys. Representative incidents of shoreline or near shoreline mass wasting were photographed and positions were recorded by GPS.

3. EXISTING CONDITIONS

This section describes the existing condition of soils within the analysis area surrounding Swan Lake. Information is drawn from the Ketchikan Area soil survey and site-specific field observations.

3.1. Environmental Setting The Tongass National Forest, including Revillagigedo Island, is dominated by temperate rainforest. The maritime climate is characterized by cool, wet summers and mild winters with significant precipitation as snow and rainfall. In Ketchikan, approximately 23 miles southwest of the analysis area, typical summer temperatures average 60 – 65° F, while winter temperatures average 39 – 44° F. The year-round average temperature is 51.6° F. Annual precipitation as rainfall averages 117 inches, with the least precipitation (16 percent) occurring from May through July. The wettest month is October with an average of more than 22 inches accumulation. Snowfall accumulation averages 37 inches per year, with the most snow accumulating in January (35 percent) (Western Regional Climate Center 2012). The analysis area lies about 300 to 350 feet higher in elevation than Ketchikan.

Conifer forests dominate the area due to well-drained soils on steep slopes. High precipitation promoting vegetation growth coupled with the cool year-round temperatures suppressing decomposition rates, promote the buildup of an organic layer (duff) on the surface of the mineral soils. This develops an “organic mat” that protects the surface from erosion. Soils with minimal organic mat (<2 inches) are easily disturbed and can lead to excessive erosion of the mineral soil depending on landscape position, such as steep slopes.

Southeast Alaska is geologically composed of linear belts of tectonic assemblages that lay sub-parallel to, and have been accreted to, the continental margin. This coastal group of mountainous islands lies west of the mainland coast range. This area has been subjected to isostatic and tectonic uplift, as well as glacial and other climatic weathering processes (Forest Service 1996). The analysis area lies within the Behn Canal Complex ecological subsection (Norwacki et al. 2001). Swan Lake is one of many long, linear lakes within deep, narrow valleys created as the glacial ice sheet deeply scoured less resistant sedimentary and volcanic rocks while surrounding plutonic rock was more resistant to scour (Norwacki et al. 2001). The steep valley walls and high gradient contained streams transport colluvium and



alluvium to the valley floor. Landslides often initiate along the contact between shallow soils and the steep underlying bedrock (Norwacki et al. 2001).

Bedrock in the project area is made up of the Taku terrane and includes “metamorphosed marine shales and muddy sandstones, metamorphosed andesites, basalts, and rhyolite lavas, along with small amounts of limestone, marble, and conglomerate” (Connor and O’Haire 1988:10). Approximately the western two thirds of Swan Lake are surrounded by Cretacisous to Permian sedimentary and volcanic rocks and deformed equivalents of these rocks due to metamorphasism. Common rock types in higher grade strata include phyllite, schist, and gneiss (Gehrels and Berg 1992). Slopes along the southeast shore of Swan Lake are intrusive bodies of Late Cretaceous age which includes granodiorite, tonalite and subordinate quartz monzonite to quartz diorite and diorite. Unnamed lacustrine, alluvial, and colluvial deposits are deposited in Luck Creek and in Luck Lake near the mouth of Luck Creek (Gehrels and Berg 1992) along with frequent exposures of underlying bedrock.

3.2. Soils within the Analysis Area Soil Management Units (SMUs) within the analysis area are presented in Table 1 and Figure 2. Nearly two thirds (64 percent) of soils within the analysis area are colluvium derived from bedrock or series or complexes that are dominantly comprised of colluvium. About one third (35 percent) of the soils within the analysis area are alluvium. These alluvial deposits are located within the Lost Creek and Mint Creek valley bottoms and also mapped near the lake outlet. Of the 140 acres soil analysis area, about 26 acres would occur on lands not previously conveyed (lands outside of the Project’s boundaries at the 350-foot elevation contour); these primarily consist of SMU 10 (26 acres), and less than 0.25 acre each of SMUs 74D and 75F. SMU 10 is alluvium within the Lost Creek valley bottom.

Colluvium is composed of rock and soil material accumulated at the base of slopes by mass wasting. Colluvium has angular edges and is poorly sorted (varying in size). Colluvium observed along the shoreline generally ranged from very coarse gravels up to boulders.

Alluvium is unconsolidated materials deposited by rivers, frequently found on floodplains and deltas. Alluvium consists of fine materials than colluvium, including silt, sand, clay, gravel and organic matter.



Table 1. Soils within the Analysis area

SMU Name Parent Material

Slope Class (%)

MMI Class (1-4)

Depth to Bedrock (inches) Acres

10 1/ Tonowek and Tuxekan soils

Alluvium 0-15 1 >60 49

1D Vixen fine sandy loam

Colluvium derived from schist and/ or residuum derived from schist 35-60 2 40-60 12

1E Vixen fine sandy loam


1F Vixen fine sandy loam


25 Kaikli-Kina association

Organic material over residuum; Organic material 0-40 1 20-40; 8

35F St. Nicholas-Tolstoi complex

Colluvium derived from schist and/ or residuum derived from schist; Colluvium derived from sandstone and/or residuum weathered from sandstone

75-100 4 8-32; 12-28 9

43EFX Shakan-McGilvery association

Colluvium derived from sedimentary rock; Organic material over residuum weathered from graywacke

60-150 4 15-35; 7-24 6

528E Tolstoi-McGilvery complex

Colluvium derived from sandstone and/or residuum weathered from sandstone; Organic material over residuum weathered from graywacke

60-75 3 12-28; 7-24 10

528F Tolstoi-McGilvery complex

Colluvium derived from sandstone and/or residuum weathered from sandstone; Organic material over residuum weathered from graywacke

75-100 3 12-28; 7-24 1

53F Tolstoi silt loam

Colluvium derived from sandstone and/or residuum weathered from sandstone 75-100 3 12-28 <1

74D 1/ Kupreanof slit loam

Colluvium and/or glaciofluvial deposits 35-60 2 >60 14

74E Kupreanof slit loam


74F Kupreanof slit loam


75E Kupreanof-McGilvery complex

Colluvium and/or glaciofluvial deposits; Organic material over residuum weathered from graywacke

60-75 2 >60; 7-24 2

75F 1/ Kupreanof-McGilvery complex

Colluvium and/or glaciofluvial deposits; Organic material over residuum weathered from graywacke

75-100 3 3

W Freshwater --GIS discrepancy -- -- -- 2 1/ Soils located on NFS lands within 350-foot elevation along Lost Creek



Figure 2. Soils in the Vicinity of Swan Lake



3.3. Steep Slopes and Mass Movement Most slopes surrounding the lake are steep to very steep, including cliffs. These steep slopes were formed by differential scour from the glacial ice sheet. Landslides often initiate along the contact between shallow soils and the steep underlying bedrock (Norwacki et al. 2001).

Photos 1 and 2 show typical slopes surrounding the lake.

Photo 1. Bedrock exposure on steep slopes above Swan Lake

Photo 2. Steep slopes above Swan Lake

Many slopes in Southeast Alaska are prone to landslides due to the steep gradient, shallow soils, and coarse texture (Swanston 1969). The majority of landslides in timbered areas is natural and occurs under varying slope gradients, different soil composition, and soil-water content (Swanston 1969). Numerous mass wasting features were observed along the shoreline during field reconnaissance. Photos 3 and 4 show typical mass wasting features occurring near the existing shoreline.



Photo 3. Mass wasting feature

Photo 4. Mass wasting feature

Mass movement index (MMI) classes are used to group SMUs that have similar properties relative to the stability of natural slopes. Slope gradient is the primary site factor determining the stability of slopes; however, soil type and soil drainage class may also play a role in specific locations. There are four categories of soils, MMI 1 through MMI 4, with MMI 4 being the least stable.

SMUs in the low hazard class (MMI 1) have the least probability of landslides and can be safely managed without a high risk of failures. Best Management Practices (BMPs) are applied on these soils and help to minimize disturbance to these soil types. About 57 acres (41 percent) of the analysis area contains MMI 1 soils.



SMUs in the moderate hazard class (MMI 2) are generally stable in an undisturbed condition; however, any natural disturbance or management practice that adversely changes the complex soil strength relationship can result in slope failures. This class generally includes most well drained soils on slopes ranging from 35 to 60 percent, as well as soils on slopes 35 to 60 percent that are poorly drained. These areas rarely have visible indications of instability (Forest Service 2001). MMI classes in the project area are shown in Table 1. About 32 acres (23 percent) of the analysis area contains MMI2 soils.

SMUs in the high hazard class (MMI 3) have the potential for landslide activity but have a lower probability of failure than MMI 4 soils. These soils are mostly well drained and have slope gradients that are generally greater than 60 percent, but may include some soils on slopes greater than 50 percent that are poorly drained. These areas can show visible indications of instability and past failures, similar to the very high-class soils (Forest Service 2001). The risk of management induced slope failure is high in these areas, but they are generally not precluded from normal forest harvest and roading activities (Forest Service 2008). MMI classes in the project area are shown in Table 1. About 34 acres (24 percent) of the analysis area contains MMI3 soils.

SMUs in the very high hazard class (MMI 4) are the least stable and have the greatest probability of slope failure. MMI 4 slope gradients are generally greater than 75 percent, but include some poorly and very poorly drained soils on 60 percent slopes. These areas may have visible indications of instability and past failures such as slide scarps, tension cracks, jack-straw trees, and/or mixed pedogenic horizons. Nearly all naturally occurring landslides are found on very high-class soils (Forest Service 2001). MMI classes in the project area are shown in Table 1. About 15 acres (11 percent) of the analysis area contains MMI4 soils.

Figure 3 shows the MMI class surrounding the analysis area, along with observed incidents of shoreline erosion and mass wasting. All slides observed at the shoreline were shallow due to the steep slopes on shallow soils underlain by bedrock.

3.4. Shoreline Erosion Region 10 standards and guidelines define erosion as the detachment and transport of individual soils particles or aggregates of particles by ice, wind, water, or gravity. Soils are protected from surface erosion by an organic surface horizon and roots of vegetation. Mineral soils are susceptible to erosion when exposed. Soils with thinner organic mats are easily disturbed than soils with thicker organic mats. The rate of erosion depends primarily on the amount and intensity of rainfall, vegetative ground cover, erodibility of the soil, slope length, and steepness of slope. Natural disturbances and management practices that expose mineral soils increase the erosion rate.

Along the existing shoreline, erosion occurs as a result of frequent inundation, erosive wave action, and variable lake levels exposing unvegetated soil to erosion by rain drops, runoff and wind. Photo 5 shows typical shoreline erosion.



Figure 3. MMI Class 4 Soils and Observed Erosion and Mass Wasting along the Swan Lake Shoreline



Photo 5. Exposed bedrock shoreline with shallow soils at low lake level (December 2012)

4. PROJECT EFFECTS

4.1. Identified Issues and Concerns The identified issues and concerns relevant to soils were developed based on internal review. The primary concern surrounding soils is soil productivity. The environmental components and indicators used to describe potential effects are summarized in Table 2.

Table 2. Resource Concerns and Measurement Indicators

Issue/Concern Environmental Component Measure or Indicator Loss of soil productivity from removal as a result of the project.

Soil conversion from vegetated uplands and wetlands to submerged soils by inundation. Soils exposed to wave action and variable lake level will erode.

Acres of soil inundated on NFS land.

4.2. Soil Removed from Productivity by Inundation or Erosion The project will result in an irreversible loss of approximately 138 acres of soil productivity. An irreversible commitment of resources applies primarily to the loss of non-renewable resources (e.g., minerals or cultural resources) and resources that are renewable only over a long period of time (e.g., soil productivity). All of the soils within the analysis area (Table 1) would be subjected to frequent inundation, erosive wave action, and variable lake levels exposing unvegetated soil to erosion by rain drops, runoff, and wind. This would be similar to the existing conditions along much of the lake



shoreline, although to a larger extent due to the expansion. About 26 acres of soils on NFS lands (lands outside of the Project’s boundaries at the 350-foot elevation contour) would be subject to inundation, including SMU 10, SMU 74D, and SMU 75F. SMU 10 is alluvium within the Lost Creek valley bottom.

Mass wasting events would continue to occur on the steep slopes with shallow bedrock surrounding much of the lake. Increasing the lake level may slightly increase the incidence of mass wasting near the shoreline as slope toes are undercut from shoreline erosion due to a slightly larger amount of shoreline. This would only occur near the shoreline and would be similar to existing conditions. Natural landslides would continue throughout the watershed.

5. MANAGEMENT REQUIREMENTS AND MITIGATION MEASURES

No management requirements or mitigation measures are identified for shoreline erosion.

During project development, implement measures consistent with the National Best Management Practices for Water Quality Management on National Forest System Lands (Forest Service 2012) to avoid, minimize, or mitigate adverse effects to soil, water quality, and riparian resources.

Trees on NFS lands are anticipated to remain standing. Should any trees require removal (stumps left intact) within the activity area (i.e., inundation zone between 330 and 350 feet), the removal would follow applicable Forest Plan Standards and Guidelines as well as Forest Service or State BMPs. This would include conducting a timber cruise and working closely with the Alaska Department of Natural Resources and the Forest Service in the development of timber settlement agreement prior to removal.

6. REFERENCES

Connor, Cathy, and Daniel O’Haire. 1988. Roadside Geology of Alaska. Mountain Press Publishing Company, Missoula, Montana.

Cowlishaw, Guy, and Robin Dunbar. 2000. Primate conservation biology. University of Chicago Press. Chicago.

Forest Service (United States Department of Agriculture, Forest Service). 2012. National Best Management Practices for Water Quality Management on National Forest System Lands, Volume 1: National Core BMP Technical Guide.

Forest Service. 2008. Land and Resource Management Plan, Tongass National Forest, USDA Forest Service, Alaska Region, R10-MB-603b.

Forest Service. 2001. Ketchikan Area Soil Survey Users Guide. Tongass National Forest. Ketchikan, AK.

Forest Service. 1996. Lindenberg Timber Sale(s): Draft Environmental Impact Statement – Stikine Area. Prepared for U.S. Department of Agriculture. Tongass National Forest.

Gehrels, George E, and Henry C. Berg. 1992. Geologic Map of Southeast Alaska. United States Department of Interior, U.S. Geological Survey.



Norwacki, G., M. Shephard, P. Krosse, W. Pawuk, G. Fisher, J. Baichtal, D. Brew, E. Kissinger, and T. Brock. 2001. Ecological Subsections of Southeast Alaska and Neighboring Areas of Canada. USDA Forest Service, Alaska Region, Technical Publication R10-TP-75.

Silkworth, Darrin. 2012. E-mail from D. Silkworth to D. Cox dated 8/27/2012.

Swanston, D. 1969. Mass Wasting in Coastal Alaska. USDA Forest Service, Pacific Northwest Forest and Range Experiment Stations, USDA Institute of Northern Forestry, Juneau, Alaska. Research Paper PNW-83.

Western Regional Climate Center. 2012. Period of Monthly Climate Summary. Electronic document, http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?ak4590, accessed September 13, 2012.

http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?ak4590


Swan Lake Hydroelectric Project April 2013 FERC Project No. 2911 Version: Revised Final

Attachment 1 – Response to Agency Comments Received


Swan Lake Hydroelectric Project April 2013 FERC Project No. 2911 Page A1-1 Version: Revised Final

Item Agency / Date Assigned To Comment [some items paraphrased for brevity, see attached letter for full text] Response General Comments (applies to all study reports) 1 USFS /

February 13, 2013

FMA Page 1, 1.1 Project Description Regarding the potential for FERC boundary changes, the Forest Service requests a thorough description of the revised project boundaries and process involving revision. Changes to the project boundaries may have effects to resources on National Forest System (NFS) lands.

In the project description, the potential for FERC boundary changes is acknowledged in the event that some as yet unidentified Protection, Mitigation, & Enhancement (PME) might necessitate such a change. SEAPA feels it’s important to acknowledge this possibility. A hypothetical example could be where a measure implemented to manage shoreline erosion requires some revision of the FERC boundary because the area of concern extends past the current boundary. At this time, SEAPA has no knowledge of what PME’s might be required or whether there would be a change required in the FERC boundary or whether such changes would impact NFS lands. If such a situation arises, it would be identified prior to filing the final license amendment with FERC. Prior to filing the proposed change with FERC (revised Exhibit K maps that would accompany the amendment application) SEAPA would be talking to affected landowners to determine what additional information would be necessary. FERC would conduct a NEPA process that would analyze the effect of the Proposed Action. Proposed Resolution: Clarification will be made in the Initial Consultation Document elaborating on situations that might warrant such a change and describing the process involved in such a change

2 USFS / February 13, 2013

Page 2 Figure 1 The Forest Service requests a legend be added to this figure. The current legend states survey area and since this map is used for all resources, this is not the case. Please describe the irregular polygon surrounding Swan Lake (conveyed lands).

Figure 1 has been modified to incorporate this request.


Page 2 Figure 1 Including another figure showing the 350-ft contour and any proposed revisions to the project boundary would aid readers in understanding the project area boundary and potential effects to resources.

Figure 1 has been modified to incorporate this request


Page 2 Figure 1 Include maps showing analysis area versus project vicinity map. Many of the stated analysis areas are not logical for the resources (see analysis area comments for each resource study).

Figure 1 has been modified to clarify the area of survey. For all resources, the focus of the 2012 survey efforts were areas that could be directly affected be the proposed action. This equates to the area within the current FERC Boundary. Future Resource Reports will expand the area of analysis and will further support the NEPA process.


Page 2 Figure 1 Breaking out NFS lands and non-NFS lands within each analysis area would strengthen the document and allow for the Forest Service to evaluate NFS lands specifically

SEAPA agrees that this delineation will be necessary in the NEPA process. Future documents including the Resource Reports and the License Amendment will include this level of detail.


FMA Compliance with regulatory framework: summary of additional Executive Orders, policies, and statutes not listed. Query regarding additional State requirements

Additional information will be addressed in the ICD, and updated in future Resource Reports as appropriate.


EW None of the reports contain information sufficient to determine what will be done with debris removed from Swan Lake. The Forest Service requests additional information regarding collection, removal and disposal of debris. This information may be included in a current reservoir management plan.

SEAPA agrees that additional information will be necessary in the NEPA process. Future documents including the Resource Reports and the License Amendment will include this level of detail.



Item Agency / Date Assigned To Comment [some items paraphrased for brevity, see attached letter for full text] Response 8 USFS /

February 13, 2013

EW It is unclear where construction equipment and materials would be staged. Please provide information and figures showing plans for location of staging areas. If staging is to occur on Forest Service lands please provide at a minimum site and erosion control plans which address meeting Tongass National Forest Best Management Practices and State of Alaska water quality standards.

SEAPA agrees that additional information will be necessary in the NEPA process. Future documents including the Resource Reports and the License Amendment will include this level of detail.

Soils Study Report 52 USFS /

February 13, 2013

Page 1 1.1 Project Description See General Comments page 1. In the project description, the potential for FERC boundary changes is acknowledged in the event that some as yet unidentified Protection, Mitigation, & Enhancement (PME) might necessitate such a change. SEAPA feels it’s important to acknowledge this possibility. At this time, SEAPA has no knowledge of what PME’s might be required or whether there would be a change required in the FERC boundary or whether such changes would impact NFS lands. If such a situation arises, it would be identified prior to filing the final license amendment with FERC.


Page 3 2.1 Study Area This section is referenced in all other reports as analysis area. Please differentiate between NFS and non-NFS lands.

Text within all Study Reports has been revised to clarify that the Analysis Area was the area below the 350-foot elevation. We have revised the text to call this out of the Survey Area to avoid confusion. Per SEAPA’s 3/7/13 stakeholder meeting, additional GIS analysis will be conducted to quantify fish habitat and document existing conditions outside the existing FERC boundary, and will be assessed at the HUC-6 (Falls Creek) watershed level which will be the Analysis Area for this Resource. This information will be incorporated into the NEPA supported Resource Reports.


Page 4 3.2 Soils within the Study Area “Soil Mapping Units (SMUs) within the study area are presented in in Table 1 and Figure 2.” In general the soil mapping units are for larger scale analysis rather than project level analysis. Field verification of soils types is generally done during project planning. For this project, field identification of unstable areas is appropriate and has been observed, page 8 – photos 2 and 3. Please incorporate field data in report.

The document will be modified to incorporate the request.


Page 10 3.3 Steep Slopes and Mass Movement “MMI classes in the project area are shown in Table 1. About 15 acres (11 percent) of the study area contains MMI4.” These soil types are the most vulnerable to mass wasting. How did field work modify and/or substantiate the analysis? How was field work incorporated into identification of areas vulnerable to mass wasting?

SEAPA acknowledges the need for additional detail related to field analysis. A map will be included displaying field observed mass wasting and unstable slopes along GIS mapped MMI4 soils.


Page 11 4.1 Identified Issues and Concerns Table 2. Acres of soil inundated. Differentiate the inundated NFS lands.

The document will be modified to incorporate the request.


Page 11 4.2 Soil Removed from Productivity by Inundation or Erosion “The project will result in an irreversible loss of approximately 138 acres……All of the approximately 140 acres of soils study area would be subjected to….” Why are the numbers inconsistent?

The difference is that the area contains approximately 2 acres of water. This will be clarified in the text.



Item Agency / Date Assigned To Comment [some items paraphrased for brevity, see attached letter for full text] Response 58 USFS /

February 13, 2013

Page 11 5. Management Requirements and Mitigation Measures “No mitigation requirements or mitigation measures are identified for shoreline erosion.” The inundation will cover floodplains, include Executive Order 11988. Are there any mitigation measures for floodplain inundation?

SEAPA is committed to discussing mitigation measures associated with all relevant natural resource areas during the NEPA process. Initial discussion of these measures will be briefly touched upon in the ICD with a more detailed discussion present in the NEPA supported Resource Reports and License Amendment.


“Trees that require removal (stumps left intact) within the activity area….will follow Forest Plan Standards and Guidelines as well as BMPs. This will include….prior to removal.” At this time, the timber on NFS lands will be left standing.

SEAPA agrees that timber on NFS lands will remain standing. Clarification regarding this issue will be incorporated into the report.