HomeMy WebLinkAboutSuWa207sec7-7Alaska Resources Library & Information Services
Susitna-Watana Hydroelectric Project Document
ARLIS Uniform Cover Page
Title:
Glacier and runoff changes study, Study plan Section 7.7 : Initial study
report, Literature review
SuWa 207
Author(s) – Personal:
Author(s) – Corporate:
Division of Geological & Geophysical Surveys, Alaska Department of Natural Resources
University of Alaska Fairbanks
AEA-identified category, if specified:
Draft initial study report
AEA-identified series, if specified:
Series (ARLIS-assigned report number):
Susitna-Watana Hydroelectric Project document number 207
Existing numbers on document:
Published by:
[Anchorage : Alaska Energy Authority, 2014]
Date published:
February 2014
Published for:
Alaska Energy Authority
Date or date range of report:
Volume and/or Part numbers:
Study plan Section 7.7
Final or Draft status, as indicated:
Draft
Document type:
Pagination:
vi, 50 p.
Related work(s):
Pages added/changed by ARLIS:
Notes:
All reports in the Susitna-Watana Hydroelectric Project Document series include an ARLIS-
produced cover page and an ARLIS-assigned number for uniformity and citability. All reports
are posted online at http://www.arlis.org/resources/susitna-watana/
Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Glacier and Runoff Changes Study
Study Plan Section 7.7
Initial Study Report – Literature Review
Prepared for
Alaska Energy Authority
Prepared by
Division of Geological & Geophysical Surveys
Alaska Department of Natural Resources
& University of Alaska Fairbanks
February 2014 Draft
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page i February 2014 Draft
TABLE OF CONTENTS
Executive Summary ..................................................................................................................... vi
1. Introduction ....................................................................................................................... 1
2. Study Objectives................................................................................................................ 2
3. Study Area ......................................................................................................................... 2
4. Glaciers .............................................................................................................................. 3
4.1. Glacier Changes in Alaska .................................................................................3
4.2. Runoff from Glaciers .........................................................................................4
4.2.1. Characteristics of Glacier Discharge ...............................................4
4.2.2. Effects of atmospheric warming on glacier runoff ..........................5
4.2.3. Modeling Glacier Runoff .................................................................6
4.2.4. Previous Glacier Runoff Studies ......................................................8
5. Permafrost ....................................................................................................................... 11
5.1. Trends in Permafrost ........................................................................................11
5.2. Controls on Permafrost ....................................................................................12
5.3. Periglacial Landforms ......................................................................................13
5.4. Permafrost Modeling .......................................................................................13
6. Hydrology ........................................................................................................................ 14
6.1. Runoff ..............................................................................................................14
6.2. Surface Water and Wetlands ............................................................................15
6.3. Groundwater and Infiltration ...........................................................................15
6.4. Evapotranspiration ...........................................................................................16
7. Climate ............................................................................................................................. 16
7.1. Observed Changes in Climate ..........................................................................16
7.2. Existing Meteorological and Climatological Data ...........................................17
7.2.1. Station Observations ......................................................................17
7.2.2. Historical Observations in the Susitna Basin .................................17
7.2.3. Gridded Datasets ............................................................................18
7.3. Projections of Future Climate ..........................................................................18
8. Discussion......................................................................................................................... 19
9. Literature Cited .............................................................................................................. 20
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page ii February 2014 Draft
10. Tables ............................................................................................................................... 32
11. Figures .............................................................................................................................. 38
LIST OF TABLES
Table 4.1-1. Reported studies of regional-scale glacier mass changes in Alaska (including the
adjacent glaciers in northwestern Canada). .................................................................................. 32
Table 4.2.4.2-1. Summer, winter and annual mass balances in meters water equivalent for the
four major glaciers in the Susitna River Basin. ............................................................................ 33
Table 7.3. Total runoff measured at several stream gauges and the estimated runoff contributions
from the glacierized area in the Susitna River Basin. ................................................................... 33
Table 7.2.2-1. Meteorological stations used to record climatic data from 1980 to 1984 in the
Susitna River Basin by R&M Consultants, Inc. ........................................................................... 34
Table 7.2.2-2. Individual sources for recovered climate data from the Susitna basin during the
period 1980-1984. ......................................................................................................................... 34
Table 7.2.3-1. Overview of gridded Climate Products for Alaska. ............................................. 36
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iii February 2014 Draft
LIST OF FIGURES
Figure 2.1. Susitna Glacier and other unnamed glaciers contributing to Upper Susitna River
drainage. ........................................................................................................................................ 38
Figure 4.1-1. 100-year projections of glacier volume in Alaska using 14 Global Climate Models
forced by the RCP4.5 emission scenario. ..................................................................................... 39
Figure 4.2.2-1. Variations in glacier runoff and mass balance. ................................................... 40
Figure 4.2.2-2. Schematic representation of the long-term effects glacier mass loss on: a) glacier
volume; and b) glacier runoff. ...................................................................................................... 41
Figure 4.2.2-3. Initial effects of atmospheric warming on glacier runoff including feedback
mechanisms leading to further enhanced runoff totals and peak flows (Hock et al. 2005). ......... 42
Figure 4.2.3.3-1. Concept of linear reservoirs as applied to glaciers using one to three (c-a)
different linear reservoirs. ............................................................................................................. 43
Figure 4.2.4.2-1 Map of the upper Susitna basin, including the locations of historical
meteorological, stream gauge and glacier monitoring stations. .................................................... 44
Figure 5-1. Permafrost distribution in the upper Susitna basin. ................................................... 45
Figure 7.2.1-1. Coverage of temperature and precipitation data at 33 Climate Stations in and in
proximity of the Upper Susitna Basin. .......................................................................................... 46
Figure 7.2.1-2. Period of record for temperature measurements collected during the 1980s in the
Susitna basin. ................................................................................................................................ 47
Figure 7.2.2-1. Air temperature in degrees Celsius at the six climate stations monitored from
1980 to 1984. ................................................................................................................................ 48
Figure 7.2.2-2. Recovered Snow Depth Measurements (1981 and 1982; source: R&M
Consultants, Inc. 1982). ................................................................................................................ 49
Figure 7.3-1. Comparisons of annual mean precipitation during 1994-2004 from the global
reanalysis (2.5ox2.5o), 30km and 10km downscaling (topography in black contour and
precipitation in color) (Zhang et al. 2007a). ................................................................................. 50
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page iv February 2014 Draft
LIST OF ACRONYMS, ABBREVIATIONS, AND DEFINITIONS
Abbreviation Definition
ablation All processes that reduce the mass of the glacier. Glacier mass reduction occurs through the
loss of snow and ice by melting, sublimation and calving.
albedo A measure of the reflectivity of a surface, expressed as the fraction of the incoming solar
radiation reflected by the surface.
aufeis Sheet-like masses of layered ice that forms from successive flows of groundwater issuing at
the surface during freezing temperatures.
evapotranspiration The water loss from the surface to the atmosphere via evaporation and transpiration. The
sum of evaporation and transpiration.
firn The compacted snow on a glacier that remains after at least one year’s ablation season, but
has not yet metamorphosed into glacier ice.
frost blister A seasonal frost mound produced through doming of seasonally frozen ground by a
subsurface accumulation of water under elevated hydraulic potential during progressive
freezing of the active layer.
jökulhlaup A sudden outburst flood of water orginating from a glacier melted during a volcanic eruption.
Also used when water filling an ice-dammed lake bursts out of the damned portion of the lake
resulting in flooding.
lithalsa A frost-induced raised land form in permafrost areas with mineral-rich soils, where a
perennial ice lens has developed within the soil.
moulin A deep pothole or shaft that allows supraglacial meltwater to enter a glacier.
nunatak An island of bedrock which projects above the glacier, icefield or icesheet’s surface and is
completely surrounded by the ice.
palsa A peaty permafrost mound containing a core of alternating layers of segregated ice and peat
or mineral soil material.
periglacial Describes cold, non-glacial landforms, climates, geomorphic processes or environments.
permafrost Ground that has remained continuously below 0°C for at least two consecutive years.
pingos A low hill or mound containing a core of massive perennial ice covered with soil and
occasionally vegetation.
talik An unfrozen section of ground found above, below, or within a layer of discontinuous
permafrost or beneath a body of water in continuous permafrost due to a local anomaly in the
thermal, hydrological, hydrogeological or hydrochemical conditions.
AEA Alaska Energy Authority
FERC Federal Energy Regulatory Commission
ISR Initial Study Report
RSP Revised Study Plan
SPD Study Plan Determination
WaSiM Water Balance Simulation Model
NMFS National Marine Fisheries Service
ILP Initial Study Report
GRACE Gravity Recovery and Climate Experiment
km Kilometer
mm Millimeter
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page v February 2014 Draft
Abbreviation Definition
Gt Gigaton
GCM General Circulation Model
RCP Representative Concentration Pathways
UBC University of British Columbia
V-A Volume-Area
V-L Volume-Length
w.e.q Water equivalent
US United States
LIA Little Ice Age
W Watt
m Meter
K Kelvin
PDO Pacific Decadal Oscillation
ET Evapotranspiration
PET Potential Evapotranspiration
AET Actual Evapotranspiration
D Dimensional
C Celcius
NOAA National Oceanic and Atmospheric Administration
NCDC National Climatic Data Center
SNOTEL Snow Telemetry
NCEP National Centers for Environmental Prediction
NCAR National Center for Atmospheric Research
SNAP Scenarios Network for Alaska and Arctic Planning
IPCC Intergovernmental Panel on Climate Change
ECHAM5, GFDL21, MIROC,
HAD and CCCMA General Circulation Models
CORDEX Coordinated Regional Climate Downscaling Experiment
NARCCAP North American Regional Climate Change Assessment Program
A2, A1B and B2 Emission Scenarios
CMIP Coupled Model Intercomparison Project
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page vi February 2014 Draft
EXECUTIVE SUMMARY
Glacial Runoff Changes Study – Literature Review 7.7
Purpose Glaciers, permafrost, and the hydrologic cycle are expected to change in response to
anticipated future atmospheric warming by the end of this century, thus impacting
water yields to the proposed Susitna-Watana hydroelectric reservoir. This study is
designed to review existing literature relevant to glacier retreat in southcentral Alaska
and the upper Susitna watershed and to summarize the current understanding of
potential future changes. A broader ongoing study that is not part of the FERC
approved study plan, aims to quantify future changes in glacier wastage, surface and
groundwater, permafrost, and evapotranspiration and their combined effect on runoff
into the proposed reservoir.
Status This portion of study is complete. This report completes an analysis of relevant
literature review and a summary of findings about potential future changes in runoff
associated with literature review.
Study
Components
FERC’s study plan determination required AEA to undertake one of the study’s
proposed components, which was to conduct a literature review relevant to glacial
retreat and also summarize the understanding of potential future changes in runoff
associated with glacier wastage and retreat.
2013 Variances There were no variances to this study as described in RSP Section 7.7.4.
Steps to Complete
the Study
This FERC required portion of this study is complete.
Highlighted
Results and
Achievements
In this review, we present background information, derived from published literature
and data reports, on key aspects of basin hydrology as it applies to the upper Susitna
drainage basin, Alaska.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 1 February 2014 Draft
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 within the RSP was the Glacier and Runoff
Changes Study, Section 7.7. RSP Section 7.7 focuses on understanding how changes to the
Upper Susitna basin hydrology due to glacial retreat and climate change can affect Project
operations and environmental resources.
On February 1 2013, FERC staff issued its study plan determination (February 1 SPD) for 44 of
the 58 studies, approving 31 studies as filed and 13 with modifications. RSP Section 7.7 was one
of the 13 approved with modifications. In the February 1 SPD, FERC recognized the following:
AEA proposes to analyze the potential effects of climate change on glacier wastage and retreat
and the corresponding effects on streamflow entering the proposed reservoir, and evaluate the
effects of glacial surges on sediment delivery to the reservoir.
Specifically, AEA proposes to:
1. review existing literature relevant to glacier retreat in southcentral Alaska and the upper
Susitna watershed and summarize the current understanding of potential future changes
in runoff associated with glacier wastage and retreat;
2. develop a hydrologic modeling framework that utilizes a glacier melt and runoff model
(Hock 1999) and a Water Balance Simulation Model (WaSiM) to predict changes in
glacier wastage and retreat on runoff in the Susitna basin;
3. simulate the inflow of water to the proposed reservoir and predict changes to available
inflow using downscaled climate projections up to the year 2100; and
4. analyze the potential changes to sediment delivery from the upper Susitna watershed into
the reservoir from glacial surges.
FERC staff recommended the following in the February 1 SPD.
• We find that the analysis of the potential changes to sediment delivery from the upper
Susitna watershed into the reservoir from glacial surges as proposed by AEA is
necessary, and therefore, are recommending approval of this portion of AEA’s proposed
study (item 4 as described above in the applicant’s proposed study).
• We are not recommending approval of the remainder of AEA’s proposed study (items 1-3
as described above in the applicant’s proposed study). We have no objection to AEA
conducting this portion of the study.
• We do not recommend extending the geographic range of the climate change assessment
or adding an analysis of the natural resource impacts, as recommended by the NMFS
and others.
On February 21 2013, the National Marine Fisheries Service (NMFS) filed a notice of study
dispute pursuant to section 5.14(a) of the Commission’s regulations regarding FERC’s failure to
require AEA to implement the three study components related to glacier runoff and climate
change that AEA proposed in the RSP (item 1). A Dispute Resolution Panel Meeting and
Technical Conference was held on April 3 2013 to discuss NMFS’ modification requests. On
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 2 February 2014 Draft
April 26 2013 FERC provided its Study Dispute Determination, requiring the following
modification;
We recommend that AEA review existing literature relevant to glacial retreat and summarize the
understanding of potential future changes in runoff associated with glacier wastage and retreat,
as described in RSP section 7.7.4.1.
On May 28 2013, NMFS and the Center for Water Advocacy (Center) filed requests for
rehearing of the formal study dispute determination issued on April 26 2013. NMFS and the
Center sought rehearing of the Director’s finding that studies proposed by the potential applicant,
AEA, and NMFS related to global climate change are unnecessary to conduct the Commission’s
environmental analysis and therefore will not be required to be conducted by AEA. On July 18
2013, FERC rejected the Center’s request for rehearing and denied NMFS’ request for rehearing.
AEA has adopted the RSP as the Final Study Plan with no modifications. This is the final report
of the results of the literature review thus completing the FERC-approved study. The results of
the literature review are presented below in Sections 4–7.
2. STUDY OBJECTIVES
The primary goal of this study is to analyze the potential impacts of glacier wastage and retreat
on the Susitna-Watana Hydroelectric Project (Project). Specifically, how will glacier wastage
and retreat, along with associated changes to the climate, affect the flow of water into the
proposed reservoir? Currently several glaciers flow down the southern flanks of the Alaska
Range near 13,832-foot Mount Hayes to form the three forks of the Upper Susitna River (Figure
2-1).
Glaciers in this area provide a significant portion of the total runoff within the Upper Susitna
drainage, and it is well documented that these glaciers are currently retreating (Molnia 2008).
Given this trend, changes to the runoff represented by glacial melting may occur in the future
and may affect the Project. Therefore, it is important to understand how changes to the upper
basin hydrology, due to glacier wastage and retreat and climate change can affect Project
operations and environmental resources.
Specific objectives of the study are as follows:
• Review existing literature relevant to glacier retreat in south-central Alaska and the
Upper Susitna watershed. This review will summarize the current understanding of
potential future changes in runoff associated with glacier wastage and retreat.
Other objectives of the study that AEA is proceeding with are not part of the formal study for the
ILP, but will be reported on in future years based on the work outlined in RSP Section 7.7.4.
3. STUDY AREA
The proposed study area is the Susitna River basin upstream of the proposed Watana Dam site.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 3 February 2014 Draft
4. GLACIERS
Glaciers are significant contributors to seasonal river discharge in many parts of the world,
serving as frozen reservoirs of water that supplement runoff during warm and dry periods in
which there is low flow. Glaciers in northern high-latitude regions have been experiencing
increasingly negative cumulative mass balances since the early 1990s (Wolken et al. 2013). This
trend is anticipated to continue as a consequence of global climate warming, as predicted
unambiguously by all current climate models, and is expected to cause accelerated glacier
wastage and retreat, thus reducing the storage capacity of snow and ice. As a result, river
discharge volumes and timing in seasonal river runoff will change, and glaciers’ ability to buffer
this flow against seasonal precipitation extremes will be reduced or lost.
4.1. Glacier Changes in Alaska
Glaciers in Alaska (including northwest Canada) cover ~86,700 km2 corresponding to 12% of all
glacierized areas in the world outside the vast Greenland and Antarctic ice sheets (Pfeffer et al.
in press). Roughly 14% of the area is drained through 50 tidewater glaciers. The mass balance of
a glacier is a measure of the glacier’s health and is defined as the change in the mass of a glacier
over a stated period of time (Cogley et al. 2011). Alaskan glaciers have shown a coherent signal
in glacier mass loss during the last several decades with acceleration of mass loss during the last
two decades. Alaskan glaciers currently exhibit the highest glacier wastage rates on Earth
(Gardner et al. 2013). Current annual thinning rates reach several meters per year for some
glaciers that terminate near sea level (Van Looy et al. 2006; Larsen et al. 2007). During 1995 to
2001, annual volume loss from Alaskan glaciers equaled 0.27±0.1 mm/yr sea-level equivalent
(Arendt et al. 2002) and added ~100 km3 yr-1 to the freshwater discharge budget for the Gulf of
Alaska watershed (Arendt et al. 2002). This runoff volume corresponds to about 50% of the
annual discharge of the Yukon River (Raymond et al. 2007).
A revised estimate using US Geological Survey maps and satellite derived digital elevation
models indicate mass losses of 42±9 Gt/yr during 1962 to 2006 (Berthier et al. 2010). Gardner et
al. (2013) estimates a mass budget of -50± 17 Gt yr-1 for the period 2003-2009 based on
evaluation of several published estimates from the Gravity Recovery and Climate Experiment
(GRACE). However, GRACE estimates of mass loss vary widely in Alaska due to a combination
of factors (i.e. different spatial and temporal resolutions; Table 4.1-1); more research is needed to
resolve the discrepancies.
Average thinning rates vary widely across Alaska, but a pattern of recent acceleration is found
uniformly. The mass changes are consistent with global atmospheric warming trends. Low-
elevation climate station data in Alaska and northwestern Canada indicate that, during the period
1950 – 2002, winter and summer temperatures increased by about 2.08 ± 0.88 and 1.08 ± 0.48
°C, respectively, and precipitation may have increased in most parts (Arendt et al. 2009).
However, climate-glacier interactions are complex and the precise causes of the observed glacier
changes need further investigation.
Alaskan glaciers are expected to continue losing mass in the future (Radic and Hock 2011). 100-
year projections of the Alaskan’s glacier contribution to sea level rise indicate that Alaska is one
of the largest regional contributors with multi-model volume losses varying from 18% to 45% by
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 4 February 2014 Draft
2100 in response to temperature and precipitation projections of 14 general circulation models
(GCMs) and the Representative Concentration Pathways (RCP) 4.5 and RCP8.5 emission
scenarios (Radic et al. 2013; Figure 4.1-1).
4.2. Runoff from Glaciers
4.2.1. Characteristics of Glacier Discharge
Glaciers significantly modify streamflow both in quantity and timing, even with low percentages
of catchment ice cover (e.g., Meier and Tangborn 1961; Fountain and Tangborn 1985; Chen and
Ohmura 1990; Hopkinson and Young 1998; see Hock et al. 2005 for review). Glaciers are stores
of water, amassing and releasing water on a wide range of time scales, thus, modulating basin
hydrology through distinct characteristics of glacier runoff. Distinct characteristics of glacier
runoff include (Röthlisberger and Lang 1987; Hock et al. 2005):
• Annual runoff: Annual runoff from glacierized basins is modulated by the glaciers’ mass
balances, i.e. the changes in glacier mass over time. Runoff is reduced in years of positive
mass balance, as water is withdrawn from the hydrological cycle and put in temporary
storage. In contrast, runoff is enhancedduring years of negative glacier mass balance
since water kept in storage is released, producing more total runoff than in years of
positive balance under otherwise similar conditions (Figure 4.2.2-1);
• Diurnal cycles: Glacier runoff is characterized by pronounced melt-induced diurnal
cyclicity. Daily peak flows may increase by several hundred percent of daily minimum
flows during days without rainfall;
• Seasonal variations: Glacier runoff shows distinct seasonal variations with very low
winter runoff and a pronounced and seasonally delayed summer peak compared to non-
glacierized basins (Escher-Vetter and Reinwarth 1994). While runoff from the glacier is
minimal during the winter season of snow accumulation, runoff is large during the melt
season, when melt of winter snow, firn and ice enhance down-glacier river flows;
• Interannual variability: Glacier cover dampens year-to-year variability in streamflow; a
minimum is reached at 10-40% of glacierization with increasing variability with both
lower and higher degrees of ice cover (Lang 1986). This so-called ‘glacier compensation’
effect occurs because in hot and dry years, glacier melt offsets reduced precipitation
inputs;
• Runoff correlation: Runoff from highly glacierized basins often correlates with air
temperature, while glacier-free basins tend to show positive correlations between runoff
and precipitation;
• Outburst floods: Glaciers may also cause sudden floods, often referred to as jökulhlaups,
posing a potential hazard for downstream populations and infrastructure. These outburst
floods may be due to subglacial volcanic eruptions or sudden drainage of sub-glacial,
moraine and ice-dammed lakes (e.g., Lliboutry et al. 1977; Bjornsson 2003).
In addition to contributing directly to runoff through ice wastage, glacier cover within a drainage
basin decreases direct evaporation and plant transpiration, the combination of which can result in
considerably higher water yields for basins with glaciers compared to unglacierized watersheds
(Hood and Scott 2008). Furthermore, the proportion of streamflow derived from glacier runoff
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 5 February 2014 Draft
has pronounced effects on physical (Kyle and Brabets 2001), biogeochemical (Hodson et al.
2008; Hood and Berner 2009; Bhatia et al. 2013) and biological (Milner et al. 2000; Robinson et
al. 2001) properties of streams. Consequently, changes in watershed glacier cover also have the
potential to alter riverine material fluxes. For example, area-weighted watershed fluxes of
soluble-reactive phosphorus decrease sharply with declining ice cover (Hood and Scott 2008).
Recent studies also suggest that dissolved organic material contained in glacial runoff has a
microbial source and is highly labile to marine heterotrophs (Hodson et al. 2008; Hood et al.
2009).
4.2.2. Effects of atmospheric warming on glacier runoff
The response of glacier runoff to climate changes is complex and will depend on the time-scale
considered. Although the mass change response is immediate, some runoff response-variables
will change sign at a later stage when enhanced melt rates have caused glacier volume to
decrease significantly (Hock et al. 2005).
As climate changes and causes glacier mass balances to become progressively more negative,
total glacier runoff will initially increase due to enhanced glacier melt rates (Jansson et al. 2003;
Figure 4.2.2-2). In highly glacierized catchments runoff due to glacier mass loss may contribute
a substantial fraction of annual water yields. Enhanced melt rates are caused primarily by
atmospheric warming but are further accelerated by positive feedback mechanisms. For example,
enlargement of bare ice areas due to faster removal of winter snow or loss of firn area will cause
reduced albedo, thus increasing the amount of absorbed shortwave radiation and melt (Figure
4.2.2-3).
The glacier will respond to prolonged glacier net mass loss by dynamically adjusting its size and
shape generally through retreat and thinning. While the mass loss in response to climate forcing
is immediate, the geometric adjustment is delayed by the glacier’s characteristic response time
(Johannesson et al. 1989). The initial increase in runoff will be followed by a reduction in runoff
as the glacier dwindles and eventually disappears (Figure 4.2.2-2). Hence, the ability of the
glacier to augment streamflow in periods of otherwise low flow will be diminished and
eventually lost. With high percentage of ice cover, the initial increase in runoff can be substantial
and result in a higher frequency of flood events that might not be triggered by rainfall events.
The timing of the turning point between runoff increase and decrease will depend on the
competing effects of increased glacier thinning rates due to increased melt and decreased total
melt water due to depletion of the glacier storage, which in turn is governed by both glacier and
climate change characteristics. Anticipating the timing of the peak in runoff and the rate of
decline in runoff following that peak are key questions in long-term water resource planning (e.g.
hydropower development). The replacement of ice by coastal temperate forest and alpine
vegetation may lead to further reduced water yields and a major change in catchment-wide
nutrient cycling (Wolken et al. 2011).
Warming air temperatures prolong the melt season by causing earlier melt onset and later freeze-
up (Sharp and Wolken 2011), thus modifying the timing of the seasonal glacier runoff peak. In
addition, the pronounced daily cyclicity typical of glacier discharge will, at least in an initial
phase, be amplified due to increased daily melt water production and feedback mechanisms. This
increases the risk for floods substantially, especially when strong melt-induced flows coincide
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 6 February 2014 Draft
with heavy rain events. Feedbacks include more efficient water transport through the glacier as
snow and firn layers that typically have large water retention capacity are removed more quickly,
and melt waters are evacuated via efficient tunnel systems through the glacier ice (Figure
4.2.2-3; Braun et al. 2000; Willis et al. 2002).
4.2.3. Modeling Glacier Runoff
Glacier runoff has been modeled using stochastic, conceptual and physically based models (see
Hock et al. 2005 for review). Stochastic models were widely used in the 1960s and 1970s for
seasonal and short-term runoff forecasts often tailored to the needs to hydropower facilities. The
models compute runoff directly as a function of meteorological variables based on multiple
regression techniques (Lang 1968; Jensen and Lang 1973; Ostrem 1973). In contrast, conceptual
and physical-based models attempt to compute the individual processes leading to glacier runoff.
Here, the modelling of glacier runoff and its response to climate change involves three principal
steps (Hock et al. 2005): modelling of (a) glacier mass balance, i.e. the changes in the glacier’s
mass over the hydrological year; (b) the geometric adjustments of the glacier in response to
glacier mass changes; and (c) the routing of melt and rain water through the glacier, i.e.
transformation of water inputs into a discharge hydrograph down glacier. Glaciers are often only
crudely represented in hydrological models. While many existing watershed models include
routines for snow and ice melt, the geometric adjustments and glacier specific discharge routing
are often ignored entirely or treated in very rudimentary ways, inhibiting accurate modeling of
the modulating effects of glaciers on watershed runoff.
4.2.3.1. Glacier Mass Balance
Mass balance models generally fall into two categories: (a) temperature-index models based on
air temperature as the primary index of melt energy (Hock 2003); and (b) physically based
energy balance models computing all relevant components of the energy balance (Hock 2005a).
Although the latter more adequately describe the physics of the processes involved, considerably
larger data requirements often inhibit their use. Nevertheless, despite their simplicity
temperature-index models have been shown to perform surprisingly well in hydrological
modeling on catchment scales. However, they are less suitable to model the diurnal cyclicity of
glacier runoff or the accurate representation of the spatial variation in melt rates across a basin.
To improve the physical representation of processes while retaining low data requirements, a
complete hierarchy of melt models have been developed with a gradual transition from simple
degree-day approaches to energy-balance-type expressions by increasing the number of input
variables into model formulations. For example, the UBC-runoff-model (Quick and Pipes 1977)
and the HYMET-runoff-model (Tangborn 1984) employ the daily temperature range in addition
to air temperature as climatic input for their melt routines, a measure of cloud-cover and, hence
solar radiation. Hock (1999) varied the degree-day factor as a function of potential direct solar
radiation, thus significantly improving the modeling of both the spatial melt variations and the
diurnal melt and glacier discharge amplitudes. This model is also included in WaSIM.
Pellicciotti et al. (2005) elaborated on this approach by including parameterized shortwave
radiation fluxes. Temperature-index models are widely used, promoted by ease of application
and low data input requirements. However model parameters are often not transferable between
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 7 February 2014 Draft
catchments (MacDougall et al. 2011), and it remains unclear how model parameters will change
under a different climate, a limitation that needs further research.
4.2.3.2. Geometric Adjustments
Glacier retreats to higher altitudes exert a negative, i.e. stabilizing, feedback on glacier mass
change because loss of area at predominantly lower elevations will make the average thinning
less pronounced than it would have been without retreat under the same climate conditions.
Glacier thinning, in contrast, exerts a positive, i.e. self-amplifying, feedback; with decreasing
surface elevation, the glacier is exposed to higher air temperatures, resulting in more negative
mass balances. The net effect of these two opposing feedbacks will depend on a number of
factors related to climate, glacier geometry and characteristics such as debris coverage
(Bodvardsson 1955; Harrison et al. 2001; Huss et al. 2012). It is crucial to model the geometry
changes resulting from climate change to be able to account for the mass-balance feedback and
to model the turning point beyond which glacier runoff decreases (Figure 4.2.2-2).
Ideally the dynamical adjustment is calculated using physically-based numerical ice flow
models. Such models solve a momentum balance equation, either the Stokes equations or an
approximation thereof, however, detailed data requirement restrict their use in hydrological
modeling. The most common approach to account for the glacier's dynamical adjustments as its
mass changes is volume-area (V-A) or volume-length (V-L) scaling (Bahr et al. 1997). The
annual volume change computed from the mass-balance model is subtracted from total glacier
volume, and scaling is applied to derive a new area from the updated glacier volume. In case of
volume loss, elevation bands or grid cells at lower elevations are then removed from the glacier
domain.
Huss et al. (2010) suggested an approach of intermediate complexity, distributing the annual
volume loss across the glacier surface based on observed typical elevation change patterns,
which indicate generally low thinning rates at high elevations and strongly accelerated thinning
rates at low elevations. An empirical function relating glacier surface elevation change to
normalized elevation range is applied each year to adjust the elevation of each glacier grid cell.
Each grid cell with a modeled elevation drop exceeding the current ice thickness is removed
from the glacier, thereby also modeling glacier retreat. This approach has successfully been
tested on smaller retreating glaciers, but does not provide a mechanism for glacier advance.
4.2.3.3. Discharge Routing
Detailed modeling of the physical processes involved in the transfer of water through a glacier is
highly complex. Such models need to account for the time-transgressive growth and decay of
conduits and passages through and under the deformable ice, and account for occurrence of
crevasses, moulins and other entry points where water can enter the glacier system. Only few
such glacier models exist (e.g. Arnold et al. 1998; Flowers and Clarke 2002), and generally are
used as research tools rather than for routing water through glaciers in watershed models.
Instead, most hydrological models (if they include specific water routing through glaciers at all)
adopt the widely used concept in hydrological internal flow routing of linear reservoirs (Chow et
al. 1988). The glacier is divided into one or several parallel or serial reservoirs, each of which
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 8 February 2014 Draft
can be thought of a container of water where outflow is proportional to the stored water volume,
which in turn depends on input from melt and rain water. Each reservoir is assigned a unique
storage constant that represents the time shift between the centroid of the inflow and that of the
outflow thus delaying the reservoir’s outflow. A number of variants of this approach have been
suggested (Figure 4.2.3.3-1), often assigning different storage constants based on the surface
types of the glacier. For example, higher storage coefficients are applied for the snow and firn
zones than for bare ice, reflecting their profoundly higher water retention capacity. Storage
constant are often treated as model parameters obtained from model calibration. Despite its
simplicity and pronounced changes in a glacier’s internal drainage system throughout the melt
season, the approach performs remarkably well (Hock and Noetzli 1997; Escher-Vetter 2000).
4.2.4. Previous Glacier Runoff Studies
A large number of studies around the world have highlighted the role of glaciers in the
hydrological cycle and indicated significant hydrological changes in response to climate change,
including changes in total water amounts and seasonality as described above (e.g., Braun et al.
2000; Casassa et al. 2009; Rees and Collins 2006; Hagg et al. 2006; Horton et al. 2006; Yao et
al. 2007; Huss et al. 2008; Immerzeel et al. 2008; Koboltschnik et al. 2008; Stahl et al. 2010;
Kobierska et al. 2013). Results vary with regard to the importance of glacier runoff relative to
total runoff in glacierized catchments (Weber et al. 2010; Huss 2011). This can at least partially
be explained by varying physical factors such as climate regimes, catchment size, degree of
glacierization or glacier mass change rates. However, some of these differences are due to the
different ways to define glacier runoff. Definitions of glacier runoff fall into two principal
categories (Radic and Hock 2013): (1) those that only consider the net mass loss component of a
glacier due to glacier wastage, i.e. runoff is zero if the glacier is in balance or gains mass; and (2)
those that consider all meltwater originating from a glacier no matter the magnitude or sign of
the mass budget. Glacier runoff generally is much larger if the latter definition is adopted than
the former. Hence, the relative importance of glacier runoff to total runoff will differ between
these two approaches.
Observations from gauge records in glacierized basins show both increases in runoff, for
example, along the coast in southern Alaska (Neal et al. 2002), northwestern British Columbia
(Fleming and Clarke 2003) or on the Tibetean Plateau (Yao et al. 2007), and negative trends in
summer streamflow, for example in the southern Canadian Cordillera (Stahl and Moore 2006).
The long-term effect of runoff reduction, resulting from a decrease in glacierized area, was also
detected by Chen and Ohmura (1990), who analyzed multi-decadal discharge records in the
Swiss Alps. Comeau et al. (2009) analyzed annual runoff in a large catchment in western Canada
and found that reductions in glacier volume, due to receding glaciers, contributed 3% to total
runoff during 1975-1998.
Various studies have modeled the impacts of future climate change on runoff in glacierized
basins. To provide information in connection with a hydropower scheme, Adalgeirsdottir et al.
(2006) modeled an increase in annual glacier runoff from ice caps in Iceland of up to 60% until
about 2100, followed by a rapid reduction in runoff thereafter. Rees and Collins (2006) applied a
hydro-glaciological model to hypothetical catchments with varying fractional ice area in the
Himalayas and predicted gradual runoff increase over the next ~50 years, followed by a more
abrupt runoff decline to lower than contemporary values over the next few decades. Stahl et al.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 9 February 2014 Draft
(2008) investigated the sensitivity of streamflow in response to changes in climate and glacier
cover for the Bridge River basin in British Columbia, coupling a hydrological model with a
glacier response model. Under the assumption of current climate, the model projected decreases
in glacier area by 20% over the next 50 to 100 years causing a similar percentage decrease in
summer streamflow.
Recent investigations in the monsoon-effected regions High Asian Mountains indicate that
glacier melt may be of lesser importance than previously assumed since monsoon rains and
glacier melt will continue to sustain the increasing water demands expected in these areas
(Kaser et al. 2010; Immerzeel et al. 2013). In contrast a number of studies have investigated the
hydrological consequences of continued glacier wastage in the tropical Andes in response to
climate change in individual watersheds where glacier melt often is the only source of water
during the dry season. Juen et al. (2007) and Vuille et al. (2008) used historical hydrological
records and found a decrease in glacier runoff as glaciers shrank and strongly enhanced
seasonality. Baraer et al. (2012) found that annual discharge in the investigated watersheds in
Peru’s Cordillera Blanca will be lower than present by 2-30%, with considerably more
pronounced effects during the dry season. Several recent studies have highlighted the potential of
glacier retreat in modulating runoff regimes, and indicated serious adverse effects on water
availability if glacier recession continued (e.g. Pouyaud et al. 2005, Juen et al. 2007; Mark and
Seltzer 2003; Mark and McKenzie 2007; Suarez et al. 2008; Kaser et al. 2010).
Even in non-arid regions the glacier contribution to river runoff can be substantial. Huss (2011)
assessed the contribution of glaciers to runoff from large-scale drainage basins in Europe with
areas up to 800,000 km2 over the period 1908-2008 based on modeled monthly mass budget
estimates for all glaciers in the European Alps. The glacier runoff defined as the water due to
glacier net mass change was computed for each month and compared to monthly river runoff
measured at gauges along the entire river lengths. Although ice cover of the investigated basins
did not exceed 1% of the total area, the maximum monthly glacier contributions during summer
ranged from 4% to 25% between catchments, emphasizing that seasonal glacier contributions
can be significant even in basins with little ice cover.
4.2.4.1. Alaska
Few studies have quantified the effect of glaciers on Alaskan rivers. Neal et al. (2002) note an
increase in runoff in some gauge records for glacier streams along the coast in southern Alaska.
Several studies documented the impact of glacier water on the biogeochemical properties of
Alaska streams (e.g. Hood and Scott 2008; Hood and Berner 2009). Neal et al. (2010) adopted a
water balance approach to estimate the contribution of glacier runoff to freshwater discharge into
the Gulf of Alaska; a 420,230 km2 watershed covered 18% by glaciers. Glacier runoff (defined
as all water including melt and rain water from the glacier area) contributed 47% of the total
runoff (870 km3 a-1), while 10% came from glacier net mass loss alone.
4.2.4.2. Upper Susitna Basin
Between 1981 and 1983, a joint effort between the University of Alaska Fairbanks and R&M
Consultants, Inc. on behalf of the Alaska Power Authority (now Alaska Energy Authority) was
made to analyze the runoff contributions produced from glaciers in the Susitna River Basin. The
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 10 February 2014 Draft
project goal was to determine the timing and amount of glacier runoff in order to aid
development of water forecast models for the proposed Susitna hydroelectric dam. This study
focused on the four major glaciers located on the southern side of the Eastern Alaska Range at
the Susitna River and Maclaren River headwaters. These glaciers are: West Fork Glacier, Susitna
Glacier and its Northwest and Turkey Tributaries, East Fork Glacier and Maclaren Glacier. The
glaciers in the Talkeetna Mountains or Eureka Glacier were not included in this study.
The mass balance of the glaciers was determined by the glaciological method, i.e. measuring
accumulation and ablation at stakes and in snow pits. The amount of snow and ice that had
accumulated and melted was measured at each stake at specific times in the hydrologic year.
This method is used to monitor the change in the glacier surface relative to a datum registered to
the stake drilled into the glacier. During this study, three stakes were placed on each of the major
glaciers at different elevations by mountaineers who used topographic maps to determine site
elevations. One mass balance stake was placed in the ablation zone near 1000 m, one stake was
placed at the equilibrium line of the glaciers near 1500 m, and another stake was set in the
accumulation zone near 2000 m. Since the mass balance stake distribution was one stake per 50
km2, the mass balance monitoring efforts were considered to be at the reconnaissance level
(Clarke et al. 1985). The stakes were typically measured during the spring in April or May,
during the summer in late August or early September. The sparse stake measurements of snow
depth were supplemented by probing to the late-summer surface.
Mean snow density was used to convert the mass balance stake measurements to water
equivalent balances. The mean snow density was calculated by measuring snow density as a
function of depth from samples taken in snow pits dug near representative stakes and from cores
of the entire snowpack. In May 1981, the winter snowpack and balance (1980 to 1981) was
estimated from snow stratigraphy by identifying the late-summer surface while probing snow
depth and from the snow pit measurements (Clarke et al. 1985). Snow temperatures versus depth
were assessed in snow pits; by May, the snow was isothermal at 0°C (Harrison et al. 1983). The
mean snow density used in spring and late-summer mass balance calculations was 400 kg/m3,
500 kg/m3 for mid-summer calculations, and 200 kg/m3 for fall calculations. Over the three-year
observation period, the annual balances are 0.1 ± 0.6 m w.eq./yr. The winter and summer
balances, and the annual balances for each glacier are summarized in Table 4.2.4.2-1.
Glacier runoff was compared to stream gauges in the Susitna River at Gold Creek, Susitna River
at the Denali Highway, and at the Maclaren River on the Denali Highway gauge
(Figure 4.2.4.2-1). Approximately 34% of the runoff measured north of the Denali Highway
(using Susitna River at Denali and Maclaren River at Denali stream gauges) was attributed to the
glacierized area. The average runoff from the melting of snow, firn and ice was 1.3 m/yr, nearly
1.4 times greater than the runoff contribution from the non-glacierized area above the Denali
Highway (0.95 m/yr). The glacier runoff component was approximately 2.5 times greater (13%
of total runoff) than the volume contribution from the non-glacierized basin upstream of the Gold
Creek stream gauge (Clarke et al. 1985). The primary glacier melt season during the period of
study was during July and August, when 75% of the glacier meltwater was generated. The
remainder was produced during the late spring in May and June, and in the fall before the winter
freeze-up in November (Clarke et al. 1985).
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 11 February 2014 Draft
Runoff from liquid precipitation was calculated from the high elevation Susitna Glacier climate
station monitored by R&M Consultants, Inc (Figure 4.2.4.2-1). This station was located at 1433
m on a nunatak between Susitna Glacier and its Northwest Tributary. Several assumptions used
in calculating rainfall over the glacierized basin are described in more detail in Clarke et al.
(1985). From this rain gauge, a lower-limit on the precipitation runoff is 0.25 m/yr.
5. PERMAFROST
Permafrost is defined as any parent material that remains below 0˚C for more than two
consecutive years. About 85% of Alaska is within permafrost zones, while glaciers cover ~5% of
the state. There are four permafrost distribution classes that are typically used: continuous, where
>90% of the land surface is underlain by permafrost; discontinuous, between 50 and 90%;
sporadic, between 10 and 50%; and isolated, between 0 and 10% (Figure 5-1; Jorgenson et al.
2008). The majority of the upper Susitna basin is estimated to be underlain by discontinuous and
continuous permafrost.
Permafrost has been a topic of discussion in the US and mainly Alaska, since the discovery of
gold in Fairbanks. The main focus has been on permafrost engineering, e.g. the construction of
mine shafts, rail and road systems. Many questions remain about the dynamic nature of
permafrost, not only in applications of modern day infrastructure design and resilience, but also
in other scientific disciplines, including biology, ecology, hydrology and atmospheric sciences.
A lot has been learned over the last century, and the last few decades, when the attention of
climate change has brought a wider audience to permafrost science.
5.1. Trends in Permafrost
During past glacial periods, air and permafrost temperatures were much lower than today. The
last event that cooled the ground significantly was the Little Ice Age (LIA; ca. 1600-1800). Most
shallow permafrost (<100 m) that exists in Interior Alaska were formed during the LIA
(Romanovsky et al. 2010). Evidence suggests that permafrost warming and degradation in
Interior Alaska began about 250 yrs ago (mid-1700s) and was associated with periods of
relatively warm climate during the mid-late 1700s and 1900s (Jorgenson et al. 2001).
Measurements and model simulations of the 19th and 20th centuries show periods of warming and
stagnation of permafrost temperatures in Interior Alaska. Numerical model simulations suggest
that permafrost warmed in the late 1960s and early 1970s in response to warmer air temperature
and an increase in snow cover, but were nearly stable in the 1980s (Osterkamp and Romanovsky
1999). Measurements show permafrost warming since the late 1980s in Interior Alaska
throughout the Tanana River region, in the region south of the Alaska Range from Tok westward
to Gulkana (in the Copper River Valley) and beyond to the Talkeetna Mountains (Osterkamp
2005). Near Healy, this permafrost warming (since the late 1980s) also resulted in thawing from
the top of the permafrost of about 10 cm/yr (Osterkamp 2005), which was almost entirely
attributed to increased snow cover (Osterkamp 2007). In Gulkana, however, permafrost has been
thawing from the bottom at a rate of 4 cm/yr since the 1980s and has accelerated to 9 cm/yr after
2000 (Osterkamp 2005). Interior Alaska permafrost has also experience degradation from both
the top and bottom. Although initiated in the 1700s, permafrost degradation (from the top) has
increased rapidly in the recent decades (Jorgenson et al. 2001). Continued thawing of permafrost
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 12 February 2014 Draft
will significantly alter the soil moisture, and the biogeochemical and hydrological cycles in
Interior and south-central Alaska (Wolken et al. 2011).
5.2. Controls on Permafrost
The permafrost distribution and conditions are forced by upper (air) and lower (geothermal)
boundary conditions, which are modified by snow, vegetation, and soil properties as described
below:
Air temperature - The permafrost thermal regime is mainly a result of mean annual air
temperature as it is the driving force to ground cooling or warming. Given enough time (decades
to centuries), the ground temperature will become approximately the same as the air temperature
on a mean annual basis. Accordingly, large-scale climate patterns control the thermal regime of
permafrost;
Geothermal heat flux - Permafrost is warmed from below by geothermal heat flow. The
geothermal heat flow varies across Alaska (and the planet) due to the thickness of the earth’s
crust. This can lead to various permafrost thicknesses in areas with the same vegetation, soil and
mean annual air temperature (Jafarov et al. 2012);
Snow - Snow distribution has a major warming effect on permafrost temperatures as snow is an
effective insulator during the cold season. The thermal effects of snow on ground temperatures
depend upon the timing, duration, accumulation history, and characteristics of snow (Goodrich
1982). Snowpack heterogeneity across the landscape makes it challenging to accurately predict
permafrost temperatures at fine geographical scales. Snow accumulation can be highly variable
across local (~meters) to regional (km’s) scales due to surface roughness (topography,
vegetation) and atmospheric circulation (Liston and Sturm, 2002). Redistribution of snow
through wind can create major snow drifts or snow-free areas due to repeated wind scouring.
Redistribution of snow is often accompanied with sublimation when the moisture deficit in the
air is high;
Vegetation - Vegetation is a major modifier on ground thermal regime as permafrost in the
discontinuous permafrost zone can be present or absent in areas with identical climate,
demonstrating the importance of biophysical factors (Shur and Jorgenson 2007). Especially
mosses have a major impact on soil temperatures (Kade et al. 2006) due to their large porosity
and therefore, large seasonal variation in moisture content. The overall thermal effect of mosses
is ground cooling, which favors permafrost. The distribution of discontinuous permafrost is also
controlled by aspect, which likewise plays a large role in the distribution of vegetation in Interior
Alaska;
Soils - Soils controls soil temperatures mainly through pore size distribution, composition and
amount of organic material. The soil’s modifying prosperities on heat flow results in a thermal
offset, which is defined as the difference between the mean annual surface temperature and the
mean annual top of permafrost temperature. This difference is caused by the thermal
conductivity of thawed versus frozen soils. In summer the pores are filled with liquid water that
has a thermal conductivity of 0.6 W/(m2*K), and in winter, the water is frozen and has a thermal
conductivity of 2 W/(m2*K). Based on the soil type and its porosity, the bulk thermal
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 13 February 2014 Draft
conductivity can range from 0.4 W/(m2*K) in thawed peat to 3.5 W/(m2*K) in pure granite.
Porous soils, such as peat, leads to a greater difference in thawed versus frozen thermal
conductivity, favoring cooling of the ground. Liquid water in soils also has a major impact on the
heat capacity and latent heat released during freezing. Both these factors play a major role in the
development of the active layer during the summer (higher ice content delays thaw) and it can
prevent refreezing of the soil during the next winter resulting in a talik (multiyear unfrozen layer
surrounded by permafrost). Taliks can have a major impact on the surface and groundwater
hydrology of permafrost regions.
5.3. Periglacial Landforms
Periglacial landforms can alert the observer to the presence of permafrost. Most periglacial
features are the result of soil movement related to repeated freezing and thawing, which is
associated with expanding and shrinking of soil due to the presence of water. A common feature
that forms due to shrinking of the ground during extremely cold conditions are ice wedges. The
ice wedges form polygonal pattern that can be visible on the ground surface. During past cold
periods, e.g. the Pleistocene, ice wedges formed in regions that are currently too warm for ice
wedge growth. Inactive ice wedges can be found today in all of the permafrost zones in Alaska
as massive ground ice features. Active layer processes that are also part of the periglacial
landscape include nonsorted circles, sorted circles, solifluction lobes, gelifluction lobes, frozen
debris lobes, rock glaciers and sorted strips. Many of these features are driven by temperature
changes over time (seasonal to centennial) and they affect the formation of massive ground ice,
which, unlike temperature, cannot be easily described or measured in permafrost. Artesian
groundwater flow to the surface can lead to the development of aufeis (a surface ice deposit),
frost blister (an ice deposit below the vegetation that looks like a blister), frost mound (small ice-
cored mound), palsa (ice-cored peat mound), lithalsa (ice-cored mineral mound), or pingos (large
ice-cored mounds).
5.4. Permafrost Modeling
Basic permafrost models include only two variables to simulate the soil thermal regime, the
mean annual air temperature and the geothermal temperature gradient. From these two variables,
permafrost temperatures can be estimated for any place where the mean annual air temperature is
below freezing. This approach ignores most of the aspects of what controls permafrost
distribution (see the modifiers described above), but could be used when no other data are
available. Ultimately, knowledge is required about the geothermal heat flux, soil, surface
properties, snow depth and density (Jafarov et al. 2012). Over the last few decades, the amount
of data available to develop such datasets has increased dramatically due to the use of remote
sensing techniques.
Surface and groundwater movement and storage is controlled by permafrost distribution. Current
theory on the behavior of thermo-hydrological coupled models is advancing, but insufficient
computational capability still represents a major challenge to creating simulations of large
regions at a fine enough resolution to fully couple the two processes. Daanen et al. (2008)
modeled the water movement in the active layer with a fully coupled three dimensional model
during freezing in order the better understand the behavior of non-sorted circles at the decimeter
scale. A coarser approach was taken to simulate the Alaska and circumpolar permafrost domain
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 14 February 2014 Draft
to develop an understanding of the water balance in the active layer (Rawlins et al. 2013).
However, the coarser approach leaves many aspects of the dynamic surface conditions
unanswered, which can have important feedbacks on the long- and short term state of permafrost.
6. HYDROLOGY
The hydrology of Interior and south-central Alaska is strongly influenced by seasonal to
centennial variations in cryospheric components (i.e., snow, ice and permafrost). Permafrost and
frozen ground are relatively impermeable layers (if ice rich) that restrict recharge, discharge,
infiltration and movement of groundwater, by acting as a confining layer (Williams 1970).
Glaciers are frozen reservoirs of water that can modify the streamflow from seasonal to
centennial time scales (Fountain and Tangborn 1985). Both glaciers and permafrost are abundant
in the Susitna basin and are expected to modify its hydrologic cycle as they continue to respond
to climate change.
6.1. Runoff
Permafrost strongly affects summer runoff response to storm events. The presence of permafrost
leads to a reduced basin storage, which in turn, increases surface runoff (Dingman et al. 1971;
Haugen et al. 1982; Slaughter et al. 1983). Flood hydrographs for catchments underlain by
permafrost tend to be flashier and more responsive than those from permafrost-free catchments
(Slaughter and Kane 1979) due to the limited storage capacity of the active layer.
Like other major river systems in Interior Alaska, the streamflow in the Susitna River is
characterized by a high rate of discharge from May through September and by low flows from
October through April. About 86% of the total annual flow of the upper Susitna occurs from
May through September (Alaska District, Corps of Engineers 1975). Winter snowpack in the
Alaska Range determines the magnitude of early spring discharge; summer temperatures and
precipitation determine the magnitude and duration of summer flow, and precipitation during the
late summer/early autumn promotes any elevated magnitude or duration of late-season discharge
(Ford and Bedford 1987). In large rivers that have their headwaters in mountainous, glacierized
regions, e.g. the Susitna River, the timing of peak flows is not restricted to the spring snowmelt
as heavy rainfall in summer and early fall add to high-elevation glacial wastage and snowmelt
contributions (MacKay et al. 1973). Variations in the timing of river break-up, freeze-up and
magnitude of snowmelt peaks in the Susitna River have been linked to shifts in the PDO (Pacific
Decadal Oscillation) (Curran 2012).
Although glaciers cover only ~5 % of the Susitna basin, together with the adjacent mountain
terrain, they contribute a disproportionate fraction of the average annual streamflow (see Glacier
section). Roughly 38% of the streamflow at Gold Creek originates above the gauging stations on
the Maclaren River near Paxson and on the Susitna River near Denali, although these gauging
sites cover only 20% of the basin area (R&M Consultants and Harrison 1981). The Susitna
glaciers alone (snow, firn and ice) are estimated to contribute about 13% of the annual runoff
measured at the Devils Canyon (Figure 4.2.4.2-1; Bowling 1982 and Table 7.3; Clarke et al.
1985).
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 15 February 2014 Draft
6.2. Surface Water and Wetlands
Surface water, groundwater and permafrost play a major role in nourishing wetlands in the
Susitna basin. The presence of permafrost supports extensive wetlands in areas that are otherwise
considered semi-arid as water is retained near the ground surface due to the limited subsurface
storage capacity of the active layer (Callegary et al. 2013). In discontinuous permafrost regions,
aspect can determine the presence or absence of permafrost, which in turn influences the
distribution of wetlands (Dingman and Koutz 1974).
Artesian discharge of subpermafrost groundwater is known to occur in several regions and to be
related to both lake and wetland formation in Interior Alaska (Cederstrom 1963; Kane and
Slaughter 1973; Racine and Walters 1994). If permafrost degrades, surface water may either
increase or decrease depending on the pressure of the underlying groundwater. In many cases,
subpermafrost groundwater is artesian, which results in lake-levels rising. If the hydraulic
gradient is downwards, the lake-levels will drop and permafrost can aggrade (re-grow).
6.3. Groundwater and Infiltration
Groundwater in permafrost zones occurs above (suprapermafrost), below (subpermafrost), and
locally within (talik) permafrost. Groundwater recharge, whether it is to an aquifer above (within
the active layer) or below the permafrost, is controlled by the amount of surface water that is
available for infiltration and by the hydraulic conductivity of the soils. Frozen soils with high ice
content have substantially lower infiltration rates than thawed soils and frozen soils with low
pore ice content and (Kane and Stein 1983a; 1983b). Accordingly, soils that have ice-saturated
pores are nearly impermeable. Ice saturated soils typically occur at the top of the permafrost or in
near-surface soils that experience a snowmelt that is preceded by a wet fall season. However,
frozen silts with low moisture content can readily accept snowmelt at rates greater than the snow
can melt (Kane and Stein 1983b). The partitioning of the snowmelt water into groundwater
recharge or surface runoff is, therefore, partly controlled by the moisture status of the frozen
soils.
Recharge and discharge of water to and from the larger regional aquifers located below the
permafrost are limited to the unfrozen zones that perforate the permafrost such as beneath
streams, snowbanks, lakes, glaciers and south-facing slopes. The Tanana River, north of the
Alaska Range, has a permafrost-free zone beneath it (Williams 1970), due to the local thermal
anomaly caused by the river. Susitna River is most likely experiencing a similar phenomenon,
which would allow the surface water in the river to connect with the underlying aquifer.
Headwaters draining the north facing slopes of the Alaska Range, such as the Delta River and
Jarvis Creek, are elevated above the regional aquifer with wells having static water levels as
much as 61 m below the streambeds (Dingman et al. 1971; Wilcox 1980). Both Delta River and
Jarvis Creek are influent, e.g. they lose water to the aquifer, once the rivers enter more permeable
sediments (Wilcox 1980). It is possible that a similar hydrologic system is encountered in the
upper Susitna basin.
In Interior Alaska, heat from groundwater may contribute to permafrost degradation because the
groundwater is relatively warm (2–4 °C) year-round (Jorgenson et al. 2001). Similar to the
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 16 February 2014 Draft
lowlands of the Tanana River basin, groundwater springs surface in numerous places in the
upper Susitna basin and are easily identifiable in the winter due to localized melt.
6.4. Evapotranspiration
Evapotranspiration (ET) represents the water loss from the surface to the atmosphere via
evaporation and transpiration. Refined ET assessments are difficult to obtain due to the
expensive techniques (eddy covariance) used in directly measuring ET (Aubinet et al. 2012), and
to the rough assumptions that are built into simpler techniques, which are typically used in
estimating ET. The most widely used approaches calculate the potential evapotranspiration
(PET), e.g. the upper limit for water losses to the atmosphere. PET should not be confused with
actual evapotranspiration (AET), which can be dramatically lower than PET. The loss of water
from the surface to the atmosphere is driven by available energy and vapor gradients, but
modified by a series of complex processes such as leaf stomata, soil moisture, etc. The most
commonly used equations for calculating ET include: (1) Thornthwaite's potential
evapotranspiration as it only relies on air temperature; (2) Hamon, which in addition to air
temperature requires day length; and (3) closing the water balance equation with ET, which
builds in the assumption of no storage change and integrates all errors associated with
precipitation, runoff and storage change into the estimated ET. Iwata et al. (2012) measured the
ET of a black spruce forest near Fairbanks, Alaska using the eddy covariance technique and
found cumulative ET (snow-free period) ranging from 195 mm to 234 mm (average of 211 mm)
with a typical maximum of 2.5 mm day-1 in July (year 2003-2009). In comparison, PET
estimates of the upper Susitna basin ranges between 300 to 450 mm yr-1 (Patrick and Black 1968;
http://www.snap.uaf.edu/data.php). The range in total precipitation is documented to be much
larger than both measured evapotranspiration and estimated potential evapotranspiration in
Interior Alaska (Iwata et al. 2012), suggesting an annual 1D water balance (precipitation minus
potential evapotranspiration) to range between 25 and 300 mm in the upper Susitna basin (Ford
and Bedford 1987).
7. CLIMATE
7.1. Observed Changes in Climate
Mean annual surface air temperature over northern high-latitude land areas (>60 °N) has
increased by ~2.0 °C since the mid-1960s (Overland et al. 2012). In Alaska, weather station
observations from 1949-2012 show a mean annual surface air temperature increase of 1.6 °C, a
warming that appears to be unprecedented in at least the last 400 years (Overpeck et al. 1997;
Kaufman et al. 2009). Mean annual air temperature has increased by ~1.3 °C during the past 50
years in Interior Alaska and by ~2.0 °C in inland south-central Alaska, with the greatest warming
occurring in winter (Hartmann and Wendler 2005; Shulski and Wendler 2007). By the end of the
21st century, air temperature in this region of Alaska is projected to increase by 3 to 7 °C (Walsh
et al. 2008). Projected increases in winter precipitation during this same time period could be
offset by less summer precipitation (Karl et al. 2009; ACIA 2005).
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 17 February 2014 Draft
7.2. Existing Meteorological and Climatological Data
The meteorological and climatological knowledge of inter-mountain south-central Alaska,
including the upper Susitna basin, is generally poor due largely to the sparse and poorly
distributed (mostly low elevation) data and the lack of consistent, long-term measurements.
Available meteorological measurements (historic and current) and gridded climate products
applicable to the Susitna basin are summarized below.
7.2.1. Station Observations
Daily time series for precipitation and minimum and maximum air temperature are available for
32 climate stations in or in proximity of the Upper Susitna Basin from the National Oceanic and
Atmospheric Administration (NOAA) National Climatic Data Center (NCDC; Figure 7.2.1-1).
Additional daily meteorological data is available from a National Water and Climate Center
SNOTEL station (Monahan Flat). Seven climate stations (Monahan Flat, Gracious House, Alpine
Creek Lodge, Maclaren River, Tyone Lake, Lake Susitna and Lake Louise) are located within
the upper Susitna basin, but show intermittent measurements throughout the period of record
(Figure 7.2.1-2). Meteorological observations within the Susitna River basin are available from
1980-1984 (described below).
Precipitation is an important influence on the basin hydrology of northern high-latitude
watersheds. However, biases towards systematic underestimation of precipitation are well known
and due to the documented undercatch of precipitation gauges, and is especially the case for solid
precipitation (Black 1954; Hare and Hay 1971; Benson 1982). Since snow is such a significant
part of the annual meteorologic input of water (Dingman et al. 1971), these errors strongly affect
the uncertainty of water balance calculations. Further, despite the knowledge of orographic
forcing of precipitation, most precipitation gauges (and especially long-term installations), are
located in valley bottoms due to logistical constraints. Accordingly, it is challenging to construct
total precipitation for a watershed that is dominated by complex topography (e.g. the Susitna
River basin).
7.2.2. Historical Observations in the Susitna Basin
As part of the early 1980s Susitna hydropower studies (as described above), many agencies
participated in gathering field data to meet the FERC licensing requirements. These data were
used to assess the hydrologic resources and aid the stream flow forecasting for future dam
operations. In order to supplement climate data provided by NOAA, R&M Consultants, Inc.
constructed six climate stations within the Susitna River Basin that recorded meteorological
parameters in hourly time steps from 1980 to 1984 (Figure 4.2.4.2-1). One high-elevation
climate station was installed in the Eastern Alaska Range near the confluence of the four major
glaciers that contribute runoff to the Susitna River, two climate stations were installed in the
Upper Susitna River Basin, one station was placed at the proposed Watana dam site, and two
stations were installed downstream of the dam site (Table 7.2.2-1). At each climate station,
meteorological observations of air temperature, wind speed and direction, relative humidity,
precipitation, and solar energy were recorded. Air temperature at the six climate stations
monitored from 1980 to 1984 is shown in Figure 7.2.2-1. Except for the climate data gathered
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 18 February 2014 Draft
between 1981- 1982, meteorological data were published in separate annual reports for each
station (Table 7.2.2-2).
In addition to meteorological data, the Susitna hydropower studies also measured mass balance
on glaciers in the upper basin (see section in Glaciers) and recorded a total of 165 snow depth
measurements from 16 locations (on and off glacier) in the upper basin during 1981 and 1982
(Figure 7.2.2-2; R&M Consultants Inc. 1982).
The historic data from the 1980s Susitna hydropower studies are important for calibrating the
hydrological model for the current Glacier and Runoff Changes study.
7.2.3. Gridded Datasets
Weather and climate data can also be represented spatially in the form of continuous grids of
pixels. These datasets typically describe basic statistics of meteorological variables over a daily
or monthly time step, and are generated by combining observations of meteorological variables
at ground- and ocean-based stations. Gridded datasets are particularly useful in Alaska, where
few ground observations exist. Table 7.2.3-1 lists some of the most commonly used gridded
datasets for Alaska.
7.3. Projections of Future Climate
General circulation models (GCMs) are the most widely used tools to help understand and assess
climate variability and change. However, the enormous mathematical complexity and limited
computational resources generally prevent GCMs from resolving processes at a high spatial
resolution.
The coarse resolution (100s of km) of the GCMs hinders their capability to capture detailed
mesoscale weather systems and finer scale meteorological conditions. A comparison (Figure 7.3-
1) of the annual mean precipitation resolved by the National Centers for Environmental
Prediction - National Center for Atmospheric Research (NCEP-NCAR) global reanalysis
(Kalnay et al. 1996) and mesoscale model downscaling at different resolutions over Alaska
(Zhang et al 2007a,b) further demonstrates that the finer scale structures associated with terrain
effects can only be captured in the high-resolution simulations. This discrepancy caused by the
coarse resolution of GCMs limits their application and suitability for understanding and
assessing regional and local scale climate variability and changes.
Downscaling methodologies (e.g., statistical or dynamical) are used to quantitatively obtain
regional and local scale climate change information from coarse resolution GCM outputs.
Statistical downscaling techniques such as those used in Scenarios Network for Alaska and
Arctic Planning (SNAP) climate dataset. The SNAP dataset include years 1980-2099 and are
downscaled to 2 km grid cells. Future projections from SNAP are derived from a composition of
the five best-ranked GCMs (out of 15 used by the Intergovernmental Panel on Climate Change;
IPCC) models for Alaska. Based on how closely the model outputs matched climate station data
for temperature, precipitation, and sea level pressure for the recent past, their individual ranking
order for overall accuracy in Alaska and the far north was as follows: 1) ECHAM5 2) GFDL21,
3) MIROC, 4) HAD, and 5) CCCMA. The five-model composite uses mean values from the
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 19 February 2014 Draft
outputs of these models. Results from three emission scenarios (A2, A1B and B2) are available
from the SNAP website (http://www.snap.uaf.edu/home). Dynamical regional climate
downscaling technique is commonly applied to better represent and understand the local weather
systems and associated impacts (Bengtsson et al. 1996, Lynch et al. 1998, Zhang et al. 2007a, b).
The Coordinated Regional Climate Downscaling Experiment (CORDEX,
http://wcrp.ipsl.jussieu.fr/cordex/about.html) and the North American Regional Climate Change
Assessment Program (NARCCAP, http://www.narcacap.ucar.edu) are such efforts. The
downscaled domains included in CORDEX are mainly for the continental regions around the
world and the NARCCAP covers most of North America. Unfortunately, a complete Alaska
downscaling is not included in either CORDEX or NARCCAP efforts, further downscaling of
the most recent CMIP5 simulations (fifth phase of the Coupled Model Intercomparison Project),
an important resource for the IPCC fifth assessment report, is not planned in NARCCAP, thus
necessitating further downscaling activity focused on the CMIP5 simulations for Alaska.
8. DISCUSSION
The FERC-required portion of this study is complete and the results of the larger study will be
used to help in the assessment of project effects on the hydroelectric reservoir and operational
planning.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 20 February 2014 Draft
9. LITERATURE CITED
ACIA. 2005. Arctic climate impact assessment. Cambridge University Press.
Adalgeirsdottir, G., T. Johannesson, H. Bjornsson, F. Palsson and O. Sigurosson. 2006.
Response of Hofsjokull and southern Vatnajokull, Iceland, to climate change. Journal of
Geophysical Research: Earth Surface. 111(F3), doi:10.1029/2005JF000388.
Alaska District, Corps of Engineers. 1975. Draft environmental impact statement: Hydroelectric
Power development: Upper Susitna River basin Southcentral railbelt area, Alaska. Alaska
District, Corps of Engineers. P. 98. Anchorage, Alaska.
Arendt, A.A., K.A. Echelmeyer, W.D. Harrison, C.S. Lingle and V.B. Valentine. 2002. Rapid
wastage of Alaska glaciers and their contribution to rising sea level. Science. 297(5580),
382-386. doi:10.1126/science.1072497.
Arendt, A.A., J. Walsh and W.D. Harrison. 2009. Changes of glaciers and climate in
Northwestern North America during the late twentieth century. Journal of Climate.
22(15), 4117-4134. doi:10.1175/2009JCLI2784.1.
Arnold, N., K. Richards, I. Willis and M. Sharp. 1998. Initial results from a distributed,
physically based model of glacier hydrology. Hydrological Processes. 12(2) 191-219.
doi:10.1002/(SICI)1099-1085(199802)12:2<191::AID-HYP571>3.0.CO;2-C.
Aubinet, M., T. Vesala and D. Papale (eds.). 2012. Eddy covariance: a practical guide to
measurement and data analysis. Springer.
Bahr, D., M. Meier and S. Peckham. 1997. The physical basis of glacier volume-area scaling.
Journal of Geophysical Research-Solid Earth. 102(B9) 20355-20362.
doi:10.1029/97JB01696.
Baraer, M., B.G. Mark, J.M. McKenzie, T. Condom, J. Bury, K.-I. Huh, C. Portocarrero, J.
Gómez and S. Rathay. 2012-02-01T00:00:00. Glacier recession and water resources in
Peru's Cordillera Blanca. Journal of Glaciology. 58(207), 134-150.
doi:doi:10.3189/2012JoG11J186.
Bengtsson, L., M. Botzet and M. Esch. 1996. Will greenhouse gas-induced warming over the
next 50 years lead to higher frequency and greater intensity of hurricanes? Tellus A.
48(1), 57-73. doi:10.1034/j.1600-0870.1996.00004.x.
Benson, C.S. 1982. Reassessment of winter precipitation on Alaska's Arctic Slope and
measurements on the flux of wind blown snow. Geophysical Institute, University of Alaska
Fairbanks.
Berthier, E., E. Schiefer, G.K.C. Clarke, B. Menounos and F. Remy. 2010. Contribution of
Alaskan glaciers to sea-level rise derived from satellite imagery. Nature Geoscience. 3(2),
92-95. doi:10.1038/ngeo737.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 21 February 2014 Draft
Bhatia, M.P., E.B. Kujawinski, S.B. Das, C.F. Breier, P.B. Henderson and M.A. Charette. 2013.
Greenland meltwater as a significant and potentially bioavailable source of iron to the
ocean. Nature Geoscience. 6(4) 274-278. doi:10.1038/ngeo1746.
Bjornsson, H. 2003. Subglacial lakes and jokulhlaups in Iceland. Global and Planetary Change.
35(3-4) 255 - 271. doi:http://dx.doi.org/10.1016/S0921-8181(02)00130-3.
Black, R.F. 1954. Precipitation at Barrow, Alaska, greater than recorded. Transactions,
American Geophysical Union. 35(2) 203-207. doi:10.1029/TR035i002p00203.
Bowling, S.A.. 1982. Climatic fluctuations and water yield from glacierized basins in Alaska. In
Harrison, W. and R. Consultants (eds.), Task 3 – Hydrology 1982 Susitna Basin glacier
studies. p. 22. Alaska Power Authority, Susitna Hydroelectric Project.
Braun, L.N., M. Weber and M. Schulz. 2000. Consequences of climate change for runoff from
Alpine regions. Annals of Glaciology. 31(1) 19-25. doi:10.3189/172756400781820165.
Callegary, J.B., C.P. Kikuchi, J.C. Koch, M.R. Lilly and S.A. Leake. 2013. Review:
Groundwater in Alaska (USA). Hydrogeology Journal. 21(1) 25-39. doi:10.1007/s10040-
012-0940-5.
Casassa, G., P. Lopez, B. Pouyaud and F. Escobar. 2009. Detection of changes in glacial run-off
in alpine basins: examples from North America, the Alps, central Asia and the Andes.
Hydrological Processes. 23(1), 31-41. doi:10.1002/hyp.7194.
Cederstrom, D.J.. 1963. Ground-water resources of the Fairbanks area, Alaska. United States
Goverment Printing Office.
Chen, J. and A. Ohmura. 1990. On the influence of Alpine glaciers on runoff. In Lang, H. and A.
Musy (eds.), Hydrology in Mountainous Regions I Hydrological Measurements, The
Water Cycle Lausanne Symposia. International Association of Hydrological Sciences
Publication. Vol. 193. p. 117-125. IAHS Press. Oxfordshire, UK.
Chow, V.T., D.R. Maidment and L.W. Mays. 1988. Applied hydrology. Tata McGraw-Hill
Education.
Clarke, T.S., D. Johnson and W.D. Harrison. 1985. Glacier runoff in the upper Susitna and
MacLaren river basins, Alaska. In Dwight, L.P. (eds.), Resolving Alaska's water resources
conflicts proceedings. Vol. 9D-111. Report No. IWR-108. University of Alaska Fairbanks.
Fairbanks, Alaska.
Cogley, J., R. Hock, L. Rasmussen, A. Arendt, A. Bauder, R. Braithwaite, P. Jansson, G. Kaser,
M. Moller, L. Nicholson and others. 2011. Glossary of glacier mass balance and related
terms. IHP-VII technical documents in hydrology. Vol. 86. No. IACS Contribution No. 2.
Comeau, L.E.L., A. Pietroniro and M.N. Demuth. 2009. Glacier contribution to the North and
South Saskatchewan Rivers. Hydrological Processes. 23(18) 2640-2653.
doi:10.1002/hyp.7409.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 22 February 2014 Draft
Curran, J.H. 2012. Streamflow Record Extension for Selected Streams in the Susitna River
Basin, Alaska. Scientific Investigations Report. No. 2012–5210. U.S. Department of the
Interior, U.S. Geological Survey.
Daanen, R.P., D. Misra, H. Epstein, D. Walker and V. Romanovsky. 2008. Simulating nonsorted
circle development in arctic tundra ecosystems. Journal of Geophysical Research:
Biogeosciences. 113(G03S06), doi:10.1029/2008JG000682.
Dingman, S.L., H. Samide, D. Saboe, M. Lynch and C. Slaughter. 1971. Hydrologic
reconnaissance of the Delta River and its drainage basin, Alaska. CRREL Report. No. RR-
262. U.S. Army Cold Regions Research and Engineering Laboratory. Dingman, S.L. and
F.R. Koutz. 1974. Relations among vegetation, permafrost, and potential insolation in
central Alaska. Arctic and Alpine Research. 6(1), 37-47.
Dingman, S.L. and F.R. Koutz. 1974. Relations among vegetation, permafrost, and potential
insolation in central Alaska. Arctic and Alpine Research. 6(1), 37-47.
Escher-Vetter, H. 2000. Modelling meltwater production with a distributed energy balance
method and runoff using a linear reservoir approach-Results from Vernagtferner, Oetztal
Alps, for the ablation. Zeitschrift fur Gletscherkunde und Glazialgeologie. 36 119-150.
Escher-Vetter, H. and O. Reinwarth. 1994. Two decades of runoff measurements (1974 to 1993)
at the Pegelstation Vernagtback/Oetztal Alps. Zeitschrift fur Gletscherkunde und
Glazialgeologie. 30 53-98.
Fleming, S.W. and G.K. Clarke. 2003. Glacial control of water resource and related
environmental responses to climatic warming: empirical analysis using historical
streamflow data from northwestern Canada. Canadian Water Resources Journal. 28(1),
69-86. doi:10.4296/cwrj2801069.
Flowers, G.E. and G.K.C. Clarke. 2002. A multicomponent coupled model of glacier hydrology
1. Theory and synthetic examples. Journal of Geophysical Research: Solid Earth.
107(B11), ECV 9-1-ECV 9-17. doi:10.1029/2001JB001122.
Ford, J. and B.L. Bedford. 1987. The hydrology of Alaskan wetlands, USA: a review. Arctic and
Alpine Research. 19(3) 209-229.
Fountain, A.G. and W.V. Tangborn. 1985. The Effect of Glaciers on Streamflow Variations.
Water Resources Research. 21(4), 579-586. doi:10.1029/WR021i004p00579.
Gardner, A.S., G. Moholdt, J.G. Cogley, B. Wouters, A.A. Arendt, J. Wahr, E. Berthier, R.
Hock, W.T. Pfeffer, G. Kaser, S.R.M. Ligtenberg, T. Bolch, M.J. Sharp, J.O. Hagen, M.R.
van den Broeke and F. Paul. 2013. A Reconciled Estimate of Glacier Contributions to Sea
Level Rise: 2003 to 2009. Science. 340(6134), 852-857. doi:10.1126/science.1234532.
Goodrich, L.E. 1982. The influence of snow cover on the ground thermal regime. Canadian
Geotechnical Journal. 19(4), 421-432. doi:10.1139/t82-047.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 23 February 2014 Draft
Hagg, W., L.N. Braun, M. Weber and M. Becht. 2006. Runoff modelling in glacierized Central
Asian catchments for present-day and future climate. Nordic Hydrology. 37(2), 93-105.
Hare, F.K. and J.E. Hay. 1971. Anomalies in the large-scale annual water balance over Northern
North America. Canadian Geographer. 15(2), 79-94. doi:10.1111/j.1541-
0064.1971.tb00145.x.
Harrison, W.D., B.T. Drage, S. Bredthauer, D. Johnson, C. Schoch and A.B. Follett. 1983.
Reconnaissance of the glaciers of the Susitna River basin in connection with proposed
hydroelectric development. Annals of Glaciology. 4, 99-104.
Harrison, W.D., D.H. Elsberg, K.A. Echelmeyer and R.M. Krimmel. 2001. On the
characterization of glacier response by a single time-scale. Journal of Glaciology.
47(159), 659-664. doi:10.3189/172756501781831837.
Hartmann, B. and G. Wendler. 2005. The significance of the 1976 pacific climate shift in the
climatology of Alaska. Journal of Climate. 18(22), 4824-4839. doi:10.1175/JCLI3532.1.
Haugen, R.K., C.W. Slaughter, K.E. Howe and S.L. Dingman. 1982. Hydrology and climatology
of the Caribou-Poker creeks research watershed, Alaska. CRREL Report. No. 82-26. U.S.
Army Cold Regions Research and Engineering Laboratory.
Hock, R. and C. Noetzli. 1997. Areal melt and discharge modelling of Storglaciéiren, Sweden.
Annals of Glaciology. 24 211-217.
Hock, R. 1999. A distributed temperature-index ice- and snowmelt model including potential
direct solar radiation. Journal of Glaciology. 45(149), 101-111.
Hock, R. 2003. Temperature index melt modelling in mountain areas. Journal of Hydrology.
282(1-4), 104-115. doi:http://dx.doi.org/10.1016/S0022-1694(03)00257-9.
Hock, R. 2005a. Glacier melt: a review of processes and their modelling. Progress in Physical
Geography. 29(3), 362-391.
Hock, R., P. Jansson and L. Braun. 2005b. Modelling the Response of Mountain Glacier
Discharge to Climate Warming. In Huber, U., H. Bugmann and M. Reasoner (eds.),
Global Change and Mountain Regions - An Overview of Current Knowledge. Vol. 23. p.
243-252. Springer, Netherlands.
Hodson, A., A.M. Anesio, M. Tranter, A. Fountain, M. Osborn, J. Priscu, J. Laybourn-Parry and
B. Sattler. 2008. Glacial ecosystems. Ecological Monographs. 78(1), 41-67.
Hood, E. and D. Scott. 2008. Riverine organic matter and nutrients in southeast Alaska affected
by glacial coverage. Nature Geoscience. 1 583-587. doi:10.1038/ngeo280.
Hood, E. and L. Berner. 2009. Effects of changing glacial coverage on the physical and
biogeochemical properties of coastal streams in southeastern Alaska. Journal of
Geophysical Research: Biogeosciences. 114(G3), doi:10.1029/2009JG000971.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 24 February 2014 Draft
Hood, E., J. Fellman, R.G. Spencer, P.J. Hernes, R. Edwards, D. D’Amore and D. Scott. 2009.
Glaciers as a source of ancient and labile organic matter to the marine environment.
Nature. 462(7276), 1044-1047. doi:10.1038/nature08580.
Hopkinson, C. and G.J. Young. 1998. The effect of glacier wastage on the flow of the Bow River
at Banff, Alberta 1951-1993. Hydrological Processes. 12(10-11), 1745-1762.
doi:10.1002/(SICI)1099-1085(199808/09)12:10/11<1745::AID-HYP692>3.0.CO;2-S.
Horton, P., B. Schaefli, A. Mezghani, B. Hingray and A. Musy. 2006. Assessment of climate-
change impacts on alpine discharge regimes with climate model uncertainty. Hydrological
Processes. 20(10) 2091-2109. doi:10.1002/hyp.6197.
Huss, M., D. Farinotti, A. Bauder and M. Funk. 2008. Modelling runoff from highly glacierized
alpine drainage basins in a changing climate. Hydrological Processes. 22(19), 3888-3902.
doi:10.1002/hyp.7055.
Huss, M., G. Jouvet, D. Farinotti and A. Bauder. 2010. Future high-mountain hydrology: a new
parameterization of glacier retreat. Hydrology and Earth System Sciences Discussions.
7(1), 345-387. doi:10.5194/hessd-7-345-2010.
Huss, M.. 2011. Present and future contribution of glacier storage change to runoff from
macroscale drainage basins in Europe. Water Resources Research. 47(7),
doi:10.1029/2010WR010299.
Huss, M., R. Hock, A. Bauder and M. Funk. 2012. Conventional versus reference-surface mass
balance. Journal of Glaciology. 38(208) 278-286. doi:10.3189/2012JoG11J216.
Immerzeel, W.. 2008. Historical trends and future predictions of climate variability in the
Brahmaputra basin. International Journal of Climatology. 28(2) 243-254.
doi:10.1002/joc.1528.
Immerzeel, W.W., F. Pellicciotti and M.F.P. Bierkens. 2013. Rising river flows throughout the
twenty-first century in two Himalayan glacierized watersheds. Nature Geoscience. 6 742-
745. doi:10.1038/ngeo1896.
Iwata, H., Y. Harazono and M. Ueyama. 2012. The role of permafrost in water exchange of a
black spruce forest in Interior Alaska. Agricultural and Forest Meteorology. 161 107-115.
doi:http://dx.doi.org/10.1016/j.agrformet.2012.03.017.
Jafarov, E.E., S.S. Marchenko and V.E. Romanovsky. 2012. Numerical modeling of permafrost
dynamics in Alaska using a high spatial resolution dataset. The Cryosphere Discussions. 6
89-124. doi:10.5194/tcd-6-89-2012.
Jansson, P., R. Hock and T. Schneider. 2003. The concept of glacier storage: a review. Journal of
Hydrology. 282(1-4), 116-129. doi:10.1016/S0022-1694(03)00258-0.
Jensen, H. and H. Lang. 1973. Forecasting discharge from a glaciated basin in the Swiss Alps. In
Role of Snow and Ice in Hydrology. International Association of Hydrological Sciences
Publication. Vol. 107(2). p. 1047-1057. IAHS Press. Oxfordshire, UK.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 25 February 2014 Draft
Johannesson, T., C.F. Raymond and E.D. Waddington. 1989. Time-scale adjustments of glaciers
to changes in mass balance. Journal of Glaciology. 35, 355-369.
Jorgenson, M., C.H. Racine, J.C. Walters and T.E. Osterkamp. 2001. Permafrost degradation and
ecological changes associated with a warming climate in Central Alaska. Climatic
Change. 48(4), 551-579. doi:10.1023/A:1005667424292.
Jorgenson, M.T., K. Yoshikawa, M. Kanevskiy, Y. Shur, V. Romanovsky, S. Marchenko, G.
Grosse, J. Brown and B. Jones. 2008. Permafrost characteristics of Alaska. Institute of
Northern Engineering, University of Alaska Fairbanks.
Juen, I., G. Kaser and C. Georges. 2007. Modelling observed and future runoff from a
glacierized tropical catchment (Cordillera Blanca, Peru). Global and Planetary Change.
59(1-4), 37 - 48. doi:http://dx.doi.org/10.1016/j.gloplacha.2006.11.038.
Kade, A., V.E. Romanovsky and D.A. Walker. 2006. The n-factor of nonsorted circles along a
climate gradient in Arctic Alaska. Permafrost and Periglacial Processes. 17(4) 279-289.
doi:10.1002/ppp.563.
Kalnay, E., M. Kanamitsu, R. Kistler, W. Collins, D. Deaven, L. Gandin, M. Iredell, S. Saha, G.
White, J. Woollen, Y. Zhu, A. Leetmaa, R. Reynolds, M. Chelliah, W. Ebisuzaki, W.
Higgins, J. Janowiak, K.C. Mo, C. Ropelewski, J. Wang, R. Jenne and D. Joseph. 1996.
The NCEP/NCAR 40-Year Reanalysis Project. Bulletin of the American Meteorological
Society. 77(3), 437-471. doi:10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2.
Kane, D. and C. Slaughter. 1973. Recharge of a central Alaska lake by sub-permafrost
groundwater. In Permafrost-North American Contribution to Second International
Conference on Permafrost, Yakutsk, Siberia, July 13-18. p. 458-462. National Academy of
Sciences. Washington, D.C.
Kane, D. and J. Stein. 1983a. Field evidence of groundwater recharge in interior Alaska. In,
Fourth international conference on permafrost Fairbanks Alaska, July 17-22, final
proceedings. Vol. 2. p. 572-577. National Academy Press. Washington, D.C.
Kane, D.L. and J. Stein. 1983b. Water movement into seasonally frozen soils. Water Resources
Research. 19(6), 1547-1557. doi:10.1029/WR019i006p01547.
Karl, T.R., J.M. Melillo and T.C. Peterson (eds.). 2009. Global climate change impacts in the
United States. Cambridge University Press.
Kaser, G., M. Grosshauser and B. Marzeion. 2010. Contribution potential of glaciers to water
availability in different climate regimes. Proceedings of the National Academy of Sciences
of the United States of America. 107(47) 20223-20227. doi:10.1073/pnas.1008162107.
Kaufman, D.S., D.P. Schneider, N.P. McKay, C.M. Ammann, R.S. Bradley, K.R. Briffa, G.H.
Miller, B.L. Otto-Bliesner, J.T. Overpeck, B.M. Vinther and A.L. 2k Project Members.
2009. Recent Warming Reverses Long-Term Arctic Cooling. Science. 325(5945), 1236-
1239. doi:10.1126/science.1173983.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 26 February 2014 Draft
Kobierska, F., T. Jonas, M. Zappa, M. Bavay, J. Magnusson and S.M. Bernasconi. 2013. Future
runoff from a partly glacierized watershed in Central Switzerland: A two-model approach.
Advances in Water Resources. 55(0) 204-214.
doi:http://dx.doi.org/10.1016/j.advwatres.2012.07.024.
Koboltschnig, G.R., W. Schoner, M. Zappa, C. Kroisleitner and H. Holzmann. 2008. Runoff
modelling of the glacierized Alpine Upper Salzach basin (Austria): multi-criteria result
validation. Hydrological Processes. 22(19), 3950-3964. doi:10.1002/hyp.7112.
Kyle, R.E., T.P. Brabets and others. 2001. Water temperature of streams in the Cook Inlet basin,
Alaska, and implications of climate change. U.S. Geological Survey Water-Resources
Investigation Report. No. 01-4109. U.S. Department of the Interior, U.S. Geological
Survey.
Lang, H. 1968. Relations between glacier runoff and meteorological factors observed on and
outside the glacier. In Snow and Ice. Reports and Discussions. International Association of
Hydrological Sciences Publication. No. 79. p. 439-439. IAHS Press. Oxfordshire, UK.
Lang, H. 1986. Forecasting meltwater runoff from snow-covered areas and from glacier basins.
In Kraijenhoff DA; Moll, J. (eds.), River flow modelling and forecasting. p. 99-127.
Springer.
Larsen, C.F., R.J. Motyka, A.A. Arendt, K.A. Echelmeyer and P.E. Geissler. 2007. Glacier
changes in southeast Alaska and northwest British Columbia and contribution to sea level
rise. Journal of Geophysical Research: Earth Surface. 112(F1),
doi:10.1029/2006JF000586.
Liston, G.E. and M. Sturm. 2002. Winter Precipitation Patterns in Arctic Alaska Determined
from a Blowing-Snow Model and Snow-Depth Observations. Journal of
Hydrometeorology. 3(6), 646-659. doi:10.1175/1525-
7541(2002)003<0646:WPPIAA>2.0.CO;2.
Lliboutry, L., B. Morales Arnao, A. Pautre and B. Schneider. 1977. Glaciological problems set
by the control of dangerous lakes in Cordillera Blanca, Peru. Journal of Glaciology.
18(79) 239-290.
Lynch, A.H., D.L. McGinnis and D.A. Bailey. 1998. Snow-albedo feedback and the spring
transition in a regional climate system model: Influence of land surface model. Journal of
Geophysical Research: Atmospheres. 103(D22) 29037-29049. doi:10.1029/98JD00790.
MacDougall, A.H., B.A. Wheler and G.E. Flowers. 2011. A preliminary assessment of glacier
melt-model parameter sensitivity and transferability in a dry subarctic environment. The
Cryosphere. 5 1011-1028. doi:10.5194/tc-5-1011-2011.
MacKay, D.K., S. Fogarasi and M. Spitzer. 1973. Documentation of an extreme summers storm
in the Mackenzie Mountains, N.W.T. In on Northern Oil Development, N.P.T.F. (eds.),
Hydrologic Aspects of Norhern Pipeline Development - A Series of 16 Reports. Vol. 73(3).
p. 191-222. Water Resources Branch. Ottawa, Canada.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 27 February 2014 Draft
Mark, B.G. and J.M. Mckenzie. 2007. Tracing Increasing Tropical Andean Glacier Melt with
Stable Isotopes in Water. Environmental Science & Technology. 41(20), 6955-6960.
doi:10.1021/es071099d.
Mark, B.G. and G.O. Seltzer. 2003. Tropical glacier meltwater contribution to stream discharge:
a case study in the Cordillera Blanca, Peru. Journal of Glaciology. 49(165) 271-281.
doi:10.3189/172756503781830746.
Meier, M. and W. Tangborn. 1961. Distinctive characteristics of glacier runoff. U.S. Geological
Survey Professional Paper. Vol. 424(B). U.S. Department of the Interior, U.S. Geological
Survey. Milner, A.M., E.E. Knudsen, C. Soiseth, A.L. Robertson, D. Schell, I.T. Phillips
and K. Magnusson. 2000. Colonization and development of stream communities across a
200-year gradient in Glacier Bay National Park, Alaska, U.S.A. Canadian Journal of
Fisheries and Aquatic Sciences. 57(11) 2319-2335. doi:10.1139/f00-212.
Milner, A.M., E.E. Knudsen, C. Soiseth, A.L. Robertson, D. Schell, I.T. Phillips and K.
Magnusson. 2000. Colonization and development of stream communities across a 200-
year gradient in Glacier Bay National Park, Alaska, U.S.A. Canadian Journal of
Fisheries and Aquatic Sciences. 57(11), 2319-2335. doi:10.1139/f00-212.
Molnia, B.F.. 2008. Glaciers of Alaska. U.S. Geological Survey Professional Paper. No. 1386K.
U.S. Department of the Interior, U.S. Geological Survey.
Neal, E., M.T. Walter and C. Coffeen. 2002. Linking the pacific decadal oscillation to seasonal
stream discharge patterns in Southeast Alaska . Journal of Hydrology . 263(1-4), 188-197.
doi:http://dx.doi.org/10.1016/S0022-1694(02)00058-6.
Neal, E.G., E. Hood and K. Smikrud. 2010. Contribution of glacier runoff to freshwater
discharge into the Gulf of Alaska. Geophysical Research Letters. 37(6),
doi:10.1029/2010GL042385.
Osterkamp, T.E. 2005. The recent warming of permafrost in Alaska . Global and Planetary
Change . 49(3-4), 187-202. doi:http://dx.doi.org/10.1016/j.gloplacha.2005.09.001.
Osterkamp, T.E. 2007. Causes of warming and thawing permafrost in Alaska. Eos, Transactions
American Geophysical Union. 88(48), 522-523. doi:10.1029/2007EO480002.
Osterkamp, T.E. and V.E. Romanovsky. 1999. Evidence for warming and thawing of
discontinuous permafrost in Alaska. Permafrost and Periglacial Processes. 10 17-37.
doi:10.1002/(SICI)1099-1530(199901/03)10:1<17::AID-PPP303>3.0.CO;2-4.
Ostrem, G. 1973. Runoff forecasts for highly glacierized basins. In Role of snow and ice in
hydrology. International Association of Hydrological Sciences Publication. Vol. 107(2). p.
1111-1132. IAHS Press. Oxfordshire, UK.
Overland, J., J. Key, B.M. Kim, S.J. Kim, Y. Liu, J. Walsh, M. Wang and U. Bhatt. 2012. Air
temperature, atmospheric circulation and clouds. In Arctic Report Card 2012.
http://www.arctic.noaa.gov/reportcard/temperature_clouds.html.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 28 February 2014 Draft
Overpeck, J., K. Hughen, D. Hardy, R. Bradley, R. Case, M. Douglas, B. Finney, K. Gajewski,
G. Jacoby, A. Jennings, S. Lamoureux, A. Lasca, G. MacDonald, J. Moore, M. Retelle, S.
Smith, A. Wolfe and G. Zielinski. 1997. Arctic Environmental Change of the Last Four
Centuries. Science. 278(5341), 1251-1256. doi:10.1126/science.278.5341.1251.
Patrick J.H. and P. Black. 1968. Potential evapotranspiration and climate in Alaska by
Thornthwaites classification. U.S. Department of Agriculture Forest Service Research
Paper. No. PNW-71. Institute of Northern Forestry.
Pellicciotti, F., B. Brock, U. Strasser, P. Burlando, M. Funk and J. Corripio. 2005. An enhanced
temperature-index glacier melt model including the shortwave radiation balance:
development and testing for Haut Glacier d'Arolla, Switzerland. Journal of Glaciology.
51(175), 573-587. doi:10.3189/172756505781829124.
Pfeffer, T., A.A. Arendt, A. Bliss, T. Bolch, J.G. Cogley, A.S. Gardner, J.O. Hagen, R. Hock, G.
Kaser, C. Kienholz, E.S. Miles, G. Moholdt, N. Moelg, F. Paul, V. Radi, P. Rastner, B.H.
Raup, J. Rich, M.J. Sharp, and the Randolph Consortium. The Randolph Glacier
Inventory: a globally complete inventory of glaciers. Journal of Glaciology, submitted.
Pouyaud, B., M. Zapata, J. Yerren, J. Gomez, G. Rosas, W. Suarez and P. Ribstein. 2005. On the
future of the water resources from glacier melting in the Cordillera Blanca, Peru.
Hydrological Sciences Journal= Journal des Sciences Hydrologiques. 50(6), 999-1022.
doi:10.1623/hysj.2005.50.6.999.
Quick, M. and A. Pipes. 1977. UBS Watershed Model. Hydrological Sciences Journal. 22(1),
153-161.
R&M Consultants Inc, and W.D. Harrison. 1981. Task 3 – Hydrology glacier studies, Alaska
Power Authority, Susitna Hydroelectric Project. Report for Acres American Inc., Buffalo,
NY.
R&M Consultants Inc. (1982). Susitna Hydroelectric Project, 1982 Field Data, Collection and
Processing, Supplement 1. Report for Acres American Inc., Buffalo, NY.
Racine, C.H. and J.C. Walters. 1994. Groundwater-discharge fens in the Tanana Lowlands,
interior Alaska, USA. Arctic and Alpine Research. 26(4), 418-426.
Radic, V. and R. Hock. 2011. Regionally differentiated contribution of mountain glaciers and ice
caps to future sea-level rise. Nature Geoscience. 4(2), 91-94. doi:10.1038/NGEO1052.
Radic, V., A. Bliss, A. Beedlow, R. Hock, E. Miles and J. Cogley. 2013. Regional and global
projections of twenty-first century glacier mass changes in response to climate scenarios
from global climate models. Climate Dynamics. April 1-22. doi:10.1007/s00382-013-
1719-7.
Radic, V. and R. Hock. 2013. Glaciers in the Earth’s Hydrological Cycle: Assessments of
Glacier Mass and Runoff Changes on Global and Regional Scales. Surveys in Geophysics.
1-25. doi:10.1007/s10712-013-9262-y.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 29 February 2014 Draft
Rawlins, M.A., D.J. Nicolsky, K.C. McDonald and V.E. Romanovsky. 2013. Simulating soil
freeze/thaw dynamics with an improved pan-Arctic water balance model. Journal of
Advances in Modeling Earth Systems. 5, doi:10.1002/jame.20045.
Raymond, P.A., J. McClelland, R. Holmes, A. Zhulidov, K. Mull, B. Peterson, R. Striegl, G.
Aiken and T. Gurtovaya. 2007. Flux and age of dissolved organic carbon exported to the
Arctic Ocean: A carbon isotopic study of the five largest arctic rivers. Global
Biogeochemical Cycles. 21(4), doi:10.1029/2007GB002934.
Rees, H.G. and D.N. Collins. 2006. Regional differences in response of flow in glacier-fed
Himalayan rivers to climatic warming. Hydrological Processes. 20(10) 2157-2169.
doi:10.1002/hyp.6209.
Robinson, C.T., U. Uehlinger and M. Hieber. 2001. Spatio-temporal variation in
macroinvertebrate assemblages of glacial streams in the Swiss Alps. Freshwater Biology.
46(12), 1663-1672. doi:10.1046/j.1365-2427.2001.00851.x.
Romanovsky, V.E., S.L. Smith and H.H. Christiansen. 2010. Permafrost thermal state in the
polar Northern Hemisphere during the international polar year 2007-2009: a synthesis.
Permafrost and Periglacial Processes. 21(2), 106-116. doi:10.1002/ppp.689.
Rothlisberger, H. and H. Lang. 1987. Glacial hydrology. In Gurnell, A.M. and M.J. Clark (eds.),
Glacio-Fluvial Sediment Transfer: An Alpine Perspective. p. 207-284. John Wiley &
Sons, Ltd. New York, USA.
Sharp, M. and G. Wolken. 2011. Arctic Glaciers and ice caps (outside Greenland). In Blunden,
J., D.S. Arndt and M. Baringer (eds.), State of the Climate in 2010. Bulletin of the
American Meteorological Society. Vol. 92(6). p. S155–S156.
Shulski, M. and G. Wendler. 2007. The climate of Alaska. University of Alaska Press.
Shur, Y.L. and M.T. Jorgenson. 2007. Patterns of permafrost formation and degradation in
relation to climate and ecosystems. Permafrost and Periglacial Processes. 18(1), 7-19.
doi:10.1002/ppp.582.
Slaughter, C.W., J.W. Hilgert and E.H. Culp. 1983. Summer streamflow and sediment yield from
discontinuous permafrost headwater catchments. In, Fourth international conference on
permafrost Fairbanks Alaska, July 17-22, final proceedings. Vol. 2. p. 1172-1177.
National Academy Press. Washington, D.C.
Slaughter, C.W. and D.L. Kane. 1979. Hydrologic role of shallow organic soils in cold climates.
In, Canadian hydrology symposium 79 - cold climate hydrology proceedings. Report No.
17834. p. 380-389. Vancouver, B.C., Canada.
Stahl, K. and R.D. Moore. 2006. Influence of watershed glacier coverage on summer streamflow
in British Columbia, Canada. Water Resources Research. 42(6),
doi:10.1029/2006WR005022.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 30 February 2014 Draft
Stahl, K., R.D. Moore, J.M. Shea, D. Hutchinson and A.J. Cannon. 2008. Coupled modelling of
glacier and streamflow response to future climate scenarios. Water Resources Research.
44(2), doi:10.1029/2007WR005956.
Stahl, K., H. Hisdal, J. Hannaford, L. Tallaksen, H.v. Lanen, E. Sauquet, S. Demuth, M.
Fendekova and J. Jódar. 2010. Streamflow trends in Europe: evidence from a dataset of
near-natural catchments. Hydrology and Earth System Sciences Discussions. 7(4), 5769-
5804.
Suarez, W., P. Chevallier, B. Pouyayd and P. Lopez. 2008. Modelling the water balance in the
glacierized Paron Lake basin (White Cordillera, Peru). Hydrological Sciences Journal.
53(1) 266-277. doi:10.1623/hysj.53.1.266.
Tangborn, W.V. 1984. Prediction of glacier derived runoff for hydroelectric development.
Geografiska Annaler. 66(A) 257-265.
VanLooy, J., R. Forster and A. Ford. 2006. Accelerating thinning of Kenai Peninsula glaciers,
Alaska. Geophysical Research Letters. 33(21), doi:10.1029/2006GL028060.
Vuille, M., B. Francou, P. Wagnon, I. Juen, G. Kaser, B.G. Mark and R.S. Bradley. 2008.
Climate change and tropical Andean glaciers: Past, present and future . Earth-Science
Reviews. 89(3-4), 79-96. doi:http://dx.doi.org/10.1016/j.earscirev.2008.04.002.
Walsh, J.E., W.L. Chapman, V. Romanovsky, J.H. Christensen and M. Stendel. 2008. Global
climate model performance over Alaska and Greenland. Journal of Climate. 21 6156-
6174. doi:10.1175/2008JCLI2163.1.
Weber, M., L. Braun, W. Mauser and M. Prasch. 2010. Contribution of rain, snow-and icemelt in
the upper Danube discharge today and in the future. Geografia Fisica e Dinammica
Quaternaria. 33(2) 221-230.
Wilcox, D.E. 1980. Geohydrology of the Delta-Clearwater Area, Alaska. U.S. Geological Survey
Water-Resources Investigation Report. No. 80-92. U.S. Department of the Interior, U.S.
Geological Survey.
Williams, J.R. 1970. Ground water in the permafrost regions of Alaska. U.S. Geological Survey
Professional Paper. No. 696. U.S. Department of the Interior, U.S. Geological Survey.
Willis, I.C., N.S. Arnold and B.W. Brock. 2002. Effect of snowpack removal on energy balance,
melt and runoff in a small supraglacial catchment. Hydrological Processes. 16(14) 2721-
2749. doi:10.1002/hyp.1067.
Wolken, J.M., T.N. Hollingsworth, T.S. Rupp, F.S. Chapin III, S.F. Trainor, T.M. Barrett, P.F.
Sullivan, A.D. McGuire, E.S. Euskirchen, P.E. Hennon and others. 2011. Evidence and
implications of recent and projected climate change in Alaska's forest ecosystems.
Ecosphere. 2(11), 1-35. doi:10.1890/ES11-00288.1.
Wolken, G., M. Sharp, M.L. Geai, D. Burgess, A. Arent and B. Wouters. 2013. Arctic Glaciers
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 31 February 2014 Draft
and ice caps (outside Greenland). In Blunden, J. and D.S. Arndt (eds.), State of the
Climate in 2012. Bulletin of the American Meteorological Society. Vol. 94(8). p. S119–
S121.
Yao, T., J. Pu, A. Lu, Y. Wang and W. Yu. 2007. Recent Glacial Retreat and Its Impact on
Hydrological Processes on the Tibetan Plateau, China, and Surrounding Regions. Arctic,
Antarctic, and Alpine Research. 39(4), 642-650. doi: 10.1657/1523-0430(07-
510)[YAO]2.0.CO;2.
Zhang, J., U.S. Bhatt, W.V. Tangborn and C.S. Lingle. 2007a. Climate downscaling for
estimating glacier mass balances in northwestern North America: Validation with a USGS
benchmark glacier. Geophysical Research Letters. 34(21), doi:10.1029/2007GL031139.
Zhang, J., U.S. Bhatt, W.V. Tangborn and C.S. Lingle. 2007b. Response of glaciers in
northwestern North America to future climate change: an atmosphere/glacier hierarchical
modeling approach. Annals of Glaciology. 46(1) 283-290.
doi:10.3189/172756407782871378.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 32 February 2014 Draft
10. TABLES
Table 4.1-1. Reported studies of regional-scale glacier mass changes in Alaska (including the adjacent glaciers in northwestern Canada).
Assuming, where necessary, an ice/firn/snow density of 900 kg m-3 and rounding to whole years.
* “32,900km2, about 40% of the area” yields 82,250. So here we assume the area is equal to Arendt et al. 2013.
** Area not defined in the reference.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 33 February 2014 Draft
Table 4.2.4.2-1. Summer, winter and annual mass balances in meters water equivalent for the four major glaciers in the
Susitna River Basin.
*Assumed annual balance at East Fork Glacier was -0.3 m in 1981. Data provided from Clarke et al. (1985).
Glacier Name
Mass Balance Measurements for Susitna River Basin Glaciers (m w.eq.)
Summer Balance bs May 15 to September 30
Winter Balance bw October 1 to May 14
Annual Balance ba
October 1 to September 30
1981 1982 1983 1981 1982 1983 1981 1982 1983
West Fork -0.87 -1.02 -0.81 0.86 0.78 0.93 -0.01 -0.24 0.12
Susitna -1.03 -0.87 -0.38 0.76 0.65 0.78 -0.3 -0.22 0.4
East Fork -- -0.97 -0.69 -- 0.77 0.78 --* -0.2 0.09
Maclaren -0.52 -1 -0.7 0.83 1.44 1.07 0.3 0.14 0.37
Average -0.85 -0.96 -0.63 0.8 0.81 0.89 0.05 -0.15 0.26
Table 7.3. Total runoff measured at several stream gauges and the estimated runoff contributions from the glacierized
area in the Susitna River Basin.
All data and averages are for the period 1981 to 1983 and are taken from Clarke et al. (1985). aThe total flow above
the Denali Highway is compiled from the Maclaren River and Susitna River at Denali Highway stream gauges. bThe
total glacier runoff contribution does not include runoff from glaciers in the Talkeetna Mountains at the Susitna
River at Gold Creek stream gauge. cThe glacierized area is not known accurately because the meltwater contribution
from Eureka Glacier changes from the Delta River to the Susitna River at unknown intervals (R&M Consultants,
Inc. 1981).
Stream Gauge
Name
Runoff in Susitna River Basin
Average Total
Runoff at Stream
Gauge (m/yr)
Total Glacier Runoff
(m/yr)
(snow, firn, ice, rain)
Glacier Runoff
Component % of
Total Runoffc
Glacierized Area
(km2)c
1981 - 1983 1981 1982 1983 1981 - 1983 1981 - 1983
Maclaren River at
Denali Hwy 1.22 1.3 1.4 1.2 24% 160c
Susitna River at
Denali Hwy 1.07 1.7 1.7 1.4 38% 628
Total flow above
Denali Hwya 1.1 -- -- -- 34% 790c
Susitna River at
Gold Creekb 0.59 1.6 1.6 1.4 13% 790c
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 34 February 2014 Draft
Table 7.2.2-1. Meteorological stations used to record climatic data from 1980 to 1984 in the Susitna River Basin by R&M
Consultants, Inc.
Climate
Station
Name
General
Region
Land Cover
Classification
Elevation
(m) Coordinates Period of
Record
Denali Upper Susitna
Basin Shrubland 828 63° 05' 24" N
147° 28' 12" W
July 1980 -
Dec 1984
Kosina Creek Upper Susitna
Basin Shrubland 792 62° 41' 24" N
147° 58' 12" W
Aug 1980 -
Dec 1984
Susinta
Glacier
Alaska Range
Mountains Barren Land 1433 63° 31' 48" N
146° 53' 24" W
July 1980 -
Dec 1984
Watana At Proposed
Dam Site Shrubland 701 62° 50' 24" N
148° 30' 36" W
Apr 1980 -
Dec 1984
Devil Canyon Downstream of
Dam Site
Coniferous
Forest 457 62° 48' 50" N
149° 18' 50" W
Apr 1980 -
Dec 1984
Sherman Downstream of
Dam Site Mixed Forest 183 62° 42' 10" N
149° 49' 52" W
Oct 1981 -
Dec 1984
Table 7.2.2-2. Individual sources for recovered climate data from the Susitna basin during the period 1980-1984.
Denali
Station
Source
Year 1980 – 1981 R&M Consultants, Inc. (1982), Susitna Hydroelectric Project, Processed Climatic Data, Volume 2,
Denali Station. Prepared for Acres American Inc. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol2/hydropower/APA_DOC_no._200.pdf.
Year 1981 – 1982 R&M Consultants, Inc. (1982), Susitna Hydroelectric Project 1982 Field Data, Collection and
Processing, Supplement 1. Prepared for Acres American Inc. Susitna Hydroelectirc Project, Federal
Energy Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/2/APA211.pdf.
Year 1982 – 1983 R&M Consultants, Inc. (1984), Processed Climatic Data October 1982 - September 1983, Vol. 2,
Denali Station. Final Report, Document No. 1089. Under Contract to Hazra-Ebasco Sustina Joint
Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/10/APA1089.pdf.
Year 1983 – 1984 R&M Consultants, Inc. (1985), Processed Climatic Data October 1983 - December 1984, Vol. 2,
Denali Station. Final Report, Document No. 2768. Under Contracted to Hazra-Ebasco Sustina Joint
Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/27/APA2768.pdf.
Devil Canyon Station Source
Year 1980 – 1981 R&M Consultants, Inc. (1982), Susitna Hydroelectric Project, Processed Climatic Data, Volume 6,
Devil Canyon Station. Prepared for Acres American Inc. Susitna Hydroelectirc Project, Federal
Energy Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol2/hydropower/APA_DOC_no._208.pdf
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 35 February 2014 Draft
Year 1981 – 1982 R&M Consultants, Inc. (1982), Susitna Hydroelectric Project 1982 Field Data, Collection and
Processing, Supplement 1. Prepared for Acres American Inc. Susitna Hydroelectirc Project, Federal
Energy Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/2/APA211.pdf.
Year 1982 – 1983 R&M Consultants, Inc. (1984), Processed Climatic Data October 1982 - September 1983, Vol. V,
Devil Canyon Station. Final Report, Document No. 1092. Under Contract to Hazra-Ebasco Sustina
Joint Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/10/APA1092.pdf.
Year 1983 – 1984 R&M Consultants, Inc. (1985), Processed Climatic Data October 1983 - December 1984, Vol. 5,
Devil Canyon Station. Final Report, Document No. 2771. Under Contracted to Hazra-Ebasco Sustina
Joint Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/27/APA2771.pdf.
Kosina Creek Station Source
Year 1980 – 1981 R&M Consultants, Inc. (1982), Susitna Hydroelectric Project 1982 Field Data, Collection and
Processing, Supplement 1. Prepared for Acres American Inc. Susitna Hydroelectirc Project, Federal
Energy Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol2/hydropower/APA_DOC_no._204.pdf.
Year 1981 – 1982 R&M Consultants, Inc. (1982), Susitna Hydroelectric Project 1982 Field Data, Collection and
Processing, Supplement 1. Prepared for Acres American Inc. Susitna Hydroelectirc Project, Federal
Energy Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/2/APA211.pdf.
Year 1982 – 1983 R&M Consultants, Inc. (1984), Processed Climatic Data October 1982 - September 1983, Vol. 3,
Kosina Creek Station. Final Report, Document No. 1090. Under Contract to Hazra-Ebasco Sustina
Joint Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/10/APA1090.pdf.
Year 1983 – 1984 R&M Consultants, Inc. (1985), Processed Climatic Data October 1983 - December 1984, Vol. 3,
Kosina Creek Station. Final Report, Document No. 2769. Under Contract to Hazra-Ebasco Sustina
Joint Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/27/APA2769.pdf.
Sherman
Station
Source
Year 1981 – 1982 R&M Consultants, Inc. (1982), Susitna Hydroelectric Project 1982 Field Data, Collection and
Processing, Supplement 1. Prepared for Acres American Inc. Susitna Hydroelectirc Project, Federal
Energy Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/2/APA211.pdf.
Year 1982 – 1983 R&M Consultants, Inc. (1984), Processed Climatic Data October 1982 - September 1983, Vol. 6,
Sherman Station. Final Report, Document No. 1093. Under Contract to Hazra-Ebasco Sustina Joint
Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/10/APA1093.pdf.
Year 1983 – 1984 R&M Consultants, Inc. (1985), Processed Climatic Data October 1983 - December 1984, Vol. 6,
Sherman Station. Final Report, Document No. 2772. Under Contract to Hazra-Ebasco Sustina Joint
Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/27/APA2772.pdf.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 36 February 2014 Draft
Susitna Glacier Station Source
Year 1980 – 1981 R&M Consultants, Inc. (1982), Susitna Hydroelectric Project, Processed Climatic Data Volume 5
Susitna Glacier Station. Prepared for Acres American Inc. Susitna Hydroelectirc Project, Federal
Energy Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol2/hydropower/APA_DOC_no._198.pdf.
Year 1981 – 1982 R&M Consultants, Inc. (1982), Susitna Hydroelectric Project 1982 Field Data, Collection and
Processing, Supplement 1. Prepared for Acres American Inc. Susitna Hydroelectirc Project, Federal
Energy Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/2/APA211.pdf.
Year 1982 – 1983 R&M Consultants, Inc. (1984), Processed Climatic Data October 1982 - September 1983, Vol. 1,
Susitna Glacier Station. Final Report, Document No. 1088. Under Contract to Hazra-Ebasco Sustina
Joint Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/10/APA1088.pdf.
Year 1983 – 1984 R&M Consultants, Inc. (1985), Processed Climatic Data October 1983 - December 1984, Vol. 1,
Susitna Glacier Station. Final Report, Document No. 2767. Under Contract to Hazra-Ebasco Sustina
Joint Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/27/APA2767.pdf.
Watana
Station
Source
Year 1980 – 1981 R&M Consultants, Inc. (1982), Susitna Hydroelectric Project, Processed Climatic Data, Volume 5,
Watana Station. Prepared for Acres American Inc. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol2/hydropower/APA_DOC_no._206.pdf.
Year 1981 – 1982 R&M Consultants, Inc. (1982), Susitna Hydroelectric Project 1982 Field Data, Collection and
Processing, Supplement 1. Prepared for Acres American Inc. Susitna Hydroelectirc Project, Federal
Energy Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/2/APA211.pdf.
Year 1982 – 1983 R&M Consultants, Inc. (1984), Processed Climatic Data October 1982 - September 1983, Vol. 4,
Watana Station. Final Report, Document No. 1091. Under Contract to Hazra-Ebasco Sustina Joint
Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/10/APA1091.pdf.
Year 1983 – 1984 R&M Consultants, Inc. (1985), Processed Climatic Data October 1983 - December 1984, Vol. 4,
Watana Station. Final Report, Document No. 2770. Under Contract to Hazra-Ebasco Sustina Joint
Venture. Prepared for Alaska Power Authority. Susitna Hydroelectirc Project, Federal Energy
Regulatory Commission, Project No. 7114.
Available at: http://www.arlis.org/docs/vol1/Susitna/27/APA2770.pdf.
Table 7.2.3-1. Overview of gridded Climate Products for Alaska.
Gridded Products Spatial
Resolution
Temporal
Resolution /
Period
covered
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 37 February 2014 Draft
OSU’s David Hill’s Monthly Temperature and
Precipitation grids for Alaska, British Columbia,
and Yukon
2 km Monthly /
1961 - 2009
University of British Columbia NARR downscaled
Temperature, Precipitation, and Solar grids (SE AK
and BC at present)
< 2 km Daily
SNAP Temperature and Precipitation historical
(CRU TS 3.1 1901-2009)
771 m / 2 km Monthly /
1901 - 2009
OSU’s PRISM (1971-2000) 800 m / 4 km Monthly /
1971 - 2000
NCEP Climate Forecast System Reanalysis (CFSR)
(1979-2010)
38 km – 2.5 deg Hourly, 6-
hourly, monthly
1979 - 2010
ECMEF ERA 40 Temperature and Precipitation
(1958-2002)
0.5 deg 1958 - 2002
ECMEF ERA Interim 0.5 deg 1979 – Present
NCEP and NCAR 2.5 deg 1948 – Present
NARR 32 km 1979 – Present
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 38 February 2014 Draft
11. FIGURES
Figure 2.1. Susitna Glacier and other unnamed glaciers contributing to Upper Susitna River drainage.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 39 February 2014 Draft
Figure 4.1-1. 100-year projections of glacier volume in Alaska using 14 Global Climate Models forced by the
RCP4.5 emission scenario.
Glaciers in Alaska are expected to lose 18-45% (multi-model mean 32%) of their initial volume (2003) by the end of
the century (Radic et al. 2013).
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 40 February 2014 Draft
Figure 4.2.2-1. Variations in glacier runoff and mass balance.
(a) Schematic seasonal variation of total glacier runoff, defined as all water exiting a glacier, and its components, E
is evaporation; (b) cumulative glacier mass balance in specific units (m w.e. year-1) showing a year with negative
annual balance (Radic and Hock in press).
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 41 February 2014 Draft
Figure 4.2.2-2. Schematic representation of the long-term effects glacier mass loss on: a) glacier volume; and
b) glacier runoff.
Note that runoff initially increases as melt is enhanced but then reaches a ‘turning point’ beyond which runoff
decreases as the glacier shrinks thus reducing the excess runoff from glacier storage (modified from Jansson et al.
2003).
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 42 February 2014 Draft
Figure 4.2.2-3. Initial effects of atmospheric warming on glacier runoff including feedback mechanisms
leading to further enhanced runoff totals and peak flows (Hock et al. 2005).
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 43 February 2014 Draft
Figure 4.2.3.3-1. Concept of linear reservoirs as applied to glaciers using one to three (c-a) different linear
reservoirs.
Reservoirs are coupled in parallel in (a-b), and in series in (d). Exact delineation of reservoirs varies between
studies. Q is outflow from the reservoirs (Hock et al. 2005b).
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 44 February 2014 Draft
Figure 4.2.4.2-1 Map of the upper Susitna basin, including the locations of historical meteorological, stream
gauge and glacier monitoring stations.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 45 February 2014 Draft
Figure 5-1. Permafrost distribution in the upper Susitna basin.
A majority of the area draining into the proposed dam is estimated to be underlain by discontinuous and continuous
permafrost (modified after Jorgenson et al. 2008). Maximum depth to the base of permafrost in the Maclaren River
junction with the Susitna River is about 200 m (Alaska District, Corps of Engineers 1975), while it is 40 m at
Gulkana, which is just outside the basin to the southeast (Geophysical Institute permafrost lab).
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 46 February 2014 Draft
Figure 7.2.1-1. Coverage of temperature and precipitation data at 33 Climate Stations in and in proximity of
the Upper Susitna Basin.
A black bar indicates that coverage exists.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 47 February 2014 Draft
Figure 7.2.1-2. Period of record for temperature measurements collected during the 1980s in the Susitna
basin.
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 48 February 2014 Draft
Figure 7.2.2-1. Air temperature in degrees Celsius at the six climate stations monitored from 1980 to 1984.
The hydrologic year is indicated by the dashed black vertical lines. The hydrologic year runs from September 30th to
October 1st of the following year.
10 01 04 07 10 01 04 07 10 01 04 07 10 01 04 07 10-40
-30
-20
-10
0
10
20
MonthsAir Temperature (°C)Air Temperature (°C) at Historic Climate Stations
WB 1981 WB 1982 WB 1983 WB 1984
Denali
Kosina Creek
Susitna Glacier
Watana
Devil Canyon
Sherman
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 49 February 2014 Draft
Figure 7.2.2-2. Recovered Snow Depth Measurements (1981 and 1982; source: R&M Consultants, Inc. 1982).
INITIAL STUDY REPORT GLACIER AND RUNOFF CHANGES STUDY (7.7)
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 50 February 2014 Draft
Figure 7.3-1. Comparisons of annual mean precipitation during 1994-2004 from the global reanalysis
(2.5ox2.5o), 30km and 10km downscaling (topography in black contour and precipitation in color) (Zhang et
al. 2007a).