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Susitna-Watana Hydroelectric Project Document
ARLIS Uniform Cover Page
Title:
Riparian study plan - 2012
SuWa 107
Author(s) – Personal:
Author(s) – Corporate:
Alaska Energy Authority
AEA-identified category, if specified:
2012 Environmental Study Plans
AEA-identified series, if specified:
Series (ARLIS-assigned report number):
Susitna-Watana Hydroelectric Project document number 107
Existing numbers on document:
Published by:
[Anchorage, Alaska] : Alaska Energy Authority, [2012]
Date published:
May 20, 2012
Published for: Date or date range of report:
Volume and/or Part numbers:
Final or Draft status, as indicated:
Document type:
Pagination:
9 p.
Related work(s):
Pages added/changed by ARLIS:
Notes:
All reports in the Susitna-Watana Hydroelectric Project Document series include an ARLIS-
produced cover page and an ARLIS-assigned number for uniformity and citability. All reports
are posted online at http://www.arlis.org/resources/susitna-watana/
Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Riparian Study Plan - 2012
Alaska Energy Authority
May 2012
Susitna-Watana Hydroelectric Project FERC #14241 Alaska Energy Authority
2012 Riparian Study—May 20, 2012 1
RIPARIAN STUDY PLAN—2012
INTRODUCTION
The Alaska Energy Authority (AEA) is preparing a License Application that will be submitted to the
Federal Energy Regulatory Commission (FERC) for the Susitna-Watana Hydroelectric Project (Project)
using the Integrated Licensing Process (ILP). The Project is located on the Susitna River in the south-
central region of Alaska. The Susitna River drains the Talkeetna Mountains and portions of the Alaska
Range (Clearwater Mountains) and flows for approximately 300 miles before emptying into upper Cook
Inlet. The Project’s dam site would be located at River Mile (RM) 184 and a reservoir would be created
upstream of the dam. One or two power transmission lines and an access road also would be constructed.
The results of Riparian Study will provide baseline information needed to support FERC’s National
Environmental Policy Act (NEPA) analysis for the Project license
Construction and operation of the Project, as described in the Pre-application Document (PAD; AEA
2011), would alter the natural flow regime of the Susitna River. This study plan outlines the objectives
and methods for mapping and characterizing existing vegetation and wildlife habitats in riparian areas
downstream from the proposed dam and will serve as the baseline from which predictive models will be
developed to assess likely changes in riparian ecosystems downstream of the proposed dam. A thorough
understanding of how the proposed Project activities would affect hydrologic processes and riparian
ecosystems downstream of the dam will be critical for developing best management practices, assessing
potential impacts to wildlife, and preparing adequate FERC documentation of Project effects.
STUDY OBJECTIVES
The goal of the Riparian Study is to characterize and map the local-scale riparian ecosystems (riparian
ecotypes) and wildlife habitat types in the Project study area, and assess the extent to which the proposed
Project will affect riparian processes and function. The overall (multi-year) objectives of the Riparian
Study are to:
Identify and map riparian ecotypes and wildlife habitats downstream from the Watana Dam site;
Characterize the physical and ecological processes downstream from the Watana Dam site that
are likely to affect riparian areas;
Quantify the potential impacts to riparian areas due to Project construction and operations,
including potential changes to riparian ecotypes and wildlife habitats, riparian processes, and
vegetation successional pathways;
Predict potential changes in riparian ecotypes and wildlife habitats that would result from
alterations in instream flow, ice processes, and riverine geomorphology;
Develop potential protection, mitigation, and enhancement (PME) measures to address Project-
related impacts to riparian areas, riparian processes, and vegetation successional pathways; and
Develop and implement the 2013–2014 Riparian Study Plan.
The interim study objectives for 2012 are to conduct field ground-verification surveys and begin work on
a current map of riparian ecotypes and wildlife habitats in riparian areas downstream of the proposed
dam.
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2012 Riparian Study—May 20, 2012 2
STUDY AREA
The Riparian Study area will overlap with the vegetation, wildlife habitat, and wetlands mapping study
areas near the proposed dam site, but the main focus for the Riparian Study will be on riparian areas along
the Susitna River and its tributaries below the dam site, which are expected to be altered by changes in
stream flow, ice processes, and riverine geomorphology from construction and operation of the proposed
dam.
The study area for the mapping of riparian ecotypes and wildlife habitats in the riparian study will be
formally defined in consultation with management agency personnel over the course of developing the
2013–2014 study plan, but we expect the study area will include those riparian areas downstream of the
proposed dam site to a point at which the effects of altered flow regimes expected in the Susitna River
would not be measureable or would be overridden by the effects of tidal fluctuations from Cook Inlet.
This downstream location will be determined following analysis of the results of the 2012 instream flow
studies. In 2012, the riparian study will focus on those downstream areas in which altered flow regimes
are most likely to occur, including from the proposed dam site downstream to the town of Willow (Figure
1). Eventually (in 2013 and 2014) the width of the study area for the mapping of successional vegetation
in the riparian study will cover all riverine areas in the active floodplain of the Susitna River out to the
estimated limits of 100-year flood events (plus a buffer area of at least 800 meters, pending input from
management agency personnel). The estimated limits of 100-year flood events will be determined in
analyses of data from the 2012 instream flow studies. In 2012, the riparian study area will extend laterally
from approximately the edge of flowing waters in the Susitna River to 200 meters into adjacent upland
terrain .
EXISTING INFORMATION
A number of riparian and vegetation mapping resources for the Project area were identified as part of the
preparation of the PAD (AEA 2011), which was prepared, in part, to identify data gaps and prioritize the
environmental study efforts for the Project. Of primary importance to the Riparian Study are the previous
vegetation mapping and vegetation successional dynamics studies by McKendrick et al. (1982), Collins
and Helm (1997), and Helm and Collins (1997). These previous studies will serve as a baseline for
developing a sampling scheme and providing a conceptual framework upon which to build our vegetation
succession classification and predictive models for assessing the downstream effects of the proposed
Project on riparian habitats.
Current, high-resolution orthophoto imagery, which will be used for the on-screen mapping work, is
available for most of the Riparian Study area. Moderate-resolution imagery (to support the field studies in
2012) will fill the remaining gaps in the study area. Additional high-resolution aerial photography or
satellite imagery for the Project area is expected to be acquired in summer 2012; that imagery likely will
be available in late 2012.
METHODS
We propose an integrated approach to the mapping of riparian ecotypes and wildlife habitats based on
methods developed for Ecological Land Surveys (ELS) studies conducted in tundra, boreal forest, and
coastal regions in Alaska over the past 15 years (see Jorgenson et. al. 2002 for an example study in south-
central Alaska). This integrated mapping approach involves mapping terrain units such as vegetation,
geomorphology, and surface-form type, and then combining them into units with ecological importance
(in this case riparian ecotypes and wildlife habitats, see below). The integrated terrain unit (ITU) mapping
methods are flexible and well suited to the use of existing GIS data layers for terrain units (when
available).
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2012 Riparian Study—May 20, 2012 3
The method of combining various ITUs allows for the preparation of a number of thematic maps
depending on the specific needs of an individual study. For the Riparian Study, a riparian ecotype map
and a wildlife habitat map, each based on the best combinations of ITUs, will be prepared. The mapping
of wildlife habitats in the Riparian Study will be conducted in coordination with the researchers
conducting the Vegetation and Wildlife Habitat Mapping Study to derive a single set of wildlife habitats
that apply project-wide.
TASK 1: COMPILE AND REVIEW EXISTING INFORMATION TO PREPARE MAPPING
MATERIALS
Data sources that may be used for the mapping of riparian ecotypes and wildlife habitats include
vegetation mapping and vegetation succession studies conducted in the Susitna River drainage by
McKendrick et al. (1982), Collins and Helm (1997), Helm and Collins (1997); soil surveys; digital
elevation data; the National Hydrography Dataset (USGS 1999); and other map products that may have
been produced for the area as part of other studies. These data will be compiled and reviewed and, if
possible, included as a map layer in ArcGIS to assist the mapping effort.
The available, high- and moderate-resolution aerial imagery for the project area will be acquired and
evaluated for quality and geodetic control. As noted above, for those portions of the study area that are
not covered by high-resolution aerial imagery (needed for mapping), moderate-scale imagery will be used
to support the field sampling efforts in summer 2012.
TASK 2: COMPLETE PRELIMINARY MAPPING
If time permits, prior to the 2012 field season, we will initiate the mapping of preliminary local-scale
riparian ecosystems (riparian ecotypes) using the current aerial imagery available for the study area. As
noted above, we propose to map riparian ecotypes using an ITU approach. We propose a minimum
mapping size of 1 acre for terrestrial polygons and 0.25 acres for waterbodies. ITU map polygons will be
attributed with geomorphology (e.g., Braided Active Overbank Deposit); surface form (e.g., Mid-channel
Bar); vegetation class (e.g., Low Willow Scrub), and successional stage (e.g., young poplar, old poplar).
Riparian vegetation in this study will be mapped to the Level IV of the Alaska Vegetation Classification
(Viereck, et al. 1992) with adjustments, as needed, for early successional riparian stages following Helm
and Collins (1997). The ITU parameters can be displayed individually to produce distinct
geomorphology, surface form, and successional vegetation maps. The ITU codes will be aggregated into
preliminary riparian ecotypes based on the combination of the four ITUs noted above that best represents
the local-scale riparian habitats in the areas mapped.
TASK 3: COMPLETE GROUND VERIFICATION
We plan to use the preliminary mapping of riparian ecotypes to design a stratified random sampling
scheme to preselect potential study sites within riparian habitats, including at least one representative site
for each riparian habitat type. If this is not possible (because of time constraints for example), we will
preselect study sites based on aerial imagery signatures. In the selection of study sites, we also will
coordinate with researchers conducting the instream flow, ice processes, and riverine geomorphology
studies to try to co-locate study sites, as much as possible, so that the measured riparian habitat
parameters can be related to existing conditions for instream flow, ice processes, and geomorphology on a
site-by-site basis. These coordinated baseline data will help in the later stages of the Riparian Study, in
which predictions of changes in riparian habitats due to construction and use the proposed dam will be
made. We will complete the 2012 ground verification in two phases. In Phase 1, we will work with the
Instream Flow Study Project Manager to conduct a helicopter-assisted reconnaissance of of the Susitna
River from Talkeetna to Willow during mid-June. The goal of the reconnaissance survey is to determine
the feasibility of re-locating field sites originally established by McKendrick et al. (1982) and Collins and
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2012 Riparian Study—May 20, 2012 4
Helm (1997) for potential re-sampling, and to identify new study sites for additional sampling. Based on
the results of the reconnaissance survey, we will adjust our sampling scheme and prepare for the second
phase of field sampling.
Phase 2 of the field sampling will occur in late June–early July and will include sampling of preselected
study sites in conjunction with the data collection efforts for the Instream Flow Study. Data will be
recorded digitally in the field using a standardized data entry form designed to link directly to a relational
database (Microsoft Access). We will sample riparian habitats using two types of transects: verification
transects and intensive transects. Verification transects are designed for rapid map verification and
description of ecosystem components. Circular plots of 10 m radii will be sampled along verification
transects, at which mapped variables (e.g., vegetation, successional stage, geomorphology, surface form)
will be categorized into classes only; detailed field measurements will not be made. Along intensive
transects, circular study plots will be a minimum of 500 m2 in forested areas and 50 m2 in non-forest
areas. On intensive transects, we will collect detailed data on vegetation structure, successional dynamics,
plant phenology, site variables, soils, hydrology, and specific wildlife habitat characteristics or sign. The
shape of the study plots on both verification and intensive transects may vary depending on the shape of
the vegetation stand being sampled. We will follow field methods provided by McKendrick et al. (1982),
Collins and Helm (1997), and Helm and Collins (1997). Data attributes collected in the field on intensive
transects will include:
Geo-referenced plot locations (<3-m accuracy);
Vegetation cover by species in each of 7 height categories (0.0–0.1 m, 0.4–1 m, 1–2 m, 2–4 m, 4–
8 m, 8–16 m, and >16 m) based on transect point counts;
Ages (cross section cuttings or cores) and height of dominant woody plants;
Density by size class (<4 cm, <0.4 m, 0.4–2 m, 2–4 m, and >4 m DBH); and size-class groupings
(<4 m and >4 cm DBH; and >4 m and <4 cm DBH); or other size class or vegetation structure
classes necessary for browse evaluations;
Crown dominance for each woody species;
Phenological attributes for selected plant species;
Site variables, including physiography, geomorphic unit, surface form, elevation, aspect, and
slope;
Shallow soil pits for drainage and soil moisture; soil hydrologic variables, including depth of
water above or below ground surface, depth to saturated soil, pH, and electrical conductivity
(EC); and soil depositional profiles;
Vegetation structure and plant community composition to identify vegetation types; and
Wildlife sign such as browse marks, nests, dens, droppings, singing birds, carcasses, tracks,
burrows.
TASK 4: POST-FIELD MAPPING AND ANALYSIS
After the field season, we will begin revising the preliminary ITU mapping so that it accurately reflects
the field ground-verification data collected in summer 2012. This on-screen mapping in GIS will be an
on-going process that may not be completed for the full mapping study area until 2014. Once substantial
progress has been made on the ITU mapping for 2012, however, we will prepare a preliminary set of
riparian ecotypes and wildlife habitat types. Riparian ecotypes will be derived as described above under
Task 2: Complete Preliminary Mapping, and wildlife habitat types will be derived as described in the
Vegetation and Wildlife Habitat Mapping Study Plan—2012. The riparian wildlife habitats will be
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2012 Riparian Study—May 20, 2012 5
reviewed by ABR wildlife biologists working on the Project and any revisions necessary will be made
before preparing the Technical Memorandum for 2012 (see Reporting below).
After the ITU mapping has been updated, a number of summary statistics will be generated using
standard ArcGIS geoprocessing techniques, including total acreages of ITU components, riparian
ecotypes and wildlife habitats within the study area. This information will be included in the Technical
Memorandum describing the results of the 2012 mapping study (see Reporting below).
REPORTING
The primary deliverables to be prepared in 2012 include (1) this study plan describing the work to be
performed in 2012, (2) the Proposed and Revised Study Plans for work in 2013–2014, (3) copies of field
data and GIS map products, and (4) a Technical Memorandum describing the progress and results of the
2012 Riparian Study (see Products below).
In the Technical Memorandum, we will summarize the results of the 2012 Riparian Study. The report will
include descriptions of the riparian ecotypes and wildlife habitat types identified; a summary table
(acreages) of the riparian ecotypes and wildlife habitat types represented in the 2012 mapping effort; field
plot photos including site, ground, and soil photographs; and recommendations for the 2013 field survey
effort.
A digital copy of the preliminary ecotype and habitat mapping will be provided as a separate deliverable
in ArcGIS format, and will include supporting metadata documentation.
LOGISTICAL SUPPORT AND HEALTH AND SAFETY
The field survey will be performed using the following schedule, transportation, and personnel:
Phase 1: one field crew of 2-3 scientists will comprise the field work, and will include 6 days of
field reconnaissance surveys from 20–25 June, 2012.
Phase 2: two field crews comprised of 2 scientists each will perform the field survey over a 9-day
period from 26 June–4 July 2012.
Both phases of field work will require one R-44 Raven 2 helicopter with approximately 6 hours
of flight time required each day.
A Health, Safety, and Environmental Plan will be prepared prior to the field effort that will
include:
Project Safety Risk Assessment and Plan: This consists of a matrix that describes specific
potential hazard/risk categories; the methods to be used to minimize risks; and responses to
hazards.
Field Communication Plan: This plan identifies the field personnel, the physical location of the
field party, and contact information (telephone, fax, email, satellite phone, cell phone, or radio).
Emergency Contact form and Emergency Medical form: All field personnel complete (or update)
these forms prior to beginning field work.
All field personnel will have, at a minimum, CPR and Basic First Aid training prior to commencing
fieldwork. Discussions regarding safety concerns raised by field personnel will be documented on a
Safety Concerns or Minor Safety Incident Report. Should a minor safety incident occur, an ABR Safety
Concerns or Minor Safety Incident Report will be filled out by the staff member(s) involved in the
incident and reviewed by the Field Project Leader (FPL) and Project Manager (PM). After returning from
the field, all forms will be submitted to the ABR Safety Group for review and a copy will be stored in the
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2012 Riparian Study—May 20, 2012 6
project’s safety folder. A post-field safety review will be conducted to review all safety concerns or minor
incidents, identify any problems areas where safety training or planning can be improved, and those
resolutions will be communicated to the PI/FPL and the staff involved in the incident.
A major safety incident (defined as an accident that required removal of the staff member from the field,
hospitalization, or other responses that would initiate an OSHA or Workman’s Compensation report) will
be reported immediately to their PM/FPL and Tom DeLong, ABR’s Office/Contracts Manager. A
detailed report on the safety incident, the response, and any actions required will be prepared by the PM
and submitted to the ABR Safety Group for review. As with the minor incident reports, this report will be
reviewed during the post-field audit and any appropriate changes in planning, training, or response will be
undertaken and documented with a follow-up addendum to the original report.
NEXUS BETWEEN PROJECT AND RESOURCE TO BE STUDIED AND HOW THE RESULTS
WILL BE USED
Project operations will affect riparian habitats downstream from the proposed Watana Dam site. Project
effects will include direct, indirect, and cumulative effects to riparian habitats. Through this study, ABR
biologists will characterize and quantify riparian habitats and successional vegetation stages downstream
from the dam site, and will evaluate potential direct, indirect, and cumulative effects of Project operations
on riparian habitats. This is a multi-year study that will begin in 2012 and will continue in 2013 and 2014.
Upon a complete assessment of the Project area, mitigation alternatives will be developed from the data to
address adverse Project-induced impacts.
This study addresses the following issues identified in the PAD (AEA 2011):
Losses of vegetation and wetland communities and productivity from reservoir inundation and the
development of other Project facilities (direct effects).
Changes to vegetation and wetland communities along access roads, transmission corridors, and
reservoir edges due to alteration of solar radiation, temperature moderation, erosion and dust
deposition, reservoir fluctuation, pathogen dispersal and abundance.
Potential changes in wetlands, wetland functions, riparian vegetation, and riparian succession
patterns related to altered hydrologic regimes below the dam.
The results of this study will provide an analysis of the number of acres and distribution of riparian
habitat types to provide a basis for riparian habitat impact analysis and development of mitigation
measures. Wildlife use and riparian habitat functions are related to the types and successional stages of
riparian vegetation communities; therefore results of this study will be necessary to evaluate baseline and
future wildlife use in the Project area. The wildlife habitat types mapped in this study also will provide
the basis for an evaluation of habitat use by wildlife in the Project area, which then will be used to
evaluate impacts to wildlife habitats for the specific bird and mammal species of concern in the Project
area. Additionally, the results of this study will be used to help facilitate the Rare Plant Study and
Invasive Plant Study (e.g., riparian habitat types where rare or invasive plants are likely to be found will
be identified to help to focus future field efforts).
PRODUCTS
Study products to be delivered in 2012 will include:
Development of final 2012 Riparian Study Plan. The study plan for work in 2012 will be finalized
through consultation with AEA, the Botanical Resources Program Lead, the Wildlife Resources Program
Lead, resource management agencies, and other licensing participants. The Study Project Manager for the
Riparian Study will participate in the Technical Working Group meetings as the technical lead for this
study and will prepare materials and revise the study plan accordingly.
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2012 Riparian Study—May 20, 2012 7
2013–2014 Riparian Study Plan. The 2013–2014 study plan will be developed with input received
during the Technical Working Group Meetings through the formal FERC ILP study plan process. The
Study Project Manager for the Riparian Study will participate in the Technical Working Group meetings
and assist the Botanical Resources Program Lead in developing the draft and final Proposed Study Plans
and draft and final Revised Study Plans.
Draft Technical Memoranda. A draft technical memorandum will be prepared in mid-summer 2012
summarizing the progress of the 2012 field studies and mapping work.
Geospatially-referenced ground-verification data. A geospatially-referenced relational database of
historic data and data collected during the 2012 field season, including representative photographs of
riparian habitats will be prepared. This database will form the basis for additional data collection efforts
in 2013 and 2014. Naming conventions of files and data fields, spatial resolution, map projections, and
metadata descriptions will meet the data standards to be established for the Project.
Riparian ecotype and wildlife habitat maps in ArcGIS software. Draft riparian ecoptype and wildlife
habitat maps will be developed and delivered according to the schedule indicated below. The ecotype and
habitat maps will continue to be developed during 2013 and 2014 so as to cover the full mapping study
area. Naming conventions of files and data fields, spatial resolution, map projections, and metadata
descriptions will meet the data standards to be established for the Project.
Final 2012 Technical Memorandum. A final technical memorandum summarizing all of the 2012 study
results will be prepared in winter 2012. Summary results and evaluation of the 2012 data may lead to
development of additional data collection or evaluation techniques in subsequent years. In the
memorandum, the status of the study will be assessed and any technical problems that have occurred will
be identified, thereby allowing for refinement of the study methods in 2013–2014.
SCHEDULE
The following schedule is for the 2012 scope of work. The schedule for the 2013–2014 work will be
developed in consultation with AEA during the 2013–2014 study planning process.
Final 2012 Riparian Study Plan — 20 May 2012
Draft 2013–2014 Riparian Proposed Study Plan — May 23, 2012
Final 2013–2014 Riparian Proposed Study Plan — June 30, 2012
Draft Technical Memorandum — July 31, 2012
Draft 2013–2014 Riparian Revised Study Plan — September 15, 2012
Final 2013–2014 Riparian Revised Study Plan — October 31, 2012
Geospatially-referenced relational database of field data — November 30, 2012
Draft (to date) riparian ecotype and wildlife habitat maps in ArcGIS software — November 30,
2012
Final Technical Memorandum — November 30, 2012
Draft 2013–2014 Riparian Study Plan (based on FERC approval) — December 2012
REFERENCES
Alaska Energy Authority (AEA). 2011. Pre-Application Document: Susitna-Watana Hydroelectric Project
FERC Project No. 14241. December 2011. Prepared for the Federal Energy Regulatory Commission
by the Alaska Energy Authority, Anchorage, Alaska.
Susitna-Watana Hydroelectric Project FERC #14241 Alaska Energy Authority
2012 Riparian Study—May 20, 2012 8
Collins, W.B., and D.J. Helm. 1997. Moose, Alces alces, habitat relative to riparian succession in the
boreal forest, Susitna River, Alaska. Canadian Field-Naturalist 111:567-574.
Helm, D. J., and W. B. Collins. 1997. Vegetation succession and disturbance on a boreal forest
floodplain, Susitna River, Alaska. Canadian Field-Naturalist 111:553–566.
Jorgenson, M. T., J. E. Roth, M. Emers, S. F. Schlentner, D. K. Swanson, E. R. Pullman, J. S. Mitchell,
and A. S. Stickney. 2003. An ecological land survey in the Northeast Planning Area of the National
Petroleum Reserve–Alaska, 2002. Report for ConocoPhillips Alaska, Inc., Anchorage, AK and
Anadarko Petroleum Corp, Anchorage AK, by ABR, Inc., Fairbanks, AK. 128 pp
McKendrick, J. D., W. Collins, D. Helm, J. McMullen, and J. Koranda. 1982. Susitna Hydroelectric
Project environmental studies, Phase I final report, Subtask 7.12—Plant ecology studies. Report
prepared by University of Alaska, Agricultural Experiment Station, Palmer, for Alaska Power
Authority, Anchorage. 124 pp. + appendix. [APA Doc. No. 1321]
USGS (U. S. Geological Survey). 1999. National Hydrography Dataset—Medium resolution. Prepared by
the U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency. Reston,
Virginia. Accessed online: http://nhd.usgs.gov.
Viereck, L. A., C. T. Dyrness, A. R. Batten, and K. J. Wenzlick. 1992. The Alaska Vegetation
Classification. Pacific Northwest Research Station, U.S. Forest Service, Portland, OR. Gen. Tech.
Rep. PNW-GTR-286. 278 pp.
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