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Susitna-Watana Hydroelectric Project Document
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Title:
Groundwater study, Study plan Section 7.5 : Final study plan
SuWa 200
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Alaska Energy Authority
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Final study plan
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Susitna-Watana Hydroelectric Project document number 200
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[Anchorage : Alaska Energy Authority, 2013]
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July 2013
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Study plan Section 7.5
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35 p.
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All reports in the Susitna-Watana Hydroelectric Project Document series include an ARLIS-
produced cover page and an ARLIS-assigned number for uniformity and citability. All reports
are posted online at http://www.arlis.org/resources/susitna-watana/
Susitna-Watana Hydroelectric Project
(FERC No. 14241)
Groundwater Study
Study Plan Section 7.5
Final Study Plan
Prepared for
Alaska Energy Authority
July 2013
FINAL STUDY PLAN GROUNDWATER STUDY 7.5
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 7.5-1 July 2013
7.5. Groundwater Study
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 Groundwater Study,
Section 7.5. RSP Section 7.5 focuses on providing an overall understanding of GW/SW
interactions at both the watershed- and local-scales.
On February 1, 2013, FERC staff issued its study determination (February 1 SPD) for 44 of the
58 studies, approving 31 studies as filed and 13 with modifications. On April 1, 2013 FERC
issued its study determination (April 1 SPD) for the remaining 14 studies; approving 1 study as
filed and 13 with modifications. RSP Section 7.5 was one of the 13 approved with
modifications. In its April 1 SPD, FERC recommended the following:
Evapotranspiration Model
- We recommend that AEA consult wie th the TWG on the construction of the necessary data
sets for the MODFLOW RIP-ET package, and file no later than June 30, 2013, the
following:.
1) A detailed description of the specific methods to be used to relate the data of Study
11.6 (riparian vegetation) to plant functional groups.
2) A detailed description of the specific methods to be used to relate the rooting depth
data from Study 8.6 (riparian instream flow) and the water level data from Study 7.5
(groundwater) to extinction and saturated extinction depths.
3) A detailed description of the specific methods to be used to estimate the shape of the
transpiration flux curves.
4) Documentation of consultation with the TWG, including how its comments were
addressed.
In addition FERC recommended AEA conduct a literature review include studies of
hydroelectric project effects on surface water/groundwater interactions in cold regions.
Consultation on the interrelated riparian vegetation, riparian instream flow and riparian
groundwater/surface water (GW/SW) study plans was accomplished with TWG representatives
in two meetings; held April 23, 2013 and June 6, 2013. Licensing participants were provided the
opportunity to address technical details and comments and concerns regarding the study’s
approaches and methods.
The Riparian Instream Flow, Groundwater, and Riparian Vegetation Studies FERC
Determination Response Technical Memorandum (Riparian/GW TM) summarizes details
concerning sampling design, proposed field protocols and analytical methodologies related to
FERC Determination requests. The document is organized to address details for each of the
three RSPs: Groundwater Study 7.5, Riparian Instream Flow Study 8.6, and Riparian Vegetation
Study 11.6. The Riparian/GW TM was filed with FERC on June 30, 2013. The Riparian/GW
TM addresses each of the four components of the above FERC recommendation. Information in
the Riparian/GW TM supersedes relevant details within this Final Study Plan.
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FERC Project No. 14241 Page 7.5-2 July 2013
7.5.1. General Description of the Proposed Study
Project construction and operation will affect Susitna River flows downstream of the proposed
dam; the degree of these effects will ultimately depend on final Project design and operations.
Project operations will cause seasonal, daily, and hourly changes in Susitna River flows
compared to existing conditions. The potential alteration in flows will influence downstream
resources/processes, including fish and aquatic biota and their habitats, channel form and
function including sediment transport, water quality, groundwater/surface water interactions
(GW/SW), ice dynamics, and riparian and wildlife communities (AEA 2011). The overall goal of
this study is to understand the effects of the Project on GW/SW interactions at multiple spatial
and temporal scales as they relate to aquatic and floodplain species in the Susitna River.
Additionally, one task is focused on evaluating the potential impacts to shallow groundwater
well users in the Susitna River corridor. The study is one part of a set of interdisciplinary
resource studies that are designed to evaluate the overall effects of Project operations. The
Groundwater Study is specifically linked with both the Riparian Instream Flow Study and the
Fish and Aquatics Instream Flow Study since the ecological functionality of riparian and aquatic
habitats can be directly influenced by GW/SW interactions. It is therefore important to
understand whether and the extent to which Project operations may influence those interactions,
and how those effects may impact riparian and aquatic habitats. The study will use existing
information and data, as well as new data collected during this and other studies to provide an
overall understanding of GW/SW interactions at both the watershed- and local-scales.
The overall objectives of this study are as follows:
1. Synthesize historical and contemporary groundwater data available for the Susitna River
groundwater and groundwater dependent aquatic and floodplain habitat, including that
from the 1980s and other studies including reviews of GW/SW interactions in cold
regions.
2. Use the available groundwater data to characterize large-scale geohydrologic process-
domains/terrain of the Susitna River (e.g., geology, topography, geomorphology, regional
aquifers, shallow groundwater aquifers, GW/SW interactions).
3. Assess the potential effects of Watana Dam/Reservoir on groundwater and groundwater-
influenced aquatic habitats in the vicinity of the proposed dam.
4. Work with other resource studies to map groundwater-influenced aquatic and floodplain
habitat (e.g., upwelling areas, springs, groundwater-dependent wetlands) within the
Middle River Segment of the Susitna River including within selected Focus Areas (see
Section 8.5.4.2.1.2).
5. Determine the GW/SW relationships of floodplain shallow alluvial aquifers within
selected Focus Areas as part of the Riparian Instream Flow Study (Section 8.6).
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6. Determine GW/SW relationships of upwelling/downwelling in relation to spawning,
incubation, and rearing habitat (particularly in the winter) within selected Focus Areas as
part of the Fish and Aquatics Instream Flow Study (Section 8.5).
7. Characterize water quality (e.g., temperature, dissolved oxygen [DO], conductivity) of
selected upwelling areas that provide biological cues for fish spawning and juvenile
rearing, in Focus Areas as part of the Fish and Aquatics Instream Flow Study (Section
8.5).
8. Characterize the winter flow in the Susitna River and how it relates to GW/SW
interactions.
9. Characterize the relationship between the Susitna River flow regime and shallow
groundwater users (e.g., domestic wells).
7.5.2. Existing Information and Need for Additional Information
Groundwater/surface water interactions in the Susitna River watershed have been studied at
different locations in the river and at different times. The lower Susitna River watershed is part
of the geologic Susitna Basin (Kirschner 1994) (Figure 7.5-1). This region has generally been
referred to as the lower Susitna River. The major physiographic regions of the Susitna watershed
are described in Wahrhaftig (1994) and Kenneson (1980a, 1980b), and include: a) the Alaska
Range on the northern portion of the watershed, which also forms the watershed boundary in the
headwaters of the watershed; b) the Talkeetna Mountains that cross the central portion of the
watershed and result in physiographic features such as Devils Canyon and Watana Canyon; and
c) the upper Matanuska Valley that covers the lower portion of the wat ershed and is bounded on
the downstream end by Cook Inlet. The watershed-scale geology covers a range of highly
metamorphic marine sedimentary formations, referred to as Flysch belts (Beikman 1994) (Figure
7.5-2). There are also younger volcanic deposits in the middle portion of the watershed. The
Susitna River flows out of the Talkeetna Mountains in the vicinity of Talkeetna, where it then
flows through the sedimentary Susitna Basin.
Hydropower-related studies of the Susitna River watershed during the 1980s included
observations and monitoring of GW/SW interactions. These studies focused on river habitats
such as side channels, side sloughs, and upland sloughs that were determined to be important fish
habitat. A large amount of physical hydrology data (e.g., stage-discharge relationships, main
stage versus upwelling discharge, piezometers), water quality data (e.g., temperature), aquatic
habitat, and other observations were reported for various study sites (see Section 8.5.2.1).
Since the 1980s, various wells have been drilled for domestic water supply, mining exploration,
oil and gas exploration, railroad operations, and other activities associated with resource
development or evaluations in the watershed.
The Groundwater Study is needed to first define the role that existing GW/SW interactions play
in the development and sustainability of riparian communities proximal to the Susitna River, and
how these interactions serve to create and maintain certain flow dependent biological cues (e.g.,
upwelling, downwelling, temperature moderation) used by salmonids for spawning, egg
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FERC Project No. 14241 Page 7.5-4 July 2013
incubation, and rearing. In addition, shallow groundwater wells used by residents (e.g., domestic)
may also be dependent on Susitna River GW/SW interactions.
The information developed in the Groundwater Study will be used to define and evaluate
existing GW/SW interactions as they relate to the ecology of riparian and aquatic habitats, and
then use that information for assessing how Project construction and operation may alter those
interactions and the corresponding riparian and aquatic habitats.
7.5.3. Study Area
The study area related to groundwater processes includes primarily the Middle River Segment of
the Susitna River that extends from RM 98.5 to RM 184, as well as portions of the Lower River
Segment associated with domestic wells, and the lowermost portion of the Upper River Segment
near the proposed dam site associated with potential groundwater changes relative to reservoir
elevation change. The groundwater investigations in the Middle River Segment will include
those designed to evaluate GW/SW interactions relative to riparian and aquatic habitats, as well
as GW/SW interactions on domestic wells. The study in the Middle River Segment will be
concentrated within a series of Focus Areas that have been identified for detailed investigation.
As noted in Section 8.5.4.2.1.2., the Focus Areas are intended to serve as specific geographic
areas of the river that will be the subject of intensive investigation by multiple resource
disciplines including Fish and Aquatics Instream Flow Study (Section 8.5), Riparian Instream
Flow Study (Section 8.6), Groundwater Study, Geomorphology studies (Sections 6.5 and 6.6),
Ice Processes Study (Section 7.6), and Water Quality stud ies (Sections 5.5 and 5.6). The Focus
Areas were selected during an inter-disciplinary resource meeting that involved a systematic
review of aerial imagery within each of the Geomorphic Reaches (MR-1 through MR-8) for the
entire Middle River Segment of the river (see Table 8.5-5 in Section 8.5 for a listing of nested
and tiered habitat mapping units, categories and definitions that are being used across resource
disciplines). Overall, ten potential Focus Areas have been identified, (see Table 8.5 -6 in Section
8.5) although GW/SW interactions will not be intensively studied at each of these ten Focus
Areas. Rather, the studies will be limited to those Focus Areas exhibiting GW/SW interactions
that relate to the ecology of riparian and/or aquatic habitats. These will be determined pending
further evaluation of each of the Focus Areas.
Determining how far downstream Project operational effects will extend will depend in part on
the results of the Open-water Flow Routing Model (see Section 8.5.4.3), which is scheduled to
be completed in Q1 2013 as well as results of the operations model (Section 8.5.4.3.2). The
results of the Open-water flow routing model completed in Q1 2013 will be used to determine
whether and the extent to which Project operations related to load-following as well as seasonal
flow changes occur within a section of the Lower River Segment that includes all of geomorphic
reach L1 and a portion of L2 (down to RM 75). Thus, an initial assessment of the downstream
extent of Project effects will be developed in Q1 2013 with input from the Technical Workgroup.
This assessment will include a review of information developed during the 1980s studies and
study efforts initiated in 2012, such as sediment transport (Section 6.5), habitat mapping
(Sections 6.5 and 9.9), operations modeling (Section 8.5.4.2.2), and the Mainstem Open-water
Flow Routing Model (Section 8.5.4.3). Nevertheless, the review of background information and
large-scale geohydrologic process-domains/terrain of the Susitna River covers all three segments
of the Susitna River. This overview is important for determining the boundary conditions
affecting groundwater flow conditions along the entire river corridor.
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FERC Project No. 14241 Page 7.5-5 July 2013
7.5.4. Study Methods
The Groundwater Study is divided into nine study components related to the study objectives
outlined above: (1) Existing Data Synthesis, (2) Geohydrologic Process-Domains and Terrain;
(3) Watana Dam/Reservoir, (4) Upwelling/Springs Broad-Scale Mapping, (5) Riparian
Vegetation Dependency on GW/SW Interactions, (6) Fish Habitat GW/SW Interactions, (7)
Water Quality in Selected Habitats, (8) Winter GW/SW Interactions, and (9) Shallow
Groundwater Users. Each of the components and its related study methods are explained further
in the following subsections. The methods described represent standard approaches for
summarizing data and assessing the physical/biological processes related to groundwater and
aquatic habitat. Many of the study components represent contributory elements of other resource
studies, for example the 4th component, Upwelling-Springs mapping is linked to both the Ice
Processes Study (Section 7.6), the Geomorphology Study (Section 6.5), the Water Quality Study
(Section 5.5) and the Fish and Aquatics Instream Flow Study (Section 8.5). Likewise, the 7th
component, Water Quality is linked to both the Water Quality Study (Section 5.5) as well as Fish
and Aquatics Instream Flow Study (Section 8.5).
7.5.4.1.1. Existing Data Synthesis
Data from prior Susitna River hydroelectric evaluations and other studies will be used to help
develop a detailed reference source of available data to support the study elements and GW/SW
interactions and processes related to potential Project operations and design. The addition of the
historical data will help provide a more thorough review of the geohydrology of the watershed
and relevant GW/SW interactions and how they may change under the various Project
operational designs. The use of existing information will also help meet the need for detailed
analysis under the proposed Project timeframe. The specific steps of the data synthesis include
the following:
Identify existing reports and data from the 1980s licensing effort, prior studies, and more
recent studies that relate to geology and geohydrology of the Susitna River watershed and
GW/SW interactions and related aquatic habitat in the Susitna River. The reference
search will include any information related to the past geohydrology studies, groundwater
data and information related to main channel interactions, and impacts of winter ice cover
and thickness on groundwater and surface-water interactions.
Identify and review similar studies, reports and data for hydroelectric projects in northern
latitudes and cold regions and any references related to GW/SW interactions. The
literature search for this task will be coordinated with the University of Alaska Fairbanks
– Geophysical Institute research library, which already contains extensive references to
northern research basins and circumpolar literature sources.
Identify applicable geology, soils, and other geohydrologic references for the Susitna
River watershed. Information will be used that is collected by the Geology and Soils
Characterization Study (Section 4.5). Water quality data and references will be provided
by the Baseline Water Quality Study (Section 5.5) for groundwater and surface water
(Figure 7.5-3). Additional water quality data will be provided by the Fish and Aquatics
Instream Flow Study (Section 8.5) historical information reviews.
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7.5.4.1.1.1. Work Products
The information and data obtained as part of this review will provide valuable background
information for the Groundwater Study and will also be integrated into appropriate sections of
the Initial Study Report (Initial Study Report). In addition, this component will provide:
A searchable and annotated bibliography of references and data sources for use by study
teams and resource agencies. The annotated bibliography will be coordinated with the
Alaska Resources Library and Information Services (ARLIS) resource library staff to
follow their Susitna reference standards. The annotated bibliography will be provided to
ARLIS as part of its Project resource collection program.
7.5.4.1.2. Geohydrologic Process-Domains
Project operations could influence GW/SW interactions at different locations along the river,
from the proposed dam and reservoir location to below the Three Rivers Confluence. Site-
specific groundwater studies will help characterize these influences for key aquatic habitat and
riparian study areas within selected Focus Areas. This will be done by first defining the
significant geohydrologic units in the Susitna basin that provide groundwater recharge to the
mainstem and associated main channel, side channels, side sloughs, upland sloughs and
wetlands. ASTM standard D5979 “Standard Guide for Conceptualization and Characterization
of Groundwater Systems” will be used to help define the geohydrologic units (ASTM 2008b).
ASTM D6106 “Standard Guide for Establishing Nomenclature of Groundwater Aquifers” will
be used to help establish the aquifer nomenclature and naming of geohydrologic features (ASTM
2010a). The geohydrologic units (e.g., bedrock, alluvial) will then be related to geomorphologic
and riparian mapping units (process-domain river segments) in coordination with the
Geomorphology Study (Section 6.5) and Riparian Instream Flow Study (Section 8.6) studies
(Montgomery 1999). The geohydrologic units serve as a background layer to riparian process
domains, similar to soil or geology map units. The definition of geohydrologic units is
independent of riparian, fish or aquatic habitat definitions.
The next step will be to define the groundwater regional scale relationship to local flow systems
in the Middle River and Lower River segments and the relationship with the process-domain
river segments. This will be based on methods used on a similar study for the Tanana watershed,
as reported by Anderson (1970). ASTM standard D6106 will be used to help characterize the
groundwater aquifers relevant to Project proposed operations. The final step will be identifying
the relationship between the process-domain river segments and the planned Focus Areas. This
will facilitate the expansion of the analysis of potential Project effects on GW/SW interactions
from the Focus Areas individual study areas back to the larger process-domain river segments.
7.5.4.1.3. Work Products
The results of this study component will be incorporated into appropriate sections of the Initial
Study Report, to be filed with FERC in February 2014. The analysis presented will include:
A detailed description of the significant geohydrologic units in the Susitna basin that
provide groundwater recharge to the mainstem and associated main channel, side
channels, side sloughs, upland sloughs and wetlands.
Descriptions and references defining geohydrologic units.
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Relationship between geohydrologic map units and Focus Areas.
GIS map layers of the geology a geohydrologic units that are defined.
An approach for expanding the site specific Groundwater Study results from the Focus
Areas to the process-domain river segments.
7.5.4.2. Watana Dam/Reservoir
Project construction and operation may influence groundwater conditions downstream of the
dam and the characteristics of the discontinuous permafrost conditions in the vicinity of Project
operations. Variation in reservoir levels will result in transient head conditions on the upstream
side of the dam. Project Engineering Feasibility Studies (ongoing), the Geotechnical
Investigation Program and the Geology and Soils Characterization Study (Section 4.5) will
provide information to help evaluate the groundwater conditions in the Project area and evaluate
the potential for groundwater impacts downstream of the dam. This will be accomplished by
first evaluating engineering geology information from the dam and reservoir area. This
information will be obtained from the Geology and Soils Characterization Study (Section 4.5)
and past geotechnical studies of the proposed dam location (Figure 7.5-3). This will include
geologic well logs, pump tests, seismic data if available, permafrost information, and water leve l
records. The analysis will require close coordination with engineering, as well as the
Geomorphology and Fluvial Geomorphology Modeling studies in the Middle River Segment
(Sections 6.5 and 6.6, respectively). This will be important for identifying and applying data
from existing programs and determining the need for additional data collection.
Based on the information, a description of the pre-Project groundwater conditions will be
developed in the vicinity of the Watana Dam and Reservoir. This will include a characterization
of known permafrost and bedrock hydrogeology in the Watana Dam vicinity. From this,
conceptual GW/SW models will be developed that describe pre-Project conditions and post-
Project conditions. These models will assist in identifying key potential groundwater flow
pathways with the Project (e.g., Deadman Creek drainage) and how the proposed dam
construction may affect groundwater flow. The engineering design of the dam includes a goal of
grouting all groundwater pathways that could be subject to bypass groundwater flow in the
vicinity of the dam. The models will also be used to evaluate the potential changes in
groundwater flow as a result of Project operations.
The operation of the proposed reservoir will also result in riparian habitat loss due to permanent
inundation below the low pool level. Existing riparian and aquatic habitat at the upstream end of
the reservoir will be inundated for different durations between the low pool and high pool
elevations. To evaluate this, field reconnaissance trips will be conducted to collect site specific
data in late summer and early fall to help characterize the area. Mapping data from the
Geomorphology Study (Section 5.5) and the Vegetation and Wildlife Habitat Mapping Study
(Section 11.5), along with existing aerial and LiDAR GIS information will will be used to
develop maps and cross-sections of the study area. This combined information will be used to
evaluate the timing and durations of inundation of the potential riparian and aquatic habitats in
the area at the upstream end of the reservoir. Inundation timing and duration curves will be
produced. Channel Profile and cross-sections will also be produced.
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7.5.4.2.1. Work Products
Information provided from this study component will include:
Documentation of geologic cross-sections, groundwater data, photos, survey data,
geotechnical information, geologic well log, and available seismic data.
Conceptual model of the geohydrology of the dam area, including potential pathways for
groundwater flow in the area of the proposed Dam.
GIS map layers of the geology, and geohydrologic units and features near the proposed
Watana Dam site.
7.5.4.3. Upwelling / Springs Broad-Scale Mapping
This study component is focused on determining the locations of areas in the Middle River
Segment and upper portion of the Lower River Segment that are currently influenced by
groundwater inflow. This will rely upon work products that will be developed from several other
resource studies including the Ice Processes Study (Section 7.6), Geomorphology Study (Section
6.5) and the Water Quality Study (Section 5.5). These studies will collectively provide a suite of
broad-scale maps that will be used in identifying areas of groundwater influence. This
component of the Groundwater Study will provide for the compilation, review and interpretation
of the different mapping work products and will result in development of a GIS map layer that
depicts groundwater influenced areas. This work will be closely coordinated with the Fish and
Aquatics Instream Flow Study and Riparian Instream Flow Study. The identification of these
areas will be important for understanding the spatial extent to which Project induced effects to
existing GW/SW interactions may occur, and from a planning perspective, will help inform the
selection of specific Focus Areas warranting detailed groundwater study.
This study will rely on the following activities and work products that will be provided from
other resource studies:
Aerial and global positioning system (GPS) mapping of winter open leads, in Q1 and Q2
of 2013, and 2014 as completed by the Ice Processes Study (Section 7.6) (Figure 7.5 -3).
Open leads in the Middle River Segment will be compared with the location of open
leads documented in 1984–1985, as appropriate. To provide some context, air
temperatures from 1984–1985 will be compared with air temperatures measured during
the 2012–2013 and 2013–2014 winter seasons from the closest long-term monitoring site
with data covering both periods. Geographic Information S ystem (GIS) coverages of
open leads will be developed. The Groundwater Study will focus on the entire Middle
River Segment and the upper portion of the Lower River Segment upstream from RM 84
(located near USGS Gage on Susitna River at Sunshine).
Aerial photography and aerial videography of the ice-free period showing turbid and
clear water habitat that was completed in Q3 and Q4 2012 as part of the Geomorphology
Study (Section 6.5) and Characterization of Aquatic Habitats Study (Section 9.9). The
aerial photography and videography will be used in part to document turbid and clear
water (i.e., groundwater-influenced) habitats. Clear water inflow from side drainages
(e.g., Portage Creek) will be separated from that dominated by groundwater recharge
(upwelling).
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Thermal Infrared Imagery (TIR) of the Middle River Segment of the Susitna River as
provided from a pilot study to be completed during Q1 2013 as part of Water Quality
Study (Section 5.5). In coordination with the Fish and Aquatics Studies (Section 9) a
determination will be made about the value of the TIR and whether additional imaging
data should be collected in the Lower River Segment or in other portions of the Middle
River Segment. If TIR can successfully identify spatially discrete areas of groundwater
upwelling as validated through on-the-ground confirmatory surveys, then these areas can
be mapped within the entire river segment.
Observational data concerning GW/SW interactions collected as part of the Habitat
Suitability Criteria (HSC) studies associated with spawning and/or rearing fish conducted
under the Fish and Aquatics Instream Flow Study (Section 8.5.4.5.1.1.4) as well as fish
tracking studies completed as part of the Salmon Escapement Study (Section 9.7). In
these studies, where aggregations of spawning or rearing fish are observed, temperature
probes test whether or not upwelling is present by using temperature profiling techniques
(e.g., measuring the vertical temperature profile or measuring the temperature along the
bottom of the river along a transect).
Characterize the identified upwelling/spring areas at a reconnaissance level to determine
if the identified upwelling/spring areas using the methods outlined above are likely either
to be (1) main flow/stage dependent, (2) regional/upland groundwater dependent, or (3)
mixed influence.
7.5.4.3.1. Work Products
This component of the Groundwater Study will provide for the compilation, review and
interpretation of the different mapping work products and will result in development of a GIS
map layer depicting groundwater upwelling and influenced areas. Results will be provided in
appropriate sections of the Initial Study Report. Information resulting from this study
component will include the following:
GIS map layer of upwelling and groundwater influenced areas.
Analysis of the identified upwelling/spring areas to determine if they are (1) main
flow/stage dependent, (2) regional/upland groundwater dependent, or (3) of mixed
influence.
7.5.4.4. Riparian Vegetation Dependency on Groundwater / Surface Water
Interactions
This study component is directly linked to the Riparian Instream Flow Study and associated with
a number of other multidisciplinary resource studies that will be jointly working on the Focus
Areas including the Fish and Aquatics Instream Flow Study (RSP- Section 8.5), Geomorphology
Study (Section 6.5, Ice Processes Study (Section 7.6), and Water Quality Study (Section 5.5).
Figure 7.5-3 shows the relationship between these studies and the Groundwater Study. The
overall goal of this study component is to collect information and data to define GW/SW
interactions and relationships to riparian community health and function at a number of Focus
Area locations so results can be used to scale up to other locations in the river. These
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relationships will then allow for a determination of how Project operations may influence
GW/SW interactions and the riparian communities at unmeasured areas.
This will be accomplished in part through development of physical groundwater models
(Montgomery 1999) at Focus Areas applicable for evaluating riparian community structure.
Physical models, including surface water hydraulic (1-D and 2-D), geomorphic reach analyses,
GW/SW interactions, and ice processes will be integrated such that physical process controls of
riparian vegetation recruitment and establishment can be quantitatively assessed (see Section 8.6)
under both existing conditions and under different Project operations.
Empirical data will be collected at the Focus Areas to define GW/SW interactions. This will
include the use of piezometers, stage recorders, thermographs, dissolved oxygen recorders and
selected water quality meters (conductivity, pH, turbidity). These data will be collected along
linear transect arrays of groundwater wells, piezometers, and stage gages. Wells will be placed
to help describe the hydrologic conditions at internal boundaries (such as sloughs, side channels)
and at varying distances from these boundaries to help measure the time lag in groundwater level
response to changes in surface water stage. Well locations will take into account the riparian
vegetation mapping units. Some wells will be placed at boundaries of the groundwater model
simulation domains to provide model boundary input data, or validation data sets. Additional
information, such as unfrozen volumetric soil moisture content and soil temperature profiles will
be measured to help understand the characteristics of active freeze/thaw processes and moisture
transfer from infiltration and underlying dynamic groundwater tables in the soil horizon critical
to riparian root zones. Table 7.5-1 shows a listing of the data collection system sensors and
measurements. The data will be used to quantify, and model, the relationship between floodplain
shallow surface aquifers and floodplain plant community types.
Precipitation data will also be measured at the Focus Areas. Shielded summer precipitation
gages will be installed in early spring 2013 in time for the 2013 summer season. This
information will be compared with the recent update to the statewide precipitation evaluation and
new index maps. Additionally, precipitation information collected by the Glacier and Runoff
Changes Study (Section 7.7) will be incorporated into the precipitation analysis for the Focus
Areas.
In groundwater wells and surface water measurement stations, the minimum recording interval
for water levels, temperature, and other parameters will be 15 minutes. There will be some
locations close to surface water sources where stage changes are expected to be rapid; for these
areas, data collection intervals may be reduced down to one minute. In all cases, hourly
maximum, minimum, and average values will be recorded, as well as daily statistics. The data
collection intervals are intended to provide data for studying and understanding transient
pressure pulses in the GW/SW systems and to provide both input and calibration data sets for
groundwater model development and simulations goals. The current network of surface flow
gaging stations started in the summer of 2012 will continue operation through 2014. Technical
evaluations will be made in the summer of 2014 about which gaging stations need to be operated
during Q4 2014 and Q1 2015. Groundwater monitoring programs will begin on a small scale in
winter 2012-2013 and increase during the summer of 2013. The monitoring of groundwater wells
will continue into 2014. At that time, a subset of the groundwater wells may be monitored for the
winter of 2014-2015.
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Monitoring wells will be surveyed with a combination of RTK survey methods and optical level
loop methods. This will be done at least two times a year, or more frequent ly if well movements
are recorded. Pressure transducer measurements will be verified with manual measurements at
least monthly during summer months, and three to four times during winter periods. Both
calibration (for determining offsets) and verification water levels will be collected. Calibration
checks will be performed on conductivity and temperature sensors before field installations, and
field calibration checks will be performed monthly during summer months. Calibration checks
during winter months will be performed at least once during the mid-winter period when safe
access and weather conditions allow, and before spring break-up and fall freeze-up.
The Groundwater Study will provide a time series of measured and simulated groundwater levels
and will provide summary statistics needed for developing plant-response curves (see Riparian
Instream Flow Study, Section 8.6). The groundwater and surface water field measurements for
continuously monitored stations will be 15 minutes or less. Model simulations will also be 15
minutes or less, based on analysis of modeling results. This information will produ ce time series
data sets from which water level summary statistics can be calculated for a range of analysis
objectives, such as running averages in hourly and daily increments.
Where appropriate, MODFLOW (Feinstein et al. 2012; Maddock et al. 2012; USGS 2005, 2012)
GW/SW interaction models of floodplain shallow alluvial aquifer and surface water relationships
will be developed. The selection of MODFLOW modeling package will utilize ASTM D6170
“Standard Guide for Selecting a Groundwater Modeling Code” as the guideline for documenting
the code selection process (ASTM 2010b). MODFLOW GW/SW interaction models will be used
to model GW/SW relationships using empirical monitoring data collected at the Focus Areas.
Similar approaches to understanding GW/SW interactions have been reported in Nakanishi and
Lilly 1998. ASTM standard D6170 will also be used to help determine the model code and
approach used for analysis (ASTM 2008b). ASTM standard D5981 will be used to help develop
calibration goals and procedures for groundwater modeling efforts (ASTM 2008c). Both generic
and interpretative models will be used to help improve process understanding and design of data
collection field programs, and for developing the framework for predictive models that will
simulate Project effects. The application of snowmelt and precipitation runoff stage-change
events will be used to develop and calibrate groundwater models, and independent hydrologic
events will be used to validate the models. Thus, a year with snowmelt peak and three
precipitation peaks may provide three peaks for model development and calibration and one
event to validate the model simulation capabilities. Figure 7.5-4 illustrates the use of snowmelt
or precipitation peaks for collection of data for hydrologic model (surface and groundwater)
development, calibration, and validation. The daily discharge for the last three years is shown to
illustrate how future hydrologic data will be used with the modeling development planned for the
study. Data from the 2013–2014 study periods will be used to provide information similar to that
provided for the period of record shown in the figure. The interaction between the river stage
changing and adjacent groundwater is shown in Figure 7.5-5. An example of GW/SW
interactions is shown in Figure 7.5-6 for the Chena River and a line of adjacent wells installed at
varying distances from the river up to 8,800 feet away (Nakanishi and Lilly 1998). The Chena
River stage is shown on the left, with groundwater levels show for wells that are increasing
distances away from the Chena River. The spring snowmelt peal and two primary precipitation
peaks in the Chena River can be seen in each of the groundwater hydrographs shown. The
pressure response to the river stage changes is illustrated by each of the groundwater
hydrographs. The three main stage peaks on the Chena River are shown in each well out to the
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farthest well 8,800 feet away. Figure 7.5-7 illustrates the application of river and groundwater
levels being used as boundary conditions for a two-dimensional groundwater flow model.
Example groundwater, surface-water, and meteorological data collection networks for a typical
Focus Area is shown in Figure 7.5-8. This figure illustrates wells placed along transect
locations, along surface-water hydrologic boundaries, and various riparian zones. The same
approach will be used for the Fish and Aquatics Instream Flow Study as displayed in Figure 7.5 -
9.
7.5.4.4.1. Work Products
This component of the Groundwater Study will provide for the installation, data collection
efforts and analysis of the GW/SW interactions and will support the Riparian Instream Flow
Study (Section 8.6). Results will be provided in the Initial Study Report, to be filed with FERC
February 2014. The study component will result in the following work products:
Data collection networks and stations metadata, including data collection standards and
methods, wiring diagrams, programs, horizontal and vertical survey control network data.
Groundwater, surface water, meteorological, geotechnical (soil temperature, soil
moisture) data sets.
Groundwater modeling archived flow models, model input and calibration data sets and
files, groundwater model documentation.
7.5.4.5. Aquatic Habitat Groundwater / Surface- Water Interactions
The same general approach as described above for the riparian component will be used for
evaluating GW/SW interactions within aquatic habitats as part of the Fish and Aquatics Instream
Flow Study (Section 8.5) (see Figure 7.5-9). Hydraulic unsteady flow routing will help identify
water surface elevations. The mainstem flow routing model will serve to predict water surface
elevations under different flow conditions longitudinally throughout the length of the river below
the Watana Dam site (RM 184). The model will thus be able to predict water surface elevations
(WSEs) proximal to the Focus Areas noted above, as well as other areas identified as being
groundwater-influenced. The WSEs empirically measured in side channels, sloughs, and
groundwater wells installed in the floodplain at the Focus Areas can therefore be related to
mainstem WSEs, allowing for a detailed analysis of spatial and temporal changes in WSE under
different operating conditions, including base load and load-following scenarios.
Habitat Suitability Criteria (HSC) and a Habitat Suitability Index (HSI) will be developed that
include groundwater-related parameters (upwelling/downwelling). Development of HSC and
HSI will follow the general procedures outlined in the Fish and Aquatics Instream Flow Study
(Section 8.5). Parameters specific to groundwater that will be measured, where appropriate,
include turbidity, evidence of upwelling/downwelling currents, substrate characteristics, and
water temperature. Other parameters may also be included. These parameters will be
incorporated into the development of HSC type curves that reflect utilization of these parameters
by fish. This work will be closely coordinated with the fish studies (Section 9).
Mainstem, side channel, slough habitat models will be developed that incorporate GW/SW
related processes (main channel head, upwelling/downwelling) (see Figure 8.5-3 in Section 8.5,
Fish and Aquatics Instream Flow Study). An integral part of the Fish and Aquatics Instream
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Flow Study will be development of habitat-specific models that can be used in evaluating flow
(and WSE) relationships between the mainstem river and other habitat types (including those
influenced by groundwater) under different operational scenarios. These types of models (e.g.,
flow routing) are generally described in more detail in the Fish and Aquatics Instream Flow
Study (see Section 8.5).
The groundwater aquatics study is coordinating with both instream flow and fisheries studies on
the selection of Focus Areas. The groundwater study will be measuring both horizontal and
vertical head gradients through combinations of nested wells installed at different depths and
shallow wells installed in surface water habitat areas to measure the gradients between surface
water sources and underlying groundwater conditions. Details on the measurement of fluxes are
described in Section 7.4.5. These gradients will be compared with simulated gradients from
groundwater/surface water models under the field conditions measured in 2013 and 2014 and
compared with Project operation scenarios. Example groundwater, surface-water, and
meteorological data collection networks for a typical Focus Area is shown in Figure 7.5-9. This
figure illustrated wells placed along transect locations, along surface-water hydrologic
boundaries, and various riparian zones. The same approach will be used for evaluating aquatic
habitats within Focus Areas, with less of a focus on riparian zones and more on surface-water
habitat (main channel, side channel, side slough, upload slough) features. The application of 3D
and 2D groundwater flow models is illustrated in this same example in Figure 7.5-10. This figure
also shows the addition of several wells to provide water-level information for boundary
conditions at several of the groundwater model boundaries. Figure 7.5-11 illustrates some of the
interaction that may take place between groundwater and surface water. The top figure shows a
typical cross across the floodplain, main channel, side channel or slough and island. Example
fluctuation surface water levels and groundwater tables are illustrated. The fluctuations driven by
river station during the summer will be transient and vary each year. The lower portion of the
figure shows how the Susitna River at Gold Creek stage has varied between 2005 and 2009.
These fluctuations in stage will create fluctuations in water table levels which can be used to help
define geohydrologic properties. This example illustrates a number of concepts that will be
applied to all of the geohydrologic cross-sections and resulting data stations supporting the
riparian and aquatic analysis efforts.
The Groundwater Study will be responsible for the coordination and collection of information,
analysis and reporting of final deliverables for this study element.
7.5.4.5.1. Work Products
This component of the Groundwater Study will provide for the installation, data collection
efforts and analysis of the GW/SW interaction important for support of the Fish and Aquatic
Instream Flow Study (Section 8.5). Results will be provided in the Initial Study Report, to be
filed with FERC in February 2014. Information provided will include the following:
Data collection networks and stations metadata, including data collection standards and
methods, wiring diagrams, programs, horizontal and vertical survey control network data,
well logs.
Groundwater, surface water, meteorological, geotechnical (soil temperature, soil
moisture) data sets.
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Groundwater modeling archived flow models, model input and calibration data sets and
files, groundwater model documentation.
7.5.4.6. Water Quality in Selected Habitats
Water quality characteristics are likely to vary with GW/SW interactions and potential impacts
due to proposed Project operations. Project water quality activities will be coordinated with the
Riparian Instream Flow Study (Section 8.6), Geomorphology studies (Sections 6.5 and 6.6), and
Fish and Aquatics Instream Flow Study (Section 8.5). The work under this objective will be
accomplished by the Baseline Water Quality Study (Section 5.5). The following methods will be
used in coordination with the indicated studies to understand water quality characteristics and the
variation between groundwater and surface water. This will help evaluate the potential changes
in water quality related to GW/SW interactions and potential impacts related to proposed Project
operations.
At selected instream flow, fish population, and riparian study sites, basic water chemistry
(temperature, DO, conductivity, pH, turbidity, redox potential) data will be collected that define
habitat conditions and characterize GW/SW interactions (Section 5.5). For example, where
possible, differences between groundwater representative of regional groundwater conditions,
groundwater in the mixing zone at the GW/SW interface (slough or river bed), and surface water
sources (sloughs and side channels) will be characterized.
Water quality differences will be characterized between a set of key productive aquatic habitat
types (three to five sites) and a set of non-productive habitat types (three to five sites) that are
related to the absence or presence of groundwater upwelling to improve the understanding of the
water quality differences and related GW/SW processes. For example, results from fish
population and habitat studies (Sections 9.6 and 9.9) will be used and coordinated with the Fish
and Aquatics Instream Flow Study (Section 8.5) to select paired productive and non-productive
habitats.
7.5.4.6.1. Work Products
This component of the Groundwater Study will provide for the installation, data collection
efforts and analysis of the GW/SW - waterquality interactions important for support of the Fish
and Aquatic Instream Flow Study (Section 8.5). Results will be provided in the Initial Study
Report, to be filed with FERC February 2014. Information provided will include the following:
Data collection networks and stations metadata, including data collection standards and
methods, wiring diagrams, programs, horizontal and vertical survey control network data,
well logs.
Groundwater, surface water, meteorological, geotechnical (streambed temperature) data
sets, including water quality meter and sensor calibration and calibration validation data
and forms.
Groundwater modeling archived flow models, model input and calibration data sets and
files, groundwater model documentation.
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Water quality differences between a set of key productive aquatic habitat types (three to
five sites) and a set of non-productive habitat types (three to five sites) that are related to
the absence or presence of groundwater upwelling.
7.5.4.7. Winter Groundwater / Surface Water Interactions
Winter GW/SW interactions are critical to aquatic habitat functions. Proposed Project operations
will have an impact on the winter flow conditions of the mainstem and side channels and
sloughs. The collection of hydrologic conditions (i.e., water levels, discharge, ice conditions) is
critical to understanding current winter flow conditions and evaluating the potential impacts of
Project operations.
Water levels/pressure will be measured at the continuous gaging stations on the Susitna River
during winter flow periods. Continuous gaging stations will be measuring water levels and
temperature as part of the instream flow studies. Water levels measured during full ice cover are
generally referred to as water pressure and represent the hydrostatic head of the river. The
Project is expected to increase average monthly flows in the Susitna River during the winter
months, and this may have an impact on GW/SW interactions during that season.
Winter discharge measurements will help identify key sections of the mainstem with
groundwater baseflow recharge to the river (upwelling). Winter discharge will be measured as
part of the instream flow study (Section 8.5) and in coordination with U.S. Geological Survey
(USGS) winter measurement efforts at USGS gaging stations to identify winter gaining and
losing reaches. These field activities will be closely coordinated with the Ice Processes Study
(Section 7.6).
In Focus Areas, channel/slough temperature profiles will be measured to help characterize the
GW/SW interactions and temporal variations over the winter flow season.
The Groundwater Study will be responsible for the coordination and collection of information,
analysis and reporting of final deliverables for this study element.
7.5.4.7.1. Work Products
This component of the Groundwater Study will provide for the data collection efforts and
analysis of the winter GW/SW interactions important for support of the Fish and Aquatic
Instream Flow Study (see Section 8.5). Results will be provided in the Initial Study Report, to be
filed with FERC February 2014. Information provided will include the following:
Groundwater, surface water, meteorological, geotechmical (streambed temperature,) data
sets, including water quality meter and sensor calibration and calibration validation data
and forms.
7.5.4.8. Shallow Groundwater Users
There are a number of groundwater wells located in the Susitna River floodplain that have
demonstrated the interconnections between groundwater and surface water. The influence of
proposed Project operations could change water levels and water quality in water supply wells.
A majority of the wells are expected to be private homeowner wells. The methods listed below
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will be used to evaluate the potential impacts of the Project on water supply wells in the area
under potential impact by the Project:
The Alaska Department of Natural Resources Well Log Tracking System (WELTS) and
the USGS Groundwater Site Inventory (GWSI) Database will be used to map domestic
and other water supply wells along the Susitna River downstream of the proposed
Watana Reservoir.
At a reconnaissance level, wells will be stratified by potential to be affected by the
Susitna River flow regime (high, medium, and low) using factors such as depth and
proximity to the Susitna River. A small number of representative wells will be selected
with high potential to be affected by the Susitna River flow regime and well levels and
river stage will be monitored. River stage information will come from correlations with
the gaging stations measuring water levels that are part of the instream flow studies.
Based on the results from the well monitoring and an analysis of potential Project
operations flow data, the potential effects of the Project will be determined on shallow
groundwater wells and it will be determined if additional monitoring of wells may be
appropriate. ASTM method D6030 will be used to help address groundwater
vulnerability (ASTM 2008a).
The data from this study element will also be used for the other study elements, where
appropriate, to help extend the application of the data and analysis regarding shallow
groundwater well users to other Groundwater Study objectives.
The Groundwater Study will be responsible for the coordination and collection of information,
analysis and reporting of final deliverables for this study element.
7.5.4.8.1. Work Products
This component of the Groundwater Study will provide for the install ation, data collection
efforts and analysis of the GW/SW interaction important for private groundwater well users.
Results will be provided in the Initial Study Report, to be filed with FERC February 2014.
Information provided will include the following:
Data collection stations metadata, including data collection standards and methods,
wiring diagrams, programs, horizontal and vertical survey control network data, well
logs.
Groundwater and surface water data sets.
7.5.5. Consistency with Generally Accepted Scientific Practice
The proposed study methodology was cooperatively developed with the assistance of science and
technical experts from state and federal management agencies. Many of these technical experts
have experience in multiple FERC licensing and relicensing proceedings. The methods for data
collection, data analysis, modeling, and interpretation are consistent with common scientific and
professional practices. ASTM and USGS standards and practices will be used with each study
component, as applicable. The scope of each of the studies is consistent with common
approaches used for other FERC proceedings and reference specific protocols and survey
methodologies, as appropriate.
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7.5.6. Schedule
The groundwater study will occur during the 2013 and 2014 study period (Table 7.5-2).
Coordination with other studies will occur throughout the licensing period (Figures 7.5-3, 7.5-4,
7.5-5). The collection of information for the existing data synthesis will be initiated at the
beginning of the study period and be completed by the end of summer 2013. The definition and
development of geohydrologic process domains and terrains will take place in the same time
period to help guide other study design and field efforts during the summer of 2013.
Winter focus studies will begin with existing data collection activities started in 2012 and
increase with the installation of data collection systems in study sites in early summer 2013.
Data from water quality, instream flow, and other studies will be provided after data quality
assurance review has been completed, normally within a month of data collection in the field.
Coordination with each of the associated studies providing data will occur at the beginning of the
study period and be part of the schedules for each stud y. The Initial Study Report and the
Updated Study Report will be issued February 2014 and February 2015, respectively. Updates on
study progress will be presented at Technical Workgroup meetings, to be held quarterly during
2013 and 2014.
7.5.7. Relationship to Other Studies
The Groundwater Study is designed to interact and support a number of other studies. It is
providing data, references, process understanding on groundwater/surface-water interactions to
help determine the potential effects of Project operations on various natural resources, such as
riparian and aquatic, and the public, primarily for shallow groundwater well users. The
following sections describe the relationship of each study element to other environmental and
engineering studies. Some of the study elements also support other Groundwater Study
elements.
7.5.7.1. Existing Data Synthesis
The existing data synthesis will coordinate and use data from other studies, such as Geology and
Soils Characterization (Section 4.5), Baseline Water Quality Study (Section 5.5),
Geomorphology (Section 6.5), Fish and Aquatics Instream Flow Study (Section 8.5), and
Riparian Instream Flow Study (Section 8.6) but will not be dependent on the other studies as the
primary focus of the synthesis is geohydrology information. The synthesis will coordinate with
the major library networks (ARLIS and UAF Geophysical Institute Library), the Alaska
Department of Natural Resources, Division of Geological and Geophysical Surveys, and USGS
information sources and information specialists. The products of this study element can be used
by all study groups as needed, but are designed primarily to support the additional Groundwater
Study objectives. These independencies are illustrated in Figure 7.5-3.
7.5.7.2. Geohydrologic Process-Domains and Terrain
The geohydrologic process domain study element will primarily obtain its data from sources
found in the data synthesis and statewide data sources at Alaska Department of Natural
Resources and UAF-GINA (Figure 7.5-3). The products generated for this study element will be
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available to all studies, but will primarily be needed by Fish and Aquatics Instream Flow Study
(Section 8.5), and Riparian Instream Flow Study (Section 8.6).
7.5.7.3. Watana Dam/Reservoir
The study objectives for the proposed Watana Dam area will require coordination with the
Engineering Feasibility Studies (ongoing) Geotechnical Investigation Program and the Geology
and Soils Characterization Study (Section 4.5) (Figure 7.5-3). The study will coordinate any
data collection activities with these two projects. Geotechnical drilling and potential well
installations will be under the engineering studies. The products from this study element will be
available to all studies, but no studies have specific dependencies on the information. The
information will support the general assessments of aquatic habitat and potential Project effects.
7.5.7.4. Upwelling / Springs Broad-Scale Mapping
This study element has specific dependencies on Baseline Water Quality Study (Section 5.5), Ice
Processes Study (Section 7.6) and Fish and the Aquatics Instream Flow Study (Section 8.5)
(Figure 7.5-3). The Groundwater Study will use the observations of open leads, water quality
(temperature, conductivity), thermal imaging, winter discharge measurements, hydrologic data
collection network data for the broad-scale mapping of the groundwater discharge (upwelling)
areas. This information will primarily be used by Fish and Aquatics Instream Flow Study
(Section 8.5), and Riparian Instream Flow Study (Section 8.6) for ha bitat assessment and
upscaling of Focus Area studies to unmeasured sites (see Section 8.5.4.7).
7.5.7.5. Riparian Vegetation Dependency on Groundwater / Surface Water
Interactions
This study element will have a number of active dependencies to other projects, primarily to the
Riparian Instream Flow Study (Section 8.6) (Figure 7.5-3). Other important studies providing
data input to this study element are Baseline Water Quality Study (Section 5.5), Geomorphology
(Section 6.5), Fluvial Geomorphology Modeling Below Watana Dam Study (Section 6.6), Ice
Processes Study (Section 7.6), and Fish and Aquatics Instream Flow Study (Section 8.5).
Coordination with the Riparian Instream Flow Study will be ongoing, with data collection and
analysis activities conducted jointly by both studies. Riparian study leads will provide priorities
and input to the groundwater leads throughout the project. The primary user of the products
from this study element is the Riparian Instream Flow Study (Section 8.6).
7.5.7.6. Aquatic Habitat Groundwater / Surface Water Interactions
This study element will have a number of active dependencies to other projects, primarily to the
Fish and Aquatics Instream Flow Study (Section 8.5) (Figure 7.5-3). Other important studies
providing data input to this study el ement are Baseline Water Quality Study (Section 5.5),
Geomorphology (Section 6.5), Fluvial Geomorphology Modeling Below Watana Dam Study
(Section 6.6), Ice Processes Study (Section 7.6), and Riparian Instream Flow Study (Section 8.6).
Coordination with the Fish and Aquatics Instream Flow Study will be ongoing, with data
collection and analysis activities conducted jointly by both studies. Aquatics study leads will
provide priorities and input to the groundwater leads throughout the Project. This study element
will closely coordinate between the riparian and aquatics studies on activities in the Focus Areas
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where data collection networks will be optimized to serve the objectives of both studies and limit
unneeded duplication. The primary user of the products from this study element is the Fish and
Aquatics Instream Flow Study (Section 8.5).
7.5.7.7. Water Quality in Selected Habitats
This study element will have a number of active dependencies to other projects, primarily to the
Baseline Water Quality Study (Section 5.5) and Fish and Aquatics Instream Flow Study (Section
8.5) and the Study of Fish Distribution and Abundance in the Middle and Lower Sustina River
(Section 9.6) (Figure 7.5-3). Coordination with the Fish and Aquatics Instream Flow Study will
be ongoing, with data collection and analysis activities conducted jointly by both studies.
Aquatics study leads will provide priorities and input to the groundwater leads throughout the
Project. This study element will closely coordinate between the chemistry and aquatics studies
on activities in the Focus Areas where data collection networks will be optimized to serve the
objectives of both studies and limit unneeded duplication. The primary user of the products from
this study element is the Fish and Aquatics Instream Flow Study study (Section 8.5).
7.5.7.8. Winter Groundwater / Surface Water Interactions
This study element will have a number of active dependencies to other studies, primarily to the
Fish and Aquatics Instream Flow Study (Section 8.5) (Figure 7.5 -3) and Ice Processes Study
(Section 7.6). This study element will also involve coordination with USGS winter data
collection efforts. Coordination with the Fish and Aquatics Instream Flow Study will be
ongoing, with data collection and analysis activities conducted jointly by both studies. Aquatics
study leads will provide priorities and input to the groundwater leads throughout the Project.
The primary user of the products from this study element is the Fish and Aquatics Instream Flow
Study (Section 8.5) and the Riparian Instream Flow Study (Section 8.6).
7.5.7.9. Shallow Groundwater Users
This study element will coordinate with Alaska Department of Natural Resources (ADNR) for
identifying shallow groundwater well users. The ADNR-WELTS database and USGS GWSI
database will be used to help identify the number of shallow groundwater well users and
technical details of the wells and water use (Figure 7.5-3). The products from this study element
will also be used to help in the analysis objectives for other Groundwater Study elements.
7.5.8. Level of Effort and Cost
The level of effort for the groundwater study objectives is distributed in this and other studies.
The groundwater study costs reflect the analysis of data collected in this and other studies. The
study objectives and associated primary costs associated with each objective for the 2013–2014
study period are as follows:
7.5.4.1 – Existing Data Synthesis
o Groundwater Study
7.5.4.2 – Geohydrologic Process-Domains and Terrain
o Groundwater Study
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7.5.4.3 – Watana Dam/Reservoir
o Groundwater Study–analysis only
o Engineering, Geology (Section 4.5), Geomorphology (Sections 6.5, 6.6) studies
include field and data collection costs
7.5.4.4 – Upwelling / Springs Broad-Scale Mapping
o Groundwater Study–analysis only
o Ice Processes (Section 7.6), Geomorphology (Sections 6.5, 6.6), Instream Flow
(Section 8.5), and Water Quality (Sections 5.5, 5.6) studies include field and data
collection costs
7.5.4.5 – Riparian Vegetation Dependency on Groundwater / Surface Water Interactions
o Groundwater Study–field installation of groundwater wells and data collection
stations and instrumentation, coordination, and analysis
o Riparian Instream Flow Study (Section 8.6) includes field and data collection
costs
7.5.4.6 – Fish Habitat Groundwater / Surface Water Interactions
o Groundwater Study – field installation of groundwater wells and data collection
stations and instrumentation in combination with Fish and Aquatics Instream
Flow Study (Section 8.5), coordination and analysis
o Fish and Aquatics Instream Flow Study (Section 8.5) also includes field and data
collection costs
7.5.4.7 – Water Quality in Selected Habitats
o Groundwater Study–coordination and analysis only, some sensors in coordination
with riparian and instream flow study elements
o Water Quality (Sections 5.5, 5.6), Fish and Aquatics Instream Flow (Section 8.5)
studies include field and data collection costs
7.5.4.8 – Winter Groundwater / Surface Water Interactions
o Groundwater Study–field data collection, coordination and analysis
o Fish and Aquatics Instream Flow Study (Section 8.5) also includes some field and
data collection costs
7.5.4.9 – Shallow Groundwater Users
o Groundwater Study
The groundwater study costs are estimated to be about $2,000,000 beyond the data collection
costs allocated throughout the studies mentioned above. The final cost will be determined by the
final number of Focus Areas that are selected and included in the riparian and instream flow
studies. The instrumentation, wells installation, and analysis could be $250,000 dependin g on
the scale of each site.
FINAL STUDY PLAN GROUNDWATER STUDY 7.5
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7.5.9. Literature Cited
Anderson, G.S. 1970. Hydrologic reconnaissance of the Tanana Basin, central Alaska, 4 sheets,
scale 1:1,000,000.
Anderson, M.P. and W.W. Woessner. 1992. Applied Groundwater Modeling: Simulation of
flow and advective transport. Academic Press, 372 pp.
ASTM. 2008a. D6030 - 96(2008) Standard Guide for Selection of Methods for Assessing
Groundwater or Aquifer Sensitivity and Vulnerability, ASTM, 9 pp.
ASTM. 2008b. D5979 - 96(2008) Standard Guide for Conceptualization and Characterization
of Groundwater Systems ASTM, 19 pp.
ASTM. 2008c. D5981 - 96(2008) Standard Guide for Calibrating a Groundwater Flow Model
Application, ASTM, 19 pp.
ASTM. 2010a. D6106 - 97(2010) Standard Guide for Establishing Nomenclature of
Groundwater Aquifers, ASTM, 17 pp.
ASTM. 2010b. D6170 - 97(2010) Standard Guide for Selecting a Groundwater Modeling Code,
ASTM, 19 pp.
Beikman, H.M. 1994. Geologic map of Alaska. In Plafker, George, and Berg, H.C., The
Geology of Alaska: Geological Society of America, 1 sheet, scale 1:2,500,000.
Feinstein, D.T., Fienen, M.N., Kennedy, J.L., Buchwald, C.A., and Greenwood, M.M. 2012.
Development and application of a groundwater/surface-water flow model using
MODFLOW-NWT for the Upper Fox River Basin, southeastern Wisconsin: U.S.
Geological Survey Scientific Investigations Report 2012–5108, 124 p.
Harza-Ebasco Susitna Joint Venture. 1984. Lower Susitna River Sedimentation Study Project
Effects on Suspended Sediment Concentration, prepared for Alaska Power Authority,
June.
Jorgenson, M. T., J.E. Roth, M. Emers, S.F. Schlentner, D.K. Swanson, E.R. Pullman, J.S.
Mitchell, and A.A. Stickney. 2003. An ecological land survey in the Northeast Planning
Area of the National Petroleum Reserve–Alaska, 2002. ABR, Inc., Fairbanks, AK. 128
pp.
Kenneson, D.G. 1980a. Surficial Geology of the Susitna-Chulitna River Area, Alaska, Part 1:
Text, Susitna Basin Planning Background Report. Prepared for Land and Resource
Planning Section Division of Research and Development, Alaska Department of Natural
Resources, March 1980. 35 pp.
Kenneson, D.G. 1980b. Surficial Geology of the Susitna-Chulitna River Area, Alaska, Part 2:
Maps, Susitna Basin Planning Background Report. Prepared for Land and Resource
Planning Section Division of Research and Development, Alaska Department of Natural
Resources, March 1980. 27 pp.
Kirschner, C.E. 1994. Sedimentary basins in Alaska. In Plafker, George, and Berg, H.C., The
Geology of Alaska: Geological Society of America, 1 sheet, scale 1:2,500,000.
Locke, A., C. Stalnaker, S. Zellmer, K. Williams, H. Beecher, T. Richards, C. Robertson, A.
Wald, A. Paul and T. Annear. 2008. Integrated Approaches to Riverine Resource
FINAL STUDY PLAN GROUNDWATER STUDY 7.5
Susitna-Watana Hydroelectric Project Alaska Energy Authority
FERC Project No. 14241 Page 7.5-22 July 2013
Management: Case Studies, Science, Law, People, and Policy. Instream Flow Council,
Cheyenne, WY. 430 pp/
Maddock, Thomas, III, Baird, K.J., Hanson, R.T., Schmid, Wolfgang, and Ajami, Hoori. 2012.
RIP-ET: A riparian evapotranspiration package for MODFLOW-2005: U.S. Geological
Survey Techniques and Methods 6-A39, 76 p.
Montgomery, D. 1999. Process domains and the river continuum. Journal of the American
Water Resources Association 35 (2): 397-410.
Nakanishi, A.S., and Lilly, M.R. 1998. Estimate of aquifer properties by numerically simulating
ground-water/surface-water interactions, Fort Wainwright, Alaska: U.S. Geological
Survey Water-Resources Investigations Report 98-4088, 27 p.
Rosenberry, D.O., and LaBaugh, J.W. 2008. Field techniques for estimating water fluxes
between surface water and ground water: U.S. Geological Survey Techniques and
Methods 4-D2.
Sandone, G., and C.C. Estes. 1984. Evaluations of the effectiveness of applying infrared
imagery techniques to detect upwelling ground water. Chapter 10 in: C.C. Estes, and D.S.
Vincent-Lang, editors. Aquatic habitat and instream flow investigations, May-October
1983. Susitna Hydro Aquatic Studies. Report No.3. Alaska Department of Fish and
Game, Anchorage, Alaska. APA Document #1939.
USGS (U.S. Geological Survey). 2005. MODFLOW-2005, The U.S. Geological Survey
modular ground-water model—the Ground-Water Flow Process: U.S. Geological Survey
Techniques and Methods 6-A16.
Viereck, L.A., C.T. Dyrness, A.R. Batten, and K.J. Wenzlick. 1992. The Alaska Vegetation
Classification. Pacific Northwest Research Station, U.S. Forest Service, Portland, OR.
Gen. Tech. Rep. PNW-GTR-286. 278 pp.
Wahrhaftig, Clyde. 1994. Physiographic divisions of Alaska. In Plafker, George, and Berg,
H.C., The Geology of Alaska: Geological Society of America, 1 sheet, scale 1:2,500,000.
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7.5.10. Tables
Table 7.5-1. Data collection parameters and associated sensors that will be used for the Groundwater Studyat selected
Focus Areas.
Process Parameter Sensor Type
Surface-water stage fluctuation Pressure – calculated water levels CSI CS 450 Pressure transducer
Groundwater stage fluctuation Pressure – calculated water levels CSI CS 450 Pressure transducer
Active-layer freezing and thawing Resistance – calculated temperature GWS-YSI Vertical thermistor strings
Active-layer freezing and thawing,
Moisture availability Unfrozen volumetric moisture content (%) CSI CS616 Soil-moisture sensors
Evapotranspiration Air temperature, Relative Humidity CSI HC2S3 AT/RH sensor
Evapotranspiration Wind Speed, Direction RM Yound 05103 WS/WD sensor
Evapotranspiration Radiation CMP3 – Kipp & Zonen Pyranometer
Evapotranspiration Soil-surface temperature GWS-YSI Thermistor
Evapotranspiration Precipitation TI 525-US Tipping bucket rain gage
Plant transpiration Delta-Temperature DI – Dynagage and TDP sensors and
sap flow algorithms
Notes:
1 Campbell Scientific Inc., CSI; Dynomax Inc., DI; Texas Instruments, TI, GW Scientific, GWS.
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Table 7.5-2. Schedule for implementation of the Groundwater Study.
Activity
2012 2013 2014 2015
3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q
7.5.4.1 Existing Data Synthesis
7.5.4.2 Geohydrology Process-Domains and Terrain
7.5.4.3 Watana Dam/Reservoir
7.5.4.4 Upwelling/Springs Broad-Scale Mapping
7.5.4.5 Riparian Vegetation Dependency on SW/GW Interactions
7.5.4.6 Aquatic Habitat GW/SW Interactions
7.5.4.7 Water Quality in Selected Habitats
7.5.4.8 Winter GW/SW Interactions
7.5.4.9 Shallow Groundwater Users
Initial Study Report /Updated Study Report Δ ▲
Legend: Planned Activity
Δ Initial Study Report
▲ Updated Study Report
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7.5.11. Figures
Figure 7.5-1. Sedimentary basins and geologic structure in the Susitna watershed (modified from Kirschner 1994).
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Figure 7.5-2. Geologic units in the Susitna watershed (modified from Beikman 1994).
FINAL STUDY PLAN GROUNDWATER STUDY 7.5
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Figure 7.5-3. Study interdependencies for the Groundwater Study.
Geology and Soils (4)
IFS Fish (8.5)
IFS Riparian (8.6)
Fluvial Geomorphology (6.6)
Ice Processes (7.6)
ADNR/GINA
Mapping Information
Ice Processes (7.6)
Water Quality (5.0)
Geologic and Terrain
Mapping Layers ((Q1-13)
Background Information
(Q1-13)
Geologic Data
Geotechnical Data
Ice and IFS Data
(Q2-Q4-13)
Winter Aerial Surveys
Water Quality
( Q2-Q3-13, Q1-14)
STUDY INTERDEPENDENCIES FOR GROUNDWATER STUDY
Existing Data
Synthesis
Geohydrologic
Process-Domains
and Terrain
Upwelling/
Springs Broad-
Scale Mapping
All Studies
Groundwater Hydrology
and Upwelling
Evaluations
(Q1-14/Q4-14)
Draft Annotated
Bibliography (Q2-13)
Annotated Bibliography
(Q4-13)
Watana
Dam/Reservoir
All Studies
Groundwater
Evaluation
Potential Effects of
Geology and Soils (4)
Fluvial Geomorphology (6.6)
Ice Processes (7.6)
IFS Fish (8.5)
IFS Fish (8.5)
IFS Riparian (8.6)
Draft Process Domain
Mapping (Q2-13)
Process Domain Mapping
(Q4-13)
IFS Fish (8.5)
IFS Riparian (8.6)
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Figure 7.5-3. Study interdependencies for the Groundwater Study (continued).
STUDY INTERDEPENDENCIES FOR GROUNDWATER STUDY
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Figure 7.5-3. Study interdependencies for the Groundwater Study (continued).
STUDY INTERDEPENDENCIES FOR GROUNDWATER STUDY
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Figure 7.5-4. Discharge hydrograph and analysis examples for the Susitna River at Gold Creek.
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Figure 7.5-5. Illustration of groundwater and surface-water interactions with changing stage levels.
Figure 7.5-6. Groundwater responses to stage changes in the Chena River (Nakanishi and Lilly 1998).
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Figure 7.5-7. An example of applying surface water stage conditions and groundwater levels from a well as input to
boundary conditions to a two-dimensional groundwater model (Nakanishi and Lilly 1998).
Figure 7.5-8. Example schematic of groundwater well and surface water station network in a hypothetical Focus Area
targeting riparian analysis.
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Figure 7.5-9. Example schematic of groundwater well and surface water station network in a hypothetical Focus Area
targeting fish and aquatic habitat analysis.
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Figure 7.5-10. Example schematic of a 3D groundwater model grid in a hypothetical Focus Area targeting fish and
aquatic analysis. 2D cross-section models would be developed in this hypothetical case at sections XS1 and XS2.
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Figure 7.5-11. The upper graphic is an example schematic of a 2D cross-section across the floodplain, main channel, and
a side channel or slough. Groundwater and surface water interactions and examples data collection stations are shown.
The lower plots show the daily mean gage height for the Susitna River at Gold Creek.
Water
Table Alder WillowWillowAlder WillowBalsam PoplarWhite Spruce/ Paper BirchPoplar/Alder White Spruce Paper BirchWells, Soil Temperature, Soil Moisture
Stage Recorder
Stage
Recorder
Stage
Recorder
Flood Levels
Fluctuating
Water Table
Regional
Groundwater
Gradient and
Fluctuations
Apr May Jun Jul Aug Sep
2
4
6
8
10
12
14
16
18
Daily Mean Gauge Height, In Feet WY 2005
WY 2006
WY 2007
WY 2008
WY 2009
USGS Susitna River at Gold Creek Gauging Station, 15292000