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Susitna-Watana Hydroelectric Project Document
ARLIS Uniform Cover Page
Title:
Mercury assessment and potential for bioaccumulation study, Study plan
Section 5.7 : Initial study report
SuWa 207
Author(s) – Personal:
Author(s) – Corporate:
URS Corporation, Tetra Tech, Inc.
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Draft initial study report
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Series (ARLIS-assigned report number):
Susitna-Watana Hydroelectric Project document number 207
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[Anchorage : Alaska Energy Authority, 2014]
Date published:
February 2014
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Alaska Energy Authority
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Study plan Section 5.7
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Draft
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ix, 60 p.
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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)
Mercury Assessment and Potential for
Bioaccumulation Study
Study Plan Section 5.7
Initial Study Report
Prepared for
Alaska Energy Authority
Prepared by
URS Corporation/Tetra Tech, Inc.
February 2014 Draft
INITIAL STUDY REPORT MERCURY ASSESSMENT AND POTENTIAL FOR BIOACCUMULATION STUDY (5.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page i February 2014 Draft
TABLE OF CONTENTS
Executive Summary .................................................................................................................... vii
1. Introduction............................................................................................................................ 1
2. Study Objectives .................................................................................................................... 2
3. Study Area .............................................................................................................................. 2
4. Methods and Variances in 2013 ............................................................................................ 2
4.1. Summary of Available Information ............................................................................... 2
4.2. Collection and Analyses of Soil, Vegetation, Water, Sediment, Sediment Pore Water,
Piscivorous Birds and Mammals, and Fish Tissue Samples for Mercury ..................... 3
4.2.1. Vegetation ............................................................................................................... 3
4.2.2. Soil .......................................................................................................................... 3
4.2.3. Water ....................................................................................................................... 4
4.2.4. Sediment and Sediment Porewater ......................................................................... 7
4.2.5. Piscivorous Birds and Mammals ............................................................................ 8
4.2.6. Fish Tissue .............................................................................................................. 9
5. Results ................................................................................................................................... 11
5.1. Summary of Available Information ............................................................................. 11
5.1.1. APA Susitna Hydroelectric Project/USGS ........................................................... 11
5.1.2. Alaska Department of Environmental Conservation ............................................ 12
5.1.3. USGS (Frenzel 2000) ............................................................................................ 12
5.1.4. Western Airborne Contaminants Assessment Project .......................................... 13
5.1.5. Jewett and Duffy (2007) ....................................................................................... 14
5.1.6. Geologic Data ....................................................................................................... 14
5.2. Vegetation .................................................................................................................... 15
5.3. Soil ............................................................................................................................... 15
5.4. Water ............................................................................................................................ 16
5.5. Sediment and Sediment Porewater............................................................................... 16
5.6. Piscivorous Birds and Mammals .................................................................................. 16
5.7. Fish Tissue ................................................................................................................... 17
5.7.1. Lake Trout ............................................................................................................. 17
5.7.2. Longnose Sucker ................................................................................................... 17
5.7.3. Dolly Varden ......................................................................................................... 18
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5.7.4. Arctic Grayling ..................................................................................................... 18
5.7.5. Burbot ................................................................................................................... 18
5.7.6. Slimy Sculpin ........................................................................................................ 18
5.7.7. Whitefish ............................................................................................................... 18
6. Discussion ............................................................................................................................. 19
6.1. Current Status of the Study Effort ................................................................................ 19
6.1.1. Summary of Available Information ...................................................................... 19
6.1.2. Vegetation and Soil ............................................................................................... 19
6.1.3. Water ..................................................................................................................... 20
6.1.4. Sediment and Sediment Porewater ....................................................................... 20
6.1.5. Piscivorous Birds and Mammals .......................................................................... 20
6.1.6. Fish Tissue ............................................................................................................ 21
7. Completing the Study .......................................................................................................... 21
8. Literature Cited ................................................................................................................... 21
9. Tables .................................................................................................................................... 24
10. Figures .................................................................................................................................. 39
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LIST OF TABLES
Table 4.2-1. Sampling Parameters and Media ............................................................................. 25
Table 4.2-2. Vegetation and Soil Sample Locations.................................................................... 26
Table 4.2-3. Baseline Water Quality Monitoring Sites for Total and Dissolved Mercury .......... 28
Table 4.2-4. Focus Area Water Monitoring Sites for Total and Methylmercury ........................ 28
Table 5.1-1. Historic Mercury Concentrations at Gold Creek (PRM 140.1) ............................... 29
Table 5.1-2. Historic Mercury Concentrations at Susitna at Parks Highway East (PRM 87.8) .. 30
Table 5.1-3. Historic Mercury at Susitna Station (PRM 29.9) .................................................... 31
Table 5.1-4. ADEC Mercury Statewide Data (ng/g ww)............................................................. 32
Table 5.1-5. ADEC Mercury Data from Susitna Watershed ....................................................... 33
Table 5.1-6. Mercury in Cook Inlet Sediments and Slimy Sculpin (Frenzel 2000) .................... 34
Table 5.1-7. Mercury Partitioning in Cook Inlet Sediments and Slimy Sculpin (Frenzel 2000) 34
Table 5.1-8. WACAP Data for Lichen Samples .......................................................................... 35
Table 5.1-9. WACAP Data for Alaska Fish ................................................................................ 35
Table 5.2-1. Plant Species Observed and Collected at Each Sample Site ................................... 36
Table 5.3-1. Results of General Soil Characteristics ................................................................... 37
Table 6.1-1 Mercury in Soil and Vegetation (Friedli et al. 2007) ................................................ 38
LIST OF FIGURES
Figure 3-1. Water Quality Sample Locations .............................................................................. 40
Figure 4.2-1. Vegetation and Soil Sampling Locations ............................................................... 41
Figure 4.2-2. Vegetation and Soil Sample Location: Site 1 ........................................................ 42
Figure 4.2-3. Vegetation and Soil Sample Location: Site 2 ........................................................ 43
Figure 4.2-4. Vegetation and Soil Sample Location: Site 3 ........................................................ 44
Figure 4.2-5. Vegetation and Soil Sample Location: Site 4 ........................................................ 45
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Figure 4.2-6. Vegetation and Soil Sample Location: Site 5 ........................................................ 46
Figure 4.2-7. Vegetation and Soil Sample Location: Site 6 ........................................................ 47
Figure 4.2-8. Vegetation and Soil Sample Location: Site 7 ........................................................ 48
Figure 4.2-9. Vegetation and Soil Sample Location: Site 8 ........................................................ 49
Figure 4.2-10. Vegetation and Soil Sample Location: Site 9 ...................................................... 50
Figure 4.2-11. Vegetation and Soil Sample Location: Site 10 .................................................... 51
Figure 4.2-12. Overview of Focus Area Sampling Locations ..................................................... 52
Figure 4.2-13. Map of Sediment/Porewater Sampling Locations................................................ 52
Figure 4.2-14. Sediment and Porewater Sample Locations for Goose and Jay Creeks ............... 54
Figure 4.2-15. Sediment and Porewater Sample Locations for Kosina Creek and Oshetna River
....................................................................................................................................................... 55
Figure 4.2-16. Fish Tissue Sample Collection Locations ............................................................ 56
Figure 5.1-1. ADEC Fish Tissue Sample Collection Locations .................................................. 57
Figure 5.1-2. USGS (Frenzel 2000) Sample Locations ............................................................... 58
Figure 5.7-1. Lake Trout Fork Length and Age (Burr 1987) ....................................................... 59
Figure 5.7-2. LNS Fork Length and Age in the Upper Susitna (APA 1984) .............................. 59
Figure 5.7-3. Arctic Grayling Fork Length and Age in the Upper Susitna (APA 1984) ............. 60
Figure 5.7-4. Round Whitefish Fork Length and Age in Middle Susitna (APA 1984) ............... 60
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LIST OF ACRONYMS, ABBREVIATIONS, AND DEFINITIONS
Abbreviation Definition
AEA Alaska Energy Authority
ADEC Alaska Department of Environmental Conservation
ADF&G Alaska Department of Fish and Game
APA Alaska Power Authority
BrCl bromine monochloride
BW body weight
Cm centimeter
D daily intake
DO dissolved oxygen
Dw dry weight
EFDC Environmental Fluid Dynamics Code
EPA U.S. Environmental Protection Agency
FERC Federal Energy Regulatory Commission
ft. feet
FL fish length
G gram
GAAR Gates of the Arctic National Park
GPS global positioning system
HDPE high density polyethylene
Hg mercury
ISR Initial Study Report
K Kelvin
Kg kilogram
LNS longnose suckers
M million
mm millimeters
m2 square meters(s)
MeHg methylmercury
Ng nanograms
ng/g nanograms per gram
ng/m2/yr nanograms per square meter per year
NOAA National Oceanic and Atmospheric Administration
NOAT Noatak National Preserve
NS Not sampled
NWIS National Water Information System
Project Susitna-Watana Project
PRM Project River Mile
QAPP Quality Assurance Project Plan
QA/QC quality assurance/quality control
RSP Revised Study Plan
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Abbreviation Definition
SAP Sampling and Analysis Plan
SPD Study Plan Determination
TOC total organic carbon
Ww wet weight
µg microgram
µg/kg microgram per kilogram
µg/L micrograms per liter
µm micrometer
USGS U.S. Geological Survey
WACAP Western Airborne Contaminants Assessment Project
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EXECUTIVE SUMMARY
Mercury Assessment and Potential for Bioaccumulation Study 5.7
Purpose The objective of the study is to quantify the current mercury concentrations in
the proposed inundation zone of the reservoir, estimate the potential changes
to mercury concentrations post-impoundment, and the impacts these changes
will have on the ecosystem.
Status This study was initiated in 2013. Available mercury information has been
summarized, including data collection from the 1980s Alaska Power
Authority Susitna Hydroelectric Project, and existing geologic information to
determine if a mineralogical source of mercury exists within the inundation
area. All of the planned vegetation and soil samples were collected. All
planned water, sediment and sediment pore samples were collected except
those identified below (2013 Variances). The Study Plan required feathers and
fur be collected during the wildlife surveys, however none were obtained.
This resulted in a modification to the Study Plan. All of the planned fish tissue
sampling activities occurred except variations in the number and species of
some fish indicated for collection. The data collected as part of this study is
currently undergoing a quality review and modeling of the results is on-going.
Study
Components
This study consists of the following study components:
•Summarize available information to determine if a mineralogical source of
mercury exists within the inundation area.
•Collect and analyze background concentrations for mercury in vegetation,
soil, water, sediment, sediment pore water; and piscivorous birds and
mammals, and fish tissue samples for mercury.
•Use the water quality model to predict where in the reservoir conditions (pH,
dissolved oxygen, turnover) are likely to be conducive to methylmercury
formation.
•Utilize specialty models to predict potential fish methylmercury
concentrations.
•Assess potential pathways for mercury movement from different areas of
methylmercury formation to the surrounding environment.
2013 Variances AEA implemented the methods as described in the Study Plan with the
exception of the following variances. The significance of these variances is
discussed within the ISR.
• The Study Plan indicates that EPA Method 1631 would be used for
total mercury analysis in soil. This method recommends extraction
protocols for mineral soils; however, the samples collected contained a
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FERC Project No. 14241 Page viii February 2014 Draft
Mercury Assessment and Potential for Bioaccumulation Study 5.7
significant fraction of peat and organic material. To accommodate this,
the samples were analyzed using two different extraction methods, and
both results will be reported. See subsection 4.2.2.1 in this ISR.
• Table 5.7-5 in Study Plan Section 5.7.4.2.3 summarizes the proposed
water sampling locations for mercury analysis in water. PRM 225.5
(Susitna near Cantwell) could not be sampled due to limited access by
helicopter. The sample site was relocated to PRM 235.2 (Susitna River
adjacent to Oshetna Creek). See subsection 4.2.3.4 in this ISR.
• Study Plan Section 5.5.4.4.2 indicated that water samples would be
collected at three locations along each transect for mainstem samples.
Water samples were collected from just one position in the river due to
limited access by wading at PRM 233.2 (Susitna River adjacent to
Oshetna Creek) and 187.2 (Susitna at Watana Dam site). See
subsection 4.2.3.4 in this ISR.
• Study Plan Attachment 5-1 indicated that an Ekman dredge or
modified Van Veen grab sampler would be deployed from a boat;
however, this approach was impractical and other approaches
(wading) were employed (as identified in the QAPP). See subsection
4.2.4.1 in this ISR.
• Study Plan Section 5.7.4.6.1 indicated seven to ten of each target
species of fish would be collected; however, additional fish were
collected for some species (Arctic grayling and round whitefish). The
Study Plan also indicated that only adult fish would be collected;
however, some juvenile specimens were incidentally collected. While
most were released, if a juvenile fish was captured accidentally and
died, it was analyzed.
• The Study Plan indicated that all fish would be speciated; however,
two fish could not be successfully speciated. Also, it was not possible
to successfully extract otoliths from all the fish captured, however,
sufficient otolith data is available from other studies.
• The Study Plan required determination of the sex and sexual maturity
of the fish, however, determination of gender for the fish proved to be
problematic in the field, and the sex of only 12 fish was determined.
The proposed field collection period for fish was from August to
September; however, the sample period was extended into October to
obtain sufficient sample size. Polyethylene sheets rather than Teflon
sheets were used for the fish when placed in the sample bag. See
subsection 4.2.6.1.
Steps to
Complete the
As explained in the cover letter to this draft ISR, AEA’s plan for completing
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FERC Project No. 14241 Page ix February 2014 Draft
Mercury Assessment and Potential for Bioaccumulation Study 5.7
Study this study will be included in the final ISR filed with FERC on June 3, 2014.
Highlighted
Results and
Achievements
Most of the proposed sampling for the project was successfully completed,
and the results are being evaluated at this time. Going forward it is anticipated
that additional, reduced sampling will occur to extend and complete the
necessary data set for the existing mercury concentrations.
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1. INTRODUCTION
On December 14, 2012, Alaska Energy Authority (AEA) filed with the Federal Energy
Regulatory Commission (FERC or Commission) its Revised Study Plan (RSP), which included
58 individual study plans (AEA 2012). Included in the Study Plan was the Mercury Assessment
and Potential for Bioaccumulation Study, Section 5.7. Section 5.7 focuses on determining the
current concentrations and methylation rates for mercury in the study area, and what changes
could occur with construction of the Susitna-Watana Project (Project) reservoir.
On February 1, 2013, FERC staff issued its study determination (February 1 SPD) for 44 of the
58 studies, approving 31 studies as filed and 13 with modifications. On April 1, 2013 FERC
issued its study determination (April 1 SPD) for the remaining 14 studies; approving one study
as filed and 13 with modifications. Study Plan Section 5.7 was one of the 13 approved with
modifications. In its April 1 SPD, FERC recommended the following:
Use of Harris and Hutchinson and EFDC Models for Mercury Estimation
We recommend that AEA use the more sophisticated Phosphorus Release Model to
predict peak methylmercury levels in fish tissue, regardless of the outcome of the
other two models.
Mercury Effects on Riverine Receptors
We recommend that AEA include likely riverine receptors (i.e., biota living
downstream of the reservoir that may be exposed to elevated methyl mercury
concentrations produced in the reservoir and discharged to the river) as part of the
predictive risk analysis. The additional study element would have a low cost
(section 5.9(b)(7)) because AEA would simply add consideration of additional
receptors to the existing analysis. This information is necessary to evaluate
potential project effects downstream of the reservoir (section 5.9 (b)(5)).
In accordance with the April 1 SPD, AEA has adopted the FERC requested modifications.
Following the first study season, FERC’s regulations for the Integrated Licensing Process (ILP)
require AEA to “prepare and file with the Commission an initial study report describing its
overall progress in implementing the study plan and schedule and the data collected, including an
explanation of any variance from the study plan and schedule.” (18 CFR 5.15(c)(1)) This Initial
Study Report (ISR) on Mercury Assessment and Potential for Bioaccumulation has been
prepared in accordance with FERC’s ILP regulations and details AEA’s status in implementing
the study, as set forth in the FERC-approved RSP as modified by FERC’s April 1 SPD and the
Quality Assurance Project Plan for Mercury Assessment and Potential for Bioaccumulation
Study for the Susitna-Watana Hydroelectric Project (QAPP) (collectively referred to herein as
the “Study Plan”).
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2. STUDY OBJECTIVES
Previous studies have documented increased mercury concentrations in fish and wildlife
following the flooding of terrestrial areas to create hydroelectric reservoirs. The purpose of this
study is to assess the potential for such an occurrence in the proposed Project area. The study
objectives as established in Study Plan (Section 5.7.1) are as follows:
• Summarize available and historic mercury information for the Susitna River basin,
including data collection from the 1980s Alaska Power Authority (APA) Susitna
Hydroelectric Project.
• Characterize the baseline mercury concentrations of the Susitna River and tributaries.
This will include collection and analyses of vegetation, soil, water, sediment pore water,
sediment, piscivorous birds and mammals, and fish tissue samples for mercury.
• Utilize available geologic information to determine if a mineralogical source of mercury
exists within the inundation area.
• Map mercury concentrations of soils and vegetation within the proposed inundation area.
This information will be used to develop maps of where mercury methylation may occur.
• Use the water quality model to predict where in the reservoir conditions (pH, dissolved
oxygen [DO], turnover) are likely to be conducive to MeHg formation.
• Use modeling to estimate MeHg concentrations in fish.
• Assess potential pathways for MeHg to migrate to the surrounding environment.
• Coordinate study results with other study areas, including fish, instream flow, and other
piscivorous bird and mammal studies.
3. STUDY AREA
As established in Study Plan Section 5.7.3, the study area begins at project river mile (PRM)
19.9 (RM 15.1) and extends upstream from the proposed reservoir to PRM 235.2 (RM 233.4)
(Figure 3-1).
4. METHODS AND VARIANCES IN 2013
4.1. Summary of Available Information
AEA implemented the methods as described for this section of the Study Plan with no variances.
Existing literature was reviewed to summarize the current understanding of the occurrence of
mercury in the environment. A recent and thorough literature review was conducted and
included in the Study Plan. Results of that review are provided again here as no additional
information is available. Sources included the following:
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• APA Susitna Hydroelectric Project
• Alaska Department of Environmental Conservation
• U.S. Geological Survey (Frenzel 2000)
• Western Airborne Contaminants Assessment Project
• Jewett and Duffy (2007)
• Geologic Data in ISR Section 4.5
4.2. Collection and Analyses of Soil, Vegetation, Water, Sediment,
Sediment Pore Water, Piscivorous Birds and Mammals, and
Fish Tissue Samples for Mercury
AEA implemented the methods as described in the Study Plan with the exception of variances
explained below. Mercury and other supporting analytes were collected from vegetation, soil,
surface water, sediment, sediment pore water, and fish tissue. (Table 4.2-1). The following
sections describe methods used to collect the various matrices and analytical methods to quantify
specific parameters (e.g., total mercury, dissolved mercury, methyl mercury, total organic
carbon, and sediment size).
4.2.1. Vegetation
AEA implemented the methods as described in this portion of the Study Plan with no variances.
A total of 50 vegetation samples were collected from various plants within the proposed
inundation zone in August 2013. Samples were collected from five sites in each of ten locations
within reservoir inundation zone. Figure 4.2-1 through 4.2-11 and Table 4.2-2.
The sampling was biased toward vegetative mass, that is to say species that were present in the
inundation area at low frequency and size were not be sampled, because even if these plants
contain mercury, their contributions to mercury methylation will be low. Only l eaves and
needles were collected. Samples were from several plant species, including trees and shrubs
(alder, willow, spruce, salmonberry) and herbaceous species (fireweed, bush cinquefoil).
Various types of vegetation at each individual sample site were aggregated into large Ziplock®
bags. The laboratory homogenized all plant species in each bag and analyzed each as a
composite sample. Plant samples were analyzed for total and methyl mercury per EPA Methods
1631 and 1630, respectively.
4.2.2. Soil
AEA implemented the methods as described in this portion of the Study Plan, with the exception
of the variances explained below (Section 4.2.2.1).
A total of 50 soil samples were collected at each of the vegetation sampling sites in the
inundation zone during August 2013 (Figure 4.2-1 and Table 4.2-2).
The soil samples were collected by advancing a hand dug test pit to the mineral soil. Samples
consisted of organic rich material found, including the moss, peat, and mineral soils. This
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material is most likely to contribute mercury to the proposed reservoir. Up to 20 g of soil were
placed into the appropriate laboratory provided sample container and sent for analyses. Samples
were analyzed for total mercury and MeHg using EPA Method 1631 and 1630, respectively, and
the results reported as both wet (ww) and dry (dw) weight.
4.2.2.1. Variances from the Study Plan
EPA Method 1631 recommends digestion of mineral soil with aqua regia and oxidized with
bromine monochloride (BrCl) to extract mercury from samples for analyses. The soil samples
collected in 2013 contained a significant fraction of peat and organic material mixed with soil.
For these types of organic soils, EPA recommends digestion with HNO3/H2SO4 digestion before
using BrCl. Given the soil was a mix of organic and inorganic components, the study team
elected to split each sample and analyze them using both digestion methods, giving two
analytical results for each sample. This change improved achievement of the study objectives by
making sure the maximum amount of mercury was extracted from the samples. No change to
the sample methods going forward will be necessary because the soil sampling is complete.
4.2.3. Water
AEA implemented the methods as described in this portion of the Study Plan, with the exception
of the variances explained below (Section 4.2.3.4).
There were two types of monitoring programs used to characterize mercury concentrations in
surface waters: Baseline Water Quality Monitoring (Study 5.5, RSP Section 5.5.4.4) and Focus
Area Monitoring (Study 5.5, RSP Section 5.5.4.5). These programs were distinguished by the
frequency of water sampling, the density of sampling effort in a localized area, and parameters
analyzed.
4.2.3.1. Baseline Sampling Protocols
For the baseline sampling protocols, water quality data collection occurred on average at 5 mile
intervals (Figure 3-1 and Table 4.2-3). Monthly samples were planned for collection from 17
locations from June 2013 to September 2013. An additional sampling location was added to this
monitoring effort at PRM 152.2 (Susitna River below Portage Creek) to make a total of 18
locations visited during 2013.
Grab samples were collected along a transect of the stream channel/water body, using methods
consistent with ADEC and EPA protocols and regulatory requirements for sampling ambient
water and trace metal water quality criteria. Mainstem areas of the river not immediately
influenced by a tributary were characterized with a single transect. Areas of the mainstem with
an upstream tributary that may influence the nearshore zone or that are well-mixed with the
mainstem were characterized by collecting samples at two transect locations: in the tributary and
in the mainstem upstream of the tributary confluence. Samples were collected at three equi-
distant locations along each transect (i.e. 25 percent from left bank, 50 percent from left bank,
and 75 percent from left bank). Samples were collected from a depth of 0.5 meters below the
surface as well as 0.5 meters above the bottom.
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Surface water grab samples were collected using one of two methods dependent upon field
conditions. Field personnel were equipped to perform either method and/or make modifications
based on site conditions, water velocity, and flow. Water quality sample containers were filled
using a high capacity peristaltic pump and non-reactive high density polyethylene (HDPE)
tubing system. The sample tubing was cable tied to a davit cable attached to a 50 to 75 lb.
weight and lowered into the water column. Once the tubing was positioned at the right depth the
pump was turned on and flushed for three minutes. Samples were collected from the tubing and
into the proper sample containers and labeled accordingly. Filtered samples (for dissolved
mercury) were collected after a 0.45 µm filter was attached to the tubing and flushed for one
minute. Some sample locations were located in water depths less than 3 ft. (<1 m) deep and
were not accessible by boat. In this case field personnel collected samples by wading into the
river, and using the HDPE tubing and peristaltic pump to collect the sample. The HDPE tubing
was secured to an extendable aluminum boat pole and placed along the bottom of the river such
that with the tubing opening was facing upstream at approximately mid-water column depth.
Water quality profiles at each location on each transect were also conducted for field water
quality parameters (e.g., temperature, pH, dissolved oxygen, and conductivity) to determine the
extent of vertical and lateral mixing.
All sample collection avoided pools and slack water. Sampling methods also avoided
unnecessary collection of sediments in water samples, and touching the inside or lip of the
sample container. Samples were delivered to a State-certified laboratory using EPA-approved
analytical methods including a separate completed chain of custody sheet. Field duplicates were
collected for 10 percent of samples (i.e., one for every 10 water grab samples, which includes
other water quality parameters collected for Study 5.5).
Grab samples were analyzed for a suite of parameters (see ISR Study 5.5); however, specific to
Study 5.7, samples were analyzed for total and dissolved mercury. Laboratory quality control
samples including duplicate, samples between laboratories, spiked, and blank samples were
prepared and processed by the laboratory.
4.2.3.2. Focus Area Sampling Protocols
The Focus Areas had a higher density of sampling locations, in contrast to the mainstem
network, so that prediction of change in water quality conditions from Project operations could
be made with a higher degree of resolution. The resolution expected for predicting conditions
were as short as 100-meter (m) longitudinal distances within the Focus Areas. Depending on the
length of the Focus Area, transects were spaced every 100 m to 500 m and water quality samples
collected at three or more locations along each transect. The collection locations along a transect
were in open water areas and had three to six collection points. These were discrete samples
taken at each collection point (Figure 4.2-12 and Table 4.2-4).
Grab samples collected from the Focus Areas were analyzed for a suite of parameters (see ISR
Study 5.5); however, specific to Study 5.7, samples were analyzed for total mercury and
methylmercury.
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4.2.3.3. Sample Handling and QA/QC
QA/QC samples included laboratory sample splits, field duplicates, matrix spikes, duplicate
matrix spikes, and rinsate blanks for non-dedicated field sampling equipment. The results of the
analyses were used in data validation to determine the quality, bias, and usability of the data
generated.
Sample numbers were recorded on field data sheets immediately after collection. Samples
intended for the laboratory were stored in a dedicated sample refrigerator and kept under the
custody of the field team at all times. Samples were transported to the laboratory in coolers with
ice the following day by a member of the field team. Chain of custody records and other
sampling documentation were kept in sealed plastic bags (Ziploc®) and taped inside the lid of the
coolers prior to transport. A temperature blank accompanied each cooler. Packaging, marking,
labeling, and shipping of samples was in compliance with all regulations promulgated by the
U.S. Department of Transportation in the Code of Federal Regulations, 49 CFR 171-177.
Water quality samples were labeled with the date and time that the sample was collected and
filtered/preserved (as appropriate), then stored and delivered to a State-certified water quality
laboratory (laboratory) for analyses using EPA-approved methods in accordance with maximum
holding periods. A chain of custody record was maintained with the samples at all times.
The laboratory reported data electronically (Excel, Access database, PDF) results for each
chemical parameter analyzed with the laboratory method detection limit, reporting limit, and
practical quantification limit. The laboratory attained method detection limits specified in the
QAPP that were at the applicable regulatory criteria and provided all laboratory QA/QC
documentation. However, the method detection limit should be lower for estimating total
phosphorus concentrations (MDL ≤ 2.0 µg/L) than was achieved for analysis of surface water
samples collected during 2013.
The procedures used for collection of water quality samples followed protocols from ADEC and
EPA Region 10 (Pacific Northwest).
Additional details of the sampling methods are provided in a combined SAP and the QAPP for
this study.
Water samples were analyzed for mercury (total and dissolved) and methylmercury utilizing
EPA Methods 1631E and 1630.
4.2.3.4. Variances from the Study Plan
Table 5.7-5 in Study 5.7, RSP Section 5.7.4.2.3 indicated that water samples would be collected
for mercury analysis at PRM 225.5 (Susitna near Cantwell). Due to limited site access by
helicopter, the site was relocated to PRM 235.2 (Susitna River adjacent to Oshetna Creek). This
change is not expected to interfere with the study objectives as concentrations of mercury are not
expected to change appreciably between the two areas. No further information needs to be
generated with future monitoring from this new site location. One site had minor modifications
to the specific monitoring location at least once during the field season due to helicopter
accessibility; however, these sites were not appreciably different from those identified in the
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Study Plan. During the 2013 field effort, monitoring was required at PRM 225.5 for water
quality samples. The collection effort differed from the original monitoring plan by relocating
this site from PRM 225.5 (Susitna near Cantwell) to PRM 235.2 (Susitna River adjacent to
Oshetna Creek) due to limited site access by helicopter.. The close proximity to the proposed
sites in the Study Plan will not result in any effect on study objectives. There are no known
influences to water quality between the proposed monitoring sites and those that were sampled.
Study 5.5, RSP Section 5.5.4.4.2 indicated that samples would be collected at three locations
along each transect for mainstem samples. Water samples from PRM 235.2 (Susitna River
adjacent to Oshetna Creek) and 187.2 (Susitna at Watana Dam) were collected from just one
position in the river due to limited access when wading.
4.2.4. Sediment and Sediment Porewater
AEA implemented the methods as described in this portion of the Study Plan, with the exception
of the variances explained below (Section 4.2.4.1).
Sediment and sediment porewater samples were collected in the mainstem Susitna River near the
mouths of the following tributaries: Jay, Kosina, and Goose creeks, and the Oshetna River.
Samples were collected downstream of islands, and in similar riverine locations in which water
velocity was slowed, favoring accumulation of finer sediment along the channel bottom. A map
of the sediment/porewater sampling locations is shown in Figure 4.2-13. Images of each
sampling location can be seen in Figures 4.2-14 and 4.2-15.
Sediment samples were collected using a hand auger or stainless steel spoon. Two field staff
collected samples; one handling sampling equipment (dirty hands) while the other received the
sediment sample in collection jars and prepared labeling (clean hands). All sediment samples
were collected by wading into shallow nearshore areas of each tributary site. Sampling collected
from the top 6 inches (15 cm) of sediment. All the sediment samples were photographed. At all
locations the sample jar was not overfilled, the sediment was covered by water, and at least the
top two inches of sediment was collected. Mercury occurrence is typically associated with fine
sediments, rather than with coarse-grained sandy sediment or rocky substrates. Therefore, the
sampling obtained sediments with at least 5 percent fines (i.e., particle size <63 μm, or passing
through a #230 sieve).
Sediment porewater was collected from the sites listed above and separated from sediments in
the field laboratory using a pump apparatus to draw porewater from each of the replicate
samples. Filtering of samples utilized a 0.45-µm pore size filter in both the lab apparatus and
field apparatus.
Samples were analyzed for total mercury by EPA Method 1631E. In addition, sediment size and
total organic carbon (TOC) were also analyzed to evaluate whether these parameters are
predictors for elevated mercury concentrations.
4.2.4.1. Variances from the Study Plan
The Study Plan RSP Section 5.7.4.2.4 indicated that sediment and sediment porewater samples
would be collected from just above and below the proposed dam site, including Fog, Tsusena,
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Deadman, Watana, Kosina, Jay, and Goose Creeks, and the Oshetna River. Due to lack of access
to CIRWG lands in 2013, samples were not collected from the Susitna River just below and
above the proposed dam site, and the mouths of Fog, Deadman, Watana, and Tsusena Creeks.
Sediment sampling at these sites is planned for the next year of study. If site access is not
possible, alternate sites will be selected. It is not expected that changing the sample locations
will affect achievement of the study goals.
The Study Plan Attachment 5-1 indicated that the samples would be collected from a boat using
an Ekman dredge or a modified Van Veen grab sampler. This was modified in the QAPP to
include possible collection of samples by wading in shallow nearshore areas and using either a
hand auger or stainless steel spoon to collect samples. During the 2013 field work, it was found
that collection of sediment samples from a boat was impractical in the upper river. The choice of
sample collection method should not impact analytical results, and the sampling method used is
expected to achieve the study objectives. This change will be implemented for the remaining
sediment sampling in 2014 (See Section 7.1.1).
4.2.5. Piscivorous Birds and Mammals
AEA implemented the methods as described in this portion of the Study Plan, with the exception
of the variances described in Section 4.2.5.1.
Per the Study Plan, feathers piscivorous birds were sought during the wildlife bird surveys
(Study 10.15). When nests of obligate piscivorous waterbirds (e.g., loons, grebes, terns) were
observed during the breeding aerial surveys, the locations were recorded as GPS waypoints and
marked on field survey maps. The locations of broods of piscivorous waterbirds also were
recorded during brood and fall migration surveys. The results of the species identification are
presented in Study Section 10.15.
Only one Common Loon nest was found in the inundation zone and no nests of other piscivorous
waterbirds were found in 2013. Lack of access to CIRWG lands prevented a visit to look for
feather samples at the Common Loon nest. Broods of all piscivorous waterbirds were found in
the waterbird study area and nearby lakes. These nests can be targeted during future surveys for
nesting birds.
The opportunistic collection of feathers from any Belted Kingfisher nests located during the
landbird and shorebird field surveys was proposed for transfer to the mercury study lead for
laboratory analysis of methyl-mercury levels. No Belted Kingfisher feathers were collected in
2013, however, because no nests of that species were found during the field surveys.
Feather samples were not obtained from piscivorous raptors for mercury analysis in 2013 (Study
10.14, RSP Section 10.14.4.1). Osprey nests were not documented in the study area and the
necessary federal permit for salvage of Bald Eagle feathers could not be obtained in time before
the season ended.
Fur samples from river otters and mink from animals harvested by trappers in the study area was
attempted but was unsuccessful. Based on a review of ADF&G records it does not appear that
there have been appreciable harvests of mink or river otter in this area for the last several years.
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In addition, state regulations prevent identification of trappers and harvest locations using
ADF&G data.
4.2.5.1. Variances from the Study Plan
The Study Plan required feathers to be collected from nests of raptors (principally bald eagles),
loons, grebes, arctic terns, and kingfishers found during the wildlife surveys in 2013. No feather
samples were collected for MeHg analysis in 2013. As described above, feather samples were
either not available for collection, or as for Bald Eagles, were not obtained for mercury analysis
in 2013 (Study 10.14, RSP Section 10.14.4.1) because the necessary federal permit for salvage of
Bald Eagle feathers could not be obtained in time before the season ended. Hence, collection of
Bald Eagle feathers has been postponed until the nesting season of the next year of study, by
which time the eagle salvage permit is expected to be issued. Alternate methods for collecting
samples from other piscivorous birds will need to be considered.
It was anticipated that obtaining fur samples could be problematic due to the low level of
trapping in the area. No fur samples were collected for MeHg analysis in 2013. Alternate
methods for collecting fur samples from piscivorous mammals will need to be considered. These
may include targeted trapping or expansion of the proposed study area.
4.2.6. Fish Tissue
AEA implemented the methods as described in this portion of the study plan, with the exception
of the variances explained below (Section 4.2.6.1).
Target fish species in the vicinity of the Susitna-Watana Reservoir were Dolly Varden, Arctic
grayling, stickleback, longnose sucker, whitefish species, lake trout, burbot, and resident rainbow
trout. Sample locations are shown on Figure 4.2-16. When possible, seven individuals from
each species were collected, and larger, adult fish were specifically targeted. Given that MeHg
accumulates primarily in the muscle tissue, fillets were analyzed. Collection times for fish
samples occurred in August through October.
Samples were analyzed for total mercury and MeHg by EPA Methods 1631 and 1630,
respectively. Liver samples were also collected from burbot and analyzed for total mercury and
MeHg.
Field procedures were consistent with those outlined in applicable ADEC and/or EPA sampling
protocols (USEPA 2000). Clean nylon nets and polyethylene gloves were used during fish tissue
collection. Species identification, measurement of total length (mm), and weight (g) were
recorded, along with sex and sexual maturity when possible (see variances). When possible,
efforts were made to determine the age of the fish, including an examination of otoliths or
comparisons with established age/length curves for the Susitna River (APA 1984).
4.2.6.1. Variances from the Study Plan
Study Plan RSP Section 5.7.4.6.1 proposed to collect seven to ten fish of each target species.
However, additional fish were collected for Arctic grayling (16) and round whitefish (12).
Multiple field teams were working at the same time, and a full count of all the fish captured
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could not occur until the field teams returned to camp. This additional sampling should improve
achievement of the study objectives. No change is required in 2014, since no additional
specimens of these fish will be captured and analyzed.
The Study Plan required that only adult fish of each species be captured and analyzed. Some
juvenile Arctic grayling and whitefish were captured incidentally. While most were released, if a
juvenile fish was captured accidentally and died, it was analyzed. This change should enhance
achievement of the study objectives since the minimum number (7) of adult fish for each species
was captured and analyzed, and this additional data allows for a better evaluation of mercury
accumulation rates in target species. No change is required in 2014, since no additional
specimens of these fish will be captured and analyzed.
The Study Plan required capture and analyses of a minimum of seven specimens of humpback
whitefish. However, only one humpback whitefish was captured after several weeks of effort.
These fish appear to be very rare in the study area. The lack of this species in the study area
should not impact the study objectives since sufficient round whitefish were captured in the area,
and there should be little variation in the feeding habits or mercury accumulation rates between
these two species. No change is required in the next year of study, since no additional specimens
of these fish will be captured and analyzed.
The Study Plan required that all fish be speciated, however, two whitefish were captured that
could not be speciated. The differences between round whitefish and humpback whitefish are
generally small. Based on the frequency of the capture of round whitefish in the study area, it
appears likely these were also round whitefish. More than sufficient numbers of round whitefish
were collected to complete this study. No change is required in the next study year, since no
additional specimens of these fish will be captured and analyzed.
The Study Plan called for capture and analyses of rainbow trout or sticklebacks, however, there
is no evidence that either of these species reside in the inundation zone. The lack of capture for
these species should not impact the study, since these fish do not appear to be present in the
inundation zone. No change is required in the next study year, since no specimens of these fish
will be captured and analyzed.
Capture and analysis of slimy sculpin was not included in the Study Plan; however, they were
found to be present in large numbers in the study area, and were therefore sampled. This
sampling effort should enhance the achievement of the study objectives, by adding additional
data on mercury for this species. Whole body samples were analyzed due to their small size. No
change is required in the next year of study, since no additional specimens of these fish will be
captured and analyzed.
Initially, extraction of the otoliths was to occur in the field if possible; however, field conditions
were not conducive to this work. To date, 21 fish have had otoliths extracted and analyzed for
age as part of this study. Some of the fish, such as slimy sculpin and juvenile specimens, were
simply too small to successfully extract otoliths. This change should not impact achievement of
the study goals.
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The Study Plan required determination of the sex and sexual maturity of the fish, however,
determination of gender for the fish proved to be problematic in the field, and the sex of only 12
fish was determined. This was because the gender of most fish could not be easily determined
through visual examination, and dissecting the fish in the field introduced the potential for cross
contamination of tissue samples. The gender of some fish was determined at the analytical
laboratory; however, the laboratory was inconsistent with implementing gender identification.
This change is not anticipated effect achievement of the study objectives, since Jewett and Duffy
(2007) have shown that sex is not a determining factor in the mercury concentration in fish
across several species.
The Study Plan indicated that fish samples would be collected from August to September;
however, the sample period was extended into early October to obtain sufficient sample size for
targeted species. Bodaly et al (1993) showed that mercury concentrations in fish, when
controlled for age and reservoir size, were strongly related to shallow water temperatures. There
is little change in shallow water temperature in the Susitna between September and early
October. In addition, the alternative was to collect insufficient fish samples to complete the
study. No change is required in the next year of study, since additional fish sampling will be
limited.
The project QAPP stated that Teflon sheets would be used for the fish when placed in the sample
bag. The study team had difficulty sourcing this material, and switched to polyethylene sheets.
Given that muscle samples are taken from inside the fish, this material should not have
introduced any contamination to the sample and have no effect on achievement of the study
objectives. The study plan will be modified to allow use of polyethylene sheets for sampling.
5. RESULTS
5.1. Summary of Available Information
The following sections are a summary of the available mercury information for the Susitna River
basin, including data collection from the 1980s APA Susitna Hydroelectric Project, and existing
geologic information to determine if a mineralogical source of mercury exists within the
inundation area.
5.1.1. APA Susitna Hydroelectric Project/USGS
Limited mercury sampling was performed during efforts to develop hydropower resources on the
Susitna River in the 1980s (Alaska Power Authority 1984). This data was summarized in the
data gap analyses report prepared for the project (URS 2011) and is currently available on-line
from the U.S. Geological Survey (USGS): http://www.usgs.gov/water.
Water and sediment samples were collected from Gold Creek (PRM 140.1), Susitna at Parks
Highway East (PRM 87.8), and Susitna Station (PRM 29.9) (Table 5.1-1 to Table 5.1-3).
Sampling occurred within the period from January 20, 1975 to June 16, 2013; however, a
majority of the samples were collected prior to 1986. The following conclusions can be drawn
from this limited data set:
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• Most of the water samples were not found to contain detectable concentrations of
mercury; however, the older samples had higher detection limits (0.1 µg/L) than current
methods, and concentrations of mercury in natural waters would be expected to routinely
fall below this limit;
• Many of the detections appeared to occur at or very near the detection limit for the
analyses. Such detections are often suspect, given they are close to the theoretical
maximum sensitivity of the equipment;
• More modern analyses by the USGS (2012-2013), with lower detection limits, suggest
that mercury concentrations in the water range from 0.008 to 0.035 µg/L in unfiltered
samples, and is undetectable in filtered samples, suggesting that the majority of the
mercury detected is associated with suspended sediment.
• The data from the U.S. Geological Survey (USGS) National Water Information System
(NWIS) Web database may include data that is provisional and subject to revision.
5.1.2. Alaska Department of Environmental Conservation
ADEC has been analyzing fish samples in Alaska since 2001 for trace metals (total mercury,
selenium, copper, lead, and cadmium) to determine if Alaska fishes are being negatively
impacted by environmental pollutants (ADEC 2012). The results are summarized in Table 5.1-4.
As expected, concentrations of mercury in piscivorous species such as lake trout and burbot are
much higher than concentrations in non-piscivorous species such as grayling and whitefish.
Nearly every fish analyzed from Alaska by ADEC has been found to have some mercury present.
ADEC has provided AEA with an additional detailed breakdown of data regarding the number,
location, and species of fish collected on the Susitna River Basin. These sample locations are
shown on Figure 5.1-1, and the analytical data is shown on Table 5.1-5.
It should be noted that the data presented in this study may be biased high. In many cases the
fish selected for analyses by ADEC are collected from locations where mercury accumulation in
fish tissues is suspected to be a problem. It should also be noted that the analysis, while believed
to be accurate, is not being performed utilizing standard EPA approved QA/QC methods, and
should be considered as screening level data only.
5.1.3. USGS (Frenzel 2000)
The purpose of this study was to document the occurrence of organochlorines, SVOCs, and trace
elements (including mercury) in streambed sediments and fish tissues at 15 sites in the Cook
Inlet Basin in southcentral Alaska. Fish tissue (whole body slimy sculpin) was collected from 12
sites, and mercury in sediment was analyzed from 14 sites (Figure 5.1-2). About half of the sites
were located along the road system, but seven sites were located in more remote areas including
three national parks. Four of the sites were located on water bodies hydrologically connected to
the Susitna River.
The sediment results showed mercury concentrations ranged from 30 ng/g dw in the Kenai River
near Soldotna, to as high as 460 ng/g in the Deshka River (Table 5.1-6). Many of the mercury
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concentrations significantly exceeded the national average of 60 ng/g, and the concentration of
mercury in sediments appeared to be correlated with the acres of wetlands associated with each
drainage. MeHg has been shown to be positively influenced by wetlands density in other studies
(St. Louis et al. 1994).
Mercury concentrations at the Denali National Park (DNP) sites were higher than those typically
observed in national parks (Gilliom et al. 1998), but did not exceed the background
concentrations found in other areas examined in Alaska. Colorado and Costello Creeks appear to
drain a part of DNP that is highly mineralized and the USGS believed that this contributed
mercury to streambed sediments.
Partitioning of inorganic mercury and MeHg in unsieved streambed sediment, fish tissue, and
water was examined in a variety of environmental settings. Five sites were sampled in the Cook
Inlet Basin (Table 5.1-7). The Deshka River, having a greater density of wetlands, was also
found to have a much higher concentration of MeHg than other sites.
5.1.4. Western Airborne Contaminants Assessment Project
The Western Airborne Contaminants Assessment Project (WACAP) was initiated to determine
the risk from airborne contaminants (including mercury) to ecosystems and food webs in western
national parks of the United States (Landers et al. 2008). From 2002 through 2007, WACAP
researchers conducted analysis of the concentrations and biological effects of airborne
contaminants in air, snow, water, sediments, lichens, conifer needles, and fish in watersheds in
each of eight core parks in the western United States. In Alaska these parks included Noatak
National Preserve (NOAT), Gates of the Arctic National Park (GAAR), and DNP.
5.1.4.1. Atmospheric Deposition of Mercury
The WACAP project collected numerous air, snow, and precipitation samples from the Wonder
Lake area of DNP to analyze precipitation of mercury. This lake is approximately 60 miles from
the proposed reservoir.
Much of the mercury found in the snow at Wonder Lake was associated with particulate carbon,
and found at higher concentrations in snow samples from forested sites compared with samples
from open meadows. It is possible that the mercury and particulate carbon become associated in
the atmosphere and are deposited to the snowpack together. Or they could be deposited
separately and become associated within the snowpack. Either way, it was theorized that
particulate carbon might act to sequester more of the deposited mercury, increasing the net flux
of mercury to the watershed when the snowpack melts. The deposition flux of mercury was
336 ng/m2/yr at Wonder Lake.
5.1.4.2. Vegetation
Samples were collected at multiple sites in GAAR, NOAT, and DNP for lichen (Masonhalea
richardsonii and Flavocetraria cucullata). The mean concentration of mercury in the vegetation
ranged from 12 ng/g ww for DNP to 26 ng/g dw at GAAR (Table 5.1-8).
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5.1.4.3. Fish
At NOAT and GAAR fish samples were collected from Burial and Matcharak Lakes,
respectively. These lakes have small watersheds, contributing to long hydraulic residence times.
Mercury concentrations exceeded thresholds for wildlife health, and the median mercury
concentration in Burial Lake and in some fish in Matcharak lake exceeded the human
contaminant health threshold of 300 ng/g (Table 5.1-9).
Samples of burbot collected from McLeod Lake in DNP were found to have median
concentration of mercury (58.34 ng/g), and lake trout from Wonder Lake DNP were found to
have median concentrations of mercury of 112.59 ng/g (Table 5.1-9).
5.1.5. Jewett and Duffy (2007)
Jewett and Duffy (2007) provided a summary of the occurrence and distribution of mercury in
fish within Alaska, and while it is not directly related to the proposed study area, it summaries
the previous 22 years of studies in the state and provides some insights regarding the occurrence
and nature of mercury in Alaskan fish.
The study included data from 17 freshwater fish species (n=775) from Alaska, including juvenile
salmon. Much of this data was collected from national wildlife refuges and other otherwise
pristine areas. Tissues of the piscivorous northern pike had total mercury concentrations that
typically exceeded USEPA and ADEC tissue-based water quality criterion relative to
consumption of fish by humans (300 ng/g) and U.S. Food and Drug Administration (USFDA)
action level for human consumption (1,000 ng/g). For example, 44 percent of the pike examined
from the Nowitna National Wildlife Refuge in 1987 had concentrations in tissues between 1,000
and 2,900 ng/g (Snyder-Conn et al. 1993). A study on subsistence fishes in the Yukon-
Kuskokwim Delta area reported 36 percent of the pike examined had total mercury in muscle
tissue that exceeded the 1,000 ng/g (Duffy et al. 1999).
Significant regional differences were observed in mercury concentrations. For example, fish
from parts of the Yukon were found to have mercury concentrations 2 to 3 times higher than
concentrations in the same species from the Kuskokwim River. Overall mercury concentrations
in fish were found to be highly variable among collection locations, fluctuating nearly an order
of magnitude.
As with other similar studies, Jewett and Duffy found mercury concentrations in fish tended to
increase with age, and therefore with the fish size as well (Johnels et al. 1967; Jewett et al. 2003).
While age is the preferred parameter of comparison, fish length or body weight can be used for
approximation of age (Jewett et al. 2003; Zhang et al. 2001). In general, there was no difference
reported in mercury concentrations between sexes of similar sized fish.
5.1.6. Geologic Data
A geologic study is being performed to evaluate the surficial and bedrock geology, geologic
structure, mass wasting, and mineral resources in the study area (Study 4.5). Of particular
interest to this study is the identification of potential geologic sources for mercury to the
reservoir. The survey included identifying mining claims and prospects in the Project area from
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data sources (e.g., State of Alaska mining claim website); field reconnaissance of selected areas
of high mineral potential, mineral licks, and mining claims; and consultations with active miners
and geologists familiar with the area (USGS, BLM, Alaska Earth Sciences, CIRI, and
claimholders). Additionally, several rock samples were collected and chemically analyzed for a
wide range of potentially economic minerals.
In summary, no mining claims appear to be present within the inundation zone of the reservoir.
Exposed rock types identified within the inundation zone consist of gneissose granitic rocks,
granodiorite, quartz monzonite, amphibolite, argillite, chert, sandstone, and limestone, and other
undifferentiated sedimentary rocks. The mineral resources assessment (ISR 4.5) also included
the identification and review of potential sources of acid rock drainage (ARD) and mineral licks.
Only four such locations were identified in the area, none of which are within the inundation
zone.
Based on the information developed to date, there does not appear to be a significant
mineralogical source of mercury or sulfate minerals in the inundation zone for the reservoir.
Additional geologic mapping and sampling is planned for the next year of study (Study 4.5) and
the results of this field work will be reviewed for relevance to this study area.
5.2. Vegetation
The vegetation found at each of the sample sites is shown on Table 5.2-1. In summary, 50
vegetation samples were collected from 10 separate locations within the inundation zone. Only
the dominant plant species were sampled at each location. Overall, the vegetation found at each
of the sample location was limited in species and volume. Plants were generally found to be in
one of four categories:
• Plants common to many sample sites, with a large vegetative mass (alder, willow, bog
blueberry, and low bush cranberry).
• Plants present at just a few sample sites, but at large vegetative mass when present
(salmonberry, prickly rose, etc.).
• Plants common at many sample sites, but with low vegetative mass (bog birch, horsetail,
etc.).
• Rare plants present in small numbers (fireweed, soapberry, etc.).
Only the first two categories of plants were sampled.
The analytical results of the vegetation analyses were received from the contract laboratory too
late for inclusion in this ISR and will therefore be provided after QA/QC of the data is
completed.
5.3. Soil
All of the planned soil sampling was completed. The soil samples each consisted of a
combination of surface moss, peat, and mineral soil (Table 5.3-1). At each sample location there
was a significant fraction of organic material (moss and peat) above the mineral soil. This
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material is the primary potential source or mercury methylation in the reservoir after
impoundment.
The results of the soil analyses were received from the contract laboratory too late for inclusion
in this ISR and will therefore be provided after QA/QC of the data is completed.
5.4. Water
The results of water quality mercury analyses are provisional, and are not included in the Water
Quality ISR Study 5.5.
5.5. Sediment and Sediment Porewater
Sediment samples were collected at four of the ten proposed sample locations at mouths of the
following tributaries: Jay, Kosina, and Goose creeks, and the Oshetna River (Figure 4-2.13).
The remaining samples will be collected in the next year of study. The collected samples were
analyzed for the parameters shown in Table 4.2-1. Sufficient fine grained material was found at
each of these sample locations to meet the study objectives listed in Section 4.2.4.
The results of sediment and sediment porewater mercury analyses were received from the
contract laboratory too late for inclusion in this ISR and will therefore be provided after QA/QC
of the data is completed.
5.6. Piscivorous Birds and Mammals
The Study 10.16 study team completed a scientific literature review on the foraging habits and
diets of piscivorous landbirds and shorebirds (primarily Belted Kingfisher, but also American
Dipper and Spotted Sandpiper) (see ISR Study 10.16) to inform the mercury risk-assessment
study (Study 5.7) and to complement the field data gathered on the distribution and abundance of
these species in the study area. The literature review focused on studies conducted in Alaska to
the extent possible, but few such studies were available, so literature from elsewhere was
included. This literature review will be considered by the mercury risk-assessment study team in
2014.
Piscivorous species where fish are likely to compose 40 percent or more of the diets observed in
the reservoir area included Common Loon, Merganser, Red-throated Loon, Red-necked Grebes,
Bonaparte’s Gulls, and Arctic Terns. Several broods of these species were observed. Only a
single Common Loon nest were found during the waterbird aerial surveys in 2013 (those surveys
focused on locating adult birds and broods, rather than nests). One Common Loon nest was
found in the Watana Reservoir survey area, but could not be visited because it was located on
CIRWG lands. Locations where broods, but not nests, were found in 2013 can visited in the next
year of study to look for nests. Plans for sampling nests of piscivorous waterbirds will be
discussed further with the TWG.
The study teams were not able to obtain any feather samples of piscivorous raptors for mercury
analysis in 2013 because no Osprey nests were found in the study area and the necessary federal
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permit for salvage of Bald Eagle feathers could not be obtained in time before the season ended.
Sampling of Bald Eagle feathers will be pursued during the next year of study.
Fur samples from river otters and mink were sought from animals harvested by trappers in the
study area in 2013. However, state regulations prevent identification of trappers and harvest
locations using ADF&G data. Therefore the alternate method of placing hair snag “traps” will
be utilized in the next year of study (Study 10.11).
5.7. Fish Tissue
The results of fish tissue mercury analyses were received from the contract laboratory too late for
inclusion in this ISR and will be provided after QA/QC of the data is completed. To date, 21
otoliths have been extracted and are being analyzed for age as part of this study. Extensive data
from the 1980s studies exists on the relationship between fish size and age in the Susitna River.
Figures developed as part of previous studies are provided in Figure 5.7-1 through Figure 5.7-4.
The following sections discuss the available data on a species by species basis.
5.7.1. Lake Trout
Two lake trout were collected in 2012 from Sally Lake (Figure 4.2-16). This lake was not
accessible this year, however, Cushman Lake and Deadman Lake were accessible, and would be
hydrologically connected to the proposed reservoir after filling. Seven lake trout were captured
from Deadman Lake in 2013. Otoliths were extracted from all seven of these fish. The otolith
data is still being analyzed. While lake trout were present in Cushman Lake, none were caught
during the study period.
Previous studies of lake trout from various lakes in the Susitna drainage and in Deadman Lake
(Burr 1987) found there to be a good relationship between fish fork length and age (Figure
5.7-1). It should be noted that unlike other fish, the relationship between lake trout length to age
may be lake specific, and even small changes in lake conditions can impact growth significantly
(Burr 1987). Based on that relationship and the data collected in this study the fish captured for
this study ranged from 6 to 26 years old. This data will be confirmed when the analyses of the
otoliths collected from these fish is complete.
5.7.2. Longnose Sucker
A total of seven longnose suckers (LNS) were captured from the river (Figure 4.2-16). Five of
these fish were captured at the confluence of the Susitna and Oshetna Rivers, the remainder in
the mainstem Upper Susitna River. The fish ranged in size from 315 to 430 mm, and in weight
from 303 to 500 g. Otoliths were successfully extracted from 5 of these fish.
Previous studies of the LNS in the Susitna Middle River (APA 1984) found there to be a good
relationship between fish fork length and age (Figure 5.7-2). Based on that relationship and the
data collected in this study, the fish captured ranged from seven to over 13 years old. This data
will be confirmed when analyses of the otoliths collected as part of this study are complete.
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5.7.3. Dolly Varden
Dolly Varden were found to be rare in the inundation zone, with the only area of their occurrence
being the upper Watana Creek (Figure 4.2-16). A total of seven fish were captured from this
location. The fish ranged in size from 177 mm to 204 mm, and in weight from 47 g to 70 g.
Otoliths were successfully extracted from four of the fish as part of this study. Twenty-eight
additional otoliths were extracted as part of the Study of Fish Distribution and Abundance Study
(9.5).
5.7.4. Arctic Grayling
A total of 16 Arctic grayling were captured as part of this study. Most were captured from
Kosina Creek, where the species appears to be plentiful (Figure 4.2-16). The fish ranged in size
from 75 mm to 340 mm, and in weight from 12 g and 385 g. Two fish were also captured in
2012 from Watana Creek, and one was captured from the Oshetna River. Some of the fish
captured appeared to be juveniles (<2 years old), however, the field crews were directed to keep
any fish accidentally killed during other studies for inclusion in this study. No otoliths were
successfully extracted from Arctic grayling.
Previous studies of the Arctic grayling in the Upper Susitna River (APA 1984) found there to be
a good relationship between fish fork length and age (Figure 5.7-3). Using this data, it would
appear that the fish captured in 2013 ranged from 0.5 to over 8 years old.
5.7.5. Burbot
A total of eight burbot were collected from the mainstem of the Upper Susitna River in the
inundation zone, two were captured in 2012, and six in 2013 (Figure 4.2-16). The fish ranged
narrowly in size from 390 mm to 467 mm, and in weight from 312 g to 553 g. Two otoliths were
successfully extracted from the burbot. For the fish collected in 2013, burbot livers were also
analyzed for mercury and other metals.
5.7.6. Slimy Sculpin
A total of seven slimy sculpin were collected from the mainstem of the Upper Susitna River in
the inundation zone in 2013 (Figure 4.2-16). Unlike the other species studied here, the analytical
results of the slimy sculpin were evaluated for whole fish. The fish ranged narrowly in size from
74 mm to 100 mm, and in weight from 3.6 g to 6.6 g. The fish were not aged due to their small
size.
5.7.7. Whitefish
Humpback whitefish were found to be rare in the inundation zone. Only a single fish was
positively identified; however, two other unidentified whitefish were also captured. The
remaining 10 whitefish captured appeared to be round whitefish. The fish were captured
throughout the proposed inundation zone. Otoliths were extracted from three of the fish for
analyses.
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Three of the whitefish captured appeared to be juveniles, but were analyzed since they had been
accidentally killed in rotary screw traps. Including the juveniles, the fish ranged in size from 140
to 450 mm, and in weight from 57.1 to 470 g.
Previous studies of the round whitefish in the Susitna Middle River (APA 1984) found there to
be a good relationship between fork length and age (Figure 5.7-4). Based on the data collected
in this study the fish captured for this study ranged from 1 to 20 years. This data will be
confirmed when the otoliths collected as part of this study are analyzed. It should be noted that
the Middle River is more productive than the Upper River, meaning the same size fish may be
younger in the Middle River than the Upper River because there is more food available.
Therefore using age data from the Middle River could underestimate age for Upper River fish.
6. DISCUSSION
6.1. Current Status of the Study Effort
Most of the necessary data for completion of the study objectives was collected in 2012 and
2013. The following sections summarize the status of the various elements of the study and the
findings thus far. Because the laboratory data is still being reviewed, the discussion of this data
will be limited.
6.1.1. Summary of Available Information
The summary of the available information has been completed and is presented in this document.
If additional data becomes available it will be incorporated. The geologic data is still being
reviewed as part of Study 4.5; any additional findings from that study will be incorporated as it
becomes available.
6.1.2. Vegetation and Soil
The proposed data collection goals have been met. The adequacy of data collection in 2013 to
meet the study objectives will be confirmed following completion of data QA/QC.
There is no data from the previous studies of the dam site in the 1980s on mercury
concentrations in vegetation and soils. Understanding the impact of these sources of mercury on
reservoirs was just beginning at that time.
The vegetation types at the site do not appear to be variable within the inundation zone, with
only three to four species representing the majority of the vegetation mass. However, there was
a considerable mass of organic material (moss and peat) at almost all the sample locations.
Where soils have developed on uniform parent material vegetation, cover type and cover age are
reported to be very important variables affecting concentration of mercury in soils (Grigal et al.
1994). This is certainly true in the Friedli et al. (2007) study (Table 6.1-1) of an upland boreal
forest in the Prince Albert National Park, Saskatchewan, Canada. They found that 93 to 97
percent of the mercury resided in the organic soil above the mineral layer. The mercury input to
the ecosystem is from wet and dry deposition to the land surface and is trapped in the organic
soil layers. They also found that periodic forest fires can “reset” the mercury concentration to a
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lower level, and that mercury concentrations increase slowly in the soil over time. It is expected
that the predominate source of mercury to the newly formed reservoir will be from this source,
rather than from the vegetation.
6.1.3. Water
While mercury samples were collected during studies conducted in the 1980s, it appears that the
analytical methods utilized at the time were of insufficient sensitivity to detect mercury
concentrations in the water (>0.1 µg/L). The few detections found were at or very near the
detection limit for the analytical method. Such detections are often suspect, given they are close
to the theoretical maximum sensitivity of the equipment. Modern analyses by the USGS (2012-
2013), with lower detection limits, suggest that mercury concentrations in the water range from
0.008 to 0.035 µg/L in unfiltered samples, and is undetectable in filtered samples, suggesting that
the majority of the mercury detected is associated with suspended sediment.
6.1.4. Sediment and Sediment Porewater
Only a limited amount of sediment and sediment porewater data has been collected from the
study area (four of the ten sample locations). Previous studies generally focused on suspended
sediment, and suffered from the same elevated detection limits as the water sampling from that
period, as discussed above.
6.1.5. Piscivorous Birds and Mammals
Efforts to collect bird specimens have so far been unsuccessful. This potential problem was
identified in the Study Plan and discussed with the TWG, in that it is difficult to collect non-
lethal samples for animals with very low population densities in rugged terrain. Piscivorous
birds have been identified in the area at low numbers; however only one nest was located during
the 2013 wildlife surveys. Lack of access to CIRWG lands and a Bald Eagle collection permit
further limited the potential for sample collection.
Based on the previously described issues, it is difficult at this time to fully evaluate the potential
for success of the proposed feather sampling strategy in the next year of study. Potential
alternative methods will be developed and discussed with the TWG. These may include:
• Peregrine falcons are predators of a variety of birds, including waterbirds. Feathers of
prey could be collected from Peregrine falcon nests in the study area.
• Expansion of the study area to include nearby areas with larger populations of
piscivorous birds.
• Revisiting areas where broods of piscivorous birds were observed, but nests not
identified.
• Gaining access to CIRWG lands and obtaining a Bald Eagle collection permit.
The success of proposed winter fur snagging surveys potentially to be conducted during the next
year of study is unknown, based on the low population of river otters and mink in the study area.
Snagging fur, particularly for small mammals, works best when population density is high,
providing more opportunities for success. Depending on the success of collecting adequate
samples, alternative methods may be considered.
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Absent samples from aquatic mammals from the inundation zone, it might be necessary to
expand the collection area to the Middle River. However, this may not be suitable, in that
mercury concentrations may be specific to the area where the mammal is feeding, and the farther
from the proposed inundation zone the sampling occurs, the less representative it may be of
localized conditions.
6.1.6. Fish Tissue
MeHg can be detected in nearly every fish analyzed in Alaska, which is consistent with the
primary source of mercury to most aquatic ecosystems being deposition from the atmosphere.
Studies around the state provide comparisons of background mercury concentrations for fish
collected from the study area. When the results of the fish tissue analyses from this study are
completed, the data will be compared to other studies.
The burbot captured seem to be from a narrow size range, and likely represent a limited age
range. It is suspected that the burbot captured, while adults, are < 5 years old. While burbot are
typically a piscivorous species, they typically do not exhibit this feeding behavior until their 5th
to 6th year of life. Prior to becoming piscivorous, burbot have a diet similar to Arctic grayling,
longnose sucker, and other fish in the river. It would be expected then that the mercury
concentration in burbot would resemble non-piscivorous fish prior to the age of 6, and resemble
lake trout after that age. For this reason additional burbot samples (approximately 5) may need
to be collected to fully characterize the range of mercury concentration in tissues of this species.
Lake trout sampling was limited to seven fish from Deadman Lake and two fish from Sally Lake.
Mercury concentrations in lake trout can be specific to a lake, as shown in the WACAP study.
Therefore it is not known if the concentrations of mercury in the trout from Deadman Lake will
be fully representative of the concentration in other lakes (Sally Lake, Cushman Lake) in or
hydraulically connected to the inundation zone. For this reason it may be necessary to collect
approximately 5 additional lake trout from Cushman Lake and/or Sally Lake.
The literature indicates that mercury is exported downstream from reservoirs mainly by water,
with the dissolved phase (< 0.45 μm) and suspended solids (0.45 to 50 μm) accounting for 64
percent and 33 percent, respectively, of the total mercury, and plant debris, phytoplankton,
zooplankton, benthos and fish contributing only 3 percent (Schetagne et al. 2000). Therefore
predictive risk analyses for downstream receptors as requested in the April 1 SPD will
incorporate this data.
7. COMPLETING THE STUDY
[As explained in the cover letter to this draft ISR, AEA’s plan for completing this study will be
included in the final ISR filed with FERC on June 3, 2014.]
8. LITERATURE CITED
ADEC. 2012. Mercury concentration in fresh water fish Southcentral Susitna Watershed.
Personal communication with Bob Gerlach, VMD, State Veterinarian. June 2012.
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Alaska Power Authority (APA). 1984. Population Dynamics of Arctic Grayling in the Upper
Susitna Basin.1984 Report No.4, Part 2 by Dana C. Schmidt and Mike E. Stratton.
Bodaly, R.A., J.W.M. Wudd, R.J.P. Fudge and C.A. Kelly. 1993. Mercury concentrations in fish
related to size. Can. Jounal of Fish.Aquat. Sci. SO: 980-987.
Duffy L.K., E. Scofield, T. Rodgers, M. Patton, and R.T. Bowyer. 1999. Comparative baseline
levels of mercury, Hsp 70 and Hsp 60 in subsistence fish from the Yukon–Kuskokwim
delta region of Alaska. CompBiochem Physiol, Part C 1999;124:181–6.
Friedli, H. R., L.F. Radke, N.J. Payne, D.J. McRae, T.J. Lynham, and T.W. Blake. 2007.
Mercury in vegetation and organic soilat an upland boreal forest site in Prince Albert
National Park, Saskatchewan, Canada, J. Geophys. Res.-Biogeosciences, 112, G01004,
doi:10.1029/2005JG000061.
Frenzel, S.A. 2000. Selected Organic Compounds and Trace Elements in Streambed Sediments
and Fish Tissues, Cook Inlet Basin, Alaska. USGS Water-Resources Investigations
Report 00-4004. Prepared as part of the National Water-Quality Assessment Program.
Gilliom, R.J., Mueller, D.K., and Nowell, L.H. 1998.Methods for comparing water-quality
conditions among National Water-Quality Assessment study units, 1992-1995: U.S.
Geological Survey Open-File Report 97-589, 54 p.
Grigal, D.F., E.A. Nater, and P.S. Homann. 1994. Spatial distribution patterns of mercury in an
east-central Minnesota landscape. P. 305-312. In C.J. Watras and J.W. Huckabee (ed.)
Proceedings on International Conference on Mercury as a Global Pollutant. Monterye,
CA. 31 May – 4 June 1992. Electric Power Research Institute, Palo Alto, CA.
Grigal, D.F. 2003. Mercury sequestration in forests and peatlands: a review. Journal of
Environmental Quality 32:393-405.
Jewett S.C. and L.K. Duffy. 2007. Mercury in Fishes of Alaska, with emphasis on subsistence
species. Sci. Total Envir. 387(1-3): 3-27.
Jewett S.C., X. Zhang, S.A. Naidu, J.K. Kelly D. Dasher, and L.K. Duffy. 2003. Comparison of
mercury and methylmercury in northern pike and Arctic grayling from western. Alaska
rivers. Chemospere 2003;50:383–92.
Johnels A.G., T. Westermark, W. Berg, P.I. Person, and B. Sjostrand. 1967. Pike and some other
aquatic organisms in Sweden as indicators of mercury contamination in the environment.
Oikos 1967;18:323–33.
Landers, D.H. S.L. Simonich, D.A. Jaffe, L.H. Geiser, D.H. Campbell, A.R. Schwindt, C.B.
Schreck, M.L. Kent, W.D. Hafner, H.E. Taylor, K.J. Hageman, S. Usenko, L.K.
Ackerman, J.E. Schrlau, N.L. Rose, T.F. Blett, and M.M. Erway. 2008. The Fate,
Transport, and Ecological Impacts of Airborne Contaminants in Western National Parks
(USA). EPA/600/R-07/138. U.S. Environmental Protection Agency, Office of Research
and Development, NHEERL, Western Ecology Division, Corvallis, Oregon.
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Schetagne, R., J.F. Doyon, and J.J. Fournier. 2000. Export of mercury downstream from
reservoirs. The Science of the Total Environment 260 (2000): 135-145.
Snyder-Conn E. and M. Lubinski. 1993.Contaminant and water quality baseline data for the
Arctic National Wildlife Refuge, Alaska, 1988–1989.Raw Data, Ecological Services,
Fairbanks, AK, U.S. Fish and Wildlife Service, Technical Report NAES-TR-93-03, vol.
2. 1993. 305 pp.
St. Louis, V.L., J.W.M.Rudd, C.A. Kelly, K.G. Beaty, N.S. Bloom and R.J.Flett. 1994. The
importance of wetlands as sources of methylmercury to boreal forest ecosystems. Can. J.
Fish. Aquat. Sci. 51: 1065–1076.
USEPA. 2000. Guidance for Assessing Chemical Contaminant Data for use in Fish Advisories:
Volume 1 Fish Sampling and Analysis, 3rd Edition. EPA-823-B-00-007.United States
Environmental Protection Agency, Office of Water. Washington, D.C. 485p.
Zhang X., A.S. Naidu, J.J. Kelley, S.C. Jewett, D. Dasher, and L.K. Duffy. 2001. Baseline
concentrations of total mercury and methylmercury in salmon returning via the Bering
Sea (1999–2000). Mar. Pollut. Bull. 2001;42:993–7.
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9. TABLES
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Table 4.2-1. Sampling Parameters and Media
Parameter
Media
Vegetation Soil Surfacewater1 Sediment Sediment
Porewater
Piscivorous
Birds and Mammals
Fish Tissue
Filet Liver
pH X X
Water Temp X X
Hardness X X
Alkalinity X
TOC X X
DOC X X
Aluminum Total,
dissolved Total Dissolved
Arsenic Total,
dissolved Total Dissolved X
Cadmium Total,
dissolved Total Dissolved X
Calcium Total,
dissolved Dissolved
Copper Total,
dissolved Total Dissolved
Chromium Total,
dissolved Total
Iron Total,
dissolved Total Dissolved
Lead Total,
dissolved Total Dissolved
Magnesium Total,
dissolved Dissolved
Mercury Total Total Total,
dissolved Total Dissolved Total Total Total
Methyl Mercury X X X X X
Nickel Total,
dissolved Total Dissolved
Selenium Total Dissolved X
Zinc Total,
dissolved Total Dissolved
Sediment Size X
Total Solids X
1 See ISR Section 5.5 for additional parameters collected for Baseline Monthly and Focus Area Water Quality Sampling
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Table 4.2-2. Vegetation and Soil Sample Locations
Sample Site Latitude Longitude Nearest PRM
Site 1 N1 62.8206 -148.1557 200.3
Site 1 N2 62.8207 -148.1560 200.3
Site 1 N3 62.8206 -148.1553 200.3
Site1 N4 62.8207 -148.1562 200.3
Site1 N5 62.8206 -148.1552 200.3
Site 2 N1 62.7976 -148.0707 203.8
Site 2 N2 62.7975 -148.0706 203.8
Site 2 N3 62.7974 -148.0704 203.8
Site 2 N4 62.7976 -148.0708 203.8
Site 2 N5 62.7973 -148.0703 203.8
Site 2 N6 62.7973 -148.0703 203.8
Site 3 N1 62.7895 -148.0556 208.0
Site 3 N2 62.7895 -148.0561 208.0
Site 3 N3 62.7897 -148.0551 208.0
Site 3 N4 62.7896 -148.0563 208.0
Site 3 N5 62.7898 -148.0552 208.0
Site 3 N6 62.7898 -148.0552 208.0
Site 4S alt1 62.7884 -148.0074 206.2
Site 4S alt2 62.7883 -148.0077 206.2
Site 4S alt3 62.7883 -148.0071 206.2
Site 4S alt4 62.7883 -148.0079 206.2
Site 4S alt5 62.7883 -148.0068 206.2
Site 4S alt6 62.7883 -148.0068 206.2
Site 5S 1 62.7842 -147.9521 208.2
Site 5S 2 62.7845 -147.9521 208.2
Site 5S 3 62.7842 -147.9520 208.2
Site 5S 4 62.7846 -147.9524 208.2
Site 5S 5 62.7840 -147.9519 208.2
Site 6S-1 62.7790 -147.9189 209.8
Site 6S-2 62.7789 -147.9195 209.8
Site 6S-3 62.7790 -147.9185 209.8
Site 6S-4 62.7788 -147.9198 209.8
Site 6S-5 62.7792 -147.9183 209.8
Site 7 N1 62.7784 -147.8787 211.5
Site 7 N2 62.7784 -147.8787 211.5
Site 7 N3 62.7786 -147.8787 211.5
Site 7 N4 62.7782 -147.8789 211.5
Site 7 N5 62.7787 -147.8789 211.5
Site 7 N6 62.7787 -147.8789 211.5
Site 8 S1 62.7728 -147.8483 212.5
Site 8 S2 62.7729 -147.8481 212.5
Site 8 S3 62.7725 -147.8484 212.5
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Sample Site Latitude Longitude Nearest PRM
Site 8 S4 62.7731 -147.8480 212.5
Site 8 S5 62.7724 -147.8486 212.5
Site 9 N1 62.8509 -148.2314 NA
Site 9 N2 62.8508 -148.2316 NA
Site 9 N3 62.8509 -148.2311 NA
Site 9 N4 62.8510 -148.2317 NA
Site 9 N5 62.8507 -148.2310 NA
Site 9 N6 62.8507 -148.2310 NA
Site 10 N1 62.8577 -148.2133 NA
Site 10 N2 62.8574 -148.2131 NA
Site 10 N3 62.8572 -148.2134 NA
Site 10 N4 62.8576 -148.2129 NA
Site 10 N5 62.8571 -148.2136 NA
Samples collected from August 6 to 7, 2013.
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Table 4.2-3. Baseline Water Quality Monitoring Sites for Total and Dissolved Mercury
Project River Mile
(PRM)
Description Latitude Longitude Location Rationale
29.9 Susitna Station 61.544280 -150.515560 Influence of upstream tributary
32.5 Yentna River 61.587604 -150.483017 Major tributary
33.6 Susitna above Yentna 61.575950 -150.427410 Above major tributary
45.1 Deshka River 61.710142 -150.324700 Major tributary
59.9 Susitna 61.862200 -150.184630 Above major tributary
87.8 Susitna at Parks
Highway East 62.174531 -150.173677 Mainstem river site
102.8 Talkeetna River 62.342430 -150.112660 Major tributary
118.6 Chulitna River 62.567703 -150.237828 Major tributary
107 Talkeetna 62.397240 -150.137280 Downstream of existing townsite; Historic
(1980s) monitoring site
124.2 Curry Fishwheel
Camp 62.617830 -150.013730 Important side channel habitat
140.1 Gold Creek 62.767892 -149.689781 Major tributary
142.2 Indian River 62.78635 -149.658780 Major tributary
142.3 Susitna above Indian
River 62.785776 -149.648900 Historic (1980s) monitoring site
152.2 Susitna below
Portage Creek 62.830397 -149.382743 Downstream of major tributary
152.3 Portage Creek 62.830379 -149.380289 Major tributary
152.7 Susitna above
Portage Creek 62.827002 -149. 827002 Historic (1980s) monitoring site
187.2 Susitna at Watana
Dam site 62.822600 -148.553000 Boundary condition between the reservoir
and riverine models
235.2 Oshetna Creek 62.639610 -147.383109 Uppermost tributary in the Project area
Table 4.2-4. Focus Area Water Monitoring Sites for Total and Methylmercury
Focus Area (FA)
FA-104 (Whiskers Slough)
FA-113 (Oxbow I)
FA-115 (Slough 6A)
FA-128 (Slough 8A)
FA-138 (Gold Creek)
FA-141 (Indian River)
FA-144 (Slough 21)
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Table 5.1-1. Historic Mercury Concentrations at Gold Creek (PRM 140.1)
Date
Mercury in water
(filtered, µg/L)
Mercury in water
(unfiltered, µg/L)
Mercury in suspended
sediment
(µg/kg)
6/14/77 NS <0.5 NS
8/10/77 NS <0.5 NS
10/4/77 NS 0.2 NS
6/23/81 NS 0.4 0.4
7/21/81 0.2 0.3 0.1
3/30/82 <0.1 <0.1 NS
7/1/82 <0.1 0.2 NS
9/16/82 <0.1 0.2 NS
3/18/83 <0.1 <0.1 NS
6/28/83 <0.1 0.1 NS
7/28/83 <0.1 0.3 NS
6/27/84 <0.1 0.1 NS
7/25/84 0.2 3.0 NS
6/27/85 0.2 0.0 NS
7/24/85 <0.1 <0.1 0.1
8/28/85 <0.1 <0.1 NS
3/24/86 <0.1 0.1 NS
6/25/86 <0.1 <0.1 NS
7/30/86 0.2 0.1 NS
8/25/86 0.8 0.5 NS
6/6/12 <0.005 0.007 NS
8/15/12 <0.005 0.008 NS
6/6/13 <0.005 0.023 NS
NS = Not Sampled
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Table 5.1-2. Historic Mercury Concentrations at Susitna at Parks Highway East (PRM 87.8)
Date Mercury in water
(filtered, µg/L)
Mercury in water
(unfiltered, µg/L)
Mercury in suspended
sediment (µg/kg)
6/15/77 NS <0.5 NS
8/10/77 NS <0.5 NS
10/4/77 NS <0.10 NS
3/25/81 0.10 0.1 0.0
6/25/81 0.00 0.6 0.6
7/23/81 0.10 0.3 0.2
7/2/82 <0.10 0.2 NS
9/15/82 0.10 0.2 0.1
10/13/82 0.10 0.1 0.0
1/20/83 <0.10 NS NS
3/17/83 <0.10 <0.10 NS
6/24/83 <0.10 0.2 NS
7/27/83 <0.10 0.3 NS
6/14/84 <0.10 0.9 NS
7/19/85 <0.10 0.1 NS
1/10/85 <0.10 <0.10 NS
6/25/85 <0.10 0.1 NS
7/23/85 <0.10 <0.10 NS
8/27/85 <0.10 <0.10 NS
3/18/86 <0.10 <0.10 NS
6/25/86 <0.10 <0.10 NS
6/5/12 <0.005 0.015 NS
8/13/12 <0.005 0.023 NS
6/3/13 <0.005 0.035 NS
NS = Not sampled
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Table 5.1-3. Historic Mercury at Susitna Station (PRM 29.9)
Date Mercury in water
(filtered, µg/L)
Mercury in water
(unfiltered, µg/L)
Mercury in suspended
sediment (µg/kg)
1/20/75 <0.5 <0.5 0.0
5/23/75 <0.5 <0.5 0.0
8/27/75 <0.5 <0.5 0.0
10/3/75 <0.5 <0.5 0.0
3/17/76 <0.5 <0.5 0.0
5/28/76 <0.5 <0.5 0.0
7/26/76 <0.5 <0.5 0.3
10/6/76 <0.5 <0.5 0.0
3/9/77 <0.5 <0.5 NS
5/23/77 <0.5 <0.5 0.0
8/19/77 <0.5 <0.5 0.2
12/13/77 <0.1 <0.1 0.0
4/5/78 <0.1 <0.1 0.0
5/24/78 <0.1 <0.1 0.1
7/17/78 <0.1 0.2 0.1
1/15/79 <0.1 <0.1 0.1
5/14/79 <0.1 0.2 0.2
6/19/79 <0.1 <0.1 0.1
9/17/79 <0.1 <0.1 0.1
3/12/80 0.0 0.1 0.1
6/16/80 0.0 0.1 0.1
7/30/80 0.1 0.1 0.0
4/9/81 0.0 0.1 0.1
6/12/81 0.0 0.3 0.3
7/15/81 0.2 0.8 0.6
4/9/82 <0.1 <0.1 NS
5/19/82 <0.1 0.1 NS
7/14/82 0.2 0.2 0.0
10/5/82 0.1 NS NS
4/5/83 <0.1 NS NS
6/22/83 0.1 NS NS
7/27/83 <0.1 NS NS
9/30/83 <0.1 NS NS
4/6/84 <0.1 NS NS
5/18/84 <0.1 NS NS
7/18/84 <0.1 NS NS
9/20/84 <0.1 NS NS
3/27/85 0.1 NS NS
5/24/85 <0.1 NS NS
7/18/85 0.2 NS NS
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Date Mercury in water
(filtered, µg/L)
Mercury in water
(unfiltered, µg/L)
Mercury in suspended
sediment (µg/kg)
9/19/85 <0.1 NS NS
12/4/85 0.1 NS NS
7/29/86 0.1 NS NS
9/25/86 3.0 NS NS
5/30/13 <0.005 NS NS
NS= No sample
Table 5.1-4. ADEC Mercury Statewide Data (ng/g ww)
Species Tissue Number Mean and Std. Dev.
(ng/g ww)
Median
(ng/g ww)
Range
(ng/g ww)
Lake trout Fillet w hole 53
31
360 ± 180
280 ± 130
320
310
64 -740
59 -540
Grayling Fillet juvenile 48
1
87 ± 34
NA
82
48
33 -180
NA
Dolly Varden Fillet 22 120 ± 160 58 11 -550
Humpback whitefish Fillet w hole 98
24
67 ± 32
48 ± 25
66
44
8 -18
12 -120
Round whitefish Fillet 12 75 ± 56 68 8 -200
Burbot Fillet 27 330 ± 280 250 ND– 850
Longnose sucker Fillet 3 71 ± 12 73 59 -82
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Table 5.1-5. ADEC Mercury Data from Susitna Watershed
Species Site Name Fish Length (FL mm) Fish Weight (g) Age Sex Hg (ng/g dw)
Lake trout Lakes near Tyone Creek 600 2939 NM M 130
Lakes near Tyone Creek 610 3089 NM M 270
Lakes near Tyone Creek 730 5294 NM F 740
Arctic grayling Lake Louise 288 200 4.5 M 110
Lake Louise 290 230 4 M 110
Lakes near Tyone Creek 200 NM 2 NM 95
Lakes near Tyone Creek 201 NM 2 NM 91
Lakes near Tyone Creek 330 340 5 F 180
Lakes near Tyone Creek 278 200 <1 F 160
Lakes near Tyone Creek 220 110 2 M 110
Lakes near Tyone Creek 270 190 3.5 F 80
Lakes near Tyone Creek 290 230 4 NM 80
Finger Lake 370 460 7 M 67
Fishook Lake 310 310 4 F 77
Fishook Lake 370 160 7 F 100
Fishook Lake 320 350 5 M 130
Upper Talkeetna River 360 420 6.5 NM 93
Upper Talkeetna River 370 430 7 M 51
Christianson Lake 260 160 3.5 F 120
Christianson Lake 204 10 2.5 NM 130
Christianson Lake 272 190 3.5 F 59
Burbot Big Lake 579 1038 9 NM 94
Round whitefish Knob Lake 390 490 20 F 120
Knob Lake 360 310 7 F 200
Knob Lake 340 220 8 F 78
Knob Lake 320 230 6 M 58
Knob Lake 280 150 1 M 90
Coal Creek Lake 330 290 12 M 140
Coal Creek Lake 310 220 13 F 79
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Table 5.1-6. Mercury in Cook Inlet Sediments and Slimy Sculpin (Frenzel 2000)
Site Name Sediment Hg (ng/g dw) Slimy Sculpin Hg (ng/g dw)
Ninilchik River 50 150
Kenai River at Soldotna 30 200
South Fork Campbell Creek 30 210
Chester Creek 180 100
Talkeetna River 40 80
Deshka River 460 110
Moose Creek 200 160
Kamishak River 40 90
Johnson River 130 NS
Kenai River Below Russian 70 120
Kenai River at Jim’s Landing 90 140
Kenai River below Skilak Lake Outlet 70 150
Colorado Creek 180 NS
Costelllo Creek 230 80
National mean 60 NA
National mean is derived from Gilliom et al (1998)
Table 5.1-7. Mercury Partitioning in Cook Inlet Sediments and Slimy Sculpin (Frenzel 2000)
Site Name
Total Hg in
Sediment
(ng/gdw)
MeHg in Sediment
(ng/g dw)
Total Hg in Fish
(ng/g dw)
Total Hg in
Water (ng/g)
MeHg in water
(ng/g)
South Fork Campbell
Creek 200 0.67 292/429 2.50 0.02
Chester Creek 109 0.38 152/0 2.96 0.02
Deshka River 21 5.10 246 NS NS
Johnson River 50 0.01 NS 9.78 0.02
Costelllo Creek 169 0.04 0/101 4.97 0.02
Fish concentrations are for slimy sculpin/Dolly Varden
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Table 5.1-8. WACAP Data for Lichen Samples
Site Name Species Number Median Hg (ng/g ww)
NOAT Masonhalea richardsonii 3 17
NOAT Flavocetraria cucullata 2 23
GAAR Masonhalea richardsonii 2 22
GAAR Flavocetraria cucullata 4 26
DNP Masonhalea richardsonii 6 12
DNP Flavocetraria cucullata 6 21
NOAT = Noatak National Preserve; GAAR = Gates of the Arctic National Park; and DNP = Denali National Park
Table 5.1-9. WACAP Data for Alaska Fish
Site Name Species Number Mean Age Median Hg (ng/g ww)
NOAT Burial Lake Lake trout 10 19.7 129.71
GAAR Matcharak Lake Lake trout 10 17.9 217.54
DNP McLeod Lake Burbot 4 4 58.34
DNP Wonder Lake Lake trout 10 17 112.59
Results are for whole body samples.
NOAT = Noatak National Preserve; GAAR = Gates of the Arctic National Park; and DNP = Denali National Park
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Table 5.2-1. Plant Species Observed and Collected at Each Sample Site
Species Site-1 Site-2 Site-3 Site-4 Site-5 Site-6 Site-7 Site-8 Site-9 Site-10
Alder (Alnus spp.) X X X X X X X X
Willow (Salix spp.) X X O X X X X X X X
Bog Blueberry (Vaccinium uliginosum) X X X X X X X X X X
Low-bush Cranberry (Vaccinium vitus-
idaea) X X X X X X O X X
Salmonberry (Rubus spectabilis) X X
Prickly Rose (Rosa acicularis) X O X O X X
Crowberry (Empetrum nigrum) X X O O X O
American Red Currant (Ribes triste) X
Clover (Trifolium sp.) X
Spruce (Picea sp.) X O O
Sweet Gale (Myrica gale) X O
Arctic Coltsfoot (Petasites frigidus) O O O X X X
Horsetail (Equisetum sp.) O O O O O O O O
Bog Birch (Betula glandulosa) O O O O O O O O O
Bush Cinquefoil (Dasiphora fruticosa) O O O O O O
Common Labrador Tea (Ledum
groenlandicum) O O O O O O O O O
Cloudberry (Rubus chamaemorus) O O O
Wintergreen (Pyrola sp.) O O O
Dwarf Dogwood (Cornus canadensis) O O O
Soapberry (Shepherdia canadensis) O
Twisted Stalk (Streptopus amplexifolius) O
Fireweed (Chamerion angustifolium) O
Marsh Five-finger (Comarum palustre) O
Red Bearberry (Arctostaphylos rubra) O O O O O
X are plants included in the sampling. O are plants observed, but not included due to low vegetative mass.
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Table 5.3-1. Results of General Soil Characteristics
Location Sample number Lat. Long. River Mile Soil Fraction Description Moss (cm) Peat (cm) Total percent Total Solids
Site-1 N-1 62.8206 -148.1557 200.3 Silt with clay 4.50 9.5 14.0 25.05
Site-1 N-2 62.8207 -148.1560 200.3 Silt with clay 6.50 18.0 24.5 19.59
Site-1 N-3 62.8206 -148.1553 200.3 Silt with clay 5.00 13.0 18.0 20.68
Site-1 N-4 62.8207 -148.1562 200.3 Silt with clay 3.50 6.5 10.0 21.23
Site-1 N-5 62.8206 -148.1552 200.3 Silt with Clay 4.00 14.5 18.5 41.76
Site-2 N-1 62.7976 -148.0707 203.8 Silt 4.50 8.9 13.4 27.19
Site-2 N-2 62.7975 -148.0706 203.8 Silt 3.60 15.0 18.6 23.69
Site-2 N-3 62.7974 -148.0704 203.8 Clayey silt 8.50 13.0 21.5 27.93
Site-2 N-4 62.7976 -148.0708 203.8 Silt 4.80 19.0 23.8 31.25
Site-2 N-5 62.7973 -148.0703 203.8 Clayey silt 3.80 9.2 13.0 23.55
Site-2 N-6 62.7973 -148.0703 203.8 Clayey silt 3.80 9.2 13.0 19.65
Site-3 N-1 62.7895 -148.0556 208.0 Clayey silt 4.50 28.5 33.0 26.12
Site-3 N-2 62.7895 -148.0561 208.0 Clayey silt 4.50 20.5 25.0 26.02
Site-3 N-3 62.7897 -148.0551 208.0 Clayey silt 4.50 15.3 19.8 28.30
Site-3 N-4 62.7896 -148.0563 208.0 Clayey silt 3.50 9.0 12.5 28.01
Site-3 N-5 62.7898 -148.0552 208.0 Clayey silt 7.00 5.0 12.0 27.28
Site-3 N-6 62.7898 -148.0552 208.0 Clayey silt 7.00 5.0 12.0 25.91
Site-4S alt 1 62.7884 -148.0074 206.2 Silt 3.80 6.2 10.0 19.25
Site-4S alt 2 62.7883 -148.0077 206.2 Silt 12.50 4.2 16.7 22.44
Site-4S alt 3 62.7883 -148.0071 206.2 Silt 4.20 8.2 12.4 26.26
Site-4S alt 4 62.7883 -148.0079 206.2 Silt 1.90 0.0 1.9 20.32
Site-4S alt 5 62.7883 -148.0068 206.2 Silt 8.20 6.2 14.4 25.60
Site-4S alt 6 62.7883 -148.0068 206.2 Silt 8.20 6.2 14.4 26.42
Site-5S 1 62.7842 -147.9521 208.2 Silty sand 4.00 4.0 8.0 38.09
Site-5S 2 62.7845 -147.9521 208.2 Clayey silt sand 5.00 8.0 13.0 33.27
Site-5S 3 62.7842 -147.9520 208.2 Silty sand 4.50 15.0 19.5 35.95
Site-5S 4 62.7846 -147.9524 208.2 Clayey silty
sand
3.80 8.1 11.9 44.67
Site-5S 5 62.7840 -147.9519 208.2 Clayey silt 4.30 2.5 6.8 23.48
Site-6S 1 62.7790 -147.9189 209.8 Silty sand 3.50 1.0 4.5 30.25
Site-6S 2 62.7789 -147.9195 209.8 Silty sand 2.50 0.0 2.5 54.53
Site-6S 3 62.7790 -147.9185 209.8 Silt 5.50 2.0 7.5 28.91
Site-6S 4 62.7788 -147.9198 209.8 Silty sand 2.00 0.0 2.0 29.87
Site-6S 5 62.7792 -147.9183 209.8 Clayey silt 6.00 10.0 16.0 23.90
Site-7 N-1 62.7784 -147.8787 211.5 Silt 4.30 0.0 4.3 18.44
Site-7 N-2 62.7784 -147.8787 211.5 Silt 3.50 0.0 3.5 19.47
Site-7 N-3 62.7786 -147.8787 211.5 Silt 6.00 0.0 6.0 20.71
Site-7 N-4 62.7782 -147.8789 211.5 Silt 4.50 5.0 9.5 23.41
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Location Sample number Lat. Long. River Mile Soil Fraction Description Moss (cm) Peat (cm) Total percent Total Solids
Site-7 N-5 62.7787 -147.8789 211.5 Silt 3.80 0.0 3.8 23.61
Site-7 N-6 62.7787 -147.8789 211.5 Silt 3.80 0.0 3.8 19.50
Site-8 S-1 62.7728 -147.8483 212.5 Silt 3.50 0.0 3.5 37.62
Site-8 S-2 62.7729 -147.8481 212.5 Silt 4.00 0.0 4.0 26.54
Site-8 S-3 62.7725 -147.8484 212.5 Silt 4.00 0.0 4.0 42.70
Site-8 S-4 62.7731 -147.8480 212.5 Clayey Silt 3.80 0.0 3.8 28.67
Site-8 S-5 62.7724 -147.8486 212.5 Clayey silt 3.50 0.0 3.5 35.36
Site-9 N-1 62.85085 -148.2314 NA Clayey silt 3.50 7.5 11.0 27.66
Site-9 N-2 62.85083 -148.2316 NA Silt 3.00 6.5 9.5 32.48
Site-9 N-3 62.85089 -148.2311 NA Silt 3.50 11.5 15.0 17.51
Site-9 N-4 62.85104 -148.2317 NA Clayey silt 4.00 9.5 13.5 25.17
Site-9 N-5 62.85074 -148.2310 NA Clayey silt 6.00 7.5 13.5 30.99
Site-9 N-6 62.85074 -148.2310 NA Clayey Silt 6.00 7.5 13.5 26.73
Site-10 N-1 62.8577 -148.2133 NA Clayey Silt 7.00 6.5 13.5 27.14
Site-10 N-2 62.8574 -148.2131 NA Clayey Silt 5.50 7.5 13.0 27.85
Site-10 N-3 62.8572 -148.2134 NA Clayey Silt 4.50 6.8 11.3 29.75
Site-10 N-4 62.8576 -148.2129 NA Clayey Silt 4.50 6.5 11.0 25.24
Site-10 N-5 62.8571 -148.2136 NA Clayey Silt 2.5 1.5 4.0 23.98
Table 6.1-1 Mercury in Soil and Vegetation (Friedli et al. 2007)
Media Hg (ng/g, dw)
39 year old stand
Hg (ng/g, dw)
133 year old stand
Hg (ng/g dw)
180 year old stand
Moss 94.5 108 90.6
Aspen leaves NS 8 NS
Spruce needles 9.9 NS NS
Aspen bark NS 15.9 NS
Jack pine bark 38.6 NS NS
Lichen 30.6 74 227.1
Leaf litter 68.3 NS 127.1
Aspen wood NS 2.08 NS
White spruce wood 1.86 NS NS
Organic soil 100-160 120 - 300 160-250
Mineral soil 9.2 8.8 25.2
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10. FIGURES
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Figure 3-1. Water Quality Sample Locations
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Figure 4.2-1. Vegetation and Soil Sampling Locations
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Figure 4.2-2. Vegetation and Soil Sample Location: Site 1
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Figure 4.2-3. Vegetation and Soil Sample Location: Site 2
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Figure 4.2-4. Vegetation and Soil Sample Location: Site 3
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Figure 4.2-5. Vegetation and Soil Sample Location: Site 4
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Figure 4.2-6. Vegetation and Soil Sample Location: Site 5
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Figure 4.2-7. Vegetation and Soil Sample Location: Site 6
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Figure 4.2-8. Vegetation and Soil Sample Location: Site 7
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Figure 4.2-9. Vegetation and Soil Sample Location: Site 8
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Figure 4.2-10. Vegetation and Soil Sample Location: Site 9
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Figure 4.2-11. Vegetation and Soil Sample Location: Site 10
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Figure 4.2-12. Overview of Focus Area Sampling Locations
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Figure 4.2-13. Map of sediment/porewater sampling locations
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Figure 4.2-14. Sediment and Porewater Sample Locations for Goose and Jay Creeks
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Figure 4.2-15. Sediment and Porewater Sample Locations for Kosina Creek and Oshetna River
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Figure 4.2-16. Fish Tissue Sample Collection Locations
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Figure 5.1-1. ADEC Fish Tissue Sample Collection Locations
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Figure 5.1-2. USGS (Frenzel 2000) Sample Locations
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Figure 5.7-1. Lake Trout Fork Length and Age (Burr 1987)
Figure 5.7-2. LNS Fork Length and Age in the Upper Susitna (APA 1984)
Various Sustina
Drainage Lakes
Deadman Lake
0
100
200
300
400
500
600
700
800
900
1000
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INITIAL STUDY REPORT MERCURY ASSESSMENT AND POTENTIAL FOR BIOACCUMULATION STUDY (5.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 60 February 2014 Draft
Figure 5.7-3. Arctic Grayling Fork Length and Age in the Upper Susitna (APA 1984)
Figure 5.7-4. Round Whitefish Fork Length and Age in Middle Susitna (APA 1984)
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